Emergence and dispersal relative to natal nest in the digger wasp Stizus continuus (Hymenoptera: Crabronidae)

The position of the emerging point has rarely been investigated as a factor possibly affecting the future nest settlement behaviour in Hymenoptera, in particular within nest aggregations. We studied the emergence and dispersion patterns of the digger wasp Stizus continuus. Individuals emerged daily in clumped patterns, possibly revealing a certain synchrony of emergence from the same nests, and protandry appeared both at seasonal and daily level. Differences between the number of females that nested relatively close or far from their emergence holes (EH) were either significant or not, depending on the year, and observed dispersal distances from the natal nests did not differ from those obtained by random simulations. By contrast, females nested close to the nearest conspecific nest. Size did not affect the dispersion patterns. EH are thus not important cues for nest establishment, and conspecific nests are probably the key cue for nest-founding females. In addition, males did not prefer to establish territories close to their natal nest.     

Chemical variability of the wood essential oil of Cedrus atlantica Manetti from Corsica

The composition of 48 samples of essential oil isolated from the wood of Cedrus atlantica growing in Corsica was investigated by GC (in combination with retention indices), GC/MS, and (13) C-NMR. Twenty-three compounds accounting for 73.9-96.0% of the oil composition were identified. The oils consisted mainly of monoterpene hydrocarbons and sesquiterpenes, in particular α-pinene (5; up to 79.4%), himachalol (4; up to 66.2%), β-pinene (up to 21.4%), β-himachalene (2; up to 19.3%), γ-himachalene (3; up to 11.0%), and α-himachalene (1; up to 10.9%). The 48 oil compositions were submitted to k-means partitioning and principal-component analysis, which allowed the distinction of two groups within the oil samples. The composition of Group I (44% of the samples) was dominated by 5, while the samples of Group II (56% of the samples) contained mainly 4.     

Chemical Variability of the Leaf Essential Oil of Xylopia aethiopica (Dunal) A.Rich. from Côte d'Ivoire

The chemical composition of 48 essential‐oil samples isolated from the leaves of Xylopia aethiopica harvested in six Ivoirian forests was investigated by GC‐FID and ¹³C‐NMR analyses. In total, 23 components accounting for 82.5–96.1% of the oil composition were identified. The composition was dominated by the monoterpene hydrocarbons β‐pinene (up to 61.1%) and α‐pinene (up to 18.6%) and the sesquiterpene hydrocarbon germacrene D (up to 28.7%). Hierarchical cluster and principal component analyses allowed the distinction of two groups on the basis of the β‐pinene and germacrene D contents. The chemical composition of the oils of Group I (38 oil samples) was clearly dominated by β‐pinene, while those of Group II (10 samples) were characterized by the association of β‐pinene and germacrene D. The leaves collected in the four inland forests produced β‐pinene‐rich oils (Group I), while the oil samples belonging to Group II were isolated from leaves harvested in forests located near the littoral.     

Characteristics Associated With Fasting Appetite Hormones (Obestatin,Ghrelin, and Leptin)

Obestatin, derived from the same gene as the hunger hormone ghrelin, may reduce food intake in animals. The role of obestatin in human physiology is unclear. We evaluated cross‐sectional associations between participant characteristics and fasting levels of obestatin as well two other hormones associated with energy balance, ghrelin and leptin. Data are from the baseline visit of the Optimal Macronutrient Intake Trial to Prevent Heart Disease (OMNI‐Heart) Trial that enrolled adults with elevated blood pressure (systolic 120–159 mm Hg or a diastolic of 80–99 mm Hg) but who were otherwise healthy. Partial Spearman's correlations and linear regression models estimated the association between age, gender, BMI, physical activity, and smoking with fasting hormones. Obestatin was directly associated with ghrelin (r = 0.45, P < 0.05). On average, overweight (BMI 25–30) and obese (BMI > 30) individuals had obestatin concentrations that were 12.6 (s.d. 8.8) and 25.4 (s.d. 8.4) pg/ml lower compared to normal weight (BMI < 25) individuals, respectively (P for trend = 0.002). Overweight (BMI 25–30) and obese (BMI > 30) individuals had ghrelin concentrations that were 161.7 (s.d. 69.6) and 284.7 (s.d. 66.5) pg/ml lower compared to normal weight (BMI < 25) individuals, respectively (P for trend <0.0001). A 5 unit increase in BMI was associated with 41.3% (s.d. 4.3%) (P < 0.0001) higher leptin. Obestatin and ghrelin are directly correlated and share the same patterns of association with participant characteristics. Modifiable risk factors for chronic diseases, such as BMI, are associated with fasting levels of leptin, obestatin, and ghrelin.     

Hedgehog can drive terminal differentiation of amniote slow skeletal muscle

Background

Secreted Hedgehog (Hh) signalling molecules have profound influences on many developing and regenerating tissues. Yet in most vertebrate tissues it is unclear which Hh-responses are the direct result of Hh action on a particular cell type because Hhs frequently elicit secondary signals. In developing skeletal muscle, Hhs promote slow myogenesis in zebrafish and are involved in specification of medial muscle cells in amniote somites. However, the extent to which non-myogenic cells, myoblasts or differentiating myocytes are direct or indirect targets of Hh signalling is not known.

Results

We show that Sonic hedgehog (Shh) can act directly on cultured C2 myoblasts, driving Gli1 expression, myogenin up-regulation and terminal differentiation, even in the presence of growth factors that normally prevent differentiation. Distinct myoblasts respond differently to Shh: in some slow myosin expression is increased, whereas in others Shh simply enhances terminal differentiation. Exposure of chick wing bud cells to Shh in culture increases numbers of both muscle and non-muscle cells, yet simultaneously enhances differentiation of myoblasts. The small proportion of differentiated muscle cells expressing definitive slow myosin can be doubled by Shh. Shh over-expression in chick limb bud reduces muscle mass at early developmental stages while inducing ectopic slow muscle fibre formation. Abundant later-differentiating fibres, however, do not express extra slow myosin. Conversely, Hh loss of function in the limb bud, caused by implanting hybridoma cells expressing a functionally blocking anti-Hh antibody, reduces early slow muscle formation and differentiation, but does not prevent later slow myogenesis. Analysis of Hh knockout mice indicates that Shh promotes early somitic slow myogenesis.

Conclusions

Taken together, the data show that Hh can have direct pro-differentiative effects on myoblasts and that early-developing muscle requires Hh for normal differentiation and slow myosin expression. We propose a simple model of how direct and indirect effects of Hh regulate early limb myogenesis.

     

Enolase from the ectomycorrhizal fungus Tuber borchii Vittad.: biochemical characterization, molecular cloning, and localization

Enolase from Tuber borchii mycelium was purified to electrophoretical homogeneity using an anion-exchange and a gel permeation chromatography. Furthermore, the corresponding gene (eno-1) was cloned and characterized. The purified enzyme showed a higher affinity for 2-PGA (0.26 mM) with respect to PEP; the stability and activity of enolase were dependent of the divalent cation Mg2+. T. borchii eno-1 has an ORF of 1323 bp coding for a putative protein of 440 amino acids and Southern blotting analysis revealed that the gene is present as a single copy in T. borchii. The enzymatic activity and the mRNA expression level evaluated in mycelia grown either in different carbon sources, in pyruvate or during starvation were the same in all the conditions tested, while biochemical and Northern blotting analyses performed with mycelia at different days of growth showed T. borchii eno-1 regulation in response to the growth phase. Finally, Western blotting analysis demonstrated that enolase is localized only in the cytosolic fraction confirming its important role in glycolysis.     

Synoviocytes, not chondrocytes, release free radicals after cycles of anoxia/re-oxygenation

By oxymetry and electron paramagnetic resonance (EPR), we investigated the effects of repeated anoxia/re-oxygenation (A/R) periods on the respiration and production of free radicals by synoviocytes (rabbit HIG-82 cell line and primary equine synoviocytes) and equine articular chondrocytes. Three periods of 20 min anoxia followed by re-oxygenation were applied to 10(7)cells; O(2) consumption was measured before anoxia and after each re-oxygenation. After the last A/R, cellular free radical formation was investigated by EPR spectroscopy with spin trapping technique (n=3 for each cell line). Both types of synoviocytes showed a high O(2) consumption, which was slowered after anoxia. By EPR with the spin trap POBN, we proved a free radical formation. Results were similar for equine and rabbit synoviocytes. For chondrocytes, we observed a low O(2) consumption, unchanged by anoxia, and no free radical production. These observations suggest an oxidant activity of synoviocytes, potentially important for the onset of osteoarthritis.     

Expression and purification of a Tuber borchii fruitbody-specific protein, TBF-1, from Escherichia coli: generation of polyclonal antibodies

TBF-1 is a fruitbody-specific protein present in the white truffle species Tuber borchii Vittad. A similar protein has been found only in the closely related species Tuber dryophilum (TDF-1), but not in other truffles. The protein from T. borchii was overexpressed as fusion protein in E. coli and was purified to homogeneity by affinity chromatography. Recombinant protein was used for generating polyclonal antibodies. The antiserum strongly reacted with TBF-1, weakly recognized TDF-1, and did not detect correlate band in the other white truffle species. The high level of expression of this protein in the fruitbody and the specificity of the antibody anti-TBF-1 make it possible to set up a diagnostic tool for detecting these species in natural samples and foodstuffs.     

Quantification of lipid bilayer effective microviscosity and fluidity effect induced by propofol

Electron spin resonance (ESR) spectroscopy with nitroxide spin probes was used as a method to probe the liposome microenvironments. The effective microviscosities have been determined from the calibration of the ESR spectra of the probes in solvent mixtures of known viscosities. In the first time, by measuring ESR order parameter (S) and correlation time (tau(c)) of stearic spin probes, we have been able to quantify the value of effective microviscosity at different depths inside the liposome membrane. At room temperature, local microviscosities measured in dimyristoyl-l-alpha phosphatidylcholine (DMPC) liposome membrane at the different depths of 7.8, 16.95, and 27.7 A were 222.53, 64.09, and 62.56 cP, respectively. In the gel state (10 degrees C), those microviscosity values increased to 472.56, 370.61, and 243.37 cP. In a second time, we have applied this technique to determine the modifications in membrane microviscosity induced by 2,6-diisopropyl phenol (propofol; PPF), an anaesthetic agent extensively used in clinical practice. Propofol is characterized by a unique phenolic structure, absent in the other conventional anaesthetics. Indeed, given its lipophilic property, propofol is presumed to penetrate into and interact with membrane lipids and hence to induce changes in membrane fluidity. Incorporation of propofol into dimyristoyl-l-alpha phosphatidylcholine liposomes above the phase-transition temperature (23.9 degrees C) did not change microviscosity. At 10 degrees C, an increase of propofol concentration from 0 to 1.0 x 10(-2) M for a constant lipid concentration mainly induced a decrease in microviscosity. This fluidity effect of propofol has been qualitatively confirmed using merocyanine 540 (MC540) as lipid packing probe. Above 10(-2) M propofol, no further decrease in microviscosity was observed, and the microviscosity at the studied depths (7.8, 16.95, and 27.7 A) amounted 260.21, 123.87, and 102.27 cP, respectively. The concentration 10(-2) M was identified as the saturation limit of propofol in dimyristoyl-l-alpha phosphatidylcholine liposomes.