Coronary sinus of the heart in various anomalies of the conotruncus

Thirty-one hearts with anomalous conotruncus (common arterial trunk, hypoplasia of the aorta with transposition, atresia of the pulmonary trunk) have been studied. There are some peculiarities in anatomy and topography of the coronary sinus, concerning its sources, that is veins forming the venous sinus, position and interrelations with the venous sulcus and with the interatrial septum, size and form of the ostium and valve of the coronary sinus. The most amount of the anatomical peculiarities of the sinus are observed in the preparations, where the anomalous conotruncus is combined with absence of one or both cardiac septa.     

A Java-based tool for the design of classification microarrays

Background  

Classification microarrays are used for purposes such as identifying strains of bacteria and determining genetic relationships to understand the epidemiology of an infectious disease. For these cases, mixed microarrays, which are composed of DNA from more than one organism, are more effective than conventional microarrays composed of DNA from a single organism. Selection of probes is a key factor in designing successful mixed microarrays because redundant sequences are inefficient and limited representation of diversity can restrict application of the microarray. We have developed a Java-based software tool, called PLASMID, for use in selecting the minimum set of probe sequences needed to classify different groups of plasmids or bacteria.     

Hornet cuticle-a composite structure comprised of a series of duplex lamellae attenuating toward the interior of the body

Our study deals with the ultramicroscopic structure of the yellow pigmented cuticular stripes on the abdomen of the oriental hornet Vespa orientalis (Hymenoptera, Vespinae). The abdominal cuticle is composed of numerous (more than 25) lamellae which progressively attenuate as one proceeds from the outside interiorly. On a logarithmic scale the pattern of lamellar attenuation is a linear drop to almost asymptotic thickness with the innermost lamellae at least one order of magnitude less than that of the outermost one and describable by a mathematic equation. Each lamella is a composite structure consisting of two primary elements, namely, a skeleton and filling material. The skeleton is composed of chitin and comprised of parallel ‘plates’ which visibly separate between the lamellae. These ‘plates’ are interconnected by: (1) perpendicular ‘pillars’ which are distributed intermittently at more or less uniform intervals; and (2) by a layer of chitin shaped like a horizontal helix or at times even a double helix whose diameter equals the distance between two successive lamellae. In the space within the skeletal element there is a filling material of variable nature, mostly proteinaceous, which dissolves out and vacates the cuticle during its processing for microscopic observation, leaving behind the skeletal element. Such structure of the cuticle, wherein two different materials combine serially into one duplex structure is typical of composite materials. This duplex structuring of the lamellae, combined with their gradual attenuation and compacting towards the interior, lends the cuticle in the abdominal region the shape of a thin-walled laminated beam endowed with a wide array of mechanical, thermal, electric, optic, acoustic and probably numerous other properties which render the cuticle efficient for multiple purposes.     

Discrete limbal epithelial stem cell populations mediate corneal homeostasis and wound healing

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Newly Synthesized and Preformed Acetylcholine Are Released from Torpedo Synaptosomes by Different Pathways

In this study, we investigated the mechanisms underlying the release of preformed and of newly synthesized acetylcholine (ACh) from isolated Torpedo nerve terminals (synaptosomes). This was pursued by examining and comparing the effects of anticytoskeletal and anticalmodulin drugs and of activating the presynaptic muscarinic ACh receptors on the release of preformed endogenous ACh and of newly synthesized radiolabeled ACh. The anticytoskeletal drugs vinblastine, cytochalasin B, and colchicine inhibit the Ca2+-dependent K+-mediated release of newly synthesized radiolabeled ACh, but have no effect on the release of preformed ACh. By contrast, the muscarinic agonist oxotremorine markedly inhibits the release of preformed ACh, but has little effect on the release of newly formed ACh. Treatment of the synaptosomes with the calmodulin antagonist trifluoperazine inhibits the release of both ACh pools concomitantly. These findings show that preformed and newly synthesized ACh are released by different routes and suggest that their secretion is mediated by converging pathways. The significance of these results in view of the previously demonstrated preferential release of newly synthesized ACh is discussed.     

Bi-directional electron transfer between H2 and NADPH mitigates light fluctuation responses in green algae

The metabolism of green algae has been the focus of much research over the last century. These photosynthetic organisms can thrive under various conditions and adapt quickly to changing environments by concomitant usage of several metabolic apparatuses. The main electron coordinator in their chloroplasts, nicotinamide adenine dinucleotide phosphate (NADPH), participates in many enzymatic activities and is also responsible for inter-organellar communication. Under anaerobic conditions, green algae also accumulate molecular hydrogen (H₂), a promising alternative for fossil fuels. However, to scale-up its accumulation, a firm understanding of its integration in the photosynthetic apparatus is still required. While it is generally accepted that NADPH metabolism correlates to H₂ accumulation, the mechanism of this collaboration is still vague and relies on indirect measurements. Here, we investigated this connection in Chlamydomonas reinhardtii using simultaneous measurements of both dissolved gases concentration, NADPH fluorescence and electrochromic shifts at 520–546 nm. Our results indicate that energy transfer between H₂ and NADPH is bi-directional and crucial for the maintenance of redox balance under light fluctuations. At light onset, NADPH consumption initially eventuates in H₂ evolution, which initiates the photosynthetic electron flow. Later on, as illumination continues the majority of NADPH is diverted to the Calvin–Benson–Bassham cycle. Dark onset triggers re-assimilation of H₂, which produces NADPH and so, enables initiation of dark fermentative metabolism.

Energy transfer between H₂ and NADPH is bi-directional and crucial for the maintenance of redox balance under light fluctuations.