排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
Martin Bundi Mohammad Monir Shah Eric Odoyo Cyrus Kathiiko Ernest Wandera Gabriel Miring'u Sora Guyo Daniel Langat Kouichi Morita Yoshio Ichinose 《Microbiology and immunology》2019,63(9):350-358
Kenya is endemic for cholera with different waves of outbreaks having been documented since 1971. In recent years, new variants of Vibrio cholerae O1 have emerged and have replaced most of the traditional El Tor biotype globally. These strains also appear to have increased virulence, and it is important to describe and document their phenotypic and genotypic traits. This study characterized 146 V. cholerae O1 isolates from cholera outbreaks that occurred in Kenya between 1975 and 2017. Our study reports that the 1975–1984 strains had typical classical or El Tor biotype characters. New variants of V. cholerae O1 having traits of both classical and El Tor biotypes were observed from 2007 with all strains isolated between 2015 and 2017 being sensitive to polymyxin B and carrying both classical and El Tor type ctxB. All strains were resistant to Phage IV and harbored rstR, rtxC, hlyA, rtxA and tcpA genes specific for El Tor biotype indicating that the strains had an El Tor backbone. Pulsed field gel electrophoresis (PFGE) genotyping differentiated the isolates into 14 pulsotypes. The clustering also corresponded with the year of isolation signifying that the cholera outbreaks occurred as separate waves of different genetic fingerprints exhibiting different genotypic and phenotypic characteristics. The emergence and prevalence of V. cholerae O1 strains carrying El Tor type and classical type ctxB in Kenya are reported. These strains have replaced the typical El Tor biotype in Kenya and are potentially more virulent and easily transmitted within the population. 相似文献
2.
Hydrobiologia - We investigated the effect of CO2 and nutrient enrichment on competition between two free-floating fern species that co-occur in south-eastern Australia—native Azolla... 相似文献
3.
Olushayo Oluseun Olu Richard Lako Sudhir Bunga Kibebu Berta Matthew Kol Patrick Otim Ramadan Caroline Ryan Ifeanyi Udenweze Argata Guracha Guyo Ishata Conteh Qudsia Huda Malick Gai Dina Saulo Heather Papowitz Henry John Gray Alex Chimbaru Kencho Wangdi Steven M. Grube Beth Tippett Barr Joseph Francis Wamala 《PLoS neglected tropical diseases》2020,14(11)
4.
Hydrobiologia - Ongoing global environmental changes such as rising atmospheric CO2 concentration ([CO2]) and eutrophication are in some parts thought to facilitate exotic plant species invasions... 相似文献
5.
Upenyu Guyo Nyasha Matewere Kaina Matina Benias C. Nyamunda Mambo Moyo 《Bioremediation Journal》2017,21(3-4):163-175
Poly(methyl methacrylate)–grafted Hyparrhenia hirta (PMMA-g-Hh) biopolymer was prepared through radical polymerization using potassium persulfate (KPS) and applied in adsorption of methyl red from colored solutions. Solvent amount, initiator concentration, monomer concentration, temperature, and reaction time were the reaction parameters investigated for grafting. The biopolymer was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction spectroscopy (XRD). The adsorption process was investigated with respect to pH, contact time, initial concentration, adsorbent dosage, and temperature. The optimum adsorption parameters were pH 6, contact time 90 min, adsorbent dosage 0.6 g, and initial concentration 50 mg/L. The Langmuir adsorption model best fitted the adsorption process, with maximum adsorption capacities of 19.95, 6.89, and 4.02 mg/g at adsorbent dosages of 0.2, 0.6, and 1.0 g, respectively. The pseudo-second-order model described the kinetics data better. The adsorption process was physical, spontaneous, and endothermic. The adsorbent was still active after 10 adsorption-desorption cycles, showing its suitability for use in colored solutions treatment. 相似文献
1