Morphological,molecular and MALDI-TOF MS identification of ticks and tick-associated pathogens in Vietnam

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising and reliable tool for arthropod identification, including the identification of alcohol-preserved ticks based on extracted leg protein spectra. In this study, the legs of 361 ticks collected in Vietnam, including 251 Rhiphicephalus sanguineus s.l, 99 Rhipicephalus (Boophilus) microplus, two Amblyomma varanensis, seven Dermacentor auratus, one Dermacentor compactus and one Amblyomma sp. were submitted for MALDI-TOF MS analyses. Spectral analysis showed intra-species reproducibility and inter-species specificity and the spectra of 329 (91%) specimens were of excellent quality. The blind test of 310 spectra remaining after updating the database with 19 spectra revealed that all were correctly identified with log score values (LSV) ranging from 1.7 to 2.396 with a mean of 1.982 ± 0.142 and a median of 1.971. The DNA of several microorganisms including Anaplasma platys, Anaplasma phagocytophilum, Anaplasma marginale, Ehrlichia rustica, Babesia vogeli, Theileria sinensis, and Theileria orientalis were detected in 25 ticks. Co-infection by A. phagocytophilum and T. sinensis was found in one Rh. (B) microplus.     

ZxAKT1 is essential for K+ uptake and K+/Na+ homeostasis in the succulent xerophyte Zygophyllum xanthoxylum

The inward‐rectifying K⁺ channel AKT1 constitutes an important pathway for K⁺ acquisition in plant roots. In glycophytes, excessive accumulation of Na⁺ is accompanied by K⁺ deficiency under salt stress. However, in the succulent xerophyte Zygophyllum xanthoxylum, which exhibits excellent adaptability to adverse environments, K⁺ concentration remains at a relatively constant level despite increased levels of Na⁺ under salinity and drought conditions. In this study, the contribution of ZxAKT1 to maintaining K⁺ and Na⁺ homeostasis in Z. xanthoxylum was investigated. Expression of ZxAKT1 rescued the K⁺‐uptake‐defective phenotype of yeast strain CY162, suppressed the salt‐sensitive phenotype of yeast strain G19, and complemented the low‐K⁺‐sensitive phenotype of Arabidopsis akt1 mutant, indicating that ZxAKT1 functions as an inward‐rectifying K⁺ channel. ZxAKT1 was predominantly expressed in roots, and was induced under high concentrations of either KCl or NaCl. By using RNA interference technique, we found that ZxAKT1‐silenced plants exhibited stunted growth compared to wild‐type Z. xanthoxylum. Further experiments showed that ZxAKT1‐silenced plants exhibited a significant decline in net uptake of K⁺ and Na⁺, resulting in decreased concentrations of K⁺ and Na⁺, as compared to wild‐type Z. xanthoxylum grown under 50 mm NaCl. Compared with wild‐type, the expression levels of genes encoding several transporters/channels related to K⁺/Na⁺ homeostasis, including ZxSKOR, ZxNHX, ZxSOS1 and ZxHKT1;1, were reduced in various tissues of a ZxAKT1‐silenced line. These findings suggest that ZxAKT1 not only plays a crucial role in K⁺ uptake but also functions in modulating Na⁺ uptake and transport systems in Z. xanthoxylum, thereby affecting its normal growth.     

Ozone sensitivity of four Pakchoi cultivars with different leaf colors: physiological and biochemical mechanisms

Ozone (O₃) is important air pollutant inducing severe losses of horticultural production. Cultivars of the same species, but with different leaf colors, may differ in their ozone sensitivity. However, it has not been clarified yet if different leaf coloration influences such a sensitivity. In this study, two purple-leafed and two green-leafed cultivars of Pakchoi were selected for ozone fumigation (240 ± 20 nmol mol^–1, 09:00–16:00 h). Elevated O₃ decreased chlorophyll content, increased anthocyanin (Ant) content, damaged cell membrane integrity, enhanced antioxidative enzyme activities, depressed photosynthetic rate (P _N) and stomatal conductance (g _s), inhibited maximal quantum yield (F_v/F_m) and effective quantum yield [Y_II] of PSII photochemistry, and caused visible injury. Purple-leafed cultivars with higher Ant contents were more tolerant than green-leafed cultivars as indicated by lower relative enhancement in malondialdehyde content and lower relative losses in P _N, g _s, F_v/F_m, and Y_II. The higher ability to synthesize Ant in the purple-leafed cultivars contributed to their higher photoprotective ability.     

Application of chitooligosaccharides as antioxidants in beer to improve the flavour stability by protecting against beer staling during storage

Objective

To improve beer flavour stability by adding chitooligosaccharides that prevent formation of staling compounds and also scavenge radicals in stale beer.

Results

Chitooligosaccharides, at 0.001–0.01%, inhibited the formation of staling compounds in forced aged beer. The formation of 5-hydroxymethylfurfural, trans-2-nonenal and phenylacetaldehyde were decreased by 105, 360 and 27%, respectively, when compared with those in stale beer without chitooligosaccharide addition. The capability of chitooligosaccharides to prevent staling compound formation depended on their molecular size (2 or 3 kDa). The DPPH/hydroxyl radical scavenging activity in fresh beer significantly lower than that in forced aged beer in the presence of chitooligosaccharides. When compared with stale beer without added chitooligosaccharides, the radical scavenging activity could be increased by adding chitooligosaccharides to forced aged beer.

Conclusions

Chitooligosaccharides play an active part in the prevention of beer flavour deterioration by inhibiting the formation of staling compounds and increasing radical scavenging activity.

     

Elevated expression of EBV and TLRs in the brain is associated with Rasmussen’s encephalitis

Rasmussen's encephalitis(RE) is a rare pediatric neurological disorder, the etiology of which remains unclear. It has been speculated that the immunopathogenesis of RE involves damage to neurons, which eventually leads to the occurrence of RE. Viral infection may be a critical factor in triggering RE immunopathogenesis. In this study, we analyzed the expression of Epstein-Barr virus(EBV) antigens as well as of Toll-like receptor 3(TLR3), TLR9, and downstream adapter TIRdomain-containing adapter-inducing interferon-β(TRIF) in the brain tissues of 26 patients with RE and 16 control individuals using immunohistochemistry(IHC). In the RE group, EBV antigens were detected in 53% of individuals at various expression levels. In contrast, there was no detectable EBV antigen expression in control brain tissues. Moreover, we found marked increases in the expression of TLR3, TLR9, and TRIF in the brain tissues of RE patients compared with levels in the control group. Furthermore, among RE cases, EBV expression and high TLR3 expression were associated with more severe brain atrophy. Our results suggest that the elevated expression of EBV and TLRs may be involved in RE occurrence through the activation of downstream molecules.     

Flavonoids from Potentilla parvifolia Fisch. and Their Neuroprotective Effects in Human Neuroblastoma SH‐SY5Y Cells in vitro

Potentilla parvifolia Fisch . (Rosaceae) is a traditional medicinal plant in P. R. China. In this study, seven flavonoids, ayanin ( 1 ), tricin ( 2 ), quercetin ( 3 ), tiliroside ( 4 ), miquelianin ( 5 ), isoquercitrin ( 6 ), and astragalin ( 7 ), were separated and purified from ethyl acetate extractive fractions from ethanol extracts of P. parvifolia using a combination of sevaral chromatographic methods. The human neuroblastoma SH‐SY5Y cells were differentiated with all trans‐retinoic acid and treated with okadaic acid to induce tau protein phosphorylation and synaptic atrophy, which could establish an Alzheimer's disease cell model. The neuroprotective effects of these flavonoids in cellular were evaluated in vitro by this cell model. Results from the Western blot and morphology analysis suggested that compounds 3 and 4 had the better neuroprotective effects.     

Genome based quantification of <Emphasis Type="Italic">Streptococcus parauberis</Emphasis> in multiple organs of infected olive flounder (<Emphasis Type="Italic">Paralichthys olivaceus</Emphasis>)

Although Streptococcus parauberis is the major bacterial pathogen affecting olive flounder, the translocation and dissemination of this pathogen in infected fish are not well understood. Therefore, we conducted real-time PCR and histopathologic examination to monitor the intensity of infection in multiple organs of the olive flounder after challenge with S. parauberis through subcutaneous injection. The bacterial burden in the fish kidney, when sampled at 0, 3, and 7 dpc, was 0, 6.2?±?4.5?×?10⁵, and 6.7?±?5.5?×?10⁶ CFU/100 mg of tissue, respectively, indicating that the infection progressed rapidly over time. Of the ten different tissues sampled, the heart and the brain were the major target organs of S. parauberis based on highest copy number as detected by our modified real-time PCR method. Histopathologic examination also showed that S. parauberis caused severe inflammation accompanied by leucocyte infiltration, connective tissue expansion, and a loss of cardiomyocytes in the brain and heart of fish sampled at dpc 7. However, the number of S. parauberis-positive fish at 3 dpc was much higher in the spleen (6/8 fish) than in the remaining organs, suggesting that the spleen is targeted in the early stages of infection relative to the heart (2/8 fish) or brain (3/8 fish). This study provides essential information for studies to find treatments for the effective elimination of S. parauberis in target organs (i.e., the brain and heart) of olive flounder.     

Revisiting the phylogeny of Wolbachia in Collembola

The endosymbiont Wolbachia has been detected in a few parthenogenetic collembolans sampled in Europe and America, including three species of Poduromorpha, two species of Entomobryomorpha, and two species of Neelipleona. Based on 16S rRNA and ftsZ gene sequences, most of the Wolbachia infecting parthenogenetic collembolans were characterized as members of supergroup E and showed concordant phylogeny with their hosts. However, the two neelipleonan symbionts form another unique group, indicating that Wolbachia has infected parthenogenetic collembolans multiple times. In this study, five parthenogenetic collembolan species were identified as hosts of Wolbachia, and four new Wolbachia strains were reported for four collembolan species sampled in China, respectively, including a neelipleonan strain from Megalothorax incertus (wMinc). Our results demonstrated that the Wolbachia multilocus sequence typing (MLST) system is superior to the 16S rRNA + ftsZ approach for phylogenetic analyses of collembolan Wolbachia. The MLST system assigned these Wolbachia of parthenogenetic collembolans to supergroup E as a unique clade, which included wMinc, supporting the monophyletic origin of Wolbachia in parthenogenetic collembolan species. Moreover, our data suggested supergroup E as one of the most divergent lineages in Wolbachia and revealed the discrepancy between the phylogenies of Wolbachia from parthenogenetic collembolans and their hosts, which may result from the high level of genetic divergence between collembolan Wolbachia, in association with the geographic differentiation of their hosts, or the possible horizontal transmission of Wolbachia between different collembolan species.     

Arf GTPase-activating protein ASAP1 interacts with Rab11 effector FIP3 and regulates pericentrosomal localization of transferrin receptor-positive recycling endosome

ADP-ribosylation factors (Arfs) and Arf GTPase-activating proteins (GAPs) are key regulators of membrane trafficking and the actin cytoskeleton. The Arf GAP ASAP1 contains an N-terminal BAR domain, which can induce membrane tubulation. Here, we report that the BAR domain of ASAP1 can also function as a protein binding site. Two-hybrid screening identified FIP3, which is a putative Arf6- and Rab11-effector, as a candidate ASAP1 BAR domain-binding protein. Both coimmunoprecipitation and in vitro pulldown assays confirmed that ASAP1 directly binds to FIP3 through its BAR domain. ASAP1 formed a ternary complex with Rab11 through FIP3. FIP3 binding to the BAR domain stimulated ASAP1 GAP activity against Arf1, but not Arf6. ASAP1 colocalized with FIP3 in the pericentrosomal endocytic recycling compartment. Depletion of ASAP1 or FIP3 by small interfering RNA changed the localization of transferrin receptor, which is a marker of the recycling endosome, in HeLa cells. The depletion also altered the trafficking of endocytosed transferrin. These results support the conclusion that ASAP1, like FIP3, functions as a component of the endocytic recycling compartment.     

Group additive regression models for genomic data analysis

One important problem in genomic research is to identify genomic features such as gene expression data or DNA single nucleotide polymorphisms (SNPs) that are related to clinical phenotypes. Often these genomic data can be naturally divided into biologically meaningful groups such as genes belonging to the same pathways or SNPs within genes. In this paper, we propose group additive regression models and a group gradient descent boosting procedure for identifying groups of genomic features that are related to clinical phenotypes. Our simulation results show that by dividing the variables into appropriate groups, we can obtain better identification of the group features that are related to the phenotypes. In addition, the prediction mean square errors are also smaller than the component-wise boosting procedure. We demonstrate the application of the methods to pathway-based analysis of microarray gene expression data of breast cancer. Results from analysis of a breast cancer microarray gene expression data set indicate that the pathways of metalloendopeptidases (MMPs) and MMP inhibitors, as well as cell proliferation, cell growth, and maintenance are important to breast cancer-specific survival.