Developmental regulation of presence of binding sites for neoglycoproteins and endogenous lectins in various embryonic stages of human lung,liver and heart

Protein-carbohydrate interactions are supposed to play key roles in the mechanisms of cell adhesion, biosignalling and intracellular routing, warranting the analysis of the developmental course of expression of epitopes of this system. Thus, a panel of carrier-immobilized carbohydrate ligands was used as probes, namely lactose,N-acetylgalactosamine,N-acetylglucosamine, mannose, fucose and maltose. Additionally, an antibody to an endogenous -galactoside-binding lectin (anti-galectin-1), the biotinylated lectin and two further human lectins, namely the macrophage migration inhibitory factor-binding sarcolectin and serum amyloid P component (SAP) that displays selectivity for sulphated sugars and mannose-6-phosphate, were included. They enabled us to assess the extent of the presence of respective binding sites in fixed sections from human lungs (pulmonary epithelial cells), livers (hepatocytes) and hearts (myocard cells) of 10–50 weeks gestation. Invariably, specific binding was detected in the three organ types, at least in certain stages. In most of the cases, the intensity of staining exhibited developmental regulation. The apparent patterns reveal similarities between the different cell types, as seen with immobilizedN-acetylglucosamine as well as with labelled galectin-1 and sarcolectin. However, drastic differences among such patterns with nearly opposite developmental courses do also occur, as detected for carrier-attached mannose and maltose residues. These results point to a potential importance for the detected glycohistochemical features in human development and substantiate the possibility of differential regulation of the presence of binding sites for distinct sugars within a certain organ and between the individual cell types of the monitored organs.     

Line x tester analysis for fixed effect model in cotton (Gossypium hirsutum L.)

Summary The data from an experiment in cotton consisting of three testers and 12 lines selected deliberately have been analysed. The investigation showed higher specific combining ability variance for yield of seed cotton and number of bolls, indicating the predominance of non-additive gene action. Of parental lines, H777 was found to possess high g.c.a. effects for seed cotton yield, number of bolls and number of sympodes. Parent H842 contributed only for boll weight, whereas H655 was good general combiner for number of monopodes. There appeared to be better chances for increasing the yield by exploiting hybrid vigour for the number of bolls and boll weight. The presence of marked non-additive gene effects, in addition to additive gene effects, indicated the need for exploiting both the fixable and non-fixable components of genetic variance for increasing productivity in cotton.     

Role of IAA conjugates in inducing ethylene production by tobacco leaf discs

Indole-3-acetic acid (IAA) labeled in its carboxyl group was metabolized by tobacco leaf discs (Nicotiana tabacum L. cv. Xanthi) into three metabolites, two of which were preliminarily characterized as a peptide and an ester-conjugated IAA. Reapplication of each of the three metabolites (at 10 M) resulted in a marked stimulation of ethylene production and decarboxylation by the leaf discs. Similarly, these three IAA metab olites could induce elongation of wheat coleoptile segments, which was accompanied by decarboxylation. Both the exogenously supplied esteric and peptidic IAA conjugates were converted by the leaf discs into the same metabolites as free IAA. (1-¹⁴C)IAA, applied to an isolated epidermis tissue, was completely metabolized to the esteric and peptidic IAA conjugates. This epidermis tissue showed much higher ethylene production rates and lower decarboxylation rates than did the whole leaf disc.The results suggest that the participation of IAA conjugates in the regulation of various physiological processes depends on the release of free IAA, which is obtained by enzymatic hydrolysis of the conjugates in the tissue. The present study demonstrates biological activity of endogenous IAA conjugates that were synthesized by tobacco leaf discs in response to exogenously supplied IAA.Contribution No. 952-E, 1983 series, from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel.     

A simple system for the Collection of Leaf-Derived Faecal Pellets of Aquatic Invertebrates

Animals and food (leaves) are confined at a desired temperature in a feeding chamber in the upper portion of the water column of a collector system. Egested material collects in water at 0°C also eliminates coprophagy and physical damage to the pellets.     

The characterization of the non-histone chromosomal proteins of the main classes of nuclei from rat brain fractionated by zonal centrifugation

1. Non-histone chromosomal proteins were isolated from the cell nuclei of whole rat brain and nuclei from different types of brain cells. 2. Brain nuclei were fractionated by zonal centrifugation into five zones deriving from five main categories of brain cells. These are the neuronals, astrocytes I, astrocytes II, oligodendrocytes I and oligodendrocytes II. 3. The non-histone chromosomal proteins were analysed by (a) sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, (b) electrofocusing electrophoresis and (c) two-dimensional electrophoresis. The results of this analysis showed a limited specific pattern of non-histone chromosomal proteins from the different classes of nuclei. Differences were found to exist between the proteins from neuronal and glial nuclei. In particular one polypeptide band with mol.wt. 10000 and pI8.5 was found to be present in the non-histone protein fractions of neuronal nuclei, and absent from the corresponding fractions of nearly all the other classes of nuclei. 4. Two other classes of nuclear proteins, buffered-saline-soluble and 0.35m-NaCl-soluble, were analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis along with the non-histone chromosomal. The similarities and differences among these groups of proteins are discussed. 5. The patterns of non-histone chromosomal proteins during development were investigated by studying them in two age groups of animals: in infant rats (10 days old) and adult rats. The polypeptide that was found to be specific for the proteins of neuronal nuclei of adult rats is present in all the classes of nuclei of infant rats.     

Distribution of 18+28S ribosomal genes in mammalian genomes

In situ hybridization with ³H 18S and 28S ribosomal RNA from Xenopus laevis has been used to study the distribution of DNA sequences coding for these RNAs (the nucleolus organizing regions) in the genomes of six mammals. Several patterns of distribution have been found: 1) A single major site (rat kangaroo, Seba's fruit bat), 2) Two major sites (Indian muntjac), 3) Multiple sites in centromeric heterochromatin (field vole), 4) Multiple sites in heterochromatic short arms (Peromyscus eremicus), 5) Multiple sites in telomeric regions (Chinese hamster). — The chromosomal sites which bind ³H 18S and 28S ribosomal RNA correspond closely to the sites of secondary constrictions where these are known. However, the correlation is not absolute. Some secondary constrictions do not appear to bind ³H ribosomal RNA. Some regions which bind ribosomal RNA do not appear as secondary constrictions in metaphase chromosomes. — Although the nucleolus organizing regions of most mammalian karyotypes are found on the autosomes, the X chromosomes in Carollia perspicillata and C. castanea carry large clusters of sequences complementary to ribosomal RNA. In situ hybridization shows that the Y chromosome in C. castanea also has a large nucleolus organizing region.     

Preliminary observations on nitrogen transport during summer in a small spring-fed Ontario stream

Nitrogen transport in a 2 km-long, spring-fed stream was studied during the summer months by analyzing weekly water samples from four stations. The water at the spring had a consistently high level of nitrate-N ranging from about 7 mg/l in late spring to about 3 mg/l in early fall. However, over the length of the stream, 60% (about 97 kg) of the incoming nitrate-N is lost from the water during the summer period. The loss, which does not appear to be attributable to the uptake by aquatic macrophytes or to immobilization, is thought to result from denitrification.     

Roles of Peroxisome Proliferator-Activated Receptor Gamma on Brain and Peripheral Inflammation

Peroxisome proliferator-activated receptor gamma (PPARγ) has been implicated in the pathology of numerous diseases involving diabetes, stroke, cancer, or obesity. It is expressed in diverse cell types, including vessels, immune and glial cells, and neurons. PPARγ plays crucial roles in the regulation of cellular differentiation, lipid metabolism, or glucose homeostasis. PPARγ ligands also exert effects on attenuating degenerative processes in the brain, as well as in peripheral systems, and it has been associated with the control of anti-inflammatory mechanisms, oxidative stress, neuronal death, neurogenesis, differentiation, and angiogenesis. This review will highlight key advances in the understanding of the PPARγ-related mechanisms responsible for neuroprotection after brain injuries, both ischemia and traumatic brain injury, and it will also cover the natural and synthetic agonist for PPARγ, angiotensin receptor blockers, and PPARγ antagonists, used in experimental and clinical research. A better understanding of the pleiotropic mechanisms and applications of these drugs to improve the recovery and to repair the acute and chronic induced neuroinflammation after brain injuries will pave the way for more effective therapeutic strategies after brain deficits.