The effect of sulfur-containing compounds on stress resistance of Drosophila melanogaster

We have studied the resistance of D. melanogaster imago, Oregon-R stock, reared on the culture medium, supplied either with methionine (1 mg/ml), or with sodium thiosulphate (0.05 mol/l or 0.1 mol/l), to heat (thermal) and alimentary stress. Also we have analyzed the effect of these substances addition to the medium on fertility and pupa lethality of D. melanogaster. A significant increase of resistance to heat stress was shown in flies reared on the culture medium supplied with methionine. Percent of individuals survived after heat stress increased by 35.5%. Imago survival, in the conditions of alimentary deprivation, increased; in this group average life span increased for 3.7 hours, maximal – for 7.5 hours. Fertility of drosophila reared on the medium with addition of methionine increased; number of pupas obtained from one female was more, than in control by 44%. Pupa lethality in this group decreased in three times. Resistance to heat stress of flies reared on the medium with addition of sodium thiosulphate (0.05 mol/l) increased. Number of individuals survived after heat stress was more, than in control by 10%. However, resistance to alimentary deprivation decreased. Their average life span was less for 3.2 hour, than in the control group, and maximal life span was less for 5.4 hour. Resistance to heat stress of flies reared on the medium supplemented with 0.1 mol/l sodium thiosulphate decreased. Percent of individuals survived after heat stress was twice less. Average life span and maximal life span in the conditions of alimentary deprivation increased by 3.4 hours and by 5.5 hours respectively. Fertility of flies developed in the medium with sodium thiosulfate (0.05 mol/l) supplement increased by 48 %, while same index for those consumed sodium thiosulfate 0.1 mol/l had a clear tendency to reduction by 33%. Pupa lethality in both groups consumed sodium thiosulphate (0.05 mol/l and 0.1 mol/l) decreased by 28% and 35% respectively. Thus, methionine consumption by larvae of D. melanogaster promotes resistance to stress and fertility of Oregon-R stock. The effect of sodium thiosulphate on drosophila fitness indexes studied depends on its concentration in the culture medium.

Life cycles and somatic production of hyperiids in the Okhotsk and Bering Seas

Hyperiid species Themisto pacifica , T. libellula , and Primno macropa are widespread in the Far-Eastern Seas. They are an important element of trophic web in pelagic communities of these seas. Their food spectra are very broad and include copepods, euphausiids, arrowworms, and fish larvae. On the other hand, the hyperiids play an important role in the diet of large-sized marine organisms as walleye pollock Theragra chalcogramma , mackerels Scomber japonicus , Pleurogrammus monopterygius , and Pleurogrammus azonus , and japanese squid Todarodes pacificus . Life cycles and production of these hyperiid species are described on the base of samples collected in complex surveys conducted by Pacific Fish. Res. Center (TINRO) in the Okhotsk Sea and the western Bering Sea in 1984-2011. All three species have similar life history though the maximal life span is 2 years for T. pacifica and T. libellula but 3 years for Primno macropa . They spawn twice in their life in the period from May to October with the peak in July. Their weight increments also increase twice, usually when their size is 7-10 and 10-12 mm for T. pacifica and P. macropa and 10-15 and 20-30 mm for T. libellula . The average specific daily production of hyperiids in the Okhotsk Sea is estimated as 0.0410 for T. pacifica , 0.0273 for T. libellula , and 0.0101 for P. macropa ; but in the western Bering Sea - as 0.0492 for T. pacifica , 0.0361 for T. libellula , and 0.0094 for P. macropa . The most favorable feeding grounds for hyperiids are located at Kuril Islands, at West Kamchatka, and in the Anadyr Bay. Their summary annual production is estimated as 30.235 mln t in the Okhotsk Sea and 21.370 mln t in the western Bering Sea.

Vitamin E at high doses improves survival, neurological performance, and brain mitochondrial function in aging male mice

Male mice receiving vitamin E (5.0 g α-tocopherol acetate/kg of food) from 28 wk of age showed a 40% increased median life span, from 61 ± 4 wk to 85 ± 4 wk, and 17% increased maximal life span, whereas female mice equally supplemented exhibited only 14% increased median life span. The α-tocopherol content of brain and liver was 2.5-times and 7-times increased in male mice, respectively. Vitamin E-supplemented male mice showed a better performance in the tightrope (neuromuscular function) and the T-maze (exploratory activity) tests with improvements of 9–24% at 52 wk and of 28–45% at 78 wk. The rates of electron transfer in brain mitochondria, determined as state 3 oxygen uptake and as NADH-cytochrome c reductase and cytochrome oxidase activities, were 16–25% and 35–38% diminished at 52–78 wk. These losses of mitochondrial function were ameliorated by vitamin E supplementation by 37–56% and by 60–66% at the two time points considered. The activities of mitochondrial nitric oxide synthase and Mn-SOD decreased 28–67% upon aging and these effects were partially (41–68%) prevented by vitamin E treatment. Liver mitochondrial activities showed similar effects of aging and of vitamin E supplementation, although less marked. Brain mitochondrial enzymatic activities correlated negatively with the mitochondrial content of protein and lipid oxidation products ( r2 = 0.58–0.99, P < 0.01), and the rates of respiration and of complex I and IV activities correlated positively ( r2 = 0.74–0.80, P < 0.01) with success in the behavioral tests and with maximal life span.

Adult-Onset Growth Hormone and Insulin-Like Growth Factor I Deficiency Reduces Neoplastic Disease, Modifies Age-Related Pathology, and Increases Life Span

Disruption of the insulin/IGF-I pathway increases life span in invertebrates. However, effects of decreased IGF-I signaling in mammalian models remain controversial. Using a rodent model with a specific and limited deficiency of GH and IGF-I, we report that GH and IGF-I deficiency throughout life [GH deficiency (GHD)] has no effect on life span compared with normal, heterozygous animals. However, treatment of GHD animals with GH from 4–14 wk of age [adult-onset (AO) GHD] increased median and maximal life span by 14% and 12%, respectively. Analysis of end-of-life pathology indicated that deficiency of these hormones decreased tumor incidence in GHD and AO-GHD animals (18 and 30%, respectively) compared with heterozygous animals and decreased the severity of, and eliminated deaths from, chronic nephropathy. Total disease burden was reduced by 24% in GHD and 16% in AO-GHD animals. Interestingly, the incidence of intracranial hemorrhage increased by 154 and 198% in GHD and AO-GHD animals, respectively, compared with heterozygous animals. Deaths from intracranial hemorrhage in AO-GHD animals were delayed by 14 wk accounting for the increased life span compared with GHD animals. The presence of GH and IGF-I was necessary to maximize reproductive fitness and growth of offspring early in life and to maintain cognitive function and prevent cartilage degeneration later in life. The diverse effects of GH and IGF-I are consistent with a model of antagonistic pleiotropy and suggest that, in response to a deficiency of these hormones, increased life span is derived at the risk of functional impairments and tissue degeneration.

Saccharomyces cerevisiae SSD1-VConfers Longevity by a Sir2p-Independent Mechanism

The SSD1 gene of Saccharomyces cerevisiae is a polymorphic locus that affects diverse cellular processes including cell integrity, cell cycle progression, and growth at high temperature. We show here that the SSD1-V allele is necessary for cells to achieve extremely long life span. Furthermore, addition of SSD1-V to cells can increase longevity independently of SIR2, although SIR2 is necessary for SSD1-V cells to attain maximal life span. Past studies of yeast aging have been performed in short-lived ssd1-d strain backgrounds. We propose that SSD1-V defines a previously undescribed pathway affecting cellular longevity and suggest that future studies on longevity-promoting genes should be carried out in long-lived SSD1-V strains.