[The significance of FeLV infection for diseases in necropsied cats]. / Untersuchungen zur Bedeutung der FeLV-Infektion für Erkrankungen bei Sektionskatzen.

Persistent FeLV infection was demonstrated in more than 3000 necropsied cats by an immunohistological method. The findings were associated with the diagnoses established by means of post-mortem examination, histopathological, bacteriological, virological, and parasitological investigations. Statistically significant differences between FeLV-positive and FeLV-negative cats in the relative risk for certain lesions could be demonstrated for the first time. As a consequence, the importance of FeLV infection for the development of certain lesions in cats is to be seen under new aspects for some diagnoses. The relative risk for development of anemia, e.g., is only slightly increased in FeLV-positive animals whereas the relative risk for focal myocardial necrosis and coccidiosis is elevated tremendously in these cats. The relative risk for some lesions and diagnoses is much higher in FeLV-negative cats than in FeLV-positive animals. This is true, e.g., for myocardiopathy and hemorrhagic cystitis.

Bound Water in Durum Wheat under Drought Stress.

To study drought stress effects on bound water, adsorption isotherms and pressure-volume curves were constructed for two durum wheat (Triticum durum Desf.) cultivars: Capeiti 8 (drought tolerant) and Creso (drought sensitive). Plants were grown under well-watered and water-stressed conditions in a controlled environment. Differential enthalpy (DeltaH) was calculated through van't Hoff analysis of adsorption isotherms at 5 and 20 degrees C, which allowed us to determine the strength of water binding. DeltaH reached the most negative values at approximately 0.06 gram H(2)O/gram dry weight and then increased rapidly for well-watered plants (until 0.10 gram H(2)O/gram dry weight) or more slowly for drought-stressed plants (until 0.15-0.20 gram H(2)O/gram dry weight). Bound water values from pressure-volume curves were greater for water-stressed (0.17 gram H(2)O/gram dry weight) than for well-watered plants (0.09 gram H(2)O/gram dry weight). They may be estimates of leaf moisture content where DeltaH reaches the less negative values and hence some free water appears. With respect to the well-watered plants, tightly bound water tended to be less bound during drought, and more free water was observed in cv Creso compared to cv Capeiti 8 at moisture contents >0.10 gram H(2)O/gram dry weight.

Long-term optimized embryogenic cultures in durum wheat (Triticum durum Desf.).

Five varieties of durum wheat: Appulo, Ofanto, Latino, Creso, and Castello (Triticum durum Desf.) adapted to the semi-arid mediterranean environment have been tested for their in vitro response. Compact, embryogenic, highly regenerable calli originated from primary callus derived through proliferation of the scutellum of immature embryos explanted in the presence of 2,4 dichlorophenoxyacetic acid. Selective subculture of the white, compact, embryogenic sectors led to the establishment of long-term cultures. Regeneration occurred on hormone-free medium either via germination of somatic embryos, or via multiple-shoot formation probably due to precocious germination of somatic embryos. The three varieties, Ofanto, Creso and Appulo, were the best responding genotypes. Callus fragmentation and two subsequent transfers onto fresh medium at 7-day intervals yielded a frequency of plant regeneration of some 25-40 plantlets per gram fresh weight callus in 21 days on Murashige and Skoog's hormone-free medium. Plantlets could be efficiently established in soil, thus confirming the possibility of biotechnological approaches with varieties of this crop species.