The interaction of yeast citrate synthase with yeast mitochondrial inner membranes

The specific interaction of yeast citrate synthase with yeast mitochondrial inner membranes was characterized with respect to saturability of binding, pH optimum, effect of ionic strength, temperature response, and inhibition by oxalacetate. The binding ability of the inner membranes is inhibited by proteolysis and heat treatment, which implies that the membrane component(s) responsible for binding is a protein. A protein fraction from inner membranes when added to liposomes will bind citrate synthase. In addition, the binding of yeast fumarase, mitochondrial malate dehydrogenase, and cytosolic malate dehydrogenase to yeast inner membranes was examined. For these studies the yeast mitochondrial matrix enzymes, citrate synthase (from two types of yeast), malate dehydrogenase, and fumarase, as well as cytosolic malate dehydrogenase, were purified using rapid new techniques.     

Development of the nervous system of the pluteus larva of Strongylocentrotus droebachiensis

Summary Development of the nervous system of the pluteus larva of Strongylocentrotus droebachiensis was investigated using indirect immunofluorescence with antibodies against dopamine, GABA, and serotonin, and glyoxylic acid-induced fluorescence of catecholamines. Serotonergic cells first appear in full gastrulae; dopaminergic and GABAergic cells are present in early four-arm plutei. The number of neurons and the complexity of the nervous system increases through development of the pluteus. In the pluteus the dopaminergic component of the nervous system includes a ganglion in the lower lip of the mouth and a pair of ganglia at the base of the post-oral arms which extend axons along the base of the circumoral ciliary band. The distribution of cells visualized by glyoxylic acid-induced fluorescence is similar to that of dopaminergic cells. GABAergic neurons occur in the upper lip and in the wall of the esophagus. Serotonergic neurons are present in the lower lip; the pre-oral hood contains an apical ganglion which extends axons along the base of the epidermis overlying the blastocoel. The dopaminergic and GABAergic components of the nervous system are associated with effectors involved in feeding and swimming. The serotonergic component is not associated with any apparent effectors but may have a role in metamorphosis.     

Effect of Moniliformis moniliformis density on distribution within the definitive host population (Rattus norvegicus)

The population dynamics of Moniliformis moniliformis was studied in ‘free-ranging’ laboratory rats, Rattus norvegicus, presented with different relative density levels of M. moniliformis in cockroaches, Periplaneta americana. Changes in selected population parameters of the negative binomial distribution were evaluated as indicators of changes in aggregation. A significant increase in the degree of aggregation of parasites occurred as a result of the increase in relative density of infective stages available to the rats. This increase in aggregation was due to the increase in over-dispersion that occurred in female rats only. The degree of aggregation in females was found to be significantly higher than that in males at both treatment levels. The best indicators of the degree of aggregation were found to be the ratio of the variance to the relative density and the ratio of the log-variance to log-relative density. Changes in k were not correlated with changes in over-dispersion or the relative density.     

Gut fungi

Herbivores consume large quantities of cellulose and other plant cell wall (fibre) carbohydrates yet generally lack the enzymes to digest them. This has led to the evolution of specialized portions of the gut, such as the rumen and caecum, which contain large populations of digestive anaerobic microorganisms. Diverse bacteria and protists from this environment have been studied for over a hundred years but it is only recently that a significant population of highly specialized flagellate fungi have been identified. These fungi are important in fibre digestion. Their diversity, properties, activities, phylogeny and possible economic significance are the subjects of this review.     

Recovery of plants from leaf protoplasts of hybrid-poplar and aspen clones

Leaf protoplasts were isolated from shoot cultures of two hybrid poplar clones (Populus alba × P. grandidentata Crandon, NC-5339 and P. nigra Betulifolia × P. trichocarpa, NC-5331) and the Upright European Aspen (P. tremula Erecta) and were cultured in contact with screen discs floated in liquid medium. Protoplast culture was influenced by the growth medium of the source shoot cultures, the protoplast purification procedure, the plating density, and the presence or absence of a coconut water and casein hydrolysate supplement added to the culture medium. The protoplast-derived cells divided more quickly and with higher incidence than previously reported for hybrid poplars. Shoots were regenerated from the protoplast-derived calli and were maintained as shoot cultures. Plants were developed from microcuttings rooted ex vitro and were grown-on in the greenhouse and field.Abbreviations BA benzyladenine - NAA 1-naphthaleneacetic acid - TDZ thidiazuron - WPM Woody Plant Medium, Lloyd and McCown (1980) - MS Murashige and Skoog Medium (1962) - NC-XXXX North Central Forest Experiment Station accession number assigned to hybrid poplar clones.     

Effects of naloxone-precipitated withdrawal after a single dose of morphine on catecholamine concentrations in guinea-pig brain

The effect of naloxone-precipitated withdrawal after acute morphine was studied on the concentrations of noradrenaline (NA), 4-hydroxy-3-methoxyphenylethyleneglycol (MHPG), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and on the metabolite/parent amine ratios MHPG/NA, DOPAC/DA and HVA/DA, in eight regions of the guineapig brain. Guinea-pigs were treated with a single dose of morphine sulphate (15 mg/kg s.c.) or saline (control) and 2h later with naloxone hydrochloride (15 mg/kg s.c.) to precipitate withdrawal. The animals were decapitated at 0.5 h or 1 h after naloxone injections and their brains analysed for monoamine concentrations by HPLC-ECD. At 0.5 h after naloxone-precipitated withdrawal NA and MHPG levels, and the MHPG/NA ratio, were increased in the hypothalamus, and the NA levels were increased in the hypothalamus, medulla/pons and cortex 1 h after naloxone. Naloxoneprecipitated withdrawal also produced increased DA metabolism in the cortex, midbrain and medulla 0.5 h later, and in the cortex, hypothalamus and striatum 1 h later. Hence naloxone-precipitated withdrawal from acute morphine treatment produced a complex pattern of increased synthesis and metabolism of NA and DA which varied over time and with the brain region examined.     

Improved preservation of the form and contents of wall vesicles and the golgi apparatus in freeze substituted hyphae ofSaprolegnia

Summary Secretory vesicles involved in cell wall synthesis (wall vesicles) and the Golgi apparatus have been compared in conventionally fixed and freeze substituted hyphae of the oomycete fungusSaprolegnia ferax. Wall vesicles freeze substituted in various fluids range from spherical to tubular and contain an intensely staining, phosphorous rich matrix. In contrast diverse conventional fixations cause artefactual constrictions in most tubular vesicles and loss of their intensely staining contents. These data are interpreted to show the existence of an intravesicular skeletal system, with cellular regulation, to determine vesicle morphology and intravesicular synthesis of a hypothetical phosphorylated glycolipid cell wall precursor. Whilst freeze substitution gives superior preservation of wall vesicle morphology, it does not demonstrate any preferential association between wall vesicles and microtubules thus suggesting that microtubules are only indirectly involved in wall vesicle transport. Freeze substitution is superior to conventional fixation for analysis of the Golgi apparatus because it uniquely reveals both differentiation of a specific single cisterna in each Golgi body and greater differences in membrane thicknesses throughout the endomembrane system.     

Blood characteristics of white-tailed deer from northeastern Kansas

Blood samples were collected from 118 white-tailed deer (Odocoileus virginianus) shot on the Fort Riley Military Installation in northeastern Kansas. Values for these deer for hematocrit, glucose, alkaline phosphatase, uric acid, total protein, albumin, and calcium were within the ranges reported in previous studies for undrugged white-tailed deer. Abnormally high concentrations of serum glutamic oxaloacetate transaminase (SGOT) and lactic dehydrogenase (LDH) were attributed to general trauma and tissue damage caused by shooting the deer. Fawns had higher concentrations of alkaline phosphatase than adults and had lower concentrations in winter than at other times of the year. Serum urea nitrogen (SUN) concentrations fluctuated seasonally. Elevated concentrations of SUN in adult males killed in December were attributed to an increased catabolism of muscle protein caused by low dietary intake and high energy requirements during the rut. Cholesterol concentrations varied seasonally without regard to age or sex.