Specific Respiration Rate Research Articles

Effect of Azospirillum brasilense inoculation on root morphology and respiration in tomato seedlings

The level of Azospirillum brasilense strain Cd colonization in the rhizosphere of some vegetables was 104–105 colony-forming units (CFU) per root of one plant in 2-week-old plants inoculated with 5 × 108Azospirillum cells. Significant increases in root length (35%) and in top (90%) and root (50%) dry weight and total leaf area (90%) were observed in 18-day-old inoculated tomato plants compared with non-inoculated controls. An inoculum concentration of 1 × 108 to 5 × 108 CFU/ml stimulated the appearance of root hairs. Large numbers of bacteria (1 × 109 CFU/ml) caused asymmetrical growth of the root tip. In a petri dish system, Azospirillum (1 × 108 CFU/ml) increased root dry weight (150%), protein content (20%), respiration rate per root (70%) and the specific activity of malate dehydrogenase (45%–65%) over non-inoculated controls. The specific respiration rate, expressed as micromol of O2 per minute per milligram of dry weight of roots, was significantly lower in inoculated roots, suggesting that less energy was spent for accumulation of more dry material.

Temperature effects on photosynthetic capacity, respiration, and growth rates of bloom‐forming cyanobacteria

Abstract The literature was reviewed to determine the direct temperature effects on photosynthetic capacity (Pmax), specific respiration rate (Rest), and growth rate of bloom‐forming cyanobacteria (Anabaena, Aphanizomenon, Microcystis, Oscillatoria) and to assess the importance of direct tern‐perature effects on cyanobacterial dominance in lakes. This analysis is supported by field studies of Microcystis aeruginosa in a hypertrophic lake. The literature and field data show that Pmax, Rest, and growth rate are temperature‐dependent with optima usually at 25 °C or greater. The four genera varied in their response to low temperatures with Microcystis being most severely limited belw about 15 °C. Oscillatoria tended to tolerate the widest range of temperatures. However, an examination of field data from representative lakes around the world indicated that direct temperature effects were secondary to indirect temperature effects (mixing) and nutrients in determining the dominance of bloom‐forming cyanobacteria...

Chemolithotrophic growth of the phototrophic sulfur bacteriumThiocapsa roseopersicina

Abstract Chemotrophic growth capacities of the purple sulfur bacterium Thiocapsa roseopersicina strain M1 were studied in continuous culture under thiosulfate limitation. Pigment synthesis was completely inhibited upon a shift from anaerobic to semi-aerobic conditions (52 μM O 2 ) in the light, but no active breakdown occurred. During the transient state, the cells grew in a mixed photo- and chemolithotrophic mode; the specific respiration rate gradually increased with a concomitant drop in the bacteriochlorophyll a content. Photolithotrophically grown cells have the ability to respire. It was concluded that photosynthesis and respiration compete for electrons, but that photosynthesis is preferred under electron donor-limiting conditions, when the cells still contain large amounts of pigments. Eventually, a fully chemolithotrophic steady state was attained. The chemolithotropic growth of T. roseopersicina was studied in the dark under semiaerobic conditions at various dilution rates. The maximum specific growth rate was 68% of the maximum attainable growth rate under photolithotrophic conditions. The growth affinity for thiosulfate was high ( K m = 1.5 μ M). The yield on thiosulfate under chemolithotrophic conditions exceeded that of thiobacilli. Oxygen uptake was studied in short-term experiments. It was shown that respiration in T. roseopersicina has a K m of approx. 1 μM O 2 . the ecological importance for T. roseopersicina of chemolithotrophic growth and pigment content is discussed with respect to the occurrence of T. roseopersicina in laminated microbial ecosystems and its possible competition with colorless sulfur bacteria.

Growth ofCandida utils on single- and multicomponent-sugar substrates and on waste banana pulp liquors for single-cell protein production

Large quantities of cull bananas are available world-wide, and often in regions lacking indigenous sources of high-quality protein animal feedstuffs. One possible method of utilizing these wastes is to upgrade them to microbial protein by means of bioconversion of the fermentable sugars of the ripe or over-ripe pulp by the yeastCandida utilis, which is nutritionally well-accepted. Studies of ripeMusa sapientum var. ‘Gros Michel’ bananas were conducted in order to obtain both the microbial and the engineering data necessary for the development of such an aerobic fermentation process. For banana pulp fermentation liquors in the concentration range 10 to 35% (w/v) fresh weight (FW) banana, the corresponding dry weight banana concentrations and the fraction of insoluble solids before and after sterilization (121°C, 30 min) have been measured and are reported. In addition to fermentation studies of banana liquor prepared from 10% (w/v) fresh whole banana, comparative kinetic studies of the batch growth and substrate assimilation pattern were performed on media containing as the sole soluble carbohydrate source either one of the major banana sugars (glucose, fructose, sucrose) or a mixture of the three. Wherever feasible, the maximum specific growth rate (μmax) was evaluated by four different methods: dry weight biomass, optical density, crude protein content of broth insoluble solids and dissolved oxygen history. In addition to the comparative μmax results, values of the biomass yield coefficient and the specific respiration rates for each case are presented and discussed. A preliminary process design of the fermentation section of a moderate-scale microbial protein production plant based on 20,000 kg FW banana/day feedstock is presented. The results of this study indicate that such a plant would yield about 2,900 kg/day of protein-enriched product containing 5 wt% moisture and 44 wt% (c. 1,400 kg/day) crude protein.

Chemoautotrophic growth of Thiocystis violacea, Chromatium gracile and C. vinosum in the dark at various O2‐concentrations

AbstractThe influence of various O2‐concentrations on chemoautotrophic growth was determined in the range from microaerobic to aerobic conditions. Chromatium vinosum D, Thiocystis violacea 2311 and Chromatium gracile 25‐1 were grown chemoautotrophically using consecutively repeated batch cultures. Rapid growth of all three strains occurred only under microaerobic conditions. The fastest growth (μ = 0.058) was obtained with Chromatium gracile 25‐1 grown in the presence of 1 mg O2 · 1−1. For optimal chemoautotrophic growth sulfur‐containing cells had to be supplied continuously with extracellular electron donor. Multiplication of thiocystis violacea 2311 and Chromatium gracile 25‐1 was significantly inhibited after several cell generations, while Chromatium vinosum D could be grown unlimited. In case of the latter bacterium any given O2‐concentration determined a unique growth rate and a unique specific bchl α content. The analysis of absorption spectra of whole cells revealed that different pigment complexes were regulated separately by oxygen. Growth yields were not dependent on the O2‐concentration. A growth yield of 12 g dry cell mass per mol of thiosulfate oxidized was determined for Chromatium vinosum D growing in the micro‐ to semiaerobic O2‐concentration range. When compared to phototrophically grown cells, the catalase content of chemotrophically grown cells was 2 times lower while the maximal specific respiration rate of the cells was 7 times higher. The ecological significance of the kinetics of chemotrophic growth under various growth conditions is discussed.

Respiratory studies on two benthic copepods Acanthocyclops viridis and Eucyclops agilis at environmental temperatures.

The rate of oxygen consumption in all developmental stages of two benthic cyclopoid copepod species, Acanthocyclops viridis (Jurine) and Eucyclops agilis (Koch, Sars) was investigated at temperatures between 5° C-20° C, which are reflective of the environmental temperature range of the benthic zone in Esthwaite Water, Cumbria, from which the organisms were derived. The larger species, A. viridis was found to have a temperature insensitive metabolism, whereas E. agilis showed a marked temperature response in respiratory function. Gravid and non-gravid females had similar rates of respiration except at 15° C-20° C in E. agilis. Males exhibited much lower respiration rates than females, but higher weight specific respiration rates; these differences were largely attributable to size differentials between the sexes. Estimates of swimming activity were made and these were related to the patterns of respiratory function observed.

The relationship between the rate of respiration and the protonmotive force. The role of proton conductivity.

It is shown by titrating a suspension of rat liver mitochondria with either ADP or an uncoupler that a specific rate of respiration may not have a unique associated value of the protonmotive force. Alternatively, a specific protonmotive force may not be associated with a unique rate of respiration. It seems that the rate of respiration and the protonmotive force are more sensitive to the agents used for the titrations than to each other. Such observations are not easily explained by the chemiosmotic hypothesis. It is, however, possible provided that the proton conductivities, i.e. the rates of dissipation of the protonmotive force, are considered to be different for each of the agents used to titrate the rate of respiration at the same protonmotive force, or vice versa.

New Activated Sludge Theory: Steady State

This theory emphasizes diffusion resistance to mass transfer in the floc particles and biopolymer production from recycled bacterial protoplasm. The diffusive effectiveness factor is a simple function of sludge age and hydraulic residence time. The diameters and settling velocities of the floc particles are predicted. Specific bacterial respiration rate, specific soluble substrate as‐similation rate, and floc settling velocity data from the literature are correlated by the theory.

Pea Fruit Extension Rate

Rates of respiration and extension of pea fruits maintained under different regimes of fruit (10 °C to 25 °C) and plant (15 °C to 30 °C) temperature were measured during prolonged darkness. Higher fruit temperatures resulted in faster maximum rates while higher plant temperatures were associated with slower maximum rates of fruit extension and respiration. Increasing the temperature of either part caused faster decay of rates in the dark; this effect being more apparent for respiration than for growth in length and for plant temperatures than for fruit temperatures. The relationship between maximum rates of growth and respiration for different temperatures was linear. There was an asymptotic curvilinear relationship between specific respiration and relative extension rates obtained during prolonged darkness. Analysis of these data using an exponential equation of the form showed that treatment regimes affected primarily the asymptote (A) of this equation. Estimates of the shape parameters (b and k) of the curve were very variable and no obvious treatment effects could be discerned. The form of these data is compared with those of other models for respiration.

Effect of dissolved oxygen on nitrogen fixation by A. vinelandii. II. Ionically adsorbed cells

Continuous culture studies of Azotobacter vinelandii cells immobilized by ionic adsorption to Cellex E anion exchange resin were conducted under oxygen-limited conditions for comparison to free-cell cultures. Immobilization had little effect upon the specific respiration and sucrose consumption rates as compared to free cells. However, maxima in specific nitrogen fixation rate and nitrogenase activity as a function of dissolved oxygen occurred at a C(O(2) ) value of approximately 0.005 mM as opposed to 0.02 mM for free cells. Further, in contrast to free-cell culture, most of the fixed nitrogen appeared in the medium rather than within intact cells. There were strong indications that reproduction of bound cells often resulted in cell lysis accounting for the fixed nitrogen content in solution.

A simple, steady state description of phytoplankton growth based on absorption cross section and quantum efficiency1

We present a simple, quantitative formulation of steady state growth and metabolic regulation by phytoplankton, which describes well the nutrient‐limited and light‐limited growth of Thalassiosira weissflogii. The specific growth rate is a function of the quantum efficiency of carbon assimilation, the absorption cross section of cellular carbon, the incident light level, and the specific rate of respiration. The quantum efficiency is solely a function of light level, the absorption cross section is a function of light level and nutrient supply, and the respiration rate is a function of specific growth rate. The formulation, which resembles those proposed by Bannister and Shuter, is consistent with the thermodynamic model of Kiefer and the principle of optimization of energy conversion.

Respiration, energy balance and development during growth and starvation of Carcinus maenas L. larvae (Decapoda:Portunidae)

In all larval stages of Carcinus maenas L. oxygen consumption was measured at three temperatures (12,18,25 °C). Values increased during development and were in the range of 0.037 ± 0.01 (zoea-1, 12°C, x ̄ ± 95% CL ) to 0.734 ± 0.047 μl O 2 · h −1 · ind −1 (megalopa, 25 °C). Growing larvae showed temperature dependent trends in weight specific respiration rates (referred to dry wt; DW), with values between ≈2.4 and 9.4 μl O 2· h −1·mg DW −1. Increase in oxygen consumption of megalops did not differ much at temperatures between 18 and 25 °C. This points to an exceptional physiological position of this stage. Fed zoea-1 of C. maenas (18 °C) revealed growth rates in terms of 40% DW, 20% carbon (C), 30% nitrogen (N) and 65% hydrogen (H). At the same time larvae gained individual energy by 13% (J · ind −1), while weight specific energy dropped by ≈ 19% (J · mg DW −1) during the first day and remained constant until the moult. Starved zoea-1 of C. maenas (18 ° C) gained ≈ 20 % in DW through the first day, probably caused by inorganic salts which enter the organism after the moult of the prezoea. DW dropped to ≈ 25 % of initial value, when starvation continued. Single components decreased by ≈50% (C), 54% (N), 57% (J · ind −1). Weight specific energy (J · mg DW −1) decreased by 40% during the first 4 days of starvation, remaining constant thereafter. Individual respiration rate ( R) dropped by 61 %, weight specific respiration rate ( QO 2) by 55 %. Individual energy loss in starved zoea-1 was 0.077 J over a period of 11 days. In this period ≈ 9.3 μl O 2·ind −1 were consumed. Thus effective oxygen capacity was lower than in growing larvae. It dropped to 5.3 J·mlO 2 −1 after 4 days and remained constant if starvation continued, i.e. 65 % of possible energy loss occurred during the first 4 days. Decrease in requirement for oxygen and its effective capacity were both recognized as independent components of survival during starvation. Partitioning of energy through individual larval development of C. maenas was investigated for all five larval stages. The cumulative budget could be calculated: consumption ( C) = 28.23 J, growth ( G) = 0.92 J, exoskeleton ( Ex) = 0.20 J, metabolism ( M) = 5.30 J, egestion and excretion ( E) = 21.82 J. Mean gross and net growth efficiency were, K 1 = 3.3% and K 2 = 14.8%, respectively.

A COMPARISON OF GROWTH EFFICIENCY AND SPECIFIC RATE OF DARK RESPIRATION OF UNINFECTED AND VESICULAR‐ARBUSCULAR MYCORRHIZAL PLANTS OF TRIFOLIUM SUBTERRANEUM L.

SummarySmall swards of mycorrhizal and non‐mycorrhizal subterranean clover plants were grown in an artificial rooting medium in pots so as to form a closed canopy, by which time plants were about 5 weeks old and had 30 % infection in mycorrhizal roots. Specific rates of dark respiration of mycorrhizal and uninfected populations of plants were compared in an incubation chamber after exposure of the sward to standard light flux density and temperature on a 12 h day/12 h night cycle. Growth efficiencies were measured by exposing a sward to variable light flux density at constant temperature and monitoring the CO2‐exchange rate.The dark respiration rate of whole plants decreased during darkness from an initial value measured immediately after the start of incubation to one about 20% lower after 12 h. Rates for excised roots decreased to about 35% of the initial value. When compared on the same basis the specific rate of dark respiration of mycorrhizal plants did not differ from that of uninfected plants. Likewise, mycorrhizal plants and uninfected plants displayed the same growth efficiency, for both used about 30 % of the net CO2 gain during the light period for purposes of biosynthesis. This parameter was not affected by phosphate nutrition. Mycorrhizal and uninfected plants responded to change in light flux density in a similar manner.It is concluded that when CO2 fluxes are measured on a whole‐plant basis over a 24 h period, mycorrhizal and uninfected plants of subterranean clover grown as swards, have essentially similar carbon economies.

Effects of diurnal fluctuations in light intensity on the efficiency of growth of Skeletonema costatum (Grev.) Cleve (Bacillariophyceae) in a cyclostat

The effects of diurnal variations in light intensity on the biomass characteristics and the efficiency of daily growth of Skeletonema costatum (Grev.) Cleve were evaluated. The relative importance of changes in carbon specific rates of respiration and organic release to the efficiency of growth was determined. Light intensity was either constant at 130 μE · m −2 · s −1 during the light period or fluctuated throughout the light period from 500 to 10 μE · m −2 · s −1 at rates of either 1 or 12 cycles · day −1. Total daily light was equivalent for all light regimes at 5.6 E · m −2 · day −1. Daily rates of growth remained comparable at ≈ 1 · day −1 under constant and fluctuating light regimes. Cell size as daily mean carbon · cell −1, nitrogen · cell −1 and cellular volume was decreased under diurnally varying light whereas daily mean chlorophyll a · cell −1 was unaffected. Rates of respiration, organic release and gross production were elevated several fold under diurnally varying light in comparison to constant light. Net growth efficiency decreased from 0.69 under constant light to values of 0.50 and 0.38 under 1 and 12 cycles · day −1, respectively. Decreased efficiency of growth under diurnally fluctuating light resulted mostly from greater respiratory activity while organic release remained < 10% of gross production. Increased rates of gross production reflected enhancement in the efficiency of carbon fixation with fluctuating light.

Ecological Studies and Mathematical Modeling of Cladophora in Lake Huron: 3. The Dependence of Growth Rates on Internal Phosphorus Pool Size

The relationship between growth rate and internal phosphorus pool size was examined using field populations of Cladophora glomerata from Lake Huron. Algal samples, representing a range of internal phosphorus concentrations, were harvested from the lake and used for laboratory measurements of growth. Rates of net photosynthesis and respiration were measured under controlled conditions of light and temperature using a dissolved oxygen (light/dark bottle) technique. The net specific growth rate and respiration rate were calculated from photosynthesis and respiration measurements using a fixed stoichiometric relationship and the measured carbon content of the algae. The maximum rates for net specific growth rate, gross specific growth rate, and specific respiration rate were 0.77, 1.08, and 0.44 day −1, respectively. Management decisions may be importantly influenced by the relationships derived from these data. A non-linear response by growth to reductions in phosphorus loading is suggested from the results of these experiments. The internal nutrient status of algal populations (e.g. Cladophora) must be considered in predictions of the impact of phosphorus management strategies on aquatic systems.

Ecological Studies and Mathematical Modeling of Cladophora in Lake Huron: 4. Photosynthesis and Respiration as Functions of Light and Temperature

Laboratory experiments were conducted with Cladophora glomerata isolated from Lake Huron near Harbor Beach, Michigan, to determine gross and net photosynthesis and respiration as functions of temperature and light intensity. Rates of net photosynthesis and respiration were measured in three replicate cultures at all combinations of eight temperatures (1° to 35° C) and eight light levels (12 to 1235 μE/m 2•sec) using oxygen electrode techniques. Maximum net photosynthesis occurred between 13 and 17° C and 300 to 600 μE/m 2•sec. The data were converted to specific rates of growth and respiration for use in a mathematical model, and three-dimensional response surfaces were generated for gross and net growth and respiration over the entire range of light levels and temperatures examined.

Capacity of chromatiaceae for chemotrophic growth. Specific respiration rates of Thiocystis violacea and Chromatium vinosum

The capacity for chemoautotrophic, mixotrophic and organotrophic growth in the dark was tested with 45 strains of 17 species (11 genera) of the Chromatiaceae. The auxanographic deep agar shake culture method was used; the gas phase contained 5% O2 and 1% CO2 in N2. All strains tested of Chromatium vinosum, C. minus, C. violascens, C. gracile, Thiocystis violacea, Amoebobacter roseus, Thiocapsa roseopersicina gave positive growth responses under chemoautotrophic and mixotrophic conditions (extra carbon source acetate); one strain of Thiocapsa roseopersicina grew also organotrophically on acetate alone. No growth was obtained with the remaining 17 strains of ten species. None of the five type species (three genera) of the Chlorobiaceae grew under chemotrophic conditions. With Thiocystis violacea 2311 a growth yield of 11.3g dry weight per mol thiosulfate consumed was obtained under chemoautotrophic conditions; under mixotrophic conditions with acetate the yield increased to 69g dry weight per mol thiosulfate consumed. With Thiocystis violacea 2311 maximal specific respiration rates were obtained with thiosulfate as electron donor irrespective of the presence or absence of sulfur globules in the cells; organic substrates served as carbon sources only and did not support respiration. With Chromatium vinosum D utilization of thiosulfate was not constitutive; maximal respiration rates on thiosulfate were obtained only with thiosulfate grown cells containing sulfur globules. Respiration rates were further increased by malate, fumarate or propionate; these substrates also served as sole electron donors for respiration. Acetate and pyruvate were used as carbon sources only. The ecological significance of the chemotrophic metabolism is discussed.

Energy requirement for maintenance of the transmembrane potassium gradient in Klebsiella aerogenes NCTC 418: A continuous culture study

With a glucose-limited culture of Klebsiella aerogenes, growing at a fixed dilution rate (0.4 h-1), the specific respiration rate varied progressively as a function of the transmembrane K+ gradient. The latter was varied by changing the input K+ concentration and, under these conditions, the specific respiration rate was linearly related to the electrochemical potential of the K+ gradient. Increasing or decreasing the transmembrane K+ gradient in putatively potassium-limited cultures elicited marked changes in respiration rate consistent with the conclusion that the exceptionally high respiration rates expressed by fully glucose-sufficient potassium-limited cultures (i.e., values in excess of 25 mmol O2/g dry weight organisms . h, at D = 0.4 h-1) are necessary to scavenge traces of K+ from the environment and hence maintain an exceptionally high transmembrane K+ gradient.

Population Dynamics, Bioenergetics, and Role of Lepidostoma Quercina Ross (Trichoptera: Lepidostomatidae) in an Oregon Woodland Stream

The aim of this study was to gather quantitative field and laboratory data on the utilization of deciduous leaves as food by Lepidostoma quercina Ross (Trichoptera: Lepidostamatidae) and estimate the effect of this food processing on the stream ecosystem. Samples were taken monthly in a riffle—pool section of Berry Creek, Benton County, Oregon. Maximum larval density was 382 per m2, instantaneous growth rate was 2.7% per day, instantaneous mortality rate was 1.4% per day, and production was 0.19 g·—2·—1. The life cycle of L. quercina and its period of maximum larval growth correspond closely with the period of maximum availability of its prefered food (alder leaves) in the stream. Consumption and fecal production rates were measured gravimetrically. Rates (mg·—1·—1) increased with temperature, food quantity, and conditioning time of the leaves, and decreased with increased size of the larvae. Mean respiration rates of larvae were higher at 10°C than at 5°, but there was no significant difference in mean rates at 10, 15, or 20°C. Respiration rate decreased with increased size of the larvae. Size—specific respiration rates showed regulation of respiration with respect to temperature for small individuals (present in the field in September and October when temperatures are variable) and little or no regulation by large individuals (present in December and January). Stimulation modeling of larval growth based on laboratory data demonstrated that growth and production of L. quercina in the field may be limited by a lack of high—quality food (alder leaves) in late summer and early fall. Consumption of leaves by the simulated population was estimated as 3.1 g·—2·—1. Lepidostama quercina comprised only a small part of the secondary production in Berry Creek (0.19g·—2·—1, vs. 2.2 g·—2 for simuliids) and processed only a small portion of the allochthonous input to the stream. However, significant quantities of fecal material were produced and it was estimated that these fine particle would be sufficient to support ¼ to ½ of the production of simuliids, the dominant riffle species in Berry Creek.

On weight dependence of net growth efficiency and specific respiration rates among field populations of invertebrates.

Annual net growth efficiency (NGE) is approximated here by 100 P a/(P a+R a), P a and R a being the annual production and respiration rates of populations per unit area. Published NGE values for 15 temperate invertebrate populations range from 13 to 55%. Contrary to the literature on NGE among speices, the dependence of NGE on species size (as body weight at the onset of sexual maturity, W s) is not yet determined although the ranges of P a and R a, divided by the mean biomass [Formula: see text], approach two orders of magnitude. The [Formula: see text] rates of 13 of these populations decline with a -0.35 power of W s rather than the -0.25 power of comparative physiology. A possible reason may be a trend towards larger specimens (relative to W s or full size) in populations of larger species. Among species, a significant dependence of NGE on W s (or full size) is not demonstrable for laboratory populations of unicellular organisms and field populations of mammals so that the cost per unit of production might generally be independent of the rate of production by the population.