Differential Expression of Xylanases and Endoglucanases in the Hybrid Derived from Intergeneric Protoplast Fusion between a Cellulomonas sp. and Bacillus subtilis

A stable hybrid obtained by protoplast fusion between a Cellulomonas sp. and Bacillus subtilis exhibits an altered pattern of enzyme induction with different cellulosic substrates. Unlike in the Cellulomonas sp., xylanase was induced in the hybrid organism specifically by xylan, and endoglucanase was induced by carboxymethyl cellulose. The amount and specific activity of xylanase produced by the hybrid were more than those produced by the Cellulomonas sp. β-Glucosidase which is cell bound or intracellular in the Cellulomonas sp. was secreted by the hybrid organism, and relative amounts of extracellular β-glucosidase were high. Furthermore, this extracellular β-glucosidase activity was dependent on the nature of the cellulosic substrate. Endoglucanases synthesized in the hybrid differed in their electrophoretic mobilities as compared with the parental enzymes

Optical detection of antibody using silica-silver core-shell particles

Nearly monodispersed spherical particles of silica were synthesized and coated with thin layer of silver nanoparticles. Silver coated silica particles, forming core-shell particles exhibited a strong surface plasmon resonance peak at 453 nm. A very small amount (20 μg) of rabbit immunoglobulin in core-shell particle solution results in to a marked shift in surface plasmon resonance. Addition of 20 μg quantity of goat anti rabbit antibodies results in to a red shift of surface plasmon resonance to 494 nm. This demonstrates that silver coated silica particles are sensitive probes for rapid antibody-anti antibody kind of interaction investigations. Fourier transform infra red spectroscopy and scanning electron microscopy have been used to interpret the optical extinction spectroscopy results

<span style="font-size: 21.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman","serif"">Highly-substrate active isoenzyme acetylcholinesterase-II, in rosy eye mutant of <i><span style="font-size:21.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman","serif"">Aedes aegypti </span></i><span style="font-size:21.0pt;mso-bidi-font-size:14.0pt; font-family:"Times New Roman","serif"">mosquito </span></span>

807-810<span style="font-size: 15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">Insecticide bioassays were carried out on larvae and adults of rosy eye mutant and wildtype strains of A. <span style="font-size:15.5pt;mso-bidi-font-size:8.5pt; font-family:" times="" new="" roman","serif""="">aegypti. Both the strains were equally susceptible to DDT, malathion and deltamethrin. Biochemical assays showed an increase in acetylcholinesterase enzyme (AChE) activity in all the stages of mutant strain with both the substrates i.e. acetylthiocholine iodide and S-butyrylthiocholine iodide. However, there was no difference in the percent inhibition of enzyme activity with propoxur in these two strains. Polyacrylamide gel electrophoresis performed in native conditions on the homogenates of adults of rosy eye mosquitoes showed that AChE-II allele was highly active with the substrate acetylthiocholine iodide as compared to wildtype strain. Frequency of the highly active AChE-II allele in the mutant strain was about 68%, whereas it was about 5% in the wildtype strain. </span

First report on IS elements of <i>Shigella flexneri</i> 1a— A common Indian isolate

199-203Shigella species are non-sporulating, Gram negative, facultative anaerobes. IS (insertion sequence) elements are the major cause of the dynamics of Sf301 chromosome and due to IS-mediated DNA rearrangements and formation of pseudogenes, the Shigella spp. became highly specific human pathogens with variable epidemiological and pathological features. Nucleotide sequence analysis of S. flexneri 1a genomic DNA was performed through Big dye terminator chemistry using ABI 3730 48 capillary DNA analyzer. In total, 60 kb data in form of contigs were analyzed by homology search using various bioinformatics tools. IS elements were identified using nucleotide blast at NCBI as well as the Is finder. Eight different IS elements were identified, which were present in different copy number. A new IS element ISEhe3 was identified, which belonged to family IS3. ISEhe3 was found absent in S. flexneri 2a 301, but it was present in 2457T strain. Amongst the IS elements identified, IS2, IS3 and IS600 elements showed identity with SHI2 Shigella pathogenicity island. The presence of large numbers of IS-elements in the <i style="mso-bidi-font-style: normal">Shigella genomes is likely the major cause of many of the genome rearrangements. Further investigations on IS elements will help to study genome dynamics and rearrangement of S. flexneri 1a strain. </span

Serratia odorifera a midgut inhabitant of Aedes aegypti mosquito enhances its susceptibility to dengue-2 virus.

Mosquito midgut plays a crucial role in its vector susceptibility and pathogen interaction. Identification of the sustainable microflora of the midgut environment can therefore help in evaluating its contribution in mosquito-pathogen interaction and in turn vector competence. To understand the bacterial diversity in the midgut of Aedes aegypti mosquitoes, we conducted a screening study of the gut microbes of these mosquitoes which were either collected from fields or reared in the laboratory "culture-dependent" approach. This work demonstrated that the microbial flora of larvae and adult Ae. aegypti midgut is complex and is dominated by gram negative proteobacteria. Serratia odorifera was found to be stably associated in the midguts of field collected and laboratory reared larvae and adult females. The potential influence of this sustainable gut microbe on DENV-2 susceptibility of this vector was evaluated by co-feeding S. odorifera with DENV-2 to adult Ae. aegypti females (free of gut flora). The observations revealed that the viral susceptibility of these Aedes females enhanced significantly as compared to solely dengue-2 fed and another gut inhabitant, Microbacterium oxydans co-fed females. Based on the results of this study we proposed that the enhancement in the DENV-2 susceptibility of Ae. aegypti females was due to blocking of prohibitin molecule present on the midgut surface of these females by the polypeptide of gut inhabitant S. odorifera

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">Enhanced esterase activity in salivary gland and midgut of <i>Aedes aegypti</i> mosquito infected with dengue-2 virus</span>

91-93<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">Mosquitoes were infected by intrathoracic inoculation. About 95% head squashes were positive for dengue virus antigen on the 15th post infection day (PID). Esterase activity was determined in the homogenates prepared from the salivary glands and midguts on different PIDs of dengue virus inoculated and control mosquitoes showed that it was consistently higher in the virus- infected batches.</span

Serratia odorifera mediated enhancement in susceptibility of Aedes aegypti for chikungunya virus

Background & objectives: The susceptibility of the mosquito to the invading pathogen is predominantly dictated by the complex interactions between the mosquito midgut and the surface proteins of the invading pathogen. It is well documented that the midgut microbiota plays an important role in determining the susceptibility of the mosquito to the pathogen. In the present study, we investigated the influence of Serratia odorifera, an endogenous cultivable midgut inhabitant of Aedes aegypti on the chikungunya virus (CHIKV) susceptibility to this mosquito. Methods: Ae. aegypti females free of gutflora were co-fed with CHIKV and either of the two midgut inhabitants namely, S. odorifeara and Microbacterium oxydans. CHIKV dissemination was checked on 10 th day post feeding (DPF) using indirect immunoflurescence assay and plaque assay. CHIKV interacting proteins of the mosquito midgut were identified using virus overlay protein binding assay and MALDI TOF/TOF analysis. Results: The observations revealed that co-feeding of S. odorifera with CHIKV significantly enhanced the CHIKV susceptibility in adult Ae. aegypti, as compared to the mosquitoes fed with CHIKV alone and CHIKV co-fed with another midgut inhabitant, M. oxydans. Virus overlay protein binding assay (VOPBA) results revealed that porin and heat shock protein (HSP60) of Ae. aegypti midgut brush border membrane fraction interacted with CHIKV. Interpretation & conclusions: The results of this study indicated that the enhancement in the CHIKV susceptibility of Ae. aegypti females was due to the suppression of immune response of Ae. aegypti as a result of the interaction between S. odorifera P40 protein and porin on the gut membrane