Transformation and motility of human platelets: details of the shape change and release reaction observed by optical and electron microscopy

Blood platelets from 10 normal human subjects have been examined with a sensitive differential interference contrast (DIC) microscope. The entire transformation process during adhesion to glass is clearly visible and has been recorded cinematographically, including the disk to sphere change of shape, the formation of sessile protuberances, the extension and retraction of pseudopodia, and the spreading, ruffling, and occasional regression of the hyalomere. The exocytosis of intact dense bodies can be observed either by DIC microscopy, or by epifluorescence microscopy in platelets stained with mepacrine. Details of fluorescent flashes indicate that the dense bodies usually release their contents extracellularly, may do so intracytoplasmically under the influence of strong, short wavelength light on some preparations of mepacrine-stained platelets. The release of one or more dense bodies leaves a crater of variable size on the upper surface of the granulomere. Such craters represent the surface component of the open canalicular system and their formation and disappearance can be directly observed. Because these techniques permit quantitation of several parameters of motility which are not readily observable by other techniques, it is suggested that high extinction DIC microscope examination may become a rapid and useful method of studying congenital and acquired platelet disorders. Many features of platelet transformation have been confirmed and extended by scanning electron micrographs. These can in turn be interpreted by reference to time-lapse films of living platelets.     

An improved method of typing hair sheath cells using the PGM3 locus following starch gel electrophoresis

Summary The PGM₃ locus, like the PGM₁ locus, is shown to be easily demonstrated in hair sheath cells using starch gel electrophoresis. The discriminating power of the total system (PGM₁ and PGM₃) on starch gel electrophoresis closely approaches that observed by isoelectric focusing of the PGM₁ locus. Family studies of the PGM₃ locus variants in hair sheath cells confirm that the alleles responsible are inherited in a Mendelian fashion independent of the PGM₁ locus.     

Procedures for the production and separation of H and M antigens in histoplasmin: Chemical and serological properties of the isolated products

Two strains of Histoplasma capsulatum were required to prepare maximum yields of H and of M antigen from histoplasmin. The antigens were separated and partially purified by a series of procedures yielding an overall recovery of 70 to 90% of the individual antigens. Stable products suitable for use as reference products were obtained when the final purification step employed DEAE-cellulose with phosphate buffer elution at increasing molarity and decreasing pH. A final step of purification of each antigen with slab acrylamide gel electrophoresis gave products which were highly reactive and specific in a variety of serological tests with sera from persons with proven cases of histoplasmosis and with natural infections of heterologous deep mycoses. These antigens were maximally active at concentrations of 2 to 16 g protein in the complement fixation, capillary precipitin, microimmunodiffusion, or immunoelectrophoresis tests; 0.5 g gave a maximum delayed cutaneous hypersensitivity reaction in homologously infected animals and caused no appreciable reaction in control animals. Although these antigens appeared to be specific when tested with sera from persons with natural infections, the M and H antigens demonstrated the presence of an additional antigen reacting with sera of rabbits immunized with cell membrane and cell particulate fractions of Blastomyces dermatitidis. After purification by electrophoresis, both the H and M antigens of some preparations showed some decomposition and loss of reactivity after storage at 5 C for more than six months. The overall results suggest that the purified H and M antigens of Heiner (12) have multiple serological reactivity and may function in precipitin reactions, complementfixing reactions, hemagglutination of formalin-fixed goose red blood cells, and as antigens for delayed cutaneous tests.     

An examination of the developing cotton fiber: Wall and plasmalemma

Summary The ultrastructure of developing cotton fibers has been examined using novel modifications of the techniques of surface replication, freeze-etching and thin-sectioning. The fiber surface was found to be coated with a lamellar cuticle, which is stretched and thinned as the fiber elongates. It is marked by bars which run parallel with the fiber long axis. Beneath the cuticle, the outermost microfibrils of the primary wall lie parallel with the fiber axis, while those adjacent to the plasma membrane are transverse. Primary wall microfibrils are present in bundles, disposed in left-handed and right-handed helices, which correspond with the fibrils observed optically. Microfibrils within bundles form in-phase waves, with wavelengths and amplitudes in the ranges 0.3–7 m and 0.01–0.1 m in primary and secondary walls respectively. As elongation proceeds bundles become displaced towards the cell axis. Microfibrils of the secondary wall, disposed around the cell as fast helices, are similarly bundled and wavy (though with a reduced amplitude). In surface-replicas, large (20–30 nm) granules are present on the cytoplasmic face of the wall which probably correspond with 20–40 nm low prominences visible on freeze-etch EF plasma membrane fracture faces. It is proposed that these may be microfibril-synthesizing centers. Plasma membranes fracture such that the membrane-associated-particles segregate 6040 between P and E fracture moieties, but the prominence and total number of these particles is reduced at the stage of secondary wall formation as compared with primary wall formation. Beneath the plasmalemma the axes of microtubules parallel secondary wall microfibril orientation. Cross-bridges, which stain heavily after glutaraldehyde/tannic acid fixation, link microtubules to plasma membrane. The use of butyl benzene to cement fragments of cotton fibers, employed in this work, may prove useful in other freeze-etch studies of long fibers which are readily ruptured during preparation.     

STUDIES OF HAWAIIAN FRESHWATER AND SOIL ALGAE II. ALGAL COLONIZATION AND SUCCESSION ON A DATED VOLCANIC SUBSTRATE1,2

Spatial studies of colonization and succession of soil algae and chemical analyses of the various soils on the cinde cone of Kilauea Iki in Hawaii Volcanoes National Park, Hawaii are outlined. There is a positive correlation between the diversity and quantity of soil algae with nutrient levels and organic matter accumulation in each locale. Three distinct edaphic-biotic zones existing in this area are differentially revealed by the soil chemical composition, quantity and diversity of soil algae, and as evident variations in higher plant growth and colonization. Varying colonization and successional phases of higher plant growth around standing and fallen tree snags killed by volcanic activity also reflect variations in the soil algal flora. These variations appear largely as a function of differential water interception, absorption, and retention as well as differential accumulation of organic matter, and the initiation of various biogeochemical cycles.     

24-methylenepollinastanol and 24-dehydropollinastanol—two sterols of pollen

The esterified and unesterified sterol fractions of bee-gathered mixed pollens were examined, and total sterol composition was determined. Two new sterols of pollens, 14α-methyl-9β,19-cyclo-5α-cholest-24-en-3β-ol (24-dehydropollinastanol) and 14α-methyl-5α-ergost-24(28)-en-3β-ol (24-methylenepollinastanol) were isolated and identified. Both sterols were found primarily in the esterified sterol fraction, and 24-methylenepollinastanol accounted for 43% of the sterols of this fraction. 24-Dehydropollinastanol and four other sterols which also contain a 9β,19-cyclopropane ring were found only in the esterified sterol fraction. 24-Methylenecholesterol was the major sterol of the unesterified sterol fraction.     

A 13C NMR study of the biosynthesis of the anthraquinone dothistromin by Dothistroma pini

A ¹³C-NMR study of the biosynthesis of dothistromin by Dothistroma pini was undertaken. The biosynthetic labelling pattern in this bistetrahydr     

S49 lymphoma wild type and variant clones contain normal calcium dependent regulator.

Calcium dependent regulator is present in wild-type S49 lymphoma cells, in the variant that is deficient in adenylate cyclase activity (AC-), and in the uncoupled variant (UNC). The electrophoretic mobility and the ability to stimulate cyclic nucleotide phosphodiesterase of the calcium dependent regulator from each of these three clones are indistinguishable from those of the modulator protein isolated from bovine brain. Calcium dependent regulator does not appear to be involved in the defect responsible for the UNC or AC- variants.     

The biology of a giant dung-beetle (Heliocopris dilloni) (Coleoptera: Scarabaeidae)

Heliocopris dilloni is the largest dung-beetle found in the Tsavo National Park, Kenya, which during the biannual rainy seasons comprises the most important agency of elephant dung removal. The species is shown to exhibit considerable morphological variation. The mode of construction of the brood chamber is described together with details of development from egg to pupa. It is suggested that the depth to which these beetles burrow is related to avoiding the extreme climate near the surface and to predator avoidance.