Polymorphism and Ultrastructure of a Colpodean Ciliate of the Genus Platyophryides Foissner, 1987

ABSTRACT. A ciliate isolated from a pond in Brazil, transformed to a giant form when its food was shifted from a bacterial prey to a ciliate prey. This polymorphism is immediately reversible when the prey ciliates, either Tetrahymena or Colpidium , disappear from the culture medium. By its life cycle, morphology, and ultrastructure, this ciliate belongs to the Class Colpodea. it could belong to the genus Platyophryides Foissner, 1987, except that its micronucleus is not enveloped by the macronuclear membrane. The systematic position of the genus Platyophryides , the validity of the three species in this genus, and the characteristics of the Cyrtolophosidida are discussed.     

On the origin and colonization of house mice in the Madeira Islands

The skulls and skins of adult house mice from the Madeira Islands have been studied and compared with those from the Salvage Islands and with material from the neighbouring Portuguese mainland man-associated and wild forms, respectively Mus musclus domesticus Rutty, 1772 and M. sprelus Lataste, 1883. Differences between island and mainland populations were found in some of the analysed features. Insular skins of mice were found to be smaller than those of specimens from the mainland. However, in Madeiran and Salvage mice the toothrows were much more developed than in the mainland house mice. It is considered that the causes of these differences lie in the different characteristics of the habitats, mainly food availability, and also in the isolation of populations. Mus musculus domesticus appears to be the only form of the house mouse to have so far successfully colonized the Madeiras.     

A Comparison of the Use of In Vitro-Transcribed and Native rRNA for the Quantification of Microorganisms in the Environment

Abstract Nearly full-length, small subunit (SSU) rRNA was transcribed in vitro from clones of SSU rDNA genes. Comparing the use of in vitro-transcribed and native rRNA indicated that, when in vitro-transcribed rRNA was used as a standard for quantitative hybridizations with oligonucleotide probes, the population was consistently underestimated. The population abundance was expressed as a percentage of specific target SSU rRNA (determined with a specific oligonucleotide probe), relative to the total SSU rRNA (measured with a universal probe). Differences in hybridization signals could be related to specific probe target locations and rRNA denaturation conditions, suggesting that higher order structure is important in quantitative membrane hybridizations. Therefore, in vitro-transcribed rRNA cannot always be used for the absolute quantification of microbial populations, but can be employed as a standard to quantify shifts in population abundance over time, and to compare community structure in various environments.     

The role of HSP70 and Ca(2+)-pump from the myocardial sarcoplasmic reticulum in cardioprotective effects during adaptation to physical load in rats

In the course of adaptation to exercise, enhanced resistance of isolated heart against ischemia and reperfusion correlated with accumulation of cytoprotective proteins of the HSP70 family and increased potency of sarcoplasmic reticulum (SR) Ca2+ pump in the rat myocardium. Blockade of the HSP70 synthesis with guercetin prevented development of protection of the heart against ischemia and reperfusion. In the course of the adaptation, the increased resistance of the Ca2+ pump against detrimental factors preceded its potentiation. The findings suggest that the HSP70 accumulation and increased potency and resistance of the SR Ca2+ transport system in the myocardium are important mechanisms of adaptive protection of the heart.     

Plasma sialyltransferase activity in healthy subjects and atherosclerotic patients

Plasma sialyltransferase activity measured by incorporation of cytidine 5;-phospho[14C]acetylneuraminic acid (CMP-NeuAc) into asialofetuin was twofold higher in patients with documented atherosclerosis than in healthy donors. Kinetic studies showed that the enzyme affinity for CMP-NeuAc is the same in donors and patients. Low activity of plasma sialyltransferase in donors may be due to low blood content of this enzyme.     

Fertility table and rate of population growth of the predator Supputius cincticeps (Heteroptera: Pentatomidae) on one plant of Eucalyptus cloeziana in the field

The reproductive potential and population growth (r_m and λ) of the predator Supputius cincticeps (Heteroptera: Pentatomidae) were evaluated using a life and fertility table. S. cincticeps was reared on one plant of Eucalyptus cloeziana in the field and fed with Tenebrio molitor (Coleoptera: Tenebrionidae) pupae. Females of this predator had a net reproductive rate (R₀) of 21.02 females/female; an intrinsic rate of population increase (r_m) of 0.041 and finite rate of increase (λ) of 1.042. This resulted in population growth of S. cincticeps in the eucalyptus plant with a doubling time of 17.01 days. This natural enemy can be reared under field conditions with alternative prey for use in biological control. Such individuals of S. cinticeps will be better adapted to field conditions when they are liberated.     

Levels of the upper forest boundary in northern Asia

On the Ural range the elevation of upper timberline changes at grade 71 m per degree of latitude in linear regression. Much lengthy cross-section—for the semi-arid regions of middle Siberia and adjacent Kazakhstan, and for the regions of eastern Siberia dominated by larch forests—exhibit parabolic regression of timberline levels upon geographic latitude. The longitudinal gradient of timberlines presumably depends on radiation balance related with the amount of precipitation. The arctic boundary of taiga in eastern Europe and Siberia lies mostly on average latitude 69° 36 E. It correlates with mean July temperature 11.2 °C, or with duration of the growing season 128 days with stable temperature of air exceeding 0°C which amounts to 876°. Daily temperatures exceeding 5° and especially 10 °C are seemingly less influential there. The value of 11.2 °C deviates by about 1 °C from the value of above 10 °C for three summer month reported by Langlet 1935, which shows the close environmental control regulating the northern and upper boundary of the northern, mostly coniferous forest on the northern hemisphere.