Hydrocephalus in suckling rats infected intracerebrally with mouse hepatitis virus, MHV-A59

After intracerebral inoculation of mouse hepatitis virus, MHV-A59 strain, into 3- to 5-day-old Wistar rats, some survivors at 14 days postinoculation (p.i.) were found to lack the cerebral cortex and to have an accumulation of considerable amount of cerebrospinal fluid. The virus titer in the brain increased exponentially after inoculation, reaching a maximum 4 to 6 days p.i. when immunofluorescence revealed virus-specific antigen within neurons in the cerebral cortex. A small amount of infectious virus was also detectable 14 days p.i. when the cerebral anomaly was evident. This brain malformation causing hydrocephalus was due to cerebral damage by viral infection.     

N-(Carboxyacyl)chitosans

Hemicelluloses were isolated from pineapple-leaf fibers under different conditions. Study of the properties of these hemicelluloses gave direct evidence of some ester linkages between the hemicellulose and the lignin in this fiber. An aldobiouronic acid was isolated from this fiber hemicellulose, and characterized as 2-O-(4-O-methyl-α-d-glucopyranosyluronic acid)-d-xylose. This indicates that the general nature of the hemicellulose is similar to those of jute and other fiber hemicelluloses.     

Effect of fatty acids and monoglycerides on permeability of lipid bilayer

The effect of fatty acids and monoglycerides on barrier properties of liposomal membranes prepared from egg phosphatidylcholine was investigated. The incorporation of these lipids as liposomal membrane components induced the alteration of the permeability to less permeable liposomally entrapped drugs, sulfanilic acid and procainamide ethobromide (PAEB). Monoolein caused greatly increased permeability of both drugs and unsaturated fatty acids markedly enhanced the release rate of PAEB, while saturated fatty acids caused a small increase in the release rate.Electron spin resonance (ESR) investigation with 5-nitroxide stearic acid showed that fatty acids disordered the hydrophobic region of the lipid bilayer and the disordering effect of unsaturated fatty acids was greater than that of saturated ones. It was demonstrated that the incorporated fatty acids and monoglycerides interacted with the polar region of the membranes by ESR study with cholestane label and ¹H-NMR study. These results indicated that the increase in the membrane permeability caused by fatty acids and monoglycerides associated with the disorder in the membranes' interior and the interaction of the incorporated lipid with the polar head group of phospholipid.     

Nitrate and nitrite in interstitial waters of eelgrass beds in relation to the rhizosphere

The distribution of nitrate and nitrite in the interstitial water of the sediment of eelgrass (Zostera marina) bed of Izembek Lagoon, Alaska, were investigated. Their concentrations were relatively high (0 to 9.8 μg-at.N·1^?1, average 4.8 for nitrate; 0 to 4.0 μ-at.N·1^?1, average 1.9 for nitrite) although the sediments were anoxic and contained hydrogen sulphide. The rates of bacterial denitrification measured by ¹⁵N tracer technique ranged from 0.49×10^?10 to 1.2 × 10^?9 g-atN·g^?1·h^?1. When a steady state is maintained, the loss of nitrate and nitrite must be balanced by their production by bacterial nitrification. Experimentally determined rate of nitrification in the sediment was of the same order. A model experiment demonstrated that oxygen is transported from leaves to rhizomes and roots of eelgrass and released into the sediment. The oxygen is used for nitrification in the rhizosphere in anoxic sediments.     

Mineral nutrition of cultured chlorophyllous cells of tobacco IV. Kinetic studies of K and Mg uptake by the cells

1. When applying the adsorption theory to the selectivity coefficient,K and Mg uptakes by cells in a K-Mg replacement series of mediaare not regulated only by a common mechanism, under the assumptionthat b values, which indicate the affinities between the ionand the adsorptive surface, do not change.
2. Regulation of Kand Mg uptakes by a common multiphasic mechanismin the cellsis possible when the selectivity coefficient b_K/b_Mgvaries inverselywith the M_K/M_Mg ratio in the external medium.
3. K and Mg uptakesare not regulated only by their respectivesingle specific mechanisms.
4. Another possibility is regulation of K and Mg uptakes bothbycommon and specific mechanisms. The common mechanism maybemultiphasic.

(Received December 2, 1975; )     

N-acetylchitosan gel: A polyhydrate of chitin

N-Acetylchitosan gel, a polyhydrate of chitin, and partially O-acetylated N-acetylchitosan gel were produced by a facile acetylation of chitosan with acetic anhydride in 10% acetic acid and in aqueous acetic acid/methanol at room temperature. Under the same conditions, a series of N-acylchitosan gels was produced in reaction with the other carboxylic anhydrides. The gels thus produced were colorless, transparent and rigid, and stable on heating. The gels were insoluble in cold and boiling water, formic acid, aqueous acids, and the other solvents examined. Significant changes in specific rotation occurred in the acylation of chitosan and its aggregation.     

A Nosema species of the Egyptian cotton leafworm, Spodoptera litura (Lepidoptera): Its morphology,development, host range,and taxonomy

A microsporidian was isolated from the Egyptian cotton leafworm, Spodoptera litura, and was identified as a member of the genus Nosema since its sporont produced two spores. The size of the fresh spores was 3.3–4.5 × 1.7 – 2.2 μm. Mean length of the polar filaments was 90.7 μm. In addition to the Egyptian cotton leafworm, this microsporidian was also infectious to Pieris rapae crucivora, Hyphantria cunea, Chilo suppressalis, Agrotis ipsilon, and Adoxophyes orana. Although the parasite ultimately caused generalized infection in the Egyptian cotton leafworm larva, the main site of infection was the adipose tissue.     

Distribution of ferritin-conjugated lectins on sialidase-treated membranes of human erythrocytes

The labeling of sialidase-treated, human erythrocyte membranes with ferritin-conjugates of four plant lectinss, concanavalin A, Ricinus communis hemagglutinin, Bauhinia purpurea hemagglutinin and Arachis hypogoea hemagglutinin, is reported. Among these ferritin-conjugated lectins, ferritin-conjugated concanavalin A and ferritin-conjugated R. communis hemagglutinin were found in clusters on the sialidase-treated membranes, whereas ferritin-conjugated B. pupurea hemagglutinin and ferritin-conjugated A. hypogoea hemagglutinin were found in a random distribution on the membranes. Furthermore, when the membranes were labeled with a mixture of concanavalin A and ferritin-conjugated B. purpurea hemagglutinin, ferritin particles were found in clusters, indicating that the membrane receptors for B. purpurea hemagglutinin were forced to move together with those for concanavalin A. A method for thentitative estimation of the clustering of ferritin particles on the membranes was also devised and applied to the labeling of sialidase-treated, human erythrocyte membranes with the above four ferritin-conjugated lectins.     

l-2-Amino-4-methylpimelic acid: A new amino acid from Lactarius species

A PC survey revealed the occurrence of an unusual amino acid in fruit bodies of the mushroom Lactarius quietus Fr. and a related species. This was identified as l-2-amino-4-methylpimelic acid, which has not been previously reported as a naturally occurring compound.     

Repression of porin synthesis by salicylate in Escherichia coli, Klebsiella pneumoniae and Serratia marcescens

The synthesis of the OmpF porin in Escherichia coli K-12 was highly and reversibly inhibited by 5 mM salicylate in the bacterial growth medium, and salicylate also inhibited the OmpC porin synthesis, although only weakly. The full expression of the salicylate effect was presumed to require the ompB gene product on comparison between the wild type and ompB mutant strains. The salicylate effect was also observed for the porin protein synthesis in Klebsiella pneumoniae and Serratia marcescens, although an ompB-like gene remains to be identified in both species.