Microbial Growth Models in Gilthead Sea Bream (Sparus aurata) Stored in Ice

ABSTRACT

This study analyzes microbiological changes in whole, ungutted farmed gilthead sea bream (Sparus aurata) stored for an 18-day period in ice using traditional methods for mesophilic aerobic bacteria, psychrotrophic, Pseudomonas spp., Aeromonas spp., Shewanella putrefaciens, Enterobacteriaceae, sulphide-reducing Clostridium (Clostridia), and Photobacterium phosphoreum in muscle, skin, and gills, evaluating their seasonal differentiation. Two different statistical models were used to analyze microbiological growth. Simultaneously, physicochemical parameters such as the temperature, pH, biological oxygen demand (BOD), total dissolved solids, salinity, ammonia nitrogen, and total phosphorus content of growing waters were analyzed. The results showed that by the end of the storage time, specific spoilage bacteria (SSB) such as Pseudomonas spp., Aeromonas spp., and S. putrefaciens as H₂S-producing bacteria were dominant in sea bream harvested in temperate water in the Canary Islands. Muscle tissue had the least contamination, followed by skin and gills. The values of the analyzed seawater parameters were constant during the four seasons, except that the temperature showed a small difference between winter and summer. Seasonal effects were observed among the fish analyzed, suggesting that the lower levels of contamination detected in winter may have been due to the slight difference observed in water temperature in that season.     

Assessment of vineyard water status variability by thermal and multispectral imagery using an unmanned aerial vehicle (UAV)

The goal of this study was to assess the water status variability of a commercial rain-fed Tempranillo vineyard (Vitis vinifera L.) by thermal and multispectral imagery using an unmanned aerial vehicle (UAV). The relationships between aerial temperatures or indices derived from the imagery and leaf stomatal conductance (g _s) and stem water potential (Ψ_stem) were determined. Aerial temperature was significantly correlated with g _s (R ²?=?0.68, p?<?0.01) and Ψ_stem (R ²?=?0.50, p?<?0.05). Furthermore, the thermal indices derived from aerial imagery were also strongly correlated with Ψ_stem and g _s. Moreover, different spectral indices were related to vineyard water status, although NDVI (normalized difference vegetation index) and TCARI/OSAVI (ratio between transformed chlorophyll absorption in reflectance and optimized soil-adjusted vegetation index) showed the highest coefficient of determination with Ψ_stem (R ²?=?0.68, p?<?0.05) and g _s (R ²?=?0.84, p?<?0.05), respectively. While the relationship with thermal imagery and water status parameters could be considered as a short-term response, NDVI and TCARI/OSAVI indices were probably reflecting the result of cumulative water deficits, hence a long-term response. In conclusion, thermal and multispectral imagery using an UAV allowed assessing and mapping spatial variability of water status within the vineyard.     

Influence of Habitat and Land Use on the Assemblages of Ephemeroptera,Plecoptera, and Trichoptera in Neotropical Streams

Insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are often used to assess the conditions of aquatic environments, but few studies have examined the differences in these communities between riffles and pools. Our objective was to test whether riffles shelter greater richness and abundance of EPT, as well as to assess the sensitivity of these insects for detecting impacts from different land uses in streams in southeastern Brazil. Samples were collected in the dry season of 2012 with a Surber sampler in riffles and pools of nine streams (forest, pasture, and urban areas). Principal component analysis distinguished the streams according to different land uses as a function of percentage of plant cover and water oxygenation level and showed partial distinction between riffles and pools as a function of current speed and percentage of ultrafine sand. Detrended correspondence analysis indicated the distinction in EPT composition between riffles and pools, except in urban streams. The results of this study confirm the expected differences in the EPT fauna structure between riffles and pools, especially in forest and pasture environments. The individual metrics of riffle and pool assemblages showed significantly different responses to land use. Therefore, we suggest individual sampling of riffles and pools, since the metrics of these assemblages’ insects can differ between these habitats and influence the results of assessments in low-order streams.     

Biochemical responses associated with common bean defence against Sclerotinia sclerotiorum

The aim of this study was to investigate changes in defence compounds of common bean cultivars with different levels of resistance to the fungus Sclerotinia sclerotiorum and determine the relation of the compounds to pathogen tolerance. The lines were inoculated with the pathogen and assessed for enzymatic and non-enzymatic parameters related to plant defence: peroxidases (POX), polyphenol oxidases (PPO), catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX), total soluble phenol and lignin contents. Stem tissue samples were collected from two regions of the plant for biochemical analyses. Stem tissue samples were collected from two regions of the plant for biochemical analyses. In the position one, 5 cm of the stem was collected from the region with necrosis caused by the pathogen, and in the position two, 5 cm of the stem was collected from the end of the position one at the times of 12, 24, 48, 72, 96 and 120 h after inoculation (HAI). Greater lignin and total soluble phenol contents and greater induction of POX and SOD activity in inoculated plants in the region near the inoculation (position one) indicate local activation with later signalling for activation of defence mechanisms in other regions of the plant. The genotype with a greater level of resistance was superior to the susceptible one in regard to lignin production and the activities of POX, APX and SOD defence enzymes. These results suggest that a combination of these defence responses in common bean may contribute to greater plant resistance to the pathogen and that these enzymes have potential use in selection of common bean genotypes.     

Occurrence of Groundnut ringspot virus on Brazilian peanut crops

A high incidence of plants with mosaic, chlorotic spots, ringspots, necrosis, smaller leaves, and stunting was observed on peanut crops (Arachis hypogaea L.) in Itápolis, São Paulo State, Brazil. Transmission electron microscope examination of thin sections of infected leaves revealed the presence of spheroidal particles, ca. 80 nm in diameter, suggestive of Tospovirus. A DNA fragment of ~600 bp was amplified by RT-PCR from total RNA extracted from infected tissues using primers specific for the nucleocapsid gene of Groundnut ringspot virus (GRSV). Nucleotide and deduced amino acid sequences of the fragments showed high identities with known GRSV isolates.     

Expression of oestrogen and progesterone receptors in canine sebaceous gland tumours

Sebaceous gland oestrogen α (ERα) and progesterone (PR) receptor expression was examined immunohistochemically in 26 and 32 dogs respectively with sebaceous gland hyperplasia/adenomas, epitheliomas and carcinomas, and in the glands of 10 healthy controls. The mean percentage of ERα positive nuclei in control sebaceous glands was 21.31% compared with 11.5% in hyperplasia/adenoma‐type lesions, although these values were not statistically different. In sebaceous gland epitheliomas and carcinomas, positive basal cells represented 7.86% and 3.53% of neoplastic cells respectively and these mean percentages were significantly lower in epitheliomas (P < 0.024) and carcinomas (P < 0.015) than in controls. The mean percentage of PR‐positive nuclei in control sebaceous glands was 23.96%, similar to the 22.07% found in hyperplasia/adenoma‐type lesions. In sebaceous gland epitheliomas and carcinomas, positive cells were scarce and represented 13.5% and 4.06% of neoplastic cells respectively. Differences in the percentage of positive cells between normal and pathological glands reached statistical significance for carcinomas (P < 0.043). In the control group there was greater PR (P < 0.001) and ERα expression (P < 0.014) in sebaceous glands in female dogs. The PR and ERα immunoreactivity in each category of neoplastic lesions could not be analysed because sample size was too small but when all the sebaceous gland tumours were grouped and analysed, no sex difference was found. The results suggest that oestrogen and progesterone receptor expression is reduced in some canine sebaceous gland tumours. These changes may represent a contributing factor for tumour growth or simply be a consequence of tumour progression.     

Isolation and use of beneficial microbiota from the digestive tract of lions‐paw scallop Nodipecten subnodosus and winged pearl oyster Pteria sterna in oyster aquaculture

We isolated microbiota from the digestive tract of Nodipecten subnodosus and Pteria sterna and determined in vitro their haemolytic activity, antagonism against Vibrio spp., bacterial hydrophobicity, production of extracellular enzymes and molecular identification. Five bacterial strains were selected: RL5 and C3 (Lactobacillus spp.) and PB1‐1, PB1‐5 and PB1‐6 (Bacillus spp.). The RL5 and C3 isolates showed antimicrobial activity against Vibrio spp. and the PB1‐1, PB1‐5 and PB1‐6 isolates showed enzymatic activity for amylase, protease, lipase and cellulose; the C3 and PB1‐5 isolates were highly hydrophobic. The selected strains of bacteria were tested in vivo as probiotics, together with a treatment of ampicillin and a control without bacteria on juvenile Kumamoto oysters Crassostrea sikamea. The strains were provided individually and as mixes of isolates. Survival, growth and biochemical composition of the juveniles were determined as in vivo indicators. Juveniles grew significantly larger and faster when treated with a specific mix of isolates (MIX‐B), compared with the control. The protein, lipid and carbohydrate concentrations were also significantly higher in oysters exposed to probiotic treatments, compared with the control and the antibiotic treatment. The selected microbiota showed probiotic proprieties for cultivating C. sikamea juveniles.