Decreased brown adipose tissue thermogenic activity following a reduction in brain serotonin by intraventricular p-chlorophenylalanine

The effects of reducing brain serotonin (5-HT) levels by means of intracerebral-ventricular injections of the tryptophan antagonist p-chlorophenylalanine (PCPA) were investigated in male rats. Six days after the operation, PCPA-treated rats, either fedad libitum or pair-fed to the food intake of control rats, showed decreased thermogenic activity and capacity in their interscapular brown adipose tissue (BAT) and also increased fat storage in their white adipose tissue (WAT). These results indicate that serotonergic synapses might play a regulatory role in the sympathetic control of BAT thermogenesis and in the rate of WAT deposition (by an as yet unidentified mechanism), in addition to their well established role in controlling food intake.     

An enzyme with properties similar to those of beta-N-acetylhexosaminidase S is expressed in the promyelocytic cell line HL-60.

Extracts of the human promyelocytic cell line HL-60 contain a form of beta-N-acetylhexosaminidase that is not retained on columns of benzeneboronate-agarose ('phenylboronate-agarose') and has a pI value lower than that of beta-N-acetylhexosaminidase A. It is clearly distinct from beta-N-acetylhexosaminidase A in its behaviour on DEAE-cellulose columns, and it requires a higher concentration of salt for its elution. This 'extra' form has a higher ratio of activity towards 4-methylumbelliferyl beta-N-acetylglucosaminide 6-sulphate and 4-methylumbelliferyl beta-N-acetylglucosaminide than has beta-N-acetylhexosaminidase A and is less stable when heated at 50 degrees C. It has a pH optimum of 4.5 and is therefore not beta-N-acetylglucosaminidase C. Anti-(human beta-N-acetylhexosaminidase alpha-subunit) serum precipitated both beta-N-acetylhexosaminidase A and the 'extra' form, whereas an anti-(beta-subunit) serum precipitated beta-N-acetylhexosaminidase A but not the 'extra' form. Western blotting and immunodetection of polypeptides derived from the 'extra' form revealed a band corresponding in size to mature alpha-subunits. On the basis of this and of its behaviour on isoelectric focusing, chromatofocusing and its kinetic properties, we conclude that the 'extra' form is composed of alpha-subunits and resembles beta-N-acetylhexosaminidase S, the residual form in Sandhoff's disease.     

Expression of mRNA encoding basic fibroblast growth factor (bFGF) in bovine corpora lutea and cultured luteal cells.

A radiolabelled cRNA was synthesized using a 1.4 kb cDNA complementary to mRNA encoding bovine basic fibroblast growth factor (bFGF) as a template, and used as a probe to investigate the expression of mRNA encoding bFGF in bovine ovarian tissue, and luteal cells in primary culture. Northern analysis of poly(A +)RNA prepared from follicles and corpora lutea of various stages revealed a major mRNA species of 7 kb in corpora lutea of all stages, the amount of which was higher late in the luteal phase. No hybridizable message was detectable in follicles of any size. When luteal cells were established in primary culture, expression of the 7 kb mRNA species was maintained. This expression was increased markedly when cells were treated with LH/hCG or Bt2cAMP. Prostaglandin F-2 alpha treatment caused a marked decrease in the basal content of this 7 kb mRNA, and also severely impaired the ability of LH to stimulate this expression.     

The sucrose fuel cell: Efficient biomass conversion using a microbial catalyst

Sucrose was used as a fuel in a thionine-mediated microbial fuel cell containingProteus vulgaris serving as the biocatalyst in the anode compartment. The measured yields show that under suitable conditions the substrate may be oxidised quantitatively to electricity and carbon dioxide.     

Epidemiological characteristics of platelet aggregability.

The epidemiological characteristics of platelet aggregability were established in 958 participants in the Northwick Park Heart Study. The main analyses were based on the dose of adenosine diphosphate at which primary aggregation occurred at half its maximum velocity. Aggregability increased with age in both sexes, was greater in whites than blacks (particularly among men), and tended to decrease with the level of habitual alcohol consumption. Aggregability was, however, greater in women than men and in nonsmokers than smokers. There was no relation between aggregability on the one hand and obesity, current or past oral contraceptive use, menopausal state, or blood cholesterol and triglyceride concentrations on the other. Aggregability was somewhat, though not significantly, higher in men with a history of ischaemic heart disease and in those with electrocardiographic evidence of ischaemia than in those without. There was a strong association between the plasma fibrinogen concentration and aggregability. The widely held concept of platelet aggregability and its implications is probably an oversimplification. In the prevention of thrombosis it may be as useful to consider modifying external influences on platelet behaviour, such as plasma fibrinogen concentration or thrombin production, as it is to rely solely on platelet active agents.     

Larval development and metamorphosis in the marine pulmonate Amphibola crenata (Mollusca: Pulmonata)

The development of the free-swimming veliger of Amphibola is followed from hatching to settlement, and the larval structures compared with those of post-metamorphic juveniles and adult snails. Observations of living specimens and light-microscope sections were combined with scanning electron microscopy to build up a composite picture of veliger structure.
Four stages in the development of veligers are recognized, each being characterized by the appearance of organ systems such as the mantle cavity, larval heart, adult heart and kidney, and larval pallial gland. At or after metamorphosis, the larval systems (heart, kidney and pallial gland) disappear, and the developing adult organs move to the positions characteristic of adult snails.
Organogenesis in Amphibola veligers is compared with that of prosobranch and opisthobranch larvae, and with that of pulmonate larvae with direct development. The closest similarity is seen to be with opisthobranch veligers.     

The influence of changing temperature on the life history of Daphniopsis ephemeralis

We present evidence which suggests that for Daphniopsis ephemeralischanges in water temperature may directly cue changes in sexratio, ephippial and parthenogenetic egg production and indirectlydetermine female body size. Field data suggested that over anannual cycle, a population of D. ephemeralis comprised animalswith three distinct life history phases. The first was madeup of exephippial females which hatched in the fall. They produceda second group made up of large parthenogenetic females whichcould produce more than one overwintering generation. In thespring these parthenogenetic females gave rise to a third lifehistory phase which comprised males and small ephippial females.Field enclosure experiments suggested that the small size ofspring females was not related to predation. Laboratory experimentssuggested that ephippial egg production at small body sizeswas associated with ‘increasing’ temperature. Theseexperiments also suggested that the fall reproductive pattern(parthenogenetic eggs and large body sizes) was associated with‘decreasing’ temperatures. We conclude that directionalityof seasonal temperature change may be the prime factor responsiblefor D. ephemeralis life history changes observed in the field.     

Properties and attempted culture of Pasteuria penetrans, a bacterial parasite of root-knot nematode (Meloidogyne javanica)

When they were subjected to a range of physical and chemical treatments, spores of Pasteuria penetrans showed properties similar to those of other endospore-forming bacteria. The spores did not take up some stains, were resistant to desiccation and sonication and showed extrusion of spore contents ('spore popping') on prolonged exposure to 0.1% KMnO₄ in 0.3 n HNO₃. Calcium and dipicolinic acid (DPA) were present at concentrations of 0.28% and 0.96% of the spore dry weight respectively, giving a Ca: DPA molar ratio of 1.2. The infectivity of P. penetrans spores was reduced to a low level after heating at 100°C for 5 min, but spore attachment was not markedly affected by heating at 100°C for 15 min. Evidence for the presence of catalase in P. penetrans spores was equivocal because the low levels of catalase activity observed in spore suspensions may have been due to contamination from catalase-positive nematode tissue. When P. penetrans spores were exposed to a range of substances known to act as germinants for spores of Bacillus spp., germination or loss of refractility was not observed by phase microscopy. In vitro culture of P. penetrans was attempted by inoculating either spores or vegetative mycelial bodies onto a diverse range of simple and complex media and incubating them in aerobic, reduced oxygen, anaerobic and increased CO₂ environments. Signs of spore germination or growth of vegetative stages were never observed.