A family of gamma-like calcium channel subunits

The gamma subunit was initially identified as an auxiliary subunit of the skeletal muscle calcium channel complex. Evidence for the existence of further gamma subunits arose following the characterization of a genetic defect that induces epileptic seizures in stargazer mice. We present here the first account of a family of at least five putative gamma subunits that are predominantly expressed in brain. The gamma-2 and gamma-4 subunits shift the steady-state inactivation curve to more hyperpolarized potentials upon coexpression with the P/Q type alpha(1A) subunit. The coexpression of the gamma-5 subunit accelerates the time course of current activation and inactivation of the alpha(1G) T-type calcium channel.     

Interpreting expression profiles of cancers by genome-wide survey of breadth of expression in normal tissues

A critical and difficult part of studying cancer with DNA microarrays is data interpretation. Besides the need for data analysis algorithms, integration of additional information about genes might be useful. We performed genome-wide expression profiling of 36 types of normal human tissues and identified 2503 tissue-specific genes. We then systematically studied the expression of these genes in cancers by reanalyzing a large collection of published DNA microarray datasets. We observed that the expression level of liver-specific genes in hepatocellular carcinoma (HCC) correlates with the clinically defined degree of tumor differentiation. Through unsupervised clustering of tissue-specific genes differentially expressed in tumors, we extracted expression patterns that are characteristic of individual cell types, uncovering differences in cell lineage among tumor subtypes. We were able to detect the expression signature of hepatocytes in HCC, neuron cells in medulloblastoma, glia cells in glioma, basal and luminal epithelial cells in breast tumors, and various cell types in lung cancer samples. We also demonstrated that tissue-specific expression signatures are useful in locating the origin of metastatic tumors. Our study shows that integration of each gene's breadth of expression (BOE) in normal tissues is important for biological interpretation of the expression profiles of cancers in terms of tumor differentiation, cell lineage, and metastasis.     

Sunfleck limits the small-scale distribution of endangered <Emphasis Type="Italic">Kingdonia uniflora</Emphasis> in the natural habitat of subalpine forest proved by its photosynthesis

The physiological effects of sunflecks on understory plants are poorly understood. Kingdonia uniflora is an endemic and endangered species in China, with a patchy distribution over much of its range. Sunflecks are reportedly the likely dominant factor in determining its patchy distribution. We studied the photosynthesis of K. uniflora in the field to test whether understory sunflecks result in photoinhibition and, thereby, potentially influence its patchy distribution. K. uniflora exhibited the low dark respiration rates, low light compensation points, and low light saturation points characteristic of shade-tolerant plants, allowing maintenance during the long periods of low understory light. Moreover, K. uniflora was able to regulate light energy utilization by non-photochemical quenching in low light. Gas exchange parameters were measured in six treatments (sunfleck-enriched, sunfleck-enriched with added saturation light, sunfleck-enriched with filtered ultraviolet-B (UV-B) radiation , sunfleck-limited, sunfleck-limited with added saturation light, and sunfleck-limited with filtered UV-B). The sunfleck-enriched treatment caused photoinhibition in K. uniflora, in part due to a UV-B-induced decrease in Pn. In addition, the application of simulated sunflecks indicated that K. uniflora leaves do not need continuous light. The photosynthetic responses of K. uniflora to sunflecks indicate that the sunflecks are a limiting factor in the small-scale distribution of K. uniflora.     

The EPSPS gene flow from glyphosate-resistant Brassica napus to untransgene B. napus and wild relative species Orychophragmus violaceus

Gene flow from transgenic plants to compatible wild relatives is one of the major impediments to the development of the culture of genetically engineered crop plants. In this work, the flow of EPSPS (conferring resistance to glyphosate) gene of transgene Brassica napus toward the untransgene B. napus and wild relative species Orychophragmus violaceus in an open field (1 ha) was studied. The data related to only the 2004 and 2005 autumn season on one location of southwest of China. Pollen dispersal and fertilization of the target plants were favored and a detailed analysis of the hybrid offspring was performed. In field, the data studied show that the gene flow frequency was 0.16% between GM and non-GM B. napus at a distance of 1 m from the transgenic donor area. The crosspollination frequency was 0.05% between GM and non-GM B. napus at a distance of 5 m from the transgenic donor area. At a distance of 10 m, no crosspollination was observed. According to the results of this study, B. napus transgene flow was low. However, the wild relative species O. violaceus could not be fertilized by the transgenic pollen of B. napus, no matter what the distance was.     

Electron microscopy holdings of the Protein Data Bank: the impact of the resolution revolution,new validation tools,and implications for the future

As a discipline, structural biology has been transformed by the three-dimensional electron microscopy (3DEM) “Resolution Revolution” made possible by convergence of robust cryo-preservation of vitrified biological materials, sample handling systems, and measurement stages operating a liquid nitrogen temperature, improvements in electron optics that preserve phase information at the atomic level, direct electron detectors (DEDs), high-speed computing with graphics processing units, and rapid advances in data acquisition and processing software. 3DEM structure information (atomic coordinates and related metadata) are archived in the open-access Protein Data Bank (PDB), which currently holds more than 11,000 3DEM structures of proteins and nucleic acids, and their complexes with one another and small-molecule ligands (~ 6% of the archive). Underlying experimental data (3DEM density maps and related metadata) are stored in the Electron Microscopy Data Bank (EMDB), which currently holds more than 21,000 3DEM density maps. After describing the history of the PDB and the Worldwide Protein Data Bank (wwPDB) partnership, which jointly manages both the PDB and EMDB archives, this review examines the origins of the resolution revolution and analyzes its impact on structural biology viewed through the lens of PDB holdings. Six areas of focus exemplifying the impact of 3DEM across the biosciences are discussed in detail (icosahedral viruses, ribosomes, integral membrane proteins, SARS-CoV-2 spike proteins, cryogenic electron tomography, and integrative structure determination combining 3DEM with complementary biophysical measurement techniques), followed by a review of 3DEM structure validation by the wwPDB that underscores the importance of community engagement.     

Cardiac mitochondrial ATP-sensitive potassium channel is activated by nitric oxide in vitro

Previous observations on the activation of the mitochondrial ATP-sensitive potassium channel (mitoK(ATP)) by nitric oxide (NO) in myocardial preconditioning were based on indirect evidence. In this study, we have investigated the direct effect of NO on the rat cardiac mitoK(ATP) after reconstitution of the inner mitochondrial membranes into lipid bilayers. We found that the mitoK(ATP) was activated by exogenous NO donor S-nitroso-N-acetyl penicillamine or PAPA NONOate. This activation was inhibited by mitoK(ATP) blockers 5-hydroxydecanoate or glibenclamide. Our observations confirm that NO can directly activate the cardiac mitoK(ATP), which may underlie its contribution to myocardial preconditioning.     

An arabinogalactan isolated from the stems of Cistanche deserticola induces the proliferation of cultured lymphocytes

A purified polysaccharide ACDP-2 was isolated from water extract of the stems of Cistanche deserticola. Chemical and spectroscopic analyses indicated that ACDP-2 is a highly branched arabinogalactan polymer that composes of linked d-galactopyranose and d-glucopyranose, which contains predominantly a branching point at the 6-carbon. The branched side-chains compose of terminal-, 1,5-, and 1,3,5-linked arabinofuranosyl residues. ACDP-2 showed an effect in stimulating the immune response, which when applied onto the cultured mouse lymphocytes induced the cell proliferation in a dose-dependent manner.     

Design Method of a Broadband Wide-Angle Plasmonic Absorber in the Visible Range

A new design method of a broadband wide-angle metal-dielectric-metal plasmonic absorber is presented based on the cavity mode theory. The broadband absorption is implemented by filling a unit cell with multi-size square metal patches resonant at adjacent wavelengths, with the widths of the patches and thickness of the dielectric layer optimized with the presented method. A broadband plasmonic absorber working in the visible range is designed, the absorption of which is insensitive to the azimuth angle of incident field and keeps over 0.7 at incident angle up to 60° for p polarization and above 0.6 at up to 40° for s polarization.