Neonatal overnutrition programming impairs cholecystokinin effects in adultmale rats.

Overfeeding and rapid weight gain during early life are risk factors for the development of obesity in adulthood. This metabolic malprogramming may be mediated by endocrine disturbances during critical periods of development. Cholecystokinin (CCK) acts on the central nervous system by elevating thermogenesis and the activity of anorectic neurons, modulating overall energy balance. Therefore, we tested the hypothesis that postnatal overfeeding impaired CCK effects. Pups were raised in either a litter of three (neonatal overnutrition/small litter group) or 12 (controls/normal litter group) pups per dam to study the effects of postnatal overfeeding on the central and peripheral CCK systems in adulthood. Rats raised in small litters became overweight during lactation and remained overweight as adults, with increased adiposity and plasma levels of lipids, glucose, insulin, and leptin. Neonatally over-nourished rats showed attenuation of gastric emptying and anorexigenic response to CCK, suggesting that offspring from the SL group may present CCK resistance as adult male rats. Consistent with this idea, overweight rats displayed impaired central response in c-Fos immunoreactivity on the nucleus tractus solitarius, area postrema, paraventricular nucleus, central amygdala, arcuate nucleus, and dorsomedial hypothalamus in response to peripheral CCK at adulthood. The small litter group of adult male rats also exhibited reduced norepinephrine- and CCK-stimulated thermogenesis. Unresponsiveness to the effects of CCK may contribute to overweight and metabolic dysfunctions observed in postnatally over-nourished adult rats. Thus, the involvement of an impaired CCK system, among other neurohormonal failures, may contribute to the development of obesity.

Bacterial diversity in oil-polluted marine coastal sediments.

Marine environments harbour a persistent microbial seed which can be shaped by changes of the environmental conditions such as contamination by petroleum components. Oil spills, together with small but continuous discharges of oil from transportation and recreational activities, are important sources of hydrocarbon pollution within the marine realm. Consequently, prokaryotic communities have become well pre-adapted toward oil pollution, and many microorganisms that are exposed to its presence develop an active degradative response. The natural attenuation of oil pollutants, as has been demonstrated in many sites, is modulated according to the intrinsic environmental properties such as the availability of terminal electron acceptors and elemental nutrients, together with the degree of pollution and the type of hydrocarbon fractions present. Whilst dynamics in the bacterial communities in the aerobic zones of coastal sediments are well characterized and the key players in hydrocarbon biodegradation have been identified, the subtidal ecology of the anaerobic community is still not well understood. However, current data suggest common patterns of response in these ecosystems.

Sickness behavior is accentuated in rats with metabolic disorders induced by a fructose diet.

This study investigated behavioral responses to an immune challenge among animals with fructose-induced metabolic disorders. Adult male Wistar rats were provided either water or a fructose solution (10%) for 5 weeks. Sickness behaviors were assessed 2h following the injection of either a lipopolysaccharide (LPS) or vehicle. The rats were subjected to an open field test, a social interaction test, a food intake test and a fever evaluation. Cytokine expression was assessed in both adipose tissue and hypothalamus samples. The neural response was assessed in the forebrain immunohistochemistry for c-Fos. Compared with the control group, the fructose diet induced dyslipidemia and significantly higher plasma total cholesterol, HDL-cholesterol, triglyceride, and glucose levels as well as both epididymal and retroperitoneal adiposity. Furthermore, in response to LPS (1 mg/kg), the rats subjected to a fructose diet exhibited exacerbated sickness behaviors and accentuated febrile responses. LPS induced Fos protein expression in several areas of the brains of the control rats; however, higher numbers of Fos-positive cells were observed in the brains of the rats that were fed a fructose diet. Moreover, larger increases in cytokine expression were observed in both the hypothalamus and the adipose tissue of the obese rats compared with the control rats in response to LPS. In this study, fructose diets played an important role in both the induction of metabolic disorders and the modulation of sickness behaviors in response to an immunological challenge, most likely through the induction of cytokines in the hypothalamus.

The effect of oil spills on the bacterial diversity and catabolic function in coastal sediments: a case study on the Prestige oil spill.

The accident of the Prestige oil tanker in 2002 contaminated approximately 900 km of the coastline along the northern Spanish shore, as well as parts of Portugal and France coast, with a mixture of heavy crude oil consisting of polycyclic aromatic hydrocarbons, alkanes, asphaltenes and resins. The capacity of the autochthonous bacterial communities to respond to the oil spill was assessed indirectly by determining the hydrocarbon profiles of weathered oil samples collected along the shore, as well as through isotope ratios of seawater-dissolved CO2, and directly by analyses of denaturing gradient gel electrophoresis fingerprints and 16S rRNA gene libraries. Overall, the results evidenced biodegradation of crude oil components mediated by natural bacterial communities, with a bias towards lighter and less substituted compounds. The changes observed in the Proteobacteria, the most abundant phylum in marine sediments, were related to the metabolic profiles of the sediment. The presence of crude oil in the supratidal and intertidal zones increased the abundance of Alpha- and Gammaproteobacteria, dominated by the groups Sphingomonadaceae, Rhodobacteraceae and Chromatiales, whilst Gamma- and Deltaproteobacteria were more relevant in subtidal zones. The phylum Actinobacteria, and particularly the genus Rhodococcus, was a key player in the microbial response to the spill, especially in the degradation of the alkane fraction. The addition of inorganic fertilizers enhanced total biodegradation rates, suggesting that, in these environments, nutrients were insufficient to support significant growth after the huge increase in carbon sources, as evidenced in other spills. The presence of bacterial communities able to respond to a massive oil input in this area was consistent with the important history of pollution of the region by crude oil.

Characterization of the anaerobic microbial community in oil-polluted subtidal sediments: aromatic biodegradation potential after the Prestige oil spill.

The influence of massive crude oil contamination on the microbial population of coastal sediments was investigated in the Cíes Islands 18 and 53 months after the tanker Prestige sank off the NW coast of Spain. Communities were studied by means of culturable and non-culturable methods at three horizons in the sediment (2-5 cm, 12-15 cm and 25-30 cm) in an area heavily affected by the spill. Most probable number of aerobic hydrocarbon degraders was highest in the upper zone and decreased dramatically with depth. Aromatic oxidizing nitrate-reducing bacteria counts were slightly higher than aerobes in the oxidized layer, and also decreased considerably with depth. Iron-reducing bacteria were barely detectable. The highest counts were obtained for sulfate-reducing bacteria, which represented the most relevant fraction of aromatic oxidizers, being maximal at 12-15 cm depth. The community response to high pollution levels was characterized by an increase in culturable populations active towards crude oil components despite the strong decay in the total cell counts. Analysis of whole 16S rRNA gene libraries obtained from the two sampling times and different depths (1460 sequences in all) showed a predominance of Gamma- and Deltaproteobacteria, which was confirmed by fluorescent in situ hybridization. Desulfobacteraceae was the most abundant group among Deltaproteobacteria, followed by sequences affiliated with the order Myxococcales. All retrieved sequences of this order affiliated with a marine myxobacterial clade. Interestingly, sequences affiliated to the order Desulfarculales constituted half of the Deltaproteobacteria sequences retrieved from the heaviest contaminated sample. Principal coordinates analysis of 16S rRNA gene libraries suggested fluctuation in the community distribution with time. Changes in the abundance of certain groups such as Bacteroidetes contributed to these observed differences. Although predominance of certain metabolic types in each horizon could be delimited, a considerable overlap in the use of electron acceptors was observed, confirming that each selected zone could be influenced by more than one respiratory metabolism. Altogether, our results evidence the presence in these sediments of a microbial community with potential to respond against hydrocarbon contamination, consistent with the long pollution history of the site.

Response of sulfate-reducing bacteria to an artificial oil-spill in a coastal marine sediment.

In situ mesocosm experiments using a calcareous sand flat from a coastal area of the island of Mallorca in the Mediterranean Sea were performed in order to study the response of sulfate-reducing bacteria (SRB) to controlled crude oil contamination, or heavy contamination with naphthalene. Changes in the microbial community caused by the contamination were monitored by a combination of comparative sequence analysis of 16S rRNA genes, fluorescence in situ hybridization, cultivation approaches and metabolic activity rates. Our results showed that crude oil and naphthalene negatively influenced the total microbial community as the natural increase in cell numbers due to the seasonal dynamics was attenuated. However, both contaminants enhanced the sulfate reduction rates, as well as the culturability of SRB. Our results suggested the presence of autochthonous deltaproteobacterial SRBs that were able to degrade crude oil or polycyclic aromatic hydrocarbons such as naphthalene in anaerobic sediment layers.

Effect of oil refinery sludges on the growth and antioxidant system of alfalfa plants.

The refining process in the petrochemical industry generates oil refinery sludges, a potentially contaminating waste product, with a high content of hydrocarbons and heavy metals. Faster degradation of hydrocarbons has been reported in vegetated soils than in non-vegetated soils, but the impact of these contaminants on the plants physiology and on their antioxidant system is not well known. In this study, the effect of the addition of petroleum sludge to soil on the physiological parameters, nutrient contents, and oxidative and antioxidant status in alfalfa was investigated. An inhibition of alfalfa growth and an induction of oxidative stress, as indicated by an increase in protein oxidation, were found. Also, the superoxide dismutase isoenzymes, peroxidase, and those enzymes involved in the ascorbate-glutathione cycle showed significant activity increases, parallel to an enhancement of total homoglutathione, allowing plants being tolerant to this situation. This information is necessary to establish successful and sustainable plant-based remediation strategies.

Evidence for in situ crude oil biodegradation after the Prestige oil spill.

In November 2002, the oil tanker Prestige sank off the Spanish coast after releasing approximately 17,000 tones of heavy fuel, coating several hundred kilometers of coastline in oil sludge. In December 2002 and February 2003, samples were collected from the shore of the Galician coast to analyse the indigenous population ability to carry out crude oil degradation in situ. Carbon isotopic ratio of the dissolved inorganic carbon (DIC) in seawater samples was used as a rapid method to directly assess activity of microbes on the oil components. 12CO2/13CO2 ratio in samples from certain locations along the coast revealed degradation of a very delta13C-negative source such as the Prestige crude oil (-30.6 per thousand). Putative biodegradation processes taking place at areas with high income of fresh seawater could not be detected with this technique. Laboratory-scale biostimulation processes carried out in samples with the highest oil biodegradation activity showed that N/P deficiency in seawater is a limiting factor for crude oil degradation. The most probable number (MPN) of crude oil component degraders was estimated for several aromatic compounds (naphthalene, anthracene, phenanthrene, pyrene) and for undecane. Our results clearly show that bacteria present in the contaminated water are readily able to transform components of the crude oil into inorganic carbon.