Anaerobiosis revisited: growth of Saccharomyces cerevisiae under extremely low oxygen availability

The budding yeast Saccharomyces cerevisiae plays an important role in biotechnological applications, ranging from fuel ethanol to recombinant protein production. It is also a model organism for studies on cell physiology and genetic regulation. Its ability to grow under anaerobic conditions is of interest in many industrial applications. Unlike industrial bioreactors with their low surface area relative to volume, ensuring a complete anaerobic atmosphere during microbial cultivations in the laboratory is rather difficult. Tiny amounts of O2 that enter the system can vastly influence product yields and microbial physiology. A common procedure in the laboratory is to sparge the culture vessel with ultrapure N2 gas; together with the use of butyl rubber stoppers and norprene tubing, O2 diffusion into the system can be strongly minimized. With insights from some studies conducted in our laboratory, we explore the question ‘how anaerobic is anaerobiosis?’. We briefly discuss the role of O2 in non-respiratory pathways in S. cerevisiae and provide a systematic survey of the attempts made thus far to cultivate yeast under anaerobic conditions. We conclude that very few data exist on the physiology of S. cerevisiae under anaerobiosis in the absence of the anaerobic growth factors ergosterol and unsaturated fatty acids. Anaerobicity should be treated as a relative condition since complete anaerobiosis is hardly achievable in the laboratory. Ideally, researchers should provide all the details of their anaerobic set-up, to ensure reproducibility of results among different laboratories. A correction to this article is available online at http://eprints.whiterose.ac.uk/131930/ https://doi.org/10.1007/s00253-018-9036-

Human Papillomavirus Vaccination Among Young Men Who Have Sex With Men and Transgender Women in 2 US Cities, 2012–2014

BackgroundSince 2011, in the United States, quadrivalent human papillomavirus (HPV) vaccine has been recommended for boys aged 11 to 12 years, men through age 21, and men who have sex with men (MSM) through age 26. We assessed HPV vaccination coverage and factors associated with vaccination among young MSM (YMSM) and transgender women (TGW) in 2 cities.MethodsDuring 2012-2014, 808 YMSM and TGW aged 18 to 26 years reported vaccination status in a self-administered computerized questionnaire at 3 sexually transmitted disease (STD) clinics in Los Angeles and Chicago. Associations with HPV vaccination were assessed using bivariate and multivariable models to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).ResultsFew of the diverse participants (Hispanic/Latino, 38.0%; white, 27.0%; and black/African American, 17.9%) reported receiving 1 or more HPV vaccine doses (n = 111 [13.7%]) and even fewer reported 3 doses (n = 37 [4.6%]). A multivariable model found associations between vaccination and having a 4-year college degree or higher (aOR, 2.83; CI, 1.55-5.17) and self-reported STDs (aOR, 1.21; CI, 1.03-1.42). In a model including recommendation variables, the strongest predictor of vaccination was a health care provider recommendation (aOR, 11.85; CI, 6.70-20.98).ConclusionsHuman papillomavirus vaccination coverage was low among YMSM and TGW in this 2-US city study. Our findings suggest further efforts are needed to reach YMSM seeking care in STD clinics, increase strong recommendations from health care providers, and integrate HPV vaccination with other clinical services such as STD testing

Vaccine Effectiveness Against Prevalent Anal and Oral Human Papillomavirus Infection Among Men Who Have Sex With Men-United States, 2016-2018.

BackgroundIn the United States, human papillomavirus (HPV) vaccination has been recommended for young adult men who have sex with men (MSM) since 2011.MethodsThe Vaccine Impact in Men study surveyed MSM and transgender women aged 18-26 years in 3 US cities during 2016-2018. Self-collected anal swab and oral rinse specimens were assessed for 37 types of HPV. We compared HPV prevalence among vaccinated and unvaccinated participants and determined adjusted prevalence ratios (aPR) and 95% confidence intervals (CI).ResultsAmong 1767 participants, 704 (39.8%) self-reported receiving HPV vaccine. Median age at vaccination (18.7 years) was older than age at first sex (15.7 years). Quadrivalent vaccine-type HPV was detected in anal or oral specimens from 475 (26.9%) participants. Vaccine-type HPV prevalence was lower among vaccinated (22.9%) compared with unvaccinated (31.6%) participants; aPR for those who initiated vaccination at age ≤18 years was 0.41 (CI, 0.24-0.57) and at age >18 years was 0.82 (CI, 0.67-0.98). Vaccine effectiveness of at least 1 HPV vaccine dose at age ≤18 years or >18 years was 59% and 18%, respectively.ConclusionsFindings suggest real-world effectiveness of HPV vaccination among young adult MSM. This effect was stronger with younger age at vaccination

Removal of the Textile Dye Indanthrene Olive Green from Aqueous Solution Using Chitosan

The kinetics and equilibrium of the adsorption of Indanthrene Olive Green (IOG) from aqueous solution onto chitosan have been investigated. The chitosan was characterised in terms of its average degree of de-acetylation (DD) and by XRD, TGA/DTG, IR, SEM and specific BET surface area methods. Batch adsorptions experiments were carried out at different pH values and dye concentrations. It was found that the adsorption process was favoured by acidic pH conditions (4.0–6.0). The adsorption followed second-order rate kinetics and the experimental equilibrium data followed the Langmuir isotherm, thereby suggesting that chemisorption might be the major adsorption mode. Such adsorption also occurred on chitosan fibres, although to a significantly lower extent than on crushed chitosan. The corresponding thermodynamic parameters (ΔG 0 , ΔH 0 and ΔS 0 ) were calculated. The positive values obtained for ΔH 0 (161.7 kJ/mol) and ΔS 0 [559.9 J/(mol K)] suggest that the adsorption process was endothermic, with the randomness of the system increasing during the adsorption process. A simplified adsorption model has also been proposed