Biologic and genetic comparison of Toxoplasma gondii isolates in free-range chickens from the northern Pará state and the southern state Rio Grande do Sul, Brazil revealed highly diverse and distinct parasite populations     

Dubey JP  Sundar N  Gennari SM  Minervino AH  Farias NA  Ruas JL  dos Santos TR  Cavalcante GT  Kwok OC  Su C 《Veterinary parasitology》2007,143(2):182-188

The prevalence of Toxoplasma gondii in 84 free-range chickens (34 from the northern Pará state, and 50 from Rio Grande do Sul, the southern state) from Brazil, South America was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 39 (46.4%) of 84 chickens with titers of 1:10 in one, 1:20 in two, 1:40 in four, 1:80 in seven, 1:160 in five, 1:320 in six, 1:640 in eight and > or =1:1280 in six. Hearts and brains of 45 chickens with titers of 1:20 or less were pooled and fed to two T. gondii-free cats. Hearts and brains of 39 chickens with titers of 1:10 or higher were bioassayed in mice. Feces of cats were examined for oocysts. One cat fed tissues from 31 chickens with titers of less than 1:10 from Rio Grande do Sul shed T. gondii oocysts. T. gondii was isolated by bioassay in mice from 33 chickens with MAT titers of 1:20 or higher. All infected mice from 10 isolates died of toxoplasmosis. All 34 isolates (15 from Pará, 19 from Rio Grande do Sul) were genotyped using 11 genetic markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, a new SAG2 and Apico. Eleven genotypes were revealed for Pará isolates and seven genotypes for Rio Grande do Sul. No genotype was shared between the two geographical locations. These data suggest that T. gondii isolates are highly diverse and genetically distinct between the two different regions in Brazil that are 3500 km apart.  相似文献   

Sarcocystosis in a Stillborn Lamb     

JS Agerholm  JP Dubey 《Reproduction in domestic animals》2014,49(6):e60-e63

Confirmed congenital sarcocystosis has been reported extremely rarely in domestic ruminants. Sarcocystosis was diagnosed in a stillborn lamb with microscopic lesions predominantly in the central nervous system and placenta. Encephalitis was characterized by multiple foci of glial nodules some with central necrosis, perivascular cuffing and vascular occlusion, while placental lesions consisted of multifocal necroses, inflammation and mild calcification. Immature and mature schizonts were found in vascular endothelium of several organs. It is suggested that the protozoa were Sarcocystis tenella based on their morphology, location and as this is the most pathogenic Sarcocystis sp. parasitizing sheep.  相似文献   

Microprojectile mediated plant transformation: A bibliographic search   总被引：2，自引：0，他引：2  

Rajesh Luthra  Varsha  Rajesh K. Dubey  Ashok K. Srivastava  Sushil Kumar 《Euphytica》1997,95(3):269-295

This bibliographic search covers the literature till December, 1995 on microprojectile mediated plant transformation, plasmid construct used, and the type of expression obtained, since the inception of the concept by Sanford et al., in 1987. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Influence of NaCl Salinity on Growth and Metabolic Status of Protein and Amino Acids in Rice Seedlings     

R. S. Dubey  Manju  Rani 《Journal of Agronomy and Crop Science》1989,162(2):97-106

Seeds of four rice cultivars differing in salt tolerance when grown under increasing level of NaCl salinity and seedling vigour as well as metabolic status of total and soluble proteins, amino acids were evaluated in seedlings at increasing days of growth it was observed that increasing level of salinity caused loss in dry wt. of seedlings as well as reduction in lengths of root and shoot. In both sets of cultivars salt stressed seedlings showed higher levels of total as well as soluble proteins, total amino acids compared to non salinized seedlings. In roots of salt susceptible cvs. Ratna and Jaya increased salinity up to 14 mmhos/cm remarkably increased total as well as soluble protein level whereas in shoots moderate level of salinity increased protein level compared to controls and higher salinity level caused suppression in such increase. Tolerant cultivars always maintained higher levels of total as well as soluble proteins and total amino acids in salt stressed seedlings compared to susceptibles. Amino acids which accumulated greatly in salinized seedlings were arginine, phenylalanine, alanine, leucine, proline, valine and glutamine. Results suggest possible role of proteins and amino acids in confering salt tolerance in rice.  相似文献   

Genetic diversity of the pea root pathogen Aphanomyces euteiches in Europe     

Carol Kälin  Anna Berlin  Agnese Kolodinska Brantestam  Mukesh Dubey  Anna-Kerstin Arvidsson  Paul Riesinger  Malin Elfstrand  Magnus Karlsson 《Plant pathology》2022,71(7):1570-1578

The oomycete pathogen Aphanomyces euteiches causes root rot in various legume species. In this study we focused on A. euteiches causing root rot in pea (Pisum sativum), thereby being responsible for severe yield losses in pea production. We aimed to understand the genetic diversity of A. euteiches in Europe, covering a north-to-south gradient spanning from Sweden, Norway and Finland to the UK, France and Italy. A collection of 85 European A. euteiches strains was obtained, all isolated from infected pea roots from commercial vining pea cultivation fields. The strains were genotyped using 22 simple-sequence repeat markers. Multilocus genotypes were compiled and the genetic diversity between individual strains and population structure between countries was analysed. The population comprising strains from Italy was genetically different and did not share ancestry with any other population. Also, strains originating from Finland and the eastern parts of Sweden were found to be significantly different from the other populations, while strains from the rest of Europe were more closely related. A subset of 10 A. euteiches strains from four countries was further phenotyped on two susceptible pea genotypes, as well as on one genotype with partial resistance towards A. euteiches. All strains were pathogenic on all pea genotypes, but with varying levels of disease severity. No correlation between the genetic relatedness of strains and virulence levels was found. In summary, our study identified three genetically distinct groups of A. euteiches in Europe along a north-to-south gradient, indicating local pathogen differentiation.  相似文献   

Isolation and pathotyping of H9N2 avian influenza viruses in Indian poultry     

Nagarajan S  Rajukumar K  Tosh C  Ramaswamy V  Purohit K  Saxena G  Behera P  Pattnaik B  Pradhan HK  Dubey SC 《Veterinary microbiology》2009,133(1-2):154-163

A total of 1246 faecal and tissue samples collected/received from 119 farms located in various states of India were processed for isolation of avian influenza viruses (AIV) during 2003-2004 as part of a program to monitor AIV infection in Indian poultry population. Avian influenza virus was isolated for the first time in India from poultry farms with history of drop in egg production, respiratory illness and increased mortality in Haryana state. A total of 29 H9N2 AIV isolates were obtained from the states of Punjab, Haryana, Uttar Pradesh, Gujarat, and Orissa and Union Territory Delhi. Subtyping was done by HI, RT-PCR and neuraminidase inhibition assay. Pathotyping of six representative isolates by intravenous pathogenicity index (0.0/3.0) in 6-8 weeks old chicken, trypsin dependency in cell culture and HA cleavage site analysis (335RSSR*GLF341) confirmed that these isolates are low pathogenic. Nucleotide sequence analysis of the HA gene showed that the Indian isolates are very closely related (95.0-99.6%) and shared a homology of 92-96% with H9N2 isolates from Germany and Asian regions other than that of mainland China. Deduced amino acid sequences showed the presence of L226 (234 in H9 numbering) which indicates a preference to binding of alpha (2-6) sialic acid receptors. Two of the six isolates had 7 glycosylation sites in the HA1 cleaved protein and the remaining four had 5 sites. Phylogenetic analysis showed that they share a common ancestor Qa/HK/G1/97 isolate which had contributed internal genes of H5N1 virus circulating in Vietnam. Further characterization of Indian H9N2 isolates is required to understand their nature and evolution.  相似文献