Primary Succession on a Hawaiian Dryland Chronosequence

We used measurements from airborne imaging spectroscopy and LiDAR to quantify the biophysical structure and composition of vegetation on a dryland substrate age gradient in Hawaii. Both vertical stature and species composition changed during primary succession, and reveal a progressive increase in vertical stature on younger substrates followed by a collapse on Pleistocene-aged flows. Tall-stature Metrosideros polymorpha woodlands dominated on the youngest substrates (hundreds of years), and were replaced by the tall-stature endemic tree species Myoporum sandwicense and Sophora chrysophylla on intermediate-aged flows (thousands of years). The oldest substrates (tens of thousands of years) were dominated by the short-stature native shrub Dodonaea viscosa and endemic grass Eragrostis atropioides. We excavated 18 macroscopic charcoal fragments from Pleistocene-aged substrates. Mean radiocarbon age was 2,002 years and ranged from < 200 to 7,730. Genus identities from four fragments indicate that Osteomeles spp. or M. polymorpha once occupied the Pleistocene-aged substrates, but neither of these species is found there today. These findings indicate the existence of fires before humans are known to have occupied the Hawaiian archipelago, and demonstrate that a collapse in vertical stature is prevalent on the oldest substrates. This work contributes to our understanding of prehistoric fires in shaping the trajectory of primary succession in Hawaiian drylands.     

Direction of locomotion in clones of non-neoplastic fibroblasts and their neoplastic derivatives

The locomotion of cloned mouse fibroblasts, non-neoplastic and their spontaneously transformed neoplastic derivatives was compared by means of cinephotomicrography. The spontaneous transformants grow as invasive transplantable sarcomas, whereas the non-neoplastic fail to grow as tumors, and do not show the diagnostic characteristics of neoplastic cells in culture; these include certain morphologic alterations, growth in soft agar, and susceptibility to killing by activated macrophages. The non-neoplastic cells tended to maintain the same direction of locomotion in sequential 2.5 h periods, whereas the neoplastic cells did not. Thus, cells in all non-neoplastic lines exhibited a “persisten” walk while cells from the neoplastic lines had a random pattern of locomotion. No relationship between cell density and randomness of locomotion was observed, and the non-neoplastic cells appeared to grow as rapidly as the neoplastic cells. However, the neoplastic cells had higher rates of locomotion possibly associated with their invasive potential in vivo. The deficient amount of lamellar cytoplasm in the neoplastic cells and the high migration rate may account for their random pattern of locomotion.     

Identification of metabolites of phenylacetic acid in rat brain by plasma desorption mass spectrometry

Mass spectra of acyl hydroxamates may be obtained directly, without prior derivatization or gas chromatography, by the new technique of plasma desorption mass spectrometry. Authentic alkyl and aryl hydroxamates showed the expected protonated molecular ions when isobutane was used as the carrier gas. Advantage was taken of this novel technique to identify phenylacetyl-CoA and phenylbutyric acid in brain extracts obtained from young rats after a loading dose of phenylacetic acid. The formation of these metabolic products lends strong support to our suggestion that brain dysfunction induced by phenylacetic acid in experimental phenylketonuria may be due to decreased availability of CoA and acetyl-CoA in the rapidly developing brain.     

A tailed primers protocol to identify the association of eNOS gene variable number of tandem repeats polymorphism with ischemic stroke in Chinese Han population by capillary electrophoresis

Endothelial nitric oxide synthase (eNOS) plays an important role in mediating endothelium-dependent vasodilatation and antithrombotic action and is thus involved in the development of ischemic stroke (IS). Controversial results regarding the association of eNOS gene variable number of tandem repeats (VNTR) polymorphism with IS have been reported by conventional PCR-polyacrylamide gel electrophoresis methods. We aimed to identify any common association of eNOS gene VNTR polymorphism with IS in Chinese Han population by capillary electrophoresis (CE). The VNTR polymorphism of 27 bp within the eNOS intron-4 was determined by CE with specially designed tailed primers in Chinese Han patients with IS (n = 457) and matched elderly controls without IS (n = 457). Significant differences in BMI, WHR, hypertension, diabetes, smoking, TG, HDL, LDL, LDL, and FBG were observed between cases and controls. The distributions of eNOS VNTR polymorphism were not significantly associated with IS after adjustment for cardiovascular risk factors (OR = 1.18, 95% CI: 0.82–1.69). This finding was consistent with the further meta-analysis in Asians. The meta-analysis in Americans demonstrated that 4a/4b + 4a/4a genotype was significantly associated with IS risk with an OR of 1.54 (95% CI, 1.09–2.17) compared with the 4b/4b genotype. Our data suggests that BMI, WHR, hypertension, diabetes, smoking, TG, LDL, and FBG may increase the risk of IS. However, eNOS VNTR polymorphism may be not an independent major contributor for IS in Chinese Han population. The VNTR polymorphism might be associated with IS in Americans based on meta-analysis.     

SOME CHARACTERISTICS OF THE SPERM ATTRACTANT FROM OEDOGONIUM CARDIACUM1

A bioassay for the sperm attractant from Oedogonium cardiacum was developed. The attractant was confirmed to be highly water soluble, destroyed by heating to 100 C and by dilute acid or alkali. It was fractionated by gel filtration with the attractant accompanied by yellow pigments. It has it molecular weight between 500 and about 1500, based on gel filtration, ultrafiltration, and dialysis. Freezing changes this to both larger and smaller molecules. It appears to have cationic groups. A paper chromatographic separation was found that divided the pigment into at least 3 major bands, one of which was closely associated with the attractant. An absorption spectrum of this pigment showed 1 peak in the visible spectrum at 417 mμ and 3 well-defined peaks in the ultraviolet region. The lack of a peak at 280 mμ indicates the attractant is not a polypeptide.