First-rotation growth and stand structure dynamics of tree species in organic and conventional short-rotation agroforestry systems.

Short-rotation agroforestry systems can potentially maintain agricultural production and promote conservation of soil and biodiversity, especially if grown organically. Hereby, species-specific stand growth determines woody biomass yield and influences management decisions like planting density and harvest requirements. Studies of longer-term growth dynamics in Southern Germany are scarce and none analyzed differences between conventional and organic systems. In this study, four tree species (black alder, black locust, poplar clone Max 3, and willow clone Inger) were planted in an alley-cropping configuration in Southern Germany, grown under organic and conventional systems, and monitored from 2009 to 2012. Growth was assessed with stem base diameter, height, aboveground woody biomass, sprouting, and survival. The tree species did not show a uniform ranking in biometric variables and biomass over time. Four-year mean annual biomass increment (MAI) ranged from 7 to 10 t ha-1 a-1, with poplar and locust having the highest growth rates. Willow had the lowest MAI, as it had a low diameter growth paired with a low wood density, but it developed the highest number of shoots because of increased sprouting in the last year. Size inequality and skewness of the dominant stems increased for all species throughout the years suggesting asymmetric competition. Size inequality as well as mortality was greatest for black locust. Furthermore this was the only species, which developed a right skewed SBD distribution and the highest diameter size range. Size inequality was smallest for poplar and willow, with no or only minimal mortality. Alder was inbetween. For black locust and alder no difference in growth traits between organic and conventional systems appeared after four years. Organic poplar and willow stands performed better than conventional ones after the second year, leaving unclear whether this can be attributed to management or site effect.

Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise.

Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world's ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the approximately 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at approximately 5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity--all in close proximity.

Results of a rural breast health education demonstration project.

The Healthy People 2000-National Health Promotion and Disease Prevention Objectives call for an increase in breast health education to the public to increase women's knowledge about breast cancer and the benefits of screening. A breast health outreach education intervention for community health professionals was designed, implemented, and evaluated. The barriers to continuing education of health professionals of rural areas were addressed. Low-cost, county-based seminars using a comprehensive breast health education curriculum were provided for community health professionals. The intervention demonstrated an increase in a professional's knowledge about breast cancer and breast cancer screening, and an increase in their breast self-examination skills. Six months after intervention, community health professionals reported an increase in the frequency of their breast self-examination performance.

Catechol O-methyltransferase. 10. 5-Substituted 3-hydroxy-4-methoxybenzoic acids (isovanillic acids) and 5-substituted 3-hydroxy-4-methoxybenzaldehydes (isovanillins) as potential inhibitors.

A series of 5-substituted 3-hydroxy-4-methoxybenzoic acids (isovanillic acids) and -benzaldehydes (isovanillins) have been synthesized and evaluated as inhibitors of rat liver catechol O-methyltransferase. The compounds exhibited either noncompetitive or competitive patterns of inhibition when 3,4-dihydroxybenzoic acid was the variable substrate. The benzaldehydes were significantly more potent inhibitors than the corresponding benzoic acids, and electron-withdrawing substituents in the 5 position greatly enhanced their inhibitory activity.

Catechol O-methyltransferase. 11. Inactivation by 5-hydroxy-3-mercapto-4-methoxybenzoic acid.

5-Hydroxy-3-mercapto-4-methoxybenzoic acid was synthesized as a potential affinity-labeling reagent for catechol O-methyltransferase (COMT, EC 2.1.1.6). This compound was shown to produce noncompetitive inhibition of COMT when assayed in the presence or absence of the reducing agent, dithiothreitol (DTT). If COMT was assayed in the absence of DTT, the compound was shown to be a more potent inhibitor (Kis = 59.9 +/= 15.9 mumol; Kii = 30.2 +/- 5.8 mumol) than if the assays were conducted in the presence of the reducing agent (Kis = 1140 +/- 233 mumol; Kii = 743 +/- 141 mumol). The potent inhibitory effects produced in the absence of DTT could be partially reversed by the addition of DTT to the incubation mixture or by dialysis of the modified enzyme against DTT -containing buffer. These data suggest that in the absence of DTT, 5-hydroxy-3-mercapto-4-methoxybenzoic acid serves as an affinity-labeling reagent for COMT by reaction of the 3-mercapto group of the ligand with an active-site sulfhydryl group. This ligand-protein disulfide bond can be reduced with DTT with subsequent reversal of the inhibitory effects.

Potential inhibitors of S-adenosylmethionine-dependent methyltransferases. 4. Further modifications of the amino and base portions of S-adenosyl-L-homocysteine.

Structural analogues of S-adenosyl-L-homocysteine (L-SAH), with modifications in the amino acid or base portions of the molecule, have been synthesized and evaluated for their abilities to inhibit the transmethylations catalyzed by catechol O-methyltransferase (COMT), phenylethanolamine N-methyltransferase (PNMT), histamine N-methyltransferase (HMT), hydroxyindole O-methyltransferase (HIOMT), and indoleethylamine N-methyltransferase (INMT). From these studies some interesting and potentially useful differences in the structural features of L-SAH needed to produce maximal binding to these methyltransferases were detected. This paper provides evidence that 8-azaadenosyl-L-homocysteine is a potent and selective inhibitor of HIOMT, whereas N6-methyladenosyl-L-homocysteine and N6-methyl-3-deazaadenosyl-L-homocysteine are selective inhibitors in INMT. In contrast, it was found that S-tubercidinyl-L-homocysteine was a fairly potent, but nonselective inhibitor of all of the methyltransferases studied. The differences and the similarities in the requirements for the binding of SAH to methyltransferases which were detected in this study and earlier studies from our laboratory, are described. The possibilites of utilizing differences in binding requirements for the design of SAH analogues as specific inhibitors of methyltransferases are discussed.

Potential inhibitors of S-adenosylmethionine-dependent methyltransferases. 6. Structural modifications of S-adenosylmethionine.

Structural analogues of S-adenosyl-L-methionine (SAM), with modifications in the amino acid, sugar, or base portions of the molecule, have been synthesized and evaluated as either inhibitors and/or substrates for the enzymes catechol O-methyltransferase, phenylethanolamine N-methyltransferase, histamine N-methyltransferase, and hydroxyindole O-methyltransferase. To evaluate these analogues as substrates for SAM-dependent methyltransferases, the corresponding methyl-14C compounds were prepared and tested for their abilities to donate their methyl group to the appropriate acceptor molecules. In addition, the unlabeled SAM analogues were tested for their inhibitory activities in these same transmethylation reactions. In general, it could be conlcuded from these studies that methyltransferases show very strict specificity for the structural features of SAM. This strict specificity holds for the enzymatic binding and methyl-donating abilities of this molecule. In fact, it could be concluded from the results of this study that methyltransferases show a higher specificity for the structural features of the substrate L-SAM than for the structural features of the product S-adenosyl-L-homocysteine (L-SAH).