Isolation of fungi from bats of the Amazon basin

A total of 2,886 bats captured in the Amazon Basin of Brazil were processed for the isolation of fungi. From the livers, spleens, and lungs of 155 bats (5.4%), 186 fungal isolates of the genera Candida (123 isolates), Trichosporon (26 isolates), Torulopsis (25 isolates), Kluyveromyces (11 isolates), and Geotrichum (1 isolate) were recovered. Seven known pathogenic species were present: Candida parapsilosis, C. guilliermondii, C. albicans, C. stellatoidea, C. pseudotropicalis, Trichosporon beigelii, and Torulopsis glabrata. Twenty-three culture-positive bats showed identical fungal colonization in multiple organs or mixed colonization in a single organ. The fungal isolation rates for individual bat species varied from 1 fungus per 87 bats to 3 fungi per 13 bats, and the mycoflora diversity for members of an individual fungus-bearing bat species varied from 16 fungi per 40 bats to 7 fungi per 6 bats. Of the 38 fungal species isolated, 36 had not been previously described as in vivo bat isolates. Of the 27 culture-positive bat species, 21 had not been previously described as mammalian hosts for medically or nonmedically important fungi.     

Beneficial effects of n-hexane bark extract of Onosma echioides L. on diabetic peripheral neuropathy

Onosma echioides Linn (Boraginaceae) is the most frequently used curative herb widely used for kidney obstruction, sciatic pain, and gout. The present study was designed to investigate the therapeutic effects of n-hexane bark extract of O. echioides (OE) L. root in vivo against Streptozotocin-induced diabetic neuropathy in SD rats. For in vivo activity, the experiment was categorized into five different groups (n = 5). Group-I was considered as nondiabetic/normal control (NC) treated with 0.5% carboxymethyl cellulose (CMC), Group II as diabetic control, Group-III, IV, and V served as diabetic treated with OE 50, OE 100, and pregabalin at a dose of 50, 100, and 10 mg/kg body weight, orally, respectively. Body weight, blood glucose, oral glucose tolerance test, behavioral studies (motor coordination test, thermal hyperalgesia, cold allodynia, locomotor activity, oxidative biomarkers (thio barbituric acid reactive substances [TBARS], superoxide dismutase [SOD], glutathione [GSH], and catalase), and histopathology of the sciatic nerve were performed. Treatment with OE showed a dose-dependent increase in neuroprotective activity by improving the myelination and decreasing the axonal swelling of nerve fibers. The verdicts of behavioral activities showed a remarkable effect on animals after the treatment of extract and standard drug pregabalin. In conclusion, our findings supported the traditional application of OE and explored its importance in the management of diabetic neuropathy. Additional clinical experiments may provide novel therapeutic drugs for diabetes and its complications.     

Zonal variability and seasonal changes of the content of glycogen and glucose in the Mytilus mantle

Glycogen and free-glucose content in the ventral, central and dorsal parts, as well as glucose-6-phosphate phosphatase activity in mantle of Mytilus galloprovincialis Lmk. were examined. The glycogen content of mantle did not manifest asymmetrical distribution among the three parts. In the period studied, the typical glycogen content profile variation was found, being maximum in July. The tissue free-glucose content was similar in each part, and the obtained seasonal variation profile was opposite to the glycogen content, reaching the minimum in July. For every part of mantle, free-glucose/glycogen ratio showed similar monthly profiles. In each part the 50% point was found in July. Glucose-6-phosphate phosphatase activity was not found in the mantle tissue.     

Biosynthesis of platelet-activating factor in glandular gastric mucosa. Evidence for the involvement of the ''de novo'' pathway and modulation by fatty acids.

The biosynthesis of platelet-activating factor (PAF), a phospholipid autocoid with potent ulcerogenic properties that is produced in secretory exocrine glands by physiological secretagogues, was assessed in microsomal preparations of glandular gastric mucosa. For this purpose, 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine (lyso-PAF):acetyl-CoA acetyltransferase (EC 2.3.1.67); the enzymes of the 'de novo' pathway: 1-O-alkyl-2-lyso-sn-glycero-3-phosphate (alkyl-lyso-GP):acetyl-CoA acetyltransferase and 1-O-alkyl-2-acetyl-sn-glycerol (alkylacetyl-G):CDP-choline cholinephosphotransferase (EC 2.7.8.16); and some enzymes involved in the catabolism of PAF and lyso-PAF were assayed. Only the enzymes of the 'de novo' pathway and small amounts of PAF acetylhydrolase, phospholipase A2 and a lysophospholipase D acting on either lipids could be detected in the gastric preparations, whereas lyso-PAF:acetyl-CoA acetyltransferase activity was undetectable. The specific activity of alkyl-lyso-GP:acetyl-CoA acetyltransferase in the gastric mucosa was about one-tenth of that found in spleen microsomes and its apparent Km for acetyl-CoA was 454 microM compared with 277 microM in spleen microsomes. Glandular mucosa homogenates contained preformed PAF at a concentration of 2.7 +/- 0.7 ng equivalents of PAF (hexadecyl)/mg of protein. When gastric microsomes were incubated with micromolar concentrations of fatty acids (arachidonic, palmitic and oleic) prior to the assay of dithiothreitol (DTT)-insensitive cholinephosphotransferase, a dose-dependent reduction in the formation of PAF was observed, arachidonic acid being the most potent inhibitor, followed by linoleic acid (only tested on spleen microsomes) and oleic acid. By contrast, 1,2-diolein and phosphatidylcholine (dipalmitoyl) showed no or little effect. These results indicate that glandular gastric mucosa can produce PAF through the 'de novo' pathway, and that fatty acids, especially unsaturated, can reduce that synthesis by modulating the expression of DTT-insensitive cholinephosphotransferase.     

Modulation of acetyl-CoA:1-alkyl-2-lyso-sn-glycero-3-phosphocholine (lyso-PAF) acetyltransferase in human polymorphonuclears. The role of cyclic AMP-dependent and phospholipid sensitive, calcium-dependent protein kinases

In order to characterize the mechanism of activation of the enzyme 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine:acetyl-CoA acetyltransferase (EC 2.3.1.67) which is the limiting step in the regulation of the synthesis of the potent inflammatory mediator 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine; homogenates from human polymorphonuclear leukocytes were incubated in the presence of the catalytic subunit of cyclic AMP-dependent protein kinase and in the presence of a partially purified phospholipid sensitive, calcium-dependent protein kinase (PrKC). The first kinase was found to enhance up to 3-fold acetyltransferase activity in a dose- and time-dependent manner. In homogenates from PMN previously stimulated with complement-coated zymosan particles, the decay of acetyltransferase activity was partially prevented by the addition of soybean trypsin inhibitor and almost completely inhibited when the homogenates were supplemented with inhibitors of alkaline phosphatase such as 50 mM KF and 100 microM paranitrophenylphosphate. Under these conditions it was possible to initiate the decay of acetyltransferase activity by adding an excess of alkaline phosphatase. Preincubation of PMN with 12-O-tetradecanoylphorbol-13-acetate previous or simultaneously to the addition of ionophore A23187 reduced the increase in acetyltransferase produced by ionophore A23187, whereas the generation of superoxide anions was enhanced. Addition of partially purified PrKC to homogenates from ionophore A23187-stimulated PMN, reduced acetyltransferase activity by 63%, whereas only a 16% inhibition was observed on homogenates from resting PMN. These data indicate the modulation of acetyltransferase activity in human polymorphonuclear leukocytes by a phosphorylation-dephosphorylation mechanism linked to cyclic AMP-dependent protein kinase. Phospholipid sensitive, calcium-dependent protein kinase seems not to be involved in the mechanism of activation, but, most probably, in the generation of negative activation signals.     

Plasma and liver selenium levels in the rat during supplementation with 0.5, 2, 6, and 15 ppm selenium in drinking water

Plasma and liver selenium of Wistar rats were determined after 1, 3, and 6 mo supplementation with 0.5, 2, 6, or 15 ppm selenium as sodium selenite in drinking water. Plasma selenium was not different from control values at additional intake of 0.5 ppm but increased above usual levels at higher intakes. A highly significant correlation was observed between the total quantity of selenium ingested and plasma selenium after 1 mo treatment (r=0.99,p<0.01), but was less pronounced after 3 and 6 mo (0.94,p<0.05, and 0.78,p<0.05, respectively). The decrease in plasma selenium with time of treatment was more pronounced at higher intakes. There was also a highly significant correlation between total selenium intake and liver selenium concentration (r=0.99,p<0.01) after 1 mo of treatment, but this time liver selenium did not change with time, and the correlation remained highly significant throughout the investigation. Liver selenium therefore appears as a more sensitive and more representative measure of selenium intake than plasma selenium. Most supplements did not affect body weight and survival of animals, except when the diet was supplemented with 15 ppm for 6 mo; however, alterations in biochemical parameters concerning lipid status and hepatic function were observed at levels above 2.0 ppm.     

Histo-cytological study of the liver of the cabrilla sea bass, Serranus cabrilla (Teleostei, Serranidae), an available model for marine fish experimental studies

Livers of juvenile cabrilla sea basses ( Serranus cabrilla ) were subjected to light and electron transmission microscopy following different periods of maintenance in an aquarium. Since this fish is easy to feed in captivity and the hepatic structure was found to be comparable at the four periods tested (0, 5, 10 and 20 days), both at the histological and ultrastructural level, the liver of S. cabrilla could be an available model for marine contamination experimental studies. As in other fish species, it is not possible to distinguish the portal lobules and the triads. The Melano-Macrophage Centres contain tipofuscins, ceroids and haemosiderin, but they do not contain any melanin. The hepatocytes are arranged in cords (two cells thick), and, at the ultrastructural level, they show numerous microvilli in the perisinusoidal and canalicular areas. The hyaloplasm includes a considerable amount of glycogen and some lipid droplets are occasionally observed. Mitochondria, rough endoplasmic reticulum and the Golgi apparatus are relatively scarce.     

The effect of light levels on daily patterns of chlorophyll fluorescence and organic acid accumulation in the tropical CAM treeClusia hilariana

Sandy plains are characteristic of the coastal region of Brazil. We investigated the diel patterns of changes in organic acid levels, leaf conductance and chlorophylla fluorescence for sun-exposed and shaded plants ofClusia hilariana, one of the dominant woody species in the sandy coastal plains of northern Rio de Janeiro state. Both exposed and shaded plants showed a typical CAM pattern with considerable diel oscillations in organic acid levels. The degradation of both malic and citric acids during the midday stomatal closure period could lead to potential CO₂ fixation rates of 28 mol m^-2 s^-1 in exposed leaves. Moreover, exposed leaves exhibited large increases in total non-photochemical quenching (q_N) accompanied by a substantial decrease in effective quantum yield during the course of the day. However, these potential high rates of CO₂ fixation and the increases inqn of exposed plants were not enough to maintain the primary electron acceptor of photosystem II (q_A) in a low reduction state, similar to that of shaded plants. As a result, there was a moderate increase in the reduction state of q_A throughout the day. Most of the decline in photochemical efficiency of exposed leaves ofC. hilariana was reversible, as evidenced by the high levels of pre-dawn potential quantum yields (F_v/F_m) and their rapid recovery after sunset. However, the depletion of the organic acid pool in the afternoon resulted in an accentuated subsequent drop in F_v/F_m, suggesting that prolonged periods of water stress accompanied by high irradiance levels may expose plants ofC. hilariana in unprotected habitats to the danger of photoinhibition.     

High cell density reactor for the production ofLactobacillus plantarum

Summary The production of a flocculent strain ofLactobacillus plantarum was performed in a high cell density reactor: a fluidized bed reactor (FBR) with a settler and an external cell recirculation. Two variables were assessed, the recirculation rate (R) and the dilution rate (D). The effect of the latter is much more important than the effect of the former in ensuring a quick start up in the flocculation process. The cell volumetric productivities obtained with this system increase directly with dilution rate and recirculation rate. The values of cell volumetric productivities obtained are considerably higher than those obtained in continuous stirred tank reactors (CSTR) and much higher than in batch reactors.     

Muscarinic Acetylcholine Receptor Enhances Phosphatidylcholine Hydrolysis via Phospholipase D in Bovine Chromaffin Cells in Culture

Although it is well-established that inositol-containing lipids serve as precursors of intracellular second messenger molecules in chromaffin cells, we describe some findings that show the formation of diacylglycerol from phosphatidylcholine in response to agonist-mediated stimulation. Stimulation of chromaffin cells by acetylcholine produced a high turnover of phosphatidylcholine, as suggested by the release of [3H]choline derived from [3H]-phosphatidylcholine in experiments performed with [3H]choline chloride-prelabeled cells. An enhanced breakdown of phosphatidylcholine was also inferred from the finding of an increased formation of [3H]diacylglycerol in chromaffin cells prelabeled with [3H]glycerol. The diacylglycerol mass that accumulated after stimulation showed a distinct temporal course and seemed to exceed the mass that has been reported to be derived from phosphatidylinositol. In keeping with the purported origin from phosphatidylcholine, diacylglycerol showed a high content in [3H]oleate molecular species. Phospholipase D activity measurements and experiments performed in the presence of propranolol (an inhibitor of phosphatidic acid:phosphohydrolase) suggested that phosphatidylcholine is hydrolyzed by a phospholipase D activity, producing phosphatidic acid, which is subsequently degraded to diacylglycerol, rather than by a phospholipase C. Incubation of chromaffin cells in the presence of atropine before addition of acetylcholine showed complete inhibition of the increased formation of [3H]-diacylglycerol, whereas d-tubocurarine failed to do so. Taken together, these results suggest that acetylcholine activates phosphatidylcholine breakdown and diacylglycerol formation in chromaffin cells via a muscarinic-type receptor.