The purification and characterization of deoxycytidine kinase from calf thymus

A facile and fast approach for the purification of deoxycytidine kinase (dCK) from calf thymus was developed using a fast performance liquid chromatography system. A 73-fold enrichment of the enzyme was noted compared to unfractionated dCK. Characterization studies demonstrated that dCK had a molecular mass of 31 kDa using SDS–PAGE, an optimum pH of 7.0 and the enzyme maintained stability between 30 and 40°C. The rapid preparation of dCK demonstrated here will be valuable in the synthesis of nucleotide analogs.     

Echinostoma revolutum and Echinoparyphium recurvatum recovered from house rats in Yangyang-gun, Kangwon-do

During an investigation on intestinal flukes of house rats in Yangyang-gun, Kangwon-do, a total of 6 species of trematodes belonging to 3 families; Echinostomatidae (Echinostoma hortense, E. cinetorchis, E. revolutum and Echinoparyphium recurvatum), Diplostomidae (Fibricola seoulensis) and Plagiorchiidae (Plagiorchis muris), were recovered from two adult rats. E. revolutum and E. recurvatum were new trematode faunae of rats in Korea. E. revolutum had an elongated body, 5.3-6.0 mm long and 1.0-1.3 mm wide. The total number of collar spines was 35-37 including 5 end group ones on each ventral corner. Its coiled uterus contained numerous eggs. E. recurvatum also had an elongated body, 3.5-4.7 mm long and 0.50-0.65 mm wide. It had total 45 collar spines including 4 end group ones. The uterus was short with only a few eggs. It has been first confirmed by this study that E. revolutum and E. recurvatum are indigenously distributed among house rats in Korea.     

Experimental life history of Echinostoma cinetorchis

The life history of Echinostoma cinetorchis was completed in the laboratory using Hippeutis cantori as the first and second intermediate host. The incubation for maturation of eggs and hatching of miracidia took 24 days at 28 degrees C. On the 66th day after miracidial challenge, 16 snails were crushed and examined for the presence of E. cinetorchis larvae. The metacercariae were detected in all of the snails, and from three of them were found the rediae and cercariae. The morphological characteristics of the larvae and the experimentally obtained adults were compatible with that of E. cinetorchis.     

Kinetics of enzymatic hydrolysis of olive oil in biphasic organic-aqueous systems

A theoretical model for the lipase-catalyzed hydrolysis of high-concentration olive in biphasic isooctane-aqueous systems has been proposed and confirmed by experiments. The enzymatic reaction of the Michaelis-Menten type that occurred at the interface between organic and aqueous phases was assumed in deriving the rate equations, from which the maximum reaction rate could be obtained by carefully adjusting the volume ratio between the two phases to the optimal value. Equilibrium conversions higher than 98% for 0.1 g/L olive oil in isooctane were attained for systems with volume ratios up to one. Fractions of lipase and lipase-substrate complex adsorbed at the interface increased and seemed to approach to asymptotic values asthe rotation speed of impeller increased. Activity of the lipase showed no apparent change between 26 and 37 degrees C, but decrease rapidly with temperature above 43 degrees C. The methodology presented in this work might be used to find kinetic parameters for reactor design and scaleup.     

PAF-Myc-Controlled Cell Stemness Is Required for Intestinal Regeneration and Tumorigenesis

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Identification of Novel Cytotoxic Peptide KENPVLSLVNGMF from Marine Sponge <Emphasis Type="Italic">Xestospongia testudinaria</Emphasis>, with Characterization of Stability in Human Serum

Resistance and side effects are common problems for anticancer drugs used in chemotherapy. Thus, continued research to discover novel and specific anticancer drugs is obligatory. Marine sponges hold great promise as a source of potent cytotoxic peptides with future applications in cancer treatments. This study aimed to purify and identify cytotoxic peptides from the protein hydrolysates of the giant barrel sponge Xestospongia testudinaria, guided by a cytotoxicity assay based on the human cervical cancer cell line (HeLa). Comparison among trypsin, chymotrypsin, papain and alcalase hydrolysates of X. testudinaria revealed papain hydrolysate (PH) to be the most active. PH was purified consecutively by membrane ultrafiltration, gel filtration chromatography, and reversed-phase high performance liquid chromatography (RP-HPLC). Following liquid chromatography-tandem mass spectrometric analysis, two peptides were identified from the most cytotoxic RP-HPLC fraction: KENPVLSLVNGMF and LLATIPKVGVFSILV. Between the two, only the synthetic peptide KENPVLSLVNGMF showed cytotoxicity toward HeLa cells in a dose-dependent manner. KENPVLSLVNGMF (EC₅₀ 0.67 mM) was 3.8-fold more cytotoxic compared with anticancer drug 5-fluorouracil (EC₅₀ 2.56 mM). Furthermore, KENPVLSLVNGMF show only marginal 5% cytotoxicity to Hek293, a non-cancerous, human embryonic kidney cell line, when tested at 0.67 mM. The half-life of the peptide was 3.2?±?0.5 h in human serum in vitro, as revealed by RP-HPLC analyses. These results suggest that KENPVLSLVNGMF identified from X. testudinaria papain hydrolysate has potential applications as peptide lead in future development of potent and specific anticancer drugs.     

Cloning and different expression of ATP synthase genes between propargite resistant and susceptible strains of Tetranychus cinnabarinus (Acarina: Tetranychidae)

The carmine spider mite, Tetranychus cinnabarinus (Boisduval), is a serious phytophagous mite damaging important crops and can rapidly develop resistance to acaricides. Mitochondrial ATP synthase (F1F0 ATP synthase) is an important target site of acaricides. The role of ATP synthase in acaricide resistance remains unclear at the molecular level. In this study, twelve full-length cDNAs of ATP synthase genes were cloned and characterized from T. cinnabarinus and their expression levels were determined for both progargite-resistant and susceptible strains. The effect of propargite exposure on gene expression was also evaluated. Analyses of gene expression revealed that TcATPsynU-2, TcATPsynF0-2 and TcATPsynF0-4 were significantly down-regulated in the progargite-resistant strain. TcATPsynF0-2 and TcATPsynF0-4 had a strong response to progargite exposure. The results suggest that lower levels of TcATPsynU-2, TcATPsynF0-2 and TcATPsynF0-4 expression might be related to propargite-resistance observed in the resistant T. cinnabarinus. This is the first attempt to identify specific ATPase genes involved in propargite resistance in T. cinnabarinus.     

Response to Comment on “Retinal pulse wave velocity measurement using spectral‐domain optical coherence tomography”

Spahr et al. recently commented on our latest paper “Retinal pulse wave velocity measurement using spectral‐domain optical coherence tomography” with a conclusion that the measured retinal pulse wave velocity (rPWV) in our paper was contradictory to theoretical predictions and previously published results. However, the theoretical predictions by Spahr et al. based on Moens‐Korteweg equation are questionable, since the Moens‐Korteweg equation should not be used for small arteries like retinal arteries. Previously, various measurements of rPWV using different technologies have been reported. The results on human and rats are not consistent. As the rPWV is an unknown value, we argue that the time delay derived between 2 arterial sites should be verified to see if the delay truly represents the pulse wave transit time. In the future, special emphasis should be placed on demonstration of the reproducibility of technologies and data analysis of large samples.     

Structural and functional insights into MCR-2 mediated colistin resistance

正Dear Editor,The spread of antibiotic resistance genes among bacteria is a serious and growing threat to global health(Peleg and Hooper, 2010). One emerging case is transferable genes found in bacteria-encoding enzymes resistant to colistin.