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PubMedDate not supplied

Suppression of experimental autoimmune uveoretinitis by dietary calorie restriction.

To investigate the inhibitory effect of dietary calorie restriction on experimental autoimmune uveoretinitis (EAU) in rats, and its mechanism. Lewis rats were maintained on a 50% calorie-restricted diet for 2 months or 6 months. The control group was maintained on a 90% ad libitum intake for the same length of time. Experimental autoimmune uveoretinitis was elicited in both groups by immunization with an inter-photoreceptor retinoid-binding protein or its peptide. Rats in both groups were examined clinically, histopathologically, and immunologically. The severity of EAU was milder in the restricted diet group than in the control group. In EAU rats, production of interferon-gamma (IFN-gamma) in eyes and of IFN-gamma and tumor necrosis factor-alpha in draining lymph node cells was significantly lower in the restricted diet group than in the control group. Our results indicate that a calorie-restricted diet suppresses the development of EAU. The suppressed Th1-dependent immunological response is one of the reasons for the mildness of EAU in the calorie-restricted diet group of rats.

Animals↗

PubMed1983

Effect of calcium restriction on renal excretion of oxalate and the probability of stones in the various pathophysiological groups with calcium stones.

To evaluate the adequacy of simple calcium restriction for patients with idiopathic calcium stones the effect of 5 days of calcium restriction without oxalate restriction on renal excretion of calcium and oxalate, and the corresponding probability of stones were assessed in 50 controls and 48 patients. Renal excretion of calcium decreased and that of oxalate increased significantly in all groups but the importance of the changes was critically dependent upon the underlying pathophysiological condition. The probability of stones decreased only in patients with absorptive hypercalciuria type II owing to the usual excessive calcium intake and increased in those with absorptive hypercalciuria type I and renal hypercalciuria, which are associated with true hyperabsorption of calcium and represent the 2 forms of idiopathic hypercalciuria. We believe that simple calcium restriction is beneficial for patients with idiopathic calculi only when the hypercalciuria is caused by exaggerated intake of calcium, since it increases the probability of stones in patients with idiopathic hypercalciuria. Calcium restriction always is associated with an increase in oxalate excretion, suggesting that simultaneous oxalate restriction should be added in all cases to decrease the probability of stones.

Adult↗

PubMed2000

Internal jugular vein blood flow in normal and growth-restricted fetuses.

OBJECTIVE: To assess internal jugular vein blood flow patterns during the second half of pregnancy in normal and growth-restricted fetuses. METHODS: We did Doppler ultrasound studies of internal jugular veins and the inferior vena cavas longitudinally on 21 normal singleton fetuses from 20 weeks to term, and on eight growth-restricted fetuses with absent end-diastolic flow at the umbilical artery (UA). The three components of the venous flow velocity waveforms were used to calculate peak velocity ratio: Peak systolic velocity (S wave) minus reverse peak velocity (R wave) divided by peak velocity during early diastole (D wave) and velocity time integral ratio: systolic velocity time integral minus reverse velocity time integral divided by velocity time integral during early diastole. Statistical analysis of longitudinal measurements used K-related samples Friedman test; groups were compared with Mann-Whitney U test and chi(2) test. RESULTS: In normal fetuses we found significant increases in peak velocity ratio and velocity time integral ratio of internal jugular veins and the inferior vena cavas throughout gestation. The mean +/- standard deviation (SD) of the internal jugular veins peak velocity ratio (1.12 +/- 0.4 versus 1.46 +/- 0.15, P <.05) and velocity time integral ratio (1.1 +/- 0.2 versus 1.55 +/- 0.17, P <.05) were significantly lower in growth-restricted fetuses compared with normal fetuses at 28-32 weeks' gestation but inferior vena cava indices were not. None of the eight growth-restricted fetuses had umbilical venous pulsations or changes in inferior vena cava or ductus venosus blood flow patterns. All had arterial pH above 7.15 at birth. CONCLUSION: Growth-restricted fetuses with absent end-diastolic velocity in the UA have changes in internal jugular vein blood flow patterns that probably indicate increased cerebral blood flow, more evidence of redistribution of blood flow in growth-restricted fetuses that can be used to maintain them.

Adult↗

PubMed2002

A new animal model of binge eating: key synergistic role of past caloric restriction and stress.

Dieting and stress are important in the etiology and maintenance of eating disorders, and dieting strongly predicts stress-induced overeating in humans. We hypothesized that caloric restriction and stress interact in a unique manner to promote binge eating. To test this hypothesis, a group of young female rats were cycled through a restriction period (4 days of 66% of control food intake) followed by 6 days of free feeding prior to being stressed by acute foot shock. After three of these cycles, the food intake of rats exposed only to restriction (R), or only to stress (S), did not differ from controls. However, R+S rats that were restricted and refed, despite normal body weight and food intake after free feeding, engaged in a powerful bout of hyperphagia when stressed (Experiment 1). The R + S effect was replicated in an older group of rats (Experiment 2). The hyperphagia was characteristically binge-like, it constituted a 40% selective increase in highly palatable (HP) food (P < .001) over a discrete period of time (within 24 h post-stress), and reflected feeding for reward (higher HP:chow ratio) over metabolic need as occurred after restriction (higher chow:HP ratio). Subsequent experiments revealed that binge eating did not occur if only chow was available (Experiment 3) or if restriction-refeeding (R-R) did not proximally precede stress (Experiment 4). Experiment 5 revealed that a history of R-R cycles followed by only one stress episode was sufficient to increase intake to 53% above controls as early as 2 h after stress (P < .001). This animal model of binge eating should facilitate investigations into the neurochemical changes induced by dieting and environmental stress to produce disordered eating and provide a preclinical tool to test preventive strategies and treatments more relevant to bulimia nervosa, multiple cases of binge eating disorder (BED) and binge-purge type anorexia nervosa.

Animals↗

PubMed1997

Female sexual behavior is inhibited by short- and long-term food restriction.

In female musk shrews, sexual receptivity is not restricted to the periovulatory period. Several copulatory bouts that occur over a number of days are required to induce the first ovulation. We tested the hypothesis that food restriction would have a minimal impact on female musk shrew sexual behavior because mating behavior may be uncoupled from ovulation in this species. Three testing conditions were used. In the first study, food-restricted females were maintained at their weaning day weight for 17 days. Food restriction resulted in a significant reduction in the number of females that allowed males to mount, intromit, or ejaculate compared with ad lib-fed controls. In the second experiment, sexually experienced females that were food-restricted for 2 weeks also displayed reduced sexual behavior compared to that in ad lib-fed controls. In the last study, we examined the effects of short-term food fluctuations on sexual behavior. Females food-restricted for 48 h showed reduced mating behavior compared to that in ad lib-fed controls. This was reversed after 24 h of refeeding. These studies show that, even under conditions where copulation does not lead to pregnancy, small reductions in food availability can inhibit female sexual behavior.

Animals↗

PubMed1997

Influence of dietary restriction on ionotropic glutamate receptors during aging in C57B1 mice.

The present study was designed to determine whether the memory sparing effects of dietary restriction during aging could be through an effect on ionotropic glutamate receptors. Quantitative autoradiography was performed on 3, 10, and 26 month old mice to examine the density changes of NMDA, AMPA and kainate binding sites in aging animals. Spatial memory performance was also tested in these mice with the use of the Morris water maze. The 10 and 26 month olds were either ad libitum-fed or diet-restricted (60% of ad libitum-fed calories). Ad libitum-fed, 26 month old mice had significant decreases in NMDA-displaceable [3H]glutamate in all ten cortical, two out of seven hippocampal, and two out of four subcortical regions, as compared to 3 month olds. Diet-restricted, 26 month old mice only differed significantly from young in three cortical and two subcortical regions. The aged ad libitum-fed mice exhibited significantly poorer performance in the spatial memory task than all other groups. The diet-restricted 26 month olds only performed significantly worse than 3 month olds and diet-restricted 10 month olds. These results suggest that some of the memory sparing effects of dietary restriction on aged animals may be due to an influence on NMDA receptors.

Aging↗

PubMed1997

Predominance of H-2d- and H-2k-restricted T-cell epitopes in the highly repetitive Plasmodium falciparum antigen Pf332.

Genetic restriction of immune responses to malaria antigens is an important issue for a better comprehension of malaria immunity as well as for development of subunit vaccines. To experimentally define the major histocompatibility complex restriction of immune responses to the highly repetitive Plasmodium falciparum high-molecular-weight antigen Pf332, H-2-congenic mice were immunized with EB200, a recombinant fragment of Pf332 consisting of degenerate repeat motifs. Strong B- and T-cell responses were elicited in H-2d and H-2k mice whereas responses in H-2b, H-2q and H-2s mice were of lower magnitude. The T-cell specificity elicited by EB200 was defined by in vitro proliferative responses to a panel of overlapping peptides spanning EB200. Dominant epitopes were identified for H-2d and H-2k mice, respectively, and an additional epitope was recognized by all five mouse strains. Selected EB200-derived peptides were further investigated for their ability to elicit T-cell help when injected as multiple antigen peptides. Defined H-2d- and H-2k-restricted T-cell epitopes generated high antibody levels in the respective mouse strains, as did several peptides lacking defined epitopes indicating the presence of additional H-2d- and H-2k-restricted, cryptic or subdominant T-cell epitopes in EB200. The biased H-2 restriction pattern of T-cell epitopes in Pf332 and, as previously reported, in structurally related repeats in the malaria antigens Pf11.1 and Pf155/RESA may be explained by a shared motif for H-2d and H-2k class II-restricted T-cell epitopes, as revealed by alignment of these sequences.

Amino Acid Sequence↗

PubMed2002

Effects of restricted feeding on the activity of hypothalamic Orexin (OX)-A containing neurons and OX2 receptor mRNA level in the paraventricular nucleus of rats.

We have examined the effects of 3 weeks of food restriction on both the activity of neurons containing hypothalamic orexin (OX)-A and the level of OX receptor type 2 (OX2R) mRNA in the paraventricular nucleus (PVN) of rats. Double immunohistochemistry was used to examine the expression of OX-A and Fos in the lateral hypothalamic area (LHA), and in situ hybridization histochemistry was used to measure levels of OX2R mRNA in the PVN. After the period of restricted feeding, 20-30% of OX-A-containing neurons exhibited Fos-like immunoreactivity (LI). The distribution of OX-A-LI/Fos-LI cells in the food-restricted rats was similar to that observed in glucose-deprived rats after intracerebroventricular (icv) administration of 2-deoxy-D-glucose (2-DG). In addition, 3 weeks of food restriction caused a significant decrease in the expression of the OX2R gene in the parvocellular division of the PVN. These results suggest that the activation of OX-A-containing neurons induced by restricted feeding may be involved in neuroendocrine responses to food restriction.

Animals↗

PubMed2000

Effect of male-to-male aggressiveness and feed-restriction during rearing on sexual behaviour and aggressiveness towards females by male domestic fowl.

This experiment was one part of a larger study investigating problems of aggression towards females by male broiler breeder fowl. To investigate causal mechanisms, we were interested in determining (1) if feed-restriction during rearing affects behaviour towards females at sexual maturity and (2) if aggressiveness towards females is correlated with general levels of aggressiveness. We compared broiler breeder males with commercial laying strain males, which were either fed ad libitum or were feed-restricted during the rearing phase, and with game strain males, bred for fighting. Differences in behaviour were determined by observing males during interactions with small groups of females.Laying strain males did not behave aggressively towards females, whether feed-restricted or fed ad libitum during rearing. Despite genetic selection for fighting ability, game strain males also were not aggressive towards females. Conversely, broiler breeder males displayed significantly higher levels of aggression towards females than did feed-restricted laying strain males (P<0.02). Broiler breeder males were rough with females during mating, whereas laying strain and game strain males were not. Females struggled more frequently during mating attempts by broiler breeder males (P<0.002) and interfered frequently when these males attempted to mate with other females.From our results, we conclude that (1) feed-restriction during rearing has little effect on the sexual and aggressive behaviour of laying strain males at maturity and (2) selection for aggressiveness has not resulted in males which are more aggressive to females. Aggression towards females appears to be a unique problem occurring in broiler breeder male strains and not a function of feed-restriction.

Journal Article↗

PubMed2003

Restricting fluid intake during a single meal did not affect food intake in older adults.

Restricting fluid intake has been shown to decrease ad libitum food intake in animals and young adult humans. The purpose of this study was to determine if restricting fluid intake during a meal affects food intake in older adults. In a crossover counterbalanced design, 24 subjects (11 m, 13 f), 61-95 years, received lunch at a congregate meal site. Identical meals were accompanied by a volume of water equal to either 40% (restricted) or 100% (control) of each subject's usual lunch fluid intake. Pre-meal urine osmolality and specific gravity were used as indicators of hydration status. Weighed food intake was not different between the restricted and control conditions (400 g/2875 kJ and 408 g/2971 kJ, respectively). No significant correlations were found between urine osmolality or specific gravity and food intake, either in response to fluid restriction or per kg body weight. These results suggest that the appetite of healthy free-living older adults is not affected by fluid restriction during a single eating episode.

Aged↗

PubMed1998

Influence of diet restriction and tumor promoter dose on cell proliferation, oxidative DNA damage and rate of papilloma appearance in the mouse skin after initiation with DMBA and promotion with TPA.

The mouse skin tumor initiation-promotion model was used to investigate the protective effect of diet restriction in mechanistic and quantitative terms. A total of five groups of 14 male NMRI mice were initiated with 100 nmol 7,12-dimethylbenz[a]anthracene (DMBA) and promoted twice weekly with 2.5, 1.25, or 0.625 nmol 12-O-tetradecanoylphorbol-13-acetate (TPA). Food intake was ad libitum (all 3 TPA dose levels) or restricted to 70% (high and intermediate TPA dose levels). Time of appearance of the first papilloma was recorded for each mouse. Two weeks later, an osmotic minipump delivering 5-bromo-2'-deoxyuridine (BrdU) was implanted and the mouse was killed after 24 h. Cell proliferation in the epidermis was assessed by immunohistochemistry for BrdU incorporated into DNA. 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in epidermal DNA was determined by HPLC/electrochemical detection. The median latency time (t50) for the appearance of skin papilloma in the high-, intermediate-, and low-dose TPA groups fed ad libitum was 9, 15.5, and 23.5 weeks, respectively. The diet-restricted groups (high and intermediate TPA dose) showed t50 values of 16 and 26 weeks. Therefore, diet restriction to 70% had approximately the same protective effect as reducing the dose of TPA by a factor of two. Both the rate of cell proliferation and the level of 8-OH-dG in the epidermis increased with the dose of TPA. Median values were increased 3- to 4-fold at the highest dose. In controls, but not in TPA-treated animals, diet restriction resulted in a decrease for both markers, by 25 and 40% for the labeling index for cell division and the level of 8-OH-dG, respectively. Both markers showed an inverse relationship with the median papilloma latency time. On an individual basis, the correlation was significant in some groups, but only for the labeling index. The data indicate that protection from the skin tumor-promoting effect of TPA by diet restriction could be based more on a reduction of the rate of cell division than on a reduction of oxidative DNA damage.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2000

Pseudonormal and restrictive filling patterns predict left ventricular dilation and cardiac death after a first myocardial infarction: a serial color M-mode Doppler echocardiographic study.

OBJECTIVES: We sought to assess the prognostic value of left ventricular (LV) filling patterns, as determined by mitral E-wave deceleration time (DT) and color M-mode flow propagation velocity (Vp), on cardiac death and serial changes in LV volumes after a first myocardial infarction (MI). BACKGROUND: Combined assessment of DT and Vp allows separation of the effects of compliance and relaxation on LV filling, thereby allowing identification of pseudonormal filling. This may be valuable after MI, where abnormal LV filling is frequently present. METHODS: Echocardiography was performed within 24 h, five days and one and three months after MI in 125 unselected consecutive patients. Normal filling was defined as DT 140 to 240 ms and Vp > or =45 cm/s; impaired relaxation as DT > or =240 ms; pseudonormal filling as DT 140 to 240 ms and Vp <45 cm/s; and restrictive filling as DT <140 ms. RESULTS: Left ventricular filling was normal in 38 patients; impaired relaxation in 38; pseudonormal in 23; and restrictive in 26. End-systolic and end-diastolic volume indexes were significantly increased during the first three months after MI in patients with pseudonormal or restrictive filling (37+/-15 vs. 47+/-19 ml/m2, p<0.0005 and 71+/-20 vs. 88+/-24 ml/m2, p<0.0005, respectively). During a follow-up period of 12+/-7 months, 33 patients died. Mortality was significantly higher in patients with impaired relaxation (p = 0.02), pseudonormal filling (p<0.00005) and restrictive filling (p<0.00005), compared with patients with normal filling. On Cox analysis, restrictive filling (p = 0.003), pseudonormal filling (p = 0.006) and Killip class > or =II (p = 0.008) independently predicted cardiac death, compared with clinical and echocardiographic variables. CONCLUSIONS: Pseudonormal or restrictive filling patterns are related to progressive LV dilation and predict cardiac death after a first MI.

Aged↗

PubMed2002

Influence of aging and long-term caloric restriction on oxygen radical generation and oxidative DNA damage in rat liver mitochondria.

The effect of long-term caloric restriction and aging on the rates of mitochondrial H2O2 production and oxygen consumption as well as on oxidative damage to nuclear (nDNA) and mitochondrial DNA (mtDNA) was studied in rat liver tissue. Long-term caloric restriction significantly decreased H2O2 production of rat liver mitochondria (47% reduction) and significantly reduced oxidative damage to mtDNA (46% reduction) with no changes in nDNA. The decrease in ROS production was located at complex I because it only took place with complex I-linked substrates (pyruvate/malate) but not with complex II-linked substrates (succinate). The mechanism responsible for that decrease in ROS production was not a decrease in mitochondrial oxygen consumption because it did not change after long-term restriction. Instead, the caloric restricted mitochondria released less ROS per unit electron flow, due to a decrease in the reduction degree of the complex I generator. On the other hand, increased ROS production with aging in state 3 was observed in succinate-supplemented mitochondria because old control animals were unable to suppress H2O2 production during the energy transition from state 4 to state 3. The levels of 8-oxodG in mtDNA increased with age in old animals and this increase was abolished by caloric restriction. These results support the idea that caloric restriction reduces the aging rate at least in part by decreasing the rate of mitochondrial ROS production and so, the rate of oxidative attack to biological macromolecules like mtDNA.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1997

Increased transcription of the astrocyte gene GFAP during middle-age is attenuated by food restriction: implications for the role of oxidative stress.

Glial fibrillary acidic protein (GFAP), an intermediate filament of astrocytes, shows increased expression during aging. Because we found that chronic food restriction retards the increase of GFAP mRNA in aging rats and because food restriction decreases the load of oxidized proteins and lipids in association with increased life span, we investigated the regulation of GFAP during oxidative stress and aging. First, we showed that food restriction decreased the transcription of GFAP in aging rats. This result generalizes effects of food restriction on age changes of transcription; whether transcription decreases during aging as in hepatic genes, or increases during aging as in astrocytic GFAP, food restriction attenuates the age change. Moreover, food restriction decreased microglial activation during aging, which suggested the hypothesis that GFAP expression is sensitive to oxidative stress. Because GFAP transcription in cultured glia is increased by oxidative stress in response to hydrogen peroxide and cysteamine whether or not microglia were present, we conclude that responses of GFAP to oxidative stress in astrocytes do not depend on microglial activation. The results implicate oxidative stress in the increased expression of GFAP during aging, but also in responses to brain injury.

Aging↗

PubMed1998

Dietary restriction augments protection against induction of the mitochondrial permeability transition.

Exposure to oxidants or phosphate, especially in the presence of calcium, has been long known to lead to mitochondrial structural alteration and damage. In the past 15 years, it has become increasingly appreciated that this damage is often the result of a cyclosporin A-sensitive event, the "permeability transition" (PT). Using liver mitochondria isolated from male Fischer 344 rats of 6-24 months of age, we now present evidence that long-term, life-prolonging, dietary restriction regimens greatly delay induction of a PT following challenge. Dietary restriction slowed induction by 25 microM calcium, or by calcium in conjunction with the strong oxidant t-butyl hydroperoxide, by approximately 50%. The increased resistance to PT induction was maintained through 24 months of age. Dietary restriction also protected against t-butyl hydroperoxide in the presence of high calcium challenges (250 microM), although the extent of this protection was age-dependent. Induction by 2.5 mM phosphate alone was blocked in most 6-month-old dietary restricted animals and was slowed by 50-100% in animals 12-24 months of age. Susceptibility to 25 microM calcium in conjunction with phosphate varied in an age-dependent manner, ranging from 4-12 times slower in the dietary restricted animals than in their ad lib fed counterparts. Together, these data provide evidence that the factors regulating PT induction are affected by long-term physiological and environmental conditions such as age and diet. The observed effects represent one of the largest recognized dietary restriction-mediated increases in a parameter related to antioxidant defenses. These data also suggest that the endogenous defense systems that protect mitochondria from calcium in conjunction with inorganic phosphate differ from those that protect against calcium in conjunction with an oxidant.

Aging↗

PubMed2003

Oral administration of Bifidobacterium longum culture condensate in a diet-restricted murine peritonitis model enhances polymorphonuclear neutrophil recruitment into the local inflammatory site.

Dietary restriction impairs polymorphonuclear neutrophil (PMN) recruitment into the local inflammatory site, resulting in susceptibility to infection. Probiotics enhance host immunity via conditioning host intestinal microflora. Oral administration of Bifidobacterium longum culture condensate (BCC) in a diet-restricted murine peritonitis model may enhance PMN recruitment into the inflammatory site. Male ICR mice (n = 40) were assigned in equal numbers to control or BCC groups and subjected to 75% restricted food intake for 7 d. During dietary restriction, controls received only standard mouse chow, whereas the BCC group received standard mouse chow containing 1% BCC. Mice were killed before (0 h) or after (2 or 4 h) intraperitoneal glycogen injection. Peritoneal lavage fluid and exudative cells were recovered by peritoneal lavage. Peritoneal exudative cell number was counted. Tumor necrosis factor-alpha, interleukin-6, macrophage inflammatory protein-2, and interleukin-10 concentrations in peritoneal lavage fluid were determined by enzyme-linked immunosorbent assay. CD11b, CD18, CD31, and CD62L expressions on circulating PMNs were measured by flow cytometry. Oral BCC administration upregulated PMN recruitment into the peritoneal cavity and increased peritoneal fluid cytokine concentrations as well as CD18 and CD62L expressions on circulating PMNs during glycogen-induced peritonitis. Oral BCC administration in a diet-restricted murine peritonitis model augmented PMN recruitment into the inflammatory site by upregulating cytokine concentrations in the local inflammatory site and adhesion molecule expression on circulating PMNs. Oral BCC administration may be a favorable modality for improving dietary restriction-induced host immunosuppression.

Administration, Oral↗

PubMed2003

Calorie restriction of a high-carbohydrate diet elevates the threshold of PTZ-induced seizures to values equal to those seen with a ketogenic diet.

The purpose of this study was to evaluate the contributions of ketonemia, caloric restriction, and carbohydrates to seizure protection in rats fed selected diets. Male Sprague-Dawley rats were fed experimental diets of two basic types, one high in carbohydrates and restricted to 90, 65, or 50% of the normal daily caloric requirement and the other a normal rodent chow diet restricted to 90 or 65% of the daily caloric requirement. After consuming their respective diets for 20 days, animals were subjected to tail-vein infusion of pentylenetetrazole (PTZ) to determine seizure threshold, taken as the dose required to evoke the first clonic reaction. Seizure thresholds were compared to those of rats fed control diets of either normal rodent chow fed ad libitum or a standard high-fat (ketogenic) diet calorie-restricted to 90% of daily caloric requirement, all animals age- and weight-matched at the time of diet onset. All diets were balanced for vitamins and minerals and contained at least 10% protein (by weight). Seizure threshold and ketonemia were elevated in both experimental diets in approximate proportion to the degree of calorie restriction. Animals fed the most severely restricted high-carbohydrate diet (50%) had seizure thresholds equal to those fed the ketogenic diet but had significantly lower ketonemia.

3-Hydroxybutyric Acid↗

PubMed1996

Long-term effects of restrictive culture conditions on Saccharomyces cerevisiae sec7 cells.

Long-term effects of restrictive conditions on the temperature-sensitive S. cerevisiae sec7 mutant were studied. By microscopic analysis no cell lysis could be detected of cells cultured for up to 19 days at 37 degrees C. The optical density as well as the cell number remained constant during the whole period under restrictive conditions. However, restrictive conditions decreased the incorporation of 35S-methionine into intracellular proteins in a reversible manner indicating that protein biosynthesis was inhibited whereas the cells remained alive. Northern blot experiments revealed that restrictive conditions did not markedly decrease the ratio of the mRNA levels to total RNA for the genes TEF1, TEF2, SUC2, and BGL2 up to 73 hours. However the content of total RNA decreased drastically with increasing incubation times at restrictive temperature. In spite of the reduced total RNA content, cells are capable of new synthesis of mRNA under restrictive conditions which was shown by incubation of the cells in the presence of actinomycin D--an inhibitor of the mRNA synthesis. Most of the cells which survived a long-term incubation at 37 degrees C are not able to divide and to form colonies immediately after their transfer to permissive conditions.

Fungal Proteins↗