Infertile times: response to damage in genets of the clonal sedge Carex bigelowii

Tolerance to grazing is a plant trait that can be adaptive in systems where plants are subjected to a diversity of herbivore attack types. To test the tolerance ability of the clonal sedge Carex bigelowii, which is food plant to several herbivores in alpine and arctic areas, and the potential fitness costs of this tolerance, replicated units of genets were subjected to three levels of damage throughout three consecutive seasons. The three levels of treatment were no damage, light damage and heavy damage, and the damage was conducted by tearing off all plant material at 3 and 0 cm above-ground respectively. The genets had no tolerance under damage in terms of sexual reproduction. In terms of clonal reproduction the genets showed tolerance under light damage but not under heavy damage. However, no fitness cost was found for this tolerance ability, i.e. genets had higher reproduction and growth under no damage. The average ramet weight had a similar decrease under both a low and high damage treatment. Changed partitioning of biomass between plant parts and reduced concentration of total non-structural carbohydrates (TNC) in storage organs are possible mechanisms for the ability to uphold clonal reproduction in response to damage. There were no significant indications that tolerance ability or its fitness cost differed between genets. Our results suggest that when subjected to heavy damage genets will only reproduce vegetatively. Consequently, it seems C. bigelowii has evolved to allocate resources to the survival of an already successful genet rather than to a potential new genet of unknown success.     

Can long range mechanical interaction between drugs and membrane proteins define the notion of molecular promiscuity? Application to P-glycoprotein-mediated multidrug resistance (MDR)

Background

Failure of treatment in over 90% of patients with metastatic cancer is due to acquired MDR. P-glycoprotein (Pgp) remains the archetypal drug membrane transporter expressed in many MDR cancer cells. Albeit the ATPase activity of Pgp is triggered by the presence of drug in the membrane, it is commonly assumed that when two drug molecules meet the same Pgp the protein cannot handle them efficiently due to steric effects and as a result the ATPase activity drops. However it is also possible that drug accumulating in the lipid-phase may affect the membrane in such a way that it imposes the mechanical closure of transporters by opposing the force mediated by ATP consumption. In this context, long range interactions between drug and membrane proteins could exist.

Methods

Recent data concerning Pgp structure have allowed us to formalize this hypothesis and we present a physico-mathematical model that is not based on predictive QSAR or other empirical methods applied to experimental data.

Results

Long range mechanical interactions between Pgp and drugs are predicted to occur at an external concentration of drug ~ 10–100 μM as previously determined experimentally at which concentration ~ 50% of transporters should be rendered inactive.

Conclusion

Distance interaction(s) between Pgp and drugs exist explaining an ill-defined effect concerning the ability of any drug to inhibit Pgp once a threshold concentration in the membrane has been reached.

General significance

Potential application of the theory in the field of pharmacology concentrating on the notion of molecular promiscuity and toxicity in drug discovery prediction is discussed.     

悦目金蛛拖牵丝力学性能的变异

蜘蛛丝作为一种具有优良机械性能的天然动物蛋白纤维,其特有的结构和机械性能与其生物学功能密切相关。由大壶状腺纺出的拖牵丝在蜘蛛的行走、建网、捕食、逃生、繁殖等多种生命活动中均发挥了重要的功能,其机械性能会受到多种内外因素相互作用的影响。本文对在不同体重、不同猎物饲养和不同营养状态3种条件下人工抽出的悦目金蛛(Argiope amoena)拖牵丝与其不同单丝间的力学性能进行了比较研究。结果表明,悦目金蛛拖牵丝的力学性能在组间、组内不同个体,以及同一个体不同丝纤维间变异都较大。随着蜘蛛个体的增大,蛛丝横截面直径逐渐增大,这会使得蛛丝的力学性能更好,便于作为救命索的拖牵丝在遇到危险时承受蜘蛛体重;蜘蛛在经过1个月的饥饿后,蛛丝在屈服点附近的力学性能并未发生显著变化,而断裂点应变和断裂能均显著减小,同时也表明无论对于作为救命索还是网丝,拖牵丝的弹性形变性能在与蛛丝相关的微观进化中要优先于塑性形变。这是蜘蛛在能量摄入受到限制时对拖牵丝的投入权衡的结果。     

Flame retardant finishing of cotton fabric based on synergistic compounds containing boron and nitrogen

Boric acid and compound containing nitrogen, 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-HTAC) were used to finish cotton fabric. The flame retardant properties of the finished cotton fabrics and the synergetic effects of boron and nitrogen elements were investigated and evaluated by limited oxygen index (LOI) method. The mechanism of cross-linking reaction among cotton fiber, Tri-HTAC, and boric acid was discussed by FTIR and element analysis. The thermal stability and surface morphology of the finished cotton fabrics were investigated by thermogravimetric analysis (TGA) and scanning electron microscope (SEM), respectively. The finishing system of the mixture containing boron and nitrogen showed excellent synergistic flame retardancy for cotton fabric. The cotton fabric finished with mixture system had excellent flame retardancy. The LOI value of the treated cotton fabric increased over 27.5. Tri-HTAC could form covalent bonds with cellulose fiber and boric acid. The flame retardant cotton fabric showed a slight decrease in tensile strength and whiteness. The surface morphology of flame retardant cotton fiber was smooth.     

Purification and Properties of α-Glucosidase and Glucoamylase from Lentinus edodes (Berk.) Sing.

An α-glucosidase and a glucoamylase have been isolated from fruit bodies of Lentinus edodes (Berk.) Sing., by a procedure including fractionation with ammonium sulfate, DEAE-cellulose column chromatography, and preparative gel electrofocusing. Both of them were homogeneous on gel electrofocusing and ultracentrifugation. The molecular weight of α-glucosidase and glucoamylase was 51,000 and 55,000, respectively. The α-glucosidase hydrolyzed maltose, maltotriose, phenyl α-maltoside, amylose, and soluble starch, but did not act on sucrose. The glucoamylase hydrolyzed maltose, maltotriose, phenyl α-maltoside, soluble starch, amylose, amylopectin, and glycogen, glucose being the sole product formed in the digests of these substrates. Both enzymes hydrolyzed phenyl a-maltoside into glucose and phenyl α-glucoside. The glucoamylase hydrolyzed soluble starch, amylose, amylopectin, and glycogen, converting them almost completely into glucose. It was found that β-glucose was liberated from amylose by the action of glucoamylase, while α-glucose was produced by the α-glucosidase.

Maltotriose was the main α-glucosyltransfer product formed from maltose by the α-glucosidase.     

Effect of Chronic Caloric Restriction on the Circadian Regulation of Physiological and Behavioral Variables in Old Male B6C3F1 Mice

The circadian rhythms of food and water consumption, the number of feeding and drinking episodes, oxygen consumption, carbon dioxide production, respiratory quotient, gross motor activity, and body temperature were measured in male B6C3F, mice that were fed ad libitum (AL) or fed a caloric-restricted diet (CR). The CR regimen (60% of the normal AL consumption) was fed to mice during the daytime (5 hr after lights on). CR animals exhibited fewer feeding episodes but consumed more food per feeding bout and spent more total time feeding than AL mice. It appears that CR caused mice to change from their normal “nibbling behavior” to meal feeding. Compared to AL animals, the mean body temperature was reduced in CR animals, while the amplitude of the body temperature rhythm was increased. Spans of reduced activity, metabolism, and body temperature (torpor) occurred in CR mice for several hours immediately before feeding, during times of high fatty acid metabolism (low RQ). The acute availability of exogenous substrates (energy supplies) seemed to modulate metabolism shifting metabolic pathways to promote energy efficiency. CR was also associated with lower DNA damage, higher DNA repair, and decreased proto-oncogene expression. Most of the circadian rhythms studied seemed to be synchronized primarily to the feeding rather than the photoperiod cycle. Night-time CR feeding was found to be better than daytime feeding because the circadian rhythms for AL and CR animals were highly synchronized when this regimen was used.     

Late-maturing cooking rice Sensyuraku has excellent properties,equivalent to sake rice,for high-quality sake brewing

Low protein content and sufficient grain rigidity are desired properties for the rice used in high-quality sake brewing such as Daiginjo-shu (polishing ratio of the rice, less than 50%). Two kinds of rice, sake rice (SR) and cooking rice (CR), have been used for sake brewing. Compared with those of SR, analyses of CR for high-quality sake brewing using highly polished rice have been limited. Here we described the original screening of late-maturing CR Sensyuraku (SEN) as rice with low protein content and characterization of its properties for high-quality sake brewing. The protein content of SEN was lower than those of SR Gohyakumangoku (GOM) and CR Yukinosei (YUK), and its grain rigidity was higher than that of GOM. The excellent properties of SEN with respect to both water-adsorption and enzyme digestibility were confirmed using a Rapid Visco Analyzer (RVA). Further, we confirmed a clear taste of sake produced from SEN by sensory evaluation. Thus, SEN has excellent properties, equivalent to those of SR, for high-quality sake brewing.     

Determination of 2-Aminoethylphosphonic Acid and Its Y-iM ethyl Derivative in Animal Tissues by Gas Chromatography with Flame Photometric Detection

A sensitive and selective method was developed for the determination of 2-aminoethylphosphonic acid (AEP) and W-methyl AEP in animal tissues by gas chromatography (GC). These compounds were converted into their A-isobutoxycarbonyl methyl ester derivatives and measured by GC with flame photometric detection (FPd-GC), using 0.5 % FFAP on Uniport HP as the GC column packing. The calibration curves for AEP and A-methyl AEP in the range of 0.02 ~ 2 μg were linear, and the detection limit was about 20 pg as an injection amount. AEP and A^-methyl AEP in animal tissues were found in the free form and bound form with lipid and other biological macromolecules, and they could be measured without any influence from coexistent substances by FPd-GC. The recoveries of AEP and A'-methyl AEP added to the tissue samples were 92 —105 %, and their reproducibility was found to be satisfactory. The distribution of these compounds in various animals was also studied by using this new method.     

Design,synthesis, and anti-tumor activities of novel triphenylethylene–coumarin hybrids,and their interactions with Ct-DNA

Novel triphenylethylene–coumarin hybrid derivatives containing different amounts of amino side chains were designed and synthesized in good yields under microwave radiation. The derivatives 5b–d which possessed two amino side chains (except morpholinyl) showed a broad-spectrum and good anti-proliferative activity against five tumor cells and low cytotoxicity in osteoblast. UV–vis, fluorescence, and circular dichroism (CD) spectroscopies and thermal denaturation exhibited that compounds 10c, 5c, and 13c bearing amino side chain (except morpholinyl) on 4-phenyl had significant interactions with Ct-DNA by the intercalative mode of binding. Structure–activity relationships (SARs) analysis suggested that the amino alkyl chain would play an important role both in the compounds against tumor cells proliferation and their interactions with DNA.