Inhibition of carotenoid synthesis in Myxococcus fulvus (Myxobacterales)

1. The inhibitory effects of CPTA, nicotine, DPA, and San 6706 on carotenogenesis in Myxococcus fulvus were investigated.
2. The effects of CPTA, D-nicotine, and L-nicotine were very similar. The action of the drugs wasadditive. The cyclization was inhibited at low doses, the introduction of the hydroxyl group at C-1′ at higher doses. Lycopene accumulated at high drug concentration. The mode of action of the inhibitors is discussed.
3. In a carotenoid mutant of M. fulvus a stimulation of the “7,8-dehydrogenase” by CPTA was observed.
4. The specific carotenoid content of bacteria was increased by DPA due to an enhanced formation of phytoene. At low doses of DPA small amounts of an intermediate carotenoid glucoside ester, a 7,8-dihydro derivative, were detected.
5. DPA was taken up by the plasma membrane. Quantitative removal of DPA by washing was not possible.
6. San 6706 specifically and reversibly blocked the desaturation of phytoene.

     

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.

     

Chemolithotrophic growth and regulation of hydrogenase formation in the coryneform hydrogen bacterium strain 11/x

1. The present paper deals with the chemolithotrophic growth of a Gram-positive hydrogen bacterium strain 11/x which shows the characteristic features of some coryneform bacteria.
2. Like other hydrogen bacteria, the strain 11/x is a facultative chemolithotroph and grows on many organic substrates faster than in a mineral medium under an atmosphere of knallgas+CO₂. Fully induced, autotrophically grown cells, subcultured mixotrophically on fructose show additive growth.
3. Cell-free extracts of autotrophically grown cells are able to reduce methylene blue, dichlorophenolindophenol, phenazine methosulphate, menadione, and FMN with hydrogen. Conditions for direct NAD(P) reduction could not be found.
4. Hydrogenase is formed under autotrophic as well as mixotrophic conditions. In the latter case the rate of hydrogenase formation is diminished depending on the organic substrate. Heterotrophically grown cells do not have any detectable hydrogenase activity. For the induction of hydrogenase in those cells a nitrogen source is a prerequisite.
5. The formation of ribulose-1,5-diphosphate carboxylase and phosphoribulokinase seems to be regulated in a way similar to that of hydrogenase: the enzymes could only be detected in autotrophically and mixotrophically grown cells but not in those grown heterotrophically.

     

Aerobic and anaerobic growth of Paracoccus denitrificans on methanol

1. The dye-linked methanol dehydrogenase from Paracoccus denitrificans grown aerobically on methanol has been purified and its properties compared with similar enzymes from other bacteria. It was shown to be specific and to have high affinity for primary alcohols and formaldehyde as substrate, ammonia was the best activator and the enzyme could be linked to reduction of phenazine methosulphate.
2. Paracoccus denitrificans could be grown anaerobically on methanol, using nitrate or nitrite as electron acceptor. The methanol dehydrogenase synthesized under these conditions could not be differentiated from the aerobically-synthesized enzyme.
3. Activities of methanol dehydrogenase, formaldehyde dehydrogenase, formate dehydrogenase, nitrate reductase and nitrite reductase were measured under aerobic and anaerobic growth conditions.
4. Difference spectra of reduced and oxidized cytochromes in membrane and supernatant fractions of methanol-grown P. denitrificans were measured.
5. From the results of the spectral and enzymatic analyses it has been suggested that anaerobic growth on methanol/nitrate is made possible by reduction of nitrate to nitrite using electrons derived from the pyridine nucleotide-linked dehydrogenations of formaldehyde and formate, the nitrite so produced then functioning as electron acceptor for methanol dehydrogenase via cytochrome c and nitrite reductase.

     

Composition chimique elementaire des populations naturelles de Sphaeroma hookeri (Crustace: Isopode Flabellifere). Aspect spatio-temporel

1. Elemental chemical composition of Sphaeroma hookeri Leach of different natural populations from Camargue (Rhône delta) and from the Bassin de Berre (near Marseilles), was studied on samples taken the same day in different populations and on samples collected at different seasons in the same population.
2. Individual analyses of carbon, hydrogen and nitrogen were performed with a Perkin Elmer elemental analyzer. Total inorganic content was obtained for each specimen by weighing the residue after the output of the analyzer.
3. Relative growth in ash, carbon, hydrogen and nitrogen content of the different populations samples was compared by means of Reeve's statistical method.
4. Chemical allometry lines of each population are given. Variability of growth coefficients or mean values in a given population appears from several samples taken in the course of the year.
5. The differences in slope and position have been tested and their significance stated.
6. Growth coefficients of ash, carbon, hydrogen and nitrogen contents show a certain variability among the different populations. But these differences are not always significant owing to the dispersion of the data, a result of the wide individual variation within a population.
7. Much greater significant differences appear from relative positions of the growth lines, and these seem to be due to some ecological factors, among which, for instance, nutriment can lead to a large difference in carbon content.
8. Within a given population no significant difference appears in the growth coefficients of ash, carbon, hydrogen or nitrogen content and therefore the obtained values characterize each population.

     

Growth of Nitrobacter in the presence of organic matter

1. Culture filtrates of heterotrophic bacteria were tested for their stimulatory effect on nitrification of three strains of Nitrobacter.
2. Yeast extract-peptone solution, in which Pseudomonas fluorescens had grown, after removal of the cells was added to autotrophically growing cultures of Nitrobacter agilis; it caused a stimulated nitrite oxidation and growth of Nitrobacter agilis.
3. The degree of stimulation depended on: a) the proportion of the culture filtrate to the autotrophic medium; b) the composition of the complex medium in which Pseudomonas fluorescens had been grown; c) the time the heterotrophic bacterium had been grown in the complex medium.
4. The stimulatory effect was highest with Nitrobacter agilis, less with Nitrobacter winogradskyi and negligible with Nitrobacter K ₄.
5. It was possible to adapt nitrifying cells of Nitrobacter agilis to higher concentrations of yeast extract and peptone. After the nitrite had been completely oxidized the cell-N still increased up to 30% before growth stopped.

     

Metabolic products of microorganisms

1. The total nitrogen content of spores of Penicillium notatum increased during swelling and reached a maximum before germ-tubes were formed. It subsequently decreased during germ-tube formation until a constant value in hyphae was reached.
2. An increase in the protein content of the spores was found during swelling, followed by a decrease when germ-tubes were formed. After germination, the protein content increased again to a constant level in hyphae.
3. The content of total lipids steadily decreased during swelling of spores. It reached a minimum value in germinating spores, followed by a net accumulation during hyphal growth. Similar changes occurred in free lipids, phospholipids and the acetone-soluble lipids but not in bound lipids.
4. After an initial decrease during swelling, no further change took place in the neutral carbohydrates content of the spores at the time of germ-tube formation. An accumulation of neutral carbohydrates occurred during late hyphal extension.
5. The nucleic acid content increased sharply during swelling, and reached the highest value in swollen spores just prior to the initiation of germ-tube formation. Afterwards, its content steadily decreased during germ-tube formation and hyphae elongation.

     

Selective phonotaxis to advertisement calls in the gray treefrog Hyla versicolor: behavioral experiments and neurophysiological correlates

1. The significance of particular acoustic properties of advertisement calls for selective phonotaxis by the gray treefrog, Hyla versicolor (= HV), was studied behaviorally and neurophysiologically. Most stimuli were played back at 85 dB SPL, a level typically measured at 1–2 m from a calling male.
2. Females preferred stimuli with conspecific pulse shapes at 20° and 24°C, but not at 16°C. Tests with normal and time-reversed pulses indicated the preferences were not influenced by the minor differences in the long-term spectra of pulses of different shape.
3. Pulse shape and rate had synergistic or antagonistic effects on female preferences depending on whether the values of one or both of these properties in alternative stimuli were typical of those in HV or heterospecific (H. chrysoscelis = HC) calls.
4. More auditory neurons in the torus semicircularis were temporally selective to synthetic calls (90%) than to sinusoidally AM tones and noise (< 70%).
5. Band-pass neurons were tuned to AM rates of 15–60 Hz. Neurons were more likely to be tuned to HV AM rates ( < 40 Hz) when stimuli had pulses with HV rather than HC shapes.
6. Sharp temporal tuning was uncommon and found only in neurons with band-pass or low-pass characteristics.
7. Many neurons differed significantly in response to HV and HC stimulus sets. Maximum spike rate was more often elicited by an HV stimulus (74%) than by an HC stimulus (24%).
8. Differences in spike rates elicited by HV and HC stimuli were attributable to combinations of differences in the rise times and shapes of the pulses.

     

The anaerobic metabolism of malate of Saccharomyces bailii and the partial purification and characterization of malic enzyme

1. The main pathway of the anaerobic metabolism of l-malate in Saccharomyces bailii is catalyzed by a l-malic enzyme.
2. The enzyme was purified more than 300-fold. During the purification procedure fumarase and pyruvate decarboxylase were removed completely, and malate dehydrogenase and oxalacetate decarboxylase were removed to a very large extent.
3. Manganese ions are not required for the reaction of malic enzyme of Saccharomyces bailii, but the activity of the enzyme is increased by manganese.
4. The reaction of l-malic enzyme proceeds with the coenzymes NAD and (to a lesser extent) NADP.
5. The K _m-values of the malic enzyme of Saccharomyces bailii were 10 mM for l-malate and 0.1 mM for NAD.
6. A model based on the activity and substrate affinity of malic enzyme, the intracellular concentration of malate and phosphate, and its action on fumarase, is proposed to explain the complete anaerobic degradation of malate in Saccharomyces bailii as compared with the partial decomposition of malate in Saccharomyces cerevisiae.

     

The occurrence of the Entner-Doudoroff pathway in bacteria

The occurrence of the two key enzymes of the Entner-Doudoroff pathway, gluconate-6-phosphate dehydrase and 2-keto-3-deoxygluconate-6-phosphate aldolase, was determined in approximately 150 strains belonging to 37 different bacterial genera. The following results were obtained:

1. 24 out of 37 genera have at least one representative with the Entner-Doudoroff mechanism. It is thus more widespread than previously thought.
2. The Entner-Doudoroff mechanism occurs mainly in gram-negative bacteria with a DNA base composition in the range 52–70% GC. Eighty-five per cent of these organisms contain the system, while only 20% (6 strains) of the gram-negative organisms with less than 52% GC possess both enzymes.
3. This pathway is absent in all gram-positive organisms investigated except in 5 out of 12Nocardia strains.
4. Erwinia and some strains of theAchromobacter-Alcaligenes group are exceptional, since they possess only 2-keto-3-deoxygluconate-6-phosphate aldolase.

     

Changes in cell composition and viability of Bdellovibrio bacteriovorus during starvation

1. Washed cell suspensions of Bdellovibrio bacteriovorus harvested shortly after lysis of their substrate organisms and shaken in buffer have a constant and high endogenous respiration rate for a bout 6 h which then declines sharply to a rate approximately 10% of the original. Viability of cell suspensions shows little change over the first 4–6 h and then decreases by some 50% in 10 h.
2. Over the first 5–6 h of starvation there is a loss of about 50% of total cell carbon. This loss is distributed about equally between CO₂ and small molecules released into the suspending buffer. The protein and nucleic acid contents of the cells decrease concomitantly from time zero during starvation while DNA content remains constant. Ribosomal profiles show a rapid degradation of ribosomes.
3. In the presence of glutamate or glutamate plus a balanced amino acid mixture, loss of cell material and loss of viability is partially or completely prevented. There is extensive protein turnover when glutamate and an amino acid mixture are available to the bdellovibrio.
4. The pattern of changes observed in B. bacteriovorus during starvation is compared to reported changes in other species of bacteria, and the significances of its high endogenous respiration and sensitivity to starvation are discussed.

     

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.

     

Summer algal communities and primary productivity in fish ponds

The paper presents data on primary productivity and phytoplankton communities in new experimental ponds which received the following treatments; ammonium nitrate and triplesuperphosphate, triplesuperphosphate, cracked corn (10% crude protein) and Auburn No. 3 fish feed (36% crude protein). Comparative data on algal communities were also obtained from production ponds which received feeds or fertilizers. Basic ecological data on macro-algae are also presented.

1. All nutrient additions to experimental ponds resulted in higher levels of gross photosynthesis and greater concentrations of chlorophyll a than were found in the control treatments. Fertilization with both nitrogen and phosphorus gave the highest values. Chlorophyll a and gross photosynthesis were higher in ponds receiving high protein content feed (Auburn No. 3) than in ponds to which low protein content feed (corn) was applied.
2. Persistent blooms of blue-green algae occurred in ponds receiving nitrogen and phosphorus fertilization. Phosphorus only fertilization produced blooms of blue-greens, but these blooms did not persist as in the ponds to which nitrogen was also added. Control ponds were dominated by green algae. Blue-green algae were seldom abundant in feed treatments.
3. Production ponds had high level of gross photosynthesis and large concentrations of chlorophyll a.
4. Many of the production ponds which received feed applications developed heavy blooms of blue-green algae.
5. The major species of blue-green algae observed in the present study were Oscillatoria sp., Raphidiopsis curvata, Anacystis nidulans, A. aeruginosa, Spirulina sp., and Anabaena circinalis. Heterocyst bearing forms, which can presumably fix nitrogen, were seldom noted in ponds that received continuous additions of nitrogen from fish feeds.
6. Macro-algae are abundant in many fish ponds. Data illustrating the competition of macro-algae with phytoplankton are presented.

     

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.

     

A study on the rate of water transport of the clam katelysia opima in relation to environmental conditions

1. The neutral red technique was employed to study the rate of filtration in Katelysia opima.
2. The weight specific water filtration was found to be greater for younger clams compared to the older ones.
3. The rate of water filtration increased with decreasing salinity.
4. Water filtration was found to increase as temperature increased, reaching a maximum at 35°C. but then sharply decreasing at 39°C.
5. Light had no significant effect on the rate of filtration.
6. Suspended matter was found to affect the rate of water filtration.
7. The rate of filtration was low at high pH and high in low pH.
8. The rate of water filtration was found to be faster during high tide than during low tide.
9. The presence of the parasitic crab, Pennotheris sp., in the mantle cavity of clams had a marked effect on the particle filtration.
10. Accidental cut of the siphon tips had no effect on the rate of filtration.

     

An ecological study of the Ponggol Estuary in Singapore

1. An ecological study of the Ponggol Estuary was conducted from July 1965 to June 1966 and the seasonal data on physical, chemical and biological characteristics were presented.
2. The Ponggol River represents a short, narrow and shallow estuary in Singapore. The river mouth is open throughout the year and water from eastern Johore Straits drains in twice a day at high tide. The upper reach, however, is left exposed at low tide.
3. The Ponggol River was classified as a vertically and laterally homogeneous estuary and was found to exhibit a mesohaline to polyhaline environment.
4. Significant hydrological gradients from the river mouth 10 the upper reach were noted in the river system. Salinity, dissolved oxygen and pH increased towards the mouth of the river and other parameters such as nutrients, dissolved organic matter and turbidity increased towards the source.
5. Although the river received organic pollutants at the upper reach the estuary was able to discharge them fairly rapidly through regular flushing by the tides. The transient rise of organic matter did not appear to impart any serious affect on the biota in the estuary.
6. Over 98% of the phytoplankton consisted of diatoms, most of which were brought into the estuary from eastern Johore Straits. Freshwater forms were relatively few.
7. Phytoplankton biomass was considerably higher than the adjoining waters. and was reduced at the upper reach due to high turbidity of the water.
8. 80% of the zooplankton was composed of dinoflagellates,Difflugia, copepods and bivalve larvae dominating at all sections of the estuary.
9. Percentage composition of the zooplankton showed that dinoflagellates and copepod nauplii predominated at high tide whileDifflugia and bivalve larvae were abundant at low tide.
10. Zooplankton standing crop, in general, was higher towards the source at high tide but the reverse was found at low tide, i.e. standing crop increased towards the river mouth. This was attributed to the process of concentration.
11. Species composition of zooplankton was found to be more or less similar to that of the eastern Johore Straits.
12. The nekton consisted predominantly of small and juvenile fish. Close correlation of fish and copepods was found to be statistically valid and it was concluded that the fish entered the estuary to feed rather than to spawn.
13. The squids formed an important catch of the beach seine unit and were caught throughout the year.
14. The fish population could be grouped into four categories: estuarine components, euryhaline components, marine components and migratory components.
15. Benthic invertebrates were abundant. Commercially important species consisted of prawns,Metapenaeus andPenaeus, and crabs,Neptunus pelagicus andScylla serrata.
16. The river bed was inhabited predominantly by molluscs and the distribution resembled that of the sheltered shore of muddy-sand type.

     

Succession in Zoo- and phytoplankton in a sewage stabilization pond

The investigations pertaining to zoo- and phytoplankton succession during prestabilization and stabilization of domestic waste water in a facultative pond operating at 1.22 meters depth with an average BOD loading of 336.3 kg per hectare per day and a retention period of 10 days revealed the following:

1. A photosynthetic sulphur bacterium Thiocystis violacea has been recorded during the second and third day along with a considerable population of ciliate protozoa and algae.
2. Chlorophytes were followed by euglenoids in the ecological succession and the latter became predominant after the pond stabilized.
3. Of the twelve protozoan species Halteria grandinella, Bursaria truncatella and Perispira ovum were associated with peaks of algae and vigorous photosynthesis in the stabilized pond water.
4. There ia a gradual improvement in the quality of the waste water with respect to reduction in bacteria and biochemical oxygen demand and enhancement in changes in physico-chemical factors till a relatively stable community is evolved.

     

Tres adiciones al genero Baccharis (Compositae) en Mexico

1. -Bigelowia pyramidata Rob. & Greenm. from Oaxaca proves to be a dioecious plant and is therefore transferred to the genusBaccharis.
2. -Baccharis matudae sp. nov. is described on the basis of material collected in Zacatecas and San Luis Potosí. The species is closely related toB. pyramidata (Rob. & Greenm.) Rzedowski.
3. -Baccharis zamoranensis sp. nov. is described on the basis of material collected on the border of Querétaro and Guanajuato. The taxon is related toB. multiflora H.B.K., known from central and southern Mexico.

     

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.

     

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.