Histopathological findings in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with 3 different Aeromonas species

This study describes the macroscopic and microscopic lesions in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with genetically identified Aeromonas salmonicida, A. hydrophila, and A. veronii species. The genus Aeromonas includes bacteria that naturally inhabit both waterways and organisms. At least 27 Aeromonas species have been identified to date, some of which can cause significant economic losses in aquaculture. As up to 68.8% of Aeromonas isolates may be misidentified in routine biochemical and phenotypic tests, however, reported cases of Aeromonas infection in fish may be wrongly identified. Our findings confirmed that the 3 Aeromonas species studied are associated with septicemia and dermal lesions in rainbow trout.     

Comparison of three types of adhesives in attaching coral transplants to clam shell substrates

• 1. Nubbins from 12 coral species were transplanted onto dead giant clam shells at three sites in a lagoon near Bolinao, north‐western Philippines. Transplants were attached using three types of adhesives: cyanoacrylate glue (SG), epoxy putty (EP) and marine epoxy (ME) and were monitored over five months for detachment, in situ mortality and natural self‐attachment by tissue growth.
• 2. Corals attached with SG showed a significantly higher rate of detachment (logrank test) than those attached with either EP or ME (P<0.001 in each case). Also, those attached with EP showed a higher rate of detachment than corals attached with ME (logrank=6.46, P<0.05).
• 3. ANOVA (P>0.05) and survival analysis (logrank=2.85, P>0.05) showed no among‐adhesives differences in in situ mortality. Among the species used, Porites cylindrica, Pavona frondifera, Heliopora coerulea and Porites rus had the highest survivorship with 82%, 80%, 76% and 73%, respectively, of nubbins alive at the end of the experiment and also displayed the highest cumulative rates of self‐attachment. Species with the lowest survival rates included Acropora muricata and four pocilloporids.
• 4. Although there was no significant difference in the number of self‐attaching transplants among the adhesives, corals transplanted using ME and EP self‐attached earlier than those transplanted using SG (logrank=11.19, P<0.01).
• 5. Results from this study highlight the importance of selecting the appropriate means of attaching corals to substrates and carefully considering species‐specific traits of candidate corals for transplantation.

Copyright © 2008 John Wiley & Sons, Ltd.     

Brucella intracellular life: from invasion to intracellular replication

Brucella organisms are pathogens that ultimate goal is to propagate in their preferred niche, the cell. Upon cell contact the bacteria is internalized via receptor molecules by activating small GTPases of the Rho subfamily and by a moderate recruitment of actin filaments. Once inside cells, Brucella localizes in early phagosomes, where it avoids fusion with late endosomes and lysosomes. These early events require the control of Rab small GTPases, and cytokines such as the G-CSF. Then, the bacterium redirects its trafficking to autophagosomes and finally reaches the endoplasmic reticulum, where it extensively replicates. Some of the bacterial molecular determinants involved in the internalization and early events after ingestion are controlled by the BvrS/BvrR two component regulatory system, whereas the intracellular trafficking beyond this early compartments are controlled by the VirB type IV secretion system. Once inside the endoplasmic reticulum, Brucella extensively replicates without restricting basic cellular functions or inducing obvious damage to cells. The integrity of Brucella LPS on the bacterial surface is one of the required factors for Brucella intracellular survival, and therefore for virulence.     

Seasonal Variations of Sulphate Reduction Rates, Sulphur Pools and Iron Availability in the Sediment of a Dystrophic Lagoon (Sacca di Goro, Italy)

The aim of this work was to analyse factors which regulate sulphide mobility in the sediments of a dystrophic lagoon (Sacca di Goro, the southern lagoon of the Po river delta, Italy). In 1995-96, sediment oxygen demand and variations in organic matter content, redox potential, iron availability, inorganic sulphur concentrations and sulphate reduction rates were measured in sediment profiles at three stations (G, 4 and 17) representative of the main areas of the lagoon. Stations differed mainly in their salinity range and primary producer communities. High concentrations of reactive iron (110-275 µmol ml-1) and low sulphate reduction rates (0.8-16.1 mmol m-2 d-1) were measured in the sediment. Moreover, high concentrations of reactive ferric iron were detected in winter and spring at the stations closest to the freshwater inputs. Nevertheless, in summer, high concentrations of free sulphides were detected in the porewater, although most of the reactive ferrous iron was not sulphide-bound, indicating that not all of the reactive iron pool was available to buffer against sulphide release and thus measures of reactive iron pools may not be a good measure of the true buffering capacity of the sediment. Furthermore, a considerable production of sulphide may occur in the decaying Ulva biomass in the water column, where its concentration will be independent of the potential buffering capacity of iron in the sediment. Therefore when assessing the vulnerability of coastal lagoons to dystrophic events, both the size and availability of the reactive iron pool as well as the site of sulphide production must be taken into consideration.     

Typology in Mediterranean transitional waters: new challenges and perspectives

• 1. Transitional waters are ecotones between terrestrial, freshwater and marine ecosystems, being characterized by high spatial heterogeneity and temporal variability.
• 2. The EU Water Framework Directive (WFD) posed to the scientific community the challenge to classify these ecosystems into a small number of types, while retaining a functional classification of ecosystem types.
• 3. A niche theory approach is proposed to identify the limiting forcing factors organizing biological quality elements, i.e. the limiting niche dimensions.
• 4. The analysis of a macro‐invertebrate dataset from published papers on 36 Italian lagoons suggested a two‐level typological classification of Mediterranean lagoons.
• 5. Basic ecological theories, such as niche and island biogeography theories, have fundamental implications for the process of developing a typological classification for all aquatic ecosystems, as required by the WFD.

Copyright © 2006 John Wiley & Sons, Ltd.     

Relationship of European persimmon (Diospyros kaki Thunb.) cultivars to Asian cultivars, characterized using AFLPs

Sixty one persimmon (Diospyros kaki Thunb.) selections, including 17 Italian, 11 Spanish, 13 Japanese, six Korean, five Chinese, one Israeli, and eight of unknown origin, were evaluated for genetic differences by AFLP analysis. Relationships among cultivars were evaluated by UPGMA clustering, Neighbor Joining, and MultiDimensional Scaling. While similarities among groups were generally less than 0.60, both UPGMA and Neighbor Joining separated European and Asian cultivars. Spanish and Italian cultivars were not separated by any of the analyses, suggesting that they share a common gene pool, while Japanese, Chinese and Korean cultivars formed distinct clusters. Diversity within groups was greater than diversity between groups. Most cultivars were quite polymorphic (only 0.60–0.80 similarity between cultivars). In addition, the presence of several Japanese cultivars in the European group and a group of European cultivars nested between Chinese and Korean groups suggest that similar, but different progenitors were used in the development of the present European cultivars. ‘Kaki Tipo’ selections from different sources were clearly different by AFLP analysis, indicating that they are separate cultivars.     

Can mineral and organic fertilization help sequestrate carbon dioxide in cropland?

The soil organic matter content represents a huge reservoir of plant nutrients and an effective safeguard against pollution; beside it can sequestrate atmospheric CO₂. Since 1966 up to now in the Southeast Po valley (Italy), the soil organic C (SOC) and total N (TN) dynamics in the 0–0.40 m soil layer under a maize–wheat rainfed rotation are studied as influenced by organic and mineral N fertilizations. Every year in the same plots cattle manure, cattle slurry, and crop residues (i.e. wheat straw and maize stalk) are ploughed under to 0.40 m depth at a same dry matter rate (6.0 and 7.5 t DM ha⁻¹ year⁻¹ after wheat and maize, respectively) and are compared to an unamended control. Each plot is splitted to receive four rates of mineral fertilizer (0–100–200–300 kg N ha⁻¹). In the whole experiment, in 2000 SOC concentration was lower than in 1966 (6.77 and 7.72 g kg⁻¹, respectively), likely for the deeper tillage that diluted SOC and favoured mineralization in deeper soil layer. From 1972 to 2000 SOC stock did not change in the control and N fertilized plots, while it increased at mean rates of 0.16, 0.18, and 0.26 t ha⁻¹ year⁻¹ with the incorporation of residues, slurry and manure, corresponding to sequestration efficiencies of 3.7, 3.8 and 8.1% of added C with the various materials. TN followed the same SOC dynamic, demonstrating how it depends on the soil organic matter. Manure thus confirmed its efficacy in increasing both SOC content and soil fertility on the long-term. In developed countries, however, this material has become scarcely available; slurry management is expensive and implies high environmental risks. Moreover, in a C balance at a farm (or regional) scale, the CO₂ lost during manure and slurry stocking should be considered. For these reasons, the incorporation of cereal residues, even if only a little of their C content was found capable of soil accumulation, appears the best way to obtain a significant CO₂ sequestration in developed countries. Our long-term experiment clearly shows how difficult it is to modify SOC content. Moreover, because climate and soil type can greatly influence SOC dynamic, to increase CO₂ sequestration in cropland, it is important to optimize the fertilization within an agricultural management that includes all the agronomic practices (e.g. tillage, water management, cover crops, etc.) favouring the organic matter build up in the soil.     

Rough vaccines in animal brucellosis: structural and genetic basis and present status

Brucellosis control and eradication requires serological tests and vaccines. Effective classical vaccines (S19 in cattle and Rev 1 in small ruminants), however, induce antibodies to the O-polysaccharide of the lipopolysaccharide which may be difficult to distinguish from those resulting from infection and may thus complicate diagnosis. Rough attenuated mutants lack the O-polysaccharide and would solve this problem if eliciting protective immunity; the empirically obtained rough mutants 45/20 and RB51 have been used as vaccines. Strain 45/20 is reportedly unstable and it is not presently used. RB51 is increasingly used instead of S19 in some countries but it is rifampicin resistant and its effectiveness is controversial. Some controlled experiments have found good or absolute protection in adult cattle vaccinated orally (full dose) or subcutaneously (reduced dose) and in one field experiment, RB51 was reported to afford absolute protection to calves and to perform better than S19. Controlled experiments in calves, however, have shown reduced doses of RB51 to be ineffective, full doses only partially effective, and RB51 less effective than S19 against severe challenges. Moreover, other observations suggest that RB51 is ineffective when prevalence is high. RB51 is not useful in sheep and evidence in goats is preliminary and contradictory. Rough mutants obtained by molecular biology methods on the knowledge of the genetics and structure of Brucella lipopolysaccharide may offer alternatives. The B. abortus manBcore (rfbK) mutant seems promising in cattle, and analyses in mice suggest that mutations affecting only the O-polysaccharide result in better vaccines than those affecting both core and O-polysaccharide. Possible uses of rough vaccines also include boosting immunity by revaccination but solid evidence on its effectiveness, safety and practicality is not available.     

Glue barriers reduce earwig damage on apricots in north-western Italy

The European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), is a well-known species that is cosmopolitan and present throughout Europe. Due to its omnivorous feeding behaviour, this species can act as a generalist predator, preying on several top fruit pests, but also as a pest causing shallow gouges or holes in stone and soft fruits such as apricots, strawberries, raspberries or blackberries. In Piedmont (NW Italy), significant fruit damage has been observed lately in apricot orchards where earwigs fed on ripening fruits and made a considerable part of the produce unmarketable. In this study, we sampled earwig populations in three apricot orchards in Piedmont and tested the effectiveness of glue barriers applied to the tree trunks in reducing both earwig density in the canopy and fruit damage. The arboreal glues Rampastop® and Vebicolla® were tested both in the field and laboratory trials. Glue barriers demonstrated to be effective control measures, significantly reducing earwig abundance in the canopy and fruit damage. Rampastop® gave better results on old trees with a very rough and cracked bark, since in that case Vebicolla® could not perfectly bond with the trunk.     

Characterization of under-utilized fruits by molecular markers. A case study of loquat

The usefulness of RAPD markers for genotyping a minor fruit species such as loquat has been tested in order to assess their ability for identifying accessions and to provide a set of markers suitable for use by different groups of scientists and curators. Twenty-nine polymorphic markers selected from a previous study of 33 accessions were tested in 46 new accessions added to the collection. Using the same PCR standard conditions, only 20 markers out of 29 selected in the previous study gave consistent amplifications in the new set of plant material. The rest required optimization of reaction conditions. This fact pointed out that RAPD markers were sensitive to the experimental conditions, hence a standard technique did not guarantee reproducibility. To overcome this problem markers for plant fingerprinting should be selected after comparison across accession sets. Only those markers reproducible with different sampling and checked in several sets of accessions are suitable for germplasm fingerprinting. In the present study we propose 31 RAPDs for fingerprinting loquat that accomplished these characteristics.The markers obtained were sufficient for determining origin and relationships of cultivars, for identifying synonyms and derived varieties from bud-sports. All bud sports were identical for all RAPDs selected.