Genetic control of 3-hydroxy- and 3-deoxy- flavonoids in Zea mays

Genetic strains of maize have been derived that have strong concentrations of 3-deoxyanthocyanins, flavan-4-ols and C-glycosyl-flavones in silks and cob. The gene Pr controls the B-ring hydroxylation pattern of both 3-deoxy- and 3-hydroxy-flavonoids in these plants. Cob phlobaphenes are red in Pr plants and orange in pr plants, corresponding to the presence of the probable precursors luteoforol and aniforol.     

The biological basis of epistasis between quantitative trait loci for flavone and 3-deoxyanthocyanin synthesis in maize (Zea mays L.).

A major weakness in our understanding of the genetic basis of complex traits has been that of defining the extent and biological basis of epistasis. Our research group has been studying the genetic control of the accumulation of maysin, a C-glycosyl flavone, in maize, Zea mays (L.), silks. Previously, we demonstrated the importance of the p1 locus as a QTL for maysin synthesis. The p1 locus often exhibits significant epistatic interactions with other loci. We developed a mapping population, (W23al x GT119)F2, specifically designed to test whether genes in an intersecting pathway might be detected as QTLs for maysin synthesis and result in epistatic interaction effects. The a1 gene is not required for the synthesis of flavones but is required for the synthesis of 3-deoxyanthocyanins, an intersecting pathway, in maize silks. The p1 locus (P < 0.0001) was a QTL for both flavones and 3-deoxyanthocyanins. The a1 locus was also highly significant (P < 0.0001) for both traits, as was the p1 x a1 epistatic interaction (P < 0.0001). Our results demonstrate that altering the flux of biochemical intermediates between pathways may be the biological basis of major QTL effects and epistatic interactions.     

Complementary genes control biparental plastid inheritance in Pelargonium

Summary Zonal pelargoniums exhibit biparental plastid inheritance. After G x W plastid crosses the progeny are a mixture of green, variegated and white embryos corresponding to a maternal, biparental or paternal inheritance of plastids, respectively. There are two patterns of segregation: type-I females have families in which the majority of embryos are green, variegated are of intermediate frequency and white are the least frequent. Type-II females have families in which green and white embryos are present at about the same frequency and variegated are the least common. The results of many selfs and crosses made within and between 8 type-I and 8 type-II plants led us to conclude that the type of female was determined by its genotype with respect to a pair of complementary genes. Plants giving rise to the type-II pattern contained one or two copies of the dominant alleles of both genes, whereas in the absence of either one or both dominant alleles the plants were type I. The genes were called Pr1/pr1 and Pr2/pr2, an adaptation of symbolism used previously. All 8 type IIs were double heterozygotes Pr1pr1, Pr2pr2, whereas we found 3 genotypes among the type Is, Pr1Pr1, pr2pr2; pr1pr1, Pr2Pr2 and pr1pr1, Pr2pr2. In unrelated experiments we found type IIs of which some were again double heterozygotes and others single heterozygotes Pr1pr1, Pr2Pr2 or Pr1Pr1, Pr2pr2. The model displaces an earlier model based on the proposed operation of a gametophytic lethal or incompatibility system.     

The genetic basis of C-glycosyl flavone B-ring modification in maize (Zea mays L.) silks.

Resistance to corn earworm (CEW) (Helicoverpa zea Boddie) has been attributed to high concentrations of C-glycosyl flavones and chlorogenic acid in maize (Zea mays L.) silks. The most common C-glycosyl flavones isolated from maize silks are maysin, apimaysin, and methoxymaysin, which are distinguished by their B-ring substitutions. For a better understanding of the genetic mechanisms underlying the synthesis of these compounds, we conducted a quantitative trait locus (QTL) study with two populations: (Tx501 x NC7A)F2 and (Tx501 x Mp708)F2. For chlorogenic acid, maysin, and methoxymaysin concentration, the major QTL for both populations was located on chromosome 4 near umc1963. For apimaysin, the major QTL in both populations was located at the position of the pr1 locus on chromosome 5. The QTL alleles on chromosome 4 that increased the synthesis of methoxymaysin significantly decreased the synthesis of maysin and chlorogenic acid. This decrease in maysin concentration was four-fold greater than the increase in methoxymaysin. Our results indicate that the QTL on chromosome 4, responsible for the increase in methoxymaysin synthesis, alters the dynamics of both the phenylpropanoid and flavonoid pathways.     

Effect of flavonoid pigments on the accumulation of fumonisin B1 in the maize kernel

Mycotoxins are secondary metabolites with potential dangers for animal and human health. In particular, maize (Zea mays L.) infection caused by Fusarium and the consequent fumonisin contamination is widespread in several countries such as Italy. We developed six maize populations differing in their constitution of regulatory genes able to accumulate respectively anthocyanins in the aleurone layer (r1 gene), pericarp (b1 and pl1 genes) and phlobaphene in the pericarp (p1 gene). These coloured populations, with the related control colourless populations were analysed for mycotoxin content in the kernels during three field seasons with the aim of understanding if there were any correlations with their ability to accumulate flavonoids in kernel tissues. Our results indicate that accumulation of flavonoid pigments in the seeds, in particular phlobaphenes, is able to reduce the level of fumonisin B1. This finding could be used to minimize kernel mycotoxin contamination in this crop, in particular, the development of sweet, pop and polenta coloured corn varieties will help the farmer to keep the level of fumonisin under the threshold of contamination established for human corn consumption.     

Neuroprotective effect of Korea Red Ginseng extract on 1-methyl-4-phenylpyridinium-induced apoptosis in PC12 Cells

Background: Korean Red Ginseng (KRG) is a valuable herb in Asian countries that is used as a crude substance to inhibit inflammation and to enhance vitality, longevity and immunity. The protective effects of KRG against the toxicity of 1-methyl-4-phenylpyridinium (MPP+) were investigated in vitro in the present study.

Methods: PC12 cells were pretreated with the water extract of KRG for 24?h, then incubated with MPP+ for 24?h. The growth of the cells was assessed using a live cell viability assay, the ratio of apoptotic cells was measured using flow cytometry and morphology of the apoptotic cells was detected using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining. The expressions of caspase-3 and -9 were measured by quantitative real-time PCR.

Results: Pretreatment of the KRG extract increased cell viability significantly when compared with that of only MPP+-treated cells (p?p?p?p?Conclusion: These results indicate that KRG treatment suppresses MPP+-induced apoptosis in PC12 cells by regulating caspase cascades, suggesting a possible role for KRG in the prevention and treatment of Parkinson’s disease.     

Fatty acids from oleaginous yeasts and yeast-like fungi and their potential applications

Purpose: Oleaginous yeasts, fatty acids biosynthesis and regulation in the oleaginous yeasts and the fatty acids from the oleaginous yeasts and their applications are reviewed in this article.

Results: Oleaginous yeasts such as Rhodosporidium toruloides, Yarrowia lipolytica, Rhodotorula mucilaginosa, and Aureobasidium melanogenum, which can accumulate over 50% lipid of their cell dry weight, have many advantages over other oleaginous microorganisms. The fatty acids from the oleaginous yeasts have many potential applications. Many oleaginous yeasts have now been genetically modified to over-produce fatty acids and their derivatives. The most important features of the oleaginous yeasts are that they have special enzymatic systems for enhanced biosynthesis and regulation of fatty acids in their lipid particles. Recently, some oleaginous yeasts such as R. toruloides have been found to have a unique fatty acids synthetase and other oleaginous yeasts such as A. melanogenum have a unique highly reducing polyketide synthase (HR-PKS) involved in the biosynthesis of hydroxyl fatty acids.

Conclusions: It is necessary to further enhance lipid biosynthesis using metabolic engineering and explore new applications of fatty acids in biotechnology.     

Sleep habits of Iranian pre-school children in an urban area: Late sleeping and sleep debt in children

Using BEARS (Bedtime problems, Excessive sleepiness, Awakenings during the night, Regularity of sleep, Snoring), and CSHQ (Children’s Sleep Habits Questionnaires) screening tools with 224 participants revealed that Iranian children have shorter night sleep duration than expected (9.54 vs 12 h) for their age group. Earlier sleepers had longer night sleep duration (10:36 ± 1:12; 9:12 ± 1:06 h, P > 0.001), and total daily sleep time (11:36 ± 1:42; 10:36 ± 1:30 h, P = 0.005) than late sleepers. A majority (85%) of naptakers had sleep bedtime of 22:00 or later. The poor sleep quality of Iranian preschool children is probably due to cultural characteristics, climate differences, or harmful sleep habits.

     

Interactive effects of chromate and arsenate on their uptake and speciation in Pteris ensiformis

Background and aims

Arsenate (AsV) and chromate (CrVI) inhibit each other’s uptake and translocation in As-hyperaccumulator Pteris vittata. In the present study, we extended the research to As-sensitive plant Pteris ensiformis to better understand the mechanism of their interactions.

Methods

Plants were exposed to 0, 0.75 or 7.5 mg L^?1 AsV and 0, 0.52, or 5.2 mg L^?1 CrVI for 7 d in hydroponics. Arsenic and Cr speciation were determined in nutrient solutions and plant biomass.

Results

P. ensiformis accumulated high levels of As and Cr in the rhizomes and roots with low levels in the fronds. However, P. ensiformis was much more effective in taking up Cr than As, as much more Cr was accumulated in the roots (306–6015 vs. 87–642 mg kg^?1). AsV and CrVI increased each other’s uptake in the rhizomes and roots when co-present. The AsV and CrVI taken up by P. ensiformis were reduced to arsenite (AsIII) and chromite (CrIII), possibly serving as detoxification mechanism.

Conclusions

Uptake of As and Cr induced oxidative stress as indicated by increased lipid peroxidation and electrical conductivity. Arsenic and Cr increased each other’s uptake by P. ensiformis.

     

Three new species of Parhydraenida Balfour-Browne, 1975 (Coleoptera: Hydraenidae) from southeastern Brazil

ABSTRACT

Three new species of Parhydraenida Balfour-Browne, 1975 are described from southeastern Brazil: P. plesioformis, sp. n.; P. proboscis sp. n.; P. unicornis sp. n. The genus Parhydraenida is recorded from Minas Gerais for the first time, and P. hygropetrica Perkins, 1980 is recorded from Rio de Janeiro for the first time. We describe one secondary sexual character, which enables, for the first time, unambiguous distinction of males and females. Habitus photographs as well as line drawings of the male and female genitalia of all three new species, and of P. hygropetrica are provided.

urn:lsid:zoobank.org:pub:CCA56FB6-897A-4128-B8DD-3892464A8D1B     

Biotransformation of heterocyclic dinitriles by Rhodococcus erythropolis and fungal nitrilases

2,6-Pyridinedicarbonitrile (1a) and 2,4-pyridinedicarbonitrile (2a) were hydrated by Rhodococcus erythropolis A4 to 6-cyanopyridine-2-carboxamide (1b; 83% yield) and 2-cyanopyridine-4-carboxamide (2b; 97% yield), respectively, after 10 min. After 118 h, the intermediates 1b or 2b were transformed into 2,6-pyridinedicarboxamide (1c; 35% yield) and 2,6-pyridinedicarboxylic acid (1d; 60% yield) or 2-cyanopyridine-4-carboxylic acid (2c; 64% yield), respectively. The nitrilase from Fusarium solani afforded cyanocarboxylic acids 1e and 2c after 118 h (yields 95 and 62%, respectively). 3,4-Pyridinedicarbonitrile (3a) and 2,3-pyrazinedicarbonitrile (4a) were inferior substrates of nitrile hydratase and nitrilase.