National Water Research Institute

Abstract Zoonotic diseases pose significant public health risks, with Salmonella being a major pathogen responsible for gastroenteritis, often transmitted through contaminated poultry products. Effective control of Salmonella in poultry is critical, but current methods face limitations due to the stealthy nature of the bacteria, which can persist in asymptomatic birds and spread during slaughter and processing. In this study, we investigated the potential of Nicotiana tabacum chloroplasts to produce TonB-dependent outer membrane transporters (TBDTs), including CirA, FepA, FhuA and IroN from Salmonella Enteritidis. These membrane proteins are critical for bacterial iron uptake and represent promising vaccine targets. Transplastomic tobacco plants successfully produced full-length recombinant CirA, FepA, and IroN proteins. Immunization of mice with chloroplast extracts containing these proteins elicited significant antibody responses, with statistical significance observed for CirA and FepA ( p < 0.05). Fluorescence microscopy demonstrated specific antibody binding to Salmonella cells, confirming immune recognition. These findings highlight the feasibility of using chloroplasts to produce complex bacterial membrane proteins and support the development of plant-based vaccines targeting iron acquisition systems to combat Salmonella infections in poultry.

It is always a challenge for a model developer to verify a three-dimensional hydrodynamic model, especially for the baroclinic term over variable topography, due to a lack of observational data sets or suitable analytical solutions. In this paper, exact solutions for the periodic forcing by surface heat flux and wind stress are given by solving the linearized equations of motion neglecting the rotation, advection and horizontal diffusion terms. The temperature at the bottom is set to a prescribed periodic value and a slip condition on flow is enforced at the bottom. The geometry of the quarter annulus, which has been extensively studied for two- and three-dimensional analytical solutions of unstratified water bodies, is used with a general power law variation of the bottom slope in the radial direction and is constant in the azimuthal direction. The analytical solutions are derived in a cylindrical coordinate system, which describes the three-dimensional fluid field in a Cartesian coordinate system. The results presented in this paper should provide a foundation for studying and verifying the baroclinic term over a varied topography in a three-dimensional numerical model.

Often it is implied that hydraulic particle separators that incorporate vortex technology provide enhanced particle settling. In this study, a generic vortex particle separator was closely examined using physical modeling to help understand typical flow hydraulic conditions. The study was conducted using particle capture analyses under different internal structure configurations, inflow rates, and inlet pipe configurations to examine how resulting changes to flow conditions influenced the settling of particles. The purpose of this study was not to evaluate performance or obtain absolute particle removal rates of a particular particle separator design; instead, the focus was on understanding how modifications to the flow conditions in the examined separator could affect the particle-settling efficiency. The comparison results show that the inflow-generated large internal vortex does not effectively improve particle settling; possible explanations are given based on hydraulics and physics principles. The study method and results can be extended to examine and improve other hydraulic particle separators.

This study shows the effect s of solid waste dumpsite on ground water quality in Farin-gida, Kaduna State Nigeria. Water samples were collected from six (6) different wells in three(3) strategic areas that have major dumpsites in Farin-gida. These samples were collected in November from both bore holes and hand dug wells within (0-50 meters) to the dumpsite. The following physico-chemical properties of well water was tested for, in the laboratory thus; Total Dissolve Solid, Total Alkalinity, Fluoride, PH, Turbidity and Electrical Conductivity. The results obtained as shown in table 1,2 and 3 respectively indicate that all the wells have varying levels of physico-chemical concentration that is different from the standard as recommended by World Health Organization (WHO) and Nigeria Standard for Drinking Water Quality (NSDWQ), which implies that the water from the study areas are not safe for drinking. Hence, should be treated.

Abstract This paper investigates the effectiveness of froth flotation to remove copper and other heavy metals from dredged anoxic sediments (<250 μm) using a lab scale flotation cell with a selected anionic collector. A sediment fraction selected for flotation tests was potentially contaminated with a copper concentration of about 1763 mg/kg. The sequential extraction study of sediments showed that copper was mainly incorporated, between 70%–85% in the sulfide-organic fraction. The mineralogical analysis of sediment particle by scanning electron microscopy identified that chalcopyrite was the predominant copper sulfide form in the sediments. Flotation tests under controlled, predetermined experimental conditions showed selective flotation removal of copper (70.4%) among other metals with less mass recovery (froth mass).

Climatic changes to freshwater ice in the Arctic are projected to produce a variety of effects on hydrologic, ecological, and socio-economic systems. Key hydrologic impacts include changes to low flows, lake evaporation regimes and water levels, and river-ice break-up severity and timing. The latter are of particular concern because of their effect on river geomorphology, vegetation, sediment and nutrient fluxes, and sustainment of riparian aquatic habitats. Changes in ice phenology will affect a wide range of related biological aspects of seasonality. Some changes are likely to be gradual, but others could be more abrupt as systems cross critical ecological thresholds. Transportation and hydroelectric production are two of the socio-economic sectors most vulnerable to change in freshwater-ice regimes. Ice roads will require expensive on-land replacements while hydroelectric operations will both benefit and be challenged. The ability to undertake some traditional harvesting methods will also be affected.

The distribution of an organism species in the environment deviates frequently from randomness due to natural cycles, availability of food resources and avoidance of harm. As a result, observed data can show over-dispersion, zero-inflation and even heavy tail. Models such as the negative binomial (NB), Poisson-inverse Gaussian (PIG), and zero-inflated Poisson are frequently used in applications instead of the Poisson distribution which is usually the default model. This paper uses a three-parameter discrete distribution that unifies distributions such as Poisson, NB, PIG, Neyman Type A, and Poisson-Pascal. The three-parameter family covers a wide range of tail heaviness relative to NB, and thus suitable for modelling over-dispersed count data with a shorter or longer tail. Moreover, it shows some capacity for zero-inflated data. Grouped counts of coliform bacteria from Lake Erie and counts of European corn borer larvae in field corn are used to illustrate the application of the model and the associated likelihood-based inferences. Copyright © 2010 John Wiley & Sons, Ltd.

Two amphipods, the hypogean Niphargus stygius and epigean Gammarus fossarum, were analyzed for fatty acid (FA) composition, electron transport system (ETS) activity and respiration (R) during a laboratory fasting experiment. In agreement with ETS and R measurements (and the ETS/R ratio), the hypogean N. stygius utilized FA more slowly than the epigean G. fossarum. Inter-specific differences in the utilization of certain FA during fasting were also revealed. While N. stygius tended to preserve all of its FA during the experimental fasting period, G. fossarum showed a tendency to utilize MUFA (monounsaturated FA) and SAFA (saturated FA) and preferentially retain PUFA (polyunsaturated FA). The significant correlations between ETS activity and composition of specific FA during fasting can be linked to R. During the fasting, both ETS activity and respiration rate of G. fossarum decreased, however, ETS/R ratio increased. In contrast, N. stygius did not show significant changes in these parameters. This is the first report, which connects ETS activity with changes in concentrations of specific FA during fasting. Such evolutionary adaptations of hypogean species enables them to better survive chronically low and/or discontinuous food supplies compared to epigean species, which live in environments where food shortages are much less frequent.

The present study was designed to develop a novel, rapid, direct DNA-based protocol to enumerate aeromonads in recreational waters. An Aeromonas genus-specific real-time quantitative polymerase chain reaction (Q-PCR) protocol was developed and optimized using newly designed genus-specific oligonucleotide primers derived from the gyrase B subunit (GyrB) gene. A standard curve was developed based on the PCR protocol with a minimum quantification limit of 10 cell equivalents ml(-1) achieved using an autoclaved water sample from recreational water spiked with known quantities of an Aeromonas ATCC strain. The Q-PCR protocol was validated and applied to detect and quantify the total number of aeromonads in water samples collected from two fresh water beaches on Lake Ontario. The Q-PCR protocol revealed significantly higher numbers of aeromonads in all water samples than a culture-based assay at both beaches. Foreshore sand was found to serve as a reservoir of high concentrations of Aeromonas similar to this phenomenon noted for enteric bacteria like Eschershia coli. The new real-time Q-PCR protocol facilitated the rapid quantification of total numbers of Aeromonas cells present in recreational water samples in <3 hours without culturing.