Microbial levels on the food preparation areas of a typical district hospital in South Africa

Published ArticleThe role of hospital surfaces (including surfaces in food preparation areas) in the transmission of hospital-acquired infections (HAI) has been long recognized; however, evidence regarding this critical information is not well documented. This study was conducted at a typical district hospital in the Free State Province of South Africa. Using swabs, surface samples were collected from nine kitchen areas, quantified and identified using the MALDI-TOF MS and API. Fungal counts (1 x 103 to 2.3 x 105 cfu.cm-2) were higher compared to bacterial counts (1.5 x 103 to 1.1 x 105 cfu.cm-2). A total of 25 bacterial species and 14 fungal species were identified from hospital kitchen surfaces using the MALDI-TOF MS. Candida was the most common fungal genus identified represented by 11 species while Bacillus was the most common bacterial genus isolated represented by 7 species. The presence of species from the genera Acinetobacter, Enterobacter, Pseudomonas and Candida amongst others on kitchen surfaces could have serious consequences as they have been implicated in various studies as probable causes of hospital acquired infections. The study highlights the need to ensure proper cleaning of working surfaces in the kitchen as well as stringent surveillance and monitoring to ensure the minimal contamination of food products prepared for patients

South African Mine Effluents: Heavy Metal Pollution and Impact on the Ecosystem

Published ArticleSouth Africa embarks on extensive mining activities, which consequently produce enormous quantities of toxic HMs1 that pollute the surroundings; subjecting the ecosystem to dangers of infections and diseases. Prevalence of HMs in different environmental media and their impact depend on the physical and chemical states of the metal, which tends to persist in their localities because they cannot be biologically or chemically degraded as with organic substances. Mine fugitive dust clouds the environment; in most cases causing irrevocable damage to the biota, with harmful metals usually transferred from water bodies to the food chain via assimilation, bioaccumulation and biomethylation processes

Characterisation of selected volatile organic compounds in Rwandan indigenous beer ‘Urwagwa’ by dynamic headspace gas chromatography-mass spectrometry

The volatile organic compound profile of alcoholic beverages consists of a wide range of compounds, comprising of acids, alcohols, esters, aldehydes, and other trace level aroma compounds. These compounds play an important role as they provide relative information on the product quality and enhance product acceptability. In this study, two brands of commercially available traditional banana beer samples were collected from a local market in Kigali, Rwanda; and were analyzed for volatile organic compounds. Dynamic headspace, using gas chromatography-mass spectrometry (DHS/GCMS), was used to identify volatile compounds at three different temperatures. Fifty volatile compounds, inclusive of 14 acids, 14 alcohols, and 22 esters were identified and quantified in the two brands of indigenous banana beer samples. Only 12 volatile components (three alcohols, three acids and six esters) were common in all banana beer samples. Among all the identified compounds, ethanol and acetate were the dominant compounds in all beer samples. Ethanol levels were found to be 8.7 and 18.1% (v/v) for brand A and B, respectively using gas chromatography (GC). The two major toxic compounds, methyl alcohol and ethyl carbamate/urethane, were detected in lower concentration levels compared to other identified compounds, thus suggesting negligible risk.Keywords: Indigenous banana beer, volatile compounds, dynamic headspace, gas chromatography-mass spectrometry (GC-MS), ‘Urgwagwa’African Journal of Biotechnology Vol. 12(20), pp. 2990-299

Genome-wide identification, annotation and characterization of novel thermostable cytochrome P450 monooxygenases from the thermophilic biomass-degrading fungi Thielavia terrestris and Myceliophthora thermophila

Published ArticleCytochrome P450 monooxygenases (P450s) are ubiquitous heme-thiolate proteins that have potential biotechnological application. Thermostable-P450s that can withstand hostile industrial conditions, such as high temperatures, extremes of pH and organic solvents, are needed for biotechnological usage. Here, for the first time, we report a large number of thermostable-P450s from two thermophilic biomass-degrading fungi, Myceliophthora thermophila and Thielavia terrestris. Genome-wide P450 analysis revealed the presence of 79 and 70 P450s (P450ome) in T. terrestris and M. thermophila. Authentic P450s containing both the P450 signature domains (EXXRand CXG) were classified as follows: T. terrestris (50 families and 56 subfamilies) and M. thermophila (49 families and 53 subfamilies). Bioinformatics analysis of P450omes suggested the presence of a large number of thermostable-P450s. Based on aliphatic index cut-off ([90), 14 and 11 P450s were determined to be thermostable in T. terrestris and M. thermophila. Among the thermostable P450s, six P450s from T. terrestris and three from M. thermophila had a melting temperature (Tm) of [65 C, suggesting their hyperthermal tolerance. Analysis of the instability index of two ascomycete P450omes revealed the presence of 12 and 19 in vitro stable P450s in T. terrestris and M. thermophila. Overall, six P450s from T. terrestris and four from M. thermophila showed both thermal tolerance and in vitro stability. Thermophilic ascomycetes P450s are of potential interest from a structural, mechanistic and biotechnological point of view, as five P450s showed higher thermal tolerance and five showed higher in vitro stability compared to the wellcharacterized thermostable-P450s CYP175A1 (bacteria) and CYP119 (archaea)

Functional Evolution of Free Quantum Fields

We consider the problem of evolving a quantum field between any two (in general, curved) Cauchy surfaces. Classically, this dynamical evolution is represented by a canonical transformation on the phase space for the field theory. We show that this canonical transformation cannot, in general, be unitarily implemented on the Fock space for free quantum fields on flat spacetimes of dimension greater than 2. We do this by considering time evolution of a free Klein-Gordon field on a flat spacetime (with toroidal Cauchy surfaces) starting from a flat initial surface and ending on a generic final surface. The associated Bogolubov transformation is computed; it does not correspond to a unitary transformation on the Fock space. This means that functional evolution of the quantum state as originally envisioned by Tomonaga, Schwinger, and Dirac is not a viable concept. Nevertheless, we demonstrate that functional evolution of the quantum state can be satisfactorily described using the formalism of algebraic quantum field theory. We discuss possible implications of our results for canonical quantum gravity.Comment: 21 pages, RevTeX, minor improvements in exposition, to appear in Classical and Quantum Gravit

Defining the microbial transcriptional response to colitis through integrated host and microbiome profiling

The gut microbiome is significantly altered in inflammatory bowel diseases, but the basis of these changes is not well understood. We have combined metagenomic and metatranscriptomic profiling of the gut microbiome to assess modifications to both bacterial community structure and transcriptional activity in a mouse model of colitis. By using transcriptomic analysis of colonic tissue and luminal RNA derived from the host, we have also characterised how host transcription relates to the microbial transcriptional response in inflammation. In colitis, increased abundance and transcription of diverse microbial gene families involved in responses to nutrient deprivation, antimicrobial peptide production and oxidative stress support an adaptation of multiple commensal genera to withstand a diverse set of environmental stressors in the inflammatory environment. These data are supported by a transcriptional signature of activated macrophages and granulocytes in the gut lumen during colitis, a signature that includes the transcription of the key antimicrobial genes S100a8 and S100a9 (calprotectin). Genes involved in microbial resistance to oxidative stress, including Dps/ferritin, Fe-dependent peroxidase and glutathione S-transferase were identified as changing to a greater extent at the level of transcription than would be predicted by DNA abundance changes, implicating a role for increased oxygen tension and/or host-derived reactive oxygen species in driving transcriptional changes in commensal microbes

Quantizing the damped harmonic oscillator

We consider the Fermi quantization of the classical damped harmonic oscillator (dho). In past work on the subject, authors double the phase space of the dho in order to close the system at each moment in time. For an infinite-dimensional phase space, this method requires one to construct a representation of the CAR algebra for each time. We show that unitary dilation of the contraction semigroup governing the dynamics of the system is a logical extension of the doubling procedure, and it allows one to avoid the mathematical difficulties encountered with the previous method.Comment: 4 pages, no figure

Evaluating the Influences of Natural Resources and Ageing People on CO2 Emissions in G-11 Nations: Application of CS-ARDL Approach

Globalization as well as the ratio of ageing people in the group of 11 (G-11) countries has seen a rapid increase in recent years. Therefore, this study aims to provide effective policy recommendations for sustainable development goals 13, 8, and 7, for the G-11 countries. This work estimates the impact of natural resources and the ageing population on the emission of carbon dioxide (CO2) in G-11 countries using panel data from 1990–2020. For empirical results, second-generation methods were applied. The Westerlund co-integration test that assesses co-integration confirms the firm association among the parameters, and the values of coefficient of the cross-sectional autoregressive distributed lag (CS-ARDL) approach show that a 1% increase in the ageing population will lower the emissions of CO2 by 13.41% among G-11 countries. Moreover, the findings show that there exists an environmental Kuznets curve (EKC) among natural resources, globalization, economic growth, ageing people, and the emission of CO2. Based on the findings, this work presents some important policy implications for achieving sustainable growth in the G-11 countries. These countries need to lower the amount of energy obtained from fossil fuels to improve air quality. © 2022 by the authors. Licensee MDPI, Basel, Switzerland