Virulence traits in Cronobacter species isolated from different sources

Cronobacter spp. ( Enterobacter sakazakii ) includes gram-negative opportunistic foodborne pathogens known as rare but important causes of life-threatening neonatal infections. However, the pathogenic mechanism is not yet clear. In this study, 43 isolates of Cronobacter, from human and nonhuman sources, were analyzed. A total of four clusters were identified and 32 DNA pulsotypes were observed by pulsed-field gel electrophoresis. In addition, 86% of the Cronobacter isolates were able to adhere to HEp-2 cells and 35% were invasive, Cronobacter sakazakii isolates being the most efficient. Twenty-six percent of Cronobacter isolates were able to form biofilms, mainly those from nonhuman sources, such as Cronobacter dublinensis and Cronobacter malonaticus . Three putative virulence genes (siderophore-interacting protein (sip), type III hemolysin (hly), and plasminogen activator (cpa)) were identified by bioinformatic analysis and then detected by PCR. The sip gene was the most frequently detected (60%; 26/43), followed by the hly gene (37%; 16/43) and the cpa gene (28%; 12/43). The three genes were identified primarily in C. sakazakii. Our data show that Cronobacter species harbor different virulence traits.     

New baseline environmental assessment of mosquito ecology in northern Haiti during increased urbanization

The catastrophic 2010 earthquake in Port‐au‐Prince, Haiti, led to the large‐scale displacement of over 2.3 million people, resulting in rapid and unplanned urbanization in northern Haiti. This study evaluated the impact of this unplanned urbanization on mosquito ecology and vector‐borne diseases by assessing land use and change patterns. Land‐use classification and change detection were carried out on remotely sensed images of the area for 2010 and 2013. Change detection identified areas that went from agricultural, forest, or bare‐land pre‐earthquake to newly developed and urbanized areas post‐earthquake. Areas to be sampled for mosquito larvae were subsequently identified. Mosquito collections comprised five genera and ten species, with the most abundant species being Culex quinquefasciatus 35% (304/876), Aedes albopictus 27% (238/876), and Aedes aegypti 20% (174/876). All three species were more prevalent in urbanized and newly urbanized areas. Anopheles albimanus, the predominate malaria vector, accounted for less than 1% (8/876) of the collection. A set of spectral indices derived from the recently launched Landsat 8 satellite was used as covariates in a species distribution model. The indices were used to produce probability surfaces maps depicting the likelihood of presence of the three most abundant species within 30 m pixels. Our findings suggest that the rapid urbanization following the 2010 earthquake has increased the amount of area with suitable habitats for urban mosquitoes, likely influencing mosquito ecology and posing a major risk of introducing and establishing emerging vector‐borne diseases.     

Isolation and selection of native microorganisms for the aerobic treatment of simulated dairy wastewaters

Milk fat/protein degrading microorganisms were isolated from different locations of a dairy wastewater treatment system with the goal of developing an inoculum for bioaugmentation strategies. Eight isolates, identified by 16S rRNA gene sequence analysis as belonging to the genera Bacillus, Pseudomonas, and Acinetobacter, were tested for their ability to remove COD and protein from a milk-based medium (3000 mg/L COD) and compared to a commercial bioaugmentation inoculum. The Acinetobacter isolate exhibited a pellet-type growth in liquid culture, a property that could potentially aid in the separation of microbes and liquid phase following treatment. Based on the individual degradation capacity and growth behavior of the isolates, three microorganisms were further selected and tested together. This consortium exhibited a COD removal similar to the commercial inoculum (57% and 63%, respectively), but higher protein (consortium: 93%; commercial inoculum: 54%), and fat removals (consortium: 75%; commercial inoculum: 38%).     

Topical Formulations Containing Pimenta pseudocaryophyllus Extract: In Vitro Antioxidant Activity and In Vivo Efficacy Against UV-B-Induced Oxidative Stress

Pimenta pseudocaryophyllus is a Brazilian native plant that presents high concentrations of flavonoids and other polyphenolic compounds. Herein, we evaluated: (1) the chemical properties of P. pseudocaryophyllus ethanolic extract (PPE), (2) the in vitro antioxidant activity (AA) of PPE and of two different topical formulations (F1 and F2) containing PPE, (3) physico-chemical and functional stability, (4) in vitro release of PPE, and (5) in vivo capacity of formulations to prevent UV-B irradiation-induced skin damage. Results show that the polyphenol and flavonoid contents in PPE were 199.33 and 28.32 mg/g, respectively, and HPLC results show the presence of eugenol, tannic acid, and rutin. Evaluation of the in vitro AA of PPE demonstrated a dose-dependent effect and an IC₅₀ of 4.75 μg/mL in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3.0 μg/mL in 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The ferric-reducing antioxidant power (FRAP assay) was 0.046 μmol/L trolox equivalent/μg/mL of extract. Among the AA, only the capacity to scavenge DPPH radical of PPE was maintained in F1 and F2. In addition, both formulations satisfactorily released the extract. The evaluation of the functional stability of F1 and F2 did not demonstrate loss of activity by storage at room temperature and at 4°C/6 months. In irradiated mice, treatment with F1 and F2 added with PPE significantly increased the capacity to scavenge ABTS radical and the FRAP of skin compared to vehicle-treated mice. In conclusion, the present results suggest that formulations containing PPE may be a topical source of antioxidant compounds to decrease oxidative damages of the skin.     

PKCγ and PKCε are Differentially Activated and Modulate Neurotoxic Signaling Pathways During Oxygen Glucose Deprivation in Rat Cortical Slices

Neurochemical Research - Cerebral ischemia is known to trigger a series of intracellular events such as changes in metabolism, membrane function and intracellular transduction, which eventually...     

Megavariate data analysis of mass spectrometric proteomics data using latent variable projection method

There are many data mining techniques for processing and general learning of multivariate data. However, we believe the wavelet transformation and latent variable projection method are particularly useful for spectroscopic and chromatographic data. Projection based methods are designed to handle hugely multivariate nature of such data effectively. For the actual analysis of the data we have used latent variable projection methods such as principal component analysis (PCA) and partial least squares projection to latent structures based discriminant analysis (PLS-DA) to analyze the raw data presented to the participants of the First Duke Proteomics Data Mining Conference. PCA was used to solve problem #1 (clustering problem) and the PLS-DA was used to solve problem #2 (classification problem). The idea of internal and external cross-validation was used to validate the model obtained from the classification analysis. The simple two-component PLS-DA model obtained from the analysis performed well. The model has completely separated the two groups from all the data. The same model applied on two-thirds of the data showed good performance by external validation with independent test set of remaining 13 specimens obtained by setting aside the spectra of every third specimen (accuracy of 85%).     

‘Transient’ genetic suppression facilitates generation of hexose transporter null mutants in Leishmania mexicana

The genome of Leishmania mexicana encompasses a cluster of three glucose transporter genes designated LmxGT1, LmxGT2 and LmxGT3. Functional and genetic studies of a cluster null mutant (Δlmxgt1‐3) have dissected the roles of these proteins in Leishmania metabolism and virulence. However, null mutants were recovered at very low frequency, and comparative genome hybridizations revealed that Δlmxgt1‐3 mutants contained a linear extrachromosomal 40 kb amplification of a region on chromosome 29 not amplified in wild type parasites. These data suggested a model where this 29‐40k amplicon encoded a second site suppressor contributing to parasite survival in the absence of GT1‐3 function. To test this, we quantified the frequency of recovery of knockouts in the presence of individual overexpressed open reading frames covering the 29‐40k amplicon. The data mapped the suppressor activity to PIFTC3, encoding a component of the intraflagellar transport pathway. We discuss possible models by which PIFTC3 might act to facilitate loss of GTs specifically. Surprisingly, by plasmid segregation we showed that continued PIFTC3 overexpression was not required for Δlmxgt1‐3 viability. These studies provide the first evidence that genetic suppression can occur by providing critical biological functions transiently. This novel form of genetic suppression may extend to other genes, pathways and organisms.