Evolution and stability of complex microbial communities driven by trade-offs.

Microbial communities are ubiquitous in nature and play an important role in ecology and human health. Cross-feeding is thought to be core to microbial communities, though it remains unclear precisely why it emerges. Why have multi-species microbial communities evolved in many contexts and what protects microbial consortia from invasion? Here, we review recent insights into the emergence and stability of coexistence in microbial communities. A particular focus is the long-term evolutionary stability of coexistence, as observed for microbial communities that spontaneously evolved in the E. coli long-term evolution experiment (LTEE). We analyze these findings in the context of recent work on trade-offs between competing microbial objectives, which can constitute a mechanistic basis for the emergence of coexistence. Coexisting communities, rather than monocultures of the 'fittest' single strain, can form stable endpoints of evolutionary trajectories. Hence, the emergence of coexistence might be an obligatory outcome in the evolution of microbial communities. This implies that rather than embodying fragile metastable configurations, some microbial communities can constitute formidable ecosystems that are difficult to disrupt.

Plasticity of growth laws tunes resource allocation strategies in bacteria.

Bacteria like E. coli grow at vastly different rates on different substrates, however, the precise reason for this variability is poorly understood. Different growth rates have been attributed to 'nutrient quality', a key parameter in bacterial growth laws. However, it remains unclear to what extent nutrient quality is rooted in fundamental biochemical constraints like the energy content of nutrients, the protein cost required for their uptake and catabolism, or the capacity of the plasma membrane for nutrient transporters. Here, we show that while nutrient quality is indeed reflected in protein investment in substrate-specific transporters and enzymes, this is not a fundamental limitation on growth rate, at least for certain 'poor' substrates. We show that it is possible to turn mannose, one of the 'poorest' substrates of E. coli, into one of the 'best' substrates by reengineering chromosomal promoters of the mannose transporter and metabolic enzymes required for mannose degradation. This result falls in line with previous observations of more subtle growth rate improvement for many other carbon sources. However, we show that this faster growth rate comes at the cost of diverse cellular capabilities, reflected in longer lag phases, worse starvation survival and lower motility. We show that addition of cAMP to the medium can rescue these phenotypes but imposes a corresponding growth cost. Based on these data, we propose that nutrient quality is largely a self-determined, plastic property that can be modulated by the fraction of proteomic resources devoted to a specific substrate in the much larger proteome sector of catabolically activated genes. Rather than a fundamental biochemical limitation, nutrient quality reflects resource allocation decisions that are shaped by evolution in specific ecological niches and can be quickly adapted if necessary.

Vitamin D3 promotes fish oocyte development by directly regulating gonadal steroid hormone synthesis†.

Vitamin D receptors and vitamin D3-metabolizing enzymes have been found to be highly expressed in the ovaries and spermatophores of fish. However, the role of vitamin D3 on fish gonadal development has rarely been reported. In this study, 2-month-old female zebrafish were fed with different concentrations of vitamin D3 diets (0, 700, 1400, and 11 200 IU/kg) to investigate the effects of vitamin D3 on ovarian development. The diet with 0 IU/kg vitamin D3 resulted in elevated interstitial spaces, follicular atresia, and reproductive toxicity in zebrafish ovaries. Supplementation with 700 and 1400 IU/kg of vitamin D3 significantly increased the oocyte maturation rate; upregulated ovarian gonadal steroid hormone synthesis capacity; and elevated plasma estradiol, testosterone, and ovarian vitellogenin levels. Furthermore, the current study identified a vitamin D response element in the cyp19a1a promoter and demonstrated that 1.25(OH)2D3-vitamin D response directly activated cyp19a1a production through activating the vitamin D response element. In conclusion, this study shows that an appropriate concentration of vitamin D3 can promote zebrafish ovarian development and affect vitellogenin synthesis through the vdr/cyp19a1a/er/vtg gene axis.

Peer victimization and non-suicidal self-injury among high school students: the mediating role of social anxiety, mobile phone addiction, and sex differences.

BACKGROUND: Peer victimization (PV) is one of the major causes of non-suicidal self-injury. Non-suicidal self-injury (NSSI), peer victimization, social anxiety, and mobile phone addiction are significantly related; however, the interaction mechanism and effect of sex differences remain to be determined. OBJECTIVE: Herein, we investigated the relationship between peer victimization and NSSI among Chinese high school students. We also explored the chain mediating roles of social anxiety and mobile phone addiction and the regulatory role of sex. The findings of this study provide insights for theoretical interventions based on internal mechanisms. METHOD: A self-reported survey of 14,666 high school students from Sichuan County was conducted using a peer victimization scale, NSSI scale, social anxiety scale, and mobile phone addiction scale. A self-administered questionnaire was used to capture sociodemographic information. RESULTS: Peer victimization, social anxiety, and mobile phone addiction were positively correlated with NSSI. Peer victimization had significant direct predictive effects on NSSI (95% CI: 0.341, 0.385) and significant indirect predictive effects on NSSI through social anxiety (95% CI: 0.008, 0.019) or mobile phone addiction (95% CI: 0.036, 0.053). Peer victimization had significant indirect predictive effects on NSSI through social anxiety as well as mobile phone addiction (95% CI: 0.009, 0.014). The first stage (predicting the effect of peer victimization on NSSI) and the third stage (predicting the effect of mobile phone addiction on NSSI) were both moderated by sex. CONCLUSIONS: Peer victimization could directly predict NSSI and indirectly predict NSSI through social anxiety and mobile phone addiction. Thus, social anxiety and mobile phone addiction exhibited chain mediating effects between peer victimization and NSSI in high school students; moreover, sex might be involved in the regulation of the mediation process.

Mental health priorities and cultural-responsiveness of the Mental Health First Aid (MHFA) training for Asian immigrant populations in Greater Boston, Massachusetts.

BACKGROUND: Asians and Asian Americans have the lowest rate of mental health service utilization (25%) in the US compared to other racial/ethnic groups (39 - 52%), despite high rates of depression, anxiety, and suicidal ideation. The lack of culturally-responsive mental health trainings hinders access to mental health services for these populations. We assessed the mental health priorities of Asian communities in Greater Boston and evaluated cultural responsiveness of the Mental Health First Aid (MHFA), a first-responder training teaching participants skills to recognize signs of mental health and substance use challenges, and how to appropriately respond. METHODS: This is community-based participatory research with the Boston Chinatown Neighborhood Center (BCNC), Asian Women For Health (AWFH), and the Addressing Disparities in Asian Populations through Translational Research (ADAPT) Coalition. We conducted focus groups with community-based organization staff and community members to assess mental health priorities of Asian populations in Boston, MA. We then evaluated the utility and cultural-responsiveness of the English-language MHFA for Asian populations through pre- and post-training questionnaires and focus groups with community participants. Paired t-tests were used to evaluate questionnaire responses. Thematic analysis was used to analyze interviews. RESULTS: In total, ten staff and eight community members participated in focus groups, and 24 community members completed the MHFA and pre- and post-training questionnaires. Common mental health challenges in the Asian communities reported by participants were loneliness, high stigma around mental illnesses, academic pressure, and acculturation stress. Compared to pre-training, MHFA participants demonstrated lower personal mental health stigma (p < 0.001) and higher mental health literacy (p = 0.04) post-training. Participants also noted the lack of data statistics and case studies relevant to Asian populations in the training, and desired the training be offered in languages spoken by Asian ethnic subgroups (e.g., Chinese, Vietnamese). CONCLUSION: Cultural-responsiveness of the MHFA for Asian populations could be improved with the inclusion of data and case studies that capture common mental health challenges in the Asian communities and with translation of the MHFA to non-English languages predominant in Asian communities. Increasing the cultural relevance and language accessibility of the MHFA could facilitate wider adoption of these trainings across communities and help to reduce mental health stigma and gaps in literacy and service utilization.

Factors associated with SARS-CoV-2 vaccine hesitancy after stroke: a cross-sectional study.

BACKGROUND: The vaccination status of post-stroke patients, who are at high risk of severe outcomes from Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is a significant concern, yet it remains unclear. We aimed to explore the vaccination status, factors associated with vaccine hesitancy, and adverse effects after vaccination among post-stroke patients. METHODS: This multi-center observational study enrolled hospitalized post-stroke patients from six Chinese hospitals (Oct 1, 2020 - Mar 31, 2021), examining vaccine uptake and self-reported reasons for vaccine hesitancy, utilizing logistic regression to investigate risk factors for vaccine hesitancy, and recording any adverse reactions post-vaccination. RESULTS: Of the total 710 post-stroke patients included in the study, 430 (60.6%) had completed the recommended full-3 dose SARS-CoV-2 vaccination, with 176 (24.8%) remaining unvaccinated. The most common reasons for vaccine hesitancy were concerns about vaccine side effects (41.5%) and impaired mobility (33.9%). Logistic regression identified advanced age (aOR = 1.97, 95%CI: 1.36-2.85, P = 0.001), lower Barthel Index score (aOR = 0.88, 95%CI: 0.82-0.93, P = 0.018), higher Modified Rankin Scale score (aOR = 1.85, 95%CI: 1.32-2.56, P = 0.004), and poorer usual activity level of EuroQol 5-Dimension (aOR = 2.82, 95%CI: 1.51-5.28, P = 0.001) as independent risk factors for vaccine hesitancy. Approximately 14.8% reported minor adverse reactions, mainly pain at the injection site. CONCLUSION: We found that post-stroke patients have insufficient SARS-CoV-2 vaccination rates, with key risk factors for vaccine hesitancy including concerns about side effects, advanced age, and functional impairments. No severe adverse reactions were observed among the vaccinated population.

Paospora carinifang n. gen., n. sp. (Microsporidia: Spragueidae), a parasite of the ridgetail white prawn, Palaemon carinicauda.

A new microsporidian disease of the pond-reared ridgetail white prawn, Palaemon carinicauda, was found in China. Light microscopy, pathology, and scanning electron microscopy showed that the parasite infected the host's skeletal muscle tissue and formed spherical sporophorous vesicles (SPOVs). Electron microscopy revealed that its merogonic life stages developed in direct contact with the host cytoplasm. The sporogonic life stages underwent octosporoblastic sporogony with the formation of eight uninucleate spores in each SPOV. Fresh SPOVs were 5.4 ± 0.55 µm in diameter. The octospores were oval and measured 2.3 × 1.5 µm (fresh) and 1.96 × 1.17 µm (fixed). The isofilar polar filament was coiled with 9-10 turns and arranged in two rows. Phylogenetic analysis based on the SSU rRNA gene suggests that this microsporidium has close affinities with members of the genera Potaspora and Apotaspora, but represents an independent generic taxon. We therefore propose the establishment of a new genus and species (Paospora carinifang n. gen., n. sp.) within the family Spragueidae. We also propose a taxonomic revision to transfer Potaspora macrobrachium to this new genus and reclassify it as Paospora macrobrachium comb. nov.

Stromal HIF2 Regulates Immune Suppression in the Pancreatic Cancer Microenvironment.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) has a hypoxic, immunosuppressive stroma that contributes to its resistance to immune checkpoint blockade therapies. The hypoxia-inducible factors (HIFs) mediate the cellular response to hypoxia, but their role within the PDAC tumor microenvironment remains unknown. METHODS: We used a dual recombinase mouse model to delete Hif1α or Hif2α in α-smooth muscle actin-expressing cancer-associated fibroblasts (CAFs) arising within spontaneous pancreatic tumors. The effects of CAF HIF2α expression on tumor progression and composition of the tumor microenvironment were evaluated by Kaplan-Meier analysis, reverse transcription quantitative real-time polymerase chain reaction, histology, immunostaining, and by both bulk and single-cell RNA sequencing. CAF-macrophage crosstalk was modeled ex vivo using conditioned media from CAFs after treatment with hypoxia and PT2399, an HIF2 inhibitor currently in clinical trials. Syngeneic flank and orthotopic PDAC models were used to assess whether HIF2 inhibition improves response to immune checkpoint blockade. RESULTS: CAF-specific deletion of Hif2α, but not Hif1α, suppressed PDAC tumor progression and growth, and improved survival of mice by 50% (n = 21-23 mice/group, Log-rank P = .0009). Deletion of CAF-HIF2 modestly reduced tumor fibrosis and significantly decreased the intratumoral recruitment of immunosuppressive M2 macrophages and regulatory T cells. Treatment with the clinical HIF2 inhibitor PT2399 significantly reduced in vitro macrophage chemotaxis and M2 polarization, and improved tumor responses to immunotherapy in both syngeneic PDAC mouse models. CONCLUSIONS: Together, these data suggest that stromal HIF2 is an essential component of PDAC pathobiology and is a druggable therapeutic target that could relieve tumor microenvironment immunosuppression and enhance immune responses in this disease.

The Lnc-RNA APPAT Suppresses Human Aortic Smooth Muscle Cell Proliferation and Migration by Interacting With MiR-647 and FGF5 in Atherosclerosis.

PURPOSE: LncRNA-Atherosclerotic plaque pathogenesis-associated transcript (APPAT) could be detected in circulating blood and has been demonstrated to correlate with the development of atherosclerosis in our previous work. It could be a potential noninvasive biomarker for earlier diagnoses of clinical cardiovascular disease. Moreover, the expression of miR-647 increased in ox-LDL-treated vascular smooth muscle cells and peripheral blood of patients with coronary heart disease. A negative correlation between APPAT and miR-647 was confirmed, and FGF5 was screened as molecular target of miR-647. However, it is largely unclear how APPAT, miR-647, and FGF5 interact and function in disease development. Here, we aim to explore the underlying molecular mechanism in this progression. MATERIALS AND METHODS: APPAT, miR-647, and FGF5 expression levels were detected by quantitative reverse transcription polymerase chain reaction; cell proliferation was detected by EdU incorporation assay; cell migration was detected by wound-healing assay; the molecular interaction of APPAT/FGF5 with miR-647 was verified by dual-luciferase reporter assay; the western blot was performed to determine the gene expression at protein levels; subcellular localizations of APPAT and miR-647 were observed by fluorescence in situ hybridization; cytosolic and nucleus fractionation assay was performed to further detect the distribution of miR-647. RESULTS: APPAT and miR-647 have inverse effects on human aortic smooth muscle cells' (HASMCs) proliferation and migration. APPAT negatively regulated the cell activity, whereas miR-647 did it in a positive way (p<0.05). Three pairs of molecular interplay were found: mutual negative regulation between APPAT and miR-647, APPAT downregulated FGF5, miR-647 regulation on FGF5 (p<0.05). Subcellular location assay confirmed the molecular interaction of APPAT and miR-647. CONCLUSIONS: APPAT could suppress the migration and proliferation of ox-LDL-treated HASMCs via interacting with miR-647 and FGF5. We revealed a nontypical competing endogenous RNA mechanism of long noncoding RNA in the progression of atherosclerosis.

Mycorrhizal diversity and community composition in co-occurring Cypripedium species.

Orchids commonly rely on mycorrhizal fungi to obtain the necessary resources for seed germination and growth. Whereas most photosynthetic orchids typically associate with so-called rhizoctonia fungi to complete their life cycle, there is increasing evidence that other fungi may be involved as well and that the mycorrhizal communities associated with orchids may be more diverse. Coexisting orchid species also tend to associate with different fungi to reduce competition for similar resources and to increase long-term population viability. However, few studies have related the mycorrhizal communities in the rhizosphere to communities found in the roots of closely related coexisting orchid species. In this study, we used high-throughput sequencing to investigate the diversity and community composition of orchid mycorrhizal fungi in the roots and the rhizosphere of four Cypripedium species growing in forests in Northeast China. The results showed that the investigated Cypripedium species associated with a wide variety of fungi including members of Tulasnellaceae, Psathyrellaceae, and Herpotrichiellaceae, whereas members of Russulaceae, Cortinariaceae, Thelephoraceae, and Herpotrichiellaceae showed high abundance in rhizosphere soils. The diversity of fungi detected in the rhizosphere soil was much higher than that in the roots. The observed variation in fungal communities in Cypripedium roots was not related to forest site or orchid species. On the other hand, variation in mycorrhizal communities of rhizosphere soil was significantly related to sampling site. These results indicate that orchid mycorrhizal communities in the rhizosphere display considerable variation among sites and that orchids use only a subset of the locally available fungi. Future studies focusing on the fine-scale spatial distribution of orchid mycorrhizal fungi and more detailed assessments of local environmental conditions will provide novel insights into the mechanisms explaining variation of fungal communities in both orchid roots and the rhizosphere.