Voluntary palliated starvation : A lawful and ethical way to die?

Increasingly, individuals want control over their own destiny. This includes the way in which they die and the timing of their death. The desire for self-determination at the end of life is one of the drivers for the ever-increasing number of jurisdictions overseas that are legalising voluntary euthanasia and/or assisted suicide, and for the continuous attempts to reform state and territory law in Australia. Despite public support for law reform in this field, legislative change in Australia is unlikely in the near future given the current political landscape. We argue that there may be another solution which provides competent adults with control over their death and to have any pain and symptoms managed by doctors, but which is currently lawful and consistent with prevailing ethical principles. ‘Voluntary palliated starvation’ refers to the process which occurs when a competent individual chooses to stop eating and drinking, and receives palliative care to address pain, suffering and symptoms that may be experienced by the individual as he or she approaches death. In this article, we argue that, at least in some circumstances, such a death would be lawful for the individual and doctors involved, and consistent with principles of medical ethics.

Survival and reproduction of Tribolium castaneum (Herbst), Rhyzopertha dominica (F.) and Sitophilus oryzae (L.) following periods of starvation

This study determined the starvation tolerance of Tribolium castaneum (Herbst), Rhyzopertha dominica (F.) and Sitophilus oryzae (L.) in terms of both adult survival and reproduction, the impact of starvation on reproduction not having been studied before. Experiments were conducted at 30°C and 55% or 70% r.h. using a laboratory strain and a field strain of each species. The number of progeny was a better indicator of the impact of starvation on a species than adult survival. Tribolium castaneum was the most tolerant species, requiring up to 35 d starvation before no progeny were produced. Rhyzopertha dominica and S. oryzae required up to 8 d starvation before no progeny were produced. The results suggest that hygiene will have a greater impact on populations of S. oryzae and R. dominica than T. castaneum.

Influence of starvation and clofibrate administration on oxidative phosphorylation by rat liver mitochondria

Whole cells, homogenates and mitochondrial obtained from the livers of albino rats which were starved for 6 days or more showed a 50% decrease in oxidative activity. The decrease could be corrected by the addition of cytochrome c in vitro. The phosphorylative activity of mitochondria remained unaffected. The decrease in oxidative rate was not observed when starving animals were given the anti-hypercholesterolaemic drug clofibrate. The total cellular concentration of cytochrome c was not affected by starvation. However, the concentration of the pigment in hepatic mitochondria isolated from starving animals was less than half that in normal mitochondria. Clofibrate-treated animals did not show a decreased concentration of cytochrome c in hepatic mitochondria. Mitochondria isolated from starving animals, though deficient in cytochrome c, did not show any decrease in succinate dehydrogenase activity or in the rate of substrate-dependent reduction of potassium ferricyanide or attendant phosphorylation. In coupled mitochondria, ferricyanide may not accept electrons from the cytochrome c in the respiratory chain. Starvation decreases the concentration of high-affinity binding sites for cytochrome c on the mitochondrial membrane. The dissociation constant increases in magnitude.

Do Phosphine Resistance Genes Influence Movement and Dispersal Under Starvation?

Phosphine resistance alleles might be expected to negatively affect energy demanding activities such as walking and flying, because of the inverse relationship between phosphine resistance and respiration. We used an activity monitoring system to quantify walking of Rhyzopertha dominica (F.) and a flight chamber to estimate their propensity for flight initiation. No significant difference in the duration of walking was observed between the strongly resistant, weakly resistant, and susceptible strains of R. dominica we tested, and females walked significantly more than males regardless of genotype. The walking activity monitor revealed no pattern of movement across the day and no particular time of peak activity despite reports of peak activity of R. dominica and Tribolium castaneum (Herbst) under field conditions during dawn and dusk. Flight initiation was significantly higher for all strains at 28 degrees C and 55% relative humidity than at 25, 30, 32, and 35 degrees C in the first 24 h of placing beetles in the flight chamber. Food deprivation and genotype had no significant effect on flight initiation. Our results suggest that known resistance alleles in R. dominica do not affect insect mobility and should therefore not inhibit the dispersal of resistant insects in the field.

Transcriptional switching in Escherichia coli during stress and starvation by modulation of Sigma 70 activity

During active growth of Escherichia coli, majority of the transcriptional activity is carried out by the housekeeping sigma factor (Sigma 70), whose association with core RNAP is generally favoured because of its higher intracellular level and higher affinity to core RNAP. In order to facilitate transcription by alternative sigma factors during nutrient starvation, the bacterial cell uses multiple strategies by which the transcriptional ability of Sigma 70 is diminished in a reversible manner. The facilitators of shifting the balance in favour of alternative sigma factors happen to be as diverse as a small molecule (p)ppGpp (represents ppGpp or pppGpp), proteins (DksA, Rsd) and a species of RNA (6S RNA). Although 6S RNA and (p)ppGpp were known in literature for a long time, their role in transcriptional switching has been understood only in recent years. With themelucidation of function of DksA, a new dimension has been added to the phenomenon of stringent response. As the final outcome of actions of (p)ppGpp, DksA, 6S RNA and Rsd is similar, there is a need to analyse hese mechanisms in a collective manner. We review the recent trends in understanding the regulation of Sigma 70 by (p)ppGpp, DksA, Rsd and 6S RNA and present a case for evolving a unified model of RNAP redistribution during starvation by modulation of Sigma 70 activity in E. coli.

A full-length bifunctional protein involved in c-di-GMP turnover is required for long-term survival under nutrient starvation in Mycobacterium smegmatis

The bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP) plays an important role in a variety of cellular functions, including biofilm formation, alterations in the cell surface, host colonization and regulation of bacterial flagellar motility, which enable bacteria to survive changing environmental conditions. The cellular level of c-di-GMP is regulated by a balance between opposing activities of diguanylate cyclases (DGCs) and cognate phosphodiesterases (PDE-As). Here, we report the presence and importance of a protein, MSDGC-1 (an orthologue of Rv1354c in Mycobacterium tuberculosis), involved in c-di-GMP turnover in Mycobacterium smegmatis. MSDGC-1 is a multidomain protein, having GAF, GGDEF and EAL domains arranged in tandem, and exhibits both c-di-GMP synthesis and degradation activities. Most other proteins containing GGDEF and EAL domains have been demonstrated to have either DGC or PDE-A activity. Unlike other bacteria, which harbour several copies of the protein involved in c-di-GMP turnover, M. smegmatis has a single genomic copy, deletion of which severely affects long-term survival under conditions of nutrient starvation. Overexpression of MSDGC-1 alters the colony morphology and growth profile of M. smegmatis. In order to gain insights into the regulation of the c-di-GMP level, we cloned individual domains and tested their activities. We observed a loss of activity in the separated domains, indicating the importance of full-length MSDGC-1 for controlling bifunctionality.

Identification and characterization of starvation induced msdgc-1 promoter involved in the c-di-GMP turnover

C-di-GMP Bis-(3'-5')-cyclic-dimeric-guanosine monophosphate], a second messenger is involved in intracellular communication in the bacterial species. As a result several multi-cellular behaviors in both Gram-positive and Gram-negative bacteria are directly linked to the intracellular level of c-di-GMP. The cellular concentration of c-di-GMP is maintained by two opposing activities, diguanylate cyclase (DGC) and phosphodiesterase (PDE-A). In Mycobacterium smegmatis, a single bifunctional protein MSDGC-1 is responsible for the cellular concentration of c-di-GMP. A better understanding of the regulation of c-di-GMP at the genetic level is necessary to control the function of above two activities. In this work, we have characterized the promoter element present in msdgc-1 along with the + 1 transcription start site and identified the sigma factors that regulate the transcription of msdgc-1. Interestingly, msdgc-1 utilizes SigA during the initial phase of growth, whereas near the stationary phase SigB containing RNA polymerase takes over the expression of msdgc-1. We report here that the promoter activity of msdgc-1 increases during starvation or depletion of carbon source like glucose or glycerol. When msdgc-1 is deleted, the numbers of viable cells are similar to 10 times higher in the stationary phase in comparison to that of the wild type. We propose here that msdgc-1 is involved in the regulation of cell population density. (C) 2013 Elsevier B.V. All rights reserved.

SUB1 Plays a Negative Role during Starvation Induced Sporulation Program in Saccharomyces cerevisiae

Saccharomyces cerevisiae Sub1 is involved in several cellular processes such as, transcription initiation, elongation, mRNA processing and DNA repair. It has also been reported to provide cellular resistance during conditions of oxidative DNA damage and osmotic stress. Here, we report a novel role of SUB1 during starvation stress-induced sporulation, which leads to meiosis and spore formation in diploid yeast cells. Deletion of SUB1 gene significantly increased sporulation efficiency as compared to the wild-type cells in S288c genetic background. Whereas, the sporulation functions of the sub1(Y66A) missense mutant were similar to Sub1. SUB1 transcript and protein levels are downregulated during sporulation, in highly synchronized and sporulation proficient wild-type SK1 cells. The changes in Sub1 levels during sporulation cascade correlate with the induction of middle sporulation gene expression. Deletion of SUB1 increased middle sporulation gene transcript levels with no effect on their induction kinetics. In wild-type cells, Sub1 associates with chromatin at these loci in a temporal pattern that correlates with their enhanced gene expression seen in sub1. cells. We show that SUB1 genetically interacts with HOS2, which led us to speculate that Sub1 might function with Set3 repressor complex during sporulation. Positive Cofactor 4, human homolog of Sub1, complemented the sub1. sporulation phenotype, suggesting conservation of function. Taken together, our results suggest that SUB1 acts as a negative regulator of sporulation.

Peptide-utilizing carbon starvation gene yjiY is required for flagella-mediated infection caused by Salmonella

Peptide metabolism forms an important part of the metabolic network of Salmonella and to acquire these peptides the pathogen possesses a number of peptide transporters. Whilst various peptide transporters known in Salmonella are well studied, very little is known about the carbon starvation (cst) genes cstA and yjiY, which are also predicted to be involved in peptide metabolism. We investigated the role of these genes in the metabolism and pathogenesis of Salmonella, and demonstrated for the first time, to the best of our knowledge, that cst genes actually participate in transport of specific peptides in Salmonella. Furthermore, we established that the carbon starvation gene yjiY affects the expression of flagella, leading to poor adhesion of the bacterium to host cells. In contrast to the previously reported role of cstA in virulence of Salmonella in Caenorhabditis elegans, we showed that yjiY is required for successful colonization of Salmonella in the mouse gut. Thus, cst genes not only contribute to the metabolism of Salmonella, but also influence its virulence.

Peptide-utilizing carbon starvation gene yjiY is required for flagella-mediated infection caused by Salmonella

Peptide metabolism forms an important part of the metabolic network of Salmonella and to acquire these peptides the pathogen possesses a number of peptide transporters. Whilst various peptide transporters known in Salmonella are well studied, very little is known about the carbon starvation (cst) genes cstA and yjiY, which are also predicted to be involved in peptide metabolism. We investigated the role of these genes in the metabolism and pathogenesis of Salmonella, and demonstrated for the first time, to the best of our knowledge, that cst genes actually participate in transport of specific peptides in Salmonella. Furthermore, we established that the carbon starvation gene yjiY affects the expression of flagella, leading to poor adhesion of the bacterium to host cells. In contrast to the previously reported role of cstA in virulence of Salmonella in Caenorhabditis elegans, we showed that yjiY is required for successful colonization of Salmonella in the mouse gut. Thus, cst genes not only contribute to the metabolism of Salmonella, but also influence its virulence.

Alternating Starvation Of Dislocations During Plastic Yielding In Metallic Nanowires

Using molecular dynamics simulations, we show that the mechanical deformation behaviors of single-crystalline nickel nanowires are quite different from their bulk counterparts. Correlation between the obtained stress-strain curves and the visualized defect evolution during deformation processes clearly demonstrates that a sequence of complex dislocation slip events results in a state of dislocation starvation, involving the nucleation and propagation of dislocations until they finally escape from the wires, so that the wires deform elastically until new dislocations are generated. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Influence of starvation on selected temperatures in the young of bream, roach and perch [Translation from: Informatsionnyi Byulleten Biologiya Vnutrennikh Vod No.50, 45-47, 1981]

Works devoted to the influence of starvation on temperature selection by fishes are few and their conclusions are contradictory. This study determined the influence of brief, up to 14 days, starvation on temperature selection by young fishes. The experiments were carried out in August-September 1976 on fingerling bream (Abramis brama L.), roach (Rutilus rutilus L.) and perch (Perca fluviatilis L.) with body lengths of 3-5 cm and weight 0.5-1.2 g. The young fish were caught in the littoral by seine-nets or small drag-nets. Immediately after catching the fish they were put in acclimatization boxes. The period of acclimatization did not exceed 2 days for bream and roach at a temperature of 20 °C and 6 days for perch at 17 °C. Before the start of the experiment and for the first 10 days of the experiment the fish were fed with oligochaetes, earthworms and daphnia, after that feeding discontinued. At the end of a 10-14 day period the giving of food was resumed. The study concludes that the experiments have shown that in the summer season the factor of starvation significantly changes the reaction to the gradient of temperature in young cyprihids - roach and bream.

Effects of starvation on energy density of juvenile chum salmon (Oncorhynchus keta) captured in marine waters of Southeastern Alaska

We conducted laboratory starvation experiments on juvenile chum salmon (Oncorhynchus keta) captured in the neritic marine waters of northern Southeast Alaska in June and July 2003. Temporal changes in fish energy density (whole body energy content [WBEC], cal/g dry weight), percent moisture content, wet weight (g), length (mm), and size-related condition residuals were measured in the laboratory and were then compared to long-term field data. Laboratory water temperatures and salinities averaged 9°C and 32 psu in both months. Trends in response variables were similar for both experimental groups, although sampling intervals were limited in July because fewer fish were available (n= 54) than in June (n=101). Overall, for June (45-d experimental period, 9 intervals), WBEC, wet weight, and condition residuals decreased and percent moisture content increased, whereas fork length did not change. For July (20-d experimental period, 5 intervals), WBEC and condition residuals decreased, percent moisture content and fork length increased, and wet weight did not change. WBEC, percent moisture content, and condition residuals fell outside the norm of longterm data ranges within 10–15 days of starvation, and may be more useful than fork length and wet weight for detecting fish condition responses to suboptimal environments.

Effect of starvation on the biochemical composition of Clarias batrachus (Linn.)

Marked changes were observed in different chemical constituents of C. batrachus during starvation. The N and protein fractions showed a definite pattern of variations. The highest values of these were recorded on 10th day of starvation and thereafter values declined gradually. On the other hand, the acid soluble phosphorus exhibited a reverse trend, increasing gradually from the first to the 30th day of starvation. These changes have been attributed mainly to the energy and metabolic demands of the starving fish.

Influence of sex, spawning, starvation and water temperature on fatty acid composition in Tilapia mossambica

The influence of sex, spawning, starvation and water temperature on the fatty acid composition of Tilapia mossambica has been studied. Tilapia egg lipid was found to have unusually high percentage of C sub(22:6) fatty acids (9.09%) compared to body and intestinal lipids. The C sub(16:1) acid was much less in the egg lipids (3.5%) whereas it was 11% in the body lipids. There was no significant difference in the fatty acid composition of body and intestinal lipids of male and female tilapia. Starvation caused the presence of high content of lower fatty acids (C sub(6), C sub(8), C sub(30), C sub(12) and C sub(33)) in the body lipids. Water temperature also influenced the fatty acid composition of Tilapia; the difference was more significant in body lipids than in intestinal lipids.