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Chitinase Genes (chitinase + gene)

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Life Sciences	100%

Selected Abstracts

Effect of environmental factors on expression and activity of chitinase genes of vibrios with special reference to Vibrio cholerae

JOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007
R. Bhowmick
Abstract Aims:, The aim of this study was to investigate the distribution and inducibility of chitinase genes in vibrios and the effect of environmental factors on the expression level and activity of chitinase genes in Vibrio cholerae strains. Methods and Results:, Chitin agar plate assays showed that V. cholerae strains were more chitinolytic than non- cholerae vibrios. All of the identified or putative chitinase genes were expressed in V. cholerae (four strains) but not in non- cholerae vibrios (seven species/strains) under standard laboratory growth conditions. In non- cholerae vibrios, these genes were induced by chitin, its monomer N -acetyl- d -glucosamine and on exposure to rabbit intestine, while in V. cholerae strains, these genes showed significant variation in expression levels. To study the effects of environmental factors on the expression and activity of chitinase genes in V. cholerae, bacteria were cultured in different pH, temperature, sodium chloride and nutrients. RT-PCR analysis showed that lower temperatures and higher pH, salinity and nutrition favoured expression of these genes, while their activity increased under higher nutrition content and salinity. Conclusions:, Chitinase genes are distributed in all the relatively small number of strains studied here, and biotic and abiotic factors have significant role in the induction, expression level and activity of this gene family in vibrios. Significance and Impact of the Study:, Chitinases have important applications especially in recycling of chitin. Vibrios can be used as chitinolytic agents, using suitable culture conditions that maximize the expression and activity of these genes. [source]

Adverse effect of the chitinolytic enzyme PjCHI-1 in transgenic tomato on egg mass production and embryonic development of Meloidogyne incognita

PLANT PATHOLOGY, Issue 5 2010
Y.-L. Chan
A novel chitinase gene (PjCHI-1) isolated from Paecilomyces javanicus, a non-nematophagous fungus, and driven by a CaMV35S promoter, was delivered into CLN2468D, a heat-tolerant cultivar of tomato (Solanum lycopersicum). T1 tomato plants exhibited high endochitinase activity and reduced numbers of eggs and egg masses when infected with the root-knot nematode (RKN) Meloidogyne incognita. The eggs found in transgenic tomato had lower shell chitin contents than eggs collected from control plants. Egg masses from transgenic plants exhibited higher chitinase activity than those from control plants. Moreover, only 30% of eggs from transgenic plants were able to develop to the multi-cell/J1 stage, compared with more than 96% from control plants. The present study demonstrated that the expression of the PjCHI-1 chitinase gene can effectively reduce the production of egg masses and repress the embryonic development of M. incognita, presenting the possibility of a novel agro-biotechnological strategy for preventing crop damage by RKN. [source]

Bacillus pumilus SG2 isolated from saline conditions produces and secretes two chitinases

JOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2007
G. Ahmadian
Abstract Aims: Isolation and characterization of chitinases from a halotolerant Bacillus pumilus. Methods and Results: Bacillus pumilus strain SG2 was isolated from saline conditions. It is able to produce chitinase activity at high salt concentration. SDS-PAGE analysis of the B. pumilus SG2 culture supernatant showed two major bands that were induced by chitin. The amino acid sequence of the two proteins, designated ChiS and ChiL, showed a high homology with the chitinase of B. subtilis CHU26, and chitinase A of B. licheniformis, respectively. N -terminal signal peptide of both proteins was also determined. The molecular weight and isoelectric point of the chitinases were determined to be 63 and 74 kDa, and 4·5 and 5·1, for ChiS and ChiL respectively. The genes encoding for both chitinases were isolated and their sequence determined. The regulation of the chitinase genes is under the control of the catabolite repression system. Conclusions: Secreted chitinase genes and their flanking region on the genome of B. pumilus SG2 have been identified and sequenced. Significance and Impact of the Study: This is the first report of a multiple chitinases-producing B. pumilus halotolerant strain. We have identified two chitinases by using a reverse genetics approach. The chitinases show resistance to salt. [source]

Effect of environmental factors on expression and activity of chitinase genes of vibrios with special reference to Vibrio cholerae

Graft transmission of induced and spontaneous post-transcriptional silencing of chitinase genes

THE PLANT JOURNAL, Issue 5 2001
Patrice Crété
Summary Sense and antisense tobacco chitinase (CHN) transgenes, Luciferase-CHN transcriptional fusions, and promoterless CHN cDNAs were introduced biolistically into CHN transformants of tobacco that never exhibit spontaneous gene silencing. All of the constructs tested induced systemic silencing of the resident CHN transgene and endogenes. Nuclear run-on transcription assays showed that local introduction of additional gene copies triggers systemic post-transcriptional gene silencing (PTGS). Together, this provides evidence that additional transgene copies need not be either highly transcribed or produce sense transcripts to evoke production of systemic PTGS signals. CHN PTGS was transmitted by top grafting, but not by reciprocal grafting of mature stems or the exchange of tissue plugs. Thus, the commonly encountered difficulties in achieving graft-transmission could reflect the method used. Silencing in sense but not antisense transformants was transmitted by grafting to a high-expressing sense CHN scion suggesting that the elaboration of mobile signals may not be an essential feature of antisense-mediated gene silencing. [source]