Arylazido-beta-alanine ADP-ribose, a novel irreversible competitive inhibitor of mitochondrial NADH-ubiquinone reductase.

Arylazido-beta-alanine ADP-ribose, a photoreactive analogue of ADP-ribose, was synthesized. In the dark, arylazido-beta-alanine ADP-ribose acts as a competitive reversible inhibitor of mitochondrial NADH-ubiquinone reductase with a K(i) of 37 microM. Upon photolysis, arylazido-beta-alanine ADP-ribose is converted to a potent irreversible active site-directed inhibitor of the enzyme. Photo-induced inhibition of membrane-bound NADH-ubiquinone reductase by arylazido-beta-alanine ADP-ribose is incomplete and results in a 20-fold reduction of the NADH oxidase and 2.5-fold reduction of the energy-dependent NAD(+) reductase activities. The arylazido-beta-alanine ADP-ribose resistant activities (direct and reverse) of the enzyme are characterized by a two orders of magnitude lower affinity to the corresponding substrates compared to those of the uninhibited NADH-ubiquinone reductase. A different kinetic behavior of the inhibited and native enzyme can be explained by invoking the two catalytically competent nucleotide-binding sites model of NADH-ubiquinone reductase.     

First finding of <Emphasis Type="Italic">Melamphaes pachystomus</Emphasis> (Melamphaidae) in the northeastern part of the Pacific Ocean

The first finding of the rare species Melamphaes pachystomus in the northeastern part of the Pacific Ocean is reported. The species has been previously known only by the type series (three specimens in total) from the southeastern part of this ocean. Our new finding substantially contributes to the knowledge of its habitat.     

Intracoronary endothelin-1 infusion combined with systemic isoproterenol treatment: antagonistic arrhythmogenic effects

Endothelin-1 secretion and sympathetic activation may play important role in cardiovascular pathophysiology. In vivo interactions between these systems are not defined. We aimed to study the electrophysiological and haemodynamic effects of simultaneous intracoronary endothelin-1 and intravenous isoproterenol infusions. 18 anaesthetised open chest dogs were studied after AV-ablation. Mean arterial blood pressure, coronary blood flow, left ventricular contractility, standard electrocardiograms, right and left ventricular epi- and endocardial monophasic action potential (MAP) signals were recorded. Intracoronary endothelin-1 (30 pmol/min) was given to Group ET (n=6), intravenous isoproterenol (0.2 microg/kg/min) to Group ISO (n=6), both endothelin-1 and isoproterenol to Group ET+ISO (n=6) for 30 min. MAP duration increased in all studied regions of Group ET, decreased in all studied regions of Group ISO and ET+ISO (control vs. maximal changes of left ventricular epicardial MAP 90% duration, Group ET: 296+/-22 vs 369+/-20 ms, p<0.05, Group ISO: 298+/-18 vs 230+/-27 ms, p<0.01, Group ET+ISO: 302+/-18 vs 231+/-10 ms, p<0.01). In Group ET, early after depolarisations (3/6), polymorphic non-sustained ventricular tachycardias (6/6), and ventricular fibrillation (3/6) could be observed. In Group ISO, monomorphic non-sustained ventricular tachycardias (5/6) and atrial fibrillation (3/6) appeared. In Group ET+ISO, mono- and polymorphic non-sustained ventricular tachycardias occurred (5/6), neither ventricular fibrillation nor atrial fibrillation developed. An additive effect of endothelin-1 and isoproterenol on left ventricular contractility was observed. Isoproterenol treatment showed antagonistic effect against endothelin-1 induced MAP duration prolongation, early after depolarisation and ventricular fibrillation formation, while endothelin-1 showed protective effect against the development of isoproterenol induced atrial fibrillation.     

Transformation of the afferent tactile signal into a motor command in the cat motor cortex

Activity of 112 neurons of the precruciate motor cortex in cats was studied during a forelimb placing reaction to tactile stimulation of its distal parts. The latent period of response of the limb to tactile stimulation was: for flexors of the elbow (biceps brachii) 30–40 msec, for the earliest reponses of cortical motor neurons about 20 msec. The biceps response was observed 5–10 msec after the end of stimulation of the cortex with a series of pulses lasting 25 msec. Two types of excitatory responses of the neurons were identified: responses of sensory type observed to each tactile stimulation of the limb and independent of the presence or absence of motion, and responses of motor type, which developed parallel with the motor response of the limb and were not observed in the absence of motion. The minimal latent period of the responses of motor type was equal to the latent period of the sensory responses to tactile stimulation (20±10 msec). Stimulation of the cortex through the recording microelectrode at the site of derivation of unit activity, which increased during active flexion of the forelimb at the elbow (11 stimuli at intervals of 2.5 msec, current not exceeding 25 µA), in 70% of cases evoked an electrical response in the flexor muscle of the elbow.M. V. Lomonosov Moscow State University. Translated from Neirofiziologiya, Vol. 9, No. 2, pp. 115–123, March–April, 1977.     

Structure of male accessory glands of Bolivarius siculus (fischer) (Orthoptera,Tettigoniidae) and protein analysis of their secretions

In Tettigoniidae (Orthoptera), male reproductive accessory glands are involved in the construction of a two‐part spermatophore; one part, the spermatophylax, is devoid of sperm and considered a nuptial gift. The morphology, ultrastructure, and secretion protein content of the male reproductive accessory glands from Bolivarius siculus were investigated. Two main groups of gland tubules open into the ejaculatory duct: the “first‐order” glands, a number of large anterior tubules, and the “second‐order” glands, smaller and more numerous tubules positioned posteriorly. Along with a further subdivision of the gland tubules, we here describe for the first time an additional gland group, the intermediate tubules, which open between first and second‐order glands. The mesoderm‐derived epithelium of all glands is a single layer of microvillated cells, which can be either flattened or cylindric in the proximal or distal region of the same gland. Epithelial cells, very rich in RER and Golgi systems, produce secretions of both electron‐dense granules and globules or electron‐transparent material, discharged into the gland lumen by apocrine or merocrine mechanisms, respectively. With one exception, a unique electrophoresis protein profile was displayed by each of the gland types, paralleling their unique morphologies. To assess the contribution of different types of accessory glands to the construction of the spermatophore, the protein patterns of the gland secretions were compared with those of the extracts from the two parts of the spermatophore. All samples showed bands distributed in a wide range of molecular weight, including proteins of very low molecular mass. However, one major high molecular weight protein band (>180 kDa) is seen exclusively in extracts from the first‐order glands, and corresponds to an important protein component of the spermatophylax. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.     

Effects of the Diet on the Microbiota of the Red Palm Weevil (Coleoptera: Dryophthoridae)

Rhynchophorus ferrugineus, also known as the red palm weevil, is regarded as the major pest of palm trees. Although studies of the microbiota associated with this species have been performed in recent years, little attention has been dedicated to the influence of the diet in shaping the host bacterial community. Here, we investigated the influence of food sources (i.e. palm tissues vs apple based substrate) on the microbial diversity associated with RPW, which was compared with the microbiota associated with wild individuals of the sister species Rhynchophorus vulneratus. The bacterial characterization was performed using a culture independent approach, i.e. the 16S rRNA pyrotag, and a culture dependent approach for a subset of the samples, in order to obtain bacterial isolates from RPW tissues. The bacterial community appeared significantly influenced by diet. Proteobacteria resulted to be the most abundant clade and was present in all the specimens of the three examined weevil groups. Within Proteobacteria, Enterobacteriaceae were identified in all the organs analysed, including hemolymph and reproductive organs. The apple-fed RPWs and the wild R. vulneratus showed a second dominant taxon within Firmicutes that was scarcely present in the microbiota associated with palm-fed RPWs. A comparative analysis on the bacteria associated with the palm tissues highlighted that 12 bacterial genera out of the 13 identified in the plant tissues were also present in weevils, thus indicating that palm tissues may present a source for bacterial acquisition.