Cerium Oxide Nanoparticles Attenuate Oxidative Stress and Inflammation in the Liver of Diethylnitrosamine-Treated Mice

Biological Trace Element Research - The catalytic activity of cerium oxide nanoparticles (CeO2NPs) is responsible for its application as an antitumor agent. This activity may be due to its ability...     

THE EFFECT OF pH ON THE DIVISION RATE OF THE COCCOLITHOPHORID CRICOSPHAERA ELONGATA1

The division rate of Cricosphaera elongata was measured as a function of pH in a medium buffered with the CO₂-bicarbonate-carbonate system. The optimum pH for cell division of the coccolithophorid was 7.8. A change of the partial pressure of CO₂ in the medium from 0.03 to 5% did not affect the division rate. Between pH 6.4 and 7.8 changes in the bicarbonate concentration from 0.1 to 6.0 mm and carbonate concentration from 0.007 to 0.1 mm did not affect the rate of division. At loiv experimental pH, C. elongata was nonmotile and grew in clumps; at higher pH values, it was motile and solitary. Coccoliths were not found covering C. elongata if calcite was soluble in the medium.     

Coliform Behavior in Frozen Foods: I. Rapid Test for the Recovery of Escherichia coli from Frozen Foods

An assortment of 496 samples of frozen foods consisting of fish or marine products, variety types, and cream pie desserts were subjected to four parallel examinations for the recovery of Escherichia coli. The test procedures consisted of two low-temperature (35 C) and two high-temperature (44 C) presumptive tests, followed by an E C confirmatory test at 45.5 C. Of all the test methods examined, a single Lauryl Sulfate Tryptose (LST) presumptive test at 44 C gave best E. coli recovery (425). This recovery compared favorably with the lengthier Association of Official Analytical Chemists test with which only 420 E. coli cells were recovered. The LST (44 C) test saves much time, since it renders a follow-up 48-hr confirmatory test unnecessary. Moreover, since 96% of all the E. coli are recovered within 24 hr by LST (44 C), it is essentially a 24-hr test. The results of this study also confirmed earlier findings, in that it is possible to describe a specific coliform bacteriological test method by simple reproducible productivity ratios. E. coli recovery dilution data and coliform group behavior were also examined.     

BIOLUMINESCENCE AND CHLOROPLAST MOVEMENT IN THE DINOFLAGELLATE PYROCYSTIS LUNULA1

The lunate cysts of Pyrocystis lunula have a bioluminescent emission spectrum with a peak intensity of 477.5 ± 1 mμ. The light originates from the protoplasm in the center of the cysts. Six to eight hr after the cysts were placed in the dark, they produced 300 to 800 times more luminescence than controls maintained under constant, illumination. Plastids contract distally when the cysts are placed in the dark. If kept in the dark, the plastids contract distally and expand with a circadian rhythm persisting several days. At intensities of 2200 μm cm-’or less, the plastids are expanded. The plastids are contracted into the central area of the cysts at light intensities of 4000 μw cm-² and above. The Gymnodinium stage of the life cycle is not bioluminescent.     

Population-Level Density Dependence Influences the Origin and Maintenance of Parental Care

Parental care is a defining feature of animal breeding systems. We now know that both basic life-history characteristics and ecological factors influence the evolution of care. However, relatively little is known about how these factors interact to influence the origin and maintenance of care. Here, we expand upon previous work and explore the relationship between basic life-history characteristics (stage-specific rates of mortality and maturation) and the fitness benefits associated with the origin and the maintenance of parental care for two broad ecological scenarios: the scenario in which egg survival is density dependent and the case in which adult survival is density dependent. Our findings suggest that high offspring need is likely critical in driving the origin, but not the maintenance, of parental care regardless of whether density dependence acts on egg or adult survival. In general, parental care is more likely to result in greater fitness benefits when baseline adult mortality is low if 1) egg survival is density dependent or 2) adult mortality is density dependent and mutant density is relatively high. When density dependence acts on egg mortality, low rates of egg maturation and high egg densities are less likely to lead to strong fitness benefits of care. However, when density dependence acts on adult mortality, high levels of egg maturation and increasing adult densities are less likely to maintain care. Juvenile survival has relatively little, if any, effect on the origin and maintenance of egg-only care. More generally, our results suggest that the evolution of parental care will be influenced by an organism’s entire life history characteristics, the stage at which density dependence acts, and whether care is originating or being maintained.     

Integrated assessment of the heavy metal pollution status and potential ecological risk in the Lagos Lagoon,South West,Nigeria

This study was carried out to assess the heavy metal pollution status and potential ecological risk in the Lagos lagoon, Nigeria. The concentrations of twelve heavy metals commonly associated with environmental pollution were determined in the sediments of the lagoon by Atomic Absorption Spectrophotometry (AAS) and the cold vapor method was employed for Mercury (Hg). Nonempirical risk indices and empirical Sediment Quality Guidelines (SQGs) were used to assess the ecological risk associated with heavy metal in the sediments. The nonempirical risk indices showed that Hg, Arsenic (As), and Cadmium (Cd) are the major contributors to the ecological risk associated with heavy metal pollution in the ecosystem. Comparison of heavy metal concentrations to the Screening Quick Reference Table (SQuiRT) showed that mean concentration of Cd (5.22 and 4.88 mg kg^?1 in dry and rainy seasons, respectively) exceeds the effect range low (ERL) value (1.20 mg kg^?1) in effect to biota. Industries sited around the lagoon have effluent output points in the lagoon serving as a major source of heavy metals coupled with indirect discharges from other sources. Heavy metals are nonbiodegradable, toxic and have the potential to alter ecosystem health, thus pollution sources should be effectively monitored and contained.     

Variation in gut microbial communities and its association with pathogen infection in wild bumble bees (Bombus)

Bacterial gut symbiont communities are critical for the health of many insect species. However, little is known about how microbial communities vary among host species or how they respond to anthropogenic disturbances. Bacterial communities that differ in richness or composition may vary in their ability to provide nutrients or defenses. We used deep sequencing to investigate gut microbiota of three species in the genus Bombus (bumble bees). Bombus are among the most economically and ecologically important non-managed pollinators. Some species have experienced dramatic declines, probably due to pathogens and land-use change. We examined variation within and across bee species and between semi-natural and conventional agricultural habitats. We categorized as ‘core bacteria'' any operational taxonomic units (OTUs) with closest hits to sequences previously found exclusively or primarily in the guts of honey bees and bumble bees (genera Apis and Bombus). Microbial community composition differed among bee species. Richness, defined as number of bacterial OTUs, was highest for B. bimaculatus and B. impatiens. For B. bimaculatus, this was due to high richness of non-core bacteria. We found little effect of habitat on microbial communities. Richness of non-core bacteria was negatively associated with bacterial abundance in individual bees, possibly due to deeper sampling of non-core bacteria in bees with low populations of core bacteria. Infection by the gut parasite Crithidia was negatively associated with abundance of the core bacterium Gilliamella and positively associated with richness of non-core bacteria. Our results indicate that Bombus species have distinctive gut communities, and community-level variation is associated with pathogen infection.     

Indiscelio: A new genus of Scelionidae (Platygastroidea) from India

A new scelionine genus Indiscelio Veenakumari, Popovici and Talamas is described from India with type species Indiscelio aulon Veenakumari, Popovici and Talamas. Both sexes are described and imaged. Affinities with morphologically similar genera are discussed.