Influence of atorvastatin and carboxymethylated glucan on the serum lipoprotein profile and MMP activity of mice with lipemia induced by poloxamer 407

The effects of atorvastatin and carboxymethylated β-glucan (CMG) on the lipoprotein-cholesterol (LP-C) and lipoprotein-triglyceride (LP-TG) fractions and subfractions at the early stage of murine hyperlipidemia, and its pleiotropic anti-inflammatory effects, were studied. Atorvastatin and CMG were administered in ICR male mice with acute lipemia induced with a single injection of poloxamer 407 (P-407). A novel small-angle X-ray scattering method for the determination of fractional and subfractional composition of LP-C and LP-TG was used. In P-407-treated animals, there was a drastic increase of total cholesterol and especially TG. Atorvastatin decreased both the total cholesterol and TG, but not to control levels. CMG primarily decreased TG and was not as potent as atorvastatin. P-407 increased atherogenic LDL-C (IDL-C and LDL(1-3)-C subfractions) and very low-density lipoprotein-C (VLDL-C) (VLDL(1-2)-C and VLDL(3-5)-C subfractions) fractions, with an increase of the total anti-atherogenic HDL-C fraction (HDL(2)-C subfraction). Atorvastatin treatment of lipemia was followed by a decrease in the total LP-C, total LDL-C (LDL(1-3)-C subfraction), and the LDL(1-3)-TG subfraction. Additionally, atorvastatin treatment resulted in an increase in the serum matrix metalloproteases activity both in control and P-407-treated mice. In general, high-dose atorvastatin therapy exerts its lipid-lowering and pleiotropic effects in the early stages of acute lipemia induced in mice by treatment with P-407.     

Inhibitors of anthrax lethal factor

An inhibitor of anthrax lethal toxin mediated cell death (1) was identified by a medium throughput cell-based screen. This compound was determined to specifically inhibit anthrax lethal factor (LF), and subsequent SAR studies produced an even more potent inhibitor (4). Mechanistic studies identified these agents as uncompetitive inhibitors of LF with Ki values of 3.0 and 1.7 microM, respectively, with good cell potency and low cytotoxicity.     

Two Arabidopsis homologs of the animal trithorax genes: a new structural domain is a signature feature of the trithorax gene family.

Two Arabidopsis genes have been characterized as first examples of plant genes homologous to the animal trithorax genes. The Arabidopsis genes are highly similar but display different tissue and development expression patterns. One of them was ubiquitously expressed, with highest levels registered in young seedlings. The other gene was less active in all tested tissues, was not expressed in mature leaves but was highly expressed in roots. A new structural motif common to all TRX-related proteins has been identified. This new architectural element was found only in genes of multicellular species and is present in all genes belonging to the trithorax family. Along with the SET domain and the PHD fingers, this new element is a signature feature for the trithorax gene family.     

Utilization Modes of Inorganic Carbon for Photosynthesis in Various Species of Chlorella

Rates of CO₂ and HCC₃^– fixation in cells of various Chlorellaspecies in suspension were compared from the amounts of ¹⁴Cfixed during the 5 s after the injection of a solution containingonly ¹⁴CO₂ or H¹⁴CO₃^–. Results indicated that irrespectiveof the CO₂ concentration during growth, Chlorella vulgaris 11h and C. miniata mainly utilized CO₂, whereas C. vulgaris C-3,C. sp. K. and C. ellipsoidea took up HCO₃^– in additionto CO₂. Cells of C. pyrenoidosa that had been grown with 1.5%CO₂ (high-CO₂ cells) mainly utilized CO₂, whereas those grownwith air (low-CO₂ cells) utilized HCO₃^– in addition toCO₂. Cells that utilized HCO₃^– had carbonic anhydrase(CA) on their surfaces. The effects of Diamox and CA on the rates of CO₂ and HCO₃^–fixation are in accord with the inference that HCO₃^– wasutilized after conversion to CO₂ via the CA located on the cellsurface. CA was found in both the soluble and insoluble fractions;the CA on the cell surface was insoluble. Independent of the modes of utilization, the apparent K_m (NaHCO₃)for photosynthesis was much lower in low-CO₂ cells than in high-CO₂ones. The fact that the CA in the soluble fraction in C. vulgarisC-3 was closely correlated with the K_m(NaHCO₃) indicates thatsoluble CA lowers the K_m. ¹ Dedicated to the late Professor Joji Ashida, one of the foundersand first president of the Japanese Society of Plant Physiologists. ⁴ On leave from Research and Production Laboratory of Algology,Bulgarian Academy of Sciences, Sofia. (Received September 14, 1982; Accepted March 1, 1983)     

Trout sperm chromatin. II. Ultrastructural aspects after salt dissociation of proteins

The ultrastructural organization of the trout sperm nucleus was studied in ultrathin sections and spread preparations after partial decondensation of the nucleus with increasing NaCl concentrations. The obtained results suggest that the organization of the trout sperm chromatin is much more complex than a pure nucleoprotamine. Three types of complexes were observed. The first one results from the association of DNA with protamines. This complex appears as a fibrous network when partially decondensed nuclei are digested with DNase I indicating that at least a part of DNA remains protected by protamines and favours models accepting a colinear alignment of the latter on the DNA molecules. The second type of structures represent the DNA-protamine fibers compacted into dense clumps which appear as separate compaction units seen upon partial decondensation of the sperm nucleus. A third type are complexes of the ring-shaped granular bodies tightly associated with DNA and resisting high salt-urea and detergent treatment.     

Temperature effect on bacterial azo bond reduction kinetics: an Arrhenius plot analysis

Studied was the effect of temperature in the range 12–46 °C on the rate of bacterial decolorization of the mono-azo dye Acid Orange 7 by Alcaligenes faecalis 6132 and Rhodococcus erythropolis 24. With both strains the raise of temperature led to a corresponding raise of decolorization rate better manifested by R. erythropolis. The analysis of the Arrhenius plot revealed a break near the middle of the temperature range. The regression analysis showed practically complete identity of the observed break point temperatures (T _BP): 20.7 °C for Alc. faecalis and 20.8 °C for R. erythropolis. The values of the activation energy of the decolorization reaction (E _a) were found to depend on both the organism and the temperature range. In the range below T _BP the estimated values of E _a were 138 ± 7 kJ mol⁻¹ for Alc. faecalis and 160 ± 8 kJ mol⁻¹ for R. erythropolis. In the range above T _BP they were 54.2 ± 1.8 kJ mol⁻¹ for Alc. faecalis and 37.6 ± 4.1 kJ mol⁻¹ for R. erythropolis. Discussed are the possible reasons for the observed abrupt change of the activation energy.     

Testosterone stimulates the expression of a social color signal in Yarrow's Spiny Lizard, Sceloporus jarrovii

The sex steroid testosterone has been shown to regulate the development of male-specific coloration in many organisms that exhibit sexual dichromatism, but the role of testosterone is less certain for species in which both sexes express bright coloration. Lizards in the genus Sceloporus possess bright blue patches on their throats and abdomens. These patches, which are used in social signaling, are often regulated by testosterone and are consequently expressed only in males of most species. However, Yarrow's Spiny Lizard (Sceloporus jarrovii, Cope 1875) exhibits a derived condition in which both sexes express bright blue ventral patches despite dramatic sexual differences in circulating testosterone levels throughout postnatal ontogeny. In this study, we used surgical castration and hormone replacement in juvenile males to test the hypothesis that testosterone stimulates the expression of blue ventral coloration in S. jarrovii. In two separate experiments conducted in captivity and the natural field environment, we found that surgical castration decreased the hue and saturation while increasing the brightness of blue throat and abdominal patches. Castration also decreased the amount of black pigment bordering the blue throat patch. Treatment of castrated males with exogenous testosterone restored all aspects of ventral coloration to values similar to those of intact control males. Early organizational effects of testosterone during prenatal development may lead to the expression of blue coloration in both sexes, but the results of our present experiments indicate that subsequent effects of testosterone during sexual maturation further enhance the coloration of males.     

Putative subunits of the maize origin of replication recognition complex ZmORC1-ZmORC5

The finding in animal species of complexes homologous to the products of six Saccharomyces cerevisiae genes, origin of replication recognition complex (ORC), has suggested that ORC-related mechanisms have been conserved in all eukaryotes. In plants, however, the only cloned putative homologs of ORC subunits are the Arabidopsis ORC2 and the rice ORC1. Homologs of other subunits of plant origin have not been cloned and characterized. A striking observation was the absence from the Arabidopsis genome of an obvious candidate gene-homolog of ORC4. This fact raised compelling questions of whether plants, in general, and Arabidopsis, in particular, may have lost the ORC4 gene, whether ORC-homologous subunits function within a complex in plants, whether an ORC complex may form and function without an ORC4 subunit, whether a functional (but not sequence) protein homolog may have taken up the role of ORC4 in Arabidopsis, and whether lack of ORC4 is a plant feature, in general. Here, we report the first cloned and molecularly characterized five genes coding for the maize putative homologs of ORC subunits ZmORC1, ZmORC2, ZmORC3, ZmORC4 and ZmORC5. Their expression profiles in tissues with different cell-dividing activities are compatible with a role in DNA replication. Based on the potential of ORC-homologous maize proteins to bind each other in yeast, we propose a model for their possible assembly within a maize ORC. The isolation and molecular characterization of an ORC4-homologous gene from maize argues that, in its evolution, Arabidopsis may have lost the homologous ORC4 gene.     

Structural domains and matrix attachment regions along colinear chromosomal segments of maize and sorghum

Although a gene's location can greatly influence its expression, genome sequencing has shown that orthologous genes may exist in very different environments in the genomes of closely related species. Four genes in the maize alcohol dehydrogenase (adh1) region represent solitary genes dispersed among large repetitive blocks, whereas the orthologous genes in sorghum are located in a different setting surrounded by low-copy-number DNAs. A specific class of DNA sequences, matrix attachment regions (MARs), was found to be in comparable positions in the two species, often flanking individual genes. If these MARs define structural domains, then the orthologous genes in maize and sorghum should experience similar chromatin environments. In addition, MARs were divided into two groups, based on the competitive affinity of their association with the matrix. The "durable" MARs retained matrix associations at the highest concentrations of competitor DNA. Most of the durable MARs mapped outside genes, defining the borders of putative chromatin loops. The "unstable" MARs lost their association with the matrix under similar competitor conditions and mapped mainly within introns. These results suggest that MARs possess both domain-defining and regulatory roles. Miniature inverted repeat transposable elements (MITEs) often were found on the same fragments as the MARs. Our studies showed that many MITEs can bind to isolated nuclear matrices, suggesting that MITEs may function as MARs in vivo.