Dirofilaria repens in Vietnam: detection of 10 eye and subcutaneous tissue infection cases identified by morphology and molecular methods

From 2006 to 2010, hospitals in Hanoi treated 10 human patients for dirofilariasis. The worms were collected from parasitic places, and identification of the species was completed by morphology and molecular methods. Ten parasites were recovered either from the conjunctiva (n=9) or subcutaneous tissue (n=1). The parasites were 4.0-12.5 cm in length and 0.5-0.6 mm in width. Morphological observations suggested all parasites as Dirofilaria repens. Three of the 10 parasites (1 from subcutaneous tissue and 2 from eyes) were used for molecular confirmation of the species identification. A portion of the mitochondrial cox1 (461 bp) was amplified and sequenced. Nucleotide and amino acid homologies were 95% and 99-100%, respectively, when compared with D. repens (Italian origin, GenBank AJ271614; DQ358814). This is the first report of eye dirofilariasis and the second report of subcutaneous tissue dirofilariasis due to D. repens in Vietnam.     

The Arabidopsis nucleotidyl transferase HESO1 uridylates unmethylated small RNAs to trigger their degradation

MicroRNAs (miRNAs), small interfering RNAs (siRNAs), and piwi-interacting RNAs (piRNAs) impact numerous biological processes in eukaryotes. In addition to biogenesis, turnover contributes to the steady-state levels of small RNAs. One major factor that stabilizes miRNAs and siRNAs in plants as well as siRNAs and piRNAs in animals is 2'-O-methylation on the 3' terminal ribose by the methyltransferase HUA ENHANCER1 (HEN1) [1-6]. Genetic studies with Arabidopsis, Drosophila, and zebrafish hen1 mutants show that 2'-O-methylation protects small RNAs from 3'-to-5' truncation and 3' uridylation, the addition of nontemplated nucleotides, predominantly uridine [2, 7, 8]. Uridylation is a widespread phenomenon that is not restricted to small RNAs in hen1 mutants and is often associated with their reduced accumulation ([7, 9, 10]; reviewed in [11]). The enzymes responsible for 3' uridylation of small RNAs when they lack methylation in plants or animals have remained elusive. Here, we identify the Arabidopsis HEN1 SUPPRESSOR1 (HESO1) gene as responsible for small RNA uridylation in hen1 mutants. HESO1 exhibits terminal nucleotidyl transferase activity, prefers uridine as the substrate nucleotide, and is completely inhibited by 2'-O-methylation. We show that uridylation leads to miRNA degradation, and the degradation is most likely through an enzyme that is distinct from that causing the 3' truncation in hen1 mutants.     

Synthesis and biological evaluation of novel heterocyclic derivatives of combretastatin A-4

A novel series of combretastatin A-4 heterocyclic analogues was prepared by replacement of the B ring with indole, benzofurane or benzothiophene, attached at the C2 position. These compounds were evaluated for their abilities to inhibit tubulin assembly: derivative cis 3b, having a benzothiophene, showed an activity similar to those of colchicine or deoxypodophyllotoxine. The antiproliferative and antimitotic properties of cis 3b against keratinocyte cancer cell lines were also evaluated and the intracellular organization of microtubules in the cells after treatment with both stereoisomers of 3b was also determined, using confocal microscopy.     

Circadian preference modulates the neural substrate of conflict processing across the day

Human morning and evening chronotypes differ in their preferred timing for sleep and wakefulness, as well as in optimal daytime periods to cope with cognitive challenges. Recent evidence suggests that these preferences are not a simple by-product of socio-professional timing constraints, but can be driven by inter-individual differences in the expression of circadian and homeostatic sleep-wake promoting signals. Chronotypes thus constitute a unique tool to access the interplay between those processes under normally entrained day-night conditions, and to investigate how they impinge onto higher cognitive control processes. Using functional magnetic resonance imaging (fMRI), we assessed the influence of chronotype and time-of-day on conflict processing-related cerebral activity throughout a normal waking day. Sixteen morning and 15 evening types were recorded at two individually adapted time points (1.5 versus 10.5 hours spent awake) while performing the Stroop paradigm. Results show that interference-related hemodynamic responses are maintained or even increased in evening types from the subjective morning to the subjective evening in a set of brain areas playing a pivotal role in successful inhibitory functioning, whereas they decreased in morning types under the same conditions. Furthermore, during the evening hours, activity in a posterior hypothalamic region putatively involved in sleep-wake regulation correlated in a chronotype-specific manner with slow wave activity at the beginning of the night, an index of accumulated homeostatic sleep pressure. These results shed light into the cerebral mechanisms underlying inter-individual differences of higher-order cognitive state maintenance under normally entrained day-night conditions.     

Integrated organic–aqueous biocatalysis and product recovery for quinaldine hydroxylation catalyzed by living recombinant Pseudomonas putida

In an earlier study, biocatalytic carbon oxyfunctionalization with water serving as oxygen donor, e.g., the bioconversion of quinaldine to 4-hydroxyquinaldine, was successfully achieved using resting cells of recombinant Pseudomonas putida, containing the molybdenum-enzyme quinaldine 4-oxidase, in a two-liquid phase (2LP) system (ütkür et al. J Ind Microbiol Biotechnol 38:1067-1077, 2011). In the study reported here, key parameters determining process performance were investigated and an efficient and easy method for product recovery was established. The performance of the whole-cell biocatalyst was shown not to be limited by the availability of the inducer benzoate (also serving as growth substrate) during the growth of recombinant P. putida cells. Furthermore, catalyst performance during 2LP biotransformations was not limited by the availability of glucose, the energy source to maintain metabolic activity in resting cells, and molecular oxygen, a possible final electron acceptor during quinaldine oxidation. The product and the organic solvent (1-dodecanol) were identified as the most critical factors affecting biocatalyst performance, to a large extent on the enzyme level (inhibition), whereas substrate effects were negligible. However, none of the 13 alternative solvents tested surpassed 1-dodecanol in terms of toxicity, substrate/product solubility, and partitioning. The use of supercritical carbon dioxide for phase separation and an easy and efficient liquid-liquid extraction step enabled 4-hydroxyquinaldine to be isolated at a purity of >99.9% with recoveries of 57 and 84%, respectively. This study constitutes the first proof of concept on an integrated process for the oxyfunctionalization of toxic substrates with a water-incorporating hydroxylase.     

Crystal structure of malonyl CoA-Acyl carrier protein transacylase from Xanthomanous oryzae pv. oryzae and its proposed binding with ACP

Xanthomonas oryzae pv. oryzae (Xoo) is a plant bacterial pathogen that causes bacterial blight (BB) disease, resulting in serious production losses of rice. The crystal structure of malonyl CoA-acyl carrier protein transacylase (XoMCAT), encoded by the gene fabD (Xoo0880) from Xoo, was determined at 2.3 Å resolution in complex with N-cyclohexyl-2-aminoethansulfonic acid. Malonyl CoA-acyl carrier protein transacylase transfers malonyl group from malonyl CoA to acyl carrier protein (ACP). The transacylation step is essential in fatty acid synthesis. Based on the rationale, XoMCAT has been considered as a target for antibacterial agents against BB. Protein-protein interaction between XoMCAT and ACP was also extensively investigated using computational docking, and the proposed model revealed that ACP bound to the cleft between two XoMCAT subdomains.     

Distribution of polyunsaturated fatty acids in red algae of the genus Gracilaria, a promising source of prostaglandins

The fatty acid (FA) composition and the content of the prostaglandin PGE₂ were determined in the red algae Gracilaria vermiculophylla and G. austramaritima from Peter the Great Bay (Sea of Japan), as well as in G. tenuistupitata, G. ?hangii, and G. bailiniae from lagoons in southern Vietnam (in the South China Sea). Polyunsaturated FA (PUFA) comprised 49?C56% of the total FAs in algae from the Sea of Japan, while in algae from the South China Sea their share was 20% at most. The content of arachidonic acid (20:4n-6) in the total FAs of G. vermiculophylla was as high as 45.4%, while the level of 20:4n-6 in Gracilaria from coastal waters of Vietnam did not exceed 12.5%. G. austramaritima stood out for its high content of eicosapentaenoic acid 20:5n-3 (33.5%). The ratios of 20:4n-6/20:5n-3 in G. vermiculophylla, G. austramaritima, G. tenuistupitata, G. changii, and G. bailiniae were 10.6, 0.3, 3.9, 4.0, and 1.5, respectively. The content of PGE₂ was the highest (286 ??g/g dry weight) in G. vermiculophylla from the Sea of Japan and did not exceed 20 ??g/g dry weights in other Gracilaria species. This study showed that it is possible to introduce G. vermiculophylla from the Sea of Japan into the mariculture of northern Vietnam. In the experiment, during 3 weeks of cultivation, the biomass of introduced Gracilaria increased 1.2?C1.3 times in a sea lagoon in Vietnam and 1.5?C2 times in an aquarium; the algal growth rates were 1.57 ± 0.21% per day. In cultivated Gracilaria, the level of 20:4n-6 decreased to 5.9% (20:4n-6/20:5n-3 = 2.3) and the level of PGE₂ decreased to 12 ??g/g in dry weight. The PUFA compositions of G. vermiculophylla from various natural populations differed insignificantly; however, the stress caused by introduction led to a sharp reduction in the content of 20:4n-6, which was probably connected with a decreased biosynthesis rate of PUFAs of the n-6 series. At the same time, approximately equal amounts of PGE₂ methyl ester were extracted from natural and cultivated G. vermiculophylla after treatment by a method proposed for obtaining prostaglandins. Thus, the cultivation conditions evidently did not influence the prostaglandin biosynthesis enzyme complex in G. vermiculophylla; this species, when grown in mariculture, can be used as a source of prostaglandins.     

Quantitative 13C NMR spectroscopy. Chemical structure of kraft and nitrosated lignins

Quantitative ¹³C NMR spectroscopy has been used to study the chemical structure of industrial kraft lignin, obtained from softwood pulping, and its nitrosated derivatives, which demonstrate high inhibition activity in the polymerization of unsaturated hydrocarbons.