Virulence attenuation of a UDP-galactose/<Emphasis Type="Italic">N</Emphasis>-acetylglucosamine β1,4 galactosyltransferase expressing <Emphasis Type="Italic">Leishmania donovani</Emphasis> promastigote

Protozoan parasites of the genus Leishmania are the causative agent of leishmaniasis, a disease whose manifestations in humans range from mild cutaneous lesions to fatal visceral infections. Human visceral leishmaniasis is caused by Leishmania donovani. Long-term culture in vitro leads to the attenuation of the parasite. This loss of parasite virulence is associated with the expression of a developmentally regulated UDP-Galactose/N-acetylglucosamine beta 1-4 galactosyltransferase and galactose terminal glycoconjugates as determined by their agglutination with the pea nut agglutinin (PNA). Thus, all promastigotes passaged for more than 11 times were 100% agglutinated with PNA, and represent a homogeneous population of avirulent parasites. Identical concentrations of PNA failed to agglutinate promastigotes passaged for < or =5 times. These PNA(-) promastigotes were virulent. Promastigotes passaged from 5 to 10 times showed a mixed population. The identity of populations defined by virulence and PNA agglutination was confirmed by isolating PNA(+) avirulent and PNA(-) virulent clones from the 7th passage promastigotes. Only the PNA(+) clones triggered macrophage microbicidal activity. The PNA(+) clones lacked lipophosphoglycan. Intravenous administration of [(14)C] galactose-labeled parasite in BALB/c mice resulted in rapid clearance of the parasite from blood with a concomitant accumulation in the liver. By enzymatic assay and RT-PCR we have shown the association of a UDP-Galactose/N-acetylglucosamine beta1,4 galactosyltransferase with only the attenuated clones. By immunofluorescence we demonstrated that the enzyme is located in the Golgi apparatus. By western blot analysis and SDS-PAGE of the affinity-purified protein, we have been able to identify a 29 KDa galactose terminal protein from the avirulent clones.     

Microsatellite and Mitochondrial Diversity Analysis of Native Pigs of Indo-Burma Biodiversity Hotspot

Assessment of genetic diversity in indigenous animals is an important and essential task for animal genetic improvement studies as well as conservation decision-making. The genetic diversity and evolutionary relationships among geographically and phenotypically distinct three pig breeds/types native to Indo-Burma and Eastern Himalayan global biodiversity hotspots were determined by genotyping with a panel of 22 ISAG recommended microsatellite loci as well as sequencing partial MTRNR1gene. The mean number of alleles per locus, effective number of alleles and observed heterozygosity were found to be 11.27 ± 0.85, 5.29 ± 0.34, and 0.795 ± 0.01, respectively. The moderate F_ST value (0.115 ± 0.01) indicated a fair degree of genetic differentiation among the native breeds. The Nei’s unbiased genetic identity estimates indicated less genetic distance (0.2909) between Niang Megha and Tenyi Vo pigs than the both individually with Ghoongroo breed. The divergence time was also estimated from the microsatellite analysis. Analysis of MTRNR1gene revealed distinct clustering of native Indian pigs with Chinese pigs over European pigs. The study revealed the abundance of genetic variation within native Indian pigs and their relationships as well as genetic distances.     

Understanding the role of climatic and environmental variables in gonadal maturation and spawning periodicity of spotted snakehead, <Emphasis Type="Italic">Channa punctata</Emphasis> (Bloch, 1793) in a tropical floodplain wetland,India

Temperature and seasonal rainfall along with other environmental variables are important in regulating the reproductive cycles in teleost fishes. Certain environmental variables may act as cues for reproduction and changes in these may affect seasonality and success of reproduction, as fishes are known to integrate their physiological functions with environmental cycles. Wetlands are sensitive to climate change due to their shallow and confined nature. Since wetlands are important spawning and nursery grounds for many fishes, changes in the environmental variables may have direct consequences for the spawning and survival of fish. In the present study, we have assessed climatic and water chemistry variables capable of influencing seasonality in environmental variables as well as gonadal maturation of spotted snakehead Channa punctata, to predict threshold values of Gonado Somatic Index in females and a favourable range of identified climatic and water chemistry variables for breeding success. Among the climatic and water chemistry variables studied, seasonal variation in rainfall was found to have the most profound effect on gonadal maturation and breeding in C. punctata, followed by water temperature. The favourable range of rainfall obtained varied between 800 mm to 1400 mm, corresponding to the water temperature range between 29 °C and 31 °C. An overall significant warming trend with a reduction in total rainfall has been observed with changes in seasonal trends in temperature and rainfall in the study area. The rainfall being the major climatic factors influencing water chemistry in the wetlands during the spawning season, changes in rainfall pattern may influence breeding periodicity of C. punctata in wetlands in climate change scenario.     

Nanofibrous nonmulberry silk/PVA scaffold for osteoinduction and osseointegration

Poly‐vinyl alcohol and nonmulberry tasar silk fibroin of Antheraea mylitta are blended to fabricate nanofibrous scaffolds for bone regeneration. Nanofibrous matrices are prepared by electrospinning the equal volume ratio blends of silk fibroin (2 and 4 wt%) with poly‐vinyl alcohol solution (10 wt%) and designated as 2SF/PVA and 4SF/PVA, respectively with average nanofiber diameters of 177 ± 13 nm (2SF/PVA) and 193 ± 17 nm (4SF/PVA). Fourier transform infrared spectroscopy confirms retention of the secondary structure of fibroin in blends indicating the structural stability of neo‐matrix. Both thermal stability and contact angle of the blends decrease with increasing fibroin percentage. Conversely, fibroin imparts mechanical stability to the blends; greater tensile strength is observed with increasing fibroin concentration. Blended scaffolds are biodegradable and support well the neo‐bone matrix synthesis by human osteoblast like cells. The findings indicate the potentiality of nanofibrous scaffolds of nonmulberry fibroin as bone scaffolding material. © 2014 Wiley Periodicals, Inc. Biopolymers 103: 271–284, 2015.     

Nomenclatural notes and typification of names in the mangrove tribe Rhizophoreae (Rhizophoraceae) of India

The nomenclatures of the taxa of the mangrove Rhizophoraceae of India have been scrutinized and 20 names are lectotypified or neotypified. In addition, the holotypes of some names are located for the first time with clarifications provided. Since natural hybridization is common in Rhizophoraceae, its consequences for the correct application of names is also briefly discussed.     

Interneuronal mechanisms for learning-induced switch in a sensory response that anticipates changes in behavioral outcomes

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