Sequence analysis and comparison of avocado fruit and bean abscission cellulases

A 1700 nucleotide cDNA clone for a bean (Phaseolus vulgaris cv Red Kidney) abscission cellulase (endo-(1,4)-β-d-glucanase) has been identified and sequenced. This cDNA clone contains a 1485 nucleotide open reading frame which includes coding sequences for a putative signal peptide and mature protein. The nucleotide and deduced amino acid sequences for the bean abscission cellulase are compared to the previously reported sequences of an avocado fruit ripening cellulase. Optimal alignment of these sequences shows 64% and 50% identically matched nucleotides and amino acids, respectively. Analysis of the deduced amino acid sequences for the mature bean and avocado cellulases indicates that these two proteins share similar molecular weights, position of cysteine residues, and hydropathic character, but have very different isoelectric points and glycosylation. Genomic blot data suggest that the avocado fruit cellulase belongs to a small gene family, whereas the bean abscission cellulase appears to be encoded by a single gene or a few very closely related genes.     

The GTP-binding regulatory proteins of neuroblastoma x glioma, NG108-15, and glioma, C6, cells. Immunochemical evidence of a pertussis toxin substrate that is neither Ni nor No

Amounts of the guanine nucleotide binding regulatory proteins which are also pertussis toxin substrates (such as Ni and No) were measured in rat glioma, C6BU-1, cells and in neuroblastoma X glioma, NG108-15, hybrid cells. Measurements were performed both by quantitating pertussis toxin catalyzed ADP-ribosylation and by quantitative immunoblotting with affinity purified antibodies specific for Ni or No. The amounts of pertussis toxin substrate in C6 and NG108-15 cells are 7.5 and 0.6 pmol/mg membrane protein, respectively. These levels are minimum values and higher estimates of the total amounts of N proteins in the two cells are obtained by quantitative immunoblot analysis of the beta-subunit common to all N proteins. Immunoblots with specific antibodies show that NG108-15 cells contain 3.8 pmol/mg of No and detectable but small (less than 0.1 pmol/mg) amounts of Ni. In contrast, C6 cell membranes contain no detectable No and only 0.14 pmol/mg Ni. Thus, C6 cells contain large amounts of a pertussis toxin substrate which is neither Ni nor No.     

Extracellular and intracellular acid-base status following strenuous activity in the sea raven (Hemitripterus americanus)

Summary Exhausting activity in the sea raven resulted in a pronounced extracellular acidosis, which consisted of a large, short-lived respiratory component and a small, longer-lived metabolic component. Thi disturbance had been corrected by 12 h. White muscle experienced a pronounced intracellular acidosis of chiefly metabolic origin, with pH_i dropping from a resting value of 7.51 to a low of 7.10 immediately post-activity. The recovery of pH_i was associated with a reduction in muscle lactate. Despite the large increase in , cardiac muscle pH_i remained constant postactivity, actually showing an alkalosis at 30 min into recovery. Maintenance of cardiac muscle pH_i was achieved by an accumulation of HCO ₃ ^– intracellularly.     

The Intracellular Localization of Hormonal Activity in Transplantable Thyrotropin-Secreting Pituitary Tumors in Mice

Mouse pituitary tumors secreting almost exclusively thyroid stimulating hormone have been characterized electron microscopically. Tumors of known thyrotropin content were separated into nuclear, mitochondrial, microsomal, and soluble fractions by differential centrifugation. The hormonal activity of these fractions was correlated with that of the total homogenates and with their nitrogen and phosphorus content. Essentially all the thyrotropin of the homogenate was recovered in a particulate fraction sedimenting between 20,000 and 40,000 g. This fraction contained the RNA granules and membranous components typical of microsomal pellets, but also showed the presence of small dense bodies surrounded by smooth membranes. These bodies were also visible within the endoplasmic reticulum of intact cells, and it is postulated that these bodies may represent the sites of intracellular elaboration and/or storage of TSH. Thyrotropin is tightly associated with microsomal particles but can be brought into solution by treatment with alkaline media, deoxycholate, and certain organic solvents.     

Paleohistology of Paget's disease in two medieval skeletons.

Paget's disease has been ascribed several times to specimens of archeological bone but, in the absence of microscopic examination, the evidence remains insubstantial. Suspected metabolic bone disease is described here in the archeological remains of a skeleton from a 16th century burial ground at Wells Cathedral, England and from a single medieval sacrum recovered from a large deposit of disarticulated bones from a churchyard at Barton-on-Humber, England. Radiographs showed apparent structural abnormality in one femoral shaft and calcaneus and in the isolated sacrum. Histomorphometry on undecalcified bone cores confirmed the regions of abnormality and showed not only increased trabecular width but also areas of "mosaic" woven bone together with extensive resorption cavities; these features contrasted with the normal structure and organized lamellar bone from sites elsewhere. Despite post-interment changes in surrounding tissues, the morphological stability of some of the osteocytes was remarkable. Preservation of the histology was sufficient to permit the assignment of a metabolic bone disorder and the nature of the sclerosis was consistent with Paget's disease.     

Establishment of anaerobic,reducing conditions in lake sediment after deposition of acidic,aerobic sediment by a major storm

Hurricane Danny resulted in the rapid deposition of 10cm of oxidized, acidic sediment in the Contrary Creek arm of Lake Anna, Virginia. Several biological and geochemical parameters were monitored with time to ascertain how long it took the newly-deposited lake sediments to attain the anaerobic, circumneutral, actively sulfate-reducing state normally observed in this portion of the lake. The sediment platinum-electrode potential dropped from 350 mV to 100 mV within the first week after the storm. The pH of the pore water increased from 4.5 to 5.8 within three weeks, and titratable alkalinity was detected within two weeks and three weeks at 3 cm and 1 cm depths, respectively. Accumulation of reduced products of sulfate reduction (acid volatile sulfide) began by three to four weeks after the storm event. Both methanogens and sulfate reducers were present in high and approximately equal numbers in the freshly deposited material. The rapid neutralization of the acidity in the fresh sediment prior to the onset of sulfate reduction suggests that reactions other than sulfate reduction caused the initial increase in pH and alkalinity in this system.     

Genetic variation of recent Alu insertions in human populations

The Alu family of intersperesed repeats is comprised of ovr 500,000 members which may be divided into discrete subfamilies based upon mutations held in common between members. Distinct subfamilies of Alu sequences have amplified within the human genome in recent evolutionary history. Several individual Alu family members have amplified so recently in human evolution that they are variable as to presence and absence at specific loci within different human populations. Here, we report on the distribution of six polymorphic Alu insetions in a survey of 563 individuals from 14 human population groups across several continents. Our results indicate that these polymorphic Alu insertions probably have an African origin and that there is a much smaller amount of genetic variation between European populations than that found between other populations groups. Present address: Department of Pathology, Stanley S. Scott Cancer Center, Louisiana State University Medical Center, 1901 Perdido St., New Orleans, LA 70112 Correspondence to: M.A. Batzer     

An endochitinase gene expressed at high levels in the stylar transmitting tissue of tomatoes

A gene (pMON9617; Chi2;1) identified by screening a tomato pistil cDNA library has been found to encode a protein similar in sequence to class II chitinases. Using a baculovirus expression system we show that the Chi2;1 protein is an active endochitinase. The Chi2;1 protein is most similar in sequence to a previously described stylar chitinase (SK2) isolated from potato. Both proteins lack the diagnostic N-terminal cysteine-rich regions and the C-terminal vacuolar targeting signals of class I chitinases and appear to define a novel type of class II endochitinases associated with flowers. Chi2;1 is expressed predominantly in floral organs and its expression within these organs is temporally regulated. The highest level of expression is found in the transmitting tissue of the style where Chi2;1 mRNA begins to accumulate just prior to anthesis. In vegetative tissue, low levels of Chi2;1 mRNA were detected, and these levels did not increase in response to wounding or treatment with ethephon. mRNA from Chi2;1 orthologs was not detected in most other angiosperms tested, even including some members of the Solanaceae, and it is therefore unlikely that Chi2;1 is essential for stylar function. A fragment containing 1.4 kilobase pairs of 5-flanking DNA from the Chi2;1 gene was shown to drive high-level expression of an attached reporter gene in the styles of transgenic tomatoes. This fragment has utility for engineering expression of other coding regions in styles.     

The nervous system of Tricladida. I. Neuroanatomy ofProcerodes littoralis (Maricola,Procerodidae): An immunocytochemical study

The organization of the nervous system ofProcerodes littoralis (Tricladida, Maricola, Procerodidae) was studied by immunocytochemistry, using antibodies to authentic flatworm neuropeptide F (NPF) (Moniezia expansa). Compared to earlier investigations of the neuroanatomy of tricladid flatworms, the pattern of NPF immunoreactivity inProcerodes littoralis reveals differences in the following respects: 1. Shape and structure of the brain. 2. Number and composition of longitudinal nerve cords. 3. Shape of branches of, and transverse connections between, main ventral nerve cords. 4. Composition of the pharyngeal nervous system. The rich innervation by NPF immunoreactive (IR) fibres and cells of the subepithelial muscle layer, the pharynx musculature and the musculature of the male copulatory apparatus indicates a neurotransmitter or neuromodulatory influence on muscular activity.