Smad3 mediates the TGF-beta-induced contraction of type I collagen gels by mouse embryo fibroblasts

TGF-beta signals through TGF-beta receptors and Smad proteins. TGF-beta also augments fibroblast-mediated collagen gel contraction, an in vitro model of connective tissue remodeling. To investigate the importance of Smad2 or Smad3 in this augmentation process, embryo-derived fibroblasts from mice lacking expression of Smad2 or Smad3 genes were cast into native type I collagen gels. Fibroblast-populated gels were then released into 0.2% FCS-DMEM alone or with recombinant human TGF-beta1, beta2, beta3, or recombinant rat PDGF-BB. Gel contraction was determined using an image analyzer. All three isoforms of TGF-beta significantly augmented contraction of collagen gels mediated by fibroblasts with genotypes of Smad2 knockout (S2KO), Smad2 wildtype (S2WT), and Smad3 wildtype (S3WT), but not Smad3 knockout (S3KO) mice. PDGF-BB augmented collagen gel contraction by all fibroblast types. These results suggest that expression of Smad3 but not Smad2 may be critical in TGF-beta augmentation of fibroblast-mediated collagen gel contraction. Thus, the Smad3 gene could be a target for blocking contraction of fibrotic tissue induced by TGF-beta.     

Deletion of all Cochliobolus heterostrophus monofunctional catalase-encoding genes reveals a role for one in sensitivity to oxidative stress but none with a role in virulence

The genome of the maize pathogen Cochliobolus heterostrophus encodes three unlinked monofunctional catalase-encoding (CAT) genes that singly or in combination could offer protection against the harmful effects of oxidative stress. Phylogenetic analysis placed the CAT2 and CAT3 proteins in a cluster with large subunit catalases (CAT3 has a secretory signal sequence and was grouped with known secreted catalases), whereas CAT1 clustered with small subunit catalases. Single, double, and triple cat mutants were created and screened for sensitivity to hydrogen peroxide and altered virulence on maize. All mutants deficient in CAT3 had enhanced sensitivity to hydrogen peroxide, as compared with wild type or with mutants deficient in CAT1, CAT2, or both. All catalase-deficient mutants had normal virulence to maize. Thus, the secreted CAT3 protein protects the fungus from oxidative stress during vegetative growth, but members of this enzyme family, alone or in combination, are not essential for virulence.     

Deracemization of an axially chiral biphenylic derivative as a tool for investigating chiral recognition in self-assemblies

Two diastereomeric cationic surfactants derived from L-proline, in which the second chiral center is a quaternary nitrogen, have been separated and fully characterized. The recognition properties of the aggregates formed by the two diastereomeric surfactants have been investigated by circular dichroism and (1)H NMR through deracemization of racemic 2-carboxy-2'-dodecyloxy-6-nitrobiphenyl.     

Interaction of sertraline with Candida species selectively attenuates fungal virulence in vitro

This study investigated whether the interaction between isolates of Candida albicans (n=7), Candida parapsilosis (n=3), Candida krusei (n=2), Candida dubliniensis (n=1) and sertraline, a typical selective serotonin reuptake inhibitor, alters candidal virulence. Sertraline treatment of Candida spp. significantly (P<0.05) affected hyphal elongation, phospholipase activity, production of secreted aspartyl proteinases and fungal viability. In addition, monocyte-derived macrophages (MDMs) treated with sertraline reduced inhibition of blastoconidia germination in comparison to MDMs alone. In conclusion, our findings suggest that the interaction between sertraline and Candida spp. may also diminish the virulence properties of this fungal pathogen in vivo.     

Synthesis of 3-phenylpyrazolo[4,3-b]pyridines via a convenient synthesis of 4-amino-3-arylpyrazoles and SAR of corticotropin-releasing factor receptor type-1 antagonists

3-Phenylpyrazolo[4,3-b]pyridines were synthesized via a cyclization of 4-amino-3-phenylpyrazoles 11-13 with ethyl acetoacetate. These compounds were found to be potent CRF(1) antagonists. The 2-alkylpyrazolo[4,3-b]pyridines were more polar but less active than the corresponding 1-alkyl-isomers.     

Linkage-dependent gene flow in a house mouse chromosomal hybrid zone

In the alpine valley of Valtellina there are two Robertsonian chromosomal races of house mouse, the Poschiavo (POS: 2n = 24-26) characterized by metacentric 8.12 and acrocentrics 2 and 10 and the Upper Valtellina (UV: 2n = 22-24) characterized by metacentrics 2.8 and 10.12. The races inhabit separate villages in the valley except in Sommacologna and Sondalo, where they both occur together with hybrids. A total of 179 mice from 16 villages were typed at 13 microsatellite loci. Seven of these loci were localized close to the centromeres of chromosomes 10 and 12, with the prediction that these regions on the race-specific chromosomes would be the most likely to experience a barrier to gene flow. The remaining six loci were localized at the telomeres of chromosomes 10 and 12 and at the centromeres of chromosomes that do not differ between the races. Substantial differences in allelic frequencies were found between the villages with POS and UV races at five of the loci at the centromeres of chromosomes 10 and 12 but at none of the other loci. These differences were not found to distinguish the two races in Sommacologna and Sondalo. Therefore, the centromeric regions of race-specific chromosomes do appear to experience a barrier to gene flow, although this can break down under intense interbreeding between the races. These results are considered in the context of Harrison's (1990) concept of the semipermeability of hybrid zones to gene exchange and in relation to parapatric speciation.     

A new blood coagulation inhibitor from the snake Bothrops jararaca plasma: isolation and characterization

A novel thrombin inhibitor, Bothrops jararaca inhibitor (BjI), has been identified and purified from B. jararaca snake blood by two anionic chromatographic steps. Purified BjI showed two polypeptide chains with molecular masses of 109 and 138 kDa, by SDS-PAGE in reducing conditions. On the other hand, in nonreducing conditions the molecular masses were 150 and 219 kDa, suggesting that the polypeptide chain 109 kDa can be a dimer form linked by disulfide bond. However, the native BjI shows a molecular mass higher than 1000 kDa by gel filtration chromatography, indicating the need of a quaternary structure formation for the blood coagulation inhibition. BjI is a specific thrombin coagulant activity inhibitor that does not affect other thrombin functions, such as: amidolytic and platelet aggregation activities. BjI is not an antithrombin-like inhibitor. Fibrinogen and heparin competition ELISA assays with BjI and thrombin showed that fibrinogen does not interfere in the BjI and thrombin binding, however, heparin interferes in BjI and thrombin interaction, suggesting that BjI binds to heparin site or other sites close to it. Our findings indicate that BjI is an exosite binding thrombin inhibitor, specific upon coagulant activity thrombin inhibitor, without any anti-platelet aggregation activity.