Biogas Slurry Significantly Improved Degraded Farmland Soil Quality and Promoted Capsicum spp. Production.

This study reports on the effects of pretreated biogas slurry on degraded farm soil properties, microflora and the production of Capsicum spp. The responses of soil properties, microorganisms and Capsicum spp. production to biogas slurry pretreated soil were determined. The biogas slurry pretreatment of degraded soil increases the total nitrogen (0.15-0.32 g/kg), total phosphorus (0.13-0.75 g/kg), available phosphorus (102.62-190.68 mg/kg), available potassium (78.94-140.31 mg/kg), organic carbon content (0.67-3.32 g/kg) and pH value of the soil, while the population, diversity and distribution of soil bacteria and fungi were significantly affected. Interestingly, soil ammonium nitrogen, soil pH and soil nitrate nitrogen were highly correlated with the population of bacteria and fungi present in the pretreated soil. The soil with biogas slurry pretreatment of 495 m3/hm2 favored the seedling survival rate, flowering rate and fruit-bearing rate of Capsicum spp. and significantly reduced the rate of rigid seedlings. In this study, the application of 495 m3/hm2 biogas slurry to pretreat degraded soil has achieved the multiple goals of biogas slurry valorization, soil biofertilization and preventing and controlling plant diseases caused by soil-borne pathogenic microorganisms. These findings are of significant importance for the safe and environmentally friendly application of biogas slurry for soil pretreatment.

Effect of ultra-violet light radiation on Scenedesmus vacuolatus growth kinetics, metabolic performance, and preliminary biodegradation study.

This study presents the effect of ultra-violet (UV) light radiation on the process kinetics, metabolic performance, and biodegradation capability of Scenedesmus vacuolatus. The impact of the UV radiation on S. vacuolatus morphology, chlorophyll, carotenoid, carbohydrates, proteins, lipid accumulation, growth rate, substrate affinity and substrate versatility were evaluated. Thereafter, a preliminary biodegradative potential of UV-exposed S. vacuolatus on spent coolant waste (SCW) was carried out based on dehydrogenase activity (DHA) and total petroleum hydrocarbon degradation (TPH). Pronounced structural changes were observed in S. vacuolatus exposed to UV radiation for 24 h compared to the 2, 4, 6, 12 and 48 h UV exposure. Exposure of S. vacuolatus to UV radiation improved cellular chlorophyll (chla = 1.89-fold, chlb = 2.02-fold), carotenoid (1.24-fold), carbohydrates (4.62-fold), proteins (1.44-fold) and lipid accumulations (1.40-fold). In addition, the 24 h UV exposed S. vacuolatus showed a significant increase in substrate affinity (1/Ks) (0.959), specific growth rate (µ) (0.024 h-1) and biomass accumulation (0.513 g/L) by 1.50, 2 and 1.9-fold respectively. Moreover, enhanced DHA (55%) and TPH (100%) degradation efficiency were observed in UV-exposed S. vacuolatus. These findings provided major insights into the use of UV radiation to enhance S. vacuolatus biodegradative performance towards sustainable green environment negating the use of expensive chemicals and other unfriendly environmental practices.

Antimicrobial resistance expansion in pathogens: a review of current mitigation strategies and advances towards innovative therapy.

The escalating problem of antimicrobial resistance (AMR) proliferation in clinically important pathogens has become one of the biggest threats to human health and the global economy. Previous studies have estimated AMR-associated deaths and disability-adjusted life-years (DALYs) in many countries with a view to presenting a clearer picture of the global burden of AMR-related diseases. Recently, several novel strategies have been advanced to combat resistance spread. These include efflux activity inhibition, closing of mutant selection window (MSW), biofilm disruption, lytic bacteriophage particles, nanoantibiotics, engineered antimicrobial peptides, and the CRISPR-Cas9 gene-editing technique. The single or integrated deployment of these strategies has shown potentialities towards mitigating resistance and contributing to valuable therapeutic outcomes. Correspondingly, the new paradigm of personalized medicine demands innovative interventions such as improved and accurate point-of-care diagnosis and treatment to curtail AMR. The CRISPR-Cas system is a novel and highly promising nucleic acid detection and manipulating technology with the potential for application in the control of AMR. This review thus considers the specifics of some of the AMR-mitigating strategies, while noting their drawbacks, and discusses the advances in the CRISPR-based technology as an important point-of-care tool for tracking and curbing AMR in our fight against a looming 'post-antibiotic' era.

Developments and Prospects of Farmland Application of Biogas Slurry in China-A Review.

Biogas slurry (BS) is an attractive agricultural waste resource which can be used to regulate soil microbial communities, enhance nutrient absorption capacity of crops, promote plant-soil interactions, and consequently, increase crop productivity. Presently, BS discharge is not environmentally friendly. It is therefore necessary to explore alternative efficient utilization of BS. The use of BS as fertilizer meets the requirements for sustainable and eco-friendly development in agriculture, but this has not been fully actualized. Hence, this paper reviewed the advantages of using BS in farmland as soil fertilization for the improvement of crop production and quality. This review also highlighted the potential of BS for the prevention and control of soil acidification, salinization, as well as improve microbial structure and soil enzyme activity. Moreover, this review reports on the current techniques, application methods, relevant engineering measures, environmental benefits, challenges, and prospects associated with BS utilization. Lastly, additional research efforts require for optimal utilization of BS in farmlands were elucidated.

Hibiscus sabdariffa (Roselle) calyx: a systematic and meta-analytic review of memory-enhancing, anti-neuroinflammatory and antioxidative activities.

BACKGROUND: In this study, we summarized the preclinical investigations of the neuroprotective activities of Hibiscus sabdariffa (HSD) extract via its effect on memory function, neuroinflammation and oxidative damage in the central nervous system, which may help to guide future studies. METHODS: Preclinical studies that investigated the effect of HSD extract on memory impairment, neuroinflammation and oxidative stress-induced neuronal damage were searched systematically in PubMed, EBSCOhost (including MEDLINE, CINAHL, APA PsycInfo, etc.), Web of Science (WoS) and Scopus. Parameters and indexes included Morris water maze, passive avoidance test, acetylcholinesterase activity, interleukin 1 (IL-1), tumour necrosis factor-alpha (TNF-α), MAPK, malondialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS) and mitochondria membrane potential (MMP). RESULTS: A total of 285 documents were identified; however, only ten articles were included and used for meta-analysis. The meta-analytic outcome revealed that HSD did not show any significant effect on memory function, neuroinflammatory biomarkers (IL-1, MAPK) and oxidative stress (GSH, MDA, ROS and MMP) in neuronal cells and tissues. CONCLUSIONS: Individual study revealed that HSD showed improved memory function, attenuated neuroinflammation and prevented oxidative damage to neurons. However, a conflicting result was observed from the meta-analytic outcomes which showed that HSD has no significant effect on cognitive impairment, neuroinflammation and oxidative stress-induced neuronal damage. However the contradiction in this finding may be associated with small number of studies included. Hence, more studies on the memory-enhacing effects and anti-neuroinflammatory activity of HSD in preclinical and clinical model are required to validate its neuroprotective effect.

Effect of Crop Rotation on Fusarium Mycotoxins and Fusarium Species in Cereals in Sichuan Province (China).

The present study was performed to evaluate the effect of crop rotation on Fusarium mycotoxins and species in cereals in Sichuan Province. A total of 311 cereal samples were randomly collected and analyzed from 2018 to 2019 in Sichuan Province. The results of mycotoxin analysis showed that the major trichothecene mycotoxins in Sichuan Province were nivalenol (NIV) and deoxynivalenol (DON), and the mean concentration of total trichothecenes (including NIV, fusarenone X [4ANIV], DON, 3-acetyldeoxynivalenol [3ADON], and 15-acetyldeoxynivalenol [15ADON]) in wheat was significantly higher than that in maize and rice. The concentration of total trichothecenes in the succeeding crops was significantly higher than that in the previous crops. In addition, wheat grown after maize had reduced incidence and concentration of trichothecene mycotoxins compared with that grown after rice, and ratooning rice grown after rice had increased incidence and concentration of trichothecene mycotoxins. Our data indicated that Fusarium asiaticum with the NIV chemotype was predominant in wheat and rice samples, while the number of the NIV chemotypes of F. asiaticum and Fusarium meridionale and the 15ADON chemotype of Fusarium graminearum in maize were almost the same. Although the composition of Fusarium species was affected by crop rotations, there were no differences when comparing the same crop rotation except for the maize-wheat rotation. Moreover, the same species and chemotype of Fusarium strains originated from different crops in various rotations, but there were no significant differences in pathogenicity in wheat and rice. These results contribute to the knowledge of the effect of crop rotation on Fusarium mycotoxins and species affecting cereals in Sichuan Province, which may lead to improved strategies for control of Fusarium mycotoxins and fungal disease in China.

Antiproliferative and apoptosis-inducing effects of aqueous extracts from Ecklonia maxima and Ulva rigida on HepG2 cells.

This study examined the antiproliferative and apoptotic-inducing effects of Ecklonia maxima (KP) and Ulva rigida (URL) extracts in the human liver cancer (HepG2) cell line model. HepG2 cells were cultured and grown in an incubator (5% CO2 ) at 37°C. Cell viability was determined, while the effect of the extracts on apoptosis, ROS production, mitochondria membrane potential, and antioxidant enzymes were also assessed. KP and URL induced cytotoxic effects on HepG2 cells at the concentrations tested (0-1000 µg/ml). The morphological characteristics of the cells after treatment with KP and URL revealed cell shrinkage of the nucleus, cell injury, and damage compared to the control. The fluorescent micrographs from the apoptotic assay revealed induction of apoptosis and necrosis in HepG2 cells after treatment with KP and URL (200 and 400 µg/ml). The extracts also induced ROS production and reduced mitochondria membrane potential in HepG2 cells. The apoptotic-inducing effects, activation of ROS generation, and disruption of antioxidant enzymes are associated with the cytotoxic effects of the seaweed extracts. KP and URL showed good anticancer properties and could be explored as a good source of nutraceuticals, food additives, and dietary supplements to prevent uncontrolled proliferation of HepG2 cells. PRACTICAL APPLICATIONS: Seaweeds are reservoirs of nutrients and naturally occurring biologically active compounds, including sterols, phlorotannins, and polyunsaturated fatty acids. Due to the presence of these compounds, they are used as emulsifying agents, nutraceuticals, and additives in functional foods. Evidence suggests that seaweed bioactives may inhibit uncontrolled cell proliferation and induce apoptosis in cancer cells. Hence, exploring the antiproliferative and apoptotic-inducing effects of Ecklonia maxima and Ulva rigida will provide insights into their anticancer potentials as functional foods and nutraceuticals.

Vacuum Foam Drying Method Improved the Thermal Stability and Long-Term Shelf Life of a Live Attenuated Newcastle Disease Virus Vaccine.

Vaccines used for managing Newcastle disease virus (NDV) rely heavily on cold chain, and this results in major constraints in their successful application, shipping, and storage. This study was undertaken to improve the thermotolerance properties of live attenuated NDV vaccines using vacuum foam drying (VFD) technology. The live attenuated NDV vaccine formulated in 15% trehalose, 2.5% gelatin, 0.05% pluronic, and 25 mmol/L potassium phosphate buffer (T5) and dried using VFD showed improved heat tolerance in comparison to the vaccine formulated in T5 as well, but dried using freeze-drying (FD) method. The T5-formulated VFD vaccine was stored at 37°C for 120 days, 45°C for 7 days, and 60°C for 3 days; the virus titer loss decreased by no more than 1.0 Log10. In contrast, the FD vaccine prepared in T5 could only be stored at 37°C for 7-10 days. Furthermore, the T5-formulated NDV-VFD vaccine remained infectious when heated at 100°C for 30 min. Shelf-life studies confirmed the improved thermal tolerance of the T5-formulated NDV-VFD vaccine since it could be stably stored at 2-8°C for 42 months and 25°C for 15 months. Moreover, immunization of 1-month-old specific pathogen-free (SPF) chickens with the T5-formulated NDV-VFD vaccine stored at 25 and 37°C could produce hemagglutination inhibition (HI) antibody levels comparable to those of commercial NDV-FD vaccines, which require strict adherence to the cold chain. In conclusion, not only did the VFD technology improve the thermostability and long-term shelf life of the vaccine, it also maintained its immunogenicity.

Genetic heterogeneity of group A rotaviruses: a review of the evolutionary dynamics and implication on vaccination.

INTRODUCTION: Human rotavirus remains a major etiology of acute gastroenteritis among under 5-year children worldwide despite the availability of oral vaccines. The genetic instability of rotavirus and the ability to form different combinations from the different G- and P-types reshapes the antigenic landscape of emerging strains which often display limited or no antigen identities with the vaccine strain. As evidence also suggests, the selection of the antigenically distinct novel or rare strains and their successful spread in the human population has raised concerns regarding undermining the effectiveness of vaccination programs. AREAS COVERED: We review aspects related to current knowledge about genetic and antigenic heterogeneity of rotavirus, the mechanism of genetic diversity and evolution, and the implication of genetic change on vaccination. EXPERT OPINION: Genetic changes in the segmented genome of rotavirus can alter the antigenic landscape on the virion capsid and further promote viral fitness in a fully vaccinated population. Against this background, the potential risk of the appearance of new rotavirus strains over the long term would be better predicted by a continued and increased close monitoring of the variants across the globe to identify any change associated with disease dynamics.

Neurotoxicity of Polycyclic Aromatic Hydrocarbons: A Systematic Mapping and Review of Neuropathological Mechanisms.

Several studies present the neurotoxic effects of polycyclic aromatic hydrocarbons (PAHs), a class of environmental pollutants capable of causing neurological deficits. However, a collective review approach to this research topic is scarce. This study presents the effect of PAHs on the central nervous system using a bibliometric approach. The neuropathological mechanisms of PAHs are also highlighted. Published articles were searched for in the Scopus and Web of Science databases from January 1979 to December 2020 using the keywords 'polycyclic aromatic hydrocarbons' and 'neurotoxicity'. The total number of documents retrieved from both databases was 338. Duplicated documents (80) were excluded and 258 articles were used for the final analysis. Our findings revealed that there has been a significant increase in research outputs on this topic in the last ten years. The countries with the highest scientific productivity in this area are USA, China, France and Italy. The result also showed that, in the past few years, global scientific output in research relating to PAH neurotoxicity focused on neurodegeneration, cholinergic function, neurodevelopmental toxicity, behavioural studies, oxidative stress, neuroprotection and therapeutic intervention using different experimental models, including zebrafish, neuronal cell lines, Caenorhabditis elegans and rats. Recent studies also revealed the neuroprotective roles of some natural products against PAH-induced neurotoxicity. However, more investigation involving clinical trials is required to emphasize the observed neurotoxic effects.

Neurotoxicity of anthracene and benz[a]anthracene involves oxidative stress-induced neuronal damage, cholinergic dysfunction and disruption of monoaminergic and purinergic enzymes.

In this study, the modulatory effects of anthracene (ANT) and benz[a]anthracene (BEN) on biochemical markers associated with neurodegeneration were assessed in mouse hippocampal neuronal cells (HT-22). Neuronal cells were cultured and exposed to ANT and BEN (25-125 µM) for 5 days, and the cell viability was determined via MTT assay. Morphological characteristics of the cells were assessed using a compound microscope. Biochemical parameters such as acetylcholinesterase (AChE), monoamine oxidase (MAO) and adenosine deaminase (ADA) activities as well as oxidative stress biomarkers (catalase [CAT], glutathione -S- transferase [GST] activities and Glutathione [GSH] levels) and nitric oxide [NO] levels were assessed after cells were treated with ANT and BEN for two days. The results showed that cell viability reduced with an increase in exposure time. After the fifth day of treatment, BEN and ANT (125 µM) reduced percentage viability to 41 and 38.1%, respectively. Light micrographs showed shrinkage of cells, neuronal injury and cell death in cells treated with higher concentrations of BEN and ANT (50 and 125 µM). Furthermore, AChE and MAO activities reduced significantly after treatment for 48 h with ANT and BEN. A significant decrease in CAT and GST activities and low GSH levels were observed after treatment with BEN and ANT. However, both polycyclic aromatic hydrocarbons caused a significant increase in ADA activity and NO levels. These results suggest that ANT and BEN may induce neurodegeneration in neuronal cells via oxidative stress-induced-neuronal injury, disruption of cholinergic, monoaminergic and purinergic transmission, and increased nitric oxide levels.

Does Chlorination Promote Antimicrobial Resistance in Waterborne Pathogens? Mechanistic Insight into Co-Resistance and Its Implication for Public Health.

Chemical agents including chlorine and antibiotics are used extensively to control infectious microorganisms. While antibiotics are mainly used to treat bacterial infections, chlorine is widely used for microbial inactivation in the post-secondary disinfection steps of water treatment. The extensive use of these agents has been acknowledged as a driving force for the expansion of antimicrobial resistance (AMR) and has prompted discourse on their roles in the evolution and proliferation of resistant pathogens in the aquatic milieus. We live in a possible "post-antibiotic" era when resistant microbes spread at startling levels with dire predictions relating to a potential lack of effective therapeutic antibacterial drugs. There have been reports of enhancement of resistance among some waterborne pathogens due to chlorination. In this context, it is pertinent to investigate the various factors and mechanisms underlying the emergence and spread of resistance and the possible association between chlorination and AMR. We, therefore, reflect on the specifics of bacterial resistance development, the mechanisms of intrinsic and acquired resistance with emphasis on their environmental and public health implications, the co-selection for antibiotic resistance due to chlorination, biofilm microbiology, and multidrug efflux activity. In-depth knowledge of the molecular basis of resistance development in bacteria will significantly contribute to the more rational utilization of these biocidal agents and aid in filling identified knowledge gap toward curbing resistance expansion.

Rotaviruses: From Pathogenesis to Disease Control-A Critical Review.

Since their first recognition in human cases about four decades ago, rotaviruses have remained the leading cause of acute severe dehydrating diarrhea among infants and young children worldwide. The WHO prequalification of oral rotavirus vaccines (ORV) a decade ago and its introduction in many countries have yielded a significant decline in the global burden of the disease, although not without challenges to achieving global effectiveness. Poised by the unending malady of rotavirus diarrhea and the attributable death cases in developing countries, we provide detailed insights into rotavirus biology, exposure pathways, cellular receptors and pathogenesis, host immune response, epidemiology, and vaccination. Additionally, recent developments on the various host, viral and environmental associated factors impacting ORV performance in low-and middle-income countries (LMIC) are reviewed and their significance assessed. In addition, we review the advances in nonvaccine strategies (probiotics, candidate anti-rotaviral drugs, breastfeeding) to disease prevention and management.

Dysbiosis and intestinal inflammation caused by Salmonella Typhimurium in mice can be alleviated by preadministration of a lytic phage.

Many studies have shown the efficacy of phage therapy in reducing intestinal pathogens. However, phage-based probiotic treatment is poorly studied in view of effects on the gut microbiota and intestinal inflammation. In this study, a lytic or a temperate phage (each at 4 ×108 PFU per day) or a streptomycin solution (40 mg per day) were administered to mice via drinking water for 31 days. Subsequently, mice were challenged with Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium). S. Typhimurium does not serve as the host bacterium and is not lysed by both phages. For intestinal inflammation evaluation, mice were given one dose of streptomycin for 24 h before the S. Typhimurium challenge. High-throughput sequencing analysis revealed that the phylum Firmicutes became the most abundant in mice pretreated with phages. The alpha diversity of gut bacteria was higher in phage treated than in streptomycin treated mice. Moreover, pretreatment with the lytic and the temperate phage before the S. Typhimurium challenge increased two beneficial genera, Lactobacillus and Bifidobacterium. According to the pathological analysis of ileum, cecum, and serum, temperate or lytic gut phage pretreatment of mice markedly reduced intestinal inflammation, concomitant with lower serum concentration of lipopolysaccharides (LPS) and diamine oxidase (DAO). The oral pretreatments of mice (ST, Lyt, Lys, SM) generally caused an increased expression of IL-1ß, TNF-α, IFN-γ, IL-4, and IL-10 compared to the matching control. However, in mice pretreated with the lytic phage, the mRNA expression for the pro-inflammatory cytokine TNF-α was not significantly higher than that of the control group. No significant differences were detected for peripheral blood B lymphocytes, CD3 +T cells, and the CD4 + /CD8 + ratio in mice pretreated with the lytic and lysogenic phage. This study demonstrated that even lytic phages not targeting the pathogenic serovar Salmonella Typhimurium alleviated intestinal dysbiosis and inflammation in challenged mice.

Virulence and Inoculation Route Influence the Consequences of Mycoplasma hyorhinis Infection in Bama Miniature Pigs.

Mycoplasma hyorhinis is a widespread pathogen in pig farms worldwide. Although the majority of M. hyorhinis-colonized pigs have no apparent clinical disease, the pathogen can induce diseases such as polyserositis, arthritis, and eustachitis in some cases. To explore the mechanisms for the occurrence of these diseases, we challenged 4 groups of Bama miniature pigs with M. hyorhinis isolated from pigs without clinical symptoms (non-clinical origin [NCO] strain) or with typical clinical symptoms (clinical origin [CO] strain) and investigated the impacts of different strains and inoculation routes (intranasal [IN], intravenous [IV] + intraperitoneal [IP], and IV+IP+IN) on disease induction. Another group of pigs was set as a negative control. Pigs inoculated with the CO strain through a combined intravenous and intraperitoneal (IV+IP) route showed a significant decrease in average daily weight gain (ADWG), serious joint swelling, and lameness compared with the pigs in the negative-control group. Furthermore, this group developed moderate-to-severe pericarditis, pleuritis, peritonitis, and arthritis, as well as high levels of IgG and IgM antibodies. Pigs inoculated IV+IP with the NCO strain developed less marked clinical, pathological changes and a weaker specific antibody response compared with the pigs inoculated with the CO strain. The challenging results of the NCO strain via different routes (IV+IP, IV+IP+IN, and IN) indicated that the combined route (IV+IP) induced the most serious disease compared to the other inoculation routes. Intranasal inoculation induced a smaller decrease in ADWG without obvious polyserositis or arthritis. These data suggest that differences in both strain virulence and inoculation route affect the consequences of M. hyorhinis infection. IMPORTANCE Mycoplasma hyorhinis is a widespread pathogen in pig farms worldwide. The mechanisms or conditions that lead to the occurrence of disease in M. hyorhinis-infected pigs are still unknown. The objective of this study was to evaluate the impact of differences in the virulence of strain and the inoculation route on the consequences of M. hyorhinis infection.

A multifunctional enolase mediates cytoadhesion and interaction with host plasminogen and fibronectin in Mycoplasma hyorhinis.

Mycoplasma hyorhinis may cause systemic inflammation of pigs, typically polyserositis and arthritis, and is also associated with several types of human cancer. However, the pathogenesis of M. hyorhinis colonizing and breaching the respiratory barrier to establish systemic infection is poorly understood. Glycolytic enzymes are important moonlighting proteins and virulence-related factors in various bacteria. In this study, we investigated the functions of a glycolytic critical enzyme, enolase in the infection and systemic spread of M. hyorhinis. Bacterial surface localization of enolase was confirmed by flow cytometry and colony hybridization assay. Recombinant M. hyorhinis enolase (rEno) was found to adhere to pig kidney (PK-15) cells, and anti-rEno serum significantly decreased adherence. The enzyme was also found to bind host plasminogen and fibronectin, and interactions were specific and strong, with dissociation constant (KD) values of 1.4 nM and 14.3 nM, respectively, from surface plasmon resonance analysis. Activation of rEno-bound plasminogen was confirmed by its ability to hydrolyze plasmin-specific substrates and to degrade a reconstituted extracellular matrix. To explore key sites during these interactions, C-terminal lysine residues of enolase were replaced with leucine, and the resulting single-site and double-site mutants show significantly reduced interaction with plasminogen in far-Western blotting and surface plasmon resonance tests. The binding affinities of all mutants to fibronectin were reduced as well. Collectively, these results imply that enolase moonlights as an important adhesin of M. hyorhinis, and interacts with plasminogen and fibronectin. The two lysine residues in the C-terminus are important binding sites for its multiple binding activities.

Epidemiological significance of the occurrence and persistence of rotaviruses in water and sewage: a critical review and proposal for routine microbiological monitoring.

Globally, waterborne gastroenteritis attributable to rotaviruses is on the increase due to the rapid increase in population growth, poor socioeconomic conditions, and drastic changes in climatic conditions. The burden of diarrhea is quite alarming in developing nations where the majority of the populations still rely on untreated surface water that is usually polluted for their immediate water needs. Humans and animals of all ages are affected by rotaviruses. In humans, the preponderance of cases occurs in children under 5 years. Global efforts in advancing water/wastewater treatment technologies have not yet realized the objective of complete viral removal from wastewater. Most times, surface waters are impacted heavily by inadequately treated wastewater run-offs thereby exposing people or animals to preventable health risks. The relative stability of rotaviruses in aquatic matrices during wastewater treatment, poor correlation of bacteriological indicators with the presence of rotaviruses, and their infectiousness at a low dose informed the proposal for inclusion in the routine microbiological water screening panel. Environmental monitoring data have been shown to provide early warnings that can complement clinical data used to monitor the impact of current rotavirus vaccination in a community. This review was therefore undertaken to critically appraise rotavirus excretion and emission pathways, and the existence, viability and persistence in the receiving aquatic milieu. The efficiency of the current wastewater treatment modality for rotavirus removal, correlation of the current bacteriological water quality assessment strategy, public health risks and current laboratory methods for an epidemiological study were also discussed.

Classic Pentachlorophenol Hydroxylating Phenylalanine 4-Monooxygenase from Indigenous Bacillus tropicus Strain AOA-CPS1: Cloning, Overexpression, Purification, Characterization and Structural Homology Modelling.

The metabolically promiscuous pentachlorophenol (PCP) hydroxylating Phe4MO (represented as CpsB) was detected, amplified (from the genome of Bacillus tropicus strain AOA-CPS1), cloned, overexpressed, purified and characterized here. The 1.755-kb gene cloned in the pET15b vector expressed a ≅ 64 kDa monomeric protein which was purified to homogeneity by single-step affinity chromatography, with a total yield of 82.1%. The optimum temperature and pH of the enzyme were found to be 30 °C and 7.0, respectively. CpsB showed functional stability between pH 6.0-7.5 and temperature 25-30 °C. The enzyme-substrate reaction kinetic studies showed the allosteric nature of the enzyme and followed pre-steady state using NADH as a co-substrate with apparent vmax, Km, kcat and kcat/Km values of 0.465 µM.s-1, 140 µM, 0.099 s-1 and 7.07 × 10-4 µM-1.s-1, respectively, for the substrate PCP. The in-gel trypsin digestion experiments and bioinformatic tools confirmed that the reported enzyme is a Phe4MO with multiple putative conserved domains and metal ion-binding site. Though Phe4MO has been reported to have a diverse catalytic function, here we report, for the first time, that it functions as a PCP dehalogenase or PCP-4-monooxygenase by hydroxylating PCP. Hence, the use of this enzyme may be further explored in the bioremediation of PCP and other related xenobiotics.

Applications of Lactic Acid Bacteria and Their Bacteriocins against Food Spoilage Microorganisms and Foodborne Pathogens.

Lactic acid bacteria (LAB) are Gram-positive and catalase-negative microorganisms used to produce fermented foods. They appear morphologically as cocci or rods and they do not form spores. LAB used in food fermentation are from the Lactobacillus and Bifidobacterium genera and are useful in controlling spoilage and pathogenic microbes, due to the bacteriocins and acids that they produce. Consequently, LAB and their bacteriocins have emerged as viable alternatives to chemical food preservatives, curtesy of their qualified presumption of safety (QPS) status. There is growing interest regarding updated literature on the applications of LAB and their products in food safety, inhibition of the proliferation of food spoilage microbes and foodborne pathogens, and the mitigation of viral infections associated with food, as well as in the development of creative food packaging materials. Therefore, this review explores empirical studies, documenting applications and the extent to which LAB isolates and their bacteriocins have been used in the food industry against food spoilage microorganisms and foodborne pathogens including viruses; as well as to highlight the prospects of their numerous novel applications as components of hurdle technology to provide safe and quality food products.

Prevalence, Pattern and Genetic Diversity of Rotaviruses among Children under 5 Years of Age with Acute Gastroenteritis in South Africa: A Systematic Review and Meta-Analysis.

Rotavirus is the most significant cause of severe acute gastroenteritis among children under 5 years of age, worldwide. Sub-Saharan Africa particularly bears the brunt of the diarrheal deaths. A meta-analysis was conducted on 43 eligible studies published between 1982 and 2020 to estimate the pooled prevalence of rotavirus infection and changes in the main rotavirus strains circulating before and after vaccine introduction among under-five children in South Africa. The pooled national prevalence of rotavirus infection was estimated at 24% (95% CI: 21-27%) for the pre-vaccination period and decreased to 23% (95% CI: 21-25%) in the post-vaccination period. However, an increased number of cases was observed in the KwaZulu-Natal (21-28%) and Western Cape (18-24%) regions post-vaccination. The most dominant genotype combinations in the pre-vaccine era was G1P[8], followed by G2P[4], G3P[8], and G1P[6]. After vaccine introduction, a greater genotype diversity was observed, with G9P[8] emerging as the predominant genotype combination, followed by G2P[4], G12P[8], and G1P[8]. The introduction of the rotavirus vaccine was associated with a reduction in the burden of rotavirus-associated diarrhea in South Africa, although not without regional fluctuation. The observed changing patterns of genotype distribution highlights the need for ongoing surveillance to monitor the disease trend and to identify any potential effects associated with the dynamics of genotype changes on vaccine pressure/failure.