Neuronal and Glial Marker Proteins in the Evaluation of the Protective Action of MK 801

A quantitative dot immunobinding procedure was used to quantify glial [the S-100 protein and the glial fibrillary acidic (GFA) protein] and neuronal (the 68- and 200-kDa neurofilament polypeptides, neuron-specific enolase, and neuronal cell adhesion molecule) markers. A single intraperitoneal administration of 10 mg/kg of MK 801 blocked the increase of glial parameters and the decrease in content of neuronal marker proteins that occurred as the response to an N-methyl-D-aspartate (NMDA) lesion in the rat hippocampus. The degradation products of GFA protein and the 68-kDa neurofilament polypeptide that were induced by the NMDA lesion did not appear after MK 801 treatment. This study shows that brain-specific proteins are a set of precise tools for the evaluation of neuroprotective effects of antagonists to excitatory amino acids.     

Notes on the genus Pteroceras (Orchidaceae)

A new name (Pteroceras semiteretifolium H. Æ. Peders.) and two new combinations (P. cladostachyum (Hook.f.) H. Æ. Peders., P. unguiculatum (Lindley) H. Æ. Peders.) are presented. The correct application of the name P. pallidum (Blume) Holttum is discussed.     

Evolution of structure and function of V-ATPases

Proton pumping ATPases/ATPsynthases are found in all groups of present-day organisms. The structure of V- and F-type ATPases/ATP synthases is very conserved throughout evolution. Sequence analysis shows that the V- and F-type ATPases evolved from the same enzyme already present in the last common ancestor of all known extant life forms. The catalytic and noncatalytic subunits found in the dissociable head groups of the V/F-type ATPases are paralogous subunits, i.e., these two types of subunits evolved from a common ancestral gene. The gene duplication giving rise to these two genes (i.e., encoding the catalytic and noncatalytic subunits) predates the time of the last common ancestor.Mapping of gene duplication events that occurred in the evolution of the proteolipid, the noncatalytic and the catalytic subunits, onto the tree of life leads to a prediction for the likely subunit structure of the encoded ATPases. A correlation between structure and function of V/F-ATPases has been established for present-day organisms. Implications resulting from this correlation for the bioenergetics operative in proto-eukaryotes and in the last common ancestor are presented. The similarities of the V/F-ATPase subunits to an ATPase-like protein that was implicated to play a role in flagellar assembly are evaluated.Different V-ATPase isoforms have been detected in some higher eukaryotes. These data are analyzed with respect to the possible function of the different isoforms (tissue specific, organelle specific) and with respect to the point in their evolution when these gene duplications giving rise to the isoforms had occurred, i.e., how far these isoforms are distributed.     

Inheritance of the group I rDNA intron in Tetrahymena pigmentosa

We have previously argued from phylogenetic sequence data that the group I intron in the rRNA genes of Tetrahymena was acquired by different Tetrahymena species at different times during evolution. We have now approached the question of intron mobility experimentally by crossing intron⁺ and intron^? strains looking for a strong polarity in the inheritance of the intron (intron homing). Based on the genetic analysis we find that the intron in T. pigmentosa is inherited as a neutral character and that intron⁺ and intron^? alleles segregate in a Mendelian fashion with no sign of intron homing. In an analysis of vegetatively growing cells containing intron⁺ and intron^? rDNA, initially in the same macronucleus, we similarly find no evidence of intron homing. During the course of this work, we observed to our surprise that progeny clones from some crosses contained three types of rDNA. One possible explanation is that T. pigmentosa has two rdn loci in contrast to the single locus found in T. thermophila. Some of the progeny clones from the genetic analysis were expanded for several hundred generations, and allelic assortment of the rDNA was demonstrated by subcloning analysis. © 1992 Wiley-Liss, Inc.     

A naturally occurring mutation of insulin receptor alanine 1134 impairs tyrosine kinase function and is associated with dominantly inherited insulin resistance

We have identified a previously undescribed genetic variant of the insulin receptor (Ala1134----Thr1134) in a family with the Type A syndrome of insulin resistance. Using the polymerase chain reaction to amplify insulin receptor cDNA and genomic DNA (exon 19), this mutation was detected in 1/2 alleles in the proband, her two affected sisters, and her affected father. Two normal alleles were present in the unaffected mother. No additional structural changes were encoded by the remainder of the proband's receptor cDNA. The Ala1134 mutant receptor was expressed in Chinese hamster ovary cells. The expressed mutant receptors were processed normally and displayed normal affinity of insulin binding but were markedly deficient in insulin-stimulated autophosphorylation. The mutant receptor was unable to catalyze the phosphorylation of the endogenous substrate, pp185, and insulin-stimulated kinase activity toward an exogenous substrate in vitro also was markedly impaired. Ala1134 is a highly conserved residue located in a consensus sequence found in most tyrosine kinases. It is likely that this previously uncharacterized residue and/or the immediate region surrounding it are important for normal kinase function in other members of this receptor family. This study also demonstrates that severe insulin resistance with dominant inheritance may be caused by a missense mutation in one allele of the insulin receptor gene.     

The Optomotor Response in Weak-electric Mormyrid Fish: Can they See?

The present study has explored the optomotor response in two species of mormyrid fish, Gnathonemus petersii and Brienomyrus niger. Both species tended to follow a black and white striped stimulus pattern under illumination levels of 6, 12, and 60 lx. The optomotor response ceased to occur under 540 lx. The behavioral data support earlier histological findings implicating the mormyrid retina in dim light vision.     

A quantitative and qualitative study of blood monocytes in patients with bronchogenic carcinoma

Summary Absolute circulating number and functions of blood monocytes (i.e., pinocytosis, phagocytosis, and chemotaxis) were studied in 25 patients with untreated bronchogenic carcinoma and in 28 control subjects. The absolute circulating monocyte count was increased in 20 (80%) of the patients. There was no difference in the pinocytic and phagocytic activity of patient and control monocytes. In contrast, patient monocytes showed depressed chemotactic responsiveness. This defect was more severe in small cell anaplastic carcinoma than in the other histologic types of bronchogenic carcinoma (P=0.001), and may explain the difference in macrophage infiltration seen in solid tumours of the lung. There was no correlation between chemotaxis and clinical stage. Depressed chemotaxis may be related to a plasma factor, since patient plasma inhibited the chemotaxis of control monocytes as well as the activity of chemotactic agents. The defective chemotaxis and the presence of plasma inhibitory activity may interfere with the ability of blood monocytes to accumulate as macrophages in tumour sites. Abbreviations used in this paper are: MCR, monocyte chemotactic response; SAC, small cell anaplastic bronchogenic carcinoma; OBC, non-small cell bronchogenic carcinoma MEM, Eagle's minimal essential medium; CFI, chemotactic factor inhibitor(s); HSA, human serum albumin     

The distribution of cationized ferritin receptors on ciliated epithelial cells of rat trachea

The interaction of tracheal cilia with the biphasic mucus layer covering the surface of the mammalian respiratory tract may be influenced by many cell surface coat components including those having an overall negative charge. In order to assess the distribution of ciliary anionic sites, cationized ferritin (CF) was used to label the surface of rat tracheal epithelium. If pieces of trachea were fixed with 3% glutaraldehyde and treated with CF at low (L) (0.08 mg/ml), medium (M) (0.32 mg/ml PBS), or high (H) (0.64 mg/ml PBS) concentrations, the label was distributed evenly over the entire external surface of the ciliary membrane at all concentrations. Unfixed tracheal tissue was also treated with L, M, and H CF for 1 or 5 min at 4 degrees C in order to minimize lateral redistribution of CF receptors. To ensure accessibility of the cell surface to CF the samples were agitated thoroughly during exposure. Exposure for 1 min to L, M, and H CF resulted in a light binding of ferritin particles on all portions of the ciliary membrane with occasional areas of multilayered binding distributed randomly on the ciliary shaft. When unfixed trachea was treated with CF for 5 min at 4 degrees C, CF binding was similar except heavier and more uniform. In no instance was there any preferential binding of CF to the ciliary tips at any of the concentrations used. Moreover, as indicated by the CF binding pattern at L concentrations, high density negative charges are present over almost the entire surface of the cilium. These results suggest that, unlike the ciliary membrane of other organs such as oviduct, negatively charged cell surface coat molecules are present on all areas of the ciliary membrane of rat tracheal epithelia.     

On the distribution of Rostkovia magellanica (Juncaceae), a species newly rediscovered in Ecuador

Rostkovia magellanica has hitherto been considered a species of Patagonia and the subantarctic islands from New Zealand to South Georgia. An old report from Ecuador has been considered erroneous, but it has now been rediscovered there. Brief notes on the ecology of the species are given, and the possible origin of its distribution is discussed. Long-distance dispersal by birds is suggested as having caused the disjunct distribution on mainland South America.