Effect of angiotensin converting enzyme (ACE) and angiotensins on human sperm functions

The presence of components of the renin angiotensin system (RAS) and specific receptors of angiotensin II in the female and male reproductive tract supports the hypothesis that reproductive functions may be controlled by RAS. Therefore, the present study investigated the influence of ACE and angiotensins on sperm functions and the sperm-egg interaction. The experiments did not indicate direct effects of ACE on the capacitation process or acrosome reaction. Release of ACE from human spermatozoa during capacitation was not related to their ability to undergo acrosome reaction after stimulation with ionophore. Therefore, ACE release does not seem to be a useful clinical marker for human sperm capacitation. However, decreased binding of human spermatozoa to the oolemma of zonafree hamster oocytes after inhibition of ACE by captopril indicates that kininase II is involved in sperm-egg interactions. In contrast to other studies, incubation with captopril had no influence on sperm binding to the zona pellucida. Because effects of ACE on sperm-egg interactions but not on capacitation or acrosome reaction were observed, several experiments were performed to study the influence of substrates and products on the acrosome reaction. Angiotensin II induced the acrosome reaction dose-dependently, whereas angiotensin I had no effect on the acrosome reaction. The effect of angiotensin II on acrosome reaction seems to be calcium-dependent and mediated by protein kinases. Since a specific type 2 angiotensin II receptor inhibits the acrosome reaction induced by angiotensin II, this subtype of receptors may be present at the surface of sperm heads. Another clue for the presence of type 2 receptors on human spermatozoa is the finding that pertussis toxin did not inhibit the angiotensin II induced acrosome reaction. In contrast to type 1 angiotensin II receptors, type 2 receptors are known to be G-protein independent.     

In vitro and in vivo digestibility of the albumin and globulin fractions of eight Brazilian cowpea [Vigna unguiculata (L) Walp] cultivars

Cowpea (Vigna unguiculata) is a very important crop for people living in the north‐east of Brazil where it constitutes the principal source of protein and carbohydrate. In this study, it was observed that the in vitro digestibility of the seed albumin and globulin fractions extracted from eight Brazilian cowpea cultivars was high when treated with pepsin but resistant to degradation by trypsin or chymotrypsin even after 3 h of treatment. When the albumin and globulin fractions were given to rats by intragastric intubation it was observed that intact proteins or their fragments were immunodetected in the faeces. Immunohistochemical analyses of the gut sections of these rats showed that a proportion of the albumin fraction (or its fragments), but not the globulin one, was bound to the brush border enterocytes in the duodenum. Thus the incomplete enzymatic degradation of both globulin and albumin fractions as well as the albumin binding to the gut may have a bearing upon the growth depression, malabsorption and diarrhoea observed on rats fed on cowpea seeds. Copyright © 2004 Society of Chemical Industry     

Predictors of change in postmerger identification during a merger process: A longitudinal study.

Adopting an intergroup perspective, the authors examined predictors of change in postmerger identification throughout a merger. Data were collected over 3 points of measurement from 157 students of a newly merged university. The 1st questionnaire was distributed 4 months after the implementation of the merger; the following 2 were distributed 6 months and 1 year thereafter. With its longitudinal design, this study replicates and extends past results by revealing predictors of change in organizational identification for members of the dominant and subordinate organizations throughout a merger process. As predicted, postmerger identification increased only slowly for members of both the dominant and the subordinate organizations. Multilevel models for change confirmed that the predictive effect of premerger identification on postmerger identification for members of the dominant organization dissipates over time. The effect of in-group typicality unexpectedly varied as a function of organizational membership and was stable over time. Perceived fairness in the merger process positively influenced postmerger identification across members of both organizations; over time the effect of fairness amplified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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Complexome Profiling: Assembly and Remodeling of Protein Complexes

Many proteins have been found to operate in a complex with various biomolecules such as proteins, nucleic acids, carbohydrates, or lipids. Protein complexes can be transient, stable or dynamic and their association is controlled under variable cellular conditions. Complexome profiling is a recently developed mass spectrometry-based method that combines mild separation techniques, native gel electrophoresis, and density gradient centrifugation with quantitative mass spectrometry to generate inventories of protein assemblies within a cell or subcellular fraction. This review summarizes applications of complexome profiling with respect to assembly ranging from single subunits to large macromolecular complexes, as well as their stability, and remodeling in health and disease.     

11‐Substituted Benzo[c]phenanthridines: New Structures and Insight into Their Mode of Antiproliferative Action

The synthesis of various new structures of a library of 11‐substituted 6‐amino‐11,12‐dihydrobenzo[c]phenanthridines (BP) and 11‐substituted 6‐aminobenzo[c]phenanthridines (BP‐D) is presented. These structures, further synthetic modifications, and the preparation of follow‐up products which delivered about 40 new derivatives are described. Their potential as antiproliferative drug candidates was investigated by comparison of NCI 60 developmental therapeutics program (DTP) human tumor cell line screening data based on the results of in vitro tumor cell growth inhibition, including about 40 hitherto unpublished compound test results with up to 60 cancer cell lines. NCI‐COMPARE studies helped to suggest the modes of action of the highly active antiproliferative drugs. These findings are supported by in vitro biological investigations showing either inhibition of tubulin polymerization and depolymerization or topoisomerase inhibition. Together with physicochemical parameters of the drug candidates, structure–activity relationships are critically discussed. Tubulin interaction or inhibition of topoisomerase I and IIα/β activity are two rationales that can explain the antiproliferative activity observed in the NCI 60 DTP human tumor cell line screen. However, it can also be reasonably assumed that these compounds address several targets, thus prohibiting the identification of simple structure–activity relationships. The new structures described herein are thought to act as so‐called multitarget drugs, thus being of special interest in the area of multidrug resistance.     

Genetic circuit building blocks for cellular computation,communications, and signal processing

In this paper, we review an emerging engineering discipline to programcell behaviors by embedding synthetic gene networks that performcomputation, communications, and signal processing. To accomplishthis goal, we begin with a genetic component library and a biocircuitdesign methodology for assembling these components into compoundcircuits. The main challenge in biocircuit design lies in selectingwell-matched genetic components that when coupled, reliably producethe desired behavior. We use simulation tools to guide circuitdesign, a process that consists of selecting the appropriatecomponents and genetically modifying existing components until thedesired behavior is achieved. In addition to such rational design, wealso employ directed evolution to optimize genetic circuitbehavior. Building on Nature's fundamental principle of evolution,this unique process directs cells to mutate their own DNA until theyfind gene network configurations that exhibit the desired systemcharacteristics. The integration of all the above capabilities infuture synthetic gene networks will enable cells to performsophisticated digital and analog computation, both asindividual entities and as part of larger cell communities. Thisengineering discipline and its associated tools will advance thecapabilities of genetic engineering, and allow us to harness cells fora myriad of applications not previously achievable.     

An approach for reverse engineering of design patterns

For the maintenance of software systems, developers have to completely understand the existing system. The usage of design patterns leads to benefits for new and young developers by enabling them to reuse the knowledge of their experienced colleagues. Design patterns can support a faster and better understanding of software systems. There are different approaches for supporting pattern recognition in existing systems by tools. They are evaluated by the Information Retrieval criteria precision and recall. An automated search based on structures has a highly positive influence on the manual validation of the results by developers. This validation of graphical structures is the most intuitive technique. In this paper a new approach for automated pattern search based on minimal key structures is presented. It is able to detect all patterns described by the GOF [15]. This approach is based on positive and negative search criteria for structures and is prototypically implemented using Rational Rose and Together.