Production and characterization of alpha-amylase from Rhizopus sp

A strain of Rhizopus sp. screened among more than 800 filamentous fungi showed great ability to produce a thermostable alpha-amylase by solid state fermentation. The best production was obtained with a bran moisture content of 40% when the enzyme activity reached 60 EU/g. of medium. During the purification procedures, a column of DEAE-Sephadex A-50 separated the enzyme in two fractions and the larger (85% of the total activity) showed optimum pH in a range from 4.0 to 5.6. Optimum temperature was found at 60-65 degrees C and in this range no loss of activity was observed after 60 min. of treatment in pH 5,0. Its K-m and V-m are, respectively, of 5.0 mg/ml of starch and 10,01 uMol of reducing sugar/min./mg. of protein. Its molecular weight was calculated in 64.000 by gel filtration in Sephadex G-200. The dextrinization power of the enzyme was observed preferentialy on substrates compound by chains with higher ramifications, that is: amylopectin > starch > amylose. Other aspects of the enzyme pattern action are also discussed.

Crotoxin-induced behavioral effects in rats

Crotoxin is the major component of Crotalus durissus terrificus venom. In view of the presence of high-affinity specific binding sites for crotoxin in the brain, the objective of this work was to investigate whether crotoxin induces behavioral effects in the open-field and hole-board tests. Adult male Wistar rats (180-220 g) treated with crotoxin, 100, 250 and 500 mu g/kg, ip, administered 2 h before the test, presented statistically significant behavioral alterations (ANOVA for one-way classification complemented with Dunnet test, P<0.05). In the open-field test, 250 and 500 mu g/kg of crotoxin increased freezing (from 3.22 sec to 10.75 sec and 11.2 sec) and grooming (from 13.44 sec to 22.75 sec and 21.22 sec) and decreased ambulation (from 64.8 to 39.38 and 45.8). The dose of 500 mu g/kg also decreased rearing (from 24.9 to 17.5). In the hole-board test, 500 mu g/kg of crotoxin decreased head-dip count (from 6.33 to 4.00). All the crotoxin-induced behavioral effects were antagonized by an anxiolytic dose of diazepam (1.5 mg/kg, ip, 30 min before the tests). These results show that crotoxin reduced open-field activity and exploratory behavior as well. We suggest that these effects express an increased emotional state induced by this toxin.

Central interaction between atrial natriuretic peptide and angiotensin II in the control of sodium intake and excretion in female rats

We investigated the effects of estrogen on sodium intake and excretion induced by angiotensin II (ANG II), atrial natriuretic peptide (ANP) or ANG II plus ANP injected into the median preoptic nucleus (MnPO). Female Holtzman rats weighing 250-300 g were used. Sodium ingestion and excretion 120 min after the injection of 0.5 mu l of 0.15 M NaCl into the MnPO were 0.3 +/- 0.1 ml (N = 12) and 29 +/- 7 mu Eq in intact rats, 0.5 +/- 0.2 ml (N = 10) and 27 +/- 6 mu Eq in ovariectomized rats, and 0.2 +/- 0.08 (N = 11) and 38 +/- 8 mu Eq in estrogen-treated ovariectomized (50 mu g/day for 21 days) rats, respectively. ANG II (21 mu M) injection in intact, ovariectomized, and estrogen-treated ovariectomized rats increased sodium intake (3.8 +/- 0.4, 1.8 +/- 0.3 and 1.2 +/- 0.2 ml/120 min, respectively) (N = 11) and increased sodium excretion (166 +/- 18, 82 +/- 22 and 86 +/- 12 mu Eq/120 min, respectively) (N = 11). ANP (65 mu M) injection in intact (N = 11), ovariectomized(N = 10)and estrogen-treated ovariectomized (N = 10) rats increased sodium intake (1.4 +/- 0.2, 1.8 +/- 0.3, and 1.7 +/- 0.3 ml/120 min, respectively) and sodium excretion (178 +/- 19, 187 +/- 9, and 232 +/- 29 mu Eq/120 min, respectively). Concomitant injection of ANG II and ANP into the MnPO of intact (N = 12), ovariectomized (N = 10) and estrogentreated ovariectomized (N = 10) rats caused smaller effects than those produced by each peptide given alone: 1.3 +/- 0.2, 0.9 +/- 0.2 and 0.3 +/- 0.1 ml/120 min for sodium intake, respectively, and 86 +/- 9, 58 +/- 7, and 22 +/- 4 mu Eq/120 min for sodium excretion, respectively. Taken together, these results demonstrate that there is an antagonistic interaction of ANP and ANG II on sodium intake and excretion, and that reproductive hormones affect this interaction.

Use of cationic surfactant-xylenol orange indicator in metals complexometry by back-titration with EDTA.

The interaction of the xilenol orange and commercial disinfectant containing itself cationic-surfactant allowed the use indicator up to pH 11 by back-titration with EDTA, and the determination of total or partial concentration of metallic ions samples using the same indicator at the highest pH range.

Influence of silver additions on the Cu-13 wt pct Al alloy hardness.

The influence of silver additions on the Cu-13 wt. pot. Al alloy hardness was studied for additions in the range 0 to 16 wt. pot Ag. The results indicated a pronounced hardness increase with the silver content and an influence of the quenching temperature. Data obtained from scanning electron microscopy indicated that the formation of silver-rich precipitates, wich change with the quenching temperature, seems to produce the changes on alloys hardness.

Isolation of Campylobacter jejuni from viscera and bile secretion of broiler chickens with diarrhea

Since chickens are important reservoirs of Campylobacter jejuni and their meat is the most frequent route of transmission for human campylobacteriosis, the purpouse of the present study was to investigate the presence of Campylobacter in viscera of chickens with diarrhea, evaluating the frequency of isolation of this microorganism from organs considered to be preferential for its isolation. A total of 107 visceral samples from chickens with diarrhea from different farms in the Ribeirao Preto region, SP, were examined for the presence of Campylobacter jejuni. The material consisted of 73 livers and 34 spleens, plus 29 bile secretion samples. The frequency of Campylobacter jejuni isolation was 54.79% for the liver samples, 35,29% for the spleens and 6,89% for the bile secretion samples. The data suggest that, under the conditions of the present study, the liver may be the organ of choice for the isolation of Campylobacter in the presence of diarrhea and liver involvement in chickens.

Stem anatomy of Lycopersicon esculentum Mill. treated with different plant growth regulators

The effects of plant growth regulators GA(3) 50 mg. L-1, NAA 100 mg. L-1, CCC 1500 mg.L-1 and SADH 3000 mg.L-1 on stem anatomy of Lycopersicon esculentum Mill cv. Angela Gigante were studied. Two sets of experiments were carried out in greenhouse during two separte periods. Anatomical studies,revealed that growth promoters induced increased xylem thickness and increased the number of tracheary elements while the growth retardants decreased xylem thickness and induced fiber formation.

HIGH DIETARY CARBOHYDRATE AND PANCREATIC LESION

The ability of high dietary carbohydrate to induce acute pancreatitis was investigated in groups of 16,2 1-day and 15-month old rats fed different carbohydrate diets for 30 days. Significantly increased levels of serum amylase (2-fold), phospholipids (50%),phosphorus (2-fold), and lipoperoxides (8-fold) were observed in 15-month old rats fed a high-carbohydrate diet, compared to rats fed a diet with normal carbohydrate levels, indicating peroxidation of membrane lipids which caused final cell death and pancreatic lesion. Serum Cu-Zn superoxide dismutase activity was not altered. Daily administration of bovine Cu-Zn superoxide dismutase conjugated with polyediylene glycol prevented the serum level alterations and pancreatic lesions, indicating that the superoxide radical has a role in dietary carbohydrate-induced acute pancreatitis. No biochemical changes were observed in rats in which treatment was initiated on the 21st day of life indicating that this is an age-related lesion.