Platinum (II) complex with cyclometalating 2-phenylpyridine ligand showing high cytotoxicity against cisplatin-resistant cell

A platinum (II) mononuclear complex with two kinds of 2-phenylpyridine which coordinate as cyclometalated and non-chelated ligands shows high cytotoxicity against cisplatin-resistant mouse sarcoma 180 cell in comparison with its related complexes.     

Aplysiallene, a new bromoallene as an Na, K-ATPase inhibitor from the sea hare, Aplysia kurodai

A new bromoallene metabolite, named aplysiallene, was isolated from the Japanese sea hare, Aplysia kurodai, as an Na, K-ATPase inhibitor. Its structure was elucidated by spectroscopic methods. The known metabolites, laurinterol and debromolaurinterol, isolated from this animal were also evaluated for their Na, K-ATPase inhibitory activity.     

Genetic similarity and relationships of DNA fingerprints with performance and with heterosis in Japanese quail lines from two origins and under reciprocal recurrent or within-line selection for early egg production

DNA fingerprints of Japanese quail male and female pure line breeders were obtained with probes 33.6, 33.15, and R18.1 and they yielded a total of 59 scoreable bands. Bandsharing (0 < BS < 1) was calculated within and between six quail lines of two origins, and under reciprocal recurrent (AA and BB), within-line (DD and EE) or no (PP and FF) selection. Twenty one pair types were compared. BS was 0.30 higher within line than between lines. BS with the control line was smaller for reciprocal recurrent selection lines than for lines under individual selection. Bandsharing between the two reciprocal recurrent selection lines was 0.19 lower than between lines under individual selection. These results indicate that the two selection methods had different effects on the genetic constitution of the lines, in agreement with previous observations made from the analysis of biochemical polymorphisms with the same set of birds. Egg production and weight traits of pure and crossbred progeny from fingerprinted quail were obtained and compared, and a linear relationship with the measure of bandsharing was estimated. No significant regression coefficient of performance on BS was found over all progeny genetic types. Heterosis from individual matings could also be estimated under the two selection methods since the same birds were parents of both pure and crossbred performance-tested quail. The association of heterosis with the difference between BS of parents of the purebreds and BS of parents of their half-sib crossbreds was favourable and significant for early production traits in lines DD and EE, but no relationship was found in lines AA and BB. These results indicate that the high level of heterosis obtained through reciprocal recurrent selection, and the heterosis observed under within-line selection may have, partly at least, a different genetic determinism. Therefore, the relationship of heterosis with BS may also depend on the past history of selection in the lines.     

Genetic evaluation of peroxisomal and cytosolic acetoacetyl-CoA thiolase isozymes in n-alkane-assimilating diploid yeast, Candida tropicalis

The n-alkane-assimilating diploid yeast, Candida tropicalis, possesses two acetoacetyl-CoA thiolase (Thiolase I) isozymes encoded by one allele: peroxisomal and cytosolic Thiolase Is encoded by both CT-T1A and CT-T1B. To clarify the function of peroxisomal and cytosolic. Thiolase Is, the site-directed mutation leading Thiolase I ΔC6 without a putative C-terminal peroxisomal targeting signal was introduced on CT-T1A locus in the ct-t1bΔ-null mutant. The C-terminus-truncated Thiolase I was active and solely present in the cytosol. Although the ct-t1aΔ/t1bΔ-null mutants showed mevalonate auxotrophy, the mutants having the C-terminus-truncated Thiolase I did not require mevalonate for growth, as did the strains having cytosolic Thiolase I. These results demonstrated that the presence of Thiolase I in the cytoplasm is indispensable for the sterol synthesis in this yeast. It is of greater interest that peroxisomal and cytosolic Thiolase I isozymes, products of the same genes, play different roles in the respective compartments, although further investigations will be necessary to analyze how to be sorted into peroxisomes and the cytosol.     

Purification and characterization of extracellular laccase fromPleurotus ostreatus

Laccase (EC 1.10.3.2) from the culture filtrate of a strain of white rot basidiomycetePleurotus ostreatus was purified using DEAE-Toyopearl 650M and butyl-Toyopearl 650M column chromatographies and Superdex 75 HR 10/30 fast protein liquid chromatography. Molecular weight of the purified laccase was about 55,000, and the isoelectric point was 3.0. The optimum pH for enzyme activity was 6.5, and the optimum temperature was 50°C. This enzyme contained 7.4% sugar and two copper atoms per molecule. The substrate specificity was similar to those of other fungal laccases. Comparison of the N-terminal amino acid sequence of theP. ostreatus laccase with those fromPleurotus ostreatus Florida,Coriolus hirsutus, Phlebia radiata, basidiomycete PM1 (CECT 2971),Trametes villosa, Pycnoporus cinnabarinus, Ceriporiopsis subvermispora, andAgaricus bisporus showed 95, 65, 60, 55, 55, 55, 50, and 35% similarity, respectively, in the first 20 residues. No similarity in this region was detected with laccases fromNeurospora crassa, Aspergillus nidulans, andCryptococcus neoformans.     

Differences in the induction of thymidine kinase isozymes in estrogen-treated immature and adult rats

Thymidine kinase activity in immature and castrated adult rat uterus has been examined in respose to estrogen treatment. Following estrogen administration. it was found that immature uterine thymidine kinase activity was increased 30-fold after 24 h, but almost no effect was produced on castrated or non-castrated adult uterus. Uterine thymidine kinase activity was separated into three peaks (peak 1, 2 and 3) by means of DEAE-cellulose column chromatography. In response to estrogen, the thymidine kinase isozymes differed in adult and immature uteri. In immature uteri, marked and selective increase of the activity was found in peak I, whereas in adult only a slight increase in peak 2 activity was observed. The thymidine kinase activity in peak 1 and peak 2 were found to have different enzymatic properties and molecular weight, as determined by gel filtration of 125 000 for peak 1 and 100 000 for peak 2.From these results, it is suggested that estrogen induces specific thymidine kinase isozyme in immature uterus and that the isozyme may be involved in DNA synthesis. Such a induction mechanism seems to be lost during the development.     

A new serine protease which preferentially recognizes p-guanidino-L-phenylalanyl residue in ascitic plasma from Ehrlich ascites tumor-bearing mice

A new enzyme which hydrolyzes anilide substrates of p-guanidino-L-phenylalanine in preference to those of arginine was found in the ascitic plasma from Ehrlich ascites tumor-bearing mice. The activity of this enzyme on N alpha-benzyloxycarbonyl-p-guanidino-L-phenylalanine p-nitroanilide was strongly inhibited by diisopropyl fluorophosphate and phenylmethanesulfonyl fluoride but not by sulfhydryl-reactive reagents and metal chelating agents. Peptide substrates containing p-guanidino-L-phenylalanine were hydrolyzed by this enzyme much faster than those containing arginine. These results suggest that this enzyme is a different type of serine protease from trypsin and thrombin. This enzyme was also found in the human gastric and colon cancer cells and their surrounding ascitic plasmas.