Experimental identification and in silico prediction of bacterivory in green algae

While algal phago-mixotrophs play a major role in aquatic microbial food webs, their diversity remains poorly understood. Recent studies have indicated several species of prasinophytes, early diverging green algae, to be able to consume bacteria for nutrition. To further explore the occurrence of phago-mixotrophy in green algae, we conducted feeding experiments with live fluorescently labeled bacteria stained with CellTracker Green CMFDA, heat-killed bacteria stained with 5-(4,6-dichlorotriazin-2-yl) aminofluorescein (DTAF), and magnetic beads. Feeding was detected via microscopy and/or flow cytometry in five strains of prasinophytes when provided with live bacteria: Pterosperma cristatum NIES626, Pyramimonas parkeae CCMP726, Pyramimonas parkeae NIES254, Nephroselmis pyriformis RCC618, and Dolichomastix tenuilepis CCMP3274. No feeding was detected when heat-killed bacteria or magnetic beads were provided, suggesting a strong preference for live prey in the strains tested. In parallel to experimental assays, green algal bacterivory was investigated using a gene-based prediction model. The predictions agreed with the experimental results and suggested bacterivory potential in additional green algae. Our observations underline the likelihood of widespread occurrence of phago-mixotrophy among green algae, while additionally highlighting potential biases introduced when using prey proxy to evaluate bacterial ingestion by algal cells. © 2021, The Author(s).National Science FoundationOpen access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Morphological Characterization of Fungal Endophyte Community Structure in Leaf Tissue of Quercus rubra

Endophytic fungi occur in healthy tissues of plants, playing potentially important roles in the ecology and evolution of their hosts.We examined endophytic fungi in both asymptomatic and infected foliage of red oak (Quercus rubra) at Bard College, Annandale-On-Hudson, NY. In order to to evaluate morphotaxa, visual groupings and BLAST matches of sequence similarity were conducted. We used these methods to estimate endophyte diversity and species composition by investigating the relationships between leaf health and endophyte community structure. Using traditional ecological indices, I estimated endophyte diversity and spatial heterogeneity across two ecologically similar locations on the Bard campus. Foliar endophytes were recovered in culture from 89.58% of sampled leaf hole punches, yielding a total of 960 isolates that represented 131 distinct morphotypes. 84 rare morphotypes were recovered only once, whereas all other morphotypes were recovered from multiple leaves across locations. Sequence data from the nuclear ribosomal internal transcribed spacer (ITS) of the most prevalent morphotype confirmed reliability of morhpotypic groupings.This morphotype mapped to Sordariomycetes sp. genotype 483, a foliar endophyte isolated from Quercus montana. Endophytes morphological diversity did not differ in composition at either leaf or tree level indicating that the communities may be structured based on location. These preliminary results require a larger-scale, molecular characterization of these morphotypes before coming to a conclusion about endophyte host colonization preferences

Improving grade five students' recreational reading habits: An action research

<p>Reading is vital for learning. It makes a reader more empathetic, knowledgeable, and creative and stimulates imagination. It also helps in boosting communication, improving vocabulary and helps to discover the world. Given this context, the present study seeks to improve grade five students’ recreational reading habits through measures such as uninterrupted sustained silent reading, creating reading corner and providing reading incentives. Grounded on the pragmatism paradigm, the study employs convergent parallel design. The quantitative and qualitative data were collected through survey of 25 students and six students, respectively. The quantitative data was analysed using descriptive statistics. The qualitative data from interview were used to support the findings of quantitative data. The result of the current study revealed that intervention measures employed for this study are effective in enhancing grade five students’ attitude towards reading. The recreational reading habits also improved after implementing the intervention measures. In addition, it was also found that reading incentives motivates students the most followed by uninterrupted sustained silent reading. Therefore, teachers and parents need to encourage students to read by creating reading platform and providing incentives for the students to enhance their recreational reading habits.</p&gt

Commensal microbes provide first line defense against Listeria monocytogenes infection

Listeria monocytogenes is a foodborne pathogen that causes septicemia, meningitis and chorioamnionitis and is associated with high mortality. Immunocompetent humans and animals, however, can tolerate high doses of L. monocytogenes without developing systemic disease. The intestinal microbiota provides colonization resistance against many orally acquired pathogens, and antibiotic-mediated depletion of the microbiota reduces host resistance to infection. Here we show that a diverse microbiota markedly reduces Listeria monocytogenes colonization of the gut lumen and prevents systemic dissemination. Antibiotic administration to mice before low dose oral inoculation increases L. monocytogenes growth in the intestine. In immunodeficient or chemotherapy-treated mice, the intestinal microbiota provides nonredundant defense against lethal, disseminated infection. We have assembled a consortium of commensal bacteria belonging to the Clostridiales order, which exerts in vitro antilisterial activity and confers in vivo resistance upon transfer into germ free mice. Thus, we demonstrate a defensive role of the gut microbiota against Listeria monocytogenes infection and identify intestinal commensal species that, by enhancing resistance against this pathogen, represent potential probiotics

Impact of gut colonization with butyrate-producing microbiota on respiratory viral infection following allo-HCT

Respiratory viral infections are frequent in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HCT) and can potentially progress to lower respiratory tract infection (LRTI). The intestinal microbiota contributes to resistance against viral and bacterial pathogens in the lung. However, whether intestinal microbiota composition and associated changes in microbe-derived metabolites contribute to the risk of LRTI following upper respiratory tract viral infection remains unexplored in the setting of allo-HCT. Fecal samples from 360 allo-HCT patients were collected at the time of stem cell engraftment and subjected to deep, 16S ribosomal RNA gene sequencing to determine microbiota composition, and short-chain fatty acid levels were determined in a nested subset of fecal samples. The development of respiratory viral infections and LRTI was determined for 180 days following allo-HCT. Clinical and microbiota risk factors for LRTI were subsequently evaluated using survival analysis. Respiratory viral infection occurred in 149 (41.4%) patients. Of those, 47 (31.5%) developed LRTI. Patients with higher abundances of butyrate-producing bacteria were fivefold less likely to develop viral LRTI, independent of other factors (adjusted hazard ratio 5 0.22, 95% confidence interval 0.04-0.69). Higher representation of butyrate-producing bacteria in the fecal microbiota is associated with increased resistance against respiratory viral infection with LRTI in allo-HCT patients