The actinomycetes are gram-positive bacteria that produce more than two-thirds of the known biologically active microbial natural products, including many commercially important antibiotics, anti-cancer agents, other pharmacologically useful agents, animal health products and agrochemicals. The prevailing utilization of antibiotics continues to be the mainstay against microbial infections and a majority ofthe over six thousand antibiotics discovered thus far are from Streptomyces spp. One of the most well-characterized antibiotic biosynthetic pathway is the one involving the biosynthesis of the penicillins, cephalosporins and cephamycins. This pathway involves two initial steps which are common in filamentous fungi, lower eukaryotes and prokaryotes. The penam nucleus of penicillins and the cephem nucleus of both cephamycins andcephalosporins are formed by the condensation of the three precursor amino acids L-a-aminoadipic acid, Lcysteine and L-valine by a mechanism designated as 'non-ribosomal peptide synthesis', which involves activation and condensation of the three component amino acids and epimerization of the L- to D-valine to form a linear acyclic tripeptide called o-(L-a-aminoadipyl)-L-cysteinyl-Dvaline (ACV) by the action of a peptide synthetase. ACV is then cyclized to form isopenicillin N, an intermediate that contains an L-a-aminoadipyl side-chain attached to the penem nucleus (Fig. 1.2) by isopenicilin N synthase (IPNS or Cyclase) and this encompasses the creation of the Beta-lactam and thiazolidine rings. A broad range of ~-lactam producing Streptomyces spp were grown, the DNA extraction procedure optimised and total chromosomal DNA isolated. A bioinformatics analysis of known IPNS gene sequences allowed the synthesis of PCR primers for the iso-penicillin N synthase gene. IPNS genes and lPNS-like genes were successfully amplified from the total DNA of ten strains including two novel thermophilic strains, A. and B. Sequencing was carried out on the genes from S. hygroscopicus, S. tanashiensis and the two thermophiles A and B. This allowed development of the conditions for gene shuffiing of the IPNS gene which was carried out pairwise and resulted in the reconstitution of shuffied genes of the correct size. The resulting mixed gene sequences were cloned into the pTrcHis2-TOPO expression vector and the plasmid DNA screened and assayed for IPNS activity using HPLC which showed ten fold increase in IPNS activity as a result of the shuffiing.

Much scientific and media attention has been devoted to the growing body of research into the genetic correlates of human phenomena. However, many of the resulting reports lead to a deterministic interpretation of the role of genes, and involve fundamental misunderstandings of genetics and heredity. Hence, questions arise regarding the ways in which people make sense of the behavioural genetics research they encounter in everyday life. Furthermore, essentialist accounts are often embedded within popular understanding of politically sensitive topics, such as eugenics, race, and sex, and therefore it is important to examine how people comprehend genetic influences on behaviour. In this dissertation, I review current findings regarding the effects of genetic attributions on beliefs, attitudes, and behaviours in the context of the social world. Particular attention is paid to such effects in the context of gender issues. Specifically, in three studies I examine the effects of exposure to scientific theories concerning human sexuality on attitudes towards and evaluations of men’s dubious sexual behaviors. The results indicate that among men exposure to evolutionary psychology arguments leads to more lenient evaluations and judgments of an array of dubious sexual behaviors, compared with exposure to social constructivist arguments. It also seems that men implicitly hold nativist perceptions with regards to male sexuality and promiscuity. The findings were less conclusive among women, with some indication that women are less affected by such exposure as well as less likely to naturally hold a nativist perspective in the context of human sexuality. This empirical research has direct implications for previously suggested intervention programs and adds to the incurrent resurgence of interest in the effects of genetic theories. Finally, I identify areas where further exploration is needed, suggest potential solutions for specific problems, and evaluate related individual and social implications. / Arts, Faculty of / Psychology, Department of / Graduate

No description available.

Submitted by Pedro Barros (pedro.silvabarros@ufpe.br) on 2018-09-21T22:13:13Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Joana Braga de Moraes Marques Ferreira.pdf: 5193351 bytes, checksum: 0e24ea46d41e7220625b8f65daf73891 (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-09-24T17:34:42Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Joana Braga de Moraes Marques Ferreira.pdf: 5193351 bytes, checksum: 0e24ea46d41e7220625b8f65daf73891 (MD5) / Made available in DSpace on 2018-09-24T17:34:42Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE Joana Braga de Moraes Marques Ferreira.pdf: 5193351 bytes, checksum: 0e24ea46d41e7220625b8f65daf73891 (MD5) Previous issue date: 2016-03-10 / FACEPE / Primary brain calcification (PBC), also known as idiopathic brain calcification or Fahr's disease, is a rare neurological condition that is characterized by calcium phosphate deposits in the basal ganglia and adjacent areas, movement disorders, headache and neuropsychiatric symptoms. It presents autosomic dominant inheritance and it is associated with two inorganic phosphate transporter coding genes: SLC20A2 and XPR1. Two other genes related to the blood-brain barrier maintenance and integrity are also linked to PBC, the platelet-derived growth factor-β and its receptor (PDGFB and PDGFRB), although their roles in the formation mechanism of the calcifications is not clear yet. For this study, besides the four genes above mentioned, other members of the platelet-derived grown factor family (PDGFA, PDGFRA, PDGFC and PDGFD) have also been selected as candidate genes, for which new primer pairs were designed. All genes above were screened for new variants by Sanger sequencing in fifteen Brazilian unrelated patients with brain calcifications. Sequence in silico analysis was performed using CLC Main Workbench 6.9 software and online tools available in NCBI and GOLDENPATH platforms, resulting in the identification of the first de novo SLC20A2 mutation in a patient diagnosed with PBC (NM_006749.4:c.1158C>G; NP_006740.1:p.Y386*). SLC20A2 is to-date the main gene associated with PBC, with affecting-variants observed in ~50% cases. In order to find SLC20A2 deletions and/or duplications not detected by sequencing, all Brazilian probands were screened by QMPSF (Quantitative Multiplex PCR of Short fluorescent Fragments) and a duplication of the terminal exon was found in a patient with brain calcifications and hyperparatiroidism. Simultaneously, twenty-four French unrelated patients with PBC were also analyzed by QMPSF and partial SLC20A2 deletions were detected in four patients: two with deletion of the exon 2, where the start codon is located; one with deletion of the exon 4; and one with deletion of exons 4 and 5. These results reinforce SLC20A2 role as the main gene associated to PBC, as well as demonstrate that copy number variation analyses, even when revealing only partial deletions or duplications of a gene, are complementary to sequencing and work side by side in the search of genetic variations involved in this disease. / Introdução: A calcificação cerebral primária (CCP), também conhecida como calcificação idiopática dos núcleos da base ou doença de Fahr, é uma condição neurológica caracterizada por depósitos de fosfato de cálcio dos núcleos da base e região de entorno, parkinsonismo e sintomas neuropsiquiátricos. Apresenta herança autossômica dominante e é associada a dois genes codificantes de transportadores de fosfato inorgânico: o SLC20A2 e o XPR1. Dois outros genes relacionados à manutenção e à integridade da barreira hemato-encefálica, o fator de crescimento plaquetário B e seu receptor (PDGFB e PDGFRB), também foram associados à CCP, embora seus papeis no mecanismo de formação das calcificações ainda não estejam claros. Materiais e Métodos: Além dos quatro genes acima, foram selecionados como candidatos outros genes da família dos fatores de crescimento plaquetário (PDGFA, PDGFRA, PDGFC e PDGFD) e das protocaderinas (PCDH12), para os quais foram confeccionados pares de primers utilizados no seu sequenciamento e para análise de variação de número de cópia. Resultados e Discussão: Quinze famílias brasileiras com CCP foram triadas para novas variantes nos genes candidatos por sequenciamento. A análise in silico do sequenciamento foi feita através do software CLC Combined Workbench versão 6.9 e das ferramentas disponíveis nas plataformas online do NCBI e do GOLDENPATH. A partir dessa análise, foi identificada em um probando a primeira mutação de novo do SLC20A2, o principal gene associado a CCP (NM_006749.4:c.1158C>G; NP_006740.1:p.Y386*). A fim de encontrar deleções e/ou duplicações do SLC20A2 não detectadas por sequenciamento, todos os probandos brasileiros com calcificações cerebrais foram triados através da técnica de QMPSF (do inglês, Quantitative Multiplex PCR of Short fluorescent Fragments). Foi encontrada uma duplicação do exon terminal do mesmo gene em um paciente brasileiro com calcificações cerebrais e hiperparatireoidismo. Simultaneamente, foram identificadas deleções parciais no mesmo gene em quatro famílias francesas com CCP. Conclusões: Esses resultados reafirmam o SLC20A2 como o principal gene associado a CCP, bem como demonstram que análises de variação de número de cópia (CNV), ainda que parciais, são complementares ao sequenciamento na busca por variantes genéticas relacionadas a esta doença.

Objetivo: Analizar los estudios observacionales para determinar la relación entre los genes involucrados en el metabolismo de los lípidos (ABCA7, SORL1 y APOE) y el desarrollo de la Enfermedad de Alzheimer de Inicio Precoz (EAIP) en pacientes menores de 65 años. Diseño: Se realizará una revisión sistemática y metaanálisis, de estudios observacionales analíticos, de acuerdo con las pautas del Preferred reporting items for systematic review and meta-analysis

Bacillus cereus is a Gram-positive, spore-forming bacterium that is frequently identified as the causative agent of food-borne diseases and is also implicated in food spoilage of especially dairy products. The capacity of B. cereus to form biofilms on different substrata is of great concern in the food industry. Not only does biofilm formation cause economic loss by equipment failure, but contamination of food products via biofilm cells also raises safety concerns. Bacterial biofilms have been defined as structmed multicellular communities that form through a complex developmental process. In contrast to Gram-negative bacteria, biofilm formation by Gram-positive bacteria has only recently been examined. Relatively few genes have been identified that are required for these bacteria to form biofilms and little is known about how they coordinate biofilm formation. In order to contribute to the advancement of knowledge regarding the process of biofilm formation in Gram-positive bacteria, the aim of this investigation was essentially to identify and characterize genes involved in B. cereus biofilm formation. To investigate. B. cereus ATCC 14579 was subjected to transposon mutagenesis with the Tn917-LTVI transposon. Screening of a collection of3 500 insertional mutants for the ability to form biofilms at the solid-liquid-air interface of glass surfaces led to the identification of eight biofilm-impaired mutants. Each of the mutants contained a single transposon insertion, and no significant differences were observed in the planktonic growth rate between the B. cereus wild-type and biofilm-impaired mutant strains. The chromosomal transposon insertion in three of the mutants mapped to genes involved in purine biosynthesis (pur A, purC and purL), while the transposon insertion in two other mutants mapped to the ftsE gene and to the promoter region of the motA gene, respectively. In one of the mutants the transposon was located in the intergenic region between two divergently transcribed genes, which encodes a murein hydrolase exporter and nucleoside hydrolase, respectively. In the final two biofilmimpaired mutants the transposon was respectively mapped to genes encoding a putative membrane spanning protein and a putative protein of unknown function. Results obtained by quantitative real-time PCR assays indicated that expression of each of the identified B. cereus ATCC 14579 genes, with the exception of the motA gene, was up-regulated in the biofilm population. In the case of motA, expression of the gene was down-regulated 3.2-fold in the biofilm population and results obtained during the course of this investigation indicated that motility, rather than the presence of flagella, is required for B. cereus biofilm formation. Although this result is in agreement with that reported previously for B. subtilis, none of the other genes identified in this investigation have previously been implicated in biofilm formation by Gram-positive bacteria. / Dissertation (MSc)--University of Pretoria, 2010. / Microbiology and Plant Pathology / unrestricted

No description available.

No description available.

Sociability is defined as the tendency of conspecifics to do non-aggressive activities with each other. In many species, being in a group increases fitness, making it highly relevant to understand. Fruit flies (Drosophila melanogaster) are an ideal model system to study sociability because of their complex social lives. A previous artificial selection experiment created evolved lineages of low and high sociability. Extraction, sequencing, and follow up genomic analyses of these lineages allowed us to identify candidate sociability genes. However, a causal link between genes and sociability has yet to be identified. The goal of this thesis was to functionally validate the effect of these genes. We used RNA Interference (RNAi) to knock down genes and measure subsequent changes in sociability between knockdown and control flies. Our predictions were based on the differential expression of each gene: We predicted that genes with lower expression in the low sociability lineages compared to the control lineage would have lower sociability scores than controls, and vice versa. We used circular 3D printed circular arenas like the ones in Scott et al., (2022) to measure sociability. We successfully verified 10 out of the 20 genes we tested. Sec5, CG13197, Ir94D, and Est-P altered sociability in the predicted direction. We also found that thoc5, CG8329, DJ-1, Net-A, FBgn0033353, and ppk28 also affected sociability, but in the opposite than predicted direction. Future work entails validating a second set of candidate genes that were identified based on population genomic work, investigating other social behaviours in some verified genes, and testing orthologs of verified genes in mice to understand sociability from an evolutionary perspective across various species. / Thesis / Master of Science (MSc) / Sociability is an individual’s tendency to do friendly activities with others. The genetic basis is not clear. To address this gap, we silenced genes that were identified in previous work. We predicted that silencing these genes will alter sociability and used circular arenas to measure it. We found that 10 out of 20 genes affected sociability. Future research includes validating a second set of genes, investigating other social behaviours for verified genes, and to test verified genes in mice.

An 18.5-kb human DNA segment was selected from a human XCharon-4A library by hybridization to mammalian valine tRNAiAc and found to encompass a cluster of three tRNA genes. Two valine tRNA genes with anticodons of AAC and CAC, encoding the major and minor cytoplasmic valine tRNA isoacceptors, respectively, and a lysine tRNAcuu gene were identified by Southern blot hybridization and DNA sequence analysis of a 7.1-kb region of the human DNA insert. At least nine Alu family members were found interspersed throughout the human DNA fragment. The tRNA genes are accurately transcribed by RNA polymerase III in a HeLa cell extract, since the RNase Ti fingerprints of the mature-sized tRNA transcription products are consistent with the DNA sequences of the structural genes. Three members of the chimpanzee triosephosphate isomerase (TPI) gene family, the functional transcription unit and two processed pseudogenes, were characterized by genomic blotting and DNA sequence analysis. The bona fide TPI gene spans 3.5 kb with seven exons and six introns, and is the first complete hominoid TPI gene sequenced. The gene exhibits a very high identity with the human and rhesus TPI genes. In particular, the polypeptides of 248 amino acids encoded by the chimpanzee and human TPI genes are identical, although the two coding regions differ in the third codon wobble positions for five amino acids. An Alu member occurs upstream from one of the processed pseudogenes, whereas an isolated endogenous retroviral long terminal repeat (HERV-K) occurs within the structural region of the other processed pseudogene. The ages of the processed pseudogenes were estimated to be 2.6 and 10.4 million years, implying that one was inserted into the genome before the divergence of the chimpanzee and human lineages, and the other inserted into the chimpanzee genome after the divergence.