Antibacterial Effects of Chinese Herbal Medicines against Streptococcus iniae in Oreochromis niloticus

In this study, the antibacterial effects of Chinese herbal medicines against Streptococcus iniae in Oreochromis niloticus were investigated by drug sensitiv- ity test. The results indicated that Streptococcus in/ae was extremely sensitive to Calla Chinensis, Fructus Hippophae and Fructus Murne, highly sensitive to Sappan Lignum, Pericarpium Granati, Folium Eucalypti and Radix Scutellariae, moderately sensitive to Rh/zoma Coptidis, Radix et Rhizoma Rhei, Flos Caryophyllata, Cortex phellodendri and Rabdosia serra （ Maxim. ） Hara, and insensitive to Herba Portulacae , Herba Houttuyniae , Polygonum hydropiper L. , Herba Menthae , Radix Glycyrrhizae , Pericarpium Citri Reticulatae , Herba Andrographitis and Rhizoma Acori Tatarinowii. Chinese medicinal herbs which Streptococcus iniae was extremely sensitive or moderately sensitive to were selected and prepared into three Chinese herbal medicine formulae for medicated bath of Oreochromis niloticus infected arti- ficially with Streptococcus iniae. The results showed that medicated bath elicited therapeutic effects on infected Oreochromis niloticus. Formula II exhibited the best therapeutic effect with an effective percentage of 90%.

Cloning of catalase gene and antioxidant genes in Scophthalmus maximus response to metalloprotease of Vibrio anguillarum stress

Metalloproteases represent a class of extracellular proteases found in Vibrio anguillarum that can generate toxic and pathogenic eff ects in turbot(Scophthalmus maximus).The toxicological eff ect partly results from oxidative damage due to the production of excessive reactive oxygen species(ROS).Catalase(CAT),superoxide dismutase(SOD),and glutathione peroxidase(GPx)are major antioxidant enzymes induced by various oxidative stresses and can scavenge peroxides generated in cells.To evaluate the eff ects of metalloprotease-induced ROS on the antioxidation defense mechanism of S.maximus head kidney cells,the cDNA of CAT gene(designated as SmCAT)was cloned and characterized.SmCAT comprises a 1584-bp coding sequence that encodes a protein containing 527 amino acids with a poly(A)tail.Bioinformatics analysis revealed an active site signature sequence,a heme-ligand signature sequence,and three catalytic amino acid residues.The deduced SmCAT amino acid sequence shares a sequence similarity of 66.1%-92.4%with those of other species.Phylogenetic analysis revealed that SmCAT is classifi ed with CAT of other fi shes.Quantitative real-time PCR analysis showed that SmCAT was extensively expressed in all tested tissues,especially in blood.The expression of SmCAT,SmMnSOD,and SmGPx were inhibited signifi cantly in head kidney cells treated with metalloprotease from 12 to 24 h.In 6 to 24 h metalloprotease-treated groups compared to that of the untreated group,it was found that the production of ROS was markedly increased,and the mitochondrial membrane potential was decreased considerably.Hoechst 33342 staining revealed the presence of apoptotic bodies when the cells were incubated with 8.0 or 40.0μg/mL metalloprotease for 12 and 24 h.Hence,the toxic eff ects of metalloprotease are associated with the down-regulation of antioxidant enzyme expression and increased ROS levels,which trigger the activation of apoptosis in the head kidney cells of turbot.Our fi ndings provide a better understanding on the mechanism of metalloprotease-induced apoptosis in fi sh.

Effect of Echinacea Polysaccharide on Secretion of IL-1αmRNA by IEC-6 Injured by LPS

[ Objective ] This study was conducted to investigate Echinacea polysaccharide （EPS） on expression of tumor necrosis factor （TNF） under injury of intestinal epithelial cells （IEC-6） by lipopolysaccharide （LPS）, so as to discuss the action mechanism of EPS to injured cells. [Method] Total DNA was extracted with TRIzon reagent, TNF-α mRNA was amplified, and the amplification products were subjected to agarose gel electrophoresis and imaging. [Result] 50 μg/ml EPS could partially inhibited the production of IL-α mRNA by IEC-6 under the stimulation of LPS, while the inhibition of 2（10 and 500 μg/ml EPS on the level of IL-1α mRNA gradually increased with the concentration increasing; and IEC-6 cells pretreated with 50,100,200 and 500 μg/ml EPS for 24 h and then stimulated by 10 μml IPS for 1 and 4 h were analyzed by RT-PCR method, and it was found that the expression of IL-α mRNA induced by LPS could be effectively inhibited by EPS, and the inhibition rate at 4 h was higher than that at 1 h. [ Conclusion] EPS could play its role of protecting intestinal mucosa by inhibiting the secretion of IL-1α mRNA by cells under the stimulation of LPS, and such inhibition effects of EPS had concentration dependency and time dependency.

Effects of Two Drugs on Small Intestinal Epithelial Lymphocytes of Experimental Piglets with Spleen Deficiency

[ Objective] This study aimed to investigate the effects of Guchang Cuzhang powder and Smecta on small intestinal epithelial lymphocytes of piglets with spleen deficiency and diarrhea induced by Reserpine. [ Method] Eighteen piglets with reserpine-induced spleen deficiency and diarrhea were selected and randomly divided into three groups, six per group, including Guchang Cuzhang powder group, Smeeta group and spleen deficiency control group. Piglets in two drug adnfinistration groups were treated for 7 d using Guchang Cuzhang powder and Smecta, respectively. On the 2nd d and 8th d after drug withdrawal, three piglets in each group were euthanized by jugular vein bleeding to death. Intestine segments in different groups were collected for paraffin embedding, section preparation and HE staining, to conduct histological observation and count the number of small intestinal epithelial lymphocytes. [ Result ] Compared with the spleen deficiency control group, the number of lymphocytes in small intestinal epithelium of piglets in two drug administration groups increased significantly; in addition, the number of lymphocytes in small intestinal epithelium of piglets in Guchang Cuzhang powder group was significantly higher than that in Smecta group. [ Conclusion ] This study provided theoretical basis for the clinical applieation of Guchang Cuzhang powder and Smecta.

Isolation,Identification and Drug Tolerance Analysis of Pathogenic Staphylococcus aureus from Broilers

White feather broilers in some broiler farm in Chengde area developed arthritis and died acutely. In order to identify the pathogen inducing the disease and death of the white feather broilers, samples such as livers and joint pus were collected from dead broilers under sterile condition, and one pathogenic strain was isolated. The isolate was identified to be Staphylococcus aureus through isolated culture, morphologic observation, inspection of biochemical property and animal test. The drug sensitivity test showed that the isolate was sensitive to ceftazidime, enrofloxacin, ceftriaxone, lincomycin and amikacin, but resistant to other drugs to different degrees.

PCR Detection of Streptococcus agalactiae in Dairy Cows Suffering from Mastitis

[ Objective ] This study aimed to identify Streptococcus agalactiae and lay the foundation for the prevention and control of mastiffs in dairy cows. [ Method] Ten strains were isolated from milk samples produced by diseased dairy cows suffering from mastitis for morphologic observation, culture characteristic investigation, biochemical identification and Lancefield grouping. The isolated strains were identified at the molecular level by nested-PCR. [ Result] Among the ten isolates, six strains were 13-hemolytic and Gram-positive on blood agar, belonging to Lancefield group B, which were identified as Streptococcus agalactiae by biochemical identification and nested-PCR. After overnight incubation, the coincidence rate between results of nested-PCR detection and biochemical identification reached 100%. [ Conclusion ] Bacterial incubation, rapid DNA extraction and specific PCR can provide basis for early epidemiological survey of Streptococcus agalactiae infection in cattle.

Screening of Chinese Herbal Medicines against Avian Infectious Laryngotracheitis Virus and Escherichia coli

[ Objective] This study aimed to screen Chinese herbal medicines against avian infectious laryngotracheitis virus and Escherichia coli. [ Method ] Conventional Chinese medicine plate dilution method, plate punching method and test tube method were applied to screen Chinese herbal medicines against avian infectious laryngotracheitis virus based on chicken embryo inoculation experiment. [ Result ] Forsythia suspensa, Radix lsatidis, Isatis iadigotica, Lonicera japonica, Codonopsis pilosula, Astragalus membranaceus, Rhizoma Atractylodis Macrocephalae, C, tyeyrrhiza uralensis and Pericarpium granati had relatively strong anti-ILTV effect; among the Chinese herbal medicines against avian E. coli, Sanguisorba offwinalis, Fructus Mume, Rheum palmatum, Anemarrhena asphodeloides, Radix Scutellariae and Fagopyrum cymosum had relatively strong effect against avian E. coli Os, while other Chinese herbal medicines had relatively weak or no inhibitory effect on avian E. coli 0s and 05. [ Conclusion] This study laid the foundation for further development of Chinese herbal medicine compound preparations to treat avian infectious laryngotracheitis, avian colibacillosis and other viral diseases and bacterial diseases.

Histopathological Observation of Goose Escherichia coli Disease

[ Objective] This study aimed to provide reliable basis for in-depth understanding of histopathological changes in geese suffering from Escherichia coli disease and accurate diagnosis of goose E. coli disease. [ Method] By using paraffin embedding, section slicing and HE staining, histopathological changes in the heart, liver, spleen, lung, kidney and small intestine tissues of three diseased geese were observed. [ Result] The liver generated protein fiber membranes, showing liver cell degeneration, increasing number of red blood cells in sinusoids and liver congestion; the kidney had relatively serious lesions, including renal tubular epithelial cell degeneration, necrosis and shedding from the basement membrane and hyaline degeneration of glomerulars. The lung showed epithelial cell degeneration and necrosis and was filled with a large number of red blood cells and shedded epithelial cells, showing typical red hepatization; a large number of red blood ceils were aggregated in pulmonary blood vessels, resulting in lung congestion. Epithelial ceils of various digestive tubes all showed varying degrees of minor shed- ding and local infiltration of inflammatory ceils, thereby leading to death of geese due to substance metabolism, electrolyte and acid-base balance disorders and metabolic acidosis. [ Conclusion] Based on epidemiology survey, clinical symptom observation, pathological necropsy and laboratory diagnosis, the diseased geese were confirmed to be suffering from E. coli disease.

Histopathological Observation of Classical Swine Fever in Newborn Piglets

[ Objective] This study aimed to investigate pathological changes in various organs of piglets infected with classical swine fever and provide reliable basis for accurate diagnosis of classical swine fever. [ Method] By using paraffin embedding, section slicing and HE staining, histopathological changes in the heart, liver, spleen, lung, kidney and small intestine tissues of five diseased piglets were observed. C Result] Classical swine fever virus could lead to multiple visceral and mueosal hemorrhages, inflammatory cell infiltration, necrosis and other pathological changes. [ Conclusion ] Classical swine fever virus can further cause progressive degeneration and necrosis of different cells, resulting in immune injury.

Histopathological Observation of Cynoglossus semilaevis Günther with Abdominal Dropsy in Industrial Aquaculture

[ Objective] This study aimed to investigate and analyze the histopathological changes in various tissues and organs of Cynoglossus semilaevis Gunther with abdominal dropsy. [ Method] By HE staining, pathological tissues of main organs of C. semilaevis Giinther with abdominal dropsy were observed. [ Result] According to the results of histopathological observation, C. semilaevis Gilnther with abdominal dropsy exhibited a large amount of ascites in the abdominal cavity; small intestinal mucosal epithelial cells were denatured and necrotic, and shed into the enteric cavity, with submucosal vascular congestion; the liver and pancreas tissues were denatured and necrotic, and the morphology of most liver cells disappeared. However, there was no remarkable pathological change in the heart, spleen and other organs. [ Conclusion] C. semilaevis Gtinther with abdominal dropsy exhibited serious pathological and histochemical lesions in the small intestine, liver and pancreas, causing metabolic disorders.

Antibiotic Sensitivity Test and Detection of Sulfonamide Resistance Gene Sul2 in Escherichia coli Isolates from Swine

[ Objective] This study aimed to analyze antibiotic sensitivity and detect sulfonamide resistance gene Sul2 in 17 Escherichia coli isolates from swine. [ Method] The antibiotic sensitivity of 17 E. coil isolates from swine was analyzed with Kirby-Bauer disk diffusion method. Sulfonamide resistance gene Sul2 was detected by PCR amplification with the extracted genomic DNA as a template. [ Result] The 17 swine-derived E. coli isolates from different regions were resistant to various antibiotics and exhibited different multi-antibiotic resistance phenotypes, including nine isolates resistant to sulfamethoxazole, seven isolates resistant to oxacillin, ten isolates resistant to cefazolin and eight isolates resistant to erythromycin. Sulfonamide resistance gene Sul2 was successfully amplified from genomic DNA of E. coli isolates. The PCR results were basically consistent with antibiotic resistance phenotypes of these strains. [ Conclusion] Sul2 gene was widespread in swine-derived E. coli, which was closely associated with sulfonamide resistance phenotvpes of E. coli.

Histopathological Observation of Parvovirus Infection in Foxes

In this study, histopathological changes in the heart, liver, spleen, lung, kidney, intestine, brain and other organs of foxes died of parvovims infection were observed. According to the results, multiple organs of infected foxes were congested and hemorrhaged with tissue damage, inflammatory cell infiltration and a series of pathological changes, mainly exhibiting hepatic cell cord rupture, liver cell granular degeneration and fatty degeneration, small intestinal mucous mem- brane shedding, intestinal villi necrosis and shedding, severe hemorrhage of lamina pmpria with inflammatory cell infiltration, and severe small intestinal bleeding. This study laid a solid foundation for clinical diagnosis, prevention and treatment of parvovirus infection in foxes.

Isolation and Identification of a Pathogenic E.coli Strain Causing Diarrhea in Foxes

[Objectives] The study aimed to identify the pathogenic E. coli strain that caused diarrhea in foxes and to analyze its drug sensitivity.[Methods] A pathogenic E. coli strain was isolated from dead foxes with diarrhea. By conventional bacterial isolation and culture, morphological observation, pathogenicity test and K-B disc method, the isolated strain was identified as pathogenic E. coli .[Results] The isolated pathogen was highly sensitive to ceftriaxone, cefotaxime, ciprofloxacin and lincomycin, moderately sensitive to enrofloxacin, neomycin, gentamycin, spectinomycin, florfenicol, amikacin and polymyxin, and resistant to ampicillin, amoxicillin and doxycycline.[Conclusions] This study provided reference for the prevention and control of diarrheal diseases in foxes in Qinhuangdao region.

Isolation, Identification and Drug Sensitivity Test of a Pathogenic Escherichia coli Strain from Minks with Diarrhea

[Objectives] The study aimed to identify the pathogen that causes diarrhea in minks. [Methods] Liver tissues were aseptically collected from dead minks with diarrhea. By bacterial isolation and culture,morphological observation,biochemical test and pathogenicity test,the isolated strain was identified as pathogenic E. coli. [Results]The pathogen causing diarrhea in minks was confirmed as a pathogenic E. coli strain. Drug sensitivity test indicated that the isolated pathogenic E. coli strain was highly sensitive to ceftazidime,cefotaxime,enrofloxacin,florfenicol and cephradine,moderately sensitive to ampicillin,ciprofloxacin,amikacin,doxycycline,lincomycin and gentamycin,and resistant to amoxycillin,neomycin,spectinomycin,polymyxin and penicillin. [Conclusions] This study provided reference for the prevention and control of abortion in female minks in Qinhuangdao region.