Search results for "BIOCHEMISTRY"

Regulation of motility of cells from marine sponges by calcium ions

1996

Sponges are known not to contain muscle and nerve cells. Since sponge cells are characterized by high motility we determined the effect of intracellular calcium ion concentration ([Ca2+]i) on their motility. Addition of the Ca2+ ionophore ionomycin to dissociated cells from the marine sponge Suberites domuncula caused in Ca(2+)-containing artificial seawater (ASW) an increase in motility from 0.2 micron/min (absence of the ionophore) to 3.7 microns/min (presence of ionomycin). When the experiments were performed in Ca(2+)-free medium, no effect of ionomycin could be observed. In parallel experiments the changes of [Ca2+]i using the dye Fura-2 were measured. The experiments revealed that ion…

Emergence and Disappearance of an Immune Molecule, an Antimicrobial Lectin, in Basal Metazoa

2003

Sponges (phylum Porifera) represent the evolutionarily oldest metazoans that comprise already a complex immune system and are related to the crown taxa of the protostomians and the deuterostomians. Here, we demonstrate the existence of a tachylectin-related protein in the demosponge Suberites domuncula, termed Suberites lectin. The MAPK pathway was activated in response to lipopolysaccharide treatment of the three-dimensional cell aggregates, the primmorphs; this process was abolished by the monosaccharide D-GlcNAc. The cDNA encoding the S. domuncula lectin was identified and cloned; it comprises 238 amino acids (26 kDa) in the open reading frame. The deduced protein has one potential trans…

Factors behind Leisure-Time Physical Activity Behavior Based on Finnish Twin Studies: The Role of Genetic and Environmental Influences and the Role o…

2014

Different approaches are being taken to clarify the role of various factors in the development of physical activity behaviors. Genetic studies are a new area of physical activity research and also the motives for physical activity have been widely studied. The purpose of this paper is to review the findings emerging from the longitudinal genetic studies on leisure-time physical activity and to evaluate the associations between motivational factors and leisure-time physical activity. The focus is to review recent findings of longitudinal Finnish twin studies. The results of the latest longitudinal Finnish twin studies point to the existence of age-specific genetic and environmental influence…

Modeling multipartite virus evolution: the genome formula facilitates rapid adaptation to heterogeneous environments

2020

Multipartite viruses have two or more genome segments, and package different segments into different particle types. Although multipartition is thought to have a cost for virus transmission, its benefits are not clear. Recent experimental work has shown that the equilibrium frequency of viral genome segments, the setpoint genome formula (SGF), can be unbalanced and host-species dependent. These observations have reinvigorated the hypothesis that changes in genome-segment frequencies can lead to changes in virus-gene expression that might be adaptive. Here we explore this hypothesis by developing models of bipartite virus infection, leading to a threefold contribution. First, we show that th…

Recent Advances in Forward Brillouin Scattering: Sensor Applications

2022

In-fiber opto-mechanics based on forward Brillouin scattering has received increasing attention because it enables sensing the surrounding of the optical fiber. Optical fiber transverse acoustic resonances are sensitive to both the inner properties of the optical fiber and the external medium. A particularly efficient pump and probe technique—assisted by a fiber grating—can be exploited for the development of point sensors of only a few centimeters in length. When measuring the acoustic resonances, this technique provides the narrowest reported linewidths and a signal-to-noise ratio better than 40 dB. The longitudinal and transverse acoustic velocities—normalized with the fiber radius—can b…

Grain Composition and Functional Ingredients of Barley Varieties Created in Latvia

2015

Abstract Cereals, including barley, have been recognised as functional foods that provide beneficial effect on the health of the consumer and decrease the risk of various diseases. The aim of investigation was to determine the grain composition of barley varieties and perspective breeding lines bred in Latvia and to evaluate its functional ingredients. The results of analysis showed that protein content among varieties ranged from 106.6-146.8 g·kg-1, total dietary fibre 187.4-208.2 g·kg-1, β-glucans 42.8 g-49.4 g·kg-1, and amount of α-tocopherol 6.03-8.93 mg·kg-1. The sum of essential amino acids in barley grain samples was from 32.90 g·kg-1 to 38.71 g·kg-1. All varieties of hulled and hull…

Boire très chaud pourrait diminuer notre capacité à bien percevoir les saveurs

2021

The chemical composition of the aerial parts essential oil of Achillea cretica L. (Asteraceae) growing wild in Crete (Greece)

2022

Achillea cretica (L.) (Asteraceae) is a suffruticosa camefite plant, mainly distributed in Crete, Aegean Islands, and eastern Mediterranean area. In the present study, the chemical composition of the essential oil from aerial parts of a not previously investigated accession of Achillea cretica, collected in Crete, was analysed by GC-MS. The results showed the presence of large quantity of α-bisabolol (53.88%) followed by the related compound α-bisabolol-oxide (2.76%), and spathulenol (5.94%). Based on the composition of the essential oils of all the other Achillea taxa, several consideration have been carried out.

α-Conotoxins EpI and AuIB switch subtype selectivity and activity in native versus recombinant nicotinic acetylcholine receptors

2003

The Xenopus laevis oocyte expression system was used to determine the activities of alpha-conotoxins EpI and the ribbon isomer of AuIB, on defined nicotinic acetylcholine receptors (nAChRs). In contrast to previous findings on intracardiac ganglion neurones, alpha-EpI showed no significant activity on oocyte-expressed alpha3beta4 and alpha3beta2 nAChRs but blocked the alpha7 nAChR with an IC50 value of 30 nM. A similar IC50 value (103 nM) was obtained on the alpha7/5HT3 chimeric receptor stably expressed in mammalian cells. Ribbon AuIB maintained its selectivity on oocyte-expressed alpha3beta4 receptors but unlike in native cells, where it was 10-fold more potent than native alpha-AuIB, had…

Profiling Dopamine-Induced Oxidized Proteoforms of β-synuclein by Top-Down Mass Spectrometry

2021

The formation of multiple proteoforms by post-translational modifications (PTMs) enables a single protein to acquire distinct functional roles in its biological context. Oxidation of methionine residues (Met) is a common PTM, involved in physiological (e.g., signaling) and pathological (e.g., oxidative stress) states. This PTM typically maps at multiple protein sites, generating a heterogeneous population of proteoforms with specific biophysical and biochemical properties. The identification and quantitation of the variety of oxidized proteoforms originated under a given condition is required to assess the exact molecular nature of the species responsible for the process under investigation…