Cell Culture Adaptive Amino Acid Substitutions in FMDV Structural Proteins: A Key Mechanism for Altered Receptor Tropism.

The foot-and-mouth disease virus is a highly contagious and economically devastating virus of cloven-hooved animals, including cattle, buffalo, sheep, and goats, causing reduced animal productivity and posing international trade restrictions. For decades, chemically inactivated vaccines have been serving as the most effective strategy for the management of foot-and-mouth disease. Inactivated vaccines are commercially produced in cell culture systems, which require successful propagation and adaptation of field isolates, demanding a high cost and laborious time. Cell culture adaptation is chiefly indebted to amino acid substitutions in surface-exposed capsid proteins, altering the necessity of RGD-dependent receptors to heparan sulfate macromolecules for virus binding. Several amino acid substations in VP1, VP2, and VP3 capsid proteins of FMDV, both at structural and functional levels, have been characterized previously. This literature review combines frequently reported amino acid substitutions in virus capsid proteins, their critical roles in virus adaptation, and functional characterization of the substitutions. Furthermore, this data can facilitate molecular virologists to develop new vaccine strains against the foot-and-mouth disease virus, revolutionizing vaccinology via reverse genetic engineering and synthetic biology.

Membrane reciprocation and quorum quenching: An innovative combination for fouling control and energy saving in membrane bioreactors.

Membrane bioreactors (MBRs) play a crucial role in wastewater treatment, but they face considerable challenges due to fouling. To tackle this issue, innovative strategies are needed. This study investigated the effectiveness of membrane reciprocation and quorum quenching (QQ) to control fouling in MBRs. The study compared MBRs using membrane reciprocation (30 rpm) and QQ (injecting media containing 100 or 200 mg/L BH4) with conventional MBRs employing different air-scouring intensities. The results demonstrated that combining membrane reciprocation (30 rpm) with QQ (200 mg/L BH4) significantly extended the service time of MBRs, making it approximately six times longer than conventional methods. Moreover, this approach reduced physically reversible resistance. The reduction in signal molecules related to biofouling due to QQ showcased its critical role in controlling biofouling, even under high shear caused by membrane reciprocation. However, the impact of QQ on microbial community structure appeared relatively insignificant when compared to factors such as operation time, aeration intensity, and membrane reciprocation. By combining membrane reciprocation and QQ, the study achieved a remarkable 81 % energy saving compared to extensive aeration (103 s-1 in velocity gradient), in addition to the extended service time. Importantly, this combined antifouling approach did not negatively affect microbial characteristics and wastewater treatment, emphasizing its effectiveness in MBRs. Overall, the findings of this study offer valuable insights for developing synergistic fouling control strategies in MBRs, significantly improving the energy efficiency of the wastewater treatment process.

The relationship between quorum sensing dynamics and biological performances during anaerobic membrane bioreactor treatment.

Anaerobic membrane bioreactors (AnMBRs) enhance carbon neutrality with biomethane recovery from wastewater; however, microbial signaling, which may affect biological performances, was poorly understood. Here, we thus evaluate quorum sensing (QS) dynamics while monitoring acyl-homoserine lactones (AHLs) and autoinducer-2 (AI-2) levels during long-term AnMBR operations after sludge inoculation. Significant organic removal and methane production were achieved with the reactor startup. Signal molecule levels varied with transient organic loading rates, depending on their types. A starving condition may cause an increase in short- and medium-chain AHLs and AI-2. Biopolymers, biosolids, volatile fatty acids, and alkalinity levels had positive correlations with short- and medium-chain AHLs and AI-2, whereas methane production had positive correlations with long-chain AHLs. The principal component analysis of QS signal composition and biological performance data explains their interconnectivity. The findings of this study help to understand that QS signals regulate metabolic pathways in addition to microbial group behaviors.

Layered Antibiofouling Composite Membrane for Quenching Bacterial Signaling.

Bacterial quorum quenching (QQ) media with various structures (e.g., bead, cylinder, hollow cylinder, and sheet), which impart biofouling mitigation in membrane bioreactors (MBRs), have been reported. However, there has been a continuous demand for membranes with QQ capability. Thus, herein, we report a novel double-layered membrane comprising an outer layer containing a QQ bacterium (BH4 strain) on the polysulfone hollow fiber membrane. The double-layered composite membrane significantly inhibits biofilm formation (i.e., the biofilm density decreases by ~58%), biopolymer accumulation (e.g., polysaccharide), and signal molecule concentration (which decreases by ~38%) on the membrane surface. The transmembrane pressure buildup to 50 kPa of the BH4-embedded membrane (17.8 h ± 1.1) is delayed by more than thrice (p < 0.05) of the control with no BH4 in the membrane's outer layer (5.5 h ± 0.8). This finding provides new insight into fabricating antibiofouling membranes with a self-regulating property against biofilm growth.

Isolation and characterization of novel indigenous facultative quorum quenching bacterial strains for ambidextrous biofouling control.

Quorum quenching (QQ), the disruption of microbial communication, has proven to be effective as an innovative anti-biofouling strategy for membrane bioreactors (MBRs). However, QQ bacteria for anaerobic environments have not been extensively analyzed in previous research. This study thus investigated facultative QQ bacterial strains that exhibit potential for use in aerobic and anaerobic MBRs. Two novel QQ strains from the genus Pseudomonas (KS2 and KS10) were isolated from anaerobic digester sludge using signal molecules as the sole carbon source. The two QQ strains exhibited significant signal molecule degradation depending on the oxygen levels and demonstrated endogenous QQ activity, with KS2 producing lactonase and KS10 producing acylase. The QQ strains significantly reduced the formation of the biofilm generated by both Pseudomonas aeruginosa (PAO1) and real sludge. Facultative QQ strains have the potential to offer a more flexible option for effective biofouling control in both aerobic and anaerobic MBRs.

Correlation of plasma kisspeptin with total testosterone levels in smokeless tobacco and smoking tobacco users in a healthy cohort: A cross-sectional study.

Human infertility is a worldwide health issue and is the inability to conceive following twelve months of unprotected sexual intercourse. Consistent studies reiterated tobacco abuse to be an important risk factor which adversely effects male fertility. This study aims to determine the correlation of kisspeptin and total testosterone levels in smokeless tobacco, smoking tobacco users and healthy controls. A total of 180 subjects were selected using random sampling technique. Non-fasting blood samples (5 ml) were drawn, and ELISA technique was used for the evaluation of plasma levels of kisspeptin and total testosterone. Total testosterone was found to be significantly high in smokers and smokeless tobacco users, while the level of kisspeptin was found to be significantly high in smokeless tobacco users only as compared to control group. Furthermore, the level of cholesterol was found to be significantly low, whereas HDL and triglycerides were found to be significantly high in smokeless tobacco users relative to control subjects. Findings of this study suggest that tobacco use has impact on HPG axis by affecting kisspeptin level. The increase in kisspeptin level can affect hypothalamic function leading to pituitary and gonadal dysfunction along with impairment of reproduction. The finding that smokeless tobacco significantly raises kisspeptin strengthens the idea that smokeless tobacco use has more potent effects centrally compared to smoking.