Diversity Of Microorganisms Research Articles

External Thermal Insulation Composite Systems—Past and Future in a Sustainable Urban Environment

In recent decades, the sustainable development of the planet has been negatively affected by a number of factors, including the construction industry. The construction industry includes, among other things, the highly topical energy reconstruction of existing prefabricated residential housing, which is implemented to improve their condition from a thermal engineering and energy perspective. Composite materials, known as external thermal insulation composite systems (ETICSs), have come to the fore, bringing a number of undeniable benefits to society. After more than 20 years of experience, it turns out that in addition to the benefits, ETICSs also bring new research challenges to the discussion, which are related to the issue of the biocorrosion of the external envelope of ETICSs, and also to the issue of the indoor microclimate. Based on the literature review and case studies, we aim to show that ecologically friendly building materials require a multidisciplinary approach. At the same time, we want to contribute to the discussion of whether the diversity of microorganisms on ETICS composites is a potential source of health risks and whether the transport of microorganisms to the indoor environment can be ruled out through natural ventilation from the outdoor environment to the interior.

Effect of Rice–Carp Coculture on Phytoplankton and Microzooplankton Community Composition in Paddy Water during Different Rice Growth Stages

Integrated rice–fish farming, an agricultural practice that combines cultivating rice and breeding fish in the same field, has attracted widespread attention. However, there is limited research on how the rice–carp coculture impacts the community structure of phytoplankton and microzooplankton in paddy water. This study employed eDNA metabarcoding sequencing to analyze the composition of phytoplankton and microzooplankton in a rice monoculture system (RM) and a rice–carp coculture system (RF). Following annotation, we identified 9 phyla, 89 families, 275 genera, and 249 species of phytoplankton, along with 20 phyla (or subphyla and classes), 85 families, 222 genera, and 179 species of microzooplankton. The alpha diversity indices revealed significantly higher richness, diversity, and evenness in the RF group compared to the RM group during grain-filling stage. Principal coordinates analysis (PCoA) demonstrated notable differences in the phytoplankton and microzooplankton compositions between the two groups across various rice growth stages. Composition analysis showed that rice–carp coculture increased the relative abundance of dominant phytoplankton phyla such as Bacillariophyta, Chrysophyta, and Euglenophyta while decreasing that of Cryptophyta. In microzooplankton, the coculture resulted in an increased abundance of Intramacronucleata (subphylum) and a decrease in Conoidasida (class). In conclusion, the rice–carp coculture enhances the diversity of plankton, particularly during the grain-filling stage, and simultaneously alters the composition and abundance of dominant plankton species in the paddy water. These findings enhance understanding of the broader impacts of integrated rice–carp farming on agricultural ecosystems, emphasizing alterations in the diversity and composition of aquatic microorganisms

Community structure of soil microorganisms and endophytes of honeysuckle at different ecological niche specificities

BackgroundThe plant microbiome is one of the key determinants of healthy plant growth. However, the complexity of microbial diversity in plant microenvironments in different regions, especially the relationship between subsurface and aboveground microorganisms, is not fully understood. The present study investigated the diversity of soil microorganisms in different regions and the diversity of microorganisms within different ecological niches, and compared soil microorganisms and endophytic microorganisms.Methods16 S and ITS sequencing was used to sequence the soil and endophytes microbiome of honeysuckle. Alpha diversity analysis and principal component analysis (PCoA) were used to study the soil and endophyte microbial communities, and the function of endophyte bacteria and fungi was predicted based on the PICRUST2 process and FUNGuild.ResultsIn total, there were 382 common bacterial genera and 139 common fungal genera in the soil of different producing areas of honeysuckle. There were 398 common bacterial genera and 157 common fungal genera in rhizosphere soil. More beneficial bacteria were enriched in rhizosphere soil. Endophytic bacteria were classified into 34 phyla and 770 genera. Endophytic fungi were classified into 11 phyla and 581 genera, among which there were significant differences in the dominant genera of roots, stems, leaves, and flowers, as well as in community diversity and richness. Endophytic fungal functions were mainly dominated by genes related to saprophytes, functional genes that could fight microorganisms were also found in KEGG secondary functional genes.ConclusionMore beneficial bacteria were enriched in rhizosphere soil of honeysuckle, and the microbial network of the rhizosphere is more complex than that of the soil. Among the tissues of honeysuckle, the flowers have the richest diversity of endophytes. The endogenous dominant core bacteria in each part of honeysuckle plant have a high degree of overlap with the dominant bacteria in soil. Functional prediction suggested that some dominant core bacteria have antibacterial effects, providing a reference for further exploring the strains with antibacterial function of honeysuckle. Understanding the interaction between honeysuckle and microorganisms lays a foundation for the study of growth promotion, quality improvement, and disease and pests control of honeysuckle from the perspective of microorganisms.

Assembly and maintenance of phyllosphere microbial diversity during rubber tree leaf senescence

Phyllosphere microorganisms execute important ecological functions including supporting host plant growth, enhancing host resistance to abiotic stresses, and promoting plant diversity. How leaf developmental stages affect plant-microbiome interactions and phyllosphere microbial community assembly and diversity is poorly understood. In this study, we utilized amplicon sequencing of 16S rRNA and ITS genes to investigate the composition and diversity of microbial communities across different leaf developmental stages of rubber trees. Our findings reveal that endophytic microbial communities, particularly bacterial communities, are more influenced by leaf senescence than by epiphytic communities. The high abundance of metabolism genes in the endosphere of yellow leaves contributes to the degradation and nutrient relocation processes. Nutrient loss leads to a higher abundance of α-Proteobacteria (r-selected microorganisms) in the yellow leaf endosphere, thereby promoting stochastic community assembly. As leaves age, the proportion of microorganisms entering the inner layer of leaves increases, consequently enhancing the diversity of microorganisms in the inner layer of leaves. These results offer insights into the mechanisms governing community assembly and diversity of leaf bacteria and fungi, thereby advancing our understanding of the evolving functions of microbial communities during leaf senescence in general, and for an important tropical crop species in particular.

Influence of Varied Phosphorus Fertilizer Ratios on the Rhizosphere Soil Microbial Community in Idesia polycarpa Seedlings

Phosphorus (P) is crucial for tree growth and development, and it significantly influences the rhizosphere microbial community. However, the effects of phosphorus addition on the microbial communities in the rhizosphere soil of Idesia polycarpa remain understudied. In this study, two-year-old “Yuji” Idesia polycarpa seedlings were used to investigate the effects of phosphorus fertilization at four different levels of 0 g (control, CK), 0.92 g (low phosphorus, LP), 1.83 g (medium phosphorus, MP), and 2.75 g (high phosphorus, HP) per plant. The fertilizers were applied every 40 days over 120 days. MiSeq high-throughput sequencing of the 16S rRNA and ITS1 genes was employed to analyze the microbial community composition and diversity of bacteria and fungi in the rhizosphere soil under different phosphorus levels. The results showed that compared with CK treatment, the application of phosphorus fertilizer changed the physicochemical properties of the soil. The LP treatment significantly increased the soil pH, while the HP treatment group exhibited the highest soil-available phosphorus (AP) content. LP treatment significantly increased the number of microbial OTUs in the early and rapid growth stages and the richness and diversity of microbial communities. In addition, the bacterial community structure was significantly correlated with soil pH and AP, while the fungal community had no significant effect. The primary metabolic pathway function of bacteria in the rhizosphere soil of Idesia polycarpa seedlings is mainly metabolism, while fungi are mainly biosynthesis. Compared with CK treatment, 20 differential metabolic pathways were screened out in the bacterial community. Only two differential metabolic pathways were screened out in the fungal community by LP treatment at 120 days. In summary, applying low-level phosphate fertilizer is conducive to promoting the diversity of rhizosphere soil microorganisms. Therefore, potted planting of Idesia polycarpa seedlings is more suitable for applying low phosphorus levels.

A Global Comparison of Stream Diatom Beta Diversity on Islands Versus Continents Across Scales

ABSTRACTAimTo evaluate the patterns of stream diatom beta diversity in islands versus continents across scales, to relate community similarities with spatial and environmental distances and to investigate the role of island characteristics in shaping insular diatom beta diversity.LocationAfrica, America, Europe and the Pacific.Time PeriodPresent.Major Taxa StudiedStream diatoms.MethodsWe compared diatom beta diversity between islands and continents at large scales (within biogeographic regions) in two study regions (America and Europe) and at small scales (within islands/equivalent areas in continents) in three regions (Africa, America and Europe) partitioning beta diversity into turnover and nestedness components. We used a partial Mantel test and distance–decay curves to assess how diatom beta diversity on islands and continents is affected by spatial and environmental distances. Finally, using island data from all four regions, we evaluated the relationship between island beta diversity and island latitude, area, age and isolation using linear models.ResultsAt large scales, mean dissimilarities were higher on islands than in continents in Europe but lower in America. At smaller scales, the differences varied mostly depending on island isolation. Beta diversity was mainly caused by species turnover. Partial Mantel test and distance–decay curves revealed that spatial and environmental distances shaped diatom beta diversity at large, but not at small scales. Moreover, diatom beta diversity on islands was affected by island latitude, age and isolation, but not by island area.Main ConclusionsDiatom beta diversity on islands versus continents and its responses to spatial and environmental factors are scale and region dependent. Incomplete colonisation, evolutionary processes and environmental filtering likely contribute to insular beta diversity, which further varies with island latitude, age and isolation. This study sheds new light on beta diversity of microorganisms on islands and suggests that beta diversity should be explicitly considered in island biogeographical research.

Implementing high-throughput insect barcoding in microbiome studies: impact of non-destructive DNA extraction on microbiome reconstruction.

Symbiotic relationships with diverse microorganisms are crucial for many aspects of insect biology. However, while our understanding of insect taxonomic diversity and the distribution of insect species in natural communities is limited, we know much less about their microbiota. In the era of rapid biodiversity declines, as researchers increasingly turn towards DNA-based monitoring, developing and broadly implementing approaches for high-throughput and cost-effective characterization of both insect and insect-associated microbial diversity is essential. We need to verify whether approaches such as high-throughput barcoding, a powerful tool for identifying wild insects, would permit subsequent microbiota reconstruction in these specimens. High-throughput barcoding ("megabarcoding") methods often rely on non-destructive approaches for obtaining template DNA for PCR amplification by leaching DNA out of insect specimens using alkaline buffers such as HotSHOT. This study investigated the impact of HotSHOT on microbial abundance estimates and the reconstructed bacterial community profiles. We addressed this question by comparing quantitative 16S rRNA amplicon sequencing data for HotSHOT-treated or untreated specimens of 16 insect species representing six orders and selected based on the expectation of limited variation among individuals. We find that in 13 species, the treatment significantly reduced microbial abundance estimates, corresponding to an estimated 15-fold decrease in amplifiable 16S rRNA template on average. On the other hand, HotSHOT pre-treatment had a limited effect on microbial community composition. The reconstructed presence of abundant bacteria with known significant effects was not affected. On the other hand, we observed changes in the presence of low-abundance microbes, those close to the reliable detection threshold. Alpha and beta diversity analyses showed compositional differences in only a few species. Our results indicate that HotSHOT pre-treated specimens remain suitable for microbial community composition reconstruction, even if abundance may be hard to estimate. These results indicate that we can cost-effectively combine barcoding with the study of microbiota across wild insect communities. Thus, the voucher specimens obtained using megabarcoding studies targeted at characterizing insect communities can be used for microbiome characterizations. This can substantially aid in speeding up the accumulation of knowledge on the microbiomes of abundant and hyperdiverse insect species.

Transitioning ecosystems: how will permafrost cryophiles respond to a changing climate?

Permafrost harbours a diversity of cryophilic microorganisms that can be metabolically active at sub-zero temperatures and likely play a role in global carbon cycling. This forum article explores possible impacts of permafrost warming on cold-adapted microbiota, highlights underexplored areas of research, and suggests future short and long-term research foci.

Diversified crop rotations improve soil microbial communities and functions in a six-year field experiment

Diversified crop rotations can help mitigate the negative impacts of increased agricultural intensity on the sustainability of agroecosystems. However, the impact of crop rotation diversity on the complexity of soil microbial association networks and ecological functions is still not well understood. In this study, a 6-year field experiment was conducted to evaluate how six different crop rotations change the composition and network complexity of soil microbial communities, as well as their related ecological functions. Microbial traits were measured in six crop rotations with different crop diversity index (CDI) during 2016–2022, including winter wheat–summer maize (CDI 1, WM) as the control, sweet potato→winter wheat–summer maize (CDI 1.5, SpWM), peanut→winter wheat–summer maize (CDI 1.5, PWM), soybean→winter wheat–summer maize (CDI 1.5, SWM), spring maize→winter wheat–summer maize (CDI 1.5, SmWM), and ryegrass–sweet sorghum→winter wheat–summer maize (CDI 2, RSWM). The study findings indicated that diversified crop rotations significantly increased ASV richness of both bacterial and fungal communities after 6-year treatments, and the β-diversity profiles of bacterial and fungal communities significantly distinguished at the year of 2022 from 2016. The relative abundance of Acidobacteria and Chloroflexi was significantly enriched in SpWM rotation at 2022, while Basidiomycota significantly declined in five diversified rotations compared to WM. Diversified crop rotations at 2022 increased the complexity and density of bacterial and fungal networks than 2016. SpWM and PWM rotations had the highest functional groups involved in chemoheterotrophy and saprotroph, respectively. Structural equation modelling (SEM) also revealed that diversified crop rotations increased soil nutrients through improving the composition of bacterial communities and the augmented intricacy of the interconnections within both bacterial and fungal communities. This research underscores the importance of preserving the diversity and ecological functions of soil microorganisms in the nutrient-recycling processes for efficient agricultural practices.

Genomic profiling of Antarctic geothermal microbiomes using long-read, Hi-C, and single-cell techniques

Geothermal features in Antarctica provide favorable conditions for diverse microorganisms, yet their genomic diversity remains poorly understood. Here, we present an integrated dataset comprising PacBio HiFi and Hi-C metagenomic sequencing, along with single-cell amplified genomes (SAGs) from two high-altitude geothermal sites, Mount Melbourne and Mount Rittmann, in Antarctica. The long-read HiFi sequencing, coupled with Hi-C, enhances the understanding of microbiome diversity and functionality in this unique ecosystem by providing more complete and accurate genomic information. SAGs complement this by recovering rare microbial taxa and offering a strain-resolved perspective. This dataset aims to deepen our understanding of microbial evolution and ecology in Antarctic geothermal environments, and facilitate cross-comparison with other geothermal environments globally.

Pangenomic landscapes shape performances of a synthetic genetic circuit across Stutzerimonas species.

Engineering identical genetic circuits into different species typically results in large differences in performance due to the unique cellular environmental context of each host, a phenomenon known as the "chassis-effect" or "context-dependency". A better understanding of how genomic and physiological contexts underpin the chassis-effect will improve biodesign strategies across diverse microorganisms. Here, we combined a pangenomic-based gene expression analysis with quantitative measurements of performance from an engineered genetic inverter device to uncover how genome structure and function relate to the observed chassis-effect across six closely related Stutzerimonas hosts. Our results reveal that genome architecture underpins divergent responses between our chosen non-model bacterial hosts to the engineered device. Specifically, differential expression of the core genome, gene clusters shared between all hosts, was found to be the main source of significant concordance to the observed differential genetic device performance, whereas specialty genes from respective accessory genomes were not significant. A data-driven investigation revealed that genes involved in denitrification and components of trans-membrane transporter proteins were among the most differentially expressed gene clusters between hosts in response to the genetic device. Our results show that the chassis-effect can be traced along differences among the most conserved genome-encoded functions and that these differences create a unique biodesign space among closely related species.IMPORTANCEContemporary synthetic biology endeavors often default to a handful of model organisms to host their engineered systems. Model organisms such as Escherichia coli serve as attractive hosts due to their tractability but do not necessarily provide the ideal environment to optimize performance. As more novel microbes are domesticated for use as biotechnology platforms, synthetic biologists are urged to explore the chassis-design space to optimize their systems and deliver on the promises of synthetic biology. The consequences of the chassis-effect will therefore only become more relevant as the field of biodesign grows. In our work, we demonstrate that the performance of a genetic device is highly dependent on the host environment it operates within, promoting the notion that the chassis can be considered a design variable to tune circuit function. Importantly, our results unveil that the chassis-effect can be traced along similarities in genome architecture, specifically the shared core genome. Our study advocates for the exploration of the chassis-design space and is a step forward to empowering synthetic biologists with knowledge for more efficient exploration of the chassis-design space to enable the next generation of broad-host-range synthetic biology.

Probiotic Bacillus subtilis QST713 improved growth performance and enhanced the intestinal health of yellow-feather broilers challenged with coccidia and Clostridium perfringens

In this study, we investigated the effects of dietary supplementation with Bacillus subtilis (QST713) on the performance and intestinal health of yellow feather broilers under Coccidia and Clostridium perfringens (CP) challenge or CP alone. One-day-old yellow-feathered broiler roosters (n = 600) were randomly assigned to 5 groups (6 replicates with 20 roosters per replicate): the Con blank group, the CIC.p group (d24 Coccidia+d28-30 of CP challenge), the CIC.p + BS group (CIC.p +100 mg/kg B. subtilis), the C.p group (d 28-34 of CP challenge), and the C.p +BS group (C.p +100 mg/kg B. subtilis). The experiment lasted 80 d. The birds were evaluated for parameters such as average daily gain (ADG), average daily feed intake (ADFI), feed efficiency (F/G), intestinal lesion score, villus histomorphometry, intestinal tight junctions, inflammatory factors, and cecal microorganisms. The results revealed that 1) C.p. increased the F/G of broilers from 22 to 42 d (P < 0.05), whereas CIC.p. significantly decreased the 42 d and 80 d body weights (BW) and 22-42 d and 1-80 d ADG (P < 0.05) and significantly increased the 22 to 42 d and 1 to 80 d F/G (P < 0.05). The number of intestinal lesions significantly increased at 35 d and 42 d (P < 0.05). CIC.p significantly decreased the jejunum and ileum villus height (VH) and the ileum villus height/crypt depth (P < 0.05) at 35 d. The challenge significantly upregulated the expression of Claudin-1 and IL-4 mRNAs in the jejunum at 35 d and significantly downregulated the expression of IL-10 mRNA in the ileum at 35 d (P < 0.05); the number of unique OTUs in the challenge group decreased significantly after challenge treatment, and the relative abundances of Romboutsia at 35 d and Cladomyces and Lactobacillus at 42 d decreased significantly (P < 0.05). 2) Compared with the challenge groups, the addition of BS decreased the F/G of broilers from 22 to 42 d. Compared with the CIC group, the addition of BS significantly increased the F/G of broilers from 22 to 42 d. Compared with that in the CIC.p group, the addition of BS significantly increased the VH in the jejunum and ileum at 35 d (P < 0.05). Compared with the challenge groups, the BS groups presented significantly lower mRNA expression levels of Claudin-1 (P < 0.05) in the jejunum at 35 d. The Shannon and Chao indices suggested that BS increased the alpha diversity of cecum microorganisms in broilers. Dietary supplementation with B. subtilis can alleviate the damage to intestinal morphology and intestinal barrier function, as well as the altered cecal flora structure in broilers caused by Coccidia and C. perfringens infections.

ZiBu PiYin recipe regulates central and peripheral Aβ metabolism and improves diabetes-associated cognitive decline in ZDF rats

Ethnopharmacological relevanceCognitive impairment caused by central neuropathy in type 2 diabetes mellitus (T2DM), namely diabetes-associated cognitive decline (DACD), is one of the common complications in patients with T2DM. Studies have shown that brain β-amyloid (Aβ) deposition is a typical pathological change in patients with DACD, and that there is a close relationship between intestinal microorganisms and cognitive impairment. However, the specific mechanism(s) of alteration in Aβ metabolism in DACD, and of the correlation between Aβ metabolism and intestinal microorganisms remain unknown. Aim of the studyRevealing the mechanism of ZBPYR regulating Aβ metabolism and providing theoretical basis for clinical evaluation and diagnosis of DACD. Materials and methodsWe characterized Aβ metabolism in the central and peripheral tissues of Zucker diabetic fatty (ZDF) rats with DACD, and then explored the preventive and therapeutic effects of ZiBu PiYin Recipe (ZBPYR). Specifically, we assessed these animals for the formation, transport, and clearance of Aβ; the morphological structure of the blood-brain barrier (BBB); and the potential correlation between Aβ metabolism and intestinal microorganisms. ResultsZBPYR provided improvements in the structure of the BBB, attenuation of Aβ deposition in the central and peripheral tissues, and a delay in the development of DACD by improving the expression of Aβ production, transport, and clearance related protein in ZDF rats. In addition, ZBPYR improved the diversity and composition of intestinal microorganisms, decreased the abundance of Coprococcus, a bacterium closely related to Aβ production, and up regulate the abundance of Streptococcus, a bacterium closely related to Aβ clearance. ConclusionThe mechanism of ZBPYR ability to ameliorate DACD may be closely related to changes in the intestinal microbiome.

Arbuscular mycorrhizal fungal diversity in agricultural fields is explained by the historical proximity to natural habitats

Soil microbes are essential to maintain terrestrial ecosystem functionality. However, their diversity is threatened by land-use change, such as agricultural expansion and intensification. One important microbial group mediating the exchange of nutrients between plants and soil is arbuscular mycorrhizal (AM) fungi. The response of microorganism diversity to present and past habitat amount has been poorly studied. Here, we evaluate the potential role of current and historical natural habitat availability in explaining the diversity of AM fungi in arable fields. We conducted a spatially intensive sampling of three agricultural fields in Estonia. Soil AM fungal diversity was determined by soil DNA metabarcoding. We related AM fungal species richness, along with beta diversity components (turnover and nestedness), to abiotic conditions and natural habitat area availability at different spatial scales and time periods. Our findings showed a positive relationship between AM fungal richness and the amount of natural habitat area. Specifically, current AM fungal species richness was best explained by the amount of natural habitat from 130 years earlier, indicating a legacy effect of past land use on current soil biodiversity. The amount of past natural areas was negatively related to the beta diversity turnover component, indicating a replacement of AM fungal species in disturbed sites. While biodiversity-friendly farming is useful in promoting diverse soil biota, historical legacies can be persistent. Maintaining natural habitats around agricultural fields can further promote soil AM fungal diversity for future generations.

Characterization of Silica Sand-Based Pervious Bricks and Their Performance under Stormwater Treatment

The acceleration of urbanization has disrupted natural water cycles, resulting in increased impervious urban surfaces and non-point source pollution from stormwater runoff. Addressing urban stormwater recharge has become crucial. This study introduces a novel silica sand-based permeable filtration material, investigating its surface characteristics, pore structure, permeability, and pollutant interception capabilities. The results demonstrate that hydrophilic binder coating modification of the permeable surface sand aggregate, combined with hydrophilic inorganic additives, having a porous structure with an average pore size of less than 50 μm and a porosity between 15% and 35%, significantly enhances surface hydrophilicity, achieving a permeation rate of up to 6.8 mL/(min·cm²). Moreover, it shows exceptional filtration and anti-clogging properties, achieving over 98% suspended solids interception and strong resistance to fouling. Dynamic biofilm formation experiments using simulated rain and domestic wastewater explore biofilm morphology and function on silica sand filtration well surfaces. Mature biofilms sustain COD removal efficiency exceeding 70%, with levels consistently below 50 mg/L, NH4+ decreasing to 2 mg N/L, and total nitrogen maintained below 10 mg N/L. The system features anoxic, anoxic, and aerobic zones, fostering synergistic organic matter and nitrogen removal by diverse microorganisms, enhancing pollutant mitigation. Silica sand-based permeable filtration material effectively mitigates urban stormwater runoff pollutants—suspended solids, organic matter, and nitrogen—offering an innovative solution for sponge city development and rainwater resource management.

Metagenomics Insight into Veterinary and Zoonotic Pathogens Identified in Urban Wetlands of Los Lagos, Chile.

Wetlands are ecosystems that are essential to ecological balance and biodiversity; nevertheless, human activity is a constant threat to them. Excess nutrients are caused by intensive livestock and agricultural operations, pollution, and population growth, which in turn leads to uncontrolled microbiological development. This impairment in water quality can constitute a risk to animal, human, and environmental health. To thoroughly characterize the microbial communities, shotgun metagenomics was used to characterize the taxonomic and functional pattern of microorganisms that inhabit urban wetlands in the Los Lagos Region of Chile. The main objective was to identify microorganisms of veterinary relevance, assess their potential antibiotic resistance, and characterize the main virulence mechanism. As expected, a high diversity of microorganisms was identified, including bacteria described as animal or human pathogens, such as Pasteurella multocida, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Also, a diverse repertory of antimicrobial-resistant genes (ARGs) was detected in metagenomic assembled sequences and inside the sequence of mobile genetic elements, genes that confer mainly resistance to beta-lactams, consistent with the families of antibiotics most used in Chile. In addition, a diverse collection of virulence mechanisms was also identified. Given the significance of the relationship between environmental, animal, and human health-a concept known as One Health-there is a need to establish molecular surveillance programs that monitor the environmental biohazard elements using molecular tools. This work is the first report of the presence of these harmful biological elements in urban wetlands subjected to anthropogenic pressure, located in the south of Chile.

Microbial growth on temporary pacemaker leads post-TAVR: pathogen spectrum and clinical implications.

Transcatheter aortic valve replacement (TAVR) is an established treatment option for patients with symptomatic severe aortic stenosis across all stages of surgical risk. Rapid pacing during the procedure and the risk for the occurrence of conduction disturbances after TAVR requires the pre-interventional insertion of a temporary pacemaker (TP). However, this approach poses risks, including the risk of infection. For this reason, the following study aimed to investigate microbial growth on temporary pacemaker leads and its association with outcome post-TAVR and to identify associated pathogens and related risk factors. A prospective study was conducted including 344 patients undergoing TAVR at the Heart Centre Bonn. Of these, 97 patients did not require TP leads as they already had permanent pacemakers; this group was considered as comparison group. The TP leads of the remaining 247 patients were removed, sonicated, and cultured to investigate bacterial growth over a period of 14days. Finally, we compared patients without microbial growth (n = 184) and patients with microbial growth (n = 63). The primary endpoint of the study was 30-day all-cause mortality, secondary endpoints were periprocedural infections, the length of the postprocedural hospital stay, 30-day major vascular complications and the 30-day stroke rate. The majority of cases (74.5%) showed no bacterial growth. In the remaining cases (25.5%), diverse microorganisms were identified, mostly non-pathogenic bacteria. The statistical analysis revealed no significant differences between groups according to microbial growth in terms of 30-day mortality (p = 0.446), postprocedural hospital stay (p = 0.401), periprocedural infections (p = 0.434), 30-day major vascular complications (p = 1.0), and 30-day stroke rate (p = 1.0). Notably, the timing of sheath insertion was significantly associated with microbial growth; sheath placement more than 2days prior to the procedure was associated with a significantly higher risk of microbial growth (OR: 2.1; 95% CI 1.1-4.3) (p = 0.030). The presence of temporary leads does not significantly impact clinical outcomes, irrespective of bacterial growth on the lead. However, the timing and duration of sheath placement plays a crucial role in contamination incidence. Thus, temporary leads/sheaths should be placed shortly before the procedure and removed promptly to reduce the risk of contamination/infection.

Stabilization of Cd-contaminated Soil with Thiol-modified Biochar and Response of Soil Microorganisms

To explore the stabilization effect of livestock manure biochar on Cd-contaminated soil and its impact on the soil environment, a pot experiment was conducted to investigate the stabilization efficiency of cattle manure-biochar （BC） and thiol-modified biochar （SBC） on Cd in soil and their effect on the soil properties and microbial community. The structural equation model （SEM） was used to analyze the effect pathways of BC and SBC on the soil microbial community. The results showed that BC and SBC increased soil pH, available potassium, available phosphorus, and organic matter content but decreased soil available nitrogen content compared with those in CK. The stabilization efficiency of BC for Cd in soil was 14.97%, which was much lower than that of SBC （85.71%）. Moreover, SBC increased the abundance of dominant bacterial phyla in soil, with Proteobacteria, Bacteroidota, and Cyanobacteria increasing most significantly. SBC decreased the diversity of soil microorganisms, but the decrease was insignificant （P≥0.05） compared with that in CK and BC. SEM analysis indicated that the available phosphorus, available potassium, organic matter, and soil pH were the key factors influencing Cd availability in soil, whereas organic matter and Cd availability were the key factors affecting the soil microbial community. Overall, SBC could stabilize Cd effectively and increase the abundance of dominant bacteria and has great potential in the remediation of Cd-contaminated soil.

Halotolerant Endophytic Bacteria Priestia flexa 7BS3110 with Hg2+ Tolerance Isolated from Avicennia germinans in a Caribbean Mangrove from Colombia.

The mangrove ecosystems of the Department of Atlántico (Colombian Caribbean) are seriously threatened by problems of hypersalinization and contamination, especially by heavy metals from the Magdalena River. The mangrove plants have developed various mechanisms to adapt to these stressful conditions, as well as the associated microbial populations that favor their growth. In the present work, the tolerance and detoxification capacity to heavy metals, especially to mercury, of a halotolerant endophytic bacterium isolated from the species Avicennia germinans located in the Balboa Swamp in the Department of Atlántico was characterized. Diverse microorganisms were isolated from superficially sterilized A. germinans leaves. Tolerance to NaCl was evaluated for each of the obtained isolates, and the most resistant was selected to assess its tolerance to Pb2+, Cu2+, Hg2+, Cr3+, Co2+, Ni2+, Zn2+, and Cd2+, many of which have been detected in high concentrations in the area of study. According to the ANI and AAI percentages, the most halotolerant strain was identified as Priestia flexa, named P. flexa 7BS3110, which was able to tolerate up to 12.5% (w/v) NaCl and presented a minimum inhibitory concentrations (MICs) of 0.25 mM for Hg, 10 mM for Pb, and 15 mM for Cr3+. The annotation of the P. flexa 7BS3110 genome revealed the presence of protein sequences associated with exopolysaccharide (EPS) production, thiol biosynthesis, specific proteins for chrome efflux, non-specific proteins for lead efflux, and processes associated with sulfur and iron homeostasis. Scanning electron microscopy (SEM) analysis showed morphological cellular changes and the transmission electron microscopy (TEM) showed an electrodense extracellular layer when exposed to 0.25 mM Hg2+. Due to the high tolerance of P. flexa 7BS3110 to Hg2+ and NaCl, its ability to grow when exposed to both stressors was tested, and it was able to thrive in the presence of 5% (w/v) NaCl and 0.25 mM of Hg2+. In addition, it was able to remove 98% of Hg2+ from the medium when exposed to a concentration of 14 mg/L of this metalloid. P. flexa 7BS3110 has the potential to bioremediate Hg2+ halophilic contaminated ecosystems.

Developing the script "degenerate primer 111" to enhance the coverage of universal primers for the small subunit rRNA gene on target microorganisms.

Amplifying small subunit (SSU) rRNA genes with universal primers in assessing microbial populations diversity, but target microorganisms are sometimes omitted due to inadequate primer coverage. Adding degenerate bases to primers can help, but existing methods are complex and time-consuming. This study introduces a user-friendly tool called "Degenerate primer 111" for adding degenerate bases to existing universal primers. By aligning one universal primer with one uncovered target microorganism's SSU rRNA gene, this tool iteratively generates a new primer, maximizing coverage for the target microorganisms. The tool was used to modify eight pairs of universal primers (515F Parada-806R Apprill, S-D-Bact-0341-b-S-17/S-D-Bact-0785-a-A-21, OP_F114-KP_R013, 27F-1492R, 341F-806R, OP_F066-KP_R013, 515F Parada-926R Quince, 616*F-1132R), and generated 29 new universal primers with increased coverage of specific target microorganisms without increasing coverage of non-target microorganisms. To verify the effectiveness of the improved primers, one set of original and improved primers (BA-515F-806R and BA-515F-806R-M1) was used to amplify DNA from the same sample, and high-throughput sequencing of the amplicons confirmed that the improved primers detected more microbial species compared to the original primers. Future researchers can use this tool to develop more personalized primers to meet their diverse microorganism detection needs.