High oxidative damage levels in the longest-living rodent, the naked mole-rat

Oxidative stress is reputed to be a significant contributor to the aging process and a key factor affecting species longevity. The tremendous natural variation in maximum species lifespan may be due to interspecific differences in reactive oxygen species generation, antioxidant defenses and/or levels of accrued oxidative damage to cellular macromolecules (such as DNA, lipids and proteins). The present study tests if the exceptional longevity of the longest living (> 28.3 years) rodent species known, the naked mole-rat (NMR, Heterocephalus glaber ), is associated with attenuated levels of oxidative stress. We compare antioxidant defenses (reduced glutathione, GSH), redox status (GSH/GSSG), as well as lipid (malondialdehyde and isoprostanes), DNA (8-OHdG), and protein (carbonyls) oxidation levels in urine and various tissues from both mole-rats and similar-sized mice. Significantly lower GSH and GSH/GSSG in mole-rats indicate poorer antioxidant capacity and a surprisingly more pro-oxidative cellular environment, manifested by 10-fold higher levels of in vivo lipid peroxidation. Furthermore, mole-rats exhibit greater levels of accrued oxidative damage to lipids (twofold), DNA (~two to eight times) and proteins (1.5 to 2-fold) than physiologically age-matched mice, and equal to that of same-aged mice. Given that NMRs live an order of magnitude longer than predicted based on their body size, our findings strongly suggest that mechanisms other than attenuated oxidative stress explain the impressive longevity of this species.     

Caecal function provides the energy of fermentation without liberating heat in the poikilothermic mammal,Heterocephalus glaber

Summary This paper presents the first report of a mammalian internal organ with a lower temperature than its abdominal surrounds. Heterocephalus glaber, the naked mole-rat, is a poikilothermic mammal that leads a strictly subterranean existence and consumes a high proportion of fibre in its diet. The fermentation chamber in these animals appears to absorb rather than generate heat and the temperature in it was consistently 1.2±0.5°C (n=17) lower than rectal temperature. A caecum with a lower temperature than its abdominal surrounds provides an internal heat sink which could be advantageous for metabolic heat dissipation in the plugged humid burrows in which the naked mole-rat permanently resides.Abbreviations RH relative humidity - T _b body temperature - T _c caecal temperature - T _i intraperitoneal temperature - T _r rectal temperature     

Evolution of aging: Testing the theory usingDrosophila

Evolutionary explanations of aging (or senescence) fall into two classes. First, organisms might have evolved the optimal life history, in which survival and fertility late in life are sacrificed for the sake of early reproduction or high pre-adult survival. Second, the life history might be depressed below this optimal compromise by the influx of deleterious mutations; since selection against late-acting mutations is weaker, deleterious mutations will impose a greater load on late life. We discuss ways in which these theories might be investigated and distinguished, with reference to experimental work withDrosophila. While genetic correlations between life history traits determine the immediate response to selection, they are hard to measure, and may not reflect the fundamental constraints on life history. Long term selection experiments are more likely to be informative. The third approach of using experimental manipulations suffers from some of the same problems as measures of genetic correlations; however, these two approaches may be fruitful when used together. The experimental results so far suggest that aging inDrosophila has evolved in part as a consequence of selection for an optimal life history, and in part as a result of accumulation of predominantly late-acting deleterious mutations. Quantification of these effects presents a major challenge for the future.     

Studies in the Capparaceae XXIII: Capparis coimbrana, a new species from Bolivia

Capparis coimbrana, a tree of the Bolivian and adjoining Brazilian subtropical to warm-temperate seasonal dry forests and savannas, is segregated fromC. petiolaris of the Pacific slope of Ecuador and northern Peru by its subcylindrical fruits (vs. spherical), white pulp (vs. yellow), sepals 3–5 mm (vs.1–3 mm), leaves with 13–24 (vs. 8–15) lateral veins per side, and by 1000 km of geographic isolation. The new species has edible fruits, but is not domesticated. The specific epithet celebrates Germán Coimbra S., eminent Bolivian ethnobotanist.

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Resumen   Capparis coimbrana es un árbol del bosque seco y sabanas subtropicales y cálidas de Bolivia y la parte adyacente de Brasil, segregada deCapparis petiolaris, que se encuentra distribuida en la región del Pacífico de Ecuador y norte de Perú, por sus frutos subcilíndricos (vs. esféricos), pulpa blanca (vs. amarilla), sépalos 3–5 mm (vs. 1–3 mm), hojas con 13–24 (vs. 8–15) pares de venas laterales, y aislada geográficamente 1000 km. Esta nueva especie posee frutos comestibles, pero no está domesticada. Su cpíteto específico honra a Germán Coimbra S., eminente etnobotánico boliviano.

     

Lipochemistry of the progamic stage of a self-incompatible species: Neutral lipids and fatty acids of the secretory stigma during its glandular activity,and of the solid style,the ovary and the anther in Forsythia intermedia Zab. (Heterostylic species)

Chromatographic (thin-layer, gas column, column chromatography) analyses of neutral lipids and fatty acids of reproductive tissues of Forsythia intermedia Zab., a self-incompatible species, were performed with two objectives in mind: 1. To determine whether there is a qualitative evolution of the different classes of lipids and fatty acids that could be correlated with the three functional stages observed during previous histochemical and ultrastructural studies. The stigmatic exudate and intracellular accumulations consist mainly of neutral lipids. 2. To compare the lipid composition of the stigma (both thrum and pin forms) with that of the style, the ovary, and the anther, and to investigate the possible existence of a stigma-specific lipid compound. Stigmatic neutral lipids are found mostly in a glyceridic mixture probably containing hydrocarbons and terpenes. The fatty acids identified are between C:7 and C: 12, with the maximum unsaturated form being a C: 18. During the secretory process there is no great qualitative diference between the neutral lipids and fatty acids found in the stigmas of thrum and pin forms. Sterols are present in styles, ovaries, and anthers, but not in stigmas. They represent the only difference in the lipid composition of these various floral structures.     

A phylogeny of Chinese species in the genus Phrynocephalus (Agamidae) inferred from mitochondrial DNA sequences

We investigated the phylogenetic relationships among most Chinese species of lizards in the genus Phrynocephalus (118 individuals collected from 56 populations of 14 well-defined species and several unidentified specimens) using four mitochondrial gene fragments (12S rRNA, 16S rRNA, cytochrome b, and ND4-tRNA(LEU)). The partition-homogeneity tests indicated that the combined dataset was homogeneous, and maximum-parsimony (MP), neighbor-joining (NJ), maximum-likelihood (ML) and Bayesian (BI) analyses were performed on this combined dataset (49 haplotypes including outgroups for 2058bp in total). The maximum-parsimony analysis resulted in 24 equally parsimonious trees, and their strict consensus tree shows that there are two major clades representing the Chinese Phrynocephalus species: the viviparous group (Clade A) and the oviparous group (Clade B). The trees derived from Bayesian, ML, and NJ analyses were topologically identical to the MP analysis except for the position of P. mystaceus. All analyses left the nodes for the oviparous group, the most basal clade within the oviparous group, and P. mystaceus unresolved. The phylogenies further suggest that the monophyly of the viviparous species may have resulted from vicariance, while recent dispersal may have been important in generating the pattern of variation among the oviparous species.     

Matelea sartago-diaboli, a new species of Apocynaceae: Asclepiadoideae from the inter-Andean dry valleys of Bolivia

Summary   Matelea sartago-diaboli is described from the Río Grande inter-Andean dry valley system of central Bolivia, and compared with the recently described Argentinian endemic M. calchaquina. The new species is illustrated, and its conservation status discussed.     

Neosartorya takakii, a new species from soil in Brazil

Among the isolates from soil of grassland in Roraima State, Brazil, a new species ofNeosartorya, N. takakii is described and illustrated.Neosartorya takakii differs from the other known species of the genus in having lenticular ascospores with two distinct equatorial crests and with roughly circularly arranged projections on the convex walls. A comparative SEM view of ascospores from six relatedNeosartorya species is also provided.     

CO2 alters water use,carbon gain,and yield for the dominant species in a natural grassland

Global atmospheric CO₂ is increasing at a rate of 1.5–2 ppm per year and is predicted to double by the end of the next century. Understanding how terrestrial ecosystems will respond in this changing environment is an important goal of current research. Here we present results from a field study of elevated CO₂ in a California annual grassland. Elevated CO₂ led to lower leaf-level stomatal conductance and transpiration (approximately 50%) and higher mid-day leaf water potentials (30–35%) in the most abundant species of the grassland, Avena barbata Brot. Higher CO₂ concentrations also resulted in greater midday photosynthetic rates (70% on average). The effects of CO₂ on stomatal conductance and leaf water potential decreased towards the end of the growing season, when Avena began to show signs of senescence. Water-use efficiency was approximately doubled in elevated CO₂, as estimated by instantaneous gas-exchange measurements and seasonal carbon isotope discrimination. Increases in CO₂ and photosynthesis resulted in more seeds per plant (30%) and taller and heavier plants (27% and 41%, respectively). Elevated CO₂ also reduced seed N concentrations (9%).     

Ceiba rubriflora (Malvaceae: Bombacoideae), a new species from Bahia, Brazil

Summary   Ceiba rubriflora Carv.-Sobr. & L. P. Queiroz, a new species of Malvaceae subfamily Bombacoideae from the State of Bahia, Brazil, is described and illustrated. It is considered to be endemic to calcareous outcrops in the valley of the Rio S?o Francisco, in the western region of the state. Notes on distribution, ecology and phenology are given. Relationships with related species are discussed and an addition to the key to species of Ceiba Mill. published by Gibbs & Semir (2003) are provided.     

Compensation of rodent pests after removal: control of two rat species in an irrigated farming system in the Red River Delta, Vietnam

Rodent pests have a strong capacity to recover rapidly from imposed reductions in abundance, but it is unclear how populations compensate to removal when farmers apply rodent control. The response of two rat species to rodent control was monitored using regular live-trapping in an irrigated lowland mixed rice agroecosystem. Rice field rats, Rattus argentiventer (52% of rodent captures), and lesser rice field rats, Rattus losea (29%), were removed using trap-barrier systems (TBS) at two sites while rice crops were present. The TBS was a plastic fence that enclosed a small field planted 3 weeks prior to the surrounding fields and set with multiple-capture cage-traps to capture rats that were attracted to the early-planted crop. Demographic responses of rats were compared to two untreated sites. There was a reduction in abundance of rodents on treated sites relative to untreated sites during the summer rice crop (by 45% and 28% for R. argentiventer and R. losea, respectively) an increase in abundance during the winter season (31% and 69%), and a mixed response during the spring rice crop (39% decrease and 41% increase). There was an increase in the proportion of juveniles captured on treated sites relative to untreated sites post-treatment (148% and 158%) and the body mass was lower on treated sites post-treatment (males: 13% and 41%; females: 22% and 22%). Older, larger animals were removed by the TBS and the rodent populations were compensating through high recruitment of young and high immigration into treated sites. No clear patterns were observed in the occurrence of adult breeding females for either R. argentiventer or R. losea. Rodent management, should therefore, occur over large areas (> 100 ha) to reduce the chance of reinvasion.     

Aechmea itapoana,a new species from Bahia (Brazil): Taxonomy and ecology

Aechmea itapoana is a new, conspicuous and distinct species from the coastal sand dune scrub of N.E. Brazil. Its possible relationships within subgenusChevaliera, toA. multiflora andA. rodriguesia are discussed.     

Emericella qinqixianii, a new species from desert soil in China

Emericella qinqixianii, a new species isolated from desert soil from Sanchakou, Aksu, Qiemo, Yuli, Yutian, and the Taklimakan desert 100 km inland from Minfeng, Xinjiang Province, China, is described and illustrated. It is characterized by grayish yellow to olive brown, non-ostiolate ascomata surrounded by hyaline to pale yellowish brown hülle cells, membranaceous peridium, prototunicate asci, and violet-brown, lenticular ascospores with two equatorial crests, smooth convex surfaces, and long filiform appendages. It hasAspergillus anamorph with biseriate aspergilla.     

Review: Implication of redox imbalance in animal health and performance at critical periods,insights from different farm species

The process of oxidative stress occurs all over the production chain of animals and food products. This review summarises insights obtained in different farm species (pigs, ruminants, poultry, and fishes) to underpin the most critical periods for the venue of oxidative stress, namely birth/hatching and weaning/start-feeding phase. Common responses between species are also unravelled in periods of high physiological demands when animals are facing dietary deficiencies in specific nutrients, suggesting that nutritional recommendations must consider the modulation of responses to oxidative stress for optimising production performance and quality of food products. These conditions concern challenges such as heat stress, social stress, and inflammation. The magnitude of the responses is partly dependent on the prior experience of the animals before the challenge, reinforcing the importance of nutrition and other management practices during early periods to promote the development of antioxidant reserves in the animal. When these practices also improved the performance and health of the animal, this further confirms the central role played by oxidative stress in physiologically and environmentally induced perturbations. Difficulties in interpreting responses to oxidative stress arise from the fact that the indicators are only partly shared between studies, and their modulations may also be challenge-specific. A consensus about the best indicators to assess pro-oxidative and antioxidant pathways is of huge demand to propose a synthetic index measurable in a non-invasive way and interpretable along the productive life of the animals.     

A new species of Phaeohelotium from Nothofagus forests in Argentina and Chile, with a key to the Southern Hemisphere species

Phaeohelotium nothofagi, sp.nov., found on fallen wood and leaves of Nothofagus dombeyi, is described and illustrated. The fungus is characterized by pale yellow discs, and fumose ascospores with asperulate walls. A key with distributional data for the five species of the genus now known in the Southern Hemisphere is provided.     

Review of the genusLimnichthys (Perciformes: Creediidae) from Japan, with description of a new species

A taxonomic review of Japanese species of the creediid genusLimnichthys recognised the following:L. fasciatus, L. nitidus (a senior synonym ofL. donaldsoni) andL. orientalis sp. nov.L. fasciatus has an antitropical distribution.L. orientalis sp. nov. differs from its most similar congener,L. nitidus, in having fewer scales above and below the lateral line (2 vs. 3) and the fifth pelvic fin ray shorter or absent, and in the shape of cirri on the lower jaw.     

Three new species and a new combination in the genusTorulomyces from soil

Seven isolates ofTorulomyces from Asian and Australian soil samples were studied in comparison with known taxa of the genus and withMonocillium indicum, the type species ofMonocillium. Three new species,Torulomyces parviverrucosus, T. laevis, andT. ovatus, are described, andT. brunneus is described as a new combination. Conidial characteristics, especially their shape and surface structure, are useful taxonomic criteria for distinguishing species ofTorulomyces. Monocillium is considered to be a distinct genus.     

Phoradendron olae Kuijt, a new species from Mexico pivotal in the taxonomy of the genus, with comments on P. californicum Nutt.

Materials are presented to the effect thatPhoradendron californicum Nutt., the nomenclatural type of the genusPhoradendron (Viscaceae), is related to southern, cataphyllous species, not to northern, acataphyllous ones. The evidence consists of the frequent occurrence of basal cataphylls in the species, variation in basal phyllotaxy, and a basically biseriate arrangement of flowers on fertile internodes. The suggestion of this southern, cataphyllous affinity is supported by the recent discovery of a strictly cataphyllous Mexican species,P. olae Kuijt, which shows median basal phyllotaxy and is in many features extremely similar toP. californicum. The nomenclatural consequences of this discovery would lead to subgen.Boreales (Trel.) Engler (and probably subgen.Aequatoriales (Trel.) Engler) being synonymized under subgen.Phoradendron, characterized by basal cataphylls (though not in all species). However, no generic subdivision of any sort is supported at this time.