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At least 235 records · Page 13Linked to original sources
PubMed1998

Adaptations of a tropical swamp worm, alma emini, for subsistence in a H2S-rich habitat: evolution of endosymbiotic bacteria, sulfide metabolizing bodies, and novel processes of elimination of neutralized sulfide complexes

The epithelial cell lining of the respiratory groove of Alma emini, an oligochaete glossoscolecid worm that lives in a hydrogen sulfide (H2S)-rich tropical swamp, was investigated by transmission electron microscopy to determine the underlying structural adaptations which enable the worm to subsist in a highly inimical habitat. The epithelium of the respiratory groove is made up of squamous cells with a highly amplified free epithelial surface. The cells are tightly packed with electron dense sulfur metabolizing bodies (SMBs) and contain endosymbiotic bacteria. Presence of sulfur in the electron dense SMBs was confirmed by X-ray microanalysis. Certain eukaryotic cells with prominent filopodia-like cytoplasmic extensions were observed under the epithelial cells and in the muscle tissue. The cells contained numerous heteromorphic endosymbiotic bacteria and scattered SMBs. Both the SMBs and the bacteria are reckoned to be involved in scavenging and detoxifying H2S. The removal of sulfide complexes was observed to occur through excision of blebs formed by epithelial cell membrane elaborations and by exocytosis of crystalline-like particles. These adaptive stratagems generally correspond with those that have been adopted by many marine and hydrothermal vent organisms that occupy sulfide-rich biomes. The congruent adaptive stratagems and ultrastructural morphologies in such a diverse community of organisms have been imposed by a common need to neutralize the insidious effects of H2S in their environments. Copyright 1998 Academic Press.

Journal Article↗
PubMed1996

Renaut bodies. Benign disease process mimicking neurotropic tumor infiltration.

BACKGROUND: Mohs micrographic surgery maximizes the potential for complete tumor removal with normal tissue preservation through the histologic examination of all tissue margins. One component of the histologic examination is the evaluation of excised nerves for the presence of tumor infiltration. During such an evaluation, a subperineurial structure was noted. OBSERVATION: Further investigation displayed a discrete, loosely textured, cell-sparse, whorled, subperineurial structure that invaginated into the peripheral nerve. Inflammation was absent and the nuclei were monomorphous. These findings are those seen with Renaut bodies. CONCLUSIONS: Renaut bodies are found at sites of nerve compression. Mechanical factors are thought to play a major role in pathogenesis. Cells comprising the Renaut body are fibroblasts of perineurial origin with the extracellular matrix comprised of collagen fibrils, basal lamina material, and oxytalan filaments. Renaut bodies are important insofar as the surgeon must recognize that they are benign. Histologic characteristics that differentiate Renaut bodies from malignant neurotropic infiltration are: (a) a cell-sparse mass, (b) absence of nuclear atypia, (c) less than expected inflammatory infiltrate, and (d) well-defined borders.

Actin Cytoskeleton↗
PubMedDate not supplied

[Effect of retabolil, biosed and vitreous body on reparative processes in the heart of rats with experimental myocardial infarction].

Influence of retabolilum, biossedum and corpus vitreum on the inflammation and reparation in the rat heart with experimental infarction has been investigated. It is shown that retabolilum has the most pronounced reparation effect. At the same time biossedum has a slight effect on the reparative processes and corpus vitreum does not influence it al all. It is also found that the most pronounced action of retabolilum has been observed by the 12th day of infarction.

Animals↗
PubMed1999

Ecdysone-regulation of synthesis and processing of fat body protein 1, the larval serum protein receptor of Drosophila melanogaster.

At the end of the third larval instar of Drosophila melanogaster, larval serum proteins 1 and 2 (LSP-1 and -2) are taken up by cells of the fat body. Here, we show that the product of the ecdysteroid-inducible gene Fbp-1 (Fat Body Protein 1) is the receptor that binds LSP-1. Transcription and translation of Fbp-1 is stage-specifically restricted to the end of the third larval instar, starting around 99 h after egg laying. Expression of Fbp-1 is induced by a low level of 20-hydroxy-ecdysone (>/= 10-7 m). After translation, the FBP-1 protein is thought to be proteolytically cleaved in three subsequent steps. The final cleavage step is delayed by 6 h and relies on a higher concentration of ecdysone (>/= 10-5 m). Therefore, 20-hydroxy-ecdysone regulates Fbp-1 expression and function at two different levels. To the best of our knowledge, this study is the first to date to demonstrate two distinct functions for different concentrations of a steroid hormone on a single biochemical process.

Amino Acid Sequence↗
PubMed2007

Sequential use of mushroom body neuron subsets during drosophila odor memory processing.

Drosophila mushroom bodies (MB) are bilaterally symmetric multilobed brain structures required for olfactory memory. Previous studies suggested that neurotransmission from MB neurons is only required for memory retrieval. Our unexpected observation that Dorsal Paired Medial (DPM) neurons, which project only to MB neurons, are required during memory storage but not during acquisition or retrieval, led us to revisit the role of MB neurons in memory processing. We show that neurotransmission from the alpha'beta' subset of MB neurons is required to acquire and stabilize aversive and appetitive odor memory, but is dispensable during memory retrieval. In contrast, neurotransmission from MB alphabeta neurons is only required for memory retrieval. These data suggest a dynamic requirement for the different subsets of MB neurons in memory and are consistent with the notion that recurrent activity in an MB alpha'beta' neuron-DPM neuron loop is required to stabilize memories formed in the MB alphabeta neurons.

Animals↗
PubMed2003

DnaK and DnaJ facilitated the folding process and reduced inclusion body formation of magnesium transporter CorA overexpressed in Escherichia coli.

Overexpression of CorA, the major magnesium transporter from bacterial inner membrane, in Escherichia coli resulted in the synthesis of 60mg of protein per liter of culture, most of which however was in the form of inclusion bodies. The levels of inclusion body formation were reduced by lowering the cell culture temperature. To dissect CorA inclusion body formation and the folding process involved, we co-expressed the protein with various chaperones and other folding modulators. Expression of DnaK/DnaJ (Hsp70) prevented inclusion bodies from forming and resulted in the integration of more CorA into the membrane. GroEL/GroES (Hsp60/Hsp10) were less effective at reducing CorA inclusion body formation. Co-expression with either Ffh/4.5S-RNA, the signal recognition particle, or SecA, the ATPase that drives protein insertion into the membrane, had little effect on CorA folding. These results indicate: (1) that CorA inclusion bodies form immediately after synthesis at 37 degrees C, (2) that CorA solubility in the cytosol can be increased by co-expressing a chaperone system, (3) membrane targeting is probably not a rate-limiting factor, and (4) that membrane insertion becomes a limitation only when large amounts of soluble CorA are present in the cytosol. These co-expression systems can be used for producing other membrane proteins in large quantities.

Cation Transport Proteins↗
PubMed1993

Is the selective information processing of food and body words specific to patients with eating disorders?

The selective processing of food- and body size-related information was investigated using a modified version of the Stroop task. Anorexic and bulimic patients and matched female controls were compared on the basis of categorical (diagnosis), dimensional (restraint and drive for thinness) criteria, or both. The findings suggest that the phenomenon assessed by the Stroop paradigm is not exclusive to patients with a clinical eating disorder, but patients and those control subjects who are restrained eaters with a high drive for thinness share a selective processing of information related to shape and eating. The discussion focuses on the implications of these findings.

Anorexia Nervosa↗
PubMed1998

No evidence for a selective processing of subliminally presented body words in restrained eaters.

OBJECTIVE: In the present study, it was hypothesized that restrained eating subjects will show an attentional bias for body shape and weight words during the automatic stage of information processing and not during the strategic or controlled stage. METHOD: Thirteen high restrained and fifteen low restrained eaters participated in the experiment. Body shape and weight words as well as neutral words were presented both supraliminally and subliminally during a computerized Stroop task. RESULTS: The high restrained eaters did not show distortions in the processing of body shape and weight stimuli; neither an early automatic processing priority nor a pattern of strategic processing selectivity characterizes restrained eaters. DISCUSSION: The absence of cognitive distortions in the processing of body shape and weight information might point to a qualitative difference between normal restrained eaters and subjects with eating disorders of clinical severity.

Adult↗
PubMed1998

Conscious and preconscious processing of food, body weight and shape, and emotion-related words in women with anorexia nervosa.

OBJECTIVE: The present study was conducted to extend prior research on attention toward food and body weight and shape-related stimuli in women with eating disorders. METHOD: A modified Stroop color-naming task was completed by women with anorexia nervosa and by control females subdivided on a measure of dietary restraint. Eating disorder-relevant word categories included words connoting fatness, words connoting thinness, low caloric density food words, high caloric density food words, and neutral, control words. Valence effects were controlled for by including positively and negatively valenced emotion words. Stimuli were presented under both unmasked and masked conditions. RESULTS: Using unmasked stimuli, patients with anorexia nervosa, but not unrestrained or restrained eaters, had delayed color-naming latencies for both thin and fat word categories and, to a lesser extent, for high caloric density food words. No differences were observed with masked stimuli. DISCUSSION: Our findings suggest that both thinness and fatness are especially salient to women with anorexia. The lack of effects for emotion words suggests that these findings do not reflect a valence effect. We found no evidence for preconscious attentional biases in the masked condition.

Adolescent↗
PubMed1994

Differential distribution of two Ca(2+)-dependent and -independent K+ channels throughout receptive and basolateral membranes of bullfrog taste cells.

We could identify two types of K+ channels, of 80 and 40 pS conductance, respectively, in the bullfrog taste cell membrane using excised and cell-attached configurations of the patch-clamp technique. The taste cell membrane could be divided into four membrane parts--receptive area, apical process, cell body and proximal process. The 80-pS K+ channels were dependent on voltage and Ca2+ and were located exclusively on the receptive membrane and the apical process membrane. The 40-pS K+ channels were independent of voltage and Ca2+. The open probability of 40-pS K+ channels was decreased by the simultaneous presence of cyclic adenosine monophosphate (cAMP) and adenosine triphosphate (ATP), and the suppressive effect was antagonized by protein kinase inhibitor (PKI). Although 40-pS K+ channels were found in a high density on the receptive and apical process membranes, the channels also were present in the other two parts of the taste cell membrane. These results suggest that the two different types of K+ channel in the bullfrog taste cells may play different roles in gustatory transduction.

Adenosine Triphosphate↗
PubMed2006

Representation of body identity and body actions in extrastriate body area and ventral premotor cortex.

Although inherently linked, body form and body action may be represented in separate neural substrates. Using repetitive transcranial magnetic stimulation in healthy individuals, we show that interference with the extrastriate body area impairs the discrimination of bodily forms, and interference with the ventral premotor cortex impairs the discrimination of bodily actions. This double dissociation suggests that whereas extrastriate body area mainly processes actors' body identity, premotor cortex is crucial for visual discriminations of actions.

Adult↗
PubMed2003

Out-of-body experience and autoscopy of neurological origin.

During an out-of-body experience (OBE), the experient seems to be awake and to see his body and the world from a location outside the physical body. A closely related experience is autoscopy (AS), which is characterized by the experience of seeing one's body in extrapersonal space. Yet, despite great public interest and many case studies, systematic neurological studies of OBE and AS are extremely rare and, to date, no testable neuroscientific theory exists. The present study describes phenomenological, neuropsychological and neuroimaging correlates of OBE and AS in six neurological patients. We provide neurological evidence that both experiences share important central mechanisms. We show that OBE and AS are frequently associated with pathological sensations of position, movement and perceived completeness of one's own body. These include vestibular sensations (such as floating, flying, elevation and rotation), visual body-part illusions (such as the illusory shortening, transformation or movement of an extremity) and the experience of seeing one's body only partially during an OBE or AS. We also find that the patient's body position prior to the experience influences OBE and AS. Finally, in five patients, brain damage or brain dysfunction is localized to the temporo-parietal junction (TPJ). These results suggest that the complex experiences of OBE and AS represent paroxysmal disorders of body perception and cognition (or body schema). The processes of body perception and cognition, and the unconscious creation of central representation(s) of one's own body based on proprioceptive, tactile, visual and vestibular information-as well as their integration with sensory information of extrapersonal space-is a prerequisite for rapid and effective action with our surroundings. Based on our findings, we speculate that ambiguous input from these different sensory systems is an important mechanism of OBE and AS, and thus the intriguing experience of seeing one's body in a position that does not coincide with its felt position. We suggest that OBE and AS are related to a failure to integrate proprioceptive, tactile and visual information with respect to one's own body (disintegration in personal space) and by a vestibular dysfunction leading to an additional disintegration between personal (vestibular) space and extrapersonal (visual) space. We argue that both disintegrations (personal; personal-extrapersonal) are necessary for the occurrence of OBE and AS, and that they are due to a paroxysmal cerebral dysfunction of the TPJ in a state of partially and briefly impaired consciousness.

Body Image↗