Influence of Bacterial Infection on Serum Enzymes of White Rats

Infection of white rats with Francisella tularensis (Pasteurella tularensis) and Salmonella typhimurium and exposure to the endotoxin of S. typhimurium stimulated significant increases in various serum enzymes including aldolase, lactate dehydrogenase, phosphohexose isomerase, isocitrate dehydrogenase, and glutamate-oxalacetate transaminase. The rates of changes in enzymatic activity after infection were directly related to the size of infecting dose and to the type of infective agent employed. Tularemic infection stimulated excessive changes in enzyme activity, whereas salmonellosis and endointoxication elicited less pronounced alterations of relatively short duration. Changes observed in serum enzymes after exposure to these agents reflect the severe liver damage and extensive systemic involvement noted in tularemia as opposed to more localized and less intensive tissue damage occurring during salmonellosis and endointoxication.     

Vocalizatons of chimpanzees in non-caged captivity

1. The chimpanzee vocal system is an emotionally linked vocal response developed on a standard pre-symbolic primate system.
2. Differences in number of sounds recorded by different observers may be due to personal choice, or due actual presence or absence of certain sound types in different living situations. Further research is needed in this case before comparisons can be made.
3. Idiosyncratic use of certain signals may serve as a basis for growth of local dialects in different areas. Spread of such dialects may be related to the amount of respect accorded to dominant animals. More study may shed light on the growth and development of pre-symbolic systems.

     

Cellulose: Energy source for microbial protein

Mixed cultures of bacteria anaerobically attacking cellulosic materials produce sufficient acetic, butyric, lactic and formic acids and ethanol and glucose to account for most of the original carbon. These products contain 60 to 90% of the free energy of the cellulose and are all usable as carbon sources for the aerobic growth of yeast.     

Further Studies on the Lyo and Desmo Components of Several Hydrolytic Enzymes and Their Histochemical Significance

This report describes additional studies of the lyo and desmo components of esterase, alkaline phosphatase, acid phosphatase, leucine aminopeptidase, and β-glucuronidase. The techniques used have already been reported (7). Enzyme diffusion occurs to different degrees in different fixatives, and varies somewhat with each enzyme. Loss of enzymatic activity during fixation occurs as a result of both inactivation due to the chemical reaction of the fixative with the enzymic protein, and diffusion of the lyo component into the fixative. The amount of diffusion into formalin can be reduced by the addition of salts, sucrose, or methocel. The pH of the aqueous medium significantly influences the removal of the lyo fraction from the tissue section. A striking similarity can be noted in the proportions of each fraction of enzyme present in the kidney of the rat, dog, and man. The procedure of fixation and paraffin embedding of tissue blocks does not wholly prevent the diffusion of the lyo component from the tissue sections when they are subsequently immersed in the aqueous incubation medium.     

Direct contact is required between serum albumin and hamster spermatozoa for capacitation in vitro

A dialysis unit was used to test whether direct physical contact between serum albumin and hamster spermatozoa is required for capacitation and/or the acrosome reaction. Sperm and bovine serum albumin (BSA) were incubated cither together (direct incubation) or separated by a dialysis membrane (indirect incubation). Sperm viability was supported with “sperm motility factors” (hypotaurine and epinephrine) and polyvinylalcohol (PVA). Spermatozoa became capacitated and underwent acrosome reactions when directly incubated in medium containing BSA (TALP-PVA), but did not undergo acrosome reactions when indirectly incubated with BSA (medium TLP-PVA). When sperm were first incubated for 4 hr indirectly with BSA, followed by 4 hr direct incubation with BSA, capacitation did not occur during indirect incubation. These findings indicate that an “intimate association” is necessary between serum albumin and spermatozoa to support capacitation under in vitro incubation conditions. The data are consistent with the concept of direct transfer of compounds from sperm to albumin and/or vice versa during sperm capacitation.     

Age determination of Antarctic krill using fluorescence and image analysis of size

Summary The ages of 252 mature female krill, collected from Prydz Bay in January 1985, were determined using length frequency analysis and the fluorescent age pigment (FAP) technique. Results of both methods suggest 6 years classes for adult krill. Correspondence between the ages determined by the two techniques is generally within one year. The animals were also analyzed by a computerized image analysis system, which recorded a large suite of size and shape parameters. The accuracy of discriminant functions constructed to relate the image analysis parameters to age approached 90% for the ages defined by length frequency, and 52% for physiological age.     

Modification of Gs-Stimulated Adenylate Cyclase in Brain Membranes by Low pH Pretreatment: Correlation with Altered Guanine Nucleotide Exchange

Pretreatment of rat brain membranes at pH 4.5 before assay at pH 7.4 modifies the function of GTP-binding proteins (G-proteins) by eliminating Gs-stimulated adenylate cyclase activity while increasing opiate-inhibited adenylate cyclase activity. To help characterize the molecular nature of the low pH effect, we labeled Gs and Gi alpha-subunits in both control and low pH-pretreated membranes with the GTP photoaffinity analog [32P]P3 (4-azidoanilido)-P1-5'-GTP ([32P]AAGTP). When membranes were preincubated with unlabeled AAGTP, a persistent inhibitory state of adenylate cyclase was produced, which was overcome in untreated membranes with high (greater than 1 microM) concentrations of guanylyl-5'-imidodiphosphate [Gpp(NH)p]. In low pH-pretreated membranes, this inhibition could not be overcome, and stimulation by Gpp(NH)p was eliminated. Maximal inhibition of adenylate cyclase achieved by incubation with AAGTP was not altered by low pH pretreatment. Incorporation of [32P]AAGTP into Gs (42 kilodaltons) or Gi/o (40 kilodaltons) was unaffected by low pH pretreatment; however, transfer of 32P from Gi/o to Gs, which occurs with low (10 nM) concentrations of Gpp(NH)p in untreated membranes, was severely retarded in low pH-pretreated membranes. Both the potency and efficacy of Gpp(NH)p in producing exchange of [32P]AAGTP from Gi/o to Gs were markedly reduced by low pH pretreatment. These results correlate the loss of Gs-stimulated adenylate cyclase with a loss of transfer of nucleotide from Gi/o to Gs alpha-subunits and suggest that the nucleotide exchange participates in the modulation of neuronal adenylate cyclase.     

A method for fractionation of cloned protein in recombinantSaccharomyces cerevisiae

In a spheroplasting method which allows the fractionation and quantification of cloned invertase activity in recombinantSaccharomyces cerevisiae cells, the yeast cell is selectively degraded with the enzyme Zymolyase for 60 minutes at 45°C to separate periplasmic proteins from cytoplasmic proteins. Most of the glucose-6-phosphate dehydrogenase (a cytoplasmic marker protein) was found in the cytoplasmic fraction.     

Short-term changes in carbon-isotope discrimination identify transitions between C3 and C4 carboxylation during Crassulacean acid metabolism

Short-term measurements of instantaneous carbon-isotope discrimination have been determined from mass-spectrometric analyses of CO₂ collected online during gas exchange for the epiphytic bromeliad Tillandsia utriculata L. Using this technique, the isotopic signature of CO₂ exchange for each phase of Crassulacean acid metabolism (CAM) has been characterised. During night-time fixation of CO₂ (Phase I), discrimination () ranged from 4.4 to 6.6, equivalent to an effective carbon-isotope ratio (¹³C) of –12.3 to –14.5 versus Pee Dee Belemnite (PDB). These values reflected the gross photosynthetic balance between net CO₂ uptake and refixation of respiratory CO₂, characteristic of CAM in the Bromeliaceae. When for the relative proportion of external (p _a ) and internal (p _i) CO₂ is taken into account, calculated p _i/p _a decreased during the later part of the dark period from 0.68 to 0.48. Measurements of during Phase II, early in the light period, showed the transition between C₄ and C₃ pathways, with carboxylation being increasingly dominated by ribulose bisphosphate carboxylase (Rubisco) as increased from 10.5 to 21.2 During decarboxylation in the light period (Phase III), CO₂ leaked out of the leaf and the inherent discrimination of Rubisco was expressed. The value of calculated from on-line measurements (64.4) showed that the CO₂ lost was considerably enriched in ¹³C, and this was confirmed by direct analysis of the CO₂ diffusing out into a CO₂-free atmosphere ( ¹³C = + 51.6 versus PDB). Instantaneous discrimination was characteristic of the C₃ pathway during Phase IV (late in the light period), but a reduction in showed an increasing contribution from phosphoenolpyruvate carboxylase. The results from this non-invasive technique confirm the observations that double carboxylation involving both phosphoenolpyruvate carboxylase and Rubisco occurs during the transient phases of CAM (II and IV) in the light period.Abbreviations and Symbols CAM Crassulacean acid metabolism - H⁺ (dawn-dusk) variation in titratable acidity - ¹³C carbonisotope ratio of plant organic material, relative to Pee Dee Belemnite (vs. PDB) - discrimination against ¹³CO₂, - p _i, p _a internal, external partial pressures of CO₂ - Rubisco ribulose1,5-bisphosphate carboxylase - PAR photosynthetically active radiation - PEPCase phosphoenolpyruvate carboxylase We are grateful for financial support in respect of research grants (GR3/5360, GR3/6419) and a studentship awarded by the Natural Environment Research Council, UK.