Growth Factors for Mycoplasma pneumoniae in Yeast and Tissue Extracts

1. Many tissue extracts have been shown to have growth factor activity towards M. pneumoniae notably bovine lung. Yeast extract is therefore not unique in this respect. The materials in lung digest and in yeast extract are very similar in properties and could be identical.
2. The growth factor is a low molecular weight water soluble material. Despite its stability to heat it decomposes on storage, presumably by oxidation.
3. Chromatographic procedures, on both Dowex 50W columns and on paper, indicated the presence of two active components.     

Grey seal, Halichoerus grypus, energetics: females invest more in male offspring

Grey seal females transfer large amounts of energy to their pups during the brief lactation period. The costs of lactation have been measured using weight changes of mother and pup pairs. Large females come ashore to give birth earlier in the season and lose weight more rapidly than smaller females. The sex ratio of Grey seal pups born is skewed towards males in the early part of the breeding season. Male pups are larger at birth and gain weight more rapidly than female pups, and their mothers show a correspondingly faster rate of weight loss than mothers of female pups. The energy costs of gestation and lactation to a Grey seal mother are 31 GJ for male pups and2–8 GJ for female pups. Males are therefore 10% more costly in energy terms to raise to weaning. Because, on average, large females arrive at breeding sites before smaller animals, biased results on weight changes would be obtained from methods which do not use repeated weighings. We suggest that the high efficiencies of lactation estimated for Harp seals compared with other phocid seals could be accounted for by such a bias.     

Immunological Reactions of Single Pollen Grains, Electrophoresis and Enzymology of Pollen Protein Exudates

Single intact pollen grains of Oenothera organensis, when placedupon a thin layer of agar containing pollen antiserum, producecircular areas of precipitate. Pollen grains from an S₂S₂ plantdo not produce precipitate in S₆ antiserum. Pollen grains froman S₆S₆ plant and an S₂'S₄' self-compatible plant produce precipitatesin S₆ antiserum. Fifty per cent of the pollen grains from anS₂S₆ plant produce precipitate in S₆ antiserum. Protein diffusesinto buffer solutions from intact pollen grains within 212 min.As much as 40 per cent of the total protein diffuses out inan hour. Amylase and invertase were detected in the diffusatefrom pollen grains. Alkaline and acid phosphatases were confinedto the pollen grains and did not diffuse out. The serologicalprecipitates are specific to the incompatibility system.     

Investigation of the Regulation of Pigmentation in α-Melanocyte-Stimulating Hormone Responsive and Unresponsive Cultured B16 Melanoma Cells

In vitro melanocyte-stimulating hormone (MSH) stimulates melanogenesis in some, but not all, melanocytes and melanoma cells. In an attempt to explain this variation in response to αMSH, we examined cyclic adenosine monophosphate (cAMP) accumulation, tyrosinase activity, and melanin production in primary (1°) murine B16 melanoma cells and in two B16 cell lines (B16 F1 and B16 F10) that are known to respond to αMSH. In vivo all three B16 melanoma cell types produced pigmented tumours. In vitro αMSH increased tyrosinase activity and melanin content in the F1 and F10 cells but not in the B16 1° cells. αMSH, however, increased cAMP production in all three cell types, confirming that the inability of B16 1° cells to produce melanin in response to αMSH is not due to a lack of αMSH receptors or cAMP response to αMSH. Further, we present evidence for a separate pathway of melanogenesis that is independent of cAMP as calmodulin antagonists, which do not elevate cAMP, increased tyrosinase activity, and melanin production in both 1° and F1 cells.     

α-MSH and Melanogenesis in Normal Human Adult Melanocytes

Normal human skin melanocytes do not pigment consistently to α-melanocyte stimulating hormone (α-MSH) in culture. The aim of this study was to establish media conditions in which to obtain a reproducible melanogenic response to α-MSH in these cells. Twenty-five media of varying mitogen composition were examined. As previously noted by other workers, melanocyte morphology and proliferation are greatly affected by media composition. However, under the majority of media conditions that supported melanocyte survival and proliferation, cells did not respond to α-MSH with any consistent increase in dopa oxidase activity or melanin content. In only one medium condition, where basic fibroblast growth factor (bFGF) was the sole mitogen present, α-MSH induced both an increase in dopa oxidase activity (at 48%) and in melanin content (of 283%).     

A re-examination of Lepidostrobus Brongniart

Lepidostrobus is a genus that was established by Brongniart for Palaeozoic lycopod cones. Since then the genus has been used for a variety of cones that have similar characters. There is now compelling evidence that the genus represents a heterogeneous group of monosporangiate and bisporangiate cone species and that it should be divided. Lepidostrobus is rediagnosed as a genus of microsporangiate cones. Ftemingites Carruthers is rediagnosed as a genus of those bisporangiate cones formerly included in Lepidostrobus.     

The wound healing and haemocyte response in the skin of the lesser octopus Eledone cirrhosa (Mollusca: Cephalopoda) in the presence of Vibrio tubiashii

The sequential response of wound closure in the skin of the lesser octopus Eledone cirrhosa is described following experimentally induced infections by the Gram-negative bacterium, Vibrio tubiashii. Results show that the post-infection healing response varied considerably from the response observed in non-infected wounds reported previously. Prominent among the findings was the much more extensive haemocyte response noted throughout healing when compared with non-infected wounds. In addition, there was a generalized inhibition of epidermal migration so that wound closure was never completed during the experiment. The presence of a 'double tier' amorphous zone was evident at certain stages of the healing response and the implications of this finding in relation to post-infection wound closure is discussed.     

Enzymes of the Glyoxylate Cycle in Chlorella vulgaris

The detection and assay of the enzymes of the glyoxylate cyclein Chlorella are described. The activity of the enzymes in cellsgrown on acetate is about adequate to account for the rate ofgrowth with acetate as sole carbon source. Isocitratase activity increases markedly when cells are incubatedwith acetate in darkness; malate synthetase activity also increasesbut the activity of the other enzymes is unaffected. Isocitrataseactivity does not increase when glucose is added as well asacetate or the cells are illuminated and supplied with carbondioxide. When cells are given acetate as sole carbon sourcethere is a lag of 24 hrs. before cell division begins; duringthis period, isocitratase activity increases greatly.