Reconstruction of human evolutionary tree using polymorphic autosomal microsatellites

Allelic frequencies of 182 tri- and tetra-autosomal microsatellites were used to examine phylogenetic relationships among 19 extant human populations. In particular, because the languages of the Basques and Hunza Burusho have been suggested to have an ancient relationship, this study sought to explore the genetic relationship between these two major language isolate populations and to compare them with other human populations. The work presented here shows that the microsatellite allelic diversity and the number of unique alleles were highest in sub-Saharan Africans. Neighbor-joining trees based on genetic distances and principal component analyses separated populations from different continents, and are consistent with an African origin for modern humans. For the first time, with biparentally transmitted markers, the microsatellite tree also shows that the San are the first branch of the human tree before the branch leading to all other Africans. In contrast to an earlier study, these results provided no evidence of a genetic relationship among the two language isolate groups. Genetic relationships, as ascertained by these microsatellites, are dictated primarily by geographic proximity rather than by remote linguistic origin, Mantel test, R(0) = 0.484, g = 3.802 (critical g value = 1.645; P = 0.05).     

In vivo culture of embryos in the immature mouse oviduct

In-vitro culture of mammalian preimplantation embryos is associated with subsequent decreased viability. This phenomenon is more pronounced with the domestic species embryos as culture conditions are at present unable to sustain cleavage of early preimplantation embryos for more than one or two cell divisions. In this study, the immature mouse oviduct is shown to be capable of supporting cleavage and morphological development of rabbit and porcine embryos. The immature mouse oviduct was shown to be comparable to in vitro culture as 76% and 60% of the transferred zygotes developed to the morula stage after 2 and 3 d respectively. The porcine zygotes, however, failed to develop beyond the 4-cell stage in either the immature mouse oviduct or in vitro. Porcine morula showed better tolerance of the oviduct environment and when recovered after 2 d contained an average of 64 cells, which was significantly more than in in vitro cultured morulae (40 cells). Early porcine blastocysts transferred to the mouse oviduct had over a two-fold increase in cell division (104 cells) over comparable blastocysts grown in vitro (57 cells). The immature mouse oviduct is, therefore, a potential surrogate environment for short-term storage of embryos of other species.     

Interrelated modulation of endothelial function in Behcet's disease by clinical activity and corticosteroid treatment

Corticosteroids are commonly used in empirical treatment of Behçet''s disease (BD), a systemic inflammatory condition associated with reversible endothelial dysfunction. In the present study we aimed to dissect the effects of clinical disease activity and chronic or short-term corticosteroid treatment on endothelial function in patients with BD. In a case-control, cross-sectional study, we assessed endothelial function by endothelium dependent flow mediated dilatation (FMD) at the brachial artery of 87 patients, who either were or were not receiving chronic corticosteroid treatment, and exhibiting variable clinical disease activity. Healthy individuals matched for age and sex served as controls. Endothelial function was also assessed in a prospective study of 11 patients before and after 7 days of treatment with prednisolone given at disease relapse (20 mg/day). In the cross-sectional component of the study, FMD was lower in patients than in control individuals (mean ± standard error: 4.1 ± 0.4% versus 5.7 ± 0.2%, P = 0.003), whereas there was a significant interaction between the effects of corticosteroids and disease activity on endothelial function (P = 0.014, two-factor analysis of variance). Among patients with inactive BD, those who were not treated with corticosteroids (n = 33) had FMD comparable to that in healthy control individuals, whereas those treated with corticosteroids (n = 15) had impaired endothelial function (P = 0.023 versus the respective control subgroup). In contrast, among patients with active BD, those who were not treated with corticosteroids (n = 20) had lower FMD than control individuals (P = 0.007), but in those who were receiving corticosteroids (n = 19) the FMD values were comparable to those in control individuals. Moreover, FMD was significantly improved after 7 days of prednisolone administration (3.7 ± 0.9% versus 7.6 ± 1.4%, P = 0.027). Taken together, these results imply that although corticosteroid treatment may impair endothelial function per se during the remission phase of the inflammatory process, it restores endothelial dysfunction during active BD by counteracting the harmful effects of relapsing inflammation.     

Cre activity causes widespread apoptosis and lethal anemia during embryonic development

Cre-mediated excision of targeted loxP sites is widely used to delete or to activate gene expression in temporal or tissue-specific fashions. We examine three previously described cre alleles and find that Cre activity alone causes dramatic developmental defects, such as loss of hematopoietic activity and dramatically upregulated apoptosis in many embryonic tissues in two of these lines. These results demonstrate that cre expression generates spurious phenotypes that can confound genetics analyses. We also find that most recently published studies fail to include cre-positive controls, and thus may have attributed roles to a targeted gene, which were in reality partly or wholly due to Cre toxicity. This information will be critical in both evaluating previously published work using cre alleles and in designing future experiments.     

Fast sampling and quenching procedures for microbial metabolic profiling

A reliable quantification of intracellular concentrations of intermediates in microorganisms depends on a proper sampling procedure and the subsequent fast inactivation of metabolism via quenching. A single device integrating both operations was developed and simultaneously the quenching procedure on cells was assessed too, without finding negative effects on viability or metabolite leakage. Moreover, supported by an experimental design, the influences of process parameters in its dynamic operation were characterized and optimized. The novel in-situ rapid sampling and quenching apparatus can be employed on any laboratory glass fermenters accessible from the top of the bioreactor.     

Tbx4 is not required for hindlimb identity or post-bud hindlimb outgrowth

Tbx4 is a crucial gene in the initiation of hindlimb development and has been reported as a determinant of hindlimb identity and a presumptive direct regulator of Fgf10 in the limb. Using a conditional allele of Tbx4, we have ablated Tbx4 function before and after limb initiation. Ablation of Tbx4 before expression in the hindlimb field confirms its requirement for limb bud outgrowth. However, ablation of Tbx4 shortly after onset of expression in the hindlimb field, during limb bud formation, alters neither limb outgrowth nor expression of Fgf10. Instead, post-limb-initiation loss of Tbx4 results in reduction of limb core tissue and hypoplasia of proximal skeletal elements. Loss of Tbx4 during later limb outgrowth produces no limb defects, revealing a brief developmental requirement for Tbx4 function. Despite evidence from ectopic expression studies, our work establishes that loss of Tbx4 has no effect on hindlimb identity as assessed by morphology or molecular markers.