Effect of Neurotensin Peptidomimetics on Thermoregulation in Rats

The effects of the tripeptide analogues of neurotensin, GZR123 and GZR125, on thermoregulation was studied in rats that were kept at different ambient temperatures ( _c): in the cold ( _c = 4–6°C), thermoneutral ( _c = 27–28°C), and hot ( _c = 31–32°C) environment, as well as at room temperature ( _c = 20–21°C). In the cold environment, the injection of GZR123 disturbed the vegetative mechanisms of heat emission, leading to peripheral vasoconstriction and possibly changing heat production. Similar to neurotensin, GZR125 disturbed the development of compensatory vasoconstriction in the cold environment and at room temperature, which resulted in a decrease in body temperature. At high temperature, this peptide induced vasodilation.     

Effect of [DAla4]-Dermorphin and Its Analogs on the Functional Status of the Thermoregulation System in Rats at Different Environmental Temperature

We studied the influence of [DAla⁴]-dermorphin ([DAla⁴]-DM), its fragments ([DAla⁴]-DM_2–7, [DAla⁴]-DM_3–7, and [DAla⁴]-DM_4–7) and analogs ([Trp¹, DAla⁴]-DM, [DArg², DAla⁴]-DM, and [DOrn², DAla⁴]-DM) on the functional status of the thermoregulation system in rats at different thermal environments: cold (4–6°C), thermoneutral (27–28°C) and hot (31–32°C). [DAla⁴]-DM administration proved to induce temperature- and dose-dependent hypothermia and vasomotor responses. No activity of the peptide was observed in the hot environment. N-terminal shortening of the peptide inhibits its thermoregulatory activity. Tyr¹ to Trp¹ substitution nearly completely suppressed the thermoregulatory effects. DAla² to DArg² substitution decreased the hypothermic effect and only the vasodilatory response was observed in the comfortable environment. DAla² to DOrn² substitution completely suppressed the hypothermic effect in the cold environment and considerably attenuated the vasodilatory response in the thermoneutral environment.     

Effect of Oxytocin on the Emotional State and Behavior of Rats under Stress Conditions

Oxytocin, a hormone exerting controlling effects on lactation, sexual and maternal behavior, and cyclic organization of sleep and wakefulness, is capable of significantly modulating reactions of the organism to the action of stressogenic stimuli. We studied the effects of injections of synthetic oxytocin on the behavioral phenomena and emotional state of rats during realization of a proconflict test induced by “punishments” (nociceptive electrical stimuli) in the process of drinking after water deprivation. Intraperitoneal injections of oxytocin in a 4.0 μg dose resulted in shortening of the delays of coming of rats to a water dish and also in an increase in the number of drinks of water punished by electrical stimulation, as compared with the corresponding indices in control animals. After oxytocin injections, the intensity of research activity of rats in the open field, in general, increased. After realization of the proconflict test, locomotor and orientational/research activities in animals preliminarily injected with oxytocin were much more intense than those in control rats (in the latter ones, these activities were sharply suppressed). Injections of oxytocin also led to certain normalization of the emotional state; after the proconflict test, negative shifts in this state in control rats were obvious. Therefore, oxytocin appreciably increases the resistivity of the organism against stress.     

Turnover of Phospholipids in Bacillus cereus under Various Growth Conditions

As a search for natural antioxidants from plant materials, strong antioxidative activity was observed in leaf waxes extracted from Eucalyptus species. A novel type of antioxidant was isolated from the leaf wax of Eucalyptus globulus and identified as n-tritriacontan-16,18-dione. Antioxidative activities were determined by different methods; a thiocyanate method, a thiobarbituric acid method, a total carbonyl value method and a weighing test. The anti-oxidant showed remarkable antioxidative activity in a water/alcohol system and was more effective than α-tocopherol and BHA; however, it has no antioxidative activity in an oil system.     

Effect of Dim and Bright Light Exposure on Some Immunological Parameters Measured under Thermal Neutral Conditions

This study assesses the effects of ambient light conditions, under a thermoneutral environment, on selected immunological parameters of 7 healthy young women (aged 19 to 22 yrs). Subjects entered the bioclimatic chamber at 11∶00 h, controlled at 26°C and 60% relative humidity, a “neutral climate”. They lead a well‐regulated life in the climatic chamber (pre‐condition) while exposed to dim (200 lux) or, on the next day, bright (5000 lux) light between 06∶00 to 12∶00 h. Just before the end of each period of light exposure, a blood sample was taken for later immunological assay of white blood cell count (WBC), phagocytosis, interferon‐γ (IFN‐γ), interleukin‐4 (IL‐4), CD69 T cells (CD69), CD4⁺CD25⁺ T cells (CD4⁺CD25⁺), and transforming growth factor‐β 1 (TGF‐β1). The results, when compared with the pre‐condition, were as follows: 1) CD69 and IFN‐γ increased during normal conditions without thermal stress under dim light; 2) WBC increased and IL‐4 decreased under bright light; 3) as shown by the highly significant decrease of TGF‐β1, the immune system was activated under bright light; 4) phagocytosis tended to increase under bright light exposure; 5) CD69 and IFN‐γ were significantly higher, and CD4⁺CD25⁺ tended to decrease under bright light; 6) phagocytosis tended to be lower and TGF‐β1 significantly higher under dim light, indicating a decline of immune system function. Taken together, this preliminary single time‐point sampling study infers that some parameters are activated (CD69) while others are attenuated (phagocytosis, TGF‐β1) according to the environmental light intensity, dim vs. bright, in women adhering to a standardized routine in the absence of thermal stress. These findings are discussed in terms of inhibition of the sympathetic and excitation of the parasympathetic nervous system under the influence of life‐style regularity and daytime bright light exposure.     

Macronutrient Self-Selection Pattern in Rats under Different Lighting Conditions

The effect of constant darkness (DD) and constant light (LL) on the circadian pattern of macronutrient self-selection, daily food intake and body weight was analysed in rats using an automated computer system. No significant differences in energy intake were observed between groups as regards energy intake or macronutrient preferences. Fat and CHO intakes showed a negative correlation (p < 0.005 in LL and p < 0.0005 in DD and LD), while protein intake remained constant, which suggests the existence of separate regulation mechanisms governing the intake of protein and energy. Energetic requirements can be preponderantly covered by CHO or fat, depending on the preferences of the animal. Body weight measurements reflected no significant variations between groups at the end of the experiment. However, the circadian pattern of wheel-running activity and the intake of the three macronutrients measured in both constant lighting conditions varied with respect to that observed in LD. This was particularly true in the case of LL, when constant illumination exerted a decoupling effect on the rhythms. The results indicate that lighting conditions modulate the circadian pattern of wheel-running activity and macronutrient intake. However, changes in temporal organisation of food intake did not affect macronutrient preferences, daily energy intake, number of meals, feeding duration or body weight, suggesting the existence of a double, circadian and homeostatic, control of such variables.     

Volatile Compounds Originating from Mixed Microbial Cultures on Building Materials under Various Humidity Conditions

We examined growth of mixed microbial cultures (13 fungal species and one actinomycete species) and production of volatile compounds (VOCs) in typical building materials in outside walls, separating walls, and bathroom floors at various relative humidities (RHs) of air. Air samples from incubation chambers were adsorbed on Tenax TA and dinitrophenylhydrazine cartridges and were analyzed by thermal desorption-gas chromatography and high-performance liquid chromatography, respectively. Metabolic activity was measured by determining CO₂ production, and microbial concentrations were determined by a dilution plate method. At 80 to 82% RH, CO₂ production did not indicate that microbial activity occurred, and only 10% of the spores germinated, while slight increases in the concentrations of some VOCs were detected. All of the parameters showed that microbial activity occurred at 90 to 99% RH. The microbiological analyses revealed weak microbial growth even under drying conditions (32 to 33% RH). The main VOCs produced on the building materials studied were 3-methyl-1-butanol, 1-pentanol, 1-hexanol, and 1-octen-3-ol. In some cases fungal growth decreased aldehyde emissions. We found that various VOCs accompany microbial activity but that no single VOC is a reliable indicator of biocontamination in building materials.     

Effect of Structural Changes of Pro6 in Dermorphin Molecule on Its Antinociceptive Activity

We studied effect of dermorphin (H-Tyr-DAla-Phe-Gly-Tyr-Pro-Ser-NH₂) and its analogs with modified amino acid residue proline in position 6, H-Tyr-DAla-Phe-Gly-Tyr-[DPro]-Ser-NH₂, H-Tyr-DAla-Phe-Gly-Tyr-[dehydro-Pro]-Ser-NH₂, and H-Tyr-DAla-Phe-Gly-Tyr-[D-dehydro-Pro]-Ser-NH₂, on nociception in the tail-flick and hot plate tests after intraperitoneal injection. Replacement of LPro with the stereoisomer DPro as well as Pro dehydration (LdHPro) was shown to increase antinociceptive activity. Replacement of LdHPro with DdHPro cancelled the activity in the tail-flick test. All three dermorphin analogs retained antinociceptive activity in the hot plate test; however, the effect of dermorphin was more pronounced.     

Effect of a Magnetic Field on Drosophila under Supercooled Conditions

Under subzero degree conditions, free water contained in biological cells tends to freeze and then most living things die due to low temperatures. We examined the effect of a variable magnetic field on Drosophila under supercooled conditions (a state in which freezing is not caused even below the freezing point). Under such supercooled conditions with the magnetic field at 0°C for 72 hours, −4°C for 24 hours and −8°C for 1 hour, the Drosophila all survived, while all conversely died under the supercooled conditions without the magnetic field. This result indicates a possibility that the magnetic field can reduce cell damage caused due to low temperatures in living things.     

Functional Body Capacities under the Conditions of Various Concentrations of Carbon Dioxide and Oxygen

We determined a permissible ratio between carbon dioxide and oxygen concentrations during accidental situations. The experiments (n = 138, 10 h each) on the effect of various concentrations of carbon dioxide and oxygen in the inhaled air were conducted on male volunteers aged 20–40 years subjected to a special medical examination. All experiments were divided into five series: hypercapnia + normoxia, hypercapnia + hyperoxia, hypercapnia + hypoxia, normocapnia + hypoxia, and ambient air (control). The results showed that functional capacities of the body are less impaired under the conditions of hypercapnia combined with hyperoxia. Thus, in accidental situations associated with rapid accumulation of carbon dioxide in the atmosphere of airtight chambers, a synchronous increase in pO₂ to 220–230 torr can provide for the highest work capacity.     

Photosynthetic Electron Transport under Phosphorylating Conditions as Influenced by Different Concentrations of Various Salts

Osman, M. E-A. H. and El-Shentenawy, F. 1988. Photosyntheticelectron transport under phosphorylating conditions as influencedby different concentrations of various salts.—J. exp.Bot. 39: 859–863. The rate of light-induced electron transport by isolated spinachthylakoids under phosphorylating conditions, as affected bydifferent concentrations of Br^–, Cl^–, NO₃^–,HCO₃^–, SO₄^2– and CO₃^2– has been investigated.The results show that both low and high concentrations of HCO₃^2–stimulated the oxygen evolution capacity under phosphorylatingconditions, whereas only low concentrations of CO₃^2–,SO₄^2– and Cl^– stimulated the oxygen evolution capacity.However, irrespective of concentration, both Br^– and NO₃^–reduced this capacity. The rate of photosynthetic electron transportwas generally stimulated by addition of ADP, even in cases whereelectron transport was inhibited by addition of bromide andnitrate. The different concentrations of these anions also causedreduction of the power generated by proton pumping and usedfor phosphorylation. The greatest level of reduction was observedin the presence of high concentrations of Cl^– and HCO₃^–. Key words: Spinach thylakoids, photosynthetic electron transport, phosphorylation     

Survival of Methanogenic Archaea from Siberian Permafrost under Simulated Martian Thermal Conditions

Methanogenic archaea from Siberian permafrost complementary to the already well-studied methanogens from non-permafrost habitats were exposed to simulated Martian conditions. After 22 days of exposure to thermo-physical conditions at Martian low- and mid-latitudes up to 90% of methanogenic archaea from Siberian permafrost survived in pure cultures as well as in environmental samples. In contrast, only 0.3%–5.8% of reference organisms from non-permafrost habitats survived at these conditions. This suggests that methanogens from terrestrial permafrost seem to be remarkably resistant to Martian conditions. Our data also suggest that in scenario of subsurface lithoautotrophic life on Mars, methanogenic archaea from Siberian permafrost could be used as appropriate candidates for the microbial life on Mars.     

Effect of Hexose Analogs on Growth of Chilomonas paramecium

SYNOPSIS. Observations on the effect of 7 glucose analogs on growth of C. paramecium showed that 2-deoxy-D-glucose and 2-deoxy-D-galactose inhibited growth. Inhibition in 2-DG was not influenced by pH, calcium concentration, or by carbon sources as lactate, acetate, n -butyl alcohol, or succinate. Similarly, glucose or glucose-6-phosphate did not reverse inhibition. Organisms were viable in 2-DG only when a carbon source in the basal medium was absent. Wherever a useful carbon source was present, 2-DG was lethal in concentrations over 40 mg/100 ml. Phosphorylation of 2-DG did not occur. Lactic acid dehydrogenase was not inhibited. Glucose-6-phosphate dehydrogenase appears to have an affinity for 2-DG; phosphohexose isomerase activity was decreased by 2-DG.     

Dimethylmorpholinium Chloride Analogs and Their Effect on Plants

Relations between the chemical structure of new analogs of dimethylmorpholinium chloride (DMC) and their growth retardant activity were investigated. Some of these substances exerted a specific impact on the growth of individual organs in monocot (Triticum aestivum L., Hordeum vulgare ssp. distichon (L.) Koern.) and dicot (Phaseolus vulgaris L., Brassica napus L.) plants. Within the group of bis-quaternary ammonium salts, the derivatives of N-methylmorpholinium (1-DMC) and N-benzylmorpholinium (3-DMC) manifested high retardant activity on growth of barley and wheat plants. The molecules of these compounds comprise the chain of two methylene groups bridging the nitrogen atoms. An N-acetylmorpholinium derivative 17-DMC, with nitrogen atoms in morpholinium rings linked by two methylene groups with a CHOH group between them, produced a physiological effect on rape and kidney bean plants.     

Activity of the Enzymes of Carbon Metabolism in Sulfobacillus sibiricus under Various Conditions of Cultivation

The thermoacidophilic iron-oxidizing chemolithotroph Sulfobacillus sibiricus N1^T is characterized by steady growth and amplified cell yield when grown in vigorously aerated medium containing Fe²⁺, glucose, and yeast extract as energy sources. In this case, carbon dioxide, glucose, and yeast extract are used as carbon sources. Glucose is assimilated through the fructose-bisphosphate pathway and the pentose-phosphate pathway. The glyoxylate bypass does not function in S. sibiricus, and the tricarboxylic acid cycle is disrupted at the level of 2-oxoglutarate dehydrogenase. The presence of ribulose-bisphosphate carboxylase indicates that carbon dioxide fixation proceeds through the Calvin cycle. The activity of ribulose-bisphosphate carboxylase is highest in autotrophically grown cells. The cells also contain pyruvate carboxylase, phosphoenolpyruvate carboxylase, phosphoenolpyruvate carboxykinase, and phosphoenolpyruvate carboxytransphosphorylase.     

Leishmanicidal Effect of Synthetic trans-Resveratrol Analogs

Background

Stilbene-based compounds show antitumoral, antioxidant, antihistaminic, anti-inflammatory and antimicrobial activities. Here, we evaluated the effect of the trans-resveratrol analogs, pterostilbene, piceatannol, polydatin and oxyresveratrol, against Leishmania amazonensis.

Methodology/Principal Findings

Our results demonstrated a low murine macrophage cytotoxicity of all four analogs. Moreover, pterostilbene, piceatannol, polydatin and oxyresveratrol showed an anti-L. amazonensis activity with IC₅₀ values of 18 μM, 65 μM, 95 μM and 65 μM for promastigotes, respectively. For intracellular amastigotes, the IC₅₀ values of the analogs were 33.2 μM, 45 μM, 29 μM and 30.5 μM, respectively. Among the analogs assayed only piceatannol altered the cell cycle of the parasite, increasing 5-fold the cells in the Sub-G0 phase and decreasing 1.7-fold the cells in the G0-G1 phase. Piceatannol also changed the parasite mitochondrial membrane potential (ΔΨm) and increased the number of annexin-V positive promastigotes, which suggests incidental death.

Conclusion/Significance

Among the analogs tested, piceatannol, which is a metabolite of resveratrol, was the more promising candidate for future studies regarding treatment of leishmaniasis.     

Effects of Various Amino Acids on Methionine-Induced Hyperhomocysteinemia in Rats

Rats were fed diets supplemented with 1% L-methionine with and without 2.5% various amino acids for 7 d to determine what amino acids other than glycine, serine, and cystine can suppress methionine-induced hyperhomocysteinemia. L-Glutamic acid, L-histidine, and L-arginine significantly suppressed methionine-induced enhancement of plasma homocysteine concentrations, but the mechanisms underlying the effect of these amino acids are thought not to be identical.     

Application of Zero-Valent Iron Nanoparticles for the Removal of Aqueous Zinc Ions under Various Experimental Conditions

Application of zero-valent iron nanoparticles (nZVI) for Zn²⁺ removal and its mechanism were discussed. It demonstrated that the uptake of Zn²⁺ by nZVI was efficient. With the solids concentration of 1 g/L nZVI, more than 85% of Zn²⁺ could be removed within 2 h. The pH value and dissolved oxygen (DO) were the important factors of Zn²⁺ removal by nZVI. The DO enhanced the removal efficiency of Zn²⁺. Under the oxygen-contained condition, oxygen corrosion gave the nZVI surface a shell of iron (oxy)hydroxide, which could show high adsorption affinity. The removal efficiency of Zn²⁺ increased with the increasing of the pH. Acidic condition reduced the removal efficiency of Zn²⁺ by nZVI because the existing H⁺ inhibited the formation of iron (oxy)hydroxide. Adsorption and co-precipitation were the most likely mechanism of Zn²⁺ removal by nZVI. The FeOOH-shell could enhance the adsorption efficiency of nZVI. The removal efficiency and selectivity of nZVI particles for Zn²⁺ were higher than Cd²⁺. Furthermore, a continuous flow reactor for engineering application of nZVI was designed and exhibited high removal efficiency for Zn²⁺.