FABIO NAPOLITANO 1963- 2022

Editoria

Common dynamical features of sensory adaptation in photoreceptors and olfactory sensory neurons

Sensory systems adapt, i.e., they adjust their sensitivity to external stimuli according to the ambient level. In this paper we show that single cell electrophysiological responses of vertebrate olfactory receptors and of photoreceptors to different input protocols exhibit several common features related to adaptation, and that these features can be used to investigate the dynamical structure of the feedback regulation responsible for the adaptation. In particular, we point out that two different forms of adaptation can be observed, in response to steps and to pairs of pulses. These two forms of adaptation appear to be in a dynamical trade-off: the more adaptation to a step is close to perfect, the slower is the recovery in adaptation to pulse pairs and viceversa. Neither of the two forms is explained by the dynamical models currently used to describe adaptation, such as the integral feedback model

Effect of pre-partum habituation to milking routine on behaviour and lactation performance of buffalo heifers

The aim of this study was to investigate the effect pre-partum habituation in the milkingparlour on behaviour and lactation performance of buffalo heifers. Sixteen buffalo heifersin late gestation were used for this study. The animals, with an age ranging from 30 to44 months at the start of the study, were equally allocated into two treatments and bal-anced for estimated calving date. Eight animals received pre-partum habituation for 10 daysbefore the estimated calving date (group H), while the eight others received no treatmentand served as the control (group C). During the pre-partum habituation sessions, group Hanimals were moved to the milking parlour and left for 10 min in the milking stall onceeach day, where the udder was thoroughly washed with warm water, wiped with a dis-posable towel and massaged. The behaviours, registered from entrance into the milkingstall to exit, were step and kick. After calving milk flow profiles, milk yield and milk qual-ity variables were determined along with behavioural recordings. The H animals duringthe habituation procedure showed a reduction in the number of steps (P < 0.001) and kicks(P < 0.01). After calving the H animals performed fewer steps than the control animals at 0(P < 0.001), 3 (P < 0.01), 6 (P < 0.01), 13 (P < 0.01) and 20 (P < 0.01) days after calving. Animalsfrom group H also performed fewer kicks than control animals at 0 (P < 0.001), 3 (P < 0.01),6 (P < 0.01) and 13 (P < 0.01) days after calving. In the C group a reduction in the numberof steps (P < 0.001) and kicks (P < 0.001) was observed as lactation proceeded, whereas forgroup H only a tendency for a reduction over lactation was detected. Pre-partum habitu-ation did not significantly affect milk quality or milk flow variables. Milk yield in the first3 min of milking (P < 0.001), and average milk flow (P < 0.001), increased throughout theexperimental period, whereas the duration of the pre-milking phase decreased as lactationproceeded (P < 0.001). This study shows that buffalo heifers exposed to a pre-partum habit-uation programme performed fewer steps and kicks than control animals during milking.Therefore, it is concluded that using this treatment can reduce the level of restlessness inbuffalo heifers during milking

Dry-aged beef steaks: effect of dietary supplementation with Pinus taeda hydrolyzed lignin on sensory profile, colorimetric and oxidative stability

Flavor is one of the main factors involved in consumer meat-purchasing decision and use of natural antioxidants in animal feeding had a great appeal for consumers. The aim of this trial is to evaluate the effect of Pinus taeda hydrolyzed lignin (PTHL) feed addition on oxidative stability, volatile compounds characteristics, and sensory attributes of 35 days dry-aged beef steaks. Forty steer six months old were randomly divided into a control group (CON; n = 20) and an experimental group (PTHL; n = 20). Both groups were fed ad libitum for 120 days with the same TMR and only the PTHL group received PTHL supplement. Samples of LT muscle were removed from carcasses and dry aged for 35 days at 2 °C, 82% of humidity, and 0.4 m/s of ventilation and then analyzed. Meat of CON group showed lower yellowness (p < 0.01) and higher TBARS (p < 0.01) values. Moreover, CON meat showed higher volatile aldehydes and lower sulfur compounds (p < 0.01), with higher unpleasant odor (p < 0.05) and meaty odor (p < 0.01) score revealed by sensory assessors. PTHL inclusion in beef diet delayed the oxidative mechanisms in 35 days dry-aged steaks, resulting in an improved colorimetric, volatolomic, and sensory profile

A rate-distortion theory for gene regulatory networks and its application to logic gate consistency

ABSTRACT Motivation: A gene regulatory network in which the modes (activation/ inhibition) of the transcriptional regulations are known and in which gene expression assumes boolean values can be treated as a system of linear equations over a binary field, i.e. as a constraint satisfaction problem for an information code. Results: For currently available gene networks, we show in this article that the distortion associated with the corresponding information code is much lower than expected from null models, and that it is close to (when not lower than) the Shannon bound determined by the ratedistortion theorem. This corresponds to saying that the distribution of regulatory modes is highly atypical in the networks, and that this atypicality greatly helps in avoiding contradictory transcriptional actions. Choosing a boolean formalism to represent the gene networks, we also show how to formulate criteria for the selection of gates that maximize the compatibility with the empirical information available on the transcriptional regulatory modes. Proceeding in this way, we obtain in particular that non-canalizing gates are upper-bounded by the distortion, and hence that the boolean gene networks are more canalizing than expected from null models

Plasma Retinol and Prognosis of Postmenopausal Breast Cancer Patients

Abstract Background: The role of retinol (vitamin A) in breast cancer prognosis has never been investigated in postmenopausal women. We prospectively assessed the long-term prognostic role of retinol plasma levels in a cohort of postmenopausal breast cancer patients. Patients and Methods: We investigated 208 women self-reported as postmenopausal operated on for T1-2N0M0 breast cancer who participated in a chemoprevention trial as controls and never received chemotherapy or hormone therapy. Plasma samples were collected 3 months (median) after surgery and assayed within 3 weeks for retinol. Minimum and median potential follow-up were 12 and 15 years, respectively. The main analyses were on all women and on a subgroup ages ≥55 years, assumed too old to be in perimenopause. The main end point was breast cancer death. Breast cancer survival was estimated by the Kaplan-Meier method. The hazard ratios of breast cancer death by retinol level were estimated by Cox models stratified for age, where relevant, and recruitment period, and adjusted for tumor size and histology. Results: At 12 years, patients with low retinol (&lt;2.08 μmol/L, median of distribution) had lower breast cancer survival than those with high retinol (log-rank P = 0.052); the difference was significant for women ≥55 years (log-rank P = 0.006). The adjusted hazard ratios for low versus high retinol were 2.11 (95% confidence interval, 1.08-4.14) for all women and 3.58 (95% confidence interval, 1.50-8.57) for those ≥55 years. Conclusions: Low plasma retinol strongly predicts poorer prognosis in postmenopausal breast cancer patients. Retinol levels should be determined as part of the prognostic workup. (Cancer Epidemiol Biomarkers Prev 2009;18(1):42–8

Sourdough fermented breads are more digestible than those started with baker’s yeast alone. An in vivo challenge dissecting distinct gastrointestinal responses

As a staple food, bread digestibility deserves a marked nutritional interest. Combining wide-spectrum characterization of breads, in vitro nutritional indices, and in vivo postprandial markers of gastrointestinal function, we aimed at comparing the digestibility of sourdough and baker’s yeast breads. Microbiological and biochemical data showed the representativeness of the baker´s yeast bread (BYB) and the two sourdough breads (SB and t-SB, mainly differing for the time of fermentation) manufactured at semi-industrial level. All in vitro nutritional indices had the highest scores for sourdough breads. Thirty-six healthy volunteers underwent an in vivo challenge in response to bread ingestion, while monitoring gallbladder, stomach, and oro-cecal motility. SB, made with moderate sourdough acidification, stimulated more appetite and induced lower satiety. t-SB, having the most intense acidic taste, induced the highest fullness perception in the shortest time. Gallbladder response did not differ among breads, while gastric emptying was faster with sourdough breads. Oro-cecal transit was prolonged for BYB and faster for sourdough breads, especially when made with traditional and long-time fermentation (t-SB), whose transit lasted ca. 20 min less than BYB. Differences in carbohydrate digestibility and absorption determined different post-prandial glycaemia responses. Sourdough breads had the lowest values. After ingesting sourdough breads, which had a concentration of total free amino acids markedly higher than that of BYB, the levels in blood plasma were maintained at constantly high levels for extended time

Liver Steatosis, Gut-Liver Axis, Microbiome and Environmental Factors. A Never-Ending Bidirectional Cross-Talk

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and parallels comorbidities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. Recent studies describe the presence of NAFLD in non-obese individuals, with mechanisms partially independent from excessive caloric intake. Increasing evidences, in particular, point towards a close interaction between dietary and environmental factors (including food contaminants), gut, blood flow, and liver metabolism, with pathways involving intestinal permeability, the composition of gut microbiota, bacterial products, immunity, local, and systemic inflammation. These factors play a critical role in the maintenance of intestinal, liver, and metabolic homeostasis. An anomalous or imbalanced gut microbial composition may favor an increased intestinal permeability, predisposing to portal translocation of microorganisms, microbial products, and cell wall components. These components form microbial-associated molecular patterns (MAMPs) or pathogen-associated molecular patterns (PAMPs), with potentials to interact in the intestine lamina propria enriched in immune cells, and in the liver at the level of the immune cells, i.e., Kupffer cells and stellate cells. The resulting inflammatory environment ultimately leads to liver fibrosis with potentials to progression towards necrotic and fibrotic changes, cirrhosis. and hepatocellular carcinoma. By contrast, measures able to modulate the composition of gut microbiota and to preserve gut vascular barrier might prevent or reverse NAFL

ATP Sensitive Potassium Channels in the Skeletal Muscle Function: Involvement of the KCNJ11(Kir6.2) Gene in the Determination of Mechanical Warner Bratzer Shear Force

The ATP-sensitive K-channels (KATP) are distributed in the tissues coupling metabolism with K ions efflux. KATP subunits are encoded by KCNJ8 (Kir6.1), KCNJ11 (Kir6.2), ABCC8 (SUR1), and ABCC9 (SUR2) genes, alternative RNA splicing give rise to SUR variants that confer distinct physiological properties on the channel. An high expression/activity of the sarco-KATP channel is observed in various rat fast-twitch muscles, characterized by elevated muscle strength, while a low expression/activity is observed in the slow twitch muscles characterized by reduced strength and frailty. Down-regulation of the KATP subunits of fast-twitch fibers is found in conditions characterized by weakness and frailty. KCNJ11 gene knockout mice have reduced glycogen, lean phenotype, lower body fat, and weakness. KATP channel is also a sensor of muscle atrophy. The KCNJ11 gene is located on BTA15, close to a QTL for meat tenderness, it has also a role in glycogen storage, a key mechanism of the postmortem transformation of muscle into meat. The role of KCNJ11 gene in muscle function may underlie an effect of KCNJ11 genotypes on meat tenderness, as recently reported. The fiber phenotype and genotype are important in livestock production science. Quantitative traits including meat production and quality are influenced both by environment and genes. Molecular markers can play an important role in the genetic improvement of animals through breeding strategies. Many factors influence the muscle Warner-Bratzler shear force including breed, age, feeding, the biochemical, and functional parameters. The role of KCNJ11gene and related genes on muscle tenderness will be discussed in the present review

Dynamic correlations in symmetric electron-electron and electron-hole bilayers

The ground-state behavior of the symmetric electron-electron and electron-hole bilayers is studied by including dynamic correlation effects within the quantum version of Singwi, Tosi, Land, and Sjolander (qSTLS) theory. The static pair-correlation functions, the local-field correction factors, and the ground-state energy are calculated over a wide range of carrier density and layer spacing. The possibility of a phase transition into a density-modulated ground state is also investigated. Results for both the electron-electron and electron-hole bilayers are compared with those of recent diffusion Monte Carlo (DMC) simulation studies. We find that the qSTLS results differ markedly from those of the conventional STLS approach and compare in the overall more favorably with the DMC predictions. An important result is that the qSTLS theory signals a phase transition from the liquid to the coupled Wigner crystal ground state, in both the electron-electron and electron-hole bilayers, below a critical density and in the close proximity of layers (d <~ r_sa_0^*), in qualitative agreement with the findings of the DMC simulations.Comment: 13 pages, 11 figures, 2 table