Physicochemical Characteristics and Microbial Quality of an Oil Polluted Site in Gokana, Rivers State.

Samples were collected from the soil surface area, the water surface, sub-surface sediment sand, sand from the river shore, Dead Sea food and dead mangrove vegetation leaves. Test results indicated that the Total Heterotrophic Bacteria (THB) values ranged from (9.0 ~ 103 . 2.6 ~ 106) cfu/ml with the sample from the water surface having the highest value (2.6 ~ 106) cfu/ml and the least with the sample from the sub-surface (9.0 ~103) cfu/g. The Total coliforms values ranged from (6.9 ~ 103 . 2.3 ~ 106) cfu/100g with sample from the dead vegetation leaves having the highest value (2.3 ~ 106) cfu/100g and the least value from the sample from mangrove substrate(6.9 ~ 103) cfu/100g. Among the physico-chemical parameters tested, TDS, lead, copper, chromium, cobalt, zinc, cadmium, nickel and arsenic were within acceptable limits as specified by regulatory agents. However, electrical conductivity, oil and grease, and iron were very high and above specified limits. The pH values ranged from 3.90 .8.15 with the sample from the mangrove substrate having the highest value (8.15) and the lowest value was from the sample from the crude on water surface (3.90). The electrical conductivity values ranged from (1275 . 3565) ƒÊS/cm with sample from crude band on soil surface having the highest value (3565)ƒÊS/cm and the lowest value from thesample from the sub-surface sediment sand (1275) ƒÊS/cm. The oil and grease values ranged from (620 . 32040) mg/kg with sample from soil surface having the highest value (32040) mg/kg and the lowest value from the river shore sand (620) mg/kg. The high level of oil and grease contamination poses a concern. This therefore, validates theconcern that releases of large quantities of oil to aquatic and terrestrial environments present a long term threat to all forms of lif

Evaluation of the Effect of Short-Term Cadmium Exposure on Brackish Water Shrimp-Palaemonetes africanus

This study evaluated the effect of short-term cadmium exposure on brackish water shrimp-Palaemonetes africanus. Tests were carried out by exposing the shrimps to the test solutions containing variousconcentrations of the cadmium (0, 0.1, 1.0, 4.0, 6.0, 8.0, 10.0, and 100.0) mg/l using the semi-static agitation test procedure. Mortality was recorded at 2, 4, 6, 8, 10, 12, 14 and 16 hours exposure periods. Test results indicated that the brackish water juvenile shrimp, Palaemonetes africanus were sensitive to the cadmium solution especially at concentration above 4.0mg/l. Though no death was recorded after 16hrs for 0.1mg/l, 1.0mg/l and 4.0mg/l respectively, however, for 6mg/l, 60% mortality was recorded after 4hrs and 100% after 8hrs, for 8mg/l, 20% mortality was recorded after 2hrs, 60% after 4hrs, 80% after 6hrs and 100% mortality after 8hrs respectively, for10mg/l, 40% mortality was recorded after 2hrs and 100% after 4hrs and 100% mortality was recorded for 100mg/l after 2hrs. The LC50 value calculated using Arithmetic Method of Karber was 5.0mg/l. It is therefore evident that the effects of acute toxicity of cadmium are concentration-related; the greater the concentration, the greater the effect

Determination of Selected Physicochemical Parameters and Heavy Metals in a Drilling Cutting Dump Site at Ezeogwu–Owaza, Nigeria.

The work was undertaken to determine some selected physicochemical parameters and heavy metals in a drilling cutting dump site. Test results indicated that some of the heavy metals like copper, iron andcalcium showed a high level of contamination in most of the plots under the study area. Iron had a value as high as 880mg/kg, copper 84mg/kg and calcium 12560mg/kg. These values were above target values as specified by the regulatory body, Department of Petroleum Resources (DPR). Moreover, the oil and grease indicated a high level of contamination, with a concentration of up to 840mg/kg in one of the plots. This was evident in lack of plant growth noticed in the study area as a result of depletion of NPK values below specified value by USDA Standards for plantgrowth. The high level of contamination of some of the physicochemical parameters and heavy metals as seen in this project underscores the need for due diligence in managing drilling cutting discharges from drilling  activitie

Ferredoxin containing bacteriocins suggest a novel mechanism of iron uptake in <i>Pectobacterium spp</i>

In order to kill competing strains of the same or closely related bacterial species, many bacteria produce potent narrow-spectrum protein antibiotics known as bacteriocins. Two sequenced strains of the phytopathogenic bacterium &lt;i&gt;Pectobacterium carotovorum&lt;/i&gt; carry genes encoding putative bacteriocins which have seemingly evolved through a recombination event to encode proteins containing an N-terminal domain with extensive similarity to a [2Fe-2S] plant ferredoxin and a C-terminal colicin M-like catalytic domain. In this work, we show that these genes encode active bacteriocins, pectocin M1 and M2, which target strains of &lt;i&gt;Pectobacterium carotovorum&lt;/i&gt; and &lt;i&gt;Pectobacterium atrosepticum&lt;/i&gt; with increased potency under iron limiting conditions. The activity of pectocin M1 and M2 can be inhibited by the addition of spinach ferredoxin, indicating that the ferredoxin domain of these proteins acts as a receptor binding domain. This effect is not observed with the mammalian ferredoxin protein adrenodoxin, indicating that &lt;i&gt;Pectobacterium spp.&lt;/i&gt; carries a specific receptor for plant ferredoxins and that these plant pathogens may acquire iron from the host through the uptake of ferredoxin. In further support of this hypothesis we show that the growth of strains of &lt;i&gt;Pectobacterium carotovorum&lt;/i&gt; and &lt;i&gt;atrosepticum&lt;/i&gt; that are not sensitive to the cytotoxic effects of pectocin M1 is enhanced in the presence of pectocin M1 and M2 under iron limiting conditions. A similar growth enhancement under iron limiting conditions is observed with spinach ferrodoxin, but not with adrenodoxin. Our data indicate that pectocin M1 and M2 have evolved to parasitise an existing iron uptake pathway by using a ferredoxin-containing receptor binding domain as a Trojan horse to gain entry into susceptible cells

Spatially Explicit Data: Stewardship and Ethical Challenges in Science

Scholarly communication is at an unprecedented turning point created in part by the increasing saliency of data stewardship and data sharing. Formal data management plans represent a new emphasis in research, enabling access to data at higher volumes and more quickly, and the potential for replication and augmentation of existing research. Data sharing has recently transformed the practice, scope, content, and applicability of research in several disciplines, in particular in relation to spatially specific data. This lends exciting potentiality, but the most effective ways in which to implement such changes, particularly for disciplines involving human subjects and other sensitive information, demand consideration. Data management plans, stewardship, and sharing, impart distinctive technical, sociological, and ethical challenges that remain to be adequately identified and remedied. Here, we consider these and propose potential solutions for their amelioration

Nanosize Titanium Dioxide Stimulates Reactive Oxygen Species in Brain Microglia and Damages Neurons in Vitro

BackgroundTitanium dioxide is a widely used nanomaterial whose photo-reactivity suggests that it could damage biological targets (e.g., brain) through oxidative stress (OS).ObjectivesBrain cultures of immortalized mouse microglia (BV2), rat dopaminergic (DA) neurons (N27), and primary cultures of embryonic rat striatum, were exposed to Degussa P25, a commercially available TiO2 nanomaterial. Physical properties of P25 were measured under conditions that paralleled biological measures.FindingsP25 rapidly aggregated in physiological buffer (800–1,900 nm; 25°C) and exposure media (~ 330 nm; 37°C), and maintained a negative zeta potential in both buffer (–12.2 ± 1.6 mV) and media (–9.1 ± 1.2 mV). BV2 microglia exposed to P25 (2.5–120 ppm) responded with an immediate and prolonged release of reactive oxygen species (ROS). Hoechst nuclear stain was reduced after 24-hr (≥100 ppm) and 48-hr (≥2.5 ppm) exposure. Microarray analysis on P25-exposed BV2 microglia indicated up-regulation of inflammatory, apoptotic, and cell cycling pathways and down-regulation of energy metabolism. P25 (2.5–120 ppm) stimulated increases of intracellular ATP and caspase 3/7 activity in isolated N27 neurons (24–48 hr) but did not produce cytotoxicity after 72-hr exposure. Primary cultures of rat striatum exposed to P25 (5 ppm) showed a reduction of immunohistochemically stained neurons and microscopic evidence of neuronal apoptosis after 6-hr exposure. These findings indicate that P25 stimulates ROS in BV2 microglia and is nontoxic to isolated N27 neurons. However, P25 rapidly damages neurons at low concentrations in complex brain cultures, plausibly though microglial generated ROS

Intraseasonal Dynamics and Dominant Sequences in H3N2 Influenza

Long-term influenza evolution has been well studied, but the patterns of sequence diversity within seasons are less clear. H3N2 influenza genomes sampled from New York State over ten years indicated intraseasonal changes in evolutionary dynamics. Using the mean Hamming distance of a set of amino acid or nucleotide sequences as an indicator of its diversity, we found that influenza sequence diversity was significantly higher during the early epidemic period than later in the influenza season. Diversity was lowest during the peak of the epidemic, most likely due to the high prevalence of a single dominant amino acid sequence or very few dominant sequences during the peak epidemic period, corresponding with rapid expansion of the viral population. The frequency and duration of dominant sequences varied by influenza protein, but all proteins had an abundance of one distinct sequence during the peak epidemic period. In New York State from 1995 to 2005, high sequence diversity during the early epidemic suggested that seasonal antigenic drift could have occurred primarily in this period, followed by a clonal expansion of typically one clade during the peak of the epidemic, possibly indicating a shift to neutral drift or purifying selection

Disinfection of football protective equipment using chlorine dioxide produced by the ICA TriNova system

<p>Abstract</p> <p>Backround</p> <p>Community-associated methicillin-resistant <it>Staphylococcus aureus </it>outbreaks have occurred in individuals engaged in athletic activities such as wrestling and football. Potential disease reduction interventions include the reduction or elimination of bacteria on common use items such as equipment. Chlorine dioxide has a long history of use as a disinfectant. The purpose of this investigation was to evaluate the ability of novel portable chlorine dioxide generation devices to eliminate bacteria contamination of helmets and pads used by individuals engaged in football.</p> <p>Methods</p> <p>In field studies, the number of bacteria associated with heavily used football helmets and shoulder pads was determined before and after overnight treatment with chlorine dioxide gas. Bacteria were recovered using cotton swabs and plated onto trypticase soy agar plates. In laboratory studies, <it>Staphylococcus aureus </it>was applied directly to pads. The penetration of bacteria into the pads was determined by inoculating agar plates with portions of the pads taken from the different layers of padding. The ability to eliminate bacteria on the pad surface and underlying foam layers after treatment with chlorine dioxide was also determined.</p> <p>Results</p> <p>Rates of recovery of bacteria after treatment clearly demonstrated that chlorine dioxide significantly (p < 0.001) reduce and eliminated bacteria found on the surface of pads. For example, the soft surface of shoulder pads from a university averaged 2.7 × 10³recoverable bacteria colonies before chlorine dioxide treatment and 1.3 × 10²recoverable colonies after treatment. In addition, the gas was capable of penetrating the mesh surface layer and killing bacteria in the underlying foam pad layers. Here, 7 × 10³to 4.5 × 10³laboratory applied <it>S. aureus </it>colonies were recovered from underlying layers before treatment and 0 colonies were present after treatment. Both naturally occurring bacteria and <it>S. aureus </it>were susceptible to the treatment process.</p> <p>Conclusion</p> <p>Results of this study have shown that chlorine dioxide can easily and safely be used to eliminate bacteria contamination of protective pads used by football players. This could serve to reduce exposure to potential pathogens such as the methicillin-resistant <it>Staphylococcus aureus </it>among this group of individuals.</p

BtubA-BtubB Heterodimer Is an Essential Intermediate in Protofilament Assembly

BACKGROUND:BtubA and BtubB are two tubulin-like genes found in the bacterium Prosthecobacter. Our work and a previous crystal structure suggest that BtubB corresponds to alpha-tubulin and BtubA to beta-tubulin. A 1:1 mixture of the two proteins assembles into tubulin-like protofilaments, which further aggregate into pairs and bundles. The proteins also form a BtubA/B heterodimer, which appears to be a repeating subunit in the protofilament. METHODOLOGY/PRINCIPAL FINDINGS:We have designed point mutations to disrupt the longitudinal interfaces bonding subunits into protofilaments. The mutants are in two classes, within dimers and between dimers. We have characterized one mutant of each class for BtubA and BtubB. When mixed 1:1 with a wild type partner, none of the mutants were capable of assembly. An excess of between-dimer mutants could depolymerize preformed wild type polymers, while within-dimer mutants had no activity. CONCLUSIONS:An essential first step in assembly of BtubA + BtubB is formation of a heterodimer. An excess of between-dimer mutants depolymerize wild type BtubA/B by sequestering the partner wild type subunit into inactive dimers. Within-dimer mutants cannot form dimers and have no activity

The U.S. Environmental Protection Agency Particulate Matter Health Effects Research Centers Program: a midcourse report of status, progress, and plans.

In 1998 Congress mandated expanded U.S. Environmental Protection Agency (U.S. EPA) health effects research on ambient air particulate matter (PM) and a National Research Council (NRC) committee to provide research oversight. The U.S. EPA currently supports intramural and extramural PM research, including five academically based PM centers. The PM centers in their first 2.5 years have initiated research directed at critical issues identified by the NRC committee, including collaborative activities, and sponsored scientific workshops in key research areas. Through these activities, there is a better understanding of PM health effects and scientific uncertainties. Future PM centers research will focus on long-term effects associated with chronic PM exposures. This report provides a synopsis of accomplishments to date, short-term goals (during the next 2.5 years) and longer-term goals. It consists of six sections: biological mechanisms, acute effects, chronic effects, dosimetry, exposure assessment, and the specific attributes of a coordinated PM centers program