1,751 research outputs found

    Climate Change and Crop Vulnerability in Nigeria

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    In Nigeria, food insecurity remains problematic due to dislocations in the agricultural productivity pathways. Food preferences and utilization patterns are skewed in favor of crop-based staples, which availability in quantity and quality, depend on the aggregate crop output. Unfavorable environmental conditions such as caused by climate change would create some level of vulnerability of the crops and thus have implication on food security. Two components of the Agricultural Value Chain, production and storage, appear to be most responsive to changes in environments with production being the most vulnerable since all the activities involved in the process of production occur in the fields and are weather -dependent. Climate change – directed irregularities or deviation from the normal seasonal patterns such as onset and duration of wet and dry periods, short and prolonged dry spells clearly manifest in various levels of crop vulnerability. It would therefore appear that a sustainable crop-based agricultural system can only be achieved where crop vulnerability is considerably minimized. If climate change effects can be incorporated in the design and implementation of national development programs right away, it will help to reduce vulnerability, stabilize food production and better secure livelihoods. The ecosystem approach with crop rotations, bioorganic fertilizers (e.g., from legumes) and biological pest controls, improves soil health and water retention, increases fertile top soil, reduces soil erosion and maintains productivity over the long term.Key words: vulnerability, climate change, crop productivity

    Teachers’ Attitude and Competence Towards the use Of ICT Resources: A Case Study Of University Of Agriculture Lecturers, Abeokuta Ogun State, Nigeria

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    The study is on teachers’ attitude and competency towards the use of ICT resources in their lectures.The population of the study were lecturers at the federal university of agriculture, Abeokuta. Questionnaire and observation were instruments used to gather data from the respondents. The findings revealed that majority of the lecturers have positive attitude and competency towards the use of ICT resources in their lectures, and the use of ICT in instruction enhance academic performance of students. The study concludes by recommending that university administration should provide more training in the area of ICT to its staff and improve on regular and uninterrupted power supply to the campus

    Molecular Characterization of Alkaline Phosphatase and PLAP in the Germinal Epithelium of Pb and Se+Zn Treated Adult Sprague Dawley Rats

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    Aim: The role of alkaline phosphatase in cell metabolism and regulation is essential and cuts across cell proliferation, division, cell death, membrane transport and DNA cleavage. This study addresses the role and importance of alkaline phosphates (ALP) and Placenta Alkaline phosphatase (PLAP) in the cells of germinal epithelium of male Rat testes following induced lead (Pb) toxicity and rejuvenation by Selenium (Se) and Zinc (Zn) treatment. Method:Adult Sprague-Dawley Rats (males) were divided into 4 groups of 15 animals each and were treated as thus; Group 1: Normal saline and serves as the control, Group 2: 100 mg/Kg BW of Pb only, Group 3: 100 mg/Kg BW of Pb and 2.25 mg/Kg each of Se and Zn and group 4 received 2.25 mg.Kg each of Se and Zn only. The duration of treatment was 56 days following which the animals were sacrificed by the 57 th day and testes fixed in Bouin’s fluid. Result: Pb induced toxicity could be apoptotic involving ROS activation of NO-dependent apoptotic pathway or necrotic involving a wide range damage by ROS induced lipid peroxidation. Selenium and zinc treatment ameliorated the damage induced by lead toxicity in the germinal epithelium. Conclusion: ALPis involved in intrinsic regulation of DNA cleavage in apoptosis by functioning similar to endonucleases and also regulates membrane transport in perioxidated biomembranes. PLAPexpression is minimal as tumorgenesis was not recorded, although Pb treatment showed signs of epithelium of endothelial cancer signalling, which was ameliorated by Se+Zn treatment

    Molecular Characterization of Alkaline Phosphatase and PLAP in the Germinal Epithelium of Pb and Se+Zn Treated Adult Sprague Dawley Rats

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    Aim: The role of alkaline phosphatase in cell metabolism and regulation is essential and cuts across cell proliferation, division, cell death, membrane transport and DNA cleavage. This study addresses the role and importance of alkaline phosphates (ALP) and Placenta Alkaline phosphatase (PLAP) in the cells of germinal epithelium of male Rat testes following induced lead (Pb) toxicity and rejuvenation by Selenium (Se) and Zinc (Zn) treatment. Method: Adult Sprague-Dawley Rats (males) were divided into 4 groups of 15 animals each and were treated as thus; Group 1: Normal saline and serves as the control, Group 2: 100 mg/Kg BW of Pb only, Group 3: 100 mg/Kg BW of Pb and 2.25 mg/Kg each of Se and Zn and group 4 received 2.25 mg.Kg each of Se and Zn only. The duration of treatment was 56 days following which the animals were sacrificed by the 57 th day and testes fixed in Bouin’s fluid. Result : Pb induced toxicity could be apoptotic involving ROS activation of NO-dependent apoptotic pathway or necrotic involving a wide range damage by ROS induced lipid peroxidation. Selenium and zinc treatment ameliorated the damage induced by lead toxicity in the germinal epithelium. Conclusion : ALP is involved in intrinsic regulation of DNA cleavage in apoptosis by functioning similar to endonucleases and also regulates membrane transport in perioxidated biomembranes. PLAP expression is minimal as tumorgenesis was not recorded, although Pb treatment showed signs of epithelium of endothelial cancer signalling, which was ameliorated by Se+Zn treatmen

    The contribution of diet and genotype to iron status in women:a classical twin study

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    This is the first published report examining the combined effect of diet and genotype on body iron content using a classical twin study design. The aim of this study was to determine the relative contribution of genetic and environmental factors in determining iron status. The population was comprised of 200 BMI- and age-matched pairs of MZ and DZ healthy twins, characterised for habitual diet and 15 iron-related candidate genetic markers. Variance components analysis demonstrated that the heritability of serum ferritin (SF) and soluble transferrin receptor was 44% and 54% respectively. Measured single nucleotide polymorphisms explained 5% and selected dietary factors 6% of the variance in iron status; there was a negative association between calcium intake and body iron (p = 0.02) and SF (p = 0.04)

    Rab3D is critical for secretory granule maturation in PC12 cells.

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    Neuropeptide- and hormone-containing secretory granules (SGs) are synthesized at the trans-Golgi network (TGN) as immature secretory granules (ISGs) and complete their maturation in the F-actin-rich cell cortex. This maturation process is characterized by acidification-dependent processing of cargo proteins, condensation of the SG matrix and removal of membrane and proteins not destined to mature secretory granules (MSGs). Here we addressed a potential role of Rab3 isoforms in these maturation steps by expressing their nucleotide-binding deficient mutants in PC12 cells. Our data show that the presence of Rab3D(N135I) decreases the restriction of maturing SGs to the F-actin-rich cell cortex, blocks the removal of the endoprotease furin from SGs and impedes the processing of the luminal SG protein secretogranin II. This strongly suggests that Rab3D is implicated in the subcellular localization and maturation of ISGs

    Evidence for solar cycles in a late Holocene speleothem record from Dongge Cave, China

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    The association between solar activity and Asian monsoon (AM) remains unclear. Here we evaluate the possible connection between them based on a precisely-dated, high-resolution speleothem oxygen isotope record from Dongge Cave, southwest China during the past 4.2 thousand years (ka). Without being adjusted chronologically to the solar signal, our record shows a distinct peak-to-peak correlation with cosmogenic nuclide 14C, total solar irradiance (TSI) and sunspot number (SN) at multi-decadal to centennial timescales. Further cross-wavelet analyses between our calcite δ18O and atmospheric 14C show statistically strong coherence at three typical periodicities of ~80, 200 and 340 years, suggesting important roles of solar activities in modulating AM changes at those timescales. Our result has further indicated a better correlation between our calcite δ18O record and atmospheric 14C than between our record and TSI. This better correlation may imply that the Sun–monsoon connection is dominated most likely by cosmic rays and oceanic circulation (both associated to atmospheric 14C), instead of the direct solar heating (TSI)

    A distal region of the human TGM1 promoter is required for expression in transgenic mice and cultured keratinocytes

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    BACKGROUND: TGM1(transglutaminase 1) is an enzyme that crosslinks the cornified envelope of mature keratinocytes. Appropriate expression of the TGM1 gene is crucial for proper keratinocyte function as inactivating mutations lead to the debilitating skin disease, lamellar ichthyosis. TGM1 is also expressed in squamous metaplasia, a consequence in some epithelia of vitamin A deficiency or toxic insult that can lead to neoplasia. An understanding of the regulation of this gene in normal and abnormal differentiation states may contribute to better disease diagnosis and treatment. METHODS: In vivo requirements for expression of the TGM1 gene were studied by fusing various lengths of promoter DNA to a reporter and injecting the DNA into mouse embryos to generate transgenic animals. Expression of the reporter was ascertained by Western blotting and immunohistochemistry. Further delineation of a transcriptionally important distal region was determined by transfections of progressively shortened or mutated promoter DNA into cultured keratinocytes. RESULTS: In vivo analysis of a reporter transgene driven by the TGM1 promoter revealed that 1.6 kilobases, but not 1.1 kilobases, of DNA was sufficient to confer tissue-specific and cell layer-specific expression. This same region was responsible for reporter expression in tissues undergoing squamous metaplasia as a response to vitamin A deprivation. Mutation of a distal promoter AP1 site or proximal promoter CRE site, both identified as important transcriptional elements in transfection assays, did not prevent appropriate expression. Further searching for transcriptional elements using electrophoretic mobility shift (EMSA) and transfection assays in cultured keratinocytes identified two Sp1 elements in a transcriptionally active region between -1.6 and -1.4 kilobases. While mutation of either Sp1 site or the AP1 site singly had only a small effect, mutation of all three sites eliminated nearly all the transcriptional activity. CONCLUSIONS: A distal region of the TGM1 gene promoter, containing AP1 and Sp1 binding sites, is evolutionarily conserved and responsible for high level expression in transgenic mice and in transfected keratinocyte cultures

    Mechanism and timing of Mcm2–7 ring closure during DNA replication origin licensing

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    The opening and closing of two ring-shaped Mcm2-7 DNA helicases is necessary to license eukaryotic origins of replication, although the mechanisms controlling these events are unclear. The origin-recognition complex (ORC), Cdc6 and Cdt1 facilitate this process by establishing a topological link between each Mcm2-7 hexamer and origin DNA. Using colocalization single-molecule spectroscopy and single-molecule Förster resonance energy transfer (FRET), we monitored ring opening and closing of Saccharomyces cerevisiae Mcm2-7 during origin licensing. The two Mcm2-7 rings were open during initial DNA association and closed sequentially, concomitant with the release of their associated Cdt1. We observed that ATP hydrolysis by Mcm2-7 was coupled to ring closure and Cdt1 release, and failure to load the first Mcm2-7 prevented recruitment of the second Mcm2-7. Our findings identify key mechanisms controlling the Mcm2-7 DNA-entry gate during origin licensing, and reveal that the two Mcm2-7 complexes are loaded via a coordinated series of events with implications for bidirectional replication initiation and quality control.National Institutes of Health (U.S.) (Grant R01 GM52339)National Institutes of Health (U.S.) (Pre-Doctoral Training Grant GM007287)National Cancer Institute (U.S.) (Koch Institute Support Grant P30-CA14051
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