Factors affecting the glycosphingolipid composition of murine tissues

The effects of genetic strain, sex, age, and pathological state on the distribution and concentration of glycosphingolipids in mouse kidneys and livers were studied. The concentrations of glycosphingolipids and phospholipids in the kidneys and livers of different strains were compared. The major glycosphingolipid in the kidneys of male and female BALB/c, C3H/He, C57/BL, A, and C57xA (F(1) hybrid) mice was a sulfatide, monoglycosyl-(3-sulfate) ceramide; monoglycosyl ceramide was the major component in livers. The kidneys of males of all strains contained significant amounts of diglycosyl ceramide, but those of females contained, at most, only traces. Glycosphingolipid concentration in the male kidneys of C57/BL and C57xA (F(1) hybrid) was much higher than in the female and was also much higher than in the male kidneys of C3H/He, BALB/c, and A strains. The kidneys of "old" (36 wk) male and female C3H/He mice contained much higher proportions of monoglycosyl ceramide than 10-12-wk-old adults. The distributions of glycosphingolipids in kidneys of female C3H/He mice with BP8 ascites tumors and male C57xA (F(1) hybrid) mice with EL4 ascites tumors differed from those in the normal mice. An unknown lipid, present in all glycosphingolipid extracts from kidney and liver, was tentatively identified as cholesterol sulfate.     

The oxidation products of crude mesobilirubinogen

Bile pigment esters were separated by ascending t.l.c. Apparently pure pigments, obtained by ferric chloride oxidation of crude mesobilirubinogen, derived from commercial bilirubin by reduction with sodium amalgam, were shown to be complex mixtures. Successive chromatography of their dimethyl esters on silica gel in methyl acetate-methyl propionate-dichloromethane-carbon tetrachloride (1:1:1:1, by vol.), ethyl methyl ketone-1,2-dichloroethane (1:2, v/v) and benzene-ethanol (100:3, v/v) revealed two major blue pigments (verdins), six major violet pigments (violins) and a red pigment (rhodin) together with numerous minor components. i-Urobilin dimethyl ester, prepared from mesobilirubinogen by dehydrogenation with aqueous iodine, was resolved into three major and at least four minor components on silica gel-kieselguhr (3:1, w/w) in benzene-ethanol (25:2, v/v). The chemical nature of these pigments was investigated by oxidation, by visible and u.v. spectroscopy, by mass spectrometry and by n.m.r. spectrometry. The evidence suggests unusual rearrangement of bilirubin during reduction leading to the formation of IIIalpha and XIIIalpha isomers. Isomeric forms of mesobiliviolin IXalpha and of i-urobilin IXalpha may also be formed.     

Characteristics of PRD1, a Plasmid-Dependent Broad Host Range DNA Bacteriophage

Several distinctive properties of PRD1, an icosahedral plasmid-dependent phage, are described. The drug-resistance plasmid-dependent host range of PRD1 extends beyond the P incompatibility group and includes gram-negative bacteria containing plasmids of incompatibility groups N and W. PRD1 phage will infect pseudomonads and Enterobacteriaceae containing either a P or W incompatibility group plasmid. PRD1 adsorbs to the cell wall of R(+) bacteria and thus its infectivity indicates cell wall alterations by these drug-resistance plasmid groups. PRD1 nucleic acid is duplex DNA with an estimated molecular weight of 24 x 10(6). The appearance of PRD1 in electron micrographs is suggestive of lipid content in addition to its buoyant density of 1.348 in CsCl and its sensitivity to chloroform. The latent period of PRD1 varies with the R(+) host bacterial strain used for growth of the phage.     

Circular dichroism spectra of poly[d(AC):d(GT)], poly[r(AC):r(GU)], and hybrids poly[d(AC):r(GU)] and poly[r(AC):d(GT)] in the presence of ethanol.

Ultraviolet circular dichroism spectra have been obtained in aqueous solutions in the presence and absence of ethanol for a synthetic DNA, poly[d(AC):d(GT)], a synthetic RNA, poly[r(AC):r(GU)], and two DNA:RNA hybrids, poly[d(AC):r(GU)] and poly[r(AC):d(GT)]. In the absence of ethanol, we find that the RNA and DNA spectra are dissimilar, while the spectra of the hybrids show differing degrees of similarity to that of the RNA. In the presence of 60–80% ethanol by weight, the spectra of the DNA and both hybrids become much closer to the spectrum of the RNA, which remains relatively unchanged. We interpret the results as indicating that DNA can undergo a change to an A-type conformation in the presence of ethanol and that the DNA:RNA hybrids are not wholly restricted to an RNA-like conformation in the absence of ethanol.     

Growth characteristics of two HeLa S3 strains possessing low level glucocorticoid-inducible and high level suppressible alkaline phosphatase.

Sperm of the sea urchin, Anthocidaris crassispina loses its fertilizing capacity, without losing its motility, on prior exposure to both native and trypsin-digested, univalent Concanavalin A (Con A). Neither agglutination nor acrosome reaction is evoked by ConA treatment. Fluorescein-conjugated ConA binds to the apex of sperm head and to the midpiece. The observed effects of ConA are cancelled by methyl α-d-mannoside. ConA neither binds to sperm of Hemicentrotus pulcherrimus nor renders it infertile. Fertilizability of egg of both species is not reduced by ConA, though formation of the fertilization membrane and 1st cleavage are seriously affected. It is suggested that the species-specific polysaccharide component is situated on the apex of the sea urchin sperm head and constitutes the counterpart to the sperm-binding protein of the vitelline membrane of the egg which belongs to the same species.     

Notes on the biology of the ant speciesMyrmecia dispar (Clark) (Hymenoptera: Formicidæ)

Myrmecia dispar (Clark) is found in the drier inland areas of New South Wales and southern Queensland in Australia. Its nests, which are situated adjacent to trees, have a distinctive structure of simple architecture. The composition of the colonies varies seasonally with little or no brood production during the colder months. Colony founding probably takes place in March, April, and/or May. Several myrmecophiles are found in nests ofM. dispar, and some of these are present in relatively large numbers.     

The use of fluorescein diacetate and ethidium bromide as a viability stain for isolated islets of Langerhans

There is a need for a simple, rapid, sensitive method for assessing the viability of isolated islets of Langerhans. In this study the fluorescent dyes fluorescein diacetate (FDA) and ethidium bromide (EB) have been used to provide a viability assay for isolated rat islets. Discrimination of living from dead islets is efficient; in a blind sorting experiment using freshly isolated islets and islets killed by either heat or alcohol, viability determined by insulin secretion in response to glucose stimulation correlated well with viability as determined by FDA/EB staining. Furthermore, it is possible to discriminate degrees of viability, and a scoring system is described for this purpose which is shown to correlate with another index of viability, the ATP content. A reliable viability stain should not itself be toxic; FDA/EB stained islets remain viable after staining, showing normal response to glucose stimulation and normal function after transplantation.