Phylogeny and spatio-temporal distribution of European Pectinidae (Mollusca: Bivalvia)

Phylogenetic relationships within Pectinidae (Bivalvia, Pteriomorphia) have been investigated primarily for Pacific and Western Atlantic or commercially valuable taxa. Most molecular phylogenetic studies have revealed monophyly of pectinid bivalves but interrelationships of the different clades are still inconsistent. However, non-commercial European Pectinidae has mostly been neglected in earlier investigations and therefore the evolution and radiation of the European Pectinidae is poorly understood. Since the fossil record of this group is well investigated, the evolutionary age of phylogenetic diversification and radiation events within this group can be dated. Thus, the connection of geological and climatic changes to radiation events within this group can be assessed. We investigated the phylogenetic relationships within European Pectinidae using mitochondrial (12S and 16S) and nuclear (18S, 28S and H3) gene markers and performed relaxed molecular clock approaches to gain information on the evolutionary age and the connection between Cenozoic climatic changes and diversification within this group. The results show concordance of radiation events with the Middle Miocene cooling event and the following climatic period with slowly decreasing temperatures. However, geological changes such as the uplift of the Gomphotherium Landbridge or the closure and re-opening of the Strait of Gibraltar also had great impact on diversification and distribution patterns within European Pectinidae.     

The water-sweet aftertaste of neohesperidin dihydrochalcone and thaumatin as a method for determining their sweet persistence

The water–sweet aftertaste produced in humans in responseto tasting intensive sweeteners such as neohesperidin dihydrochalconeand thaumatin was studied. This water–sweet aftertasteincreased with sweetener concentration and diminished with time.The decay in the sweet intensity–time relationships fitteda negative exponential function in a pattern similar to thatwhich occurs when other methods for determining persistenceare employed. Persistence time contants (T) were dependent uponthe maximal perceived sweet intensity (Ip-max) observed at theinitial time of tasting. The use of this procedure is proposedfor determining persistence of intensive sweeteners under circumstanceswhere controlled pH and temperature are desired.     

Constitutive Production of Macrophage Colony-Stimulating Factor and Interleukin-6 by Human Ovarian Surface Epithelial Cells

Normal and neoplastic epithelial cells produce growth factors that can affect cells from different lineages. Epithelial ovarian cancers produce M-CSF and IL-6. In the present study, production of these cytokines has been measured in the apparently normal epithelial cells from which epithelial ovarian neoplasms are thought to arise. Epithelial cells from the surface of premenopausal human ovaries were established in short-term cultures. The cells bound anti-cytokeratin antibodies and exhibited characteristic epithelial morphology by light and transmission electron microscopy. M-CSF and IL-6 were detected in supernatants from cultures of these cells, using assays specific for each factor. Cytokine levels were comparable to those in supernatants from ovarian and breast cancer cell lines. M-CSF expression could also be demonstrated by immunohistochemical analysis with specific rabbit heteroantiserum. Thus, M-CSF and IL-6 are produced constitutively by normal as well as by neoplastic ovarian epithelium.     

Effects of the bitter additives naringin and sucrose octa-acetate on sweet persistence and sweet quality of neohesperidin dihydrochalcone

The maximal perceived sweet intensity (Ip_max) and the sweetpersistence constant (T) of neohesperidin dihydrochalcone (NHD),were significantly reduced in a mixture containing naringin(NAR), a bitter flavone analog of NHD Sucrose octa-acetate (SOA),another bitter stimulus, reduced the Ip_max of NHD in mixtures,but no appreciable decrease in T values was found. Linear regressionanalyses performed on the IP_max data of either NHD + NAR orNHD + SOA (logIp_max versus log concentration) produced slopevalues lower than those of NHD alone. Moreover, taste similarityexperiments revealed that the mixture of NHD + NAR was locatedfurther than NHD from the sugar area in the multi-dimensionalscaling (MDS) map. It is concluded that the reduction in Tvaluesof NHD by NAR was apparently related to the reduced Ip_max levelsand that such a mixture produces a sweet quality inferior tothat of NHD.     

Spectral EMG changes in vastus medialis muscle following short range of motion isokinetic training.

This study was aimed at exploring the carryover effect of short range of motion (RoM) isokinetic conditioning on vastus medialis (VM) motor unit recruitment (MUR) across the full RoM. Fifty-five women were randomly assigned to one of four groups: G1 (n = 14) and G2 (n = 14) trained concentrically at 30 and 90 degrees /s, respectively whereas G3 (n = 13) and G4 (n = 14) trained similarly but using the eccentric mode. All 4 groups trained within 30-60 degrees of knee flexion. The training protocol consisted of 4 sets of 10 maximal repetitions, 3 times a week for 6 weeks. sEMG was recorded from the VM for analysis of mean frequency of the EMG power spectrum prior to the training period and 2 days after its termination. The EMG assessments took place during dynamic contractions within 3 angular RoM's: 85-60 degrees (R1), 60-30 degrees (R2) and 30-5 degrees (R3). In addition MUR was evaluated during isometric contractions at 10 degrees , 45 degrees and 80 degrees . Significant increases were observed in the MUR at R1, R2, and R3 during dynamic contractions as well as in all 3 angles during isometric contractions. These findings applied equally regardless of the mode of contraction and motion speed during training. The fact that MUR increased significantly within untrained RoM's may point out to the potential benefits of short RoM conditioning, particularly in those cases where, during specific phases of rehabilitation, a wider RoM may be contraindicative.     

Intramolecularly quenched fluorogenic substrates for hydrolytic enzymes.

The design and application of a recently developed type of fluorogenic substrates for proteolytic enzymes is reviewed. The substrates consist of peptide chains constructed to match the specificity of the particular enzyme and to bear a suitable chromophore at each side of the cleavable bond. One of the chromophores is a fluorescent group and the other is a quencher that causes a great reduction of fluorescence intensity of the fluorophore, either by direct intramolecular encounter or by radiationless resonance energy transfer. Enzymic cleavage of the molecule is followed by release of fluorescence as the result of cancelling the quenching interaction between the chromophores. The properties of such substrates and their possible future applications are discussed.