Island biology and morphological divergence of the Skyros wall lizard <Emphasis Type="Italic">Podarcis gaigeae</Emphasis>: a combined role for local selection and genetic drift on color morph frequency divergence?

Background  

Patterns of spatial variation in discrete phenotypic traits can be used to draw inferences about the adaptive significance of traits and evolutionary processes, especially when compared to patterns of neutral genetic variation. Population divergence in adaptive traits such as color morphs can be influenced by both local ecology and stochastic factors such as genetic drift or founder events. Here, we use quantitative color measurements of males and females of Skyros wall lizard, Podarcis gaigeae, to demonstrate that this species is polymorphic with respect to throat color, and the morphs form discrete phenotypic clusters with limited overlap between categories. We use divergence in throat color morph frequencies and compare that to neutral genetic variation to infer the evolutionary processes acting on islet- and mainland populations.     

Thermally-dried free and immobilized kefir cells as starter culture in hard-type cheese production

In an attempt to seek for suitable dried cultures, thermally-dried kefir was employed as starter in hard-type cheese production and tested in cheeses ripened at 5, 18 and 22 °C. Both free and immobilised on casein kefir cells were used and compared to cheese made without starter culture. Cheese products made with free cells of kefir culture were characterized by longer preservation time, improved aroma, taste, texture characteristics and increased degree of openness. Volatile profiles obtained by GC/MS analysis revealed a 216% increase in total concentration of esters, organic acids, alcohols and carbonyl compounds between cheeses prepared with and without kefir culture.     

Immunoreactivity of normal rabbit serum with epinephrine (E) cells of the rat adrenal medulla after microwave antigen retrieval

Normal rabbit serum (NRS) produces intense staining of epinephrine (E) cells in microwave-heated sections of rat and mouse adrenal gland. This staining is not eliminated by liver adsorption, complement inactivation, high salt buffer, Triton X-100 or dilution in normal goat serum and bovine serum albumin (BSA), suggesting that it may result from specific antigen-antibody interactions. Western blots of adrenal medullary protein probed with NRS reveal several bands. The major band does not correspond to rat chromogranin A, which is a major constituent of E-cell secretory granules. The findings suggest that NRS may contain autoantibodies against a secreted rabbit E-cell protein with a homologous counterpart in rats and mice, and that this protein may be immunologically unmasked in situ by microwave heating. This phenomenon is a potential source of error in immunohistochemical studies of the adrenal medulla, and has potential biological significance in neuroimmunology.     

Genetic diversity and population structure of the serpentine endemic Ni hyperaccumulator Alyssum lesbiacum

Alyssum lesbiacum is a well-established Ni hyperaccumulator, endemic to serpentine soils of Lesbos Island (Greece). A total of 95 individuals were collected from 17 plots encompassing the only four large populations of this species. ISSR (Inter-simple sequence repeat) markers were used to assess genetic diversity and population structure of A. lesbiacum to provide initial guidance for the development of successful management and conservation measures. A total of ten primers produced 82 bands, 96.34 % being polymorphic. The largest part of total diversity was found within populations, rather than among them. AMOVA analysis partitioned the largest part of diversity within plots (66 %), while 15 % contained among plots within populations and 19 % among populations. Principal coordinates analysis along with dendrogram based on genetic distances among populations showed a high degree of genetic differentiation of the isolated population Loutra. At a smaller scale, distance was not the most significant factor influencing the patterns of genetic diversity, but topography, ecosystem types and connectivity through streams. According to our results, conservation efforts should be organized at the level of watersheds and ecosystem types, considering them as management units. For ex situ conservation and restoration, seed samplings should be representative of the different habitats and watersheds as well as the patches of large and small populations while keeping the east population of Loutra separate from the other three central populations, to avoid any loss of genetic diversity and to preserve the character of the local adapted populations.     

The squalestatins: novel inhibitors of squalene synthase. The optimal C1 chain-length requirements.

Analogues of squalestatin 1 modified in th C1 side-chain were prepared and evaluated for their ability to inhibit squalene synthase in vitro. An appropriately substituted 6-phenylhexyl chain was found to be optimal for effective enzyme inhibition.     

The PPGMRPP repetitive epitope of the Sm autoantigen: Antigenic specificity induced by conformational changes. Application of the Sequential Oligopeptide Carriers (SOCs)

Summary The PPGMRPP sequence, found in several copies in the Sm and U1RNP autoantigens, is the main target of anti-Sm and anti-U1RNP antibodies in systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) patient's sera. It is also recognized, to a lower extent, by anti-Ro/SSA and anti-La/SSB specificities. The PPGMRPP-NH₂ peptide amide and the PPGMRPP peptide, which is bound to a pentameric sequential oligopeptide carrier (SOC₅), were examined by¹H-NMR spectroscopy and ELISA assays, using sera from patients with autimmune rheumatic diseases. Among the three main conformers found for the free PPGMRPP, the extended one was also identified for PPGMRPP-NH₂ and (PPGMRPP)₅-SOC₅. This can be attributed to the absence of ionic interactions between the Arg-guanidinium and the carboxylate group in the amide and SOC₅-bound forms of the peptide. Immunoassays using sera from various specificities showed an enhanced anti-Sm and anti-U1RNP recognition of PPGMRPP-NH₂ and (PPGMRPP)₅-SOC₅, and lowering of the anti-Ro/SSA and anti-La/SSB reactivity. The presence of multiple conformers of free PPGMRPP may explain the unexpected cross-reactivity to the anti-Ro/La positive sera, while the prevalence of the extended conformation in PPGMRPP-NH₂ and (PPGMRPP)₅-SOC₅ is mainly responsible for the enhanced recognition from the anti-Sm and anti-U1RNP autoantibodies. it is concluded that the antigenic specificity of PPGMRPP-NH₂ and (PPGMRPP)₅-SOC₅ is mainly induced by conformational changes resulting from the conversion of the C-terminal carboxylate group to the amide form.     

Preservation of Turkey spermatozoa by the use of emulsions and supercooling methods

Techniques are described for the emulsification and supercooling of turkey spermatozoa. Selection of an appropriate emulsification medium was carried out after tests for spermicidal properties and droplet stability were performed. Differential thermal analysis (DTA) studies were employed to measure the temperatures of spontaneous nucleation of the suspended semen droplets during cooling.During the fertility trial it was shown that the entrapment of spermatozoa in Dow 230 carrying fluid reduced the fertility (P < 0.05) from 91.6 to 81.2%. Additional significant reductions were observed for 1 hr at ?21 °C (64.9%) and during the separation of the carrying fluid and semen via centrifugation (57.2%). This indicates that the separation of the Dow 230 from the semen is not necessary and the semen can be artificially inseminated in its emulsified form.The decline in fertility of the emulsified semen stored at ?21 °C for 1 hr could be attributed to possible damage during freezing of some suspended semen droplets as seen in thermograms of emulsified semen. Additional work in this area should be directed toward elucidating the controlling factors of supercooling as they relate to possible in vitro cryopreservation.