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PubMedDate not supplied

An optimized method for mycelial compatibility testing in Sclerotinia sclerotiorum.

Classification of isolates into mycelial compatibility groups (MCGs) is used routinely in many laboratories as a quick marker for genotyping Sclerotinia sclerotiorum within populations. Scoring each new sample requires optimization of standardized conditions to support adequate growth of all paired isolates. Appropriate conditions for growth are especially important because diverse compatibility reactions are difficult to categorize and score (e.g., in samples from populations with high genetic diversity, such as those that receive immigration from genetically diverse sources or those that deviate from strict clonality). The current standard medium for MCG testing can be inhibitory to isolates from some samples, confounding scoring of compatibility. We identified two foci for optimization: (i) choice of medium, in this experiment, Patterson's medium amended with red food coloring (termed modified Patterson's medium, MPM, the current standard medium) versus potato dextrose agar (PDA) and (ii) amount of McCormick's red food coloring amended to the growth medium. The red food coloring often yields a red reaction line in incompatible interactions; alternative incompatible reactions are a line of thick or thin hyphae. Based on results to date, self-self pairings of S. sclerotiorum are compatible and are a reliable standard for scoring compatible self-nonself mycelial interactions. PDA amended with 75 microl/L of McCormick's red food coloring was identified as optimal for isolates inhibited by MPM from a highly diverse, recombining population sample. This precisely amended PDA was also suitable for isolates from highly clonal populations that were not inhibited by MPM or by higher concentrations of red food coloring. Under the optimized, standardized conditions all paired isolates grew together and produced interactions that could be scored in repeatedly identifiable categories, compatible or incompatible. Workers are advised to optimize conditions before screening a new population sample.

Ascomycota↗
PubMed2000

Development of a chromosome-plasmid balanced lethal system for Lactobacillus acidophilus with thyA gene as selective marker.

A chromosome-plasmid balanced lethal gene delivery system for Lactobacillus acidophilus based on the thyA gene was developed. The selected L. acidophilus DOM La strain carries a mutated thyA gene and has an obligate requirement for thymidine. This strain can be used as a host for the constructed shuttle vector pFXL03, lacking antibiotic-resistant markers but having the wild-type thyA gene from L. casei which complements the thyA chromosomal mutation. The vector also contains the replicon region from plasmid pUC19 and that of the Lactococcus plasmid pWV01, which allows the transfer between Escherichia coli, L. casei and L. acidophilus. Eight unique restriction sites (i.e., PstI, HindIII, SphI, SalI, AccI, XbaI, KpnI and SacI) are available for cloning. After 40-time transfers in modified MRS medium, no plasmid loss was observed. The vector pFXL03 is potentially useful as a food-grade vaccine delivery system for L. acidophilus.

Drug Delivery Systems↗
PubMed2006

Application of two-dimensional gel electrophoresis to interrogate alterations in the proteome of gentically modified crops. 3. Assessing unintended effects.

The current procedures to assess the safety of food and feed derived from modern biotechnology include the investigation of possible unintended effects. To improve the probability of detecting unintended effects, profiling techniques such as proteomics are currently tested as complementary analytical tools to the existing safety assessment. An optimized two-dimensional gel electrophoresis (2DE) method was used as a proteomics approach to investigate insertional and pleiotropic effects on the proteome due to genetic engineering. Twelve transgenic Arabidopsis thaliana lines were analyzed by 2DE, and their seed proteomes were compared to that of their parental line as well as to 12 Arabidopsis ecotype lines. The genetic modification of the Arabidopsis lines, using three different genes and three different promoters, did not cause unintended changes to the analyzed seed proteome. Differences in spot quantity between transgenic and nontransgenic lines fell in the range of values found in the 12 Arabidopsis ecotype lines or were related to the introduced gene.

Arabidopsis↗
PubMed2003

Modification of plant lipids for human health: development of functional land-based omega-3 fatty acids.

We have remodeled canola seeds to accumulate the omega-3 fatty acid, stearidonic acid (SDA). In doing so, we have demonstrated the feasibility of developing a land-based source of functional omega-3 fatty acids on a large scale. Land-based omega-3 fatty acids represent a sustainable source of omega-3 fatty acids that can be produced on large acreages and delivered to consumers in a wide variety of functional foods. And unlike alpha-linolenic acid, SDA can provide eicosapentaenoic acid equivalence at moderate intakes. Widely applied, SDA-enriched foods could become a valuable tool for delivering recommended levels of omega-3 fatty acids to large portions of the population. By obviating the need for dietary changes, SDA-enriched foods may facilitate increased compliance with recommendations for daily omega-3 intakes.

Biotechnology↗
PubMed1993

Zinc status in pregnancy: the effect of zinc therapy on perinatal mortality, prematurity, and placental ablation.

Zinc is present in and indispensable to all forms of life. Zinc is essential for the normal growth of human beings, and zinc proteins have been shown to be involved in the transcription and translation of the genetic material. Zinc deficiency has been incriminated in infertility, abortions, malformations, fetal intrauterine growth retardation, premature and postmature births, perinatal death, and abnormal deliveries with dystocia and placental ablation. Risk groups for developing zinc deficiency, which in turn might modify the expression of the underlying disease, are found among those with insufficient food intake, especially in protein malnutrition; abnormal mucosal uptake, as in celiac disease; abnormal intestinal losses, as in steatorrhea and inflammatory bowel disease; abnormal renal excretion, as in diabetes with insufficient metabolic control; alcoholism; and treatment with diuretic drugs. Zinc deficiency could be identified by means of fasting serum or plasma samples or the more laborious estimation of zinc in leucocytes or monocytes if sampling and handling is carefully performed and if stressful situations and acute-phase reactions as fever, delivery, or abortion are avoided. Zinc therapy in identified low-zinc groups has given favorable results and has reduced the frequencies of premature birth, placental ablation, perinatal death, and postmaturity. It is suggested, as we did in 1980, that these data are compatible with the presence of a zinc-deficiency syndrome in pregnancy, which includes increased maternal morbidity, abnormal taste sensations, abnormally short or prolonged gestations, inefficient labor, atonic bleeding, and increased risks to the fetus such as malformations, growth retardation, prematurity, postmaturity, and perinatal death.

Female↗
PubMed1998

[Changes in female reproduction induced by ammonium metavanadate in Swiss albino mice].

Female reproduction alterations induced by vanadium salts, taken in periods no related with mating/gestation, correlated with histological alterations has not been reported. Vanadium is a metal from VB group of periodical table, and it has been detected in high concentrations in heavy petroleum produced in this region of our country, there have not had investigations about vanadium effect on species reproduction. In this work 100 and 200 ppm doses of ammonium vanadate (A.M.V.) prepared with demineralized water were administered orally to swiss albino mice in different periods. The administration of vanadium salt was suspended before mating. Pregnant mice were allowed to deliver and a statistical analysis were performed to pregnancy percent and pups means. Non pregnant mice were killed after 21 days of mating. Uterus and ovaries were weight, luteal bodies were counted and histological samples of ovaries were prepared. The results shown a non significative increase of pregnancy (p < 1) in mice exposed from weaning to adult, for animals exposed to maximum concentrations 200 ppm a significative reduction of pregnancy (p = 0.00001), to mean pups were detected (z = 0.68), and number of luteal bodies (s = 3.3 +/- 0.5). The microscopic observation shown polycystic ovary, atresic follicular increasing, follicle in mature stage and luteal bodies; hard decreasing; hard depletion was observed in thecoluteic cells of luteal bodies. A.M.V. modify reproduction even though if exposition have been made in period before mating and pregnancy. As doses and exposition periods increase detrimental effects induces alteration in the follicular phase and luteal of ovarian cycle. Epidemiological and genetic studies are recommended in regions where vanadium concentrations are high, and the drinking water and foods are contaminated with this metal, in order to know how it affect human reproduction.

Administration, Oral↗
PubMed2002

Expression of an antisense GIGANTEA (GI) gene fragment in transgenic radish causes delayed bolting and flowering.

A late-flowering transgenic radish has been produced by the expression of an antisense GIGANTEA (GI) gene fragment using a floral-dip method. Twenty-five plants were dipped into a suspension of Agrobacterium carrying a 2.5 kb antisense GI gene fragment from Arabidopsis, along with the gusA and bar reporter genes, all under the control of a CaMV 35S promoter. From a total of 1462 seeds harvested from these floral-dipped plants, 16 Basta-resistant T1 plants were found to have GUS activity (transformation efficiency of 1.1%). Southern analysis confirmed the integration of one or two copies of the gusA gene in these herbicide-resistant plants. Expression of the GI gene in T1 plants was much reduced compared to both wildtype plants and plants transformed with pCAMBIA3301 (positive control). In the progenies of eleven T1 plants analysed (T2 generation), all lines showed a significant delay in both bolting and flowering times compared to wildtype and positive control plants, and that, the level of GI transcript was inversely proportional to the time of bolting and flowering. At a maximum, bolting and flowering times were delayed by 17 and 18 days respectively, compared to wildtype plants (in positive control plants, the delay was 23 and 26 days, respectively). Ten of the 11 lines exhibited a significant reduction in plant height compared to wildtype and positive control plants. This study provides evidence that down-regulation of the GI gene by co-suppression could delay bolting in a cold-sensitive long-day (LD) plant. Production of late-flowering germplasms of radish may allow this important crop to be cultivated over an extended period and also provide further food to the famine countries of S/E Asia.

Agrobacterium tumefaciens↗
PubMed2004

Microsatellite PCR profiling of Saccharomyces cerevisiae strains during wine fermentation.

AIMS: Use of microsatellite PCR to monitor populations of Saccharomyces cerevisiae strains during fermentation of grape juice. METHOD AND RESULTS: Six commercial wine strains of S. cerevisiae were screened for polymorphism at the SC8132X locus using a modified rapid PCR identification technique. The strains formed four distinct polymorphic groups that could be readily distinguished from one another. Fermentations inoculated with mixtures of three strains polymorphic at the SC8132X locus were monitored until sugar utilization was complete, and all exhibited a changing population structure throughout the fermentation. CONCLUSIONS: Rapid population quantification demonstrated that wine fermentations are dynamic and do not necessarily reflect the initial yeast population structure. One or more yeast strains were found to dominate at different stages of the fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: The population structure of S. cerevisiae during mixed culture wine fermentation is dynamic and could modify the chemical composition and flavour profile of wine.

Carbohydrate Metabolism↗
PubMed1999

Agricultural approaches to improving phytonutrient content in plants: an overview.

Recent advances in plant molecular biology, functional genomics, and biochemistry have opened up a number of new avenues of research that will enable plant biologists to characterize, increase and modify plant content of a wide range of essential minerals and vitamins, as well as a number of secondary plant compounds that appear to play a role in improving human health and nutrition. In this review, several examples of exciting new research applying plant genomic and molecular genetic approaches to the improvement of phytonutrient content and composition in plants are presented. Research focusing on the elucidation of many of these complex biosynthetic and transport pathways in plants will require considerable resources in terms of funding, time, and personnel. As plant biologists move into interdisciplinary collaborations with nutritionists and food scientists, attention must be paid to a more complete identification and characterization of specific bioactive phytonutrients. Also, a more detailed assessment of the health-promoting properties of these compounds is needed, particularly for many of the secondary plant compounds for which clear epidemiologic and clinical data are still lacking. Finally, in order for significant progress to be made in modifying the nutrient composition of crops, a major investment must be made by funding agencies.

Agriculture↗
PubMed2004

The ecological genetics of conditional strategies.

We develop a quantitative genetic model for conditional strategies that incorporates the ecological realism of previous strategic models. Similar to strategic models, the results show that environmental heterogeneity, cue reliability, and environment-dependent fitness trade-offs for the alternative tactics of the conditional strategy interact to determine when conditional strategies will be favored and that conditional strategies should be a common form of adaptive variation in nature. The results also show that conditional and unconditional development can be maintained in one of two ways: by frequency-dependent selection or by the maintenance of genetic variation that exceeds the threshold for induction. We then modified the model to take into account variance in exposures to the environmental cue as well as variance in response to the cue, which allows a derivation of a dose-response curve. Here the results showed that increasing the genetic variance for response both flattens and shifts the dose-response curve. Finally, we modify the model to derive the dose-response curve for a population polymorphic for a gene that blocks expression of the conditional strategy. We illustrate the utility of the model by application to predator-induced defense in an intertidal barnacle and compare the results with phenotypic models of selection.

Adaptation, Physiological↗
PubMed2004

[Advances in research on biosynthesis of plant amylopectin].

Amylopectin, accounting for 70%-80% of storage starch, is one of the key components for quality of fruits and seeds in plant. Research on biosynthetic pathway of plant amylopectin holds great promise for modifying the structural composition of amylopectin and being used in food industry. The structure of plant amylopectin is summarized in this review and three types of amylopectin synthetase: starch branching enzyme (SBE), soluble starch synthase (SSS) and starch debranching enzyme (SDBE), which have become hotspots for research now, are expatiated in terms of genetics, enzymology and function. A model for the synthesis of amylopectin, "two-step branching and improper branch clearing model" is discussed. Problems in plant amylopectin biosynthesis and prospects for its application are also presented.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1996

Genetics of subtilin and nisin biosyntheses: biosynthesis of lantibiotics.

Several peptide antibiotics have been described as potent inhibitors of bacterial growth. With respect to their biosynthesis, they can be divided into two classes: (i) those that are synthesized by a non-ribosomal mechanism, and (ii) those that are ribosomally synthesized. Subtilin and nisin belong to the ribosomally synthesized peptide antibiotics. They contain the rare amino acids dehydroalanine, dehydrobutyrine, meso-lanthionine, and 3-methyllanthionine. They are derived from prepeptides which are post-translationally modified and have been termed lantibiotics because of their characteristic lanthionine bridges (Schnell et al. 1988). Nisin is the most prominent lantibiotic and is used as a food preservative due to its high potency against certain gram-positive bacteria (Mattick & Hirsch 1944, 1947; Rayman & Hurst 1984). It is produced by Lactococcus lactis strains belonging to serological group N. The potent bactericidal activities of nisin and other lantibiotics are based on depolarization of energized bacterial cytoplasmic membranes. Breakdown of the membrane potential is initiated by the formation of pores through which molecules of low molecular weight are released. A trans-negative membrane potential of 50 to 100 mV is necessary for pore formation by nisin (Ruhr & Sahl 1985; Sahl et al. 1987). Nisin occurs as a partially amphiphilic molecule (Van de Ven et al. 1991). Apart from the detergent-like effect of nisin on cytoplasmic membranes, an inhibition of murein synthesis has also been discussed as the primary effect (Reisinger et al. 1980). In several countries nisin is used to prevent the growth of clostridia in cheese and canned food. The nisin peptide structure was first described by Gross & Morall (1971), and its structural gene was isolated in 1988 (Buchman et al. 1988; Kaletta & Entian 1989). Nisin has two natural variants, nisin A, and nisin Z, which differ in a single amino acid residue at position 27 (histidin in nisin A is replaced by asparagin in nisin Z (Mulders et al. 1991; De Vos et al. 1993). Subtilin is produced by Bacillus subtilis ATCC 6633. Its chemical structure was first unravelled by Gross & Kiltz (1973) and its structural gene was isolated in 1988 (Banerjee & Hansen 1988). Subtilin shares strong similarities to nisin with an identical organization of the lanthionine ring structures (Fig. 1), and both lantibiotics possess similar antibiotic activities. Due to its easy genetic analysis B. subtilis became a very suitable model organism for the identification and characterization of genes and proteins involved in lantibiotic biosynthesis. The pathway by which nisin is produced is very similar to that of subtilin, and the proteins involved share significant homologies over the entire proteins (for review see also De Vos et al. 1995b). The respective genes have been identified adjacent to the structural genes, and are organized in operon-like structures (Fig. 2). These genes are responsible for post-translational modification, transport of the modified prepeptide, proteolytic cleavage, and immunity which prevents toxic effects on the producing bacterium. In addition to this, biosynthesis of subtilin and nisin is strongly regulated by a two-component regulatory system which consists of a histidin kinase and a response regulator protein.

Amino Acid Sequence↗
PubMed2005

The canine model of dietary hypersensitivity.

IgE-mediated dietary hypersensitivity affects approximately 1% of the canine population. There are no breed associations and < or =50% of the patients are aged <1 year at presentation. The most common causative allergens are beef, chicken, milk, eggs, maize, wheat and soyabean. Affected dogs generally display cutaneous disease and 10-15% of the patients may have concurrent alimentary involvement. Diagnosis is currently based on dietary restriction followed by provocation. Procedures for the detection of serum allergen-specific IgE and IgG antibodies are widely available, but these tests correlate poorly with clinical presentation and dietary testing. Recent studies have demonstrated the allergen specificity of IgE antibodies by immunoblotting and have described blood lymphocyte proliferative responses to food allergens. In addition to investigations of spontaneously-arising dietary hypersensitivity, it has also proved possible to study this disorder experimentally. Small colonies of dogs sensitive to particular dietary proteins have been used to study clinical and serological responses to allergen challenge. Hypersensitivity has been experimentally induced in dogs of an atopic phenotype by repeated subcutaneous injection of alum-adjuvanted dietary allergen during neonatal life. These models have been used to trial a range of modified protein or hydrolysate diets. The dog provides a unique large-animal model for investigation of the immunopathogenesis of human dietary hypersensitivity. The dog is closely related genetically to man and shares environmental disease triggers with man. Spontaneously arising canine dietary hypersensitivity is a good clinical mimic of the human disease, and ability to therapeutically manipulate this adverse response in the dog might lead to benefits for human patients.

Allergens↗
PubMed1997

Stimulation of tachykinin NK-3 receptors in the nucleus basalis magnocellularis reduces alcohol intake in rats.

Injections in the nucleus basalis magnocellularis (NBM) of the tachykinin (TK) NK-3 receptor agonist [Asp5,6,MePhe8]substance P(5-11), also referred to as amino-senktide (NH2-SENK), markedly reduced alcohol intake in genetically selected alcohol-preferring rats, offered 10% ethanol 2 h/day. The threshold dose in the NBM was 0.5 ng/site, while neither 1 nor 10 ng/rat of NH2-SENK inhibited alcohol intake following administration into the lateral ventricle. Injection of NH2-SENK, 25 ng/site, in the NBM did not modify water or food intake in water deprived rats, providing evidence for the behavioral selectivity of the effect on ethanol intake. The selective TK NK-3 receptor antagonist, R-820, injected in the NBM at the dose of 1000 ng/site 5 min before NH2-SENK 5 ng/site, significantly reduced the effect of NH2-SENK. The selective TK NK-1 receptor agonist [Sar9,Met(O2)11]substance P inhibited alcohol intake following injection in the NBM only at 25 ng/site; but the same dose induced marked grooming and inhibited also water intake in water deprived rats. The present results confirm that TK NK-3, but not NK-1, receptor agonists selectively inhibit ethanol intake in alcohol-preferring rats and suggest that the NBM is a site of action for their effect.

Alcohol Drinking↗
PubMed2002

The risk of breast cancer associated with dietary lignans differs by CYP17 genotype in women.

Lignans are plant compounds metabolized in the gut to produce the phytoestrogens enterolactone and enterodiol. Reduced breast cancer risks associated with higher urinary lignan excretion may be related to competitive inhibition of endogenous estrogens. Evidence exists that associations with reproductive risk factors for breast cancer differ according to cytochrome P450c17alpha (CYP17) genotype. Genetic variability in estrogen metabolism could affect lignan metabolism thereby modifying risk associations. We examined breast cancer risk, dietary lignans and CYP17 genotype among 207 women with primary, incident, histologically confirmed breast cancer and 188 controls frequency matched to cases by age and county of residence. Self-reported frequency of intake of 170 foods and beverages during the 2 y before the interview and other relevant data were collected by detailed in-person interviews. Dietary lignan intake was expressed as the sum of enterolactone and enterodiol production from foods. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression, adjusting for age, education and other breast cancer risk factors. Women in the highest tertile of dietary lignans tended to have reduced breast cancer risk (OR 0.45, 95% CI 0.20-1.01 and OR 0.59, 95% CI 0.28-1.27, pre- and postmenopausal women, respectively). Substantially reduced risks in the highest tertile of lignans were observed for premenopausal women with at least one A2 allele (OR 0.12, 95% CI 0.03-0.50). Our results suggest that CYP17 genotype may be important in modifying the effect on breast cancer risk of exogenous estrogens, particularly for premenopausal women.

4-Butyrolactone↗
PubMed2000

Dietary fat intake and regulation of energy balance: implications for obesity.

Obesity represents a major threat to health and quality of life. Although obesity has strong genetic determinants, the increasing prevalence of obesity in populations around the world suggests that environmental factors are promoting or exacerbating the problem. Experts are calling for public health efforts to deal with the global epidemic of obesity. Such a campaign would require that we identify and modify environmental factors that promote obesity. Our current food supply is high in fat, and high fat diets have been suggested to promote obesity by increasing energy intake, thus increasing the probability of positive energy balance and weight gain. However, others argue that high fat diets are not promoting obesity. In this paper, we review evidence from animal studies, carefully controlled laboratory studies, cross-sectional studies, clinical trials and studies in individuals at high risk to develop obesity. Although there are many environmental factors promoting excess energy intake and discouraging energy expenditure, it is clear that consumption of a high fat diet increases the likelihood of obesity and that the risk of obesity is low in individuals consuming low fat diets. On the basis of the available data, the current public health recommendations to lower dietary fat intake appear to be appropriate.

Animals↗
PubMed2006

Olfactory conditioning of proboscis activity in Drosophila melanogaster.

Olfactory learning and memory processes in Drosophila have been well investigated with aversive conditioning, but appetitive conditioning has rarely been documented. Here, we report for the first time individual olfactory conditioning of proboscis activity in restrained Drosophila melanogaster. The protocol was adapted from those developed for proboscis extension conditioning in the honeybee Apis mellifera. After establishing a scale of small proboscis movements necessary to characterize responses to olfactory stimulation, we applied Pavlovian conditioning, with five trials consisting of paired presentation of a banana odour and a sucrose reward. Drosophila showed conditioned proboscis activity to the odour, with a twofold increase of percentage of responses after the first trial. No change occurred in flies experiencing unpaired presentations of the stimuli, confirming an associative basis for this form of olfactory learning. The adenylyl cyclase mutant rutabaga did not exhibit learning in this paradigm. This protocol generated at least a short-term memory of 15 min, but no significant associative memory was detected at 1 h. We also showed that learning performance was dependent on food motivation, by comparing flies subjected to different starvation regimes.

Adenylyl Cyclases↗