Simulation modeling of phytoplankton dynamics in a large eutrophic river,Hungary — Danubian Phytoplankton Growth Model (DPGM)

Ecological models have often been used in order to answer questions that are in the limelight of recent researches such as the possible effects of climate change. The methodology of tactical models is a very useful tool comparison to those complex models requiring relatively large set of input parameters. In this study, a theoretical strategic model (TEGM) was adapted to the field data on the basis of a 24-year long monitoring database of phytoplankton in the Danube River at the station of Göd, Hungary (at 1669 river kilometer - hereafter referred to as “rkm”). The Danubian Phytoplankton Growth Model (DPGM) is able to describe the seasonal dynamics of phytoplankton biomass (mg L^?1) based on daily temperature, but takes the availability of light into consideration as well. In order to improve fitting, the 24-year long database was split in two parts in accordance with environmental sustainability. The period of 1979–1990 has a higher level of nutrient excess compared with that of the 1991–2002. The authors assume that, in the above-mentioned periods, phytoplankton responded to temperature in two different ways, thus two submodels were developed, DPGM-sA and DPGM-sB. Observed and simulated data correlated quite well. Findings suggest that linear temperature rise brings drastic change to phytoplankton only in case of high nutrient load and it is mostly realized through the increase of yearly total biomass.     

Draft genome sequence of an efficient antibiotic-producing industrial strain of Saccharomonospora azurea, SZMC 14600

Although certain rare actinomycetes have been recognized as prolific sources of bioactive natural products, their potential for producing biologically active metabolites still remains unexplored. With the aim of gaining global insights into the genetic background and the metabolic capability of Saccharomonospora azurea SZMC 14600, whole-genome sequencing was performed.     

The role of field coupling in nano-scale cellular nonlinear networks

We review some of our previous work on field-coupling in nano-scale cellular arrays. Electronic devices based on metallic and magnetic nanoscale dots and molecular structures have been suggested, however, no technologically viable architecture for nanoelectronic circuit integration has emerged so far. A natural architecture on the nanoscale appears to be near-neighbor cellular networking, and we explore promising alternative ways of integrating nanodevices by direct physical field coupling, i.e. either by Coulomb or by magnetic interactions. We review new architectures for such field-coupled nanocircuits.     

Hydrolytic behavior of 5alpha-hydroxy-11beta- and 5beta-hydroxy-11alpha-substituted 19-norsteroids

Teutsch G. and Bélanger A. treated 5alpha,10alpha epoxides with Grignard-reagents catalyzed by copper(I) ions. The reaction with steroidal epoxides proceeded with complete regio- and stereospecificity, leading exclusively to the 11beta-substituted compounds. According to our synthetic strategy, the 5,10 epoxide isomers were not separated; instead, the pure 11beta, and in some cases, 11alpha-substituted molecules were isolated after the conjugate addition of the Grignard-reagents, followed by deketalization and dehydration. Surprisingly, appearance of a third compound was generally observed beside the expected deprotected products, and this compound turned out to have a 3-keto-5(10),9(11) structural unit. Starting from pure 3-ethylenedioxy-5alpha,10alpha-epoxy-estr-9(11)-ene-17-one and 3-ethylenedioxy-5beta,10beta-epoxy-estr-9(11)-ene-17-one, four model compounds were synthesized (11alpha- and 11beta-[4-[1,1-(ethylenedioxy)-ethyl]phenyl]-estra-, as well as 11alpha- and 11beta-cyclohexyl-estra-derivatives) to study the process of deprotection and dehydration. 3-keto-5(10),9(11)-derivatives were found to form after deketalization and dehydration only from 11alpha-substituted derivatives, while 11beta-derivatives resulted in only the expected 3-keto-5,9-diene structure. After observing this remarkable difference between the behavior of 11alpha-, 11beta-substituted isomers we decided to take a closer look at the processes of deketalization and dehydration. In order to carry out the hydrolysis under mild conditions, pyridinium paratoluenesulfonate, a weakly acidic salt, was applied. All the intermediate products observed by TLC were isolated. The outcome of the deprotection and elimination reactions can be rationalized by two factors: conjugation of olefins (with the 3-oxo-group or the 11-phenyl group) and orientation of groups to be eliminated.     

Effect of poly(ADP ribose) synthetase inhibition on burn and smoke inhalation injury in sheep

We investigated the role of the nuclear enzyme poly (ADP ribose) synthetase (PARS) in the pathogenesis of combined burn and smoke inhalation (burn/smoke) injury in an ovine model. Eighteen sheep were operatively prepared for chronic study. PARS inhibition was achieved by treatment with a novel and selective PARS inhibitor INO-1001. The PARS inhibitor attenuated 1) lung edema formation, 2) deterioration of gas exchange, 3) changes in airway blood flow, 4) changes in airway pressure, 5) lung histological injury, and 6) systemic vascular leakage. Lipid oxidation and plasma nitrite/nitrate (stable breakdown products of nitric oxide) levels were suppressed with the use of INO-1001. We conclude that PARS inhibition attenuates various aspects of the pathophysiological response in a clinically relevant experimental model of burn/smoke inhalation injury.     

Gender differences in the histamine and serotonin content of blood,peritoneal and thymic cells: a comparison with mast cells

The serotonin and histamine content of mast cells and white blood cells in adult male and female rats was compared, using a flow cytometric immunological method. Serotonin was significantly higher in female peritoneal mast cells, peritoneal monocyte-ganulocyte-macrophage cells, blood lymphocytes and blood thymocytes. Histamine was significantly higher in female peritoneal monocyte-granulocyte-macrophage cells, and blood lymphocytes, monocytes and granulocytes, but was significantly less in thymocytes. Peritoneal lymphocytes and the monocyte-granulocyte-macrophage group contained significantly more histamine than mast cells. These experiments call attention to gender differences in the levels of biogenic amines in cells participating in defence reactions, and to the possible non-unique role of mast cells in serotonin and histamine supply.     

CD4<Superscript>+</Superscript>CD25<Superscript>+</Superscript> immunoregulatory T cells may not be involved in controlling autoimmune arthritis

Accumulating evidence suggests that regulatory T cells play a crucial role in preventing autoimmunity. Recently, a naturally occurring CD4⁺CD25⁺ T-cell subset that is anergic and also suppressive has been shown to suppress autoimmunity in several animal models. We used proteoglycan-induced arthritis (PGIA) as a study model to investigate the role of the CD4⁺CD25⁺ regulatory T cells in autoimmune arthritis. There was no significant change in the percentage of CD4⁺CD25⁺ T cells during the immunization period when proteoglycan- or ovalbumin-immunized BALB/c and C57BL/6 mice were compared. An adoptive transfer study showed that the CD4⁺CD25⁺ T cells did not protect severe combined immunodeficient mice from arthritis when they were cotransferred with splenocytes from arthritic animals. Similarly, depletion of the CD4⁺CD25⁺ T cells did not enhance the onset of the disease or disease severity in severe combined immunodeficient mice. Moreover, CD28-deficient mice, which have very few CD4⁺CD25⁺ T cells, were highly resistant to PGIA. These findings indicate that the CD4⁺CD25⁺ regulatory T cells may not play a critical role in controlling PGIA.     

Impaired cumulus mucification and female sterility in tumor necrosis factor-induced protein-6 deficient mice

Mucification of the cumulus layer around the oocyte is an obligatory process for female fertility. Tumor necrosis factor-induced protein-6 (TNFIP6 or TSG6) has been shown to be specifically expressed during this process. We have generated TNFIP6-deficient mice and tested the ability of their cumulus cells to undergo mucification. Cumulus cell-oocyte complexes fail to expand in TNFIP6-deficient female mice because of the inability of the cumulus cells to assemble their hyaluronan-rich extracellular matrix. The impaired cumulus matrix formation is due to the lack of covalent complexes between hyaluronan and the heavy chains of the inter-alpha-trypsin inhibitor family. As a consequence, TNFIP6-deficient females are sterile. Cultured TNFIP6-deficient cumulus cell-oocyte complexes also fail to expand when stimulated with dibutyryl cyclic AMP or epidermal growth factor. Recombinant TNFIP6 is able to catalyze the covalent transfer of heavy chains to hyaluronan in a cell-free system, restore the expansion of Tnfip6-null cumulus cell-oocyte complexes in vitro, and rescue the fertility in Tnfip6-null females. These results provide clear evidence that TNFIP6 is a key catalyst in the formation of the cumulus extracellular matrix and indispensable for female fertility.