The role of shaded cocoa plantations in the maintenance of epiphytic orchids and their interactions with phorophytes

生境丧失和破碎化是热带森林生物多样性的主要威胁。遮荫的可可种植园(SCP)等农业生态系统为热带森林生物群提供了庇护。然而,在这些转化后的生境中是否还维持种间生态的相互作用,目前尚鲜为人知。我们评定附生兰花群落的多样性、繁殖状态和光合代谢(CAM或C₃),以及与热带雨林(TRF)相比,它们与SCP中寄主树种(附生植物)之间的相互作用。在墨西哥东南部,对TRF和SCP中各三个采样地点进行研究。每个采样地点建立了4个400平方米的样地,调查记录所有兰花及其附生植物。我们依据花/果实(或残体)是否存在来确定每个兰花个体的繁殖(成体)或非繁殖(幼体)状态,并根据文献确定每种兰花的光合作用途径。我们采用真正的分集和生态网络的方法分别分析兰花的多样性以及兰科与附生植物间的相互作用。我们一共记录了47个兰花种的607个个体。在TRF (19个有效物种)中的兰花多样性高于SCP (11个有效物种),两个生境之间仅共享7个物种。SCP (53%)中的CAM兰花物种比TRF (14%)更常见。在群落水平上,SCP维持了非生殖兰花和生殖兰花的比例以及TRF兰科附生植物网络的嵌套结构和特异化水平。然而,SCP中仅保留一部分的TRF附生兰花,突显出保护TRF的重要性。尽管存在这种差异,诸如SCP类型的遮荫农业生态系统仍然可以维持天然林的一些多样性和功能,因为SCP附生兰花群落主要由CAM物种组成,其附生植物构成了一个嵌套的相互作用网络,对干扰形成了更强的抗性。     

PDZ/PDZ interaction between PSD‐95 and nNOS neuronal proteins

N‐Methyl‐D‐aspartate (NMDA) receptors are key components in synaptic communication and are highly relevant in central nervous disorders, where they trigger excessive calcium entry into the neuronal cells causing harmful overproduction of nitric oxide by the neuronal nitric oxide synthase (nNOS) protein. Remarkably, NMDA receptor activation is aided by a second protein, postsynaptic density of 95 kDa (PSD95), forming the ternary protein complex NMDA/PSD95/nNOS. To minimize the potential side effects derived from blocking this ternary complex or either of its protein components, a promising approach points to the disruption of the PSD‐95/nNOS interaction which is mediated by a PDZ/PDZ domain complex. Since the rational development of molecules targeting such protein‐protein interaction relies on energetic and structural information herein, we include a thermodynamic and structural analysis of the PSD95‐PDZ2/nNOS‐PDZ. Two energetically relevant events are structurally linked to a “two‐faced” or two areas of recognition between both domains. First, the assembly of a four‐stranded antiparallel β‐sheet between the β hairpins of nNOS and of PSD95‐PDZ2, mainly enthalpic in nature, contributes 80% to the affinity. Second, binding is entropically reinforced by the hydrophobic interaction between side chains of the same nNOS β‐hairpin with the side chains of α2‐helix at the binding site of PSD95‐PDZ2, contributing the remaining 20% of the total affinity. These results suggest strategies for the future rational design of molecules able to disrupt this complex and constitute the first exhaustive thermodynamic analysis of a PDZ/PDZ interaction.     

RCSB Protein Data Bank: Enabling biomedical research and drug discovery

Analyses of publicly available structural data reveal interesting insights into the impact of the three‐dimensional (3D) structures of protein targets important for discovery of new drugs (e.g., G‐protein‐coupled receptors, voltage‐gated ion channels, ligand‐gated ion channels, transporters, and E3 ubiquitin ligases). The Protein Data Bank (PDB) archive currently holds > 155,000 atomic‐level 3D structures of biomolecules experimentally determined using crystallography, nuclear magnetic resonance spectroscopy, and electron microscopy. The PDB was established in 1971 as the first open‐access, digital‐data resource in biology, and is now managed by the Worldwide PDB partnership (wwPDB; wwPDB.org ). US PDB operations are the responsibility of the Research Collaboratory for Structural Bioinformatics PDB (RCSB PDB). The RCSB PDB serves millions of RCSB.org users worldwide by delivering PDB data integrated with ～40 external biodata resources, providing rich structural views of fundamental biology, biomedicine, and energy sciences. Recently published work showed that the PDB archival holdings facilitated discovery of ～90% of the 210 new drugs approved by the US Food and Drug Administration 2010–2016. We review user‐driven development of RCSB PDB services, examine growth of the PDB archive in terms of size and complexity, and present examples and opportunities for structure‐guided drug discovery for challenging targets (e.g., integral membrane proteins).     

Reconstruction of the absorption spectrum of Synechocystis sp. PCC 6803 optical mutants from the in vivo signature of individual pigments

Photosynthesis Research - In this work, we reconstructed the absorption spectrum of different Synechocystis sp. PCC 6803 optical strains by summing the computed signature of all pigments present in...     

Follicular growth and sex steroids in adult females of the endemic Amazonian freshwater stingray Potamotrygon wallacei (Chondrichthyes,Potamotrygonidae)

Environmental Biology of Fishes - This study evaluated how the plasma steroid hormones testosterone (T) and 17β-estradiol (E2) are related to follicular development in regenerating females of...     

Conventional single-chamber pacemakers versus transcatheter pacing systems in a “real world” cohort of patients: A comparative prospective single-center study

PurposeDespite the developments in conventional transvenous pacemakers (VVI-PM), the procedure is still associated with significant complications. Although there are no prospective clinical trials that compared VVI-PM with transcatheter pacemaker systems (TPS).MethodsThis is a prospective, observational, single-center study that included all patients with an indication for a single-chamber pacemaker implant within a 4-year period. All clinical, ECG and echocardiographic characteristics at implant, electrical parameters, associated complications and mortality were analyzed. A Cox survival model and a Bayesian cohort analysis were performed for differences in complication rates between groups.ResultsThere were 443 patients included (198 TPS and 245 VVI-PM). The mean age was 81.5 years (TPS group, 79.2 ± 6.6 years; VVI-PM group, 83.5 ± 8.9 years). There was a male predominance in TPS group (123, 62.1% vs. 67, 27.3%; p < 0.001). The presence of systolic dysfunction and renal insufficiency were more frequent in VVI-PM group than in TPS patients. Mean follow-up was 22.3 ± 15.9 months. In a multivariable paired data the TPS group presented fewer complications than VVI-PM group (HR = 0.39 [0.15–0.98], p-value 0.013), but major complications were not different (6, 3% vs 14, 5.6% respectively, p = 0.1761). There was no difference in the mortality rate between the groups. The TPS group had less risk than VVI-PM group to have a complication, with a 96% of probability.ConclusionsTPS patients had a lower overall complication rate than VVI-PM patients including matched-pair samples using a Bayesian analysis. These results confirm the safety profile of TPS in clinical practice.