600 research outputs found
Alternative business models for forest - dependent communities in Africa: A pragmatic consideration of small - scale enterprises and a path forward
The dominant mode of business practice in the African forest
sector β especially in the high forest cover regions β comes in
the form of concessionaires operating on publicly held lands. Increasingly, however, the concession - based model is being
challenged. Is it socially and environmentally sustainable? Does
it lead to positive socio - economic outcomes for forest dependent communities? While this paper does not attempt to answer these questions head - on, it does put forward four alternative business models that could serve to reduce poverty and improve social conditions among rural forest - dwelling Africans:
1) small and medium - sized enterprises; 2) community forest
enterprises; 3) business associations; and 4) alliances with
concessionaires.
Definitions of the four business models are provided, and some key considerations for each are discussed. The paper concludes by providing recommendations for civil society, governments, economic actors, communities, and other stakeholders interested in catalyzing and creating an enabling environment for these sorts of business alternatives to succeed in the forested regions of Africa. Namely, there is a need to
collect and disseminate quantitative data on the socio - economic contributions that small - scale enterprises can make, devise appropriate interventions that take into account the highly variable socio - political landscapes of Africa, and develop business plans grounded in solid, marketable value propositions
Inherent Plasticity of Brown Adipogenesis in White Fat of Mice Allows for Recovery from Effects of Post-Natal Malnutrition
Interscapular brown adipose tissue (iBAT) is formed during fetal development and stable for the life span of the mouse. In addition, brown adipocytes also appear in white fat depots (wBAT) between 10 and 21 days of age in mice maintained at a room temperature of 23Β°C. However, this expression is transient. By 60 days of age the brown adipocytes have disappeared, but they can re-emerge if the adult mouse is exposed to the cold (5Β°C) or treated with Ξ²3-adrenergic agonists. Since the number of brown adipocytes that can be induced in white fat influences the capacity of the mouse to resist the obese state, we determined the effects of the nutritional conditions on post-natal development (birth to 21 days) of wBAT and its long-term effects on diet-induced obesity (DIO). Under-nutrition caused essentially complete suppression of wBAT in inguinal fat at 21 days of age, as indicated by expression of Ucp1 and genes of mitochondrial structure and function based upon microarray and qRT-PCR analysis, whereas over-nutrition had no discernible effects on wBAT induction. Surprisingly, the suppression of wBAT at 21 days of age did not affect DIO in adult mice maintained at 23Β°C, nor did it affect the reduction in obesity or cold tolerance when DIO mice were exposed to the cold at 5Β°C for one week. Gene expression analysis indicated that mice raised under conditions that suppressed wBAT at 21 days of age were able to normally induce wBAT as adults. Therefore, neither severe hypoleptinemia nor hypoinsulinemia during suckling permanently impaired brown adipogenesis in white fat. In addition, energy balance studies of DIO mice exposed to cold indicates that mice with reduced adipose stores preferentially increased food intake, whereas those with larger adipose tissue depots preferred to utilize energy from their adipose stores
A 13 base pair deletion in exon 1 of HPRT Illinois forms a functional GUG initiation codon
More than 50 mutations in the human hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus have been described, yet only 2 alter the AUG initiation codon. One, variant HPRT 1151 , results in Lesch-Nyhan syndrome (LNS), and the other, HPRT Illinois , results in partial HPRT deficiency. Although previously undetectable, we used a sensitive gel assay to demonstrate that HPRT Illinois is not only active, but has a native Mr indistinguishable from normal. Confirmatory evidence of activity and native Mr is demonstrated following transfection of HPRT cells with expression plasmids containing cDNA sequences representing HPRT Illinois . These data provide support for the hypothesis that patient RT, or variant HPRT Illinois , is spared manifestations of the LNS as a result of translation at the newly formed GUG initiation codon.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47636/1/439_2004_Article_BF00212027.pd
Why Does the Giant Panda Eat Bamboo? A Comparative Analysis of Appetite-Reward-Related Genes among Mammals
Background: The giant panda has an interesting bamboo diet unlike the other species in the order of Carnivora. The umami taste receptor gene T1R1 has been identified as a pseudogene during its genome sequencing project and confirmed using a different giant panda sample. The estimated mutation time for this gene is about 4.2 Myr. Such mutation coincided with the giant pandaβs dietary change and also reinforced its herbivorous life style. However, as this gene is preserved in herbivores such as cow and horse, we need to look for other reasons behind the giant pandaβs diet switch. Methodology/Principal Findings: Since taste is part of the reward properties of food related to its energy and nutrition contents, we did a systematic analysis on those genes involved in the appetite-reward system for the giant panda. We extracted the giant panda sequence information for those genes and compared with the human sequence first and then with seven other species including chimpanzee, mouse, rat, dog, cat, horse, and cow. Orthologs in panda were further analyzed based on the coding region, Kozak consensus sequence, and potential microRNA binding of those genes. Conclusions/Significance: Our results revealed an interesting dopamine metabolic involvement in the pandaβs food choice
Blockade of TRPM7 Channel Activity and Cell Death by Inhibitors of 5-Lipoxygenase
TRPM7 is a ubiquitous divalent-selective ion channel with its own kinase domain. Recent studies have shown that suppression of TRPM7 protein expression by RNA interference increases resistance to ischemia-induced neuronal cell death in vivo and in vitro, making the channel a potentially attractive pharmacological target for molecular intervention. Here, we report the identification of the 5-lipoxygenase inhibitors, NDGA, AA861, and MK886, as potent blockers of the TRPM7 channel. Using a cell-based assay, application of these compounds prevented cell rounding caused by overexpression of TRPM7 in HEK-293 cells, whereas inhibitors of 12-lipoxygenase and 15-lipoxygenase did not prevent the change in cell morphology. Application of the 5-lipoxygenase inhibitors blocked heterologously expressed TRPM7 whole-cell currents without affecting the protein's expression level or its cell surface concentration. All three inhibitors were also effective in blocking the native TRPM7 current in HEK-293 cells. However, two other 5-lipoxygenase specific inhibitors, 5,6-dehydro-arachidonic acid and zileuton, were ineffective in suppressing TRPM7 channel activity. Targeted knockdown of 5-lipoxygenase did not reduce TRPM7 whole-cell currents. In addition, application of 5-hydroperoxyeicosatetraenoic acid (5-HPETE), the product of 5-lipoxygenase, or 5-HPETE's downstream metabolites, leukotriene B4 and leukotriene D4, did not stimulate TRPM7 channel activity. These data suggested that NDGA, AA861, and MK886 reduced the TRPM7 channel activity independent of their effect on 5-lipoxygenase activity. Application of AA861 and NDGA reduced cell death for cells overexpressing TRPM7 cultured in low extracellular divalent cations. Moreover, treatment of HEK-293 cells with AA861 increased cell resistance to apoptotic stimuli to a level similar to that obtained for cells in which TRPM7 was knocked down by RNA interference. In conclusion, NDGA, AA861, and MK886 are potent blockers of the TRPM7 channel capable of attenuating TRPM7's function during cell stress, making them effective tools for the biophysical characterization and suppression of TRPM7 channel conductance in vivo
Two Genetic Determinants Acquired Late in Mus Evolution Regulate the Inclusion of Exon 5, which Alters Mouse APOBEC3 Translation Efficiency
Mouse apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like editing complex 3 (mA3), an intracellular antiviral factor, has 2 allelic variations that are linked with different susceptibilities to beta- and gammaretrovirus infections among various mouse strains. In virus-resistant C57BL/6 (B6) mice, mA3 transcripts are more abundant than those in susceptible BALB/c mice both in the spleen and bone marrow. These strains of mice also express mA3 transcripts with different splicing patterns: B6 mice preferentially express exon 5-deficient (Ξ5) mA3 mRNA, while BALB/c mice produce exon 5-containing full-length mA3 mRNA as the major transcript. Although the protein product of the Ξ5 mRNA exerts stronger antiretroviral activities than the full-length protein, how exon 5 affects mA3 antiviral activity, as well as the genetic mechanisms regulating exon 5 inclusion into the mA3 transcripts, remains largely uncharacterized. Here we show that mA3 exon 5 is indeed a functional element that influences protein synthesis at a post-transcriptional level. We further employed in vitro splicing assays using genomic DNA clones to identify two critical polymorphisms affecting the inclusion of exon 5 into mA3 transcripts: the number of TCCT repeats upstream of exon 5 and the single nucleotide polymorphism within exon 5 located 12 bases upstream of the exon 5/intron 5 boundary. Distribution of the above polymorphisms among different Mus species indicates that the inclusion of exon 5 into mA3 mRNA is a relatively recent event in the evolution of mice. The widespread geographic distribution of this exon 5-including genetic variant suggests that in some Mus populations the cost of maintaining an effective but mutagenic enzyme may outweigh its antiviral function
Localization of Human RNase Z Isoforms: Dual Nuclear/Mitochondrial Targeting of the ELAC2 Gene Product by Alternative Translation Initiation
RNase Z is an endonuclease responsible for the removal of 3β² extensions from tRNA precursors, an essential step in tRNA biogenesis. Human cells contain a long form (RNase ZL) encoded by ELAC2, and a short form (RNase ZS; ELAC1). We studied their subcellular localization by expression of proteins fused to green fluorescent protein. RNase ZS was found in the cytosol, whereas RNase ZL localized to the nucleus and mitochondria. We show that alternative translation initiation is responsible for the dual targeting of RNase ZL. Due to the unfavorable context of the first AUG of ELAC2, translation apparently also starts from the second AUG, whereby the mitochondrial targeting sequence is lost and the protein is instead routed to the nucleus. Our data suggest that RNase ZL is the enzyme involved in both, nuclear and mitochondrial tRNA 3β² end maturation
Immunogenic Comparison of Chimeric Adenovirus 5/35 Vector Carrying Optimized Human Immunodeficiency Virus Clade C Genes and Various Promoters
Adenovirus vector-based vaccine is a promising approach to protect HIV infection. However, a recent phase IIb clinical trial using the vector did not show its protective efficacy against HIV infection. To improve the vaccine, we explored the transgene protein expression and its immunogenicity using optimized codon usage, promoters and adaptors. We compared protein expression and immunogenicity of adenovirus vector vaccines carrying native or codon usage-optimized HIV-1 clade C gag and env genes expression cassettes driven by different promoters (CMV, CMVi, and CA promoters) and adapters (IRES and F2A). The adenovirus vector vaccine containing optimized gag gene produced higher Gag protein expression and induced higher immune responses than the vector containing native gag gene in mice. Furthermore, CA promoter generated higher transgene expression and elicited higher immune responses than other two popularly used promoters (CMV and CMVi). The second gene expression using F2A adaptor resulted in higher protein expression and immunity than that of using IRES and direct fusion protein. Taken together, the adenovirus vector containing the expression cassette with CA promoter, optimized HIV-1 clade C gene and an F2A adaptor produced the best protein expression and elicited the highest transgene-specific immune responses. This finding would be promising for vaccine design and gene therapy
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