Deletions within the Mouse β-Globin Locus Control Region Preferentially Reduce β Globin Gene Expression

The mouse β-globin gene cluster is regulated, at least in part, by a locus control region (LCR) composed of several developmentally stable DNase I hypersensitive sites located upstream of the genes. In this report, we examine the level of expression of the β^min and β^maj genes in adult mice in which HS2, HS3, or HS5,6 has been either deleted or replaced by a selectable marker via homologous recombination in ES cells. Primer extension analysis of RNA extracted from circulating reticulocytes and HPLC analysis of globin chains from peripheral red blood cells revealed that all mutations that reduce the overall output of the locus preferentially decrease β^min expression over β^maj. The implications of these findings for the mechanism by which the LCR controls expression of the β^maj and β^min promoters are discussed.     

Description of the Nymphs and Eggs of Acentrella almohades sp. n. from Morocco and Southern Spain (Ephemeroptera: Baetidae)

The nymph and egg of Acentrella almohades sp. n. are described and illustrated on the basis of material collected in southern Spain (in the upper reaches of the Guadalquivir River Basin) and Morocco (Rif Mountains and Atlas Mountains). Features distinguishing the new species from other European species are discussed and keyed.     

Preparative scale expression of membrane proteins in Escherichia coli-based continuous exchange cell-free systems

Cell-free expression is emerging as a prime method for the rapid production of preparative quantities of high-quality membrane protein samples. The technology facilitates easy access to large numbers of proteins that have been extremely difficult to obtain. Most frequently used are cell-free systems based on extracts of Escherichia coli cells, and the reaction procedures are reliable and efficient. This protocol describes the preparation of all essential reaction components such as the E. coli cell extract, T7 RNA polymerase, DNA templates as well as the individual stock solutions. The setups of expression reactions in analytical and preparative scales, including a variety of reaction designs, are illustrated. We provide detailed reaction schemes that allow the preparation of milligram amounts of functionally folded membrane proteins of prokaryotic and eukaryotic origin in less than 24 h.     

Sex differences in political leadership in an egalitarian society

We test the contribution of sex differences in physical formidability, education, and cooperation to the acquisition of political leadership in a small-scale society. Among forager-farmers from the Bolivian Amazon, we find that men are more likely to exercise different forms of political leadership, including verbal influence during community meetings, coordination of community projects, and dispute resolution. We show that these differences in leadership are not due to gender per se but are associated with men's greater number of cooperation partners, greater access to schooling, and greater body size and physical strength. Men's advantage in cooperation partner number is tied to their participation in larger groups and to the opportunity costs of women's intrahousehold labor. We argue these results highlight the mutual influence of sexual selection and the sexual division of labor in shaping how women and men acquire leadership.     

Protective and therapeutic effects of resveratrol on acetic acid-induced gastric ulcer

Sprague Dawley rats of both sexes were injected with either saline or RVT (10 mg/kg) either before or after acetic acid ulcer induction and decapitated 3, 5 or 10 days after ulcer. In the saline-treated ulcer groups, macroscopically evident ulcers were observed, while RVT-pretreated or RVT-treated groups had lower macroscopic ulcer scores. Likewise, the microscopic damage scores were lower for the RVT-administered groups. Gastric myeloperoxidase activity, malondialdehyde, collagen and tumour necrosis factor-alpha levels, as well as luminol- and lucigenin-enhanced chemiluminescence levels that were elevated in the saline-administered ulcer groups, were depressed with both RVT-pretreatment and RVT-treatment. Moreover, depleted glutathione levels in the ulcer groups were increased back to control levels by both pre- and post-treatments of RVT. Results demonstrate that resveratrol has both protective and therapeutic effects on oxidative gastric damage by suppressing pro-inflammatory cascades, including the activation of pro-inflammatory cytokines, accumulation of neutrophils and release of oxygen-derived free radicals.     

Enhancing white lupin (Lupinus albus L.) adaptation to calcareous soils through selection of lime-tolerant plant germplasm and Bradyrhizobium strains

Aims

This study aimed to determine whether white lupin adaptation to moderately calcareous soils could be enhanced by lime-tolerant plants and Bradyrhizobium strains.

Methods

Fourteen landraces from Italy, Morocco and Egypt and some cultivars were grown in moderate-lime (ML) and low-lime (LL) soil with each of two inoculants, one commercial and one including three Bradyrhizobium strains well-nodulating under ML soil (isolated from other lupin species). Grain yield and above-ground biomass were assessed in large artificial environments that mimicked field conditions. Shoot, root and nodulation traits at onset of flowering were studied in a pot experiment.

Results

ML soil severely reduced plant yield, growth and nodulation but increased the harvest index relative to LL. Top-yielding genotypes for grain yield displayed significant rank inversion across soil types (P < 0.05). Lime-tolerant genotypes reduced their nodulation in ML soil less than limesusceptible ones. Some landraces outperformed the reference lime-tolerant cultivar Giza 1 in ML soil. One Italian landrace had a lime-tolerant response across agricultural locations. The Moroccan inoculant provided greater nodulation, more shoot residues but similar grain yield in ML soil, and less grain and shoot residues in LL soil, compared with the commercial inoculant.

Conclusions

Lupin adaptation to ML soil can be improved mainly through selection of lime-tolerant plants.     

Conservation and multivariate analysis utility in characterization of ecogegraphical relationships of Trifolium and Lotus species

The maintenance of species in an environment and the durability of rangeland and fallow improvement depend on the choice of populations used. The study of abundance and the relationship between the natural distribution of spontaneous legumes species of forage and/or pastoral interest and environmental factors is an important step for an adequate utilization of local genetic resources. Collection of annual Trifolium species and the genus of Lotus were conducted at 45 sites in Morocco in May/June 2004. Ecogeographical information was recorded at each site. Twelve species of annual Trifolium and two species of Lotus were identified. Most prolific were T. tomentosum and L. corniculatus. A principal components analysis and canonical variate analysis were conducted to group the sites, using the ecogeographical variables collected at each site. The variables that were found to be most important in grouping the sites were mean coldest month temperature, mean hottest month temperature, mean annual rainfall, latitude, longitude and soil pH. None of the species identified were limited to only one ecogeographical group.     

Absence of Siglec-H in MCMV Infection Elevates Interferon Alpha Production but Does Not Enhance Viral Clearance

Plasmacytoid dendritic cells (pDCs) express the I-type lectin receptor Siglec-H and produce interferon α (IFNα), a critical anti-viral cytokine during the acute phase of murine cytomegalovirus (MCMV) infection. The ligands and biological functions of Siglec-H still remain incompletely defined in vivo. Thus, we generated a novel bacterial artificial chromosome (BAC)-transgenic “pDCre” mouse which expresses Cre recombinase under the control of the Siglec-H promoter. By crossing these mice with a Rosa26 reporter strain, a representative fraction of Siglec-H⁺ pDCs is terminally labeled with red fluorescent protein (RFP). Interestingly, systemic MCMV infection of these mice causes the downregulation of Siglec-H surface expression. This decline occurs in a TLR9- and MyD88-dependent manner. To elucidate the functional role of Siglec-H during MCMV infection, we utilized a novel Siglec-H deficient mouse strain. In the absence of Siglec-H, the low infection rate of pDCs with MCMV remained unchanged, and pDC activation was still intact. Strikingly, Siglec-H deficiency induced a significant increase in serum IFNα levels following systemic MCMV infection. Although Siglec-H modulates anti-viral IFNα production, the control of viral replication was unchanged in vivo. The novel mouse models will be valuable to shed further light on pDC biology in future studies.     

A Chinese hamster ovarian cell line imports cholesterol by high density lipoprotein degradation

Plasma high density lipoprotein (HDL) is inversely associated with the development of atherosclerosis. HDL exerts its atheroprotective role through involvement in reverse cholesterol transport in which HDL is loaded with cholesterol at the periphery and transports its lipid load back to the liver for disposal. In this pathway, HDL is not completely dismantled but only transfers its lipids to the cell. Here we present evidence that a Chinese hamster ovarian cell line (CHO7) adapted to grow in lipoprotein-deficient media degrades HDL and concomitantly internalizes HDL-derived cholesterol. Delivery of HDL cholesterol to the cell was demonstrated by a down-regulation of cholesterol biosynthesis, an increase in total cellular cholesterol content and by stimulation of cholesterol esterification after HDL treatment. This HDL degradation pathway is distinct from the low density lipoprotein (LDL) receptor pathway but also degrades LDL. 25-Hydroxycholesterol, a potent inhibitor of the LDL receptor pathway, down-regulated LDL degradation in CHO7 cells only in part and did not down-regulate HDL degradation. Dextran sulfate released HDL bound to the cell surface of CHO7 cells, and heparin treatment released protein(s) contributing to HDL degradation. The involvement of heparan sulfate proteoglycans and lipases in this HDL degradation was further tested by two inhibitors genistein and tetrahydrolipstatin. Both blocked HDL degradation significantly. Thus, we demonstrate that CHO7 cells degrade HDL and LDL to supply themselves with cholesterol via a novel degradation pathway. Interestingly, HDL degradation with similar properties was also observed in a human placental cell line.