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Bioactive endophytic streptomycetes from the Malay Peninsula 总被引:1,自引:0,他引:1
Zin NM Sarmin NI Ghadin N Basri DF Sidik NM Hess WM Strobel GA 《FEMS microbiology letters》2007,274(1):83-88
Three novel endophytic streptomycetes have been isolated and characterized from plants with ethnobotanical uses on the Malay Peninsula including: Thottea grandiflora (family -Aristolochiaceae), Polyalthia spp. (family -Annonaceae), and Mapania sp. (family -Cyperaceae). Each isolate, as studied by scanning electron microscopy, has small hyphae, and produces typical barrel-shaped spores arising by hyphal fragmentation. Interestingly, although none has any detectable antibacterial killing properties, each has demonstrable killing activity against one or more pathogenic fungi including organisms such as Phytophthora erythroseptica, Pythium ultimum, Sclerotinia sclerotiorum, Mycosphaerella fijiensis and Rhizoctonia solani. Molecular biological studies on the rRNA gene sequence of each isolate revealed that it is distinct from all other genetic accessions of streptomyectes in GenBank, and each bears some genetic similarity to other streptomycetes. The bioactivity of each microbe was extractable in various organic solvents. 相似文献
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Mohammad Murshid Alam Amena Aktar Sadia Afrin Mohammad Arif Rahman Sarmin Aktar Taher Uddin M. Arifur Rahman Deena Al Mahbuba Fahima Chowdhury Ashraful Islam Khan Taufiqur Rahman Bhuiyan Yasmin Ara Begum Edward T. Ryan Stephen B. Calderwood Ann-Mari Svennerholm Firdausi Qadri 《PLoS neglected tropical diseases》2014,8(4)
Background
Multiple infections with diverse enterotoxigenic E. coli (ETEC) strains lead to broad spectrum protection against ETEC diarrhea. However, the precise mechanism of protection against ETEC infection is still unknown. Therefore, memory B cell responses and affinity maturation of antibodies to the specific ETEC antigens might be important to understand the mechanism of protection.Methodology
In this study, we investigated the heat labile toxin B subunit (LTB) and colonization factor antigens (CFA/I and CS6) specific IgA and IgG memory B cell responses in Bangladeshi adults (n = 52) who were infected with ETEC. We also investigated the avidity of IgA and IgG antibodies that developed after infection to these antigens.Principal Findings
Patients infected with ETEC expressing LT or LT+heat stable toxin (ST) and CFA/I group or CS6 colonization factors developed LTB, CFA/I or CS6 specific memory B cell responses at day 30 after infection. Similarly, these patients developed high avidity IgA and IgG antibodies to LTB, CFA/I or CS6 at day 7 that remained significantly elevated at day 30 when compared to the avidity of these specific antibodies at the acute stage of infection (day 2). The memory B cell responses, antibody avidity and other immune responses to CFA/I not only developed in patients infected with ETEC expressing CFA/I but also in those infected with ETEC expressing CFA/I cross-reacting epitopes. We also detected a significant positive correlation of LTB, CFA/I and CS6 specific memory B cell responses with the corresponding increase in antibody avidity.Conclusion
This study demonstrates that natural infection with ETEC induces memory B cells and high avidity antibodies to LTB and colonization factor CFA/I and CS6 antigens that could mediate anamnestic responses on re-exposure to ETEC and may help in understanding the requirements to design an effective vaccination strategies. 相似文献4.
Faruk Mohammad Omar Rahman Md. Sahidur Jannat Sumiya Nur Arafat Yasin Islam Kamrul Akhter Sarmin 《Aerobiologia》2022,38(3):277-286
Aerobiologia - The coronavirus disease (COVID-19) caused an unprecedented loss of life with colossal social and economic fallout over 237 countries and territories worldwide. Environmental... 相似文献
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