Studies on the enzymatic activities related to varied pattern of diets in the air-breathing cat fish,clarias batrachus (Linn.)

1. Specific activity of amylase, cellulase, protease and lipase in the intestines of the air-breathing catfish, Clarias batrachus (Linn.) has been studied.
2. Excepting amylase and protease, the activity of lipase and cellulase showed practically no changes with change in the nutritional status of the diets.
3. pH optima of all enzymes were between 6.9 and 7.6
4. There is reason to believe from cellulase and high amylase activity in the intestine of the species that its culture operation could be done more economically by giving them a supplementary diet from indigeneously available raw material particularly from plant origin.

     

Alterations in proteases,protease inhibitors and ecdysone levels: a profile of stress in insects

• 1.1. A comparison of proteolytic and protease inhibitory activity, and ecdysteroid levels in body fluids was made between normal larvae of the flesh fly, Sarcophaga bullata, and those that had been water-stressed for two days.
• 2.2. The course of proteolytic activity in water stressed flies decreases 6 hr after beginning the experiment and remains low in comparison with control flies.
• 3.3. The course of protease inhibitors exhibits a mirror image pattern to proteases.
• 4.4. Ecdysteroid pattern shows two peaks in control animals: minor at 24 hr and major at pupariation, in experimental animals: at 1 hr, at 6 hr and at white pupal stage.

     

Intracellular proteolytic activity in developing myxospores of Myxococcus xanthus

1. Cell-free extracts from vegetative cells and developing myxospores of Myxococcus xanthus were found to contain similar amounts of proteolytic activity, approximately 80% of which was due to one or more neutral metal proteases.
2. Sixty per cent of the proteolytic activity was particulate.
3. The specific activity of the proteases was high throughout all stages of myxospore formation and displayed small increases in activity at two stages of development: (1) during cell shortening and (2) immediately following the conversion to spheres. The first peak in activity was apparent in assays conducted at pH 8 or 10 whereas the second peak was obvious only at pH 6.
4. A mutant which develops into myxospores only after a lag of approximately 7–8 h possessed levels of proteases similar to the wild type and displayed a peak in proteolytic activity after a delay of 7–8 h.
5. Low levels of serine protease activity were occasionally detected in both vegetative cells and myxospores; no sulfhydryl proteases were detectable in either cell type.
6. Extracellular proteases accumulated in the medium throughout myxospore development but differed from the intracellular proteases in pH optima and sensitivity to inhibitors.

     

Protease and Amylase in the digestive tract ofBarbus paludinosus

1. Protease and amylase activity in the digestive system ofBarbus paludinosus Peters (Pisces, Cyprinidae) has been investigated.
2. Chromatographic analysis showed seven amino acids to be present in both the anterior and posterior intestine. Only leucine, phenylalanine, valine, glycine and aspartic acid were positively identified.
3. In the anterior intestine chromatography revealed two sugars, but only one in the posterior intestine which was identified as glucose.
4. The pH of the intestinal fluid was found to be 5.8 and 7.8 for the fore and hind gut respectively, This correlates well with the enzyme pH optima found in in vitro experiments.
5. Protease and amylase activity was found throughout the digestive tract. Maximum proteolytic activity being present in the anterior intestine. Amylase activity is similar in both regions of the gut.
6. Correlation between the digestive enzymes and the fishes diet is briefly discussed.

     

Effects of a purine inhibitor,allopurinol, on urate metabolism in the german cockroach,Blattella germanica L. (Dictyoptera: Blattellidae)

• 1.1. Adult male and female cockroaches (Blattella germanica) were maintained on a positive nitrogen balance diet (66% protein) containing various levels of allopurinol (0–3%) to determine the effects of allopurinol on urate synthesis and storage.
• 2.2. Each insect was injected with [¹⁴C]hypoxanthine and after 1 week was analyzed for whole-body hypoxanthine, xanthine and urate radiolabel.
• 3.3. There was a general trend of decreased whole-body radiolabel retention, radiolabeled body urates and total-body urate content in both sexes with increasing amounts of dietary allopurinol.
• 4.4. Virgin female adults were allowed to feed on diets containing 0, 25 and 66% protein plus 0.1% allopurinol and were injected with [¹⁴C]xanthine.
• 5.5. After 1 week radiolabel content in the whole-body xanthine and urate pools was determined.
• 6.6. Females on the 0% protein diets contained less radiolabel in the whole-body and body urates than those on either 25 or 66% protein diets.

     

Digestive protease,lipase and amylase activities in stage i larvae of the american lobster,Homarus americanus

• 1.1. Digestive protease, lipase, and amylase of Stage I larvae of the American lobster Homarus americanus are characterized.
• 2.2. A sensitive method for detection of crustacean lipase was developed using an latroscan which combines thin-layer chromatography and flame ionization detection to quantify free fatty acids generated by lipase digestion.
• 3.3. pH optima of the three enzymes occurred at or near the pH of gastric fluid.
• 4.4. A time course study demonstrated slight increases in protease and amylase activities during the first larval stage, regardless of whether the lobsters were fed or not, whereas lipase activity was constant.

     

Seasonal variation in the biochemical composition of Mytilus viridis at Ratnagiri on the West Coast of India

1. The seasonal variation in the water, protein, fat and glycogen contents of the mussel, Mytilus viridis has been studied for the year March, 1974 to March, 1975.
2. The water level increased during the monsoon season and decreased in summer.
3. The level of protein, fat and glycogen showed correlation with the reproductive cycle of the mussel.
4. The protein level was high when the mussels were mature and dropped during the breeding period.
5. During sex change from male to female in May the protein level remained high whereas during sex change from female to male in October and November it was low.
6. The fat level was high in mature mussels and declined on spawning.
7. The glycogen level was at its peak in immature mussels and low in mature.

     

Ontogenic change of digestive enzymes in Penaeus monodon

• 1.1. Ontogenic changes of both proteases and carbohydrases of Penaeus monodon from different larva stages to adult were investigated.
• 2.2. Total protease activity was low during nauplius and zoea but peaked up in mysis. This was due to the activity increase of both trypsin and chymotrypsin.
• 3.3. The change of isozyme pattern of these two enzymes from different life stages of the shrimp was further determined by functional staining on an electrophoregram.
• 4.4. Activity of α-amylase increased after the post-larva stage, while that of chitinase and maltase showed a peak in zoea then gradually decreased to adult.
• 5.5. The ratio of α-amylase activity to protease coincided with the dietary change of the shrimp in different life stage.

     

Growth of a floating aquatic weed,Salvinia under standard conditions

1. Growth of the floating aquatic weed, Salvinia, in sterile culture was exponential for at least 2 weeks under standardized conditions.
2. Increase in light intensity or in CO₂ resulted in increases in growth rate, but did not extend the exponential period of growth.
3. This aquatic plant, like many others, discriminates against calcium relative to strontium.
4. In culture Salvinia exhibited luxury consumption of N and P.
5. Because of high C/N ratios, Salvinia may not be a favorable source of animal food, but might be useful in nutrient removal schemes.
6. In sterile culture, S. molesta produced fewer leaves than S. minima, but maintained a significant increase in leaf area and dry weight. This may be correlated with the ability of the first species to rapidly spread over tropical waterways.

     

Charkterisierung eines phagenähnlichen Partikels aus Zellen von Nitrobacter

1. Phage-like particles Nb₁ isolated from cells of Nitrobacter agilis were characterized after freeze etching and after treatment by fixation agents.
2. Ethanol-acetic acid fixed particles can be digested by the proteolytic enzyme papain.
3. Ethanol-acetic acid fixed particles show a loss in mass and volume after treatment with DNase. Under the same conditions RNase has no influence.
4. The chemical composition of the phage-like particle Nb₁ is discussed.

     

Proteolytic system in Babesia hylomysci

• 1.1. Babesia hylomysci has an aminopeptidase and an acid endoprotease
• 2.2. The amino-peptidase has properties very similar to the aminopeptidase in Plasmodium yoelii nigeriensis and P. chabaudi.
• 3.3. The acid endoprotease is specific towards haemoglobin and practically has no action on bovine serum albumin.
• 4.4. In mouse normal red blood cells we find an acid protease having physico-chemical properties similar to the enzyme present in B. hylomysci extracts.
• 5.5. The similarity of electrophoretic velocity between acid protease in B. hylomysci and non-infected red blood cells leads us to think that the acid protease of parasitic extracts comes from the host-cell.
• 6.6. The proteolytic system of Babesia and Plasmodium are similar.

     

Sulphhydryl protease inhibitors from pineapple plant stem

• 1.1. Pineapple stem extract, consisting of a mixture of the protease bromelain and sulphhydryl protease inhibitors, was fractionated by gel permeation chromatography.
• 2.2. Inhibitor-containing fractions were further resolved by ion exchange chromatography on DEAE-cellulose, giving 12 chromatographically distinct inhibitory fractions.
• 3.3. These 12 inhibitory fractions all show an inhibition specificity towards bromelain.
• 4.4. Reduction, S-carboxymethylation and refractionation of each of these inhibitory fractions gave, for each fraction, two separated peptides of ca 13 and 40 amino acids in length, respectively.
• 5.5. The amino acid compositions and the N-terminal sequences of these peptides show the inhibitors to be a closely homologous set. Both the constituent peptides of each fraction are microheterogeneous. Each DEAE-cellulose chromatogram peak contains a co-eluting set of iso-inhibitors.
• 6.6. Structural microvariations within these isoinhibitors have a minor influence on inhibitor activity towards bromelain.

     

Field and Experimental Studies on the Effects of a power station effluent on tubificidae (Oligochaeta,Annelida)

1. Higher numbers of sexually mature worms of L. hoffmeisteri were found in the River Trent downstream from Drakelow Power Stations than upstream.
2. The condenser effluent from the power stations not only increased the temperature of the river but also produced a considerable increase in the concentration of dissolved oxygen.
3. Experiments were therefore carried out on the effects of these two variables on the reproductive rate of the worms.
4. In these experiments it was found that: (a) L. hoffmeisteri increased its rate of egg production with increase in temperature up to about 25°C while T. tubifex maintained a fairly steady rate of egg production over a range of temperatures from 10–25°C. (b) L. hoffmeisteri maintained a fairly steady rate of egg and cocoon production over a wide range of oxygen concentrations above 2 ppm.
5. Therefore it seems likely that the difference between the numbers of sexually mature L. hoffmeisteri upstream and downstream from the power station were influenced more by the increased temperature, than the increased oxygen levels of the power station effluent, though under extreme conditions of deoxygenation, aeration of the river by the cooling towers at the power stations could increase the abundance of this species.

     

Diurnal variation in Sagar Lake,Sagar (India) I studies in the deep water area

1. A diurnal study of inland fresh water lake has been made with respect to physical and chemical properties and the plankton.
2. Chlorides have followed the total carbonates while dissolved oxygen and pH have shown no relation.
3. Microcystis has followed no definite pattern of diurnal movement.
4. All crustaceans, some of the rotifers andTrachelomonas perform considerable diurnal movement in the course of a twenty four hour period.

     

Seasonal variations in biochemical constituents of the clam,Paphia laterisulca

1. The total protein, fat and glycogen contents were estimated from the edible clam, P. laterisulca. Seasonal variations in these constituents along with the water content were studied.
2. The gonad index in P. laterisulca was found to increase during the ripe condition and in winter (December–January) and decrease on spawning.
3. A relatively high water content was obtained during monsoon (June to September). This might be due to the loss of salts and gain of water in low salinities.
4. Protein content varied with the reproductive cycle of the clam. The level reached its peak in the mature stage and declined on spawning. Immature clams showed less protein content than gravid ones.
5. Lipid content started to increase as the gametogenesis commenced, reached its peak in fully mature condition (August) and sharply declined due to the shedding of gametes during spawning.
6. Glycogen content was high during the period of active gameto-genesis (May–June). A sharp decrease took place when the clams were fully ripe (July). The glycogen might have been utilized in the formation of active ripe gametes.
7. After starvation for twelve days, total protein and fat contents remained constant, while glycogen content decreased by 66.82%. The water content increased by 4.67%.
8. Seasonal variation in the organic constituents are discussed in relation to the reproductive cycle of the clam.

     

Hide protease in stored product mites (Astigmata:acaridae)

• 1.1. Hide protease activity was detected in 6 species of stored product mites; Acarus siro Linnaeus, Glycyphagus destructor (Schrank), Glycyphagus domesticus (De Geer), Rhizoglyphus callae (Oudemans), Rhizoglyphus robini Claparede and Tyrophagus longior (Gervais).
• 2.2. Significant differences in specific activity were found between, but not within, species.
• 3.3. A. siro L. and Glycyphagus spp. show relatively high activity, Rhizoglyphus spp. and T. longior (Gervais) relatively low activity.
• 4.4. Possible explanations for these results are discussed.

     

A possible cause of heterogeneity of mammalian apurinic/apyrimidinic endonuclease

• 1.1. Mammalian major apurinic/apyrimidinic (AP) endonuclease, APEX nuclease (M_r 35.4 kDa) was purified from HeLa cells. A hybrid protein (M_r 36.4 kDa), which was expressed in BW2001 strain cells of E. coli, comprising human APEX nuclease headed by 10 additional amino acids was also purified.
• 2.2. The purified preparations were frequently associated with 31-, 33- and 35-kDa peptides having AP endonuclease activity.
• 3.3. The 33- and 35-kDa peptides were suggested to be formed from the hybrid protein or APEX nuclease during their purification processes by proteolytic cleavage with subtilisin-like protease. The 31-kDa peptide was thought to be produced by chemical cleavage of the aspartyl-prolyl bond of APEX nuclease.
• 4.4. The results support the notion that some of AP endonuclease heterogeneity based on the molecular weight difference are caused by proteolytic (and chemical) cleavage of a species of AP endonucleases during the extraction and purification.

     

Control of mucin molecular forms expression by salivary protease: Differences with caries

• 1.1. A protease activity capable of degradation of the high mol. wt salivary mucus glycoprotein to a low mol. wt glycoprotein form was identified in human submandibular gland secretion.
• 2.2. The protease exhibited optimum activity at pH 7.0–7.4, and gave on SDS-PAGE under reducing conditions two major protein bands of 48 and 53 kDa. The enzyme showed susceptibility to PMSF, α₁antitrypsin, and egg white and soybean inhibitors, a characteristic typical to serine proteases.
• 3.3. The activity of the protease towards the high mol. wt mucus glycoprotein was found to be 3.8-fold higher in submandibular gland secretion of caries-resistant individuals than that of caries-susceptible. Furthermore, the enzyme from both groups displayed greater activity against the mucus glycoprotein of caries-resistant subjects.
• 4.4. Since the low mol. wt salivary mucus glycoprotein form is more efficient in bacterial clearance than the high mol. wt mucin, the enhanced expression of this indigenous salivary protease activity towards mucin may be the determining factor in the resistance to caries.

     

Growth and haematological response of sturgeon hybrids Russian sturgeon (Acipenser guldenstadti brandt) × beluga (Huso huso L.) to protein and lipid contents in the diet

• 1.1. Fingerlings of intergenious hybrid Russian sturgeon (Acipenser guldenstadti) × beluga (Huso huso) weighing 22 g reared in water with salinity 18 ppt were fed nine diets differing in protein and fat content.
• 2.2. The increase of dietary protein content (from 45 to 52%) improved the fingerlings growth rate, food and protein conversion efficiencies. No effect of further protein content increase to 60% was observed.
• 3.3. The increase of dietary fat content from 10 to 20% positively influenced all growth results.
• 4.4. The muscular lipid content increased following the increase in dietary fat due to accumulation of triacylglycerols.
• 5.5. Distinctive leucopenia in neutrophils and leucophilia in lymphocytes following dietary protein and fat content increase were observed.
• 6.6. It was concluded that within the analysed range of values the increase of dietary protein and lipid content improved the physiological status of sturgeon hybrid fingerlings.

     

Oxygen consumption and respiratory behaviour of three Nile fishes

1. The respiratory behaviour and patterns of oxygen consumption of three Nile species have been investigated.
2. Tilapia nilotica showed a typical pattern of oxygen consumption with an ambient region, adaptive plateau and lethal region (Fig. 2).
3. Specimens of Polypterus senegalus and Clarias lazera (body weights 20–30 and 30–45 g respectively) showed patterns of consumption comparable to that of Tilapia (Fig. 3a and 4a). In larger specimens of the two species the adaptive plateau was either insignificant or completely absent.
4. Specimens of Polypterus and Clarias (20–30 g and 30–45 g respectively) could survive in waters saturated with oxygen (7.4 mg/l) but their tolerance to lower oxygen concentrations was limited. Larger specimens of Polypterus and Clarias failed to survive in oxygen saturated waters.
5. The tolerance of Tilapia nilotica to extremely low oxygen concentration is an adaptation of a tropical and completely aquatic species. Polypterus and Clarias resort to their compensatory mechanisms only when the aquatic respiratory surface fails to satisfy their oxygen requirements.