Configurations of germinal vesicle (GV) chromatin in the goat differ from those of other species

Configuration of germinal vesicle (GV) chromatin has been studied and found correlated with the developmental competence of oocytes in several mammalian species. A common feature in the configuration of GV chromatin in the species studied so far is that the diffuse chromatin (the so called "NSN" pattern) condenses into a perinucleolar ring (the so called "SN" configuration) with follicular growth. However, no study has been published on the configuration of GV chromatin in the goat. Nor is it known whether the perinucleolar ring of condensed chromatin (CC) in an oocyte represents a step toward final maturation or atresia. Changes in configurations of GV chromatin and RNA synthesis during goat oocyte growth, atresia and maturation in vivo and in vitro were investigated in this study. Based on both the size of nucleoli and the degree of chromatin condensation, the GV chromatin of goat oocytes was classified into GV1 characterized by large nucleoli and diffuse chromatin, GV2 with medium-sized nucleoli and condensed net-like (GV2n) or clumped (GV2c) chromatin, GV3 with small nucleoli and net-like (GV3n) or clumped (GV3c) chromatin, and GV4 with no nucleolus but clumped chromatin. The results showed that (i) the configurations of GV chromatin in the goat differ from those of other species in that the chromatin did not condense into a perinucleolar ring; (ii) most of the goat oocytes are synchronized at the GV3n configuration before GVBD; (iii) the GVn pattern might represent a healthy state, but the GVc an atretic state; (iv) in both goats and mice, the GC-specific (Chromomycin A3, CMA3) and the AT-specific (Hoechst 33342) fluorochromes followed the same pattern of distribution in GV chromatin; (v) the nucleolar size decreased significantly with oocyte growth and maturation in vivo and in vitro; and (vi) goat oocytes began GVBD at 8 hr and had completed it by 20 hr after onset of estrus. The peculiar configuration of GV chromatin of goat oocytes can be a useful model for studies of morphological and functional changes of different nuclear compartments during the cell cycle and cell differentiation, and the functional differentiation between GV3n and GV3c might be used for reference to the question whether the "SN" configuration in other species inclines toward ovulation or atresia.     

Role of K-ras and Pten in the development of mouse models of endometriosis and endometrioid ovarian cancer

Epithelial ovarian tumors present a complex clinical, diagnostic and therapeutic challenge because of the difficulty of early detection, lack of known precursor lesions and high mortality rates. Endometrioid ovarian carcinomas are frequently associated with endometriosis, but the mechanism for this association remains unknown. Here we present the first genetic models of peritoneal endometriosis and endometrioid ovarian adenocarcinoma in mice, both based on the activation of an oncogenic K-ras allele. In addition, we find that expression of oncogenic K-ras or conditional Pten deletion within the ovarian surface epithelium gives rise to preneoplastic ovarian lesions with an endometrioid glandular morphology. Furthermore, the combination of the two mutations in the ovary leads to the induction of invasive and widely metastatic endometrioid ovarian adenocarcinomas with complete penetrance and a disease latency of only 7 weeks. The ovarian cancer model described in this study recapitulates the specific tumor histomorphology and metastatic potential of the human disease.     

Identifying time-lagged gene clusters using gene expression data

MOTIVATION: Analysis of gene expression data can provide insights into the time-lagged co-regulation of genes/gene clusters. However, existing methods such as the Event Method and the Edge Detection Method are inefficient as they compare only two genes at a time. More importantly, they neglect some important information due to their scoring criterian. In this paper, we propose an efficient algorithm to identify time-lagged co-regulated gene clusters. The algorithm facilitates localized comparison and processes several genes simultaneously to generate detailed and complete time-lagged information for genes/gene clusters. RESULTS: We experimented with the time-series Yeast gene dataset and compared our algorithm with the Event Method. Our results show that our algorithm is not only efficient, but also delivers more reliable and detailed information on time-lagged co-regulation between genes/gene clusters. AVAILABILITY: The software is available upon request. CONTACT: jiliping@comp.nus.edu.sg SUPPLEMENTARY INFORMATION: Supplementary tables and figures for this paper can be found at http://www.comp.nus.edu.sg/~jiliping/p2.htm.     

Advancing chemistry and biology through diversity-oriented synthesis of natural product-like libraries

Natural products provide the inspiration for a variety of strategies used in the diversity-oriented synthesis of novel small-molecule libraries. These libraries can be based on core scaffolds from individual natural products, specific substructures found across a class of natural products, or general structural characteristics of natural products. An increasing body of evidence supports the effectiveness of these strategies for identifying new biologically active molecules. Moreover, these efforts have led to significant advances in synthetic organic chemistry. Larger-scale evaluation of these approaches is on the horizon, using screening data that will be made publicly available in the new PubChem database.     

Isolation by distance and post-glacial range expansion in the rough-skinned newt, Taricha granulosa

Allozymes and mitochondrial DNA sequences were used to examine the phylogeographical history of the rough-skinned newt, Taricha granulosa, in western North America. Nineteen populations were analysed for allozyme variation at 45 loci, and 23 populations were analysed for cytochrome b sequence variation. Both data sets agree that populations in the southern part of the range are characterized by isolation by distance, whereas northern populations fit the expectations of a recent range expansion. However, the northern limit of isolation by distance (and the southern limit of range expansion) is located in Oregon State by the mtDNA data, and in Washington State by the allozyme data. Nevertheless, both data sets are consistent with the known Pleistocene history of western North America, with phylogenetically basal populations in central and northern California, and a recent range expansion in the north following the retreat of the Cordilleran ice sheet 10,000 years ago. Additionally, a population in Idaho, previously considered introduced from central California based on morphometric analyses, possesses a distinct mtDNA haplotype, suggesting it could be native. The relevance of these results for Pacific Northwest biogeography is discussed.     

The iron chelator desferrioxamine inhibits atherosclerotic lesion development and decreases lesion iron concentrations in the cholesterol-fed rabbit

Several epidemiological studies have suggested that increased iron stores are associated with increased atherosclerotic events. In order to test the hypothesis that decreasing the vascular level of iron slows lesion growth, we examined the effects of the iron chelator Desferal (72 mg/kg/day, 5 days/week) on atherosclerosis and lesion iron content in cholesterol-fed New Zealand White rabbits. Rabbits were fed with a 1% w/w cholesterol diet for either 8 weeks (and for the last 5 weeks injected daily with Desferal) or 12 weeks (and for the last 9 weeks injected with Desferal). Controls were injected with saline. A significant reduction in average lesion area (p = 0.038) was observed in the 12-week treated animals compared with the 12-week controls. The average lesion iron level of the 12-week treated animals (58 ppm dry wt) was also significantly lower (p = 0.030) than in 12-week control animals (95 ppm dry wt), as measured using nuclear microscopy with the combination of scanning transmission ion microscopy, Rutherford back-scattering spectroscopy, and particle-induced X-ray emission. No reduction in lesion area or iron content was observed in the 8-week treated animals compared with controls, and no change in lesion zinc concentration was observed for either group. Our data strengthen the concept that iron contributes to the early stages of the development of atherosclerosis.     

Identification of an integral plasma membrane pool of protein kinase C in mammalian tissues and cells

Protein kinase C (PKC) is a family of serine/threonine protein kinases that are pivotal in cellular regulation. Since its discovery in 1977, PKCs have been known as cytosolic and peripheral membrane proteins. However, there are reports that PKC can insert into phospholipids vesicles in vitro. Given the intimate relationship between the plasma membrane and the activation of PKC, it is important to determine whether such "membrane-inserted" form of PKC exists in mammalian cells or tissues. Here, we report the identification of an integral plasma membrane pool for all the 10 PKC isozymes in vivo by their ability to partition into the detergent-rich phase in Triton X-114 phase partitioning, and by their resistance to extractions with 0.2 M sodium carbonate (pH 11.5), 2 M urea and 2 M sodium chloride. The endogenous integral membrane pool of PKC in mouse fibroblasts is found to be acutely regulated by phorbol ester or diacylglycerol, suggesting that this pool of PKC may participate in cellular processes known to be regulated by PKC. At least for PKC(alpha), the C2-V3 region at the regulatory domain of the kinase is responsible for membrane integration. Further exploration of the function of this novel integral plasma membrane pool of PKC will not only shed new light on molecular mechanisms underlying its cellular functions but also provide new strategies for pharmaceutical modulation of this important group of kinases.     

Zinc Casting and Recycling (8 pp)

Aim, Scope and Background Metal die casting is a highly energy-intensive industry. In addition to that, the production of primary zinc by smelting consumes huge amounts of energy as well as generates many types of pollution. This paper uses LCA to investigate the environmental performance of a zinc cast product. The areas of environmental concern are focused on the direct and indirect air emissions that arise from the Zinc Smelting, Casting and Recycling, as well as transportation. Main Features The LCA case study employs a cradle-to-gate approach, which starts with the purchasing of primary zinc from abroad, casting, inspection, and ends when the scrap metal is sent back for recycling by truck. Based on a “generic” zinc casting product, the objective of the LCA was to compare the air emissions from the material cycle due to: i) the increased content of recycled metal in the final cast product; and ii) the choice of selecting between two Remelters (A and B), the first located near the company and the other in a neighbouring country, to send zinc scrap for recycling. The LCA SimaPro software (version 5.0) Eco-indicator “99 method is used to perform an impact assessment for Climate Change, Acidification, Ecotoxicity, Respiratory Inorganics, and Respiratory Organics was performed. Results The results from direct (process) and indirect (power plants) air emissions confirmed that the major air pollution occurs during Zinc Smelting, that is up to approximately 65–70%. Although an increase in recycling rates resulted in higher levels of air pollution from transportation as well as heavy metals from dross, these two issues were insignificant compared to the huge amount of energy consumed for primary metal production. Based on air pollution from transportation alone, a significant reduction of greenhouse gases and VOCs of 90% each was appreciated when Remelter A was selected. Conclusion The results verified that efforts to recycle zinc and consume the material in a more sustainable manner have become highly important. Also, a second LCA investigation that was made to compare zinc cast products that consists of: 100% primary zinc, mixtures of 50–50% and 40–60% primary-to-recycled zinc, and finally 100% recycled zinc; further emphasized the need for using recycled metal, as opposed to using primary metal.     

Synthesis and evaluation of bifunctional nitrocatechol inhibitors of pig liver catechol-O-methyltransferase

Bifunctional compounds were tested in vitro as potential inhibitors of pig liver catechol-O-methyltransferase (COMT) with respect to the catechol substrate 4-[(3,4-dihydroxyphenyl)azo]benzenesulfonate. The bifunctional compounds were a composite of either two nitrocatechols or one nitrocatechol and one phenol, linked by amide bonds to a spacer unit comprising two to five methylene groups. The unsymmetrical compounds N-[2-(4-hydroxybenzoylamine)ethyl]-3,4-dihydroxy-5-nitrobenzamide], N-[3-(4-hydroxybenzoyl-amine)propyl]-3,4-dihydroxy-5-nitrobenzamide] and N-[5-(4-hydroxybenzoylamine)pentyl]-3,4-dihydroxy-5-nitrobenzamide] demonstrated strong inhibitory action against COMT with K(i) values in the 100 nM range. In comparison, the monofunctional nitrocatechol analogues of these compounds had K(i) values that were significantly higher.