Regulation of energy economy in raccoon dogs and blue foxes: a process of dynamic interactions

1. Seasonal regulation of energy economy was studied in farm-raised blue foxes (Alopex lagopus) and raccoon dogs (Nyctereutes procyonoides; Gray, 1834). 2. Both species exhibited marked seasonal changes in body weight, body energy content, food intake and locomotor activity. Seasonal changes in food efficiency were also evident. 3. The results emphasize the important role of both energy intake and energy expenditure in the regulation process. 4. It can be concluded that regulation of seasonal energy balance is a dynamic process with various interactions between different factors.     

Arginine auxotrophs of Candida albicans deficient in argininosuccinate lyase

Auxotrophic mutants of Candida albicans FC18 were induced by a combination of treatments with nitrous acid and UV irradiation. Arginine (Arg-), histidine (His-) and methionine/cysteine (MetA-) auxotrophs were recovered by this means. The Arg- auxotrophs lacked active argininosuccinate lyase (EC 4.3.2.1), the enzyme catalysing the final step in arginine biosynthesis. Thus the locus may be designated arg-4. The mutant strains bearing this mutation did not form germ tubes unless the germination medium contained arginine.     

The subunit composition of Portunus trituberculatus hemocyanin polymers

The subunit composition of isolated polymeric forms of Portunus trituberculatus hemocyanin were analysed by immunological techniques. The dodecamers contain four monomeric subunits corresponding to subunits I, II, III and IV, whereas the hexamers are devoid of subunit IV. These results suggest that subunit IV is required as a joining piece for the assembly of dodecamers.     

Maleylated-BSA suppresses IFN-gamma-mediated Ia expression in murine peritoneal macrophages

Maleylated bovine serum albumin (maleyl-BSA) and other polyanionic polymers that are recognized by cell surface receptors on macrophages have been shown to induce chemotaxis, protease secretion, and tumoricidal function in this cell type. In this paper the effect of maleyl-BSA on Ia antigen expression has been evaluated. In a fashion similar to LPS, maleyl-BSA suppressed IFN-gamma-induced expression of Ia in a time- and dose-dependent manner. Also like LPS, maleyl-BSA stimulated the production and secretion of substantial amounts of PGE2 over a 24-hr period. This did not, however, appear to be the primary mechanism by which expression of Ia was suppressed, because co-treatment of the cells with indomethacin, which totally inhibited the production of PGE2, only minimally affected the suppressive activity. Surprisingly, the suppressive activity of both maleyl-BSA and LPS could be largely abrogated by co-treatment of the cells with cyclohexamide during the time period when Ia expression was sensitive to suppression. This effect was selective in that PGE2- or dibutyryl cyclic AMP-induced suppression of Ia expression was not affected by cyclohexamide treatment. The data support the concept that there are multiple molecular mechanisms involved in the negative regulation of IFN-gamma-induced Ia expression in macrophages. Such mechanisms may include, in addition to the synthesis of PGE2 and consequent elevation in intracellular levels of cyclic AMP, one or more proteins made early after treatment with either maleyl-BSA or LPS. Thus the function of some of these early gene products may be to regulate expression of functional genes such as that encoding Ia antigen.     

The case for cloud computing in genome informatics

With DNA sequencing now getting cheaper more quickly than data storage or computation, the time may have come for genome informatics to migrate to the cloud.     

Conus-like structure in the eye of the deep-sea teleost Radiicephalus elongatus (Pisces,Teleostei)

Summary A conus-like structure, the hyaloid conus, located on the optic nerve head of the mesopelagic deep-sea teleost Radiicephalus elongatus is described. The hyaloid conus consists of a tapering sheath of unpigmented, vascularized connective tissue enveloping the proximal part of the hyaloid artery which proceeds from the optic nerve head through the vitreous body to the ventrally located falciform process and lens muscles. The hyaloid artery passes through the hyaloid conus without giving off any branches. The conus vessels encircling the hyaloid artery receive arterial blood from the choroid via small arteries and are drained to the choroid by a single vein. The hyaloid conus is compared with the lacertilian conus papillaris. The function of the hyaloid conus is unknown. Because of its small dimensions relative to those of the eyeball and its few capillaries, it is unlikely that the hyaloid conus is a supplemental nutritive device for the retina.     

Cat satellite DNA. Isolation using netropsin with CsCl gradients

The absence of centromeric bands in the karyotype of Felis catus is confirmed. It is also confirmed that no satellite band is visible in CsCl density gradients. However, a satellite is observed both by recentrifuging the fraction of the DNA that bands at high density in CsCl and by using netropsin to enhance the resolution of a CsCl gradient containing total F. catus DNA. The satellite, about 0.5% of total DNA, was isolated by repeated centrifugation in CsCl alone and in CsCl with netropsin. Netropsin was removed and a pure satellite DNA obtained. The reassociation kinetics (C0t1/2 less than 10(-3) M . s) show that the satellite is of the simple sequence type and hence a candidate for centromeric heterochromatin. Its cytological localisation awaits in situ hybridisation experiments.     

Aggregation of tobacco mosaic virus by sodium chondroitin sulfate

The precipitation of tobacco mosaic virus by sodium chondroitin sulfate in an aqueous solution was investigated kinetically by means of turbidimetry. The virus solution became turbid after the addition of chondroitin sulfate. A threshold concentration of chondroitin, 1.33 mg/ml, was required for virus precipitation, irrespective of the virus concentration. The precipitation resulted from a mutual spatial exclusion phenomenon, leading to the separation of the virus as a crystalline phase. The dimension of chondroitin sulfate calculated at the threshold concentration agreed well with that obtained by other methods. The initial slopes and the aggregation half-times of the virus aggregates depended on both chondroitin and virus concentrations and the former increased with the increase in concentration of each. Above the threshold concentration of chondroitin sulfate, tobacco mosaic virus aggregation was a rapid-aggregation process and ended within 100 sec.