Development of ovaries in bovine fetuses

The growth of ovaries, development of germ cells, formation of sex cords, folliculogenesis and dependence of these processes on the gonad morphogenesis stages were studied on 68 embryos and foetuses at the age of 1.5 to 9 months. Sex differentiation of ovaries was shown to take place in 1.5 month old embryo. The cords of connective tissue's cortical stroma appear also in 1.5 month old embryo, they develop in the dorsoventral direction and reach the gonad's covering epithelium in 6 month old foetuses. The formation of the medulla rudiment starts in 1.5 month old embryo when the gonad is separated from mesonephros and connected with it via the ovary gate. In 4 month old foetuses the ovary net transforms into a stellate structure. Important morphogenetic processes, such as the development of the ovary somatic elements, entry of the oocytes into meiotic prophase, formation of the sex cords and folliculogenesis, develop in the dorsoventral direction Germ cells in 9 month old foetuses are enclosed into primordial or, growing follicles.     

Amyloidogenic properties of the artificial protein albebetin and its biologically active derivatives. The role of electrostatic interactions in fibril formation

The artificial protein albebetin (ABB) and its derivatives containing biologically active fragments of natural proteins form fibrils at physiological pH. The amyloid nature of the fibrils was confirmed by far UV circular dichroism spectra indicating for rich beta-structure, thioflavin T binding assays, and examination of the obtained polymers by atomic force microscopy. Fusing of short peptides--octapeptide of human alpha(2)-interferon (130-137) or hexapeptide HLDF-6 (41-46) of human leukemia differentiation factor--with the N-terminus of ABB led to increased amyloidogenicity of the protein: the rate of fibril formation increased and the morphology of fibrils became more complex. The presence of free hexapeptide HLDF-6 in the ABB solution had the same effect. Increasing ionic strength also activated the process of amyloid formation, but to less extent than did the peptides fused with ABB or added to the ABB solution. We suggest an important role of electrostatic interactions in formation of ABB fibrils. The foregoing ways (addition of salt or peptides) allow decrease in electrostatic repulsion between ABB molecules carrying large negative charge (-12) at neutral pH, thus promoting fibril formation.     

Association of the <Emphasis Type="Italic">PTPN22</Emphasis> polymorphism <Emphasis Type="Italic">C1858T</Emphasis> with type 1 diabetes mellitus

PTPN22 encodes a lymphoid protein tyrosine phosphatase LYP. Association of the PTPN22 polymorphism C1858T with type 1 diabetes mellitus was investigated using the transmission disequilibrium test (TDT) and a comparative analysis of the allele and genotype frequency distributions. The study involved two groups of families from Russian populations of Moscow and Samara with concordantly (27 families) and discordantly (62 families) affected sibs, as well as groups of type 1 diabetes patients and healthy individuals. The association of the PTPN22 polymorphism with type 1 diabetes was not significant by TDT analysis, but was significant by comparison of the allele and genotype frequency distributions. Thus, a case-control analysis detected an association of the PTPN22 polymorphism C1858T with type 1 diabetes mellitus in Russians.     

Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name ‘soldier flies’, occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 °C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.     

The effects of melatonin and L-DOPA on the diurnal rhythms of free amino acids content in the rat retina

The effects of melatonin and dopamine precursor L-3,4-dihydroxyphenylalanine (L-DOPA) intraperitoneal administration on the rhythms of free amino acids content in the retina of rats were studied. The authors found that the levels of those amino acids, which are protein constituents but not neurotransmitters in the rat retina, change diurnally with maximum at 3-6 h after light onset. Diurnal changes of Ala, Arg, Asn, Ile, Met, Ser, Trp, and Val content persisted in the retina of rats maintained at constant darkness. This fact confirms the true circadian nature of these rhythms. Constant lighting abolished diurnal changes of the content of all amino acids with the exception of Trp. Daytime but not nighttime administration of melatonin decreased the levels of Ala, Asn, Gln, Ile, Met, and Ser down to nocturnal values. Diurnal changes of amino acids content vanished in melatonin-injected rats. The effect of melatonin administration disappeared when the protein synthesis was inhibited by cycloheximide. The effect of intraperitoneal administration of L-DOPA on the levels of free amino acids was opposite the effect of melatonin administration. L-DOPA increased nocturnal levels of Gly, Thr, Trp, and Val but had no effect on the daytime amino acids content. As in the case of melatonin administration, significant diurnal changes of amino acid levels disappeared in L-DOPA-injected rats. The authors hypothesize that melatonin and dopamine can serve as zeitgebers-antagonists of amino acids content rhythms in the rat retina.     

Molecular phylogeny of fungus gnats (Diptera: Mycetophilidae) revisited: position of Manotinae,Metanepsiini, and other enigmatic taxa as inferred from multigene analysis

The phylogeny of selected genera from four subfamilies of fungus gnats (Diptera: Mycetophilidae) – Manotinae, Leiinae, Sciophilinae and Gnoristinae (including Metanepsiini) – is reconstructed based on the combined analysis of five mitochondrial (12S, 16S, COI, COII, cytB) and two nuclear (28S, ITS2) gene markers. Results of the different analyses all support Manotinae as a monophyletic group, with Leiinae as the sister group. Allactoneura DeMeijere is nested in the monophyletic and strongly supported clade of Leiinae. The tribe Metanepsiini is revealed as paraphyletic and the genera Metanepsia Edwards and Chalastonepsia Søli do not appear to be closely related. The genera Docosia Winnertz, Ectrepesthoneura Enderlein, Novakia Strobl and Syntemna Winnertz were placed with a group of genera included traditionally in the Gnoristinae. The monophyly of Dziedzickia Johannsen and Phthinia Winnertz is not supported. The genera of Sciophilinae (excluding Paratinia Mik but including Eudicrana Loew) form a monophyletic group in the Bayesian model.     

A genomic walking method for screening sequence length polymorphism

We adapted a recently developed nonrestrictional, nonligational genome walking method, Universal Fast Walking (UFW), for detection of length polymorphism in the proximal promoter region of genes. We demonstrate its efficacy at discovering naturally occurring transposition into heat‐shock genes of wild Drosophila and show that it surmounts limitations of simple polymerase chain reaction (PCR) approaches. We further present modifications to the standard UFW protocol and provide some guidelines to improve specificity. Although the resultant banding pattern of a standard UFW can be regarded as a DNA fingerprint, many amplicons result from false priming and not real polymorphisms. We describe ways to distinguish between UFW amplicons and false priming products in a high‐throughput assay.