Variability of the EG95 antigen-coding gene of Echinococcus granulosus in animal and human origin: implications for vaccine development

In the present study, the genetic variability of the EG95 protein-coding gene in several animal and human isolates of Echinococcus granulosus was investigated. A total of 24 isolates collected from cattle, buffalo, sheep, goat, dog and man were amplified by Eg95-coding gene-specific primers. From the generated sequence information, a conceptual amino acid sequence was deduced. Phylogenetically, the Eg95 coding gene belongs to the Eg95-1/Eg95-2/Eg95-3/Eg95-4 cluster. Further confirmation on the maximum composite likelihood analysis revealed that the overall transition/transversion bias was 2.913. This finding indicated thatthere is bias towards transitional and transversional substitution. Using artificial neural networks, a B-cell epitope was predicted on primary sequence information. Stretches of amino acid residues varied between animal and human isolates when hydrophobicity was considered. Flexibility also varied between larval and adult stages of the organism. This observation is important to develop vaccines. However, cytotoxic T-lymphocyte epitopes on primary sequence data remained constant in all isolates. In this study, agretope identification started with hydrophobic amino acids. Amino acids with the same physico-chemical properties were present in the middle. The conformational propensity of the Eg95-coding gene of 156 amino acid residues had α-turns and β-turns, and α-amphipathic regions up to 129, 138–156 and 151–155 residues, respectively. The results indicated potential T-cell antigenic sites. The overall Tajima’s D value was negative (−2.404165), indicative of negative selection pressure.

Molecular appraisal of Indian animal isolates of Echinococcus granulosus.

BACKGROUND & OBJECTIVE: Cystic echinococcosis (CE) has a wide host range and distinct entities, not only reflected phenotypically but also by genotypic variation. Considering this fact, this study was undertaken to characterize the Indian isolates of Echinococcus granulosus to find out difference between Indian cattle, buffalo and sheep isolates on the basis of random amplification of polymorphic DNA (RAPD) PCR and PCR mediated restriction fragment length polymorphism (PCRRFLP) of internal transcribed spacer gene 1 (ITS1). METHODS: A total of 22 isolates of E. granulosus obtained from Indian cattle, buffalo and sheep (December 2004 - November 2005) were analysed by 26 random primers of 8-10 mers. After isolation of protoscoleces from fertile cyst, DNA was extracted, quantified and amplified by random primers. Internal transcribed spacer gene 1 (ITS1) was amplified using specific primer and digested by two restriction enzymes (Msp1 and Rsa1). RESULTS: Of the 26 primers, only two primers (5'ACC TGG ACA C3' and 5' TCA TCC GAG G3') could discriminate cattle, buffalo and sheep isolates collected from eastern part of India. Samples were further analysed by PCR mediated RFLP of internal transcribed spacer gene1 (ITS1) using two restriction enzymes (Msp1 and Rsa1). No ITS1 variants could be detected. INTERPRETATION & CONCLUSION: Our findings showed genotypic variation among Indian animal isolates of E. granulosus on the basis of RAPD fingerprinting.

Individual and combined effect of mercury and manganese on phenol and proline content in leaf and stem of mungbean seedlings.

Mungbean (Vigna radiata L. Wilczelk cv. Pusa Baisakhi seedlings were raised in individual (0, 1, 10, 100 and 1000 ppm) and combined solutions (1 : 1, 10: 1, 1: 0 ppm Hg : Mn) of mercury and manganese for 6 days. Phenol and proline were found to accumulate in leaves in response to treatment with heavy metals. The magnitude of accumulation correlated with concentration of metals. However, a reverse trend was noticed in stem for phenol. Accumulation of phenol in response to heavy metal treatment was organ specific and occurred at higher rate in plant parts, which faced the stress mostly. However, accumulation of proline helped the plant to survive stress situation. In combined solutions, amelioration of mercurial toxicity by manganese was recorded.

Amelioration of mercurial toxicity by manganese. I. A case study in mung bean seedling.

Mercury, a non essential element renders inhibitory effect on many physiological activities of plants even at a low concentration. Plants absorb "Hg" from soil through root system. Manganese, an essential element has been found to counter the inhibitory effect of mercury mostly by preventing it's uptake from soil. Mung bean (Vigna radiata L. Wilczek) cv. Pusa Baisakhi grown in individual (1, 10, 100 and 1000 ppm) solution of Hg and Mn showed varied uptake of these heavy metals. However, in combined solutions (1 : 1, 10 : 1 and 1 : 10 ppm Hg : Mn), mercury uptake was mostly prevented in presence of 10 ppm Mn, indicating it's ameliorating effect.

Impact of cadmium toxicity on leaf area, stomatal frequency, stomatal index and pigment content in mungbean seedlings.

Effect of different concentrations of CdSO4 (10(-4) M, 5 x 10(-4) M and 10(-3) M) on leaf area, stomatal frequency, stomatal index and pigment content in 6 days old mungbean seedlings was studied under laboratory conditions. Except at 10(-4) M CdSO4, leaf area decreased with an increase in the concentration of CdSO4. Stomatal frequency on the leaf surface increased at 5 x 10(-4) M and 10(-3) M CdSO4 in comparison to untreated control. However, reverse was the case for stomatal index. Chlorophyll-a, chlorophyll-b, total chlorophyll, and chlorophyll a/b ratio were increased at 10(-4) M CdSO4, and decreased thereafter with an increase in the concentration of Cd2+. Possible reasons for the stimulatory effect at low concentrations and inhibitory effect with higher concentrations are discussed.