1,720,965 research outputs found
Processi rigenerativi negli anellidi policheti Sabella spallanzanii Gmelin e Branchiomma luctuosum Grube (Sabellidae)
No full text
Benthic assemblage of Acquatina Lake (South Adriatic Sea): present state and long-term faunistic changes
Full text linkA study on macrobenthos of Acquatina Lake, a transitional water basin, was performed in order to evaluate its present status and detect any faunistic changes after the digging of a larger connection with the open sea that has improved the hydrological conditions. A total of 5029 individuals belonging to 51 taxa were collected. Molluscs were taxonomically the richest group, but polychaetes were the most abundant due to the high abundance of Heteromastus filiformis. The sites representing two extremes of the biotope in terms of both the salinity gradient and the distance from the sea had the most variable assemblages, while the central area showed a more homogeneous faunal composition. This was due to the different distribution patterns of molluscs and polychaetes: the former seemed to be more influenced by salinity, while the latter were also influenced by oxygen saturation. The comparison between the present and historical data showed the increase of polychaete diversity, the change in the dominant taxa (from Naineris laevigata to H. filiformis) and the disappearance of some opportunistic forms (e.g. Capitella capitata). Changes in the salinity gradient and the improvement of trophic conditions, possibly enhanced by biotic interactions (e.g. possible competition between the two capitellids H. filiformis and Notomastus latericeus), may have led the polychaete assemblage towards the new equilibrium
Il muco di Sabella spallanzanii (Annelida, Polychaeta): una protezione chimica e meccanica
No full textRole of Myxicola infundibulum (Polychaeta, Annelida) mucus: From bacterial control to nutritional home site.
Full text linkThe polychaete Myxicola infundibulum (Renier) produces a large amount of dense mucus which forms a gelatinous envelope where the worm lives. In the present study we evaluated some of the physical-chemical properties of this matrix such as viscosity, osmolarity, electrical conductivity, and protein, carbohydrate and total lipid content The presence of an antibacterial lysozyme-like activity as well as the density of culturable bacteria at 22 degrees C and vibrios and associated macrofauna were also investigated. The water content of M. infundibulum mucus was 95 +/- 0.5%. By dry weight, 38 +/- 1.2% was protein, 2 +/- 021% was carbohydrate and only 3% was lipid. Most of the remainder of the dry weight (about 57%) was inorganic. The mucus of M. infundibulum exerted a lysozyme-like activity evidenced on Petri dishes inoculated with Micrococcus luteus cell walls with a diameter of lysis of 8.4 +/- 0.3 mm, corresponding to 1.15 mg ml(-1) of hen egg white lysozyme. Notwithstanding this high antibacterial activity, the mucous tubes of M. infundibulum contained a high density of culturable heterotrophic bacteria at 22 degrees C, of which presumptive culturable vibrios accounted for 4.6 +/- 0.2 x 10(3) CPU ml(-1). Moreover, tubes were found to be colonized by several specimens of the polychaete Lumbrineris cfr. latreilli. Therefore the mucus of M. infundibutum appears to provide defence against some bacteria and food supply for the growth of others, that in turn could be utilized by macrofaunal organisms. On account of these features this matrix represents an accessible and renewable resource that could repay further exploration from several points of view
The mucus of Sabella spallanzanii (Annelida, Polychaeta): Its involvement in chemical defence and fertilization success
Full text linkn several species mucus typically forms a slippery coating that performs many specialised roles including the defence against infection and protection for eggs. In the present study we focused on the mucus of the polychaete Sabella spallanzanii in order to ascertain its involvement in chemical defence and fertilization success. The observations were carried out over an annual cycle according to different phases of the reproductive cycle. Mucus of S. spallanzanii showed a natural lysozyme-like activity with a maximum at pH 6.0 and I = 0.175. This activity was present in all the sampling times except for January (T-4) which corresponds to the reproductive period of this species. The electrophoretic analysis revealed at least ten major protein bands, with molecular weights ranging from 16 to 90 kDa, and six minor components, with molecular weights ranging from 14 to 116 kDa. This pattern was reported all over the year except for the reproductive period when not only the lysozyme-like activity decreased but the number of protein bands was also reduced. During this period microscopical observations of the mucus indicated that only fertilised eggs enveloped in the mucus were released out of the tubes where the worms live. This supports previous hypothesis that fertilization does not occur in the water column but it takes place in the tube just after egg release (in situ fertilization). This fertilization strategy, not involving egg dispersal in the water column, ensures a high success of fertilization. The mucus of S. spallanzanii therefore represents the ideal mean where eggs are released and fertilized as well as a compartment involved in defending the worms from bacterial attack serving as medium into which the antibacterial substances are exuded. The defensive role of lysozyme is important taking into account that this polychaete lives in eutrophic environments such as harbours where bacteria, including pathogens to man and marine organism, are abundant
Il Macrozoobenthos
Full text linkEnMacrobenthic samples were collected in 4 sites inside the Acquatina lake (3 replicates for each site in two times: July 2006 and January 2007). A total of 5029 individuals belonging to 50 taxa were found, with molluscs taxonomically dominant (26 taxa), followed by polychaetes (19 taxa), which was instead numerically dominant due to the massive presence of the species Heteromastus filiformis. Data were analysed by multivariate techniques. The assemblage was quite homogeneous within the lake, with more quantitative than qualitative differences among sites. Statistical analysis showed two sites, representing the two extreme of the biotope condition, as the most variable ones and separated from the others, located in the middle of the investigated biotope. The separation of the two sites from this central more homogeneous area was due to a different distribution between molluscs and polychaetes species. The comparison of the polychaete distribution between data relative to a previous period of study and present ones revealed a more diversified assemblage, with the disappearance of some opportunistic forms, and with an homogenization within the basin, underlining the disappearance of the strong salinity gradient
Bioremediation of bacteria in aquaculture waste using the polychaete Sabella spallanzanii
Full text linkThe excessive release of bacterial pathogens from animal waste into the aquaculture environment has
become a major concern for the aquaculture industry. The biological filtration by macroinvertebrates
contributes to water purification as a result of the bacterioplankton removal from the water. The filterfeeder
polychaete Sabella spallanzanii is known for its ability to accumulate bacteria from the marine
environment. In the present study we evaluated the survival, growth and capability of this species to
remove several bacterial groups from aquaculture waste in order to ascertain its employment as
bioremediator in a farming scenario coupled with the conversion of the wastes into polychaete proteinrich
biomass of potentially marketable value. In comparison to other technologies, the employment of
S. spallanzanii in waste treatment represents a more attractive option to reduce bacterial loads
Accrescimento del polichete Sabella spallanzani (Annelida, Sabellidae) in un impianto di acquacoltura in-shore
No full textFirst insights into the biochemistry of Sabella spallanzanii (Annelida: Polychaeta) mucus: a potentially unexplored resource for applicative purposes
Full text linkAlthough mucus plays many different roles among marine invertebrates, relatively little is known about the link between biochemical structure and function. In the present study we focused on some physical and chemical properties of the polychaete Sabella spallanzanii's mucus such as viscosity, osmolarity, electrical conductivity, elemental composition, the protein and carbohydrate content, the total lipids and fatty acid composition, and polychlorinated biphenyls (PCBs) contamination. Moreover, an antimicrobial activity of the mucus was investigated. The water content of S. spallanzanii mucus was 96.2 +/- 0.3%. By dry weight 26 +/- 1.2% was protein, 8 +/- 0.21% was carbohydrate and only 0.1% lipid, much of the remainder of the dry weight was inorganic (about 65.2%). The estimated PCBs content was <0.005 mu g g(-1). The mucus of S. spallanzanii exerted a natural lysozyme-like activity and produced in vitro the growth inhibition of Vibrio anguillarum, Vibrio harveyi, Pseudomonas aeruginosa and Candida albicans. The findings from this study contribute to improve the limited knowledge available on the mucus composition in invertebrates and have implications for future investigations related to employment of S. spallanzanii mucus as a source of compounds of pharmaceutical and marine technological interest
- …
