Specific metabolic rate, longevity and "Rubner constant" for birds

An assumption was made that age constituent alpha x(beta) of mortality of individuals in a population in Weibull equation mx = m0 + alpha x(beta) (Ricklefs, 2000) reflects change of specific metabolic rate of one individual with age. Based upon that hypothesis a formula was proposed for relationship of specific metabolic rate of an adult individual after cessation of growth, when mass W is attained, and age t: q(t) = q0(1-omega(beta) + 1t(beta)) where q0 = aW(-b) is value q(t) at the moment of growth cessation and omega = alpha(1/(beta + 1)) is "ageing rate", determined and estimated by R. Ricklefs. Maximum longevity of an individual was determined as [equation: see text], where qcrit is specific metabolic rate at the age tmax. Parameter beta and relationships omega(W) and (qcrit/q0)(W) were approximated for birds from data of Ricklefs. Statistical comparison of results of calculations of tmax was carried out on the basis of the above formula and other known formulas for groups of Passeriformes and non-Passeriformes. Rubner constant [equation: see text] was calculated assuming that body mass of an adult individual (W) is attained in the first year of life (tA = 0). Average values of 602.4 +/- 2.5 kcal g(-1) (n = 83) for non-Passeriformes and 963 +/- 6.3 kcal g(-1) (n = 41) for Passeriformes were obtained.     

Diverse stages of sex-chromosome differentiation in tinamid birds: evidence from crossover analysis in <Emphasis Type="Italic">Eudromia elegans</Emphasis> and <Emphasis Type="Italic">Crypturellus tataupa</Emphasis>

All extant birds share the same sex-chromosome system: ZZ males and ZW females with striking differences in the stages of sex-chromosome differentiation between the primitive palaeognathus ratites and the large majority of avian species grouped within neognaths. Evolutionarily close to ratites is the neotropical order Tinamiformes that has been scarcely explored regarding their ZW pair morphology and constitution. Tinamous, when compared to ratites, constitute a large group among Palaeognathae, therefore, exploring the extent of homology between the Z and W chromosomes in this group might reveal key features on the evolution of the avian sex chromosomes. We mapped MLH1 foci that are crossover markers on pachytene bivalents to determine the size and localization of the homologous region shared by the Z and W chromosomes in two tinamous: Eudromia elegans and Crypturellus tataupa. We found that the homologous (pseudoautosomal) region differ significantly in size between these two species. They both have a single recombination event on the long arm of the acrocentric Z and W chromosomes. However, in E. elegans the pseudoautosomal region occupies one-fourth of the W chromosome, while in C. tataupa it is restricted to the tip of the long arm of the W. The W chromosomes in these two species differ in their heterochromatin content: in E. elegans it shows a terminal euchromatic segment and in C. tataupa is completely heterochromatic. These results show that tinamous have ZW pairs with more diversified stages of differentiation compared to ratites. Finally, the idea that the avian proto-sex chromosomes started to diverge from the end of the long arm towards the centromere of an acrocentric pair is discussed.     

Molecular genetic polymorphism of soil yeasts of the genus <Emphasis Type="Italic">Williopsis</Emphasis> from Taiwan Island

Comparative molecular genetic study of Williopsis yeasts isolated in different world regions reveals some peculiarities of species content in Taiwan. Some Williopsis yeasts may represent novel species. In Taiwan, four of the five known Williopsis species are documented: W. saturnus, W. suaveolens, W. mrakii, and W. subsufficiens. The W. saturnus yeasts predominate in Taiwanese soils, while W. suaveolens is more frequently isolated in Europe.     

An UDP-Glucosyltransferase Gene from Barley Confers Disease Resistance to <Emphasis Type="Italic">Fusarium</Emphasis> Head Blight

UDP-glucosyltransferases (UGTs) contribute to Fusarium head blight (FHB) resistance of wheat and barley by glycosylating the deoxynivalenol (DON), which is produced by Fusarium fungus. In this study, seven alleles of barley HvUGT14077 (GenBank No.GU170356.1) were cloned using RT-PCR. Among them, HvUGT-10W1, which was isolated from a FHB resistant barley variety 10W1, was significantly up-regulated in young spikes after F. graminearum (F.g) inoculation. HvUGT-10W1::GFP was subcellularly located in the plasma membrane and cytoplasm of the wheat protoplasts. In vitro antifungal activity assay showed that the HvUGT-10W1 protein exerted obvious inhibition against the growth of F.g. The silencing of the HvUGT-10W1 by virus-induced gene silencing (VIGS) resulted in compromised FHB resistance of 10W1, which was shown by the increased infected colonies on the leaves. These indicated that the barley HvUGT-10W1 may also contribute to F.g resistance in barley and provided a potential candidate gene to develop transgenic barley with enhanced FHB resistance.     

Yeast actin with a mutation in the "hydrophobic plug" between subdomains 3 and 4 (L266D) displays a cold-sensitive polymerization defect

Holmes et al. (Holmes, K. C., D. Popp, W. Gebhard, and W. Kabsch. 1990. Nature [Lond.] 347: 44-49) hypothesized that between subdomains 3 and 4 of actin is a loop of 10 amino acids including a four residue hydrophobic plug that inserts into a hydrophobic pocket formed by two adjacent monomers on the opposing strand thereby stabilizing the F- actin helix. To test this hypothesis we created a mutant yeast actin (L266D) by substituting Asp for Leu266 in the plug to disrupt this postulated hydrophobic interaction. Haploid cells expressing only this mutant actin were viable with no obvious altered phenotype at temperatures above 20 degrees C but were moderately cold-sensitive for growth compared with wild-type cells. The critical concentration for polymerization increased 10-fold at 4 degrees C compared with wild-type actin. The length of the nucleation phase of polymerization increased as the temperature decreased. At 4 degrees C nucleation was barely detectable. Addition of phalloidin-stabilized F-actin nuclei and phalloidin restored L266D actin''s ability to polymerize at 4 degrees C. This mutation also affects the overall rate of elongation during polymerization. Small effects of the mutation were observed on the exchange rate of ATP from G-actin, the G-actin intrinsic ATPase activity, and the activation of myosin S1 ATPase activity. Circular dichroism measurements showed a 15 degrees C decrease in melting temperature for the mutant actin from 57 degrees C to 42 degrees C. Our results are consistent with the model of Holmes et al. (Holmes, K. C., D. Popp, W. Gebhard, and W. Kabsch. 1990. Nature [Lond.]. 347:44-49) involving the role of the hydrophobic plug in actin filament stabilization.     

W14/15 esterase gene haplotype can be a genetic landmark of cultivars and species of the genus <Emphasis Type="Italic">Gentiana</Emphasis> L

We have identified multiple alleles for a single gene termed W14/15. This gene encodes closely related but not identical proteins W14 and W15 that accumulate in overwinter buds of Gentiana triflora (Takahashi et al. in Breed Sci 56:39–46, 2006; Hikage et al. in Mol Genet Genomics 278:95–104, 2007). In this study, structural analysis of the W14/15 gene was carried out for 21 different gentian lines/cultivars consisting of 5 different species, to survey species- or line/cultivar-specific haplotypes. Within the samples examined, multiple variant forms were found. Those were categorized into seven major types (type I–VII) and ten subtypes based on the presence of three short insertion/deletion sites, three RFLP sites, and several SNP sites. Each line/cultivar had a distinct set of W14/15 gene variants for an allelic pair. Phylogenetic analysis showed that the W14/15 alleles cluster into groups that are characteristic of gentian species, i.e., G. triflora, G. scabra, G. pneumonanthe, G. septemfida and an unknown species other than the former four. In addition, within the same gentian species, different sets of haplotypes were found. Thus, the W14/15 alleles provide useful landmarks to resolve phylogenies of the genus or section Gentiana, as well as to analyze pedigree and breeding history of the cultivars derived from those Gentiana sp.     

Physiological responses of three soybean species (<Emphasis Type="Italic">Glycine soja,G. gracilis</Emphasis>, and <Emphasis Type="Italic">G. max</Emphasis> cv. Melrose) to salinity stress

Understanding the mechanism for salt tolerance in wild soybean (Glycine soja) can help researchers improve that trait in cultivated soybean lines. We analyzed the effects of excess NaCl on the growth, physiology, and ion distribution in three soybean species: wild G. soja (W8), semi-wild G. gracilis (SW18), and the cultivated salt-sensitive G. max (cv. Melrose). These comparisons revealed that, under salt stress, shoot and root lengths and biomass (either shoot or root dry weights) were significantly higher for the W8 genotype than for the other two. Most of the morphological parameters for roots from the W8 plants were also increased, including total length, specific root length, and surface area. However, the average root diameter for W8 was significantly lower than that of either SW18 or ‘Melrose’ soybeans. In response to salinity, photosynthesis was suppressed to a greater extent in ‘Melrose’ than in W8. The relatively higher tolerance shown by W8 plants was also associated with lower levels of malondialdehyde, hydrogen peroxide, and relative electrical conductivity, but higher activities by superoxide dismutase and peroxidase, as well as more free proline and glycine betaine. In addition, the W8 plants contained less Na⁺ and Cl^?, but more K⁺, and they had a higher K⁺/Na⁺ ratio in their leaves and roots when compared with either SW18 or ‘Melrose’ plants. Therefore, the W8 genotype performs better in terms of seedling growth, photosynthetic characteristics, and physiological indexes. These findings provide guidance for developing new soybean cultivars with improved tolerance to salt stress. Our data also contribute to the knowledge base for plant salt tolerance as a tool for increasing the yields of other crops in high-salinity soils.     

Effects of leaf litter on inter-specific competitive ability of the invasive plant <Emphasis Type="Italic">Wedelia trilobata</Emphasis>

Allelochemicals released by invasive plants contribute to the successful invasion of new habitats. However, the relationship between allelopathic effects and competitive ability of invasive plants has not been characterized. We quantified the neighbor effects of Wedelia trilobata (family: Asteraceae) and the allelopathic effects of its leaf litter on two Asteraceae competitor species (invasive Eupatorium catarium and non-invasive Lactuca sativa) and on its own ramet growth. The seed germination rate and seedling biomass of the two competitor species decreased following treatment with W. trilobata leaf extracts. When co-cultured with W. trilobata, the total biomass of the two competitor species significantly decreased regardless of whether leaf extracts were present. Under low plant density co-culture conditions, W. trilobata leaf extracts enhanced the inhibitory effects on E. catarium. In contrast, W. trilobata leaf extracts promoted the growth of W. trilobata adventitious roots, resulting in increased competitive ability. Therefore, W. trilobata growth was promoted by its own allelochemicals in leaf extracts, whereas the growth of the invasive and non-invasive competitors was inhibited by the same chemicals. These responses facilitated the invasion by W. trilobata. Our study demonstrates that leaf litter of invasive plants may inhibit the growth of neighboring species to enhance the competitive ability of the invasive plants during the early stages of invasion.     

A critical evaluation of HL-A phenotype and genotype frequencies in a large German population determined by platelet complement fixation and lymphocytotoxicity

Summary 1047 healthy, random blood donors were typed independently for HL-A antigens by platelet complement fixation and lymphocytotoxicity. The results of both methods were analyzed statistically and the gene frequencies calculated. The gene frequencies were: first HL-A locus: 1: 0.1277–0.1316; 2: 0.3018–0.3053; 3: 0.1411–0.1456; 9: 0.1061–0.1088; 10: 0.0540–0.0564; 11: 0.0381–0.0416; W28: 0.0096–0.0271; W32: 0.0365–0.0469; second HL-A locus: 5: 0.0613–0.0649; 7: 0.1367–0.1401; 8: 0.0716–0.0920; 12: 0.0383–0.0903; 13: 0.0357–0.0371; W5: 0.0786–0.0844; W10: 0.0594–0.0620; W14: 0.0280–0.0315; W15: 0.0650–0.0722; W17: 0.0399; W18: 0.0241–0.0374; W22: 0.0037–0.0161; W27: 0.0406–0.0532; W21: 0.0329–0.0428. The discrepancies of typing results are discussed and their practical importance for paternity serology is stressed.Supported by the Deutsche Forschungsgemeinschaft (Mu 277/5).     

Three new coccidians (<Emphasis Type="Italic">Cyclospora</Emphasis>, <Emphasis Type="Italic">Eimeria</Emphasis>) from eastern moles, <Emphasis Type="Italic">Scalopus aquaticus</Emphasis> (Linnaeus) (Mammalia: Soricomorpha: Talpidae) from Arkansas,USA

Three new species of coccidians (Apicomplexa: Eimeriidae) are described from eastern moles, Scalopus aquaticus (Linnaeus) from Arkansas. Oöcysts of Cyclospora duszynskii n. sp. are subspheroidal with a smooth bi-layered wall, measure 11.4 × 10.0 µm, and have a length/width (L/W) ratio of 1.1; both micropyle and oöcyst residuum are absent, but a single polar granule is present. Sporocysts are ellipsoidal and measure 7.2 × 5.4 µm, L/W 1.3; an indistinct Stieda body is present, but the sub-Stieda and para-Stieda bodies are absent and the sporocyst residuum is composed of medium to large granules of different sizes along the edge of the sporocyst. Oöcysts of Cyclospora yatesi n. sp. are subspheroidal to ovoidal with an ornate outer wall, measure 17.0 × 15.2 µm, L/W 1.1; both micropyle and oöcyst residuum are absent, but a single polar granule is present. Sporocysts are ellipsoidal and measure 9.7 × 7.3 µm, L/W 1.3; an indistinct Stieda body is present, but sub-Stieda and para-Stieda bodies are absent and the sporocyst residuum is composed of medium to large granules of different sizes along the edge of the sporocyst. Oöcysts of Eimeria paulettefordae n. sp. are ovoidal to ellipsoidal with an ornate outer wall, measure 30.0 × 25.4 µm, L/W 1.2; both micropyle and oöcyst residuum are absent, but a single polar granule is present. Sporocysts are ellipsoidal and measure 12.6 × 9.2 µm, L/W 1.4; a button-like Stieda body is present, but sub-Stieda and para-Stieda bodies are absent and the sporocyst residuum is composed of medium to large granules of different sizes along the edge of the sporocyst. These are the first coccidians described from Arkansas populations of S. aquaticus. In addition, a summary is provided on the cyclosporans and eimerians from North American talpids.     

<Emphasis Type="Italic">Warneckea austro-occidentalis</Emphasis>, a new species from Cameroon and Nigeria,and re-evaluation of <Emphasis Type="Italic">W. fascicularis</Emphasis> var. <Emphasis Type="Italic">mangrovensis</Emphasis> (Melastomataceae-Olisbeoideae)

Summary  Described and illustrated is Warneckea austro-occidentalis R. D. Stone, an endemic of tropical forests in Cameroon’s South West Province and adjacent Nigeria. The name W. mangrovensis (Jacq.-Fél.) R. D. Stone is also proposed at species level for the taxon originally described as W. fascicularis var. mangrovensis Jacq.-Fél. An IUCN (2001) status of endangered is assigned for both W. austro-occidentalis and W. mangrovensis.     

Intraprotein electron transfer and proton dynamics during photoactivation of DNA photolyase from E. coli: review and new insights from an "inverse" deuterium isotope effect

We review our work on electron transfer and proton dynamics during photoactivation in DNA photolyase from E. coli and discuss a recent theoretical study on this issue. In addition, we present unpublished data on the charge recombination between the fully reduced FADH(-) and the neutral (deprotonated) radical of the solvent exposed tryptophan W306. We found a pronounced acceleration with decreasing pH and an inverse deuterium isotope effect (k(H)/k(D)=0.35 at pL 6.5) and interpret it in a model of a fast protonation equilibrium for the W306 radical. Due to this fast equilibrium, two parallel recombination channels contribute differently at different pH values: one where reprotonation of the W306 radical is followed by electron transfer from FADH(-) (electron transfer time constant tau(et) in the order of 10-50 micros), and one where electron transfer from FADH(-) (tau(et)=25 ms) is followed by reprotonation of the W306 anion.     

The relationship between antioxidant compounds contents and antioxidant enzymes under water-deficit stress in the three Iranian cultivars of basil (<Emphasis Type="Italic">Ocimum basilicum</Emphasis> L.)

The current investigation was conducted to elucidate the potential modulatory functions of both enzymatic and non-enzymatic scavenging elements of three Iranian basil (Ocimum basilicum L.) cultivars in response to different water-deficit stress treatments [i.e., control (W1: 100 % FC), mild (W2: 75 % FC), moderate (W3: 50 % FC), and severe (W4: 25 % FC)]. In general, the growth parameters, viz., plant height, number of lateral branches, number of flowers in the inflorescence per plant, and dry and fresh weights of leaves and inflorescence followed by yield were considerably affected by water-deficit stress levels (p ≤ 0.05), though some fluctuations were observed among three cultivars. Under severe water-deficit stress (W4), total chlorophyll content overall increased, while a pronounced reduction in the carotenoid content was observed by boosting of water-deficit stress intensities. Apart from some quantitative variations, ROS-scavenging enzymes, such as SOD, CAT, APX, GPX, and PPO, exhibited different behaviors versus different levels of water-deficit stress in the basil cultivars, concluding that their modulation could be a cultivar-dependent mechanism and stress-dependent mechanism. Among different metabolites detected in the essential oil of basil cultivars, both methyl chavicol and squalene were superior in the cultivars 2 and 3, while in cultivar 1, linalool and squalene were the predominant constituents, under water deprivation conditions. Taking all the features studied here into consideration, presumably, cultivar 1 is qualified enough to nominate as the most tolerant basil cultivar, could be accordingly utilized as a promising source/material for breeding programs of basil under drought stress, and possibly other abiotic stresses.     

No foundation of a "3/4 power scaling law" for respiration in biology

Respiration rate ( R ) as a function of body mass ( W   ) is usually expressed as R  =  aW ^b . Empirically, the b value is often close to 3/4 when organisms covering a large span in body mass are compared. But recent years research on the energetic cost of growth demonstrate that young and fast growing stages show higher weight specific respiration rates than older and adult stages, and this implies that the b values tend to be higher: b ∼ 1 in small (young) organisms falling to b  = 0.6–0.7 in larger (older) stages. Thus, respiration and growth are integrated through the energetic costs of growth. This explains why the b value is not a "natural constant" and why a "3/4 power scaling law" cannot be deduced from the interplay between pure physical and geometric constraints of the transport of oxygen.     

Protection of Energy Transfer Process in Isolated Phycobilisome by "White Light" from Ultraviolet-B Induced Damage in the Cyanobacterium Spirulina Platensis

Effect of UV-B (1.9 W m^-2) alone or in combination with supplemental "white light". WL (20 W m^-2) exposure was studied on the energy transfer process of intact phycobilisomes isolated from Spirulina platensis. Exposure of UV-B or supplemental irradiation induced a decrease in room temperature fluorescence intensity and caused a shift towards shorter wavelengths. The low temperature fluorescence measurements showed that UV-B impairs energy transfer from phycocyanin to allophycocyanin B and the extent of damage may be reduced by the exposure to supplemental WL.     

Responses of nonstructural carbohydrates to shoot removal and soil moisture treatments in <Emphasis Type="Italic">Salix nigra</Emphasis>

Aboveground disturbances are common in dynamic riparian environments, and Salix nigra is well adapted with a vigorous resprouting response. Soil moisture stresses are also common, and S. nigra is flood tolerant and drought sensitive. The objective of this study was to quantify nonstructural carbohydrate (NSC) reserves in S. nigra following shoot removal and soil moisture treatments. NSC reserves provide energy for regeneration of shoot tissue until new functional leaves are developed. Three soil moisture treatments: well-watered (W), periodic flooding (F) and drought (D); and three shoot removal treatments: no shoots removed (R0), partial shoot removal (R1), and complete shoot removal (R2) were applied. Plants were harvested when new shoot development was observed (day 13). Statistical significance in the 3 × 3-factorial design was determined in two-factor ANOVA at P < 0.05. Both roots and cuttings were important reservoirs for NSC during resprouting response, with decreases in root (31%) and cutting (14%) biomass in R2 compared to R0. Rapid recovery of photosynthetic surface area (from 15 to 37% of R0) was found in R1. A clear pattern of starch mobilization was found in roots in R0, R1 and R2, with lowest root starch concentration in W, F higher than W, and D higher than F. Shoot starch concentration was lower in F and D compared to W in R0, however, in R1 shoot starch was reduced in W compared to F and D, possibly indicating reduced rates of translocation during soil moisture stress. Evidence of osmotic adjustment was found in roots and shoots with higher total ethanol-soluble carbohydrates (TESC) during soil moisture stress in F and D treatments. Total plant NSC pool was greater in F and D treatments compared to W, and progressively reduced from R0 to R1 to R2. Results indicated negative effects of drought, and to a lesser extent periodic flooding on resprouting response in S. nigra, with implications for reduced survival when exposed to combined stresses of aboveground disturbance and soil moisture.     

Protection of Energy Transfer Process in Isolated Phycobilisome by "White Light" from Ultraviolet-B Induced Damage in the Cyanobacterium Spirulina Platensis

Effect of UV-B (1.9 W m^-2) alone or in combination with supplemental "white light". WL (20 W m^-2) exposure was studied on the energy transfer process of intact phycobilisomes isolated from Spirulina platensis. Exposure of UV-B or supplemental irradiation induced a decrease in room temperature fluorescence intensity and caused a shift towards shorter wavelengths. The low temperature fluorescence measurements showed that UV-B impairs energy transfer from phycocyanin to allophycocyanin B and the extent of damage may be reduced by the exposure to supplemental WL. This revised version was published online in June 2006 with corrections to the Cover Date.     

Physical separation of "suppressor" from "helper" thymocytes.

Thymocytes from 1-month-old NZB/W mice were separated at unit gravity and then studied for helper or suppressor effects in a GVH assay. Thymocytes with a settling rate of 4 to 6 mm/hr suppressed but did not help. In contrast, help but no suppression characterized thymocytes settling at 6 to 10 mm/hr. Thus helper and suppressor thymocytes in this GVH assay were physically separated.