Unveiling the inhibitory mechanisms of chromium exposure on microbial reductive dechlorination: Kinetics and microbial responses.

Chromium and organochlorine solvents, particularly trichloroethene (TCE), are pervasive co-existing contaminants in subsurface aquifers due to their extensive industrial use and improper disposal practices. In this study, we investigated the microbial dechlorination kinetics under different TCE-Cr(Ⅲ/VI) composite pollution conditions and elucidated microbial response mechanisms based on community shift patterns and metagenomic analysis. Our results revealed that the reductive dechlorinating consortium had high resistance to Cr(III) but extreme sensitivity to Cr(VI) disturbance, resulting in a persistent inhibitory effect on subsequent dechlorination. Interestingly, the vinyl chloride-respiring organohalide-respiring bacteria (OHRB) was notably more susceptible to Cr(III/VI) exposure than the trichloroethene-respiring one, possibly due to inferior competition for growth substrates, such as electron donors. In terms of synergistic non-OHRB populations, Cr(III/VI) exposure had limited impacts on lactate fermentation but significantly interfered with H2-producing acetogenesis, leading to inhibited microbial dechlorination due to electron donor deficiencies. However, this inhibition can be effectively mitigated by the amendment of exogenous H2 supply. Furthermore, being the predominant OHRB, Dehalococcoides have inherent Cr(VI) resistance defects and collaborate with synergistic non-OHRB populations to achieve concurrent bio-detoxication of Cr(VI) and TCE. Our findings expand the understanding of the response patterns of different functional populations towards Cr(III/VI) stress, and provide valuable insights for the development of in situ bioremediation strategies for sites co-contaminated with chloroethene and chromium.

The effects of arsenic on dechlorination of trichloroethene by consortium DH: Microbial response and resistance.

Inorganic arsenic and organochlorines are frequently co-occurring contaminants in anoxic groundwater environments, and the bioremediation of their composite pollution has long been a rigorous predicament. Currently, the dechlorination behaviors and stress responses of microbial dechlorination consortia to arsenic are not yet fully understood. This study assessed the reductive dechlorination performance of a Dehalococcoides-bearing microcosm DH under gradient concentrations of arsenate [As(V)] or arsenite [As(III)] and investigated the response patterns of different functional microorganisms. Our results demonstrated that although the dechlorination rates declined with increasing arsenic concentrations in both As(III/V) scenarios, the inhibitory impact was more pronounced in As(III)-amended groups compared to As(V)-amended groups. Moreover, the vinyl chloride (VC)-to-ethene step was more susceptible to arsenic exposure compared to the trichloroethene (TCE)-to-dichloroethane (DCE) step, while high levels of arsenic exposure [e.g. As(III) > 75 µM] can induce significant accumulation of VC. Functional gene variations and microbial community analyses revealed that As(III/V) affected reductive dechlorination by directly inhibiting organohalide-respiring bacteria (OHRB) and indirectly inhibiting synergistic populations such as acetogens. Metagenomic results indicated that arsenic metabolic and efflux mechanisms were identical among different Dhc strains, and variations in arsenic uptake pathways were possibly responsible for their differential responses to arsenic exposures. By comparison, fermentative bacteria showed high potential for arsenic resistance due to their inherent advantages in arsenic detoxification and efflux mechanisms. Collectively, our findings expanded the understanding of the response patterns of different functional populations to arsenic stress in the dechlorinating consortium and provided insights into modifying bioremediation strategies at co-contaminated sites for furtherance.

Bioelectrochemical system accelerates reductive dechlorination through extracellular electron transfer networks.

Bioelectrochemical system is considered as a promising approach for enhanced bio-dechlorination. However, the mechanism of extracellular electron transfer in the dechlorinating consortium is still a controversial issue. In this study, bioelectrochemical systems were established with cathode potential settings at -0.30 V (vs. SHE) for trichloroethylene reduction. The average dechlorination rate (102.0 µM Cl·d-1) of biocathode was 1.36 times higher than that of open circuit (74.7 µM Cl·d-1). Electrochemical characterization via cyclic voltammetry illustrated that electrostimulation promoted electrochemical activity for redox reactions. Moreover, bacterial community structure analyses indicated electrical stimulation facilitated the enrichment of electroactive and dechlorinating populations on cathode. Metagenomic and quantitative polymerase chain reaction (qPCR) analyses revealed that direct electron transfer (via electrically conductive pili, multi-heme c-type cytochromes) between Axonexus and Desulfovibrio/cathode and indirect electron transfer (via riboflavin) for Dehalococcoides enhanced dechlorination process in BES. Overall, this study verifies the effectiveness of electrostimulated bio-dechlorination and provides novel insights into the mechanisms of dechlorination process enhancement in bioelectrochemical systems through electron transfer networks.

Developmental synergism in the management of oral potentially malignant disorders.

Oral potentially malignant disorders (OPMDs) are associated with an increased risk of occurrence of cancers of the oral cavity or lips. The unifying theme of OPMDs is their potential risk for cancer development. Therefore, the primary objective of the management should be to prevent carcinogenesis. Beyond diagnosis, current strategies for the management of OPMDs predominantly include non-surgical and surgical interventions and a "watch-and-see" approach, such as disease monitoring or surveillance, and preventive strategies. Though no optimal clinical treatment has gained universal approval for reducing or preventing malignant development of OPMDs. Therefore, an urgent need exits for improved treatment properties and effective predictive markers for OPMDs treatment. This review aims to outline recent synergism regarding to the management of OPMDs. Developing new technologies and improved application parameters to promote the treatment efficacy and a novel management prescription approach to OPMDs are proposed.

[Semen expulsion under the ureterocystoscope].

OBJECTIVE: To determine the exact location of the opening of the ejaculatory duct in men and provide some basic anatomical evidence for seminal vesiculoscopy and the treatment of ejaculatory duct obstruction. METHODS: We performed ureterocystoscopy for 21 male patients aged 26 - 47 years with hematuria (n = 12), hematospermia (n = 2), glandular cystitis (n = 6), and anejaculation after radical resection of rectal carcinoma (n = 1), and meanwhile, with the consent of the patients, massaged the prostate and ejaculatory duct and observed the outlet of the expelled fluid. Under the microscope, we described the fluid samples with sperm as the expulsion from the ejaculatory duct. RESULTS: Ureterocystoscopy showed that the exact anatomical sites of the expulsion of prostatic fluid and semen in the patients were the side and lower side of the prostatic utricle opening above the verumontanum and the ventral side of the verumontanum. Quantities of sperm were found in the expulsion fluid of 13 of the patients, and no expulsion, including semen, was seen from the prostatic utricle opening. CONCLUSION: Anatomically, the ejaculatory duct openings of males are located at the two sides of the verumontanum adjacent to the opening of the prostatic utricle, rather than in the prostatic utricle above the verumontanum.

[Outcomes of IVF-ET and percentage of morphologically normal sperm before and after swim-up treatment].

OBJECTIVE: To study the relationship between sperm morphology and the outcomes of in vitro fertilization-embryo transfer (IVF-ET) before and after swim-up treatment of sperm on the day of oocyte retrieval. METHODS: This study included 94 couples to be treated by IVF-ET for tubal factor infertility. Sperm samples were collected on the day of oocyte retrieval and sperm morphology evaluated according to the Kruger criteria before and after swim-up treatment. Based on the results of morphological evaluation, the sperm samples were divided into groups A1 (morphologically normal sperm > or = 10% after swim-up treatment), A2 (morphologically normal sperm < 10% after swim-up treatment), B1 (morphologically normal sperm > or = 10% before swim-up treatment) and B2 (morphologically normal sperm < 10% before swim-up treatment). The outcomes of IVF-ET treatment were compared between groups A1 and A2 as well as between B1 and B2. RESULTS: After swim-up treatment, the rates of fertilization, cleavage, good quality embryo, clinical pregnancy and embryo implantation of group A1 were (72.72 +/- 3.35)%, (95.64 +/- 2.04)%, (24.39 +/- 4.57)%, 50.00% and 23.87%, respectively, while those of group A2 were (70.27 +/- 8.82)%, (94.82 +/- 4.94)%, (13.45 +/- 7.39)%, 9.52% and 6.25%, respectively, the latter three indexes remarkably higher in A1 than in A2 (P < 0.05), but the differences in the former two not statistically significant (P > 0.05). Before swim-up treatment, the above five indexes were (72.90 +/- 4.23)%, (95.20 +/- 2.61)%, (23.35 +/- 5.19)%, 39.58% and 18.35% in group B1, as compared with (71.33 +/- 5.10)%, (95.71 +/- 2.88)%, (20.18 +/- 6.15)%, 41.86% and 21.28% in group B2, with no statistically significant differences between the two groups (P > 0.05). CONCLUSION: The percentage of morphologically normal sperm after swim-up treatment on the day of oocyte retrieval may be a valuable predictor of the outcomes of IVF-ET.

[Alternate-day oral tadalafil for erectile dysfunction with no successful intercourse at the baseline].

OBJECTIVE: To summarize the experience in the treatment of erectile dysfunction (ED) with no successful intercourse at the baseline with tadalafil. METHODS: We retrospectively analyzed 21 cases of ED with no successful intercourse at the baseline treated with tadalafil on alternate days combined with sex guidance. RESULTS: After 4 weeks of tadalafil treatment, 19 of the patients achieved successful sexual intercourse, and the IIEF-5 score was remarkably improved as compared with pre-medication (3.24 +/- 1.55 vs 18.95 +/- 3.02, P<0.0001). Mild adverse reactions were observed in 6 cases, including 2 cases of mild headache and 4 cases of facial blush. CONCLUSION: Tadalafil on alternate days combined with sex guidance can significantly improve ED with no successful intercourse at the baseline.