Coastal geomorphology and oceanographic features shape subtidal benthic communities in management areas of central Chile

1. The spatial variation in community structure among 30 areas for the management and exploitation of benthic resources (AMEBRs) in central Chile was assessed from surveys conducted during the same spring–summer season. One hundred taxa identified in the subtidal surveys were grouped into 10 functional groups.
2. The influence and relative importance of external factors over benthic associations were assessed through nonmetric multidimensional scaling (NMDS) and path analysis. Three main categories of external factors were considered: ‘terrain traits’ (e.g. coastline exposure), ‘surface-ocean conditions’ (e.g. sea surface temperature, SST), and ‘fishery-related variables’ (e.g. cumulative landings).
3. The NMDS revealed a strong association between benthic community structure and both terrain and surface-ocean conditions (42% of variance explained by permutational multivariate analysis of variance), but not with fishery-related variables. Assemblages typical of rocky substrates were associated with larger seasonal fluctuations in SST and surface chlorophyll a. The presence of soft-bottom functional groups was associated with higher levels of surface fluorescence and larger seasonal fluctuations in a satellite-derived proxy for river-plume influence (nLw645).
4. A path analysis model for hard-bottom communities reached a 49% goodness of fit (GOF), with the presence of epifaunal filter-feeders, grazers, predators, and scavengers being significantly correlated with leathery and corticated foliose algae, which in turn depend on the fraction of rocky substrate in the AMEBR; the fraction of rocky substrate is positively correlated with coastline exposure.
5. The model for soft-bottom communities reached a 52% GOF with the presence of infaunal filter-feeders and epifaunal detritivores depending directly on SST and surface chlorophyll a. The fishery-related variables considered in the model had no apparent effect on the structure of either type of subtidal community.
6. These results provide a hierarchy of physical–biological associations determining the functional composition of subtidal benthic communities in management areas along central Chile. This knowledge may improve future assessments of ecosystem response to changes in environmental conditions and management strategies.

     

Cobia Rachycentron canadum L. reared in low‐salinity water: does dietary sodium chloride affect growth and osmoregulation?

The effects of NaCl supplementation (0.0%, 2.5%, 5.0%, 7.5% and 10.0% dry weight of a basal diet) on growth, gill histological alterations and osmoregulation of juvenile cobia reared in low‐salinity water (5 g L^?1) were assessed. At the end of the experiment, gills were sampled for Na⁺, K⁺‐ATPase activity determination and histological evaluation. In all treatments, no mortality was observed. Results showed that dietary NaCl supplementation did not alter growth. At the highest supplementations (7.5% and 10.0%), juvenile cobia showed higher feed intake and feed conversion ratio. Na⁺, K⁺‐ATPase activity was higher in fish fed the diet without salt supplementation than in those fed with NaCl‐supplemented diets. The number of chloride cells significantly increased with increasing dietary salt level, being 2.5‐fold higher in fish fed with 10.0% NaCl supplementation (41 cells mm^?2) than in those from the non‐supplemented fed group (16 cells mm^?2). These findings indicate that dietary salt supplementation stimulated chloride cell proliferation paralleled with a reduction in the gill Na⁺, K⁺‐ATPase activity, suggesting a possible decrease in energy consumption associated with osmoregulation. However, the suggested energy sparing did not have a significant impact on juvenile cobia growth.     

Molecular and physiological characterisation of psychrotrophic hydrocarbon-degrading bacteria isolated from Terra Nova Bay (Antarctica)

A set of 21 Antarctic marine bacteria isolated from the Ross Sea and able to utilise diesel fuel as the sole carbon and energy source was characterised. Isolates were analysed by amplified 16S rDNA restriction analysis using the enzyme AluI, resulting in two different groups corresponding to different bacterial species. These species were assigned to the genera Rhodococcus and Alcaligenes, on the basis of 16S rDNA sequencing. This low degree of inter-specific biodiversity was parallel to a low intra-specific biodiversity, as shown by Random Amplified Polymorphic DNA analysis. Then, a 550-bp DNA fragment coding for the inner region of alkane mono-oxygenase was PCR-amplified from the genome of each strain. The phylogenetic analysis of the sequence of the putative AlkB protein coded for by the amplified DNA fragment revealed that these alkB genes were very likely inherited by horizontal gene transfer. Lastly, the analysis of the biodegradation ability of four strains revealed two different strategies of hydrocarbon uptake, mediated either by bio-surfactants and peculiar of Rhodococcus isolates, or by membrane modifications and shown by Alcaligenes isolates. In order to understand the interrelationships between hydrocarbon-degrading isolates, the dynamics of two strains, belonging to Rhodococcus and Alcaligenes, grown together in a co-culture was also followed over a seventeen days period.     

Synergistic Interaction Between Tomato chlorosis virus and Tomato spotted wilt virus Results in Breakdown of Resistance in Tomato

ABSTRACT Multiple viral infections frequently are found in single plants of cultivated and wild hosts in nature, with unpredictable pathological consequences. Synergistic reactions were observed in mixed infections in tomato plants doubly infected with the positive-sense and phloem-limited single-stranded RNA (ssRNA) crinivirus Tomato chlorosis virus (ToCV) and the negative-sense ssRNA tospovirus Tomato spotted wilt virus (TSWV). Synergism in a tomato cultivar susceptible to both viruses resulted in a rapid death of plants. A pronounced enhancement of ToCV accumulation mediated by TSWV co-infection was observed with no evident egress of ToCV from phloem tissues. No consistent alteration of TSWV accumulation was detected. More remarkable was the synergism observed in tomato cultivars which carry the Sw-5 resistance gene, which are resistant to TSWV. Pre-infection with ToCV resulted in susceptibility to TSWV, whereas co-inoculations did not. This suggested that a threshold level or a time lapse is needed for ToCV to interfere or downregulate the defense response in the TSWV-resistant plants.     

Egg quality criteria in Pacific red snapper (Lutjanus peru)

The aim of this study was to evaluate the biochemical parameters used as possible determinants of egg quality in Pacific red snapper (Lutjanus peru). Fertilized eggs of eight spawns were obtained by hormonal induction. Egg quality criteria, including abnormal cleavage (AC), hatching percentage (HR) and survival percentage at first feeding (SR) were recorded. Samples were taken during embryonic development and from yolk‐sac larvae. Proteins, energetic metabolite concentrations and metabolic and digestive enzyme activities were determined using colorimetric methods. Pearson's correlation, and simple and multiple regression models were performed using the biochemical parameters as the independent variables and AC, HR and SR as the dependant variables. Glucose‐6‐phosphatase activity (AC r = 0.87; HR r = ?0.65; SR r = ?0.67) and fructose concentration (AC r = ?0.64; HR r = 0.54; SR r = 0.64) were the only biochemical parameters to be strongly correlated with the three egg quality criteria. The use of multiple regression models increased the regression coefficient of the three quality criteria. Fructose, glucose and glucose‐6‐phosphatase were involved in all multiple regression models. The models proposed in this study may be used to explain egg quality for Pacific red snapper and their use as predictors of egg quality is discussed.     

Determination of reference intervals for metabolic profile of Hanwoo cows at early,middle and late gestation periods

Background: Metabolic profile was initially designed as a presymptomatic diagnostic aid based on statistical analyses of blood metabolites to provide an early warning of certain types of metabolic disorder. However, there is little metabolic profile data available about Korean Hanwoo cows. Therefore, this study aimed to determine the reference intervals of metabolic profile for Korean Hanwoo cows.Methods: Healthy animals(2,205) were selected and divided into early(day 1 to 95), middle(day 96 to 190) and late(day 191 to 285) period according to their gestating period. Metabolic profile including total protein(TP), albumin(Alb), urea(UREA), glucose(Glu), total cholesterol(T-Cho), long-chain fatty acid(LCFA), aspartate aminotransferase(AST),gamma-glutamyl transpeptidase(GGT), creatinine(Crea), calcium(Ca), inorganic phosphorous(i P) and magnesium(Mg)were analyzed using a TBA-40 FR automatic biochemical analyzer. The data of Korean Hanwoo cows were then compared to those of the Japanese Wagyu cows.Results: Most of the data of the Korean Hanwoo cows were relatively higher than those of Japanese Wagyu cows, with the exception of Glu and GGT. This may indicate that the nutritional level of feed for the Korean Hanwoo cows was higher than that of the Japanese Wagyu cows because of the different feeding system. In particular, relatively higher levels of UREA and LCFA were observed in the Korean Hanwoo cows, and this may also contribute to the low reproduction efficiency.Conclusions: These findings may provide some theoretical basis for understanding the reproductive and feeding situation of Korean Hanwoo cows.     

Assessment of efficiency and impacts of gillnets on fish conservation in a tropical freshwater fishery

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Relationships between biological and physico-chemical soil characteristics in a mediterranean agricultural area

Fourteen agricultural soils from various areas of Tuscany were characterized by a range of measurements indicative of soil biological activity. The objective of our research was to identify soil parameters suitable as indicators for evaluating their quality. In general, enzyme activities were found to vary widely, with the highest activity for each enzyme being distributed among only five of the 14 soils studied. The narrowest range (14-fold) in enzyme activities for the various soils was observed for catalase and the widest range (577-fold) for g -glucosidase. Biomass C and, among the measured enzyme activities, amylase, were well correlated with total organic carbon, total N, cation and anion exchange capacity. Positive correlations were found between the maximum water holding capacity and dehydrogenase, amylase, biomass C, FDA hydrolytic activity, the biological index of fertility and the enzyme activity number, so showing that soil moisture may play an important role in affecting soil biological characteristics. No significant correlations were observed among the soil enzymes themselves. The FDA hydrolytic activity appeared to be the index most related with the other biological characteristics tested in this study and, for this reason, can be considered the most effective index for putting in evidence relationships existing between the different biological characteristics in the soils investigated.     

Efficacy of albendazole and moxidectin and resistance to ivermectin against Libyostrongylus douglassii and Libyostrongylus dentatus in ostriches

Anthelmintic resistance has emerged globally as a problem amongst nematode of livestock and has been particularly well documented in equine and small ruminants. There are no studies regarding the efficacy of anthelmintics against the hematophagous nematodes in ostriches, Libyostrongylus dentatus; and just a few on L. douglassii. Here the efficacy of albendazole, ivermectin and moxidectin were evaluated against these two species in an ostrich farm in Minas Gerais state, Brazil. The feces were collected on the day of treatment and after 13days of an oral dose of albendazole (6mg/kg), or an injected dose (0.2mg/kg) of ivermectin or moxidectin. The fecal egg count reduction test and coprocultures were performed to determine possible resistance against the drugs used. An efficacy of 60% was found for ivermectin, while albendazole and moxidectin were 100% effective. Both worm species appeared to have reduced sensitivity to ivermectin.     

Antioxidant and antimutagenic properties of Hibiscus tiliaceus L. methanolic extract

The genus Hibiscus thrives in a variety of climates and produces a diversity of natural compounds with bioactive properties. We have studied the chemical composition and the in vivo antioxidant properties of Hibiscus tiliaceus L. methanolic flower extract, as well as its mutagenic/antimutagenic effects. Vitamin E and some stigmasterol derivatives that might confer an antioxidant effect to the extract were present. Treatment with this extract protected several Saccharomyces cerevisiae strains defective in antioxidant defenses against H2O2 and t-BOOH cytotoxicities, showing a clear antioxidant activity. The effect is the same for all strains used, independent of the antioxidant defense disrupted, suggesting that protection may be due to molecules that act as versatile and wide spectrum nonenzymatic antioxidants, such as vitamins or phytosterols. The extract was not mutagenic in either Salmonella typhimurium or S. cerevisiae and showed a significant antimutagenic action against oxidative mutagens in S. cerevisiae.