Cementum annulation and age determination in Homo sapiens. II. Estimates and accuracy

The cementum annulation aging technique was evaluated in a sample of 80 clinically extracted premolars (age range 11–70 years). Demineralized thin sections (7μm) stained with hematoxylin were used. The correlation (r) between age and adjusted count (number of annulations added to age of tooth eruption) was 0.78 for the entire sample (N = 73) and 0.86 for a subsample in which teeth with periodontal disease were excluded (N = 55). Standard error of the estimates ranged from 4.7 to 9.7 years depending on sex and health status of the tooth. The technique provided significantly better estimates for females than for males. The overall inaccuracy (mean absolute error) of the technique was 6.0 years, with a bias (mean error) of 0.26 years. Reduced major axis regression of adjusted count on age produced a slope of 0.797 for the entire sample and 0.889 for the nonperiodontal disease subsample. These slopes are consistent with a hypothesis of annual deposition of cementum rings given a decrease in cementogenesis with increasing age.     

Localization of a highly immunogenic region on the acetylcholine receptor alpha-subunit

Antibodies to synthetic peptides were employed in order to map domains on the alpha-subunit of the acetylcholine receptor to which several monoclonal antibodies are directed. Five peptides corresponding to residues 1-20, 126-143, 169-181, 330-340 and 351-368 of the receptor alpha-subunit were synthesized and antibodies against them were elicited. The anti-peptide antibodies were employed along with the monoclonal antibodies to identify fragments of S. aureus V8 protease digested- alpha-subunit in immunoblotting experiments. Our results demonstrate that a highly immunogenic region of the alpha-subunit is located on a carboxy-terminal 14 kDa portion of the alpha-subunit. This region also seems to undergo antigenic changes during muscle development. A monoclonal antibody directed against the cholinergic binding site of the acetylcholine receptor reacted with an 18 kDa segment of the alpha-subunit which bound alpha-bungarotoxin as well as antibodies directed against peptide 169-181.     

A new Madia of sect. Anisocarpus (Compositae: Heliantheae) from Trinity County,California

A new annual species ofMadia sect.Anisocarpus,Madia doris-nilesiae, from the serpentine soils of western Trinity County, California is described, illustrated, and compared to the other annual members of the section. On the basis of floral and fruit morphologies the annual members of the section can be divided into two geographical units.Madia dorisnilesiae is unique in that it has a combination of these characters.     

Inoculation and production of container-grown red alder seedlings

Summary The inoculation ofAlnus rubra (red alder) withFrankia sp. can lead to a highly efficient symbiosis. Several factors contribute to the successful establishment of nitrogenfixing nodules: (1) quantity and quality ofFrankia inoculant; (2) time and method of inoculation; (3) nutritional status of the host plant.Frankia isolates were screened for their ability to nodulate and promote plant growth of container-grown red alder. Inoculations were performed on seedlings and seeds. Apparent differences in symbiotic performance could be seen when seeds or seedlings were inoculated. Plants inoculated at planting performed significantly better than those inoculated four weeks later in terms of shoot height, nodule number and shoot dry weight. If inoculation was delayed further, reduction in shoot height, nodule number and shoot dry weight resulted. The effect of fertilizer was also investigated with regard to providing optimal plant growth after inoculation. Plants receiving 1/5 Hoagland's solution minus nitrogen showed maximal plant growth with abundant nodulation. Plants receiving 1/5 Hoagland's solution with nitrogen showed excellent plant growth with significantly reduced nodulation.     

Immunoassay of the Neuronal and Neuroendocrine Marker PGP 9.5 in Human Tissues

An inhibitory, coated-well immunoassay for the neurone-specific protein PGP 9.5 has been devised and used to measure the concentrations of the protein in human tissues. Concentrations of PGP 9.5 between 40 ng/ml and 10 micrograms/ml could be measured using this assay. In brain PGP 9.5 was present at 100.58 +/- 16.18 micrograms/mg protein. Of the other organs examined only kidney and testis showed significant concentrations of PGP 9.5 (3.97 +/- 0.87 microgram/mg protein and 3.25 +/- 0.36 microgram/mg protein, respectively). All other organs contained less than 2% of the brain level. The tissue levels determined by coated-well immunoassay confirmed the tissue specificity of PGP 9.5 originally determined by high-resolution two-dimensional gel electrophoresis.     

The effect of glucose on cellobiose uptake and β-D-glucosidase activity inStreptomyces granaticolor

Glucose inhibits the inducible synthesis of β-D-glucosidase inStreptomyces granaticolor. Neither cAMP nor cGMP influence the inhibitory effect of glucose. Glucose also inhibits the inducible synthesis of the cellobiose uptake system but has no effect on its activity. This may be the mechanism underlying glucose inhibition of induction of β-D-glucosidase inS.granaticolor.     

Monoclonal antibodies to the two most basic papaya proteinases

The proteinases fromCarica papaya include papain, isoenzymes of chymopapain and two proteinases A and B distinguished by their unusually high pI. The identity of one of the most basic proteinases has been questioned. The present report describes the preparation and characterisation of two monoclonal antibodies that react specifically with papaya proteinases A and B respectively and a third that identifies a common structural feature found in papain and proteinase A.     

NMR, CD and IR spectroscopies of a tridecanucleotide containing a no-base residue: coexistence of B and Z conformations.

The synthesis of the tridecadeoxynucleotide d(CGm5CGCGxACATGT), where x is the 1-cyano-2-deoxy-beta-D-erythropentofuranose, is described. The NMR, IR, CD studies at various salt concentrations and temperatures of this oligomer show that the B and Z conformations are simultaneously present in the same short DNA fragment. A single apurinic residue is sufficient for the coexistence of the B and Z helices on this oligomer.     

Pattern formation in fragmented eggs of the short germ insect Schistocerca gregaria

Summary The effect of transverse fragmentation on the segment pattern of the short germ embryo of the locust Schistocerca gregaria has been investigated at two stages subsequent to the formation of the germ anlage. Following fragmentation both anterior and posterior partial embryos were observed, although rarely in a single egg. Anterior partial patterns usually terminated with a segment visible at the time of fragmentation or with the next segment due to appear. Posterior partial patterns began with a wide range of segments depending on the level of fragmentation.Anterior and posterior partial patterns developing in a single egg were usually not complementary and the segments missing sometimes included some segments visible when the embryo was fragmented. Non-complementary patterns resulted following fragmentation in all regions, while complementary patterns only occurred after fragmentation in the visibly-segmented region.The results suggest that following fragmentation isolated posterior portions of the embryo continue to form segments, while isolated anterior regions usually do not. This effect could result from variable damage to an existing pattern of unequally-sized segment primordia, or from the disruption of a process of sequential segmentation in the elongating posterior region of the embryo. The results are broadly compatible with the progress zone model proposed by Summerbell et al. (1973).