Application of matrix-assisted laser desorption ionization time-of-flight mass spectrometry with delayed ion extraction to ganglioside analyses

Various monosialo- and disialo-gangliosides and their derivativeswere examined by delayed ion extraction matrix-assisted laserdesorption ionization time-of-flight mass spectrometry (DE MALDI-TOFMS) in the reflector mode with     

H-2 restriction specificity of T cells from H-2 incompatible radiation bone marrow chimeras: Further evidence for the absence of crucial influence of the host/thymus environment on the generation of H-2 restricted TNP-specific T lymphocyte precursors

Experiments were conducted to answer the questions related to (a) the role played by the antigen-presenting cells (APCs) present within the thymus and (b) the effect of radiation dose to the recipients on the H-2 restriction profile of TNP-specific cytotoxic T lymphocyte precursors (CTLP) recovered from spleens and/or thymuses of H-2 incompatible radiation bone marrow chimeras (BMC). The H-2 restriction profile of intrathymically differentiating TNP-specific CTLPs was also analyzed in order to test an argument that donor-H-2 restricted CTLP detected in spleens of H-2 incompatible BMC were due to the extrathymically differentiated T cells under the influence of donor-derived lymphoreticular cells. The results indicated the following: (i) splenic T cells from B10(H-2^b)→ (B10(H-2^b) → B10.BR(H-2^k)) chimeras, which were constructed by irradiating primary BIO → B10.BR chimeras with 1100 R and reconstituting them with donor-type (B10) bone marrow cells as long as 8 months after their construction, manifested restriction specificities for both donor- and host-type H-2, (ii) splenic T cells from two types of (B10 × B10.BR)F₁→ B10 chimeras which were reconstituted after exposure of the recipients with either 900 or 1100 R with donor-type bone marrow cells generated both donor- and host-H-2 restricted TNP-specific cytotoxic T cells, and (iii) the TNP-specific CTLPs present in the regenerating thymuses of B10.BR → B10 and (B10 × B10.BR)F₁→ B10 chimeras 4 weeks after their construction were also shown to manifest both donor- and host-H-2 restriction specificities. The significance of these findings on the H-2 restriction profile of CTLP generated in BMCs is discussed.     

Steroids mediate resistance to the bactericidal effect of phosphatidylcholines against Helicobacter pylori

Helicobacter pylori assimilates various steroids as membrane lipid components, but it can also survive in the absence of steroids. It thus remains to be clarified as to why the organism relies on steroid physiologically. In this study, we have found that phosphatidylcholine carrying a linoleic acid molecule or arachidonic acid molecule has the potential to kill steroid-free H. pylori . The bactericidal action of phosphatidylcholines against H. pylori was due to the lytic activity of the phosphatidylcholines themselves and not due to the lytic activity of the unsaturated fatty acids or lyso-phosphatidylcholine resulting from the hydrolysis of the phosphatidylcholines. In contrast to the steroid-free H. pylori , the organism that absorbed and glucosylated free cholesterol was unaffected by the bactericidal action of the phosphatidylcholines. Similarly, H. pylori that absorbed estrone without glucosylating it also resisted the bactericidal action of the phosphatidylcholines. The steroids absorbed by H. pylori existed in both the outer and inner membranes, while the glucosyl-steroids produced via the steroid absorption were localized in the outer membrane rather than in the inner membrane. These results indicate that H. pylori absorbs the steroids to reinforce the membrane lipid barrier and thereby expresses resistance to the bacteriolytic action of hydrophobic compounds such as phosphatidylcholine.     

Rearing of a coleopterous predator,Trogossita japonica (Col.: Trogossitidae), on artificial diets

Artificial diets for a coleopterous predator of pine bark and wood borers,Trogossita japonica Reitter (Col.: Trogossitidae) were studied. Diets composed of silkworm pupa-powder, dry yeasts, sucrose, peptone, squid liver oil, agar and distilled water supported larval development. The size of diet-reared adults was smaller than that in the control but they mated and oviposited normally when maintained on prey insects. An aseptic rearing method for the larvae of predator, that required a single diet change, was devised.

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Résumé Nous avons élaboré et évalué quatre milieux semi-synthétiques pour l'élevage deTrogossita japonica Reitter, prédateur d'insectes sous-corticaux et xylophages des pins. Les larves ont été nourries avec des milieux composés de poudre de chrysalide du ver à soie, levure de bière séchée, sucrose, peptone, huile de foie de seiche, agar et eau distillée. Les adultes obtenus ont été plus petits que ceux du lot témoin, mais ils se sont accouplés et ont pondu normalement quand ils ont été nourris avec des proies-insectes. Une méthode d'élevage des larves sur milieu aseptique a été élaborée, laquelle ne nécessite qu'un changement de milieu nutritionnel au cours du développement larvaire du prédateur.

     

Yeast ribosomal proteins: V. Correlation of several nomenclatures and proposal of a standard nomenclature

Summary A tentative nomenclature (YP number) for yeast (Saccharomyces cerevisiae) cytoplasmic ribosomal proteins, which is used in our laboratory (Otaka and Kobata 1978; Higo and Otaka 1979), has been correlated with those of Warner and Gorenstein (1978) and several others. Our nomenclature is based on the two-dimensional gel electrophoretic pattern of proteins as analyzed by a modified method of Mets and Bogorad (1974), while others have used various modifications of Kaltschmidt and Wittmann's two-dimensional gel electrophoresis (1970). The method of correlation involved the examination in our twodimensional electrophoresis system of each protein spot excised from gel patterns prepared by Kaltschmidt and Wittmann's method or vice versa.The numbers of protein species recognized in this paper are 29 for small subunit, and 44 for large subunit. Based on these results, we propose a standard nomenclature for yeast ribosomal proteins, in which the designations YS1–YS29 and YL1–YL44 have been given to the small subunit proteins and the large subunit proteins respectively.     

Rapid diagnosis of cytomegalovirus infections by direct immunoperoxidase staining with human monoclonal antibody against an immediate-early antigen.

Direct immunoperoxidase technique using a horseradish peroxidase (HRP)-conjugated Fab' fragment of human monoclonal antibody (humab C7), designated HRP-C7, was evaluated as a rapid diagnosis of cytomegalovirus (CMV) infection. A total of 138 clinical specimens consisting of 124 urine samples and 14 oral swabs were examined for CMV by the direct HRP-C7 staining in comparison with conventional virus isolation. The number of CMV-positive samples by each method was 40 (29.0%) for the former and 37 (26.8%) for the latter, respectively. By HRP-C7 staining, CMV was identifiable within 24 hr after inoculation. By conventional isolation method, an average of 10.3 days had passed before cytopathic effect characteristic of CMV appeared in the cell culture. Some false-positive and false-negative cases were discussed in relation to toxicity of urine samples, storage of the samples, and amount of CMV in the sample. The sensitivity and specificity of HRP-C7 method against conventional isolation method were 89.2% and 93.1%, respectively. Thus, HRP-C7 staining is useful for a rapid diagnosis of CMV infections.     

Effect of Cocaine on the Histaminergic Neuron System in the Rat Brain

Abstract: To examine the effect of cocaine on the brain histamine neuron system, histamine levels and histamine N -methyl-transferase activity in the rat brain were measured after the administration of cocaine. Moreover, we examined the effect of l -histidine on cocaine-induced wheel-running behavior. The administration of cocaine (20 mg/kg) increased histamine levels and histamine N -methyltransferase activity in the striatum, nucleus accumbens, and amygdala 1 h later. The pretreatment with l -histidine (350 and 700 mg/kg) inhibited the cocaine (20 mg/kg)-induced increase of wheel-running activity in a dose-dependent manner. These findings suggest that cocaine activates the brain histamine neuron system, which may play the role of inhibiting the cocaine-induced wheel-running behavior.