Oxidation of zeaxanthin: Isolation and properties of 3-hydroxyretinene

1. Anthers of Delonix regia flowers are a rich source of zeaxanthin. 2. Oxidation of zeaxanthin with hydrogen peroxide in the presence of osmium tetroxide results in the formation of 3-hydroxyretinene as one of the products. 3. 3-Hydroxyretinene gives 3-acetoxyretinene with acetic anhydride, and an oxime with hydroxylamine hydrochloride. 4. Reduction of 3-hydroxyretinene with sodium borohydride yields 3-hydroxyvitamin A. 5. Treatment of 3-hydroxyvitamin A with dry ethanolic hydrogen chloride results in the formation of 3-ethoxyanhydrovitamin A (anhydrovitamin A₂) and a compound that resembles naturally occurring anhydrovitamin A₂.     

Preparation of retinamides by use of retinoyl fluoride

Retinoyl fluoride (2) prepared from retinoic acid (1) by reaction with diethylaminosulfurtrifluoride is a stable crystalline compound not easily hydrolyzed by water. By reacting retinoyl fluoride with water-soluble amines in the presence of sodium bicarbonate, retinamide (4), N-retinoyl glycine (6), N-retinoyl DL-phenylalanine (7), alpha-N-retinoyl-L-lysine (11), N-retinoyl 4-aminophenol (4-hydroxyphenylretinamide) (8), and N-retinoyl-2-amino-2-deoxy-D-glucose (2-deoxy-D-glucose-2-retinamide) (9) have been prepared in good yields and characterized by UV absorption, 1H NMR, IR spectra, mass spectrometry, and elemental analysis.     

Heterogeneity of phenotypic and genotypic traits including organic-acid resistance in Escherichia coli O157 isolates

We undertook an epidemiologic study for the sensitivity of both Shiga-like toxin (Slt)-producing Escherichia coli (STEC) O157 and non-STEC O157 strains isolated from different patients with diarrhea to hydrochloric acid (HCl) and organic acids such as acetate, propionate, butyrate and lactate, and other pathogenic factors. The E. coli O157 isolates examined showed a wide variety of organic-acid susceptibility patterns. E. coli O157 isolates resistant to HCl or acetate were found more frequently than those resistant to other organic acids. These isolates also showed diverse pathogenicity patterns for the presence of the virulence genes, antibiotic susceptibility and plasmid profile.     

Bioluminescence emissions of the firefly <Emphasis Type="Italic">Luciola praeusta</Emphasis> Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae)

We recorded the in vivo emission and time-resolved spectra of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae). The emission spectrum shows that the full width at half maximum (FWHM) value for this particular species is 55 nm, which is significantly narrower than the in vivo half-widths reported till now. The time-resolved spectrum reveals that a flash of about 100 ms duration is, in fact, composed of a number of microsecond pulses. This suggests that the speed of the enzyme-catalysed chemiluminescence reaction in the firefly for the emission of light is much faster than was previously believed. A version of this article has already appeared in an archive Nature Precedings; see     

High herkogamy but low reciprocity characterizes isoplethic populations of Jasminum malabaricum,a species with stigma‐height dimorphism

• Studies of floral polymorphisms have focused on heterostyly, while stigma‐height dimorphism has received considerably less attention. Few studies have examined the reproductive biology of species with stigma‐height dimorphism to understand how factors influencing mate availability and pollen transfer are related to morph ratios in populations.
• Floral morphological traits, especially herkogamy and reciprocity, pollinator visitation, breeding system and spatiotemporal mate availability, are known to affect inter‐morph pollination and morph ratios in species with stigma‐height dimorphism. In this study, we investigated the presence of stigma‐height dimorphism and estimated morph ratios in four naturally occurring populations of Jasminum malabaricum. We quantified morph‐ and population‐specific differences in the abovementioned factors in these populations to understand the observed morph ratios.
• The positions of anthers and stigmas were characteristic of stigma‐height dimorphism, the first report of this polymorphism in the genus. All study populations were isoplethic, implying equal fitness of both morphs. Herkogamy was higher in the short‐styled morph, while reciprocity was higher between the long‐styled stigma and short‐styled anthers. Long‐ and short‐tongued pollinators were common floral visitors, and we observed no differences between morphs in spatiotemporal mate availability or pollinator visitation. Neither morph exhibited self‐ or heteromorphic incompatibility.
• The short‐styled stigma had lower reciprocity but likely receives sufficient inter‐morph pollen from long‐tongued pollinators, and also by avoiding self‐pollination due to higher herkogamy. These results highlight the importance of sufficient effective pollinators and floral morphological features, particularly herkogamy, in maintaining isoplethy in species with stigma‐height dimorphism.

     

Chemical synthesis of all-trans-[11-3H]retinoyl beta-glucuronide and its metabolism in rats in vivo.

All-trans-[11-3H]retinoyl beta-glucuronide (RAG) was synthesized in a single step from all-trans-[11-3H]retinoyl fluoride, with a 24% yield. After its intraperitoneal injection into rats, RAG was detected in the blood, liver, intestine and kidney during the following 24 h period. Although the concentration of radiolabelled metabolites decreased with time, RAG predominated at nearly all times in nearly all tissues. Small amounts of retinoic acid (RA) were also universally present, together with unidentified polar metabolites and small amounts of non-polar esters of RA. The major excretion products of RAG in faeces and urine were RA and polar metabolites. Thus RAG, although converted in part to RA in vivo, persists as a major component in blood and tissues for at least 24 h. These observations support the concept that the retinoid beta-glucuronides might serve a physiologically significant role in the function of vitamin A.     

The effects of age and sex steroids on the macrophage population in the ovary of the chicken, Gallus domesticus

The role of macrophages in the function of the hen ovary has not yet been described, although these cells may be an important regulator of ovarian function in mammals. The aim of this study was to determine the changes in the frequency of macrophages during ageing and follicular atresia, and the effects of sex steroids on the macrophage population in the hen ovary. Cryostat sections of ovarian tissues of immature, young laying and old laying hens and those of immature hens treated with or without diethylstilboestrol (DES) or progesterone were immunostained for macrophage cells using mouse anti-chicken macrophage monoclonal antibody. Macrophages were observed under a light microscope and counted using a computer assisted image analyser. The frequency of macrophages in both the stroma and theca of primary follicles was significantly greater in young laying hens than in immature and old laying hens and these cells were more frequent in old laying hens than in immature hens (P < 0.01). Macrophages were more frequent in atretic follicles than in normal follicles (P < 0.01). The number of macrophages in both the stroma and theca of primary follicles of DES-treated birds was significantly greater than in those of progesterone-treated and control birds (P < 0.01). Progesterone had no significant effect on the population of macrophages. These results suggest that macrophages in the ovary increase in association with sexual maturation of birds and atresia of follicles and decrease during ageing. Oestrogen may be one of the factors that affect the population of macrophages in the hen ovary.