Nucleotide sequences of four pathogen-induced alfalfa peroxidase-encoding cDNAs

We constructed an alfalfa cDNA library from mRNA extracted from leaves after infection with Pseudomonas syringae (incompatible interaction). Screening with oligodeoxyribonucleotides designed from regions conserved in all known peroxidases allowed the isolation of four cDNAs (MsprxlA, 1B, 1C and 2). Sequence analysis revealed the presence of open reading frames of 351, 355, 358 and 323 amino acids, respectively, with the characteristic consensus sequences of plant peroxidases. Sequence comparison showed that the Msprx2 product is significantly different from the others and, particularly, lacks a C-terminal propeptide which might be required for vacuolar targeting.     

The action of cyclic somatostatin on hypoglycemia due to prolonged fasting in normal animals]

The authors have examined the action of cyclic Somatostatin on blood glucose levels in normal rats and in rats starved for 36 and 50 hours. The infusion of 0,235 gamma/min. of Somatostatin for thirty minutes in the normals induced a slight increase in blood glucose levels that was statistically non significative. Under the same condition, the cyclic Somatostatin increased, in a statistically significant way, the levels of plasma glucose in both starved groups of rats.     

Biochemical investigation to the reliability of the histochemical demonstration of microsomal arylsulphatase activity in cryostat sections

Summary Polyacrylamide gel-electrophoresis was performed with an extract from cultivated skin fibroblasts. Arylsulphatase activity is measured and visualised using the biochemical substrate dehydroepiandrosterone sulphate and the histochemical substrate 6-bromo-2-naphthyl sulphate respectively. The histochemical substrate was hydrolysed at Rf=0.49 and 0.58 while the biochemical substrate was hydrolysed only at 0.49. We conclude that two different microsomal arylsulphatases exist: a sulphatase able to hydrolyse steroid sulphatases (Rf=0.49) and one unable to hydrolyse steroid sulphatases (Rf=0.58). In consequence it is recommended to carry out an electrophoresis experiment after the histochemical investigation, in order to discriminate between these two types of sulphatase.     

Paratope- and framework-related cross-reactive idiotopes on anti-acetylcholine receptor antibodies

Cross-reactive idiotopes are a possible target for therapeutical interventions in autoimmune diseases. To investigate their role in the pathogenesis of experimental autoimmune myasthenia gravis (EAMG) we analyzed the Id of rat anti-AChR mAb 6, 35, 61, 65 and a control myeloma protein IR27. Anti-Id 6, 35, 61, 65 bound in a direct binding assay with various affinity to all rat anti-AChR mAb that were tested. Anti-Id IR27 recognized none of the anti-AChR mAb. The specificity of these crossreactions was confirmed by inhibition studies with anti-AChR mAb and two control rat myeloma proteins (IR27 and IR241). In addition, the Id expression on mAb D6, a mouse anti-human AChR mAb was recognized by anti-Id 6, 35, and 65. Anti-Id, except anti-Id IR27, bound to affinity purified IgG from the sera of rats with EAMG, but not to preimmune Lewis IgG. These results suggest extensive sharing of idiotopes among anti-AChR mAb, which are also present in EAMG serum. Anti-AChR mAb against the main immunogenic region (6, 35, 65) from different rat strains, shared at least one paratope-related cross-reactive idiotopes. In the view of the fact that anti-main immunogenic region antibodies might form a predominant fraction of the polyclonal response against AChR, it is conceivable that an anti-Id recognizing these antibodies could have therapeutical applications as for example a selective immune absorbent or in immunotoxin therapy.     

Lack of AKR ecotropic provirus amplification in AKR leukemic thymuses.

A DNA fragment from the 3' region of a molecularly cloned AKR ecotropic provirus was identified to be specific for the AKR ecotropic murine leukemia virus (MuLV). This selected DNA fragment was used to analyze the integrated MuLV proviruses in normal and leukemic tissue DNAs of AKR mice. In comparison with a DNA fragment from the 5' region of the cloned AKR genome or one representing the entire genome, this selected probe hybridized to only a few MuLV proviruses. By comparing transformed and nontransformed tissue DNAs, it appeared that no amplification of proviral sequences related to the AKR ecotropic MuLV had occurred in thymomas of AKR mice during the development of leukemia in these animals. Analysis of the AKR ecotropic MuLV proviruses revealed a significant degree of polymorphism for these sequences among individuals in the AKR/J strain of mouse.     

Can fossil fuel energy be recovered and used without any CO2 emissions to the atmosphere?

Reviews in Environmental Science and Bio/Technology - The world’s energy system is still dominated by fossil fuels. While there is a rapid reduction in the cost of renewable energy and the...     

Immunohistochemical localization of caffeine in young Camellia sinensis (L.) O. Kuntze (tea) leaves

The anatomical localization of caffeine within young Camellia sinensis leaves was investigated using immunohistochemical methods and confocal scanning laser microscopy. Preliminary fixation experiments were conducted with young C. sinensis leaves to determine which fixation procedure retained caffeine the best as determined by high-performance liquid chromatography analysis. High pressure freezing, freeze substitution, and embedding in resin was deemed the best protocol as it retained most of the caffeine and allowed for the samples to be sectioned with ease. Immunohistochemical localization with primary anti-caffeine antibodies and conjugated secondary antibodies on leaf sections proved at the tissue level that caffeine was localized and accumulated within vascular bundles, mainly the precursor phloem. With the use of a pressure bomb, xylem sap was collected using a micro syringe. The xylem sap was analyzed by thin-layer chromatography and the presence of caffeine was determined. We hypothesize that caffeine is synthesized in the chloroplasts of photosynthetic cells and transported to vascular bundles where it acts as a chemical defense against various pathogens and predators. Complex formation of caffeine with chlorogenic acid is also discussed as this may also help explain caffeine’s localization.