Early embryonic lethality in Bmp5;Bmp7 double mutant mice suggests functional redundancy within the 60A subgroup. (1/150)

Members of the BMP family of signaling molecules display a high conservation of structure and function, and multiple BMPs are often coexpressed in a variety of tissues during development. Moreover, distinct BMP ligands are capable of activating common pathways. Here we describe the coexpression of two members of the 60A subfamily of BMPs, Bmp5 and Bmp7, at a number of different sites in the embryo from gastrulation onwards. Previous studies demonstrate that loss of either Bmp5 or Bmp7 has negligible effects on development, suggesting these molecules functionally compensate for each other at early stages of embryonic development. Here we show this is indeed the case. Thus we find that Bmp5;Bmp7 double mutants die at 10.5 dpc and display striking defects primarily affecting the tissues where these factors are coexpressed. The present analysis also uncovers novel roles for BMP signaling during the development of the allantois, heart, branchial arches, somites and forebrain. Bmp5 and Bmp7 do not appear to be involved in establishing pattern in these tissues, but are instead necessary for the proliferation and maintenance of specific cell populations. These findings are discussed with respect to potential mechanisms underlying cooperative signaling by multiple members of the TGF-beta superfamily.  (+info)

Expression of matrix metalloproteinases during murine chorioallantoic placenta maturation. (2/150)

A large body of experimental evidence supports the participation of two groups of extracellular proteases, matrix metalloproteinases (MMPs), and plasminogen activators/plasmin, in tissue remodeling in physiological and pathological invasion. In the late mouse placenta, several tissue remodeling and cell invasion processes take place. Spongiotrophoblast migration into maternal decidua, as well as decidual extracellular matrix remodeling require the coordinated action of extracellular proteolytic enzymes. Via Northern and in situ hybridization, we have analyzed the spatio-temporal expression patterns of members of the MMP family (stromelysin-3, gelatinases A and B), as well as their inhibitors TIMP-1, -2 and -3 in late murine placenta (days 10.5 to 18.5 of gestation). Gelatinase activity in placental extracts was assessed by substrate zymography. Gelatinase A and stromelysin-3 were found to be prominently expressed in decidual tissue; shortly after midpregnancy, the decidual expression patterns of gelatinase A and stromelysin-3 became overlapping with each other, as well as with the expression domain of TIMP-2. On the other hand, gelatinase B transcripts were expressed only by trophoblast giant cells at day 10.5, and were downregulated at later stages. TIMP-1 and TIMP-3 transcripts were detected in decidual periphery at day 10.5, while later the expression was restricted to the endometrial stroma and spongiotrophoblasts, respectively. The areas of stromelysin-3 expression were the same (giant trophoblasts) or adjacent (decidua) to those where urokinase (uPA) transcripts were detected, suggesting a possible cooperation between these proteinases in placental remodeling. We generated mice doubly deficient for stromelysin-3 and uPA, and report here that these mice are viable and fertile. Furthermore, these animals do not manifest obvious placental abnormalities, thereby suggesting the existence of compensatory/redundant mechanisms involving other proteolytic enzymes. Our findings document the participation of MMPs and their inhibitors in the process of late murine placenta maturation, and warrant the characterization of other members of the MMP family, like membrane type-MMPs, in this process.  (+info)

Investigation of cell culture media infected with viruses by pyrolysis mass spectrometry: implications for bioaerosol detection. (3/150)

Mass spectrometry coupled with a pyrolysis inlet system was used to investigate media from cell cultures infected with viruses. Cell culture media is an intricate mixture of numerous chemical constituents and cells that collectively produce complicated mass spectra. Cholesterol and free fatty acids were identified and attributed to lipid sources in the media (blood serum supplement and plasma membranes of host cells). These lipid moieties could be utilized as signature markers for rapidly detecting the cell culture media. Viruses are intracellular parasites and are dependent upon host cells in order to exist. Therefore, it is highly probable that significant quantities of media needed to grow and maintain viable host cells would be present if a viral agent were disseminated as an aerosol into the environment. Cholesterol was also detected from a purified virus sample, further substantiating its use as a target compound for detection. Implications of this research for detection of viral bioaerosols, using a field-portable pyrolysis mass spectrometer, is described.  (+info)

Overlapping positive and negative GATA factor binding sites mediate inducible DAL7 gene expression in Saccharomyces cerevisiae. (4/150)

Allantoin pathway gene expression in Saccharomyces cerevisiae responds to two different environmental stimuli. The expression of these genes is induced in the presence of allantoin or its degradative metabolites and repressed when a good nitrogen source (e. g. asparagine or glutamine) is provided. Three types of cis-acting sites and trans-acting factors are required for allantoin pathway gene transcription as follows: (i) UAS(NTR) element associated with the transcriptional activators Gln3p and Gat1p, (ii) URS(GATA) element associated with the repressor Dal80p, and (iii) UIS(ALL) element associated with the Dal82 and Dal81 proteins required for inducer-dependent transcription. Most of the work leading to the above conclusions has employed inducer-independent allantoin pathway genes (e.g. DAL5 and DAL3). The purpose of this work is to extend our understanding of these elements and their roles to inducible allantoin pathway genes using the DAL7 (encoding malate synthase) as a model. We show that eight distinct cis-acting sites participate in the process as follows: a newly identified GC-rich element, two UAS(NTR), two UIS(ALL), and three URS(GATA) elements. The two GATA-containing UAS(NTR) elements are coincident with two of the three GATA sequences that make up the URS(GATA) elements. The remaining URS(GATA) GATA sequence, however, is not a UAS(NTR) element but appears to function only in repression. The data provide insights into how these cis- and trans-acting factors function together to accomplish the regulated expression of the DAL7 gene that is observed in vivo.  (+info)

Clostridium innocuum: a glucoseureide-splitting inhabitant of the human intestinal tract. (5/150)

Glycosylureides were recently described as non-invasive markers of intestinal transit time. The underlying principle is an enzymatic splitting of (13)C-labelled ureides by intestinal bacteria. The (13)CO(2) released from the urea moiety of the glycosylureides can be measured in breath samples when the ingested tracer substrate reaches the caecum that is colonised with microbes. To date, the microbes that degrade glycosylureides are unknown. In order to identify the glucoseureide (GU)-splitting bacteria, 174 different strains of intestinal microbes obtained from five healthy adults were checked for their ability to degrade GU. The results of the microbial cultures and thin layer chromatography revealed that GU was exclusively degraded by Clostridium innocuum, belonging to the normal human intestinal microflora. C. innocuum probably synthesises a yet unknown enzyme that splits the glucose-urea bond. We suggest that the term glucoseureidehydrolase is the appropriate designation for this enzyme.  (+info)

Genetic analysis of a chromosomal region containing genes required for assimilation of allantoin nitrogen and linked glyoxylate metabolism in Escherichia coli. (6/150)

Growth experiments with Escherichia coli have shown that this organism is able to use allantoin as a sole nitrogen source but not as a sole carbon source. Nitrogen assimilation from this compound was possible only under anaerobic conditions, in which all the enzyme activities involved in allantoin metabolism were detected. Of the nine genes encoding proteins required for allantoin degradation, only the one encoding glyoxylate carboligase (gcl), the first enzyme of the pathway leading to glycerate, had been identified and mapped at centisome 12 on the chromosome map. Phenotypic complementation of mutations in the other two genes of the glycerate pathway, encoding tartronic semialdehyde reductase (glxR) and glycerate kinase (glxK), allowed us to clone and map them closely linked to gcl. Complete sequencing of a 15.8-kb fragment encompassing these genes defined a regulon with 12 open reading frames (ORFs). Due to the high similarity of the products of two of these ORFs with yeast allantoinase and yeast allantoate amidohydrolase, a systematic analysis of the gene cluster was undertaken to identify genes involved in allantoin utilization. A BLASTP search predicted four of the genes that we sequenced to encode allantoinase (allB), allantoate amidohydrolase (allC), ureidoglycolate hydrolase (allA), and ureidoglycolate dehydrogenase (allD). The products of these genes were overexpressed and shown to have the predicted corresponding enzyme activities. Transcriptional fusions to lacZ permitted the identification of three functional promoters corresponding to three transcriptional units for the structural genes and another promoter for the regulatory gene allR. Deletion of this regulatory gene led to constitutive expression of the regulon, indicating a negatively acting function.  (+info)

Systematic review of comparative efficacy and tolerability of calcipotriol in treating chronic plaque psoriasis. (7/150)

OBJECTIVES: To evaluate the comparative efficacy and tolerability of topical calcipotriol in the treatment of mild to moderate chronic plaque psoriasis. DESIGN: Quantitative systematic review of randomised controlled trials. SUBJECTS: 6038 patients with plaque psoriasis reported in 37 trials. MAIN OUTCOME MEASURES: Mean difference in percentage change in scores on psoriasis area and severity index, and response rate ratios for both patients' and investigators' overall assessments of marked improvement or better. Adverse effects were estimated with the rate ratio, rate difference, and number needed to treat. RESULTS: Calcipotriol was at least as effective as potent topical corticosteroids, calcitriol, short contact dithranol, tacalcitol, coal tar, and combined coal tar 5%, allantoin 2%, and hydrocortisone 0.5%. Calcipotriol caused significantly more skin irritation than potent topical corticosteroids (number needed to treat to harm for irritation 10, 95% confidence interval 6 to 34). Calcipotriol monotherapy also caused more irritation than calcipotriol combined with a potent topical corticosteroid (6, 4 to 8). However, the number needed to treat for dithranol to produce lesional or perilesional irritation was 4 (3 to 5). On average, treating 23 patients with short contact dithranol led to one more patient dropping out of treatment owing to adverse effects than if they were treated with calcipotriol. CONCLUSIONS: Calcipotriol is an effective treatment for mild to moderate chronic plaque psoriasis, more so than calcitriol, tacalcitol, coal tar, and short contact dithranol. Only potent topical corticosteroids seem to have comparable efficacy at eight weeks. Although calcipotriol caused more skin irritation than topical corticosteroids this has to be balanced against the potential long term effects of corticosteroids. Skin irritation rarely led to withdrawal of calcipotriol treatment. Longer term comparative trials of calcipotriol versus dithranol and topical corticosteroids are needed to see whether these short term benefits are mirrored by long term outcomes such as duration of remission and improvement in quality of life.  (+info)

Ureide degradation pathways in intact soybean leaves. (8/150)

Ureides dramatically accumulate in shoots of N(2)-fixing soybean (Glycine max L. Merr.) under water deficit and this accumulation is higher in cultivars that have N(2) fixation that is sensitive to water deficit. One possible explanation is that ureide accumulation is associated with a feedback inhibition of nitrogenase activity. A critical factor involved in ureide accumulation is likely to be the rate of ureide degradation in the leaves. There exists, however, a controversy concerning the pathway of allantoic acid degradation in soybean. Allantoate amidinohydrolase was reported to be the pathway of degradation in studies using the cultivar Maple Arrow and allantoate amidohydrolase was the pathway that existed in the cultivar Williams. This investigation was undertaken to resolve the existence of these two pathways. An in situ technique was developed to examine the response of ureide degradation in leaf tissue to various treatments. In addition, the response of ureide accumulation and N(2) fixation activity was measured for intact plants in response to treatments that differentially influenced the two degradation pathways. The results from these studies confirmed that Maple Arrow and Williams degraded allantoic acid by different pathways as originally reported. The existence of two degradation pathways within the soybean germplasm opens the possibility of modifying ureide degradation to minimize the influence of soil water deficits on N(2) fixation activity.  (+info)

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