More than a leap of faith: the impact of biological and religious correlates on reproductive behavior

Using a conceptual model that integrates both social and biomedical factors of causation, this paper tries to delineate the pathways through which the reproductive characteristics of a multidenominational community are characterized. In total, 5513 historical entries from family reconstitution were available. Selection of data was guided by the inclusion of information about religious affiliation. Only married couples with children as well as single mothers with the relevant information were considered. Of these, 1855 entries were of Roman Catholic (C), 1143 of Lutheran/Protestant (L/P2), and 609 of Reformed Calvinist (R) denomination. The analysis documented differential nuptiality and fertility patterns, which at first glance may be interpreted along religious lines. However, the paper attempts to show that these various sociocultural patterns associated with religious behavior are merely proximate determinants, while the ultimate causes are biological in nature (i.e., differential parental age at marriage or birth, different parity progression regimes, differences in median interpregnancy interval, as well as highly variable sibship size within the denominational groups).     

Priapism: a review

Priapism is persistent penile erection in the absence of sexual stimulation. The pattern of blood flow to the penis that occurs during normal erection is altered so that sustained priapism may result in edema, increased risk of abrasion, tissue drying and necrosis of the penis. Numerous causes have been reported in animals and humans. The prognosis depends on the type of priapism and the amount of time that passes before therapeutic intervention. Surgical methods, such as aspiration and shunting procedures, have traditionally been used to treat priapism but carry a risk of postsurgical complications. Use of alpha-agonists for treatment of priapism in humans is often successful and avoids the risks of impotence and other surgical complications. Investigation of the use of alpha-agonists for treatment of priapism in animals should be considered.     

Edmund B. Wilson's the cell and cell theory between 1896 and 1925

Edmund Beecher Wilson is generally celebrated for his contribution to chromosome theory and genetics, whereas opinion concerning his cytological thinking is often restricted to the idea that he provided evidence for the dominant role of the nucleus. But Wilson's cell theory was much more. It was a child of the German Zellforschung, and its attempt to provide a comprehensive cellular answer to a wide range of biological and physiological questions. Wilson developed a corpuscular, micromeristic and preformistic concept, and treated the cell as an organism subject to ontogenetic and phylogenetic processes. He defended his comprehensive theory even in the 1920's, when cytological research had become specialised and directed at more practical goals. For many of his younger readers this concept might have seemed antiquated, but today many of its features sound surprisingly modern.     

Developmental roles of heparan sulfate proteoglycans: a comparative review in Drosophila,mouse and human

In recent years, progress in the fields of development and proteoglycan biology have produced converging evidence of the role of proteoglycans in morphogenesis. Numerous studies have demonstrated that proteoglycans are involved in several distinct morphogenetic pathways upon which they act at different levels. In particular, proteoglycans can determine the generation of morphogen gradients and be required for their signal transduction. The surface of most cells and the extracellular matrix are decorated by heparan sulfates which are the most common glycosaminoglycans, normally present as heparan sulfate proteoglycans. Considerable structural heterogeneity is generated in proteoglycans by the biosynthetic modification of their heparan sulfate chains as well as by the diverse nature of their different core proteins. This heterogeneity provides an impressive potential for protein-protein and protein-carbohydrate interactions, and can partly explain the diversity of proteoglycan involvement in different morphogenetic pathways. In this review, we summarize the current knowledge about mutations affecting heparan sulfate proteoglycans that influence the function of growth factor pathways essential for tissue assembly, differentiation and development. The comparison of data obtained in Drosophila, rodents and humans reveals that mutations affecting the proteoglycan core proteins or one of the biosynthetic enzymes of their heparan sulfate chains have profound effects on growth and morphogenesis. Further research will complete the picture, but current evidence shows that at the very least, heparan sulfate proteoglycans need to be counted as legitimate elements of morphogenetic pathways that have been maintained throughout evolution as determinant mechanisms of pattern formation.     

Maurotoxin versus Pi1/HsTx1 scorpion toxins. Toward new insights in the understanding of their distinct disulfide bridge patterns

Maurotoxin (MTX) is a scorpion toxin acting on several K(+) channel subtypes. It is a 34-residue peptide cross-linked by four disulfide bridges that are in an "uncommon" arrangement of the type C1-C5, C2-C6, C3-C4, and C7-C8 (versus C1-C5, C2-C6, C3-C7, and C4-C8 for Pi1 or HsTx1, two MTX-related scorpion toxins). We report here that a single mutation in MTX, in either position 15 or 33, resulted in a shift from the MTX toward the Pi1/HsTx1 disulfide bridge pattern. This shift is accompanied by structural and pharmacological changes of the peptide without altering the general alpha/beta scaffold of scorpion toxins.     

Chemical synthesis and characterization of maurocalcine, a scorpion toxin that activates Ca(2+) release channel/ryanodine receptors

Maurocalcine is a novel toxin isolated from the venom of the chactid scorpion Scorpio maurus palmatus. It is a 33-mer basic peptide cross-linked by three disulfide bridges, which shares 82% sequence identity with imperatoxin A, a scorpion toxin from the venom of Pandinus imperator. Maurocalcine is peculiar in terms of structural properties since it does not possess any consensus motif reported so far in other scorpion toxins. Due to its low concentration in venom (0.5% of the proteins), maurocalcine was chemically synthesized by means of an optimized solid-phase method, and purified after folding/oxidation by using both C18 reversed-phase and ion exchange high-pressure liquid chromatographies. The synthetic product (sMCa) was characterized. The half-cystine pairing pattern of sMCa was identified by enzyme-based cleavage and Edman sequencing. The pairings were Cys3-Cys17, Cys10-Cys21, and Cys16-Cys32. In vivo, the sMCa was lethal to mice following intracerebroventricular inoculation (LD(50), 20 microg/mouse). In vitro, electrophysiological experiments based on recordings of single channels incorporated into planar lipid bilayers showed that sMCa potently and reversibly modifies channel gating behavior of the type 1 ryanodine receptor by inducing prominent subconductance behavior.     

Very-Long-Chain Fatty Acids Are Involved in Polar Auxin Transport and Developmental Patterning in Arabidopsis

Very-long-chain fatty acids (VLCFAs) are essential for many aspects of plant development and necessary for the synthesis of seed storage triacylglycerols, epicuticular waxes, and sphingolipids. Identification of the acetyl-CoA carboxylase PASTICCINO3 and the 3-hydroxy acyl-CoA dehydratase PASTICCINO2 revealed that VLCFAs are important for cell proliferation and tissue patterning. Here, we show that the immunophilin PASTICCINO1 (PAS1) is also required for VLCFA synthesis. Impairment of PAS1 function results in reduction of VLCFA levels that particularly affects the composition of sphingolipids, known to be important for cell polarity in animals. Moreover, PAS1 associates with several enzymes of the VLCFA elongase complex in the endoplasmic reticulum. The pas1 mutants are deficient in lateral root formation and are characterized by an abnormal patterning of the embryo apex, which leads to defective cotyledon organogenesis. Our data indicate that in both tissues, defective organogenesis is associated with the mistargeting of the auxin efflux carrier PIN FORMED1 in specific cells, resulting in local alteration of polar auxin distribution. Furthermore, we show that exogenous VLCFAs rescue lateral root organogenesis and polar auxin distribution, indicating their direct involvement in these processes. Based on these data, we propose that PAS1 acts as a molecular scaffold for the fatty acid elongase complex in the endoplasmic reticulum and that the resulting VLCFAs are required for polar auxin transport and tissue patterning during plant development.