1,851 research outputs found

    Government and private sector joint venturing in natural resource development: The Queensland plantation forestry joint venture scheme

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    This paper examines the role of joint ventures between government and resource owners to develop natural resources, with particular reference for forestry plantations. Findings of a survey of landholders participating or expressing interest in the Queensland Plantation Joint Venture Scheme are presented. Joint venture arrangements are found to overcome investment constraints, particularly with respect to capital, technical knowledge and resource security. Complementarities between resource supplies of joint venture partners lead to increased output relative to wholly owned investments. Participants expressed a high degree of satisfaction with this program, although making some suggestions for changes in arrangements. Plantation joint ventures can contribute towards timber self-sufficiency and to ecologically sustainable land-use. Opportunities exist for joint ventures between government and private firms with respect to other natural-resource-based enterprises where market failure is apparent

    Identification and analysis of cassava genotype TME3 bacteria artificial chromosome libraries for characterization of the cassava mosaic disease

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    Cassava is an economically important crop in sub-Saharan Africa; however, its yield potential is constrained by cassava mosaic disease (CMD) infection. Classical genetics and biotechnology are being harnessed to overcome the disease and secure yields for farmers. The CMD2 resistance locus flanked by three simple sequence repeats (SSR) markers and one sequence characterized amplified region (SCAR) marker were mapped in West African genotypes and shown to impart qualitative resistant to all species of CMGs. However, gene(s) associated with the CMD2 locus and their mode of actions remains unknown. In an effort to discover gene(s) located in CMD2 locus region, TME3 BAC collections were screened for the presence of CMD2 flanking markers. CMD susceptible and resistant cassava genotypes were found to contain 100% of the markers flanking CMD2 locus. SNPs and nucleotide deletions were identified within the marker sequences but there was no evidence of trait and marker association. All the SSR markers flanking CMD2, and the more recently characterized CMD3 loci were to be located on chromosome 12. Through BAC pools library hybridization with marker probes, 130 BACs were identified, but only 23 BACs contained at least CMD2 specific two markers. Whole BAC sequencing identified five clones that mapped to the marker regions. BAC29 assembled into a 100 kb contig and encoded tandem repeats of three full length R genes (3.5 kb) and two partial repeats. These R genes were conserved and highly expressed in CMD susceptible and CMD resistant cassava genotypes. Promoter sequences derived from R genes showed similar transient expression of GUS as 35S promoter. On cassava genome V6.1 BAC29 sequences were mapped to chromosome 16, eliminating their potential role in CMD resistant.Keywords: Bacteria artificial chromosome, CMD2, cassava, cassava mosaic diseas

    Ablation of smooth muscle myosin heavy chain SM2 increases smooth muscle contractility and results in postnatal death in mice

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    The smooth muscle myosin heavy chains (SMHC) are motor proteins powering smooth muscle contraction. Alternate splicing of SHMC gene at the C-terminus produces SM1, and SM2 myosin isoforms; SM2 (200 kDa) contains a unique 9-amino-acid sequence at the carboxyl terminus, whereas SM1 (204 kDa) has a 43 amino acid non-helical tail region. To date the functional difference between C-terminal isoforms has not been established; therefore, we used an exon-specific gene targeting strategy and generated a mouse model specifically deficient in SM2. Deletion of exon-41 of the SMHC gene resulted in a complete loss of SM2 in homozygous (_SM2^-/-^_) mice, accompanied by a concomitant down-regulation of SM1 in bladders. While heterozygous (_SM2^+/-^_) mice appeared normal and fertile, _SM2^-/-^_ mice died within 30 days after birth. The peri-mortal _SM2^-/-^_ mice showed reduced body weight, distention of the bladder and alimentary tract, and end-stage hydronephrosis. Interestingly, strips from _SM2^-/-^_ bladders showed increased contraction to K^+^ depolarization or M3 receptor activation. These results suggest that SM2 myosin has a distinct functional role in smooth muscle, and the deficiency of SM2 increases smooth muscle contractility, and causes dysfunctions of smooth muscle organs, including the bladder that leads to the end-stage hydronephrosis and postnatal death

    Evaluation of resistance reaction of maize germplasm to common foliar diseases in Kenya

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    Use of resistance varieties is the most practical method of managing crop diseases. There is a great variation in terms of resistance reaction to diseases among the various maize germplasm and with the liberization of seed market, the sector has witnessed proliferation of massive introduction of new varieties whose reaction to diseases cannot be ascertained. This study was conducted to evaluate the reaction of maize varieties to northern leaf blight (NLB), common maize rust, gray leaf spot (GLS) and maize streak disease (MSD). The experiment was conducted at Kabete Field Station, University of Nairobi for two seasons namely short rains and long rains. The germplasm was bought from the commercial seed stockists and the landraces obtained from KARI Katumani and from farmers. The diseases were assessed by monitoring and scoring for disease incidence and severity. The appropriate scoring keys were used for determination of disease severity. All the varieties showed symptoms of the four diseases in both seasons but the intensity of the diseases differed significantly among the different varieties. Disease incidence was highest for common rust with a mean of 14.29% for the variety DH04, while disease incidence was highest (19.21%) for northern leaf blight in season two for Kinyanya which is a landrace. Gray leaf spot and the common smuts had the lowest mean incidence ranging from 0 to 0.25% for common smut and 0 to 2.6% for gray leaf spot. Season two had comparatively higher disease incidence means compared to season one. Meteorological data showed that season two had more rains and this explains the reasons behind this. Though all the varieties screened were found to be affected by the diseases to various levels, the varieties displayed significant differences in the disease incidence and severity. This shows that use of resistance varieties should be considered in the management of maize diseases. Focus should also be on pyramiding genes for resistance in the breeding programmes to develop varieties with multiple resistance to different diseases. Key words: Disease incidence and severity, disease score, symptoms, varietie

    Assessment of urinary deoxynivalenol biomarkers in UK children and adolescents

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    © 2018 by the authors. Licensee MDPI, Basel, Switzerland. Deoxynivalenol (DON), the mycotoxin produced mainly by Fusarium graminearum and found in contaminated cereal-based foodstuff, has been consistently detected in body fluids in adults. Available data in children and adolescents are scarce. This study assessed urinary DON concentrations in children aged 3–9 years (n = 40) and adolescents aged 10–17 years (n = 39) in the UK. Morning urine samples were collected over two consecutive days and analysed for free DON (un-metabolised form), DON-glucuronides (DON-GlcA), deepoxy deoxynivalenol (DOM-1), and total DON (sum of free DON, DON-GlcA, and DOM-1). Total DON was detected in the urine of > 95% of children and adolescents on both days. Mean total DON concentrations (ng/mg creatinine) were 41.6 and 21.0 for children and adolescents, respectively. The greatest total DON levels were obtained in female children on both days (214 and 219 ng/mg creatinine on days 1 and 2, respectively). Free DON and DON-GlcA were detected in most urine specimens, whereas DOM-1 was not present in any sample. Estimation of dietary DON exposure suggested that 33–63% of children and 5–46% of adolescents exceeded current guidance regarding the maximum provisional tolerable daily intake (PMTDI) for DON. Although moderate mean urinary DON concentrations were shown, the high detection frequency of urinary DON, the maximum biomarker concentrations, and estimated dietary DON exposure are concerning

    Thermoreversible gelation in poly(ethylene oxide)/carbon black hybrid melts

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    The study focuses on the structure and viscoelasticity of poly(ethylene oxide)/carbon black fluids. The hybrids when subjected to extreme thermal annealing (at temperatures far above the melting point of the matrix) exhibit a 3-4 orders of magnitude increase in viscosity. Surprisingly, the effect is reversible and the viscosity reverts back to its initial value upon subsequent cooling. This rather unique sol-gel transition in terms of strength, steepness and thermal reversibility points to major structural rearrangements via extensive particle clustering, in agreement with microscopy observations. In related systems it was found that when matrix-particle electrostatic interactions are present the gelation is essentially diminished

    STAT3 can serve as a hit in the process of malignant transformation of primary cells

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    The transcription factor signal transducer and activator of transcription 3 (STAT3) acts downstream of many pro-oncogenic signals, including cytokines, growth factors and oncogenes, and is accordingly constitutively active in a wide variety of tumors that often become addicted to it. Moreover, STAT3 is a key player in mediating inflammation-driven tumorigenesis, where its aberrant continuous activation is typically triggered by local or systemic production of the pro-inflammatory cytokine IL-6. We recently showed that mouse embryonic fibroblasts (MEFs) derived from STAT3C k/in mice, which express physiological levels of the constitutively active mutant STAT3C, display features of transformed cells such as increased proliferation, resistance to apoptosis and senescence, and aerobic glycolysis. Here, we show that pre-existing constitutively active STAT3 is sufficient to prime primary MEFs for malignant transformation upon spontaneous immortalization. Transformation is strictly STAT3-dependent and correlates with high resistance to apoptosis and enhanced expression of anti-apoptotic/pro-survival genes. Additionally, hypoxia inducible factor (HIF)-1α level is elevated by twofold and contributes to STAT3 oncogenic activity by supporting high rates of aerobic glycolysis. Thus, constitutively active STAT3, an accepted essential factor for tumor growth/progression, can also act as a first hit in multistep carcinogenesis; this ability to predispose cells to malignant transformation may be particularly relevant in the pro-oncogenic niche represented by chronically inflamed tissues
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