Microbial Assessment Research Articles

A novel approach for microbial activity assessment in bioleaching. Towards to a standardised fast starting up protocol

Biohydrometallurgy is a proven industrial method for extracting base metals from sulfidic ores with low-grade content and as a pre-treatment of Au ores. The lack of study of biological aspects related with microbial activity assessment makes it difficult to control and monitor these processes; and the multitude of experimental procedures described in the literature hinders cross-study comparisons among researchers. Experimental tools that allow a quick and reliable quantitative assessment of the iron oxidising capacity of the cells during the bioleaching process are needed. This work proposes monitoring microbial activity through a simple and reliable method based on the offline measurement of the Oxygen Uptake Rate (OUR). The methodology allows to quantify the microbial activity evolution of a growing culture under no-limiting conditions. By this methodology, the maximum potential bioleaching rate of the culture at any time is determined, assessing the occurrence of a biological or chemical limitation. The results obtained reveals that whether due to Fe2+ or O2 depletion, substrate availability significantly limits microbial activity. This aspect is key to assess a culture suitability for bioleaching bioreactor inoculation, preventing long lag phases. Furthermore, the methodology allows for quick disturbances correction, avoiding process shutdowns and enhances technological reliability of continuous bioleaching.

Accumulation of microbial hazards and assessment of food hygiene associated with broiler chicken processing at open air food markets in Maputo, Mozambique

Accumulation of microbial hazards and assessment of food hygiene associated with broiler chicken processing at open air food markets in Maputo, Mozambique

Physio-chemical and microbial assessment of the source of drinking water and the prevailing waterborne diseases in Gwagwalada Municipal Area Council of Abuja, Nigeria

Water contamination poses a serious threat to the wellbeing of people globally. In Nigeria, there have been increasing cases of waterborne diseases owing to water contamination, thus becoming public health concerns. This study investigated the physio-chemical properties, microbial loads of borehole water samples from Gwagwalada area council of Abuja and its prevailing waterborne diseases. Borehole water samples were collected from five wards of the council area (Gwagwalada central (YZTM), University of Abuja Staff quarters (YZTMB), Dobi (SBWTM), Tunga Maje (TMCBW), and Ikwa (YZBTM) in triplicate and analyzed for physiochemical properties (temperature, conductivity, pH, turbidity, salinity, total dissolved solids (TDS), and heavy metals) and microbial contamination using standard methods. Surveillance to determine the prevalence of waterborne diseases was also carried out in the health facilities of the area council. All samples showed variable concentrations in most of the physiochemical parameters and were within the recommended thresholds except for conductivity (596.01 ± 0.00 μS/cm) and chlorine (254.18 ± 0.00 mg/l) in TMCBW sample and total dissolved solids in TMCBW (948.01 ± 14.14 mg/l) and YZTM (GC) (1871.00 ± 55.15 mg/l) water samples. E. coli, Enterobacter spp., Shigella spp., Lactobacillus spp., Pseudomonas ssp., and Proteus ssp. were bacteria isolates of the samples. Principal component analysis of interrelationship showed a strong positive relationship between some physio-chemical parameters and sampling locations. Also, there was heavy burden of gastrointestinal (waterborne) diseases. The study concludes that the borehole samples from the area were contaminated and maybe unfit for consumption. Thus, call for interventions that provide safer portable water or treat existing water sources towards achieving SDG No. 6 and to prevent outbreaks of waterborne diseases that could emanate from the consumption of unsafe water.

Utilizing the IFS Standard for the Implementation of Sustainable Development Practices in Juice Production

The aim of this study was to identify the most common threats and non-compliances occurring during the production of unpasteurized fruit juices in relation to the requirements of the IFS standard. Additionally, this study aimed to demonstrate how the IFS standard supports the introduction of sustainable practices in the production of fruit juices. The research material was data from internal audits conducted in three plants producing unpasteurized fruit juices and final product microbial assessment and swabs from the production environment taken from the three plants. These plants are located in western Poland. Based on the assessment carried out, it was found that most non-compliances were identified in the areas covered by prerequisite programs, but the final product and production environment met product and production safety requirements. It was also stated that the corrective actions proposed and approved by the auditors correct the existing non-compliance without the aspect of continuous improvement. The research and audits carried out as part of this work allowed us to conclude that international standards, such as the IFS, are an excellent tool for introducing the principles of a sustainable approach to production plants.

Effects of indigenous microorganisms on the CO2 adsorption capacity of coal

The adsorption capacity of coal is a crucial criterion for CO2 sequestration in deep unminable coal seams. Previous studies have documented how indigenous microorganisms interact with supercritical carbon dioxide (ScCO2) in coal. But how these interactions affect the adsorption capacity were rarely investigated. In this study, we treated bituminous coal samples with ScCO2-H2O and ScCO2-H2O-microorganism interactions in high-pressure reactors for 120 days at 35 °C and 10 MPa, respectively. After the treatments, we characterized both coal pore types and structures. The comparisons between two different post-treatments indicate that no significant change in coal pore types but notable alterations in pore structures are observed. Specifically, the treated coal with microorganisms exhibits a significant increase in micropore specific surface area (SSA) and surface roughness than the one without them. However, changes in meso/macropore structures and overall pore complexity of the coal sample treated with microorganisms were less pronounced than in coal sample treated with ScCO2-H2O alone. FTIR spectra analysis indicated that the absorption peak intensity of oxygen-containing groups and aliphatic functional groups in the sample treated with microorganisms decreased much more significantly than the sample treated without microorganisms. The CO2 adsorption capacity slightly increased in all treated samples at equilibrium pressures below 2.5 MPa. Above this pressure, the coal sample treated with microorganisms maintained a higher CO2 adsorption capacity, while the sample treated without microorganisms exhibited lower CO2 adsorption capacity compared to untreated coal sample. The increased SSA and the reduced oxygen-containing functional groups of coal after the treatment exerted antagonistic effects on CO2 adsorption. These findings suggest that indigenous microorganisms in coal seams affect CO2 adsorption through antagonistic effects, necessitating site-specific microbial assessments.

Eco-Friendly Innovation: Crafting Bio-Environmental Rice Husk Board for Sustainable Living

Background: The growing focus on environmental sustainability and safety has heightened the demand for eco-friendly household materials. This study explores the development of a bio-based board using rice husk (RH), assessing its properties and potential for diverse applications. Methods: The board was formulated using 30 g RH powder, 2 ml glycerol, 4 g agar, 3 g calcium propionate, and 100 ml water. The study involved visual and textural evaluation, physical property testing, and microbial growth assessment. Practical utility was examined through the fabrication of various objects including boxes and candle bases, and material adaptability was tested by varying RH concentrations and additives. Results: The RH boards, with equal proportions of RH and RH powder, exhibited light weight and good physical characteristics. Microbial growth was limited to 39% under conditions of 37 °C and 95% humidity. The boards were moldable, with a smooth, easily colorable surface post-sanding, demonstrating shape stability and flame retardancy under prolonged heat exposure. Furthermore, the material demonstrates good compatibility; varying RH ratios, colorants, and preservatives yield different appearance effects and characteristics. Conclusions: This study successfully developed a sustainable, safe, and versatile RH board, showcasing significant commercial potential and suitability as an innovative eco-friendly material.

Seasonal assessment of surface water and sediments pollution in Rachiine River, Northern Lebanon, using multivariate statistical analysis

Urbanization has caused severe negative impacts on intra-urban river water worldwide. In this study, the WHO drinking water standards (2024) were used as reference to assess the physicochemical properties, heavy metals (HMs) content and microbial load in water and sediment samples collected from 25 locations along Rachiine River, located in Northern Lebanon, during wet and dry periods. Multivariate statistical analysis was applied to evaluate the seasonal variations in water and sediment quality, and determine the pollution sources. The microbial load assessment indicated high pollution levels by Escherichia coli, fecal enterococci, total coliform and fecal coliform, which generally increased as the river progressed downstream. Cluster analysis (CA) provided three major clusters in the study region, representing the northern, central, and southern sectors of the river. Principal components analysis (PCA) of water samples generated four principal components (PCs) accounting for 64.3, 11.4, 7.6 and 4.1 % of the total variance, whereas PCA of sediment samples explained 59.1, 16.9 and 11.1 % of the data set variance. These PCs revealed that the quality of water and sediments is significantly impacted by point and diffuse sources, including geological and anthropogenic factors. These findings call for urgent management strategies to limit future deterioration of the aquatic bodies.

A preclinical model for osteoarticular fracture fragment preservation for delayed re-implantation

BackgroundOpen articular fractures often include contaminated, devascularized osteoarticular fragments that are critical for joint reconstruction. Definitive treatment is often delayed such that decontamination and preservation of critical fragments for joint reconstruction is highly desirable. To validate decontamination and preservation protocols for safe and effective preservation of osteoarticular fragments for re-implantation, a preclinical animal model for inducing type 3 open articular fractures with contaminated, devascularized osteoarticular fragments was developed and validated. Materials and methodsWith IACUC approval, purpose-bred hounds (n = 5) were humanely euthanized. Immediately following euthanasia, a penetrating captive bolt pistol with 1.25 grain cartridge centered on the cranial aspect of each distal humerus was discharged to create open fractures in 3 dogs (6 elbows). In 2 dogs, matched osteoarticular tissues from non-injured elbows (controls) were retrieved for comparison. Distal humerus, proximal radius, and proximal ulna osteoarticular fragments (n = 27) were immediately placed in Missouri Osteochondral Preservation System (MOPS) solution and stored at room temperature. Radiographic, chondrocyte viability, and quantitative microbial culture assessments were performed immediately (time-0) and at 7 and 14 days of storage. ResultsThis preclinical canine model reliably produced type 3 open distal humeral fractures characterized by devascularized and contaminated osteoarticular fracture fragments. All fragments produced extensive microbial growth through 14 days of storage. Without decontamination, viable chondrocyte density in the fragments decreased significantly within 7 days, likely attributable to the profound contamination. ConclusionThese data highlight the importance of developing a reliable method for point-of-care decontamination and preservation of osteoarticular fracture fragments for safe and effective reimplantation of articular fracture fragments for joint reconstruction.

Innovative probiotic yogurt: Leveraging green banana peel for enhanced quality, functionality, and sensory attributes

Yogurt, a popular dairy product renowned for its nutritional benefits and probiotic content, serves as a functional food with potential health-promoting properties. The objective of this study was to investigate whether incorporating green banana peel polyphenol extract (GBPPE) into yogurt formulations enhances the viability and functionality of probiotics while also potentially improving the overall quality and health-promoting properties of the yogurts. GBPPE was extracted and added to the yogurt formulation at 0.0 %, 0.5 %, 1 %, and 2 %. Various physico-chemical properties of GBPPE as well as a range of physical, biochemical, sensory, and microbial assessments of formulated yogurts were carried out. Compared to the control, yogurt containing GBPPE improves functional characteristics by increasing antioxidant activity while having no detrimental impact on physicochemical and organoleptic properties. In terms of antioxidant capabilities, all fortified yogurts showed significantly (p < 0.05) higher total phenolic, flavonoid contents and antioxidant activities than the control yogurt. The addition of GBPPE also affected (p < 0.05) pH, titratable acidity, viscosity, water-binding capacity, syneresis, and total soluble solids, while no significant differences in the color parameters were detected in both control and all fortified yogurts with reduced brightness (L∗) and increased redness (a∗) of the product. The initial viable counts of all yogurt samples were almost similar, and the maximum and minimum viability loss of probiotics were observed in control and 2 % GBPPE fortified samples, respectively. Sensory assessment revealed that yogurt with 0.5 % banana peel extract outperformed all other treatments except the control. These findings support the sustainable use of GBPPE to create probiotic yogurt with improved physicochemical, microbiological, and sensory qualities.

Antimicrobial Effects of Orthodontic Molar Tube Coated with ZnO Nanoparticles Using Electrophoretic Deposition Method: A Randomized Clinical Trial.

This study aimed to evaluate the antimicrobial effect of coated orthodontic molar tubes (COMT) with zinc oxide nanoparticles (ZnO NPs) using an electrophoretic deposition method (EPD) and to evaluate the orthodontic molar tubes (OMT) bond failure rate. Seventy-two orthodontic molar tubes (OMTs) for second molars were divided into two groups 36 each; one group coated with ZnO NPs and the other control negative uncoated. The OMT was coated using the EPD method with ZnO NPs in a concentration of 10g/l. The OMTs were randomly allocated using a split-mouth, cross-quadrant design. After 2weeks of appliance placement, swabs were taken from the surface of the OMTs for microbial assessment against Streptococcus mutans, Lactobacillus acidophilus, and total bacterial counts; additionally, plaque and gingival indices were assessed. The patient was followed for 3months to evaluate the bond failure rate. The COMT showed a statistically significant reduction in total bacterial accounts, S. mutans, and L. acidophilus compared to UOMT (P < 0.001). Furthermore, the plaque and gingival indices near COMT were significantly less than that of UOMT. The bond failure rate was not significant between the COMT and UOMT. The COMT with ZnO NPs has potent antibacterial activity against the tested pathogens with a reduction in the amount of plaque accumulation. The use of the EPD method was feasible without adverse effects on theorthodontic molar tubes bond failure rate.

Hyaluronic acid-solid lipid nano transporter serum preparation for enhancing topical tretinoin delivery: skin safety study and visual assessment of skin.

The use of nanosized particles is becoming more popular for the topical treatment of skin conditions. In this research work, we created and investigated the effects of solid lipid nanoparticles (SLN) containing hyaluronic acid and tretinoin. Solvent emulsification diffusion method was used to prepare the SLN formulation and characterized for their physicochemical properties. Fourier transform infrared spectroscopy was used to confirm that hyaluronic acid and tretinoin were incorporated in the SLN. Furthermore, X-ray diffractogram, thermal analysis including DSC and TGA and in vitro dissolution, permeation tests were also performed along with microbial assessment. Clinical studies in human were performed to evaluate the effect of the SLN on skin wrinkles. The SLN was 750 ± 31.29nm in size, with a zeta potential of 13.07 ± 0.75mV and a narrow polydispersity index of 0.24 ± 0.12. The entrapment efficiency of tretinoin was found to be 90.07 4.79%. Clinical studies in healthy human volunteers demonstrated that 90% of the tested individuals had improved skin conditions (reduction in wrinkles), by at least one grade after 4weeks of treatment. Regarding the development on SLN, it was found that the internal phase concentration did not considerably affect the physicochemical and microbiological properties. Therefore, Hyaluronic acid has potential for the development of SLN applicable to cosmetic formulations, especially for skin. These findings show that the developed SLN have potential for use as cosmetics in the future.

Investigations of microbial adaptation to singular, binary, and fully formulated quaternary ammonium compounds.

The study was conducted to inform risk assessments concerning microbial exposure to quaternary ammonium biocides (QUATs) by investigating their effects on 10 microbial strains of hygiene relevance. Biocides were divided into three categories: simple aqueous solutions, biocide mixtures, and formulated biocides. Organisms were grown in the presence of biocides for 10 generations and then subsequently for another 10 generations in biocide-free media. Control organisms were passaged 20 times in biocide-free media. Strains were then assessed for biocide and antibiotic susceptibility, changes in growth dynamics, and single nucleotide polymorphisms (SNPs). Biocide mixtures demonstrated greater antimicrobial potency than singular and formulated biocides. Susceptibility changes of under twofold were observed for all biocides tested. Susceptibility decreased significantly for organisms passaged with singular biocides (1.29- to 4.35-fold) and biocide mixtures (1.4- to 1.5-fold), but not for formulated biocides (1.3- to 1.84-fold) compared to controls. Antibiotic susceptibility both increased and decreased in passaged organisms, with heightened susceptibility occurring more frequently in the singular biocide group. Changes in susceptibility and growth dynamics were similar in the passaged and unexposed controls for fitness measures of adapted bacteria; there were no significant differences between biocide groups, but significantly lower generation and doubling times in organisms exposed to singular biocides. Similar frequencies in SNPs occurred for the three biocide groups and unexposed controls. While some adaptations occurred, particularly with singular biocides, the impact on antibiotic resistance and genomic mutations was limited. These findings suggest that the use of formulated QUATs may pose a comparatively lower risk for antimicrobial resistance.IMPORTANCEBiocides are used globally to control microbial growth and effective assessment of the risks and benefits of their use is therefore a high priority. Much of the data used to assess risk has been based on sub-lethal exposure of bacteria to singular biocides in simple aqueous solutions. This work builds on limited prior realism-based studies to demonstrate enhanced potency in biocidal mixtures; the mitigation of resistance selection by formulations and inconsistent cross-resistance effects with both increases and decreases in susceptibility for a wide range of antibiotics. These data can be used to better inform risk assessments of biocide deployment.

Poly-Ether-Ether-Ketone versus dead-soft coaxial bonded retainers: a randomized clinical trial. Part 2: periodontal health and microbial biofilm assessment.

Retainers have the potential to detrimentally impact periodontal health and contribute to tooth decay. To investigate periodontal health and bacterial biofilm related to Poly-Ether-Ether-Ketone (PEEK) fixed retainers as compared to Dead-soft coaxial fixed retainer (DSC). A two-arm parallel groups single-centre randomized clinical trial. The trial included patients whose orthodontic treatment was completed and required retainers. Participants were randomly assigned into two retainer groups: PEEK retainers, prepared by computer-aided design and manufacturing into 0.8mm wire form, and DSC retainers. The objectives included assessing periodontal health through plaque accumulation index (PI), bleeding on probing (BOP), periodontal pocket depth (PPD), gingival index (GI), calculus index (CI), and alveolar bone height (ABH) assessment. Biofilm assessment involved bacteriological screening of aerobic, facultative anaerobic, mutans streptococci, and lactobacilli. The periodontal indices and microbiological screening as well as were assessed at the debonding stage (T0), 1-month (T1), 3-month (T3), and 6-month (T6) after the commencement of the trial, except for the ABH, which was recorded using periapical radiograph at T0 and T6. Single blinding of participants in addition to the bacteriological specialist. Initially, the trial enrolled 46 participants, aged between 12 and 28 years, and were randomly assigned to two groups, with 23 participants in each group. Subsequently, one participant withdrew from the trial, resulting in a total of 45 participants whose data were analysed. Assessment of the periodontal indices, excluding the CI (P = .480), revealed statistically but not clinically significant differences between groups after 6-month of retention (P = .016 of PI, P = .020 of BOP, P = .05 of PPD, and P = .01 of GI). There was slight plaque accumulation, normal PPD (approximately 1mm), healthy to mild gingivitis with a GI of less than 1 and BOP was around 10%. Concerning the ABH, there was a noticeable reduction in its score after 6 months, particularly in the PEEK group, although the difference was not statistically significant (P = .102). Furthermore, the bacteriological viable count did not show any significant difference between the groups during the recall visits. There have been no reported negative consequences. Blinding the assessor of periodontal indices was not feasible due to the nature of the intervention. The trial follow-up duration was limited. Both the PEEK and DSC retainers have comparable impacts on periodontal health and bacterial accumulation and composition during the retention period. NCT05557136.

Drivers of microbial carbon biomass variability in two oceanic regions of the Gulf of Mexico

The microbial plankton community is an integral part of the pelagic ecosystem. It hosts essential functional groups that play a vital role in organic carbon production, release, uptake, and degradation within open-ocean ecosystems. Given its significance, carbon biomass estimates are urgently needed, especially in oligotrophic regions, to provide and enhance our knowledge of biogenic carbon pools. They also aid in validating biogeochemical models that characterize the functioning of these extensive marine ecosystems within the global carbon cycle. This study addresses the temporal variability of microbial community biomass in two oceanic zones: the west-central (Perdido) and southern (Coatzacoalcos) areas of the Gulf of Mexico. During three seasonally contrasting periods (nortes, rainy, and dry seasons), seawater samples were collected from the euphotic zone in both regions to estimate the carbon biomass of different pico- (<2–3 µm), nano-, and microplankton groups (>3–200 µm). Carbon biomass assessments for the microbial groups were based on their abundance and carbon conversion factors. Overall, we found a significant contribution of pico-prokaryotic components (heterotrophic bacteria, Prochloroccocus, and Synechoccocus) to the total microbial carbon stock of the euphotic zone (84–89 % global estimates). The finding suggests these microorganisms are key functional groups that drive carbon production and fate in the Gulf of Mexico ecosystem. Pico-cyanobacteria, especially Prochloroccocus, were the dominant primary producers (68–82 % total autotrophic carbon), mainly in the upper layer of the oligotrophic euphotic zone. This vertical pattern implies that the deep chlorophyll-a maximum (DCM) depth level was unrelated to a net increase in phytoplankton biomass in the three study periods. The distribution of microbial carbon biomass exhibited striking differences associated with winter mixing (the nortes season), high river discharge accompanied by cross-shelf transport (the rainy season), and the dynamics of mesoscale structures. Ecological aspects, such as the habitat preference of the organisms and the seasonal complementary development of mixotrophic and heterotrophic grazers and their prey, were also essential drivers in regulating the microbial carbon pool of both oceanic regions. The microbial carbon assessments conducted in this study contribute to identifying and quantifying key planktonic functional groups involved in the biogeochemical carbon cycle in the Gulf of Mexico open-ocean ecosystem.

Sample Preservation Solution Increases Nucleic Acid Yield and Environmental RNA Quality in Sediments Across an Estuarine Salinity Gradient

ABSTRACTEnvironmental nucleic acid‐based assessments are powerful tools for understanding microbial ecology, and environmental degradation in aquatic environments. This approach is particularly useful in guiding restoration in estuaries, some of the most degraded ecosystems in the world. The recent popularity of this approach has been accompanied by a parallel increase in the diversity of applied methods. A range of best practice methods exist across the field that can be employed and are selected based on environmental considerations such as physicochemical gradients, maximizing yield, and quality of nucleic acids sampled across sites within a study area. A consistent approach to intra‐study nucleic acid sampling also ensures accurate comparison between those sites. This study evaluates environmental nucleic acid (eNA) sampling methods across salinity gradients in aquatic ecosystems, focusing on the impact of preservation techniques on environmental DNA (eDNA) yield and environmental RNA (eRNA) yield and quality. Fieldwork was conducted at three sites within the Coorong estuary system in South Australia, representing low salinity, marine, and hypersaline conditions. Snap freezing and LifeGuard preservation solution treatments were applied in situ to compare their effects on nucleic acid yields and eRNA integrity. Snap freezing enhanced eDNA yield in low salinity sediments but negatively impacted eRNA integrity in marine and hypersaline conditions. Conversely, treatment with preservation solution consistently improved both eDNA and eRNA recovery across all salinity levels, which makes this approach a good candidate for preserving eNA molecules across environmental gradients. The study underscores the necessity of tailoring sample preservation methods to specific environmental conditions for accurate eNA‐based microbial community assessments in coastal ecosystems. These findings contribute to the development of robust eNA sampling protocols for benthic communities under varying salinity conditions.

Microbial and Physicochemical Assessment of Road-Side Roasted Plantain Sold in Isoko North Local Government Area, Nigeria

Microbial and Physicochemical Assessment of Road-Side Roasted Plantain Sold in Isoko North Local Government Area, Nigeria

Effect of Storage Temperatures on the Quality and Microbial Safety of Fish-Based Sausage Analogs: A Physical and Microbial Assessment

Effect of Storage Temperatures on the Quality and Microbial Safety of Fish-Based Sausage Analogs: A Physical and Microbial Assessment

The metabolic network response and tolerance mechanism of Thalassia hemprichii under high sulfide based on widely targeted metabolome and transcriptome

Costal eutrophication leads to increased sulfide levels in sediments, which has been identified as a major cause of the global decline in seagrass beds. The seagrass Thalassia hemprichii, a dominant tropical species in the Indo-Pacific, is facing a potential threat from sulfide, which can be easily reduced from sulfate in porewater under the influence of global climate change and eutrophication. However, its metabolic response and tolerance mechanisms to high sulfide remain unclear. Thus, the current study investigated the physiological responses and programmed metabolic networks of T. hemprichii through a three-week mesocosm experiment, integrating physiology, stable isotope, widely targeted metabolomics, transcriptomics, and microbial diversity assessments. High sulfide reduced the sediment microbial diversity, while increased sediment sulfate reduced bacterial abundance and δ34S. The exposure to sulfide enhanced root δ34S while decreased leaf δ34S in T. hemprichii. High sulfide was shown to inhibit photosynthesis via damaging PSII, which further reduced ATP production. In response, abundant up-regulated differentially expressed genes in energy metabolism, especially in oxidative phosphorylation, were activated to compensate high energy requirement. High sulfide also promoted autophagy by overexpressing the genes related to phagocytosis and phagolysosome. Meanwhile, metabolomic profiling revealed that the contents of many primary metabolites, such as carbohydrates and amino acids, were reduced in both leaves and roots, likely to provide more energy and synthesize stress-responsive secondary metabolites. Genes related to nitrate reduction and transportation were up-regulated to promote N uptake for sulfide detoxification. High sulfide levels specifically enhanced thiamine in roots, while increased jasmonic acid and flavonoid levels in leaves. The distinct differences in metabolism between roots and leaves might be related to sulfide levels and the growth-defense trade-off. Collectively, our work highlights the specific mechanisms underlying the response and tolerance of T. hemprichii to high sulfide, providing new insights into seagrass strategies for resisting sulfide.

Microbial assessment of the ecological linkage between a red tide of Karenia brevis and bottom water anoxia off the coast of Fort Myers and Sanibel Island, Florida

Coastal ecosystem management necessitates a comprehensive understanding of the physical, chemical, and biological components and their interplay with socio-economic activities. Red tides of Karenia brevis reoccur almost annually on the West Florida Shelf and cause significant human and environmental health problems that often result in negative economic impacts. It is crucial that we understand the processes and dynamics of both phytoplankton and microbial communities as conditions necessary for the formation of hypoxia and anoxia in the coastal ecosystem. With the aim of identifying key microbial communities responsible for anoxia, we investigated the 2017–2018 Karenia bloom. Various water quality parameters, phytoplankton, and microbial community compositions were studied at eight sites on the West Florida Shelf. K. brevis densities were highest at the site of the plume of the Caloosahatchee River. At the site with the highest K. brevis abundance (6.3 ×106 cells/L), dissolved oxygen (DO) was supersaturated (303 %) at the surface, and the chlorophyll a concentration was 118 µg/L. The highest bacterial cell count (9.0 ×106 cells/mL) and the lowest bacterial diversity were also observed at this site. The bacterial community determined by high-throughput amplicon sequencing at this bloom site was unique and dominated by Bacteroidetes, which occupied 65 % of the relative abundance of the microbial community. The bottom water was generally hypoxic (mean ± SD: 0.98 ± 1.13 mg/L), with select stations having DO as low as 0.06 mg/L (anoxic). The anoxic bottom water harbored unique microbial taxa that were associated with the low oxygen conditions. Significant negative correlations were found between DO and the relative abundance of Deltaproteobacteria, Firmicutes, Spirochaetes, and unclassified Proteobacteria. Our investigation lays the groundwork for subsequent studies delving into the responses of phytoplankton and microbial communities to disturbances caused by Karenia blooms, as well as future strategies for mitigation and ecosystem restoration.

Microbial Diversity Assessment in Soil from Dumping Sites: Isolation, DNA Extraction and Electrophoretic Analysis

This study aims to investigate the microbial diversity present in soil samples collected from various dumping sites, which are known for their complex and heterogeneous waste environments. The primary objective is to isolate and characterize the microbial communities inhabiting these soils, providing insights into their composition and potential ecological roles. Soil samples were collected by digging 5 cm deep at multiple dumping locations to ensure a representative sampling of the microbial populations. The collected soil samples underwent a serial dilution process, extending up to 10^-9 and 10^-10 dilutions, to facilitate the isolation of individual microbial colonies. These diluted samples were then inoculated onto Standard Potato Dextrose Agar (PDA) media, a nutrient-rich medium conducive to microbial growth. Following an incubation period, distinct bacterial colonies were observed and isolated for further analysis. DNA was extracted from the isolated bacterial colonies using a standard DNA extraction protocol. The quality and purity of the extracted DNA were assessed through gel electrophoresis, a technique that separates DNA fragments based on their size. Remarkably, the electrophoretic analysis revealed clear and distinct DNA bands along with RNA bands, indicating successful extraction of high-quality microbial DNA. Notably, this was achieved without the use of proteinase treatment, which is typically employed to remove protein contaminants from DNA samples. The results of this study underscore the robustness of the methodologies employed in isolating and characterizing microbial DNA from soil samples collected at dumping sites. The presence of distinct DNA and RNA bands highlights the effectiveness of the DNA extraction process, even in the absence of proteinase treatment. These findings provide valuable insights into the microbial diversity within dumping site soils, suggesting a rich and varied microbial community that may play significant roles in soil health and waste decomposition.