Distribution of indicator bacteria and Vibrio parahaemolyticus in sewage-polluted intertidal sediments

The impact of a sewage point source on the bacterial densities in an intertidal mud flat in Boston Harbor, Mass., was investigated. The area, Savin Hill Cove, acts as a receiving basin for a combined storm and sewage outlet (CSO). Preliminary examination of sediments and overlying water at high tide demonstrated that fecal coliforms were present in sediments at abundances 2 to 4 orders of magnitude higher than in the overlying water column. The following bacterial counts were determined from sediments along a sampling transect extending 460 m from the CSO: total bacteria by epifluorescent microscopy, heterotrophic bacteria by plate counts on nutrient-rich and nutrient-poor media, fecal coliforms and enterococci by membrane filtration, and Vibrio parahaemolyticus by a most-probable-number technique with a resuscitation step. Median sediment grain size, average tidal exposure, carbon/nitrogen ratio, and total organic carbon were also measured. All bacterial indices, except for V. parahaemolyticus, declined significantly with distance from the outfall. Multiple regression analysis indicated that tidal exposure (low tides) may affect densities of total bacteria. Fecal coliforms and enterococci were still present in appreciable numbers in sediments as far as 460 m away from the CSO. In contrast, V. parahaemolyticus densities did not correlate with the other bacterial counts nor with any of the environmental parameters examined. These results indicate that intertidal sediments which adjoin point sources of pollution are severely contaminated and should be considered as potentially hazardous reservoirs of sewage-borne diseases.     

Phenanthrene mineralization along a natural salinity gradient in an Urban Estuary,Boston Harbor,Massachusetts

The effect of varying salinity on phenanthrene and glutamate mineralization was examined in sediments along a natural salinity gradient in an urban tidal river. Mineralization was measured by trapping¹⁴CO₂ from sediment slurries dosed with trace levels of [¹⁴C]phenanthrene or [¹⁴C]glutamate. Sediments from three sites representing three salinity regimes (0, 15, and 30%.) were mixed with filtered column water from each site. Ambient phenanthrene concentrations were also determined to calculate phenanthrene mineralization rates. Rates of phenanthrene mineralization related significantly to increasing salinity along the transect as determined by linear regression analysis. Rates ranged from 1 ng/hour/g dry sediment at the freshwater site to > 16 ng/hour/g dry sediment at the 30 salinity site. Glutamate mineralization also increased from the freshwater to the marine site; however, the relationship to salinity was not statistically significant.To examine the effect of salinity on mineralizing activities, individual sediments were mixed with filtered water of the other two sites. Slurries were also made with artificial seawater composed of 0, 15, or 30 g NaCl/ liter to substitute for overlying water. Rates of phenanthrene mineralization in the 0 ambient salinity sediments were not affected by higher salinity waters. Activities in the 15 and 30 ambient salinity sediments, however, were significantly inhibited by incubation with 0 salinity water. The inhibition, in large part, appears to be due to the decreased NaCl concentration of the water phase. Glutamate mineralization was affected in a similar manner, but not as dramatically as phenanthrene mineralization. The results suggest that phenanthrene degraders in low salinity estuarine sediments subject to salt water intrusion are tolerant to a wide range of salinities but phenanthrene degradation in brackish waters is mainly a function of obligate marine microorganisms.     

Seasonal Biotransformation of Naphthalene, Phenanthrene, and Benzo[a]pyrene in Surficial Estuarine Sediments

Transformation rates of naphthalene, phenanthrene, and benzo[a]pyrene in oxidized surficial sediments of a polluted urban estuary, Boston Harbor, Mass., were determined over a period of 15 months. Three sites characterized by muddy sediments were selected to represent a >300-fold range of ambient polycyclic aromatic hydrocarbon (PAH) concentration. Transformation rates were determined by a trace-level radiolabel PAH assay which accounted for PAH mineralization, the formation of polar metabolites, residue, and recovered parental PAHs in sediment slurries. Transformation rates of the model PAHs increased with increasing ambient PAH concentrations. However, turnover times for a given PAH were similar at all sites. The turnover times were as follows: naphthalene, 13.2 to 20.1 days; phenanthrene, 7.9 to 19.8 days, and benzo[a]pyrene, 53.7 to 82.3 days. At specific sites, rates were significantly affected by salinity, occasionally affected by temperature, but not affected by pH over the course of the study. Seasonal patterns of mineralization were observed for each of the PAHs at all sites. The timing of seasonal maxima of PAH mineralization varied from site to site. Seasonal potential heterotrophic activities as measured by acetate and glutamate mineralization rates did not always coincide with PAH mineralization maxima and minima, suggesting that the two processes are uncoupled in estuarine sediments.     

Monocarbonyl Analogs of Curcumin with Potential to Treat Colorectal Cancer

Curcumin has a plethora of biological properties, making this compound potentially effective in the treatment of several diseases, including cancer. However, curcumin clinical use is compromised by its poor pharmacokinetics, being crucial to find novel analogs with better pharmacokinetic and pharmacological properties. Here, we aimed to evaluate the stability, bioavailability and pharmacokinetic profiles of monocarbonyl analogs of curcumin. A small library of monocarbonyl analogs of curcumin 1a–q was synthesized. Lipophilicity and stability in physiological conditions were both assessed by HPLC-UV, while two different methods assessed the electrophilic character of each compound monitored by NMR and by UV-spectroscopy. The potential therapeutic effect of the analogs 1a–q was evaluated in human colon carcinoma cells and toxicity in immortalized hepatocytes. Our results showed that the curcumin analog 1e is a promising agent against colorectal cancer, with improved stability and efficacy/safety profile.     

Comparative effects of Aroclor 1254 (polychlorinated biphenyls) and phenanthrene on glucose uptake by freshwater microbial populations.

The effects of polychlorinated biphenyl (PCB) and phenanthrene stress on glucose uptake by natural microbial populations were examined by the heterotrophic potential technique. Temporal and spatial distributions in glucose uptake velocities were examined for natural samples as well as PCB- and phenanthrene-stressed samples. Statistical analysis indicated significant variability among the various samples. It was demonstrated that the environmental variables contributed significantly to the variability in uptake kinetics. Although general trends indicated a PCB-induced stimulation in uptake velocities, these trends were in part masked by sample variability. Data analysis indicated no statistically significant PCB or phenanthrene effect on either total glucose uptake velocities or the proportion of 14CO2 evolved, as compared to natural unstressed samples.     

Comparative effects of Aroclor 1254 (polychlorinated biphenyls) and phenanthrene on glucose uptake by freshwater microbial populations.

The effects of polychlorinated biphenyl (PCB) and phenanthrene stress on glucose uptake by natural microbial populations were examined by the heterotrophic potential technique. Temporal and spatial distributions in glucose uptake velocities were examined for natural samples as well as PCB- and phenanthrene-stressed samples. Statistical analysis indicated significant variability among the various samples. It was demonstrated that the environmental variables contributed significantly to the variability in uptake kinetics. Although general trends indicated a PCB-induced stimulation in uptake velocities, these trends were in part masked by sample variability. Data analysis indicated no statistically significant PCB or phenanthrene effect on either total glucose uptake velocities or the proportion of 14CO2 evolved, as compared to natural unstressed samples.     

The promoter of filamentation (POF1) protein from <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> is an ATPase involved in the protein quality control process

Background

The gene YCL047C, which has been renamed promoter of filamentation gene (POF1), has recently been described as a cell component involved in yeast filamentous growth. The objective of this work is to understand the molecular and biological function of this gene.

Results

Here, we report that the protein encoded by the POF1 gene, Pof1p, is an ATPase that may be part of the Saccharomyces cerevisiae protein quality control pathway. According to the results, Δpof1 cells showed increased sensitivity to hydrogen peroxide, tert-butyl hydroperoxide, heat shock and protein unfolding agents, such as dithiothreitol and tunicamycin. Besides, the overexpression of POF1 suppressed the sensitivity of Δpct1, a strain that lacks a gene that encodes a phosphocholine cytidylyltransferase, to heat shock. In vitro analysis showed, however, that the purified Pof1p enzyme had no cytidylyltransferase activity but does have ATPase activity, with catalytic efficiency comparable to other ATPases involved in endoplasmic reticulum-associated degradation of proteins (ERAD). Supporting these findings, co-immunoprecipitation experiments showed a physical interaction between Pof1p and Ubc7p (an ubiquitin conjugating enzyme) in vivo.

Conclusions

Taken together, the results strongly suggest that the biological function of Pof1p is related to the regulation of protein degradation.

     

Treatment with apolipoprotein A-1 mimetic peptide reduces lupus-like manifestations in a murine lupus model of accelerated atherosclerosis

Introduction

The purpose of this study was to evaluate the effects of L-4F, an apolipoprotein A-1 mimetic peptide, alone or with pravastatin, in apoE^-/-Fas^-/-C57BL/6 mice that spontaneously develop immunoglobulin G (IgG) autoantibodies, glomerulonephritis, osteopenia, and atherosclerotic lesions on a normal chow diet.

Methods

Female mice, starting at eight to nine weeks of age, were treated for 27 weeks with 1) pravastatin, 2) L-4F, 3) L-4F plus pravastatin, or 4) vehicle control, followed by disease phenotype assessment.

Results

In preliminary studies, dysfunctional, proinflammatory high-density lipoproteins (piHDL) were decreased six hours after a single L-4F, but not scrambled L-4F, injection in eight- to nine-week old mice. After 35 weeks, L-4F-treated mice, in the absence/presence of pravastatin, had significantly smaller lymph nodes and glomerular tufts (P_{L, LP} < 0.05), lower serum levels of IgG antibodies to double stranded DNA (dsDNA) (P_L < 0.05) and oxidized phospholipids (oxPLs) (P_{L, LP} < 0.005), and elevated total and vertebral bone mineral density (P_{L, LP} < 0.01) compared to vehicle controls. Although all treatment groups presented larger aortic root lesions compared to vehicle controls, enlarged atheromas in combination treatment mice had significantly less infiltrated CD68⁺ macrophages (P_LP < 0.01), significantly increased mean α-actin stained area (P_LP < 0.05), and significantly lower levels of circulating markers for atherosclerosis progression, CCL19 (P_{L, LP} < 0.0005) and VCAM-1 (P_L < 0.0002).

Conclusions

L-4F treatment, alone or with pravastatin, significantly reduced IgG anti-dsDNA and IgG anti-oxPLs, proteinuria, glomerulonephritis, and osteopenia in a murine lupus model of accelerated atherosclerosis. Despite enlarged aortic lesions, increased smooth muscle content, decreased macrophage infiltration, and decreased pro-atherogenic chemokines in L-4F plus pravastatin treated mice suggest protective mechanisms not only on lupus-like disease, but also on potential plaque remodeling in a murine model of systemic lupus erythematosus (SLE) and accelerated atherosclerosis.     

Economic evaluation of water loss saving due to the biological control of water hyacinth at New Year’s Dam,Eastern Cape province,South Africa

Water hyacinth Eichhornia crassipes is considered the most damaging aquatic weed in the world. However, few studies have quantified the impact of this weed economically and ecologically, and even fewer studies have quantified the benefits of its control. This paper focuses on water loss saving as the benefit derived from biological control of this plant between 1990 and 2013 at New Year’s Dam, Alicedale, Eastern Cape, South Africa. Estimates of water loss due to evapotranspiration from water hyacinth vary significantly; therefore, the study used three different rates, high, medium and low. A conservative raw agriculture value of R 0.26 per m³ was used to calculate the benefits derived by the water saved. The present benefit and cost values were determined using 10% and 5% discount rates. The benefit/cost ratio at the low evapotranspiration rate was less than one, implying that biological control was not economically viable but, at the higher evapotranspiration rates, the return justified the costs of biological control. However, at the marginal value product of water, the inclusion of the costs of damage to infrastructure, or the adverse effects of water hyacinth on biodiversity, would justify the use of biological control, even at the low transpiration rate.     

The abundance of an invasive freshwater snail Tarebia granifera (Lamarck, 1822) in the Nseleni River,South Africa

The invasive freshwater snail Tarebia granifera (Lamarck, 1822) was first reported in South Africa in 1999 and it has become widespread across the country, with some evidence to suggest that it reduces benthic macroinvertebrate biodiversity. The current study aimed to identify the primary abiotic drivers behind abundance patterns of T. granifera, by comparing the current abundance of the snail in three different regions, and at three depths, of the highly modified Nseleni River in KwaZulu-Natal, South Africa. Tarebia granifera was well established throughout the Nseleni River system, with an overall preference for shallow waters and seasonal temporal patterns of abundance. Although it is uncertain what the ecological impacts of the snail in this system are, its high abundances suggest that it should be controlled where possible and prevented from invading other systems in the region.