Effect of various amino acids and ammonium salts in a synthetic culture media on the cholera enterotoxin production

The influence of amino acids and ammonium salts on the production of cholera enterotoxin (CT) by 3 Vibrio cholerae strains of different biovars and serogroups was evaluated. As revealed in this study, toxin formation in each of the strains was quantitatively and qualitatively determined by their individual sets of amino acids. The amino acid compositions ensuring the maximum production of CT by the V. cholerae strains under study were formed. The use of ammonium salts as the only source of nitrogen in the composition of a synthetic nutrient medium for the accumulation of CT was shown to be inexpedient.     

A giant rhinocerotoid (Mammalia, Perissodactyla) from the Late Oligocene of north-central Anatolia (Turkey)

A giant rhinocerotoid is described for the first time south of the Black Sea, in Turkey. The single specimen, a fragmentary radius referred to Paraceratherium sp., originates from conglomerates nearby at Gözükizilli, in the Çankiri–Çorum Tertiary basin. These layers correspond to the Lower member of the Kizilirmak Formation. The same locality (Gözükizilli-2) yields also the small rhinocerotid Protaceratherium sp., cf. P. albigense (Roman, 1912). Three other mammal localities (Gözükizilli-1, in the Lower Member of the formation, with several rodent species; Tepe 641 and Kizilirmak, in the Upper Member, with a diversified micro- and macro-mammal fauna) allow us to refer the Kizilirmak Formation as a whole to the Late Oligocene. All the observed taxa have strong Asian and/or European affinities, which precludes any geographical insulation for this part of Anatolia during the Late Oligocene.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 152 , 581–592.     

Intracellular and extracellular labeling of neurons in fresh slice preparations combined with multiple tract tracing

We describe methods for studying axo-dendritic projections, one of the forms of neural connection involved in the complex circuits of the central nervous system, including brainstem auditory pathways. This form of neural connection is often difficult to visualize by conventional tract tracing techniques. Retrogradely identified cells were filled intracellularly with a mixture of fluorescent Lucifer yellow and nonfluorescent HRP in live slice preparations to reveal the detailed morphological features of these cells with special attention to the distal dendrite that may receive projections from suspected or known input axons. Extracellular or intracellular labeling of cells with axons that project to the distal dendrite of the identified cells was accomplished in the same live slice preparation. Using a live slice rather than a fixed slice allows accurate, visually controlled placement of anterograde tracer, which requires living axons for transport, into the source of input to the identified cells within the slice. Live slices also permit one to characterize the identified cells electrophysiologically. Intracellular labeling of cells in a potential source of local input to the identified cells also provides conclusive information concerning with connections of the cells involved.     

The epidemiological importance of Vibrio cholerae isolated from different ecological systems

The analysis of the data on the isolation of V. cholerae from different ecological systems indicates that V. eltor do not constantly inhibit the rivers and sea at the territory under control. Hemolytically active V. cholerae without the vct gene, found to be faintly virulent and avirulent when studied on suckling rabbits used as a model and when evaluated by the complex method, show no tendency towards epidemic spread in the presence of conditions for the realization of the transmission of vibrios by the water route.