Biochemical, nutrient and inhibitory characteristics of Streptomyces cultured from a hypersaline estuary, the laguna Madre (Texas)

Streptomyces are common soil bacteria that produce secondary metabolites, including several antibiotics; however, the characteristics of marine Streptomyces are largely unknown. Sediment samples were taken from 3 sites in the Laguna Madre to isolate marine Streptomyces. Sediment was diluted, spread onto synthetic seawater media to estimate the total bacterial density of the samples and spread onto starch casein agar to isolate Streptomyces. Isolated Streptomyces were tested for salinity tolerance and optimal growth pH. Isolates were assayed using API 20E® test strips and BIOLOG™ plates to construct biochemical profiles and assess nutrient utilization abilities of the bacteria, respectively. Individual Streptomyces were tested for the ability to inhibit the growth of other isolated Streptomyces (i.e., interference competition) and putatively identified by DNA sequencing. Results showed that there was no significant difference in microbial density in sediments from the 3 sampling sites. Eleven (11) Streptomyces pure cultures were obtained in total; most tolerated salinity up to 60 ppt and grew optimally at pH 7.5. Biochemical profile comparisons showed that the Streptomyces were only at least 74% similar; most (8/11) were \u3e90% similar. Isolates could use between 87-95 carbon sources. Three (3) isolates displayed interference toward other isolates. Ten (10) isolates were identified as Streptomyces griseus by DNA sequencing. Laguna Madre Streptomyces organisms display some diverse characteristics with regards to their halotolerance, biochemical profiles, carbon source utilization and inhibition toward other organisms. Further investigations may yield greater understanding of these organisms in this and other marine environments and may be a reservoir of novel microorganisms and secondary metabolites

Involvement of TGFβ signaling pathway in oxidative stress and diabetic retinopathy

Diabetic Retinopathy (DR) is a leading cause of blindness in the U.S. However, not much is known of underlying molecular mechanism and how oxidative stress contributes to its development. In the present study, we investigated the involvement of TGFβ signaling pathway on the effect of oxidative stress on VEGF secretion and viability of retinal cells. VEGF is the hallmark that exacerbates DR progression in prolonged diabetes. Some major concerns that have arisen are the underlying effects of antioxidants in elevating VEGF secretion in diabetes. In this study, we evaluated how hypoxia (or low oxygen) impacts viability and VEGF secretion using 661W cone photoreceptor cells. Confluent 661W cells were grown in 5.5 mM normal or 30 mM high glucose, as well as subjected to CoCl2 to induce hypoxia. After treatment for 24 hours, conditioned media were collected for ELISA measurement to determine the amount of protein (VEGF) secretion. Viable cell numbers were also recorded. High glucose did not induce significant changes in viable cell number nor VEGF concentration in cell media. However, hypoxia condition resulted in a three-fold decrease in viable cell numbers and a three-fold increase in VEGF concentration. Furthermore, treatment with two TGFβ inhibitors: SMAD 3, SIS (or Inhibitor 1) and TGFβ receptor 1 kinase inhibitor (or Inhibitor 2) resulted in a reversal of hypoxia-induced changes. These results strongly suggest that TGFβ signaling pathway mediates hypoxia-induced retinal cell viability and VEGF secretion. Further translational research studies will provide evidence to identify appropriate and effective pharmaceutical targets in this molecular pathway to mitigate the development of DR

Opportunistic Pathogenic Bacteria Colonize Thorns of Native Rio Grande Valley Plants

Thorns serve as mechanical defenses of plants against herbivory. However, plant thorns harbor microorganisms that are potentially pathogenic. These pathogens may be transferred to herbivores and other animals and provide an additional defense for the plants. Thorns from 5 plant species native to the Rio Grande Valley of South Texas were collected and used to isolate bacteria colonizing the thorn surface. Thorns, leaves and stems of plants were visualized using Scanning Electron Microscopy (SEM) to observe any bacteria on the plant surface. Isolated bacteria were tested for their ability to grow in aerobic versus anaerobic environments, to produce hemolysis, carbon source utilization, and were gram-stained. Bacteria were identified by sequencing of the 16S rRNA gene. A total of 69 pure cultures were obtained of which 61 were positively identified. The majority of the bacteria were gram-positive and facultative (i.e., able to grow both aerobically and anaerobically). Many (23%) were hemolytic suggesting that they were opportunistic blood-borne pathogens. All isolated organisms metabolized a collection of 31 tested organic substrates and metabolic activity was observed to be more efficient among anaerobically-isolated microorganisms compared to microorganisms isolated aerobically. SEM revealed that bacteria were found on the thorn surface but also on the stems and leaves of the plants. Identification using the 16S rRNA gene revealed the presence of 10 species representing 7 genera. The most commonly identified organisms were Bacillus cereus, Serratia marcescens, and Pseudomonas aeruginosa, all of which are opportunistic pathogens

A Review on the Respiratory System Toxicity of Carbon Nanoparticles

The respiratory system represents the main gateway for nanoparticles’ entry into the human body. Although there is a myriad of engineered nanoparticles, carbon nanoparticles/nanotubes (CNPs/CNTs) have received much attention mainly due to their light weight, very high surface area, durability, and their diverse applications. Since their discovery and manufacture over two decades ago, much has been learned about nanoparticles’ interactions with diverse biological system models. In particular, the respiratory system has been of great interest because various natural and man-made fibrous particles are known to be responsible for chronic and debilitating lung diseases. In this review, we present up-to-date the literature regarding the effects of CNTs or carbon nanofibers (CNFs) on the human respiratory system with respect to respiratory toxicity pathways and associated pathologies. This article is intended to emphasize the potentially dangerous effects to the human respiratory system if inadequate measures are used in the manufacture, handling, and preparation and applications of CNP or CNP-based products. View Full-Tex

CHARACTERIZATION OF ARSENIC-TOLERANT BACTERIAL CULTURES FROM THE LOWER LAGUNA MADRE OF SOUTH TEXAS

Two forms of arsenic are found in the environment: As(V) and As(III), the latter being more toxic, water-soluble, and mobile. Microorganisms may increase the mobility of arsenic by reducing As(V) to As(III); however, detoxification and immobilization can occur via the oxidation of As(III) to As(V). The US EPA has set a minimum contaminant level of 10 parts per billion (ppb) for arsenic in drinking water. The research objective was to confirm the presence of arsenic-tolerant bacteria in the Lower Laguna Madre of south Texas. Sediment samples were collected and inoculated into growth media which contained either 2 mM As(III) or 2 mM As(V) to enrich for As(III)-tolerant and As(V)-tolerant bacteria, respectively. Twenty six (26) As (III)-tolerant and 12 As(V)-tolerant cultures were obtained. Most isolates were small white colonies of Gram-positive rods. Biochemical tests using commercially-made test strips showed that As(V)-tolerant isolates displayed greater resource usage compared to As(III)-tolerant isolates but overall, few cultures demonstrated a wide-range of biochemical capabilities. Isolates with distinct morphological and biochemical phenotypes were subjected to Polymerase Chain Reaction (PCR) amplification and sequencing of the 16S rRNA genes to identify the bacteria. Closest sequence matches were to the eubacterial genera Mycoplasma, Salinispora, Frankia, and Pelodictyon. These results suggest that the Lower Laguna Madre is inhabited by a diverse group of microorganisms able to tolerate toxic concentrations of different arsenic species

MANGANESE-REDUCING BACTERIAL COMMUNITIES FROM A HYPERSALINE ESTUARY IN SOUTH TEXAS UNDER CONDITIONS OF CHANGING SALINITY

Manganese reducing bacteria were quantified and enriched from sediments at two sites (ABC and LMT050) in the Laguna Madre of South Texas. Bacteria were tested for Mn(IV) reduction under different salinities. Denaturing gradient gel electrophoresis (DGGE) was used to profile bacterial communities from Mn(IV) saline enrichments. Results showed that the density of manganese reducing bacteria at ABC was 30X greater than LMT050. The ABC bacteria were able to reduce Mn(IV) at similar rates at different salinities; however, at LMT050, Mn(IV) reduction rates decreased at higher salinities. Three population genotypes were observed by DGGE. All were present and similarly abundant in LMT050 cultures at all salinities. In site ABC, one population was below detection at salt concentrations \u3c 60.0 ppt but observed at higher salt concentrations. We conclude that site ABC consists of a large manganese-reducing community that alters in structure when salinity changes, whereas site LMT050 contains a smaller but somewhat more adapted community

Chromium Tolerant Microbial Communities from the Chesapeake Bay Watershed

Chromium tolerant bacteria were enumerated from portions of the Chesapeake Bay watershed and examined for their potential to reduce Cr(VI). Water and sediment samples were collected from various locations in Baltimore Harbor and Bear Creek, as well as Sandy Point State Park in Maryland and the Anacostia River in Washington, DC. Samples were spread onto agar plates with CrO42- (5 ppm) as the sole terminal electron acceptor. Plates were incubated anaerobically and colony forming units (CFU) enumerated. CFU arising on minimal-CrO42- medium ranged from 103-104 mL-1 or g-1 and community estimates from sites in proximity to Baltimore City were approximately 6-30X higher than distal sites. Bacterial identification by BIOLOG™ or 16S rRNA sequencing indicated the presence of bacteria of the genera Klebsiella, Pseudomonas, Burkholderia, Kluyvera and others. Typical Cr(VI) reduction rates by these isolates were significantly lower than Shewanella oneidensis, a known metal-reducing bacterium. Results suggested that microbial communities in the Chesapeake Bay watershed, particularly in Baltimore Harbor and Bear Creek, had a high tolerance for Cr(VI) and/or could grow slowly with Cr(VI) as a terminal electron acceptor. However, the isolates did not rapidly degrade Cr(VI) in the laboratory

Phenotype harmonization and cross-study collaboration in GWAS consortia: the GENEVA experience

Genome-wide association study (GWAS) consortia and collaborations formed to detect genetic loci for common phenotypes or investigate gene-environment (G*E) interactions are increasingly common. While these consortia effectively increase sample size, phenotype heterogeneity across studies represents a major obstacle that limits successful identification of these associations. Investigators are faced with the challenge of how to harmonize previously collected phenotype data obtained using different data collection instruments which cover topics in varying degrees of detail and over diverse time frames. This process has not been described in detail. We describe here some of the strategies and pitfalls associated with combining phenotype data from varying studies. Using the Gene Environment Association Studies (GENEVA) multi-site GWAS consortium as an example, this paper provides an illustration to guide GWAS consortia through the process of phenotype harmonization and describes key issues that arise when sharing data across disparate studies. GENEVA is unusual in the diversity of disease endpoints and so the issues it faces as its participating studies share data will be informative for many collaborations. Phenotype harmonization requires identifying common phenotypes, determining the feasibility of cross-study analysis for each, preparing common definitions, and applying appropriate algorithms. Other issues to be considered include genotyping timeframes, coordination of parallel efforts by other collaborative groups, analytic approaches, and imputation of genotype data. GENEVA's harmonization efforts and policy of promoting data sharing and collaboration, not only within GENEVA but also with outside collaborations, can provide important guidance to ongoing and new consortia

The 2018 report of the Lancet Countdown on health and climate change: shaping the health of nations for centuries to come

The Lancet Countdown: tracking progress on health and climate change was established to provide an independent, global monitoring system dedicated to tracking the health dimensions of the impacts of, and the response to, climate change. The Lancet Countdown tracks 41 indicators across five domains: climate change impacts, exposures, and vulnerability; adaptation, planning, and resilience for health; mitigation actions and health co-benefits; finance and economics; and public and political engagement. This report is the product of a collaboration of 27 leading academic institutions, the UN, and intergovernmental agencies from every continent. The report draws on world-class expertise from climate scientists, ecologists, mathematicians, geographers, engineers, energy, food, livestock, and transport experts, economists, social and political scientists, public health professionals, and. doctors. The Lancet Countdown’s work builds on decades of research in this field, and was first proposed in the 2015 Lancet Commission on health and climate change,1 which documented the human impacts of climate change and provided ten global recommendations to respond to this public health emergency and secure the public health benefits available (panel 1)

Detectable Clonal Mosaicism from Birth to Old Age and its Relationship to Cancer

Clonal mosaicism for large chromosomal anomalies (duplications, deletions and uniparental disomy) was detected using SNP microarray data from over 50,000 subjects recruited for genome-wide association studies. This detection method requires a relatively high frequency of cells (>5–10%) with the same abnormal karyotype (presumably of clonal origin) in the presence of normal cells. The frequency of detectable clonal mosaicism in peripheral blood is low (<0.5%) from birth until 50 years of age, after which it rises rapidly to 2–3% in the elderly. Many of the mosaic anomalies are characteristic of those found in hematological cancers and identify common deleted regions that pinpoint the locations of genes previously associated with hematological cancers. Although only 3% of subjects with detectable clonal mosaicism had any record of hematological cancer prior to DNA sampling, those without a prior diagnosis have an estimated 10-fold higher risk of a subsequent hematological cancer (95% confidence interval = 6–18)