A 76-bp deletion in the Mip gene causes autosomal dominant cataract in Hfi mice.

Hfi is a dominant cataract mutation where heterozygotes show hydropic lens fibers and homozygotes show total lens opacity. The Hfi locus was mapped to the distal part of mouse chromosome 10 close to the major intrinsic protein (Mip), which is expressed only in cell membranes of lens fibers. Molecular analysis of Mip revealed a 76-bp deletion that resulted in exon 2 skipping in Mip mRNA. In Hfi/Hfi this deletion resulted in a complete absence of the wildtype Mip. In contrast, Hfi/+ animals had the same amount of wildtype Mip as +/+. Results from pulse-chase expression studies excluded hetero-oligomerization of wildtype and mutant Mip as a possible mechanism for cataract formation in the Hfi/+. We propose that the cataract phenotype in the Hfi heterozygote mutant is due to a detrimental gain of function by the mutant Mip resulting in either cytotoxicity or disruption in processing of other proteins important for the lens. Cataract formation in the Hfi/Hfi mouse is probably a combined result of both the complete loss of wildtype Mip and a gain of function of the mutant Mip.     

Identification and characterization of a prevacuolar compartment in stigmas of nicotiana alata

The stigmas of the ornamental tobacco plant Nicotiana alata accumulate large quantities of a series of 6-kD proteinase inhibitors (PIs) in the central vacuole that are derived from a 40-kD precursor protein, Na-PI. The sorting information that directs Na-PI to the vacuole is likely to reside in a C-terminal propeptide domain of 25 amino acids that forms an amphipathic alpha helix. Using cell fractionation techniques, we have examined transit of Na-PI through the endomembrane system and have identified a prevacuolar compartment that contains Na-PI with an intact targeting signal. In contrast, the targeting signal is not present on the predominant form of Na-PI in the vacuole. The prevacuolar compartment is marked by the presence of homologs of both the t-SNARE, PEP12p, and the putative vacuolar sorting receptor BP-80. Cross-linking and affinity precipitation studies revealed that Na-PI associates with BP-80 within this compartment, providing in vivo evidence for the function of BP-80 as a sorting receptor for a protein with a C-terminal vacuolar targeting signal.     

Structural origins of fibrin clot rheology

The origins of clot rheological behavior associated with network morphology and factor XIIIa-induced cross-linking were studied in fibrin clots. Network morphology was manipulated by varying the concentrations of fibrinogen, thrombin, and calcium ion, and cross-linking was controlled by a synthetic, active-center inhibitor of FXIIIa. Quantitative measurements of network features (fiber lengths, fiber diameters, and fiber and branching densities) were made by analyzing computerized three-dimensional models constructed from stereo pairs of scanning electron micrographs. Large fiber diameters and lengths were established only when branching was minimal, and increases in fiber length were generally associated with increases in fiber diameter. Junctions at which three fibers joined were the dominant branchpoint type. Viscoelastic properties of the clots were measured with a rheometer and were correlated with structural features of the networks. At constant fibrinogen but varying thrombin and calcium concentrations, maximal rigidities were established in samples (both cross-linked and noncross-linked) which displayed a balance between large fiber sizes and great branching. Clot rigidity was also enhanced by increasing fiber and branchpoint densities at greater fibrinogen concentrations. Network morphology is only minimally altered by the FXIIIa-catalyzed cross-linking reaction, which seems to augment clot rigidity most likely by the stiffening of existing fibers.     

Characterization of 13 newly isolated strains of anaerobic, cellulolytic, thermophilic bacteria

Characteristics of 13 newly isolated thermophilic, anaerobic, and cellulolytic strains were compared with previously described strains of Clostridium thermocellum: ATCC 27405 and JW20 (ATCC 31549). Colony morphology, antibiotic sensitivity, fermentation end-products, and cellulose degradation were documented. All 13 strains were sensitive to erythromycin (5 μg/ml) and chloramphenicol (25 μg/ml), and all strains but one were sensitive to kanamycin (20 μg/ml). Polymerase chain reaction (PCR) amplification using primers based on gene sequences from C. thermocellum ATCC 27405 was successful for all 13 strains in the case of the hydrogenase gene and 11 strains in the case of phosphotransacetylase/acetate kinase genes. Ten strains amplified a product of the expected size with primers developed to be specific for C. thermocellum 16SrRNA primers. Two of the 13 strains did not amplify any product with the PCR primers designed for the phosphotransacetylase/acetate kinase and 16SrRNA primers. A MboI-like GATC- recognizing restriction activity was present in all of the five strains examined. The results of this study have several positive implications with respect to future development of a transformation system for cellulolytic thermophiles. Journal of Industrial Microbiology & Biotechnology (2001) 27, 275–280. Received 12 September 2000/ Accepted in revised form 20 November 2000     

Comparative analysis of the role of beta-endorphin systems in the mechanisms of different types of analgesia

Repeated immunization of rats with beta-endorphin-bovine albumin conjugate (75:7.5 g) mixed with Freund's adjuvant (1:1) induced a significant decrease in beta-endorphin content in the pituitary body and hypothalamus. The immunized rats showed suppressed antinociceptive reaction to morphine (5 mg/kg, i.p.) and in unavoidable foot shock. Cold swimming stress did not influence the pain reactions, as compared to the control group. The results indicate that mechanisms of different types of analgesia involve selective neurochemical systems.     

Thermal activity of the isolated brain fragment

The paper deals with thermovisional studies of thermal activity of hippocampus transplants placed in the eye anterior chamber of the rat. The method permits investigation into the dynamics of temperature field in the nervous tissue directly. In the transplants with synchronous spontaneous activity of large neuron groups there were found zones of high thermoactivity with mean amplitude 0.1 degree C, as well as thermopassive zones with temperature variations not above 0.03 degree C. Under certain conditions transfer of heat-up regions along the transplant surface, synchronous thermoactivation of single zones and chaotic regime of thermoactivation were observed. Causes of the observed effects are analysed. The method applied opens a new approach to the studies of space and time organization of the nervous tissue functioning in the course of its living activity.     

Identification of specific vasopressin binding sites in cell membranes of the adenohypophysis, liver, kidney and adrenal glands of the rat

3H vasopressin specifically binds to the binding sites in liver, kidney and adenohypophysis with Bmax = 11.8 +/- 5.6, 1.7 +/- 0.5 and 4.9 +/- 1.2 pmol/g tissue and Kd = 1.5 +/- 0.5, 0.66 +/- 0.21 and 0.84 +/- 0.21 nM, correspondingly. Specific binding increases in the presence of Mg2+ and Ni2+ and decreases at high temperature (37 degrees). The presence of high affinity binding sites for 3H vasopressin was shown in the rat adrenals, binding was saturable and reversible. Concentration of vasopressin binding sites in adrenals is 6-8 fold less than in adenohypophysis. It is supposed that vasopressin receptors in adrenals may participate in the regulation of corticosteroid secretion.     

Role of the locus coeruleus in the mechanism of different types of analgesia

The activity of antinociceptive mechanisms during exposure to cold swim stress (CSS), inescapable foot shock (FS) and morphine administration (10 mg/kg) was studied in rats subjected to bilateral lesions of locus coeruleus (LC). It has been shown that under all types of stimulation the latent periods (LP) of nociceptive reactions of paw licking and tail flick were significantly increased, as compared to baseline level, thus suggesting suppression of the pain sensitivity. In rats subjected to CSS and morphine administration significantly shorter LP were revealed in the experimental group, compared to the control, which suggested partial inhibition of antinociceptive mechanisms activity after LC lesion. FS did not cause any differences in the experimental and control groups. It is concluded that LC lesions cannot completely inhibit the antinociceptive mechanisms activated by CSS and morphine injection. In FS monoamine mechanisms of LC do not seem to play an important role in the functioning of antinociceptive mechanisms.     

The role of catecholaminergic group-A5 neurons in analgesia induced by auricular electroacupuncture and in electrodermal pain stimulation

The activity of antinociceptive mechanisms of auricular electroacupuncture (AEA) and footshock (FS) was studied on rats with bilaterally lesioned group A5 neurones. It was shown that the activity of the antinociceptive mechanisms triggered in experimental rats as compared to control rats. The data reveal the involvement of A5-nuclei in the antinociceptive mechanisms of AEA and FS.