Lek Social Organization and Reproductive Success in the Greater Prairie Chicken

Between 1964 and 1969, studies were made of Prairie Chickenreproductive behavior on a lek with a stable social organization.The social organization of this lek was altered by the removalof dominant males; three in 1970 and two in 1971. Social organizationand reproductive behavior were observed on this lek prior toand following removal of the dominant males. Removal of dominantmales disrupted the stable social organization on the lek. Totalnumber of aggressive interactions between males increased followingremoval of dominant males.No change was noted in the total numberof females visiting the lek in 1970 compared with the previous6-year period. Likewise, no change was noted in the number ofattempted copulations observed in 1970 compared with previousyears. However, the number of successful copulations was drasticallyreduced (90% fewer) during 1970 because of increased male-maleaggressive interactions on the lek. During 1971, fewer territorialmales were on the lek compared to previous years, and fewerfemales visited the lek and fewer successful copulations wererecorded than in previous years.Late nests of Prairie Chickensare less successful and contain fewer eggs compared with nestsbegun earlier. In some instances, the female social hierarchymay serve to delay onset of nesting, therefore reducing totalreproduction for the year.     

Fine Structure and Life Cycle of Lankesteria clarki sp. n. (Sporozoa: Eugregarinida) Parasitic in the Mosquito Aedes sierrensis (Ludlow)

Lankesteria clarki sp. n. from the treehole mosquito, Aedes sierrensis (Ludlow) in California, is described. This species can be separated from the closely related ones, L. culicis (Ross) and L. barretti Vávra, by the totally intracellular nature of the trophozoite, the shape of the gamont, the position of the gamont nucleus and the structure and position of the residual body in the spore. Morphologic and ultrastructural investigations of gametogenesis and sporogony were conducted and the host relationship discussed. Lankesteria clarki was found in mosquitoes collected from all treeholes examined near Novato in Marin County, California and an examination of over 6,000 larvae of A. sierrensis showed an infection rate of 27.5%. The parasite is capable of destroying the midgut epithelial cells during its trophic stage and Malpighian tubule cells during gametogenesis and sporogony.     

Insect Neuromuscular Synapses

Miniature end-plate potentials were used in studying severalaspects of the neuromuscular systems in the cockroach femur.The similar sizes and time courses of miniatures associatedwith fast and slow type excitatory axons suggest that they employthe same transmitter. There is other evidence also indicatingthat the essential difference between these two excitatory systemsis in the number of packets of transmitter released per nerveimpulse rather than different transmitter substances. From theshapes of miniatures it was suspected that typical muscle fibersmight have a branching structure. This was confirmed by histologicalexamination, intracellular stimulation, and intracellular dyeinjection. That inhibitory transmission is quantal is indicatedby hyperpolarizing miniatures which occur at random time intervals.Inhibitory transmission can be made to fail and recover in astepwise manner by manipulating the Ca/Mg ratio. In studiesof toxins which affect transmitter release at vertebrate motorend-plates, botulinal toxin was found to be without effect ateither excitatory or inhibitory junctions in cockroach muscle.However, black widow spider venom acted as it does in vertebrates,promoting massive release of transmitters and then permanentinactivation of the junctions.     

Metaphors of Hierarchy in a Mayan Ritual

Conventional actions denoting differences in rank are considered a central part of a Mayan ritual honoring a local saint and provide the basis for the formal analysis presented here. The ritual elements—acts drawn from daily etiquette and other ritual contexts—are combined in a way consistent with classic theories of ritual. While providing the basis for a formal argument, ways of designating rank order are not treated as "empty ritual": they pose a moral problem for the participants that contributes to the meaning of the ritual itself.     

A study of the heterogenous structure of guinea pig lysosomal beta-mannosidase using a polyclonal antibody

Lysosomal beta-mannosidase (EC 3.2.11.25) has a functional size of 120-150 kDa, but the enzyme purified from guinea pig liver (GPL) reportedly gave a single band corresponding to a molecular mass of 110 kDa. In order to investigate the subunit structure and tissue-specific expression of beta-mannosidase, we prepared a polyclonal antibody against GPL beta-mannosidase in rabbits which immunoprecipitated beta-mannosidase activity, free from other lysosomal hydrolase activity. Following storage at -20 degrees C and SDS polyacrylamide gel electrophoresis in the presence of 2-mercaptoethanol, a sample of purified GPL beta-mannosidase gave a major Coomassie blue staining band at 97 kDa. This was confirmed by Western blot analysis, which also revealed a faster moving 37 kDa protein. In contrast, Western blot analysis of fresh GPL homogenate prepared in the presence of proteinase inhibitors showed a major band at 150 kDa. Upon freezing and thawing, we observed immunoreactive bands at 120 and 20 kDa and finally, immunoreactive bands at 97, 37 and 20 kDa. The formation of the 97, 37 and 20 kDa forms from the 150 kDa species was accelerated by an n-butanol/ether extraction of the associated lipids, suggesting some tight hydrophobic association of these subunits. In contrast to liver, both fresh and freeze-thawed preparations of guinea pig kidney (GPK) yielded only the 97, 37 and 20 kDa subunit forms confirming that these are the major beta-mannosidase subunits. Endo-F treatment converted both the liver and kidney 97 kDa into a 91 kDa form and the 37 kDa form into a 35 kDa form, whereas the 20 kDa form was unaffected. Total beta-mannosidase activity, as measured with the synthetic substrate 4MU-beta-mannoside was unaffected by dissociation of the 150 form into the 97, 37 and 20 kDa subunits, suggesting that these are the functional forms of the enzyme rather than proteolytic degradation products.     

The human "peripheral-type" benzodiazepine receptor: regional mapping of the gene and characterization of the receptor expressed from cDNA.

A cDNA for the human "peripheral-type" benzodiazepine receptor (PBR) was isolated from a liver cDNA library. The 851-nucleotide probe hybridized with a approximately 1 kb mRNA in Northern blots of RNA extracted from various human tissues and cell lines. The human PBR probe was hybridized to DNA from a somatic cell hybrid mapping panel to determine that the gene maps to chromosome 22. With a regional mapping panel for chromosome 22, we localized the gene within band 22q13.31. The ligand-binding properties of the receptor expressed from the cDNA were examined in transient expression experiments and compared to the endogenous human PBR. The PBR ligand [3H]PK 11195 had high affinity for the expressed receptor in COS-1 cells, but the affinities of a pair of isoquinoline propanamide enantiomers differed remarkably in expressed and endogenous human PBR. These findings reveal that the host cell and/or post-translational modification may have an important influence on PBR function.     

Extinctions and migrations of Devonian rugose corals in the Eastern Americas Realm

Oliver, W. A., Jr. 1990 04 15: Extinctions and migrations of Devonian rugose corals in The Eastern Americas Realm. Lethaia , Vol. 23 , pp. 167–178. Oslo. ISSN 0024–1164.
Detailed plotting of the stratigraphic ranges of Devonian rugose coral genera within the Eastern Americas Realm reveals new information about the extinctions and migrations of this largely endemic fauna. There were significant faunal turnovers in the Lochkovian, middle Eifelian and late Givetian. as well as in the often discussed late Frasnian. The late Givetian turnover was nearly as great as the Frasnian one. Inward migration was principally from western North America, and the greatest influxes were during the carly Givetian and Frasnian. It seems likely that there were several separate incursions and that some genera were introduced to the east two, or even three times.     

Effects of dietary fish oil on plasma high density lipoprotein. Electron spin resonance and fluorescence polarization studies of lipid ordering and dynamics.

Dietary fish oils are implicated in reducing the incidence of coronary heart disease, perhaps by altering the properties of plasma lipoproteins. The hypothesis that omega-3 polyunsaturated fatty acids (PUFA) in fish oils produce changes in lipid ordering and dynamics within high density lipoprotein (HDL), thereby potentially modifying cholesterol transport, is investigated here. Rabbits were fed a diet supplemented with either 10% (by weight) menhaden oil (MO), a fish oil rich in omega-3 PUFAs, or hydrogenated cottonseed oil for a period of 12 weeks. HDL was isolated by sequential flotation ultracentrifugation from plasma drawn every 2 weeks. Gas chromatography confirmed that the predominant omega-3 PUFAs of fish oils, eicosapentaenoic 20:5 and docosahexaenoic 22:6 acids, were only incorporated into the triglyceride, phospholipid, and cholesteryl ester constituents of lipoproteins from rabbits on the MO diet. ESR of 5- and 16-doxyl stearic acids demonstrates that molecular order and dynamics within the outer monolayer of HDL is virtually unaffected. In contrast, ESR of cholesteryl 12-doxyl stearate indicates order is less within the inner apolar core of the lipoprotein for the MO diet than for the hydrogenated cottonseed oil diet. Fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene supports this finding. The greater disorder detected within HDL from rabbits fed fish oil may result in an enhancement of cholesterol exchange between lipoproteins and between lipoproteins and cells, which may have anti-atherogenic ramifications.     

Lead influences translational or posttranslational regulation of ia expression and increases invariant chain expression in mouse B cells

The molecular mechanisms governing the increased cell surface expression of major histocompatibility complex (MHC) class II molecules (Ia) on lead-treated mouse B cells was investigated. Lead has been shown to directly cause a selective, two-fold increase in the B cell's surface density of both products of the I region of the mouse MHC, I-A and I-E. In the present study, Western blot analysis showed that Pb increases the total cellular pool of I-A β-chain by twofold. The increase in cellular I-A was not found to be due to increased messenger RNA (mRNA) for either the α- or the β-chain of I-A. Biosynthetic labeling studies showed that Pb increases the translation or the stability of the Ia-associated invariant chain (Ii or γ) and possibly the β-chain of Ia. Collectively these results suggest that Pb increases the B cell's surface Ia by influencing translational or posttranslational regulation of Ia and/or Ia-associated chains.     

Carrier screening for phenylketonuria: comparison of two discriminant analysis procedures

Absence of a convenient, direct enzyme assay for detecting phenylketonuria (PKU) heterozygotes has resulted in continued effort to develop an accurate and reliable procedure to discriminate the heterozygous individual from the homozygous normal. Our study compares two statistical procedures that combine the semifasting plasma phenylalanine and tyrosine concentrations with the individuals' prior probability of being a heterozygous carrier in order to discriminate carriers from noncarriers. The results of this comparison indicate that the quadratic discriminant function is superior to the linear discriminant function as a method of carrier testing both in theory and in practice. An interactive computer system is described that facilitates the clinical utilization of the quadratic discriminant function.