3,797 research outputs found
On the Cognition of States of Affairs
The theory of speech acts put forward by Adolf Reinach in his "The A Priori Foundations of the Civil Law" of 1913 rests on a systematic account of the ontological structures associated with various different sorts of language use. One of the most original features of Reinach's account lies in hIs demonstration of how the ontological structure of, say, an action of promising or of commanding, may be modified in different ways, yielding different sorts of non-standard instances of the corresponding speech act varieties. The present paper is an attempt to apply this idea of standard and modified instances of ontological structures to the realm of judgement and cognition, and thereby to develop a Reinachian theory of how intentionality is mediated through language in acts of thinking and speaking
The major myosin-binding domain of skeletal muscle MyBP-C (C protein) resides in the COOH-terminal, immunoglobulin C2 motif.
A common feature shared by myosin-binding proteins from a wide variety of species is the presence of a variable number of related internal motifs homologous to either the Ig C2 or the fibronectin (Fn) type III repeats. Despite interest in the potential function of these motifs, no group has clearly demonstrated a function for these sequences in muscle, either intra- or extracellularly. We have completed the nucleotide sequence of the fast type isoform of MyBP-C (C protein) from chicken skeletal muscle. The deduced amino acid sequence reveals seven Ig C2 sets and three Fn type III motifs in MyBP-C. alpha-chymotryptic digestion of purified MyBP-C gives rise to four peptides. NH2-terminal sequencing of these peptides allowed us to map the position of each along the primary structure of the protein. The 28-kD peptide contains the NH2-terminal sequence of MyBP-C, including the first C2 repeat. It is followed by two internal peptides, one of 5 kD containing exclusively spacer sequences between the first and second C2 motifs, and a 95-kD fragment containing five C2 domains and three fibronectin type III motifs. The C-terminal sequence of MyBP-C is present in a 14-kD peptide which contains only the last C2 repeat. We examined the binding properties of these fragments to reconstituted (synthetic) myosin filaments. Only the COOH-terminal 14-kD peptide is capable of binding myosin with high affinity. The NH2-terminal 28-kD fragment has no myosin-binding, while the long internal 100-kD peptide shows very weak binding to myosin. We have expressed and purified the 14-kD peptide in Escherichia coli. The recombinant protein exhibits saturable binding to myosin with an affinity comparable to that of the 14-kD fragment obtained by proteolytic digestion (1/2 max binding at approximately 0.5 microM). These results indicate that the binding to myosin filaments is mainly restricted to the last 102 amino acids of MyBP-C. The remainder of the molecule (1,032 amino acids) could interact with titin, MyBP-H (H protein) or thin filament components. A comparison of the highly conserved Ig C2 domains present at the COOH-terminus of five MyBPs thus far sequenced (human slow and fast MyBP-C, human and chicken MyBP-H, and chicken MyBP-C) was used to identify residues unique to these myosin-binding Ig C2 repeats
Ocular transient receptor potential channel function in health and disease
Transient receptor potential (TRP) channels sense and transduce environmental
stimuli into Ca2+ transients that in turn induce responses essential for cell
function and adaptation. These non-selective channels with variable Ca2+
selectivity are grouped into seven different subfamilies containing 28
subtypes based on differences in amino acid sequence homology. Many of these
subtypes are expressed in the eye on both neuronal and non-neuronal cells
where they affect a host of stress-induced regulatory responses essential for
normal vision maintenance. This article reviews our current knowledge about
the expression, function and regulation of TRPs in different eye tissues. We
also describe how under certain conditions TRP activation can induce responses
that are maladaptive to ocular function. Furthermore, the possibility of an
association between TRP mutations and disease is considered. These findings
contribute to evidence suggesting that drug targeting TRP channels may be of
therapeutic benefit in a clinical setting. We point out issues that must be
more extensively addressed before it will be possible to decide with certainty
that this is a realistic endeavor. Another possible upshot of future studies
is that disease process progression can be better evaluated by profiling
changes in tissue specific functional TRP subtype activity as well as their
gene and protein expression
Baseline reef health surveys at Bangka Island (North Sulawesi, Indonesia) reveal new threats
Worldwide coral reef decline appears to be accompanied by an increase in the spread of hard coral diseases. However, whether this is the result of increased direct and indirect human disturbances and/or an increase in natural stresses remains poorly understood. The provision of baseline surveys for monitoring coral health status lays the foundations to assess the effects of any such anthropogenic and/or natural effects on reefs. Therefore, the objectives of this present study were to provide a coral health baseline in a poorly studied area, and to investigate possible correlations between coral health and the level of anthropogenic and natural disturbances. During the survey period, we recorded 20 different types of coral diseases and other compromised health statuses. The most abundant were cases of coral bleaching, followed by skeletal deformations caused by pyrgomatid barnacles, damage caused by fish bites, general pigmentation response and galls caused by cryptochirid crabs. Instances of colonies affected by skeletal eroding bands, and sedimentation damage increased in correlation to the level of bio-chemical disturbance and/or proximity to villages. Moreover, galls caused by cryptochirid crabs appeared more abundant at sites affected by blast fishing and close to a newly opened metal mine. Interestingly, in the investigated area the percentage of corals showing signs of ‘common’ diseases such as black band disease, brown band disease, white syndrome and skeletal eroding band disease were relatively low. Nevertheless, the relatively high occurrence of less common signs of compromised coral-related reef health, including the aggressive overgrowth by sponges, deserves further investigation. Although diseases appear relatively low at the current time, this area may be at the tipping point and an increase in activities such as mining may irredeemably compromise reef health.This research was partially funded by Coral Eye, which hosted FF and covered all field expenses. The non-profit organization Reef Check Italia Onlus sustained the cost for open source publication. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
L-Carnitine Reduces in Human Conjunctival Epithelial Cells Hypertonic- Induced Shrinkage through Interacting with TRPV1 Channels
Background/Aims: Ocular surface health depends on conjunctival epithelial
(HCjE) layer integrity since it protects against pathogenic infiltration and
contributes to tissue hydration maintenance. As the same increases in tear
film hyperosmolarity described in dry eye disease can increase corneal
epithelial transient receptor potential vanilloid type-1 (TRPV1) channel
activity, we evaluated its involvement in mediating an osmoprotective effect
by L-carnitine against such stress. Methods: Using siRNA gene silencing,
Ca2+imaging, planar patch- clamping and relative cell volume measurements, we
determined if the protective effects of this osmolyte stem from its
interaction with TRPV1. Results: TRPV1 activation by capsaicin (CAP) and an
increase in osmolarity to≈450 mOsM both induced increases in Ca2+levels. In
contrast, blocking TRPV1 activation with capsazepine (CPZ) fully reversed this
response. Similarly, L-carnitine (1 mM) also reduced underlying whole-cell
currents. In calcein-AM loaded cells, hypertonic-induced relative cell volume
shrinkage was fully blocked during exposure to L-carnitine. On the other hand,
in TRPV1 gene-silenced cells, this protective effect by L-carnitine was
obviated. Conclusion: The described L-carnitine osmoprotective effect is
elicited through suppression of hypertonic-induced TRPV1 activation leading to
increases in L-carnitine uptake through a described Na+-dependent L-carnitine
transporter
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