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Background: Potential adverse effects of non-optimum temperatures on human semen quality have drawn much concern worldwide; however, the exposure–response relationship remains less understood. Objectives: To quantitatively assess the association between exposure to ambient temperature and semen quality in South China, and to identify potential critical exposure windows. Methods: We conducted a longitudinal study to investigate 11,050 volunteers who lived in Guangdong province, China and intended to donate sperm in the Guangdong provincial human sperm bank during 2016–2021. Exposure to ambient temperature during 0–90 days before semen collection was assessed by extracting daily temperatures from a validated grid dataset at each subject’s residential address. Linear mixed models and linear regression models were used to perform exposure–response analyses. Results: During the study period, the 11,050 subjects underwent 44,564 semen analyses. Each 5 °C increase of lag 0–90 day exposure to ambient temperature was approximately linearly associated with a 3.11 (95 % confidence interval [CI]: 2.08, 4.14) × 106/ml, 9.31 (4.83, 13.80) × 106, 1.27 % (0.91 %, 1.62 %), 8.20 (5.33, 11.08) × 106, 1.37 % (1.01 %, 1.74 %), 8.29 (5.52, 11.06) × 106, 0.67 % (0.28 %, 1.05 %), and 4.50 (2.20, 6.80) × 106 reduction in sperm concentration, total sperm number, total motility, total motile sperm number, progressive motility, total progressive sperm number, normal forms, and total normal form sperm number, respectively (all p 0.05). We identified a critical exposure period of 10–14 days before semen collection for sperm motility, and 70–90 days before semen collection for sperm count and morphology. Conclusions: Our study provides consistent evidence that higher ambient temperature was significantly associated with a reduction in semen quality in South China. The findings highlight the needs to reduce high temperature exposures during 3 months before ejaculation to maintain better semen quality.

Background: Chronic obstructive pulmonary disease (COPD) hospitalization has been linked with ambient air pollution. However, the evidence on respiratory health benefits from air pollution control policy in China is limited. Objective: To investigate benefits from the Three-Year Action Plan to Win the Battle for a Blue Sky (TYAP) for tackling COPD hospitalization due to ambient air pollution. Methods: We conducted a time-stratified case-crossover study of 138,015 COPD hospitalizations aged ≥ 60 years in Guangdong province, China during 2016–2019 to investigate respiratory health benefits from TYAP. Inverse distance weighting method was used to assess daily individual-level exposures to ambient air pollutants including particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM2.5), particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3). Conditional logistic regression model was applied to analyze the associations between ambient air pollutants and COPD hospitalization. Results: TYAP can modify the associations. Each 10 μg/m3 increase of exposure to PM2.5, PM10, and NO2 and 1 mg/m3 increase of exposure to CO were significantly associated with 2.5%, 2.0%, 3.0%, and 14.4% increase in odds of COPD hospitalization before TYAP, respectively; while 1.0%, 0.9%, 1.5%, and 5.8% increase in odds during TYAP. We found prominent declines in health burden of COPD hospitalizations due to air pollution among the elderly after TYAP implication when compared with that before TYAP. Conclusion: Reduced levels of ambient air pollutants by TYAP can effectively lower the risk for COPD hospitalization among the elderly, which provides evidence on the respiratory health benefits from consistent and effective air pollution control policy.

Background: Exposure to residential greenness has been associated with benefits on certain reproductive health outcomes. However, its potential benefits on semen quality remain unknown. Objectives: To quantitatively explore the association between exposure to residential greenness and semen quality. Methods: We investigated 9142 sperm donation volunteers who underwent 38,682 semen examinations at Guangdong provincial human sperm bank in China during 2016–2019. Exposure to residential greenness was assessed using mean daily Normalized Difference Vegetation Index (NDVI) at each subject’s residential address with a 400 m buffer during 0–90 days before each semen collection. Multivariate linear mixed models and linear regression models were used to assess the association between exposure to residential greenness and semen quality. Results: An interquartile range increase in exposure to residential greenness was significantly associated with a 0.034 (95% confidence interval [CI]: 0.005, 0.063) ml, 4.06 (95% CI: 0.76, 7.37) × 106, and 0.32% (95% CI: 0.22%, 0.41%) increase in semen volume, total sperm number, and normal forms, respectively; similar trends were observed across quartiles of exposure to residential greenness (all p-values for liner trend

The apextrin C-terminal (ApeC) domain is a class of newly discovered protein domains with an origin dating back to prokaryotes. ApeC-containing proteins (ACPs) have been found in various marine and aquatic invertebrates, but their functions and the underlying mechanisms are largely unknown. Early studies suggested that amphioxus ACP1 and ACP2 bind to bacterial cell walls and have a role in immunity. Here we identified another two amphioxus ACPs (ACP3 and ACP5), which belong to the same phylogenetic clade with ACP1/2, but show distinct expression patterns and sequence divergence (40-50% sequence identities). Both ACP3 and ACP5 were mainly expressed in the intestine and hepatic cecum, and could be up-regulated after bacterial challenge. Both prokaryotic-expressed recombinant ACP3 and ACP5 could bind with several species of bacteria and yeasts, showing agglutinating activity but no microbicidal activity. ELISA assays suggested that their ApeC domains could interact with peptidoglycan (PGN), but not with lipoteichoic acid (LTA), lipopolysaccharides (LPS) and zymosan A. Furthermore, they can only bind to Lys-type PGN from Staphylococcus aureus, but not to DAP-type PGN from Bacillus subtilis and not to moieties of PGN such as MDPs, NAMs and NAGs. This recognition spectrum is different from that of ACP1/2. We also found that when expressed in mammalian cells, ACP3 could interact with TRAF6 via a conserved non-ApeC region, which inhibited the ubiquitination of TRAF6 and hence suppressed downstream NF-κB activation. This work helped define a novel subfamily of ACPs, which have conserved structures, and have related yet diversified molecular functions. Its members have dual roles, with ApeC as a lectin and a conserved unknown region as a signal transduction regulator. These findings expand our understanding of the ACP functions and may guide future research on the role of ACPs in different animal clades.