Genetic diversity of durum wheat as determined by AFLP in fluorescence

The DNA of fifteen Italian cultivars of durum wheat (Triticum turgidum L. ssp. durum) were analyzed by in fluorescence amplified fragment length polymorphism (fAFLP) in order to obtain the characteristic fingerprintings of genotypes and assess their genetic relatedness. Among 64 combinations of fluorescence labelled primers, three different combinations were chosen as producing a total of 6630 AFLP fragments, 2277 (34.3 %) of them being polymorphic. By using this fAFLP methodology a DNA fingerprinting of each durum wheat cultivar was generated for genotype identification. Analysis of the genetic relationships show the low variability among durum wheat cultivars.     

Continuous measurement of minute ventilation and gaseous metabolism of newborn infants

A system of instrumentation for continuous measurement of gaseous metabolism and minute volume (VI) in the human newborn is described. O2 uptake and CO2 production are measured by open-circuit techniques utilizing a Servomex OA184 differential paramagnetic O2 analyzer and a BEckman LB-2 infrared CO2 analyzer. VI is measured with bias-flow pneumotachometry. Bench performance is described, methodological errors are defined, and clinical data are presented. The instrumentation is capable of safe, accurate, and continuous measurement of respiratory and metabolic variables in low-birth-weight infants.     

Insulin receptor isoform A, a newly recognized, high-affinity insulin-like growth factor II receptor in fetal and cancer cells

Insulin-like growth factor II (IGF-II) is a peptide growth factor that is homologous to both insulin-like growth factor I (IGF-I) and insulin and plays an important role in embryonic development and carcinogenesis. IGF-II is believed to mediate its cellular signaling via the transmembrane tyrosine kinase type 1 insulin-like growth factor receptor (IGF-I-R), which is also the receptor for IGF-I. Earlier studies with both cultured cells and transgenic mice, however, have suggested that in the embryo the insulin receptor (IR) may also be a receptor for IGF-II. In most cells and tissues, IR binds IGF-II with relatively low affinity. The IR is expressed in two isoforms (IR-A and IR-B) differing by 12 amino acids due to the alternative splicing of exon 11. In the present study we found that IR-A but not IR-B bound IGF-II with an affinity close to that of insulin. Moreover, IGF-II bound to IR-A with an affinity equal to that of IGF-II binding to the IGF-I-R. Activation of IR-A by insulin led primarily to metabolic effects, whereas activation of IR-A by IGF-II led primarily to mitogenic effects. These differences in the biological effects of IR-A when activated by either IGF-II or insulin were associated with differential recruitment and activation of intracellular substrates. IR-A was preferentially expressed in fetal cells such as fetal fibroblasts, muscle, liver and kidney and had a relatively increased proportion of isoform A. IR-A expression was also increased in several tumors including those of the breast and colon. These data indicate, therefore, that there are two receptors for IGF-II, both IGF-I-R and IR-A. Further, they suggest that interaction of IGF-II with IR-A may play a role both in fetal growth and cancer biology.     

Plasma endothelin-1 levels and albumin excretion rate in normotensive,microalbuminuric type 2 diabetic patients

BACKGROUND: Endothelin-1 (ET-1) is able to determine functional and structural renal alterations and plasma levels of this vasoconstrictor peptide are increased in diabetic patients. In a selected group of type 2 normotensive diabetic patients with microalbuminuria, we investigated circulating ET-1 levels compared to a control group and verified whether there is a relationship between ET-1 levels and albumin excretion rate in diabetics. SUBJECTS AND METHODS: Thirty-two microalbuminuric type 2 diabetic patients (12 males and 20 females; mean age 57 +/- 8 years) without hypertension, renal failure, hypercholesterolemia or atherosclerotic damage were selected. The control group was made up of 28 healthy subjects matched for sex and age. Blood pressure, creatinine clearance, serum cholesterol and plasma ET-1 values were determined in diabetic and control group. In diabetic patients, glycosilated hemoglobin and urinary albumin excretion rate were also assayed. Mean ET-1 values in diabetics and controls were compared using Student's t-test. Linear regression test was done to relate two variables. Statistical significance was set at p<0.05. RESULTS: Mean ET-1 values were significantly higher in the diabetic group than in controls (11.77 +/- 1.16 pg/ml vs 8.9 +/- 2.1 pg/ml; p<0.05). No relationship (p>0.05) was found between circulating ET-1 and blood pressure, creatinine clearance, serum cholesterol and metabolic control in diabetics. There was a significant positive correlation (r=0.403; p=0.03) between plasma ET-1 levels and albumin excretion rate in diabetic patients. CONCLUSIONS: Our results showed that circulating ET-1 values were increased in microalbuminuric, normotensive, type 2 diabetic patients and correlated with albumin excretion rate. These findings confirm that endothelial dysfunction, as expressed by ET-1 levels, occurs early in these patients and support the hypothesis of a potential role for this peptide in development of microalbuminuria in diabetic nephropathy.     

Annual Acoustic Presence of Fin Whale (Balaenoptera physalus) Offshore Eastern Sicily,Central Mediterranean Sea

In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, “NEMO-SN1”, deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz–1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9–22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise.     

Role of c-Abl in directing metabolic versus mitogenic effects in insulin receptor signaling

c-Abl is a cytoplasmic tyrosine kinase involved in several signal transduction pathways. Here we report that c-Abl is involved also in insulin receptor signaling. Indeed, c-Abl tyrosine kinase is activated upon insulin stimulation. Inhibition of c-Abl tyrosine kinase by STI571 attenuates the effect of insulin on Akt/GSK-3beta phosphorylation and glycogen synthesis, and at the same time, it enhances the effect of insulin on ERK activation, cell proliferation, and migration. This effect of STI571 is specific to c-Abl inhibition, because it does not occur in Abl-null cells and is restored in c-Abl-reconstituted cells. Numerous evidences suggest that focal adhesion kinase (FAK) is involved in mediating this c-Abl effect. First, anti-phosphotyrosine blots indicate that c-Abl tyrosine kinase activation is concomitant with FAK dephosphorylation in response to insulin, whereas c-Abl inhibition is accompanied by FAK phosphorylation in response to insulin, a response similar to that observed with IGF-I. Second, the c-Abl effects on insulin signaling are not observed in cells devoid of FAK (FAK(-/-) cells). Taken together these results suggest that c-Abl activation by insulin, via a modification of FAK response, may play an important role in directing mitogenic versus metabolic insulin receptor signaling.     

Insulin receptor isoforms are differently expressed during human osteoblastogenesis

The reciprocal influence and bidirectional cross-talk between bone and energy metabolism is a recent finding, since the discovery that the product of osteoblasts osteocalcin increases pancreatic β-cell proliferation, insulin secretion and sensitivity. Conversely, the anabolic effect of insulin is crucial for osteoblast function, as suggested by severe osteopenia and increased incidence of fracture in insulin-deficient diabetic patients. The Insulin Receptor (IR) tyrosine kinase, which is commonly expressed in the insulin-sensitive liver, muscle, and adipose tissues, is also found in animal and human bone. Here we show that in human bone two insulin receptor isoforms (IR-A and IR-B) are differently expressed. Mature human osteoblasts predominantly express IR-B, whereas IR-A is mainly expressed in osteoblast precursors, and IR-B/IR-A mRNA ratio significantly increases along the osteogenic differentiation of mesenchymal stromal precursors. Moreover, transfected osteoprogenitors overexpressing IR-A show an increased proliferation rate. In contrast, when transfected with and overexpressing IR-B, their proliferation rate is reduced, corresponding to a more differentiated phenotype. In conclusion, the fine regulation of the expression of different isoforms of IR during osteogenic differentiation confirms the important role played by IR in bone homeostasis, providing the basis for new perspectives on the various involvements of IR isoforms in bone pathophysiology.     

Calcium-activated membrane interaction of the islet amyloid polypeptide: implications in the pathogenesis of type II diabetes mellitus

The role played by Ca²⁺ ions in the interaction of the human islet amyloid polypeptide (hIAPP) with model membranes has been investigated by differential scanning calorimetry (DSC) and circular dichroism (CD) experiments. In particular, the interaction of hIAPP and its rat isoform (rIAPP) with zwitterionic dipalmitoyl-phosphatidylcholine (DPPC), negatively charged dipalmitoyl-phosphatidylserine (DPPS) vesicles and with a 3:1 mixtures of them, has been studied in the presence of Ca²⁺ ions. The experiments have evidenced that amorphous, soluble hIAPP assemblies interact with the hydrophobic core of DPPC bilayers. Conversely, the presence of Ca²⁺ ions is necessary to activate a preferential interaction of hIAPP with the hydrophobic core of DPPS membranes. These findings support the hypothesis that an impaired cellular homeostasis of Ca²⁺ ions may promote the insertion of hIAPP into the hydrophobic core of carrier vesicles which is thought to contribute to an eventual intracellular accumulation of β-sheet rich hIAPP aggregates.     

Ab initio molecular dynamics of the reactivity of vitamin C toward hydroxyl and $$ {HO}_2/{O}_2^{-} $$ radicals

Vitamin C is one of the most abundant exogenous antioxidants in the cell, and it is of the utmost importance to elucidate its mechanism of action against radicals. In this study, the reactivity of vitamin C toward OH and \( {HO}_2/{O}_2^{-} \) radicals in aqueous medium was analyzed by ab initio molecular dynamics using CPMD code. The simulations led to results similar to those of static studies or experiments for the pair of \( {HO}_2/{O}_2^{-} \) radicals but bring new insights for the reactivity with hydroxyl radical: the reaction takes place before the formation of an adduct and consists of two steps: first an electron is transferred to hydroxyl radical and then the ascorbyl radical loses a proton.

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Graphical Abstract Reactivity of vitamin C toward hydroxyl and \( {HO}_2/{O}_2^{-} \) radicals