Resveratrol prevents alcohol-induced cognitive deficits and brain damage by blocking inflammatory signaling and cell death cascade in neonatal rat brain

Human prenatal ethanol exposure that occurs during a period of increased synaptogenesis known as the 'brain growth spurt' has been associated with significant impairments in attention, learning and memory. Recent studies have shown that administration of ethanol to infant rats during the synaptogenesis period (first 2 weeks after birth) triggers extensive apoptotic neurodegeneration throughout many regions of the developing brain and results in cognitive dysfunctions as the animal matures. The present study was designed with an aim to investigate the effect of resveratrol, a polyphenolic phytoalexin (trans-3,5,4-trihydroxy stilbene) present in red wine on alcohol-induced cognitive deficits and neuronal apoptosis in rat pups postnatally exposed to ethanol. Pups were administered ethanol (5 g/kg, 12% v/v) by intragastric intubation on postnatal days 7, 8, and 9. Ethanol-exposed pups showed impaired memory performance in both Morris water maze elevated plus maze task recorded by using computer tracking with EthoVision software. Behavioral deficit in ethanol-exposed pups was associated with enhanced acetylcholinesterase activity, increased oxidative-nitrosative stress, cytokine (TNF-α, IL-1β and TGF-β), nuclear factor kappa beta and caspase 3 levels in both cerebral cortex and hippocampus. Chronic treatment with resveratrol (10 and 20 mg/kg) significantly attenuated all the behavioral, biochemical and molecular changes in different brain regions of ethanol administered pups. The major finding of the study is that resveratrol blocks activation of nuclear factor kappa beta pathway and apoptotic signaling and prevents cognitive deficits in rats postnatally exposed to ethanol.     

The Erwin equation of biodiversity: From little steps to quantum leaps in the discovery of tropical insect diversity

Almost 40 years ago, Terry L. Erwin published a seemingly audacious proposition: There may be as many as 30 million species of insects in the world. Here, we translate Erwin's verbal argument into a diversity-ratio model—the Erwin Equation of Biodiversity—and discuss how it has inspired other biodiversity estimates. We categorize, describe the assumptions for, and summarize the most commonly used methods for calculating estimates of global biodiversity. Subsequent diversity-ratio extrapolations have incorporated parameters representing empirical insect specialization ratios, and how insect specialization changes at different spatial scales. Other approaches include macroecological diversity models and diversity curves. For many insect groups with poorly known taxonomies, diversity estimates are based on the opinions of taxonomic experts. We illustrate our current understanding of insect diversity by focusing on the six most speciose insect orders worldwide. For each order, we compiled estimates of the (a) maximum estimated number of species, (b) minimum estimated number of species, and (c) number of currently described species. By integrating these approaches and considering new information, we believe an estimate of 5.5 million species of insects in the world is much too low. New molecular methodologies (e.g., metabarcoding and NGS studies) are revealing daunting numbers of cryptic and previously undescribed species, at the same time increasing our precision but also uncertainty about present estimates. Not until technologies advance and sampling become more comprehensive, especially of tropical biotas, will we be able to make robust estimates of the total number of insect species on Earth.     

Leveraging remote learning during the Covid‐19 pandemic to enhance student understanding of biodiversity

We evaluated whether individual nature‐based ecological (NBE) study used in tandem with group collaboration enhanced undergraduate student understanding of ecological concepts and pro‐environmental perceptions. In response to the Covid‐19 pandemic, we developed a multiweek unit on the latitude diversity gradient (LDG) for fully online instruction that leveraged the unique situation of students learning in disparate geographic locations. Student understanding of the LDG and pro‐environmental perceptions were assessed with surveys administered both pre‐ and post‐activity in an introductory‐level biology laboratory course. Student understanding of the geographic location where biodiversity is the highest was high prior to the start of the laboratory unit and exhibited only a small improvement after the unit. In contrast, students’ higher order thinking around the LDG was enhanced by the lab activity. Student environmental perceptions shifted toward ecocentric views and away from anthropocentric views after the laboratory unit. The greatest gains in ecological understanding and shifts toward ecocentric viewpoints occurred in the group of students who visited their field sites most often. Our results provide further evidence as to the value of NBE for the introductory biology laboratory, even in an online learning setting. The lab unit described in this study provides a potential approach to teaching ecology in an online format that could easily be adapted to fit the needs of a particular curriculum.     

Conservation of key members in the course of the evolution of the insulin signaling pathway

Our understanding of the evolution of the insulin signaling pathway (ISP) is still incomplete. One intriguing unanswered question is the explanation of the emergence of the glucostatic role of insulin in mammals. To find out whether this is due to the development of new sets of signaling transduction elements in these organisms, or to the establishment of new interactions between pre-existing proteins, we rebuilt putative orthologous ISPs in 17 eukaryotic organisms. Then, we computed the conservation of orthologous ISPs at different levels, from sequence similarity of orthologous proteins to co-evolution of interacting domains. We found that the emergence of glucostatic role in mammals can neither be explained by the development of new sets of signaling elements, nor by the establishment of new interactions between pre-existing proteins. The comparison of orthologous IRS molecules indicates that only in mammals have they acquired their complete functionality as efficient recruiters of effector sub-pathways.     

小麦耐盐种质遗传多样性的RAPD分析

选用２２个引物对２４份小麦耐盐种质进行ＲＡＰＤ分析,共产生２００条扩增片段,多态性片段数为１７２条,扩增片段的多态性百分率为８６％,利用ＮＹＳＴＳ软件根据Ｊａｃｃａｒｄ系统分析ＲＡＰＤ结果,并按ＵＰＧＭＡ类平均法进行聚类。２４份材料相似系数在０．２１￣０．９７之间,其中含有多枝赖草、黑麦和偃麦草等外源染色体的多１７４、ＷＲ８３０和南前１２７被分别在３个独立的组,多１７４和南前１２７的亲关系最远,相     

Evaluation of a DNA pooled-sampling strategy for estimating the RFLP diversity of maize populations

Molecular characterization by means of RFLPs of large sets of populations is presently limited by experimental costs. In order to reduce costs, we have evaluated a method based on the RFLP analysis of balanced bulks of DNA from several individuals. The precision of this approach for estimating allele frequencies within each population was investigated using (i) DNA extracted from controlled bulks of leaf tissues of maize inbred lines, (ii) data obtained from individual analyses of 10 maize populations. Both approaches showed that allele frequencies can generally be estimated with a high precision (coefficients of determination up to 0.99 for some probe-enzyme combinations assayed), relative to the variation in allele frequencies observed among maize populations. Although further efforts are needed to define a set of probe-enzyme combinations that can be routinely image processed, these results, and preliminary results from a 65 maize populations project, suggest that this approach could provide highly informative data for large sets of populations, and at relatively low costs.     

Evidence for specificity of cultivable bacteria associated with arbuscular mycorrhizal fungal spores

Bacteria associated with arbuscular mycorrhizal (AM) fungal spores may play functional roles in interactions between AM fungi, plant hosts and defence against plant pathogens. To study AM fungal spore-associated bacteria (AMB) with regard to diversity, source effects (AM fungal species, plant host) and antagonistic properties, we isolated AMB from surface-decontaminated spores of Glomus intraradices and Glomus mosseae extracted from field rhizospheres of Festuca ovina and Leucanthemum vulgare. Analysis of 385 AMB was carried out by fatty acid methyl ester (FAME) profile analysis, and some also identified using 16S rRNA gene sequence analysis. The AMB were tested for capacity to inhibit growth in vitro of Rhizoctonia solani and production of fluorescent siderophores. Half of the AMB isolates could be identified to species (similarity index 0.6) within 16 genera and 36 species. AMB were most abundant in the genera Arthrobacter and Pseudomonas and in a cluster of unidentified isolates related to Stenotrophomonas. The AMB composition was affected by AM fungal species and to some extent by plant species. The occurrence of antagonistic isolates depended on AM fungal species, but not plant host, and originated from G. intraradices spores. AM fungal spores appear to host certain sets of AMB, of which some can contribute to resistance by AM fungi against plant pathogens.     

Detecting DNA polymorphism and genetic diversity in Lentil (Lens culinaris Medik.) germplasm: comparison of ISSR and DAMD marker

Genetic diversity and interrelationships among 31 lentil genotypes were evaluated using 10 Inter-Simple Sequence Repeat (ISSR) and 10 directed amplification of minisatellite DNA region (DAMD) primers. A total of 43 and 48 polymorphic bands were amplified by ISSR and DAMD markers, respectively. Average polymorphism information content (PIC) for ISSR and DAMD markers were 0.37 and 0.41, respectively. All 31 lentil genotypes could be distinguished by ISSR markers into three groups and by DAMD markers into two groups. Various molecular markers show a different efficiency for evaluating DNA polymorphism in lentil and indicate that the patterns of variation are clearly influenced by the genetic marker used. Comparatively, the genetic diversity of examined lentil genotypes by two different marker techniques (ISSR and DAMD) was high and indicated that ISSR and DAMD are effective and promising marker systems for fingerprinting in lentil and give useful information on its genetic relationships.     

Development of simple sequence repeat (SSR) markers for the assessment of gene flow and genetic diversity in pigeonpea (Cajanus cajan)

Pigeonpea (Cajanus cajan) is an important subsistence crop in India where traditional landraces and improved hybrids are grown alongside each other. Gene flow may result in genetic erosion of these landraces and their wild relatives, whilst transgene escape from future genetically engineered varieties is another potential hazard. To assess the impact of these factors gene flow needs to be measured. A set of 10 simple sequence repeat markers have been developed, which exhibit polymorphism across a range of pigeonpea varieties. Use of these markers also offers an efficient system for the assessment of genetic diversity within populations of pigeonpea.