Ribosomal DNA spacer-length polymorphisms in barley: mendelian inheritance, chromosomal location, and population dynamics.

Spacer-length (sl) variation in ribosomal RNA gene clusters (rDNA) was surveyed in 502 individual barley plants, including samples from 50 accessions of cultivated barley, 25 accessions of its wild ancestor, and five generations of composite cross II (CCII), an experimental population of barley. In total, 17 rDNA sl phenotypes, made up of 15 different rDNA sl variants, were observed. The 15 rDNA sl variants comprise a complete ladder in which each variant differs in length from adjacent variants by approximately equal to 115 nucleotide pairs.

Inheritance of nitrite reductase and regulation of nitrate reductase, nitrite reductase, and glutamine synthetase isozymes.

Banding patterns of nitrate reductase (NR), nitrite reductase (NiR), and glutamine synthetase (GS) from leaves of diploid barley (Hordeum vulgare), tetraploid wheat (Triticum durum), hexaploid wheat (Triticum aestivum), and tetraploid wild oats (Avena barbata) were compared following starch gel electrophoresis. Two NR isozymes, which appeared to be under different regulatory control, were observed in each of the three species. The activity of the more slowly migrating nitrate reductase isozyme (NR1) was induced by NO3- in green seedlings and cycloheximide inhibited induction.

Mutation Rates for Enzyme and Morphological Loci in Barley ( HORDEUM VULGARE L.).

Spontaneous mutation rates were estimated by assaying 84,126 seedlings of a highly homozygous barley line (isogenic line 2025) for five enzyme loci. No mutants were observed in 841,260 allele replications. This result excludes, at probability level 0.

Encysted parasitic larvae in the mouth.

Oral appearances of intestinal parasitic disease are rare. One such appearance is the presence in oral tissues of encysted or encapsulated larvae of organisms from the classes Cestoidea and Nematoda. Cestode larvae form cyst-like lesions that are often clinically diagnosed as mucoceles.

Evolution of resistance to scald, powdery mildew, and net blotch in barley composite cross II populations.

Progenies of barley plants taken at random from generations F8, F13, F23, and F45 of Composite Cross II were tested for reaction to three barley pathogens, Helminthosporium teres, Erysiphe graminis, and Rhynchosporium secalis (four races). The frequency of families resistant to each of the three pathogens (excepting one race of R. secalis) increased from early to later generations.

Retinitis pigmentosa--an overview.

Retinitis pigmentosa is a retinal pigment dystrophy of multiple genetic inheritance patterns affecting approximately .5% of the world population. It may be recognized clinically by observing specific ophthalmoscopic changes, as well as through psychophysical and electrodiagnostic testing.

Unusual healing of a fracture of an atrophic mandible. Report of a case.

Fractures of an atrophic edentulous mandible may present a serious problem in oral surgical treatment. A case is described in which a traumatic mandibular fracture, initially treated by means of a Gunning type of splint, and a subsequent spontaneous fracture on the opposite side were treated without mechanical fixation.

The thyroglossal cyst.

The thyroglossal cyst is the most common nonodontogenic cyst in the neck. This cyst may also occur in the lingual or submental areas, though more rarely. Malignant changes have been described.

Evolution of resistance to Rhynchosporium secalis (Oud.) Davis in barley composite cross II.

Changes in resistance to scald disease which occurred in barley composite Cross II over 45 generations were analyzed genetically. This population, which was synthesized in 1929 by pooling equal numbers of f1 seeds from 378 pair wise crosses among 28 barley varieties, has subsequently been grown at Davis, California under standard agricultural conditions without conscious selection. Progenies derived from self-pollinated seeds from random plants taken from four generations (F8, F13, F23, and F45) were tested against four different races of scald (40, 61, 72, and 74), and rated as resistant, susceptible or segregating.

Excess mortality from traffic accidents among elderly pedestrians living in the inner city.

Age-specific death rates for pedestrian-car accidents among the populations living in four contiguous areas of a large city, one being the downtown area and the others gradually more removed from it, were compared. The rates are highest downtown and decrease progressively in the outlying areas, the absolute differences between areas being largest above age 65. These data suggest that pedestrian accident prevention efforts should take into account the specific needs of the elderly living in the inner city.

Estimation of outcrossing rates in Duglas-fir using isozyme markers.

Seeds produced under open-pollination were collected from eight natural stands and a plus-tree seed orchard of Douglas-fir. These seeds were germinated and both diploid embryos and haploid gametophytes were analyzed by starch-gel electrophoresis. Eleven variable loci were resolved for both kinds of tissue and used as genetic markers for estimating outcrossing rates.

Nasopalatine duct cyst. Review of the literature and report of 22 cases.

The nasopalatine duct cyst is the most common non-odontogenic cyst in the oral area. The literature is reviewed regarding terminology, epidemiology, etiology, radiology, microscopic findings and treatment of these cysts, and is followed by a discussion of the data of 22 patients. A correct diagnosis can only the made after proper clinical, radiographic and histopathologic examination.

Worldwide patterns of genetic variation among four esterase loci in Barley (Hordeum vulgare L.).

Electrophoretic assays of 1506 accessions of domestic (Hordeum vulgare L.) and wild (H. spontaneum Koch.

A multilocus estimator of mating system parameters in plant populations.

A multilocus method of estimating mating system parameters in populations is presented that recovers information from classification over multiple loci that single-locus estimators do not detect. It is shown that the multilocus estimator provides a standard of reference (null hypothesis) that can be useful in analyzing the effects of factors such as population heterogeneity and post-mating zygotic selection on the transmission of genetic information at the population level.

Mucosal antral cysts. Review of the literature and report of a radiographic survey.

The increased use of panoramic radiography in dental practice has brought about the coincidental detection of abnormalities in the maxillary sinus, especially cysts of the mucosal lining. In our material of 1,080 patients, an incidence of 8.7 percent was found.

Naso-palatine duct cyst.

If present, symptoms of naso-palatine duct cyst are swelling, mainly in the anterior part of the palate, sometimes associated with pain. The cyst can easily be seen on X-ray, especially on the occlusal view. Differential diagnostic problems are mainly limited to a dentigerous cyst of a mesiodens and to periapical lesions of the central incisors.