Enhancing high-order above-threshold dissociation of H2+ beams with few-cycle laser pulses.

High-order (three-photon or more) above-threshold dissociation (ATD) of H(2)(+) has generally not been observed using 800 nm light. We demonstrate a strong enhancement of its probability using intense 7 fs laser pulses interacting with beams of H(2)(+), HD(+), and D(2)(+) ions. The mechanism invokes a dynamic control of the dissociation pathway. These measurements are supported by theory that additionally reveals, for the first time, an unexpectedly large contribution to ATD from highly excited electronic states.

Methanosarcina mazei strain O1M9704, methanogen with novel tubule isolated from estuarine environment.

A new methanogenic isolate, designated as strain O1M9704 (=OCM 667), was isolated from the sediment of the estuarine environment in Eriln Shi, Taiwan. This strain grew on trimethylamine and methanol, but it did not catabolize H2-CO2, acetate, or formate. Cells grew optimally at 37 degrees C with 0.5% NaCl in neutral pH. The cells were stained Gram-negative, nonmotile, irregular coccus 0.3-0.6 microm in diameter. A comparison of 16S rDNA sequences phylogenetically related strain O1M9704 to Methanosarcina mazei. Gas vacuoles were observed both under phase contrast microscope and in thin sections in the electron microscope. Negative stain of electron micrographs showed a novel character of strain O1M9704. with tubule structure extended out of the cells. The tubule structure and gas vacuoles may benefit the adaptation of methanoarchaea in estuarine environment.

Characterization of Methanosarcina mazei N2M9705 isolated from an aquaculture fishpond.

A new methanogenic isolate, designated as strain N2M9705 (=OCM 668), was isolated from an aquaculture fishpond near Wang-gong, Taiwan. This strain grew on trimethylamine and methanol, but it did not catabolize H2-CO2, acetate, or formate. The cells were stained Gram-negative, nonmotile, irregular coccus 0.6-0.8 micrometer in diameter. Gas vacuoles were observed and cell aggregated to form various sizes of granules. Cells grew optimally at 32 degrees -37 degrees C with 1% NaCl. The pH range of growth was 6.2-7.4, and higher pH inhibited the cell growth. The cells grew well in minimal medium, but growth was greatly stimulated by yeast extract and peptone. A comparison of 16S rDNA sequences of this organism phylogenetically related to Methanosarcina mazei. This is the first report of methyltrophic methanogenic isolated from an aquaculture fishpond.

Dehydroepiandrosterone sulfate and anovulation increase serum inhibin and affect follicular function during administration of gonadotropins.

To test the hypothesis that testosterone (T) derived from circulating dehydroepiandrosterone sulfate (DS) or produced in excess within the anovulatory ovary is a follicular regulator capable of stimulating inhibin secretion. DS and inhibin were determined by RIA in residual serum samples from in vitro fertilization cycles and analyzed along with other parameters using analysis of variance and stepwise multiple linear regression after log transformation of the RIA data. It was predicted that the serum concentration of inhibin would be higher in women with anovulation than in normal subjects and that the serum inhibin concentration would have a positive regression coefficient on the serum DS concentration. The serum concentrations of inhibin (P < 0.01) and estradiol (P < 0.001) on the day of hCG treatment were higher in women with anovulation than in normal subjects, as was the number of oocytes retrieved (P < 0.001). The FSH and LH doses (both P < 0.005) and age (P < 0.001) were significantly lower, and the average duration of gonadotropin therapy was 1 day shorter (P < 0.001) in anovulatory patients. There was no significant difference in serum DS (P > 0.2). Regression analysis showed that serum inhibin was positively related to the number of oocytes (P < 0.001) and serum DS (P = 0.05), with an increase in anovulatory subjects (P < 0.025). The duration of treatment with gonadotropins was related positively to the patient's age (P < 0.001) and negatively to serum DS (P < 0.025), with a decrease in anovulatory subjects (P < 0.025). The number of oocytes obtained was negatively related to age (P < 0.001) and positively to serum DS (P < 0.005). These data are consistent with a stimulatory effect of follicular T derived from either circulating DS or the anovulatory ovary, which affects the secretion of inhibin, the duration of gonadotropin treatment, and the number of oocytes retrieved.

[Effects of solute on growth and intracellular salt concentration of Pediococcus halophilus CCRC 12884 isolated from Inyu mash].

Optimal growth conditions for Pediococcus halophilus CCRC 12884, a halophilic strain of lactic acid bacterium isolated from Inyu (black bean sauce) mash, were MRS broth with 10% NaCl and 35 degrees C of incubation temperature. The NaCl in media could not be replaced by sucrose or glycerol of same concentrations, and under certain osmolarity, growth of P. halophilus CCRC 12884 only in NaCl was better than that in NaCl plus sucrose or glycerol. To determine effects of monovalent and divalent ions on P. halophilus CCRC 12884, it was found that close relations were present among Na+, K+ and PO4(-3). The intracellular concentration of Na+ in P. halophilus CCRC 12884 was not correspondent to its extracellular concentration of NaCl, but intracellular K+ and quaternary ammonium compounds significantly increased as extracellular NaCl increased. Adding 0-3.5 mM betaine to media with different contents of NaCl would not affect the growth of this halophilic bacterium. On feeding 14C-ethanolamine to the bacterium, no intracellular 14C-betaine was synthesized.