Chemotaxonomic features of lipophilic components inAdesmia species (Leguminosae)

Studies were performed on GC-MS to assess the lipophilic composition of sixAdesmia species representing two subgenera and three series. Normal fatty acids and hydrocarbons were mainly found, as well as acetylenic compounds, dibasic acids, cyclic hydrocarbons, high molecular weight alcohols and one sterol.     

Free sterols of the red alga Gigartina skottsbergii

The free sterols of the red alga Gigartina skottsbergii have been identified by means of GC and GC/MS analyses. The mixture contained saturated and unsaturated C²⁷, C²⁸ and C²⁹ sterols. The major component was cholest-5-en-3β-ol. Cholesta-5,24-dien-3β-ol (desmosterol) was present in low proportion but no side chain hydroxylated components were detected.     

TEMPERATURE,PHOTOPERIOD AND LIGHT INTERACTIONS ON GROWTH AND FERTILITY OF GLOSSOPHORA KUNTHII (PHAEOPHYTA,DICTYOTALES) FROM CENTRAL CHILE1

Excised ligulae of Glossophora kunthii from central Chile were cultured of temperatures of 5–25° C, photoperiods of 16:8 and 8:16 h LD cycles, with photon irradiances of 10 and 50 μmol · m^?2· s^?1. Growth of the ligulae, number of fertile ligulae and number of tetrasporangia forming on the ligulae were assessed. Ligulae tolerated temperatures between 10 and 23°C. Temperature interacted with daylength and photon dose, determining quantitative responses in the growth and fertility of ligulae. Growth was least at 8:16 h LD and was not affected significantly by temperature. It was greatest at 16:8 h LD, 50 μmol · m^?2· s^?1 and increased with temperature up to 20°C. Percentage of fertile ligulae and number of tetrasporangia increased with temperature at the 8:16 h LD cycle, reaching a maximum at 20°C. Fertility was low at 16:8 h LD, except at 20° C (and low photon dose) suggesting that reproduction at 20° C is independent of daylength in this species. Ligulae grew larger at the long-day photoperiods and the proportions of fertile ligulae were higher at the short-day photoperiods, irrespective of the total photon dose received. These results suggest that some aspects of growth and fertility are controlled by photoperiod.     

Nuclear import of Ran is mediated by the transport factor NTF2

A concentration gradient of the GTP-bound form of the GTPase Ran across nuclear pores is essential for the transport of many proteins and nucleic acids between the nuclear and cytoplasmic compartments of eukaryotic cells [1], [2], [3] and [4]. The mechanisms responsible for the dynamics and maintenance of this Ran gradient have been unclear. We now show that Ran shuttles between the nucleosol and cytosol, and that cytosolic Ran accumulates rapidly in the nucleus in a saturable manner that is dependent on temperature and on the guanine-nucleotide exchange factor RCC1. Nuclear import in digitonin-permeabilized cells in the absence of added factors was minimal. The addition of energy and nuclear transport factor 2 (NTF2) [5] was sufficient for the accumulation of Ran in the nucleus. An NTF2 mutant that cannot bind Ran [6] was unable to facilitate Ran import. A GTP-bound form of a Ran mutant that cannot bind NTF2 was not a substrate for import. A dominant-negative importin-β mutant inhibited nuclear import of Ran, whereas addition of transportin, which accumulates in the nucleus, enhanced NTF2-dependent Ran import. We conclude that NTF2 functions as a transport receptor for Ran, permitting rapid entry into the nucleus where GTP-GDP exchange mediated by RCC1 [7] converts Ran into its GTP-bound state. The Ran–GTP can associate with nuclear Ran-binding proteins, thereby creating a Ran gradient across nuclear pores.     

Parental behaviour in the Mongolian gerbil (Meriones unguiculatus). I. Retrieval

Twelve pairs of Mongolian gerbils rearing 15 litters were tested for their responses to their own pups placed outside the nest area. All females and 3 of 12 males retrieved pups. Fewer pups were retrieved and more returned to the nest by themselves as the pups matured. The female's latency to retrieve pups also increased as the pups grew older. Due to retrieval by both parents and the spontaneous return of pups, few pups were left outside the nest after scattering. The possible mechanisms by which parental retrieval is elicited are discussed.     

High performance liquid chromatography and UV detection for the separation and quantitation of prostaglandins

A fast and reliable method for the separation and quantitation of arachidonic acid metabolites PGF_1α, PGF_2α, PGD₂, PGE₁, PGE₂, PGB₂, PGA₂, 6-keto PGE₁, 6-keto PGF_1α, T×B₂ and 15-keto PGE₂ by high-performance liquid chromatography has been developed. Utilizing a single reverse-phase column and a UV spectrophotometer, sensitivity as little as 30 nanograms of each of these prostaglandins can be separated and subsequently detected. Although this study was performed using standards, it is highly promising for future application to biological fluids.     

Activity,extraction and stability of enzymes involved in polysaccharide biosynthesis in Citrus

The effects of EDTA, 2-mercaptoethanol and bovine serum albumin on the extraction and stability of hexokinase, phosphoglucomutase, UDPglucose pyrophosphorylase and 1,3-β-glucan synthase from Mexican lime bark have been examined. The activity of these enzymes was generally increased and stability was tested in refrigerated and frozen extracts. Bovine serum albumin was the best stabilizing agent for phosphoglucomutase and 1,3-β-glucan synthase, but the former was more stable in refrigerated and the latter in frozen extracts. UDPglucose pyrophosphorylase stability was strongly dependent on the presence of 2-mercaptoethanol. The fact that the activity of 1,3-β-glucan synthase is the lowest of the four enzymes even in the presence of optimal concentrations of its activator strongly suggests that it is the key enzyme in the regulation of the metabolic pathway.     

Presence of skin permeability factors in the extracellular products ofYersinia ruckeri

In this study we have demonstrated the presence of permeability factors (PF) in the extracellular products (ECP) of 16 strains of the bacterial fish pathogenYersinia ruckeri. The production and detection of these factors were dependent on the growth media and the ECP extraction procedure. The best results were obtained with a cellophane plate method and use of brain-heart infusion agar (BHIA) medium. The loss of necrotizing activity after heating the samples at 80°C for 15 min indicates the thermolabile nature of the toxin. In addition, this activity was not correlated with the production of hemolysins and cytotoxins by theY. ruckeri strains.     

Characteristics of antibodies to guinea pig (Na++K+)-adenosine triphosphatase and their use in cell-free synthesis studies

Summary Antibodies have been produced, in three rabbits, to Na/K-ATPase purified from guinea pig renal outer medulla. Each rabbit produced antibodies to both the (catalytic) and the (glycoprotein) subunits of Na/K-ATPase. The titers of the anti- and anti- antibodies varied with time and between rabbits. None of the antisera inhibited Na/K-ATPase activity under various preincubation conditions. A method is presented for separating small amounts of anti- subunit from anti- subunit antibodies. There was not cross-reactivity of antibodies to one subunit with the other subunit. The subunit of the Na/K-ATPase was cleaved into a 41,000-dalton peptide (that contains the ATP phosphorylating site) and a 58,000-dalton hydrophobic peptide as described by Castro and Farley (Castro, J., Farley, R.A., 1979,J. Biol. Chem. 254:2221–2228). Anti- antibodies from all of the rabbits reacted with both proteolytic fragments. The anti-guinea pig Na/K-ATPase antisera (pooled) cross-reacted with the subunit of Na/K-ATPase from human, cow, dog, rabbit, rat mouse, turtle, and toad; and with the subunit from human, rat, and mouse. The loci of cross-reactivity were investigated using partially purified canine kidney Na/K-ATPase cleaved with trypsin as described above. The antisera from rabbits 1 and 2 cross-reacted with the 41,000-dalton peptide from the dog but very little with the 58,000-dalton peptide. No cross-reactivity was observed with antiserum from rabbit 3 to either fragment. Guinea pig kidney RNA was translated in a rabbit reticulocyte lysate system followed by immunoprecipitation with the antisera. The molecular weight of the cell-free synthesized chain was 96,000 daltons. Its identity was established with purified anti- antibodies and by immunocompetition with purified Na/K-ATPase and Ca-ATPase. Translation of the subunit was not detected in this system.