Verrucosamide,a Cytotoxic 1,4-Thiazepane-Containing Thiodepsipeptide from a Marine-Derived Actinomycete

A new cytotoxic thiodepsipeptide, verrucosamide (1), was isolated along with the known, related cyclic peptide thiocoraline, from the extract of a marine-derived actinomycete, a Verrucosispora sp., our strain CNX-026. The new peptide, which is composed of two rare seven-membered 1,4-thiazepane rings, was elucidated by a combination of spectral methods and the absolute configuration was determined by a single X-ray diffraction study. Verrucosamide (1) showed moderate cytotoxicity and selectivity in the NCI 60 cell line bioassay. The most susceptible cell lines were MDA-MB-468 breast carcinoma with an LD₅₀ of 1.26 µM, and COLO 205 colon adenocarcinoma with an LD₅₀ of 1.4 µM. Also isolated along with verrucosamide were three small 3-hydroxy(alkoxy)-quinaldic acid derivatives that appear to be products of the same biosynthetic pathway.     

Flow cytometric assessment of ethylene glycol monoethyl ether on spermatogenesis in rats

The effects of ethylene glycol monoethyl ether (EGEE) on testicular cell populations in rats were investigated by a flow cytometric method. Rats were administered by gavage with EGEE at the various doses of 0 (saline alone), 100, 200, 400, and 800 mg/kg body weight/day for 4 weeks. The treatment of EGEE caused decreases in the weight of testis and epididymis and in the number of testicular cells. Histopathologically, exfoliation of germ cells into the tubular lumen was observed at the doses of above 200 mg/kg. The treatment of EGEE at the dose of 400 mg/kg caused moderate testicular degeneration. A significant depletion of haploid cells and a disproportionate ratio of diploid and tetraploid cells were observed as determined by flow cytometric analysis. These results indicate that the toxic effect of EGEE on the male reproductive system may be strongly associated with the disproportion of testicular germ cells.     

Effects of diosmin, a flavonoid glycoside in citrus fruits, on P-glycoprotein-mediated drug efflux in human intestinal Caco-2 cells

The effects of citrus flavonoids on P-glycoprotein (P-gp)-mediated drug efflux were examined in human intestinal Caco-2 cells. The cellular accumulation of rhodamine-123 was measured using 10 citrus flavonoids for preliminary screening. Among the flavonoids tested, diosmin significantly increased the accumulation of rhodamine-123 in Caco-2 cells. In the bidirectional transport of digoxin, diosmin increased the apical-to-basal (A-to-B) transport but decreased the basal-to-apical (B-to-A) transport in both concentration- and time-dependent manners. The digoxin transport ratio (B-A/A-B) was estimated to be 2.3 at a concentration of 50 microM of diosmin, which was significantly lower than the 15.2 found in the control. The apparent Ki values for P(app,A-B) and P(app,B-A) were 16.1 and 5.7 microM, respectively. These results demonstrated that diosmin effectively inhibited the P-gp-mediated efflux in Caco-2 cells. Diosmin is one of the main components in citrus fruits, and the intake of food supplements containing this compound may potentially increase the absorption of drugs able to act as P-gp substrates. The clinical relevance of this interaction should be further evaluated using in vivo experiments.     

A simplified one-step nuclear transfer procedure alters the gene expression patterns and developmental potential of cloned porcine embryos

Various somatic cell nuclear transfer (SCNT) techniques for mammalian species have been developed to adjust species-specific procedures to oocyte-associated differences among species. Species-specific SCNT protocols may result in different expression levels of developmentally important genes that may affect embryonic development and pregnancy. In the present study, porcine oocytes were treated with demecolcine that facilitated enucleation with protruding genetic material. Enucleation and donor cell injection were performed either simultaneously with a single pipette (simplified one-step SCNT; SONT) or separately with different pipettes (conventional two-step SCNT; CTNT) as the control procedure. After blastocysts from both groups were cultured in vitro, the expression levels of developmentally important genes (OCT4, NANOG, EOMES, CDX2, GLUT-1, PolyA, and HSP70) were analyzed by real-time quantitative polymerase chain reaction. Both the developmental rate according to blastocyst stage as well as the expression levels CDX2, EOMES, and HSP70 were elevated with SONT compared to CTNT. The genes with elevated expression are known to influence trophectoderm formation and heat stress-induced arrest. These results showed that our SONT technique improved the development of SCNT porcine embryos, and increased the expression of genes that are important for placental formation and stress-induced arrest.     

Thermal and mechanical properties of modified CaCO3 filled poly (ethylene terephthalate) nanocomposites

Poly(ethylene terephthalate) (PET)/CaCO₃ and PET/modified-CaCO₃ (m-CaCO₃) nanocomposites were prepared by melt blending. The morphology indicated that m-CaCO₃ produced by reacting sodium oxalate and calcium chloride, was well dispersed in PET matrix and showed good interfacial interaction with PET compared to CaCO₃. No significant differences in the thermal properties such as, glass transition, melting and degradation temperatures, of the nanocomposites were observed. The thermal shrinkage of PET at 120 °C was 10.8 %, while those of PET/CaCO₃ and PET/m-CaCO₃ nanocomposites were 2.9–5.2 % and 1.2–2.8 %, respectively depending on filler content. The tensile strength of PET/CaCO₃ nanocomposite decreased with CaCO₃ loading, whereas that of PET/m-CaCO₃ nanocomposites at 0.5 wt% loading showed a 17 % improvement as compared to neat PET. The storage modulus at 120 °C increased from 1660 MPa for PET to 2350 MPa for PET/CaCO₃ nanocomposite at 3 wt% loading, and 3230 MPa for PET/m-CaCO₃ nanocomposite at 1 wt% loading.     

Lethal Effects of Pulsed High-Voltage Discharge on Marine Plankton and Escherichia coli

Ballast seawater is considered globally as a major vector for invasions of non-indigenous organisms. Several technologies have been tested for their ability to remove organisms from ballast water. In the present study, we constructed a novel pulsed high-voltage discharge (PHVD) system that could operate in either high current mode with several hundred amperes or shockwave generating mode with relatively lower current in seawater. In laboratory-scale experiments, the PHVD system with shockwave-generating mode was found to be more effective in killing zooplankton (1.9- to 4.0-fold) and phytoplankton (3.3-fold) than high current mode at discharge with 300–500 pulses at 7.1 kV. Further experiments were carried out at different voltages and pulse-numbers to examine effects of the shockwave-generating PHVD system on viabilities of one zooplankton larva, two phytoplankton species, and an indicator bacterium suspended in seawater in a static chamber. For zooplankton, live cells were not detected at discharge with 400 pulses at 13 kV. For phytoplankton, the initial live cells of a dinoflagellate was decreased by 77?±?0.5%, and the initial chl a concentration of a diatom was decreased by 76?±?6% at discharge with 700 pulses at 13 kV. For an indicator bacterium Escherichia coli, live cells were not detected at discharges with 200 or 700 pulses at 13 kV. Measurements of ATP content of organisms showed congruent results with those obtained by the above methods, suggesting it may be a rapid method for evaluating treatment efficiency. Though further scale-up studies are necessary, these results suggest that the PHVD system have a high potential for applying to ballast seawater treatment.     

A comparative study on the rumen microbial populations,hydrolytic enzyme activities and dry matter degradability between different species of ruminant

A comparative study among Korean native cow (Hanwoo), Holstein dairy cow, Korean native goat and crossbred sheep on the population and marker concentration of ruminal microbes, the activities of carboxymethylcellulase (CMCase), xylanase and amylase, and in situ dry matter (DM) degradability were conducted. Twelve ruminally cannulated animals, three of each species, were used. Animals were fed the same diet containing 40% formula feed and 60% rice straw at the level of 2.5% of body weight. Total viable microbial populations in the rumen fluid were significantly (P < 0.01) greater for bacteria and fungi in goat than those of Holstein. The protozoan population among ruminant species was the reverse from that of bacteria. The concentrations of 2,6‐diaminopimelic acid and chitin as markers for bacteria and fungi in the rumen fluid, respectively, were highest in goat, which is in accordance with the above population data. The concentration of aminoethylphosphonic acid as marker of protozoa was highest in Hanwoo and lowest in sheep (P < 0.01). Goat had the highest (P < 0.01) activities of all the enzymes investigated among ruminants. In situ effective degradation of the DM of rice straw was approximately 19% higher in the rumen of goat compared with other animals.     

Pterocarpan profiles for soybean leaves at different growth stages and investigation of their glycosidase inhibitions

Soybean leaves are eaten as seasonal edible greens in Korea. Analysis of the ethyl acetate extract of these leaves showed that it exhibited potent and selective neuraminidase inhibition, which began at the R3 stage and peaked at R7. Ten pterocarpans, including the new 6a-hydroxypterocarpan 10, were isolated from soybean leaves and their inhibition activities tested against a range of glycosidases. The relationship between structure and enzyme inhibition was investigated: 6a-hydroxypterocarpans exhibited much higher inhibition against neuraminidase (IC(50) = 2.4-89.4 μM) than α-glucosidase (IC(50) = 90.4-?>100 μM). Glyceollin VII (7) displayed 40-fold greater activity (IC(50) = 2.4 μM) against neuraminidase than α-glucosidase (IC(50) = 90.4 μM). On the other hand, coumestanes (1-3) were good α-glucosidase inhibitors (IC(50) = 6.0-42.6 μM). In kinetic analysis, the most potent neuraminidase inhibitors (5-10) were noncompetitive. HPLC analysis indicated that most pterocarpan synthesis began from the R3 stage, and a rapid change of pterocarpan concentrations was observed between the R4 and R7 stages.