Sex estimation using the first cervical vertebra

The articular surfaces and vertebral foramen area of the first cervical vertebra are sexually dimorphic and can be used to sex complete or fragmentary specimens. Eight measurements were taken from the articular regions (superior and inferior) of 100 first cervical vertebrae from Terry collection specimens housed at the Smithsonian Institution. Seven regression and seven discriminant function equations were created that predict sex with 77–85% and 75–85% accuracy, respectively. In separate control tests, measurements from 100 first cervical vertebrae from Hamann-Todd collection individuals (Cleveland Museum of Natural History) and from 34 archaeological specimens were used with the Terry equations. The control samples were sexed with 60—85% accuracy. © 1995 Wiley-Liss, Inc.     

Distribution and abundance of house-dust mites (Acarina: Pyroglycphidae) in Rome,Italy

For the first time in Rome, house-dust mite infestation was studied in 90 randomly selected houses. In each house, mite infestation was assessed in three sites: mattress, bedroom and living room. In total, 87.8% of the sampled houses were positive for dust mites. In the houses infested, 11.4% showed densities of >100 mites/g of dust, 15.2% registered densities between 50 and 99, and in the remaining houses (73.4%), the densities were between 1 and 49 mites/g dust. The percentages of infested houses were positively correlated with the relative humidity (RH) values (r=0.89,P=0.02). At the lowest range of RH (between 46 and 50), the infestation was 50% and at the highest range of RH (between 73 and 78) it was 100%. The mattress was significantly the most infested (71.1%) of the tested sites. Only wool and spring mattresses were infested, and they did not show any significant differences in mite concentrations.Dermatophagoides farinae was the most abundant species (53.1%), followed byGlycyphagus domesticus (34.5%),D. pteronyssinus (5.2%), andEuroglyphus maynei (0.2%);D. farinae was also the most frequent species (56.9%). The remaining specimens (7.0%) were predator species commonly found in houses. The prevalence ofD. farinae in Rome is discussed.     

Propylthiouracil Tasting: Determination of Underlying Threshold Distributions using Maximum Likelihood

The ability to taste low concentrations of propylthiouracil(PROP) and related bitter compounds is heritable. The currentanalysis determines whether the distribution of PROP taste thresholdsis consistent with an additive or a dominant mode of Mendeliantransmission. To that end, the lowest concentration of PROPdetectable was determined for 1015 subjects and models of bi-or tri-modal distributions of PROP taste thresholds were tested.The model with the greatest likelihood had three distributionsand followed an additive model of PROP taste sensitivity ifthe variances associated with the distributions were assumedto be equal. However, if the taste thresholds were transformedto remove skewness, or if the variances were unequal, then three-or two-distribution models were equally likely. Resolution ofthe mode of inheritance for bitter taste perception awaits additionalfamily studies and the characterization of the molecular basisof taste perception for these bitter compounds. Chem. Senses20: 529–533, 1995.     

Surfactant secretion in a newborn rabbit lung slice model

We describe a slice model for the study of pulmonary surfactant secretion in newborn rabbits. Full term rabbits were delivered by cesarean section and injected intraperitoneally with [Me-3H]choline. Four hours later they were killed, the lungs were perfused to remove blood, slices (0.5 mm thick) were prepared and incubated in buffer at 37 degrees C. The composition of the lipids initially released into the medium resembled those of lung tissue rather than surfactant. Following 3 changes of medium, however, the composition of the lipids released was very similar to that of lung lavage. Phosphatidylcholine accounted for over 70% of the total while phosphatidylethanolamine and sphingomyelin accounted for only 7% and 4%, respectively. 52% of the phosphatidylcholine was disaturated. Less than 5% of the tissue lactate dehydrogenase was released into the medium. The rate of phosphatidyl[Me-3H]choline release during this period was, therefore, measured. Release of phosphatidyl[Me-3H]choline was linear with time and was temperature-dependent. Prostaglandin E2 stimulated its rate of release by 20% while indomethacin and flufenamic acid, inhibitors of prostaglandin synthesis, inhibited it by 52% and 37%, respectively. The calcium ionophore A23187 in the presence of Ca2+ stimulated release by 40% while colchicine an cytochalasin B inhibited it by 36% and 32%, respectively. These data suggest that both prostaglandins and Ca2+ are involved in surfactant release and that intact microtubular and microfilament systems may also be necessary.     

Reactivity of sulphydryl groups of cytosolic and mitochondrial bovine aspartate aminotransferases

Summary Reactivity of sulphydryl groups of cytosolic and mitochondrial aspartate aminotransferases from ox heart has been studied. A total of 5 and 7 cysteine residues per monomer are present in cAATo and mAATo, respectively. In native conditions only a single sulphydryl group can be titrated by Nbs₂ while the catalytic activity remains unchanged, however in the mitochondrial isozyme the reactivity depends on the functional state of the enzyme. Reactivity toward NEM reveals the existence of a syncatalytic sulphydryl group in the cytosolic isozyme. Titration of cAATo with pMB at pH 8 and pH 5 confirms the existence of two exposed sulphydryl groups with a different reactivity. The results compared with those reported on the corresponding isozymes from pig and chicken heart show that syncatalytic sulphydryl groups are of general occurrence in these enzymes.     

Structural and functional analysis of the human neutrophil 1-15 antigen, an Mr 65,000 to 70,000 activation-associated membrane proteinase

Previous studies with the anti-neutrophil/antichymotrypsin mAb 1-15 have identified an activation-associated, chymotrypsin-like activity within the membrane fraction of isolated human neutrophils (PMN). In the present study, the molecular and biochemical characteristics of mAb 1-15 Ag/proteinase were determined. On casein/acrylamide sizing gels, PMN membrane preparations were found to contain an Mr 58,000 to 84,000 band of Ca2(+)-dependent proteinase activity. Reducing and nonreducing SDS-PAGE of mAb 1-15-affinity-purified membrane proteins demonstrated specific recovery of an enzymatically active Mr 65,000 to 70,000 chymotrypsin-like Ag. The presence of a distinct membrane serine esterase of isoelectric point 6.3/Mr 65,000 to 70,000 was confirmed in active site-labeling experiments with the serine proteinase inhibitor [3H]diisopropylfluorophosphate (DFP). Substrate-affinity chromatography with phe-Sepharose or FMLP-Sepharose provided partial purification of enzyme activity among Mr 65,000 to 70,000 FMLP- or phe-binding proteins. Enzyme inhibition was obtained by incubation with mAb 1-15, DFP, N-carbobenzoxyl-phe-chlormethyl ketone, or PMSF, but not tosyl-amide-phenylethylchlormethyl ketone, bestatin, aprotinin, or phosphoramidon. In HPLC analysis, [3H]DFP labeled proteinase was found to comigrate with one of three FMLP-affinity-labeled membrane peaks, but unlike the FMLP surface receptor the DFP-labeling membrane proteinase was not modified by endoglycosidase F. We conclude that the mAb 1-15 Ag, which appears to play a role in PMN activation, is a distinct, active, Mr 65,000 to 70,000 serine proteinase with affinity for substrate sites containing aromatic amino acids.     

A review of some physiological and evolutionary aspects of body size and bud size of Hydra

Green hydra with endosymbionts are smaller than brown asymbiotic ones. Regeneration experiments, mitotic index studies on algal and hydra tissue, and evidence for consumption and expulsion of algae are reviewed and it is suggested that larger green hydra have more difficulty controlling algal increase than smaller ones and that hydra have an upper size limit for maintenance of stable symbioses. A mathematical model is discussed which starts with simple physiological assumptions about hydra and generates field testable conclusions about how body and bud size, and reproductive rates depend on food particle size, quantity and temporal distribution. Unlike most analytic ecological-evolutionary models, this one integrates physiology, ecology and evolution without needing simplifying assumptions.     

Limited proteolysis as a probe of conformational changes in aspartate aminotransferase from Sulfolobus solfataricus.

The analysis of conformational transitions using limited proteolysis was carried out on a hyperthermophilic aspartate aminotransferase isolated from the archaebacterium Sulfolobus solfataricus, in comparison with pig cytosolic aspartate aminotransferase, a thoroughly studied mesophilic aminotransferase which shares about 15% similarity with the archaebacterial protein. Aspartate aminotransferase from S. solfataricus is cleaved at residue 28 by thermolysin and residues 32 and 33 by trypsin; analogously, pig heart cytosolic aspartate aminotransferase is cleaved at residues 19 and 25 [Iriarte, A., Hubert, E., Kraft, K. & Martinez-Carrion, M. (1984) J. Biol. Chem. 259, 723-728] by trypsin. In the case of aspartate aminotransferase from S. solfataricus, proteolytic cleavages also result in transaminase inactivation thus indicating that both enzymes, although evolutionarily distinct, possess a region involved in catalysis and well exposed to proteases which is similarly positioned in their primary structure. It has been reported that the binding of substrates induces a conformational transition in aspartate aminotransferases and protects the enzymes against proteolysis [Gehring, H. (1985) in Transaminases (Christen, P. & Metzler, D. E., eds) pp. 323-326, John Wiley & Sons, New York]. Aspartate aminotransferase from S. solfataricus is protected against proteolysis by substrates, but only at high temperatures (greater than 60 degrees C). To explain this behaviour, the kinetics of inactivation caused by thermolysin were measured in the temperature range 25-75 degrees C. The Arrhenius plot of the proteolytic kinetic constants measured in the absence of substrates is not rectilinear, while the same plot of the constants measured in the presence of substrates is a straight line. Limited proteolysis experiments suggest that aspartate aminotransferase from S. solfataricus undergoes a conformational transition induced by the binding of substrates. Another conformational transition which depends on temperature and occurs in the absence of substrates could explain the non-linear Arrhenius plot of the proteolytic kinetic constants. The latter conformational transition might also be related to the functioning of the archaebacterial aminotransferase since the Arrhenius plot of kcat is non-linear as well.     

Human alpha-fetoprotein primary structure: a mass spectrometric study.

The amino acid sequence of human alpha-fetoprotein, a 67-kDa protein present in mammalian embryonic serum, was verified by fast atom bombardment mass spectrometric (FAB/MS) analyses of three different enzymatic digests of the protein. Human alpha-fetoprotein obtained from a large-scale cell culture was digested with trypsin and V-8 protease either separately on two different samples or combined on the same one. The V-8 protease digest of the protein was partially fractionated by HPLC; the other samples were directly analyzed by FAB/MS without previous purification steps. About 90% of the alpha-fetoprotein amino acid sequence was verified by mass spectrometric analysis; this also confirmed that the cell-derived protein is identical with the hepatoma-derived protein. FAB analysis revealed that the N terminus of the mature protein is arginine rather than threonine, with the threonine occupying the second position. Therefore, the processing site of the alpha-fetoprotein signal peptide during maturation of the protein occurs at the N-terminal side of the arginine residue formerly indicated as residue-1. Thus mature alpha-fetoprotein contains 591 amino acids rather than 590.