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Glucoselipid biosurfactant biosynthesis operon of rouxiella badensis DSM 100043T: screening, identification, and heterologous expression in escherichia coli
No full textRouxiella badensis DSM 100043T had been previously proven to produce a novel glucoselipid biosurfactant which has a very low critical micelle concentration (CMC) as well as very good stability against a wide range of pH, temperature, and salinity. In this study, we performed a function-based library screening from a R. badensis DSM 100043T genome library to identify responsible genes for biosynthesis of this glucoselipid. The identified open reading frames (ORFs) were cloned into several constructs in Escherichia coli for gene permutation analysis and the individual products were analyzed using high-performance thin-layer chromatography (HPTLC). Products of interest from positive expression strains were purified and analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) and nuclear magnetic resonance (NMR) for further structure elucidation. Function-based screening of 5400 clones led to the identification of an operon containing three ORFs encoding acetyltransferase GlcA (ORF1), acyltransferase GlcB (ORF2), and phosphatase/HAD GlcC (ORF3). E. coli pCAT2, with all three ORFs, resulted in the production of identical R. badensis DSM 100043T glucosedilipid with Glu-C10:0-C12:1 as the main congener. ORF2-deletion strain E. coli pAFP1 primarily produced glucosemonolipids, with Glu-C10:0,3OH and Glu-C12:0 as the major congeners, predominantly esterified at the C-2 position of the glucose moiety. Furthermore, fed-batch bioreactor cultivation of E. coli pCAT2 using glucose as the carbon source yielded a maximum glucosedilipid titer of 2.34 g/L after 25 h of fermentation, which is 55-fold higher than that produced by batch cultivation of R. badensis DSM 100043T in the previous study
Obesity, beverage consumption and sleep patterns in rural african women in relation to advertising of these beverages
No full textBackground: The burden of obesity-related, non-communicable diseases in South Africa is persistent, with poor and black South African women particularly vulnerable. The purpose of the present study was to determine relationships between obesity, physical activity, sleep patterns and beverage consumption among black South African women in a rural village in the Limpopo province. Methods: A cross-sectional study was conducted among 200 rural-dwelling African women. Data were collected on beverage consumption, sociodemographic information, sleep patterns and anthropometry using self-reported questionnaires. Results: The mean body mass index (BMI) was 28.5±7.3 kg/m2, with 40% being classified as obese (BMI ≥30 kg/m2) and the mean sleep score was 4.68±2.51. Participants with very bad habitual sleeping patterns consumed significantly more sugar-sweetened beverages and alcohol than those with very good sleeping patterns. We also observed that when total coffee with sugar, fruit juice, total sugar-sweetened beverages and weight decreased the number of hours participants slept increased. Conclusions: The study identified significant associations between body weight, sleep duration and sugar-sweetened beverage consumption among rural black South African women. This underscores a need to address unhealthy lifestyle behaviours to lower incidences of non-communicable diseases in rural-dwelling women
A validation of fruitlook data using eddy covariance in a fully mature and high-density japanese plum orchard in the western cape, south africa
No full textThe cultivation of Japanese plums (Prunus salicina Lindl.) in South Africa has increased over the years, yet their water use is unknown. Their cultivation in the Western Cape Province of South Africa is highly dependent on supplementary irrigation, indicating their high water use demand. This study used remote sensing techniques to estimate the actual evapotranspiration (ETc act) of the Japanese plums to assess their water use on a large scale. The accuracy of the procedure had to be validated before getting to tangible conclusions. The eddy covariance was used to measure ETc act in an African Delight plum orchard to validate the FruitLook remote sensing data for the 2023–2024 hydrological year and irrigation season. The seasonal and annual plum crop water requirements measured using the eddy covariance system were 751 and 996 mm, while those estimated by FruitLook were 744 and 948 mm, respectively. Although FruitLook slightly underestimated plum ETc act by a Pbias of −6.15%, it performed well with a Nash–Sutcliffe efficiency (NSE) of 0.91. FruitLook underestimated evapotranspiration mainly during the peak summer season with full vegetation cover when the model may inaccurately represent irrigation impacts, soil moisture availability, and localized advection effects, better captured by the eddy covariance system. Based on the results, FruitLook proved to be sufficiently accurate for large-scale applications to estimate evapotranspiration in Japanese plum orchards in the Western Cape
Substituting for the state: the sovereignty impacts of diverse citizens’ off‐grid infrastructure strategies in South Africa
No full textIn South Africa, citizens in both low‐ and high‐income areas are increasingly providing their own services to mitigate the unreliability, unaffordability and inaccessibility of state services. This article examines diverse case studies across socio‐economic and residential typologies to explore shifts in service provision responsibilities from the state to the citizen. Applying an interdisciplinary approach, this article considers the political impacts of these strategies, arguing that the ways in which citizens supplement and substitute for the state contests and (re)negotiates spaces of sovereignty. While urban studies overwhelmingly analyse these actions through the lens of informality, we argue that sovereignty (the supreme authority of a state to govern itself without external interference) offers a less binary analytical lens. State substitution is increasingly a daily act for many, not only in low‐income settlements but also among elites. The article further examines state responses to citizen‐led actions in supplementing or substituting services, demonstrating how they range from inaction to permissive negotiation and, rarely, repression. Thus, the political impact of service substitution requires deeper reflection, raising questions regarding the nature of the state and the social contract
Experiences of adolescents living with HIV on transitioning from pediatric to adult HIV care in low- and middle-income countries: a qualitative evidence synthesis
No full text(1) Background: Adolescents living with HIV (ALHIVs) experience significant challenges in adhering to treatment and remaining engaged in care as they transition from pediatric to adult HIV care programs. The aim of this qualitative evidence synthesis (QES) was to review qualitative studies that describe how ALHIVs experience transition practices in low- and middle-income countries. (2) Methods: The following databases were searched: PubMed, Wiley Library Online, EbscoHost (PsychARTICLES, MEDLINE, Scopus, CINAHL), the WHO database, Google Scholar, and reference mining of the included studies. The inclusion criteria were as follows: ALHIV 10–19 years old, interventions on the transition period or studies describing transition practices, published between 2012 and 2023, conducted in low- and middle-income countries, English language, and qualitative and mixed-method studies. This review adheres to the PRISMA guidelines. CASP and MMAT were used for methodological quality assessment, and GRADE CERQual was used for the confidence in review findings. (3) Results: Seven articles were included in the final review. The five overarching themes described: (1) transition readiness during the pre-transition phase; (2) structural (health systems) barriers and treatment literacy as challenges during the transition period; and (3) provided accounts of successful post-transition experiences and recommendations for improving the transition process (when these were not experienced as positive), while also describing the individual and collective contexts in which transition took place, as they outlined (4) individual (psychological) barriers and the facilitative role that (5) a supportive environment played in the outcome of the transition process. There was a high level of confidence in transition readiness, while the other themes were assessed as having moderate confidence due to methodological limitations and minor concerns about adequacy or relevance. (4) Conclusions: There is a dearth of qualitative studies on the transition experiences of ALHIVs and on how the transition process impacts adherence, retention in care, and mental well-being. We recommend the development of interventions in the form of a guided transition protocol to improve the transition experiences of ALHIVs
Assessing the impacts of water diversion project on water resource system sustainability
No full textInterbasin water diversion project has been considered as an effective way to assure water resource system sustainability. In order to assess the impacts of water diversion on sustainability, we propose a framework in terms of reliability, resilience, and vulnerability. The estimated water availability from hydrological models and the projected water demand are input to a water resource allocation model. The water resource allocation model allocates the two available water sources (i.e., the local and the diverted water) in the water-receiving areas. The differences of the allocated water resources between these two water sources are figured out to quantify the impacts of water diversion on water resource system sustainability. The water-receiving area of Bailong River Water Diversion Project, located in Gansu, China, was selected as a case study. The results show that compared to the reference planning years, the runoff in future planning years will be reduced, while their water demands will almost increase under all scenarios. Although the current designed water diversion scheme is effective in increasing resilience, there is still potential for increasing resilience through optimizing the designed scheme. Further, the more unfavorable the water supply and demand conditions are, the larger the space for optimizing the system sustainability. This study can help understand the impacts of water diversion on water resource system sustainability in a changing environment
Internal migration and the impact on the Driftsands Nature Reserve due to COVID 19: a case study perspective
No full textUnplanned informal communities with subpar living conditions are frequently formed by illegal land occupation in all cities. However, these settlements are especially troubling in cities that are rapidly urbanising in lower-income nations since urban growth rates frequently surpass rates of infrastructure development. (Capps, Bentsen, & Ramí, 2015). The effect of COVID-19 on lower-income households has also been detrimental in the Cape Metro. Due to the different lockdown levels, it was more difficult for people to get work and for those living in backyards who couldn't afford rent to be evicted legally. The backyard residents then moved to the neighbouring Driftsands Nature Reserve from their evicted residences, resulting in an illegal and unauthorised invasion of the nature reserve. In addition to causing irreparable ecological harm and ruining the environment, this action resulted in the declassification of the once-thriving environmental education reserve and the loss of its Nature Reserve designation. The objective of this study is to assess the migration of individuals who were unlawfully occupying land in the Driftsands Nature Reserve using Lee's Theory of Migration and also taking into account the impact that COVID-19 had on the migrants (Lee, 1966)
Phytochemical characterization and cytotoxicity effects of Hyptis suaveolens collected in Nigeria
No full textHyptis suaveleons (L.) Poit. belongs to the Laminaceae family. This weed, native to tropical America, has become widespread in tropical regions worldwide. In folk medicine, plant extracts are used in the treatment of wounds, peptic ulcers, respiratory tract infections, and skin diseases among others. Thus, the importance of assessing the toxicity of plants for any human use cannot be overstated. This study analyzed the phytochemical properties of the Nigerian H. suaveleons population and assessed its cytotoxicity. Six bioactive compounds were isolated from the acetone extract of the H. suaveolens plant using silica gel column chromatography, one of which is new from natural sources. The isolated compounds were identified as 14-O-acetyl suaveolol (C1), suaveolol (C2), suaveolic acid (C3), dehydroabietinol (C4), maniladiol (C5), and β-sitosterol (C6) based on 1D and 2D NMR spectroscopic data. The MTT assay was used to assess the cytotoxicity effects of these metabolites on HepG2, KMST-6, and HaCaT cells. Among them, C1 significantly reduced HepG2, KMST-6, and HaCaT cell viability with IC50 values of 35.97, 43.48, and 65.10 µg/ml, respectively. The study suggests C1 has promising anticancer properties, possibly due to the acetyl group on C-14, while C2, suaveolol, lacks this group, and did not yield any inhibitory activities. However, further research is needed to understand its mechanisms
Trimetallic chalcogenide-sensitised interferon gamma aptasensor for tuberculosis
No full textNovel copper indium tin sulfide nanomaterial synthesized with chitosan capping agent.•IFN-γ TB biomarker aptasensor was fabricated using a χt-c-CITS sensing platform.•By aptamer surface density study, χt-c-CITS enhanced aptamer loading by 84.6 %.•χt-c-CITS increased aptasensor signal by 73.9 % and target detection by 85.7 %.•"Turn-on" assay format was achieved and monitored by capacitive charge measurements. Tuberculosis (TB) is a highly contagious disease whose eradication has become challenging due to the difficulty of early and real-time diagnosis, especially in developing countries. These challenges arise due to the time-consuming, expensive, complicated, and non-user-friendly nature of the current diagnostic techniques, making them difficult to use except by a highly trained medical laboratory specialist. Since biosensors offer a faster, simpler, and highly sensitive alternative to traditional methods, there is a growing interest in enhancing biosensor signals for efficient application. One such method of biosensor signal amplification is the use of nanostructured materials. In this work, we report the positive effect of tuning the properties of a substituted-kesterite nanomaterial, copper indium tin sulfide (CITS), using a chitosan capping agent, for efficient signal amplification of interferon gamma (IFN-γ) TB biomarker detection. This nanostructured chitosan-capped copper indium tin sulfide (χt-c-CITS) nanomaterials served as an excellent sensing platform, improving aptamer loading by 84.6 % and signal response by 73.9 %. High sensitivity to changes in IFN-γ concentration was obtained with the χt-c-CITS-based aptasensor between 100 fM to 1 pM dynamic linear range, and a detection limit of 23.2 fM. Excellent electrochemical stability was achieved with 94 % and 95.6 % signal stability recorded after 20 repeated chronocoulometry measurements and a 32-day storage period, respectively. The aptasensor likewise showed excellent specificity and selectivity to IFN-γ in the presence of interfering agents, with potential application in real biological samples
Graphitic carbon nitride (g-C3N4) in fuel cells: A comprehensive review of synthesis, functionalization, and multifaceted electrocatalytic roles
No full textThe commercialization of fuel cells hinges on developing low-cost, durable, platinum-group-metal (PGM)-free electrocatalysts. Graphitic carbon nitride (g-C3N4), an earth-abundant polymeric semiconductor, is a promising alternative due to its stability and tunable electronic structure. This review highlights the evolution of g-C3N4 from a material with inherent limitations, such as poor conductivity and low surface area, to a versatile platform for high-performance fuel cell components. We summarize key engineering strategies that overcome these drawbacks, including morphological control, electronic structure modulation via doping and defect engineering, and the formation of synergistic composites. Critically, this work provides a unique and holistic perspective by categorizing the distinct and synergistic electrocatalytic roles of engineered g- C3N4: (i) as a robust catalyst support superior to conventional carbons, (ii) as a potent metal-free catalyst for the oxygen reduction reaction (ORR), (iii) as an ideal scaffold for single-atom catalysts (SACs), and (iv) as a functional membrane additive. Despite significant progress, with performance rivaling platinum in alkaline media, major challenges persist. These include improving activity and stability in acidic environments (e.g. PEMFC) and developing scalable, cost-effective synthesis methods. This work consolidates the current state-of-the-art and outlines future research directions, including the use of advanced characterization and machine learning-assisted design, to realize the full potential of g-C3N4 for a sustainable energy future