Unterschiede im revier- und sexualverhalten endemisch-anatolischer zahnkarpfen (pisces,cyprinodontidae)

The endemic Anatolian cyprinodonts Aphanius chantrei, A. (Kosswigichtys) asquamatus, and A. anatoliae show definite interspecific differences in their territorial and sexual behaviour under laboratory conditions. Intraspecific differences were found in the nine populations of A. anatoliae investigated.A. chantrei and Kosswigichthys show almost the same territorial behaviour. In A. anatoliae territoriality is found in three populations; the remaining six populations show no territoriality.The sexual behaviour consists of visual display elements and of elements which enable the fish to keep close contact without actually touching each other. The sequence of elements can be variable. Only two populations of A. anatoliae have retained display elements; the remaining seven populations have lost all of them.A correlation is discussed between biotope conditions and sexual behaviour. Display and territorial behaviour may have become superfluous in extreme, sulphate-containing habitats, where a lack of flora has led to a lack of spawning sites. Under changing breeding conditions the newly evolved element with fish staying close together (male underneath the female) may have replaced the former display elements.     

Two-dimensional gel analysis of swine histocompatibility antigens

Miniature swine MHC antigens from three inbred herds were examined by two-dimensional gel electrophoresis. These antigens were found to constitute a series of complex glycoproteins displaying haplotype-specific patterns that allowed the distinction of both class I and class II molecules among the three haplotypes. Selected outbred pig antisera reacted with a subset of class I antigens, suggesting the presence of at least two distinct molecular species among these antigens. Similarly, alloantisera reacting with mouse Ia antigens and a monoclonal anti-human DR were shown to immunoprecipitate a subset of class II molecules. Examination of the cells from two recombinant haplotypes demonstrated that both independent recombinational events took place between the class I and class II genes.     

Ein einfaches Mikrokolorimeter

Ohne Zusammenfassung     

Relationships among the streptothricin resistance transposons Tn1825 and Tn1826 and the trimethoprim resistance transposon Tn7

The streptothricin resistance transposons Tn1825 and Tn1826 are closely related, based on physical and genetic characteristics, to the trimethoprim resistance transposon Tn7. These transposons may be considered to be members of a transposon family sharing in common the transposition functions and a basic streptomycin/spectinomycin resistance determinant but differing from one another with respect to particular additional resistance genes inserted to the left of the aadA gene.     

Calculation of leaf photosynthetic parameters from light-response curves for ecophysiological applications

Measurement of the light response of photosynthetic CO₂ uptake is often used as an implement in ecophysiological studies. A method is described to calculate photosynthetic parameters, such as the maximum rate of whole electron transport and dissimilative respiration in the light, from the light response of CO₂ uptake. Examples of the light-response curves of flag leaves and ears of wheat (Triticum aestivum cv. ARKAS) are shown.Abbreviations and symbols A net photosynthesis rate - D ¹ rate of dissimilative respiration occurring in the light - f loss factor - I incident PPFD - I effective absorbed PPFD - J rate of whole electron transport - J _m maximum rate of whole electron transport - p ^c intercellular CO₂ partial pressure - PPFD photosynthetic photon flux density - q effectivity factor for the use of light (electrons/quanta) - absorption coefficient - I ^* CO₂ compensation point in the absence of dissimilative respiration (bar) - II conversion factor for calculation of CO₂ uptake from the rate of whole electron transport - convexity factor Gas-exchange rates relate to the projective area and are given in mol·m^-2·s^-1. Electron-transport rates are given in mol electrons·m^-2·s^-1; PPFD is given in mol quanta·m^-2·s^-1.     

Inhibition of gastric H+,K+-ATPase and acid secretion by SCH 28080, a substituted pyridyl(1,2a)imidazole

A hydrophobic amine, SCH 28080, 2-methyl-8-(phenylmethoxy)imidazo(1,2a)pyridine-3-acetonitrile, previously shown to inhibit gastric acid secretion in vivo and in vitro, was also shown to inhibit basal and stimulated aminopyrine accumulation in isolated gastric glands when histamine, high K+ concentrations, or dibutyryl cAMP were used as secretagogues. Stimulated, but not basal, oxygen consumption was also inhibited. Neutralization of the acid space of the parietal cell by high concentrations of the weak base, imidazole, reduced the potency of the drug, suggesting that SCH 28080 was active when protonated. Studies on the isolated H+,K+-ATPase showed that the compound inhibited the enzyme competitively with K+, whether ATP or p-nitrophenyl phosphate were used as substrates. In contrast, the inhibition was mixed with respect to p-nitrophenyl phosphate and uncompetitive with respect to ATP. The drug reduced the steady state level of the phosphoenzyme but not the observed rate constant for phosphoenzyme formation in the absence of K+ nor the quantity of phosphoenzyme reacting with K+. The drug quenched the fluorescence of fluorescein isothiocyanate-modified enzyme and also inhibited the ATP-independent K+ exchange reaction of the H+,K+-ATPase. Its action on gastric acid secretion can be explained by inhibition of the H+,K+-ATPase by reversible complexation of the enzyme. This class of compound, therefore, acts as a reversible inhibitor of gastric acid secretion.     

Antibody-dependent cellular cytotoxicity mediated by murine lymphocytes activated in recombinant interleukin 2

The incubation of murine splenocytes in recombinant interleukin 2 (RIL 2) gives rise to lymphokine-activated killer (LAK) cells that can lyse fresh, NK-resistant tumor cells but not normal cells in 4-hr 51Cr-release assays. Lysis by this IL 2-activated cell population was enhanced up to 100-fold by prior reaction of target cells with specific antisera reactive with antigens on the target cells. This antibody-dependent cellular cytotoxicity (ADCC) also resulted in lysis of fresh normal target cells, which are not usually susceptible to LAK lysis. The ADCC was evident after 24 hr of incubation of splenocytes in RIL 2, but peak lytic activity was reached after 3 to 4 days of incubation. The concentrations of RIL 2 needed for the in vitro activation of the effectors in order to attain maximal ADCC was between 100 and 3000 U/ml and parallel the IL 2 concentrations required to generate LAK cells. ADCC mediated by IL 2-activated splenocytes was completely blocked by anti-FcR monoclonal antibodies. Although antisera directed against MHC antigens were used in most experiments, anti-B16 monoclonal antibodies have also shown the ability to induce ADCC mediated by RIL 2-activated syngeneic and allogeneic cells. Treatment of the precursor splenocyte populations with anti-asialo GM1 and complement eliminated the direct LAK activity and the antibody-dependent cytotoxicity, suggesting that both direct and indirect tumor cell lysis may be caused by the same effector cell. ADCC mediated by LAK cell populations represents another possible mechanism for the in vivo therapeutic effects of these cells.