Characterization of the long-term immune response to vaccination against Mycobacterium avium subsp. paratuberculosis in Danish dairy cows     

Thomsen VT  Nielsen SS  Thakur A  Jungersen G 《Veterinary immunology and immunopathology》2012,145(1-2):316-322

Vaccination of cattle against Mycobacterium avium subsp. paratuberculosis (MAP) provides partial protection by delayed shedding of MAP and reduced numbers of clinically affected animals. The duration of vaccine induced immune response is not known. The primary objective of this study was therefore to characterize the long-term effect of whole-cell based vaccination against MAP on the immune response. A secondary objective was to evaluate whether immunodiagnosis of MAP and Mycobacterium bovis infections is affected by MAP vaccination. Two studies were performed: (1) A retrospective longitudinal study including 895 vaccinated and 2526 non-vaccinated dairy cows in 9 Danish dairy herds aiming at characterizing the long-term antibody-response to vaccination; and (2) a cross-sectional study of responses in the IFN-γ assay carried out in 140 vaccinated animals in two herds to evaluate the effect of vaccination on the cell-mediated immune response and to evaluate a possible interference with the diagnosis of M. bovis infections. The results showed that 37% of samples from vaccinated animals and 5% of samples from non-vaccinated animals, respectively, were test positive in the milk antibody ELISA. The prevalence of antibody responses of the vaccinated animals was relatively constant from 2 to 6 years of age, but decreased in older animals. Among the 140 vaccinated animals 88% tested positive with the IFN-γ test to johnin PPD and 50% responded to PPDb with IFN-γ production above a similar cut-off. Although Denmark is free of M. bovis, two of the vaccinated animals responded with higher IFN-γ levels when cultured with PPDb compared to PPDa. In conclusion, immunization with whole-cell MAP vaccines elicits both humoral and cell-mediated immune reactions, which may interfere with surveillance and diagnosis of both MAP and M. bovis infections using currently available tests.  相似文献   

Longitudinal study comparing the dynamics of Clostridium difficile in conventional and antimicrobial free pigs at farm and slaughter     

Susick EK  Putnam M  Bermudez DM  Thakur S 《Veterinary microbiology》2012,157(1-2):172-178

Clostridium difficile is the leading cause of nosocomial diarrhea in humans and a major cause of enteritis in neonatal piglets, foals and calves. The aim of this longitudinal study was to determine and compare the prevalence, antimicrobial susceptibility, and toxinotype profiles of C. difficile isolated from pigs and their environment in the indoor conventional and outdoor antimicrobial free (ABF) production systems. Ten conventional and eight ABF cohorts of 35 pigs each and their environment were sampled at different stages of production at farm and slaughter. C. difficile prevalence in pigs was highest at the farrowing stage in both conventional (34%, 120/350) and ABF (23%, 56/244) systems, and decreased with age. This reduction in C. difficile prevalence in pigs at later stages of production mirrored the decreased prevalence in the farm environment. At slaughter, C. difficile was isolated at a low frequency from the carcasses and processing environment in both production systems. All but three isolates were resistant to ciprofloxacin (99%, 505/508), while 1.0% (5/508) and 6.0% (23/508) of isolates exhibited resistance to tetracycline and erythromycin, respectively. Toxinotype V (tcdA(+)tcdB(+)) was the predominant strain identified in both systems (conventional: 94%, 376/401; ABF: 82%, 88/107), while the rest were toxinotype XIII (tcdA(+)tcdB(+)). To conclude, we isolated antimicrobial resistant C. difficile regardless of antimicrobial use on the farm. Based on the phenotypic and genotypic similarity of C. difficile isolated in this study, we conclude that the unique production practices employed in conventional and ABF production systems have no impact on the pathogen population.  相似文献   

Expression of drought responsive genes in pigeonpea and in silico comparison with soybean cDNA library     

Nagaraja Deeplanaik  Ramesh Chapeyil Kumaran  Krishna Venkatarangaiah  Santosh Kumar Hulikal Shivashankar  Dadakhalandar Doddamani  Sandeep Telkar 《Journal of Crop Science and Biotechnology》2013,16(4):243-251

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Increasing the ex vivo antigen-specific IFN-γ production in subpopulations of T cells and NKp46+ cells by anti-CD28, anti-CD49d and recombinant IL-12 costimulation in cattle vaccinated with recombinant proteins from Mycobacterium avium subspecies paratuberculosis     

Aneesh Thakur  Ulla Riber  William C. Davis  Gregers Jungersen 《Veterinary immunology and immunopathology》2013

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Assessment of biomass and net primary productivity of a dry tropical forest using geospatial technology     

Tarun Kumar Thakur  S.L.Swamy  Arvind Bijalwan  Mammohan J.R.Dobriyal 《林业研究》2019,(1):157-170

This study quantifies biomass, aboveground and belowground net productivity, along with additional environmental factors over a 2-3 year period in Barnawapara Sanctuary of Chhattisgarh, India through satellite remotesensing and GIS techniques. Ten sampling quadrates20×20, 5×5 and 1×1 m were randomly laid for overstorey (OS), understorey (US) and ground vegetation(GS), respectively. Girth of trees was measured at breast height and collar diameters of shrubs and herbs at 0.1 m height. Biomass was estimated using allometric regression equations and herb biomass by harvesting. Net primary productivity (NPP) was determined by Ssumming biomass increment and litter crop values. Aspect and slope influenced the vegetation types, biomass and NPP in different forests. Standing biomass and NPP varied from 18.6 to101.5 Mg ha^-1 and 5.3 to 12.7 Mg ha^-1 a^-1, respectively,in different forest types. The highest biomass was found in dense mixed forest, while net production recoded in Teak forests. Both were lowest in degraded mixed forests of different forest types. OS, US and GS contributed 90.4, 8.7and 0.7%, respectively, for the total mean standing biomass in different forests. This study developed spectral models for the estimation of biomass and NPP using Normalized Difference Vegetation Index and other vegetation indices.The study demonstrated the potential of geospatial tools for estimation of biomass and net productivity of dry tropical forest ecosystem.  相似文献   

Nitrogen metabolism and seed composition as influenced by glyphosate application in glyphosate-resistant soybean     

Bellaloui N  Zablotowicz RM  Reddy KN  Abel CA 《Journal of agricultural and food chemistry》2008,56(8):2765-2772

Previous research has demonstrated that glyphosate can affect nitrogen fixation or nitrogen assimilation in soybean. This 2-year field study investigated the effects of glyphosate application of 1.12 and 3.36 kg of ae ha(-1) on nitrogen metabolism and seed composition in glyphosate-resistant (GR) soybean. There was no effect of glyphosate application on nitrogen fixation as measured by acetylene reduction assay, soybean yield, or seed nitrogen content. However, there were significant effects of glyphosate application on nitrogen assimilation, as measured by in vivo nitrate reductase activity (NRA) in leaves, roots, and nodules, especially at high rate. Transiently lower leaf nitrogen or (15)N natural abundance in high glyphosate application soybean supports the inhibition of NRA. With the higher glyphosate application level protein was significantly higher (10.3%) in treated soybean compared to untreated soybean. Inversely, total oil and linolenic acid were lowest at the high glyphosate application rate, but oleic acid was greatest (22%) in treated soybean. These results suggest that nitrate assimilation in GR soybean was more affected than nitrogen fixation by glyphosate application and that glyphosate application may alter nitrogen and carbon metabolism.  相似文献   

Design of Optimum Response Surface Experiments for Electro-Coagulation of Distillery Spent Wash     

R. Krishna Prasad  R. Ram Kumar  S. N. Srivastava 《Water, air, and soil pollution》2008,191(1-4):5-13

Electro-coagulation (EC) of a distillery spent wash has been optimized by Box–Behnken design of surface response analysis in terms of color removal. The design was employed to derive a statistical model for the effect of parameters studied on removal of color using iron anodes. The current density (31 mA/cm²), dilution (17.5%) and time of electrolysis (4 hours) had been found to be the optimum conditions for maximum 95% color removal. The actual color removal at optimized conditions was found to be 93.5% which confirms close to the predicted response using response surface methodology.  相似文献   

Biocontrol potential of Pseudomonas azotoformans,Serratia marcescens and Trichoderma virens against Fusarium wilt of Dalbergia sissoo     

Sabyasachi Banerjee  Seema Singh  Shailesh Pandey  Maneesh S. Bhandari  Amit Pandey  Krishna Giri 《Forest Pathology》2020,50(2)

Wilt disease caused by Fusarium solani is a serious constraint to Dalbergia sissoo (shisham) plantations in northern India. In this study, the antagonistic potential of 40 bacterial isolates recovered from rhizophere soil of healthy shisham trees, and a well‐characterized Trichoderma species (Trichoderma virens) were tested for their possibility as biocontrol agents for F. solani. Two promising isolates (S1 and S15) were identified which inhibited pathogen growth, caused chitin degradation, produced siderophores and solubilized phosphate in vitro. Isolate S15 scored highest for hydrogen cyanide (HCN) production while isolate S1 was a non‐HCN producer. These two isolates were identified as Serratia marcescens (S1) and Pseudomonas azotoformans (S15) following sequence analysis of 16S rDNA. In dual culture assays, T. virens caused 80% inhibition of mycelial growth of the test fungus. The three selected antagonists when tested in planta in the glasshouse completely suppressed production of wilt symptoms on 12‐month‐old shisham plants. Further work is needed to ascertain the potential of these isolates to be used as biocontrol agents to manage shisham wilt under field conditions.  相似文献   

Effects of salinity on growth characteristics and osmoregulation of juvenile cobia,Rachycentron canadum (Linnaeus 1766), reared in potassium‐amended inland saline groundwater     

Jose Antony  Appidi Krishna Reddy  Arun Sudhagar  Hari Krishna Vungurala  Luke A Roy 《Journal of the World Aquaculture Society》2021,52(1):155-170

The suitability of inland saline groundwater as a medium to culture juvenile cobia, Rachycentron canadum, was assessed. In the first experiment, juvenile cobia stocked in raw (unamended) saline groundwater at salinities of 5, 10, and 15 g/L exhibited complete mortality after 108, 176, and 195 hr, respectively. The second experiment evaluated the rearing of juvenile cobia (mean weight ~9.23 ± 0.12 g) in potassium (K⁺)‐amended saline groundwater (100% K⁺ fortified) and reconstituted seawater at salinities of 5, 10, and 15 g/L to assess growth and osmoregulation in distinct culture media. Following 60 days of culture, all fish survived the experimental period. Final mean bodyweight of cobia reared in K⁺‐amended saline groundwater (103.2–115.8 g) and seawater (111.2–113.8 g) of different salinities did not vary significantly (p > .05). No differences (p > .05) were observed in specific growth rate, weight gain (%), and feed conversion ratio between treatment groups. Serum osmolality increased with salinity and was significantly higher (p < .05) for fish in K⁺‐amended saline groundwater (353–361 mOsmol/Kg) than in reconstituted seawater (319–332 mOsmol/Kg), although differences were not observed between salinities by water type. Cobia stocked in saline groundwater of different salinities were osmoregulating normally, and the higher values observed may be because of variations in ionic composition and other interfering ions in saline groundwater. Trial results suggest that juvenile cobia can achieve optimal growth in K⁺‐amended saline groundwater of low and intermediate salinities.  相似文献   

Adoption and Impact of Modern Rice Varieties on Poverty in Eastern India     

Kwasi Bannor Richard  Amarnath Krishna Kumar Gupta  Oppong-Kyeremeh Helena  Abawiera Wongnaa Camillus 《水稻科学》2020,27(1):56-66

The factors affecting the adoption of modern varieties(MVs) of rice and impact on poverty in Odisha, India were discussed. A total of 363 households from Cuttack and Sambalpur districts of Odisha via multistage sampling technique participated in the survey. The Cragg's Double hurdle model was used to model the determinants of adoption and intensity of adoption of MVs of rice, and the propensity score matching was used to analyze the impact of adoption on poverty. The results showed that age, education, risk aversion, land size, yield, perception of MVs as high yielding, resistant to diseases and availability of MVs positively influenced the decision to adopt. However, variables such as household size, experience of a farmer, off-farm job participation, amount of credit received, cost of seeds, insecticides and fertilizers negatively influenced the adoption of MVs. Intensity of adoption of MVs was negatively influenced by experience of a farmer, cost of fertilizer and marketability of MVs, and positively affected by household size, risk aversion, land size, cost of insecticides, perception of MVs as high yielding and availability of MV seeds. Poverty incidence, gap and severity were high among non-adopters to adopters of MVs. After matching adopters and non-adopters of MV groups using four different algorithms of nearest neighbour matching, stratification matching, radius matching and kernel matching, the impact of MV adoption resulted in higher per capita monthly household expenditure by about US$ 52.82 to US$ 63.17.  相似文献