Molecular Cloning, Expression Analysis, and Functional Analysis of Nine IbSWEETs in Ipomoea batatas (L.) Lam.

Sugar Will Eventually be Exported Transporter (SWEET) genes play an important regulatory role in plants' growth and development, stress response, and sugar metabolism, but there are few reports on the role of SWEET proteins in sweet potato. In this study, nine IbSWEET genes were obtained via PCR amplification from the cDNA of sweet potato. Phylogenetic analysis showed that nine IbSWEETs separately belong to four clades (Clade I~IV) and contain two MtN3/saliva domains or PQ-loop superfamily and six~seven transmembrane domains. Protein interaction prediction showed that seven SWEETs interact with other proteins, and SWEETs interact with each other (SWEET1 and SWEET12; SWEET2 and SWEET17) to form heterodimers. qRT-PCR analysis showed that IbSWEETs were tissue-specific, and IbSWEET1b was highly expressed during root growth and development. In addition to high expression in leaves, IbSWEET15 was also highly expressed during root expansion, and IbSWEET7, 10a, 10b, and 12 showed higher expression in the leaves. The expression of SWEETs showed a significant positive/negative correlation with the content of soluble sugar and starch in storage roots. Under abiotic stress treatment, IbSWEET7 showed a strong response to PEG treatment, while IbSWEET10a, 10b, and 12 responded significantly to 4 °C treatment and, also, at 1 h after ABA, to NaCl treatment. A yeast mutant complementation assay showed that IbSWEET7 had fructose, mannose, and glucose transport activity; IbSWEET15 had glucose transport activity and weaker sucrose transport activity; and all nine IbSWEETs could transport 2-deoxyglucose. These results provide a basis for further elucidating the functions of SWEET genes and promoting molecular breeding in sweet potato.

Prevalence of syphilis and risk factors among HIV-positive men who have sex with men in Guangdong province.

Background: HIV-positive men who have sex with men (MSM) tend to have high syphilis incidence. Our objective is to evaluate the prevalence of syphilis and determine the risk factors of syphilis among HIV-positive MSM. Methods: A cross-sectional study with convenience sampling was performed among HIV-positive MSM in six cities of Guangdong Province from June 2020 to August 2021. Participants completed a survey including social-demographic characteristics, sexual behaviors and self-reported syphilis, chlamydia, gonorrhea, herpes, human papillomavirus statuses after HIV diagnosis. Multivariate logistic regression was used to determine the factors associated with syphilis and sexually transmitted diseases (STD). Results: Among 944 HIV-positive MSM, 141 (14.9, 95% CI: 12.7-17.2%) men had syphilis and 220 (23.3, 95% CI: 20.6-26.0%) men had STD. Multivariate analysis indicated that MSM who met male sexual partners mainly through traditional meeting places (spa or bath house, sauna, foot or body massage parlor) in the last 6 months [adjusted Odds Ratio (aOR) = 2.91, 95% CI: 1.09-7.79], and who were diagnosed with herps after the HIV diagnosis (aOR = 3.79, 95% CI: 1.16-12.39) were more likely to have syphilis. In addition, MSM who met male sexual partners mainly through traditional meeting places in the last 6 month (aOR = 2.55, 95% CI: 1.01-6.42), and who had more than one male sexual partner in the last 6 months (aOR = 1.88, 95% CI: 1.17-3.02) were more likely to have STD. Conclusions: The prevalence of syphilis and other STDs is relatively high among HIV-positive MSM in southern China. Routine syphilis screening as a part of HIV monitoring among HIV-positive MSM will have important epidemiological significance for the management of infected patients, and can help reduce the spread of syphilis.

Trends in HIV Prevalence and HIV-Related Risk Behaviors Among Male Students Who Have Sex With Men From 2016 to 2020 in Nanjing, China: Consecutive Cross-Sectional Surveys.

Background: The growing HIV epidemic among student men who have sex with men (MSM) necessitates immediate attention from public health. In China, male students who have sex with men (SMSM) were also at an increasing risk of HIV transmission. The aim of this study was to investigate the trends in HIV prevalence, HIV-related risk behaviors, and HIV testing, as well as analyze the factors associated with HIV infection among SMSM in Nanjing. Methods: Data were collected through face-to-face questionnaire interviews and laboratory testing in Nanjing. The participants were recruited among SMSM by snowball sampling and internet-recruited convenience sampling annually from 2016 to 2020. The self-report data primarily included demographics, HIV knowledge, HIV-related behaviors, and HIV testing, while the laboratory test results of HIV and syphilis were collected. Linear-by-linear chi-square test was used to analyze the trends of HIV/syphilis prevalence and its risk behaviors. The binary logistic regression model was used to explore the factors associated with HIV infection. Results: During the 5 years from 2016 to 2020, a total of 775 SMSM were recruited in our survey (220, 112, 171, 142, and 120, respectively). The HIV prevalence was 5.2, 6.3, 5.3, 7.0, and 8.3%, without a significant increasing trend (P = 0.277). Syphilis prevalence fluctuated from 5.7% in 2016 to 4.2% in 2020, without a significant decreasing trend (P = 0.318). The proportion of consistent condom use in anal intercourse (48.5 to 56.2%, P < 0.05), and HIV testing in the past 12 months (51.0 to 59.2%, P < 0.05) were increasing. A remarkable growing trend has been reported in the percentage of MSM with more than one male sex partner (46.2 to 59.2%, P < 0.05). Multivariate analysis showed that HIV testing in the past 12 months was a protective factor against HIV infection. MSM who had unprotected anal intercourse (UAI) in the past 6 months, recreational drug use, and currently syphilis infection were risk factors for HIV infection. Conclusions: We observed stable HIV/ syphilis prevalence, increasing consistent condom use, increasing HIV testing rate, and increasing multiple male sex partners dramatically among SMSM in China. The original comprehensive intervention measures should be continuously strengthened for the subgroup. To satisfy the current HIV prevention requirements, new biological interventions should be introduced and carried out as major components of combination prevention programs.