Temperature acclimation affects thermal preference and tolerance in three Eremias lizards

We acclimated adult males of three Eremias lizards from different latitudes to 28℃,33℃ or 38℃ to examine whether temperature acclimation affects their thermal preference and tolerance and whether thermal preference and tolerance of these lizards correspond with their latitudinal distributions.Overall,selected body temperature（Tsel）and viable temperature range（VTR）were both highest in E.brenchleyi and lowest in E.multiocellata,with E.argus in between;critical thermal minimum（CTMin）was highest in E.multiocellata and lowest in E.brenchleyi,with E.argus in between;critical thermal maximum（CTMax）was lower in E.multiocellata than in other two species.Lizards acclimated to 28℃ and 38℃ overall selected lower body temperatures than those acclimated to 33℃;lizards acclimated to high temperatures were less tolerant of low temperatures,and vice versa;lizards acclimated to 28℃ were less tolerant of high temperatures but had a wider VTR range than those acclimated to 33℃ and 38℃.Lizards of three species acclimated to the three temperatures always differed from each other in CTMin,but not in Tsel,CTMax and VTR.Our results show that：temperature acclimation plays an important role in influencing thermal preference and tolerance in the three Eremias lizards,although the degrees to which acclimation temperature affects thermal preference and tolerance differ among species;thermal preference rather than tolerance of the three Eremias lizards corresponds with their latitudinal distributions.     

Effect of thermal acclimation on thermal preference,resistance and locomotor performance of hatchling soft-shelled turtle

The significant influence of thermal acclimation on physiological and behavioral performance has been documented in many ectothermic animals, but such studies are still limited in turtle species. We acclimated hatchling soft-shelled turtles Pelodiscus sinensis under three thermal conditions （10, 20 and 30~C） for 4 weeks, and then measured selected body temperature （Tsel）, critical thermal minimum （CTMin） and maximum （CTM~x）, and locomotor performance at different body temperatures. Thermal acclimation significantly affected thermal preference and resistance of P sinensis hatchlings. Hatchling turtles accli- mated to 10~C selected relatively lower body temperatures and were less resistant to high temperatures than those acclimated to 20~C and 30~C. The turtles＇ resistance to low temperatures increased with a decreasing acclimation temperature. The thermal re- sistance range （i.e. the difference between CTM~x and CTMin, TRR） was widest in turtles acclimated to 20~C, and narrowest in those acclimated to 10~C. The locomotor performance of turtles was affected by both body temperature and acclimation tem- perature. Hatchling turtles acclimated to relatively higher temperatures swam faster than did those acclimated to lower temperatures. Accordingly, hatchling turtles acclimated to a particular temperature may not enhance the performance at that temperature. Instead, hatchlings acclimated to relatively warm temperatures have a better performance, supporting the ＂hotter is better＂ hypothesis.     

Genome-wide analysis of Nilaparvata lugens nymphal responses to high-density and low-quality rice hosts

The brown planthopper （BPH） Nilaparvata lugens is an economically impor- tant pest on rice plants. In this study, the higher population density and yellow-ripe stage of rice plants were used to construct adverse survival conditions （ASC） against BPH nymphs. Simultaneously, the low population density and tillering stage of rice plants were used to establish a suitable survival condition （SSC） as a control. Solexa/Illumina sequencing was used to identify genes of BPH nymphs responding to ASC. Significantly longer duration development of BPH nymphs and significantly lower brachypterous ratio of BPH adults were observed by ASC compared with SSC. A total of 2 544 differentially expressed genes （DEGs） were obtained and analyzed by BLASTx, Gene Ontology and KEGG Orthology. Gene ontology analysis revealed that the DEGs were mainly involved in categories of cell, cell part, cellular process, binding, catalytic, organelle and metabolic processes. 1138 DEGs having enzyme commission numbers were assigned to different metabolic pathways. The largest clusters were neurodegenerative diseases （137, 12.0%）, followed by carbohy- drate metabolism （113, 9.9%）, amino acid metabolism （94, 8.3%）, nucleotide metabolism （76, 6.7%）, energy metabolism （64, 5.6%）, translation （60, 5.3%）, lipid metabolism （58, 5.1%）, and folding, sorting and degradation （52, 4.6%）. Expressing profile of 11 DEGs during eight nymphal developmental stages of BPH were analyzed by quantitative real- time polymerase chain reaction. The 11 genes exhibited differential expression between ASC and SSC during at least one developmental stage. The DEGs identified in this study provide molecular proof of how BPH reconfigures its gene expression profile to adapt to overcrowding and low-quality hosts.     

The nitrite oxidizing system of Nitrobacter winogradskyi

Abstract Cytochrome components which participate in the oxidation of nitrite in Nitrobacter winogradskyi have been highly purified and their properties studied in detail. Cytochrome a ₁ c ₁ is an iron-sulphur molybdoenzyme which has haems a and c and acts as a nitrite-cytochrome c oxidoreductase. Cytochrome c -550 is homologous to eukaryotic cytochrome c and acts as the electron mediator between cytochrome a ₁ c ₁ and aa ₃-type cytochrome c oxidase. The oxidase is composed of two kinds of subunits, has two molecules of haem a and two atoms of copper in the molecule, and oxidizes actively eukaryotic ferrocytochrome c as well as its own ferrocytochrome c -550. Further, a flavoenzyme has been obtained which has transhydrogenase activity and catalyses reduction of NADP⁺ with benzylviologen radical. This enzyme may be responsible for production of NADPH in N. winogradskyi . The electron transfer against redox potential from NO₂⁻ to cythochrome c could be pushed through prompt removal by cytochrome aa ₃ of H⁺ formed by the dehydrogenation of NO₂⁻+ H₂O. As cytochrome c in anaerobically kept cell-free extracts is rapidly reduced on addition of NO₂⁻, a membrane potential does not seem necessary for the reduction of cytochrome c by cytochrome a ₁ c ₁ with NO₂⁻ in vivo.     

SSR based linkage and mapping analysis of C,a yellow cocoon gene in the silkworm,Bombyx moil

The yellow color of the cocoon of the silkworm Bombyx mori is controlled by three genes, Y （Yellow haemolymph）, 1 （Yellow inhibitor） and C （ Outer-layer yellow cocoon）, which are located on linkage groups 2, 9 and 12, respectively. Taking advantage of a lack of crossing over in females, reciprocal backcrossed F1 （BC1） progeny were used for linkage analysis and mapping of the C gene using silkworm strains C 108 and KY, which spin white and yellow cocoons, respectively. DNA was extracted from individual pupae and analyzed for simple sequence repeat （SSR） markers. The C gene was found to be linked to seven SSR markers. All the yellow cocoon individuals from a female heterozygous backcross （BC1F） showed a heterozygous profile for SSR markers on linkage group 12, whereas individuals with light yellow cocoons showed the homozygous profile of the strain C108. Using a reciprocal heterozygous male backcross （BC1M）, we constructed a linkage map of 36.4 cM with the C gene located at the distal end, and the closest SSR marker at a distance of 13.9 cM.     

Appetite control： why we fail to stop eating even when we are full？

We often eat more than our body needs. We live in an environment where high calorie food is abundant and physical activities are limited. Living in this environment, maintaining healthy bodyweight becomes challenging and obesity becomes a social burden. Why do we continue to eat even after the metabolic needs are satisfied？ Feeding is an ancient behavior essential to survive. Thus the mechanisms to regulate appetite, energy expenditure, and energy storage are well conserved throughout animals. Based on this conservation, we study why we fail to control appetite using a simple genetic model system C. elegans. We have discovered certain genetic components that when misregulated have animals eat more and store more fat. In this review we discuss how these genes work in the appetite control circuit to ultimately understand overall appetite control behavior. We will also briefly discuss how social influence affects feeding regardless of the metabolic status of an animal.     

Computational screening of disease associated mutations on NPC1 gene and its structural consequence in Niemann-Pick type-C1

Niemann-Pick disease type C1 （NPC1）, caused by mutations of NPC1 gene, is an inherited lysosomal lipid storage disorder. Loss of functional NPC1 causes the accumulation of free cholesterol （FC） in endocytic organelles that comprised the characteristics of late endosomes and/or lysosomes. In this study we analyzed the pathogenic effect of 103 nsSNPs reported in NPC1 using computational methods. Rl186C, S940L, R958Q and I1061T mutations were predicted as most deleterious and disease associated with NPC1 using SIFT, Polyphen 2.0, PANTHER, PhD-SNP, Pmut and MUTPred tools which were also endorsed with previous in vivo experimental studies. To understand the atomic arrangement in 3D space, the native and disease associated mutant （Rl186C, S940L, R958Q and I1061T） structures were modeled. Quantitative structural and flexibility analysis was conceded to observe the structural consequence of prioritized disease associated mutations （R1186C, S940L, R958Q and I1061T）. Accessible surface area （ASA）, free folding energy （FFE） and hydrogen bond （NH bond） showed more flexibility in 3D space in mutant structures. Based on the quantitative assessment and flexibility analysis of NPC1 variants, I1061T showed the most deleterious effect. Our analysis provides a clear clue to wet laboratory scientists to understand the structural and functional effect of NPCI gene upon mutation.     

The nitrite oxidizing system of Nitrobacter winogradskyi

Cytochrome components which participate in the oxidation of nitrite in Nitrobacter winogradskyi have been highly purified and their properties studied in detail. Cytochrome a1c1 is an iron-sulphur molybdoenzyme which has haems a and c and acts as a nitrite-cytochrome c oxidoreductase. Cytochrome c-550 is homologous to eukaryotic cytochrome c and acts as the electron mediator between cytochrome a1c1 and aa3-type cytochrome c oxidase. The oxidase is composed of two kinds of subunits, has two molecules of haem a and two atoms of copper in the molecule, and oxidizes actively eukaryotic ferrocytochrome c as well as its own ferrocytochrome c-550. Further, a flavoenzyme has been obtained which has transhydrogenase activity and catalyses reduction of NADP+ with benzylviologen radical. This enzyme may be responsible for production of NADPH in N. winogradskyi. The electron transfer against redox potential from NO2- to cytochrome c could be pushed through prompt removal by cytochrome aa3 of H+ formed by the dehydrogenation of NO2- + H2O. As cytochrome c in anaerobically kept cell-free extracts is rapidly reduced on addition of NO2-, a membrane potential does not seem necessary for the reduction of cytochrome c by cytochrome a1c1 with NO2- in vivo.     

The effects of wind and thermal radiation on thermal responses during rest and exercise in a cold environment

1. 1. The purpose of this study was to investigate the effects of thermal radiation and wind on thermal responses at rest and during exercise in a cold environment.

2. 2. The experimental conditions were radiation and wind (R + W), no radiation and wind (W), radiation and no wind (R), no radiation and no wind (C).

3. 3. The air temperature was −5°C. Thermal radiation was 360 W/m². Air velocities were 0.76, 1.73 and 2.8 m/s. Rectal and skin temperatures, heart rate and oxygen consumption were recorded. Thermal and comfort sensations were questioned.

4. 4. There are no significant effects of thermal radiation and wind on the physiological responses except the mean skin temperature. There are significant effects on the mean skin temperature (P < 0.01) and thermal sensation (P < 0.05).

Cytochrome c1 complexes.

Cytochrome c1 forms an active complex with cytochrome c as previously reported (Chiang, Y. L., Kaminsky, L. S., and King, T. E. (1976) J. Biol. Chem. 251, 29-36). It also forms a complex with cytochrome oxidase with heme ratio of 1:1. This cytochrome c1.oxidase complex has been purified by ammonium sulfate fractionation and is stable in media of high ionic strength (greater than 0.1 M) but dissociates as the pH deviates from neutral. The purified cytochrome c1 aggregates to an oligomer, presumably a pentamer. No agent has been found to depolymerize isolated c1 without denaturation. However, in the cytochrome c1.oxidase complex, these two cytochromes apparently were depolymerized to form smaller aggregates, if not monomeric units, as judged by sedimentation behavior. Cytochrome c1 also forms a ternary complex with cytochrome c and oxidase in the heme ratio of 1:1:1. This complex can be prepared by any of the following four methods: (i) c1 + c + oxidase: (ii) c1.c complex + oxidase; (iii) c1 + c.oxidase complex: or (iv) c + c1.oxidase complex. The mode of formation of these complexes is all from pure protein-protein interactions. Cytochrome c1 is also incorporated into phospholipid vesicles and these vesicles show about 200 molecules of phospholipid/cytochrome c1 in terms of heme. The spectrophotometric, circular dichroic, sedimentation behavior and enzymic properties of these complexes have been investigated.     

Karyotypes of Sarcandra Gardn. and Chloranthus Swartz (Chloranthaceae) from China

Two species of Sarcandra and nine of Chloranthus in the Chloranthaceae from China were investigated cytologically. The basic chromosome number of both genera is x=15. In Sarandra the two species studied are diploid, and in Chloranthus seven species are diploid, one tetraploid ( C. fortune;, 2n = 60) and one hexaploid (C. henryi, 2n = 90). Chromosomes are medium-small to small, ranging in length from c . 6.0 μm to 1.O μ m. The katyotype formulas are as follow: S. glabra 2 n= 10m+ 10sm + 8st + 2stc; & hainanensvs 2n = 8m+ 12sm + 8st+2st^sat; C. spicatus 2n=12m+8sm + 6st + 4st^sat; C. erectus 2n= 12m + 4sm+ 12st + 2st^sat; C. serratus 2n=16m + 12sm + 2st^sat; C. sessilifolius 2n= 14m + 8sm + 6st+2st^sat; C. nervvosus 2n = 8m + 4sm + 6st + 2st^sat; C. angustfolius 2n = 20m + 6sm + 2sm^sat+ 2st^sat; C. japonicus 2n = 18m + 8sm + 4st^sat; C. fortunei 2n= 48m+4sm + 4st + 4st^sat. Karyotype asymmetries are of type 3B in C. erectus and C. nervosus and 2B in the other species. Based on these results, combined with the evidence from comparative morphology, anatomy, palynology and embryology, the relationship between Sarcandra and Chloranthus is discussed.     

Crystallization and preliminary X-ray diffraction study of cytochrome c552 from Hydrogenobacter thermophilus.

Cytochrome c552 from a thermophilic hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus, exhibits remarkable thermostability. The oxidized cytochrome c552 has been crystallized in an ethanol/water mixture by means of the vapor diffusion method. The crystals belong to the orthorhombic system, space group P2(1)2(1)2, with unit cell dimensions of a = 93.4 A, b = 52.9 A, and c = 32.4 A. Most probably the asymmetric unit contains two molecules of cytochrome c552. The crystals diffract X-rays to better than 2.5 A resolution and are stable to X-ray irradiation.     

Temperature regulation in a hypometabolic primate, the slow loris (Nycticebus coucang).

Six slow loris were exposed to air temperatures between 10 degrees C and 40 degrees C. Rectal temperature was stable (mean, 34.8 degrees C) at air temperatures between 17 degrees C and 31 degrees C; at higher air temperatures, the animals became hyperthermic. Oxygen consumption was minimal at air temperatures of 31.4-36.6 degrees C; the mean value (0.250 ml O2 g-1 h-1) was only 36% of the expected level for a eutherian Mammal. The slow loris increased its heat production at lower air temperatures. Thermal polypnea occurred in response to heat, and some of the animals were able to dissipate their entire metabolic heat production at lower air temperatures. Thermal polypnea occurred in response to heat, and some of the animals were able the combined thermal conductance of the tissues and haircoat was 73% of the predicted values. It was concluded that, in spite of its low metabolic rate, the slow loris had effective responses to moderate cold, and that, in addition, it was well adapted to a hot climate.     

Identification of the forms of cytochrome P-450 induced in rat liver by 2-acetylaminofluorene using immunoblotting and partial purification

The amounts of 5 different forms of cytochrome P-450 in liver microsomes from rats treated with 2-acetylaminofluorene were determined and compared with the corresponding patterns in microsomes from control, 3-methylcholanthrene- and phenobarbital-treated animals. 2-Acetylaminofluorene was found to increase the amount of cytochromes P-450b + e 10-fold and of cytochrome P-450d 3-fold, while there was a 54% increase in the level of cytochrome P-450 PB/PCN-E. Cytochrome P-450c was increased from a level too low to detect (less than 0.001 pmol/mg protein) to 0.019 pmol/mg protein. These findings were also confirmed by partial purification of cytochromes P-450b + e and c after 2-acetylaminofluorene treatment.     

Conformational isomerism and effective redox geometry in the oxidation of heme proteins by alkyl halides, cytochrome c, and cytochrome oxidase.

In contrast to its lethargy at physiological pH, horse heart cytochrome c can be oxidized at room temperature by the axial inner sphere oxidant bromomalononitrile (BMN) at higher acidities. The following stoichiometry obtains: 2Fe11 c + BrCH(CN2) + H+ leads to 2FeIII c + CH2(CN)2 + Br-, and the rate law is given by: rate = k2(FeIIc)(BMN). At an ionic strength of 1.0 (KCl), second-order rate constants vary from 300 l. per mol per sec (pH 2-3) to 0(pH 9). Below pH 6 there is a noticeable increase in rate with ionic strength while there is no specific salt effect for the process. At pH 7.4 there is no influence of added salt (0.01-1.0 M) upon the slow rate of reaction. The vast changes in rate occur over a pH region (3-6) in which only very minor changes in the visible spectrum of the cytochrome are manifest. The results are interpreted in terms of a conformational isomerism of cytochrome c in which the effective redox geometry alters from a predominantly "short C" form (in which an axial position is available for substitution) at lower pH's to a predominantly "C" form (axial positions encumbered) in the physiological region. At 5 degrees, pH 7.4, both hemes of beef heart cytochrome oxidase are oxidized by the addition of BMN (k2 = 29 plus or minus 3 l. per mol per sec). However, the reaction is inhibited by potassium cyanide and the protein containing iron(II) cyt alpha along with the cyano adduct of iron(II) or iron(III) cyt alpha3 is inert. The results demonstrate cytochrome alpha3 as the site of reaction and that alpha reduces alpha3 in the process. Cytochrome oxidase does catalyze the oxidation of cytochrome c with BMN as substrate. Taken together the results provide additional support for a recent theory and they demonstrate BMN to be an efficient probe for the effective redox geometry of a hemoprotein in solution.     

The interactions between cytochrome c and cytochrome oxidase that determine the conformation of the oxidized oxidase.

1. Cytochrome c2+ increases the rate at which cytochrome oxidase (EC 1.9.3.1) gamma max428nm) converts to its conformational isomer (gamma max 418-423 nm) but cytochrome c3+ has little effect on the conversion rate. 2. Interactions between reduced cytochrome oxidase and cytochrome c were studied in the absence of electron flow using anaerobic Sephadex columns. 3. Oxidase that is reduced by cytochrome c2+ or other reductant forms the 418-to 423-nm isomer if its last contact, before oxidation, is with cytochrome c3+. If the reduced oxidase contacts cytochrome c2+, before oxidation, the 428-nm oxidase forms.     

Alteration of hepatic glucocorticoid receptor stability and nuclear binding in vitro by citrate

Citrate greatly stabilized rat hepatic unbound glucocorticoid receptors in cell-free conditions at 4 degrees C with optimal effectiveness at 5-15 mM. Control receptors were inactivated at 4 degrees C with a half-life of less than 12 h. However, in the presence of 10 mM-citrate, unbound receptors were almost completely stabilized for 48 h at 4 degrees C. Citrate at a concentration of 1-2 mM yielded half-maximal stabilization. The stabilizing effect of citrate was rather specific, as succinate, alpha-oxoglutarate, oxaloacetate, malate and pyruvate had no apparent stabilizing action. Citrate stabilized receptors over a wide range of H+ concentrations, with complete protection between pH 6.5 and 8.5. In addition, citrate appeared to have a significant effect on glucocorticoid-receptor complex activation into a nuclear binding form. Thus 5-10 mM-citrate enhanced nuclear binding, with optimal activation achieved at 10 mM concentration. As analysed by sucrose-density-gradient centrifugation and DEAE-cellulose chromatography, no apparent change was observed in the physical characteristics of the glucocorticoid receptor in the presence of citrate.     

A new carbon monoxide-induced complex of cytochrome c oxidase.

Cytochrome c oxidase isolated from ox heart forms a complex in the presence of millimolar concentrations of CO with absorption bands at 606, 565 and 435 nm (difference spectrum), distinct from both ferrocytochrome a and the classical 590nm carbon-monoxyferrocytochrome a3. This species, which closely resembles Compound C, the derivative formed on photolysis and oxygenation of mixed-valence cytochrome a3+a32+CO, may represent a cytochrome a32+CO complex in which the associated ('invisible') copper is still oxidized.