Tangential cell migration during layer formation of chick optic tectum

The laminated structure of the optic tectum is formed by radial and tangential cell migration during development. Studies of developing chick optic tectum have revealed two streams of tangential cell migration in the middle and superficial layers, which have distinctive origins, migratory paths, modes of migration, and destinations. We will review the process of the two types of tangential migrations, in order to elucidate their roles in the formation of the optic tectum layers.     

Sequence of an operon containing a novel δ-endotoxin gene from Bacillus thuringiensis

An insect larval toxin designated CryII is produced by several subspecies of Bacillus thuringiensis and differs from the other major delta-endotoxins in these bacteria in its size, toxicity profile and presence as part of an operon with three open reading frames (ORF). Such an operon from a novel B. thuringiensis isolate has been cloned and differs from one previously characterized in the following ways: (a) the size and number of amino acid repeats in one of the ORFs; (b) the smaller size of the CryII protoxin and the presence of a unique 110-kDa CryII-related antigen; and (c) high larvicidal activity for a particular Lepidopteran but low activity for a Dipteran. Various subclones of this operon were introduced into a plasmid-free B. thuringiensis strain and only the cryII gene was found to be necessary for protoxin accumulation.     

N-Acetylsuccinimidylglutamate, a Cyclic Imide Form of the Peptide N-Acetylaspartylglutamate, Is Present in Low Micromolar Concentrations in Murine and Bovine CNS

Abstract: N -Acetylsuccinimidylglutamate [(asu)NAAG], a cyclic form of the peptide N -acetylaspartylglutamate (NAAG) in which the aspartyl residue is linked to glutamate via the α- and β-carboxylates, was identified and quantified by HPLC in the murine and bovine CNS. In the rat, the highest concentrations of (asu)NAAG were detected in the spinal cord (1.83 ± 0.15 pmol/mg of wet tissue weight) and brainstem (1.16 ± 0.08 pmol/mg wet weight), whereas the levels were below the limit of detection in cerebellum, hippocampus, and cerebral cortex. (Asu)NAAG was also detected in significant amounts in the superior colliculus and lateral genicutale nucleus (1.17 ± 0.05 and 0.82 ± 0.13 pmol/mg wet weight, respectively). Although the tissue content of (asu)NAAG was about three orders of magnitude lower than that of NAAG, levels of both peptides were positively correlated among different CNS regions ( r = 0.74, p < 0.003). In the rat spinal cord, (asu)NAAG levels progressively increased from week 2 to month 12 after birth. In bovine spinal cord, the contents of (asu)NAAG and NAAG were comparable in gray and white matter as well as in the dorsal and ventral horns. These results suggest that NAAG and (asu)-NAAG are closely related metabolically and raise the question of the physiological significance of such a cyclic peptide.     

A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Coprinopsis asiaticiphlyctidospora sp. nov., an agaric ammonia fungus from Amami and Okinawa,southern Japan

Coprinopsis asiaticiphlyctidospora (Basidiomycota, Psathyrellaceae), is a new Coprinoid ammonia fungus from Amami and Okinawa, Japan. In macro- and micro-morphology, this species is similar to C. phlyctidospora and C. austrophlyctidospora, but differs in having smaller basidiospores and spiny basidiospore ornamentation. Phylogenetic analysis with the nuclear ribosomal internal transcribed spacer (ITS) data also supports this new taxon.     

Granuloma formation to Capillaria hepatica eggs. I. Descriptive definition

The course of the cellular response in the liver to nonembryonated Capillaria hepatica (Bancroft, 1893) eggs given by intravenous injection into the portal circulation of unsensitized and sensitized mice was studied qualitatively and quantitatively. A gradual infiltration of predominantly mononuclear cells occurred around the eggs in the liver, leading to the formation of distinct granulomatous lesions characterized by macrophages and lymphocytes. This was followed by an infiltration of eosinophils. Previous intraperitoneal sensitization led to an earlier and an enhanced reaction to an intravenous challenge with eggs. Specificity of the cellular response was suggested by the lack of an enhanced reaction to presensitization with eggs of a closely related species, Trichuris muris. These studies indicate that granuloma formation to C. hepatica eggs has an immunological basis and furthermore the cell composition of the granuloma would suggest that a cell-mediated component may be involved as part of the specific response.     

Characterization of B and H blood-group active glycosphingolipids from human B erythrocyte membranes

Two blood group B active glycosphingolipids (B-I and B-II) previously isolated and highly purified from human B erythrocytes [21] were analysed first by degradation with α-D-galactosidase from coffee beans, α-L-fucosidase from bovine kidney and with 0,1 N trichloracetic acid; the native B-glycolipids as well as their degradation products were then investigated by methylation analysis with combined gas chromatography-mass spectrometry, by thin layer chromatography, twodimensional immunodiffusion and by the hemagglutination inhibition technique. Together with the results obtained by mass spectrometry of permethylated glycolipids [26] the following structures were elucidated: α-D-galactopyranosyl-(1 → 3)-[α-L-fucopyranosyl-(1 → 2)]-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-D-glucopyranosyl-(1 → 1)-ceramide for the B-I glycosphingolipid and α-D-galactopyranosyl-(1 → 3)-[α-L-fucopyranosyl-(1 → 2)]-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-D-glucopyranosyl-(1 → 1)-ceramide for the B-II glycosphingolipid. A H active glycolipid fraction from B erythrocytes further purified by thin layer chromatography was also investigated by methylation analysis. The pattern of its partially methylated alditol acetates was essentially the same as that of the α-galactosidase treated and permethylated B-I glycolipid. It also exhibited strongly precipitating and hemagglutination inhibiting H properties as well as the two α-galactosidase treated B-I and B-II glycosphingolipids. Based upon these data the following tentative structure was proposed: α-L-fucopyranosyl-(1 → 2)-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-D-glucopyranosyl-(1 → 1)-ceramide. Gas chromatographic analysis revealed sphingosine and lignoceric, nervonic and behenic acids to be the main components of the ceramide residues of the three glycosphingolipids. From the data presented the H active substance very probably can be regarded as the immediate precursor of the B-I glycosphingolipid from human B erythrocyte membranes.     

Effect of Temperature on the Formation of Microsclerotia of Verticillium dahliae

Microsclerotium formation by six isolates of Verticillium dahliae was studied at different temperatures both in vitro and in Arabidopsis thaliana . In vitro mycelial growth was optimal at 25°C, but microsclerotium formation was greatest at 20°C (two isolates) or 15–20°C (one isolate). Seedlings of A. thaliana were root-dipped in a conidial suspension, planted, and either placed at 5, 10, 15, or 25°C, or left at 20°C until the onset of senescence, after which some of the plants were placed at 5, 10, 15, or 25°C. The amount of microsclerotia per unit of shoot weight was assessed in relation to isolate and temperature. The optimal temperature for production of microsclerotia was 15–25°C. Two isolates each produced about 10 times more microsclerotia than each of the other four isolates. For these isolates, high R ²_adj.-values of 0.77 and 0.66 were obtained, with temperature and its square as highly significant (P   < 0.001) independent variables. R ²_adj.-values for the other isolates varied between 0.28 and 0.39. Moving plants to different temperatures at the onset of senescence led to microsclerotial densities that were intermediate between densities on plants that had grown at constantly 20°C and plants grown at other temperatures. This suggests that vascular colonization rate and rate of microsclerotium formation are similarly affected by temperature. The senescence rate of plants appeared unimportant except for plants grown at 25°C, which showed the highest amounts of microsclerotia per unit of plant weight in the most rapidly senescing plants.