Leaf vein fraction influences the Péclet effect and 18O enrichment in leaf water

The process of evaporation results in the fractionation of water isotopes such that the lighter ¹⁶O isotope preferentially escapes the gas phase leaving the heavier ¹⁸O isotope to accumulate at the sites of evaporation. This applies to transpiration from a leaf with the degree of fractionation dependent on a number of environmental and physiological factors that are well understood. Nevertheless, the ¹⁸O enrichment of bulk leaf water is often less than that predicted for the sites of evaporation. The advection of less enriched water in the transpiration stream has been suggested to limit the back diffusion of enriched evaporative site water (Péclet effect); however, evidence for this effect has been varied. In sampling across a range of species with different vein densities and saturated water contents, we demonstrate the importance of accounting for the relative ‘pool’ sizes of the vascular and mesophyll water for the interpretation of a Péclet effect. Further, we provide strong evidence for a Péclet signal within the xylem that if unaccounted for can lead to confounding of the estimated enrichment within the mesophyll water. This has important implications for understanding variation in the effective path length of the mesophyll and hence potentially the δ¹⁸O of organic matter.     

Crossing the threshold: an amphibian assemblage highly infected with Batrachochytrium dendrobatidis in the southern Brazilian Atlantic forest

The fungal infection caused by Batrachochytrium dendrobatidis (Bd) in amphibians is known to be lethal when infection intensity values exceed loads of 10,000 zoospores per individual. We investigated Bd infection intensity in 100 anurans of southern Brazil. Almost half of the individuals were infected and the intensity ranged from four to about 156,000 zoospore genomic equivalents. We found no clinical signs of chytridiomycosis and no evidence of mortality. However, we observed a reduction in the number of infected individuals with loads above 10,000 zoospores. This fact could be considered indirect evidence that individuals with high loads are removed from the population.     

Characterization of an anaerobic marine microbial community exposed to combined fluxes of perchlorate and salinity

Applied Microbiology and Biotechnology - The recent recognition of the environmental prevalence of perchlorate and its discovery on Mars, Earth’s moon, and in meteorites, in addition to its...     

Lemna minor tolerance to metal‐working fluid residues: implications for rhizoremediation

For the first time in the literature, duckweed (Lemna minor) tolerance (alone or in combination with a consortium of bacteria) to spent metal‐working fluid (MWF) was assessed, together with its capacity to reduce the chemical oxygen demand (COD) of this residue. In a preliminary study, L. minor response to pre‐treated MWF residue (ptMWF) and vacuum‐distilled MWF water (MWFw) was tested. Plants were able to grow in both residues at different COD levels tested (up to 2300 mg·l^?1), showing few toxicity symptoms (mainly growth inhibition). Plant response to MWFw was more regular and dose responsive than when exposed to ptMWF. Moreover, COD reduction was less significant in ptMWF. Thus, based on these preliminary results, a second study was conducted using MWFw to test the effectiveness of inoculation with a bacterial consortium isolated from a membrane bioreactor fed with the same residue. After 5 days of exposure, COD in solutions containing inoculated plants was significantly lower than in non‐inoculated ones. Moreover, inoculation reduced β+γ‐tocopherol levels in MWFw‐exposed plants, suggesting pollutant imposed stress was reduced. We therefore conclude from that L. minor is highly tolerant to spent MWF residues and that this species can be very useful, together with the appropriate bacterial consortium, in reducing COD of this residue under local legislation limits and thus minimise its potential environmental impact. Interestingly, the lipophilic antioxidant tocopherol (especially the sum of β+γ isomers) proved to be an effective plant biomarker of pollution.     

Unintended irradiation of internal mammary chain – Is that enough?

Aim

To evaluate the unintentional coverage of the internal mammary chain (IMC) with tangential fields irradiation to the breast, and its relation with the type of surgery employed.

Background

The dose distribution in regions adjacent to the treatment targets (mammary gland or chest wall), with incidental irradiation of the IMC, could translate into clinical benefit, due to the proximity of these regions.

Materials and methods

One hundred and twelve consecutive conformal radiotherapy plans were correlating the average dose to the IMC with the type of surgery employed, the extent of disease and the irradiation techniques.

Results

The mean doses to IMC after modified radical mastectomy (MRM), modified radical mastectomy with immediate reconstruction (MRM + R), and breast conservative surgery (BCS) were 30.34 Gy, 30.26 Gy, and 18.67 Gy, respectively. Significant differences were identified between patients who underwent MRM or MRM + R over BCS (p = 0.01 and 0.003, respectively), but not between MRM and MRM + R (p = 0.88). Mean doses to IMC were greater in patients with T3–T4 tumors when compared with more initial stages (≤T2) (p = 0.0096). The lymph node involvement also correlated with higher average doses to IMC (node positive: 26.1 Gy × node negative: 17.8 Gy, p = 0.0017).

Conclusions

The moderate dose level to the IMC in the unintentional irradiation scenario seems to be insufficient to treat the subclinical disease, although it could have an impact in patients undergoing mastectomy.     

Epistatic Gene-Based Interaction Analyses for Glaucoma in eMERGE and NEIGHBOR Consortium

Primary open angle glaucoma (POAG) is a complex disease and is one of the major leading causes of blindness worldwide. Genome-wide association studies have successfully identified several common variants associated with glaucoma; however, most of these variants only explain a small proportion of the genetic risk. Apart from the standard approach to identify main effects of variants across the genome, it is believed that gene-gene interactions can help elucidate part of the missing heritability by allowing for the test of interactions between genetic variants to mimic the complex nature of biology. To explain the etiology of glaucoma, we first performed a genome-wide association study (GWAS) on glaucoma case-control samples obtained from electronic medical records (EMR) to establish the utility of EMR data in detecting non-spurious and relevant associations; this analysis was aimed at confirming already known associations with glaucoma and validating the EMR derived glaucoma phenotype. Our findings from GWAS suggest consistent evidence of several known associations in POAG. We then performed an interaction analysis for variants found to be marginally associated with glaucoma (SNPs with main effect p-value <0.01) and observed interesting findings in the electronic MEdical Records and GEnomics Network (eMERGE) network dataset. Genes from the top epistatic interactions from eMERGE data (Likelihood Ratio Test i.e. LRT p-value <1e-05) were then tested for replication in the NEIGHBOR consortium dataset. To replicate our findings, we performed a gene-based SNP-SNP interaction analysis in NEIGHBOR and observed significant gene-gene interactions (p-value <0.001) among the top 17 gene-gene models identified in the discovery phase. Variants from gene-gene interaction analysis that we found to be associated with POAG explain 3.5% of additional genetic variance in eMERGE dataset above what is explained by the SNPs in genes that are replicated from previous GWAS studies (which was only 2.1% variance explained in eMERGE dataset); in the NEIGHBOR dataset, adding replicated SNPs from gene-gene interaction analysis explain 3.4% of total variance whereas GWAS SNPs alone explain only 2.8% of variance. Exploring gene-gene interactions may provide additional insights into many complex traits when explored in properly designed and powered association studies.     

Soil and entomopathogenic fungi with potential for biodegradation of insecticides: degradation of flubendiamide in vivo by fungi and in vitro by laccase

Purpose

Flubendiamide is a highly toxic and persistent insecticide that causes loss of insect muscle functions leading to paralysis and death. The objective was to screen for filamentous fungi in soils where insecticides had been applied, to isolate entomopathogenic fungi from insect larva (Anticarsia gemmatalis) that infest soybean crops, and to use these in biodegradation of insecticides.

Method

Filamentous fungi were isolated from soils, and growth inhibition was evaluated on solid medium containing commercial insecticides, Belt® (flubendiamide) and Actara® (thiamethoxam). A total of 133 fungi were isolated from soil and 80 entomopathogenic fungi from insect larva. Based on growth inhibition tests, ten soil fungi, 2 entomopathogenic fungi, and Botryosphaeria rhodina MAMB-05 (reference standard) were selected for growth on commercial insecticides in solid media. Fungi were grown in submerged fermentation on media containing commercial insecticides and assayed for laccase activity.

Result

Isolates JUSOLCL039 (soil), JUANT070 (insect), and MAMB-05 performed best, and were respectively inhibited by 48.41%, 75.97%, and 79.23% when cultivated on 35 g/L Actara®, and 0.0, 5.42%, and 43.39% on 39.04 g/L Belt®. JUSOLCL039 and JUANT070 were molecularly identified as Trichoderma koningiopsis and Neurospora sp., respectively. The three fungal isolates produced laccase constitutively, albeit at low activities. Fungal growth on pure flubendiamide and thiamethoxam resulted in only thiamethoxam inducing high laccase titers (10.16 U/mL) by JUANT070. Neurospora sp. and B. rhodina degraded flubendiamide by 27.4% and 9.5% in vivo, while a crude laccase from B. rhodina degraded flubendiamide by 20.2% in vitro.

Conclusion

This is the first report of fungi capable of degrading flubendiamide, which have applications in bioremediation.

     

Evaluation of monocyte subsets and markers of activation in leprosy reactions

Understanding host immune pathways associated with tissue damage during reactions are of upmost importance to the development of immune intervention strategies. The participation of monocytes in leprosy reactions was evaluated by determining the frequency of monocyte subsets and the degree of cellular activation through the expression of MHCII and the co-stimulatory molecules CD40, CD80, CD86. Leprosy subjects with or without reactions were included in this cross-sectional study. Peripheral blood mononuclear cell were isolated and stained ex vivo to determine monocyte subsets and the degree of cellular activation by flow cytometry. Intermediate monocytes were increased in leprosy patients with reactions when compared to patients without reactions. Although no difference was detected in the frequency of monocyte subsets between type 1 and 2 reactions, the expression of CD80 was increased in monocytes from patients with type 1 reactions and CD40 was higher in paucibacillary subjects presenting type 1 reactions. Moreover, CD86 and MHC II expression were higher in intermediate monocytes when compared to the other subsets in leprosy reaction types 1 and 2. Intermediate monocyte activation with CD86 and MHCII expression is involved with both type 1 and 2 reactions, whereas CD80 and CD40 expression is related to type 1 reactions.