Faecal coliform bacteria (among others Escherichia coli) are routinely used in monitoring of water areas (first of all seaside resorts). Their occurrence indicates recent pollution by municipal sewage. Survival of these bacteria in the sea water depends on the complex of biological, chemi-cal and physical water parameters. There are many conflicting opinions on bacterial death-rate and the data on this phenomenon for the Gulf of Gdansk are rather scarce. The influence of irradi-ance (0-200 mumol photon m-2 s-1), temperature (5-20 ?C) and salinity (0-7.5 psu) on the survival of Escherichia coli strain K-12 has been investigated. The bacterial cultures were incubated for three days under chosen temperature, salinity and irradiance conditions. Experiments were planned based on the factorial design (method x'). The cell density was determined every day by direct viable count on agar plates. The obtained results were analysed statistically in such a way that temperature, salinity and irradiance were independent variables whereas Escherichia coli number and mean mortality coefficient (Km) were the dependent ones. It was found that the effect of salinity (in studied range from 0 to 7.5 psu) on Escherichia coli survival was not statistically significant. However, the survival was strongly correlated with temperature and irradiance. Correlation coefficient (R) between temperature and irradiance and mean coefficient of Escherichia coli mortality (Km) equalled 0.801. This dependence can be described by a function, obtained from nonlinear regression analysis, Km = 6.466 - 0.195 t + 2.215?10-7 t2 i2. The function will be used for the development of a model of matter circulation and energy flow in the Gulf of Gdansk.
Allergic asthma is characterized by a temporally and quantitatively inappropriate immunologic response. One of hallmarks of this response is the accumulation of eosinophils in the airway and lung parenchyma, which results in bronco-constriction, lung damage and ultimately fibrosis. GM-CSF plays a pivotal role in this process by modulating eosinophil function and survival. In this review, we discuss the effects and molecular regulation of GM-CSF secretion by eosinophils. Recent data demonstrate activated eosinophils release small amounts of anti-apoptotic GM-CSF by stabilizing its coding mRNA.
Rho kinase (ROCK) belongs to a family of serine/threonine kinases that are activated via interaction with Rho GTPases. ROCK is involved in a wide range of fundamental cellular functions, such as contraction, adhesion, migration, and proliferation. Recent studies have shown that ROCK plays an important role in the regulation of apoptosis in various cell types and animal disease models. Two ROCK isoforms, ROCK1 and ROCK2, are assumed to be function redundant, this based largely on kinase construct overexpression and chemical inhibitors (Y27632 and fasudil) which inhibit both ROCK1 and ROCK2. Gene targeting and RNA interference approaches allow further dissection of distinct cellular, physiological, and patho-physiological functions of the two ROCK isoforms. This review, based on recent molecular, cellular, and animal studies, focuses on the current understanding of ROCK signaling in the regulation of apoptosis and highlights new findings from recently generated ROCK-deficient mice.
The fate of organ transplants between unrelated individuals of the same species is almost always to be rejected, unless the recipient receives immunosuppressive drugs. Liver transplants are an exception, as in a number of animal models, they are often accepted without requiring any treatment. Several mechanisms have been proposed for liver transplant acceptance including: the vascular structure of the liver which allows interaction between na?ve T cells and liver parenchymal cells; the atypical leucocyte populations of the liver particularly immature dendritic cells; neutralisation of rejection by donor soluble MHC antigen; establishment of microchimerism by donor haematopoietic stem cells and death by ?neglect? of recipient T cells in response to inappropriate activation by donor liver leucocytes. Although all these mechanisms may contribute to liver acceptance to some degree, an important finding is that liver acceptance appears to be mainly due to donor leucocytes transplanted with the liver. In combination with the observation of rapid T cell activation followed by their death after liver transplantation, these findings have identified a prominent role for donor leucocyte-induced deletion of liver-reactive T cells. These findings suggest novel ways to explore improved treatment for transplant patients, including administration of donor leucocytes at the time of transplantation and delay of some components of immunosuppressive drug induction therapy.
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