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Sexual reproduction in yeasts has a survival function by providing an alternative to the vegetative processes when conditions are no longer conducive for growth. If both sexes are in the correct physiological state (usually under starvation conditions), then initiation of copulation involves the mutual induction of a sexual response. This response is mediated by diffusible compounds and by physical contact. Initial cell contacts between opposite mating types can be disrupted easily, but stronger intercellular bonds form later that result in the fusion of two cells into one. Union between mates involves mixing of parental gene pools. The new diploid organism or its subsequent offspring might be better equipped to survive in a new environment because they may contain new combinations of parental genes. Hence, sex is more advantageous to the survival of the species than it is to the individual organism. The purpose of this review is to compare the steps in the mating process in three species of yeasts. The various physiological factors, events and regulatory phenomena that are part of the mating process will be described for Hansenuta wingei, Schizosaccharomyces pombe and Saccharomyces cerevisiae in Sections II, III and IV, respectively. Then, in Section V, the similarities and differences among these yeast systems will be discussed. Emphasis in this article will be on recent observations since reviews of earlier work are available for each mating system (for H. wingei: Crandall and Brock, 1968; Crandall and Caulton, 1975; for Schizosacch. pombe: Leupold, 1970; Gutz et at., 1974; for Sacch. cerevisiae: Fowell, 1969a, b; Bilinski et at., 1975; Sena et at., 1975). For a comprehensive review of conjugation in all yeasts, fungi and other micro-organisms, consult Crandall (1977). The three yeasts to be reviewed here are quite diverse in terms of their ecological niches, metabolism, morphology and life cycles. Therefore, for a better understanding of the physiology of sexual reproduction in these organisms, it is necessary first to consider these characteristics. A more detailed description of each yeast is given in Lodder (1970).
Four new species of the genus Sokoloviana (Pterolichoidea; Ptiloxenidae) from waders suborder Charadrii (Charadriiformes) are described: Sokoloviana cornuta sp. nov. from the Banded Stilt, Cladorhynchus leucocephalus; Sokoloviana ibidorhynchae sp. nov. from the Ibis-bill, Ibidorhyncha strutersi; Sokoloviana chilensis sp. nov. from the Southern Lapwing, Vanellus chilensis and Sokoloviana vanelli sp. nov. from the Red-wattled Lapwing, Vanellus indicus atronuchalis. A key to all described species is given.
In this article we examine and "exapt" Wurzel's concept of superstable markers in an innovative manner. We develop an extended view of superstability through a critical discussion of Wurzel's original definition and the status of marker-superstability versus allomorphy in Natural Morphology: As we understand it, superstability is - above and beyond a step towards uniformity - mainly a symptom for the weakening of the category affected (cf. 1.,2. and 4.). This view is exemplified in four short case studies on superstability in different grammatical categories of four Germanic languages: genitive case in Mainland Scandinavian and English (3.1), plural formation in Dutch (3.2), second person singular ending -st in German (3.3), and ablaut generalisation in Luxembourgish (3.4).
Background: Bacterial meningitis is associated with high mortality and long-term neurological sequelae. Increasing the phagocytic activity of microglia could improve the resistance of the CNS against infections. We studied the influence of activin A, a member of the TGF-β family with known immunoregulatory and neuroprotective effects, on the functions of microglial cells in vitro.
Methods: Primary murine microglial cells were treated with activin A (0.13 ng/ml–13 μg/ml) alone or in combination with agonists of TLR2, 4, and 9. Phagocytosis of Escherichia coli K1 as well as release of TNF-α, IL-6, CXCL1, and NO was assessed.
Results: Activin A dose-dependently enhanced the phagocytosis of Escherichia coli K1 by microglial cells activated by agonists of TLR2, 4, and 9 without further increasing NO and proinflammatory cytokine release. Cell viability of microglial cells was not affected by activin A.
Conclusions: Priming of microglial cells with activin A could increase the elimination of bacteria in bacterial CNS infections. This preventive strategy could improve the resistance of the brain to infections, particularly in elderly and immunocompromised patients.
Effects of BPA in snails
(2006)
It is an ethical requirement that new findings be presented in light of and in conjunction with a balanced evaluation of the current knowledge and published literature. We believe that Oehlmann et al. (2006) violated this general principle in several ways. For example, the authors inferred that prosobranch snails have a functional estrogen receptor and therefore a much higher sensitivity to estrogens and endocrine-disrupting compounds (EDCs) than other species previously reported in the literature. We found several other problems in their article...
The Invertebrate section of the Museum of Zoology QCAZ at the Pontifical Catholic University of Ecuador in Quito maintains nearly two million curated specimens, and comprises Ecuador's largest collection of native taxa. We review 1902 type specimens from 6 subspecies and 320 species in 121 genera and 42 families, currently kept in the Museum. The list includes 116 holotypes, 10 allotypes, 1774 paratypes and 2 neoparatypes. The collection of type specimens is particularly strong in the Coleoptera (family Carabidae and Staphylinidae) and Hymenoptera. However, other insect orders such as Diptera and Lepidoptera and non-insect arthropods such as Acari, Aranea and Scorpiones, are moderately represented in the collection. This report provides original data from labels of every type specimen record. An analysis of the geographic distribution of type localities showed that collection sites are clustered geographically with most of them found. towards the northern region of Ecuador, in Pichincha, Cotopaxi and Napo provinces. Sites are mainly located in highly accessible areas near highways and towns. Localities with a high number of type species include the cloud forest reserve Bosque Integral Otonga and Parque Nacional Yasunf in the Amazon rainforest near PUCE's Yasuni Scientific Station. Type localities are not well represented in the Ecuadorian National System of Protected Areas. Future fieldwork Sllould include. localities in the southern region of Ecuador but also target less accessible areas not located near highways or towns. We discuss the value of the collection as a source of information for conservation and biodiversity policies in Ecuador.
Notes on irish plants
(1909)
"The death of the Emperor Frederick Il in 1250 marked a tuming point in German affairs. When in 1212 the young King of Sicily had taken Germany by storm, driving north his Welf rival Otto IV of Brunswick and securing the support of the German princes, it had seemed that a new golden age had begun. Walther von der Vogelweide at last received his "lêhen", and praised his new patron as "der edel künec, der milte künec". ln Aachen a crusade was proclaimed for the liberation of Jerusalem. Comparisons were made with the Emperor's grandfather, Frederick Barbarossa. The house of Hohenstaufen was again in the ascendency. But these high expectations were always unrealistic. Frederick's crusading vows became a thom in his flesh; his enemies held him to them, but obstructed him as he sought to fulfil them. Much of his energy was taken up in a dual struggle against insurgency in his restive Lombard states, and against the bitter invective of the papal propagandists. Although Innocent lll had been the prime sponsor of the young Emperor, Honorius III became alan·ned at the prospect of a union of the crowns of Sicily and the Empire, and Gregory IX and Innocent IV became determined to break the power of the Hohenstaufen dynasty once and for all. The popes did not have it all their own way. For the most part, the German princes remained loyal, pleased to have an emperor who interfered so little in their affairs. Frederick‘s policy of diplomacy and compromise attracted more sympathy than that of the Pope who refused to meet and treat with him. His early death, however, left his son Conrad IV in a weak position from which he was unable to recover, and within twenty years the last Hohenstaufen rulerwas deposed. The impact of these events on the intellectual climate in Germany was immense. After Frederick's death, there was an upsurge in apocalyptic preaching, and much of the literature of the period was diffused with a sense of nostalgia. It is in this light that we must read the account of the life of Frederick II which is offered by the Viennese patrician, Jansen Enike. Enikel‘s Universal Chronicle ('Weltchronik') recounts the history of the world from Adam to Frederick. It was written about 1272, just four years after the death of Conradin, the last of the Staufen line. Enikel was probably born in the 1230s, and his own lifespan exactly coincided with the years of Hohenstaufen decline. His account ol Frederick's life has limited value as history, but casts an interesting sidelight on the confusion of impressions which had gathered in popular lore. In keeping with the rest of his chronicle, it is anecdotal, falling naturally into ten sections of differing lengths, most of which are to some extent self-contained units. Together, these fill over thirteen hundred lines, making Frederick Enikel's most comprehensively treated post-biblical protagonist; only Moses and David are dealt with at greater length."