Oviduct histochemistry and site of synthesis of a 29.7 kDa jelly coat glycoprotein in the anuran Lepidobatrachus laevis

The oviduct of the anuran Lepidobatrachus laevis contains three morphological regions, each of which contains a histochemically distinct luminal mucosa. In the pars recta, the most anterior portion of the oviduct, there are periodic acid-Schiff base (PAS)-positive simple glands and epithelia. In the pars convoluta, there are alcian blue-positive, combined alcian blue- and PAS-positive and PAS-positive gland types. The most posterior region, the pars uterina, contains alcian blue-positive and alcian blue-negative epithelial cells. Previous work has shown that solubilized egg jelly contains a major 29.7 kDa glycoprotein subunit that was detected in oviduct tissue extracts from the pars convoluta in the present study. Rabbit antisera to the 29.7 kDa egg jelly glycoprotein of L. laevis reacted with the major pars convoluta glycoprotein and there were no immunoreactive components in the pars uterina. The slight immunoreactivity detected at 29.0–37.0 kDa in pars recta extracts is not believed to be the jelly molecule, based on low immunoreactivity and subunit molecular weight measurements. We conclude that the synthesis of the 29.7 kDa egg jelly glycoprotein is restricted to the pars convoluta region of the oviduct.     

Roseadione,a diterpene ketone from Hypoestes rosea

A tricyclic diterpene ketone, roseadione, has been isolated from Hypoestes rosea and its structure established as a dicyclopenta[a, d]cyclo     

Glycoproteins of trypanosomes: their biosynthesis and biological significance

1. Trypanosomes are unicellular parasites that cause human sleeping sickness in Africa and Chagas' disease in South America. Glycoproteins are important components of their plasma membrane. 2. The bloodstream form of the extracellular salivarian African trypanosome (e.g. Trypanosoma brucei) has the ability to express on its cell surface a repertoire of variant surface glycoproteins (VSGs) and in so doing, evades the immune response of the host (antigenic variation). 3. The VSG is probably synthesized initially in a manner like that of the membrane-bound glycoproteins of mammalian systems, but it also undergoes some novel post-translational modifications. 4. The stercorarian South American trypanosome (Trypanosoma cruzi) is an intracellular parasite which expresses different glycoproteins on its plasma membrane at various stages of its life-cycle, but does not exhibit antigenic variation. 5. The biosynthesis and functions of trypanosomal glycoproteins are compared with those of mammalian glycoproteins, and are discussed with particular reference to potential targets for chemotherapy and immunotherapy of trypanosomiasis.     

Print news coverage of cancer: What prevention messages are conveyed when screening is newsworthy?

Background: Americans are generally favorable towards cancer screening, but fatalistic about cancer prevention. News coverage shapes perceptions of cancer control in meaningful ways, but there is little consensus as to the impact of news on our understanding of and engagement in cancer screening practices. Our analysis of cancer screening-related print news coverage during a four month period in 2005 suggests that the newsworthiness of new screening technologies may undermine public confidence in currently available and effective secondary prevention programs, while promoting tests whose effectiveness is debated or not yet established. Methods and results: We conducted a structured text analysis of 517 cancer-related news articles from 15 leading daily newspapers and a subsequent qualitative analysis of the 79 screening news articles. Screening articles were analyzed for content related to criteria for screening effectiveness. Content patterns for each type of screening and cancer were also noted. News coverage consistently conveyed screening as important and highlighted the need to protect and expand access to screening. At the same time, to the extent that story content was framed by the newsworthiness of new tests and technologies this often indirectly called into question effective and established protocols and programs without providing any actionable alternative. Conclusion: This analysis revealed unexpected messages about screening that are potentially problematic for cancer control. The cancer control community should continue efforts to understand and shape news coverage of screening in order to promote balanced and action-oriented content. Research has shown that Americans hold conflicting views regarding cancer—having a favorable opinion of screening while simultaneously feeling fatalistic about prevention. Our analysis of print news stories on cancer screening suggests that the determination of screening's “newsworthiness” is related to newly developed tests and protocols, which may create demand for new tests whose effectiveness is unknown and undermine confidence in established and effective screening programs.     

A lysophosphatidic acid-binding cytosolic protein stimulates mitochondrial glycerophosphate acyltransferase

Rat liver cytosolic fraction caused up to five fold stimulation of mitochondrial glycerophosphate acyltransferase apparently by removing the lysophosphatidic acid formed by the acyltransferase. When mitochondria were incubated with palmityl-CoA, [2-3H]-sn-glycerol 3-phosphate and the cytosolic fraction and the supernatant fluid of the incubated mixture was passed through a Sephadex G-100 column, labeled lysophosphatidic acid eluted in three peaks with Mrs (i) 60-70 kDa, (ii) 10-20 kDa, and (iii) less than 5 kDa. Proteins, responsible for binding of lysophosphatidic acid in peaks (i) and (ii), were purified to near homogeneity as judged by electrophoretic analysis. The lysophosphatidic acid binding protein in peak (i) appears to be serum albumin and peak (iii) represents largely unbound lysophosphatidic acid. The 15 kDa protein, purified from peak (ii), bound lysophosphatidic acid, stimulated the acyltransferase and export of lysophosphatidic acid from mitochondria.     

Down-regulation of miR-17 family expression in response to retinoic acid induced neuronal differentiation

Whole-genome microRNA and gene expression analyses were used to monitor changes during retinoic acid induced differentiation of neuroblasts in vitro. Interestingly, the entire miR-17 family was over-represented among the down-regulated miRNA. The implications of these changes are considerable, as target gene prediction suggests that the miR-17 family is involved in the regulation of the mitogen-activated protein kinase (MAPK) signaling pathway, synaptic plasticity and other markers of neuronal differentiation. Significantly, many of the target responses predicted by changes in miRNA expression were supported by the observed changes in gene expression. As expected, markers of neuronal differentiation such as anti-apoptotic protein B-cell lymphoma 2 (BCL2), myocyte enhancer factor-2D (MEF2D) and zipper protein kinase (MAP3K12; aka ZPK/MUK/DLK) were each up-regulated in response to differentiation. The expression of these genes was also reduced in response to miR-17 and miR-20a transfection, and more specifically they were also shown to contain functional miRNA recognition elements for members of the miR-17 family by reporter gene assay. This suggests that the miR-17 family have an integral role in fine-tuning the pathways involved in the regulation of neuronal differentiation.