Profiling of Coumarins in Peucedanum palustre (L.) Moench Populations Growing in Finland

The coumarin composition of Peucedanum palustre (L.) Moench populations growing in Finland was investigated. A total of 132 flowering P. palustre specimens from 43 locations in southern and central Finland were collected, divided into root, stem, leaf, and umbel samples, and analyzed by HPLC. HPLC coupled to high‐resolution mass spectrometry was used to aid the identification of coumarins. A total of 13 coumarin‐structured compounds were quantitatively analyzed from the samples. The coumarin profile of root samples was found to differ from the aerial plant parts. The main coumarins in roots were oxypeucedanin and columbianadin. In aerial parts, peulustrin isomers were the most abundant coumarin components. Umbels and leaves also contained a considerable amount of umbelliprenin, which was only found in traces in roots. Based on hierarchical cluster analysis of the coumarin profiles, some populations shared common characteristics. The most distinct property connecting certain populations was their high peulustrin content. Another notable common property between some populations was the high umbelliprenin content in aerial plant parts. Some populations were clustered together due to their low overall coumarin content.     

Cytochrome c‐based domain modularity governs genus‐level diversification of electron transfer to dissimilatory nitrite reduction

The genus Neisseria contains two pathogenic species (N. meningitidis and N. gonorrhoeae) in addition to a number of commensal species that primarily colonize mucosal surfaces in man. Within the genus, there is considerable diversity and apparent redundancy in the components involved in respiration. Here, we identify a unique c‐type cytochrome (c_N) that is broadly distributed among commensal Neisseria, but absent in the pathogenic species. Specifically, c_N supports nitrite reduction in N. gonorrhoeae strains lacking the cytochromes c₅ and CcoP established to be critical to NirK nitrite reductase activity. The c‐type cytochrome domain of c_N shares high sequence identity with those localized c‐terminally in c₅ and CcoP and all three domains were shown to donate electrons directly to NirK. Thus, we identify three distinct but paralogous proteins that donate electrons to NirK. We also demonstrate functionality for a N. weaverii NirK variant with a C‐terminal c‐type heme extension. Taken together, modular domain distribution and gene rearrangement events related to these respiratory electron carriers within Neisseria are concordant with major transitions in the macroevolutionary history of the genus. This work emphasizes the importance of denitrification as a selectable trait that may influence speciation and adaptive diversification within this largely host‐restricted bacterial genus.     

Synthesis, cytotoxicity, and antitumor activity of lantadene-A congeners

Five new derivatives of the pentacyclic triterpenoid lantadene A (= 22beta-angeloyloxy-3-oxoolean-12-en-28-oic acid; 1) from the leaves of Lantana camara L. were synthesized, characterized, and screened for their cytotoxicities against four human cancer cell lines. The three most-potent compounds, i.e., 1, 4, and 6, with IC50 values in the range of ca. 20-29 microM, were further studied for their in vivo tumor-inhibitory potential upon oral administration in two-stage squamous cell carcinogenesis, using female Swiss albino mice, papilloma being induced by 7,12-dimethylbenz[a]anthracene (DMBA), and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). The results are discussed in terms of structure-activity relationship.     

Bombesin analogs containing alpha-amino-isobutyric acid with potent anticancer activity.

Six octapeptide bombesin (BN) analogs were synthesized by substituting alpha-aminoisobutyric acid (Aib), in place of Ala9 or Gly11, or both, in the [D-Phe6, desMet14]-BN (6-14) sequence: D-Phe6-Gln7-Trp8-Ala9-Val10-Gly11-His12-Leu13-NH2 (P0). Additionally, Leu13 was replaced with isoleucine in two analogs and one of the analogs was butanoylated at the N-terminus. The antiproliferative activity of the analogs was tested in vitro on human pancreatic (MiaPaCa-2) and colon cancer (SW620, HT29 and PTC) cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The analogs demonstrated anticancer activity in the above cell lines at concentrations ranging from 0.01 nM to 1 microM. One of the analogs, P6, was evaluated for in vivo tumor regression in a xenograft model of human primary colon cancer in athymic nude mice and was found to cause significant reduction in tumor volume. NMR and molecular dynamics (MD) simulation studies for this analog revealed the presence of a mixed 3(10)/alpha-helical structure. This study demonstrates that the designed BN analogs retain their anticancer activity after the incorporation of the constrained amino acid, Aib, and are potential molecules for future use in cancer therapy and drug targeting.     

Reversible Inactivation of Nitrate Reductase by NADH and the Occurrence of Partially Inactive Enzyme in the Wheat Leaf

Nitrate reductase from wheat (Triticum aestivum L. cv Bindawarra) leaves is inactivated by pretreatment with NADH, in the absence of nitrate, a 50% loss of activity occurring in 30 minutes at 25°C with 10 micromolar NADH. Nitrate (50 micromolar) prevented inactivation by 10 micromolar NADH while cyanide (1 micromolar) markedly enhanced the degree of inactivation.

A rapid reactivation of NADH-inactivated nitrate reductase occurred after treatment with 0.3 millimolar ferricyanide or exposure to light (230 milliwatts per square centimeter) plus 20 micromolar flavin adenine dinucleotide. When excess NADH was removed, the enzyme was also reactivated by autoxidation. Nitrate did not influence the rate of reactivation.

Leaf nitrate reductase, from plants grown for 12 days on 1 millimolar nitrate, isolated in the late photoperiod or dark period, was activated by ferricyanide or light treatment. This suggests that, at these times of the day, the nitrate reductase in the leaves of the low nitrate plants is in a partially inactive state (NADH-inactivated). The nitrate reductase from moisture-stressed plants showed a greater degree of activation after light treatment, and inactive enzyme in them was detected earlier in the photoperiod.

     

Captive reproduction in Heermann's kangaroo rat,Dipodomys heermanni

This paper summarizes 8 years of captive breeding experience with the endangered Morro Bay kangaroo rat (Dipodomys heermanni morroensis) and the non-endangered Lompoc kangaroo rat (D. h. arenae), a related form used as a surrogate. Kangaroo rats are aggressive and must be caged individually; copulation can only take place when the female is in estrus. The estrous cyle varies, but is usually 14–17 days long; gestation averages 31 days. Data on development of the young, animal health, mortality, and longevity are presented. The productivity of this project is compared with that of another long-term kangaroo rat breeding project in terms of the number of young produced per female per year. A captive breeding program can be initiated with 40–50 reproductive animals as a founder group.     

Efficient plant regeneration system for immature embryos of triticale (x Triticosecale Wittmack)

A range of tissue culture conditions were tested to improve embryo culture frequency, and to develop an efficient plant regeneration system for triticale. Immature embryos (14–21 days post-anthesis) from two triticale genotypes (Hx87-139 and Tahara) were cultured on a commonly used Murashige and Skoog (MS) and on Lazzeri's (L1) basal medium with varied carbon sources, and two different plant growth regulators; 2,4-Dichlorophenoxyacetic acid (2,4-D) and 3,6-Dichloro-2-methoxybenzoic acid (dicamba). Although embryos could be cultured on both media types, L1 based medium was better than MS basal salts for callus induction and somatic embryogenesis, with plant regeneration frequencies up to 11 fold greater on L1 media types. In the presence of dicamba, callus induction was more rapid, that resulted in subsequent regeneration of up to 2 fold more plantlets than from callus induced on medium containing 2,4-D. Maltose appeared to be a superior carbon source during differentiation of callus. Genotype Tahara showed a better regenerative response than Hx87-138, with up to 23 normal, fertile plants being produced from a single embryo when cultured on L1MDic medium, containing maltose (5%) and dicamba (20 mg l^–1). Applications of this tissue culture procedure in triticale improvement through genetic engineering are also discussed.