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1.
J Morphol ; 277(8): 1084-103, 2016 08.
Article in English | MEDLINE | ID: mdl-27354144

ABSTRACT

Although the circulatory system of arthropods has long been considered as rather simple, recent studies have demonstrated that in certain arthropod taxa, such as Malacostraca, some Chilopoda and also many Chelicerata, the vascular systems in particular are rather complex. Furthermore, a recent study has revealed that the prosomal ganglion of scorpions and spiders is supplied by an intricate network of arteries, the complexity of which bears a close resemblance to that of vertebrate capillary systems. In this study, we analyzed the hemolymph vascular systems of various species of Pedipalpi (i.e., Amblypygi and Uropygi). By combining modern techniques, such as MicroCT and cLSM, with computer-based 3D-reconstruction, we were able to produce comprehensive visualizations and descriptions of the vascular systems. Despite the lack of well-corroborated phylogenetic hypotheses on arachnid relationships and the controversial assertion of relationships between the pulmonate arachnids, we aim to elucidate the evolution of complex vascular systems in Arachnida. By comparing these highly complex vascular systems not only with each other, but also with other pulmonate arachnids, we found numerous detailed correspondences in the general branching pattern as well as in the supply patterns of the prosomal ganglion. We argue that these numerous and detailed correspondences by their absence in other arachnids i.e. aplumonates, support Arachnopulmonata. J. Morphol. 277:1084-1103, 2016. © 2016 Wiley Periodicals, Inc.


Subject(s)
Arachnida/anatomy & histology , Blood Vessels/anatomy & histology , Hemolymph/cytology , Animals , Arteries/anatomy & histology , Arteries/diagnostic imaging , Blood Vessels/diagnostic imaging , Heart/anatomy & histology , Heart/diagnostic imaging , X-Ray Microtomography
2.
Arthropod Struct Dev ; 41(6): 545-60, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22735399

ABSTRACT

Phylogenetically informative characters from the internal anatomy of scorpions were first reported more than 150 years ago, but the subject received little attention after the mid-1920s. Recent investigations, using traditional dissection, illustration and histological sectioning, microscopy, and innovative new methods for investigating complex soft tissue anatomy identified a new wealth of variation. Additionally, these investigations confirmed the phylogenetic significance of previously identified structures. Building on earlier work we present a more detailed description of the hemolymph vascular system (HVS) in scorpions, based on comparison of the vascular structures of the heart and the branching pattern of the prosomal arteries among 45 exemplar species representing most of the major scorpion lineages. Using corrosion-casting, MicroCT in combination with computer-aided 3D-reconstruction, and scanning electron microscopy, we conceptualize a series of phylogenetically informative characters for the anterior aorta system and characters of the heart and associated structures (e.g. arrangement of the ostia) of scorpions. Furthermore, we optimize the possible evolution of these new characters on a previous hypothesis of scorpion phylogeny, and discuss alternative character state transformations, their evolutionary consequences, and possible underlying evolutionary mechanisms acting on the HVS.


Subject(s)
Biological Evolution , Hemolymph/physiology , Scorpions/anatomy & histology , Scorpions/genetics , Animals , Computer Simulation , Female , Male , Models, Biological , Scorpions/classification , Scorpions/physiology
3.
J Chem Phys ; 128(12): 124316, 2008 Mar 28.
Article in English | MEDLINE | ID: mdl-18376928

ABSTRACT

Multiconfiguration Dirac-Fock method is employed to calculate the excitation energies, ionization potentials, oscillator strengths, and radii for all neutral and up to four times ionized species of element Uuq, as well as the homolog elements Ge, Sn, and Pb. Using an extrapolative scheme, improved ionization potentials of Uuq were obtained with an uncertainty of less than 2000 cm(-1). Two relatively stronger resonance transitions are predicted for the element Uuq. In particular, the strongest line in Uuq, corresponding to the [6d(10)7s(2)7p(3/2)8s(1/2)](1)-->[6d(10)7s(2)7p(3/2)(2)](2) transition at 22 343 cm(-1), just lies in the prime energy region of experimental measurement.

4.
J Chem Phys ; 127(13): 134310, 2007 Oct 07.
Article in English | MEDLINE | ID: mdl-17919027

ABSTRACT

Fully relativistic (four-component) density-functional theory calculations were performed for intermetallic dimers MM', where M=Ge, Sn, Pb, and element 114, and MM'=group 10 elements (Ni, Pd, and Pt) and group 11 elements (Cu, Ag, and Au). PbM and 114M, where M are group 14 elements, were also considered. The results have shown that trends in spectroscopic properties-atomization energies D(e), vibrational frequencies omega(e), and bond lengths R(e), as a function of MM', are similar for compounds of Ge, Sn, Pb, and element 114, except for D(e) of PbNi and 114Ni. They were shown to be determined by trends in the energies and space distribution of the valence ns(MM')atomic orbitals (AOs). According to the results, element 114 should form the weakest bonding with Ni and Ag, while the strongest with Pt due to the largest involvement of the 5d(Pt) AOs. In turn, trends in the spectroscopic properties of MM' as a function of M were shown to be determined by the behavior of the np(1/2)(M) AOs. Overall, D(e) of the element 114 dimers are about 1 eV smaller and R(e) are about 0.2 a.u. larger than those of the corresponding Pb compounds. Such a decrease in bonding of the element 114 dimers is caused by the large SO splitting of the 7p orbitals and a decreasing contribution of the relativistically stabilized 7p(1/2)(114) AO. On the basis of the calculated D(e) for the dimers, adsorption enthalpies of element 114 on the corresponding metal surfaces were estimated: They were shown to be about 100-150 kJ/mol smaller than those of Pb.

5.
J Chem Phys ; 126(17): 174702, 2007 May 07.
Article in English | MEDLINE | ID: mdl-17492874

ABSTRACT

Fully relativistic four-component density functional theory with the general gradient approximation calculations have been performed to determine the adsorption energy and position of the superheavy element 112 on a Au surface. Extended cluster as well as embedded cluster calculations were used to simulate the surface which allow for the top, bridge, and hollow adsorption sites without losing the advantage of symmetry considerations. Comparison with analogous calculations of the adsorption of the homologue element Hg allows to predict the adsorption of element 112 at a bridge site with a binding energy of 0.67 eV.

6.
Schmerz ; 21(3): 202-4, 206-11, 2007 Jun.
Article in German | MEDLINE | ID: mdl-17265015

ABSTRACT

BACKGROUND: Peculiarities of the hypothalamic-pituitary-adrenal axis activity in stress-related pain-disorders and potential relations with psychological risk factors of pain chronicity have been discussed controversially. MATERIAL AND METHODS: The cortisol awakening responses of 31 low back pain patients (14 acute, 17 chronic) and 14 healthy controls were compared. In addition the interrelations between awakening response and chronic stress as well as depressive mood and - for the first time - maladaptive painprocessing and -copingstrategies were investigated. RESULTS: The groups did not differ in their cortisol awakening responses. Chronic stress, depressive mood and maladaptive cognitive painprocessing did not correlate with the awakening response. There were, however, significant interrelations between awakening responses and the behavioral paincoping-strategies. CONCLUSIONS: Behavioral paincoping-strategies should be considered as a potentially important contributing psychological factor in the relation between the activity of the hypothalamic-pituitary-adrenal axis and stress-related pain disorders.


Subject(s)
Back Pain/physiopathology , Hydrocortisone/pharmacology , Wakefulness/drug effects , Acute Disease , Back Pain/psychology , Chronic Disease , Cognition Disorders/etiology , Depression/etiology , Humans , Psychological Tests
7.
Minim Invasive Neurosurg ; 48(2): 67-72, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15906199

ABSTRACT

A visual navigation system (VN) was developed which uses intraoperatively stored endoscopic images together with their specific 3D-address. A special calibration enables one to recalculate the distortion of the endoscopic images. Several modules (e. g., landmark tracking, virtual back-movement) are offered to the neurosurgeon. The system was tested in 12 human subjects during neuroendoscopic interventions and worked without problems in nearly all cases. The possibilities of digital image navigation can be used especially for control of instrument movement in case of red-out situations or blurred vision. Many further developments of the VN system are possible in order to increase the safety of neuroendoscopic interventions.


Subject(s)
Brain Diseases/surgery , Neuroendoscopy , Neuronavigation/instrumentation , Surgery, Computer-Assisted/instrumentation , Adolescent , Adult , Aged , Aged, 80 and over , Equipment Design , Equipment Failure , Female , Humans , Male , Middle Aged , Reproducibility of Results , Treatment Outcome
8.
J Chem Phys ; 122(12): 124301, 2005 Mar 22.
Article in English | MEDLINE | ID: mdl-15836372

ABSTRACT

The influence of relativistic effects on properties and volatility of the group-8 tetroxides MO4, where M=Ru, Os, and element 108, Hs, was studied on the basis of results of the fully relativistic (four component) and nonrelativistic density functional theory calculations. Relativistic effects were shown to increase bond strengths and decrease bond lengths in these molecules. They are responsible for a decrease in molecular polarizabilities and an increase in ionization potentials. The effects are much stronger in HsO4 than in the lighter congeners. Relativistic effects were also shown to slightly decrease dispersion interaction energies of RuO4, OsO4, and HsO4 with an inert (quartz or silicon nitride) surface, i.e., they increase volatility of these compounds as studied in the "one-atom-at-a-time" gas-phase chromatography experiments. They do, however, not influence the trend in group 8: both relativistically and nonrelativistically, volatility should change as RuO4

9.
Br J Neurosurg ; 19(5): 402-8, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16455561

ABSTRACT

During the development of new navigation systems, the ergonomic aspects of the accompanying software are seldom taken into account. The VN system is a navigation system working with real and previously stored neuroendoscopic images. The latter enable the module to execute virtual back movement, e.g. in case of bleeding. Several other modules are offered. The aim of the study was the ergonomic analysis of different modules and their learning curves in cadaveric heads. The endoscope was navigated by the neurosurgeon while another person operated the computer. A total of 128 experiments were performed with two software versions. When the landmark tracking module was used, a real learning curve could be observed. By contrast, testing the measurement module did not produce a learning curve. A significant reduction of the time required by the three modules investigated could be observed with software version 2. The module for virtual back movement works best with a minimum time of 20 s for image storage. During machine-human interactions ergonomic software use is important, especially if operative procedures are performed.


Subject(s)
Ergonomics/methods , Neuroendoscopy/methods , Neuronavigation/methods , Surgery, Computer-Assisted/methods , User-Computer Interface , Clinical Competence , Communication , Equipment Design , Humans , Interprofessional Relations , Neuroendoscopes , Neuronavigation/instrumentation , Software , Surgery, Computer-Assisted/instrumentation , Time Factors , Ventriculostomy/methods
10.
Minim Invasive Neurosurg ; 47(2): 79-85, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15257479

ABSTRACT

OBJECT: The aim of this study was to determine whether vibrography, an ultrasound-based real-time strain imaging method for registering the elastic properties of tissue, is superior to conventional ultrasound imaging techniques for detecting low-contrast space-occupying lesions in brain tissue and for delineating the boundaries between such lesions and the surrounding tissue. METHODS: As our experimental model we used swine brains taken from freshly slaughtered pigs. After injecting agarose into these brains at different depths, we compared both the conventional ultrasonographic images and the elastographic images of the region of interest with the corresponding anatomical brain sections. RESULTS: In 83.6 % of the experiments, it was possible to detect the polymerized agarose in the brain tissue with vibrographic techniques. In 17 experiments agarose lesions which were not detectable by ultrasound were visualized via vibrography. Furthermore, statistical analysis revealed that elastography is a more precise tool than conventional ultrasound for determining lesion size. CONCLUSION: These findings indicate that vibrography is a promising real-time imaging method with numerous potential applications in the field of neurosurgery. Visualization of the elastic properties provides the neurosurgeon with additional data on the lesion and the boundary between the lesion and the surrounding tissue.


Subject(s)
Echoencephalography/methods , Neuronavigation/methods , Ultrasonography, Interventional/methods , Vibration , Animals , Biomechanical Phenomena , Brain/pathology , Brain/surgery , Echoencephalography/veterinary , Swine , Tensile Strength
11.
Genet Res ; 83(2): 101-11, 2004 Apr.
Article in English | MEDLINE | ID: mdl-15219155

ABSTRACT

An understanding of genetic variation and structure of pest populations has the potential to improve the efficiency of measures to control them. Genetic analysis was undertaken at five microsatellite loci in four native Australian and 14 introduced New Zealand populations of the common brushtail possum Trichosurus vulpecula in order to document these parameters. Genetic variation in New Zealand populations, and phylogenetic relationships among Australian and New Zealand populations, were largely predicted by the recorded introduction history. Populations on the two main islands of New Zealand had only slightly lower genetic diversity than did Australian populations, except that allelic richness on the South Is. was significantly lower. Diversity was higher in North Is. than in South Is. populations (although not significantly so) and mainland New Zealand populations as a group were significantly more diverse than offshore islands that represented secondary population size bottlenecks. In phylogenetic analyses South Is. and offshore island populations grouped with Tasmania, while North Is. populations grouped either with mainland Australia or were intermediate between the two Australian sources. This scheme was supported by admixture coefficients showing that North and South Is./offshore island populations were largely mainland Australian and Tasmanian in origin, respectively. Population structure differed markedly between the North and South Islands: populations were typically more genetically differentiated on the former than the latter, which also showed significant isolation-by-distance. Substantial linkage disequilibrium in most sampled New Zealand but no Australian population between microsatellite loci Tv16 and Tv27 suggests they may be physically linked.


Subject(s)
Genetic Variation , Microsatellite Repeats , Opossums/genetics , Animals , Genetic Linkage , Linkage Disequilibrium , New Zealand , Phylogeny
12.
J Inherit Metab Dis ; 27(1): 29-46, 2004.
Article in English | MEDLINE | ID: mdl-14970744

ABSTRACT

The case of a French child, born of consanguineous parents of Tunisian origin, is described. He showed a severe multisystem disease with dyserythropoietic, sideroblastic anaemia, delayed neurological development with hypotonia and convulsions, salt-losing nephropathy, chronic watery diarrhoea, lactic acidosis with mitochondrial dysfunction, brittle hair, hypergammaglobulinaemia, fatty liver with intermittent transaminasaemia, and terminal pulmonary fibrosis. Two siblings, of both sexes, were stillborn; two more lived only a short time. One sister is alive and well. SDS gel analysis of the red cell membranes showed a deficiency within 'Band 7' at 32 kDa. Analysis of the gene encoding 'stomatin', or 'erythrocyte membrane protein 7.2b', the principal protein of 'Band 7', revealed a complex series of aberrant spliceforms centred around exon 3, for which no explanatory genomic lesion could be found. The true underlying molecular cause of this condition remains obscure, but it suggests that the stomatin gene should be studied in other cases.


Subject(s)
Alternative Splicing , Blood Proteins/deficiency , Blood Proteins/genetics , DNA, Recombinant , Genes, Recessive , Membrane Proteins/deficiency , Membrane Proteins/genetics , Metabolism, Inborn Errors/genetics , Blood Cells/pathology , Cerebral Ventricles/pathology , Child, Preschool , Fatal Outcome , Gene Amplification , Humans , Magnetic Resonance Imaging , Male , Metabolism, Inborn Errors/diagnosis , Pedigree , Radiography, Thoracic
13.
Nephron Physiol ; 93(2): p29-33, 2003.
Article in English | MEDLINE | ID: mdl-12629268

ABSTRACT

The human red cell has proved to be an invaluable model cell for the study of many aspects of membrane structure and function. It has a series of transport pathways which mediate the movements of the univalent cations Na and K, which are either identical or similar to systems in other human tissues, including the human kidney. The balance between the energy-consuming NaK pump and a 'passive leak' component maintains a net deficit of cations within the cell, which defends the cell volume against osmotic swelling. There exist a series of dominantly inherited human red cell conditions, gathered under the generic title 'hereditary stomatocytoses', in which the so-called 'passive leak' to Na and K is pathologically increased. In the more severe variants this compromises the integrity of the cell and the patients suffer haemolytic anaemia. Some less severe variants present with pseudohyperkalaemia caused by loss of K from red cells on storage of blood at room temperature. The most severe variants show a deficiency in a widely distributed 'raft' protein known as stomatin. The stomatin protein is homologous to the 'podocin' protein, the gene for which is mutated in a recessively inherited form of nephrotic syndrome. Among other possible functions, both proteins could be involved in the trafficking of membrane proteins to and from the plasma membrane.


Subject(s)
Anemia, Hemolytic, Congenital/genetics , Blood Proteins/genetics , Membrane Proteins , Nephrotic Syndrome/genetics , Blood Proteins/analysis , Blood Proteins/physiology , Erythrocyte Membrane/metabolism , Genome , Humans , Ion Transport , Kidney/chemistry , Mutation , Potassium , Sodium/metabolism , Temperature
14.
Phys Rev Lett ; 89(21): 213001, 2002 Nov 18.
Article in English | MEDLINE | ID: mdl-12443406

ABSTRACT

First full-relativistic density functional calculations with the extension of the spin-polarization functional for the relativistic density functional theory in their collinear and noncollinear form are presented here for the molecular system Pt2. The agreement with experiment is very good.

15.
Biochim Biophys Acta ; 1537(2): 132-46, 2001 Sep 28.
Article in English | MEDLINE | ID: mdl-11566257

ABSTRACT

A novel membrane proteinase of the nosocomial important bacteria species Bacillus cereus (synonyms: camelysin, CCMP) was purified up to homogeneity as was shown by mass spectrometry in its amphiphilic form. Camelysin is a neutral metalloprotease with a molecular mass of 19 kDa. Its unique N-terminus Phe-Phe-Ser-Asp-Lys-Glu-Val-Ser-Asn-Asn-Thr-Phe-Ala-Ala-Gly-Thr-Leu-Asp-Leu-Thr-Leu-Asn-Pro-Lys-Thr-Leu-Val-Asp-(Ile-Lys-Asp)- was not detected in the protein data bases during BLAST searches, but in the partially sequenced genome of Bacillus anthracis, coding for an unknown protein. Cleavage sites of the membrane proteinase for the insulin A- and B-chains were determined by mass spectrometry and N-terminal sequencing. Camelysin prefers cleavage sites in front of aliphatic and hydrophilic amino acid residues (-OH, -SO3H, amido group), avoiding bulky aromatic residues. The internally quenched fluorogenic substrates of the matrix metalloproteases 2 and 7 were cleaved with the highest efficiency at the Leu-decrease-Gly or Leu-decrease-Ala bond with the smaller residue in the P1' position. The protein specificity is broad--all various kinds of casein were cleaved as well as acid-soluble collagen, globin and ovalbumin; intact insulin was destroyed only to a low extent. Actin, collagen type I, fibrinogen, fibrin, alpha2-antiplasmin and alpha1-antitrypsin were cleaved. The protease formed SDS-stable complexes with Glu-plasminogen and antithrombin III, visible after SDS electrophoresis by gold staining and Western blot. The CCMP-plasminogen complex caused a partial activation of plasminogen to plasmin. Camelysin interacts with proteins of the blood coagulation cascade and could facilitate the penetration of fibrin clots and of the extracellular matrix during bacterial invasion.


Subject(s)
Bacillus cereus/enzymology , Bacterial Outer Membrane Proteins/metabolism , Metalloendopeptidases/metabolism , Amino Acid Sequence , Bacillus cereus/pathogenicity , Bacterial Outer Membrane Proteins/antagonists & inhibitors , Insulin/chemistry , Insulin/metabolism , Kinetics , Metalloendopeptidases/antagonists & inhibitors , Metalloendopeptidases/isolation & purification , Molecular Sequence Data , Peptide Fragments/chemistry , Plasminogen/metabolism , Polymers , Protease Inhibitors/pharmacology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Substrate Specificity
16.
Microsc Res Tech ; 53(2): 96-105, 2001 Apr 15.
Article in English | MEDLINE | ID: mdl-11301485

ABSTRACT

Pachymeninx and leptomeninx of cranial cavity and spine are considerably different in their collagenous fiber texture, cellular composition, vascularization, and innervation. The majority of meningeal nerve fibers terminate as free nerve endings whereas encapsulated and lamellated nerve terminals additionally occur in higher vertebrates including man. With respect to nerve fiber classification, arborization pattern, topography, and organization of the microenvironment at the termination site afferent and efferent nerve terminals are differentiated. Only the dura mater and the pial subcompartment of the leptomeninx possess the morphological prerequisites for neurogenic inflammation. In the current review, the results of morphological studies regarding the meningeal innervation including the sites of CSF (cerebrospinal fluid) production and absorption are discussed with emphasis on their structure-function relationships.


Subject(s)
Meninges/ultrastructure , Nerve Endings/ultrastructure , Nerve Fibers/ultrastructure , Skull/innervation , Spine/innervation , Arachnoid/ultrastructure , Cerebrospinal Fluid/metabolism , Dura Mater/ultrastructure , Humans , Meninges/anatomy & histology , Meninges/metabolism , Pia Mater/ultrastructure , Skull/anatomy & histology , Skull/ultrastructure , Spine/anatomy & histology , Spine/ultrastructure
17.
J Neurosurg ; 93(2): 342-50, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10930024

ABSTRACT

In this neuroendoscopic study the authors tested the newly developed "red-out module" of their visual navigation system that enables the neurosurgeon to achieve hemostasis if total visualization is lost due to hemorrhage ("red out") within the visual field. An optical position measurement system connected to the endoscope guarantees that digitized endoscopic images are coupled with the accurate endoscopic position. Computerized images are simultaneously stored with their respective position data, and this creates a virtual anatomical landscape. The system was tested in in vivo bleeding conditions in a rat model. Artificial endoscopic cavities were created in the inguinal, pelvic, and jugular regions in rats to imitate the conditions of the human ventricular system. Two experimental settings were tested: Technique I, in which a computer landmark has been previously determined at the point where the vessel will be lesioned; and Technique II, in which a landmark has been previously set in the surrounding area of the vessel. Immediately after hemorrhage obscures the visual field (red out), the computer automatically displays the virtual images on a separate monitor. The previously set landmarks and the graphic overlay of the coagulation fiber enable the surgeon to navigate within the operative field based on the virtual images and to perform coagulation at the site of the lesion. A total of 175 vessels were coagulated: 43 arteries and 132 veins. In using Technique I, 130 (90.9%) of 143 vessels and in using Technique II, 26 (81.2%) of 32 arteries were successfully coagulated. The authors' data revealed that virtual image guidance has the potential to be a helpful tool in neuroendoscopy.


Subject(s)
Endoscopy/methods , Image Processing, Computer-Assisted , Intracranial Hemorrhages/diagnostic imaging , Neurosurgical Procedures/methods , User-Computer Interface , Animals , Disease Models, Animal , Female , Hemostasis , Male , Radiography , Rats , Rats, Wistar
18.
Mol Ecol ; 9(7): 869-79, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10886650

ABSTRACT

We examined male reproductive success in a common brushtail possum population in New Zealand farmland. Paternity was assigned to 66 of 91 pouch young (maternity known), using a likelihood approach applied to genotypes at six microsatellite loci having an overall average exclusion probability of around 99%. The distribution of number of offspring per male was L-shaped with a standardized variance of 1.52. At least 46% of the 76 sampled reproductively mature males, bred, siring between one and four offspring each. Although breeding males were on average older and larger than nonbreeding males, the small differences did not result in a significant overall difference between the two groups in a multivariate permutation test analagous to a t-test. Paternity analysis of 22 sibling pairs (resulting from experimental removal of pouch young early in the breeding season, inducing a second oestrous) suggested that sequential mating of females with the same male was uncommon ( approximately 16-27%). Whilst there was a tendency for female possums to mate with nearby males, consistent with previous observations of territorial mating behaviour in Australian populations, some interhabitat matings were also inferred. The study population displayed only a low degree of polygyny, which may in part reflect population and habitat characteristics of the study site. A comprehensive understanding of the mating system of Trichosurus vulpecula awaits genetic paternity analysis in additional populations from both Australia and New Zealand, using quantitative approaches undertaken in this study.


Subject(s)
Animals, Wild/genetics , Opossums/genetics , Paternity , Sexual Behavior, Animal/physiology , Age Determination by Teeth , Alleles , Animals , Animals, Wild/physiology , Birth Rate , Female , Fertility , Male , Microsatellite Repeats/genetics , Multivariate Analysis , New Zealand , Opossums/physiology , Territoriality
19.
Anal Biochem ; 281(2): 144-50, 2000 Jun 01.
Article in English | MEDLINE | ID: mdl-10870829

ABSTRACT

Zwitterionic detergents interfere with the salt-induced phase separation for nonionic detergents in a concentration-dependent manner by shifting the normal cloud point of nonionic detergents to a higher ionic strength at room temperature. This phenomenon was used to determine the concentration of the zwitterionic detergents CHAPS, CHAPSO, and sulfobetaine SB-12 in solution by titration with ammonium sulfate in the presence of Triton X-100. Among the ionic detergents tested, the method was only applicable to sodium cholate. The assay can be used to control the removal of zwitterionic detergents during the reconstitution of membrane proteins in liposomes. However, it cannot be used to determine the specific binding of zwitterionic detergents to highly diluted, pure membrane proteins because of the limited sensitivity. Neither proteins nor phospholipids interfered with this method at concentrations up to 20 mg/ml of test solution (human serum albumin) or 10 mg/ml (phospholipids), respectively. Since the assay is based on the competition between salts and nonionic detergents for water molecules, it is important to equalize the ionic strength of samples and calibration standards.


Subject(s)
Cholic Acids/analysis , Detergents/analysis , Octoxynol/isolation & purification , Quaternary Ammonium Compounds/analysis , Sodium Cholate/chemistry , Cholic Acids/chemistry , Detergents/chemistry , Humans , Ion Exchange Resins/chemistry , Membrane Proteins/chemistry , Phospholipids/chemistry , Protein Binding , Quaternary Ammonium Compounds/chemistry
20.
Cell Tissue Res ; 299(3): 327-34, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10772247

ABSTRACT

Caenorhabditis elegans MEC-4 and MEC-10 are subunits of the degenerin/epithelial Na+ channel (DEG/ENaC) ion channel superfamily thought to be associated with MEC-2 (a stomatin-like protein) in a mechanotransducing molecular complex in specialized touch sensory neurons. A key question is whether analogous molecular complexes in higher organisms transduce mechanical signals. To address this question, we selected mechanoreceptors of the rat vibrissal follicle-sinus complex in the mystacial pad and the trigeminal ganglia for an immunocytochemical and molecular biological study. RT-PCR of poly(A+) mRNA of rat trigeminal ganglia indicated that alpha-, beta-, and gamma-ENaC and stomatin mRNA are expressed in rat trigeminal ganglia. Using immunocytochemistry, we found that alpha-, beta-, and gamma-ENaC subunits and stomatin are localized in the perikarya of the trigeminal neurons and in a minor fraction of their termination site in the vibrissal follicle-sinus complex, where longitudinal lanceolate endings are immunopositive. We conclude that alpha-, beta-, and gamma-ENaC subunits as well as the candidate interacting protein stomatin are coexpressed in a mammalian mechanoreceptor, a location consistent with a possible role in mechanotransduction.


Subject(s)
Blood Proteins/analysis , Neurons, Afferent/chemistry , Sodium Channels/analysis , Trigeminal Nerve/cytology , Animals , Antibodies , Blood Proteins/genetics , Blood Proteins/immunology , Epithelial Cells/chemistry , Epithelial Sodium Channels , Gene Expression/physiology , Immunohistochemistry , Mechanoreceptors/chemistry , Nerve Fibers, Myelinated/chemistry , Neurons, Afferent/ultrastructure , RNA, Messenger/analysis , Rats , Rats, Wistar , Signal Transduction/physiology , Sodium Channels/genetics , Sodium Channels/immunology , Vibrissae/innervation
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