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At least 397 records · Page 22Linked to original sources
PubMed2001

Cysteine string proteins are associated with cortical granules of Xenopus laevis oocytes.

Cysteine string proteins (csps) are associated with secretory organelles in a wide range of eukaryotic cells. Functional studies of these proteins indicate that they subserve one or more vital steps in the pathway of regulated exocytosis. Here, we document the presence of csps in fully grown (stage VI) oocytes of the frog, Xenopus laevis. Both Northern and immunoblot data support the conclusion that csps are expressed in these cells. In addition, immunoreactive csp is seen even at the earliest stage of oocyte development, namely, in stage I oocytes. Finally, immunoblot and immunocytochemical results indicate that csps are associated with cortical granules of stage II-VI oocytes. These observations suggest that csps participate in the cortical reaction that underlies the sustained block to polyspermy in Xenopus eggs. Moreover, because of the relative ease of manipulating cells as large as Xenopus oocytes, this system harbors considerable promise as a model for studying the role of csps and other proteins in exocytotic events.

Animals↗
PubMed1998

Munc-18-1 and cysteine string protein (csp) in pinealocytes of the gerbil pineal gland.

Mammalian pinealocytes contain several synaptic membrane proteins which probably play a role in the targeting and exocytosis of secretory vesicles, in particular of synaptic-like microvesicles (SLMVs). The latter are considered as the endocrine equivalent of neuronal synaptic vesicles. By means of immunocytochemical techniques and immunoblot analyses, we now show that two further key components of the molecular apparatus regulating neurotransmitter release are present in the gerbil pineal gland, i.e., munc-18-1 and cysteine string protein (csp). In addition to varicosities of nerve fibres, munc-18-1 and csp could be localized to pinealocytes where both proteins were markedly enriched in process swellings. When using antibodies against csp for an immunogold electron-microscopic study of pinealocytes, gold particles consistently decorated profiles of pleomorphic SLMVs. Interestingly, we found that also the cytosolic protein munc-18, which is partially recruited to the plasmalemma in neurons, was associated to a significant extent with SLMVs of pinealocytes and synaptic vesicles of neurons, respectively. This localization implies that munc-18 at least partially exerts its regulatory functions while being bound to secretory vesicle membranes. Our results indicate that in endocrine cells such as pinealocytes the synaptic proteins munc-18-1 and csp play essential roles during the life cycle of SLMVs.

Animals↗
PubMed2001

The value of laparoscopy in the diagnosis and therapy of violin-string like perihepatic nonpostoperative adhesions.

We report three cases of Fitrz-Hugh Curtis syndrome (FHCs) that were diagnosed laparoscopically and showed microbiological or serological evidence of chlamydial infection. The case histories underscore the part played by abdominal right quadrant symptoms. In all three cases, right quadrant pain and tenderness constituted the presenting features. The patients were thought to have acute cholecystitis or acute appendicitis, but investigations proved negative. Laparoscopy was the key to the diagnosis, revealing the violin-string-like perihepatic adhesions typical of this syndrome. Lysis of the adhesions resolved the patients' symptoms of persistent severe abdominal pain. In the first case, the pain lessened dramatically only after the third operation, when the perihepatic adhesions were lysed. In the two other cases, the lysis was performed laparoscopically by fulguration and cutting. We consider this procedure to be an excellent therapeutic modality for the pain associated with FHCs.

Abdominal Pain↗
PubMed2004

"Insightful" string-pulling in Grey parrots (Psittacus erithacus) is affected by vocal competence.

Four Grey parrots (Psittacus erithacus) were tested on their ability to obtain an item suspended from a string such that mutiple, repeated, coordinated beak-foot actions were required for success (e.g., Heinrich 1995). Those birds with little training in referential English requests (e.g. "I want X") succeeded, whereas birds who could request the suspended item failed to obtain the object but engaged in repeated requesting.

Animals↗
PubMed1982

A method of closing urethral fistulae using a purse-string or interrupted silk sutures.

A simple method of closure of urethral fistulae is described, using a purse-string suture for small fistulae and serial silk sutures for larger fistulae, with a skin flap for cover. No urethral catheter is required and hospitalisation is reduced to 3-4 days. Twenty cases have been treated in this way with no recurrence of the fistula and no stricture formation.

Humans↗
PubMed1990

Sensillum development in the absence of cell division: the sensillum phenotype of the Drosophila mutant string.

We have investigated sensillum development in Drosophila embryos homozygous for mutations in the locus string (stg). In these embryos, cell division is blocked following blastoderm formation. This permits a study of the differentiative fate of undivided precursor cells, in particular those giving rise to the larval sensory organs (sensilla). Of the different cell fates normally represented in the sensilla (i.e., sensory neuron, thecogen cell, trichogen cell, tormogen cell, glia cell), only the phenotype of sensory neurons is expressed morphologically in stg embryos, suggesting that the neuronal fate predominates over the fates of the nonneuronal accessory cells. Consistent with this finding, the P element-lacZ insertion A1-2nd-29, which is a marker for trichogen and tormogen cells in the wild-type embryo, is not expressed in the body wall of the stg embryo. Some sensillum precursor cells appear to express a mixed fate in stg mutants: They express antigens (recognized by the monoclonal antibodies 22C10 and 21A6) which in the wild-type appear in separate cells (sensory neurons and thecogen cell, respectively). The differentiation of undivided cells in stg embryos is not restricted to the peripheral nervous system; in all types of tissues analyzed in this study (e.g., epidermis, intestine, muscle, CNS), precursor cells express characteristics normally exhibited by their progeny.

Animals↗
PubMed1989

The yeast pyruvate kinase gene does not contain a string of non-preferred codons: revised nucleotide sequence.

The sequence of the gene encoding pyruvate kinase from Saccharomyces cerevisiae was re-determined because of failures with oligonucleotide-directed mutagenesis experiments involving a region thought to contain a string of five contiguous non-preferred codons. This region was found to be difficult to sequence and was shown to have three extra bases when compared with the published sequence [(1983) J. Biol. Chem. 258, 2193-2201]. The revised sequence demonstrates that the yeast pyruvate kinase gene does not have a cluster of non-preferred codons, and that it therefore is not an example of the class of genes which possibly exhibit translational control by the presence of non-preferred codons.

Amino Acid Sequence↗
PubMed1996

Widespread expression of human cysteine string proteins.

We present the nucleotide and deduced amino acid sequence of a human systeine string protein (csp) and a unique truncated csp variant that derives from the retention of an exonic sequence that introduces a premature, in-frame stop codon. Low stringency Southern analysis is compatible with the presence of a single human csp gene. Northern analysis reveals that human csp mRNA has both a more heterogeneous size distribution and a more widespread tissue distribution than previously reported for other csps. Exemplifying this is the fact that csp immunoreactivity is detected in Triton X-114 extracts of human blood, an observation which may facilitate blood-based diagnostic assays of csp status in man.

Amino Acid Sequence↗
PubMed1990

The three postblastoderm cell cycles of Drosophila embryogenesis are regulated in G2 by string.

The string (stg) locus of Drosophila encodes a factor that is thought to trigger mitosis by activating the p34cdc2 protein kinase. stg is required for mitosis early in development and is transcribed in a dynamic pattern that anticipates the pattern of embryonic cell divisions. Here we show that differential cell cycle regulation during postblastoderm development (cell cycles 14-16) occurs in G2. We demonstrate that stg mRNA expressed from a heat shock promotor triggers mitosis, and an associated S phase, in G2 cells during these cycles. Hence, differential cell cycle timing at this developmental stage is controlled by stg. Finally, we use heat-induced stg expression to alter the normal pattern of embryonic mitoses. Surprisingly, the complex mitotic pattern evident during normal development is not essential for many features of pattern formation or for viability.

Animals↗
PubMed1987

Effects of concurrent spatial and verbal memory loads on serial position functions of laterally presented letter strings.

In this study the influence of visuospatial and verbal memory loads on the identification of laterally presented letter strings was investigated. In the asymmetry task without concurrent loads, a clear right visual field advantage for letter identification was obtained. Hemisphere-specific effects due to concurrent loads were particularly observed when the difficulty of the load tasks was increased. The effects of visuospatial loads were found to be sex related, suggesting that under heavy load conditions mental rotation selectively overloads the processing capacity of the right hemisphere in males, while in females capacity limitations were observed in both hemispheres. Concurrent visuospatial loads produced more facilitation (or less interference) for letters in the outermost positions of each visual field than for letters in the innermost positions of each visual field. The results of the verbal memory load tasks revealed that an easy verbal load task facilitated performance which was particularly manifest for the right-most letter of both the left visual field and the right visual field. A difficult verbal memory load task interfered with recognition accuracy of letters which was most marked for the center letter in the right visual field. Letter position effects obtained in this study were interpreted in terms of various processing mechanisms influencing the serial position curves.

Adult↗
PubMed1995

Cysteine string proteins and presynaptic function.

A brief review is presented of investigations of a novel family of synaptic vesicle proteins, the cysteine string proteins (csps). Studies of csp mutants in Drosophila reveal that csps are crucial components of the excitation-secretion machinery at nerve terminals. Current data cannot distinguish between a primary role of csps in modulating calcium ion influx at the nerve terminal versus a more-direct role in the exocytotic cascade. In this context, the remarkable post-translational modification of csps, namely the fatty acylation of as many as 12 of the 13 cysteine residues of the Torpedo protein, suggests that csps may participate more directly in the process of membrane fusion that underlies exocytosis. This would be achieved by using the fatty acyl chains of the csps as templates for 'lipid flow' that would allow the fusion of vesicular and plasma membranes. These hypotheses provide a useful framework for empirical tests of the role of csps in nerve terminal function.

Animals↗
PubMed2005

Symbol-string sensitivity and adult performance in lexical decision.

In this study of adult readers, we used a symbol-string task to assess participants' sensitivity to the position of briefly presented, non-alphabetic but letter-like symbols. We found that sensitivity in this task explained a significant proportion of sample variance in visual lexical decision. Based on a number of controls, we show that this relationship cannot be explained by other factors including: chronological age, intelligence, speed of processing and/or concentration, short term memory consolidation, or fixation stability. This approach represents a new way to elucidate how, and to what extent, individual variation in pre-orthographic visual and cognitive processes impinge on reading skills, and the results suggest that limitations set by visuo-spatial processes constrain visual word recognition.

Adult↗
PubMed2006

The cysteine string protein multimeric complex.

Cysteine string protein (CSPalpha) is a member of the cellular folding machinery that is located on regulated secretory vesicles. We have previously shown that CSPalpha in association with Hsc70 (70kDa heat shock cognate protein) and SGT (small glutamine-rich tetratricopeptide repeat domain protein) is a guanine nucleotide exchange factor (GEF) for G(alphas). Association of this CSPalpha complex with N-type calcium channels, a channel key in coupling calcium influx with synaptic vesicle exocytosis, triggers tonic G protein inhibition of the channels. Syntaxin 1A, a plasma membrane SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) critical for neurotransmission, coimmunoprecipitates with the CSPalpha/G protein/N-type calcium channel complex, however the significance of syntaxin 1A as a component of this complex remains unknown. In this report, we establish that syntaxin 1A interacts with CSPalpha, Hsc70 as well as the synaptic protein interaction (synprint) region of N-type channels. We demonstrate that huntingtin(exon1), a putative biologically active fragment of huntingtin, displaces both syntaxin 1A and CSPalpha from N-type channels. Identification of the protein components of the CSPalpha/GEF system is essential in establishing its precise role in synaptic transmission.

Animals↗
PubMed2005

Prediction of siRNA functionality using generalized string kernel and support vector machine.

Small interfering RNAs (siRNAs) are becoming widely used for sequence-specific gene silencing in mammalian cells, but designing an effective siRNA is still a challenging task. In this study, we developed an algorithm for predicting siRNA functionality by using generalized string kernel (GSK) combined with support vector machine (SVM). With GSK, siRNA sequences were represented as vectors in a multi-dimensional feature space according to the numbers of subsequences in each siRNA, and subsequently classified with SVM into effective or ineffective siRNAs. We applied this algorithm to published siRNAs, and could classify effective and ineffective siRNAs with 90.6%, 86.2% accuracy, respectively.

Algorithms↗
PubMed2005

The string method of burst identification in neuronal spike trains.

The activity state of neuronal networks can be characterized by the spatial-temporal grouping of their action potentials given a sufficiently large simultaneous recording sample. A sequence of action potentials (spike train) often has high frequency spike episodes that are generally called bursts. However, bursts are difficult to quantify and require operational definitions that reflect the type of activity and the interest of the experimenter. This paper presents a simple method for defining bursts as strings of spikes with only two parameters: a minimum number of spikes per burst and a maximum interspike interval. These two values represent a simple parameterization that is adequate for the description of temporal grouping in spike trains. Because this method has a minimal computation time, it allows implementation of burst analysis in real-time, including statistical changes in burst variables, histograms of burst types, and patterns in combinations of burst variables.

Action Potentials↗
PubMed2004

Penile strangulation treated with the modified string method.

Penile strangulation by a nonmetallic or thin metallic ring is easily overcome by severing the object, but a heavy metal ring causing penile strangulation is very difficult to sever. Here we report 2 cases of penile strangulation by metal rings, involving a 38-year-old man and a 44-year-old man, both of whom were treated with the modified string method and glandular puncture.

Adult↗
PubMed2004

Poly-guanosine strings improve cellular uptake and stimulatory activity of phosphodiester CpG oligonucleotides in human leukocytes.

CpG-oligonucleotides (CpG-ODN) have been shown to exert strong immuno-stimulatory effects through activation of Toll-like receptor 9 (TLR-9). However, TLR-9 triggering takes place in endosomal compartments and thus CpG-ODN have to be taken up prior to signal transduction. We here report that 3'-poly-guanosine strings can improve cellular internalisation of phosphodiester but not of phosphorothioate CpG-ODN. Improved cellular uptake correlated with enhanced IL-6 secretion and proliferation of PBMC. Also, TLR-9 transfected HEK293 cells were activated more efficiently by poly-guanosine modified CpG-ODN. The results indicate that the synthesis of stimulatory CpG-ODN based on a phosphodiester backbone is feasible via such poly-guanosine substitutions. In addition we observed that phosphorothioate ODN were able to exert immunostimulatory effects independent of the presence of CpG motifs.

Adjuvants, Immunologic↗