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Starvation Period (starvation + period)
Selected AbstractsCalorimetric investigations into the starvation response of Pseudomonas putida growing on phenol and glucoseJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2009Andreas Lißner Abstract Aims:, To investigate the stress response during nutrient deprivation, particularly with regard to the application of phenol as growth substrate of Pseudomonas putida with calorimetric measurements as a new method. Methods and Results:, The online and noninvasive measurement of the thermal power P0 permits the detection of microbial activity during the starvation period. While the results of the investigations with phenol reveal a significant loss of activity as a function of the temporal nutrient dosage, only a small loss of activity was detected by using glucose. Microbiological methods (colony forming units (CFU) and activity of catechol-2,3-dioxygenase) showed a loss of the enzyme activity at a constant CFU. The introduction of a simple decay parameter kD in the kinetic description of the growth process on phenol was sufficient for the successful kinetic modelling. Conclusions:, The combination of calorimetric measurements and the determination of the enzymatic activity proved the loss of activity of Ps. putida during the deprivation of the substrate phenol. Significance and Impact of the study:, The initial heat power (P0) proves to be a suitable parameter for the characterization of the physiological state of the culture and can be used for the regulation of nutrient supply in biotechnological process development. [source] Energy reserves during food deprivation and compensatory growth in juvenile roach: the importance of season and temperatureJOURNAL OF FISH BIOLOGY, Issue 1 2005P. L. M. Van Dijk The effect of 21 days of starvation, followed by a period of compensatory growth during refeeding, was studied in juvenile roach Rutilus rutilus during winter and summer, at 4, 20 and 27° C acclimation temperature and at a constant photoperiod (12L : 12D). Although light conditions were the same during summer and winter experiments and fish were acclimated to the same temperatures, there were significant differences in a range of variables between summer and winter. Generally winter fish were better prepared to face starvation than summer fish, especially when acclimated at a realistic cold season water temperature of 4° C. In winter, the cold acclimated fish had a two to three-fold larger relative liver size with an approximately double fractional lipid content, in comparison to summer animals at the same temperature. Their white muscle protein and glycogen concentration, but not their lipid content, were significantly higher. Season, independent of photoperiod or reproductive cycle, was therefore an important factor that determined the physiological status of the animal, and should generally be taken into account when fish are acclimated to different temperature regimes. There were no significant differences between seasons with respect to growth. Juvenile roach showed compensatory growth at all three acclimation temperatures with maximal rates of compensatory growth at 27° C. The replenishment of body energy stores, which were utilized during the starvation period, was responsible for the observed mass gain at 4° C. The contribution of the different energy resources (protein, glycogen and lipid) was dependent on acclimation temperature. In 20 and 27° C acclimated roach, the energetic needs during food deprivation were met by metabolizing white muscle energy stores. While the concentration of white muscle glycogen had decreased after the fasting period, the concentrations of white muscle lipid and protein remained more or less constant. The mobilization of protein and fat was revealed by the reduced size of the muscle after fasting, which was reflected in a decrease in condition factor. At 20° C, liver lipids and glycogen were mobilized, which caused a decrease both in the relative liver size and in the concentration of these substrates. Liver size was also decreased after fasting in the 4° C acclimated fish, but the substrate concentrations remained stable. This experimental group additionally utilized white muscle glycogen during food deprivation. Almost all measured variables were back at the control level within 7 days of refeeding. [source] Effect of food shortage and temperature on oxygen consumption in the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae)PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2003D. Renault Abstract., Temperature and food availability are limiting factors for the establishment of tropical insects in temperate countries. In the alien pest beetle, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), starvation and temperature have a significant impact on metabolic rate with oxygen consumption ranging from 0.5 µmol/g fresh mass (FM)/h at 12 °C to 3.4 µmol/g FM/h at 24 °C. At 12 °C, oxygen consumption decreased continuously during an entire period of starvation. However, at 16, 20 and 24 °C, beetles display a marked hyperactivity that leads to an increase in the oxygen consumption level during the first week of starvation, followed by a steep decrease until the end of the starvation period. Oxygen consumption either does not decline in fed beetles (observed at higher temperatures) or declines at a much shallower rate than in starved beetles (observed at cooler temperatures). During the first week of refeeding, Oxygen consumption rose steeply at 16, 20 and 24 °C before levelling off to the initial value (t0). At 12 °C, no compensation process was observed during recovery. This study reveals that an important threshold in the biology of A. diaperinus lies between 12 and 16 °C, leading to the onset of reduced locomotor activity and the promotion of survival to the detriment of reproduction. This ,sit and wait' behaviour is proposed as an adaptive strategy (i.e. inactivity and lower oxygen consumption coupled with low energetic requirements and high recovery abilities). Such behaviour and the observed hyperactivity were rarely described in insects before the present study. Together, the previous and present results suggest that A. diaperinus populations are likely maintained in temperate regions by immigration from warmer situations. [source] Short-term food deprivation does not improve the efficacy of a fish oil finishing strategy in Murray codAQUACULTURE NUTRITION, Issue 6 2009G. PALMERI Abstract Two groups of fish (Maccullochella peelii peelii) were fed for a 90-day conditioning period on a canola oil diet (CO) or a fish oil diet (FO). Canola oil diet fed fish were then shifted to the FO diet for a 90-day finishing period. A variable period of starvation (0, 5, 10 and 15 days) was introduced to reduce the initial lipid level of CO fed fish at the beginning of the finishing period and therefore accelerate the rate of recovery of FO-like fatty acids. During starvation, fish did not show significant reduction in total lipid content, either in the fillet or whole body. At the end of the conditioning period, fatty acid composition of the diet was mirrored in fish tissues. These differences came close to levelling out following re-feeding, with the exception of n - 6 polyunsaturated fatty acids (PUFA). However, no effects of the starvation periods on the final fatty acid make-up of fish were recorded. The results of this trial show that Murray cod, when subjected to a starvation period of up to 15 days, does not lose an appreciable quantity of lipid and, therefore, the tested starvation approach to reduce the initial level of lipid has to be considered unsuccessful. [source] Effect of intermittent starvation on growth and some antioxidant indexes of Macrobrachium nipponense (De Haan)AQUACULTURE RESEARCH, Issue 5 2009Zhi-Hua Li Abstract The effect of different periods of starvation (0, 2, 4 and 8 days) followed by re-feeding on growth, feed utilization, oxygen consumption and some immune indexes [reactive oxygen intermediates (ROIs), activities of superoxide dismutase (SOD) and catalase (CAT)] was evaluated over an 18-day experimental period in shrimp Macrobrachium nipponense (De Haan) that had an initial body weight of 0.52 g. As a result of compensatory growth, indicated by an increase in specific growth rate (SGR), feeding rate (FR) and feed conversion efficiency (FCE) after re-feeding, final body weight of shrimp starved for 2 days (0.63 g) and 4 days (0.65 g) did not differ (P>0.05) from the control group (0.64 g), with feed withholding for 8 days presenting a significant lower value (0.63 g). Oxygen consumption rate (OCR) decreased during the starvation period in all groups, followed by a gradual increase to a similar (P>0.05) value than found in the control group (0.47 mg kg,1 h,1) at the end of the experiment. Although ROIs and the activity of SOD and CAT fluctuated during starvation in the feed-deprived groups, values at the termination of the experiment were comparable (P>0.05) to those found for the control group. [source] Short-term food deprivation does not improve the efficacy of a fish oil finishing strategy in Murray codAQUACULTURE NUTRITION, Issue 6 2009G. PALMERI Abstract Two groups of fish (Maccullochella peelii peelii) were fed for a 90-day conditioning period on a canola oil diet (CO) or a fish oil diet (FO). Canola oil diet fed fish were then shifted to the FO diet for a 90-day finishing period. A variable period of starvation (0, 5, 10 and 15 days) was introduced to reduce the initial lipid level of CO fed fish at the beginning of the finishing period and therefore accelerate the rate of recovery of FO-like fatty acids. During starvation, fish did not show significant reduction in total lipid content, either in the fillet or whole body. At the end of the conditioning period, fatty acid composition of the diet was mirrored in fish tissues. These differences came close to levelling out following re-feeding, with the exception of n - 6 polyunsaturated fatty acids (PUFA). However, no effects of the starvation periods on the final fatty acid make-up of fish were recorded. The results of this trial show that Murray cod, when subjected to a starvation period of up to 15 days, does not lose an appreciable quantity of lipid and, therefore, the tested starvation approach to reduce the initial level of lipid has to be considered unsuccessful. [source] Effect of different diets on larval production, quality and fatty acid profile of the marine ornamental shrimp Lysmata amboinensis (de Man, 1888), using wild larvae as a standardAQUACULTURE NUTRITION, Issue 5 2009R. CALADO Abstract The present work evaluates the influence of broodstock diets [Marine Cuisine®, MC, MC supplemented with highly unsaturated fatty acid- (HUFA) enriched Artemia biomass , MC + AB, and MC supplemented with squid , MC + S] on larval production, newly hatched and early zoeal stage survival and fatty acid profile of newly hatched larvae of Lysmata amboinensis. These parameters are compared with those from larvae hatched from embryos spawned in the wild. The number (±SE) of larvae produced with MC and MC + S (1077 ± 219 and 1103 ± 184, respectively) was similar to that in broodstock carrying embryos spawned in the wild (1224 ± 111), while those fed MC + AB displayed significantly lower values (1044 ± 161). Larvae produced with MC + AB displayed lower survival for all starvation periods, while larvae spawned in the wild displayed the highest survival. No larvae resisted 144 h of starvation and none moulted to zoea II. The fatty acid comparison revealed that larvae from embryos spawned in the wild displayed the highest levels of DHA, as well as higher DHA/EPA and n -3/n -6 ratios. These results suggest that broodstock diets commonly used to promote ornamental shrimp's maturation (based on mixed frozen components) are far from being optimal. [source] High-pressure systems for gas-phase free continuous incubation of enriched marine microbial communities performing anaerobic oxidation of methaneBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2010Christian Deusner Abstract Novel high-pressure biotechnical systems that were developed and applied for the study of anaerobic oxidation of methane (AOM) are described. The systems, referred to as high-pressure continuous incubation system (HP-CI system) and high-pressure manifold-incubation system (HP-MI system), allow for batch, fed-batch, and continuous gas-phase free incubation at high concentrations of dissolved methane and were designed to meet specific demands for studying environmental regulation and kinetics as well as for enriching microbial biomass in long-term incubation. Anoxic medium is saturated with methane in the first technical stage, and the saturated medium is supplied for biomass incubation in the second stage. Methane can be provided in continuous operation up to 20,MPa and the incubation systems can be operated during constant supply of gas-enriched medium at a hydrostatic pressure up to 45,MPa. To validate the suitability of the high-pressure systems, we present data from continuous and fed-batch incubation of highly active samples prepared from microbial mats from the Black Sea collected at a water depth of 213,m. In continuous operation in the HP-CI system initial methane-dependent sulfide production was enhanced 10- to 15-fold after increasing the methane partial pressure from near ambient pressure of 0.2 to 10.0,MPa at a hydrostatic pressure of 16.0,MPa in the incubation stage. With a hydraulic retention time of 14,h a stable effluent sulfide concentration was reached within less than 3 days and a continuing increase of the volumetric AOM rate from 1.2 to 1.7,mmol,L,1,day,1 was observed over 14 days. In fed-batch incubation the AOM rate increased from 1.5 to 2.7 and 3.6,mmol,L,1,day,1 when the concentration of aqueous methane was stepwise increased from 5 to 15,mmol,L,1 and 45,mmol,L,1. A methane partial pressure of 6,MPa and a hydrostatic pressure of 12,MPa in manifold fed-batch incubation in the HP-MI system yielded a sixfold increase in the volumetric AOM rate. Over subsequent incubation periods AOM rates increased from 0.6 to 1.2,mmol,L,1,day,1 within 26 days of incubation. No inhibition of biomass activity was observed in all continuous and fed-batch incubation experiments. The organisms were able to tolerate high sulfide concentrations and extended starvation periods. Biotechnol. Bioeng. 2010; 105: 524,533. © 2009 Wiley Periodicals, Inc. [source] | |||||||||||||