Ethanol-Mediated Variations in Cellular Fatty Acid Composition and Protein Profiles of Two Genotypically Different Strains of Escherichia coli O157:H7

Two strains of Escherichia coli O157:H7 were grown in tryptic soy broth (TSB, pH 7.1) supplemented with 0, 2.5, 5.0, 7.5, and 10% ethanol at 30°C for up to 54 h. Growth rates in TSB supplemented with 0, 2.5, and 5.0% ethanol decreased with an increase in ethanol concentration. Growth was not observed in TSB supplemented with 7.5 or 10% ethanol. The pH of TSB containing 5.0% ethanol decreased to 5.8 within 12 h and then increased to 7.0 at 54 h. The ethanol content in TSB supplemented with 2.5 or 5.0% ethanol did not change substantially during the first 36 h of incubation but decreased slightly thereafter, indicating utilization or degradation of ethanol by both strains. Glucose was depleted in TSB supplemented with 0, 2.5, or 5.0% ethanol within 12 h. Cells grown under ethanol stress contained a higher amount of fatty acids. With the exceptions of cis-oleic acid and nonadecanoic acid, larger amounts of fatty acid were present in stationary-phase cells of the two strains grown in TSB supplemented with 5.0% ethanol for 30 h than in cells grown in TSB without ethanol for 22 h. The trans-oleic acid content was 10-fold higher in the cells grown in TSB with 5.0% ethanol than those grown in TSB without ethanol. In contrast, cis-oleic acid was not detected in ethanol-stressed cells but was present at concentrations of 0.32 and 0.36 mg/g of cells of the two strains grown in TSB without ethanol. Protein content was higher in ethanol-stressed cells than in nonstressed cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles varied qualitatively as affected by the strain and the presence of ethanol in TSB. An ethanol-mediated protein (28 kDa) was observed in the ethanol-stressed cells but not in control cells. It is concluded that the two test strains of E. coli O157:H7 underwent phenotypic modifications in cellular fatty acid composition and protein profiles in response to ethanol stress. The potential for cross protection against subsequent stresses applied in food preservation technologies as a result of these changes is under investigation.     

Changes in the potential habitats of 10 dominant evergreen broad-leaved tree species in the Taiwan-Japan archipelago

Ecosystem vulnerability to climate change remains elusive in the species-rich Taiwan-Japan archipelago. We predicted potential habitats (PHs) of ten dominant evergreen broad-leaved tree species by using the current and twenty potential climate change scenarios using generalised additive models. The presence/absence records of each species, extracted from vegetation database, were used as response variables. Four climatic and one spatial variables were used as explanatory variables. The results showed that the interaction terms of spatial variable, indicating historical range shifts or species interactions, restricted the distribution of all the target species as much as that by the each climatic variable. The PHs of all the target species were predicted to consistently increase, and in particular, to expand northward and upward to the cool temperate zone. However, the PHs were predicted to decrease within the range of 23.6–38.1 % in the Ryukyu Islands for Castanopsis sieboldii and Elaeocarpus japonica, respectively, and within the range of 32.4–42.3 % in Taiwan for Camellia japonica and Distylium racemosum, respectively. These findings suggest that the four species will be vulnerable at the southern range limits; however, the remaining six species will potentially increase within the PH areas in the future at all regions.     

The role of the miR399-<Emphasis Type="Italic">PHO2</Emphasis> module in the regulation of flowering time in response to different ambient temperatures in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

A moderate change in ambient temperature significantly affects plant physiology including flowering time. MiR399 and its target gene PHOSPHATE 2 (PHO2) are known to play a role in the maintenance of phosphate homeostasis. However, the regulation of flowering time by the miR399-PHO2 module has not been investigated. As we have previously identified miR399 as an ambient temperature-responsive miRNA, we further investigated whether a change in expression of the miR399-PHO2 module affects flowering time in response to ambient temperature changes. Here, we showed that miR399b-overexpressing plants and a loss-of-function allele of PHO2 (pho2) exhibited an early flowering phenotype only at normal temperature (23°C). Interestingly, their flowering time at lower temperature (16°C) was similar to that of wild-type plants, suggesting that alteration in flowering time by miR399 and its target PHO2 was seen only at normal temperature (23°C). Flowering time ratio (16°C/23°C) revealed that miR399b-overexpressing plants and pho2 mutants showed increased sensitivity to ambient temperature changes. Expression analysis indicated that expression of TWIN SISTER OF FT (TSF) was increased in miR399b-overexpressing plants and pho2 mutants at 23°C, suggesting that their early flowering phenotype is associated with TSF upregulation. Taken together, our results suggest that miR399, an ambient temperature-responsive miRNA, plays a role in ambient temperature-responsive flowering in Arabidopsis.     

Cloning of the rainbow trout (Oncorhynchus mykiss) Mx2 and Mx3 cDNAs and characterization of trout Mx protein expression in salmon cells.

Two rainbow trout (Oncorhynchus mykiss) Mx cDNAs were cloned by using RACE (rapid amplification of cDNA ends) PCR and were designated RBTMx2 and RBTMx3. The deduced RBTMx2 and RBTMx3 proteins were 636 and 623 amino acids in length with molecular masses of 72 and 70.8 kDa, respectively. These proteins, along with the previously described RBTMx1 protein (G. D. Trobridge and J. A. Leong, J. Interferon Cytokine Res. 15:691-702, 1995), have between 88.7 and 96.6% identity at the amino acid level. All three proteins contain the tripartite GTP binding domain and leucine zipper motif common to Mx proteins. A monospecific polyclonal antiserum to an Escherichia coli-expressed fragment of RBTMx3 was generated, and that reagent was found to react with all three rainbow trout Mx proteins. Subsequently, endogenous Mx production in RTG-2 cells induced with poly(IC) double-stranded RNA was detected by immunoblot analysis. The cellular localization of the rainbow trout proteins was determined by transient expression of the RBTMx cDNAs in CHSE-214 (chinook salmon embryo) cells. A single-cell transient-transfection assay was used to examine the ability of each Mx cDNA clone to inhibit replication of the fish rhabdovirus infectious hematopoietic necrosis virus (IHNV). No significant inhibition in the accumulation of the IHNV nucleoprotein was observed in cells expressing either trout Mx1, Mx2, or Mx3 in transiently transfected cells.     

A novel in vitro retinal differentiation model by co-culturing adult human bone marrow stem cells with retinal pigmented epithelium cells

Human retinal pigment epithelium (HRPE) cells are important in maintaining the normal physiology within the neurosensory retina and photoreceptors. Recently, transplantation of HRPE has become a possible therapeutic approach for retinal degeneration. By negative immunoselection (CD45 and glycophorin A), in this study, we have isolated and cultivated adult human bone marrow stem cells (BMSCs) with multilineage differentiation potential. After a 2- to 4-week culture under chondrogenic, osteogenic, adipogenic, and hepatogenic induction medium, these BMSCs were found to differentiate into cartilage, bone, adipocyte, and hepatocyte-like cells, respectively. We also showed that these BMSCs could differentiate into neural precursor cells (nestin-positive) and mature neurons (MAP-2 and Tuj1-positive) following treatment of neural selection and induction medium for 1 month. Furthermore, the plasticity of BMSCs was confirmed by initiating their differentiation into retinal cells and photoreceptor lineages by co-culturing with HRPE cells. The latter system provides an ex vivo expansion model of culturing photoreceptors for the treatment of retinal degeneration diseases.     

Pierce's Disease of Grapevines in Taiwan: Isolation,Cultivation and Pathogenicity of Xylella fastidiosa

Characteristic symptoms of Pierce's disease (PD) in grapevines (Vitis vinifera L.) were observed in 2002 in the major grape production fields of central Taiwan. Disease severity in vineyards varied, and all investigated grape cultivars were affected. Diseased tissues were collected from fields for subsequent isolation and characterization of the causal agent of the disease (Xylella fastidiosa). Koch's postulates were fulfilled by artificially inoculating two purified PD bacteria to grape cultivars Kyoho, Honey Red and Golden Muscat. The inoculated plants developed typical leaf‐scorching symptoms, and similar disease severity developed in the three cultivars from which the bacterium was readily re‐isolated, proving that the leaf scorch of grapevines in Taiwan is caused by the fastidious X. fastidiosa. This confirmed PD of grapevines is also the first report from the Asian Continent. Phylogenetic analyses were performed by comparing the 16S rRNA gene and 16S‐23S rRNA internal transcribed spacer region (16S‐23S ITS) of 12 PD strains from Taiwan with the sequences of 13 X. fastidiosa strains from different hosts and different geographical areas. Results showed that the PD strains of Taiwan were closely related to the American X. fastidiosa grape strains but not to the pear strains of Taiwan, suggesting that the X. fastidiosa grape and pear strains of Taiwan may have evolved independently from each other.     

Risk Factors for Renal Scarring and Deterioration of Renal Function in Primary Vesico-Ureteral Reflux Children: A Long-Term Follow-Up Retrospective Cohort Study

Background and Purpose

The aim was to identify the risk factors for renal scarring and deteriorating renal function in children with primary vesico-ureteral reflux (VUR).

Materials and Methods

Patients with primary VUR admitted to the National Cheng Kung University Hospital were retrospectively analyzed. The outcomes were renal scarring, assessed by technetium-99 m dimercaptosuccinic acid scanning, and renal function, assessed by estimated glomerular filtration rate. Univariate and multivariate models were applied to identify the corresponding independent predictors.

Results

A total of 173 patients with primary VUR were recruited. The median age of VUR diagnosis was 10.0 months (IQR: 4.0–43.0 months). After adjusting for confounding factors, it was found that older age of VUR diagnosis (≥5 years vs. <1 year, adjusted OR = 2.78, 95% CI = 1.00–7.70, p = 0.049), higher grade of VUR (high grade [IV–V] vs. none, adjusted OR = 15.17, 95% CI = 5.33–43.19, p<0.0001; low grade [I–III] vs. none, adjusted OR = 5.72, 95% CI = 2.43–13.45, p<0.0001), and higher number of UTI (≥2 vs. 0, adjusted OR = 3.21, 95% CI = 1.06–9.76, p = 0.039) were risk factors for renal scarring, whereas a younger age of VUR diagnosis (≥5 years vs. <1 year, adjusted HR = 0.16, 95% CI: 0.05–0.51, p = 0.002), renal scarring (yes vs. no, adjusted HR = 3.66, 95% CI: 1.32–10.16, p = 0.013), and APN (yes vs. no, adjusted HR = 3.10, 95% CI: 1.05–9.14, p = 0.041) were risk factors for developing chronic kidney disease stage 2 or higher.

Conclusions

Our findings expand on the current knowledge of risk factors for renal scarring and deteriorating renal function, and this information can be used to modify the management and treatment of VUR.     

Biotic communities of freshwater marshes and mangroves in relation to saltwater incursions: implications for wetland regulation

An ecosystem-level study was conducted in the Guandu wetlands insubtropical coastal Taiwan to examine how salinity influences the abundance,diversity, and structure of biotic communities. We surveyed eight permanentstudy sites, spanning freshwater marshes, to the gate on the dyke, andmesohaline mangroves representing a gradient of the extent of saltwaterincursions. Analyses of abiotic variables showed that salinity was the primarydetermining factor for discriminating habitat types in the wetlands, butcommunities differed in their sensitivity to salinity. The composition of plantand insect communities was most affected by the salinity gradient, suggestingthe utility of these communities for ecological monitoring of saltwaterincursions. However, spatial changes in communities at higher trophic levels,including macrobenthos, mollusks, fish, and birds, could not be explained simplyby the salinity gradient. Instead, changes in these communities were morerelevant to the composition of other biotic communities. Our results show thatspecies richness and diversity of plant communities were higher in the marshesthan in the mangroves. Nevertheless, insect communities censused in themangroves had higher diversity, despite lower abundance and species richness.Macrobenthos surveyed in the mangroves showed higher biomass and number of taxa.Mollusks and fish were also more abundant at sites near the gate compared to themarsh sites. This suggests that maintaining a tidal flux by means of gateregulation is necessary for conserving the spatial heterogeneity andbiodiversity of coastal wetlands.