Ontogeny of Anabaenopsis raciboskii Wolosz. and Its Taxonomical Relevance

An annual life cycle, including 4 developmental stages, is discovered in Anabaenopsis raciborskii Wolosz of the West Lake, Hangzhou. The progress of these developmental stages is influenced by the enviroment. The third stage with heterocysts expressed distinctly as Anabaenopsis raciborskii Wolosz., and the fourth stage was formerly recognized as Raphidiopsis sinensis and R. curvata. It is considered based on these facts that Anabaenopsis raciborskii Wolosz., R. curvata Frit. et Rich. and R. sinensis Jao are different forms at dif-ferent stages of ontogeny, and ought be treated as a single species.     

Meteorological factors affecting the bloom of Anabaenopsis raciborskii Wolosz. (Cyanophyta:Hormogonales) in the shallow Lake Balaton, Hungary

There was a heavy bloom of a nitrogen-fixing blue-green algaAnabaenopsis raciborskii Wolosz. in Lake Balaton in September-October1982. The authors studied the dynamics of the phyto- and bacterio-plankton of the lake by daily and weekly samplings. Some meteorologicalfactors were also considered. It could be concluded that thecauses of the bloom were accumulating nutrients being enrichedjust before the bloom-period suddenly washed into the lake byheavy rains, followed by windless warm days (water temperatures26–29°C). An expressed correlation between bacterio-and phytoplankton indicates their close trophic relationship.     

Seasonal non-allergic rhinoconjunctivitis

Several patients suffering from seasonal rhinitis imitating treepollen induced hay fever, but who have negative tests with pollen allergens, have been investigated. In a retrospective study, 86 such patients with seasonal non-allergic rhinitis (SNAR) were compared with two other groups of patients: patients with birch pollen hay fever (BP) and patients with vasomotor rhinitis (VR). It was found that SNAR and VR compared to BP started at a later age, was more common in females and less often combined with hypersensitivity against nuts, apples and stone fruits. Flowers and strong smells more often elicited symptoms in SNAR than in VR and BP. The seasonal symptoms started earlier among SNAR than among BP patients. Positive skin tests with common inhalant allergens were much more common in BP than in SNAR. It is concluded that SNAR has more characteristics in common with VR than with BP. A probable explanation of the disease is a non-specific hypersensitivity to non-allergenic substances occurring in out-door air in spring, possibly air pollutants bound to pollen grains.     

Pigmented variants of Rhizobium

Summary Non-infective pigmented variants of Rhizobium have been isolated from several cultures after treatment with antibiotics, heat and U.V. irradiation. These variants tolerated much higher doses of heat, U.V. and certain antibiotics than the wild type strains from which they originated. Some of the pigmented variants produced reverse mutants on subculture which had lost their pigment but recovered their infectivity. These reverse mutants also lost their extreme U.V.-resistance. However, many pigmented mutants were very stable and reverted only after U.V. irradiation.This investigation shows that pigmentation in Rhizobium and loss of ability to form nodules on the roots of leguminous plants are genetically linked and may be pleiotropic effects. So far, more than 10 pigmented variants have been isolated, none of them was infective, while reverse mutants which had lost their pigment always gave rise to nodules.     

Collecting splice variants

A DNA array has been used to measure the affinity of wild-type and mutant variants of a zinc-finger-protein DNA-binding domain for all combinations of its binding site on DNA.

     

Seasonal abundance of psammon rotifers

Zonation and abundance dynamics of interstitial rotifers in a semilotic beach of the North Sea island of Sylt were studied in 1975/76. The 13 species investigated prefer the damp sand of the beach slope. The sand flat is only sparsely inhabited. Rotifers only live in oxygen-rich sands. Neither the black sulphite layer in the sand flat nor the groundwater in the beach slope is populated. The family Colurellidae prefers warm temperatures in mid-summer, the family Proalidae colder temperatures in spring and autumn. In contrast to these two families that can be found in different frequencies all year round, the family Dicranophoridae occurs only in the cold seasons and disappears in mid-summer. Possibilities of maintaining the life cycle during these months are discussed.