Isolation of rsp-1, a novel cDNA capable of suppressing v-Ras transformation.

Using an expression cloning assay, we have isolated a novel cDNA, referred to as rsp-1, which suppresses the v-Ras-transformed phenotype. When introduced into NIH 3T3 fibroblasts under the control of a metallothionein promoter, rsp-1 confers resistance to v-Ras, but not to v-Mos or v-Src, and inhibits growth of the cells. The rsp-1 cDNA contains a 831-bp open reading frame encoding a 277-amino-acid leucine-rich protein. The rsp-1 cDNA exhibits no significant homology to sequences in the DNA data bases. However, searches of the protein data bases revealed that it contains a series of leucine-based repeats which are homologous to the leucine repeats found in the regulatory region of the yeast adenylyl cyclase. rsp-1 specific RNA is detectable in a wide variety of cell lines and tissues, and the gene is conserved among eukaryotic species. These data suggest that rsp-1 plays a role in Ras signal transduction.     

Fractionation techniques in a hydro-organic environment. II. Acryloyl-morpholine polymers as a matrix for electrophoresis in hydro-organic solvents

The properties of gels prepared either from acryloyl-morpholine (ACM) or from its mixtures with acrylamide and crosslinked either with bisacrylylpiperazine or with methylenebisacrylamide have been described. ACM-containing gels are compatible with organic solvents. If polymerized in water and dried, they are able to reswell, e.g., in dimethyl sulfoxide or dimethylformamide. If polymerized in presence of dimethylformamide, they form perfectly clear gels, whose mechanical properties are by far superior than those of similar plain polyacrylamide formulations.     

Otto Kuntze,botanist. IV. Recent addition of specimens to the New York Botanical Garden Herbarium with other notes on Kuntze

A small set of plant specimens from the original Kuntze herbarium have been returned to the New York Botanical Garden (NY) by the Charleston Museum (CHARL).     

Otto Kuntze,botanist. III. Type specimens of fern,gymnosperm and monocotyledon taxa from his Revisio Generum Plantarum

Type specimens of fern, gymnosperm and monocotyledon taxa described as new by Otto Kuntze in hisRevisio Generum Plantarum Vols. I and II (1891) and Vol. III (1898) known to be in the herbarium of the New York Botanical Garden (NY) are listed. Specimens for all of the new taxa were not found at NY.     

Turning a green alga red: engineering astaxanthin biosynthesis by intragenic pseudogene revival in Chlamydomonas reinhardtii

The green alga Chlamydomonas reinhardtii does not synthesize high‐value ketocarotenoids like canthaxanthin and astaxanthin; however, a β‐carotene ketolase (CrBKT) can be found in its genome. CrBKT is poorly expressed, contains a long C‐terminal extension not found in homologues and likely represents a pseudogene in this alga. Here, we used synthetic redesign of this gene to enable its constitutive overexpression from the nuclear genome of C. reinhardtii. Overexpression of the optimized CrBKT extended native carotenoid biosynthesis to generate ketocarotenoids in the algal host causing noticeable changes the green algal colour to reddish‐brown. We found that up to 50% of native carotenoids could be converted into astaxanthin and more than 70% into other ketocarotenoids by robust CrBKT overexpression. Modification of the carotenoid metabolism did not impair growth or biomass productivity of C. reinhardtii, even at high light intensities. Under different growth conditions, the best performing CrBKT overexpression strain was found to reach ketocarotenoid productivities up to 4.3 mg/L/day. Astaxanthin productivity in engineered C. reinhardtii shown here might be competitive with that reported for Haematococcus lacustris (formerly pluvialis) which is currently the main organism cultivated for industrial astaxanthin production. In addition, the extractability and bio‐accessibility of these pigments were much higher in cell wall‐deficient C. reinhardtii than the resting cysts of H. lacustris. Engineered C. reinhardtii strains could thus be a promising alternative to natural astaxanthin producing algal strains and may open the possibility of other tailor‐made pigments from this host.     

Virulence of infecting Helicobacter pyloristrains and intensity of mononuclear cell infiltration are associated with levels of DNA hypermethylation in gastric mucosae

DNA methylation changes are known to occur in gastric cancers and in premalignant lesions of the gastric mucosae. In order to examine variables associated with methylation levels, we quantitatively evaluated DNA methylation in tumors, non-tumor gastric mucosae, and in gastric biopsies at promoters of 5 genes with methylation alterations that discriminate gastric cancers from non-tumor epithelia (EN1, PCDH10, RSPO2, ZIC1, and ZNF610). Among Colombian subjects at high and low risk for gastric cancer, biopsies from subjects from the high-risk region had significantly higher levels of methylation at these 5 genes than samples from subjects in the low risk region (p ≤ 0.003). When results were stratified by Helicobacter pylori infection status, infection with a cagA positive, vacA s1m1 strain was significantly associated with highest methylation levels, compared with other strains (p = 0.024 to 0.001). More severe gastric inflammation and more advanced precancerous lesions were also associated with higher levels of DNA methylation (p ≤ 0.001). In a multivariate model, location of residence of the subject and the presence of cagA and vacA s1m1 in the H. pylori strain were independent variables associated with higher methylation in all 5 genes. High levels of mononuclear cell infiltration were significantly related to methylation in PCDH10, RSPO2, and ZIC1 genes. These results indicate that for these genes, levels of methylation in precancerous lesions are related to H. pylori virulence, geographic region and measures of chronic inflammation. These genes seem predisposed to sustain significant quantitative changes in DNA methylation at early stages of the gastric precancerous process.     

Lipophyllic antioxidants from Iryanthera juruensis fruits

The phytochemical investigation of the hexane extract of Iryanthera juruensis (Myristicaceae) fruits led to the isolation of two tocotrienols and four lignans which exhibited antioxidant activity towards beta-carotene on TLC autographic assay. Two inactive quinones and three omega-arylalkanoic acids were also isolated. The isolates were investigated for their redox properties using cyclic voltammetry. The structure elucidation of the new compounds (one tocotrienol. one quinone and three omega-arylalkanoic acids) was based on analysis of spectroscopic data.