An in vitro study of the photodynamic effect of rose bengal on trichophyton rubrum

Onychomycosis, a fungal infection of the finger or toenails, is predominantly caused by Trichophyton rubrum. Treatment is difficult due to high recurrence rates and problems with treatment compliance. For these reasons, alternative therapies are needed. Here we describe the photoactivation of Rose Bengal (RB) using a green laser (λ = 532 nm) at fluences of 68, 133 and 228 J/cm², and assess its fungicidal activity on T. rubrum spore suspensions. A 140 µM RB solution was able to induce a fungicidal effect on T. rubrum when photosensitized with the fluence of 228 J/cm². RB photosensitization using a green laser provides a potential novel treatment for T. rubrum infections. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Pseudo-nitzschia and domoic acid fluxes in Santa Barbara Basin (CA) from 1993 to 2008

Blooms of domoic acid (DA) producing Pseudo-nitzschia, regularly occur off the coast of California. Although it has been hypothesized that these blooms are increasing in frequency, the lack of historical records limits our understanding of potential causal mechanisms. In this study, an 15-year time-series (1993–2008) of sediment trap samples collected from the Santa Barbara Basin (SBB) at 540 m were analyzed for Pseudo-nitzschia (n = 196, microscopy and SEM) and DA (n = 206, LC–MS/MS) concentrations and fluxes. Results suggest that there was an abrupt shift towards greater frequency and higher magnitude Pseudo-nitzschia blooms and toxic DA flux events in the SBB after the year 2000. SEM analysis of sediment trap material indicates that these events were mainly blooms of P. australis, with cell fluxes increasing by an order of magnitude from a maximum of 4.5 × 10⁶ cells m⁻² d⁻¹ pre-2000, to as high as 3.2 × 10⁸ cells m⁻² d⁻¹ thereafter. Similarly, sediment trap DA fluxes increased by an average of 13.4 μg m⁻² d⁻¹, with only one large event (>5 μg m⁻² d⁻¹) from 1993 to 1999 versus 16 large DA events from 2000 to 2008. While the causes of this abrupt shift remain ambiguous, we suggest that this shift may be related to natural climate variability associated with a change in phase of the North Pacific Gyre Oscillation (NPGO) and its potential influence on the composition and magnitude of waters that are upwelled into the SBB.     

Testing small study effects in multivariate meta-analysis

Small study effects occur when smaller studies show different, often larger, treatment effects than large ones, which may threaten the validity of systematic reviews and meta-analyses. The most well-known reasons for small study effects include publication bias, outcome reporting bias, and clinical heterogeneity. Methods to account for small study effects in univariate meta-analysis have been extensively studied. However, detecting small study effects in a multivariate meta-analysis setting remains an untouched research area. One of the complications is that different types of selection processes can be involved in the reporting of multivariate outcomes. For example, some studies may be completely unpublished while others may selectively report multiple outcomes. In this paper, we propose a score test as an overall test of small study effects in multivariate meta-analysis. Two detailed case studies are given to demonstrate the advantage of the proposed test over various naive applications of univariate tests in practice. Through simulation studies, the proposed test is found to retain nominal Type I error rates with considerable power in moderate sample size settings. Finally, we also evaluate the concordance between the proposed tests with the naive application of univariate tests by evaluating 44 systematic reviews with multiple outcomes from the Cochrane Database.     

Epidemiology of Rhodococcus equi Strains on Thoroughbred Horse Farms

Pulsed-field gel electrophoresis of restriction endonuclease-digested genomic DNA from a large collection of clinical isolates of Rhodococcus equi, an important pathogen of foals, was used to compare strain distribution between farms and over time. Forty-four strains were found among 209 isolates, with 5 of these accounting for over half the isolates and the 22 strains isolated more than once accounting for 90% of the isolates. The average genotypic diversity on each farm and in each year was found to be less than the genotypic diversity of the isolates taken as a whole, with 5.2% of the total diversity being due to differences between farms and 5.5% to differences between years. A small number of strains on each farm were found to have caused at least half the clinical cases of disease, and these varied between farms and, to a lesser extent, years. Most strains were found on more than one farm, and some very similar restriction patterns were found among isolates from different continents, indicating that strains can be very widespread. Multiple strains were isolated in five of the six cases in which more than one isolate from a single foal was examined, indicating that disease may commonly be caused by simultaneous infection with multiple strains. It was concluded that there are a number of different strains of R. equi which carry the vapA gene, and these strains tend to be widespread, but individual farms tend to have particular strains associated with them.     

Recovery of phenotypically normal transgenic plants of Brassica oleracea upon Agrobacterium rhizogenes-mediated co-transformation and selection of transformed hairy roots by GUS assay

In this paper we describe the production of transgenic broccoli and cauliflower with normal phenotype using an Agrobacterium rhizogenes-mediated transformation system with efficient selection for transgenic hairy-roots. Hypocotyls were inoculated with Agrobacterium strain A4T harbouring the bacterial plasmid pRiA4 and a binary vector pMaspro::GUS whose T-DNA region carried the gus reporter gene. pRiA4 transfers T_L sequences carrying the rol genes that induce hairy root formation. Transgenic hairy-root production was increased in a difficult-to-transform cultivar by inclusion of 2,4-D in the medium used to resuspend the Agrobacterium prior to inoculation. Transgenic hairy roots could be selected from inoculated explants by screening root sections for GUS activity; this method eliminated the use of antibiotic resistance marker genes for selection. Transgenic hairy roots were produced from two cauliflower and four broccoli culivars. Shoots were regenerated from transgenic hairy root cultures of all four cultivars tested and successfully acclimatized to glasshouse conditions, although some plants had higher than diploid ploidy levels. Southern analysis confirmed the transgenic nature of these plants. T₀ plants from seven transgenic lines were crossed or selfed to produce viable seed. Genetic analysis of T₁ progeny confirmed the transmission of traits and revealed both independent and co-segregation of Ri T_L-DNA and vector T-DNA. GUS-positive phenotypically normal progeny free of T_L-DNA were identified in three transgenic lines out of the six tested representing all the cultivars regenerated including both cauliflower and broccoli.     

Thinner bark increases sensitivity of wetter Amazonian tropical forests to fire

Understory fires represent an accelerating threat to Amazonian tropical forests and can, during drought, affect larger areas than deforestation itself. These fires kill trees at rates varying from < 10 to c. 90% depending on fire intensity, forest disturbance history and tree functional traits. Here, we examine variation in bark thickness across the Amazon. Bark can protect trees from fires, but it is often assumed to be consistently thin across tropical forests. Here, we show that investment in bark varies, with thicker bark in dry forests and thinner in wetter forests. We also show that thinner bark translated into higher fire‐driven tree mortality in wetter forests, with between 0.67 and 5.86 gigatonnes CO₂ lost in Amazon understory fires between 2001 and 2010. Trait‐enabled global vegetation models that explicitly include variation in bark thickness are likely to improve the predictions of fire effects on carbon cycling in tropical forests.