PubMed Health⌕ Search

Biomedical subjects

Maria Romano

Publications and source records attributed to Maria Romano.

14 recordsLinked to original sources
PubMed2007

Consequences of prenatal androgen exposure for the reproductive performance of female pheasants (Phasianus colchicus).

Maternal hormones in vertebrate eggs can mediate important forms of maternal effects. However, the function of hormone transfer to the eggs is still debated, especially because long-term fitness consequences have been little studied. We investigated the effect of prenatal exposure to physiologically elevated yolk testosterone (T) levels on reproduction of female pheasants (Phasianus colchicus) in captivity. We found that females hatching from T-injected eggs (T-females) had a lower egg-laying rate than controls, and their eggs were more frequently infertile than those laid by control females. There were no effects of prenatal maternal treatment on egg size and yolk T concentration, but eggs carrying a female embryo laid by T-females had smaller yolks than eggs with a male embryo, while there was no sex difference in yolk size among the eggs laid by control females. Progeny sex ratio was unaffected by maternal treatment. These findings suggest that the transfer of high androgen levels to the eggs by the mother is constrained by complex trade-offs between direct effects on her daughters' reproduction and by trans-generational differential consequences on male and female descendants.

Animals↗
PubMed2006

Inorganic phosphate inhibits growth of human osteosarcoma U2OS cells via adenylate cyclase/cAMP pathway.

In order to elucidate how phosphate regulates cellular functions, we investigated the effects of inorganic phosphate (Pi) on adenylate cyclase (AC)/cyclic AMP (cAMP) axis. Here we describe that Pi treatment of human osteosarcoma U2OS cells results in a decrease of both intracellular cAMP levels and AC activity, and in a cell growth inhibition. The phosphate-triggered effects observed in U2OS cells are not a widespread phenomenon regarding all cell lines, since other cell lines screened respond differently to parallel Pi treatments. In U2OS cell line, the AC activity/cAMP downregulation is accompanied by significant variations in the levels of some membrane proteins belonging to the AC system. Remarkably, the above effects are blunted by pharmacological inhibition of sodium-dependent phosphate transport. Moreover, 8-Br-cAMP and other cAMP-elevating agents, such as IBMX and forskolin, interestingly, prevent the cell growth inhibition in response to phosphate. Our results enforce the increasing evidences of phosphate as a signaling molecule, identifying in U2OS cell line the AC/cAMP axis, as a novel-signaling pathway modulated by phosphate to ultimately affect cell growth.

Adenylyl Cyclases↗
PubMed2006

Effects of elevated yolk androgens on perinatal begging behavior in yellow-legged gull (Larus michahellis) chicks.

Maternal hormones may represent an important pathway by which mothers can adaptively adjust offspring traits and performance to suit the prevailing environmental conditions. Earlier studies of birds have shown that egg androgens of maternal origin may enhance post-natal offspring 'begging' displays, functioning to solicit parental care. Here we investigate the effects of elevated egg androgen levels on the prenatal begging behavior of yellow-legged gull (Larus michahellis) chicks. At laying, we experimentally increased the concentration of yolk testosterone (T) within the natural range of variation, and, shortly before hatching, we compared the structural properties, rate, and loudness of vocalizations of embryos developing in T- and oil-injected (control) eggs. In addition, we compared the early post-hatch begging rate (measured as the pecking rate towards a dummy gull head) in chicks of the two experimental groups. We found that T embryos produced louder embryonic vocalizations than controls, whereas structural properties and the calling rate did not differ between T and control embryos. The post-hatch begging rate was unaffected by T treatment, but strongly decreased with increasing chick body mass, suggesting that intensity of the begging display was sensitive to chick state and may therefore reliably indicate the need of food in this species. Therefore, the results of this study show for the first time that prenatal T exposure modulates the quality of embryonic vocalizations, but are not in accordance with previous findings reporting increased post-hatching begging intensity following increased prenatal exposure to androgens.

Animals↗
PubMed2006

The (ADP-ribosyl)ation reaction in thermophilic bacteria.

Species of Alicyclobacillus, Bacillus and Thermus genera were selected in order to study the possible presence of the (ADP-ribosyl)ation system. These bacteria are thermophilic, aerobic, and were isolated from different geothermal sources. Both activity and expression of (ADP-ribosyl)ating proteins were tested in cells at different growth phases, and evidence of an active system was obtained in all analyzed microorganisms, with comparable enzymatic levels. Immunochemical analyses with polyclonal antibodies against both eukaryotic anti-(ADP-ribose) transferase and anti-poly(ADP-ribose) polymerase revealed, for all tested organisms, an immunosignal localized in the range of molecular masses between 43-53 kD. Several proteins of various molecular masses were found as ADP-ribose acceptors. Reaction product analyses showed mono(ADP-ribose) to be the only synthesized compound.

ADP Ribose Transferases↗
PubMed2005

Stressed mothers lay eggs with high corticosterone levels which produce low-quality offspring.

Organisms frequently encounter stressful ecological conditions. In vertebrates, a major mechanism of physiological response to stress is mediated by the hypothalamic-pituitary-adrenal axis and results in increased secretion of glucocorticosteroids, which can have adverse consequences on diverse phenotypic traits affecting fitness. Maternal stress may thus have carry-over effects on progeny if it influences pre-natal offspring environment in terms of glucocorticosteroid concentration, although this hypothesis has never been tested in any species under field conditions. We manipulated stress experienced by female barn swallows Hirundo rustica, by exposing them to a predator during laying and measured egg corticosterone concentration. Stressed females laid eggs with greater corticosterone concentration than controls exposed to a herbivore. In another experiment, we injected physiological doses of corticosterone in the egg albumen and compared the phenotype of offspring originating from these eggs with their control siblings originating from either sham-inoculated or unmanipulated eggs and reared in the same nest. Eggs injected with corticosterone had lower hatchability and produced fledglings with smaller body size and slower plumage development than did control eggs. Nestling body size in our study population predicts long-term survival. Thus, maternal stress impaired offspring phenotype and viability by increasing transmission of glucocorticosteroids to the eggs. This study identifies a novel mechanism mediating early maternal effects whereby maternal stress affects offspring quality. These results are relevant to biological conservation because they disclose a mechanism that can link environmental conditions to population productivity and viability.

Analysis of Variance↗
PubMed2005

Antepartum cardiotocography: a study of fetal reactivity in frequency domain.

Cardiotocography (CTG) is the most widely used diagnostic technique in clinical practice to monitor fetal health. Cardiotocographic recording also permits to assess maturation of the fetal autonomous nervous system (ANS): fetal heart rate (FHR) modifications may reveal ANS' reactions to stimuli. To assess fetal reactivity, physicians evaluate specific clinical CTG parameters, generally, by means of visual inspection, thus depending on observer's expertise, with lack of reproducibility. Still nowadays, there is a very high intra- and inter-observer variation in the assessment of FHR patterns. More objective methods for CTG interpretation are of crucial importance. For adults, frequency analysis of heart rate variability (HRV) is a non-invasive and powerful method to investigate ANS activity. This frequency analysis can also be a valid support for a better knowledge of fetal ANS functional state and reactions. Indeed, fetal HRV is a good indicator of fetal well-being in non-stress conditions. Fetal reactivity is a very important CTG characteristic used to diagnose fetal distress, but its interpretation is still uncertain. The aim of this study is to characterise fetal reactivity proposing new fetal HRV frequency parameters to support a more exhaustive CTG analysis.

Cardiotocography↗
PubMed2005

Examination marks of male university students positively correlate with finger length ratios (2D:4D).

Intersexual and intrasexual variation in second to fourth digit length (2D:4D) in humans may result from differential exposure to fetal testosterone. 2D:4D predicts several physiological, psychological and performance traits in adulthood. These relationships may reflect the 'pleiotropic' effects of testosterone on development of digits and diverse organ systems, which are expressed in adulthood. We hypothesized that 2D:4D also predicts academic success of students. 2D:4D of right hand positively predicted examination marks of males from two three-year degree courses (TYDCs). Marks of females did not covary with 2D:4D. Males from the two TYDCs differed in 2D:4D. The present results thus add to the rapidly accumulating literature on 2D:4D showing correlations with phenotypic traits in humans. If testosterone affects 2D:4D and intellectual performance, our results suggest that testosterone levels are under stabilizing selection because of effects on performance traits documented in previous studies and antagonistic effects on intellectual performance (present study).

Achievement↗
PubMed2005

Effects of elevated egg corticosterone levels on behavior, growth, and immunity of yellow-legged gull (Larus michahellis) chicks.

Eggs of vertebrates contain steroid hormones of maternal origin that may influence offspring performance. Recently, it has been shown that glucocorticoids, which are the main hormones mediating the stress response in vertebrates, are transmitted from the mother to the egg in birds. In addition, mothers with experimentally elevated corticosterone levels lay eggs with larger concentrations of the hormone, which produce slow growing offspring with high activity of the hypothalamo-adrenal axis under acute stress. However, the effects and function of transfer of maternal corticosterone to the eggs are largely unknown. In the present study, we injected corticosterone in freshly laid eggs of yellow-legged gulls (Larus michahellis), thus increasing the concentration of the hormone within its natural range of variation, and analyzed the effect of manipulation on behavioral, morphological, and immune traits of the offspring in the wild. Eggs injected with corticosterone had similar hatching success to controls, but hatched later. Mass loss during incubation was greater for corticosterone-treated eggs, except for the last laid ones. Corticosterone injection reduced rate and loudness of late embryonic vocalizations and the intensity of chick begging display. Tonic immobility response, reflecting innate fearfulness, was unaffected by hormone treatment. Elevated egg corticosterone concentrations depressed T-cell-mediated immunity but had no detectable effects on humoral immune response to a novel antigen, viability at day 10, or growth. Present results suggest that egg corticosterone can affect the behavior and immunity of offspring in birds and disclose a mechanism mediating early maternal effects whereby stress experienced by females may negatively translate to offspring phenotypic quality.

Animals↗
PubMed2005

Experimental manipulation of yolk testosterone affects digit length ratios in the ring-necked pheasant (Phasianus colchicus).

In humans, most of the mammals and one bird species studied so far, the relative length of individual digits is sexually dimorphic. Most studies of humans have been concerned with the ratio between second (2D) and fourth digits (4D), whereas some studies of humans and other mammals have also investigated other digit ratios. Inter- and intra-sexual variation in 2D:4D may depend on differential exposure to androgens during embryonic life, and the genetic mechanisms linking 2D:4D to androgens may be mediated by Hox genes. Because Hox genes are conserved in vertebrates, similar patterns of variation in digit ratios might be expected across vertebrate classes. The observation of correlations between digit ratios and physiological, psychological and performance traits in humans has generated interest in exploring the possibility that digit ratios are a marker of embryonic exposure to androgens, which have diverse consequences on several phenotypic traits. However, the hypothesis that digit ratios depend on androgen effects during development has never been tested experimentally. In this study, we increased testosterone concentration in ring-necked pheasant eggs and measured length ratios between the second, third and fourth digits of both feet in fully grown offspring. Females from testosterone-injected eggs had larger 2D:3D in the left foot, whereas this was not the case in males. The other digit ratios were unaffected by hormone treatment in both sexes. However, digit ratios showed no sexual dimorphism among controls. Thus, present results are consistent with the hypothesis that variation in testosterone levels during development affects digit ratios.

Animals↗
PubMed2004

Ecological conditions during winter affect sexual selection and breeding in a migratory bird.

Populations of migratory birds have undergone marked declines, although the causes and mechanisms remain unknown. Because environmental effects on population dynamics are mediated by the effects of ecological factors on individuals, understanding changes in individual phenotypes in response to ecological conditions is key to understanding population trends. We show that breeding individuals of a declining population of trans-Saharan migratory barn swallows, Hirundo rustica, were affected by environmental conditions, as estimated from the normalized difference vegetation index (NDVI), reflecting primary production, in their winter quarters. The breeding dates of the same individuals in consecutive breeding seasons were advanced and clutch sizes were larger after winters with high NDVI in the winter quarters. Feather moult was also affected by winter conditions, with consequences for male sexual attractiveness. Length of tail ornament was positively correlated with NDVI during the previous winter, and males with large tail ornaments reproduced earlier and had larger clutches. The mean annual breeding date of the population was earlier and breeding success was increased after favourable winters, but this result was mainly determined by a single winter with very low NDVI. Thus, ecological conditions in Africa influence individual performance and productivity in a barn swallow population.

Africa South of the Sahara↗
PubMed2004

Adenylate cyclase regulation via proteasome-mediated modulation of Galphas levels.

The adenylate cyclase (AC)/cyclic AMP (cAMP)/cAMP-dependent protein kinase pathway controls many biological phenomena. The ubiquitin/proteasome system, controlling the levels of many proteins, modulates important cellular processes such as cell cycle and cell growth. Here we describe a novel mechanism for AC regulation by proteasome pathway. Pharmacological inhibition of proteasome function in human osteosarcoma U2OS cells results in up-regulation of AC activity, increase of levels of alpha subunit of heterotrimeric stimulatory GTP-binding proteins (alphas) and, remarkably, also in preventing of beta-adrenergic receptor-mediated down-regulation of alphas protein levels. Accumulation of alphas protein is also accompanied by the appearance of polyubiquitinated alphas species. Our results: (1) identify alphas protein as a novel proteasome substrate in mammalian cells; (2) indicate that proteasome might play a physiological role in controlling AC/cAMP mediated pathways by modulating the levels of Galphas protein; (3) suggest a role for the proteasome also in controlling alphas-mediated signaling pathways other than those affecting AC complex.

Adenylyl Cyclases↗
PubMed2003

Experimental manipulation of egg carotenoids affects immunity of barn swallow nestlings.

The yolk of bird eggs contains maternal carotenoids that may act as antioxidants thus influencing offspring performance and survival. However, to our knowledge, this hypothesis has not been subjected to experimental tests and the function of transmission of carotenoids to the egg is largely unknown. We directly manipulated the concentration of the main carotenoid (lutein) in the eggs of barn swallows (Hirundo rustica) and analysed the effect of experimental manipulation on growth of nestlings and two fundamental components of their acquired immunity. Nestlings hatched from lutein-inoculated eggs had larger T-cell-mediated immune response compared with those of two control groups. T-cell-mediated immune response predicted nestling survival until fledging. However, lutein inoculation did not affect antibody response to an immunogen, body mass, tarsus length or plumage development. Nestling body mass and plumage development declined with egg laying order, but the effects of lutein inoculation were independent of egg laying order for all traits. Our results show that maternal yolk carotenoids can have a major effect in promoting a fundamental component of immunity that predicts offspring survival and suggests that adaptive early maternal effects can be mediated by transmission of antioxidants to eggs.

Animals↗
PubMed2002

Early maternal effects mediated by immunity depend on sexual ornamentation of the male partner.

Vertebrates have an immature immune system soon after birth, and parasites can therefore be particularly virulent to young hosts. Transfer of immune factors via the egg can give rise to early maternal effects with important consequences for offspring fitness, as maternally derived immunity confers anti-parasite protection. Mothers are expected to allocate immunity differentially to the eggs according to the reproductive value of their offspring as influenced by the quality of their father. In this study, we analysed transmission to the yolk of antibodies specific to an antigen (Newcastle disease virus vaccine, NDV) by vaccinated female barn swallows (Hirundo rustica) mated to males whose secondary sexual characteristics had been manipulated. Concentration of anti-NDV antibodies in the yolk positively covaried with that in maternal plasma. Anti-NDV antibodies were more concentrated in the first but not the fourth eggs laid by females mated with tail-elongated males compared with those mated with tail-shortened and control males. This experiment shows that allocation of maternal immune factors to the eggs is affected by quality of the male, as signalled by its secondary sexual characteristic. Thus, early maternal effects are influenced by sexual attractiveness of male mates and are mediated by immunity.

Animals↗