Higher Relative Abundance Research Articles

Can we accurately predict the distribution of soil microorganism presence and relative abundance?

Soil microbes play a key role in shaping terrestrial ecosystems. It is therefore essential to understand what drives their distribution. While multivariate analyses have been used to characterise microbial communities and drivers of their spatial patterns, few studies have focused on predicting the distribution of amplicon sequence variants (ASVs). Here, we evaluate the potential of species distribution models (SDMs) to predict the presence–absence and relative abundance distribution of bacteria, archaea, fungi, and protist ASVs in the western Swiss Alps. Advanced automated selection of abiotic covariates was used to circumvent the lack of knowledge on the ecology of each ASV. Presence–absence SDMs could be fitted for most ASVs, yielding better predictions than null models. Relative abundance SDMs performed less well, with low fit and predictive power overall, but displayed a good capacity to differentiate between sites with high and low relative abundance of the modelled ASV. SDMs for bacteria and archaea displayed better predictive power than for fungi and protists, suggesting a closer link of the former with the abiotic covariates used. Microorganism distributions were mostly related to edaphic covariates. In particular, pH was the most selected covariate across models. The study shows the potential of using SDM frameworks to predict the distribution of ASVs obtained from topsoil DNA. It also highlights the need for further development of precise edaphic mapping and scenario modelling to enhances prediction of microorganism distributions in the future.

Seasonal fish larvae abundance and composition in seagrass habitats of coastal East Africa.

Seagrass habitats play a major role in fisheries productivity through nursery functions and feeding grounds for diverse fish species. However, little is known about the seasonal distribution of fish larvae at large spatial scales in coastal East Africa. We investigated drivers of the seasonal fish larvae abundance and composition in seagrass habitats in Kenya and Tanzania. We found a high diversity of fish larvae (54 families) inhabiting seagrass habitats that differed between sites and seasons. Fish larvae abundance were highest in Kenya, particularly during the northeast monsoon season. Overall, total larval abundances per site were low, reaching less than 190 individuals/100m3 in Kenya and less than 40 individuals/100m3 in Tanzania, likely related to the low productivity and strong hydrodynamic processes in this region. Our data suggests that most of the fish spawn year-round in these tropical waters as we did not find strong seasonal patterns. All sites had a high relative abundance of larvae from demersal spawning fishes, indicating that many fish species move to coastal sites for spawning. Primary productivity and dissolved oxygen, driven by hydrodynamics conditions are positively related to fish larvae productivity both in Kenya and Tanzania. These findings indicate that the occurrence of both resident and transient fish larvae in seagrass meadows is driven by strong hydrodynamic and tidal processes that transport fish larvae across adjacent habitats.

Lianas in tropical dry seasonal forests have a high hydraulic efficiency but not always a higher embolism resistance than lianas in rainforests.

Lianas have higher relative abundance and biomass in drier seasonal forests than in rainforests, but whether this difference is associated with their hydraulic strategies is unclear. Here, we investigate whether lianas of seasonally dry forests are safer and more efficient in water transport than rainforest lianas, explaining patterns of liana abundance. We measured hydraulic traits on five pairs of congeneric lianas of the tribe Bignonieae in two contrasting forest sites: the wet 'Dense Ombrophilous Forest' in Central Amazonia (~2 dry months) and the drier 'Semideciduous Seasonal Forest' in the inland Atlantic Forest (~6 dry months). We also gathered a broader database, including 197 trees and 58 liana species from different tropical forests, to compare hydraulic safety between habits and forest types. Bignonieae lianas from both forests had high and similar hydraulic efficiency but exhibited variability in resistance to embolism across forest types when phylogenetic relationships were taken into account. Three genera had higher hydraulic safety in the seasonal forest than in the rainforest, but species across both forests had similar positive hydraulic safety margins despite lower predawn water potential values of seasonal forest lianas. We did not find the safety-efficiency trade-off. Merging our results with previously published data revealed a high variability of resistance to embolism in both trees and lianas, independent of forest types. The high hydraulic efficiency of lianas detected here probably favours their rapid growth across tropical forests, but differences in hydraulic safety highlight that some species are highly vulnerable and may rely on other mechanisms to cope with drought. Future research on the lethal dehydration threshold and the connection between hydraulic resistance strategies and liana abundance could offer further insights into tropical forest dynamics under climatic threats.

Accumulation of typical persistent organic pollutants and heavy metals in bioretention facilities: Distribution, risk assessment, and microbial community impact

Bioretention facilities have proven highly effective in removing pollutants from runoff. However, there is a concerning paucity of research on the contamination characteristics and associated risks posed by refractory pollutants in these facilities following long-term operation. This research focuses on the distribution, sources, microbial community impact, and human health risks of pollutants in eight bioretention facilities that have been operational for 5–11 years. The results showed that the distribution of Cu, Zn, and Cd was closely related to anti-seepage measures. PAHs, PCBs, and OCPs primarily accumulated in the surface, with concentrations ranging from 7.42 to 20.34 mg/kg, 31.8–77.3 μg/kg, and 60.5–163.6 μg/kg, respectively. Their concentrations inversely correlate with the depth of the media. Although the majority of contaminants remained below their respective risk thresholds, their concentrations typically exceeded those of background soil values, indicating an enrichment phenomenon. Source analysis revealed that PAHs primarily originate from oil combustion, PCBs were linked to their related industrial products, DDTs had their main sources in technical DDx and residues from the use of dicofol, while HCHs were traced back to historical residues from agricultural activities. Microbial α-diversity (Chao 1 and Shannon) decreased by 8.3–23.4% and 0.8–4.4%, respectively, in different facilities after long-term operation. The most dominant microbial phylum in the facilities was Proteobacteria (all relative abundances >48%). The total relative abundance of dominant genera was 6.7–34.3% higher than the control site, and Pseudomonas, a typical POPs-heavy metal degrading bacterium, had the highest relative abundance (>1.2%). Cu, Zn, and Cd present no non-carcinogenic risks and have low potential ecological risks. However, the lifetime cancer risk for PAHs is 10−6 ∼10−4 in most facilities and is of concern. The cancer risk for PCBs is acceptable, while OCPs pose a low cancer risk only for children.

Why are triploid quaking aspen (Populus tremuloides) common?

Quaking aspen is a clonal tree species that has mixed ploidy, often with high relative abundance of both diploids and triploids but no haploids or tetraploids. Triploids typically have low fertility, leaving their occurrence apparently unlikely from an evolutionary perspective, unless they provide a "triploid bridge" to generating higher-fitness tetraploids-which are not observed in this species. This study focused on how triploidy can be maintained in quaking aspen. A computational model was used to simulate gamete production, sexual reproduction, asexual reproduction, parent survival, and offspring survival in a population. All parameters were assumed to be cytotype-dependent and environment-independent. Sampling methods were used to identify parameter combinations consistent with observed cytotype frequencies. Many processes and parameter values were sufficient to yield a moderate frequency of triploids, and very few were necessary. The most plausible route involved higher triploid survival at the parent or offspring stage and limited unreduced gamete production by either diploid or triploid parents. Triploid fertility was helpful but not necessary. The coexistence of diploids and triploids in quaking aspen is statistically likely and promoted by the existenceof commonly observed, long-lived triploid clones. However, other mechanisms not captured by the model related to environmental variation could also occur. Further empirical data or more complex but difficult-to-parameterize models are needed to gain further insight.

∆9-THC attenuates neurodegeneration seen in HIV-gp120 transgenic mice through downregulation of microglial cell activation, astrocytosis and by reversing gut dysbiosis

Abstract The GFAP-gp120Tg mice express soluble HIV-envelope protein gp120 in astrocytes and share many neuropathological features observed in the CNS of AIDS patients. Here, we investigated the effect of a cannabinoid, ∆9-THC, on gp120-mediated neuroinflammation and progression of neurodegeneration. We treated groups of GFAP-gp120Tg and C57/BL6 WT mice with ∆9-THC or the vehicle. Immunofluorescence imaging, flow cytometry, snRNA-sequencing, and shotgun sequencing were performed to understand the cellular and molecular level incidents. ∆9-THC reduced the neuroinflammation driven by gp120 by down-regulating the inflammatory chemokine receptors such as CCR5, CXCR4 on immune cells that directly access the CNS. Pronounced astrocytosis and microglial activation seen in Tg mice was significantly reduced following treatment with ∆9-THC. Neuroglial gene expression was also reversed after ∆9-THC treatment. Tg mice exhibited significant gut microbiota dysbiosis which was reversed by ∆9-THC. Members of the genera Alistipes, Prevotella, Plasmodium, Helicobacter, Desulfovibrio had higher relative abundance in Tg mice but reduced after ∆9-THC treatment. Taken together, this study demonstrates that ∆9-THC treatment significantly improves HIV-gp120-mediated pathogenesis of neurodegeneration, neuroinflammation, and helps to reshape gut microbiota (This work was supported in part by NIH grants R01ES030144, P01AT003961, P20GM103641, and R01AI123947, R01AI160896).

Abstract 2034: Gut Microbial Markers Associated With Clinical Features Of Peripheral Artery Disease

Introduction: The human gut microbiome and microbe-derived metabolites are known to be associated with cardiovascular disease. However, their associations with lower extremity peripheral artery disease (PAD) are not well understood. The goal of this study is to identify specific gut microbial markers associated with clinical features of PAD. Methods: Study participants aged ≥ 18 years with documented PAD and non-PAD controls were recruited from a single center and performed home fecal sample collection. Sample aliquots were stored at -80°C until DNA extraction and shotgun metagenome sequencing. Untargeted metabolite quantification was performed using nuclear magnetic resonance. Samples from participants on antibiotics were excluded. Raw paired end sequences were quality filtered using the KneadData pipeline followed by taxonomic annotation using Kraken2 against the UHGG database (v2.0.2) and species abundance estimation using Bracken. A species network was constructed with centered log-ratio transformed abundance data and statistical analyses were performed in R. Results: Among 115 study participants, 80 had PAD and 35 were non-PAD controls. Of those with PAD, 40 (50.0%) had chronic limb threatening ischemia (CLTI) and 39 (48.8%) had symptoms of claudication. There were significant differences in alpha and beta diversity between the claudication and CLTI subgroups but none between the non-PAD and PAD groups overall. There were multiple significantly differentially abundant microbial features in the PAD group compared to non-PAD controls, including species within the genera Blautia and Clostridium . Metabolite profiles were also significantly different between the PAD and non-PAD groups, including higher abundance of the short chain fatty acid butyrate in the non-PAD controls (p=0.02). Network analyses identified three clusters of species with higher relative abundance in the claudication group compared to the CLTI group, and members of these clusters included putative butyrate producers. Conclusions: We identified specific microbial and metabolomic patterns associated with the clinical presentation of PAD and highlight a potential role for microbially-mediated butyrate in disease state.

Mechanisms of TFR cell-mediated regulation of microbiota-reactive IgA responses

Abstract The rising prevalence of food allergies impacting over 10% of the U.S. population requires innovative diagnostic approaches and therapeutic interventions. Gut microbiota alterations play a crucial role in food allergy development, with immunoglobulin IgA (IgA) actively regulating gut microbiome composition. While T follicular helper (TFH) cells aid in high-affinity antigen-specific IgA production, T follicular regulatory (TFR) cells' role in generating microbiota-specific IgA remains unclear. Using a unique TFR cell-deficient mouse model (Bcl6FC) and flow cytometry staining, we found increased fecal IgA-coated bacteria over time in Bcl6FC compared to WT mice after sensitization. IgA-seq revealed differential baseline microbiota IgA-coating in naïve Bcl6FC, displaying increased alpha diversity and more taxa with higher relative abundance than WT mice. Calculating the IgA-index demonstrated elevated IgA binding in Bcl6FC mice to specific taxa, primarily Firmicute members, indicating TFR cells' suppression of taxon-specific IgA in the peanut allergy model. Ongoing experiments, including the adoptive transfer of WT TFR cells into Bcl6FC mice and the assessment of IgA-coated biome function via Fecal Microbiota Transplantation (FMT) into germ-free mice in a peanut allergy model, aim to validate TFR cells' role in generating microbiota-specific IgA responses. This contributes essential insights for potential therapeutic antibodies targeting specific commensals.

Bacterial diversity and biopotentials of Hamtah glacier cryoconites, Himalaya.

Cryoconite is a granular structure present on the glaciers and ice sheets found in polar regions including the Himalayas. It is composed of organic and inorganic matter which absorb solar radiations and reduce ice surface albedo, therefore impacting the melting and retreat of glaciers. Though climate warming has a serious impact on Himalayan glaciers, the biodiversity of sub-glacier ecosystems is poorly understood. Moreover, cryoconite holes are unique habitats for psychrophile biodiversity hotspots in the NW Himalayas, but unfortunately, studies on the microbial diversity of such habitats remain elusive. Therefore, the current study was designed to explore the bacterial diversity of the Hamtah Glacier Himalaya using both culturable and non-culturable approaches. The culturable bacterial count ranged from 2.0 × 103 to 8.8 × 105 colony-forming units (CFUs)/g at the different locations of the glacier. A total of 88 bacterial isolates were isolated using the culturable approach. Based on the 16S ribosomal RNA gene (16S rRNA), the identified species belong to seven genera, namely, Cryobacterium, Duganella, Janthinobacterium, Pseudomonas, Peribacillus, Psychrobacter, and Sphingomonas. In the non-culturable approach, high-throughput sequencing of 16S rRNA genes (using MiSeq) showed unique bacterial community profiles and represented 440 genera belonging to 20 phyla, namely, Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Acidobacteria, Planctomycetes, Cyanobacteria, Verrucomicrobia, Spirochaetes, Elusimicrobia, Armatimonadetes, Gemmatimonadetes, Deinococcus-Thermus, Nitrospirae, Chlamydiae, Chlorobi, Deferribacteres, Fusobacteria, Lentisphaerae, and others. High relative abundances of Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were observed in the samples. Phototrophic (Cyanobacteria and Chloroflexi) and nitrifier (Nitrospirae) in bacterial populations indicated sustenance of the micro-ecosystem in the oligotrophic glacier environment. The isolates varied in their phenotypic characteristics, enzyme activities, and antibiotic sensitivity. Furthermore, the fatty acid profiles of bacterial isolates indicate the predominance of branched fatty acids. Iso-, anteiso-, unsaturated and saturated fatty acids together constituted a major proportion of the total fatty acid composition. High cold-adapted enzyme activities such as lipase and cellulase expressed by Cryobacterium arcticum (KY783365) and protease and cellulase activities by Pseudomonas sp. strains (KY783373, KY783377-79, KY783382) provide evidence of the possible applications of these organisms. Additionally, antibiotic tests indicated that most isolates were sensitive to antibiotics. In conclusion, the present study contributed for the first time to bacterial diversity and biopotentials of cryoconites of Hamtah Glacier, Himalayas. Furthermore, the cold-adapted enzymes and polyunsaturated fatty acids (PUFAs) may provide an opportunity for biotechnology in the Himalayas. Inductively coupled plasma mass spectrometry (ICPMS) analyses showed the presence of several elements in cryoconites, providing a clue for the accelerating melting and retreating of the Hamtah glacier.

Longitudinal changes in bifidobacterial population during the first two years of life.

Early life microbiota encompasses of a large percentage of Bifidobacterium, while it is not sufficiently understood how the Bifidobacterium population develops after infant's birth. Current study investigated the longitudinal changes in Bifidobacterium population during the first two years of life in 196 term born infants (1,654 samples) using 16S rRNA-23S rRNA internal transcribed spacer (ITS) sequence analysis. Throughout the first two years of life, Bifidobacterium breve, Bifidobacterium longum subsp. longum and Bifidobacterium adolescentis were most dominant and prevalent in the Bifidobacterium population, while B. breve had the highest relative abundance and prevalence during the first week of life and it was taken over by B. longum subsp. longum around two years after birth. Sampling time points, early antibiotic(s) exposure (effect only measurable within a month after birth), delivery mode (effect still detectable two-months after birth) and feeding mode (effect lasted until six months after birth), significantly contributed to the overall variation in the bifidobacterial population. From six months onwards, introducing of solid food and cessation of breastfeeding were accompanied with drastic changes in the composition in bifidobacterial population. Altogether, current study confirmed the effect of potential contributors to the longitudinal changes within the bifidobacterial population during the first two years of life. Registered at https://clinicaltrials.gov: NCT02536560.

Interplay between green-synthesized nanoparticles and plant performance is mediated by the microbial community in the rhizocompartments

Numerous green-synthesized nanoparticles are being evaluated for their potential application in soil, yet understanding their influence on plant performance and their rhizocompartments associated microbes is a gap that needs to be addressed. In this study, we investigated how applying iron oxide nanoparticles (control 0, low 25 and high 50 mg/kg) impacted the rhizocompartments associated microbial communities and plant secondary metabolites grown in natural soil microcosm. The transcriptional analysis showed that the majority of artemisinin and flavonoid biosynthetic pathway genes were significantly upregulated in plants with the application of low concentration of green-synthesized iron oxide nanoparticles (FeO.NPs) when compared with control plants, suggesting a fine collaboration between these metabolites’ pathways, as indicated by a remarkable increase in artemisinin content (2-fold), ferulic acid (7.6-fold), luteolin (4.3-fold) and syringic acid (6.2-fold). The response of rhizocompartments microbial communities and associated soil enzymes was investigated using high-throughput sequencing and profiler test kits, respectively. The soil microbial community structure was altered upon FeO.NPs exposure in both low and high treated soils as indicated by multivariate analysis. For instance, bacterial phyla Bacteroidetes and Gemmatimonadetes and fungal phyla Ascomycota demonstrated a significant rise in relative abundance in both the rhizosphere and rhizoplane in low and high treatments relative to the control. Moreover, genera level analysis revealed that Cupriavidus, Vibrionimonas, and Burkholderia displayed higher relative abundance (p < 0.05) in low FeO.NPs concentration while Giaella and Nonomuraea didn't show any noticeable response to FeO.NPs. In terms of fungal genera, Oidiodendron and Cryptococcus showed high relative abundance under low treatment. The altered microbiome profile is possibly associated with soil enzymes, for instance, urease and catalase activities were increased by 1.76 and 1.71-fold, respectively in low FeO.NPs. Thus, this study demonstrates the effects of FeO.NPs gradients on plant secondary metabolites and soil enzyme activities, while contributing new insights into their specific impacts on the microbial community composition in the rhizocompartments of plant root system.

Effects of Prolonged Fasting on Cloacal Microbiota of Crotalus durissus with Different Corporal Scores

Aims: This study provides a detailed analysis of the composition and diversity of the bacterial community within the cloacal cavity of Crotalus durissus (Cascavel) under the influence of diet and the corporal score of breeding snakes through metagenomics analysis. For this aim, the study also provides a body condition score protocol for the classification of snakes as thin, normal, and obese. Study Design: The experimental groups were established from snake body conditions such as visibility of ribs, the aspect of the side view, the upper and ventral view, and the aspect of the final portion, of the neck and square bone. Place and Duration of Study: The research was conducted at S-Inova Laboratory at Don Bosco Catholic University, between December 2017 and February 2019 (Mato Grosso do Sul, Brazil). Methodology: There are 3 groups of score corporations: thin (n=3), normal (n=3), and obese (n=3). The first sample of each animal was obtained 7 days after feeding and the second sample after 50 days of fasting. The metagenomic DNA was extracted from all 18 swab samples through DNeasy® PowerSoil® Kit (Qiagen). Thereafter the samples were submitted to sequencing, performed using the 2 x 250bp paired-end sequencing on a single run of an Illumina HiSeq, followed by the application of bioinformatics tools. Results: The most representative phyllo for all the samples was Proteobacteria (69,4%), followed by Bacteroidetes (19,2%) and Synergists (11,2%). In the group of obese snakes, the phylum Proteobacteria still being the group with the higher relative abundance in the two moments, with a decrease of 9,6%, as well as the phylum Bacteroidetes which decreased by 5,5% in the second moment (after fasting). Differently, the groups of the normal and thin have a decrease of 37,2% and 29,4% respectively of the phylum Proteobacteria and an increase of the relative abundance of 35% and 27,9% of the phylum Bacteroidetes. Before prolonged fasting the groups obtained 213 shared OTUs which reduced to 206 after the prolonged fasting, suggesting that, in general, the treatment influences microbial communities of the groups, which was possible to observe when analyzed and compared individually. The index of Shannon diversity showed that before the fasting, the groups of obese snakes and normal presented a bigger richness of species, differently from the thin group that showed more diversity after 50 days of fasting. The variance analysis showed that the obese snakes presented a bigger proximity to the samples collected before the prolonged fasting. The samples showed greater proximity in PCA analyses and ANOVA when considering the prolonged fasting time than when compared by body score. Conclusion: With this study, it was possible to conclude that prolonged fasting can influence the cloacal microbiota of the snake Crotalus durissus, except in the individuals considered obese.

Type Abundance and Relative Abundance of Macrozoobentos in the Intertidal Zone of Marabatuan Island, Kotabaru, Indonesia

The structure of macrozoobenthos communities plays a crucial role in aquatic ecosystems because most of them are in the second or third trophic level. Components of macrozoobenthos community structure include species and abundance, species diversity index, species uniformity index, dominance index. The research aims to analyze species abundance and relative abundance of macrozoobenthos in the intertidal zone of Marabatuan Island, Kotabaru, Indonesia. The research location is on Marabatuan Island, Pulau Sembilan District, Kotabaru Regency, South Kalimantan Province. The highest relative abundance (KR) was at station 3, namely the species Ophiocoma erinaceus, from the Asteroidea class, the second highest value was at station 2 with the species Holothuria atra and at station 1 of the same species, namely Holothuria atra from the Asteroidea. The lowest relative abundance was at station 1 of the Linckia laevigata species. The Diversity Index (H') of macrozoobenthos at all stations is in the medium criteria.

Picoplanktonic methane production in eutrophic surface waters

Abstract. Over the past decade, extensive research has delved into the methane (CH4) paradox, which involves aerobic CH4 production. We present noteworthy observations of CH4 oversaturation within the surface layer of the central Chile upwelling zone (36° S, 73° W) over two consecutive seasonal cycles (2018–2021). Complementing these observations, CH4 cycling experiments were conducted, utilizing distinct plankton fractions (encompassing the natural planktonic community, fractions &lt; 150, &lt; 3 and &lt; 0.2 µm), in different productivity periods of phytoplanktonic production and composition throughout the year. Our findings underscore the pivotal role of picoplankton (&lt; 3 µm) in CH4 production on the ocean surface, contrasting with the limited contribution of larger microorganisms (&lt; 150 µm). Notably, incubations with methylated substrates, such as methylphosphonic acid (MPn) and trimethylamine (TMA), induce heightened CH4 production within the picoplanktonic fraction. This phenomenon is consistently observed during both upwelling (austral spring–summer) and non-upwelling (winter) seasons, with significance in the latter period, when Synechococcus sp. exhibits notably high relative abundance. Long-term microcosm experiments highlight the crucial roles played by heterotrophic bacteria and cyanobacteria in methylotrophic methanogenesis. This process enhances CH4 production, facilitated by the recycling of dissolved organic carbon (DOC). Picoplankton emerges as a pivotal factor influencing the recycling of methylated substrates, and it is responsible for maintaining CH4 supersaturation. These findings provide valuable insights into the biogeochemical processes driving CH4 dynamics, particularly in highly productive upwelling areas.

Long-term vegetation restoration promotes lignin phenol preservation and microbial anabolism in forest plantations: Implications for soil organic carbon dynamics

Vegetation restoration contributes to soil organic carbon (C; SOC) sequestration through the accumulation of plant and microbial residues, but the mechanisms underlying this microbially mediated process are not well resolved. To depict the dynamics of plant- and microbial-derived C in restored forest ecosystems, soil samples were collected from Robinia pseudoacacia plantations of different stand ages (15, 25, 35, 45 years old) established on degraded wheat fields. The results showed that the degree of lignin phenol oxidation decreased with increasing stand age (P < 0.05), and hemicellulose-degrading genes were detected at higher relative abundances than other functional gene categories, indicating selective preservation of recalcitrant lignin phenols. Despite both glucosamine (R2 = 0.61, P < 0.001) and muramic acid (R2 = 0.37, P < 0.001) contents trending upward over time, fungal residual C accounted for a greater proportion of SOC compared with bacterial residual C. Accordingly, fungal residual C, which exhibited a similar response pattern as total microbial residual C to vegetation restoration, was considered a major contributor to the SOC pool. These results provided evidence that long-term vegetation restoration enhanced SOC sequestration in R. pseudoacacia forest by promoting the preservation of plant-derived lignin phenols and concomitant microbial anabolism. Partial least squares-discriminant analysis identified two important ecological clusters (i.e., modules) in the fungal network that profoundly influenced lignin phenol oxidation (P < 0.05) and microbial residual C accumulation (P < 0.01). Among the dominant taxa in microbial networks, the bacterial phyla Proteobacteria and Acidobacteriota had potential to degrade recalcitrant C compounds (e.g., cellulose, lignin), whereas the fungal phylum Ascomycota could outcompete for labile C fractions (e.g., dissolved organic C). Findings of this study can enable a mechanistic understanding of SOC stability driven by microbial turnover in restored forest ecosystems.

Bacterial Communities on Degraded Prehistoric Rock Paintings in Maros-Pangkep Global Geopark

391 Bacterial Communities on Degraded Prehistoric Rock Paintings in Maros-Pangkep Global Geopark Nur Haedar1*, Muhammad Iqram1, Ambeng1, Yusriana2, Dody Priosambodo1, and Rustan Lebe3 1Biology Department, Faculty of Mathematics and Natural Sciences, Hasanuddin University, Makassar 90245 Indonesia 2Archaeology Department, Faculty of Cultural Science, Hasanuddin University, Makassar 90245 Indonesia 3Indonesian Heritage Agency, Ministry of Education, Culture, Research, and Technology, Jakarta 10110 Indonesia The Maros-Pangkep karst region is a natural landscape located inside the UNESCO Global Geopark, extending across two regencies in South Sulawesi. There are at least 135 prehistoric caves, of which about 78 of them still have traces of relics in the form of rock paintings. One thing that has made this region renowned is the presence of the world’s oldest ancient rock painting, ca. 40,000 years old, in an ancient cave. Unfortunately, many paintings have been experiencing degradation marked by color changes and exfoliation, which are thought to be partially caused by the colonization of bacterial biofilms. The present study, therefore, aimed to delineate the bacterial diversity of biofilms present in ancient rock paintings. Samples were collected from three different caves in the region and analyzed using Oxford Nanopore Technology, sequencing the full-length 16S rRNA gene (V1–V9 regions). The results showed that Firmicutes was the dominant bacterial taxon in both Leang Jing and Leang Parewe, representing 95 and 82% of the total bacterial community, respectively. In Leang Bulu Sipong, we observed a high relative abundance of both Betaproteobacteria (30%) and Firmicutes (44%). Among the taxa detected, some genera – including Cupriavidus, Bacillus, Lysinibacillus, Paenibacillus, Geobacillus, and Pseudomonas – are linked to the carbonate precipitation and rock weathering, which could give a clue on the role of bacterial activities in corroborating the biodegradation on the ancient rock arts. Despite the result of microbial diversity in the rock paintings, it is necessary to do further study on the mechanism of degradation performed by the bacteria. This will support the effort of local authorities to conserve local heritage aged a thousand years.

Recent alcohol intake impacts microbiota in adult burn patients

Alcohol use is associated with an increased incidence of negative health outcomes in burn patients due to biological mechanisms that include a dysregulated inflammatory response and increased intestinal permeability. This study used phosphatidylethanol (PEth) in blood, a direct biomarker of recent alcohol use, to investigate associations between a recent history of alcohol use and the fecal microbiota, short chain fatty acids, and inflammatory markers in the first week after a burn injury for nineteen participants. Burn patients were grouped according to PEth levels of low or high and differences in the overall fecal microbial community were observed between these cohorts. Two genera that contributed to the differences and had higher relative abundance in the low PEth burn patient group were Akkermansia, a mucin degrading bacteria that improves intestinal barrier function, and Bacteroides, a potentially anti-inflammatory bacteria. There was no statistically significant difference between levels of short chain fatty acids or intestinal permeability across the two groups. To our knowledge, this study represents the first report to evaluate the effects of burn injury and recent alcohol use on early post burn microbiota dysbiosis, inflammatory response, and levels of short chain fatty acids. Future studies in this field are warranted to better understand the factors associated with negative health outcomes and develop interventional trials.

Powdery mildew-induced changes in phyllosphere microbial community dynamics of cucumber.

As an important habitat for microorganisms, the phyllosphere has a great impact on plant growth and health, and changes in phyllosphere microorganisms are closely related to the occurrence of leaf diseases. However, there remains a limited understanding regarding alterations to the microbial community in the phyllosphere resulting from pathogen infections. Here, we analyzed and compared the differences in phyllosphere microorganisms of powdery mildew cucumber from three disease severity levels (0% < L1 < 30%, 30% ≤ L2 < 50%, L3 ≥ 50%, the number represents the lesion coverage rate of powdery mildew on leaves). There were significant differences in α diversity and community structure of phyllosphere communities under different disease levels. Disease severity altered the community structure of phyllosphere microorganisms, Rosenbergiella, Rickettsia, and Cladosporium accounted for the largest proportion in the L1 disease grade, while Bacillus, Pantoea, Kocuria, and Podosphaera had the highest relative abundance in the L3 disease grade. The co-occurrence network analysis of the phyllosphere microbial community indicated that the phyllosphere bacterial community was most affected by the severity of disease. Our results suggested that with the development of cucumber powdery mildew, the symbiotic relationship between species was broken, and the entire bacterial community tended to compete.

Ethoxyquin attenuates enteric oxidative stress and inflammation by promoting cytokine expressions and symbiotic microbiota in heat-stressed broilers

Intestinal oxidative stress in broilers is produced by chronic heat stress (HS) and has a negative impact on poultry performance as it induces intestinal inflammation and promotes the invasion of gram-negative bacteria, such as bacterial lipopolysaccharide (LPS). Therefore, dietary inclusion of the antioxidant compound, ethoxyquin (EQ), could improve enteric antioxidant capacity, immune responses, and the epithelial barrier, and maintain the symbiotic gut microbiota community. To investigate the effects of EQ supplementation on alleviating enteric oxidative stress in heat-stressed broilers, 200 one-day-old male Ross 308 broilers were randomly assigned to 4 groups (n = 50 chicks/group; n = 10 chicks/replicate) and fed a basal diet supplemented with 0 (CT), 50 (EQ-50), 100 (EQ-100), and 200 (EQ-200) mg EQ/ kg-1 for 5 wk. The chicks were raised in floor pens inside the broiler farm at a temperature and humidity index (THI) of 29 from d 21 to d 35. Growth performance traits, relative organ index, hepatic antioxidant enzymes, serum immunity, total adenylate, and cytokine activities were improved in the EQ-50 group (linear or quadratic P < 0.05), promoting the relative mRNA expression of cytokine gene-related anti-inflammatory and growth factors. A distinct microbial community colonised the gut microbiota in the EQ-50 group, with a high relative abundance of Lactobacillus, Ligilactobacillus, Limosilactobacillus, Pediococcus, Blautia, and Faecalibacterium compared to the other groups. Dietary supplementation with 50 mg EQ/ kg-1 for 5 wk attenuates enteric oxidative stress and intestinal inflammation by enhancing serum immune and cytokine content (IgG, IL-6, and TGF-β,) and symbiotic microbiota in heat-stressed broilers. EQ promotes the expression of Hsp70, SOD2, GPx 4, IL-6, and IGF-1 cytokine gene-related anti-inflammatory and growth factors in heat-stressed hepatic broilers. Collectively, EQ-50 could be a suitable feed supplement for attenuating enteric oxidative stress and intestinal inflammation, thereby promoting the productivity of heat-stressed broilers.

Environmental factors and particle size shape the community structure of airborne total and pathogenic bacteria in a university campus.

Given the dense population on university campuses, indoor and outdoor airborne bacterial contamination may lead to the rapid spread of diseases in a university environment. However, there are few studies of the characteristics of airborne and pathogenic bacterial communities in different sites on a university campus. In this study, we collected particulate matter samples from indoor and outdoor locations at a university in Bengbu City, Anhui Province, China, and analyzed the community characteristics of airborne and pathogenic bacteria using a high-throughput sequencing technique. The results showed that the composition of the dominant airborne and pathogenic bacterial communities was consistent among sites at the phylum and genus levels, with differences in their relative abundance. There were significant differences in the structure of the airborne and pathogenic bacterial communities between indoor and outdoor sites (p < 0.05). An analysis of similarities (ANOSIM) indicated that the structure of airborne bacterial communities in indoor sites was influenced by the room occupancy rate, ventilation conditions, and the extent of indoor furnishing (p < 0.05), while the structure of pathogenic bacterial communities was influenced by the number of individuals and spatial dimensions (p < 0.05). The impact of particle size on the structure of airborne and pathogenic bacterial communities was relatively minor. A total of 194 suspected pathogenic bacterial species were identified, accounting for 0.0001-1.3923% of the total airborne bacteria, all of which were conditional pathogens. Among them, Saccharopolyspora rectivirgula, Acinetobacter johnsonii, and Moraxella osloensis exhibited relatively high relative abundance, accounting for 24.40, 16.22, and 8.66% of the total pathogenic bacteria, respectively. Moreover, 18 emerging or re-emerging pathogenic bacterial species with significant implications for human health were identified, although their relative abundance was relatively low (0.5098%). The relative abundance of pathogenic bacteria in indoor environments was significantly higher than outdoors, with the laboratory and dormitory having the highest levels. The findings of this study provide valuable guidance for the prevention and control of airborne bacterial contamination and the associated health risks in both a campus environment and other public spaces with high occupancy rates.