Dominant inheritance and intra�Cfamilial variations in the association of Sturge�CWeber and Klippel�CTrenaunay�CWeber syndromes

This case report shows a genealogical study where a woman has limb hypertrophy and her son has an association of Sturge–Weber syndrome with Klippel–Trenaunay–Weber syndrome. The Sturge–Weber and Klippel–Trenaunay–Weber syndromes appear to be different manifestations of the same affliction. Familial aggregation exists and transmission may be almost imperceptible between generations. Identification of minor manifestations may prove to be a valuable contribution to genetic counseling of families and the prevention of new cases.     

Karyotype variability in species of the genus Zephyranthes Herb. (Amaryllidaceae�CHippeastreae)

In this work, the cytotaxonomic implications of the chromosomal characterization of cultivated and native Zephyranthes species described in northeastern Brazil were studied. All individuals had karyotype formed by a set of metacentric chromosomes, in addition to submetacentric and acrocentric chromosomes. In Zephyranthes robusta, 2n?=?12 was observed and karyotype with formula?4M?+?2SM in somatic cells, representing the most symmetric karyotype among the investigated species. Z.?sylvatica showed three different chromosome complement numbers: 2n?=?12 with formula?1M?+?5SM, 2n?=?12?+?1B with 1M?+?5SM?+?(1B), and 2n?=?18 formed by cracks. The cultivated species Z.?rosea Lindl. presented 2n?=?24 with 4M?+?7SM?+?1A, however Z.?grandiflora Lindl. showed the same chromosome number with 2M?+?5SM?+?5A. Zephyranthes aff. rosea Lindl. presented 2n?=?25 with one small metacentric forming a crack in the fourth metacentric pair. Z.?brachyandra has 2n?=?24?+?(1B) and formula?4M?+?3SM?+?5A?+?(1B). Z.?candida Herb. presented 2n?=?38 and karyotype formula?9M?+?10SM. In Habranthus itaobinus numerical variation was observed, with the majority of populations showing a chromosome complement composed of 2n?=?44?+?1B with 5M?+?12SM?+?5A?+?(1B), or 2n?=?44?+?3B in a single population. Mechanisms involved in the formation of these karyotypes from chromosomal imbalance data are discussed. Taken together, data from this study only partially confirm previous counts for epithets and further enhance the cytological variability data previously reported for the genus.     

Land�CWater interactions in the amazon

Biogeochemistry is hosting this special thematic issue devoted to studies of land?Cwater interactions, as part of the Large-scale Biosphere?CAtmosphere Experiment in Amazônia (LBA). This compilation of papers covers a broad range of topics with a common theme of coupling land and water processes, across pristine and impacted systems. Findings highlighted that hydrologic flowpaths are clearly important across basin size and structure in determining how water and solutes reach streams. Land-use changes have pronounced impacts on flowpaths, and subsequently, on stream chemistry, from small streams to large rivers. Carbon is produced and transformed across a broad array of fluvial environments and wetlands. Surface waters are not only driven by, but provide feedback to, the atmosphere.     

Host�Cpathogen coevolution in human tuberculosis

Tuberculosis (TB) is a disease of antiquity. Yet TB today still causes more adult deaths than any other single infectious disease. Recent studies show that contrary to the common view postulating an animal origin for TB, Mycobacterium tuberculosis complex (MTBC), the causative agent of TB, emerged as a human pathogen in Africa and colonized the world accompanying the Out-of-Africa migrations of modern humans. More recently, evolutionarily ‘modern’ lineages of MTBC expanded as a consequence of the global human population increase, and spread throughout the world following waves of exploration, trade and conquest. While epidemiological data suggest that the different phylogenetic lineages of MTBC might have adapted to different human populations, overall, the phylogenetically ‘modern’ MTBC lineages are more successful in terms of their geographical spread compared with the ‘ancient’ lineages. Interestingly, the global success of ‘modern’ MTBC correlates with a hypo-inflammatory phenotype in macrophages, possibly reflecting higher virulence, and a shorter latency in humans. Finally, various human genetic variants have been associated with different MTBC lineages, suggesting an interaction between human genetic diversity and MTBC variation. In summary, the biology and the epidemiology of human TB have been shaped by the long-standing association between MTBC and its human host.     

Effect of Acupuncture on Hypothalamic�CPituitary�CAdrenal System in Maternal Separation Rats

The maternal separation (MS) animal model has been widely used to study early life stress and several psychiatric conditions such as depression and anxiety. In this study, we investigated the effect of acupuncture on anxiety-related behaviors and hypothalamic-pituitary-adrenal (HPA) system in MS-induced early life stress of Sprague-Dawley rat pups (14-21 postnatal days). For determining anxiety-related behaviors, the elevated plus-maze test was performed. The effects of acupuncture on the activation of stress were measured by assessing plasma levels of corticosterone (CORT) and adrenocorticotropin hormone (ACTH). The hypothalamic immunoreactivity (IR) of arginine vasopressin (AVP) was also examined. Acupuncture was conducted at acupoint HT7, which is used to treat mental disorders in Oriental medicine, for seven consecutive days. Acupuncture significantly decreased the frequencies of open arm entries and the amount of time spent in the open arms in MS rats. In addition, acupuncture reduced CORT and ACTH levels in plasma of MS rats, and AVP-IR in the hypothalamic paraventricular nucleus of MS rats. In conclusion, acupuncture reduced anxiety-related behaviors and modulated the HPA system. These findings suggest that acupuncture at HT7 may be useful as a therapeutic treatment in MS-induced early life stress.     

Effect of Selenium on Ascorbate�CGlutathione Metabolism During PEG-induced Water Deficit in Trifolium repens L.

To elucidate the effect of selenium (Se) on the ascorbate?Cglutathione (ASC?CGSH) cycle under drought stress, the activities of antioxidant enzymes and the levels of molecules involved in ASC?CGSH metabolism were studied in Trifolium repens seedlings subjected to polyethylene glycol (PEG)-induced water deficit alone or combined with 5???M Na₂SeO₄. Compared to the control, H₂O₂, thiobarbituric acid reactive substances (TBARS), ascorbate (ASC), dehydroascorbate (DHA), and glutathione disulfide (GSSG) contents increased, whereas a constant content of glutathione (GSH) and decreases in ASC/DHA and GSH/GSSG ratios were observed in the presence of PEG. The activities of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) were upregulated, except for monodehydroascorbate reductase (MDHAR) activity during PEG-induced water deficit. Se application decreased the contents of H₂O₂, TBARS, DHA, and GSSG, increased the levels of GSH and ASC, and inhibited the decreases of ASC/DHA and GSH/GSSG ratios. Although it did not affect APX activity significantly, Se addition improved the activities of MDHAR, DHAR, and GR. Furthermore, GR activity showed the highest increase followed by that of DHAR and MDHAR in decreasing order. These data indicated that fluctuations in ASC?CGSH metabolism resulting from Se may have a positive effect on drought stress mitigation, and the regulation in the ASC?CGSH cycle can be attributed mainly to GR and DHAR in PEG?+?Se-treated T. repens seedlings.     

Physical�Cchemical determinants of coil conformations in globular proteins

We present a method with the potential to generate a library of coil segments from first principles. Proteins are built from α‐helices and/or β‐strands interconnected by these coil segments. Here, we investigate the conformational determinants of short coil segments, with particular emphasis on chain turns. Toward this goal, we extracted a comprehensive set of two‐, three‐, and four‐residue turns from X‐ray–elucidated proteins and classified them by conformation. A remarkably small number of unique conformers account for most of this experimentally determined set, whereas remaining members span a large number of rare conformers, many occurring only once in the entire protein database. Factors determining conformation were identified via Metropolis Monte Carlo simulations devised to test the effectiveness of various energy terms. Simulated structures were validated by comparison to experimental counterparts. After filtering rare conformers, we found that 98% of the remaining experimentally determined turn population could be reproduced by applying a hydrogen bond energy term to an exhaustively generated ensemble of clash‐free conformers in which no backbone polar group lacks a hydrogen‐bond partner. Further, at least 90% of longer coil segments, ranging from 5‐ to 20 residues, were found to be structural composites of these shorter primitives. These results are pertinent to protein structure prediction, where approaches can be divided into either empirical or ab initio methods. Empirical methods use database‐derived information; ab initio methods rely on physical–chemical principles exclusively. Replacing the database‐derived coil library with one generated from first principles would transform any empirically based method into its corresponding ab initio homologue.     

Cloud streets and land�Cwater interactions in the Amazon

Cloud streets are common feature in the Amazon Basin. They form from the combination of the vertical trade wind stress and moist convection. Here, satellite imagery, data collected during the COBRA-PARÁ (Caxiuanã Observations in the Biosphere, River and Atmosphere of Pará) field campaign, and high resolution modeling are used to understand the streets?? formation and behavior. The observations show that the streets have an aspect ratio of about 3.5 and they reach their maximum activity around 15:00 UTC when the wind shear is weaker, and the convective boundary layer reaches its maximum height. The simulations reveal that the cloud streets onset is caused by the local circulations and convection produced at the interfaces between forest and rivers of the Amazon. The satellite data and modeling show that the large rivers anchor the cloud streets producing a quasi-stationary horizontal pattern. The streets are associated with horizontal roll vortices parallel to the mean flow that organizes the turbulence causing advection of latent heat flux towards the upward branches. The streets have multiple warm plumes that promote a connection between the rolls. These spatial patterns allow fundamental insights on the interpretation of the Amazon exchanges between surface and atmosphere with important consequences for the climate change understanding.     

Clonal Differences in Photosynthesis in Hevea Brasiliensis Müll. Arg.

The objective of the present investigation was to examine the extent of variations in single leaf net photosynthetic rate (P_N) and its relative dependence on stomatal conductance (g_s) and the mesophyll capacity to fix carbon in 12 clones of the natural rubber plant. There were significant variations in P_N measured at low and saturating photon flux density (PFD); the extent of variation was larger at low than at saturating PFD. The compensation irradiance (CI) and apparent quantum yield of CO₂ assimilation (φ_c) calculated from the P_N/PFD response curves showed significant variations among the clones. P_N at low irradiance was positively correlated with φ_c. Thus a clone with large P_N at low irradiance, high φ_c, and low CI may tolerate shade better and thus produce a high tree stand per hectare. A strong positive correlation existed between P_N saturated with radiant energy (P_sat) and carboxylation efficiency (CE) estimated from the response curves of P_N on intercellular CO₂ concentration (C_i), but g_s showed a poor correlation with P_sat High CO₂ compensation concentration (Γ) led to low CE in Hevea clones. A clone with large P_sat, high CE, low g_s, and low Γ is the one in which photosynthesis is more dependent on the mesophyll factors than stomata. Such a clone may produce relatively high biomass and maintain high water use efficiency. This revised version was published online in September 2006 with corrections to the Cover Date.     

Arbuscular mycorrhizal mediation of biomass�Cdensity relationship of Medicago sativa L. under two water conditions in a field experiment

The biomass–density relationship (whereby the biomass of individual plants decreases as plant density increases) has generally been explained by competition for resources. Arbuscular mycorrhizal fungi (AMF) are able to affect plant interactions by mediating resource utilization, but whether this AMF-mediated interaction will change the biomass–density relationship is unclear. We conducted an experiment to test the hypothesis that AMF will shift the biomass–density relationship by affecting intraspecific competition. Four population densities (10, 100, 1,000, or 10,000 seedlings per square meter) of Medicago sativa L. were planted in field plots. Water application (1,435 or 327.7 mm/year) simulated precipitation in wet areas (sufficient water) and arid areas (insufficient water). The fungicide benomyl was applied to suppress AMF in some plots (“low-AMF” treatment) and not in others (“high-AMF” treatment). The effect of the AMF treatment on the biomass–density relationship depended on water conditions. High AMF enhanced the decrease of individual biomass with increasing density (the biomass–density line had a steeper slope) when water was sufficient but not when water was insufficient. AMF treatment did not affect plant survival rate or population size but did affect absolute competition intensity (ACI). When water was sufficient, ACI was significantly higher in the high-AMF treatment than in the low-AMF treatment, but ACI was unaffected by AMF treatment when water was insufficient. Our results suggest that AMF status did not impact survival rate and population size but did shift the biomass–density relationship via effects on intraspecific competition. This effect of AMF on the biomass–density relationship depended on the availability of water.