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Evolutionary analyses of visual opsin genes in frogs and toads: Diversity, duplication, and positive selection
Get PDFAmong major vertebrate groups, anurans (frogs and toads) are understudied with regard to their visual systems, and little is known about variation among species that differ in ecology. We sampled North American anurans representing diverse evolutionary and life histories that likely possess visual systems adapted to meet different ecological needs. Using standard molecular techniques, visual opsin genes, which encode the protein component of visual pigments, were obtained from anuran retinas. Additionally, we extracted the visual opsins from publicly available genome and transcriptome assemblies, further increasing the phylogenetic and ecological diversity of our dataset to 33 species in total. We found that anurans consistently express four visual opsin genes (RH1, LWS, SWS1, and SWS2, but not RH2) even though reported photoreceptor complements vary widely among species. The proteins encoded by these genes showed considerable sequence variation among species, including at sites known to shift the spectral sensitivity of visual pigments in other vertebrates and had conserved substitutions that may be related to dim-light adaptation. Using molecular evolutionary analyses of selection (dN/dS) we found significant evidence for positive selection at a subset of sites in the dim-light rod opsin gene RH1 and the long wavelength sensitive cone opsin LWS. The function of sites inferred to be under positive selection are largely unknown, but a few are likely to affect spectral sensitivity and other visual pigment functions based on proximity to previously identified sites in other vertebrates. We also found the first evidence of visual opsin duplication in an amphibian with the duplication of the LWS gene in the African bullfrog, which had distinct LWS copies on the sex chromosomes suggesting the possibility of sex-specific visual adaptation. Taken together, our results indicate that ecological factors, such as habitat and life history, as well as behavior, may be driving changes to anuran visual systems
Anticancer Properties of Kaempferol on Cellular Signaling Pathways
No full textPolyhydroxy compounds are secondary metabolites that are ubiquitous in plants of higher genera. They possess therapeutic properties against a wide spectrum of diseases, including cancers, neurodegenerative disorders, atherosclerosis, as well as cardiovascular disease. The phytochemical flavonol (a type of flavonoid) kaempferol (KMP)(3, 5, 7-trihydroxy-2-(4-hydroxyphenyl)-4Hchromen-4-one) is abundant in cruciferous vegetables, including broccoli, kale, spinach, and watercress, as well as in herbs like dill, chives, and tarragon. KMP is predominantly hydrophobic in nature due to its diphenylpropane structure (a characteristic feature of flavonoids). Recent findings have indicated the promise of applying KMP in disease prevention due to its potential antioxidant, antimutagenic, antifungal, and antiviral activities. In the literature, there is evidence that KMP exerts its anticancer effects by modulating critical elements in cellular signal transduction pathways linked to apoptosis, inflammation, angiogenesis, and metastasis in cancer cells without affecting the viability of normal cells. It has been shown that KMP triggers cancer cell death by several mechanisms, including cell cycle arrest, caspase activation, metabolic alteration, and impacting human telomerase reverse-transcriptase gene expression. This review is aimed at providing critical insights into the influence of KMP on the intracellular cascades that regulate metabolism and signaling in breast, ovarian, and cervical cancer cells
Effects of Excessive Soil Phosphorus Accumulation on Loblolly Pine (Pinus taeda L.) Seedlings
Get PDFMany landowners in East Texas apply poultry litter to pastures as a source of nitrogen (N) for forage crops. After many years of repeated poultry litter application, soils can accumulate extremely high extractable phosphorus (P) concentrations, sometimes over 1000 mg kg-1 of plant available P. Landowners report the conversion of these pastures to loblolly pine (Pinus taeda L.) plantations is often problematic, with poor seedling survival and abnormal tree growth. This study was conducted to assess the effects of excessive soil phosphorus on loblolly pine seedlings. An outdoor pot study was conducted using bare root seedlings and triple superphosphate treatments to simulate different soil P concentrations of those from poultry litter applications. The treatments were a control, 250 mg kg-1, 500 mg kg-1, 750 mg kg-1, 1000 mg kg-1, and 1250 mg kg-1of plant available P with eight replications. Seedlings were grown for one growing season and measured periodically for survival, height and diameter growth, foliage color using a Munsell color transformation, and at the end of the study sampled for dry biomass (above and below ground), survivability, foliar nutrient content, and ground needle color Munsell color transformation comparison. Growth trends in the study were positive for growth relationship to P treatment level increase. However, at the end of the first growing season seedlings presented deficiency symptoms like needle tissue chlorosis and branch tip necrosis in the high P treatments. Trends in foliar nutrient content were an increase in zinc concentrations and a decrease in iron concentrations as phosphorus treatment level increased. Excess foliar phosphorus ratioed to iron and zinc emphasized a dilution effect or possible phosphorus:iron competitive interaction, especially with iron. Munsell color comparison between living and ground color showed a higher variability in ground color range in the 3-dimensional color space, as well as a higher significance between color and deficiency symptoms. Munsell color proved to be a useful tool to analyze the relationship between color and variable plant health
School Leadership Assessment of Teachers’ Work-Life Balance: Perceptions and Professional Learning Needs During a Global Health Pandemic
Get PDFThe purpose of this study was to better understand the work-life balance of educators teaching students during the Covid-19 health pandemic. Teachers face a multitude of challenges during this unprecedented time with a rapid shift from traditional face-to-face class to online learning resulting in a cyclical phenomenon for many teachers as schools have shifted back and forth between virtual and in-person settings in response to constantly changing coronavirus messaging. The findings identified three overarching themes related to teachers’ needs including Boundaries with Time and Commitments, Mentally Processing Daily Stressors, and Healthy Lifestyle. Implications for practice denote that school leaders need to evaluate the current level of support provided to teachers and assess areas of need to provide professional learning that is purposeful, collaborative, and sustainable. Further research is encouraged to engage in additional conversations via interviews and focus groups about the challenges faced by teachers to better understand their needs during this “new normal”, which is pertinent to stabilizing the teacher workforce as schools face increasing teacher discontentment and teacher attrition, which is even more compounded during this pandemic
Sequencing and functional characterization of a Latrodectus geometricus defensin, Lg-defensin
Get PDFDefensins are small, cysteine-rich, immune related proteins described to be the most widespread family of invertebrate antimicrobial peptides. Presently, there is limited information regarding spider defensins. In this study, a new defensin peptide was described in Latrodectus geometricus, Lg-defensin. The full open reading frame was resolved using RACE and de novo assembly, followed by a bioinformatical analysis and phylogenetic alignment to determine conserved sequence patterns and structural similarities to other defensins. Next, the functionality of Lg-defensin was determined using in vitro RNA interference to assess what impact silencing had on the spider’s ability to control a gram-positive and gram-negative bacterial infection, whose level was determined via qPCR analysis. Results indicated Lg-defensin to be a highly conserved defensin with similar structure and sequence patterns to other related taxa. Additionally, Lg-defensin was found to have higher antibacterial activity towards the gram-positive bacteria in contrast to its effect on gram-negative bacteria. This is the first report regarding the completed characterization of a defensin peptide in L. geometricus and provides a basis for future research regarding Lg-defensin and its clinically relevant capabilities
The Reporter Who lost the War: An In-depth Look at Walter Cronkite\u27s Report on the Tet Offensive and its Long-Term Effects
Get PDFUrbanization Increases Isolation of a Threatened Fish Species in East Texas Streams: A 20-year Perspective
Get PDFWe conducted monthly surveys of fish and in-stream habitat conditions from August 2020 to August 2021 in reaches along Banita Creek and La Nana Creek to investigate ecology and population status of the Sabine shiner (Notropis sabinae) within these streams. On average, Banita Creek had shallow water with low flow, more diverse instream habitats, and lower values of salinity, conductivity, and turbidity compared La Nana Creek. The movements of Sabine shiners were tracked monthly using Visual Implant Elastomer tags. Over a year-long survey, we collected 267 Sabine shiners from Banita Creek and 10 individuals from La Nana Creek. Out of this total, 169 individuals were tagged with a recapture of 98 individuals from a small reach on Banita Creek indicating the potential isolation of this population in this urbanized creek. Given the geographic restriction of this species in east Texas streams and its conservation status, our results have important contributions for management, restoration and conservation implications of the species
