Protein composition of the chromosomal scaffold and interphase nuclear matrix

Residual protein structures were prepared from isolated chromosomes and interphase nuclei of in vitro cultured bovine liver cells and the protein compositions were analysed. Chromosomes with minimal cytoplasmic contamination were obtained by a simple procedure using a pH 8 isolation medium containing Triton X-100 and polyamines, and residual protein-DNA complexes were prepared by extraction with 2 M NaCl. Residual protein structures were also obtained by digesting isolated chromosomes with staphylococcal nuclease. Protein compositions of both structures as obtained by SDS-polyacrylamide gel electrophoresis were essentially the same. Residual protein structures were prepared from isolated nuclei by the same procedures. The major nuclear matrix proteins, i.e., the lamins A, B, and C, were not found in the chromosomes and chromosome scaffolds. On the other hand, the residual chromosome structures contained two major polypeptides of 37 and 83 kilodalton relative molecular weights that were absent from the nuclear matrix preparations. A few polypeptides with the same or very similar electrophoretic mobilities were found in the residual structures of both the nuclei and the chromosomes.     

In vivo and in vitro interaction of high and low molecular weight single-chain urokinase-type plasminogen activator with rat liver cells.

The plasma clearance and the interaction of high (HMW) and low (LMW) molecular weight single-chain urokinase-type plasminogen activator (scu-PA) with rat liver cells was determined. 125I-Labeled HMW- and LMW-scu-PA were rapidly cleared from plasma with a half-life of 0.45 min and a maximal liver uptake of 55% of the injected dose. Liver uptake of scu-PA was mediated by parenchymal cells. Excess of unlabeled HMW-scu-PA reduced the liver uptake of 125I-HMW-scu-PA strongly. In vivo liver degradation of scu-PA was reduced by inhibitors of the lysosomal pathway. A high affinity binding site (Kd 45 nM, Bmax 1.7 pmol/mg cell protein) for both HMW- and LMW-scu-PA was determined on isolated parenchymal liver cells. Cross-competition binding studies showed that LMW- and HMW-scu-PA bind to the same site. Tissue-type plasminogen activator, mannose- or galactose-terminated glycoproteins did not affect the scu-PA binding to parenchymal liver cells. It is concluded that LMW- and HMW-scu-PA are taken up in the liver by a common, newly identified recognition site on parenchymal liver cells and are subsequently degraded in the lysosomes. It is suggested that this site is important for the regulation of the turnover of scu-PA.     

Nuclear matrix and chromosome scaffold preparations of in vitro cultured bovine liver cells have two proteins in common

Nuclear matrices and chromosome scaffolds of in vitro cultured bovine liver cells were prepared under conditions that preserve the specific binding of the DNA. Protein compositions were analysed by electrophoresis and peptide mapping. Two slightly acidic polypeptides of apparent molecular masses 47 and 53 kDa were present in nuclear matrix as well as chromosome scaffold preparations. The corresponding matrix and scaffold proteins had identical peptide maps. Their putative function in the spatial organization of the DNA during the cell cycle is considered.     

Malaria Burden and Artemisinin Resistance in the Mobile and Migrant Population on the Thai–Myanmar Border, 1999–2011: An Observational Study

Background

The Shoklo Malaria Research Unit has been working on the Thai–Myanmar border for 25 y providing early diagnosis and treatment (EDT) of malaria. Transmission of Plasmodium falciparum has declined, but resistance to artesunate has emerged. We expanded malaria activities through EDT and evaluated the impact over a 12-y period.

Methods and Findings

Between 1 October 1999 and 30 September 2011, the Shoklo Malaria Research Unit increased the number of cross-border (Myanmar side) health facilities from two to 11 and recorded the number of malaria consultations. Changes in malaria incidence were estimated from a cohort of pregnant women, and prevalence from cross-sectional surveys. In vivo and in vitro antimalarial drug efficacy were monitored. Over this period, the number of malaria cases detected increased initially, but then declined rapidly. In children under 5 y, the percentage of consultations due to malaria declined from 78% (95% CI 76–80) (1,048/1,344 consultations) to 7% (95% CI 6.2–7.1) (767/11,542 consultations), p<0.001. The ratio of P. falciparum/P. vivax declined from 1.4 (95% CI 1.3–1.4) to 0.7 (95% CI 0.7–0.8). The case fatality rate was low (39/75,126; 0.05% [95% CI 0.04–0.07]). The incidence of malaria declined from 1.1 to 0.1 episodes per pregnant women-year. The cumulative proportion of P. falciparum decreased significantly from 24.3% (95% CI 21.0–28.0) (143/588 pregnant women) to 3.4% (95% CI 2.8–4.3) (76/2,207 pregnant women), p<0.001. The in vivo efficacy of mefloquine-artesunate declined steadily, with a sharp drop in 2011 (day-42 PCR-adjusted cure rate 42% [95% CI 20–62]). The proportion of patients still slide positive for malaria at day 3 rose from 0% in 2000 to reach 28% (95% CI 13–45) (8/29 patients) in 2011.

Conclusions

Despite the emergence of resistance to artesunate in P. falciparum, the strategy of EDT with artemisinin-based combination treatments has been associated with a reduction in malaria in the migrant population living on the Thai–Myanmar border. Although limited by its observational nature, this study provides useful data on malaria burden in a strategically crucial geographical area. Alternative fixed combination treatments are needed urgently to replace the failing first-line regimen of mefloquine and artesunate. Please see later in the article for the Editors'' Summary     

Effect of temperature on seed production in the invasive grass Glyceria maxima (Hartm.) Holmb. (Poaceae) in South Africa

Temperature is one of the main factors that determine sexual reproduction in terrestrial and emergent aquatic plant species. The effect of temperature on sexual reproduction and seed production of Glyceria maxima (Hartm.) Holmb. in the southern hemisphere is unknown. Glyceria maxima collections in February 2010 at three isolated infestations in KwaZulu-Natal failed to yield a single seed, only empty panicles. Laboratory experiments showed that vernalisation had no consistent effect on seed production. Field- and laboratory-grown plants produced seeds in the 2010/2011 season, because of having sufficient time at optimum temperatures required for seed production (1 491 and 1 585 hours, respectively), compared to a shorter period (1 352 hours) of suitable temperatures during the 2009/2010 growing season. An inadequate period of optimum temperatures (15–25°C) during seed production resulted in the lack of seeds in the field in the 2009/2010 growing season. This study showed that temperature and duration of exposure thereto during the seed-production period play vital roles in G. maxima sexual reproduction.     

Ground wētā in vines of the Awatere Valley,Marlborough: biology,density and distribution

The endemic New Zealand ground wētā (Hemiandrus sp. ‘promontorius’) has a Naturally Uncommon conservation status. This is because of the paucity of information on its density and distribution. Here, the biology, density and distribution of a population of this wētā found in and around vineyards in the Awatere Valley, Marlborough was studied. Wētā density was assessed in vineyards, paddocks and shrublands in this valley. Soil moisture, penetration resistance, pH and organic matter were recorded at locations with and without wētā. Wētā density in vineyards was significantly higher than in either paddocks or shrub habitats. In vineyards, the density of this insect was significantly higher under-vines than in the inter-rows. Higher numbers of this wētā were found in moist soils that required lower force to burrow. Females laid an average of 55 eggs between March and April, which hatched in September. These findings highlight the intersection between agriculture and conservation.     

Localization of sequences regulating ancestral and acquired sites of esterase6 activity in Drosophila melanogaster

We have broadly defined the DNA regions regulating esterase6 activity in several life stages and tissue types of D. melanogaster using P- element-mediated transformation of constructs that contain the esterase6 coding region and deletions or substitutions in 5' or 3' flanking DNA. Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and the primary sequences regulating its activity lie between -171 and -25 bp relative to the translation initiation site: deletion of these sequences decrease activity approximately 20-fold. Hemolymph activity is also modulated by four other DNA regions, three of which lie 5' and one of which lies 3' of the coding region. Of these, two have positive and two have negative effects, each of approximately twofold. Esterase6 activity is present also in two male reproductive tract tissues; the ejaculatory bulb, which is another ancestral activity site, and the ejaculatory duct, which is a recently acquired site within the melanogaster species subgroup. Activities in these tissues are at least in part independently regulated: activity in the ejaculatory bulb is conferred by sequences between -273 and -172 bp (threefold decrease when deleted), while activity in the ejaculatory duct is conferred by more distal sequences between -844 and -614 bp (fourfold decrease when deleted). The reproductive tract activity is further modulated by two additional DNA regions, one in 5' DNA (-613 to -284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to +2731 bp; threefold decrease when deleted) that probably overlaps the adjacent esteraseP gene. Collating these data with previous studies suggests that expression of EST6 in the ancestral sites is mainly regulated by conserved proximal sequences while more variable distal sequences regulate expression in the acquired ejaculatory duct site.      

1-Thio-beta-D-galactofuranosides: synthesis and evaluation as beta-D- galactofuranosidase inhibitors

Beta-D-galactofuranosidase is a good chemotherapeutic target for the design of inhibitors, since beta-D-galactofuranose is a constituent of important parasite glycoconjugates but is not present in the host mammals. With this aim, we have synthesized for the first time alkyl, benzyl and aryl 1-thio-beta-D-galactofuranosides by condensation of penta-O-benzoyl-alpha,beta-D-galactofuranose with the corresponding thiols, in the presence of SnCl4as catalyst. The complete chemical and spectroscopical characterization of these compounds showed that the reaction was stereoselective. Debenzoylation with sodium methoxide afforded the beta-S-galactofuranosides in high yield. The thioglycosides were tested as inhibitors of the beta-D- galactofuranosidase of Penicillium fellutanum, using for the first time 4-nitrophenyl-beta-D-galactofuranoside as chromogenic substrate. The 4- aminophenyl-1-thio-beta-D-galactofuranoside, obtained by catalytic hydrogenation of the nitrophenyl derivative, was the best inhibitor being then an adequate ligand for the preparation of an affinity phase aimed at the isolation of beta-d-galactofuranosidases from different sources. Also the inhibitory activity of d-galactono-1, 4-lactone was shown.