Distribution and dispersal capacity of the Ponto-Caspian tubificid oligochaete Potamothrix moldaviensis Vejdovský et Mrázek, 1903 in the Baltic Sea Region

Over the last few centuries, several Ponto-Caspian tubificid oligochaetes have gradually dispersed from the Black Sea – Caspian Sea region to the north-west and west over Europe. The present world distribution comprising also the Great Lakes of North America clearly demonstrates that anthropochorous vectors of dispersal are involved. Passive transportation in the ballast water of ships has radically changed the possibilities of dispersal for many invertebrate species and has even made dispersal between continents possible. The construction of navigable canals has furthermore facilitated the crossing of watersheds and continents. Other likely vectors of longway dispersal for oligochaetes, as well as for other small-size aquatic invertebrates, are birds and mammals. The dispersal of the Potamothrixspecies is likely to have taken place in successive waves (three) with front-lines still on the move from the east to the west over the Baltic States and Scandinavia. The rheophilous species Potamothrix moldaviensishas presently reached – apart from the large rivers of Russia and many Central-European water bodies – also the Baltic States and south-eastern Sweden. Trajectories of dispersal demonstrate routes across the Baltic Sea – via the ballast water of ships. In the largest rivers of the Eastern Baltic Region (Neva, Daugava, Nemunas), downstream dispersal is the most likely way of transportation. P. moldaviensis together with P. heuscheri(second wave) and P. vejdovskyi(third wave) are presently forming front-lines running obliquely from the north-east to the south-west over south Sweden. In mesotrophic-eutrophic basins of eastern Lake Mälaren, the abundance as well as the species diversity of oligochaetes is particularly high wherever Ponto-Caspian Potamothrixspecies – often several species together – are involved.     

Temporal processes and duck populations: examples from Mývatn

Studies of temporal processes at Lake Mývatn, Iceland, on three scales, millennial, centennial and decadal, are reviewed and a summary is presented of the main results of waterfowl population monitoring studies conducted during the past three decades. The characteristics of shallow, subarctic Lake Mývatn and its volcanic environment, are outlined, as well as recent conflicts between development and conservation. Mining of the bottom sediment of Lake Mývatn has been a major agent causing habitat destruction and damage to the food web. Population limitation of waterbirds at Mývatn is discussed, as three research questions and emerging answers: (1) How is reproductive output determined? All species studied showed positive correlations of production of young with levels of aquatic insects, catastrophic weather was rarely important; (2) How is the dispersion of breeding ducks determined? Densities of migratory species are determined mainly by resource levels on the breeding ground in the year before they return to the breeding area; a year-round resident species, Bucephala islandica, adjusts its density to the current availability of insect food in each of two main habitats used; (3) How are flyway populations of ducks determined? For most species, there is not enough information on total numbers and the state of the habitat on a flyway scale. In B. islandica, there are indications that the total population is limited by resources in winter. The Mývatn study area is dominated by a single, shallow and eutrophic lake and for many waterbird species the area seems to form a single functional unit. This leads to significant correlations when comparing demography with environmental conditions, such as food resources.     

Inheritance of some leaf characters inSalvia němecii HBý

Mezidruhový hybridSalvia němecii (S. nutans x 8. juri?i?ii), popsaný autorem ji? d?íve, je plně plodný. Proto byly na 238 rostlinách F₂ generace sledovány tyto znaky: typ svazk? cévních v 159;apíku, poměr délky ?apíku k délce ?epele, délko?í?kový index ?epele listové a ?lenitost ?epele, vyjád?ená poměrem ideální obrysové ploehy listu k jeho skute?né plo?e. V?ecky tyto charakteristiky srovnány se situací u rodi?ovských druh? i F₁ hybrida. Bylo zji?těno:

1. 1.
   Typ II svazk? cévních je jednodu?e a úplně dominantní nad typem III (?těpný poměr 172 : 66, X²(1) = 0.94, p =0–35).,     
   
   

Radicaux libres et spermatozoïdes humains: physiologie et physiopathologie

The role of reactive oxygen species in the physiopathology of human sperm function has been emphasized in recent years. Their production in semen has been associated with loss of motility, decreased capacity for spermoocyte fusion and loss of fertility. In semen preparations, there are two major sources of reactive oxygen species: leucocytes and spermatozoa themselve. It has been proposed that reactive oxygen species production by human spermatozoa was dependent upon a membrane-bound NADPH oxidase or a mitochondrial diaphorase. Hydrogen peroxide produced by the dismutation of superoxide anion has been recognized as the most toxic oxidizing species for human spermatozoa. Owing to their high content of polyunsaturated fatty acids, it has been proposed that lipid peroxidation of the sperm plasma membrane is largely responsible for defective sperm function. Reactive oxygen species also affect the sperm axoneme as a result of ATP depletion, inhibit mitochondrial functions, and synthesis of DNA, RNA and proteins, produce cytoskeletal modifications and inhibit sperm-oocyte fusion. Human spermatozoa possess enzymatic defence systems such as superoxide dismutase, glutathion peroxidas/reductase and catalase to counteract the toxic effects induced by reactive oxygen species. Correlations have been reported between their effectiveness and the duration of sperm motility. If the excessive production of reactive oxygen species is detrimental for human spermatozoa, they could also participate in the physiological function of the spermatozoa when present at low concentrations. Indeed, reactive oxygen species have been shown to be involved in the activation of several enzymes. Furthermore, sperm capacitation, acrosome reaction and sperm-zona interaction would be enhanced by reactive oxygen species.     

Význam sensibilisace při experimentální stafylokokové infekci

Резюме Исследовалось течен ие внутрикожной стаф илококковой инфекции у кроликов,-к ак нормальных, так и акти вно сенсибилизирова нных повторными инфекция ми и пассивно сенсиби лизированных сенсибилизированны х клетками селезенки и перитонеального экс судата сенсибилизированны х животных. Для развити я стафилококковой ин фекции имеет значение повыш енная чувствительно сть позднего (туберкулин ового) типа, могущая пе реноситься клетками. В сенсибили зированной ткани инфекция проте кает интенсивнее и дл ительнее, с более массивным и дли тельным сохранением микробо в в ткани, чем у контрол ьных кроликов. Эти результ аты подтверждают значение сенсибилиз ации для патогенеза стафилококковой инф екции.

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The significance of sensitization in experimental staphylococcal infection II. Průběh místni infekce při aktivní a pasivní sensibilisaciII. The course of local infection in actively and passively sensitized rabbits

Souhrn Sledovali jsme průběh intradermální stafylokokové infekce u králiků normálních, aktivně sensibilisovanych opakovanymi infekcemi a pasivně sensibilisovanych buňkami sleziny a peritoneálního exsudátu sensibilisovanych zvířat. Přecitlivělost pozdního (tuberkulinového) typu, přenosná buňkami, má vyznam pro rozvoj stafylokokové infekce. Infekce v sensibilisované tkáni probíhá intensivněji a déle, s větším a trvalejším udrzením mikrobů v tkáni nez u králí ků kontrolních. Tyto vysledky potvrzují vyznam sensibilisace pro patogenesu stafylokokové infekce. Summary The author studied the course of intradermal staphylococcal infection in normal rabbits, in rabbits made hypersensitive by repeated staphylococcal infections and in rabbits passively sensitized by the administration of spleen cells and peritoneal exudate from hypersensitive animals. Hypersensitivity to staphylococcal antigen of the delayed (tuberculin) type, which can be transmitted by cells, is important in the development of staphylococcal infection. In sensitized tissue the course of the infection is more intensive and longer, and the bacteria remain in the tissues in larger numbers and for a longer period than in the controls.

     

Risques et valorisation des insectes dans l’alimentation humaine et animale

In a context of dwindling lands and resources, associated with a strong dependence on protein for feed and food, new methods of production and/or new food must be developed without affecting the quality of food, natural habitat and biodiversity of animal and vegetable species. As such, insects appear more and more as a solution of the future. To date, the consumption of insects is indicated by the term “entomophagy”, from the Ancient Greek “entomos” meaning insect and “phagos” meaning food. In such a context, a global evaluation of entomophagy seems essential before allowing the introduction of this practice in animal and human feed. Firstly, through this review, elements concerning the potentialities of insect valorization and their nutritional qualities will be brought. Secondly, the environmental impact of such a practice as well as the biological, chemical, physical or sanitary risks and even the potential presence of allergens and antinutritional factors will be approached. Thirdly, a review of the current European regulations will be proposed. Finally, reflections will be brought on the economic perspectives of entomophagy.     

Die Wald- und Baumgrenze im Gebirge Hrubý Jeseník (Hohes Gesenke), Tschechoslowakei

Die vorliegende Arbeit befasst sich mit dem Verlauf der oberen Wald- und Baumgrenze im Gebirge Hrubý Jeseník (Hohes Gesenke), die hier von der Fichte gebildet wird. Es wurden die wichtigsten, die Grenze beeinflussenden Faktoren analysiert. Die Frage der Ursprünglichkeit der Bestände an der Wald- und Baumgrenze wurde auf Grund von phytometrischen und morphologischen Beobachtungen festgestellt (Abnahme der Baumhöhe, Länge der Zuwächse, Beschädigung der Fichte durch Wind und Eis, Zahl, Länge und Ausdauern der Nadeln, Verjüngung der Fichte). Die Baumgrenze erwies sich für eine Beurteilung der potentielen Waldgrenze als geeignet.     

Radiopharmaceutiques et réglementations

The radiopharmaceuticals are products that combine two very stringent regulatory requirements from two different authorities: as medicine from a pharmaceutical point of view (Afssaps) and as radioactive source with specific authorization (ASN). This article discusses the different regulatory constraints imposed by these authorities but suggests also that legislation is supposed to be modified in the coming years in collaboration with nuclear physicians and their Society (SFMN).