A simple and sensitive method for detection of pullulanase and isoamylase activities in polyacrylamide gels

Summary Pullulanase and isoamylase activities in PAGE bands have been detected and distinguished by using a two-step, replica-gel revealing assay. The de-branching activity is first revealed as a bluish-purple band by incubating an amylopectin-agar replica gel and then exposing this to iodine vapour. In the second step, pullulanase can be distinguished from isoamylase by a similar procedure using pullulan-agar replica gel and revealing hydrolysis by flooding the plate with ethanol; pullulanase activity shows a colorless band. The procedure exclude other amylases activities. The sensitivity is such that 0.0015 unit of pullulanase and 0.0004 unit of isoamylase activities can be detected easily.     

As if it weren’t hard enough already: Breaking down hiring discrimination following burnout

Hiring discrimination towards (former) burnout patients has been extensively documented in the literature. To tackle this problem, it is important to understand the underlying mechanisms of such unequal hiring opportunities. Therefore, we conducted a vignette experiment with 425 genuine recruiters and jointly tested the potential stigma against job candidates with a history of burnout that were mentioned earlier in the literature. We found candidates revealing a history of burnout elicit perceptions of requiring work adaptations, likely having more unpleasant collaborations with others as well as diminished health, autonomy, ability to work under pressure, leadership capacity, manageability, and learning ability, when compared to candidates with a comparable gap in working history due to physical injury. Led by perceptions of a reduced ability to work under pressure, the tested perceptions jointly explained over 90 % of the effect of revealing burnout on the probability of being invited to a job interview. In addition, the negative effect on interview probability of revealing burnout was stronger when the job vacancy required higher stress tolerance. In contrast, the negative impact of revealing burnout on interview probability appeared weaker when recruiters were women and when recruiters had previously had personal encounters with burnout.     

Cholinergic pyramidal neurons of the motor region of human neocortex

By means of histochemical methods for revealing +choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) cytoarchitectonic of the field 4 of the motor cortex of the cerebrum has been studied in 5 persons at the age of 33-65 years. An essential part of neurons at revealing AChE and most of them at revealing ChAT do not react. Among giant pyramidal neurons (Bets) according to ChAT activity, 4 types are distinguished: neurons with low, middle, high and very high activity. The presence of ChAT is ascertained in middle and large pyramidal neurons of the III layer. Presence of ChAT-positive synapses is demonstrated in apical dendrites. A conclusion is made that less part of the pyramidal in the III, V layers are cholinergic ones.     

Of rings and levers: the dynein motor comes of age

After nearly four decades of investigation, the dynein motor is finally on the verge of revealing its inner secrets. This multisubunit ATPase participates in several important microtubule-based motilities in eukaryotic cells. Numerous recent articles have advanced the understanding of the dynein motor substructure and its mechanism of force production, revealing both similarities to other motors and some surprises. We are now in a position to summarize a basic blueprint for dynein. At its core, the motor is a ring-shaped object with two protruding levers: one engages cargo and might provide much of the force for movement, and the other interacts with the microtubule track. The activities of both levers are linked through nucleotide-dependent conformational changes in the ring.     

Neural regulatory effects on the contractility of heart ventricles]

As a result of acute experiments on cats we revealed the approaches to choosing the best indices of the contractility of the left and the right cardiac ventricles in the concrete conditions of the experiment on the basis of the original criterion of optimality. For revealing neural inotropy influences we suggest the index based on the combined changes of optimum indices. A new approach to revealing reflex influences on contractility in the conditions of intact blood circulation is worked out, which is based on the comparison of these influences with the control changes of haemodynamic parameters.     

Raman optical activity and circular dichroism reveal dramatic differences in the influence of divalent copper and manganese ions on prion protein folding

The binding of divalent copper ions to the full-length recombinant murine prion protein PrP23-231 at neutral pH was studied using vibrational Raman optical activity (ROA) and ultraviolet circular dichroism (UV CD). The effect of the Cu2+ ions on PrP structure depends on whether they are added after refolding of the protein in water or are present during the refolding process. In the first case ROA reveals that the hydrated alpha-helix is lost, with UV CD revealing a drop from approximately 25% to approximately 18% in the total alpha-helix content. The lost alpha-helix could be that comprising residues 145-156, located within the region associated with scrapie PrP formation. In the second case, ROA reveals the protein's structure to be almost completely disordered/irregular, with UV CD revealing a drop in total alpha-helix content to approximately 5%. Hence, although Cu2+ binding takes place exclusively within the unfolded/disordered N-terminal region, it can profoundly affect the structure of the folded/alpha-helical C-terminal region. This is supported by the finding that refolding in the presence of Cu2+ of a mutant in which the first six histidines associated with copper binding to the N-terminal region are replaced by alanine has a similar alpha-helix content to the metal-free protein. In contrast, when the protein is refolded in the presence of divalent manganese ions, ROA indicates the alpha-helix is reinforced, with UV CD revealing an increase in total alpha-helix content to approximately 30%. The very different influence of Cu2+ and Mn2+ ions on prion protein structure may originate in the different stability constants and geometries of their complexes.     

The correlation between cellular size and protein expression levels--normalization for global protein profiling

An automated image analysis system was used for protein quantification of 1862 human proteins in 47 cancer cell lines and 12 clinical cell samples using cell microarrays and immunohistochemistry. The analysis suggests that most proteins are expressed in a cell size dependent manner, and that normalization is required for comparative protein quantification in order to correct for the inherent bias of cell size and systematic ambiguities associated with immunohistochemistry. Two reference standards were evaluated, and normalized protein expression values were found to allow for protein profiling across a panel of morphologically diverse cells, revealing putative patterns of over- and underexpression. Using this approach, proteins with stable expression as well as cell-line specific expression were identified. The results demonstrate the value of large-scale, automated proteome analysis using immunohistochemistry, in revealing functional correlations and establishing methods to interpret and mine proteomic data.     

The effect of pharmacologic substances on intraspecies aggression]

It is found, that aggression which occures in rats under inevitable painful stimulation is coursed as excessive excitation of the rats. This aggression may be used for revealing the sedative effect of drugs. The method of fighting for the stool which is caused by motivated fighting for the territory was worked out. This motivated aggression may be used for revealing the tranquillizing effect of drugs. Using these methods it is found that stelasine, haloperidol, amitriptyline, imipramine, chlordiazepoxide, diazepam and benactyzine in small doses have a tranquillizing effect, while pentobarbital and chlorpromazine have primarily a sedative effect.     

Trypanosoma cruzi: the effects of zinc supplementation during experimental infection

It is well recognized that zinc is an essential trace element, influencing growth and affecting the development and integrity of the immune system. The use of oligoelements as zinc can be considered a tool in modulating the effectiveness of the immune response. In this work zinc was daily and orally supplied in male Wistar rats infected with the Y strain of Trypanosoma cruzi. Parasitemia was evaluated and a significant reduction on blood parasites was observed. In order to check some immunological parameters peritoneal macrophages were counted revealing higher percentages for zinc supplied group. Consequently enhanced concentrations of IFN-gamma was found and for the first time NO was evaluated in T. cruzi infected animals under the influence of zinc therapy, revealing enhanced concentrations when compared to unsupplied counterparts. We conclude that zinc is able to up-regulate the host's immune response against parasite replication.     

Technique for Revealing the Three-Dimensional Architecture of Whole Preserved Spiculated Invertebrates

Procedures for revealing the three-dimensional arrangement of calcareous sclerites, spicules, or ossicles embedded within connective tissue in formalin fixed invertebrates are described. Spicules are stained with alizarin red S following maceration of preserved animals or colonies with either trypsin or KOH solutions. Connective tissue is stained with alcian blue in different samples prior to maceration. Stained animals or colonies are cleared in glycerin. This method for revealing spicular structure and arrangement and the gross morphology of connective tissues offers several advantages over either scanning electron microscopy or reconstruction from serial sections.     

Histological and histochemical study of rat salivary glands during their postnatal development

The postnatal development of the three major salivary glands (parotid, submaxillary and sublingual) was comparatively followed up from the histological viewpoint and in relation with some histochemical reactions. The sublingual gland presented a well developed cytomorphological structure at birth, whereas the parotid and the submaxillary one, immature at birth, gradually reached the overall appearance of adult glands, the former at 5 - 6 weeks, the latter at 8 weeks. In relation with the product secreted, it is already from birth that the parotid and the submaxillary glands presented negative reactions for mucosubstances and positive ones for revealing the protein-bound groups. The sublingual gland exhibited from the first postnatal 24 hrs positive reactions for revealing mucosubstances at the level of glandular secretory glands.     

A novel fold revealed by Mycobacterium tuberculosis NAD kinase, a key allosteric enzyme in NADP biosynthesis

NAD kinase catalyzes the magnesium-dependent phosphorylation of NAD, representing the sole source of freshly synthesized NADP in all organisms. The enzyme is essential for the growth of the deadly multidrug-resistant pathogen Mycobacterium tuberculosis and is an attractive target for novel antitubercular agents. The crystal structure of NAD kinase has been solved by multiwavelength anomalous dispersion at a resolution of 2.3 A in its T state. Two crystal forms have been obtained revealing either a dimer or a tetramer. The enzyme architecture discloses a novel molecular arrangement, with each subunit consisting of an alpha/beta N-terminal domain and a C-terminal 12-stranded beta sandwich domain, connected by swapped beta strands. The C-terminal domain shows a striking internal approximate 222 symmetry and an unprecedented topology, revealing a novel fold within the family of all beta structures. The catalytic site is located in the long crevice that defines the interface between the domains. The conserved GGDG structural fingerprint of the catalytic site is reminiscent of the related region in 6-phosphofructokinase, supporting the hypothesis that NAD kinase belongs to a newly reported superfamily of kinases.     

生态学的多样性指数:功能与系统发育

生物多样性是生态学的核心问题。传统的多样性指数仅包含物种数和相对多度的信息,这类基于分类学的多样性指数并不能很好地帮助理解群落构建和生态系统功能。不同物种对群落构建和生态系统功能所起到的作用类型和贡献也不完全相同,且物种在生态过程中的作用和贡献往往与性状密切相关,因此功能多样性已经成为反映物种群落构建、干扰以及环境因素对群落影响的重要指标。同时,由于亲缘关系相近的物种往往具有相似的性状,系统发育多样性也可以作为功能多样性的一个替代。功能多样性和系统发育多样性各自具有优缺点,但二者均比分类多样性更能揭示群落和生态系统的构建、维持与功能。     

Splitting pairs: the diverging fates of duplicated genes

Many genes are members of large families that have arisen during evolution through gene duplication events. Our increasing understanding of gene organization at the scale of whole genomes is revealing further evidence for the extensive retention of genes that arise during duplication events of various types. Duplication is thought to be an important means of providing a substrate on which evolution can work. An understanding of gene duplication and its resolution is crucial for revealing mechanisms of genetic redundancy. Here, we consider both the theoretical framework and the experimental evidence to explain the preservation of duplicated genes.     

Insights from the rat genome sequence

The availability of the rat genome sequence, and detailed three-way comparison of the rat, mouse and human genomes, is revealing a great deal about mammalian genome evolution. Together with recent developments in cloning technologies, this heralds an important phase in rat research.     

Virulence mechanisms of Gram-positive plant pathogenic bacteria

Actinobacteria and Firmicutes comprise a group of highly divergent prokaryotes known as Gram-positive bacteria, which are ancestral to Gram-negative bacteria. Comparative genomics is revealing that, though plant virulence genes are frequently located on plasmids or in laterally acquired gene clusters, they are rarely shared with Gram-negative bacterial plant pathogens and among Gram-positive genera. Gram-positive bacterial pathogens utilize a variety of virulence strategies to invade their plant hosts, including the production of phytotoxins to allow intracellular and intercellular replication, production of cytokinins to generate gall tissues for invasion, secretion of proteins to induce cankers and the utilization and manipulation of sap-feeding insects for introduction into the phloem sieve cells. Functional analysis of novel virulence genes utilized by Actinobacteria and Firmicutes is revealing how these ancient prokaryotes manipulate plant, and sometimes insect, metabolic processes for their own benefit.     

Evaluation of some methods for hybrid analysis, exemplified by hybridization in Argyrantheimim (Asteraceae)

A grouping of transformations is proposed: 1) "Element transformations", aimed at changing relations between elements within a single character vector; and 2) "vector transformations", aimed at changing relations between different character vectors. Logarithmic element transformation seemed suitable for revealing variation in size characters.
Principal coordinate analysis (PCO) was appropriate for determination of dimensionality and structural extremes (parentage). Due to polynomial distortions, however, variation in extreme populations was underestimated and variation in intermediate populations exaggerated.
A "character index", the mean of a specimen's ranged characters, is suggested to replace Anderson's hybrid index. Knowledge of parentage and parental maxima, but not of variation in pure parental populations, is required. The character index combined with modified Gay triangles was found suitable for revealing the structure of the material, which showed mainly one-dimensional variation. The material analysed comprised Argyranthemum broussonetü, A. frutescens , a hybrid swarm and experimental F₁ hybrids between these species; and A. sundingü , which was found to be a stabilized hybrid derivative, probably evolved by hybrid speciation with external barriers.     

Adrenergic and cholinergic innervation of the prostate in laboratory animals

The prostate innervation has been studied in 50 white rats, 12 rabbits, 12 guinea pigs, 6 cats and 6 dogs. Together with the impregnation techniques, Karnovsky-Roots method has been applied, for revealing cholinergic components, and the incubation method in 2% solution of glyoxylic acid, for revealing adrenergic nervous structures. Density of adrenergic and cholinergic nervous plexuses has been estimated by means of the planimetric point method. The prostate of the laboratory animals possesses well manifested adrenergic and cholinergic nervous plexuses. The organ's alveolus and ducts are covered with adrenergic and cholinergic fibers, however, the relative density of the cholinergic plexuses is less than that of the adrenergic ones. The guinea pig prostate is the most richly supplied with the adrenergic nervous plexuses, and the rabbit prostate--with the cholinergic nervous plexuses.     

Arabidopsis MAPKs: a complex signalling network involved in multiple biological processes

Many changes in environmental conditions and hormones are mediated by MAPK (mitogen-activated protein kinase) cascades in all eukaryotes, including plants. Studies of MAPK pathways in genetic model organisms are especially informative in revealing the molecular mechanisms by means of which MAPK cascades are controlled and modulate cellular processes. The present review highlights recent insights into MAPK-based signalling in Arabidopsis thaliana (thale cress), revealing the complexity and future challenges to understanding signal-transduction networks on a global scale.     

Prediction and analysis of protein palmitoylation sites

Palmitoylation is a universal and important lipid modification, involving a series of basic cellular processes, such as membrane trafficking, protein stability and protein aggregation. With the avalanche of new protein sequences generated in the post genomic era, it is highly desirable to develop computational methods for rapidly and effectively identifying the potential palmitoylation sites of uncharacterized proteins so as to timely provide useful information for revealing the mechanism of protein palmitoylation. By using the Incremental Feature Selection approach based on amino acid factors, conservation, disorder feature, and specific features of palmitoylation site, a new predictor named IFS-Palm was developed in this regard. The overall success rate thus achieved by jackknife test on a newly constructed benchmark dataset was 90.65%. It was shown via an in-depth analysis that palmitoylation was intimately correlated with the feature of the upstream residue directly adjacent to cysteine site as well as the conservation of amino acid cysteine. Meanwhile, the protein disorder region might also play an import role in the post-translational modification. These findings may provide useful insights for revealing the mechanisms of palmitoylation.