Relationship between sperm concentration and the incidence of polyspermy in mouse embryos fertilized in vitro

A dose-response relationship between the incidence of polyspermy and sperm concentration was found by analysing chromosome preparations of first-cleavage mouse embryos derived from fertilizations in vitro with 3 concentrations of mouse spermatozoa (2 x 10(4), 2 x 10(6) and 1 x 10(7)/ml).     

Adenovirus type 2 late mRNA's: structural evidence for 3'-coterminal species.

Adenovirus type 2-infected HeLa cells were labeled with 32PO4 during the period 14 to 17 h postinfection. Viral mRNA's with polyadenylic acid were isolated by polyuridylic acid Sepharose chromatography and fractionated according to size by electrophoresis through an acrylamide-agarose slab gel. Messenger bands were eluted and partially degraded with alkali. RNA fragments from each band that contain polyadenylic acid were isolated by polyuridylic acid Sepharose chromatography and fingerprinted two-dimensionally after T1 RNase digestion. Three bands, with mobilities of approximately 26S, 21S, and 18S, shared two large characteristic T1 oligonucleotides in common in the fingerprints of their 3'-terminal sequences. These oligonucleotides were mapped with a Hpa II restriction fragment of adenovirus type 2 DNA with coordinates 49-50.2. We conclude that the three mRNA's are coterminal in sequence at their 3' ends and overlap at internal positions. Implications for the protein-coding potential of these mRNA's and the mechanisms of adenovirus tyep 2 late RNA processing are discussed.     

Early adaptations in blood substrates, metabolites, and hormones to prolonged exercise training in man.

This study was designed to investigate the effect of short-term, submaximal training on changes in blood substrates, metabolites, and hormonal concentrations during prolonged exercise at the same power output. Cycle training was performed daily by eight male subjects (VO2max = 53.0 +/- 2.0 mL.kg-1.min-1, mean +/- SE) for 10-12 days with each exercise session lasting for 2 h at an average intensity of 59% of VO2max. This training protocol resulted in reductions (p less than 0.05) in blood lactate concentration (mM) at 15 min (2.96 +/- 0.46 vs. 1.73 +/- 0.23), 30 min (2.92 +/- 0.46 vs. 1.70 +/- 0.22), 60 min (2.96 +/- 0.53 vs. 1.72 +/- 0.29), and 90 min (2.58 +/- 1.3 vs. 1.62 +/- 0.23) of exercise. The reduction in blood lactate was also accompanied by lower (p less than 0.05) concentrations of both ammonia and uric acid. Similarly, following training lower concentrations (p less than 0.05) were observed for blood beta-hydroxybutyrate (60 and 90 min) and serum free fatty acids (90 min). Blood glucose (15 and 30 min) and blood glycerol (30 and 60 min) were higher (p less than 0.05) following training, whereas blood alanine and pyruvate were unaffected. For the hormones insulin, glucagon, epinephrine, and norepinephrine, only epinephrine and norepinephrine were altered with training. For both of the catecholamines, the exercise-induced increase was blunted (p less than 0.05) at both 60 and 90 min. As indicated by the changes in blood lactate, ammonia, and uric acid, a depression in glycolysis and IMP formation is suggested as an early adaptive response to prolonged submaximal exercise training.     

Uptake of hyaluronan in hepatic endothelial cells is not directly affected by endotoxin and associated cytokines

The uptake of hyaluronan (HYA) labeled with 3H in its acetyl group was measured in cultured liver endothelial cells from normal rats and from rats previously treated with sublethal doses of Escherichia coli endotoxin (ET). Replicate cultures were also exposed to recombinant human tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1) or interferon-gamma for 1 to 3 h before the measurement of hyaluronan uptake. Under all conditions, HYA was absorbed by endothelial cells at rates consistent with receptor-mediated absorption. In cells exposed to HYA 20 h after isolation, rate of uptake was less than half the rate in cells exposed 6 or 7 h after isolation. Cellular uptake of HYA was neither reduced nor enhanced by any of the treatments with cytokines. Prior exposure of the cell donors to ET caused a three-fold increase in their plasma HYA but did not alter the subsequent rate of cellular HYA uptake in vitro, either with or without added treatment with TNF-alpha or IL-1. It was concluded that the elevation of plasma HYA caused by septicaemia or by the experimental administration of ET or TNF-alpha cannot be attributed to direct interference with HYA receptors on hepatic endothelial cells.     

Phylogeny of Helicobacter felis sp. nov., Helicobacter mustelae, and related bacteria.

Strain CS1T (T = type strain) is a gram-negative, microaerophilic, urease-positive, spiral-shaped bacterium that was isolated from the gastric mucosa of a cat. Additional strains which possessed biochemical and ultrastructural characteristics similar to those of strain CS1T were isolated from the gastric mucosa of cats and dogs. The guanine-plus-cytosine content of the DNA of strain CS1T was 42.5 mol%. The 16S rRNA sequences of strain CS1T, strain DS3 (a spiral-shaped isolate from a dog), and Helicobacter mustelae were determined by direct RNA sequencing, using a modified Sanger method. These sequences were compared with the 16S rRNA sequences of Helicobacter pylori, "Flexispira rappini," Wolinella succinogenes, and 11 species of campylobacters. A dendrogram was constructed based upon sequence similarities. Strains CS1T and DS3 were very closely related (level of similarity, 99.3%). Two major phylogenetic groups were formed; one group consisted of strains CS1T and DS3, H. mustelae, H. pylori, "F. rappini," and W. succinogenes, and the other group contained the true campylobacters. The average level of similarity between members of these two groups was 84.9%. Within the first group, strains CS1T and DS3, H. pylori, and H. mustelae formed a cluster of organisms with an interspecies similarity level of 94.5%. The phylogenetic positions of W. succinogenes and "F. rappini" were just outside this cluster. On the basis of the results of this study, we believe that strains CS1T (= ATCC 49179T) and DS3 represent a new species of the genus Helicobacter, for which we propose the name Helicobacter felis.     

Phylogeny of 54 representative strains of species in the family Pasteurellaceae as determined by comparison of 16S rRNA sequences.

Virtually complete 16S rRNA sequences were determined for 54 representative strains of species in the family Pasteurellaceae. Of these strains, 15 were Pasteurella, 16 were Actinobacillus, and 23 were Haemophilus. A phylogenetic tree was constructed based on sequence similarity, using the Neighbor-Joining method. Fifty-three of the strains fell within four large clusters. The first cluster included the type strains of Haemophilus influenzae, H. aegyptius, H. aphrophilus, H. haemolyticus, H. paraphrophilus, H. segnis, and Actinobacillus actinomycetemcomitans. This cluster also contained A. actinomycetemcomitans FDC Y4, ATCC 29522, ATCC 29523, and ATCC 29524 and H. aphrophilus NCTC 7901. The second cluster included the type strains of A. seminis and Pasteurella aerogenes and H. somnus OVCG 43826. The third cluster was composed of the type strains of Pasteurella multocida, P. anatis, P. avium, P. canis, P. dagmatis, P. gallinarum, P. langaa, P. stomatis, P. volantium, H. haemoglobinophilus, H. parasuis, H. paracuniculus, H. paragallinarum, and A. capsulatus. This cluster also contained Pasteurella species A CCUG 18782, Pasteurella species B CCUG 19974, Haemophilus taxon C CAPM 5111, H. parasuis type 5 Nagasaki, P. volantium (H. parainfluenzae) NCTC 4101, and P. trehalosi NCTC 10624. The fourth cluster included the type strains of Actinobacillus lignieresii, A. equuli, A. pleuropneumoniae, A. suis, A. ureae, H. parahaemolyticus, H. parainfluenzae, H. paraphrohaemolyticus, H. ducreyi, and P. haemolytica. This cluster also contained Actinobacillus species strain CCUG 19799 (Bisgaard taxon 11), A. suis ATCC 15557, H. ducreyi ATCC 27722 and HD 35000, Haemophilus minor group strain 202, and H. parainfluenzae ATCC 29242. The type strain of P. pneumotropica branched alone to form a fifth group. The branching of the Pasteurellaceae family tree was quite complex. The four major clusters contained multiple subclusters. The clusters contained both rapidly and slowly evolving strains (indicated by differing numbers of base changes incorporated into the 16S rRNA sequence relative to outgroup organisms). While the results presented a clear picture of the phylogenetic relationships, the complexity of the branching will make division of the family into genera a difficult and somewhat subjective task. We do not suggest any taxonomic changes at this time.     

Henry Hurd Rusby: The father of economic botany at the New York Botanical Garden

Henry Hurd Rusby (1855–1940) is one of the outstanding personalities in the history of the New York Botanical Garden (NYBG). He played a significant role, not only in the founding of NYBG in 1891, but also in establishing a strong precedent of research and exploration in the field of economic botany at the new institution. As a result of Rusby’s influence and activity, the study of useful plants formed an important part of NYBG’s original mandate, an institutional commitment that was rejuvenated nearly a century later, with the formation of the Institute of Economic Botany. An indefatigable researcher both in the field and in the herbarium, Rusby left behind a voluminous corpus of published work in systematic and economic botany that is a legacy for modern botanists and pharmacologists.     

Partitioning behaviour of 1-hexanol into lipid membranes as studied by deuterium NMR spectroscopy

Deuterium nuclear magnetic resonance (NMR) spectroscopy was used to study the partitioning behaviour of 1-hexanol specifically deuterated in the alpha-position into model lipid bilayers. In all systems studied, the observed deuterium NMR lineshapes were time-dependent. Initially, 1-hexanol-d2 gave rise to an isotropic deuterium resonance with a different chemical shift from that of aqueous 1-hexanol-d2. After equilibration over a period of days, a broader spectral component characteristic of a spherically-averaged powder-pattern was observed. The quadrupole anisotropy of the 1-hexanol-d2 giving rise to the broad spectrum depended upon the cholesterol content of the membrane. From quantitation of the anisotropic to isotropic deuterium NMR spectra, the partition coefficients of 1-hexanol-d2 in a number of bilayer systems (asolectin and phosphatidylcholine bilayers (the latter with and without cholesterol] were determined. The partitioning of 1-hexanol-d2 into red blood cell membranes, and a suspension of lipids extracted from red blood cell membranes, was also examined. It is suggested that 1-hexanol, and probably other lipophiles, can partition to either the bilayer surface or the bilayer interior in a time-dependent manner.