Course Of Starvation Research Articles

The effect of CART on pituitary hormones release from cultured pituitary cells harvested from fasted and fed ad libitum male rats

Cocaine and Amphetamine-Regulated Transcript (CART) is widely expressed in the central nervous system and in several endocrine organs. CART is an important factor in the regulation of energy homeostasis. The aim of the study was to assess the role of CART in physiological response of pituitary cells in a course of starvation. The pituitary cells harvested from starved and fed ad libitum male rats were cultured for 48h and treated with: 0.1nM, 1nM, 10nM or 100nM doses of CART. The medium was collected after 60min and stored at −70°C until samples were further assayed for: LH, FSH, PRL, GH, TSH and ACTH. We revealed that in cultures of pituitary cells collected from fasted rats the basal levels of the examined hormones were reduced. Incubation of pituitary cells of non-starved rats with any dose of CART reduced the concentration of LH and TSH, while the levels of the other hormones were decreased after administration only specific doses of CART. In cells of fasted rats no change in the concentration of gonadotrophins was observed. The PRL level was increased only in the 1nM dose of CART, while the 10nM and 100nM CART doses markedly enhanced GH and TSH. Moreover, administration of 1nM, 10nM and 100nM of CART to cultured cells of fasted rats resulted in a significant rise of the ACTH.Our results indicate that CART can directly affect the physiological release of PRL, ACTH, TSH and GH in pituitary cells of starved animals. Moreover, CART did not alter the LH and FSH suppression level, which is correlated with food deprivation. This data stays in contrast with the already proposed role of CART as an anorexigenic hypothalamic factor.

Building a model of ammonium excretion in two species of marine zooplankton based on glutamate dehydrogenase kinetics

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 550:83-99 (2016) - DOI: https://doi.org/10.3354/meps11700 Building a model of ammonium excretion in two species of marine zooplankton based on glutamate dehydrogenase kinetics I. Fernández-Urruzola1,*, N. Osma1, M. Gómez1, S. Montesdeoca-Esponda2, T. T. Packard1 1Marine Ecophysiology Group (EOMAR), Universidad de Las Palmas de Gran Canaria, 35017, Spain 2Environmental Chemical Analysis Group, Universidad de Las Palmas de Gran Canaria, 35017, Spain *Corresponding author: ifernandez@becarios.ulpgc.es ABSTRACT: NH4+ production in 2 species of marine zooplankton was predicted from glutamate dehydrogenase (GDH) activity using general bisubstrate enzyme kinetics during a period of starvation. In addition to starvation, we studied the effect of food quality on both NH4+ excretion rates (RNH4+) and the biochemical composition of zooplankton. The mathematical function used here relies on Michaelis-Menten principles and assumes that the synthesis of NH4+ is controlled mainly by the maximum velocity of GDH, the intracellular pool of substrates and the kinetic constants. This simple model described reasonably well the shifts in RNH4+ that occurred within the time course of starvation in both groups of zooplankton. The calculated RNH4+, however, underestimated the actual RNH4+. Furthermore, we used single substrate kinetics to address the magnitude of either the allosteric inhibition or the activation by purine nucleotides. We found that allosterism is more important in healthy physiological conditions. Overall, the use of first-principles kinetics seems to provide better estimates of RNH4+ than applying a general GDH/RNH4+ ratio on the measurements of GDH; therefore, its application may be of potential interest when studying zooplankton RNH4+ in heterogeneous marine ecosystems. KEY WORDS: Glutamate dehydrogenase · NH4+ excretion · Biochemical kinetics · Brachionus plicatilis · Leptomysis lingvura Full text in pdf format PreviousNextCite this article as: Fernández-Urruzola I, Osma N, Gómez M, Montesdeoca-Esponda S, Packard TT (2016) Building a model of ammonium excretion in two species of marine zooplankton based on glutamate dehydrogenase kinetics. Mar Ecol Prog Ser 550:83-99. https://doi.org/10.3354/meps11700 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 550. Online publication date: May 25, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

On the edge of death: Rates of decline and lower thresholds of biochemical condition in food-deprived fish larvae and juveniles

Gaining reliable estimates of how long fish early life stages can survive without feeding and how starvation rate and time until death are influenced by body size, temperature and species is critical to understanding processes controlling mortality in the sea. The present study is an across-species analysis of starvation-induced changes in biochemical condition in early life stages of nine marine and freshwater fishes. Data were compiled on changes in body size (dry weight, DW) and biochemical condition (standardized RNA–DNA ratio, sRD) throughout the course of starvation of yolk-sac and feeding larvae and juveniles in the laboratory. In all cases, the mean biochemical condition of groups decreased exponentially with starvation time, regardless of initial condition and endogenous yolk reserves. A starvation rate for individuals was estimated from discrete 75th percentiles of sampled populations versus time (degree-days, Dd). The 10th percentile of sRD successfully approximated the lowest, life-stage-specific biochemical condition (the edge of death). Temperature could explain 59% of the variability in time to death whereas DW had no effect. Species and life-stage-specific differences in starvation parameters suggest selective adaptation to food deprivation. Previously published, interspecific functions predicting the relationship between growth rate and sRD in feeding fish larvae do not apply to individuals experiencing prolonged food deprivation. Starvation rate, edge of death, and time to death are viable proxies for the physiological processes under food deprivation of individual fish pre-recruits in the laboratory and provide useful metrics for research on the role of starvation in the sea.

Oxidative Stress and Antioxidant Defenses after Long-term Fasting in Blood of Chinese Sturgeon (Acipenser sinensis)

The effects of long-term fasting on the oxidative stress and antioxidant defenses in juvenile Chinese sturgeon (Acipenser sinensis) were studied. The oxidative stress biomarkers included lysozyme (LSZ), the ability of inhibiting hydroxyl radicals (AIHR), and total antioxidant capacity (T-AOC). The juvenile Chinese sturgeon were fasted for 24 hours at first. Blood samples were taken from fish a total of 8 times, upon sampling every 6 days during the remaining 48-day starvation period. The LSZ activity of juveniles generally increased as the starvation time increased. Furthermore, a significant difference in the LSZ activity of juveniles starved for 43 days was found compared with four groups starved for 1–19 days. In addition, the AIHR of juveniles first increased and subsequently decreased over the course of starvation. Specifically, the AIHR of juveniles was significantly higher in fish after 19 days of starvation than in fish sampled after 37 days of starvation, although there were no other significant differences among the levels for the other groups. The variation of the T-AOC levels of juveniles was higher during the earlier stage of starvation, and was decreased after 19 days of starvation. However, there were no significant differences among the T-AOC groups, except the T-AOC of juveniles starved for 13 days was significantly higher than that of fish starved for 37 days. It's concluded that long-term fasting influenced the antioxidant capability of juvenile Chinese sturgeon.

Effect of short-term starvation of adult Antarctic krill, Euphausia superba, at the onset of summer

We investigated the effect of short-term starvation (18 days) on the physiology of adult Euphausia superba from the Lazarev Sea at the onset of summer. Metabolic data, elemental and biochemical composition as well as morphological parameters revealed that, at the beginning of the experiment, krill was in transition from winter to summer physiology, with some features typical for late winter/spring (low lipid reserves, low C:N ratio, elevated O:N ratio) and others for summer (high respiration rates, high MDH activity, large green digestive gland, short intermoult period (IMP) and fast growth). Starvation reduced body reserves drastically by more than 1% C per day. In relative terms, lipids (40%) and glycogen (30%) were reduced most and proteins by 10% of the initial value. Absolute consumption, however, was approximately 4% DM for lipids and proteins each, whereas contribution of glycogen was negligible. Within lipids, triacylglycerols (TAG) and phospholipids (PL) fell most dramatically from already low levels by 84% and 39%, respectively. Phosphatylcholine (PC) constituted 57% of PL and declined by 46%. As a result, proportions of the lipid classes changed with sterols increasing relatively. Metabolite changes were similar in cephalothorax and abdomen, although TAG in the cephalothorax fell more drastically. High metabolic activity at the beginning of starvation was quickly reduced to reach 53% after 18 days, accompanied by a reduction in the abdominal activity of malate dehydrogenase (MDH) by 25%. Our results may provide some explanation why recruitment of some year-classes of krill fails. Despite execution of the experiment in spring (i.e. transitional physiology state) and its short duration, some changes in the activity of metabolic enzymes in the abdomen, representing lipolytic, glycolytic and proteolytic pathways, respectively, were measured. Rising activities of 3-hydroxyacyl-CoA dehydrogenase (HOAD) and glyceralaldehyde-3-phosphate dehydrogenase (GAPDH) indicated increased lipolytic and glycolytic fluxes, respectively, whereas declining glutamate dehydrogenase (GluDH) activity suggests reduced proteolytic flux. Activities of other enzymes from protein catabolism, alanine aminotransferase (AlaAT) and aspartate aminotransferase (AspAT), however, remained unchanged. Ratios calculated from these trends indicated a declining importance of protein use during the course of starvation compared with consumption of lipids and glycogen. These results suggest that constant-proportion enzymes from different catabolic pathways, and calculated ratios thereof, may be useful in detecting shifts between the consumption of different body reserves.

A transfer membrane method for in situ detection and quantification of trehalase

A method for the detection and quantification of trehalase activity (EC 3.2.1.28) by immobilization to a membrane support has been developed. Protein samples partly enriched for porcine and Galleria mellonella wax moth larvae trehalase activities were fractionated by polyacrylamide gel electrophoresis, followed by electrophoretic transfer to PVDF membranes, and incubated in a solution containing trehalose (20 mg/ml), glucose oxidase (40 U/ml), phenazine methosulfate (0.06 mg/ml), and nitro blue tetrazolium (0.24 mg/ml) in 20 m m sodium phosphate buffer, pH 6.5. The intensity of the red-colored bands, developed directly on the membrane, was quantified using a computing, laser densitometer and shown to be linearly proportional to the original enzyme activity in extracts determined by liquid assay. The temperature inactivation profile of wax moth trehalase was measured. Alteration of the electrophoresis sample buffer composition further revealed the presence of putative trehalase isoforms in wax moth larval extracts whose relative levels of activity were altered during the course of starvation and infection with Tipula iridescent virus.

Mobilization of copper among tissues in the estuarine crabScylla serrata(Forskal) under imposed starvation

The quantitative changes in copper free and bound to proteins in haemolymph and different forms of copper in muscle and hepatopancreas under imposed starvation were studied in the estuarine mud crab Scylla serrata. During the course of starvation, both haemolymph copper free and bound to proteins significantly declined and the regression analyses of these data further revealed that the haemolymph copper-free proteins were more affected than copper-bound proteins. The multiple stress condition namely injury and exsanguination along with starvation resulted in an earlier release and/or degradation of both these proteins. Hepatopancreas periodically accumulates and releases copper during starvation. The copper levels in haemolymph and hepatopancreas during different days of starvation showed a close inverse relationship between these two tissues. These changes in hepatopancreas were predominantly reflected in the copper that exists in association with low molecular weight substances. It is found that the copper thus accumulated was partly released back into haemolymph and a fraction may be excreted. This study also indicates the major role played by the low molecular weight substances in accommodation, detoxification and mobilization of copper in the decapod hepatopancreas during imposed starvation.

Cyanide-resistant respiration of [formula omitted] in course of starvation

The inhibition of respiration of Physarum polycephalum microplasmodia by KCN varies between 30% and 70% of initial rate of O 2 uptake, depending on the time of starvation. The kinetics of the development of cyanide-resistant respiration and its sensitivity toward salicylhydroxamic acid (SHAM) point out that CN-resistant respiration represents the activity of the alternative pathway of the electron transport. There is no evidence that during starvation the alternative pathway of respiration is active in the absence of cyanide.

Growth, condition and specific dynamic action in the mussel Mytilus edulis recovering from starvation

Juvenile Mytilus edulis were grown individually in plastic racks in a tidal salt marsh for 72 d in 1984, starved in the laboratory for 130 d, and then fed the alga Isochrysis galbana daily for 64 d. Oxygen consumption was measured at various times during the course of starvation and recovery. The effects of both size (tissue dry weight) and condition (tissue size relative to shell size) on the rate of oxygen consumption during the course of starvation and recovery were analyzed by multiple regression. Weight-specific preprandial rate was inversely correlated with both size and condition. Weight-specific active rate (measured shortly after feeding) was correlated with size but not condition. Relative Scope for Activity was inversely correlated with size and positively correlated with condition. Relative Specific Dynamic Action (RSDA; the integrated physiological and mechanical response to a meal) was initially correlated negatively with size and subsequently positively with condition. Glycogen content was shown to be positively correlated with condition in mussels before starvation and during recovery. During recovery, experimental mussels returned to 90% of their estimated dry weight prior to starvation, and from 53% after starvation. At weekly intervals during recovery, oxygen consumption was measured following a meal until it returned to the preprandial rate. Both pre- and postprandial volumes (μl at STP) of oxygen consumed per hour (\(\dot V\)O 2pre and \(\dot V\)O 2post , respectively) increased significantly during recovery. The postprandial rise in oxygen consumption increased significantly from 15% to 23% of \(\dot V\)O 2pre . At the end of the recovery period, RSDA [(\(\dot V\)O 2post −\(\dot V\)O 2pre )/\(\dot V\)O 2pre ] was independent of final dry weight, but was significantly correlated with percent dry weight recovered (r2=0.44; df=10; P<0.02). The increase in RSDA may reflect increased utilization of food and its conversion to soma during recovery from starvation, as distinct from mechanical energy expenditure (feeding activity) following a meal.

Significance of periodic fluctuations in the haemolymph proteins and their catabolic products during starvation and repeated injury in Scylla serrata (Forskal)

AbstractThe fate of haemolymph proteins during the course of prolonged starvation was investigated. Two different experimental protocols were set up. In experiment 1, sampling of the haemolymph was done in a group of six crabs at 3‐day intervals up to 33 days (group 1). In experiment 2, separate groups of crabs were sampled at 3‐day intervals up to 33 days (group 2).There is no change in body weight. The haemolymph volume and water increase significantly indicating hydration of haemolymph. The haemolymph protein concentration and quantity decline significantly in both groups during the course of prolonged starvation. Concomitantly, the haemolymph free amino acids concentration and quantity increase in both the groups, indicating degradation of protein during the course of starvation.That degradation of protein cannot occur continuously but rather takes place on specific days in both groups is indicated by the increase in the products of protein catabolism—namely, free amino acids and ammonia. The results also provide evidence for the mobilization of proteins from storage sites. Nonprotein dry weight increases markedly during the course of starvation, the significance of which is discussed.

Histidine starvation and adenosine 5'-triphosphate depletion in chemotaxis of Salmonella typhimurium.

Starvation for histidine prevented tumbling in Salmonella typhimurium hisF auxotrophs, including constantly tumbling strains with an additional mutation in cheB or cheZ. However, histidine-starved cheZs hisF strains were not defective in flagellar function or the tumbling mechanism since freshly starved auxotrophs tumbled in response to a variety of repellents. Tumbling in histidine-starved S. typhimurium could be restored in 13 s by addition of adenine or in 4 min by addition of histidine. Chloramphenicol did not prevent restoration of tumbling by these substances. Assays of adenosine 5'-triphosphate were performed based upon previous demonstration of adenine depletion in hisF auxotrophs starved for histidine. The adenosine 5'-triphosphate concentration dropped rapidly during the course of starvation, falling to less than 5% of the initial level as the cells ceased tumbling entirely. The change to smooth motility was prevented by 2-thiazolealanine, which inhibits phosphoribosyltransferase, thereby preventing adenine depletion during histidine starvation. These results suggest that an adenosine 5'-triphosphate deficiency was responsible for the change in tumbling frequency.

Experimental ultrastructural study on stimulation of the rat gastric endocrine cells. In vitro distension of the stomach by air inflation

The effect of distension of the stomach by air (in vitro) upon the ultrastructural picture of gastric endocrine cells in rats starved for 72 hours was investigated. Distension of the stomach by air in vitro, lasting for 5, 10, 15 and 20 minutes, resulted in massive dissolution of gastrin granules that had accumulated in the course of starvation. In AL, D1, EC and ECL cells distension of the stomach by air failed to induce dissolution of granular content or release of granules by any other mechanism. In AL and D1 cells accumulation of secretory granules caused by starvation was observed, the ultrastructure of EC and ECL cells remained unchanged both under the effect of starvation and distension. Dilatation of endoplasmic reticulum profiles as well as other changes on some cell organelles observed on endocrine cells after distension of the stomach by air in vitro are due to the effect of autolysis.

The influence of amino acid starvation on the UV reversibility of the strains ofEscherichia coli B/rthy − trp − Hcr + andEscherichia coli B/rthy − trp − Hcr −

The fraction of inducedtrp+ reversions in the strains ofEscherichia coli B/rthy−trp−Hcr+ andEscherichia coli B/rthy−trp−Hcr− was studied in the course of starvation for an essential amino acid. UV light as a mutagenic factor was used. It was found that there is a decrease in the proportion of inducedtrp+ reversions in the strain ofHcr+ type during starvation. Such a decrease was however observed only with that fraction oftrp+ reversions which is expressed in selective plates where several divisions of irradiated cells are caused. The proportion oftrp+ reversions expressed on minimal plates does not change during starvation. With the strain ofHcr− type the proportion of inducedtrp+ mutations remains unaltered irrespective of the nature of the selective plates.

Influence of Age and Water Balance on Spiracular Behavior in Aedes Mosquitoes1

In female Aedes triscriatus (Say) (Diptera: Culicidae), duration of spiracular opening in air declined with sample age; in response to 0.5% CO2, both amplitude and duration of opening declined. There was no relationship of frequency of spiracular opening to age. Aspects of feeding behavior were observed and related to spiracular behavior in A. triseriatus and A. acgypti (L.). In the former species there was a diurnal weight loss; in both species inclusion of 0.2M KC1 in 0.3M sucrose solution led to a reduction in the amount of fluid imbibed. Spiracular opening became conservative in A. triseriatus , and to a lesser extent in A. acgypti when KC1 was included in the diet. A. acgypti engorged more than A. triseriatus and showed looser spiracular control. The course of starvation was more rapid in A. triseriatus than in A. acgypti ; the rate of water loss in the former was 4 times that in the latter. Each species showed increasingly conservative spiracular behavior as starvation proceeded.

Changes in hemolymph total solids and blood volume of the greater wax moth, Galleria mellonella, during the course of starvation

The refractive index of hemolymph in both control and starved insects ( Galleria mellonella) rose during the first 10 days of experimentation. From this time on, hemolymph total solids fell in starved larvae but continued to rise in control larvae. No significant changes were observed in the relative blood volumes in both groups, while the amount of hemolymph increased during larval development and decreased during starvation.

Studies of Piglet Husbandry in Jamaica. II: Principal Causes of Loss Between Birth and Weaning

The new pig industry in Jamaica, as in most other countries, has losses of approximately 20 per cent in piglets up to one month of age. Most losses occur in the first week post-partum, and are attributable to trauma and inanition. Trauma and inanition accounted for 10 and 7 per cent, respectively, of deaths in the 1,267 live-born piglets studied here. Trauma tends to occur when the dam is in the process of lying down; this is so particularly when the litter is large (i.e. over 14) and then more in the litters of certain sows than in others ( P < 0.05). Some piglets are apparently predisposed to being overlain (the main type of trauma) by a prior disorder such as inanition. Inanition is often associated with a disturbance of the nursing relationship within the litter or between the litter and sow. The course of starvation is characterized by frequent nursing attempts, restlessness, disorientation, shivering, collapse, gulping, coma and death. The prodromal phase of inanition could be recognized by the disorientation of the piglets, and by the absence of the typical satiated behaviour in which they lie prone after sucking.

ウナギの代謝と体成分に及ぼす飢餓の影響

Eels taken from eel-culturing ponds in August and November were starved for three months at temperatures of 28 and 12°C, respectively. Oxygen consumption rate did not changed in relation to the duration of starvation. Nitrogen excretion, however, lowered remarkably during the initial 15 days, followed by a constant level, in three month starvation either at the high or low temperature. Relative liver weight of starved eels decreased rapidly during the initial 15 days followed by a nearly constant level at the high temperature, while at the low temperature it decreased at a rather constant rate throughout the experimental period of three months. The same tendency was also observed with the liver glycogen and the liver fat. It was found that weight, glycogen and fat of eel liver undergo more rapid and pronounced changes than those of carcass particularly in the early stages of starvation. Among three reserved substances, glycogen, fat and protein, glycogen shows the most rapid decrease in the course of starvation.

Effects of Fasting on Blood Sugar Levels in Baby Chicks of Varying Ages

ABSTRACT THE new-born animal is characterized by profound physiological changes as it adapts to its new and more variable environment. Of these adaptations none is perhaps more critical than that to new nutritional sources. Failure to ingest food or to ingest sufficient quantities of the various nutrients may result in death of the new-born animal after a survival time much shorter than that of the adult under similar conditions. In complete starvation death presumably results ultimately because of insufficient quantities of some one substance for essential metabolic activities. In this respect influence of previous dietary intake on the course of starvation between individuals would be minimal in new-born animals. In new-born pigs there is evidence that the critical substance in starvation death is glucose (Graham, Sampson and Hester, 1941). In the fasting animal carbohydrate stores initially present are rapidly exhausted; then the primary source of blood glucose is hepatic gluconeogenesis. It . . .

Premortal Enlargement of Mitochondria in Rat Liver Cells Caused by Starvation

1. In a series of experiments on starvation and subsequent alimentation, changes of mitochondria of rat liver cells were examined in relation to the types of hepatic cytoplasm as regards the distribution of ribonucleic acid and some other properties of the liver.2. At the agonal stage resulting from starvation, mitochondria were found always to be greatly enlarged in hepatic cells which had undergone condsiderable diminution in size and in which the cytoplasmic ribonuleic acid had been remarkably reduced. This is accompanied by only slight decrease of specific gravity of the liver tissue, which suggest that this type of mitochondrial or cytochondrial enlargement is not caused by a simple osmotic swelling.3. The alteration of mitochondria and cytochondria in the course of starvation was considered under the light of a hypothesis that mitochondria fixed in ordinary fixatives take the figure to be identified as cytochondria.4. A remarkable change of the free amino acid pattern obtained preliminarily by paper chromatography was found to accompany the premortal enlargement of mitochondria caused by starvation.The writer expresses his hearty thanks to Dr. Y. Saito, late Miss H. Kawamata, and Mr. T. E. Y ukimura, Medico-Biological Institute, Minophagen Pharmaceutical Co., for their valuable assistance and criticisms unsparingly given him.

THE EFFECT OF GROWTH AND NUTRITION ON MITOCHONDRIA IN LIVER CELLS OF FUNDULUS HETEROCLITUS

In a recent study on Triturus pyrrhogaster (McCurdy, 1939) I found that starvation and re-feeding tend to produce definite changes in the mitochondrial picture of the liver cells. In the course of starvation, the elongated mitochondria which predominate in well-fed animals gradually give way to granular mitochondria, and these latter finally become predominant. When the procedure is reversed and starved animals are re-fed, the mitochondria change in the opposite direction, from granular to elongated. These mitochondrial changes, however, though they clearly depend upon digestive activity and degree of starvation in general, are more closely related to the amounts of fat and glycogen in the liver itself. It can be stated as a rule that in the liver cells of Triturus increase in the fat and glycogen content is accompanied by an increase in the proportion of elongated mitochondria, and decrease in the fat and glycogen content is accompanied by an increase in the proportion of granular mitochondria. There is thus an important relationship between the nutrition of cells and the form of their mitochondria. The present study is concerned with two questions: (1) Does a similar relationship between mitochondrial form and the amount of storage products exist in a different species? (2) Does growth affect the morphology of the mitochondria?