Evaluation of the genetic diversity of Malawian pigeonpea using simple sequence repeats markers

Pigeonpea (Cajanus cajan (L.) Millsp.) is a drought tolerant legume of the Fabaceae family in the order Fabales and the only cultivated species in the genus Cajanus. It is mainly cultivated in the semi-arid tropics of Asia and Oceania, Africa and America. In Malawi, one of the top producers of pigeonpea in Africa, it is grown by small scale farmers as a source of food and income and for soil improvement in intercropping systems. However, varietal contamination due to natural outcrossing causes significant yield losses for farmers. In this study, 48 polymorphic SSR markers were used to assess diversity in all pigeonpea varieties cultivated in Malawi with the aim of developing a genetic fingerprint to distinguish the released varieties. SSR alleles were separated by capillary electrophoresis on an ABI 3700 automated sequencer and allele sizes determined using GeneMapper 4.0 software. Allelic data was analysed with PowerMarker. A total of 212 alleles were revealed averaging 5.58 alleles per marker with a maximum number of 14 alleles produced by CCttc019 (Marker 40). Polymorphic information content (PIC) ranged from 0.03 to 0.89 with an average of 0.30. DARwin software was used to generate a neighbour-joining tree that displayed three major clusters with two sub clusters in Cluster I. The released varieties were scattered across all the clusters observed, indicating that they generally represent the genetic diversity available in Malawi, although it was observed that there is substantial variation that can still be exploited through further breeding. Screening of the allelic data associated with five popular pigeonpea varieties for which a DNA fingerprint was to be developed, revealed 6 markers – CCB1 (Marker 1), CCB7 (Marker 2), Ccac035 (Marker 7), CCttc003 (Marker 15), Ccac026 (Marker 37) and CCttc019 (Marker 40)– which gave unique allelic profiles for each of the five varieties. With further tests needed for its robustness, this genetic fingerprint can be used for seed certification to ensure only genetically pure seeds are delivered to Malawi farmers.Agriculture and  Animal HealthM. Sc. (Agriculture

Identification of groundnut (Arachis hypogaea) SSR markers suitable for multiple resistance traits QTL mapping in African germplasm

AbstractBackgroundThis study aimed to identify and select informative Simple Sequence Repeat (SSR) markers that may be linked to resistance to important groundnut diseases such as Early Leaf Spot, Groundnut Rosette Disease, rust and aflatoxin contamination. To this end, 799 markers were screened across 16 farmer preferred and other cultivated African groundnut varieties that are routinely used in groundnut improvement, some with known resistance traits.ResultsThe SSR markers amplified 817 loci and were graded on a scale of 1 to 4 according to successful amplification and ease of scoring of amplified alleles. Of these, 376 markers exhibited Polymorphic Information Content (PIC) values ranging from 0.06 to 0.86, with 1476 alleles detected at an average of 3.7 alleles per locus. The remaining 423 markers were either monomorphic or did not work well. The best performing polymorphic markers were subsequently used to construct a dissimilarity matrix that indicated the relatedness of the varieties in order to aid selection of appropriately diverse parents for groundnut improvement. The closest related varieties were MGV5 and ICGV-SM 90704 and most distant were Chalimbana and 47–10. The mean dissimilarity value was 0.51, ranging from 0.34 to 0.66.DiscussionOf the 376 informative markers identified in this study, 139 (37%) have previously been mapped to the Arachis genome and can now be employed in Quantitative Trait Loci (QTL) mapping and the additional 237 markers identified can be used to improve the efficiency of introgression of resistance to multiple important biotic constraints into farmer-preferred varieties of Sub-Saharan Africa

Neurogenomic Evidence for a Shared Mechanism of the Antidepressant Effects of Exercise and Chronic Fluoxetine in Mice

Several different interventions improve depressed mood, including medication and environmental factors such as regular physical exercise. The molecular pathways underlying these effects are still not fully understood. In this study, we sought to identify shared mechanisms underlying antidepressant interventions. We studied three groups of mice: mice treated with a widely used antidepressant drug – fluoxetine, mice engaged in voluntary exercise, and mice living in an enriched environment. The hippocampi of treated mice were investigated at the molecular and cellular levels. Mice treated with fluoxetine and mice who exercised daily showed, not only similar antidepressant behavior, but also similar changes in gene expression and hippocampal neurons. These changes were not observed in mice with environmental enrichment. An increase in neurogenesis and dendritic spine density was observed following four weeks of fluoxetine treatment and voluntary exercise. A weighted gene co-expression network analysis revealed four different modules of co-expressed genes that were correlated with the antidepressant effect. This network analysis enabled us to identify genes involved in the molecular pathways underlying the effects of fluoxetine and exercise. The existence of both neuronal and gene expression changes common to antidepressant drug and exercise suggests a shared mechanism underlying their effect. Further studies of these findings may be used to uncover the molecular mechanisms of depression, and to identify new avenues of therapy

Improved Learning and Memory in Aged Mice Deficient in Amyloid β-Degrading Neutral Endopeptidase

BACKGROUND: Neutral endopeptidase, also known as neprilysin and abbreviated NEP, is considered to be one of the key enzymes in initial human amyloid-beta (Abeta) degradation. The aim of our study was to explore the impact of NEP deficiency on the initial development of dementia-like symptoms in mice. METHODOLOGY/PRINCIPAL FINDINGS: We found that while endogenous Abeta concentrations were elevated in the brains of NEP-knockout mice at all investigated age groups, immunohistochemical analysis using monoclonal antibodies did not detect any Abeta deposits even in old NEP knockout mice. Surprisingly, tests of learning and memory revealed that the ability to learn was not reduced in old NEP-deficient mice but instead had significantly improved, and sustained learning and memory in the aged mice was congruent with improved long-term potentiation (LTP) in brain slices of the hippocampus and lateral amygdala. Our data suggests a beneficial effect of pharmacological inhibition of cerebral NEP on learning and memory in mice due to the accumulation of peptides other than Abeta degradable by NEP. By conducting degradation studies and peptide measurements in the brain of both genotypes, we identified two neuropeptide candidates, glucagon-like peptide 1 and galanin, as first potential candidates to be involved in the improved learning in aged NEP-deficient mice. CONCLUSIONS/SIGNIFICANCE: Thus, the existence of peptides targeted by NEP that improve learning and memory in older individuals may represent a promising avenue for the treatment of neurodegenerative diseases

Literature Mining for the Discovery of Hidden Connections between Drugs, Genes and Diseases

The scientific literature represents a rich source for retrieval of knowledge on associations between biomedical concepts such as genes, diseases and cellular processes. A commonly used method to establish relationships between biomedical concepts from literature is co-occurrence. Apart from its use in knowledge retrieval, the co-occurrence method is also well-suited to discover new, hidden relationships between biomedical concepts following a simple ABC-principle, in which A and C have no direct relationship, but are connected via shared B-intermediates. In this paper we describe CoPub Discovery, a tool that mines the literature for new relationships between biomedical concepts. Statistical analysis using ROC curves showed that CoPub Discovery performed well over a wide range of settings and keyword thesauri. We subsequently used CoPub Discovery to search for new relationships between genes, drugs, pathways and diseases. Several of the newly found relationships were validated using independent literature sources. In addition, new predicted relationships between compounds and cell proliferation were validated and confirmed experimentally in an in vitro cell proliferation assay. The results show that CoPub Discovery is able to identify novel associations between genes, drugs, pathways and diseases that have a high probability of being biologically valid. This makes CoPub Discovery a useful tool to unravel the mechanisms behind disease, to find novel drug targets, or to find novel applications for existing drugs

Resolving the neural circuits of anxiety

Although anxiety disorders represent a major societal problem demanding new therapeutic targets, these efforts have languished in the absence of a mechanistic understanding of this subjective emotional state. While it is impossible to know with certainty the subjective experience of a rodent, rodent models hold promise in dissecting well-conserved limbic circuits. The application of modern approaches in neuroscience has already begun to unmask the neural circuit intricacies underlying anxiety by allowing direct examination of hypotheses drawn from existing psychological concepts. This information points toward an updated conceptual model for what neural circuit perturbations could give rise to pathological anxiety and thereby provides a roadmap for future therapeutic development.National Institute of Diabetes and Digestive and Kidney Diseases (U.S.) (NIH Director’s New Innovator Award DP2-DK-102256-01)National Institute of Mental Health (U.S.) (NIH) R01-MH102441-01)JPB Foundatio

Impact of the Internet on Tourism and Hospitality in Kenya

This thesis gives an insight into the importance of the use of the Internet in tourism and hospitality industries in Kenya. The aim of this thesis was to find out the impacts of the Internet in tourism and hospitality industries and the advantages and disadvantages of the Internet use in tourism and hospitality. The authors’ focus was on hotel and tour companies. The theoretical framework of the thesis includes Internet marketing, business-to-business (B2B) internet marketing, business to consumer (B2C) internet marketing, customer relationship management (CRM) and marketing mix. The aim of this study was to find out how the selected hotel and tour companies use the Internet for bookings and reservations and how tourists are able to make prior bookings and reservations. For the findings, qualitative and quantitative research approaches were used. Questionnaires were used to gather information, which the authors analyzed in the end. The results show that the selected hotel and tour companies in Kenya operate by using the Internet daily for bookings and reservations. It was also found out that domestic and international tourists prefer to use the Internet for their travelling arrangements. Most of the international tourists of this survey were from Europe and most of them had visited Kenya before. The results from the survey indicate that most respondents prefer the Internet to telephone bookings

Effects of some 5-hydroxytryptamine and related ligands in anxiety models

Drugs acting at 5-HT receptors were evaluated on three animal models of anxiety. On the elevated X-maze test the majority of 5-HT1 agonists were found to be anxiogenic. However, ipsapirone was anxiolytic and buspirone and gepirone were inactive. The 5-HT2 agonist DOI and the 5-HT2 antagonist ritanserin were anxiolytic while ICI 169,369, a 5-HT2 antagonist was inactive. All 5-HT3 antagonists tested were inactive in this test, while the indirect serotomimetics zimeldine and fenfluramine were anxiogenic. Neither beta-adrenoceptor agonists nor antagonists had reproducible effects on anxiety in this model. Combined beta-1/beta-2 adrenoceptor antagonists reversed the anxiogenic effects of 8-OH-DPAT while selective beta-1 or beta-2 antagonists did not. On the social interaction model the 5-HT1 agonists 8-OH-DPAT, RU 24969 and 5-MeODMT were anxiogenic and ipsapirone was anxiolytic. The 5-HT2 agonist DOI and the beta-adrenoceptor- and 5-HT- antagonist pindolol were anxiolytic, while the 5-HT2 and 5-HT3 antagonists were inactive. In the marble burying test, the 5-HT upake inhibitors zimeldine, fluvoxamine, indalpine and citalopram, the 5-HT1B/5-HT1C agonists mCPP and TFMPP and the 5-HT2/5-HT1C agonist DOI reduced marble burying without affecting locomotor activity. 5-HT1A agonists and the 5-HT2 and 5-HT3 antagonists were without effect. Lesions of the dorsal raphe nucleus reversed the anxiogenic effects of 8-OH-DPAT in the X-maze model. The implication of these results for the understanding of the pharmacology of 5-HT in anxiety is discussed

Reasons for Teenagers School Dropout from Occupational Studies in Europe

This study is basically a literature review research, that addresses the growing number of teenage drop out across Europe, which clarify the reasons for early school leaving in occupational education. Besides, the study introduces Attention Deficit Hyperactivity Disorder (ADHD) as the major mental disorder factor that leads to early school leaving. The literature review section deeply describes the reasons based on the key terms affected by this study, these are; dropout, adolescence, cognitive conception, occupational studies, ADHD and its causes, effects and impact on school dropout. As a result, this literature review seeks to answer the research questions; What are the causes of adolescent school drop across Europe? What are the effects of school dropout to society? This study has used a descriptive literature review method. The data gathering method involved collecting reliable and academic sources such as Google scholar, Ebsco, Pubmed, Cinahl and science direct. Data was collected based on the topic, language, key concepts and the year of publication. Critical appraisal of data has been done on all the selected articles, before using the inductive approach of the content analysis. The data analysis focused on the extent of reasons for teenagers drop out from occupation studies in Europe. The data analysis critically focused on the teenager’s occupation drop out in Europe and stakeholder’s participation as the major areas of answering the research questions. The study found that reasons for school drop include school poor performance, absenteeism, sickness, school administration difficulties, family setbacks example low income, domestic violence and grade repetition. Although school dropout is strongly related to family-level factors, siblings with poor health tended to have reduced opportunity to complete high school compared to healthy siblings