Bioactivity profile of dissolved organic matter and its relation to molecular composition

Dissolved organic matter(DOM)occupies a huge and uncharted molecular space.Given its properties,DOM can be presented as a promising biotechnological resource.However,research into bioactivities of DOM is still in early stages.In this study,the biotechnological potential of terrestrial and marine DOM,its molecular composition and their relationships are investigated.Samples were screened for their in vitro antibacterial,antifungal,anticancer and antioxidant activities.Antibacterial activity was detected against Staphylococcus aureus in almost all DOM samples,with freshwater DOM showing the lowest IC50 values.Most samples also inhibited Staphylococcus epidermidis,and four DOM extracts showed up to fourfold higher potency than the reference drug.Antifungal activity was limited to only porewater DOM towards human dermatophyte Trichophyton rubrum.No significant in vitro anticancer activity was observed.Low antioxidant potential was exerted.The molecular characterization by FT-ICR MS allowed a broad compositional overview.Three main distinguished groups have been identified by PCoA analyses.Antibacterial activities are related to high aromaticity content and highly-unsaturated molecular formulae(O-poor).Antifungal effect is correlated with highly-unsaturated molecular formulae(O-rich).Antioxidant activity is positively related to the presence of double bonds and polyphenols.This study evidenced for the first time antibacterial and antifungal activity in DOM with potential applications in cosmeceutical,pharmaceutical and aquaculture industry.The lack of cytotoxicity and the almost unlimited presence of this organic material may open new avenues in future marine bioprospect-ing efforts.

Assessment of Genetic Diversity in Nepalese Populations of <i>Swertia chirayita</i>(Roxb. Ex Fleming) H. Karst Using RAPD-PCR Technique

Owing to the high demand, Swertia chirayita populations in the wild are being depleted beyond its regeneration capacity. S. chirayita is one of the most valuable medicinal plants of Nepal in trade. Present Molecular investigation was undertaken to understand the level of genetic diversity in five S. chirayita populations of Nepal using Polymerase Chain Reaction (PCR)-based Random amplified polymorphic DNA (RAPD) technique. Thirty four accessions of S. chirayita along with six outlier accessions were analyzed using 26 arbitrary primers. Of the total 285 amplified bands scored for S. chirayita, 263 bands (92.28%) were polymorphic. Two major clusters were revealed in the phenogram generated from cluster analysis using NTSYS-PC software (version 2.21i) for the geographic populations under study. Principal Coordinate Analysis further substantiated the results of the phenograms. Swertia chirayita populations from Sankhuwasabha and Terathum were found to be genetically closest (68%, similar) whilst Nagarjun and Terathum were found to be most distant (33%, similar).The high genetic polymorphism reflected in S. chirayita populations indicates the good survival potentiality and adaptability in changing environmental scenario. The results thus produced might be helpful to plant breeders for elite cultivar development. The RAPD-PCR technique is found to be the rapid and effective tool for genetic diversity assessment in S. chirayita populations and generated insights for the formulation of conservation strategy of this vulnerable species together with its phytochemical distinctiveness.

Cell fusion in the pathogenesis of COVID-19

Dear Editor,Infectionw ithsevereacuterespirator ysy ndrome coronavirus2(SARS-CoV-2),whichcausescoronavirus disease 2019 (COVID-19),is initiated by the virus spike (S)glycoprotein binding to its cellular receptor such as angiotensin converting enzyme 2 (ACE2)[1,2].Subsequently,the virus may take two routes for its entry into the host cells,including an endocytic route that ends up in endosomal compartment,and a plasma membrane route on the cell surface.In both routes,fusion between the viral and plasma membrane was required to introduce the viral genome into the cytoplasm[3].Similarly,SARS-CoV-2 infection results in the expression of fusogenic S glycoprotein on the host cell membrane.

Genetic Diversity of the Palestinian Fig (<i>Ficus carica</i>L.) Collection by Pomological Traits and RAPD Markers

Analysis of differentiation (genetic diversity and related relationships) among 22 landrace (Ficus carica L. sativa) and 2 wild form (F. carica L. caprificus) accessions of fig growing under the same environmental conditions in the Palestinian Fig Collection, Til, Nablus, Palestine, using PCR-based Random Amplified Polymorphic DNA (RAPD) and pomological markers, revealed considerable genetic diversity. The phenotypic analysis shows that pomological traits were permitted to evaluate morphological variability of fig landraces. The Jaccard similarity coefficient between landraces was determined by cluster analysis using the UPGMA method. Based on the genetic relationships among genotypes as illustrated by the dendrograms, generated from pomological and RAPD data by UPGMA clustering method, the following 12 genotypes: Qaisi, Mwazi, Barqawi, Inaqi, Swadi, Kharobi, Hmadibiadi, Sfari, Khdari, Biadi, Qrawi, and Slati, may be considered as distinct landraces. The remaining genotypes may be considered as synonymous (4) (Hmadi and Hmari, and Ajloni and Adloni), or closely related (6) landraces (Zraqi and Ghzali, Blati and Neami, and Qraee and Khurtmani). The wild fig forms clustered together and may be considered as distinct genotypes. Clustering patterns obtained from the combined (pomological and RAPD) markers had higher discriminatory power to discriminate fig landraces than using either pomological or RAPD markers alone. These results proved the importance of both pomological and RAPD markers to elucidate in part denomination problems and relationships among cultivars. Wide phenotypic and molecular diversity found in fig germplasm indicates a considerable potential for improving this crop.

Air Quality Impacts of Smallholder Oil Palm Processing in Nigeria

Air emissions during palm oil processing by smallholders are issues of public health concern demanding urgent intervention by environmentalist. In this study, six smallholder oil palm processing mills were studied inElele,Nigeria. Air emission parameters (NO2, NH3, CO, H2S, SO2, VOC), noise and meteorology (wind speed, temperature, relative humidity and pressure) were determined at three distances (10 ft,25 ftand50 ft) in both wind ward and lee ward directions from the mills covering boiling and digestion activities. The emissions from biomass were found to be significantly higher than that from fossil diesel, while noise was higher during digestion. The health implications of air emissions were discussed. The study concluded by directing attentions of regulatory agencies to monitor the activities of smallholder oil palm processing to ensure the environmental sustainability of their operations. In summary, evidence during boiling activity revealed that: · H2S ranged from - 2.400 ppm at10 ft, - 2.067 ppm at25 ftand - 0.833 ppm at50 ftfrom the mills in the wind ward direction, and - 1.167 ppm at10 ft, - 0.567 ppm at25 ftand - 0.367 ppm at50ftdistance from the mills in lee ward direction and was significantly lower during digestion. · SPM ranged from 1634 - 7853 μg/m3 at10 ft, 657 - 1110 μg/m3 at25 ftand 81 - 854 μg/m3 at50 ftfrom the mills in the wind ward direction, and 46 - 236 μg/m3 at10 ft, 44 - 120 μg/m3 at25 ftand 30 - 58 μg/m3 at50 ftfrom the mills in lee ward direction. SPM was significantly lower during digestion. · VOC ranged from 67 - 13.933 ppm at10 ft, 1.033 - 13.133 ppm at25ftand 0.500 -

Genetic Diversity of Mycosphaerella graminicola in Morocco Using Amplified Fragment Length Polymorphism

The structure of genetic diversity of Septoria tritici blotch within and among five major wheat growing regions in Morocco were assessed by AFLP （Amplified Fragment Length Polymorphism technique）. A total of 596 bands were obtained from four primers. The mean percentage of polymorphic loci over all populations was 46.56%. Nord Tangerois region had the highest loci （80.03%）, followed by Gharb region （73.66%）. The mean population diversity using Shannon information index was （I = 0.293, SE = 0.0112） and the mean gene flow was 9.12. Genetic diversity value ranged from 0.66 to 0.93 with an average of 0.78. All five populations had high levels of gene diversity. High levels of gene flow and low genetic differentiation was observed among regions （PhiPT = 0.0.057, P = 0.017）. AMOVA （Analysis of Molecular Variance） showed that there was a small but statistically significant level of genetic differentiation among populations from the five bread wheat regions. However, most of the total genetic variation （94%） occurred within wheat regions while 6% was due to genetic differentiation between these regions. Results provide evidence that sexual recombination occurs frequently in the Mycosphaerella graminicola populations sampled and that most populations are genetically differentiated over the major bread wheat growing areas in Morocco.

Wheat Genetic Transformation as Efficient Tools to Fight against Fungal Diseases

Wheat ranks first among cereal crops cultivated in the world. In its production, diseases like powdery mildew, fusarium head blight and rusts caused by fungal pathogens represent a major problem. They produce different symptoms that cause severe crop damage by infecting the spikes, leaves, roots, stems and grains. They are causing losses both by reducing the quantity of the harvested crop and the quality of the product. Quality problems of the harvested product can be due to shrivelled seed, which are frequently found as a consequence of the infection by leaf pathogens, such as mildews, rusts and Septoria. Fusarium head blight is the major culprit for mycotoxin contamination from the harvested grain, causing economic losses and in the worst casing human and animal health problems. In severe epidemics, all these fungal diseases can significantly reduce yield. Resistance to fungi is beneficial not only from a commercial point of view （yield）, but also because of the reduced levels of mycotoxins. The integration of transgenic approaches offers a potential chemical-free and environment-friendly solution for controlling fungal pathogens. This is an essential asset for wheat world food security.

Surveillance of Vibrio spp in Penaeus monodon Collected from Shrimp Pond of Satkhira, Bangladesh

Vibrio is the most common genera associated with crustaceans and often causing significant economic losses.Many Vibrio species are pathogenic to human and have been implicated in food borne diseases.The present study was conducted to identify Vibrio spp.from the tiger shrimp(Penaeus monodon)of shrimp pond at Satkhira,Bangladesh.A total number of 33 Vibrio species isolates were identified from 20 shrimp samples through a series of morphological,physiological and biochemical tests.The work reports the prevalence of Vibrio spp.in the pond environments and the existence of three Vibrio species such as V.alginolyticus,V.parahaemolyticus and V.harveyi were identified.In the study of antibiogram,all isolates were shown 100%sensitive to streptomycin,ciprofloxacin and chloramphenicol.Maximum 41%isolates were shown resistant to co-trimethaxozole whereas 30%and 24%resistant to azithromycin and novobiocin respectively.

Characterization of New Allelic Variation for Glutenin in EMS-Mutant Durum Wheat Population （Triticum turgidum L. subsp, durum （Desf.））

The High Molecular Weight HMW-GS and Low-Molecular-Weight LMW-GS Glutenin Subunits are major determinants of wheat dough processing qualities. Tilling populations was generated by EMS mutagenesis from Chaml durum variety. Protein quality was investigated by SDS sedimentation, protein content, gluten content and thousand kernel weights. 21 mutants were selected from 1,500 lines of tilling population depending on the variations of their electrophoresis profiles. The analysis of Glu-B 1 HMW-GS has showed two types of profiles： lines deficient on Bx7 and lines with expression of new protein between （Bx7-ByS） allelic pair combination. The majority of these mutant lines have showed quality compounds associated with bad technological characteristics like the parent Cham l with the exception of two mutant lines expressing new protein that have significantly stronger gluten properties an one mutant deficient on Bx7 HMW-GS that developed high value of SDS. For Glu-B3 LMW-GS coding for LMW glutenin type 1 and 2, new mutant line showing expression of new protein pattern. The mutant showing over-expression of bands on gel SDS-PAGE for LMW typel like Chaml, have produced the highest protein and gluten content, while the new mutant showing new profile have showed high value of Gluten and SDS.

Influence of conformational change of chain unit on the intrinsic negative thermal expansion of polymers

Negative thermal expansion(NTE) behavior has roused wide interest for the control of thermomechanical properties of functional materials.Although NTE behaviors have been found in kinds of compounds,it remains challenging for polymers to achieve intrinsic NTE property.In this work,we systematically studied the conformational change of dibenzocyclooctadiene(DBCOD) derivatives between chair(C) and twist-boat(TB) forms based on density-functional theo ry(DFT) calculations,and found clear evidence of the relationship between the structure of DBCOD units and the thermal contraction behavior of the related polymers.In order to obtain the polymer with NTE property,two conditions should be met for the thermal contracting DBCOD related units as follows:(i) the TB conformation can turn into C conformation as the temperature increases,and(ii) the volume of C conformation is smaller than that of TB conformation.This rule should offer a guidance to exploration of the new intrinsic NTE polymers in the future.

Cassava Genetic Transformation and its Application in Breeding

As a major source of food, cassava （Manihot esculenta Crantz） is an important root crop in the tropics and subtropics of Africa and Latin America, and serves as raw material for the production of starches and bioethanol in tropical Asia. Cassava improvement through genetic engineering not only overcomes the high heterozygosity and serious trait separation that occurs in its traditional breeding, but also quickly achieves improved target traits. Since the first report on genetic transfor- mation in cassava in 1996, the technology has gradually matured over almost 15 years of development and has overcome cassava genotype constraints, changing from mode cultivars to farmer-preferred ones. Significant progress has been made in terms of an increased resistance to pests and diseases, biofortification, and improved starch quality, building on the fundamental knowledge and technologies related to planting, nutrition, and the processing of this important food crop that has often been neglected. Therefore.cassava has great potential-in food security and bioenergy development worldwide.

N501Y mutation imparts cross-species transmission of SARS-CoV-2 to mice by enhancing receptor binding

Dear Editor,According to the World Health Organization(WHO),as of March 8,2021,the pandemic caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)had infected more than 116 million patients with coronavirus disease 2019(COVID-19)(https://covid19.who.int).The high infectivity of SARS-CoV-2 is largely attributable to the unique sequence composition of its spike(S)glycoprotein.

Heterogeneous photocatalytic degradation of diuron on zinc oxide: Influence of surface-dependent adsorption on kinetics,degradation pathway,and toxicity of intermediates

Heterogeneous photocatalytic reaction has been generally applied for degradation of toxic contaminants.Degradations of a compound using the same kind of catalyst that was synthesized differently are commonly found in literature.However,the reported degradation intermediates are normally inconsistent.This issue is especially important for the degradation of toxic compounds because intermediates may be more toxic than their parent compounds and understanding the reason is necessary if appropriate catalysts are to be designed.This work systematically compares the photocatalytic degradation of diuron,a toxic recalcitrant herbicide,on two forms of zinc oxide(ZnO),i.e.,conventional particles with zinc-and oxygen-terminated polar surfaces as the dominating planes,and nanorods with mixed-terminated nonpolar surfaces.Experimental and theoretical results indicate that both the rate of reaction and the degradation pathway depend on the adsorption configuration of diuron onto the surface.Diuron molecules adsorb in different alignments on the two surfaces,contributing to the formation of different degradation intermediates.Both the aliphatic and aromatic sides of diuron adsorb on the polar surfaces simultaneously,leading to an attack by hydroxyl radicals from both ends.On the other hand,on the mixed-terminated surface,only the aliphatic part adsorbs and is degraded.The exposed surface is therefore the key factor controlling the degradation pathway.For diuron degradation on ZnO,a catalyst confined tomixed-terminated surfaces,i.e.,ZnO nanorods,is more desirable,as it avoids the formation of intermediates with potent phytotoxicity and cytogenotoxicity.

The virological impacts of SARS-CoV-2 D614G mutation

The coronavirus diseases 2019(COVID-19)caused by the infection of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)emerged in December 2019 has caused more than 140 million infections worldwide by the end of April 2021.As an enveloped single-stranded positive-sense RNA virus,SARS-CoV-2 underwent constant evolution that produced novel variants carrying mutation conferring fitness advantages.The current prevalent D614G variant,with glycine substituted for aspartic acid at position 614 in the spike glycoprotein,is one of such variants that became the main circulating strain worldwide in a short period of time.Over the past year,intensive studies from all over the world had defined the epidemiological characteristics of this highly contagious variant and revealed the underlying mechanisms.This review aims at presenting an overall picture of the impacts of D614G mutation on virus transmission,elucidating the underlying mechanisms of D614G in virus pathogenicity,and providing insights into the development of effective therapeutics.

Phylogenetic analysis of avian infectious bronchitis virus isolates from Morocco:a retrospective study(1983 to 2014)

Dear Editor,Infectious bronchitis(IB),one of the most common and difficult poultry diseases,is caused by a gammacoronavirus named infectious bronchitis virus(IBV).IBV frequently causes respiratory and/or renal diseases in chickens and egg production losses in hens.IB has

AIM-CICs: an automatic identification method for cell-in-cell structures based on convolutional neural network

Whereas biochemical markers are available for most types of cell death, current studies on non-autonomous cell death by entosis rely strictly on the identification of cell-in-cell structures (CICs), a unique morphological readout that can only be quantified manually at present. Moreover, the manual CIC quantification is generally over-simplified as CIC counts, which represents a major hurdle against profound mechanistic investigations. In this study, we take advantage of artificial intelligence technology to develop an automatic identification method for CICs (AIM-CICs), which performs comprehensive CIC analysis in an automated and efficient way. The AIM-CICs, developed on the algorithm of convolutional neural network, can not only differentiate between CICs and non-CICs (the area under the receiver operating characteristic curve (AUC) > 0.99), but also accurately categorize CICs into five subclasses based on CIC stages and cell number involved (AUC > 0.97 for all subclasses). The application of AIM-CICs would systemically fuel research on CIC-mediated cell death, such as high-throughput screening.