Carcinogens and human health: Part 1     

F P Perera 《Science (New York, N.Y.)》1990,250(4988):1644-1646

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Relative importance of larval and adult Mecistocirrus digitatus in inducing resistance to a reinfection in calves     

S T Fernando  V K Gunawardane  S Sivanathan  B M Perera  T A Bongso 《Veterinary parasitology》1987,23(1-2):83-93

Calves immunized with adult Mecistocirrus digitatus implanted directly into the abomasum did not develop a substantial degree of immunity to a subsequent large oral (challenge) dose of larvae, which developed to maturity. In contrast animals immunized by oral infection developed strong resistance. The calves implanted with adult worms appeared to show a greater degree of susceptibility to maturation of the challenge infection than controls which received a challenge of the same magnitude without any previous immunization. The implanted female adult worms established in the hosts and continued to produce more eggs for a longer time than those which developed to maturity from the oral immunizing infection with third-stage larvae. Passive haemagglutination studies revealed that the implanted adult worms stimulated little or no antibody response in the hosts. In the calves which did not show a response to the adult worm implant the subsequent challenge with an oral infective dose of third-stage larvae also failed to stimulate a response. Likewise the two calves from the group which showed a weak antibody response to the adult worm implant did not show an increased response when challenged. In contrast, calves immunized with an oral infection of third-stage larvae had an antibody response which showed a vigorous rise on challenge in four of the five calves. Thus a direct relationship between resistance to challenge infection and the antibody response determined by the passive haemagglutination and gel-diffusion tests was observed in the calves immunized orally.  相似文献   

Observations on the use of etorphine alone and in combination with acepromazine maleate for immobilisation of aggressive Asian elephants (Elephas maximus)     

T A Bongso  B M Perera 《The Veterinary record》1978,102(15):339-340

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Validation of a human progesterone enzyme immunoassay (EIA) kit for use on serum of cattle in Cameroon     

Bayemi PH  Nsongka VM  Perera BM  Cavestany D  Webb EC 《Tropical animal health and production》2007,39(5):335-338

A study aimed at validating a human progesterone enzyme immunoassay kit was carried out on cattle at Bambui, Cameroon. Progesterone ELISA Kits (EH-511) were obtained from Clinpro International. Forty-one cows were selected, of which 19 were pregnant and 22 within 14 days post partum. Blood samples were analysed and progesterone levels were deduced from a curve obtained from standard absorbance values (A ₄₅₀). Results show that 95.5% of postpartum cows had progesterone levels below 1 ng/ml, with the highest level being 0.75 ng/ml. The mean level was 0.5 ± 0.26 ng/ml. The cows in the ‘pregnant group’ had progesterone levels ranging from 3.5 to 17.5 ng/ml. This kit can be used for measuring progesterone levels in cattle. Levels of 1 ng/ml for two consecutive samples or one sample at or above 3 ng/ml are an indication of the presence of corpus luteum, while cows below 1 ng/ml will be in anoestrus.  相似文献   

Actin Polymerization: An Event Regulated by Tyrosine Phosphorylation During Buffalo Sperm Capacitation          下载免费PDF全文

S Naresh  SK Atreja 《Reproduction in domestic animals》2015,50(6):1047-1053

In the female reproductive tract, the spermatozoa undergo a series of physiological and biochemical changes, prior to gaining the ability to fertilize, that result to capacitation. However, the actin polymerization and protein tyrosine phosphorylation are the two necessary steps for capacitation. In this study, we have demonstrated the actin polymerization and established the correlation between protein tyrosine phosphorylation and actin reorganization during in vitro capacitation in buffalo (Bubalus bubalis) spermatozoa. Indirect immunofluorescence and Western blot techniques were used to detect actin polymerization and tyrosine phosphorylation. The time‐dependent fluorimetric studies revealed that the actin polymerization starts from the tail region and progressed towards the head region of spermatozoa during capacitation. The lysophosphatidyl choline (LPC)‐induced acrosome reaction (AR) stimulated quick actin depolymerization. The inhibitor cytochalasin D (CD) blocked the in vitro capacitation by inhibiting the actin polymerization. In addition, we also performed different inhibitor (Genistein, H‐89, PD9809 and GF‐109) and enhancer (dbcAMP, H₂O₂ and vanadate) studies on actin tyrosine phosphorylation and actin polymerization. The inhibitors of tyrosine phosphorylation inhibit actin tyrosine phosphorylation and polymerization, whereas enhancers of tyrosine phosphorylation stimulate F‐actin formation and tyrosine phosphorylation. These observations suggest that the tyrosine phosphorylation regulates the actin polymerization, and both are coupled processes during capacitation of buffalo spermatozoa.  相似文献   

Role of crop diversification and integrated nutrient management in resilience of soil fertility under rice-wheat cropping system     

SN Sharma  SK Sharma 《Archives of Agronomy and Soil Science》2013,59(3):345-352

A field study conducted for two crop cycles of five cropping systems supplied with six nutrient combinations at the Indian Agricultural Research Institute, New Delhi indicated that the cropping systems having a legume increased organic C content over initial level by 0.02?–?0.05%, available N by 3.5?–?14.1?kg ha^???1, whereas the rice-wheat cropping system resulted in a reduction in organic C and available N over initial level by 0.05% and 1.5?kg ha^???1, respectively after 2 years of study. Rice-potato-mungbean cropping system resulted in a negative balance of available P and rice-clover cropping system had a negative balance of both available P and available K content in soil and thus call for adequate P and K fertilization. Application of P and K helped in building up their content in soil; NPK?+?FYM showed the highest increase in organic C, available N, available P and available K content in soil. These results suggest the inclusion of a legume in a cropping system for maintaining organic C and available N in soil and adequate P and K fertilization for arresting the depletion of available P and K content in soil. Integrated nutrient management is one of the best methods for resilience of soil fertility under rice-wheat cropping system.  相似文献   

Bru1 gene and potential alternative sources of resistance to sugarcane brown rust disease     

Josefina Racedo  María F. Perera  Romina Bertani  Claudia Funes  Victoria González  María I. Cuenya  Angélique D′Hont  Björn Welin  Atilio P. Castagnaro 《Euphytica》2013,191(3):429-436

Brown rust, caused by the fungus Puccinia melanocephala, is responsible for important yield losses in sugarcane production globally and it is therefore an important objective to introduce resistance to this disease in breeding programs. A major gene, Bru1, has been shown to confer resistance to P. melanocephala strains from different parts of the world and two molecular markers, R12H16 and 9O20-F4, closely associated to this gene have been previously reported. The usefulness of these molecular diagnostic markers in order to predict a rust resistant phenotype under natural high pressure inoculums conditions was analyzed. A total of 129 sugarcane accessions were evaluated under field infection for resistance or susceptibility to brown rust and subsequently screened for presence or absence of the two Bru1 diagnostic markers. A total of 49 genotypes (38 %) were phenotyped as resistant to brown rust but only eight (16.3 %) of them were harboring the Bru1 gene. To determine overall frequency of the Bru1 in the local sugarcane germplasm collection, 190 additional genotypes were examined. Presence of Bru1, as determined by the diagnostic markers, was detected in only 7 % of the genotypes evaluated. In conclusion, Bru1 diagnostic markers enable positive selection for brown rust resistance in sugarcane and moreover allowed detecting at least one additional source(s) of resistance. Interestingly, whilst only little genetic variability of rust resistance independent of Bru1 has been reported previously, this alternative genetic resource(s) found in our local germplasm constitutes the predominant one and should be helpful in order to amplify the narrow genetic basis for brown rust resistance in sugarcane.  相似文献   

Cryopreservation of Zona‐Free Cloned Buffalo (Bubalus Bubalis) Embryos: Slow Freezing vs Open‐Pulled Straw Vitrification     

K Sirisha  NL Selokar  M Saini  P Palta  RS Manik  MS Chauhan  SK Singla 《Reproduction in domestic animals》2013,48(4):538-544

This study was carried out to compare the post‐thaw cryosurvival rate and the level of apoptosis in vitro produced zona‐free cloned buffalo blastocysts subjected to slow freezing or vitrification in open‐pulled straws (OPS). Zona‐free cloned embryos produced by handmade cloning were divided into two groups and were cryopreserved either by slow freezing or by vitrification in OPS. Cryosurvival of blastocysts was determined by their re‐expansion rate following post‐thaw culture for 22–24 h. The post‐thaw re‐expansion rate was significantly (p < 0.05) higher following vitrification in OPS (71.2 ± 2.3%) compared with that after slow freezing (41.6 ± 4.8%). For examining embryo quality, the level of apoptosis in day 8 frozen‐thawed blastocysts was determined by TUNEL staining. The total cell number was not significantly different among the control non‐cryopreserved cloned embryos (422.6 ± 67.8) and those cryopreserved by slow freezing (376.4 ± 29.3) or vitrification in OPS (422.8 ± 36.2). However, the apoptotic index, which was similar for embryos subjected to slow freezing (14.8 ± 2.0) or OPS vitrification (13.3 ± 1.8), was significantly (p < 0.05) higher than that for the control non‐cryopreserved cloned embryos (3.4 ± 0.6). In conclusion, the results of this study demonstrate that vitrification in OPS is better than slow freezing for the cryopreservation of zona‐free cloned buffalo blastocysts because it offers a much higher cryosurvival rate.  相似文献   

Effect of Physiologically Relevant Heat Shock on Development,Apoptosis and Expression of Some Genes in Buffalo (Bubalus bubalis) Embryos Produced In Vitro     

A Yadav  KP Singh  MK Singh  N Saini  P Palta  RS Manik  SK Singla  RC Upadhyay  MS Chauhan 《Reproduction in domestic animals》2013,48(5):858-865

For investigating the effects of physiologically relevant heat shock, buffalo oocytes/embryos were cultured at 38.5°C (control) or were exposed to 39.5°C (Group II) or 40.5°C (Group III) for 2 h once every day throughout in vitro maturation (IVM), fertilization (IVF) and culture (IVC). Percentage of oocytes that developed to 8‐cell, 16‐cell or blastocyst stage was lower (p < 0.05) and the number of apoptotic nuclei was higher (p < 0.05) for Group III > Group II > controls. At both 8–16‐cell and blastocyst stages, relative mRNA abundance of stress‐related genes HSP 70.1 and HSP 70.2 and pro‐apoptotic genes CASPASE‐3, BID and BAX was higher (p < 0.05) in Groups III and II than that in controls with the exception of stress‐related gene HSF1. Expression level of anti‐apoptotic genes BCL‐XL and MCL‐1 was also higher (p < 0.05) in Groups III and II than that in controls at both 8–16‐cell and blastocyst stages. Among the genes related to embryonic development, at 8–16‐cell stage, the expression level of GDF9 was higher (p < 0.05) in Group III than that in controls, whereas that of GLUT1, ZAR1 and BMP15 was not significantly different among the three groups. At the blastocyst stage, relative mRNA abundance of GLUT1 and GDF9 was higher (p < 0.05) in Group II than that in controls, whereas that of ZAR‐1 and BMP15 was not affected. The results of this study demonstrate that exposure of buffalo oocytes and embryos to elevated temperatures for duration of time that is physiologically relevant severely compromises their developmental competence, increases apoptosis and affects stress‐, apoptosis‐ and development‐related genes.  相似文献   

Buffalo (Bubalus bubalis) ES Cell–Like Cells are Capable of In Vitro Skeletal Myogenic Differentiation     

MK Singh  KP Singh  D Kumar  RA Shah  T Anand  MS Chauhan  RS Manik  SK Singla  P Palta 《Reproduction in domestic animals》2013,48(2):284-291

When buffalo embryonic stem (ES) cell–like cells that expressed surface markers SSEA‐4, TRA‐1‐60, TRA‐1‐81, CD9 and CD90 and intracellular markers OCT4, SOX2 and FOXD3, as shown by immunofluorescence, and that expressed REX‐1 and NUCLEOSTEMIN as confirmed by RT‐PCR, were subjected to suspension culture in hanging drops in absence of LIF and buffalo foetal fibroblast feeder layer support, they differentiated to form three‐dimensional embryoid bodies (EBs). Of 231 EBs examined on Day 3 of suspension culture, 141 (61.3 ± 3.09%) were of compact type, whereas 90 (38.4 ± 3.12%) were of cystic type. The cells obtained from EBs were found to express NF‐68 and NESTIN (ectodermal lineage), BMP‐4 and α‐skeletal actin (mesodermal lineage), and α‐fetoprotein, GATA‐4 and HNF‐4 (endodermal lineage). When these EBs were cultured on gelatin‐coated dishes, they spontaneously differentiated to several cell types such as epithelial‐ and neuron‐like cells. When EBs were cultured in the presence of 1 or 2% DMSO or 10^?8 m or 10^?7 m retinoic acid for 25 days, ES cells could be directed to form muscle cell–like cells, the identity of which was confirmed by expression of α‐actinin by immunofluorescence and of MYF‐5, MYOD and MYOGENIN genes by RT‐PCR. MYOD was first detected on Day 10 in both treatment groups and on Day 15 in controls, whereas MYOGENIN was first detected on Day 10, Day 15 and Day 25 in the presence of retinoic acid, in the presence of DMSO and in controls, respectively. The present study demonstrates the ability of buffalo ES cell–like cells to undergo directed differentiation to cells of skeletal myogenic lineage.  相似文献