Long-term cold acclimation leads to high Q10 effects on oxygen consumption of loggerhead sea turtles Caretta caretta

We monitored oxygen consumption (VO2), body temperatures (Tb), submersion intervals, and circadian rhythms of VO2 in nine loggerhead turtles during a 6-mo period. The turtles originated from the Tyrhennian Sea, South Italy (40 degrees 51'N, 14 degrees 17'E) and were kept in indoor tanks at constant photoperiod while being subject to the seasonal decline in water temperature (Tw=27.1 degrees to 15.3 degrees C). From summer to winter, all turtles underwent profound reductions in VO2 (Q10=5.4). Simultaneously, their activity was greatly reduced and submergence intervals increased. Over 24-h periods, however, the turtles showed no circadian rhythm in activity or VO2. However, there was a significant positive correlation between the proportion of a day spent actively swimming and VO2. Tb's were not significantly different from Tw and followed the same seasonal decline. A second experiment was conducted to establish the effect of short-term exposure to various temperatures on VO2. Tb equilibrated with the experimental Tw within 3 h. The metabolic responses were again positively correlated with changes in Tw, but this time the corresponding Q10 was only 1.3. On the basis of the range of body masses of the turtles used in this study (2-60 kg), the intraspecific scaling exponent for VO2 was 0.353.     

HitKeeper, a generic software package for hit list management

Background  

The automated annotation of biological sequences (protein, DNA) relies on the computation of hits (predicted features) on the sequences using various algorithms. Public databases of biological sequences provide a wealth of biological "knowledge", for example manually validated annotations (features) that are located on the sequences, but mining the sequence annotations and especially the predicted and curated features requires dedicated tools. Due to the heterogeneity and diversity of the biological information, it is difficult to handle redundancy, frequent updates, taxonomic information and "private" data together with computational algorithms in a common workflow.     

Dual task-related changes in the synchronous activity of wrist extensor type-identified motor units in humans

The coupling between the firings of 33 pairs of motor units tested in the extensor carpi radialis muscles was evaluated by cross-correlation analysis and compared during isometric wrist extension and hand clenching. A slightly greater amount of synchrony was observed during hand clenching (0.042 &#45 0.024 vs 0.035 &#45 0.017 synchronous impulses per trigger). This trend did not reach however the level of significance and the changes were actually found to be heterogeneous: in 15 out of the 33 pairs tested, synchronous activity with a narrow coupling (4.6 &#45 2.4 ms) consistent with short-term synchrony was greater during hand clenching whereas in nine other pairs, synchronous activity with a broader dispersion (9.0 &#45 4.5 ms) was reduced. These opposite changes could not be explained in terms of changes in the firing pattern of the motor units and were found instead to correlate with the motor units' biomechanical properties. Motor units with high recruitment thresholds and fast rising twitches showed predominantly an increase in synchrony; whereas the motor unit pairs with low recruitment thresholds and slow twitches showed either an increase or a decrease. The enhanced short-term synchrony suggests that common inputs distributed to motoneurones of all types were more effective during hand clenching whereas the decrease in weakly coupled synchronous activity suggests that other inputs synchronized at a pre-synaptic level and distributed more specifically to motor units recruited at low force levels were less effective. The possible origins of the inputs reflected in the dual changes are discussed in terms of the supra-spinal and peripheral pathways controlling the wrist extensor motoneurones during wrist extension and hand clenching.     

A Photochemical Mechanism for Homochirogenesis. Part 2

A theoretical investigation of the photochemistry of racemic compounds with circularly polarized light was undertaken. The exact solutions of the differential equations by numerical integration to the approximate solutions used in an earlier article were compared. The exact solutions showed that sequential reactions yield enhanced optical activities in the products. For irreversible reactions, all enantiomeric excesses are lost if the reactions are carried to completion, but appreciable resolution occurs in many cases for partial conversion. For reversible reactions, significant enantiomeric excesses are found at the photostationary state. Chirality 25:16‐21, 2013. © 2012 Wiley Periodicals, Inc.     

Biological and phytochemical aspects of Valeriana officinalis

Two populations of Valeriana officinalis L. subsp. collina (Wallr.) Nyman show considerable differences in anatomy and chemistry and one of them contains an accessory B chromosome, which is not present in the other. In consideration of the metabolic and adaptive role of this type of chromosome the hypothesis is put forward that there is a connection between the presence of an accessory chromosome and the histological, anatomical and chemical physiognomy of a particular population. This connection would involve considerable practical implications in the field of pharmaceutics.     

Inclusion bodies in loggerhead erythrocytes are associated with unstable hemoglobin and resemble human Heinz bodies

The aim of this study was to clarify the role of the erythrocyte inclusions found during the hematological screening of loggerhead population of the Mediterranean Sea. We studied the erythrocyte inclusions in blood specimens collected from six juvenile and nine adult specimens of the loggerhead turtle, Caretta caretta, from the Adriatic and Tyrrhenian Seas. Our study indicates that the percentage of mature erythrocytes containing inclusions ranged from 3 to 82%. Each erythrocyte contained only one round inclusion body. Inclusion bodies stained with May Grünwald-Giemsa show that their cytochemical and ultrastructure characteristics are identical to those of human Heinz bodies. Because Heinz bodies originate from the precipitation of unstable hemoglobin (Hb) and cause globular osmotic resistance to increase, we analyzed loggerhead Hb using electrophoresis and high-performance liquid chromatography to detect and quantitate Hb fractions. We also tested the resistance of Hb to alkaline pH, heat, isopropanol denaturation, and globular osmosis. Our hemogram results excluded the occurrence of any infection, which could be associated with an inclusion body, in all the specimens. Negative Feulgen staining indicated that the inclusion bodies are not derived from DNA fragmentation. We hypothesize that amino acid substitutions could explain why loggerhead Hb precipitates under normal physiologic conditions, forming Heinz bodies. The identification of inclusion bodies in loggerhead erythrocytes allow us to better understand the haematological characteristics and the physiology of these ancient reptiles, thus aiding efforts to conserve such an endangered species.     

Pluripotent plasticity of stem cells and liver repopulation

Different types of stem cells have a role in liver regeneration or fibrous repair during and after several liver diseases. Otherwise, the origin of hepatic and/or extra‐hepatic stem cells in reactive liver repopulation is under controversy. The ability of the human body to self‐repair and replace the cells and tissues of some organs is often evident. It has been estimated that complete renewal of liver tissue takes place in about a year. Replacement of lost liver tissues is accomplished by proliferation of mature hepatocytes, hepatic oval stem cells differentiation, and sinusoidal cells as support. Hepatic oval cells display a distinct phenotype and have been shown to be a bipotential progenitor of two types of epithelial cells found in the liver, hepatocytes, and bile ductular cells. In gastroenterology and hepatology, the first attempts to translate stem cell basic research into novel therapeutic strategies have been made for the treatment of several disorders, such as inflammatory bowel diseases, diabetes mellitus, celiachy, and acute or chronic hepatopaties. In the future, pluripotent plasticity of stem cells will open a variety of clinical application strategies for the treatment of tissue injuries, degenerated organs. The promise of liver stem cells lie in their potential to provide a continuous and readily available source of liver cells that can be used for gene therapy, cell transplant, bio‐artificial liver‐assisted devices, drug toxicology testing, and use as an in vitro model to understand the developmental biology of the liver. Copyright © 2010 John Wiley & Sons, Ltd.