Dimethyl sulfoxide: A solvent for cytokinins in theAmaranthus bioassay

Dimethyl sulfoxide present in the agar medium at concentration 0.2 % (v/v) and lower does not inhibit cytokinin-induced betacyanin synthesis in theAmaranthus caudatus seedlings. The activity of kinetin, N⁶-(Δ²-isopentenyl)adenine andtrans- zeatin is the same when these cytokinins are dissolved in either water or dimethyl sulfoxide and incorporated into the medium after autoclaving. A simple method is described which allows the cytokinin activity of slightly water-soluble and thermolabile compounds,e.g. aromatic urea and thiourea derivatives, to be determined in theAmaranthus bioassay.     

Biosynthetic approach to the structure of F1-ATPase (BF1 factor) from Micrococcus lysodeikticus membranes: in vivo labeling of the polypeptides and study of their relationship

The F₁-ATPase or BF₁ factor was purified from Micrococcus lysodeikticus substrain B grown in a synthetic medium in the presence of tritiated amino acids. When analyzed in sodium dodecyl sulfate-7% polyacrylamide gels, the fresh purified preparation contained α, β, γ subunits (referred as the intrinsic subunits) and two other polypeptides (designated as X and component of relative mobility 1.0) whose status as subunits remains to be established. This overall polypeptide composition was similar to that of the F₁-ATPase isolated from the same strain grown in complex medium (J. Carreira, J. M. Andreu, M. Nieto, and E. Muñoz., 1976 Mol. Cell. Biochem.10, 67–76). The distribution of ³H-labeled amino acids into purified F₁-ATPase and its constituent polypeptides under different stages of growth was used to investigate the biosynthetic relationship between the different polypeptides. The incorporation of amino acids into purified BF₁ factor was slower than that of cytoplasmic and other membrane proteins. In isotope-dilution and chase experiments, F₁-ATPase showed one of the slowest rates of decay of the incorporated label. These results point out that F₁-ATPase of M. lysodeikticus undergoes slower turnover than the overall cytoplasmic and membrane proteins. Pulse and chase experiments allowed us to conclude that the α, β, γ subunits and the components of relative mobility 1.0 are independent with differences in their turnover and therefore do not bear any apparent relation as precursors-products. The two major subunits represent seemingly the “core” of ATPase, the β subunit behaving like the most stable component. On the other hand, the γ subunit appears to be synthesized independently from this α + β complex.     

Some cellular immune reactions in infants. MIF,E-rosette formation and changes in nucleolar morphology

The cellular immune response (MIF, E-rosette formation and changes in nucleolar morphology of lymphocytes) was followed as related to age and antigenic stimulation. MIF in healthy infants increased from the 2nd to the 12th week of life as compared with the first week, probably due to BCG vaccination. The total and active E-rosette formation did not change during the whole period of investigation. Ring-shaped nucleoli increased gradually from the second week of life. Active nucleoli increased up to the 4th week,i.e. after BCG vaccination and then slowly decreased. Micronucleoli being high in the first week, decreased during 24 weeks of life. After artificial colonization of the intestine the production of MIF was slightly lower in colonized infants than in controls from the 2nd to the 12th week. The other parameters followed were not influenced by colonization.     

Some new species of Penicillium recovered from the atmosphere in Madrid and from other substrata

Six new species ofPenicillium Linkex Fries are described and illustrated. Four of them have been recovered from the atmosphere in Madrid, Spain, the other two species were isolated from must and from soil respectively. They clearly differ from all species of the genus described so far and are, therefore described and proposed as new taxa:Penicillium gerundense sp. nov.,Penicillium valentinum sp. nov.,Penicillium alicantinum sp. nov.,Penicillium malacaense sp. nov.,Penicillium tarraconense sp. nov., andPenicillium vasconiae sp. nov.     

Four new species of Penicillium isolated from the air

Four new species of Penicillium Link ex Fries are described and illustrated. All of them but one have been isolated from the atmosphere in Madrid, Spain. They clearly differ from all species of the genus described so far and are, therefore, described and proposed as new taxa: Penicillium aurantio-flammiferum sp. nov., Penicillium gallaicum sp. nov., Penicillium granatense sp. nov., and Penicillium ilerdanum sp. nov.     

Air-borne fungi in the air of Barcelona (Spain). IV. Various isolated genera

During a two-year survey on the air-borne fungi in the atmosphere of Barcelona (Spain), the following genera were isolated in decreasing order: Aureobasidium, Rhizopus, Mucor, Arthrinium, Phoma, Fusarium, Trichoderma, and Botrytis.     

Morphological changes in strains of Aspergillus flavus link ex fries and Aspergillus parasiticus speare related with aflatoxin production

Two strains ofAspergillus flavus Linkex Fr. and two strains ofA. parasiticus Speare were cultured on crushed moist wheat (Triticum durum var. Pané no. 247) for aflatoxin production studies in correlation with morphological changes. The toxicogenic strains were adapted to the substratum by means of successive transfers at regular intervals (72 h.)The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing. The decrease was accompanied by marked morphological changes. One of the strains studied,A. flavus NRRL 3251, lost completly the capacity of aflatoxin synthesis after several subcultures, presenting at the same time strong morphological variations.A. flavus CBS 120.62 also lost its toxicogenicity after six subcultures.     

Muscle fibrillation caused by cytochalasin-B applied to the motor nerve.

Cytochalasin-B, a drug known to interfere with axoplasmic transport, evoked fibrillary potentials in the geniohyoid muscle when applied to its motor nerve. Despite this denervation-like effect, neuromuscular transmission remained normal. Some contractile characteristics of the muscle were studied. It was found that contraction time, isometric twitch tension, and half-relaxation time were not altered by the drug treatment. The present findings show that neurogenic molecular factors conveyed by axoplasmic transport to the nerve terminal are involved in the regulation of some muscle membrane characteristics but do not modify the muscle contractile features.