The structure and characterization of the surface protein layer of a Comamonas-like organism

The regular surface layer of a strain of a Comamonas-like organism was examined by electron microscopy. The surface layer protein was easily extracted from the cell surface by a 2.5 M solution of lithium chloride. The protein subunit has a molecular size of 32,000 daltons, but usually forms a large aggregate of more than 1,200,000 daltons. In the extract it formed a regular array of p4 symmetry and was observed to be intimately associated with fragments of lipopolysaccharide. The size of a subunit determined by the negative staining method and the image processing method measured 5.2 x 6.4 nm (width and length), was arranged in a cobblestone-like pattern, and was located in a lattice space measuring 13.0 nm square.     

The 1993 epidemic of dengue fever in Mangalore, Karnataka state, India

Distal spinal muscular atrophy is a rare lower motor neuron disorder that may be difficult to distinguish clinically from type II Charcot-Marie-Tooth disease. We report on clinical and pathologic findings in 13 members of a four-generation extended family with autosomal dominant distal spinal muscular atrophy. The patients developed a slowly progressive lower motor neuron disorder involving mainly the distal lower extremities; onset was from the second to fourth decades. Electromyography and muscle biopsy findings were indicative of motor denervation. Combined silver/cholinesterase/immunocytochemical staining of intramuscular nerve revealed abundant collateral axonal branching in mild disease but marked loss of terminal motor endplate innervation in the more severe state, suggesting decreased growth of motor axon collaterals with disease progression. Multipoint DNA linkage analysis showed that this family's disorder is not linked to the chromosome 5q11.2-13.3 spinal muscular atrophy locus.     

Cholinoreception in Ascaris suum (Nematoda) ascarids and the liver fluke Fasciola hepatica (Trematoda)

Homogenates of synaptically rich structures of the body (the anterior end of A. suum and F. hepatica, as well as narrow strips of the anterior part of A. suum with median nerves and innervation processes of muscle cells) have been tested for the presence of acetylcholine receptor protein (AchR). Strips of the A. suum muscle tissue with low content of synaptic structures served as a control. AchR was detected by the decrease in the optic density at 260 nm and by the decrease in the reactivity of AchR SH-groups in the presence of Ach. Using both methods, AchR was found in water-soluble fraction of tissue homogenates rich in synaptic structures. No AchR was detected in tissues which do not contain synpatic structures. The data obtained are discussed in relation to the function of Ach as a mediator in helminths.