Methanogenic bacteria as a key factor involved in changes of town gas stored in an underground reservoir

Growth of Phanerochaete chrysosporium in a nitrogen-limited medium buffered with sodium acetate, instead of the commonly used 2,2-dimethylsuccinate (DMS), resulted in quantitative and qualitative differences in the production of various extracellular lignin peroxidases (LIPs) and manganese-dependent peroxidases (MNPs) involved in lignin degradation. The results indicate that production of LIPs and MNPs can be selectively enhanced by manipulation of culture conditions. Partial N-terminal analyses of the major LIPs and MNPs have made it possible to assign a specific protein to the specific genes and cDNAs that have been reported recently. The LIPs and MNPs differed widely in their ability to decolorize various dyes that are known to be degraded by the lignin degrading enzyme system of P. chrysosporium.     

Actinobacillus septicemia in a black swan (Cygnus atratus).

A species of Actinobacillus was isolated in pure culture from the carcass of a captive Australian black swan (Cygnus atratus) dying of acute septicemia. The gross and microscopic findings are described and the significance of the isolate is discussed.     

Water balance comparison of two small experimental basins with different vegetation cover

In a river, the flow directly affects the physical and chemical properties of its water, with further consequences for aquatic biota. Land use practices and vegetation cover play a significant role in the water cycle. The wide-spread perception of forest cover, in terms of hydrology is that forests may reduce water runoff: although in rare instances the contrary has been reported. Water runoff varies seasonally and depends on the forest tree species. By no means can it be considered constant over large expanses of area or for various rainfall patterns. In this paper, the results of a long-term hydrological survey conducted in two experimental microbasins (operated by the Institute of Hydrology SAS, IH SAS) with different land use practices are presented. The Rybárik microbasin (0.119 km²) is dominated by row crop production. The basin was 70% cultivated by the state farm and 30% by a private farm. The Lesny microbasin (0.086 km²) is covered by a deciduous hornbeam regrowth forest (Carpinus betulus). The analysis revealed that the difference in the runoff from the forest and the agricultural land increases with increasing precipitation; however, at some point (extreme precipitations with low probability) the runoff from these basins is nearly equal.     

A standard tissue as a control for histochemical and immunohistochemical staining

The variable quality of histochemical and immunohistochemical staining of tissues may be attributed to pre-analytical and analytical variables. Both categories of variables frequently are undefined or inadequately controlled during specimen collection and preparation. Pre-analytical variables may alter the molecular composition of tissues, which results in variable staining; such variations may cause problems when different tissues are used as staining controls. We developed a standard tissue for use as a staining control. Our standard tissue contains five components: 1) nine combined human cell lines mixed with stroma from human spleen; 2) a squamous cancer cell line, A431; 3) fungus; 4) transverse sections of the mosquitofish and 5) normal human spleen. The first three components were embedded in HistoGel^? and all components were processed to paraffin and used to construct a single standard paraffin block. The muscles of mosquitofish and arteries of the spleen are positive controls for eosin staining, while other tissues are useful for assessing hematoxylin staining. The mosquitofish tissues also are excellent controls for the Masson trichrome stain and all mucin-related histochemical stains that we tested. The goblet cells of the intestine and skin stained strongly with Alcian blue, pH 2.5 (AB-2.5), mucicarmine, colloidal iron, periodic acid Schiff (PAS) or PAS-hematoxylin (PASH) and combination stains such as colloidal iron-PASH. Cell lines were not useful for evaluating histochemical stains except for PASH. The splenic stroma was a useful control for AB-2.5; however, eosin and mucin stains stained cell lines poorly, probably due to their rapid growth and associated loss of some differentiated characteristics such as production of mucins. Nevertheless, the cell lines were a critical control for immunohistochemical stains. Immunostaining of specific cell lines was consistent with the presence of markers, e.g., EGFr in DU145 cells. The cell lines expressed a wide range of markers, so they were useful controls for immunohistochemical staining including EGFr, HER2, E-cadherin, cytokeratins, Ki67, PCNA, estrogen receptor, progesterone receptor, CD3, CD20 and CD45, activated (cleaved) caspase 3 and Bcl-2. The cell lines also were a control for the TUNEL stain.     

Interspecific variation of body shape and sexual dimorphism in three coexisting species of the genus <Emphasis Type="Italic">Petrotilapia</Emphasis> (Teleostei: Cichlidae) from Lake Malawi

Differences in color patterns have been the most used feature in describing cichlid species belonging to genus Petrotilapia from Lake Malawi. In this study, we quantified morphological variation in body shape within and among three coexisting Petrotilapia species using landmark-based geometric morphometric methods. Statistic analyses revealed significant body shape differences among species but not between sexes. Post hoc multiple comparisons based on Mahalanobis distances revealed that P. nigra was significantly different from P. genalutea and Petrotilapia sp., whereas the latter two were not significantly different. The splines generated showed that the most pronounced variation was in the head region, in which P. nigra had a relatively longer and deeper head than the other two. The most clear-cut distinction was in gape length; P. genalutea had the longest gape, followed by Petrotilapia sp., whereas P. nigra had the shortest gape. Body depth was shallower in P. nigra than the others. When comparing sexes by their centroid size, ANOVA revealed that males were bigger than females. Therefore, we conclude that color is not the only feature that can distinguish these congeners. We discuss the observed sexual dimorphism in terms of sexual selection and relate morphological variation among species to feeding behavior, which may help explain their coexistence in nature.     

Trehalose Increases Freeze-Thaw Damage in Liposomes Containing Chloroplast Glycolipids

Chloroplast thylakoids contain three classes of glycolipids, monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), and sulfoquinovosyldiacylglycerol (SQDG). We have investigated the stability of large unilamellar vesicles made from egg phosphatidylcholine (EPC) and different chloroplast glycolipids during freezing to -18 degreesC, as a function of the presence of three sugars: glucose, sucrose, or trehalose. Contrary to the situation in thylakoids, where cryoprotection increases from glucose < sucrose < trehalose, liposomes containing 50% DGDG showed the opposite behavior. In fact, carboxyfluorescein leakage increased over the control values (freezing in the absence of sugar) in the presence of trehalose. This effect was not seen in vesicles made from pure EPC, or a mixture of EPC and MGDG, or EPC and SQDG. Liposomes made from mixtures of all three glycolipids, however, showed even more leakage in the presence of trehalose than liposomes containing only DGDG and EPC. Copyright 1998 Academic Press.     

Biosynthesis of phenylalanine,tyrosine, 3-(3-carboxyphenyl)alanine and 3-(3-carboxy-4-hydroxyphenyl)alanine in higher plants: Examples of the transformation possibilities for chorismic acid

¹⁴C-labelled shikimic acid and double labelled shikimic acid tritiated stereospecifically at C-6 are incorporated into 3-(3-carboxyphenyl)alanine, 3-(3-carboxyl-4-hydroxyphenyl)alanine, phenylalanine, and tyrosine in Resda lutea L., Reseda odoratta L., Iris x Hollandica cv. Prof. Blauw, and Iris x hollandica cv. Wedgwood. The experiments with ¹⁴C-labelled shikimic acid confirm that the aromatic carboxyl groups and rings in 3-(3-carboxyphenyl)-alanine and 3-(3-carboxy-4-hydroxyphenyl)alanine derive from the carboxyl group and ring in shikimic acid whereas the experiments with double labelled shikimic acid demonstrate that the pro-6S-hydrogen atom is retained and the pro-6R-hydrogen atom lost in the biosynthesis of 3-(3-carboxyphenyl)alanine, phenylalanine, and tyrosine in the plants used. ³H was located in the ortho-position in the aromatic rings of phenylalanine and tyrosine but in a position para to the alanine side chain of 3-(3-cabroxyphenyl)alanine. No ³H was found in 3-(3-carboxy-4-hydroxyphenyl)alanine. This supports a derivation of the last two compounds from chorismic acidvia isochorismic acid, isoprephenic acid, and 3′-carboxyphenylpyruvic acid and 3′-carboxy-4′-hydroxyphenylpyruvic acid. The ³H/¹⁴ C ratio in 3-(3-carboxyphenyl)alanine was found higher than in the precursor used. This isotope effect must operate by competition between the pathways from isoprephenic acid to 3′-carboxyphenylpyruvic acid and to 3′-carboxy-4′-hydroxyphenylpyruvic acid. The proposed biosynthetic pathways for the two carboxy-substituted amino acids are in agreement with their distribution patterns in the plant kingdom and suggest that they may derive from minor changes of enzymes involved in the general pathways of aromatic biosynthesis.