443 research outputs found

    Improving stress coping ability: comparison between the CYP17 genotype Of Ovis Aries and Capra Hircus

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    The ability of animals to adapt to stress is not only an animal health and welfare concern, but also influences reproduction potential and robustness. An important pathway involved in the stress response is the hypothalamic-pituitary-adrenal axis (HPAA) that results in the release of cortisol from the adrenal gland. In this study the cortisol responses of South African Merinos were measured to assess HPAA responsiveness to stress and relate it to behavioural stress responses to flock-isolation. The experiment was structured according to a 2×2 statistical design, with CYP17 genotype (WT1/WT1 vs. WT1/WT2) and selection line (H-line vs. L-line) as factors. Selection line criteria was based on divergent selection for (H-line) or against (L-line) maternal multiple rearing ability, where the H-line generally outperformed the L-line in terms of reproduction, animal welfare and resistance to certain pathogens. The CYP17 genotype is involved in the biosynthesis pathway of cortisol. In the present study the CYP17 genotype showed a significant influence on behavioural stress responses, where three parameters of the flock-isolation test were affected (P<0.05), namely the number of bleats uttered, the urinating frequency and the average distance from a human operator. It is suggested that the CYP17 genotype affects behavioural responses via its effects on cortisol production, and that the SNPs located within the CYP17 genotype may have application in marker-assisted selection of sheep

    The role of Cytochrome P450 17-alpha-Hydroxylase/ 17,20-Lyase (CYP17) in the stress coping ability in a divergently selected Merino sheep population

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    South African Merino sheep were selected divergently from the same base population for their ability to rear multiples. Two distinct populations were formed over a period of more than 20 years of selection. Reproduction (and therefore presumably fitness) in the line selected in the upward direction (H-line) was substantially improved compared to the line selected in the downward direction (L-line). In the present study, it was demonstrated that the H-line was more stresstolerant than the L-line in terms of their glucose and cortisol response when challenged with insulin. Sheep from the breeding program were genotyped according to one of two cytochrome P450 17α-hydroxylase/17-20 lyase (CYP17) alleles, as these genotypes were previously linked to the ability of Angora goats to cope with external stressors. However, no association was found between CYP17 genotype and selection line. The difference in insulin induced stress response between the H- and the L-line can therefore not be attributed to CYP17 genotype

    Expression of DC-SIGN and DC-SIGNRs in placentas of HIV-positive patients

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    Background. Human dendritic cell-specific intracellular adhesion molecule-3 (ICAM3)-grabbing non-integrin (DC-SIGN) is a mannose-binding lectin that initiates interaction between dendritic cells and resting T-lymphocytes. DC-SIGN is highly expressed in placental tissue on dendritic cells and Hofbauer cells, and it is suggested that HIV may become adsorbed to DC-SIGN on Hofbauer cells as part of the mechanism of mother-to-child HIV transmission. A possible mechanism of transfer of the virus from the Hofbauer cells to the fetus is the subsequent adsorption to DC-SIGN-related molecules (DC-SIGNRs), present on immediately adjacent capillary vascular endothelium. However, data on DC-SIGN and DC-SIGNR expression in the placenta are few. Methods. Forty term placentas from HIV-positive mothers and 21 term placentas from HIV-negative mothers underwent immunohistochemistry staining for DC-SIGN and DC-SIGNR expression. Five random sets of 10 villi were assessed, and the average number of positive cells were counted in each case. In addition, where possible, maternal and cord blood viral loads and maternal CD4+ counts were performed in the HIV-positive group only. Results. The median maternal CD4+ count was 377 cells/μl and 27% of participants had undetectable viral loads; the median detectable viral load was 3.72 log. Most (97%) of the cord bloods tested in infants from HIV-positive mothers had lower than detectable viral loads. HIV-positive cases had significantly greater expression of both DC-SIGNRs (median values in HIV-positive cases, 14.5 positive cells/10 villi (pc/10villi), compared with 11 pc/10villi in HIV-negative cases, p=0.020) and DC-SIGN (median value in HIV-positive cases, 26.5 pc/10villi, compared with 23 pc/10villi in HIV-negative cases, p=0.037). DC-SIGNR expression was also noted in Hofbauer cells and decidual macrophages in addition to endothelium (reported currently). There was no difference in expression of DC-SIGN and DC-SIGNRs in patients with or without chorioamnionitis, but there was an inverse relationship between DC-SIGN and DC-SIGNR expression and maternal CD4+ counts in HIV-positive cases. Conclusion. Both DC-SIGN and DC-SIGNR expression were higher in placentas from HIV-positive mothers compared with HIV-negative cases. These lectins may be potential new therapeutic targets for preventing vertical transmission of HIV

    Improving stress coping ability: comparison between the CYP17 genotype Of Ovis Aries and Capra Hircus

    Get PDF
    The ability of animals to adapt to stress is not only an animal health and welfare concern, but also influences reproduction potential and robustness. An important pathway involved in the stress response is the hypothalamic-pituitary-adrenal axis (HPAA) that results in the release of cortisol from the adrenal gland. In this study the cortisol responses of South African Merinos were measured to assess HPAA responsiveness to stress and relate it to behavioural stress responses to flock-isolation. The experiment was structured according to a 2×2 statistical design, with CYP17 genotype (WT1/WT1 vs. WT1/WT2) and selection line (H-line vs. L-line) as factors. Selection line criteria was based on divergent selection for (H-line) or against (L-line) maternal multiple rearing ability, where the H-line generally outperformed the L-line in terms of reproduction, animal welfare and resistance to certain pathogens. The CYP17 genotype is involved in the biosynthesis pathway of cortisol. In the present study the CYP17 genotype showed a significant influence on behavioural stress responses, where three parameters of the flock-isolation test were affected (P<0.05), namely the number of bleats uttered, the urinating frequency and the average distance from a human operator. It is suggested that the CYP17 genotype affects behavioural responses via its effects on cortisol production, and that the SNPs located within the CYP17 genotype may have application in marker-assisted selection of sheep

    The adoption of open access scholarly communication in Tanzanian public universities: some Influencing factors

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    Open access is a means for free availability of scholarly content via the internet. It is an emerging opportunity for wider and unlimited access to scholarly literature. Scholarly communication, through open access journals and self-arching, are the two main approaches of open access publishing. However, this mode of scholarly communication is not widely utilised in developing countries such as Tanzania. This article discusses the factors that influence the adoption of open access for scholarly communication in Tanzanian public universities, based on a study conducted in 2008 using a survey questionnaire. A sample of 544 researchers, selected through stratified random sampling from a population of 1 088 researchers and 69 policymakers at six public universities in Tanzania, provided their views. It was evident from the findings that researchers’ internet usage skills and self-efficacy, social influence, performance expectancy, effort expectancy, and the respondents’ general perceptions about open access were the positive factors likely to facilitate open access adoption. The current poor research conditions and researchers’ low internet self-efficacy (such as inadequate information search skills) were cited as the main hindrances for researchers to use open access outlets to access scholarly content. It is therefore recommended that university policies on scholarly communication should be revised to incorporate the use of open access publishing. Furthermore, universities should accelerate the establishment of institutional repositories, advocacy campaigns and training directed at researchers, policymakers, readers and information managers of scholarly content, and the improvement of internet speed through subscription to more bandwidth, so as to meet the demand from the scholarly communit

    The role of Cytochrome P450 17-alpha-Hydroxylase/ 17,20-Lyase (CYP17) in the stress coping ability in a divergently selected Merino sheep population

    Get PDF
    South African Merino sheep were selected divergently from the same base population for their ability to rear multiples. Two distinct populations were formed over a period of more than 20 years of selection. Reproduction (and therefore presumably fitness) in the line selected in the upward direction (H-line) was substantially improved compared to the line selected in the downward direction (L-line). In the present study, it was demonstrated that the H-line was more stresstolerant than the L-line in terms of their glucose and cortisol response when challenged with insulin. Sheep from the breeding program were genotyped according to one of two cytochrome P450 17α-hydroxylase/17-20 lyase (CYP17) alleles, as these genotypes were previously linked to the ability of Angora goats to cope with external stressors. However, no association was found between CYP17 genotype and selection line. The difference in insulin induced stress response between the H- and the L-line can therefore not be attributed to CYP17 genotype

    Assessment of the genetic diversity of geographical unrelated Microcystis aeruginosa strains using amplified fragment length polymorphisms (AFLPs)

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    Molecular marker analysis is becoming increasingly capable of identifying informative genetic variation. Amplified fragment length polymorphism markers (AFLPs) are among the recent innovations in genetic marker technologies, and provide a greater capacity for genome coverage and more reproducible results than previous technologies. We have investigated the usefulness of AFLP, which is based on the selective amplification of genomic restriction fragments by PCR, to differentiate between geographical unrelated Microcystis strains. In total 23 strains were subjected to the AFLP fingerprinting. After analysis of the data on the basis of the average linkage method, known as the Unweighted Pair Group Method using Arithmetic averages (UPGMA), a dendrogram with four clusters was obtained. Cluster 1 consisted mainly of the NIES strains that originated from Japan, while in cluster 2 the European strains grouped together. The South African strains that originated from the northern part of the country group together in cluster 3, while the strains collected from the central and southern regions group together with the US strains in cluster 4. The study had reveals extensive evidence for the applicability of AFLP in cyanobacterial taxonomy, and furthermore clearly demonstrates the superior discriminative power of AFLP towards the differentiation of geographical unrelated Microcystis aeruginosa strains that belong to the same species, as well as highlighting the potential of this fingerprinting method in evolutionary studies.African Journal of Biotechnology Vol. 4 (5), pp. 389-399, 200

    Improving information use by SMEs in Northern Uganda through information and communication technologies (ICTs)

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    Uganda's economy has great potential. Endowed with significant natural resources, including ample fertile land, regular rainfall, and mineral deposits, it appeared poised for rapid economic growth and development at independence. However, chronic political instability and erratic economic management produced a record of persistent economic decline that left Uganda among the world's poorest and least-developed countries (United States, Bureau of African Affairs 2007). Small and Medium Enterprises (SMEs) have an important role in uplifting the economic standards of the majority of poor people because such enterprises involve little financial investment but much time and effort. The success of SMEs requires investment and use of ICTs, especially the internet, which has become a vital platform for both business information and transactions. Based on the above premise, a study was conducted to establish the ICTs application by SMEs in business transactions in northern Uganda. Using a quantitative descriptive survey design, the study solicited the views of SME managers, information providers and business policy makers in northern Uganda. Both questionnaires and interviews were used as data collection instruments. The aim was to obtain data regarding the ICTs used for business operations, usefulness of different ICTs for business operations, the ICT skills of SMEs business managers, ICTs utilisation for business information access and problems faced in internet utilisation for business and information transactions. This paper reports some of the interesting findings on ICTs utilisation especially the internet in this disadvantaged region of Uganda. Mainly is the fact that SMEs in northern Uganda are lagging behind the trend of applying ICTs to access, use and share pertinent business information. As such they are disadvantage in the current world of e-commerce and web presence. A number of problems that hinder fast-tracking these enterprises into mainstream ICT usage need to be urgently attended to. The study recommends the establishment of integrated ICTs based business information provision strategy that should include: telephone text services, client's based services, interactive business planner, online small business workshops, e-mail services and Talk to Business Information Systems services.Information Scienc

    Simulation of ancestral selection graphs for Monte Carlo integration

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    An ancestral selection graph is a realization of an genealogy-process model which incorporates natural selection. The space of ancestral graphs is a countable union of spaces of unequal dimensions. We give a Markov Chain Monte Carlo algorithm simulating ancestral selection graphs. Output can be used to estimate expectations for functions defined on the space of ancestral graphs

    Social constructions of gender roles, gender-based violence and HIV/AIDS in two communities of the Western Cape, South Africa

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    The links between gender roles, gender-based violence and HIV/AIDS risk are complex and culturally specific. In this qualitative study we investigated how women and men in two black communities in the Western Cape, South Africa, constructed their gender identities and roles, how they understood gender-based violence, and what they believed about the links between gender relations and HIV risk. First we conducted 16 key informant interviews with members of relevant stakeholder organisations. Then we held eight focus group discussions with community members in single-sex groups. Key findings included the perception that although traditional gender roles were still very much in evidence, shifts in power between men and women were occurring. Also, gender-based violence was regarded as a major problem throughout communities, and was seen to be fuelled by unemployment, poverty and alcohol abuse. HIV/AIDS was regarded as particularly a problem of African communities, with strong themes of stigma, discrimination, and especially ‘othering' evident. Developing effective HIV/AIDS interventions in these communities will require tackling the overlapping as well as divergent constructions of gender, gender violence and HIV which emerged in the study. Keywords: gender roles, gender-based violence, HIV/AIDS, South Africa. RÉSUMÉ Les liens entre les rôles de genre, la violence contre les femmes et le risque du VIH/SIDA sont complexes et culturellement particuliers. Dans cette étude qualitative, nous avons examiné: comment des hommes et des femmes ont construit des identités et les rôles de genre dans deux communautés noires du Cap de l'Ouest, en Afrique du Sud, comment ont-ils compris la violence contre les femmes et ce qu'ils croyaient des liens entre les relations de sexes et le risque du VIH. Dans un premier temps, nous avons mené 16 entretiens principaux d'informateurs auprès des membres des organismes dépositaires. Ensuite, nous avons eu huit discussions des groupes de foyer avec des membres de la communauté en deux groupes différents, un pour les femmes un autre pour les hommes. Les résultats de recherche ont inclus la perception que: même si les rôles de genre traditionnels restent toujours évidents, il y a aussi le déplacement de pouvoir entre les hommes et les femmes. De plus, la violence contre les femmes était vue comme un problème majeur à travers les communautés et d'être aggravée par le chômage, la pauvreté et l'abus d'alcool. Le VIH/SIDA était considéré particulièrement comme un problème des communautés africaines avec des thèmes fortes de stigmatisation, de discrimination et surtout le ‘othering' évidents. Le développement des interventions efficaces du VIH/SIDA dans ces communautés va exiger une maîtrise des constructions de genre qui se recouvrent partiellement et qui sont divergentes également, la violence contre les femmes et le VIH qui ont apparu dans cette étude. Mot clés: les rôles de genre, la violence contre les femmes, le VIH/SIDA, l'Afrique du Sud
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