Background: To preserve its nutritional properties, fish must have good sanitary quality. The objective of this study was to investigate some pathogens contaminating smoked, dried, and braised fish marketed in Ouagado...Background: To preserve its nutritional properties, fish must have good sanitary quality. The objective of this study was to investigate some pathogens contaminating smoked, dried, and braised fish marketed in Ouagadougou. Methodology: Potential pathogens of Enterobacteriaceae and Staphylococcus were screened in eight (8) species of processed fish. The investigation of the germs was carried out following the normative methods of microbiology. The identities of the strains were determined by API 20 E (BioMerieux S.A., France) and API STAPH (BioMerieux S.A., France) kits for Enterobacteriaceae and Staphylococcus species respectively. The uidA gene profile in Escherichia coli isolates was determined by simplex PCR. The identity of Staphylococcus aureus was confirmed by amplification of specific 23S rDNA regions and nuc gene profile with PCR. Results: A total of 235 fish samples were analyzed. A diversity of Enterobacteriaceae and Staphylococcus was detected. Twenty species of Enterobacteriaceae were identified among which, the most frequent were Escherichia coli, Salmonella sp, Raoultella ornithinolytica and Serratia odorifera, respectively in 22.6%, 4.3%, 28.9%, 17.4% of the samples analyzed. However, eleven species of Staphylococcus were identified among which, Staphylococcus xylosus, Staphylococcus aureus, Staphylococcus lugdunensis, and Staphylococcus sciuri were the most frequent with respective percentages of 47.7%, 23.4%, 12.8% and 10.6% of samples. For all the samples, the species frequently isolated were: Raoultella ornithinolytica, Escherichia coli, Serratia odorifera, Staphylococcus aureus, Staphylococcus xylosus, and Staphylococcus lugdunensis. The uidA gene specific to Escherichia coli was detected in 82.85% of strains (29/35). Amplification of the specific 23S rDNA region using staur primers was observed in 98% (49/50) of the isolated Staphylococcus aureus strains and the nuc gene was detected in 86% of Staphylococcus aureus strains. Conclusion: The isolated bacteria are potential pathogens involved in foodborne illnesses and intoxications. Effective sanitary safety systems must be implemented to guarantee the sanitary quality of fish supplied to consumers.展开更多
A Canadian in situ oilsands bitumen-derived vacuum residue(VR)was subjected to supercritical fluid extraction and fractionation(SFEF)into 13 extractable fractions and an unextractable end-cut and characterized by posi...A Canadian in situ oilsands bitumen-derived vacuum residue(VR)was subjected to supercritical fluid extraction and fractionation(SFEF)into 13 extractable fractions and an unextractable end-cut and characterized by positive-and negative-ion electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS).The results of negative-ion ESI FT-ICR MS showed that the N1 class species was the most abundant and the multifunctional group compounds,such as N1 O1,N1 O2,N1 S1,N1 S2,and N2 class species became abundant as the SFEF fraction became heavier.In positive-ion ESI mode,the relative abundance of N1 class species decreased gradually in the heavy SFEF fractions while that of multifunctional group compounds increased.The relative abundance of N4 V1 O1 increased dramatically in heavy fractions and the end-cut.The distributions of polar heteroatom species of VR derived from oilsands bitumen were similar with those of VR derived from the Venezuela Orinoco extra heavy oil.展开更多
Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing infections resulting in severe morbidity and mortality worldwide. To date, the true nature and extent of MRSA infections in the Caribbean ...Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing infections resulting in severe morbidity and mortality worldwide. To date, the true nature and extent of MRSA infections in the Caribbean are not well understood. This is a review of the limited studies in the Caribbean describing the prevalence, epidemiology, and molecular characteristics of MRSA in hospitalized and non-hospitalized patients. Relevant articles were searched and extracted from PubMed and Mendeley and a narrative review of the findings was constructed. An aggregate of 24 articles, from 1999 to 2020, was found from 10 of 27 countries. Majority of the studies were from Trinidad and Tobago (29%) and Jamaica (21%) while 50% were from Barbados, Dominican Republic, Martinique, Haiti, Cuba, St. Kits & Nevis, Guadeloupe, and Guyana. Approximately 75% of investigations were conducted on hospitalized patients versus 20% on outpatients. The data revealed geographical differences in the prevalence of MRSA within the Caribbean;20% - 100% of Staphylococcus aureus clinical isolates from hospitalized patients and outpatients were resistant to methicillin, macrolides, and fluoroquinolones, but susceptible to several non-beta lactam antibiotics, due to the widespread occurrence of CA-MRSA clone ST8 SCCmec IV, PVL positive. There was moderate prevalence of ST72 SCCmec V (14% - 25%) in both hospital and community settings in a few of the countries while ST30 SCCmec IV, PVL positive, was moderately prevalent (27%) only in Dominican Republic. Also, there was moderate prevalence of HA-MRSA ST5 SCCmec II (18%) in community settings in the Dominican Republic and Martinique, but high prevalence of HA-MRSA ST239 SCCmec III (60%) in hospitalized patients in Cuba and Trinidad & Tobago. The epidemiologic profile of MRSA in both hospital and community settings is changing in the Caribbean. Epidemiological studies on outpatient settings and the implementation of stringent hospital infection control measures are needed in the region.展开更多
<i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> is an emerging ubiquitous and opportunistic pathogen that cur...<i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> is an emerging ubiquitous and opportunistic pathogen that currently contaminates a wide spectrum of foods including powdered milk and poses a lethal threat to neonates, the elderly and persons with immune deficiencies. They cause life threatening neonatal meningitis, septicemia, and necrotizing enterocolitis. A total of 360 samples of powdered infant formula were collected from postnatal hospital attendees reconstituting the PIF for their children in the North Central region of Nigeria where cases of infant mortality </span><span style="font-family:Verdana;">are </span><span style="font-family:""><span style="font-family:Verdana;">very high and presenting as enterocolitis and diarrhea. Pre-enriched samples were cultured in chromogenic </span><i><span style="font-family:Verdana;">Cronobacter</span></i><span style="font-family:Verdana;"> broth and were then further sub-cultured into a chromogenic </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> agar. They were positive, exhibiting yellowish cultures typical of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. Biochemical tests of the isolates were also carried out and indicated the presence of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The isolates were then characterized molecularly using specie specific PCR detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The targeted genes of interest were </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene and </span><i><span style="font-family:Verdana;">CPA</span></i><span style="font-family:Verdana;"> gene. The isolates tested showed bands for </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene on electrophoresis imager and were confirmed as </span><i><span style="font-family:Verdana;">Cronobacter sakazakii.</span></i><span style="font-family:Verdana;"> In Nigeria, majority of infants are still fed with PIF. There is no existing data on the detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> previously reported in the North central region of Nigeria hence the need to carry out the present study. The result of the study demonstrated the need for effective prevention and control measures as contamination of PIF with </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> constituted potential public health risk to neonates and infants.展开更多
Wild relatives possess potential genetic diversity for maize (<i><span style="font-family:Verdana;">Zea mays</span></i><span style="font-family:Verdana;"> L.) improvem...Wild relatives possess potential genetic diversity for maize (<i><span style="font-family:Verdana;">Zea mays</span></i><span style="font-family:Verdana;"> L.) improvement. Characterization of maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> introgression lines (ILs) is of great value to diversify the genetic base and improve the maize germplasm. Four maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> IL generations, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> BC1, BC2, BC3, and RIL, were constructed under the elite inbred background of 48-2, elite inbred line that is widely used in maize breeding in Southwestern China, and were phenotyped in different years and genotyped with 56110 SNPs. The results indicated that 48-2 had higher phenotypic performances than all the characterized ILs on most of the agronomic traits. Compared with other ILs, BC2 individuals exhibited more similar performance to 48-2 on most traits and possessed the highest kernel ratio (66.5%). Population structure and principal component analysis indicated that BC3 individuals gathered closer to 48-2 and exhibited the lowest </span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;">-introgression frequency (0.50%), while BC2 (29.06%) and RIL (18.52%) showed higher introgression frequency. The high level of genetic diversity observed in the maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> ILs demonstrated that </span><i><span style="font-family:Verdana;">Z</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">mays</span></i><span style="font-family:Verdana;"> ssp. </span><i><span style="font-family:Verdana;">mexicana </span></i><span style="font-family:Verdana;">can serve as a potential source for the enrichment of maize germplasm.</span>展开更多
Objective To determine the molecular characterization of full-length genome of Japanese encephalitis virus(JEV) genotype V. Methods The full-length nucleotide sequences of JEV strains isolated from different locations...Objective To determine the molecular characterization of full-length genome of Japanese encephalitis virus(JEV) genotype V. Methods The full-length nucleotide sequences of JEV strains isolated from different locations and sources were used in sequence and phylogenetic analysis. Results The full-length genome of genotypes V JEV, XZ0934, and Muar strain were composed of 10 983 and 10 988 nucleotides respectively and shared a lower level of identity with JEV genotypes I-IV, ranging from 78.4%(G I, KV1899) to 79.7%(G III, JaGAr01), for the nucleotide sequences, and from 90.0%(G I, KV1899) to 91.8%(G III, JaGAr01) for the amino acid sequences. The open reading frame(ORF) of JEV genotype V spanned nucleotides 96 to 10 397 and encoded 3 433 amino acids. Interestingly, a comparison with JEV genotype I-IV revealed that 3 nucleotides(encoded with a serine residue) were inserted in the NS4A gene of JEV genotype V, and the insertion of nucleotides was also found in downstream of the ORF stop codon in 3'-untranslated region. Moreover, numerous amino acid mutations were observed in 3 functional domains of the E gene of JEV genotype V. Conclusion The molecular characterization of JEV genotype V is significantly different from that of the known genotypes I-IV. The mutations located in the coding region and the non-coding region may be molecular markers of JEV genotype V and warrant further studies to determine their effects on biology and immunogenicity of genotype V strains.展开更多
Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide: H1N1, H3N2, and H1N2. European avian-like H1N1 viruses, which were initially detected in European pig populations in...Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide: H1N1, H3N2, and H1N2. European avian-like H1N1 viruses, which were initially detected in European pig populations in 1979, have been circulating in pigs in eastern China since 2007. In this study, six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China. Based on whole genome sequencing, molecular characteristics of two isolates were determined. Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations, especially similar to those found in China. Four potential glycosylation sites were observed at positions 13, 26, 198, 277 in the HA1 proteins of the two isolates. Due to the presence of a stop codon at codon 12, the isolates contained truncated PB1-F2 proteins. In this study, the isolates contained 591Q, 627E and 701N in the polymerase subunit PB2, which had been shown to be determinants of virulence and host adaptation. The isolates also had a D rather than E at position 92 of the NS1, a marker of mammalian adaptation. Both isolates contained the GPKV motif at the PDZ ligand domain of the 3' end of the NS1, a characteristic marker of the European avian-like swine viruses since about 1999, which is distinct from those of avian, human and classical swine viruses. The M2 proteins of the isolates have the mutation (S31N), a characteristic marker of the European avian-like swine viruses since about 1987, which may confer resistance to amantadine and rimantadine antivirals. Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs, and raise more concerns about the occurrence of cross-species transmission events.展开更多
Apple necrotic mosaic virus(ApNMV) was identified in crabapple trees with mosaic symptoms from Zaozhuang, Shandong Province, China, by reverse transcription polymerase chain reaction(RT-PCR) analysis. The complete nuc...Apple necrotic mosaic virus(ApNMV) was identified in crabapple trees with mosaic symptoms from Zaozhuang, Shandong Province, China, by reverse transcription polymerase chain reaction(RT-PCR) analysis. The complete nucleotide sequences of one isolate from crabapple(ApNMV-Hai) and two isolates from apple(ApNMV-Hua and-Qu) were determined. The sizes of genomic RNA1, 2 and 3 of the three isolates differed from those of the previously reported isolate ApNMV-P126 from Japanese apple, especially RNA3. Compared with the nucleotide(nt) sequence of RNA3 in isolate P126, those in the Hai and Qu isolates were 7 and 33 nt shorter, respectively, and that of isolate Hua was 7 nt longer. Alignment analyses showed that these differences in size were mainly due to differences in the lengths of the 5′ untranslated region(UTR) and the UTR region between the ORFs encoding the movement protein and the coat protein. In the phylogenetic trees constructed using the full genomic sequences of RNA1, 2 and 3, the isolate Hai clustered into a group with the isolate Qu in the RNA1 tree, but formed an individual branch in the RNA2 and 3 trees. Three recombination events were identified in the nucleotide sequences of RNA1 and 2 among the isolates ApNMV-Hai,-Hua, and-Qu. This is the first report of the full genome sequence of ApNMV in crabapple.展开更多
Forty seven clinical samples of Fowl adenovirus (FAdV) associated with Inclusion Body Hepatitis (IBH) from Peruvian broilers received between July 2006 and April 2013 were genotyped using sequencing of L1 Loop of Hexo...Forty seven clinical samples of Fowl adenovirus (FAdV) associated with Inclusion Body Hepatitis (IBH) from Peruvian broilers received between July 2006 and April 2013 were genotyped using sequencing of L1 Loop of Hexon gene. All 47 clinical samples presented macroscopic and histopathology lesions consistent with IBH, and amplified a specific fragment of Hexon gene by Polymerase Chain Reaction (PCR). A unique nucleotide sequence of 789 base pairs of Hexon gene (position 273 to 1061) was obtained in all 47 clinical samples analyzed. This sequence showed a high level of conservation in amino acid and nucleotide sequence (>99%) with a Fowl Adenovirus C serotype 4 previously identified. Sequence and phylogenetic analysis indicate no genotypic variation in Peruvian isolates. The presence of a unique genotype very closely related with genotype C1 previously reported in Peru and Ecuador (>99%), suggests the presence of FAdV C serotype 4 genotype C1 in clinical cases of IBH from Peruvian broilers.展开更多
Objective: To present the molecular characterization of Cysticercus tenuicollis(C. tenuicollis) of Taenia hydatigena(T. hydatigena) from livestock isolates in Egypt, and to introduce a detailed image of C. tenuicollis...Objective: To present the molecular characterization of Cysticercus tenuicollis(C. tenuicollis) of Taenia hydatigena(T. hydatigena) from livestock isolates in Egypt, and to introduce a detailed image of C. tenuicollis infection in ruminant animals in Upper Egypt.Methods: The prevalence rates of C. tenuicollis infections among the slaughtered animals from different organs were determined using the amplification of sequencing of the MT-CO1 gene.Results: In the present study the infection rates of C. tenuicollis were found to be 16%and 19% in sheep and goat samples respectively. Firstly we report one larval stage of T. hydatigena detected in the camel liver in Egypt. C. tenuicollis infection manifested a higher prevalence in females than in males. Those above two years of age manifested a higher infection rate than younger animals. The preferred site for the infection was the omentum: a 70% preference in sheep and a 68% preference in goats. The molecular characterization using the MT-CO1 gene of isolates from sheep, goats and camels corresponded to T. hydatigena. For this study, molecular characterizations of T. hydatigena were done for the first time in Egypt. Molecular tools are of great assistance in characterizing the C. tenuicollis parasite especially when the morphological character cannot be detected, because the metacestodes are frequently confused with infection by the hydatid cyst, especially when these occur in the visceral organs. In the present study,C. tenuicollis manifested high identity in the goat and sheep samples, while differences were found more frequently in the camel samples(10 base pair).Conclusions: Clearly molecular diagnosis for C. tenuicollis infection significantly helps to differentiate it from such other metacestodes as hydatidosis, which manifests a completely different pathogenicity and requires different control programs.展开更多
Rotavirus gastroenteritis is a major public health concern globally, estimated to cause 215,000 deaths among children < 5 years of age in 2013;with majority of mortality occurring in developing countries. In 2013, ...Rotavirus gastroenteritis is a major public health concern globally, estimated to cause 215,000 deaths among children < 5 years of age in 2013;with majority of mortality occurring in developing countries. In 2013, it was estimated that Nigeria was the second country with the highest number of rotavirus deaths. Monitoring of circulating rotavirus strains in Enugu, Nigeria is part of on-going rotavirus surveillance before the introduction of rotavirus vaccination. A total of 2694 stool samples were collected from enrolled under 5 years old children with diarrhoea between January 2011 and December 2016 and tested the virus using an antigen enzyme immunoassay. Randomly selected rotavirus positive samples were further characterized by rotavirus genotype methods to identify the G and P types circulating during the study period. Rotavirus was detected in 1242 (46%) of the 2694 samples collected over the six years period. Of these, 867 were randomly selected for genotyping. G and P types could be assigned for 832 samples (96%), while 31 (3.6%) could only be assigned either genotype G or P (partially typed) and 4 (0.4%) could not be assigned genotype G and P (untypeable). The most common G-genotypes detected during the entire study period were G12, G1 and G3 accounting for 27.6%, 21.0% and 16.3% respectively. Mixed G and P-genotypes were commonly detected. Ninety-one of the samples, representing 10.8% (91/839) had mixed G-genotype whilst 130 of the samples representing 15.2% (130/852) had mixed P-genotype. The most common P-genotypes detected were P[8], P[6] and P[4] representing 38.3%, 35.4% and 9.1% respectively. The predominant strain detected was G12P[8] (22.3%) followed by G3P[6] (14.5%), G1P[8] (9.2%) and G1P[6] (8.0%). These data are useful for making an informed decision about the introduction of rotavirus vaccine into the national routine immunization program and to monitor the impact of the vaccine post licensure.展开更多
The current study was performed to evaluate the liver function status as well as molecular characterization of the recovered worms in rats experimentally infected with F. hepatica. Sixteen male Wister rats aged 30 day...The current study was performed to evaluate the liver function status as well as molecular characterization of the recovered worms in rats experimentally infected with F. hepatica. Sixteen male Wister rats aged 30 days were randomly allocated into two groups (n = 8). The first group was infected orally with 15 viable encysted metacercaria of F. hepatica per animal. The other group was kept non-infected (control group). At zero time (before infection), the 2<sup>nd</sup>, 4<sup>th</sup>, 6<sup>th</sup>, 8<sup>th</sup>, 10<sup>th</sup>, 12<sup>th</sup> and 14<sup>th</sup> weeks post-infection (WPI), blood and serum samples were collected via puncture of retro-orbital plexus of veins from each rat. Serum enzyme level (AST and ALT) and total protein were measured, and the serum protein profile was carried out using agarose gel electrophoresis. During the period of the experiment, serum ALT and AST activities and serum total globulins significantly increased while serum total proteins and albumin markedly decreased in the infected group. On the 14<sup>th</sup> WPI, the data of the electropherogram showed that globulin fractions (α1-, β- and γ-globulin) levels were significantly increased while α2-globulin was markedly decreased in the infected group. The molecular analysis confirmed the amplification of the ITS1, ITS2 and NDI genes of F. hepatica recovered from the infected liver of rats with amplicon sizes of 630, 510 and 560 bp, respectively. Sequencing of the amplified ITS gene resulted in the determination of 3 strains (PP108836, PP108837, and PP108838). Also, analysis of the ITS2 gene resulted in obtaining 3 isolates under the accession numbers (PP109065, PP109066, and PP109067). In conclusion, fasciolosis in the rat model is suitable for routine experimental infections and caused a pronounced liver dysfunction with discharging of the Fasciola eggs in the faeces and the development of adult stages in the bile ducts. Furthermore, molecular techniques are a sensitive tool for the identification and characterisation of the Fasciola parasite.展开更多
In June 2013,the fi rst human H6N1 infl uenza virus infec-tion was confirmed in Taiwan.However,the origin and molecular characterization of this virus,A/Taiwan/2/2013(H6N1),have not been well studied thus far.In the p...In June 2013,the fi rst human H6N1 infl uenza virus infec-tion was confirmed in Taiwan.However,the origin and molecular characterization of this virus,A/Taiwan/2/2013(H6N1),have not been well studied thus far.In the present report,we performed phylogenetic and coalescent analy-ses of this virus and compared its molecular profi le/char-acteristics with other closely related strains.Molecular characterization of H6N1 revealed that it is a typical avian infl uenza virus of low pathogenicity,which might not rep-licate and propagate well in the upper airway in mammals.Phylogenetic analysis revealed that the virus clusters with A/chicken/Taiwan/A2837/2013(H6N1)in seven genes,except PB1.For the PB1 gene,A/Taiwan/2/2013 was clus-tered with a different H6N1 lineage from A/chicken/Taiwan/A2837/2013.Although a previous study demonstrated that the PB2,PA,and M genes of A/Taiwan/2/2013 might be derived from the H5N2 viruses,coalescent analyses revealed that these H5N2 viruses were derived from more recent strains than that of the ancestor of A/Taiwan/2/2013.Therefore,we propose that A/Taiwan/2/2013 is a reassor-tant from different H6N1 lineages circulating in chickens in Taiwan.Furthermore,compared to avian isolates,a sin-gle P186L(H3 numbering)substitution in the hemaggluti-nin H6 of the human isolate might increase the mammali-an receptor binding and,hence,this strain’s pathogenicity in humans.Overall,human infection with this virus seems an accidental event and is unlikely to cause an infl uenza pandemic.However,its co-circulation and potential reas-sortment with other infl uenza subtypes are still worthy of attention.展开更多
One of the most devastating diseases of rice worldwide is bacterial blight (BLB) caused by Xanthomonas oryzae pv. Oryzae (Xoo). In Benin, Xoo was first described in 2013 on wild rice Oryzae longistaminata. So far, no ...One of the most devastating diseases of rice worldwide is bacterial blight (BLB) caused by Xanthomonas oryzae pv. Oryzae (Xoo). In Benin, Xoo was first described in 2013 on wild rice Oryzae longistaminata. So far, no study has been done on Beninese Xoo strains. We do not know whether the pathogen has already passed into the rice varieties grown, or if they are exposed to other bacteria. Whereas the use of resistant varieties, carrying resistance genes, is the only highly effective and environmentally friendly way to control this disease, no information is available on these Xoo resistance genes in rice varieties grown in Benin apart from the one we recently. This study aims to identify Beninese Xoo strains, causing BLB and screen rice varieties grown in Benin for the main resistance genes. Diseased rice leaves showing typical symptoms of fire blight collected from different rice fields in the three phytogeographic areas of Benin were analyzed by PCR for Xoo-specific sequence identification. Furthermore, seventy-five collected rice accessions were screened to identify xa5, Xa7, xa13, and Xa21 resistance genes to Xoo. The results reveal that Xanthomonas oryzae was identified in two fields in Banikouara and one in Malanville. On the other hand, Sphingomonas sp. has been identified in several other rice fields in Benin. Forty-seven of seventy-five rice accessions examined (62.66%) carried Xoo resistance genes with 3 (4%) and 40 (53.33%) of xa5 and Xa21 respectively. None of the accessions had either Xa7 or xa13 resistance genes. Three accessions possess both xa5 and Xa21 genes. Isogenic lines IRBB60 and IRBB21, supposed to be a positive control, presented a Xoo sensitivity allele. These results indicate that Xoo has moved from the wild rice variety to the cultivated variety in northern Benin and varietal improvement programs must be implemented with varieties having several resistance genes for the efficient response against a possible BLB pandemic in Benin.展开更多
Infectious bursal disease virus(IBDV) poses a significant threat to the poultry industry. Viral protein 2(VP2), the major structural protein of IBDV, has been subjected to frequent mutations that have imparted tremend...Infectious bursal disease virus(IBDV) poses a significant threat to the poultry industry. Viral protein 2(VP2), the major structural protein of IBDV, has been subjected to frequent mutations that have imparted tremendous genetic diversity to the virus. To determine how amino acid mutations may affect the virulence of IBDV, we built a structural model of VP2 of a very virulent strain of IBDV identified in China, vv IBDV Gx, and performed a molecular dynamics simulation of the interaction between virulence sites. The study showed that the amino acid substitutions that distinguish vv IBDV from attenuated IBDV(H253Q and T284A) favor a hydrophobic and flexible conformation of ?-barrel loops in VP2, which could promote interactions between the virus and potential IBDV-specific receptors. Population sequence analysis revealed that the IBDV strains prevalent in East Asia show a significant signal of positive selection at virulence sites 253 and 284. In addition, a signal of co-evolution between sites 253 and 284 was identified. These results suggest that changes in the virulence of IBDV may result from both the interaction and the co-evolution of multiple amino acid substitutions at virulence sites.展开更多
Prothoracicotropic hormone (PTTH), a neuropeptide hormone stimulating the prothoracic glands to synthesize ecdysone, plays an important role in regulating postembryonic development in insects. The cDNA encoding PTTH w...Prothoracicotropic hormone (PTTH), a neuropeptide hormone stimulating the prothoracic glands to synthesize ecdysone, plays an important role in regulating postembryonic development in insects. The cDNA encoding PTTH was isolated and sequenced from the beet armyworm, Spodoptera exigua (Spe). The deduced a?mino acid sequence is composed of a signal peptide, a peptide (65 amino acids) of un-known function, and a mature PTTH molecule (111 amino acids). The Spe-PTTH shows similarities (45.5%―70.3%) to other known PTTHs reported in Lepidoptera species, but 7 cysteine r?esidues and the hydrophobic regions were conserved. Whole-mount immunocytochemistry by using an antiserum against recombinant Helicoverpa armigera PTTH showed that Spe-PTTH was synthesized in two pairs of neurosecretory cells in the S. exigua brain. Northern blot analysis demonstrates the presence of a 1.2-kb transcript in the brain. The Spe-PTTH mRNA is detectable at high levels at the wandering larval stage, early pupal stage, and pharate adult stage, suggesting that the Spe-PTTH gene might be corre-lated with molting, metamorphosis, and reproduction.展开更多
The inclusion complexes of poorly water-soluble cephalosporin, cefuroxime axetil(CFA), were prepared with β-cyclodextrin(βCD) with or without addition of L-arginine(ARG) to improve its physicochemical properties. We...The inclusion complexes of poorly water-soluble cephalosporin, cefuroxime axetil(CFA), were prepared with β-cyclodextrin(βCD) with or without addition of L-arginine(ARG) to improve its physicochemical properties. We also investigated the effect of ARG on complexation efficiency(CE) of βCD towards CFA in an aqueous medium through phase solubility behaviour according to Higuchi and Connors. Although phase solubility studies showed AL(linear) type of solubility curve in presence and absence of ARG, the CE and association constant(Ks) of βCD towards CFA were significantly promoted in presence of ARG,justifying its use as a ternary component. The solid systems of CFA with βCD were obtained by spray drying technique with or without incorporation of ARG and characterized by differential scanning calorimetry(DSC), X-ray powder diffractometry(XRPD), scanning electron microscopy(SEM), and saturation solubility and dissolution studies. The molecular modeling studies provided a better insight into geometry and inclusion mode of CFA inside βCD cavity. The solubility and dissolution rate of CFA were significantly improved upon complexation with βCD as compared to CFA alone. However, ternary system incorporated with ARG performed better than binary system in physicochemical evaluation. In conclusion, ARG could be exploited as a ternary component to improve the physicochemical properties of CFA via βCD complexation.展开更多
Subtypes of H1N1 influenza virus can be found in humans in North America,while they are also asso-ciated with the infection of swine.Characterization of the genotypes of viral strains in human popula-tions is importan...Subtypes of H1N1 influenza virus can be found in humans in North America,while they are also asso-ciated with the infection of swine.Characterization of the genotypes of viral strains in human popula-tions is important to understand the source and distribution of viral strains.Genomic and protein sequences of 10 isolates of the 2009 outbreak ofinfluenza A(H1N1) virus in North America were obtained from GenBank database.To characterize the genotypes of these viruses,phylogenetic trees of genes PB2,PB1,PA,HA,NP,NA,NS and M were constructed by Phylip3.67 program and N-Linked glycosylation sites of HA,NA,PB2,NS1 and M2 proteins were analyzed online by NetNGlyc1.0 program.Phylogenetic analysis indicated that these isolates are virtually identical but may be recombinant viruses because their genomic fragments come from different viruses.The isolates also contain a char-acteristic lowly pathogenic amino acid motif at their HA cleavage sites(IPSIQSR↓GL),and an E residue at position 627 of the PB2 protein which shows its high affinity to humans.The homologous model of M proteins showed that the viruses had obtained the ability of anti-amantadine due to the mutation at the drug-sensitive site,while sequence analysis of NA proteins indicated that the viruses are still suscep-tible to the neuraminidase inhibitor drug(i.e.oseltamivir and zanamivir) because no mutations have been observed.Our results strongly suggested that the viruses responsible for the 2009 outbreaks ofinfluenza A(H1N1) virus have the ability to cross species barriers to infect human and mammalian animals based on molecular analysis.These findings may further facilitate the therapy and prevention of possible transmission from North America to other countries.展开更多
文摘Background: To preserve its nutritional properties, fish must have good sanitary quality. The objective of this study was to investigate some pathogens contaminating smoked, dried, and braised fish marketed in Ouagadougou. Methodology: Potential pathogens of Enterobacteriaceae and Staphylococcus were screened in eight (8) species of processed fish. The investigation of the germs was carried out following the normative methods of microbiology. The identities of the strains were determined by API 20 E (BioMerieux S.A., France) and API STAPH (BioMerieux S.A., France) kits for Enterobacteriaceae and Staphylococcus species respectively. The uidA gene profile in Escherichia coli isolates was determined by simplex PCR. The identity of Staphylococcus aureus was confirmed by amplification of specific 23S rDNA regions and nuc gene profile with PCR. Results: A total of 235 fish samples were analyzed. A diversity of Enterobacteriaceae and Staphylococcus was detected. Twenty species of Enterobacteriaceae were identified among which, the most frequent were Escherichia coli, Salmonella sp, Raoultella ornithinolytica and Serratia odorifera, respectively in 22.6%, 4.3%, 28.9%, 17.4% of the samples analyzed. However, eleven species of Staphylococcus were identified among which, Staphylococcus xylosus, Staphylococcus aureus, Staphylococcus lugdunensis, and Staphylococcus sciuri were the most frequent with respective percentages of 47.7%, 23.4%, 12.8% and 10.6% of samples. For all the samples, the species frequently isolated were: Raoultella ornithinolytica, Escherichia coli, Serratia odorifera, Staphylococcus aureus, Staphylococcus xylosus, and Staphylococcus lugdunensis. The uidA gene specific to Escherichia coli was detected in 82.85% of strains (29/35). Amplification of the specific 23S rDNA region using staur primers was observed in 98% (49/50) of the isolated Staphylococcus aureus strains and the nuc gene was detected in 86% of Staphylococcus aureus strains. Conclusion: The isolated bacteria are potential pathogens involved in foodborne illnesses and intoxications. Effective sanitary safety systems must be implemented to guarantee the sanitary quality of fish supplied to consumers.
文摘A Canadian in situ oilsands bitumen-derived vacuum residue(VR)was subjected to supercritical fluid extraction and fractionation(SFEF)into 13 extractable fractions and an unextractable end-cut and characterized by positive-and negative-ion electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS).The results of negative-ion ESI FT-ICR MS showed that the N1 class species was the most abundant and the multifunctional group compounds,such as N1 O1,N1 O2,N1 S1,N1 S2,and N2 class species became abundant as the SFEF fraction became heavier.In positive-ion ESI mode,the relative abundance of N1 class species decreased gradually in the heavy SFEF fractions while that of multifunctional group compounds increased.The relative abundance of N4 V1 O1 increased dramatically in heavy fractions and the end-cut.The distributions of polar heteroatom species of VR derived from oilsands bitumen were similar with those of VR derived from the Venezuela Orinoco extra heavy oil.
文摘Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing infections resulting in severe morbidity and mortality worldwide. To date, the true nature and extent of MRSA infections in the Caribbean are not well understood. This is a review of the limited studies in the Caribbean describing the prevalence, epidemiology, and molecular characteristics of MRSA in hospitalized and non-hospitalized patients. Relevant articles were searched and extracted from PubMed and Mendeley and a narrative review of the findings was constructed. An aggregate of 24 articles, from 1999 to 2020, was found from 10 of 27 countries. Majority of the studies were from Trinidad and Tobago (29%) and Jamaica (21%) while 50% were from Barbados, Dominican Republic, Martinique, Haiti, Cuba, St. Kits & Nevis, Guadeloupe, and Guyana. Approximately 75% of investigations were conducted on hospitalized patients versus 20% on outpatients. The data revealed geographical differences in the prevalence of MRSA within the Caribbean;20% - 100% of Staphylococcus aureus clinical isolates from hospitalized patients and outpatients were resistant to methicillin, macrolides, and fluoroquinolones, but susceptible to several non-beta lactam antibiotics, due to the widespread occurrence of CA-MRSA clone ST8 SCCmec IV, PVL positive. There was moderate prevalence of ST72 SCCmec V (14% - 25%) in both hospital and community settings in a few of the countries while ST30 SCCmec IV, PVL positive, was moderately prevalent (27%) only in Dominican Republic. Also, there was moderate prevalence of HA-MRSA ST5 SCCmec II (18%) in community settings in the Dominican Republic and Martinique, but high prevalence of HA-MRSA ST239 SCCmec III (60%) in hospitalized patients in Cuba and Trinidad & Tobago. The epidemiologic profile of MRSA in both hospital and community settings is changing in the Caribbean. Epidemiological studies on outpatient settings and the implementation of stringent hospital infection control measures are needed in the region.
文摘<i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> is an emerging ubiquitous and opportunistic pathogen that currently contaminates a wide spectrum of foods including powdered milk and poses a lethal threat to neonates, the elderly and persons with immune deficiencies. They cause life threatening neonatal meningitis, septicemia, and necrotizing enterocolitis. A total of 360 samples of powdered infant formula were collected from postnatal hospital attendees reconstituting the PIF for their children in the North Central region of Nigeria where cases of infant mortality </span><span style="font-family:Verdana;">are </span><span style="font-family:""><span style="font-family:Verdana;">very high and presenting as enterocolitis and diarrhea. Pre-enriched samples were cultured in chromogenic </span><i><span style="font-family:Verdana;">Cronobacter</span></i><span style="font-family:Verdana;"> broth and were then further sub-cultured into a chromogenic </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> agar. They were positive, exhibiting yellowish cultures typical of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. Biochemical tests of the isolates were also carried out and indicated the presence of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The isolates were then characterized molecularly using specie specific PCR detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The targeted genes of interest were </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene and </span><i><span style="font-family:Verdana;">CPA</span></i><span style="font-family:Verdana;"> gene. The isolates tested showed bands for </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene on electrophoresis imager and were confirmed as </span><i><span style="font-family:Verdana;">Cronobacter sakazakii.</span></i><span style="font-family:Verdana;"> In Nigeria, majority of infants are still fed with PIF. There is no existing data on the detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> previously reported in the North central region of Nigeria hence the need to carry out the present study. The result of the study demonstrated the need for effective prevention and control measures as contamination of PIF with </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> constituted potential public health risk to neonates and infants.
文摘Wild relatives possess potential genetic diversity for maize (<i><span style="font-family:Verdana;">Zea mays</span></i><span style="font-family:Verdana;"> L.) improvement. Characterization of maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> introgression lines (ILs) is of great value to diversify the genetic base and improve the maize germplasm. Four maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> IL generations, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> BC1, BC2, BC3, and RIL, were constructed under the elite inbred background of 48-2, elite inbred line that is widely used in maize breeding in Southwestern China, and were phenotyped in different years and genotyped with 56110 SNPs. The results indicated that 48-2 had higher phenotypic performances than all the characterized ILs on most of the agronomic traits. Compared with other ILs, BC2 individuals exhibited more similar performance to 48-2 on most traits and possessed the highest kernel ratio (66.5%). Population structure and principal component analysis indicated that BC3 individuals gathered closer to 48-2 and exhibited the lowest </span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;">-introgression frequency (0.50%), while BC2 (29.06%) and RIL (18.52%) showed higher introgression frequency. The high level of genetic diversity observed in the maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> ILs demonstrated that </span><i><span style="font-family:Verdana;">Z</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">mays</span></i><span style="font-family:Verdana;"> ssp. </span><i><span style="font-family:Verdana;">mexicana </span></i><span style="font-family:Verdana;">can serve as a potential source for the enrichment of maize germplasm.</span>
基金supported by grants from the Ministry of Science and Technology,China(2011CB504702)National Natural Science Foundation of China(81290342)Development Grant of State Key Laboratory for Infectious Disease Prevention and Control(2008SKLID105)
文摘Objective To determine the molecular characterization of full-length genome of Japanese encephalitis virus(JEV) genotype V. Methods The full-length nucleotide sequences of JEV strains isolated from different locations and sources were used in sequence and phylogenetic analysis. Results The full-length genome of genotypes V JEV, XZ0934, and Muar strain were composed of 10 983 and 10 988 nucleotides respectively and shared a lower level of identity with JEV genotypes I-IV, ranging from 78.4%(G I, KV1899) to 79.7%(G III, JaGAr01), for the nucleotide sequences, and from 90.0%(G I, KV1899) to 91.8%(G III, JaGAr01) for the amino acid sequences. The open reading frame(ORF) of JEV genotype V spanned nucleotides 96 to 10 397 and encoded 3 433 amino acids. Interestingly, a comparison with JEV genotype I-IV revealed that 3 nucleotides(encoded with a serine residue) were inserted in the NS4A gene of JEV genotype V, and the insertion of nucleotides was also found in downstream of the ORF stop codon in 3'-untranslated region. Moreover, numerous amino acid mutations were observed in 3 functional domains of the E gene of JEV genotype V. Conclusion The molecular characterization of JEV genotype V is significantly different from that of the known genotypes I-IV. The mutations located in the coding region and the non-coding region may be molecular markers of JEV genotype V and warrant further studies to determine their effects on biology and immunogenicity of genotype V strains.
基金Supported by the Natural Science Foundation of Jiangsu Province(BK2009434)the Innovation Platform for Public Health Emergency Preparedness and Response(NO.ZX201109)the Key Medical Talent Foundation of Jiangsu Province(RC2011084)
文摘Currently, three predominant subtypes of influenza virus are prevalent in pig populations worldwide: H1N1, H3N2, and H1N2. European avian-like H1N1 viruses, which were initially detected in European pig populations in 1979, have been circulating in pigs in eastern China since 2007. In this study, six influenza A viruses were isolated from 60 swine lung samples collected from January to April 2011 in eastern China. Based on whole genome sequencing, molecular characteristics of two isolates were determined. Phylogenetic analysis showed the eight genes of the two isolates were closely related to those of the avian-like H1N1 viruses circulating in pig populations, especially similar to those found in China. Four potential glycosylation sites were observed at positions 13, 26, 198, 277 in the HA1 proteins of the two isolates. Due to the presence of a stop codon at codon 12, the isolates contained truncated PB1-F2 proteins. In this study, the isolates contained 591Q, 627E and 701N in the polymerase subunit PB2, which had been shown to be determinants of virulence and host adaptation. The isolates also had a D rather than E at position 92 of the NS1, a marker of mammalian adaptation. Both isolates contained the GPKV motif at the PDZ ligand domain of the 3' end of the NS1, a characteristic marker of the European avian-like swine viruses since about 1999, which is distinct from those of avian, human and classical swine viruses. The M2 proteins of the isolates have the mutation (S31N), a characteristic marker of the European avian-like swine viruses since about 1987, which may confer resistance to amantadine and rimantadine antivirals. Our findings further emphasize the importance of surveillance on the genetic diversity of influenza A viruses in pigs, and raise more concerns about the occurrence of cross-species transmission events.
基金funded by the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences (CAAS-ASTIP)
文摘Apple necrotic mosaic virus(ApNMV) was identified in crabapple trees with mosaic symptoms from Zaozhuang, Shandong Province, China, by reverse transcription polymerase chain reaction(RT-PCR) analysis. The complete nucleotide sequences of one isolate from crabapple(ApNMV-Hai) and two isolates from apple(ApNMV-Hua and-Qu) were determined. The sizes of genomic RNA1, 2 and 3 of the three isolates differed from those of the previously reported isolate ApNMV-P126 from Japanese apple, especially RNA3. Compared with the nucleotide(nt) sequence of RNA3 in isolate P126, those in the Hai and Qu isolates were 7 and 33 nt shorter, respectively, and that of isolate Hua was 7 nt longer. Alignment analyses showed that these differences in size were mainly due to differences in the lengths of the 5′ untranslated region(UTR) and the UTR region between the ORFs encoding the movement protein and the coat protein. In the phylogenetic trees constructed using the full genomic sequences of RNA1, 2 and 3, the isolate Hai clustered into a group with the isolate Qu in the RNA1 tree, but formed an individual branch in the RNA2 and 3 trees. Three recombination events were identified in the nucleotide sequences of RNA1 and 2 among the isolates ApNMV-Hai,-Hua, and-Qu. This is the first report of the full genome sequence of ApNMV in crabapple.
文摘Forty seven clinical samples of Fowl adenovirus (FAdV) associated with Inclusion Body Hepatitis (IBH) from Peruvian broilers received between July 2006 and April 2013 were genotyped using sequencing of L1 Loop of Hexon gene. All 47 clinical samples presented macroscopic and histopathology lesions consistent with IBH, and amplified a specific fragment of Hexon gene by Polymerase Chain Reaction (PCR). A unique nucleotide sequence of 789 base pairs of Hexon gene (position 273 to 1061) was obtained in all 47 clinical samples analyzed. This sequence showed a high level of conservation in amino acid and nucleotide sequence (>99%) with a Fowl Adenovirus C serotype 4 previously identified. Sequence and phylogenetic analysis indicate no genotypic variation in Peruvian isolates. The presence of a unique genotype very closely related with genotype C1 previously reported in Peru and Ecuador (>99%), suggests the presence of FAdV C serotype 4 genotype C1 in clinical cases of IBH from Peruvian broilers.
文摘Objective: To present the molecular characterization of Cysticercus tenuicollis(C. tenuicollis) of Taenia hydatigena(T. hydatigena) from livestock isolates in Egypt, and to introduce a detailed image of C. tenuicollis infection in ruminant animals in Upper Egypt.Methods: The prevalence rates of C. tenuicollis infections among the slaughtered animals from different organs were determined using the amplification of sequencing of the MT-CO1 gene.Results: In the present study the infection rates of C. tenuicollis were found to be 16%and 19% in sheep and goat samples respectively. Firstly we report one larval stage of T. hydatigena detected in the camel liver in Egypt. C. tenuicollis infection manifested a higher prevalence in females than in males. Those above two years of age manifested a higher infection rate than younger animals. The preferred site for the infection was the omentum: a 70% preference in sheep and a 68% preference in goats. The molecular characterization using the MT-CO1 gene of isolates from sheep, goats and camels corresponded to T. hydatigena. For this study, molecular characterizations of T. hydatigena were done for the first time in Egypt. Molecular tools are of great assistance in characterizing the C. tenuicollis parasite especially when the morphological character cannot be detected, because the metacestodes are frequently confused with infection by the hydatid cyst, especially when these occur in the visceral organs. In the present study,C. tenuicollis manifested high identity in the goat and sheep samples, while differences were found more frequently in the camel samples(10 base pair).Conclusions: Clearly molecular diagnosis for C. tenuicollis infection significantly helps to differentiate it from such other metacestodes as hydatidosis, which manifests a completely different pathogenicity and requires different control programs.
文摘Rotavirus gastroenteritis is a major public health concern globally, estimated to cause 215,000 deaths among children < 5 years of age in 2013;with majority of mortality occurring in developing countries. In 2013, it was estimated that Nigeria was the second country with the highest number of rotavirus deaths. Monitoring of circulating rotavirus strains in Enugu, Nigeria is part of on-going rotavirus surveillance before the introduction of rotavirus vaccination. A total of 2694 stool samples were collected from enrolled under 5 years old children with diarrhoea between January 2011 and December 2016 and tested the virus using an antigen enzyme immunoassay. Randomly selected rotavirus positive samples were further characterized by rotavirus genotype methods to identify the G and P types circulating during the study period. Rotavirus was detected in 1242 (46%) of the 2694 samples collected over the six years period. Of these, 867 were randomly selected for genotyping. G and P types could be assigned for 832 samples (96%), while 31 (3.6%) could only be assigned either genotype G or P (partially typed) and 4 (0.4%) could not be assigned genotype G and P (untypeable). The most common G-genotypes detected during the entire study period were G12, G1 and G3 accounting for 27.6%, 21.0% and 16.3% respectively. Mixed G and P-genotypes were commonly detected. Ninety-one of the samples, representing 10.8% (91/839) had mixed G-genotype whilst 130 of the samples representing 15.2% (130/852) had mixed P-genotype. The most common P-genotypes detected were P[8], P[6] and P[4] representing 38.3%, 35.4% and 9.1% respectively. The predominant strain detected was G12P[8] (22.3%) followed by G3P[6] (14.5%), G1P[8] (9.2%) and G1P[6] (8.0%). These data are useful for making an informed decision about the introduction of rotavirus vaccine into the national routine immunization program and to monitor the impact of the vaccine post licensure.
文摘The current study was performed to evaluate the liver function status as well as molecular characterization of the recovered worms in rats experimentally infected with F. hepatica. Sixteen male Wister rats aged 30 days were randomly allocated into two groups (n = 8). The first group was infected orally with 15 viable encysted metacercaria of F. hepatica per animal. The other group was kept non-infected (control group). At zero time (before infection), the 2<sup>nd</sup>, 4<sup>th</sup>, 6<sup>th</sup>, 8<sup>th</sup>, 10<sup>th</sup>, 12<sup>th</sup> and 14<sup>th</sup> weeks post-infection (WPI), blood and serum samples were collected via puncture of retro-orbital plexus of veins from each rat. Serum enzyme level (AST and ALT) and total protein were measured, and the serum protein profile was carried out using agarose gel electrophoresis. During the period of the experiment, serum ALT and AST activities and serum total globulins significantly increased while serum total proteins and albumin markedly decreased in the infected group. On the 14<sup>th</sup> WPI, the data of the electropherogram showed that globulin fractions (α1-, β- and γ-globulin) levels were significantly increased while α2-globulin was markedly decreased in the infected group. The molecular analysis confirmed the amplification of the ITS1, ITS2 and NDI genes of F. hepatica recovered from the infected liver of rats with amplicon sizes of 630, 510 and 560 bp, respectively. Sequencing of the amplified ITS gene resulted in the determination of 3 strains (PP108836, PP108837, and PP108838). Also, analysis of the ITS2 gene resulted in obtaining 3 isolates under the accession numbers (PP109065, PP109066, and PP109067). In conclusion, fasciolosis in the rat model is suitable for routine experimental infections and caused a pronounced liver dysfunction with discharging of the Fasciola eggs in the faeces and the development of adult stages in the bile ducts. Furthermore, molecular techniques are a sensitive tool for the identification and characterisation of the Fasciola parasite.
基金the National Basic Research Pro-gram(973 Program)(Nos.2010CB530303,2011CB504703,and 2012CB955501an intramural special grant for influenza virus research from the Chinese Academy of Sciences(KSZD-EW-Z-002)the Doctoral Starting up Foundation of Taishan Medical College.GFG is a leading principal investigator of the Innova-tive Research Group of the National Natural Science Foundation of China(Grant No.81021003)。
文摘In June 2013,the fi rst human H6N1 infl uenza virus infec-tion was confirmed in Taiwan.However,the origin and molecular characterization of this virus,A/Taiwan/2/2013(H6N1),have not been well studied thus far.In the present report,we performed phylogenetic and coalescent analy-ses of this virus and compared its molecular profi le/char-acteristics with other closely related strains.Molecular characterization of H6N1 revealed that it is a typical avian infl uenza virus of low pathogenicity,which might not rep-licate and propagate well in the upper airway in mammals.Phylogenetic analysis revealed that the virus clusters with A/chicken/Taiwan/A2837/2013(H6N1)in seven genes,except PB1.For the PB1 gene,A/Taiwan/2/2013 was clus-tered with a different H6N1 lineage from A/chicken/Taiwan/A2837/2013.Although a previous study demonstrated that the PB2,PA,and M genes of A/Taiwan/2/2013 might be derived from the H5N2 viruses,coalescent analyses revealed that these H5N2 viruses were derived from more recent strains than that of the ancestor of A/Taiwan/2/2013.Therefore,we propose that A/Taiwan/2/2013 is a reassor-tant from different H6N1 lineages circulating in chickens in Taiwan.Furthermore,compared to avian isolates,a sin-gle P186L(H3 numbering)substitution in the hemaggluti-nin H6 of the human isolate might increase the mammali-an receptor binding and,hence,this strain’s pathogenicity in humans.Overall,human infection with this virus seems an accidental event and is unlikely to cause an infl uenza pandemic.However,its co-circulation and potential reas-sortment with other infl uenza subtypes are still worthy of attention.
文摘One of the most devastating diseases of rice worldwide is bacterial blight (BLB) caused by Xanthomonas oryzae pv. Oryzae (Xoo). In Benin, Xoo was first described in 2013 on wild rice Oryzae longistaminata. So far, no study has been done on Beninese Xoo strains. We do not know whether the pathogen has already passed into the rice varieties grown, or if they are exposed to other bacteria. Whereas the use of resistant varieties, carrying resistance genes, is the only highly effective and environmentally friendly way to control this disease, no information is available on these Xoo resistance genes in rice varieties grown in Benin apart from the one we recently. This study aims to identify Beninese Xoo strains, causing BLB and screen rice varieties grown in Benin for the main resistance genes. Diseased rice leaves showing typical symptoms of fire blight collected from different rice fields in the three phytogeographic areas of Benin were analyzed by PCR for Xoo-specific sequence identification. Furthermore, seventy-five collected rice accessions were screened to identify xa5, Xa7, xa13, and Xa21 resistance genes to Xoo. The results reveal that Xanthomonas oryzae was identified in two fields in Banikouara and one in Malanville. On the other hand, Sphingomonas sp. has been identified in several other rice fields in Benin. Forty-seven of seventy-five rice accessions examined (62.66%) carried Xoo resistance genes with 3 (4%) and 40 (53.33%) of xa5 and Xa21 respectively. None of the accessions had either Xa7 or xa13 resistance genes. Three accessions possess both xa5 and Xa21 genes. Isogenic lines IRBB60 and IRBB21, supposed to be a positive control, presented a Xoo sensitivity allele. These results indicate that Xoo has moved from the wild rice variety to the cultivated variety in northern Benin and varietal improvement programs must be implemented with varieties having several resistance genes for the efficient response against a possible BLB pandemic in Benin.
基金supported by the National Natural Science Foundation of China(31230018,31430087)the National Science and Technology Major Project for infectious disease of China(2013ZX10004606)
文摘Infectious bursal disease virus(IBDV) poses a significant threat to the poultry industry. Viral protein 2(VP2), the major structural protein of IBDV, has been subjected to frequent mutations that have imparted tremendous genetic diversity to the virus. To determine how amino acid mutations may affect the virulence of IBDV, we built a structural model of VP2 of a very virulent strain of IBDV identified in China, vv IBDV Gx, and performed a molecular dynamics simulation of the interaction between virulence sites. The study showed that the amino acid substitutions that distinguish vv IBDV from attenuated IBDV(H253Q and T284A) favor a hydrophobic and flexible conformation of ?-barrel loops in VP2, which could promote interactions between the virus and potential IBDV-specific receptors. Population sequence analysis revealed that the IBDV strains prevalent in East Asia show a significant signal of positive selection at virulence sites 253 and 284. In addition, a signal of co-evolution between sites 253 and 284 was identified. These results suggest that changes in the virulence of IBDV may result from both the interaction and the co-evolution of multiple amino acid substitutions at virulence sites.
基金We thank the staff in the Beijing READ BIO Bioinformatic Technology Company for their assistance in the phylogenetic inference and bioinformatic analysis of brown planthopper CRY proteins. This research was supported by the Key Program of National Natural Science of China (51037006), the National Basic Research Program of China "973" (2010CB126200) and the National Nature Science Foundations of China (31170362, 31272051, 31470454 and 31070755).
基金Supported by the National Basic Research Program of the Ministry of Science and Technology, People’s Republic of China (Grant No. 2006CB102001)The nucleotide sequence data reported in this article have been submitted to Gen-Bank and have been assigned the accession number AY628763
文摘Prothoracicotropic hormone (PTTH), a neuropeptide hormone stimulating the prothoracic glands to synthesize ecdysone, plays an important role in regulating postembryonic development in insects. The cDNA encoding PTTH was isolated and sequenced from the beet armyworm, Spodoptera exigua (Spe). The deduced a?mino acid sequence is composed of a signal peptide, a peptide (65 amino acids) of un-known function, and a mature PTTH molecule (111 amino acids). The Spe-PTTH shows similarities (45.5%―70.3%) to other known PTTHs reported in Lepidoptera species, but 7 cysteine r?esidues and the hydrophobic regions were conserved. Whole-mount immunocytochemistry by using an antiserum against recombinant Helicoverpa armigera PTTH showed that Spe-PTTH was synthesized in two pairs of neurosecretory cells in the S. exigua brain. Northern blot analysis demonstrates the presence of a 1.2-kb transcript in the brain. The Spe-PTTH mRNA is detectable at high levels at the wandering larval stage, early pupal stage, and pharate adult stage, suggesting that the Spe-PTTH gene might be corre-lated with molting, metamorphosis, and reproduction.
文摘The inclusion complexes of poorly water-soluble cephalosporin, cefuroxime axetil(CFA), were prepared with β-cyclodextrin(βCD) with or without addition of L-arginine(ARG) to improve its physicochemical properties. We also investigated the effect of ARG on complexation efficiency(CE) of βCD towards CFA in an aqueous medium through phase solubility behaviour according to Higuchi and Connors. Although phase solubility studies showed AL(linear) type of solubility curve in presence and absence of ARG, the CE and association constant(Ks) of βCD towards CFA were significantly promoted in presence of ARG,justifying its use as a ternary component. The solid systems of CFA with βCD were obtained by spray drying technique with or without incorporation of ARG and characterized by differential scanning calorimetry(DSC), X-ray powder diffractometry(XRPD), scanning electron microscopy(SEM), and saturation solubility and dissolution studies. The molecular modeling studies provided a better insight into geometry and inclusion mode of CFA inside βCD cavity. The solubility and dissolution rate of CFA were significantly improved upon complexation with βCD as compared to CFA alone. However, ternary system incorporated with ARG performed better than binary system in physicochemical evaluation. In conclusion, ARG could be exploited as a ternary component to improve the physicochemical properties of CFA via βCD complexation.
基金Supported by the National Key Basic Research and Development Program of China (Grant No.2007BC109103)Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No.KSCX2-YW-N-063)National Natural Science Foundation of China (Grant No.30671576)
文摘Subtypes of H1N1 influenza virus can be found in humans in North America,while they are also asso-ciated with the infection of swine.Characterization of the genotypes of viral strains in human popula-tions is important to understand the source and distribution of viral strains.Genomic and protein sequences of 10 isolates of the 2009 outbreak ofinfluenza A(H1N1) virus in North America were obtained from GenBank database.To characterize the genotypes of these viruses,phylogenetic trees of genes PB2,PB1,PA,HA,NP,NA,NS and M were constructed by Phylip3.67 program and N-Linked glycosylation sites of HA,NA,PB2,NS1 and M2 proteins were analyzed online by NetNGlyc1.0 program.Phylogenetic analysis indicated that these isolates are virtually identical but may be recombinant viruses because their genomic fragments come from different viruses.The isolates also contain a char-acteristic lowly pathogenic amino acid motif at their HA cleavage sites(IPSIQSR↓GL),and an E residue at position 627 of the PB2 protein which shows its high affinity to humans.The homologous model of M proteins showed that the viruses had obtained the ability of anti-amantadine due to the mutation at the drug-sensitive site,while sequence analysis of NA proteins indicated that the viruses are still suscep-tible to the neuraminidase inhibitor drug(i.e.oseltamivir and zanamivir) because no mutations have been observed.Our results strongly suggested that the viruses responsible for the 2009 outbreaks ofinfluenza A(H1N1) virus have the ability to cross species barriers to infect human and mammalian animals based on molecular analysis.These findings may further facilitate the therapy and prevention of possible transmission from North America to other countries.