SLC15 family of peptide transporters in GtoPdb v.2021.3

The Solute Carrier 15 (SLC15) family of peptide transporters, alias H+-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their key role in the cellular uptake of di- and tripeptides (di/tripeptides). Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from overall dietary protein digestion, SLC15A2 (PEPT2) mainly allows renal tubular reuptake of di/tripeptides from ultrafiltration and brain-to-blood efflux of di/tripeptides in the choroid plexus, SLC15A3 (PHT2) and SLC15A4 (PHT1) interact with both di/tripeptides and histidine, e.g. in certain immune cells, and SLC15A5 has unknown physiological function. In addition, the SLC15 family of peptide transporters variably interacts with a very large number of peptidomimetics and peptide-like drugs. It is conceivable, based on the currently acknowledged structural and functional differences, to divide the SLC15 family of peptide transporters into two subfamilies [3]

SLC15 family of peptide transporters in GtoPdb v.2023.1

The Solute Carrier 15 (SLC15) family of peptide transporters, alias H+-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their key role in the cellular uptake of di- and tripeptides (di/tripeptides). Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from overall dietary protein digestion, SLC15A2 (PEPT2) mainly allows renal tubular reuptake of di/tripeptides from ultrafiltration and brain-to-blood efflux of di/tripeptides in the choroid plexus, SLC15A3 (PHT2) and SLC15A4 (PHT1) interact with both di/tripeptides and histidine, e.g. in certain immune cells, and SLC15A5 has unknown physiological function. In addition, the SLC15 family of peptide transporters variably interacts with a very large number of peptidomimetics and peptide-like drugs. It is conceivable, based on the currently acknowledged structural and functional differences, to divide the SLC15 family of peptide transporters into two subfamilies [3]

the colon epithelium as a target for the intracellular antioxidant activity of hydroxytyrosol a study on rat colon explants

Abstract The study aimed at investigating the intracellular antioxidant activity of hydroxytyrosol (HT), one of the most potent natural antioxidant phenolic compounds, directly on the colon epithelium, under basal physiological and pro-oxidant conditions. In situ confocal microscopy on rat colon explants loaded with the ROS sensitive fluorescent probe CM-H2DCFDA was applied. HT exerted a dose-dependent decrease of the basal ROS production of superficial colonocytes. Also, it induced a dose-dependent antioxidant action on the colon mucosa exposed to an H2O2 challenge. The effect of 100 µM HT was comparable to that of 10 µM Trolox. The HT effect was also tested against tert-butyl peroxide, another pro-oxidant. The results showed that HT can directly contribute to the redox balance of colonic epithelium by reducing ROS in both basal and pro-oxidant conditions, and support the potential of HT as a functional food ingredient with applications in protecting the intestinal mucosa against oxidative stress

SLC15 family of peptide transporters (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

The Solute Carrier 15 (SLC15) family of peptide transporters, alias H+-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their key role in the cellular uptake of di- and tripeptides (di/tripeptides). Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from overall dietary protein digestion, SLC15A2 (PEPT2) mainly allows renal tubular reuptake of di/tripeptides from ultrafiltration and brain-to-blood efflux of di/tripeptides in the choroid plexus, SLC15A3 (PHT2) and SLC15A4 (PHT1) interact with both di/tripeptides and histidine, e.g. in certain immune cells, and SLC15A5 has unknown physiological function. In addition, the SLC15 family of peptide transporters variably interacts with a very large number of peptidomimetics and peptide-like drugs. It is conceivable, based on the currently acknowledged structural and functional differences, to divide the SLC15 family of peptide transporters into two subfamilies

Effects of Short-Term Fasting on mRNA Expression of Ghrelin and the Peptide Transporters PepT1 and 2 in Atlantic Salmon (Salmo salar)

Food intake is a vital process that supplies necessary energy and essential nutrients to the body. Information regarding luminal composition in the gastrointestinal tract (GIT) collected through mechanical and nutrient sensing mechanisms are generally conveyed, in both mammals and fish, to the hypothalamic neurocircuits. In this context, ghrelin, the only known hormone with an orexigenic action, and the intestinal peptide transporters 1 and 2, involved in absorption of dietary di- and tripeptides, exert important and also integrated roles for the nutrient uptake. Together, both are potentially involved in signaling pathways that control food intake originating from different segments of the GIT. However, little is known about the role of different paralogs and their response to fasting. Therefore, after 3 weeks of acclimatization, 12 Atlantic salmon (Salmo salar) post-smolt were fasted for 4 days to explore the gastrointestinal response in comparison with fed control (n = 12). The analysis covered morphometric (weight, length, condition factor, and wet content/weight fish %), molecular (gene expression variations), and correlation analyses. Such short-term fasting is a common and recommended practice used prior to any handling in commercial culture of the species. There were no statistical differences in length and weight but a significant lower condition factor in the fasted group. Transcriptional analysis along the gastrointestinal segments revealed a tendency of downregulation for both paralogous genes slc15a1a and slc15a1b and with significant lowered levels in the pyloric ceca for slc15a1a and in the pyloric ceca and midgut for slc15a1b. No differences were found for slc15a2a and slc15a2b (except a higher expression of the fasted group in the anterior midgut), supporting different roles for slc15 paralogs. This represents the first report on the effects of fasting on slc15a2 expressed in GIT in teleosts. Transcriptional analysis of ghrelin splicing variants (ghrl-1 and ghrl-2) showed no difference between treatments. However, correlation analysis showed that the mRNA expression for all genes (restricted to segment with the highest levels) were affected by the residual luminal content. Overall, the results show minimal effects of 4 days of induced fasting in Atlantic salmon, suggesting that more time is needed to initiate a large GIT response

Streaming Algorithm for Euler Characteristic Curves of Multidimensional Images

We present an efficient algorithm to compute Euler characteristic curves of gray scale images of arbitrary dimension. In various applications the Euler characteristic curve is used as a descriptor of an image. Our algorithm is the first streaming algorithm for Euler characteristic curves. The usage of streaming removes the necessity to store the entire image in RAM. Experiments show that our implementation handles terabyte scale images on commodity hardware. Due to lock-free parallelism, it scales well with the number of processor cores. Our software---CHUNKYEuler---is available as open source on Bitbucket. Additionally, we put the concept of the Euler characteristic curve in the wider context of computational topology. In particular, we explain the connection with persistence diagrams

Downscaling With an Unstructured Coastal-Ocean Model to the Goro Lagoon and the Po River Delta Branches

The Goro Lagoon Finite Element Model (GOLFEM) presented in this paper concentrates on the high-resolution downscaled model of the Goro Lagoon, along with five Po river branches and the coastal area of the Po delta in the northern Adriatic Sea (Italy) where crucial socio-economic activities take place. GOLFEM was validated by means of validation scores (bias – BIAS, root mean square error – RMSE, and mean absolute error – MAE) for the water level, current velocity, salinity and temperature measured at several fixed stations in the lagoon. The range of scores at the stations are: for temperature between −0.8 to +1.2°C, for salinity from −0.2 to 5 PSU, for sea level 0.1 m. The lagoon is dominated by an estuarine vertical circulation due to a double opening at the lagoon mouth and sustained by multiple sources of freshwater inputs. The non-linear interactions among the tidal forcing, the wind and the freshwater inputs affect the lagoon circulation at both seasonal and daily time scales. The sensitivity of the circulation to the forcings was analyzed with several sensitivity experiments done with the exclusion of the tidal forcing and different configurations of the river connections. GOLFEM was designed to resolve the lagoon dynamics at high resolution in order to evaluate the potential effects on the clam farming of two proposed scenarios of human intervention on the morphology of the connection with the sea. We calculated the changes of the lagoon current speed and salinity, and using opportune fitness indexes related to the clams physiology, we quantified analytically the effects of the interventions in terms of extension and persistence of areas of the clams optimal growth. The results demonstrate that the correct management of this kind of fragile environment relies on both long-term (intervention scenarios) and short-term (coastal flooding forecasts and potential anoxic conditions) modeling, based on a flexible tool that is able to consider all the recorded human interventions on the river connections. This study also demonstrates the importance of designing a seamless chain of models that are capable of integrating local effects into the coarser operational oceanographic models

The colon epithelium as a target for the intracellular antioxidant activity of hydroxytyrosol: a study on rat colon explants

Oxidative stress is involved in the genesis and progress of many disorders of the gastrointestinal (GI) tract. In particular, the colon epithelium is one of the GI tract segments more exposed to pro-oxidant conditions. We aimed to study the intracellular antioxidant activity of hydroxytyrosol (HT), one of the most potent natural antioxidant phenolic compounds typically present in olive oil, directly on the colon epithelium, under basal physiological and pro-oxidant conditions. Our approach was based on the application of in situ confocal microscopy on rat colon explants loaded with the fluorescent probe 5-(and-6)-chloromethyl-2’,7’-dichlorodihydrofluoresceindiacetate, which is sensitive to intracellular oxidative stress. In the intact mucosa, HT exerted a dose-dependent decrease of the basal intracellular reactive oxygen species (ROS) production of superficial colonocytes. Also, it induced a direct dose-dependent antioxidant action on the colon mucosa exposed to a pro-oxidant condition such as the H2O2 challenge. The effect of 100 µM HT was comparable to that of 10 µM Trolox, which is widely used as a standard in in vitro assays for the determination of antioxidant activity. The intracellular antioxidant activity of HT on the intact mucosa was also tested against tert-butyl peroxide, another pro-oxidant. The results show that HT can directly contribute to the redox balance of colonic epithelium by reducing ROS in both basal and pro-oxidant conditions, and support the potential of HT as a functional food ingredient with applications in protecting the intestinal mucosa against oxidative stress

Label-free biomechanical nanosensor based on LSPR for biological applications

A label-free localized surface plasmon resonance (LSPR)-based biosensor exploiting gold nanorods (ONRs) is proposed and demonstrated. For this aim, 35 +/- 5 nm long and 20 +/- 4 thick GNRs spaced by a few nanometers thick polyelectrolytes (PE) from a gold thin film was analyzed and synthesized. The morphology of the GNRs, the plasmon properties of GNRs, swelling of PE layers and the wettability of the surfaces were characterized by transmission and scanning electron microscopy, spectroscopic reflectivity and contact angle measurements, respectively. Indeed, when immersed in a phosphate buffer saline solution, the GNRs-PE-gold system shows an optical shift of the LSPR wavelength. This shift was found to correspond to a vertical swelling of about 2 nm, demonstrating the extreme sensitivity of the biosensor. Finally, we show that LSPR measurements can be used to detect dynamic resonance changes in response to both thickness and buffer solution, while the hydrophobic behavior of the surface can be exploited for reducing the number of liquid analytes in clinical biosensing application. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen