Environmental Conditioning of Skeletal Anomalies Typology and Frequency in Gilthead Seabream (Sparus aurata L., 1758) Juveniles

In this paper, 981 reared juveniles of gilthead seabream (Sparus aurata) were analysed, 721 of which were from a commercial hatchery located in Northern Italy (Venice, Italy) and 260 from the Hellenic Center for Marine Research (Crete, Greece). These individuals were from 4 different egg batches, for a total of 10 different lots. Each egg batch was split into two lots after hatching, and reared with two different methodologies: intensive and semi-intensive. All fish were subjected to processing for skeletal anomaly and meristic count analysis. The aims involved: (1) quantitatively and qualitatively analyzing whether differences in skeletal elements arise between siblings and, if so, what they are; (2) investigating if any skeletal bone tissue/ossification is specifically affected by changing environmental rearing conditions; and (3) contributing to the identification of the best practices for gilthead seabream larval rearing in order to lower the deformity rates, without selections. The results obtained in this study highlighted that: i) in all the semi-intensive lots, the bones having intramembranous ossification showed a consistently lower incidence of anomalies; ii) the same clear pattern was not observed in the skeletal elements whose ossification process requires a cartilaginous precursor. It is thus possible to ameliorate the morphological quality (by reducing the incidence of severe skeletal anomalies and the variability in meristic counts of dermal bones) of reared seabream juveniles by lowering the stocking densities (maximum 16 larvae/L) and increasing the volume of the hatchery rearing tanks (minimum 40 m³). Feeding larvae with a wide variety of live (wild) preys seems further to improve juvenile skeletal quality. Additionally, analysis of the morphological quality of juveniles reared under two different semi-intensive conditions, Mesocosm and Large Volumes, highlighted a somewhat greater capacity of Large Volumes to significantly augment the gap with siblings reared in intensive (conventional) modality.     

A new lipophilic fluorescent probe for interaction studies of bioactive lipopeptides with membrane models

The new fluorescent lipophilic moiety 11-[(7-amino-4-methyl-2-oxo-2H-1-benzopyran-3-acetyl)amino]undecanoic acid (AMCA-omegaAud-OH) was introduced by SPPS at the N-terminus of the immunodominant epitope GpMBP(74-85). FRET experiments using the new fluorescent lipopeptide demonstrate that the peptide interacts with much more affinity with the membrane compared to the lipid free analogue.     

Phospholipid Remodeling and Cholesterol Availability Regulate Intestinal Stemness and Tumorigenesis

1. Download high-res image (219KB)
2. Download full-size image

     

1H nuclear magnetic relaxation dispersion of Cu,Zn superoxide dismutase in the native and guanidinium-induced unfolded forms

Potentialities and limitations of the use of (1)H NMRD technique for the characterization of the hydration properties of unfolded or partially folded states of proteins are discussed. The copper(I) form of monomeric Cu,Zn superoxide dismutase in its folded state and in the presence of 4M guanidinium chloride is taken as case system. The dispersion profile, analyzed with an extended relaxation matrix analysis, indicates the presence of long-lived water molecules in the folded state. The observed increase in relaxation at high field upon addition of guanidinium chloride indicates an increase in the number of solvation protons interacting with the protein and exchanging with a time shorter than the protein reorientational time. The observed effect is consistent with an exposed protein surface of SOD in the presence of 4M guanidinium chloride smaller than what could be expected for a random coil.     

The first cytoplasmic loop of the mannitol permease from Escherichia coli is accessible for sulfhydryl reagents from the periplasmic side of the membrane

The mannitol permease (EII(Mtl)) from Escherichia coli couples mannitol transport to phosphorylation of the substrate. Renewed topology prediction of the membrane-embedded C domain suggested that EII(Mtl) contains more membrane-embedded segments than the six proposed previously on the basis of a PhoA fusion study. Cysteine accessibility was used to confirm this notion. Since cysteine 384 in the cytoplasmic B domain is crucial for the phosphorylation activity of EII(Mtl), all cysteine mutants contained this activity-linked cysteine residue in addition to those introduced for probing the membrane topology of the protein. To distinguish between the activity-linked cysteine and the probed cysteine, either trypsin was used to specifically digest the two cytoplasmic domains (A and B), thereby removing Cys384, or Cys384 was protected by phosphorylation from alkylation by N-ethylmaleimide (NEM). Our data show that upon phosphorylation EII(Mtl) undergoes major conformational changes, whereby residues in the putative first cytoplasmic loop become accessible to NEM. Other residues in this loop were accessible to NEM in intact cells and inside-out membrane vesicles, but cysteine residues at these positions only reacted with the membrane-impermeable sulfhydryl reagent from the periplasmic side of the protein. These and other results suggest that the predicted loop between TM2 and TM3 may fold back into the membrane and form part of the translocation path.