Comparing Methods for Detection and Quantification of Plasmodesmal Callose in Nicotiana benthamiana Leaves During Defense Responses.

Callose, a ß-(1,3)-d-glucan polymer, is essential for regulating intercellular trafficking via plasmodesmata (PD). Pathogens manipulate PD-localized proteins to enable intercellular trafficking by removing callose at PD or, conversely, by increasing callose accumulation at PD to limit intercellular trafficking during infection. Plant defense hormones like salicylic acid regulate PD-localized proteins to control PD and intercellular trafficking during immune defense responses such as systemic acquired resistance. Measuring callose deposition at PD in plants has therefore emerged as a popular parameter for assessing likely intercellular trafficking activity during plant immunity. Despite the popularity of this metric, there is no standard for how these measurements should be made. In this study, three commonly used methods for identifying and quantifying plasmodesmal callose by aniline blue staining were evaluated to determine the most effective in the Nicotiana benthamiana leaf model. The results reveal that the most reliable method used aniline blue staining and fluorescence microscopy to measure callose deposition in fixed tissue. Manual or semiautomated workflows for image analysis were also compared and found to produce similar results, although the semiautomated workflow produced a wider distribution of data points. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Occurrence, efficiency of treatment processes, source apportionment and human health risk assessment of pharmaceuticals and xenoestrogen compounds in tap water from some Ghanaian communities.

The occurrence of pharmaceuticals and xenoestrogen compounds (PXCs) in drinking water presents a dire human health risk challenge. The problem stems from the high anthropogenic pollution load on source water and the inefficiencies of the conventional water treatment plants in treating PXCs. This study assessed the PXCs levels and the consequential health risks of exposure to tap water from selected Ghanaian communities as well as that of raw water samples from the respective treatment plants. Thus the PXCs treatment efficiency of two drinking water treatment plants in the metropolises studied was also assessed. The study also conducted source apportionment of the PXCs in the tap water. Twenty six (26) tap and raw water samples from communities in the Cape Coast and Sekondi-Takoradi metropolises were extracted using SPE cartridges and analysed for PXCs using Ultra-fast-HPLC-UV instrument. Elevated levels of PXCs up to 24.79 and 22.02 µg/L were respectively recorded in raw and tap water samples from the metropolises. Consequently, elevated non-cancer health risk (HI > 1) to residential adults were found for tap water samples from Cape Coast metropolis and also for some samples from Sekondi-Takoradi metropolis. Again, elevated cumulative oral cancer risks >10-5 and dermal cancer risk up to 4 × 10-5 were recorded. The source apportionment revealed three significant sources of PXCs in tap water samples studied. The results revealed the inefficiency of the treatment plants in removing PXCs from the raw water during treatments. The situation thus requires urgent attention to ameliorate it, safeguarding public health. It is recommended that the conventional water treatment process employed be augmented with advanced treatment technologies to improve their efficacy in PXCs treatment.

Ecotoxicological and health risks associated with sediment-bound polycyclic aromatic hydrocarbons in peri-urban closed and open coastal lagoons.

Coastal urbanisation has ramifications for the sustainable development of developing nations. There are often unquantified ecological and health risks associated with urbanisation. Sixteen polycyclic aromatic hydrocarbons (PAHs) were analysed in surface sediment from three peri-urban coastal lagoons in southern Ghana. We found significant spatial variations of sediment PAHs. These variations were attributed to physiography of the lagoons and diverse anthropogenic activities surrounding them. Total PAHs ranged from 20.81 to 24,801.38 µg/kg (dry weight), underscoring a low to very high pollution level. Diagnostic ratios revealed both pyrogenic and petrogenic origins. Over 50 % of individual PAHs were of moderate ecological risk to benthic organisms, and cancer risk to humans was above the World Health Organisation's recommended safety limit (1 × 10-6). These ecological and health risks should be wake-up call for a more integrated urban planning approach to coastal urbanisation as coastal communities largely depend on natural ecosystems for food and livelihood opportunities.

Interaction of Acinetobacter sp. RIT 592 induces the production of broad-spectrum antibiotics in Exiguobacterium sp. RIT 594.

Antimicrobial resistance (AMR) is one of the most alarming global public health challenges of the 21st century. Over 3 million antimicrobial-resistant infections occur in the United States annually, with nearly 50,000 cases being fatal. Innovations in drug discovery methods and platforms are crucial to identify novel antibiotics to combat AMR. We present the isolation and characterization of potentially novel antibiotic lead compounds produced by the cross-feeding of two rhizosphere bacteria, Acinetobacter sp. RIT 592 and Exiguobacterium sp. RIT 594. We used solid-phase extraction (SPE) followed by liquid chromatography (LC) to enrich antibiotic extracts and subsequently mass spectrometry (MS) analysis of collected fractions for compound structure identification and characterization. The MS data were processed through the Global Natural Product Social Molecular Networking (GNPS) database. The supernatant from RIT 592 induced RIT 594 to produce a cocktail of antimicrobial compounds active against Gram-positive and negative bacteria. The GNPS analysis indicated compounds with known antimicrobial activity in the bioactive samples, including oligopeptides and their derivatives. This work emphasizes the utility of microbial community-based platforms to discover novel clinically relevant secondary metabolites. Future work includes further structural characterization and antibiotic activity evaluation of the individual compounds against pathogenic multidrug-resistant (MDR) bacteria.

Reliable detection and quantification of plasmodesmal callose in Nicotiana benthamiana leaves during defense responses.

Callose, a beta-(1,3)-D-glucan polymer, is essential for regulating intercellular trafficking via plasmodesmata (PD). Pathogens manipulate PD-localized proteins to enable intercellular trafficking by removing callose at PD, or conversely by increasing callose accumulation at PD to limit intercellular trafficking during infection. Plant defense hormones like salicylic acid regulate PD-localized proteins to control PD and intercellular trafficking during innate immune defense responses such as systemic acquired resistance. Measuring callose deposition at PD in plants has therefore emerged as a popular parameter for assessing the intercellular trafficking activity during plant immunity. Despite the popularity of this metric there is no standard for how these measurements should be made. In this study, three commonly used methods for identifying and quantifying PD callose by aniline blue staining were evaluated to determine the most effective in the Nicotiana benthamiana leaf model. The results reveal that the most reliable method used aniline blue staining and fluorescent microscopy to measure callose deposition in fixed tissue. Manual or semi-automated workflows for image analysis were also compared and found to produce similar results although the semi-automated workflow produced a wider distribution of data points.

Vehicular influence on atmospheric concentrations and source apportionment of polycyclic aromatic hydrocarbons in some major cities in three regions of Ghana using epiphytic lichens.

The present study employed epiphytic lichens as biomonitor and passive air sampler for the assessment of fifteen (15) atmospheric polycyclic aromatic hydrocarbons (PAHs) in some major cities in three regions of Ghana. A total of 36 composite lichen samples were collected and analysed using Gas Chromatography - Tandem Mass Spectrometry (GC-MS-MS). The total PAH recorded ranged between 1909.9 ng/kg (A36) and 250,091.4 ng/kg (W15). Due to the inherent deficiencies in using a single source apportionment tool, multiple source apportionment methods including diagnostic ratios, principal component analysis/absolute principal component scores (PCA-APCS) and APCS with automatic linear model (APCS-ALM) were used to ascertain the source of PAHs in the lichens. The diagnostic ratios revealed a mix source of wood/grass and petrol/petroleum fuel combustion, with the major source ascribing to wood/grass combustion. The source apportionment confirmatory statistical test conducted with the PCA-APCS and APCS-ALM, were in good agreement with the diagnostic ratio. Both PCA-APCS and APCS-ALM suggested two significant sources (p < 0.0), with wood/grass combustion as the major (contributing 77.8%) and mix petroleum related sources being the other with 22.2% contribution of PAHs to the receptor sites. The study found PCA-APCS and especially APCS-ALM to be an effective statistical tool for PAH source apportionment in passive air samplers. To our knowledge, this is the first use of lichens for PAH monitoring in the country. Therefore, this study could serve as an inexpensive and real time bio-monitoring tool for air quality assessment in the African sub-region and the world at large.

Occurrence, ecological risk assessment and source apportionment of pharmaceuticals, steroid hormones and xenoestrogens in the Ghanaian aquatic environments.

Elevated levels of pharmaceuticals, steroid hormones and xenoestrogens (PSHXEs) in the aquatic environment pose a serious threat to the ecological balance. The endocrine disrupting PSHXEs in aquatic systems are linked to several adverse effects like reproductive health impairment, feminization, high mortality rate, decreased biodiversity etc. This study, therefore, sought to investigate the occurrence and the ecological risks posed by some selected PSHXEs and also conduct source apportionment of the PSHXEs in the Ghanaian aquatic environments. A total of 48 samples comprising 24 sediments and water each were taken from six waterbodies in Ghana. The samples were extracted using SPE cartridges for water and QuEChERS-dSPE for sediments. The analyses were done using Shimadzu Prominence UFLC 20A series. Ecological risk assessments were also conducted with the aid of USEPA T.E.S.T., whereas source apportionments were conducted using the APCS-MLR receptor model. Elevated mean total levels of PSHXEs ranging between 12,187 and 52,117 ng/L and 2,022-6,047 ng/g for water and sediment samples respectively were found. The risk quotients (RQ > 1) suggested a high risk posed by PSHXEs in water to organisms at the three trophic levels and also to benthic organisms in sediments of the Ghanaian aquatic environments for a short-term period. The APCS-MLR receptor model suggested three statistically significant sources (p < 0.05) designated by signature PSHXEs as domestic (major), mix hospital and industrial and agricultural waste sources. The source apportionment suggested increased use of steroid estrogens and anabolic drugs among the Ghana populace.

Evolutionary paths to macrolide resistance in a Neisseria commensal converge on ribosomal genes through short sequence duplications.

Neisseria commensals are an indisputable source of resistance for their pathogenic relatives. However, the evolutionary paths commensal species take to reduced susceptibility in this genus have been relatively underexplored. Here, we leverage in vitro selection as a powerful screen to identify the genetic adaptations that produce azithromycin resistance (≥ 2 µg/mL) in the Neisseria commensal, N. elongata. Across multiple lineages (n = 7/16), we find mutations that reduce susceptibility to azithromycin converge on the locus encoding the 50S ribosomal L34 protein (rpmH) and the intergenic region proximal to the 30S ribosomal S3 protein (rpsC) through short tandem duplication events. Interestingly, one of the laboratory evolved mutations in rpmH is identical (7LKRTYQ12), and two nearly identical, to those recently reported to contribute to high-level azithromycin resistance in N. gonorrhoeae. Transformations into the ancestral N. elongata lineage confirmed the causality of both rpmH and rpsC mutations. Though most lineages inheriting duplications suffered in vitro fitness costs, one variant showed no growth defect, suggesting the possibility that it may be sustained in natural populations. Ultimately, studies like this will be critical for predicting commensal alleles that could rapidly disseminate into pathogen populations via allelic exchange across recombinogenic microbial genera.

ICT, energy consumption, financial development, and environmental degradation in South Africa.

The ICT, energy consumption, and carbon dioxide emissions (CO2) relationship is examined for South Africa spanning the period 1970-2019, while controlling for the effects of financial development. The findings of the study based on the Autoregressive Distributed Lag (ARDL), Dynamic Ordinary Least Squares (DOLS), and Fully Modified Ordinary Least Squares (FMOLS) estimators show that ICT and fossil fuel consumption contribute to carbon dioxide emissions, while renewable energy consumption and financial development reduce carbon dioxide emissions. Specifically, the results show that a 1% increase in ICT activities will increase CO2 emissions by 0.565% in the long-term, and any temporary shock to this long-run relationship is corrected by 93.20%. Further, there is no evidence of threshold effect of ICT on carbon emissions.

Health risk and source assessment of semi-volatile phenols, p-chloroaniline and plasticizers in plastic packaged (sachet) drinking water.

The presence of U.S. EPA priority organic contaminants in drinking water poses a dire health risk on consumers. Packaged drinking water such as plastic sachet drinking water has significantly gained market in both developed and developing countries, especially, its dominance in the Ghanaian market. The treatment process, packaging, and storage of the sachet drinking water contribute to the levels of genotoxic semi-volatile phenols, p-chloroaniline, and plasticizers contamination in the drinking water. The study thus sought to investigate the levels of semi-volatile phenols, p-chloroaniline, and plasticizer contaminants in sachet drinking water on the Ghanaian market and the associated health risk of exposure. The study also investigated the possible sources of the contaminants. A total of thirty (30) different brands of sachet water on the Ghanaian market were studied. The samples were extracted in replicates (n = 3) using Solid Phase Extraction (SPE) cartridges and further analysed with GC-MS (SIM mode). The source apportionment was conducted using absolute principal component analysis coupled with multiple, linear regression (APCA-MLR) and automatic linear regression (APCA-MALR) modelling. The mean total levels for the phenols, p-chloroaniline, and plasticizers were between 210.2 and 18,914.9, 11.2 and 18,871.0, and 21.2 and 69,834.1 ng/L respectively. The cumulative non-cancer risk (hazard quotient) and cancer risk upon exposure were computed to range between 2.1 × 10-3 and 1.2 and 1.5 × 10-7 and 1.3 × 10-4 respectively. About 37% of the samples had elevated cancer risk (>10-6) which may contribute to the existing incidence, cause for concern. The five sources found for the contaminants were apportioned as "environmental background (major)", "water treatment/disinfectant", "plastic/plasticizers", "storage and preservation", and "residual inter-conversion/degradation sources".

Exiguobacterium sp. is endowed with antibiotic properties against Gram positive and negative bacteria.

OBJECTIVE: In order to isolate and identify bacteria that produce potentially novel bactericidal/bacteriostatic compounds, two ponds on the campus of the Rochester Institute of Technology (RIT) were targeted as part of a bioprospecting effort. RESULTS: One of the unique isolates, RIT 452 was identified as Exiguobacterium sp. and subjected to whole-genome sequencing. The genome was assembled and in silico analysis was performed to predict the secondary metabolite gene clusters, which suggested the potential of Exiguobacterium RIT452 for producing antibiotic compounds. Extracts of spent growth media of RIT452 were active in disc diffusion assays performed against four reference strains, two Gram-negative (E. coli ATCC 25922 and P. aeruginosa ATCC 27853) and two Gram-positive (B. subtilis BGSC 168 and S. aureus ATCC 25923). Differential extraction and liquid chromatography was used to fractionate the extracts. Efforts to identify and elucidate the structure of the active compound(s) are still ongoing.

Fast, easy, cheap, robust and safe method of analysis of Sudan dyes in chilli pepper powder.

Illicit use of Sudan dyes, a group of harmful and carcinogenic azo dyes, in the food industry has taken a surge in various parts of the world, especially in Africa. Their use in food as additives pose a dire health risk to consumers and have been banned by various food regulatory bodies worldwide. To help increase surveillance, various methods have been proposed for their analysis in literature. This study also sought to experiment and propose an alternative method for quick, easy, cheap, robust and ecologically safe analysis of Sudan dyes in chilli pepper powder and similar matrices. The optimized method used a 6.0 mL mixture of acetone:acetonitrile (1:5 v/v) solvent in a modified QuEChERs method for extraction of Sudan dyes I-IV. The simultaneous analysis of the dyes were achieved on Shimadzu prominence UFLC 20AD coupled with SPD 20AX UV detector operated at dual wavelength of 500 and 480 nm. A total of twenty four (24) chilli pepper powder samples from eight different vendors on the Ghana market were analysed using the optimized method. Quantitation of analytes were done using the external standard calibration method with determination coefficient, R2 > 0.9999. The limit of detection (LOD) and limit of quantitation (LOQ) of the method were 0.02-0.04 mg/kg and 0.05-0.13 mg/kg respectively. A good recovery range between 85.3 - 121.2% were obtained for a spike level of 1.0 mg/kg in real samples. ANOVA analysis at 95% CL showed statistically no significant difference (p > 0.05) in the recoveries between samples and also between the individual compounds. The method experimented and proposed in this study is fast, easy, cheap, robust and ecologically safe, presenting an alternative method for routine analysis for increased rate of surveillance against the illicit use of Sudan dyes as food additives.

Levels and risk assessment of residual phthalates, polycyclic aromatic hydrocarbons and semi-volatile chlorinated organic compounds in toilet tissue papers.

The presence of phthalates, polycyclic aromatic hydrocarbons (PAHs) and semi-volatile chlorinated organic compounds (SVCOC) in toilet tissue papers may be detrimental to the health of consumers upon exposure. This study therefore, sought to investigate the levels of these toxicants in toilet tissue papers on the Ghanaian market and the associated risk of exposure. The study also sought to conduct source apportionments for analytes. A total of 32 composite toilet tissue samples from 8 different brands were analysed in replicates for PAHs, phthalates and SVCOCs. Analysis was conducted using Shimadzu GCMS QP 2020 with the MS operated in SIM mode. The results showed elevated levels of PAHs, phthalates, and appreciable levels of SVCOCs in the toilets tissue papers. The risk assessment conducted, showed an associated elevated cancer risk >10-4 for PAHs in all samples and DEHP in samples NN, BB and SF. The risk associated with the levels of carcinogenic SVCOCs were found to be > 10-5 but < 10-4.The hazard indices (HI) calculated for non-cancer effects, showed risk levels < 1.0 for phthalates in most toilet paper samples except for samples BB and SF. The HI recorded for chlorophenols were all <1. Cumulatively, these values suggested elevated cancer and non-cancer risk associated with the dermal use of the toilet tissue papers on the Ghanaian market. The PCA-MLR source apportionment suggested two significant sources of SVOCs in the toilet tissue papers. PAHs, phthalates and 2-chloronaphthalene were of one source (oil base source) whereas SVCOCs were of another source (bleaching process).

Perfluoroalkyl acids (PFAAs) in the Pra and Kakum River basins and associated tap water in Ghana.

Perfluoroalkyl acids (PFAAs) are persistent environmental pollutants that have been detected in various media including human serum. Due to concerns regarding their bioaccumulation and possible negative health effects, an understanding of routes of human exposure is necessary. PFAAs are recalcitrant in many water treatment processes, making drinking water a potential source of human exposure. This study presents the first report on contamination from PFAAs in river and drinking water in Ghana. The targeted PFAAs were perfluoroalkyl carboxylic acids (PFCAs) with C4-14 carbon chain and perfluoroalkane sulphonic acids (PFSAs) with C6, 8, 10. Five PFAA congeners - PFOA, PFOS, PFHxA, PFDA and PFPeA - were commonly detected in river and tap water. The mean concentrations of ∑PFAAs in the Kakum and Pra Rivers were 281 and 398ng/L, while tap water (supplied from the treatment of water from those rivers) contained concentrations of 197 and 200ng/L, respectively. PFOA and PFOS constituted about 99% of the ∑PFAAs. The risk quotient (RQ) attributed to drinking of tap water was estimated at 1.01 and 1.74 for PFOA and PFOS, respectively. For a country that has not produced these compounds, the RQs were unexpectedly high, raising concerns particularly about contamination from such emerging pollutants in local water sources. The study revealed limitations of local tap water treatment in getting rid of these emerging pollutants.

Distribution and Risk Assessment of Heavy Metals in Surface Water from Pristine Environments and Major Mining Areas in Ghana.

BACKGROUND: Ghana, like many countries in Africa, has a history of heavy metal pollution largely emanating from industrial effluent discharges and anthropogenic deposits on prevailing winds of pollutants from industrial activities. One of the biggest contributors to pollution in the Ghanaian environment is mineral mining. OBJECTIVES: The aim of this study was to determine the distribution and health risks of heavy metals in surface water from both pristine environments and major mining areas in Ghana. METHODS: A total of 32 composite samples were collected between September and October, 2014 to assess concentrations of heavy metals and pollution levels, as well as cancer and non-cancer risks to human health from exposure to heavy metals from four major mining regions and four rain forest reserves in the Western, Ashanti, Brong Ahafo and Eastern regions of Ghana. Samples were analyzed using atomic absorption spectrometry. RESULTS: The mean concentrations (mg/L) of heavy metals at the pristine sites ranged from 1.747 for iron (Fe) to 0.001 for mercury (Hg) and 0.453 for Fe to 0.002 for Hg at the mining sites. All the metals were found to be below World Health Organization (WHO) and United States Environmental Protection Agency (USEPA) recommended limits except for Hg, which was at the USEPA guideline limit. However, the concentrations of the metals from the mining sites were found to be slightly higher than those from the pristine sites. CONCLUSIONS: The concentrations of heavy metals in the Nyam, Subri, Bonsa and Birim Rivers from the mining sites and the Atiwa Range, Oda, Ankasa and Bosomkese Rivers from the pristine sites were found to be either below or within the USEPA and WHO's recommended limits for surface water. The health risk assessment values for the hazard quotient for ingestion of water (HQing), dermal contact (HQderm) and chronic daily intake (CDI) indicated no adverse effects as a result of ingestion or dermal contact from the rivers. However, arsenic (As) in both the pristine and mining sites and chromium (Cr) in the pristine sites pose a carcinogenic threat to the local residents.