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Biomedical subjects

S Brenner

Publications and source records attributed to S Brenner.

At least 361 records · Page 20Linked to original sources
PubMed1983

Protein structural domains in the Caenorhabditis elegans unc-54 myosin heavy chain gene are not separated by introns.

The 1,966-amino acid unc-54 myosin heavy chain sequence was determined from DNA sequence studies of the cloned gene. The gene is split by eight short introns, 48-561 base pairs long, and appears to lack a "TATA" box at its promoter. The physical map of the gene was aligned with the genetic map by locating two point mutations and three internal deletions: 0.01 map units correspond to approximately 5 kilobases. Comparison of the unc-54 protein sequence with the sequence of a second myosin heavy chain from nematode, indicates that the globular head sequence S-1 is more highly conserved than the alpha-helical coiled-coil rod. Major sites of proteolysis in S-1 are associated with variable sequences that have the characteristics of surface loops. In both genes there is no correlation between the positions of introns and the major protein structural domains.

Adenosine Triphosphate↗
PubMed1983

Taxol-requiring mutant of Chinese hamster ovary cells with impaired mitotic spindle assembly.

In the accompanying paper (Cabral, F., 1982, J. Cell. Biol., 97:22-29) we described the isolation and properties of taxol-requiring mutants of Chinese hamster ovary cells. We now show that at least one of these mutants, Tax-18, has an impaired ability to form a spindle apparatus. Immunofluorescence studies using antibodies to tubulin demonstrate that, when incubated in the absence of taxol, Tax-18 forms only a rudimentary spindle with few and shortened microtubules associated with the spindle poles. Furthermore, midbodies were not observed, consistent with an absence of cytokinesis. Essentially normal spindles and midbodies are seen in the presence of taxol. Electron microscopic examination indicates that centrioles and kinetochores are morphologically normal in the mutant strain. Pole-to-kinetochore microtubules were seen but interpolar microtubules were not. Taxol-deprived mutant cells stained with anti-centrosome serum show an elevated centriole content, indicating that the defect in Tax-18 does not affect centriole replication or prevent progression through the cell cycle. Although Tax-18 cells do not form a complete spindle in the absence of taxol, cytoplasmic microtubule assembly occurs in association with microtubule-organizing centers, and microtubules with apparently normal morphology exist throughout the cytoplasm. Observation of chromosome movement indicates that the defect in these cells occurs after prometaphase. These studies demonstrate that the formation of spindle microtubules requires cellular conditions that are different from those required for cytoplasmic microtubule formation. They further show that a normal spindle may be necessary for cytokinesis but not for progress of the cells through the cell cycle.

Alkaloids↗
PubMed1983

Factors that determine connectivity in the nervous system of Caenorhabditis elegans.

The nervous system of C. elegans is arranged as a collection of process bundles. Processes within bundles are generally unbranched and occupy defined positions relative to their neighbors. Small groups of processes are often closely associated together and run adjacent to one another for relatively long distances. We have defined the set of neurons that have processes adjacent to the processes of a given neuron as the neighborhood of that neuron. Synapses in C. elegans are made en passant between adjacent processes. Of the 1165 pairs of adjacent processes that were analyzed, 520 (45%) had synaptic contacts. The set of neurons that make synaptic contact with a given neuron is therefore, on average, 45% of that neuron's neighborhood. Neurons make synaptic contacts with fewer classes of partners than they have the potential for, as they are limited in their choice of partner to those that inhabit their neighborhood. Some classes of neurons have processes that make abrupt transitions from one neighborhood to another. There is usually some identifiable cue at the transition point, such as the termination of a closely associated process or a discontinuity at the junction of one process bundle with another. Neurons that inhabit more than one neighborhood have a more extended set of synaptic partners than those that are confined to a single neighborhood.

Animals↗
PubMed1983

Alkaline phosphatase immuno-enzymatic technique in the diagnosis of pemphigus vulgaris.

Alkaline phosphatase was used in an immuno-enzymatic procedure to detect tissue-bound and circulating antibodies in pemphigus vulgaris. Pemphigus antibodies were revealed by a direct method using alkaline phosphatase conjugated goat anti-human IgG. Cryostat sections were incubated with the specific antiserum, and alkaline phosphatase activity was then revealed histochemically either by Gomori's technique or by the azo dye method. The sections were examined by light microscopy and intercellular staining was demonstrated in the epidermis. The indirect method, in which the patient's serum was incubated with sections of normal skin, gave similar results. Using parallel sections, an immunofluorescent technique was used to demonstrate tissue-bound and circulating antibodies. The alkaline phosphatase method appeared to be slightly less sensitive than the immunofluorescent method.

Alkaline Phosphatase↗
PubMed1983

Perforating cutaneous mucinosis.

A case is described in which a papulonodular eruption developed all over the body. Histologic examination of one of the lesions revealed the dermis to contain mucin (hyaluronic acid). In some areas there was perforation through the epidermis of the mucinous material.

Adult↗
PubMed1983

An unusual pattern of arthritis dermatitis syndrome.

A 27-year-old woman presented with skin lesions and arthritis of the right knee of two days' duration. Her medical history was noncontributory and synovial fluid aspirated from the affected knee and a biopsy of a skin lesion were negative for gonococci. However, after methylene blue staining of cervical and urethral smears, intracellular and extracellular diplococci were demonstrated. Immunofluorescence showed deposits of immunoglobulin complexes of the skin section within the wall of blood vessels and dermal-epidermal junction. Treatment with ampicillin, 4 gm a day, resulted in resolution of the lesions and arthritis in two days. The need for cervical and urethral smears and for better, as yet unavailable tools for the diagnosis of the arthritis dermatitis syndrome, is emphasized.

Adult↗
PubMed1983

Angioimmunoblastic lymphadenopathy with scleromyxedema-like lesions and serum monoclonal protein.

A patient was followed up for 5 yr for an illness diagnosed histologically as angioimmunoblastic lymphadenopathy. His serum contained a monoclonal protein of the IgM type, and biopsies from papular skin lesions revealed scleromyxedema-like features. The unusual association of this kind of cutaneous lesion with angioimmunoblastic lymphadenopathy and a monoclonal IgM is discussed.

Bone Marrow Examination↗
PubMed1982

Rat liver L-glutamate dehydrogenase, malate dehydrogenase, D-beta-hydroxybutyrate dehydrogenase, and sulfite oxidase are each synthesized as larger precursors by cytoplasmic free polysomes.

Four cytoplasmically synthesized rat liver mitochondrial enzymes, located either as soluble enzymes in the mitochondrial matrix (L-glutamate dehydrogenase and malate dehydrogenase or in the intermembrane space (sulfite oxidase) or as an integral membrane protein located on the matrix face of the inner mitochondrial membrane (D-beta-hydroxybutyrate dehydrogenase), were all shown to be synthesized as precursors larger than their mature counterparts by 1000-6000 daltons. These larger forms were detected in vitro, in a cell-free protein synthesizing system programmed with either total rat liver RNA or with RNA isolated from free polysomes or with free polysomes, and in vivo, in the two cases that were investigated (L-glutamate dehydrogenase and D-beta-hydroxybutyrate dehydrogenase), by pulse labeling of Buffalo rat liver cells in culture. The intracellular site of synthesis of all four mitochondrial enzymes was shown to be primarily on free polysomes and not on membrane-bound polysomes.

Animals↗
PubMed1982

Phasmids: hybrids between ColE1 plasmids and E. coli bacteriophage lambda.

Plasmids carrying cloned lambda att sites may be integrated into the bacteriophage genome by the site-specific recombination mechanism of lambda. The cross, referred to as "lifting" the plasmid, requires mixed infection of an Escherichia coli strain carrying the plasmid with two appropriately constructed "lifting" lambda phages. One phage donates a short left arm and the other donates a short right arm. These two short arms are of insufficient length to produce a viable phage genome and yield no recombinants when crossed on standard bacteria. However, viable recombinants are obtained when the genome length is extended by integration of one or more plasmids. We call these recombinants phasmids. They contain multiple att sites introduced at the ends of the integrated plasmids, and in the presence of integrase, recombination between these att sites can be exploited to effect release of the plasmid components. These novel genetic elements can be used in a variety of ways as vectors in genetic manipulation experiments. Sequences cloned in phasmids may be studied as a component of either a plasmid and or of a phage, and easily interconverted between the two states.

Attachment Sites, Microbiological↗
PubMed1982

Idiopathic lipogranulomatosis of spleen and periaortic lymph nodes with noncaseating granulomas of liver.

An unusual case of acute febrile illness clinically thought to be a manifestation of either granulomatous hepatitis or Hodgkin's disease is described. The spleen and enlarged periaortic lymph nodes at the level of the spleen revealed multiple noncaseating granulomas containing vacuoles and associated multinucleated giant cells. The lesions appeared to be consistent with lipogranulomas. The liver contained multiple noncaseating granulomas. The clinical history and analyses of tissue samples failed to document the presence of exogenous lipid. There was no evidence in support of a viral, fungal, or bacterial cause for any of the known granuloma-forming diseases. The patient recovered on steroid therapy and has remained well for one year following the onset of the acute illness. The possibility that this case represents lipogranulomatous pseudosarcoid of the spleen and periaortic lymph nodes or a variant of sarcoid cannot be excluded.

Aged↗