RESUMO
Objective To investigate the effect of smoking on the semen quality in infertile men.Methods A total of 360 male infertility patients were enrolled and divided into the smoking group(n=190)and non-smoking group(n=170)based on whether they smoked or not.Furthermore,the smoking group was subdivided into group A(≤10 sticks/d,n=63),group B(11～20 sticks/d,n=80),and group C(>20 sticks/d group,n=47)according to the amount of smoking.Semen volume,liquefaction time,sperm concentration,motility,DNA fragmentation rate and normal morphological rate were observed and compared between and within the groups.Results There were significant differences in semen volume,liquefaction time,sperm motility,normal morphological rate and DNA fragmentation rate between the smoking group and the non-smoking group(P<0.05).The semen volume,sperm motility and normal morphological rate of the smoking group were lower than those in the non-smoking group,and the DNA fragmentation rate and semen liquefaction time were higher than those in the non-smoking group.And with the increase of smoking volume,sperm motility and normal morphological rate decreased,semen liquefaction time and DNA fragmentation rate increased,and there was no significant difference in the sperm concentration between the smoking group and non-smoking group(P>0.05).There was no significant difference in the semen volume between the three groups with different smoking amounts(P>0.05).Conclusion Smoking has a negative impact on the sperm quality parameters such as semen volume,sperm motility,normal morphological rate,sperm motility,liquefaction time and DNA fragmentation,and the effect of heavy smoking is particularly obvious.We should strengthen the comprehensive health education,promote the healthy lifestyles and reduce smoking.
RESUMO
Heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria are aerobic microorganisms that can remove nitrogen under high-salt conditions, but their performance in practical applications are not satisfactory. As a compatible solute, trehalose helps microorganisms to cope with high salt stress by participating in the regulation of cellular osmotic pressure, and plays an important role in promoting the nitrogen removal efficiency of microbial populations in the high-salt environment. We investigated the mechanism of exogenous-trehalose-enhanced metabolism of HN-AD community under high-salt stress by starting up a membrane aerobic biofilm reactor (MABR) to enrich HN-AD bacteria, and designed a C150 experimental group with 150 μmol/L trehalose addition and a C0 control group without trehalose. The reactor performance and the community structure showed that NH4+-N, total nitrogen (TN) and chemical oxygen demand (COD) removal efficiency were increased by 29.7%, 28.0% and 29.1%, respectively. The total relative abundance of salt-tolerant HN-AD bacteria (with Acinetobacter and Pseudofulvimonas as the dominant genus) in the C150 group reached 66.8%, an 18.2% increase compared with that of the C0 group. This demonstrated that trehalose addition promoted the enrichment of salt-tolerant HN-AD bacteria in the high-salt environment to enhance the nitrogen removal performance of the system. In-depth metabolomics analysis showed that the exogenous trehalose was utilized by microorganisms to improve proline synthesis to increase resistance to high-salt stress. By regulating the activity of cell proliferation signaling pathways (cGMP-PKG, PI3K-Akt), phospholipid metabolism pathway and aminoacyl-tRNA synthesis pathway, the abundances of phosphoethanolamine, which was one of the glycerophospholipid metabolites, and purine and pyrimidine were up-regulated to stimulate bacterial aggregation and cell proliferation to promote the growth of HN-AD bacteria in the high-salt environment. Meanwhile, the addition of trehalose accelerated the tricarboxylic acid (TCA) cycle, which might provide more electron donors and energy to the carbon and nitrogen metabolisms of HN-AD bacteria and promote the nitrogen removal performance of the system. These results may facilitate using HN-AD bacteria in the treatment of high-salt and high-nitrogen wastewater.