Main kinetic characteristics of acetylcholinesterase from brain of Hypostomus punctatus,a Brazilian bentonic fish (cascudo)

• 1.1. A potentiometric method for the assay of cholinesterase has been proposed and compared with a colorimetric assay.
• 2.2. Main kinetic parameters of cholinesterase from Hypostomus punctatus brain were determined indicating that true acetylcholinesterase is by far the predominant enzyme in the brain of this fish.
• 3.3. We have compared our data with published results described from other fish species.
• 4.4. The enzyme inhibition achieved after 3 hr incubation of brain homogenates with ethyl-parathion have indicated that this enzyme shows a characteristic organophosphorous sensitive behavior.

     

Subcellular distribution of metals within the kidney of the bivalve Mercenaria mercenaria (L.)

• 1.1. The subcellular distribution of nine transition metals (plus four additional elements) was measured in the kidney tissue of the quahog, Mercenaria mercenaria.
• 2.2. Elemental analyses of the subcellular fractions indicated three main patterns of metal distribution within kidney cells.
• 3.3. Barium, iron, manganese and lead were associated primarily with kidney granules.
• 4.4. Cadmium, copper, potassium and magnesium were found mainly in the cytosolic fraction.
• 5.5. Calcium, phosphorus and zinc were found in all isolated fractions, probably reflecting the important roles that these elements play in bivalve metabolism.
• 6.6. The organelle composition of the isolated subcellular fractions was determined using marker enzyme assays and microscopic techniques.

     

The regulation of glucose 6-phosphate dehydrogenase from Dicentrarchus labrax (bass) liver

• 1.1. Kinetic constant values of the reaction catalyzed by bass liver glucose 6-phosphate dehydrogenase show to be modified between 10 and 40°C.
• 2.2. The Arrhenius plot between 10 and 50°C shows two slopes with different activation energies.
• 3.3. These results suggest a regulation of this enzyme by environmental temperature.
• 4.4. Kinetics of ATP inhibition were examined between pH 6.2 and 7.8: patterns and K_i values obtained are affected by the pH variation.
• 5.5. NADH is an effective inhibitor of bass glucose 6-phosphate dehydrogenase but this enzyme does not show NAD-linked activity.
• 6.6. Kinetics of pyridoxal 5′-phosphate inhibition have indicated the presence of a lysine in the catalytic site for NADP⁺.

     

Purification and some properties of an atypical alkaline p-nitrophenylphosphate phosphatase activity from Halobacterium halobium

• 1.1. An alkaline p-nitrophenylphosphate phosphatase has been purified 440-fold from extracts of Hatobacterium halobium.
• 2.2. The enzyme has an apparent molecular weight of 24,000.
• 3.3. A K_m value for p-nitrophenylphosphate of 1.12mM has been found under optimal conditions.
• 4.4. The enzyme is selectively activated and stabilized by Mn²⁺.
• 5.5. It requires high salt concentrations for stability and maximum activity.
• 6.6. It displays an unusual restricted substrate specificity of 25 phosphate esters tested, only phosphotyrosine and casein were hydrolysed besides p-nitrophenylphosphate.

     

Differences in response patterns of labellar chemosensilla of the fleshfly Sarcophaga bullata

• 1.1. Electrophysiological responses to NaCl, sucrose, and a complex mixture containing NaCl, glucose, fructose, phenylalanine and valine were obtained from large, medium, and small hair sensilla on the proboscis of the fleshfly Sarcophaga bullata.
• 2.2. Responses from up to three cells in each sensillum were analysed and compared across the three types of sensilla.
• 3.3. We found qualitative differences in the patterns of responses from the different hair types.

     

Monoclonal antibodies prepared against heparin lyase I and their reactivity toward heparin lyase I,II and III

• 1.1. Six different monoclonal IgG mouse antibodies to heparin lyase I from Flavobacterium heparinum were prepared.
• 2.2. The monoclonal antibodies were used to detect heparin lyases I, II and III by dot-blotting immunoassay and by Western blotting.
• 3.3. Individual antibodies showed different reactivity toward the three heparin lyases.
• 4.4. The reactivity of two of the monoclonal antibodies was destroyed by exposing heparin lyases to sodium dodecyl sulfate.
• 5.5. The antibodies can be used to rapidly distinguish between the three heparin lyases.

     

Light-induced transient increase of the activity of topoisomerase I in plasmodia of Physarum polycephalum

• 1.1. Activity of topoisomerase I and incorporation of [³H]uridine and [¹⁴C]thymidine were monitored during light-induced sporulation of the slime mold Physarum polycephalun.
• 2.2. A 4-fold transient increase of topoisomerase I activity but not of [³H]uridine or [¹⁴C]thymidine incorporation was observed after 42 hr of illumination with 6 hr impulses.
• 3.3. The activity of topoisomerase I did not increase in the absence of light impulses. However, ca 5-fold increase of the activity was observed in dark when 100 μ M dibutyryl-cAMP was administered 12 hr before harvesting of plasmodia.
• 4.4. Fluorodeoxyuridine and cycloheximide administered 36 hr after starting of the illumination cancelled the increase of the activity of topoisomerase I.
• 5.5. After 7 days of the illumination, when fruiting bodies appeared, the activity of topoisomerase I dropped to about 15% of the initial value.

     

Structure of heparan sulfate from the fresh water mollusc Anomantidae sp: Sequencing of its disaccharide units

• 1.1. The disaccharide sequences of a heparan sulfate isolated from Anomantidae sp. was determined with the aid of heparitinase I, heparitinase II from Flavobacterium heparinum, mollusc β-glucuronidase and α-N-acetylglucosaminidase besides nitrous acid degradation and chemical analyses.
• 2.2. Like the mammalian heparan sulfates the mollusc heparan sulfate is composed of different oligosaccharide blocks of N-acetylated disaccharides, N-sulfated disaccharides and N,6-sulfated disaccharides and has in its nonreducing end the monosaccharide glucosamine 2,6-disulfate.
• 3.3. The oligosaccharides produced by heparitinase I degradation contain at their reducing ends a N-acetylated, 6-sulfated disaccharide.
• 4.4. These and other results lead to the conclusion that the general structure of the heparan sulfate is maintained through evolution.

     

An alkaline phosphatase from Thermus sp strain Rt41A

• 1.1. A thermostable orthophosphoric monoester phosphohydrolase (EC 3.1.3.1) from Thermus sp strain Rt41A has been purified 400-fold to give a specific activity of 25 U/mg at 60°C in IM diethanolamine (pH 11.1).
• 2.2. The enzyme has a M_r of 160,000 and is trimeric.
• 3.3. The half-life of the enzyme is 5 min at 85°C.
• 4.4. The enzyme has a wide specificity for a number of phosphate monoesters.
• 5.5. The H_m of the enzyme is pH dependent, so the pH optimum of the enzyme is affected by the substrate concentration.
• 6.6. The enzyme is inhibited 50% by 20 mM Ca²⁺ or Mg²⁺.
• 7.7. The K_i for phosphate, EDTA-di sodium salt and arsenate (in 1 M diethanolamine, pH 11.1) is approx 1.2, 1.6 and 4mM respectively.
• 8.8. Urea (200 mM) is not inhibitory.

     

Interference of benzo[a]pyrene with cytochrome P-450-mediated steroid metabolism in pyloric caeca microsomes of the sea star Asterias rubens L.

• 1.1. The effects of benzo[a]pyrene (BaP) on the metabolism of progesterone and pregnenolone, and the effects of steroids on BaP metabolism were examined in pyloric caeca microsomes of female Asterias rubens.
• 2.2. The patterns of metabolism of progesterone and pregnenolone in microsomes were similar to those found in previous studies for homogenates and tissue incubations of pyloric caeca.
• 3.3. BaP reduced the rate of hydroxylation of progesterone and pregnenolone, but had no effect on metabolite formation by non-cytochrome P-450-catalysed reactions.
• 4.4. Microsomal BaP hydroxylase activity was reduced by the presence of progesterone, but pregnenolone and testosterone had no such effect.
• 5.5. The reductions in steroid or BaP metabolism were progressive with increasing ratios of the concentration of the interfering compound to that of the assay substrate and were maximally 50% or less at ratios of × 100.
• 6.6. It is concluded that isoenzymic forms of cytochrome P-450 are present, with preferences towards either steroid or BaP metabolism. The implications of the results for the in vivo situation are discussed.

     

Characterization of glutathione S-transferases in a solitary bee,Megachile rotundata (Fab.) (hymenoptera: megachilidae) and inhibition by chalcones,flavone, quercetin and tridiphane-diol

• 1.1. The glutathione S-transferases of Megachile rotundata (Fab.) were characterized eletrophoretically and spectrophotometrically.
• 2.2. Differences were found between sexes with respect to number of isozymes and activity with age.
• 3.3. Inhibition patterns of chalcone, seven of its synthetic derivatives, flavone, quercetin, and tridiphanediol differed with respect to sex and substrate.
• 4.4. Comparisons are made with the honey bee, Apis mellifera L.

     

Co-localization of locustamyotropin- and pheromone biosynthesis activating neuropeptide-like immunoreactivity in the central nervous system of five insect species

• 1.1. Myotropin I of Locusta and Pheromone Biosynthesis Activating Neuropeptide (PBAN) of Heliothis share the same carboxyterminal pentapeptide FSPRL-amide.
• 2.2. Immunostaining revealed colocalization in cells and axons in the central nervous system, especially in the suboesophageal ganglion, of Locusta, Periplaneta, Leucophaea, Neobellieria (Sarcophaga) and Mamestra.
• 3.3. Following preabsorption with synthetic FSPRL-amide, the PBAN antiserum continued to immunostain cells in Mamestra and Neobellieria only. The preabsorbed Lom-MT I antibody did not yield any positive reaction.
• 4.4. Our results indicate that the functional epitope FXPRL-amide is widespread among insect orders. Its distribution in the nervous system seems to be rather similar in all investigated species.

     

Some properties of ATPase activity in the intact cells of yeast Saccharomycopsis fibuligera

• 1.1. The properties of ATPase activity were studied with the cells at the early stationary phase of Saccharomycopsis fibuligera.
• 2.2. Optimal pH for the activity was approximately 7.
• 3.3. The activity was stimulated by Mg²⁺.
• 4.4. The activity was inhibited by NaF, DCCD, oligomycin, NaN₃, NaVO₃, or PCMB but not inhibited by ouabain.

     

Haematology of the australian eastern quoll,Dasyurus viverrinus

• 1.1. A variety of haematological parameters were determined in adult Dasyurus viverrinus.
• 2.2. Haemoglobin and red cell counts were high with a very low mean cell volume.
• 3.3. Basophils are absent but the eosinophils contain small numbers of basophilic granules which may indicate a dual role for this cell.
• 4.4. “Ring Form” leucocytes are present.
• 5.5. Three types of red cell picture could be identified, some animals showing large numbers of spherocytes, spicule cells, and inclusion bodies.
• 6.6. These cells resemble those found in some inherited human haemolytic anaemias but there was no evidence of haemolysis in the animals.
• 7.7. An alkali resistant haemoglobin component is present.

     

Lipoxygenase of Thermoactinomyces vulgaris,purification and characterization of reaction products

• 1.1. A lipoxygenase preparation was obtained from Thermoactinomyces vulgaris and was purified by affinity chromatography on a linoleyl aminoethyl sepharose column.
• 2.2. Two active fractions were obtained.
• 3.3. The fraction obtained by elution with 100 mM borate buffer pH 9.0 was used in the subsequent work.
• 4.4. Th. vulgaris lipoxygenase oxidized linoleic acid into two products: 13-HPOD and 9-HPOD at a ratio of 44 to 56, respectively.
• 5.5. The identification and characterization of the isomers was done by HPLC, I.R. and mass spectrometry.
• 6.6. When arachidonic acid was used as substrate, 15-HPETE and 15-HETE were found to be the main enzymatic products.

     

Allozyme variation in a wild african elephant (Loxodonta africana) population from the Kruger National Park,South Africa

• 1.1. Blood, liver, heart, testis, skin, eye, muscle and kidney samples were obtained from elephants (Loxodonta africana) in the Kruger National Park during a culling programme in April 1992.
• 2.2. Gene products of 25 protein coding loci in L. africana were examined by horizontal starch-gel electrophoresis.
• 3.3. Eighteen protein coding loci (72%) displayed monomorphic gel banding patterns whereas only seven (28%) displayed polymorphic gel banding patterns.
• 4.4. Average heterozygosity values for adults, youngsters and the total population are respectively 0.058, 0.024 and 0.047.
• 5.5. Relative gene diversities within and between populations are 84% and 16% respectively.
• 6.6. Two population simulation programmes were utilized to predict the duration of the current variability present in this species, based on current genetic variation and gene transfer from one generation to the next.

     

Breast,hips, and buttocks revisited: Honest fatness for honest fitness

This paper comments on: Low, B. S., Alexander, R. D., and Noonan, K.M. Human hips, breast, and buttocks: Is fat deceptive? Ethology and Sociobiology 8: 249-247, 1987. In it I argue that:

• 1.1. Sexual selection has probably not been the most important selection pressure on
• 2.female human body shape.
• 3.2. Male humans in different cultures find different aspects of the female body attractive
• 4.and therefore are unlikely to have exerted consistent directional sexual selection on
• 5.the female body.
• 6.3. Breast size is not correlated with lactation success.
• 7.4. Visible hip width is not correlated with parturition success.
• 8.5. Women would lower their fitness if they tried to deceive men about their internal
• 9.pelvic dimensions.
• 10.6. There are many alternative hypothesis to explain the existence of fat onwomen's
• 11.breast, hips, and buttocks.

     

Different enzymes for laminarine digestion in Chondrostoma nasus (cyprinidae) and Oreochromis sp. (cichlidae)

• 1.1. The digestibility of laminarine in vitro differed significantly in a cyprinid and a cichlid fish under the same experimental conditions; in Chondrostoma nasus it never exceeded 30%, but amounted to up to 86% in Oreochromis sp.
• 2.2. It is assumed that different sets of laminarine-digesting enzymes are involved.
• 3.3. Both species posess an exo-laminarinase (α-d-1,3-glucane glucohydrolase), hydrolysing terminal glucose monomers until a β-d-1,6-linked branching site is reached in the laminarine molecule.
• 4.4. For the hydrolysis of the branching site the required β-1,6-glucohydrolase is lacking in Chondrostoma nasus. lio]5. A β-1,6-glucohydrolase in the intestine of Oreochromis sp. allows complete digestion of laminarine.

     

Responses of channel catfish (Ictalurus punctatus) swim-up fry to dietary calcium in soft and hard water

• 1.1. Responses of channel catfish (Ictalurus punctatus) swim-up fry to dietary calcium in soft (< 1 mg/1 as CaCO₃) and hard (> 100 mg/1 as CaCO₃) water were determined by feeding purified egg-white diets containing 0, 0.5, 1.0, or 2.0% calcium from CaCO₃ for 8 weeks.
• 2.2. Catfish fry fed the basal diet (0.03% Ca) in hard and soft water had lower whole-body ash and whole-body calcium concentrations but higher weight gain and survival than those fed calcium-supplemented diets.
• 3.3. Fry in soft water generally had lower whole-body ash, whole-body calcium, and survival, as well as a higher incidence of spinal deformities than fry in hard water.
• 4.4. Feeding higher levels of calcium to fry reared in soft water did not increase whole-body calcium levels or decrease spinal deformities to the levels observed for fry reared in hard water and fed supplemental calcium.
• 5.5. These data indicate that calcium derived solely from dietary or environmental sources was not sufficient for optimum health of channel catfish fry.

     

Organohalogen constituents of the acorn worm Ptychodera bahamensis

• 1.1. Twenty organohalogen compounds, primarily phenols, were detected in the volatile extracts of the acorn worm Ptychodera bahamensis.
• 2.2. Five chlorinated compounds, previously undescribed from acorn worms, were identified.
• 3.3. Enteropneusts can be significant contributors of halogenated organics to the marine environment.