Demethylation of aromatic compounds by strain B10 and complete degradation of 3-methoxybenzoate in co-culture with Desulfosarcina strains

Summary A pure culture presumably of an Acetobacterium sp. from a waste water pond, strain B10, was able to grow with several methoxylated aromatic compounds by demethylation (or demethoxylation) to the corresponding hydroxilated substances. Acetate was formed from the eliminated methyl or methoxy groups and from CO₂. Demethylation of 3-methoxybenzoate occurred simultaneously with glucose or lactate fermentation if induced, methanol-grown cells of strain B10 were used as an inoculum. If 2-vanillin or 2,3-dimethoxybenzaldehyde were supplied as the only carbon sources, these substances were first oxidized to the corresponding benzoic acid derivatives and subsequently demethylated. In mixed cultures of strain B10 and Desulfosarcina variabilis or Desulfosarcina strain DSU3 the 3-hydroxybenzoate formed by strain B10 from 3-methoxybenzoate was completely degraded to acetate and presumably CO₂ by the sulphate reducers. Acetate could be oxidized to CO₂ upon extended incubation. The complete degradation of 3-methoxybenzoate to CO₂ by co-cultures of strain B10 and Desulfosarcina strains seemed to proceed via a commensalistic, rather than via a syntrophic interaction of the participating organisms. Offprint requests to: J. Winter     

Multiple Delivery of siRNA against Endoglin into Murine Mammary Adenocarcinoma Prevents Angiogenesis and Delays Tumor Growth

Endoglin is a transforming growth factor-β (TGF- β) co-receptor that participates in the activation of a signaling pathway that mediates endothelial cell proliferation and migration in angiogenic tumor vasculature. Therefore, silencing of endoglin expression is an attractive approach for antiangiogenic therapy of tumors. The aim of our study was to evaluate the therapeutic potential of small interfering RNA (siRNA) molecules against endoglin in vitro and in vivo. Therapeutic potential in vitro was assessed in human and murine endothelial cells (HMEC-1, 2H11) by determining endoglin expression level, cell proliferation and tube formation. In vivo, the therapeutic potential of siRNA molecules was evaluated in TS/A mammary adenocarcinoma growing in BALB/c mice. Results of our study showed that siRNA molecules against endoglin have a good antiangiogenic therapeutic potential in vitro, as expression of endoglin mRNA and protein levels in mouse and human microvascular endothelial cells after lipofection were efficiently reduced, which resulted in the inhibition of endothelial cell proliferation and tube formation. In vivo, silencing of endoglin with triple electrotransfer of siRNA molecules into TS/A mammary adenocarcinoma also significantly reduced the mRNA levels, number of tumor blood vessels and the growth of tumors. The obtained results demonstrate that silencing of endoglin is a promising antiangiogenic therapy of tumors that could not be used as single treatment, but as an adjunct to the established cytotoxic treatment approaches.     

Real-time in vivo visualization of oxidative stress in duckweed (Lemna minor L.)

An experimental set-up which enabled non-invasive, real-time reactive oxygen species (ROS) visualization on a whole plant level was constructed. In the test organism, Lemna minor L. (common duckweed), apoplastic and symplastic oxidative stress was evaluated by exposure to menadione (50 μM), menadione (50 μM) + ascorbate (100 μM) or neither for control. Menadione (50 μM) caused a statistically significant increase in H₂DCFDA fluorescence in the apoplast after 60 minutes of exposure. The addition of ascorbate (100 μM) in the test medium significantly decreased apoplastic oxidative stress. 50 μM menadione caused an increase in symplastic H₂DCFDA fluorescence in 57% of fronds. The exposure of L. minor plants to both menadione and ascorbate decreased the rate of fluorescence intensity accumulation in the symplast to control levels. The method has proven to be quick and straightforward and could be applied to a range of chemicals in various physiological and toxicological plant studies. The advantages of the set-up and different possible artefacts are discussed.     

DNA ploidy as a prognostic factor in rhabdomyosarcoma. Analysis of 35 cases with image cytometry

OBJECTIVE: To correlate DNA ploidy in rhabdomyosarcoma (RMS) with other prognostic factors and patient survival and to search for possible reasons for inconsistent conclusions in similar, published studies. STUDY DESIGN: DNA content was measured in archival specimens obtained from 35 patients (23 children and 12 adults) with RMS. Cell suspensions were prepared by the modified Hedley technique, stained by the modified Feulgen-thionin method and analyzed by automated high-resolution image cytometry. DNA ploidy was assessed on the basis of DNA index values. We used the chi 2 test to correlate DNA ploidy with other prognostic factors, Kaplan-Meier procedure to estimate overall survival in terms of individual prognostic factors, log-rank test to calculate differences in survival between groups and Cox multivariate regression analysis to determine the independence of variables in relation to survival. RESULTS: A statistically significant correlation was found only between DNA ploidy and histologic subtype of RMS, patient sex and patient age. A hyperdiploid DNA pattern predominated among patients with embryonal RMS, and a tetraploid pattern dominated among patients with alveolar RMS. The highest 5-year survival rate was seen among patients with hyperdiploid RMS, followed by those with diploid, tetraploid and hypertetraploid RMS. Although DNA ploidy was a significant prognostic factor in univariate analysis, it did not retain its independent prognostic value in multivariate analysis, in which patient age, tumor size and histologic subtype were the only significant factors. We found 12 articles reporting on the association between DNA ploidy and survival of patients with RMS: 6 found a correlation, and 6 did not. The main reasons for the discrepancies seem to be the inclusion of chemotherapy-treated and nontreated patients, low number of patients and differences in grouping DNA histograms. CONCLUSION: The precise prognostic value of DNA ploidy in RMS remains equivocal. Larger, cooperative studies could give statistically more reliable results.     

Repellent plants provide affordable natural screening to prevent mosquito house entry in tropical rural settings--results from a pilot efficacy study

Sustained malaria control is underway using a combination of vector control, prompt diagnosis and treatment of malaria cases. Progress is excellent, but for long-term control, low-cost, sustainable tools that supplement existing control programs are needed. Conventional vector control tools such as indoor residual spraying and house screening are highly effective, but difficult to deliver in rural areas. Therefore, an additional means of reducing mosquito house entry was evaluated: the screening of mosquito house entry points by planting the tall and densely foliated repellent plant Lantana camara L. around houses. A pilot efficacy study was performed in Kagera Region, Tanzania in an area of high seasonal malaria transmission, where consenting families within the study village planted L. camara (Lantana) around their homes and were responsible for maintaining the plants. Questionnaire data on house design, socioeconomic status, malaria prevention knowledge, attitude and practices was collected from 231 houses with Lantana planted around them 90 houses without repellent plants. Mosquitoes were collected using CDC Light Traps between September 2008 and July 2009. Data were analysed with generalised negative binomial regression, controlling for the effect of sampling period. Indoor catches of mosquitoes in houses with Lantana were compared using the Incidence Rate Ratio (IRR) relative to houses without plants in an adjusted analysis. There were 56% fewer Anopheles gambiae s.s. (IRR 0.44, 95% CI 0.28-0.68, p<0.0001); 83% fewer Anopheles funestus s.s. (IRR 0.17, 95% CI 0.09-0.32, p<0.0001), and 50% fewer mosquitoes of any kind (IRR 0.50, 95% CI 0.38-0.67, p<0.0001) in houses with Lantana relative to controls. House screening using Lantana reduced indoor densities of malaria vectors and nuisance mosquitoes with broad community acceptance. Providing sufficient plants for one home costs US $1.50 including maintenance and labour costs, (30 cents per person). L. camara mode of action and suitability for mosquito control is discussed.     

High‐Performance Platinum‐Perovskite Composite Bifunctional Oxygen Electrocatalyst for Rechargeable Zn–Air Battery

Constructing highly active electrocatalysts with superior stability at low cost is a must, and vital for the large‐scale application of rechargeable Zn–air batteries. Herein, a series of bifunctional composites with excellent electrochemical activity and durability based on platinum with the perovskite Sr(Co_0.8Fe_0.2)_0.95P_0.05O_3?δ (SCFP) are synthesized via a facile but effective strategy. The optimal sample Pt‐SCFP/C‐12 exhibits outstanding bifunctional activity for the oxygen reduction reaction and oxygen evolution reaction with a potential difference of 0.73 V. Remarkably, the Zn–air battery based on this catalyst shows an initial discharge and charge potential of 1.25 and 2.02 V at 5 mA cm^?2, accompanied by an excellent cycling stability. X‐ray photoelectron spectroscopy, X‐ray absorption near‐edge structure, and extended X‐ray absorption fine structure experiments demonstrate that the superior performance is due to the strong electronic interaction between Pt and SCFP that arises as a result of the rapid electron transfer via the Pt? O? Co bonds as well as the higher concentration of surface oxygen vacancies. Meanwhile, the spillover effect between Pt and SCFP also can increase more active sites via lowering energy barrier and change the rate‐determining step on the catalysts surface. Undoubtedly, this work provides an efficient approach for developing low‐cost and highly active catalysts for wider application of electrochemical energy devices.     

Impact of drought stress on growth and quality of miscanthus for biofuel production

Miscanthus has a high potential as a biomass feedstock for biofuel production. Drought tolerance is an important breeding goal in miscanthus as water deficit is a common abiotic stress and crop irrigation is in most cases uneconomical. Drought may not only severely reduce biomass yields, but also affect biomass quality for biofuel production as cell wall remodeling is a common plant response to abiotic stresses. The quality and plant weight of 50 diverse miscanthus genotypes were evaluated under control and drought conditions (28 days no water) in a glasshouse experiment. Overall, drought treatment decreased plant weight by 45%. Drought tolerance – as defined by maintenance of plant weight – varied extensively among the tested miscanthus genotypes and ranged from 30% to 110%. Biomass composition was drastically altered due to drought stress, with large reductions in cell wall and cellulose content and a substantial increase in hemicellulosic polysaccharides. Stress had only a small effect on lignin content. Cell wall structural rigidity was also affected by drought conditions; substantially higher cellulose conversion rates were observed upon enzymatic saccharification of drought‐treated samples with respect to controls. Both cell wall composition and the extent of cell wall plasticity under drought varied extensively among all genotypes, but only weak correlations were found with the level of drought tolerance, suggesting their independent genetic control. High drought tolerance and biomass quality can thus potentially be advanced simultaneously. The extensive genotypic variation found for most traits in the evaluated miscanthus germplasm provides ample scope for breeding of drought‐tolerant varieties that are able to produce substantial yields of high‐quality biomass under water deficit conditions. The higher degradability of drought‐treated samples makes miscanthus an interesting crop for the production of second‐generation biofuels in marginal soils.     

Physiological responses to Cd and Zn in two Cd/Zn hyperaccumulating Thlaspi species

In a model hyperaccumulation study a Cd/Zn hyperaccumulator Thlaspi caerulescens accession Ganges and a recently reported Cd/Zn hyperaccumulator Thlaspi praecox grown in increasing Cd and Zn concentrations in the substrate and in field collected polluted soil were compared. Plant biomass, concentrations of Cd and Zn, total chlorophylls and anthocyanins, antioxidative stress parameters and activities of selected antioxidative enzymes were compared. Increasing Cd, but not Zn in the substrate resulted in the increase of biomass of roots and shoots of T. praecox and T. caerulescens. The two species hyperaccumulated Cd in the shoots to a similar extent, whereas T. caerulescens accumulated more Zn in the shoots than T. praecox. Cadmium amendment decreased total chlorophyll concentration and glutathione reductase activity, and increased non-protein thiols concentration only in T. praecox, suggesting that it is less tolerant to Cd than T. caerulescens. In the field-contaminated soil, T. caerulescens accumulated higher Cd concentrations; but as T. praecox produced higher biomass, both species have similar ability to extract Cd.     

A potential bacterial biocontrol agent,strain S2V2 against pathogenic marine <Emphasis Type="Italic">Vibrio</Emphasis> in aquaculture

We isolated a marine bacterium strain S2V2 which inhibited the growth of pathogenic marine Vibrio spp. The aims of this research were to identify a new antibiotic-producing marine bacterium strain S2V2, and evaluate its spectrum activity and pathogenic property. Analysis of 16S rDNA sequence placed strain S2V2 in the genus Pseudoalteromonas, but the sequence similarity was low (95.46%) implying the strain might be a new species in this genus. Strain S2V2 inhibited the growth of 67.9% of 28 Vibrio strains tested. This strain inhibited V. alginolyticus, V. anguillarum, V. fluvialis, V. harveyi, V. metschnikovii, V. splendidus, V. ordalii, V. parahaemolyticus, and V. vulnificus, but inactive against V. campbellii, Aeromonas hydrophyla and Staphylococcus aureus. Strain S2V2 produced extracellular non proteinaceous antibacterial substances. The highest antibacterial activity was found when strain S2V2 was cultured for 96 h in ZoBell broth medium. An artificial infection to post larvae of Lithopenaeus vanname indicated that strain S2V2 was a non pathogenic bacterium. Non pathogenic property and specific antibacterial activity against a broad range of fish pathogenic marine Vibrio of strain S2V2 suggest that this strain is a prospective source of unique antibiotic and a potential biocontrol agent in marine aquaculture.