Divergent Effects of Short-Term,Very-Low-Calorie Diet on Insulin-Like Growth Factor-I and Insulin-Like Growth Factor Binding Protein-3 Serum Concentrations in Premenopausal Women with Obesity

DE PERGOLA, GIOVANNI, MAURO ZAMBONI, NICOLA PANNACCIULLI, EMANUELA TURCATO, FRANCESCO GIORGINO, FABIO ARMELLINI, FRANCESCO LOGOLUSO, MARCELLO SCIARAFFIA, OTTAVIO BOSELLO, RICCARDO GIORGINO. Divergent effects of short-term, very-low-calorie diet on insulinlike growth factor-I and insulin-like growth factor binding protein-3 serum concentrations in premenopausal women with obesity. Obes Res. 1998;6:408–415. Objective : Insulin-like growth factor-I (IGF-I) and insulinlike growth factor binding protein-3 (IGFBP-3) serum concentrations provide a good measure of the biological effects of growth, hormone. The aims of the present study were to: (1) investigate the associations of IGF-I and IGFBP-3 with body fat mass and distribution, and (2) evaluate the effects of 3 weeks of very-low-calorie diet (VLCD) (318 kcal/day, with 40 g protein, 35 g carbohydrate, and 2 g fat) on IGF-I and IGFBP-3 serum concentrations. Research Methods and Procedures : The study was performed in 21 nondiabetic premenopausal women with obesity (body mass index <27.0 kg/m²; age: ranging from 18 to 48 years). Body fat mass and distribution were measured by computed tomography. Results : Before dietary treatment, IGF-I and IGFBP-3 serum concentrations were inversely associated with visceral adipose tissue (VAT) area (p<0.005 and p<0.05, respectively), but not with either total body fat or subcutaneous adipose tissue area. VLCD produced a significant decrease of body mass index (p<0.001), total body fat (p<0.001), VAT (p<0.005), subcutaneous adipose tissue (p<0.001), IGF-I concentrations (p<0.05), and an increase of IGFBP-3 serum levels (p<0.001). The association of VAT with either IGF-I or IGFBP-3 serum concentrations was not maintained following VLCD. Discussion : Our study suggests that visceral adipose tissue, rather than adiposity per se, accounts for IGF-I and IGFBP-3 serum concentrations, and that rapid weight loss, possibly due to nutritional changes, results in lower IGF-I concentrations, higher IGFBP-3 concentrations, and abrogation of the inverse associations of VAT with IGF-I and IGFBP-3.     

Costs and benefits of breeding in human-altered landscapes for the Eagle Owl Bubo bubo

We studied a population of 23–25 Eagle Owl Bubo bubo pairs between 1994 and 2000 in a 1330-km² study plot in the central-eastern Italian Alps. Compared to random sites, territories were located at lower elevation and closer to intensively cultivated-urbanized valley floors. Early laying was associated with low elevation and negatively affected productivity. Diet was dominated by rats, hedgehogs and dormice ( n  = 978 prey items), all of them typical of low-elevation habitats. Higher productivity was associated with a higher proportion of rats in the diet of individual pairs. Low availability of rats resulted in a more diverse diet, in turn associated with low productivity. Territories were occupied every year in a non-random fashion, and those most occupied were characterized by higher productivity and higher occurrence of the favoured prey types in the diet, suggesting they were of superior quality. Eagle Owls also paid a cost associated with nesting near human-altered habitats: the main cause of mortality reported to local authorities was electrocution. This is an increasing cause of death for many European populations and may be a cause for conservation concern. Human persecution is also an important cause of mortality in some parts of the European range. Apart from such costs, the study population appeared to have adapted well to the proximity of humans: estimates of density and productivity were comparable to those recorded elsewhere in Europe. The pattern found in our population also held at higher spatial scales: data from 17 European populations showed density to be highest in low-elevation, human-altered landscapes.     

ROLE OF THE NITROGEN-FIXING BACTERIAL MICROFLORA IN THE EPIPHYTISM OF TILLANDSIA (BROMELIACEAE)

Nitrogen-fixing activity in the phyllosphere of 12 species of Tillandsia from different Mexican habitats was evaluated by the acetylene reduction assay, and nitrogen-fixing microorganisms were isolated and characterized. The leaves from eight of the 12 Tillandsia species examined exhibited nitrogenase activity in enrichment cultures. Among the microorganisms implicated—Agrobacterium, Bacillus, Erwinia, Pseudomonas, Rahnella, Vibrio, and Xanthomonas—only Bacillus megatherium reduced acetylene in pure culture. Our findings suggest that nitrogen fixation in the phyllosphere of the sampled epiphytes occurs under suitable conditions and that most of the bacteria involved are primarily soil and water inhabitants. The results also suggest a relationship between the composition of the nitrogen-fixing microbial communities grown on the leaf and the different development of the leaf area in Tillandsia due to the aerial components (wings) of the trichomes.     

Phytoplankton dynamics in a shallow,hypertrophic reservoir (Lake Arancio,Sicily)

Phytoplankton abundance and composition in the hypertrophic man-made Lake Arancio was analyzed, based on a programme of weekly sampling from May 1990 to November 1991 and supported by measurements of limnological parameters. The highest value of phytoplankton biomass (78 mg l^–1) was observed in October 1990, during a bloom of the desmid Closterium limneticum var. fallax, while the lowest (0.15 mg l^–1) was measured in April 1991. During spring, autumn and winter 1990, species of the genus Closterium dominated the community, in the sequence: C. aciculare, C. limneticum var. fallax, C. limneticum. The summer community was more diverse with the predominance of organisms belonging to Chlorophyceae (Chlamydomonas, Eudorina, Coelastrum) and Cyanophyceae (Microcystis, Anabaena). In spring 1991, there was a long clear-water phase during which small green algae (Ankyra, Oocystis) and cryptomonads dominated. Subsequently, the summer season was characterized by a clear sequence of dominants, drawn, in turns, from species belonging to: Bacillariophyceae, Dinophyceae, Cyanophyceae, Euglenophyceae. The physics of the reservoir and its depth, owing to filling/draining constraints in a summer-arid climate, appeared to play a key role in the dynamics of phytoplankton community.     

Immunological analysis of aconitase in pumpkin cotyledons: the absence of aconitase in glyoxysomes

Aconitase (EC 4.2.1.3) was purified by column chromatography and SDS-PAGE. Specific antibodies for aconitase were prepared after affinity purification of the antiserum with purified aconitase. The antibodies reacted with purified pumpkin aconitase, and with the 98 kDa protein band after electrophoretic fractionation of extracts of pumpkin cotyledons. Immunoblot analysis revealed a protein with similar molecular mass in extracts of several plants. The intensity of the 98 kDa band increased as pumpkin cotyledons developed in darkness, and decreased thereafter upon illumination. Aconitase activity showed a similar pattern. Anion exchange chromatography of a homogenate of pumpkin cotyledons, followed by western blotting, displayed the presence of immunoreactive protein bands only in fractions showing aconitase activity. The results indicate that the antibodies were specific for aconitase. When we investigated the presence of immunoreactive bands after sucrose gradient fractionation, aconitase was detected in the supernatant fractions and in mitochondria, while a very low amount was found in glyoxysomes. These data provide additional proof that aconitase is not localized in glyoxysomes.     

Homology of a 130-kb region enclosing the α-globin gene cluster,the α-locus controlling region,and two non-globin genes in human and mouse

The human -globin gene cluster (30 kb) is embedded in a GC-rich isochore very close to the telomere of Chromosome (Chr) 16p. The -Locus Controlling Region (-LCR) is located upstream of the adult -globin genes and has been shown to be essential for their expression. In this study we have been looking for expressed genes in the region upstream of the -globin cluster to understand the role of the LCR-like element in the expression and replication timing of flanking gene clusters. We show that the upstream -globin region is conserved over a 75-kb range and includes at least two oppositely transcribed non-globin genes, here referred to as Mid1 and Dist1. Complementary DNA sequences of 250 bp and 2.5 kb from Mid1 (coordinate-68) and Dist1 (coordinate-90 to-99), respectively, were isolated from human and mouse. The deduced partial amino acid sequences of these cDNAs are 81% and 95% identical for the Mid1 and Dist1 gene respectively. We have cloned a mouse cosmid contig which includes Dist1, Mid1, and the entire murine -globin cluster. The murine homolog of the -LCR was mapped upstream of the mouse globin genes at approximately the same position as in the human locus. Our results indicate that, in mouse and human, the -globin loci and their flanking sequences are homologous over a range of at least 130 kb. The structural homology of this region in both mammals suggests also a functional one and indicates the mouse as a potential model for studying the role of the -LCR controlling element in the regulation of expression and replication timing of the flanking gene clusters.The nucleotide sequence data reported in this paper have been submitted to GenBank and have been assigned the accession numbers M99623, M99624, M99625, and M99626.     

Discriminating physiological from non-physiological interfaces in structures of protein complexes: A community-wide study

Reliably scoring and ranking candidate models of protein complexes and assigning their oligomeric state from the structure of the crystal lattice represent outstanding challenges. A community-wide effort was launched to tackle these challenges. The latest resources on protein complexes and interfaces were exploited to derive a benchmark dataset consisting of 1677 homodimer protein crystal structures, including a balanced mix of physiological and non-physiological complexes. The non-physiological complexes in the benchmark were selected to bury a similar or larger interface area than their physiological counterparts, making it more difficult for scoring functions to differentiate between them. Next, 252 functions for scoring protein-protein interfaces previously developed by 13 groups were collected and evaluated for their ability to discriminate between physiological and non-physiological complexes. A simple consensus score generated using the best performing score of each of the 13 groups, and a cross-validated Random Forest (RF) classifier were created. Both approaches showed excellent performance, with an area under the Receiver Operating Characteristic (ROC) curve of 0.93 and 0.94, respectively, outperforming individual scores developed by different groups. Additionally, AlphaFold2 engines recalled the physiological dimers with significantly higher accuracy than the non-physiological set, lending support to the reliability of our benchmark dataset annotations. Optimizing the combined power of interface scoring functions and evaluating it on challenging benchmark datasets appears to be a promising strategy.     

Quinolinic acid but not MK-801 protects the dopaminergic system from 1-methyl-4- phenyl-1,2,3,6-tetrahydropyridine-induced toxicity in goldfish retina

The toxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, intravitreally injected in goldfish eye, involves interplexiform retinal neurons and depletes tyrosine hydroxylase immunoreactivity and dopamine levels. This induced neurotoxicity was prevented by the concomitant administration in nontoxic doses (10 μg) of quinolinic acid, an endogenous structural analogue of N-methyl -aspartate with excitotoxic properties. Quinolinic acid is ineffective on the retinal degeneration induced by 1-methyl-4- phenylpyridinium ion. This fact suggests that quinolinic acid inhibits the MAO-B oxidation of 1-methyl-4- phenyl-1,2,3,6-tetrahydropyridine. MK-801, a noncompetitive antagonist of glutamate NMDA-receptors, exerts partial protective effects on MPTP-induced delayed toxicity in mammals. In the goldfish eye, MK-801, injected in low concentration, and in conjunction with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine or 1-methyl-4-phenylpyridinium ion, did not prevent retinal neurodegeneration. Ten μg of MK-801 alone did not affect retinal neurons, while a higher concentration (20 μg) causes the chromatolysis of some photoreceptor nuclei.     

Molecular dynamics studies on mutants of Cu,Zn superoxide dismutase: The functional role of charged residues in the electrostatic loop VII

Molecular dynamics (MD) calculations have been performed on mutants of superoxide dismutase (SOD) on some residues present in the electrostatic loop. These calculations have provided the solution structures for the mutants Thr-137 → IIe and Arg; Lys-136 → Ala; Glu-132 → Gln; Glu-133 → Gln; Glu-132, Glu-133 → Gln-132, Gln-133 and → Gln-132, Lys-133. The structural and dynamic properties of these mutants have been correlated with the catalytic properties and available spectroscopic data. The water molecule present in the active site close to the copper ion in wild type (WT) SOD is missing in the MD average structure of the Thr-137 → IIe mutant, while this molecule is present in the MD average structures of all the other mutants and of WT SOD. This agrees with the experimental data. This is an important result that shows the validity of our calculations and their ability to reproduce even subtle structural features. Addition of one or more positive charges on the 132 and/or 133 positions does not sizably perturb the structure of the active site channel, while the introduction of a positively charged residue (Arg) on position 137 has a large effect on the structure of the electrostatic loop. Analysis of the MD average structures of these mutants has pointed out that the simple electrostatic effects of charged residues in the channel are not the only factor relevant for enzymatic behavior but that the structure of the electrostatic loop and the location of the charged residues also contribute to the catalytic properties of SOD. © 1994 John Wiley & Sons, Inc.     

Steroidogenic capacity and oxidative stress-related parameters in human luteal cell regression

The steroidogenic capacity and oxidative stress-related parameters of the human corpus luteum (CL) at different stages of the luteal phase were studied under basal and human chorionic gonadotropin (hCG)-stimulated conditions. Mid CL exhibited the maximal steroidogenic capacity, together with lower levels of glutathione and higher thiobarbituric acid reactants content, macrophage count, and superoxide dismutase (SOD) activity, compared to the late CL. Addition of hCG to luteal cell cultures led to a preferential increase in progesterone synthesis in the late CL compared to the mid CL, without changes in the oxidative stress-related parameters, except for the increased SOD activity found in the late CL. It is concluded that an oxidative stress condition is established in the mid CL, coinciding with the maximal steroidogenic capacity and macrophage infiltration of the organ, which be of relevance as one of the major mechanisms initiating CL involution in the human.