Letterio Guglielmo

Ross Sea Ecology

Italian research on Antarctic atmosphere started in a systematic way in 1986 when the Programma Nazionale di Ricerche in Antartide began its activity. Studies on the atmosphere have been developed in five different projects: planetary boundary layer physics; meteorology and climatology; aerosols radiation and clouds; minor components and greenhouse gases; physics and chemistry of the stratosphere. The monitoring activity has been developed considering two different aspects: (1) the need to have continuous and reliable measurements of the meteorological parameters in the area of the Italian base and (2) the possibility to carry out some specific studies concerning the physics, the dynamics and chemistry of the atmosphere. A climatological observatory has been arranged with a network of fixed automatic weather stations, that record meteorological data throughout the year. During the summer upper level soundings are also conducted. In the present chapter the climatological data, collected in about a decade,are analyzed to give a climatic picture of Terra Nova Bay. The parameters considered are radiation, pressure, temperature, humidity and wind. The obtained results have been compared, when possible, with the data collected at foreign stations, to verify their reliability. A short discussion about Antarctica and climate change closes the work.

Day/night vertical distribution of euphausiids in the eastern tropical Pacific

Between March 23 and April 4, 1981, samples were taken in the eastern tropical Pacific. The day/night vertical distribution of euphausiid species and biomass are described and contrasted in detail on two eastern tropical Pacific stations, the DOME station, in a region of continuous upwelling and the BIOSTAT station, in a nonupwelling area. The effects of various biological parameters, such as temperature, salinity and oxygen concentrations on the distributions of the species are examined. The numbers of euphausiids m-2 on both stations were highest during the day, indicating that avoidance of the sampler was not a problem. During the day the largest concentration of adult euphausiids was between 300 and 350 m whereas the juveniles were concentrated between 170 and 80 m on both stations. Very few individuals were found within the oxygen minimum layer, but low concentrations of some species were found below the oxygen minimum down to 1 000 m. At night the euphausiid concentration migrated upward into the mixed layer (20 to 30 m) at BIOSTAT and to the base of the mixed layer at the DOME. Significant differences in the night depths of the species were found on both stations. The oxygen minimum layer appeared to act as a barrier to the vertical distribution of all species. Only two species were found in water with an oxygen concentration of <0.1 ml O2 l-1. Twentyone species of euphausiids were found on the two stations but the adult population was dominated by only two or three species on both stations. The reproductive state of the species suggested that some species reproduced earlier on the DOME than on BIOSTAT. Analysis of the depth distribution by cluster analysis showed that the most abundant species occupied different depths during the night and day at BIOSTAT but the two most abundant species were concentrated at the same depth at the DOME station although portions of each species population occupied different pelagic zones.

Curcumin ameliorates the in vitro efficacy of carfilzomib in human multiple myeloma U266 cells targeting p53 and NF-κB pathways

Multiple myeloma (MM) is a malignant B-cell neoplasm with accumulation of malignant plasma cells in bone marrow. Pharmacological therapy improves response frequency even if with various associated toxicities. Herein, we investigated if combination of curcumin with carfilzomib (CFZ) can induce a better cytotoxic effect on in vitro cultured U266 cells. Cell viability data showed that curcumin significantly ameliorates CFZ cytotoxic effect. Furthermore, curcumin alone did not affect proteasome at the tested dose, confirming the involvement of different mechanisms in the observed effects. U266 cells exposure to curcumin or CFZ increased reactive species (RS) levels, although their production did not appear further potentiated following drugs combination. Interestingly, NF-κB nuclear accumulation was reduced by treatment with CFZ or curcumin, and was more deeply decreased in cells treated with CFZ-curcumin combinations, very likely due to the different mechanisms through which they target NF-κB. Our results confirmed the induction of p53/p21 axis and G0/G1 cell cycle arrest in anticancer activities of both drugs, an effect more pronounced for the CFZ-curcumin tested combinations. Furthermore, curcumin addition enhanced CFZ proapoptotic effect. These findings evidence that curcumin can ameliorate CFZ efficacy, and lead us to hypothesize that this effect might be useful to optimize CFZ therapy in MM patients.

The Italian Oceanographic Cruises in the Ross Sea (1987–95): Strategy, General Considerations and Description of the Sampling Sites

The Antarctic has often been considered a paradox in terms of primary productivity. That is, the rich water masses in this region, with their elevated nutrient concentrations, are rarely matched by correspondingly high phytoplankton standing stocks and productivity. Exceptions to this general condition are the productive coastal areas and frontal systems that are considered as productive as most regions in temperate latitudes. The Ross Sea may be another exception to this general scenario of low plankton productivity. As of the early 1980s, there has been increasing evidence that this area may represent one of the most productive regions in the Antarctic. Elevated phytoplankton biomass and productivity have, in fact, been measured both in situ (Smith and Nelson 1985; Wilson et al. 1986; Innamorati et al. 1990, 1992; Smith et al. 1996; Saggiomo et al. 1998; Lazzara et al., this Vol.) and via satellite images (Arrigo and McClain 1994). Further, there is also evidence of elevated flux of biogenic material accumulated over the continental shelf (Dunbar et al. 1985; DeMaster et al. 1992; Fabiano et al. 1996; Nelson et al. 1996; Langone et al. 1997; Ceccaroni et al. 1998; Frignani et al., this Vol.). The elevated productivity of this region has also recently been confirmed for its top predators such as krill, birds, seals and whales (Saino and Guglielmo, this Vol.; Azzali et al., this Vol.).

Diagnostic value of the thelycum in euphausiids. II. Oceanic species, genus Nematoscelis

The thelycum morphology of 7 species of the genus Nematoscelis, based upon observations with the scanning electron microscope, is described. The thelycum of N. megalops and N. difficilis did not differ either with respect to general morphology of the thelycum, or in spermatophore insertion. In the other 5 species, N. tenella, N. gracilis, N. atlantica, N. lobata, N. microps, the main thelycum structure consists of a central lobe of various forms, to which a filamentous spermatic mass is attached. Preliminary observations on the position of the genital pores of two species are reported briefly.

Spring and autumn spatial distribution of zooplankton carbon requirement across the Mediterranean Sea

ABSTRACT Zooplankton represents a key contributor to the ocean biological pump through its consumption of sinking and suspended carbon. A specific and highly sensitive method to evaluate zooplankton carbon requirement from the sinking flux is through the estimation of the activity of the electron transport system. The present study was carried out from samplings in 2006, and it was focused on the spatial 200–0u2005m zooplankton carbon demand across 24 sampling stations, along the Mediterranean Sea, from the island of Crete to the Strait of Gibraltar. Its potential day/night variability was evaluated. The zooplankton composition, abundance and biomass were investigated. The carbon demand per unit zooplankton biomass indicates geographical and diel differences among the sampling stations. A higher mean carbon demand was seen for the western Mediterranean with respect to the eastern Mediterranean, which can be justified through the observed ratio of gelatinous:crustacean taxa and the water temperatures recorded. Higher carbon demand was measured in samples collected during the dark hours. The relation to the presence and abundance of actively migrating euphausiids and copepods was discussed. A comparison with data from another of our study carried out in the same study area but in another seasonal period was done.

Biogeographical Features of the Study Area

The study area lies within the geographical range of the so-called antiboreal South American (Eckman 1953), Magellanic (Balech 1954; Schilder 1956; Briggs 1974) or Magellanean (Antezana 1981) Province which extends from 42°S to the Antarctic Convergence along the channels of western South America, around its tip to Peninsula Valdes and along the east coast of South America, including the Falkland (Malvinas) Islands. The northern limits and districts of this Province, on the Pacific side, are not well established, according to authors who have studied the littoral (Hedgpeth 1969) and pelagic (Antezana 1981) faunas in this area. Based on the littoral fauna, Balech (1954) distinguished two districts: the chiloensis from 41°S to 51°S and the fuegensis from 51°S to the tip of South America. Antezana (op. cit.) recognized these two districts for the pelagic fauna as well, but proposed boundaries from 42–47°S and 47–60°S.