Expression and Characterization of the Flocculin Flo11/Muc1, a Yeast Mannoprotein with Homotypic Properties of Adhesion

The Flo11/Muc1 flocculin has diverse phenotypic effects. Saccharomyces cerevisiae cells of strain background Σ1278b require Flo11p to form pseudohyphae, invade agar, adhere to plastic, and develop biofilms, but they do not flocculate. We show that S. cerevisiae var. diastaticusstrains, on the other hand, exhibit Flo11-dependent flocculation and biofilm formation but do not invade agar or form pseudohyphae. In order to study the nature of the Flo11p proteins produced by these two types of strains, we examined secreted Flo11p, encoded by a plasmid-borne gene, in which the glycosylphosphatidylinositol anchor sequences had been replaced by a histidine tag. A protein of approximately 196 kDa was secreted from both strains, which upon purification and concentration, aggregated into a form with a very high molecular mass. When secreted Flo11p was covalently attached to microscopic beads, it conferred the ability to specifically bind to S. cerevisiae var. diastaticus cells, which flocculate, but not to Σ1278b cells, which do not flocculate. This was true for the 196-kDa form as well as the high-molecular-weight form of Flo11p, regardless of the strain source. The coated beads bound to S. cerevisiae var. diastaticus cells expressing FLO11 and failed to bind to cells with a deletion of FLO11, demonstrating a homotypic adhesive mechanism. Flo11p was shown to be a mannoprotein. Bead-to-cell adhesion was inhibited by mannose, which also inhibits Flo11-dependent flocculation in vivo, further suggesting that this in vitro system is a useful model for the study of fungal adhesion. The fungal adhesins are a family of cell surface proteins that mediate adherence to environmental substrates or to other cells (7, 45). Adhesins are critically important in the initial steps of fungal pathogenicity, when fungal cells must adhere to host tissue. For the common human pathogens Candida albicans and Candida glabrata, the involvement of multiple adhesins in the adherence of fungal cells to host tissue has been demonstrated (4, 5, 18, 26, 43). Among the adhesins is the flocculin family of Saccharomyces cerevisiae cell wall proteins that mediate flocculation, which is asexual calcium-dependent cell-cell aggregation. The most recently described member of the yeast flocculin gene family, FLO11/MUC1 (24, 30), is the only flocculin expressed in the Σ1278b strain of S. cerevisiae (17), and it exhibits a wide variety of phenotypes. Some of these phenotypes are strain specific. Yeast cells of strain background Σ1278b have been shown to require FLO11 for invasive growth (23, 30), the development of pseudohyphae (24, 29), and the formation of biofilms on plastic (36), but they do not flocculate. On the other hand, the variant strain S. cerevisiae var. diastaticus, which is highly flocculent, has been shown to require FLO11 for flocculation (30). FLO11 is also required in Σ1278b strains for the formation of mats with hub and spoke structures on semisolid agar (36). The common laboratory strain background S288C does not express FLO11 due to a nonsense mutation in the transcriptional activator FLO8(28). In some industrial strains, FLO11 mediates formation of the specialized biofilms called flors that are necessary for the production of sherry wine (19, 48). The common feature of all these phenotypes is adhesion. Commensurate with the many different pathways that regulate its expression, FLO11 has been shown to have a promoter that is among the largest described for yeast, at over 3 kb (38). Much more is known about gene regulation of FLO11 (for reviews, see references 11, 25, and 32) than about the structure and function of the protein. We further investigated the FLO11-dependent phenotypes of S. cerevisiae var. diastaticus and found that it also differs from Σ1278b in that the haploids do not invade agar and the diploids do not form pseudohyphae. In order to investigate these strain differences in the phenotypes of FLO11we expressed and purified the Flo11 proteins from S. cerevisiae var. diastaticus and from Σ1278b and examined their properties. An in vitro system was created for studying the adhesive characteristics of the expressed Flo11 by attaching the protein to microscopic beads and testing the adhesive properties of the beads. Microscopic beads that can be coated covalently with proteins or ligands have been used to simplify several complex biological processes. For example, Gaur and Klotz used microscopic magnetic beads coated with extracellular matrix proteins to isolate a C. albicans adhesin gene, ALS5, by expression cloning in S. cerevisiae (13). Further work using such beads resulted in characterization of the adhesion properties of Ala1p and Als1p (12, 14, 15, 21, 22, 35). In this study, we have used this approach to study the in vitro properties of purified Flo11 proteins from two different strains

Differential Relationships of Stress and HIV Disclosure by Gender: A Person Centered Longitudinal Study

Background: Existing literature mostly consider HIV disclosure as a static event and investigate its relationship with stress using a cross-sectional design. It is unclear about the dynamic changes of HIV disclosure levels (defined as the number of disclosure targets) and how stress may influence these changes. This study explored different disclosure levels using a person-centered longitudinal approach, examined whether stress could predict these disclosure levels, and investigated if this relationship differed by gender among people living with HIV (PLWH). Methods: Data were derived from a prospective cohort study conducted from November 2016 to January 2018 in Guangxi, China. Four hundred forty-four PLWH were included. Participants were assessed on perceived stress, sociodemographic characteristics, and number of HIV disclosure targets at baseline, 6-month, and 12-month followups. Growth mixture modeling was used to characterize disclosure levels based on the changes of disclosure target number. Multinomial logistic regression was used to predict disclosure levels with baseline stress after adjusting for covariates. The interaction effect of stress by gender was examined. Adjusted odds ratio (AOR) with its 95% confidence interval were reported to show the strength of association. Results: Three levels of disclosure were characterized as “Low levels of disclosure” (Level One), “Increased levels of disclosure” (Level Two), and “High levels of disclosure” (Level Three). Accordingly, 355 (81.2%), 28 (6.4%), and 64 (12.4%) of PLWH were categorized respectively under low, increased, and high levels of disclosure. The interaction of baseline stress by gender was significant in differentiating Level One from Three (AOR = 0.85 [0.74 ~ 0.99]) while it was not significant between Level One and Two (AOR = 0.96 [0.81 ~ 1.15]). Compared to female, male PLWH with higher baseline stress had lower probability to have consistent high disclosure levels over time. PLWH who were married/cohabited had lower probability of being classified into consistent high levels of disclosure than low level (AOR = 0.43 [0.19 ~ 0.94]). Conclusions: There was gender difference in the relationship between stress and levels of HIV disclosure. To promote HIV disclosure, gender tailored interventions should be employed to help PLWH cope with stress

Examining Social Determinants of Health During a Pandemic: Clinical Application of Z Codes Before and During COVID-19

Recognition of the impact of social determinants of health (SDoH) on healthcare outcomes, healthcare service utilization, and population health has prompted a global shift in focus to patient social needs and lived experiences in assessment and treatment. The International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) provides a list of non-billable “Z codes” specific to SDoH for use in electronic health records. Using population-level analysis, this study aims to examine clinical application of Z codes in South Carolina before and during the COVID-19 pandemic. The study population consists of South Carolina residents who had a healthcare visit and had their COVID-19 test result reported to the state\u27s Department of Health and Environmental Control before January 14, 2021. Of the 1,190,531 individuals in the overall sample, Z codes were used only for 14,665 (1.23%) of the patients, including 2,536 (0.97%) COVID-positive patients and 12,129 (1.30%) COVID-negative patients. Compared with hospitals that did not use Z codes, those that did were significantly more likely to have higher bed capacity (p = 0.017) and to be teaching hospitals (p = 0.03), although this was significant only among COVID-19 positive individuals. Those at inpatient visits were most likely to receive Z codes (OR: 5.26; 95% CI: 5.14, 5.38; p \u3c 0.0001) compared to those at outpatient visits (OR: 0.07; 95%CI: 0.06, 0.07; p \u3c 0.0001). There was a slight increase of Z code use from 2019 to 2020 (OR: 1.33, 95% CI: 1.30, 1.36; p \u3c 0.0001), which was still significant when stratified by facility type across time. As one of the first studies to examine Z code use among a large patient population, findings clearly indicate underutilization by providers. Additional study is needed to understand the potentially long-lasting health effects related to SDoH among underserved populations

Urinary estrogen metabolites and prostate cancer : a case-control study and meta-analysis

Objective: To investigate prostate cancer (Pca) risk in relation to estrogen metabolism, expressed as urinary 2-hydroxyestrone (2-OHE1), 16α-hydroxyestrone (16α-OHE1) and 2-OHE1 to 16α-OHE1 ratio. Methods: We conducted a case-control study within the Western New York Health Cohort Study (WNYHCS) from 1996 to 2001. From January 2003 through September 2004, we completed the re-call and follow-up of 1092 cohort participants. Cases (n = 26) and controls (n = 110) were matched on age, race and recruitment period according to a 1:4 ratio. We used the unconditional logistic regression to compute crude and adjusted odds ratios (OR) and 95% confident interval (CI) of Pca in relation to 2-OHE1, 16αOHE1 and 2-OHE1 to 16α-OHE1 by tertiles of urine concentrations (stored in a biorepository for an average of 4 years). We identified age, race, education and body mass index as covariates. We also conducted a systematic review of the literature which revealed no additional studies, but we pooled the results from this study with those from a previously conducted case-control study using the DerSimonian-Laird random effects method. Results: We observed a non-significant risk reduction in the highest tertile of 2-OHE1 (OR 0.72, 95% CI 0.25-2.10). Conversely, the odds in the highest tertile of 16α-OHE1 showed a non-significant risk increase (OR 1.76 95% CI 0.62-4.98). There was a suggestion of reduced Pca risk for men in the highest tertile of 2-OHE1 to 16α-OHE1 ratio (OR 0.56, 95% CI 0.19-1.68). The pooled estimates confirmed the association between an increased Pca risk and higher urinary levels of 16α-OHE1 (third vs. first tertile: OR 1.82, 95% CI 1.09-3.05) and the protective effect of a higher 2-OHE 1 to 16α-OHE1 ratio (third vs. first tertile: OR 0.53, 95% CI 0.31-0.90). Conclusion: Our study and the pooled results provide evidence for a differential role of the estrogen hydroxylation pathway in Pca development and encourage further study

HIV-Related Stigma, Sexual Identity, and Depressive Symptoms Among MSM Living With HIV: A Moderated Mediation Modeling Analysis

Depression is one of the biggest health issues among men who have sex with men (MSM) living with HIV, where sexual identity might play an intricate role. Yet, findings of the relationship between sexual identity and depression were mixed and few studies explored its underlying mechanisms. This study aimed to examine the association between sexual identity and depression, and the potential mediating role of HIV-related stigma and moderating role of age. A cross-sectional survey was conducted among 203 MSM living with HIV in Guangxi, China. Participants provided information on sexual identity, depression, HIV-related stigma, and background information. Descriptive statistics, bivariate analysis, and path analysis were applied to examine our hypotheses. Bivariate analysis demonstrated that participants who self-identified as gay reported a lower level of HIV-related stigma and depression. Path analysis revealed an insignificant direct effect of identifying as gay on depression. Yet, the indirect pathway was significant, with identifying as gay being associated with a lower level of HIV stigma and thus a lower level of depression. This indirect effect was moderated by age. The conditional indirect effect was significant in the younger group yet ceased in the older group. The study provided information to better understand the effect of sexual identity on mental health among stigmatized sexual and gender minorities by highlighting the mediating effect of HIV-related stigma and the protective effect of age. Interventions targeting mental health of MSM living with HIV might consider placing greater emphasis on addressing HIV-related stigma among younger MSM

The Role of Mental Health on the Relationship Between Food Insecurity and Immunologic Outcome Among People Living With HIV in Guangxi, China

BACKGROUND Previous studies showed that food insecurity could adversely affect clinical outcomes of people living with HIV (PLWH). The mental health pathways of such effects are suggested in existing literature, but empirical data are limited in resource-limited settings. METHODS This cross-sectional study aims to explore the role of depressive symptoms and anxiety on the association between food insecurity and CD4 counts among a sample of 2,987 PLWH in Guangxi, China. Path analysis was used to examine a hypothetical model and delta ztest was used to assess the indirect effects of food insecurity on CD4 counts through depressive symptoms and anxiety. RESULTS The prevalence of food insecurity in this sample was 25.3%, and the median CD4 counts were 318 cells/mm3. In correlation analyses, food insecurity was not directly associated with LogCD4 but was associated with depressive symptoms and anxiety. Path analysis indicated a significant indirect effect from food insecurity to LogCD4 through depressive symptoms, but not anxiety. CONCLUSION Improving mental health among PLWH with food insecurity may be beneficial for treatment outcomes. Besides intervening food insecurity, an intervention targeting depressive symptoms could improve the immunologic outcomes of PLWH

The Extent of Distraction of Cell Phone Conversations for Passengers in Simulated Flight

Currently, passengers are forbidden from making cell phone calls during flights in the United States due to safety concerns. However, some related research has demonstrated that the interference of cell phone use with avionics and ground network is minimal or can be eliminated by using modern technology. Although conversing on the cell phone does not cause electronic interference, the distraction of a passenger caused by a cell phone may negatively impact safety. The cell phone calls have been found to affect people’s attention and performance. In-flight announcements are popular methods to inform commercial airliner passengers of their situation and aircraft’s status. If a passenger’s attention is distracted from the announcements by the phone call, it would inhibit the passenger from being aware of important information. The purpose of this study was to compare the extent of safety compliance (checking seatbelts, raising tray tables) and retention of announcements among three groups: cell phone conversation, face-to-face conversation (i.e., talking with the passenger next to them), and control. Findings revealed that the cell phone group and the face-to-face group recalled less information from safety announcement and complied with safety behaviors to a lesser degree than the control group. The face-to-face group was not safer than the cell phone group on any measure. Lifting the cell phone ban should be considered. Additional research in regard to safety implications of passengers engaged in conversation warrants further study

LC-MS/MS Quantification of Nevirapine and Its Metabolites in Hair for Assessing Long-Term Adherence

The adherence assessment based on the combination of nevirapine (NVP) and its two metabolites (2-hydroxynevirapine and 3-hydroxynevirapine) would more comprehensively and accurately reflect long-term adherence than that of a single prototype. This study aimed to develop a specific, sensitive and selective method for simultaneous detection of the three compounds in hair and explore whether there was consistency among the three compounds in assessing long-term adherence. Furthermore, 75 HIV-positive patients who were taking the NVP drug were randomly recruited and divided into two groups (high-and low-adherence group). All participants self-reported their days of oral drug administration per month and provided their hair strands closest to the scalp at the region of posterior vertex. The concentrations of three compounds in the hair were determined using a developed LC-MS/MS method in multiple reaction monitoring. This method showed good performances in limit of quantification and accuracy with the recoveries from 85 to 115% and in precision with the intra-day and inter-day coefficients of variation within 15% for the three compounds. The population analysis revealed that patients with high-adherence showed significantly higher concentrations than those with low-adherence for all three compounds. There were significantly moderate correlations of nevirapine with 2-hydroxynevirapine and 3-hydroxynevirapin and high correlation between 2-hydroxynevirapine and 3-hydroxynevirapin. The two NVP’s metabolites showed high consistency with NVP in evaluating long-term adherence