Multiple forms of pectinesterase in limes and oranges

Two forms of pectinesterase, apparently similar in MW but differing in charge and response to cation concentration, have been demonstrated in West Indian limes and Washington Navel oranges, and these enzymes have been purified at least 100-fold. In the orange one pectinesterase is located almost exclusively in the peel while the other is located within the segment covers and juice sacs. The location of the two pectinesterases in lime has not been determined.     

Inhibition of limonoid biosynthesis in leaves of Citrus limon,by triethylamine derivatives

Both 2-(4-ethylphenoxy)triethylamine and 2-(3,4-dimethylphenoxy)triethylamine markedly inhibited the biosynthesis of limonoids in lemon leaves. However     

Nicotine inhibition of carotenoid cyclization in Cucurbita ficifolia cotyledons

Nicotine inhibits carotenoid cyclization in greening cucurbit cotyledons resulting in the accumulation of acyclic and monocyclic carotenes. Chlorophyll synthesis is also inhibited by the alkaloid.     

Plasma Carotenoid Concentrations before and after Supplementation with Astaxanthin in Middle-Aged and Senior Subjects

A randomized, double-blind human trial was conducted to assess the effect on the plasma carotenoid concentration of 4- or 12-week astaxanthin supplementation (1 or 3 mg/d) of 20 Japanese middle-aged and senior subjects. The plasma carotenoid concentration was significantly higher after the astaxanthin supplementation than that before in both the 1 mg/d (10 subjects) and 3 mg/d (10 subjects) groups.     

Fungal lycopene: The biotechnology of its production and prospects for its application in medicine

This article deals with the lycopene of mycelial fungi. It pays special attention to its physical and chemical properties, occurrence in nature, biological functions, and the biotechnology of lycopene production. Data are presented concerning the medically important properties of lycopene and the drug Mycolycopene prepared on its basis. Its prospective use in the therapy of prostate cancers is discussed.     

Alpha-amylase synthesis in wheat kernels as influenced by the seed coat

The effect of seed coat removal on the synthesis of α-amylase isoenzymes in wheat was investigated. The immature wheat endosperm-aleurone (seed coat and embryo detached) produced considerably less α-amylase activity than immature whole or de-embryonated wheat kernels, when incubated under identical conditions of 18.5 C and 99% humidity, in the presence or absence of gibberellic acid (GA₃). The incubated endosperm-aleurone also exhibited unique α-amylase isoenzyme composition when compared to the isoenzyme compositions of incubated whole and de-embryonated immature and mature wheat kernels both in the presence or absence of GA₃. Subsequent studies indicated that the seed coat may contain factor(s) required for normal α-amylase isoenzyme synthesis.     

Carotenoid biosynthesis and the evolution of carotenogenesis genes in rust fungi

Diseases caused by rust fungi pose a significant threat to global plant production. Although carotenoid pigments are produced in spores of nearly all rust species, the corresponding biosynthesis pathway(s) have not been investigated. Here, candidate genes for carotenoid biosynthesis in Puccinia graminis f. sp. tritici (Pgt) were identified, cloned and functionally complemented using specifically engineered strains of Escherichia coli. A part of the carotenoid biosynthesis pathway in rust fungi was elucidated, with only two genes, CrtYB and CrtI, catalysing the reactions from geranyl–geranyl diphosphate (GGPP) to γ-carotene. The CrtYB gene encodes a bi-functional lycopene cyclase/phytoene synthase, which catalyses the condensation of two GGPP into phytoene, as well as the cyclisation of the ψ-end of lycopene to form γ-carotene. The CrtI gene encodes a phytoene desaturase that carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene. The evolution of carotenoid pigmentation in rust fungi, including Pgt, P. graminis avenae, P. graminis secalis (Pgs), P. graminis lolli, P. striiformis f. sp. tritici, P. striiformis f. sp. pseudohordei, P. striiformis f. sp. hordei, the “scabrum” rust (putative hybrids between Pgt and Pgs), P. triticina, and P. hordei, was investigated by phylogenetic analysis. Both CrtYB and CrtI were found to be closely related among rust fungi, other pathogenic fungi, and some aphids. Our results provide a springboard to increase the understanding of the physiological role(s) of carotenoid pigments in rust fungi, to better understand evolution within the Pucciniales, and to develop robust molecular diagnostics for rust fungi.     

Distribution of carotenoids in sub-cellular and sub-plastidic fractions of radish seedlings (Raphanus sativus) grown in the presence of bleaching herbicides

The intracellular and intraplastidic distribution of carotenoids has been investigated in radish seedlings grown in the presence of the herbicides amitrole and SAN 6706. Both herbicides caused bleaching and the plants became deficient in chlorophylls and the usual chloroplast cyclic carotenoids, but accumulated the acyclic carotenoid biosynthetic intermediates 15-cis-phytoene and all-trans-lycopene. In both the untreated and herbicide-treated plants all carotenoids, including phytoene and lycopene, were contained in the plastid. In all cases the normal cyclic carotenoids were located virtually exclusively in the thylakoid or prothylakoid fraction. In amitrole-treated plants, lycopene also was contained only in the thylakoid fraction, whereas phytoene, in these and in SAN 6706-treated plants, was detected in both the thylakoid fraction and an envelope preparation. Possible implications for the biosynthesis of the carotenoids are discussed.     

Pigment synthesis in Cucurbita moschata cotyledons as influenced by CPTA and several inhibitors

2-(4-Chlorophenylthio) triethylamine hydrochloride (CPTA) inducedthe accumulation of a number of carotenes in pumpkin (Cucurbitamoschata) cotyledons, a tissue which does not normally accumulatethese pigments. Lycopene accumulated concomitantly with a decreasein -carotene and ß-carotene. CPTA appeared to inhibitcyclases involved in the synthesis of -carotene and ß-caroteneand to stimulate enzymes involved in lycopene synthesis. Cycloheximidereduced this CPTA induced enzyme synthesis while diphenylaminereduced CPTA induced carotene accumulation. Actinomycin D alonereduced accumulation of carotenes, but it did not affect CPTAinduced carotene accumulation. Rather lutein, violoxanthin andneoxanthin decreased and -carotene and ß-caroteneaccumulated. ¹Present address: Morioka Branch, Vegetable and Ornamental CropsResearch Station, Ministry of Agriculture and Forestry, Shimokuriyagawa,Morioka, Japan. (Received August 12, 1974; )     

Formation of edulinine and furoquinoline alkaloids from quinoline derivatives by cell suspension cultures of Ruta graveolens

The formation of furoquinoline alkaloids and of edulinine, elaborated by cell suspension cultures of Ruta graveolens, was found to occur by way of 4-hydroxy-2-quinolone. Other substrates transformed to furoquinolines included 4-hydroxy- and 4-methoxy-3-(3-methyl-2-butenyl)-2-quinolone, known earlier as natural precursors in studies with whole plants. Involvement of dictamnine as a natural precursor of 8-methoxydictamnine (γ-fagarine) and skimmianine was proved using ¹⁴C-labelled compounds. Edulinine in the cell suspensions was formed from such substrates as 4-hydroxy-N-methyl-2-quinolone, 4-hydroxy-3-(3-methyl-2-butenyl)-N-methyl-2-quinolone and its 4- methyl ether; this is probably the natural biosynthetic sequence. Changes in alkaloid yields were noted upon prolonged subculturing.     

The carotenoid pigments in the juice and flavedo of a mandarin hybrid (Citrus reticulata) cv michal during ripening

The carotenoid pigments ofthe mandarin hybrid (Citrus reticulata) cv Michal, in the juice and flavedo were characterized at three ripening stages, before, during and after colour break. During ripening the characteristic mandarin pattern was formed in the juice, which contained cryptoxanthin as the principal pigment. In the flavedo the chloroplast carotenoid pattern of the green fruit changed into the characteristic pattern of C. reticulata with a high level of citraurin which, together with cryptoxanthin, imparts an intensive reddish tint to the hybrid. The flavedo contained an unusual C₃₀ apocarotenoid, β-citraurinene (8′-apo-β-caroten-3-ol). The flavedo carotenoids of this accidental hybrid were compared with the carotenoids of the presumed parents Dancy tangerine and Clementine. The hybrid resembles more the second parent, from which it inherited the ability to biosynthesize a higher amount of citraurin as well as citraurinene. Citraurinene, considered a Citrus hybrid-specific pigment, was found for the first time in a Citrus variety. A possible biosynthetic pathway of the Citrus C₃₀ -apocarotenoids is proposed.     

Carotenoid composition in sun and shade leaves of plants with different life forms

The carotenoid composition of sun leaves of nine species of annual crop plants (some with several varieties) was compared with sun and shade leaves of several other groups of plants, among those sun and shade leaves of several species of perennial shrubs and vines and deep-shade leaves of seven rainforest species. All sun leaves contained considerably greater amounts of the components of the xanthophyll cycle violaxanthin, antheraxanthin and zeaxanthin as well as of β-carotene than the shade leaves, as had previously been reported for a variety of other species by Thayer & Björkman (Photosynthesis Research, 1990, 23, 331–343). Therefore, high light specifically stimulated β,β-carotenoid synthesis. The sun leaves of these crop species did not contain α-carotene which was, however, present in large amounts in all shade leaves and in smaller amounts in sun leaves of three of the four species of perennial shrubs and vines. There was no difference in neoxanthin content on a chlorophyll basis between sun and shade leaves, and there was no consistent general difference in the lutein content between all sun and all shade leaves. The zeaxanthin (and antheraxanthin) content at peak irradiance and the xanthophyll cycle pool size were compared for sun leaves from the different groups of plants with different life forms and different metabolic activities. When growing in full sunlight the annual crop species and a perennial mesophyte had high rates of photosynthesis whereas the perennial shrubs and vines had relatively low photosynthesis rates. More zeaxanthin (and antheraxanthin) were accumulated at noon in full sunlight in those species with the lower photosynthesis rates. However, it was not such that those species also possessed the larger pools of violaxanthin + antheraxanthin + zeaxanthin. Instead, the xanthophyll cycle pools of sun leaves of the annual crop species and the perennial mesophyte were not smaller, and were even possibly larger, than those of sun leaves of the perennial shrubs and vines with low photosynthesis rates. This was so in spite of the fact that the crop species experienced much lesser degrees of excessive light at full sun than the shrubs and vines. Thus, many of the crop species converted only about 30–50% of their xanthophyll cycle pool to zeaxanthin at noon, whereas the shrubs and vines typically converted more than 80% of their pool into zeaxanthin. The crop species also had larger pools of β-carotene than the shrubs and vines but smaller pools of lutein than the majority of the latter species.     

Gravitropic response of primary maize rootlets as influenced by light and temperature

Abstract. The gravitropic curvature of primary maize rootlets was measured as a function of temperature, both in the presence and absence of light. In two different cultivars, light strongly increased the downward curvature of roots developing from horizontally-oriented embryos. At 15–20°C, the bending angle was in the range of 70–80° in the light, and 25–50° in the dark, depending on the cultivar. When the temperature was increased above the 15–20°C range, marked differences were found between the two cultivars in their response to light. In one variety tested, JX180, the effect of light was relatively small at 30–35°C. Gravitropic curvature in another variety, Halamish, depended strongly on light throughout the temperature range tested. In both cultivars, gravitropic curvature was only slightly temperature dependent when germination and growth were in total darkness. In the dark, the extent of gravitropic curvature also depended on whether the kernels were oriented with their embryos facing upwards or downwards. Under continuous light, the gravitropic bending of roots of cultivar Halamish did not show a marked temperature dependence. When the seedlings were subjected to only a 15 min illumination, their gravitropic response was partial, and the dependence on temperature somewhat increased. In cultivar JX180, a combination of temperature and light modulates gravitropism. The gravitropic response of different maize cultivars thus differs considerably in its combined dependence on light and temperature.     

Carotenoid trade-off between parasitic resistance and sexual display: an experimental study in the blackbird (Turdus merula)

Many parasites depress the expression of the carotenoid-based colour displays of their hosts, and it has been hypothesized that animals face a trade-off in carotenoid allocation between immune functions and 'degree of ornamentation'. While numerous correlative studies suggest that parasite infection decreases the intensity of carotenoid-based colour displays, the existence of this trade-off has never been demonstrated experimentally in a host-parasite model. In this study, we used the blackbird (Turdus merula) and Isospora (an intestinal parasite) to assess whether this trade-off does indeed exist. Blackbirds were supplemented with carotenoids while simultaneously being exposed to parasites. Supplemented males circulated more carotenoids in the blood and developed more brightly coloured bills than unsupplemented males. In addition, supplementation slowed down the replication rate of parasites. Supplementation with carotenoids enabled infected birds to maintain their bill coloration, whereas birds that were infected but not supplemented showed reduced bill coloration. At the same time, infection slowed carotenoid assimilation in the blood. Overall, we demonstrated that bill colour reflects a bird's health, and that only males with a carotenoid-rich diet are capable of coping with costs associated with parasitic infection. Carotenoids are thus traded off between host physiological response to parasites and secondary sexual traits. Further investigations are required to determine the physiological mechanisms that govern this trade-off.     

Synthetic regulators of carotenoid biosynthesis in Citrus paradisi

The ability of 16 amines to induce carotenoid biosynthesis in Marsh seedless grapefruit is correlated with the octanol-water partition coefficient and the Hammett constants. The compounds fall into three series: p-RC₆H₄COOCH₂CH₂NEt₂ (R = H, NH₂, CN, NO₂, MeO, Me, tert-Bu, F, Cl, Br), p-RC₆H₄CH₂NEt₂ (R = H, Me, NO₂), and RC₆H₄OCH₂CH₂NEt₂ (R = o-Me, m-Me, p-Me). Total carotene content increased up to 12-fold. Lycopene, not normally accumulated, became a major pigment. The benzoates caused up to a 24-fold increase in the β-carotene content. Except for the larger accumulation of cyclic carotenes, the mode of action of these amines appears to be similar to that of 2-(4-chlorophenylthio triethylamine hydrochloride.     

Structure and synthesis of atalaphylline and related alkaloids

The structure of atalaphylline, (1; 1,3,5-trihydroxy-4-(γ,γ-dimethylallyl)acridone an alkaloid of Atalantia monophylla, was confirmed by oxidative degradation and by total synthesis. The synthesis involved the preparation of 1,3,5-trihydroxy-9-acridone followed by direct prenylation to give atalaphylline and a monoprenylated product.     

Water quality and soil properties of ponds as influenced by Makhana (Euryale ferox) cultivation

Summary Analysis of regularly collected samples of soil and water from Makhana (Euryale ferox) growing ponds indicated that pH of soil and water were established near neutrality and C/N of soil near ten. Bicarbonate dominated soil extract while chloride dominated standing water. During grand growth period (March to June), Ca²⁺+Mg²⁺, NH ₄ ⁺ K⁺ increased while Na⁺ increased during decay of the plant (July to September) both in soil and plants. The soil had high contents of micro-nutrients, K and P. S.A.R. of soil was 3 to 4 times that of water. Free energy of exchange indicated stability and spontaneity.