Tissue ascorbic acid and a liver dehydroascorbatase in guinea-pigs.

The extraction, partial purification and assay of a dehydroascorbatase from guinea-pig liver is described. There was no evidence that changes in dehydroascorbatase activity could account for the modified tissue ascorbic acid concentrations associated with aging or with the ingestion of fluoride, flavonoids or anthocyanin material.     

Fluorogenic amines in the notochords of chick embryos treated by cholinergics]

The investigation of 3 day old notochords by the fluorescence method of Falck and Owman showed an increase of the fluorescence after treatment of the chick embryos at 48 hrs of incubation, with nicotine sulfate or carbachol. The addition of norepinephrine or L-Dopa emphasized the formaldehyde induced fluorescence. The simultaneous treatment with a cholinergic agent and atropine, propranolol or reserpine decreased or suppressed the fluorescence. These results demonstrate the existence of a relationship between the treatment with a cholinergic agent and the amount of chordal biogenic amines.     

Granulocyte adhesion to nephritic glomeruli through recognition of activated C4 and C3 in immune deposits

Summary Sections of rat kidney with bovine serum albumin nephritis were incubated either with a single component of complement or with several components in sequence and then reacted with granulocytes. The average number of granulocytes bound to a nephritic glomerulus was elevated in sections incubated with C4 or C3 and increases were most significant when C14, C142 or C1423 were incubated.     

Granulocyte adhesion to nephritic glomeruli through recognition of activated C4 and C3 in immune deposits

Sections of rat kidney with bovine serum albumin nephritis were incubated either with a single component of complement or with several components in sequence and then reacted with granulocytes. The average number of granulocytes bound to a nephritic glomerulus was elevated in sections incubated with C4 or C3 and increases were most significant when C14, C142 or C1423 were incubated.     

L-arginine and pancreatic islet blood flow in anesthetized rats

The aim of the present study was to see if L-arginine, which induces insulin release and is a precursor of the endothelial-derived relaxing factor nitric oxide, affects whole pancreatic and/or islet blood flow. For this purpose, anesthetized male Sprague-Dawley rats were injected intravenously with either saline or L-arginine (25, 100 or 250 mg/kg body weight). All doses of arginine caused a slight increase in blood glucose concentration, while the highest dose (250 mg/kg body weight) also increased insulin concentration. However, no changes in either mean arterial blood pressure, whole pancreatic or islet blood flow could be discerned with any of the doses of arginine used. It is concluded that insulin release is not necessarily associated with an increased islet blood perfusion.     

Hsp70: a carrier molecule with built-in adjuvanticity

One problem associated with the development of subunit vaccines is their limited immunogenicity, due to their physico-chemical structure, their inability to encounter the correct MHC restriction element, or the need for strong adjuvants to be delivered along with them. These problems are usually solved by conjugating target epitopes (peptides or oligosaccharides) with carrier proteins which provide a source of T-cell epitopes recognised by a large proportion of the vaccinated individuals. We have shown that mycobacterial hsp65 and hsp70 exert a strong helper effect in vivo when conjugated to synthetic peptides or oligosaccharides. Interestingly, this helper effect did not require the need for any adjuvant, either in mice or in monkeys. The helper effect mediated by the hsp65 required that animals were previously primed with either live BCG or the hsp65 alone; on the other hand, such a priming was not required when the hsp70 was used in the conjugates. Similar results were obtained with HSP molecules fromEscherichia coli. This may suggest that the adjuvant-free helper effect observed applies not only to mycobacterial HSP, but also to HSP from other prokaryotes. These findings suggest that microbial hsp70 could be considered for the design of conjugated vaccine constructs for eventual human use.     

Inhibition of the reinitiation of meiosis in Xenopus laevis oocytes by three natural antiproteases: antipain, chymostatin, and leupeptin]

Oocytes incubated for 1 hr. in saline containing 1 mg/ml of antipain, leupeptin or chymostatin do not reinstate meiosis when progesterone or ionophore A 23187 are added. On the contrary such oocytes remain able to undergo meiosis when injected with cytoplasm of maturing oocytes (MPF), with Rabbit phosphorylase kinase or with Beef protein kinase. These results demonstrate that the loss of responsiveness to progesterone or ionophore is not due to toxic effects but rather to some interference with a key event which occurs prior to MPF action.     

Little effect of dimethyl sulfoxide on blood-brain barrier to dopamine

Summary Rats were treated with dimethyl sulfoxide (DMSO) intraperitoneally or intravenously, and simultaneously with dopamine (DA). The presence of DMSO resulted in small or no increases in brain levels of DA or its metabolites.Acknowledgments. Supported in part by the Parkinson's Disease Foundation and by a Peggy Engl Fellowship to Dr Walters.     

Purification of canine myocardial mitochondrial creatine kinase

Summary Mitochondrial creatine kinase, purified for the first time, is a dimeric molecule with a mol.wt of 82,000 and does not hybridize with M or B subunits or react to their specific antiserum. A specific antiserum to the mitochondrial form was developed which does not cross-react with the B or M subunits. Thus, the mitochondrial form is biochemically and immunologically unique.Supported in part by the Special Center of Research in Ischemic Heart Disease (1 P17 HL 17646).I thank Ann Grace for her technical assistance and Ava Ysaguirre for typing the mansucript.     

Odor maps in the brain: Spatial aspects of odor representation in sensory surface and olfactory bulb

The olfactory sense detects and distinguishes a multitude of different odors. Recent progress in molecular as well as physiological approaches has elucidated basic principles of neuronal encoding of odorants, common to insects and vertebrates. The construction of neuronal representations for odors begins with the task of mapping the multidimensional odor space onto the two-dimensional sensory surface, and subsequently onto the olfactory bulb or antennal lobe. A distributed expression of odorant receptors, albeit restricted to subregions of the sensory surface (large, intermediate or small for zebrafish, mouse or drosophila, respectively), ensures a robust representation, insensitive to mechanical insult. Olfactory receptor neurons expressing the same odorant receptors converge to form a receptotopic map in the olfactory bulb or antennal lobe. The emerging coding principle is a chemotopic representation of odorants at the first brain level, realized either as combinatorial or as monospecific representation, depending on the odorant.     

Analyse de l'induction neurale par autoradiographie

Summary Neural induction is accompanied by a migration of granules from the organizer to the reacting ectoblast (Brachet). The radioautographs of embryos or explants of amphibians seem to show that such a migration to the induced organs takes place when a marked organizer is grafted in a non-radioactive host.Substances of high molecular weight (proteins or nucleic acids) diffuse from an organizer tagged either with radioactive glycine or with radioactive orotic acid.     

Glycolipid transfer protein and intracellular traffic of glucosylceramide

Glycolipid transfer protein (GL-TP), a nonglycosylated protein with a molecular weight of 22,000 K, has been purified from pig brain. The protein transfers, by a carrier mechanism, glycolipids with a beta-glucosyl or beta-galactosyl residue directly linked to either ceramide or diacylglycerol. GL-TP appears to be present in most animal cells, and evidence has been obtained which indicates that it is a cytoplasmic protein. Little is known about the function of GL-TP. Current evidence indicates that glycosphingolipid glycosylation occurs at the luminal side of the Golgi apparatus, except for the glucosylation of ceramide, which has been shown to occur at the cytoplasmic side of the Golgi or endoplasmic membrane. It appears most likely that GL-TP participates in the intracellular traffic of glucosylceramide.     

Altered or increased transfer-RNA methylation in the course of Interferon action on cells in culture?

The induction of the antiviral state by Interferon might reflect the decrease of the rate of biosynthesis, the degradation or the alteration of one or several tRNAs. This could result in rate-limiting concentrations for codons common in viral RNA but rare in host mRNA. Altered methylation of tRNA could be the basis of such a phenomenon. However, we could not find an altered extent of methylation of total tRNA or an altered pattern of methylation, if mixed tRNAs were chromatographed on MAK- or BD-cellulose columns, despite a large range of conditions of pretreatment of chick embryo fibroblast cultures with interferon.     

Maturation of the female Tetrix undulata (Swrb) (Orthoptera, Tetrigidae): influence of the male and copulation:parthenogenetic egg-laying]

The percentage of laying females and laying time, are compared between mature females (diapause break by chilling) and diapause strain females (diapause not broken by chilling) reared with mature male or diapause male or without male. For the same physiological state of the females (mature or diapause) there is no difference in the percentage of females laying, when they are reared with mature male or with diapause one or none; but the laying time is shortest with mature male, longer with male in diapause, even longer without male. Parthenogenetic egg-pods can be obtain. Rearing with mature males does not break the reproductive diapause of females. In parthenogenetic egg-pods the number of eggs is short for low diapause females; greater for mature ones and greatest for females with strong diapause broken by a corpus allatum implant of mature female of Locusta migratoria. Corpus allatum of the low diapause strain of females of Tetrix undulata have less activity than that of mature females. Few parthenogenetic eggs develop, even less hatch. In Tetrix undulata parthenogenesis is accidental.     

Firewalking

Firewalking is known throughout recorded history and around the world. Ordinarily it is associated with religious beliefs or mystical states of mind in which the gods or unusual mental powers provide extraordinary protection for true believers or those with proper training. However, firewalking commonly involves hot materials of low heat capacity and poor thermal conductivity and sometimes the use of insulation. The excited or trance-like states of firewalkers contribute to the firewalkers' subjective experience but are not required for a successful walk. We conclude that elementary knowledge of physics and psychology is sufficient to explain the known observations of firewalking.     

Interaction of chlorpromazine with organic solvents and fatty acids as studied by UV-spectrophotometry

Summary The magnitude of the UV-spectral change of chlorpromazine increases in the presence of increasing concentrations of alcohols or fatty acids and with increasing chain length. A maximum is reached with 14.0- or 16.0-fatty acids. The difference spectrum is still larger with unsaturated fatty acids, a maximum effect being obtained with one cis-double bond. The spectral change is abolished by chaotropic and enhanced by antichaotropic agents.Supported by a grant of the Swiss National Science Foundation.     

Effect of some nitrotoluenes on the biotransformation of xenobiotics in rats

Summary Male rats were treated with phenobarbital, a dinitrotoluene (2,4-DNT or 2,6-DNT), or 2,4,6-trinitrotoluene (2,4,6-TNT); and the biotransformation of model xenobiotics was determined. Phenobarbital produced a stimulation, and 2,6-DNT produced a biphasic effect in biotransformation.     

Molecular mechanism for the production of multiple form of MM creatine kinase

Summary Incubation of human, canine or rabbit MM creatine kinase with carboxypeptidase-N or B resulted in the production of 2 additional enzyme forms with increased anodal migration on polyacrylamide gels. The C-terminal amino acid of tissue MM creatine kinase from all 3 species was shown to be lysine, a specific substrate for carboxypeptidase-N and B.     

Butterflies and ants: The communicative domain

Associations with ants, termed myrmecophily, are widespread in the butterfly family Lycaenidae and range from mere co-existence to more or less specific mutualistic or even parasitic interactions. Secretions of specialized epidermal glands are crucial for mediating the interactions. Transfer of nutrients (carbohydrates, amino acids) from butterfly larvae to ants plays a major role, but manipulative communication with the help of odour signals is also involved. By means of myrmecophily, lycaenid butterflies largely escape ant predation, and certain species gain protection through attendant ants or achieve developmental benefits from ant-attendance. Benefits to the ants range from minimal to substantial food rewards. While most lycaenid species maintain facultative relationships with a variety of ant genera, highly specific and obligatory associations have convergently evolved in a number of butterfly lineages. As a corollary, communication systems are largely unspecific in the former, but may be highly specialized in the latter. The sophisticated communication between obligate myrmecophiles and their host ants is tightly connected with the evolutionary rise of specialized life-cycles and thus is a source of augmenting diversity within the butterflies.