11,570 research outputs found

    Homeoprotein Hbx4 represses adhesion molecule governing cytokinesis and development

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    Homeobox genes encode proteins with a highly conserved DNA-binding motif and provoke morphological diversification of body segments by differentially controlling the expression of downstream targets. Here, we have identified _hbx4_, one of many homeobox genes in _Dictyostelium discoideum_ and investigated its role during growth and development. In suspension, Hbx4-overexpressing cells, Hbx4^OE^, showed defects in cytokinesis and growth rate. During development, Hbx4^OE^ and _hbx4_-disrupting cells, _hbx4¯_ made differences in shape of mound and slug, cell-type proportioning from wild type KAx3 cells. These phenotypes were similar to those of mutant defective in _cadA_ encoding Ca^2+^-dependent cell adhesion molecule so that we investigated the relationship between _hbx4_ and _cadA_. Overexpression of Hbx4 inhibited the expression of _cadA_ and cAMP also failed to stimulate _cadA_ in Hbx4^OE^. Furthermore, gel mobility shift assay showed the promoter of _cadA_ contained Hbx4-binding site, indicating Hbx4 negatively regulates the expression of _cadA_. Proteome analysis revealed that overexpression of Hbx4 repressed the _rdiA_ and _abpB_ encoding rho guanine nucleotide dissociation inhibitor1, RhoGDI1 and actin bundling protein 34, ABP34, respectively. And the overexpression of _cadA_ in Hbx4^OE^ cells rescued the defects and increased mRNA level of _rdiA_, _abpB_ and one of Rho GTPase, _rac1b_. These results suggested that Hbx4 can modulate cytokinesis, cell sorting and cell-type proportioning by repressing _cadA_ that regulates GTPase-dependent signaling pathway

    Evaluation of four apicultural products for hive colonization by honey bees (Apis mellifera adansonii) (Hymenoptera: apidae) and pre-colonization pests

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    Four apicultural products (honey, bee wax, slum gum and propolis) were evaluated for their potentials to attract the African honey bee (Apis mellifera adansonii) colony into artificial hives and their effect on infestation by apicultural insect pests. Ten grammes each of propolis, bee wax and slum gum and 10 ml of honey were applied at the flight entrance, walls of the hives and on the top bars. Data were collected on type and number of pre-colonization pests, hive colonization, colony weight gain, weight of matured harvested combs and weight of extracted honey from the harvested combs. Statistical analysis of the data was carried out using analysis of variance and means were separated with Tukeys’ HSD at 5% level of probability. Slum gum-baited hives were the first to be colonized (10 days post hive installation) (DPI), followed by bee wax (26.5 DPI). Bee wax however had the highest percentage hive colonization (66.67%) which was not significantly (P>0.05) different from 33.33% observed in other apicultural products. Weight gain on weekly basis did not follow a regular pattern for 2-10 weeks after colonization (WAC); but at 12-16 WAC, hives baited with bee wax had the highest weekly weight gain. In terms of total harvest, the performance of the different baiting materials was as follows: slum gum > bee wax > honey > propolis. However, percentage honey yield was highest in hives baited with bee wax and lowest in propolis-baited hives. The two pests encountered at the pre-colonization stage were waiver ant (Oecophylla longinuda) and sugar ant (Camponotus consobrinus). O. longinuda was significantly (P<0.05) highest (17.33) in honey baited hives than any other baiting material at 2 DPI. Slum gum and honey attracted more sugar ants at 2-4 DPI than bee wax. At 3 DPI, O. longinuda was significantly (P<0.05) higher in slum gum than bee wax; but the later performed better with significantly lower level of pre-colonization pest infestation.Keywords: pest, wax, honey, propolis, slum-gu

    Variations in the Fibre Length of Rubber Wood (Hevea Brasiliensis (Kunth) Muel Arg) Grown in South Eastern Nigeria

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    Variations in the fibre length of rubber wood were investigated to determine suitability of the wood fibres for some industrial utilization. The fibre lengths were sampled according to main effects such as plantations effects, bud classes effects, trees effects, discs effects, cardinal directions effects and ring-blocks (radii) effects to determine variations in composition, based on the fixed effects model of a nested design. Macerated wood samples obtained at parallel positions to the grain were magnified on a visopan microscope and investigated in order of the sampled main effects. The plantations and bud classes effects were not significant (p>0.05), while the trees effects was highly significant (p<0.01). The effects of disc (position along the bole) and ring blocks (radii) were not significant (p> 0.05) on the fibre length composition. The cardinal directions effects was highly significant (p<0.01). The effects of factor interactions on fibre lengths were also investigated but not of practical importance. The mean fibre length value of sample trees was 1.59mm making it suitable for pulp and paper production

    A partial skeleton of an enantiornithine bird from the early Cretaceous of northwestern China

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    Although recent discoveries from Lower Cretaceous sediments in northeastern China have greatly improved our understanding of the initial stages of avian diversification in eastern Asia, the early evolution of Aves elsewhere on the continent remains poorly understood. In 2004, a collaborative field effort directed by personnel from the Chinese Academy of Geological Sciences and Carnegie Museum of Natural History recovered multiple partial to nearly complete avian skeletons from outcrops of the Lower Cretaceous Xiagou Formation exposed in the Changma Basin of northwestern Gansu Province, China. Here we describe a thrush-sized partial skeleton comprised of a fragmentary pelvic girdle and largely complete hind limbs. A phylogenetic analysis of 20 avian ingroup taxa and 169 anatomical characters places the specimen in Enantiomithes, and within that clade, in Enenantiomithes. When coupled with additional recent discoveries from the Changma Basin, the new skeleton improves our understanding of early avian evolution and diversification in central Asia

    Observations on in vitro behaviour of the zygotic axes of fluted pumpkin

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    Fluted pumpkin, Telfairia occidentalis Hook. f., is an important leaf and seed vegetable and a local medicinal plant across West Africa. Many biological constraints have become potent threats to the existence of the plant necessitating an urgent need to collect and conserve the existing narrow genetic diversity. However, conservation by seed storage is impossible because the seed is recalcitrant, that is desiccation- and chilling-sensitive. Micropropagation is the only immediate alternative option for the conservation of fluted pumpkin germplasm. In order to facilitate this, the behaviour of excised embryonic axes and shoot tips of fluted pumpkin under in vitro conditions were investigated. Systemic infection of seeds from field led to frequent and high microbial contamination in culture. There was interaction between the type of microbial contamination and the storage environment of seeds prior to excision of the axes. Axes greened under low light intensity and root growth was dependent on the orientation of the axes. In general, zygotic axes of the plant are easy to grow in vitro under a range of nutrient media and culture condition

    Mixed chemical-induced oxidative stress in occupational exposure in Nigerians

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    Exposure to single chemicals and associated disorders in occupational environments has received significant attention. Understanding these events holds great promise for risk identification, assessmentand chemical induced disease prevention. Fifty (50) fasting male workers, age range 18-50 years exposed to chemical mixtures in a works department, mean duration 17.7±10.1 years and 30 controlsmatched for age, diet, sex and other demographic characteristics except exposure to chemicals were selected. Body mass index (BMI), antioxidant status and other biochemical indices including plasmaproteins (total protein) and subsets, albumin and total globulins were determined in plasma. The BMI was similar between chemical workers (exposed) and controls (p>0.05). Uric acid level was significantlyhigher in the exposed than in the controls (

    Coccolithoviruses: A review of cross‐kingdom genomic thievery and metabolic thuggery

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    This is the final version. Available on open access from MDPI via the DOI in this recordCoccolithoviruses (Phycodnaviridae) infect and lyse the most ubiquitous and successful coccolithophorid in modern oceans, Emiliania huxleyi. So far, the genomes of 13 of these giant lytic viruses (i.e., Emiliania huxleyi viruses—EhVs) have been sequenced, assembled, and annotated. Here, we performed an in‐depth comparison of their genomes to try and contextualize the ecological and evolutionary traits of these viruses. The genomes of these EhVs have from 444 to 548 coding sequences (CDSs). Presence/absence analysis of CDSs identified putative genes with particular ecological significance, namely sialidase, phosphate permease, and sphingolipid biosynthesis. The viruses clustered into distinct clades, based on their DNA polymerase gene as well as full genome comparisons. We discuss the use of such clustering and suggest that a gene‐by‐gene investigation approach may be more useful when the goal is to reveal differences related to functionally important genes. A multi domain “Best BLAST hit” analysis revealed that 84% of the EhV genes have closer similarities to the domain Eukarya. However, 16% of the EhV CDSs were very similar to bacterial genes, contributing to the idea that a significant portion of the gene flow in the planktonic world inter‐crosses the domains of life.This work was funded by the NERC Oceans 2025 program, Plymouth Marine Laboratory’s Research Program, and a NERC PhD grant awarded to J.I.N. supervised by M.J.A. and S.A.K. at Plymouth Marine Laboratory

    Chloroxine overrides DNA damage tolerance to restore platinum sensitivity in high-grade serous ovarian cancer

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    High-grade serous cancer (HGSC) accounts for ~67% of all ovarian cancer deaths. Although initially sensitive to platinum chemotherapy, resistance is inevitable and there is an unmet clinical need for novel therapies that can circumvent this event. We performed a drug screen with 1177 FDA-approved drugs and identified the hydroxyquinoline drug, chloroxine. In extensive validation experiments, chloroxine restored sensitivity to both cisplatin and carboplatin, demonstrating broad synergy in our range of experimental models of platinum-resistant HGSC. Synergy was independent of chloroxine’s predicted ionophore activity and did not relate to platinum uptake as measured by atomic absorption spectroscopy. Further mechanistic investigation revealed that chloroxine overrides DNA damage tolerance in platinum-resistant HGSC. Co-treatment with carboplatin and chloroxine (but not either drug alone) caused an increase in γH2AX expression, followed by a reduction in platinum-induced RAD51 foci. Moreover, this unrepaired DNA damage was associated with p53 stabilisation, cell cycle re-entry and triggering of caspase 3/7- mediated cell death. Finally, in our platinum-resistant, intraperitoneal in vivo model, treatment with carboplatin alone resulted in a transient tumour response followed by tumour regrowth. In contrast, treatment with chloroxine and carboplatin combined, was able to maintain tumour volume at baseline for over 4 months. In conclusion, our novel results show that chloroxine facilitates platinum-induced DNA damage to restore platinum sensitivity in HGSC. Since chloroxine is already licensed, this exciting combination therapy could now be rapidly translated for patient benefit

    First detection of small hive beetle Aethina tumida Murray (Coleoptera: Nitidulidae) infesting eastern honeybee, Apis cerana Fabricius (Hymenoptera: Apidae), in China

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    We report the infestation of small hive beetle, Aethina tumida, in a honeybee, Apis cerana, in South China. This is the first record for domestic Chinese honey bee infested with small hive beetle
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