Evaluating the long term effectiveness of a Mediterranean marine protected area to tackle the effects of invasive and range expanding herbivorous fish on rocky reefs.

Here we provide evidence, along an 8-year period time-series based on multifaceted data from a Mediterranean marine protected area (MPA), whether protection can tackle invasive and range expanding herbivore fishes, and their effects on the algal resource availability, taking into account the population trends of predatory fishes, fisheries catches of herbivore fishes and sea surface temperature (SST) through time. Our findings pointed out that an ineffective in restoring top-down control process MPA may facilitate, rather than alleviate, the sudden and enduring population burst of invasive and range-expanding herbivorous fishes at tipping points of abrupt change. This subsequently results in the deterioration of rocky reef habitats and the depletion of algal resources, with the tipping points of abrupt change for algal and herbivore fish species not overlapping chronologically. As sea temperature increases, ineffective or recently established MPAs may inadvertently facilitate the proliferation of invasive and range-expanding species, posing a significant challenge to management effectiveness and conservation objectives.

Effects of marine noise pollution on Mediterranean fishes and invertebrates: A review.

Marine noise pollution (MNP) can cause a multitude of impacts on many organisms, but information is often scattered and general outcomes difficult to assess. We have reviewed the literature on MNP impacts on Mediterranean fish and invertebrates. Both chronic and acute MNP produced by various human activities - e.g. maritime traffic, pile driving, air guns - were found to cause detectable effects on intra-specific communication, vital processes, physiology, behavioral patterns, health status and survival. These effects on individuals can extend to inducing population- and ecosystem-wide alterations, especially when MNP impacts functionally important species, such as keystone predators and habitat forming species. Curbing the threats of MNP in the Mediterranean Sea is a challenging task, but a variety of measures could be adopted to mitigate MNP impacts. Successful measures will require more accurate information on impacts and that effective management of MNP really becomes a priority in the policy makers' agenda.

Matching genetics with oceanography: directional gene flow in a Mediterranean fish species.

Genetic connectivity and geographic fragmentation are two opposing mechanisms determining the population structure of species. While the first homogenizes the genetic background across populations the second one allows their differentiation. Therefore, knowledge of processes affecting dispersal of marine organisms is crucial to understand their genetic distribution patterns and for the effective management of their populations. In this study, we use genetic analyses of eleven microsatellites in combination with oceanographic satellite and dispersal simulation data to determine distribution patterns for Serranus cabrilla, a ubiquitous demersal broadcast spawner, in the Mediterranean Sea. Pairwise population F(ST) values ranged between -0.003 and 0.135. Two genetically distinct clusters were identified, with a clear division located between the oceanographic discontinuities at the Ibiza Channel (IC) and the Almeria-Oran Front (AOF), revealing an admixed population in between. The Balearic Front (BF) also appeared to dictate population structure. Directional gene flow on the Spanish coast was observed as S. cabrilla dispersed from west to east over the AOF, from north to south on the IC and from south of the IC towards the Balearic Islands. Correlations between genetic and oceanographic data were highly significant. Seasonal changes in current patterns and the relationship between ocean circulation patterns and spawning season may also play an important role in population structure around oceanographic fronts.

Specific inhibition of kynurenate synthesis enhances extracellular dopamine levels in the rodent striatum.

Fluctuations in the endogenous levels of kynurenic acid (KYNA), a potent alpha7 nicotinic and NMDA receptor antagonist, affect extracellular dopamine (DA) concentrations in the rat brain. Moreover, reductions in KYNA levels increase the vulnerability of striatal neurons to NMDA receptor-mediated excitotoxic insults. We now assessed the role of a key KYNA-synthesizing enzyme, kynurenine aminotransferase II (KAT II), in these processes in the rodent striatum, using KAT II KO mice-which have reduced KYNA levels-and the selective KAT II inhibitor (S)-4-(ethylsulfonyl)benzoylalanine (S-ESBA) as tools. S-ESBA (applied by reverse dialysis) raised extracellular DA levels in the striatum of KYNA-deficient mice threefold and caused a much larger, 15-fold increase in wild-type mice. In the rat striatum, S-ESBA produced a 35% reduction in extracellular KYNA, which was accompanied by a 270% increase in extracellular DA. The latter effect was abolished by co-infusion of 100 nM KYNA. Intrastriatal S-ESBA pre-treatment augmented the size of a striatal quinolinate lesion by 370%, and this potentiation was prevented by co-infusion of KYNA. In separate animals, acute inhibition of KAT II reduced the de novo synthesis of KYNA during an early excitotoxic insult without enhancing the formation of the related neurotoxic metabolites 3-hydroxykynurenine and quinolinate. Taken together, these results provide further support for the concept that KAT II is a critical determinant of functionally relevant KYNA fluctuations in the rodent striatum.

Dopamine receptor activation reveals a novel, kynurenate-sensitive component of striatal N-methyl-D-aspartate neurotoxicity.

The N-methyl-d-aspartate (NMDA) subtype of glutamate receptors plays an important role in brain physiology, but excessive receptor stimulation results in seizures and excitotoxic nerve cell death. NMDA receptor-mediated neuronal excitation and injury can be prevented by high, non-physiological concentrations of the neuroinhibitory tryptophan metabolite kynurenic acid (KYNA). Here we report that endogenous KYNA, which is formed in and released from astrocytes, controls NMDA receptors in vivo. This was revealed with the aid of the dopaminergic drugs d-amphetamine and apomorphine, which cause rapid, transient decreases in striatal KYNA levels in rats. Intrastriatal injections of the excitotoxins NMDA or quinolinate (but not the non-NMDA receptor agonist kainate) at the time of maximal KYNA reduction resulted in two- to threefold increases in excitotoxic lesion size. Pre-treatment with a kynurenine 3-hydroxylase inhibitor or with dopamine receptor antagonists, i.e., two classes of pharmacological agents that prevented the reduction in brain KYNA caused by dopaminergic stimulation, abolished the potentiation of neurotoxicity. Thus, the present study identifies a previously unappreciated role of KYNA as a functional link between dopamine receptor stimulation and NMDA neurotoxicity in the striatum.

Relationships among predatory fish, sea urchins and barrens in Mediterranean rocky reefs across a latitudinal gradient.

Previous studies conducted on a local scale emphasised the potential of trophic cascades in Mediterranean rocky reefs (involving predatory fish, sea urchins and macroalgae) in affecting the transition between benthic communities dominated by erected macroalgae and barrens (i.e., bare rock with partial cover of encrusting algae). Distribution patterns of fish predators of sea urchins (Diplodus sargus sargus, Diplodus vulgaris, Coris julis and Thalassoma pavo), sea urchins (Paracentrotus lividus and Arbacia lixula) and barrens, and fish predation rates upon sea urchins, were assessed in shallow (3-6m depth) sublittoral rocky reefs in the northern, central and southern sectors of the eastern Adriatic Sea, i.e., on a large spatial scale of hundreds of kilometres. No dramatic differences were observed in predatory fish density across latitude, except for a lower density of small D. sargus sargus in the northern Adriatic and an increasing density of T. pavo from north to south. P. lividus did not show any significant difference across latitude, whereas A. lixula was more abundant in the southern than in the central Adriatic. Barrens were more extended in the southern than in the central and northern sectors, and were related with sea urchin density. Fish predation upon adult sea urchins did not change on a large scale, whereas it was slightly higher in the southern sector for juveniles when predation rates of both urchins were pooled. Results show that: (1) assemblages of predatory fish and sea urchins, and barren extent change across latitude in the eastern Adriatic Sea, (2) the weak relations between predatory fish density and predation rates on urchins reveal that factors other than top-down control can be important over large scale (with the caveat that the study was conducted in fished areas) and (3) patterns of interaction among strongly interacting taxa could change on large spatial scales and the number of species involved.

Chronic neuroleptic treatment reduces endogenous kynurenic acid levels in rat brain.

The brain and cerebrospinal fluid levels of kynurenic acid (KYNA), a metabolite of the kynurenine pathway of tryptophan degradation and antagonist of the glycine(B) receptor and the alpha7 nicotinic acetylcholine receptor, are elevated in persons with schizophrenia. To evaluate whether this increase is related to antipsychotic medication, we examined the effects of haloperidol (HAL), clozapine (CLOZ) or raclopride (RAC) on brain KYNA levels in rats. Animals received either acute drug injections or ingested the drugs chronically with the drinking water. Acute application or one-week drug exposure had no effect on brain KYNA levels. After one month, HAL, CLOZ and RAC all caused significant reductions in KYNA levels in striatum, hippocampus and frontal cortex. Quantitatively similar reductions in the brain tissue content of KYNA were observed after one year of HAL administration. All these effects were accompanied by equivalent decreases in the extracellular concentration of KYNA, measured by striatal microdialysis. Separate animals received an intrastriatal infusion of (3)H-kynurenine to probe the entire kynurenine pathway acutely in rats treated with HAL for one year. These animals showed reduced (3)H-KYNA production, but no changes in the formation of other kynurenine pathway metabolites. By enhancing glutamatergic and cholinergic neurotransmission, reduced brain KYNA levels may play a role in the clinical effects of prolonged antipsychotic medication.

Evaluating the effects of protection on fish predators and sea urchins in shallow artificial rocky habitats: a case study in the northern Adriatic Sea.

Man-made defence structures (e.g., breakwaters, jetties) are becoming common features of marine coastal landscapes all around the world. The ecology of assemblages of species associated with such artificial structures is, however, poorly known. In this study, we evaluated the density and size of fish predators of echinoids (i.e., Diplodus sargus, Diplodus vulgaris, Sparus aurata), and the density of sea urchins (i.e., Paracentrotus lividus) at defence structures (i.e., breakwaters) inside and outside the marine protected area of Miramare (northern Adriatic Sea) in order to: (1) assess possible differences in fish predator density and size between protected and fished breakwaters; (2) assess whether fish predation may have the potential to affect sea urchin density in artificial rocky habitats. Surveys were carried out at four random times over a period of two years. Total density, and density of medium- and large-sized individuals of the three predatory fishes were generally greater at the protected than at the fished breakwaters, whereas no differences were detected in the density of small-sized individuals. Density of the sea urchin P. lividus did not show any difference between protected and fished breakwaters. The results of this study suggest that: (1) protection may significantly affect predatory fishes in artificial rocky habitats; (2) differences in predatory fish density, and size may be unrelated with the density of the sea urchin P. lividus; (3) protected artificial structures such as breakwaters, originally planned for other purposes, could represent a potential tool for fish population recovery and enhancement of local fisheries.

Desertification of Mediterranean rocky reefs caused by date-mussel, Lithophaga lithophaga (Mollusca: Bivalvia), fishery: effects on adult and juvenile abundance of a temperate fish.

Macroalgal beds in temperate rocky habitats provide shelter and food for many adult reef fishes and their juvenile stages. In the Mediterranean Sea, the fishery of the endolithic date-mussel Lithophaga lithophaga (which involves dismantling of rocky substrates inhabited by these bivalves) may cause formation of barrens in shallow rocky reefs. Preliminary data collected in SW Apulia (SE Italy) show that rocky reefs impacted by this destructive fishery display different distribution patterns of adult Coris julis (a common labrid fish in the Mediterranean basin), and lower abundance of juveniles. The ecological implications of date-mussel fishery for dynamics of fish populations and rocky-reef ecosystem functioning (e.g., nursery role) are discussed.

A diagnosis of left ventricular hypertrophy on ECG is associated with a high cardiovascular risk: findings from a 40- to 69-year-old cohort in general practice.

OBJECTIVE: Left ventricular hypertrophy (LVH) is an independent cardiovascular (CV) risk factor in both sexes. We studied if a diagnosis of LVH on electrocardiogram (ECG) was associated with a 'high CV risk condition' among 40- to 69-year-old individuals cared for by GPs. METHODS: We studied 4250 individuals, 5.4% of whom had LVH. Cross-sectional frequencies, and age- and gender-adjusted statistical differences have been calculated. RESULTS: All the study variables were significantly worse for 'LVH' than 'non-LVH' individuals (except smoking). The 'LVH' had both a mean '5-year CV risk' significantly greater than 'non-LVH' individuals (27.0% versus 8.6%), and a significantly higher prevalence of a '5-year CV risk >15%' (89% versus 15%). CONCLUSIONS: A diagnosis of LVH on ECG among the adult individuals of an opportunistic cohort from general practice was associated with a 6-fold greater prevalence of a 'high CV risk condition'.

GPs' satisfaction with the doctor-patient encounter: findings from a community-based survey.

OBJECTIVE: The aim of this study was to explore the characteristics of the doctor-patient relationship from the GP's point of view. METHODS: We performed a cross-sectional 1-day study in family practice. Thirty-three GPs volunteered to fill in a questionnaire at the end of each of 20 consecutive consultations on an index day. Six hundred and sixty-one patients (out of 665) participated in the study. Descriptive frequencies of GPs' judgements about personal experiences during the consultations, and predictors of GP's global satisfaction score on patient encounters were analysed. RESULTS: The mean age of the 33 GPs was 44.7 +/- 3.6 years. Professional skills (62% of the GPs had no doubts on diagnosis, therapy or prognosis) and the quality of the human/interpersonal interaction were major determinants of GPs' satisfaction in the patient-doctor relationship. Doctors felt professionally esteemed by 90% of their patients, and the median value of their global satisfaction score (matching the expectations from an 'ideal patient' to that experienced when meeting the real one) was very high (median 8, range 1-10). Nevertheless, GPs did not know if they were satisfied with the actual encounter with the patient in about one-third of the consultations. CONCLUSIONS: Professional skills and quality of the human/interpersonal interactions are major determinants of GPs' satisfaction in their professional activities.

Kynurenate production by cultured human astrocytes.

In the rodent brain, astrocytes are known to be the primary source of kynurenate (KYNA), an endogenous antagonist of both the glycine(B) and the alpha7 nicotinic acetylcholine receptor. In the present study, primary human astrocytes were used to examine the characteristics and regulation of de novo KYNA synthesis in vitro. To this end, cells were exposed to KYNA's bioprecursor L-kynurenine, and newly formed KYNA was recovered from the extracellular milieu. The production of KYNA was stereospecific and rose with increasing L-kynurenine concentrations, reaching a plateau in the high microM range. In an analogous experiment, astrocytes also readily produced and liberated the potent, specific glycine(B) receptor antagonist 7-chlorokynurenate from L-4-chlorokynurenine. KYNA synthesis was dose-dependently reduced by L-leucine or L-phenylalanine, two amino acids that compete with L-kynurenine for cellular uptake, and by aminooxyacetate, a non-specific aminotransferase inhibitor. In contrast, KYNA formation was stimulated by 5 mM pyruvate or oxaloacetate, which act as co-substrates of the transamination reaction. Aglycemic or depolarizing (50 mM KCl or 100 microM veratridine) conditions had no effect on KYNA synthesis. Subsequent studies using tissue homogenate showed that both known cerebral kynurenine aminotransferases (KAT I and KAT II) are present in astrocytes, but that KAT II appears to be singularly responsible for KYNA formation under physiological conditions. Taken together with previous results, these data suggest that very similar mechanisms control KYNA synthesis in the rodent and in the human brain. These regulatory events are likely to influence the neuromodulatory effects of astrocyte-derived KYNA in the normal and diseased human brain.

Biological targets of neurotoxic pesticides analysed by alteration of developmental events in the Mediterranean sea urchin, Paracentrotus lividus.

Biological effects of neurotoxic insecticides widely used for agricultural purposes were studied using the early development of the Mediterranean sea urchin Paracentrotus lividus as a model. These compounds, dispersed as aerosols or powders in agricultural regions near to the coast, may affect the health of organisms in the marine environment. The biological effects of Basudin (an organophosphate compound containing 20% Diazinon), Diazinon (Dzn, a thionophosphate), Carbaryl and Pirimicarb (carbamates) on the early phases of sea urchin development were thus investigated. Morphological, biochemical, histochemical and immuno histochemical analyses were performed both during embryo and larval development. For the morphological effects on fertilisation and first cleavages, the effective concentration of insecticides was found to be 10(-4) M, while for further stages concentrations between 10(-5) and 10(-7) M were effective: 10(-3) M of any of these insecticides totally arrested development. During embryonic development, the treatment with organophosphates slowed the rate of early mitotic cycles down, affected nuclear and cytoskeletal status as well as DNA synthesis. From the gastrulation stage onwards, the main effects were exerted on the rate of primary mesenchyme cells migration, larval size, perioral arm length, and acetylcholinesterase activity distribution, thus deregulating the cholinergic system, which modulates cell-to-cell communication mediated by the signal molecule acetylcholine.

The effects of sewage discharge on shallow hard substrate sessile assemblages.

On rocky shores, sewage discharges can modify natural distribution patterns of sessile organisms. The impact of sewage on shallow hard substrate assemblages has been assessed along SW Apulian coast (Ionian Sea, Italy), providing a framework to evaluate the benefits of future sewage displacement to deeper waters. Four locations (three controls and one putatively impacted) were selected and three sites were chosen at each location. Each site was sampled by 10 replicate photographic records. Univariate analyses revealed that the outfall did not affect the spatial distribution of number of taxa, total cover and abundance of some dominant taxa (mostly algae, sponges and bryozoans). The outfall negatively influenced the natural distribution pattern of filamentous green algae, whilst some algae (i.e. Gelidiales and Colpomenia sinuosa) were exclusively present at the impacted location. Multivariate analyses revealed that the outfall heavily modified the natural pattern of variability in the structure of the assemblage.

Evaluating the genotoxic damage and hepatic tissue alterations in demersal fish species: a case study in the Ligurian Sea (NW-Mediterranean).

A protocol for detecting hepatic micronuclei in fish was performed to check genotoxic damage, as an indicator of environmental hydrocarbons exposure, in relation to the "Haven" oil spill. As target fish, we have chosen three demersal species with different habitats and feeding behaviour (i.e., Lepidorhombus boscii, Merluccius merluccius and Mullus barbatus) collected from two differently impacted areas and a control site. Additional analysis was performed by histological detection of hepatic tissue damages such as the presence of necrotic and tumour-like aspects. The three studied species showed different sensitivity to environmental pollutants exposure, L. boscii resulting the more sensitive in terms of both micronuclei incidence and tissue damage. The results of this study show that: (1) the micronucleus test could be an effective and fast method to detect oil pollution; (2) a clear response of L. boscii only to oil contamination for both micronucleus test and liver tissue alterations.

Coastal fish indicate human-induced changes in the Mediterranean littoral.

Coastal fish assemblages were studied to assess two sorts of human impacts in southwestern Apulia (SE Italy, Mediterranean Sea). Fish assemblages were evaluated by visual census along two rocky locations impacted by a sewage outfall discharging nearshore (S) and by date-mussel (Lithophaga lithophaga) fisheries (F), respectively, and at two control locations (Cs). Multivariate analyses showed that fish assemblage structures at S and F differed from those at Cs. Asymmetric ANOVAs indicated that species richness were significantly lower both at S (approximately 27%) and at F (approximately 35%) compared with Cs. Total fish abundance was 5- to 7-fold higher at S than at Cs, while the values recorded at F were comparable to those of Cs. At S, average abundances of planktivorous fish and POM feeders were higher, and those of labrids and sparids of the genus Diplodus were lower, respectively, than at Cs. Labrids of the genus Symphodus and small serranids were significantly less abundant at F than Cs. Data suggested that coastal fish respond to the impact caused by the sewage discharge and provided a framework to assess potential benefits of its future displacement to deeper waters. For the first time, moreover, this study provided suggestive evidence that the habitat destruction caused by the illegal date-mussel fisheries may affect fish assemblages.

Cytochrome oxidase activity is increased in +/Lc Purkinje cells destined to die.

+/Lc Purkinje cells degenerate postnatally because of a gain-of-function mutation in the delta2 glutamate receptor (Grid2) that causes a constitutive Na+ current leak. The effect of the resulting chronic depolarization on Purkinje cell metabolism was investigated by measuring levels of cytochrome oxidase (COX) activity in Purkinje cell dendrites using quantitative densitometry. Analysis of wild type controls and +/Lc mutants at P10, P15 and P25 showed that levels of COX activity were significantly increased above control levels by P15 and continued to increase through P25. The increase in COX activity is likely to reflect an increase in oxidative phosphorylation to accommodate the energy demands of removing excess Na+ and Ca2+ entering the Purkinje cells in response to the Grid2 leak current.

Early degenerative changes in transgenic mice expressing mutant huntingtin involve dendritic abnormalities but no impairment of mitochondrial energy production.

Mitochondrial defects, which occur in the brain of late-stage Huntington's disease (HD) patients, have been proposed to underlie the selective neuronal loss in the disease. To shed light on the possible role of mitochondrial energy impairment in the early phases of HD pathophysiology, we carried out Golgi impregnation and quantitative histochemical/biochemical studies in HD full-length cDNA transgenic mice that were symptomatic but had not developed to a stage in which neuronal loss could be documented. Golgi staining showed morphologic abnormalities that included a significant decrease in the number of dendritic spines and a thickening of proximal dendrites in striatal and cortical neurons. In contrast, measurements of mitochondrial electron transport Complexes I-IV did not reveal changes in the striatum and cerebral cortex in these mice. Examination of the neostriatum and cerebral cortex in human presymptomatic and pathological Grade 1 HD cases also showed no change in the activity of mitochondrial Complexes I-IV. These data suggest that dendritic alterations precede irreversible cell loss in HD, and that mitochondrial energy impairment is a consequence, rather than a cause, of early neuropathological changes.

Detecting environmental impacts on the Mediterranean seagrass Posidonia oceanica (L.) Delile: the use of reconstructive methods in combination with 'beyond BACI' designs.

Interannual changes in leaf production and rhizome elongation rates of the seagrass Posidonia oceanica have been evaluated by means of reconstructive methods at the Travello meadow (Ligurian Sea, NW Mediterranean, Italy) to provide evidence of responses to the putative impact of a beach replenishment made with terrigenous materials in 1993. Two additional meadows (Genoa-Quinto and Noli) were sampled as controls. An asymmetrical sampling design ('beyond BACI': Before/After, Control/Impact) was thus used to detect the impact on the basis of a single sampling as dating methods obviated the lack of pre-impact data. At all three meadows investigated, leaf production and rhizome elongation rates were reconstructed for 12 previous years (from 1988 to 1999). A marked decrease in the leaf production rate (around 20%) was assessed only at Travello immediately after the putative disturbance. Control meadows, instead, did not display any significant variations in the pattern of change of this variable from before to after the putative impact. With regard to rhizome growth rates, no significant changes in space and time attributable to the putative impact have been detected. The present data also suggest that the impact studied may be considered as a pulse disturbance, since leaf production appeared to recover over a comparatively short-time scale (around 2-3 years) if compared to the low turn-over and high longevity of P. oceanica. The high potential of asymmetrical sampling designs in combination with dating methods is discussed in the light of the results presented here.

Kynurenergic manipulations influence excitatory synaptic function and excitotoxic vulnerability in the rat hippocampus in vivo.

Competing enzymatic mechanisms degrade the tryptophan metabolite L-kynurenine to kynurenate, an inhibitory and neuroprotective compound, and to the neurotoxins 3-hydroxykynurenine and quinolinate. Kynurenine 3-hydroxylase inhibitors such as PNU 156561 shift metabolism towards enhanced kynurenate production, and this effect may underlie the recently discovered anticonvulsant and neuroprotective efficacy of these drugs. Using electrophysiological and neurotoxicological endpoints, we now used PNU 156561 as a tool to examine the functional interplay of kynurenate, 3-hydroxykynurenine and quinolinate in the rat hippocampus in vivo. First, population spike amplitude in area CA1 and the extent of quinolinate-induced excitotoxic neurodegeneration were studied in animals receiving acute or prolonged intravenous infusions of L-kynurenine, PNU 156561, (L-kynurenine+PNU 156561) or kynurenate. Only the latter two treatments, but not L-kynurenine or PNU 156561 alone, caused substantial inhibition of evoked responses in area CA1, and only prolonged (3h) infusion of (L-kynurenine+PNU 156561) or kynurenate was neuroprotective. Biochemical analyses in separate animals revealed that the levels of kynurenate attained in both blood and brain (hippocampus) were essentially identical in rats receiving extended infusions of L-kynurenine alone or (L-kynurenine+PNU 156561) (4 and 7microM, respectively, after an infusion of 90 or 180min). However, addition of the kynurenine 3-hydroxylase inhibitor resulted in a significant decrement in the formation of 3-hydroxykynurenine and quinolinate in both blood and brain. These data suggest that the ratio between kynurenate and 3-hydroxykynurenine and/or quinolinate in the brain is a critical determinant of neuronal excitability and viability. The anticonvulsant and neuroprotective potency of kynurenine 3-hydroxylase inhibitors may therefore be due to the drugs' dual action on both branches of the kynurenine pathway of tryptophan degradation.