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PubMed2007

Isolation and structure elucidation of procyanidin oligomers from Saskatoon berries (Amelanchier alnifolia).

Proanthocyanidin oligomers with different degrees of polymerization were isolated from Saskatoon berries (Amelanchier alnifolia) by means of gel adsorption and normal-phase liquid chromatography. The proanthocyanidins were identified using electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and thiolytic degradation coupled with reversed-phase liquid chromatography. The results established that Saskatoon berries contain proanthocyanidins from dimers through heptamers and higher polymers. Saskatoon proanthocyanidins are essentially of procyanidin type, consisting mainly of epicatechin units linked by B-type bonds. The simple procyanidin profile of Saskatoon berries allowed the procyanidins to be separated precisely according to their degrees of polymerization. In the future they can be used as standard compounds for qualitative and quantitative analysis of procyanidins as well as for elucidation of the biological activities of proanthocyanidins.

Chromatography, High Pressure Liquid↗
PubMed2005

Reversion of human Pgp-dependent multidrug resistance by new sesquiterpenes from Zinowiewia costaricensis.

In an intensive study of South American medicinal plants, herein we report the isolation, structure elucidation and biological activity of fourteen new and five known dihydro-beta-agarofuran sesquiterpenes from the leaves of Zinowiewia costaricensis (1-19). Their structures were determined by means of (1)H and (13)C NMR spectroscopic studies, including homonuclear and heteronuclear correlation experiments. The absolute configurations of the new compounds were determined by CD studies, chemical correlations or biogenetic grounds. All the natural compounds and derivative 20 have been tested on human MDR1-transfected NIH-3T3 cells, to determine their ability to revert the multidrug resistance phenotype due to P-glycoprotein overexpression. Six compounds from this series (1, 8, 11, 12, 13 and 14) showed similar effectiveness to the classical P-glycoprotein modulator verapamil when reversing resistance to daunorubicin, but it is up to sixteen times greater than that of verapamil when reversing resistance to vinblastine. The structure-activity relationships are discussed.

3T3 Cells↗
PubMed2001

Components of male aggregation pheromone of strawberry blossom weevil, Anthonomus rubi herbst. (Coleoptera:Curculionidae).

The strawberry blossom weevil, Anthonomus rubi, is a major pest of strawberries in the United Kingdom and continental Europe. As part of a project to develop noninsecticidal control methods, the pheromone system of this species was investigated. Comparison of volatiles produced by field-collected, overwintering individuals of each sex led to identification of three male-specific compounds--(Z)-2-(3,3-dimethylcyclohexylidene)ethanol, (cis)-1-methyl-2-(1-methylethenyl)cyclobutaneethanol, and 2-(1-methylethenyl)-5-methyl-4-hexen-1-ol (lavandulol)--in amounts of 6.1, 1.2, and 0.82 microg/day/ male. The first two compounds are components of the aggregation pheromone of the boll weevil, Anthonomus grandis, grandlure II and grandlure I, respectively. Grandlure I was the (1R,2S)-(+) enantiomer and lavandulol was a single enantiomer, although the absolute configuration was not determined. Trace amounts of the other two grandlure components (Z)-(3,3-dimethylcyclohexylidene)acetaldehyde (grandlure III) and (E)-(3,3-dimethylcyclohexylidene)acetaldehyde (grandlure IV) were also detected. (E,E)-1-(1-Methylethyl)-4-methylene-8-methyl-2,7-cyclo-decadiene (germacrene-D), a known volatile from strawberry plants, Fragaria ananassa, was collected in increased amounts in the presence of pheromone-producing weevils. Male weevils only produced pheromone on F. ananassa and not on scented mayweed, Matracaria recutita, or cow parsley, Anthriscus sylvestris, although these are known food sources. In field trials using various combinations of synthetic grandlures I, II, III, and IV and lavandulol, significantly more weevils were caught in traps baited with blends containing grandlure I and II and lavandulol than in those baited with blends without lavandulol or unbaited controls. Addition of grandlure III and IV had no significant effect on attractiveness. Horizontal sticky traps were found to be more effective than vertical sticky traps or standard boll weevil traps. In mid-season females predominated in the catches, but later more males than females were trapped.

Animals↗
PubMed2001

Intraplant distribution of Acalitus essigi (Acari: Eriophyoidea) on blackberries (Rubus fruticosus agg.).

Specialised phytophagous arthropods often display high levels of specificity to particular sites on their host plant. In this paper we examine the occupation of microhabitats and aggregation patterns of the eriophyoid mite, Acalitus essigi (Hassan), on its host plant, European blackberry (Rubus fruticosus L. aggregate), a plant that undergoes significant seasonal changes in its morphology. A. essigi was found to be a refuge inhabiting species. It resided in bud and leaf axil microhabitats on both primocanes and fructocanes and also occupied berry and bract microhabitats on fructocanes. Population fluctuations within the different microhabitats were evident across seasons. From summer to winter, populations significantly declined in bract and leaf axil microhabitats, but significantly increased within bud microhabitats where overwintering took place as slowly reproducing colonies. Live fruit and young shoots were also identified as overwintering sites. A. essigi populations displayed an aggregated distribution both within and between individual blackberry canes. Within primocanes A. essigi were aggregated in the lower 20% of cane length. On fructocanes aggregation of A. essigi was in the lower 20% and especially in the upper 20% of cane length. In spring A. essigi was confirmed to emerge from bud overwintering sites and colonise shoots mainly in the lower third of the previous season's primocanes, suggesting limited dispersal away from overwintering sites. It is proposed that biotic factors such as tissue age, microhabitat morphology and limited ambulatory dispersal capabilities are responsible for the aggregation pattems of this mite.

Animals↗
PubMed2001

Seasonal occurrence of specialist and generalist insect predators of spider mites and their response to volatiles from spider-mite-infested plants in Japanese pear orchards.

In two adjacent Japanese pear orchards (orchards I and 2), we studied the seasonal occurrence of the Kanzawa spider mite. Tetranychus kanzawai, and its predators. Also the response of these predators to the volatiles from kidney bean plants infested with T kanzawai was investigated using trap boxes in orchard 1. The mite density in orchard 1 was unimodal. with one peak at the end of August. In this orchard, population development of the specialist insect predators, Scolothrips takahashii, Oligota kashmiria benefica and Stethorus japonicus was almost synchronized with that of the spider mites. These predators disappeared when the density of their prey became very low in mid-September. Both S. takahashii and O. kashmirica benefica abruptly increased in number in orchard 2 when the spider mite population in orchard 1 decreased. These results suggested that some of the predators migrated from orchard 1 to orchard 2. In this period, predator-traps with T kanzawai-infested bean plants attracted significantly more S. takahashii than traps with uninfested plants. Very few individuals of S. japonicus and O. kashimirica benefica were found in the traps, despite their abundance in orchard 1. The generalist insect predator, Orius sp., was attracted to the traps throughout the experimental period irrespective of the density of spider mites, although this predator was never observed inside the orchards.

Animals↗
PubMed2002

Maximum likelihood inference for multivariate frailty models using an automated Monte Carlo EM algorithm.

We present a maximum likelihood estimation procedure for the multivariate frailty model. The estimation is based on a Monte Carlo EM algorithm. The expectation step is approximated by averaging over random samples drawn from the posterior distribution of the frailties using rejection sampling. The maximization step reduces to a standard partial likelihood maximization. We also propose a simple rule based on the relative change in the parameter estimates to decide on sample size in each iteration and a stopping time for the algorithm. An important new concept is acquiring absolute convergence of the algorithm through sample size determination and an efficient sampling technique. The method is illustrated using a rat carcinogenesis dataset and data on vase lifetimes of cut roses. The estimation results are compared with approximate inference based on penalized partial likelihood using these two examples. Unlike the penalized partial likelihood estimation, the proposed full maximum likelihood estimation method accounts for all the uncertainty while estimating standard errors for the parameters.

Algorithms↗
PubMed2002

Quality characteristics of red raspberry fruit spread made with four sweeteners.

Red raspberry fruit spreads sweetened with sugar (S) or raspberry, red grape, or apple juice concentrates were processed by inversion and analyzed for chemical, physical, and sensory properties at 1, 12, and 24 weeks. All pH values were between 3.0 and 3.5 while all aw were above 0.81. Samples were dark red but became duller over time. Viscosities and total solids were lower (p < 0.05) in juice sweetened products than in S. Sensory evaluations improved over time for all samples, but were always higher (p < 0.05) for S. Mold was detected in all samples at 24 weeks. Acceptable products were prepared using fruit juice concentrates but inversion processing was not recommended for fruit spread preparation.

Food Handling↗
PubMed2003

4-coumarate:CoA ligase gene family in Rubus idaeus: cDNA structures, evolution, and expression.

The enzyme 4-coumarate:CoA ligase (4CL) activates cinnamic acid and its hydroxylated derivatives by forming the corresponding CoA thioesters. These serve as substrates for biosynthesis of phenylpropanoid-derived end-products that are important determinants of fruit quality in raspberry (Rubus idaeus L.). In higher plants, 4CL is typically encoded by a gene family. To investigate the participation of distinct 4CL genes in the process of fruit ripening, we have characterized this gene family in raspberry. By complementing a PCR-based homology search with low-stringency cDNA library screening, we have isolated three classes of raspberry 4CL cDNAs (Ri4CL1, Ri4CL2, and Ri4CL3). Phylogenetic analysis places the three raspberry 4CL gene family members into two distinct groups, a pattern consistent with an ancient divergence from an ancestral progenitor. Quantitative RT-PCR assay reveals a differential pattern of transcription of each of the three genes in various organs, as well as distinct temporal patterns of expression during flower and fruit development. The regulatory elements thus appear to have evolved independently of the genes themselves. Based on phylogenetic classification, expression patterns and recombinant protein activities the different Ri4CL genes are likely to participate in different biosynthetic pathways leading to the various phenylpropanoid-derived metabolites that help create flavor and color in raspberry fruit.

Cloning, Molecular↗
PubMed2004

[The red face].

Facial erythema may not only present clinically as a distinct entity, but can also be a symptom of other diseases. It is seen in common dermatoses such as eczema, psoriasis, acne and urticaria, as well as in rarer conditions such as disorders of keratinization, infectious diseases, porphyrias and neoplasia. Facial erythema may also present as a symptom of carcinoid syndrome, drug allergies, cardiac disease or in rare cases as a feature of Bloom's syndrome, sarcoidosis, lymphoma, amyloidosis and other disease processes. We would like to concentrate on the practical aspects of facial erythema as a presenting symptom, rather than discussing every disease in detail.

Dermatitis, Photoallergic↗
PubMed2003

Co-existing sensitivity to metronidazole and isothiazolinone.

A 68-year-old woman developed allergic contact dermatitis to topical metronidazole gel as proven by positive patch tests to the gel and to metronidazole. She was also allergic to methylchloroisothiazolinone and methylisothiazolinone (MC/MI). The similarity between the two molecules and the fact that the patient reacted to the gel after the very short incubation period of 1 day (i.e. not long enough for acquiring an active sensitization) makes the possibility of a cross-reaction between these substances very plausible. As the isothiazolinones are widely used and comprise an important and relatively frequent cause of allergic contact dermatitis, a cross-reactivity with metronidazole means that perhaps there should have been more cases of metronidazole allergy is more common than the current literature suggests.

Aged↗
PubMed2001

Analysis of segregation data from selfed progeny of allopolyploids.

This paper discusses the inference of parental genotype based on segregation data from selfed progeny of allopolyploids when there is incomplete information about genotypes and when alleles are codominant or null. The distinct alleles that are present in a genotype are assumed to be known, but not the frequency with which they occur. These assumptions may be appropriate when genotypes are deduced from DNA or protein banding patterns on electrophoretic gels. A computer program, SELF, is described that can generate all possible parental genotypes and rank them on the basis of their agreement with the progeny data. The program caters for tetraploids, hexaploids and octoploids. The methods are illustrated using data from a study of the inheritance of isoenzymes in selfed progeny of octoploid strawberry cultivars.

Alleles↗
PubMed2003

What can morphology and isozymes tell us about the history of the Dryas integrifolia-octopetala complex?

An earlier study of the morphological variation in the circumpolar genus Dryas in Greenland revealed that populations in east Greenland are highly variable and this variation was interpreted as a hybrid zone between D. octopetala and D. integrifolia. It was proposed that populations of Dryas in east Greenland immigrated postglacially from Svalbard. The purpose of our study was to investigate the population structure of the Dryas integrifolia-octopetala complex using a combination of morphological and genetic characters. Populations of Dryas were sampled in Greenland, Svalbard, Iceland and north Scandinavia (Sweden). The morphological traits clearly separated west Greenland from Svalbard, Iceland and north Scandinavia. A large number of individuals from east Greenland and some from north Greenland could be interpreted as hybrids between the morphs. The genetic pattern was, however, partly different as the greatest amount of differentiation among regions was found between west and north Greenland (FRT = 0.65). The highest degree of genetic variation appeared within east Greenland. This was in accordance with the putative hybrid origin of the populations, as concluded based on the morphological results. The total amount of genetic differentiation found among the six regions (FRT = 0.61) was larger than between the two species (FRT = 0.44). The genetic pattern matched the proposed postglacial migration routes.

Climate↗
PubMed2002

Isolation, cloning and expression of a multifunctional O-methyltransferase capable of forming 2,5-dimethyl-4-methoxy-3(2H)-furanone, one of the key aroma compounds in strawberry fruits.

Strawberry fruits contain an uncommon group of key aroma compounds with a 2,5-dimethyl-3(2H)-furanone structure. Here, we report on the methylation of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) to 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMMF) by a S-adenosyl-L-methionine dependent O-methyltransferase, the cloning of the corresponding cDNA and characterization of the encoded protein. Northern-hybridization indicated that the Strawberry-OMT specific transcripts accumulated during ripening in strawberry fruits and were absent in root, petiole, leaf and flower. The protein was functionally expressed in E. coli and exhibited a substrate specificity for catechol, caffeic acid, protocatechuic aldehyde, caffeoyl CoA and DMHF. A common structural feature of the accepted substrates was a o-diphenolic structure also present in DMHF in its dienolic tautomer. FaOMT is active as a homodimer and the native enzyme shows optimum activity at pH 8.5 and 37 degrees C. It does not require a cofactor for enzymatic activity. Due to the expression pattern of FaOMT and the enzymatic activity in the different stages of fruit ripening we suppose that FaOMT is involved in lignification of the achenes and the vascular bundles in the expanding fruit. In addition, it is concluded that the Strawberry-OMT plays an important role in the biosynthesis of strawberry volatiles such as vanillin and DMMF.

Adenosine↗
PubMed2004

Volkensin from Adenia volkensii Harms (kilyambiti plant), a type 2 ribosome-inactivating protein.

Volkensin, a type 2 ribosome-inactivating protein from the roots of Adenia volkensii Harms (kilyambiti plant) was characterized both at the protein and nucleotide level by direct amino acid sequencing and cloning of the gene encoding the protein. Gene sequence analysis revealed that volkensin is encoded by a 1569-bp ORF (523 amino acid residues) without introns, with an internal linker sequence of 45 bp. Differences in residues present at several sequence positions (reproduced after repeated protein sequence analyses), with respect to the gene sequence, suggest several isoforms for the volkensin A-chain. Based on the crystallographic coordinates of ricin, which shares a high sequence identity with volkensin, a molecular model of volkensin was obtained. The 3D model suggests that the amino acid residues of the active site of the ricin A-chain are conserved at identical spatial positions, including Ser203, a novel amino acid residue found to be conserved in all known ribosome-inactivating proteins. The sugar binding site 1 of the ricin B-chain is also conserved in the volkensin B-chain, whilst in binding site 2, His246 replaces Tyr248. Native volkensin contains two free cysteinyl residues out of 14 derived from the gene sequence, thus suggesting a further disulphide bridge in the B chain, in addition to the inter- and intrachain disulphide bond pattern common to other type 2 ribosome-inactivating proteins.

Amino Acid Sequence↗
PubMed2001

Antibacterial activity of raspberry cordial in vitro.

Raspberry juice cordial has a long anecdotal use in Australia for the prophylaxis and treatment of gastroenteritis in livestock, cage birds and humans. The antimicrobial properties of raspberry juice cordial, raspberry juice, raspberry leaf extract and a commercial brand of raspberry leaf tea were investigated against five human pathogenic bacteria and two fungi. Raspberry cordial and juice were found to significantly reduce the growth of several species of bacteria, including Salmonella, Shigella and E. coli, but demonstrated no antifungal activity. No antimicrobial activity was detected in the leaf extract or tea.

Animals↗