Chemical syntheses of novel fluorescent-labelled fatty acids, phosphatidylcholines and cholesterol esters.

The synthesis of a novel class of fluorescent-labelled fatty acids of different chain lengths and unsaturation, phospholipids and cholesterol esters has been developed. The following omega-anthracene-labelled cis-unsaturated fatty acids have been synthesized: omega-(9-anthryl)-6c-octenoic, -7c-nonenoic, -10c-dodecenoic, -6c,9c-undecadienoic, -10c,13c-pentadecadienoic acid. They have been introduced into the 2-position of 1-stearoyl- and 1-linoleoyl-3-sn-glycerophosphocholine and cholesterol. Mass spectroscopy, 1H-NMR, IR and fluorescence spectroscopy and different chromatographic procedures have been applied to confirm and characterize their structures. The properties of the different fluorescent-labelled phosphatidylcholines in monomolecular films have been determined by the Langmuir technique.     

Alkaloids of some Mexican Zanthoxylum species

Two new 4-quinazolone alkaloids have been isolated from seed husks of Zanthoxylum arborescens. Based on their spectroscopic properties they have been assigned structures, 1-methyl-3-(2′-phenylethyl)-1H,3H-quinazoline-2,4-dione and 1-methyl-3-[2′-(4″-methoxyphenyl)ethyl]-1H,3H-quinazoline-2,4-dione. These structural assignments have been confirmed by synthesis. Skimmianine has been obtained from leaf extracts of Z. dimoncillo and Z. caribaeum while skimmianine and scopeletin have been isolated from leaf extracts of Z. fagara.     

Intracellular functions of galectins

Many galectin family members are detected primarily intracellularly in most of the systems studied, although certain members can be found both inside and outside of cells. Specific functions that are consistent with their intracellular localization have now been documented for some of the galectins. Galectin-1 and -3 have been identified as redundant pre-mRNA splicing factors. Galectin-3, -7, and -12 have been shown to regulate cell growth and apoptosis, being either anti-apoptotic or pro-apoptotic. Galectin-3 and -12 have been shown to regulate the cell cycle. In some cases, the mechanisms by which galectins exert their functions have been partially delineated in relation to known intracellular pathways associated with these processes. In addition, a number of intracellular proteins involved in these processes have been identified as the interacting ligands of certain galectins. This review summarizes the intracellular activities displayed by several galectins and discusses the possible underlying mechanisms.     

A reassessment of the binding of napthaleneacetic acid by membrane preparations from maize

Naphthalene-1-acetic acid (NAA) binding by membrane fractions derived from maize has been re-evaluated. Using a computer curve-fitting procedure only one major type of NAA binding, in terms of binding affinity, could be identified. Auxins, antiauxins and structurally related compounds have been tested for their competitive effect on NAA binding and the inhibitor constants for a number of these have been determined. Extracts from various plant species have been examined for their NAA binding ability, but all showed much less binding than maize leaf or coleoptile preparations. The possibility of the NAA binding by maize extracts being due to a true hormone receptor is discussed.Abbreviations BA benzoic acid - CPIB p-chlorophenoxyisobutyric acid - 2,4-D 2,4-dichlorophenoxyacetic acid - DCB 2,4-dichlorobenzoic acid - IAA indolyl-3-acetic acid - NAA napthalene-1-acetic acid - 2-NAA napthalene-2-acetic acid - NAOA napthalene-2-oxyacetic acid - PA phenylacetic acid - PU phenylurea - 2,4,5-T 2,4,5-trichlorophenoxyacetic acid - TIBA 2,3,5-triiodobenzoic acid     

Microcirculatory bed of the bulbar conjunctiva in 3- to 9-month-old fetuses

In 32 corpses of 3-9-month-old fetuses the diameter, length amount of the microcirculatory bed vessels and their wall thickness have been studied in different areas of the eye bulb conjunctiva by means of impregnation after Kuprianov. General morphofunctional vascular peculiarities have been revealed. They are connected with age and structure of the developing tissues in the eye bulb conjunctiva. Two stages of development have been defined: 3-6 and 7-9 months.     

Total asymmetric synthesis of (-)-conduramine B-1 and of its enantiomer. N-Benzyl derivatives of conduramine B-1 are beta-glucosidase inhibitors

The 'naked sugars' (+)- and (-)-7-oxabicyclo[2.2.1]hept-5-en-2-one have been converted into (-)-conduramine B-1 ((-)-3) and its enantiomer (+)-3, respectively. They have been condensed with a variety of aldehydes in the presence of NaBH(OAc)(3). The N-substituted derivatives 4 and ent-4 so-obtained have been tested against two alpha-glucosidases, two amyloglucosidases, two beta-glucosidases and one beta-xylosidase for their inhibitory activities. Although (-)-3 and (+)-3 do not inhibit any of these enzymes at 1mM concentration, N-benzylated derivatives of (-)-conduramine B-1 are selective and competitive inhibitors of beta-glucosidases with K(i) in low micromolecular range.     

Deciphering the role of 14-3-3 proteins

14-3-3 Proteins are found to bind to a growing number of eukaryotic proteins and evidence is accumulating that 14-3-3 proteins serve as modulators of enzyme activity. Several 14-3-3 protein recognition motifs have been identified and an increasing number of target proteins have been found to contain more than one binding site for a 14-3-3 protein. It is thus possible that 14-3-3 dimers function as clamps that simultaneously bind to two motifs within a single binding partner. Phosphorylation of a number of binding motifs has been shown to increase the affinity for 14-3-3 proteins but other mechanisms also regulate the association. It has recently been demonstrated that fusicoccin induces a tight association between 14-3-3 proteins and the plant plasma membrane H⁺-ATPase. Phorbol esters and other hydrophobic molecules may have a similar effect on the association between 14-3-3 proteins and specific binding partners.     

Catecholamines in plants

Catecholamines (CAs) are neurotransmitters in mammals. They have been found in 44 plant families, but no essential metabolic function has been established for them. They are precursors of benzo[c]phenanthridine alkaloids, which are the active principal ingredients of many medicinal plant extracts. CAs have been implicated to have a possible protective role against insect predators, injuries, and nitrogen detoxification. They have been shown to promote plant tissue growth, somatic embryogenesis from in vitro cultures, and flowering. CAs inhibit indole-3-acetic acid oxidation and enhance ethylene biosynthesis. They have also been shown to enhance synergistically various effects of gibberellins.Abbreviations CA(s) catecholamine(s) - FW fresh weight - dopa 3,4-dihydroxyphenylalanine - DW dry weight - TCL thin cell layer - dicamba 3,6-dichloro-2-methoxybenzoic acid - GA gibberellic acid - IAA indoleacetic acid - cAMP adenosine, 3,5-cyclic monophosphate - ACC 1-aminocyclopropane-l-carboxylic acid.     

Carotenoids in ripe green and in autumn senescing leaves of apple tree: I - Qualitative composition of free carotenoids,xanthophyll esters and fatty acids of esters

Abstract

By different chemical, spectral and chromatographic procedures seven carotenoids, two carotenes (α- and β-carotene) and five free xanthophylls (violaxanthin, lutein, antheraxanthin, zeaxanthin and neoxanthin) have been isolated and identified in green apple leaves. In autumn senescing leaves, besides the above seven carotenoids, the occurrence of at least seven xanthophyll esters has also been proved. Four esters, violaxanthin mono- and diester and lutein mono- and diester, (≥90% of total esters) and a minor component, neoxanthin triester, have been identified. Another minor component is most probably a monoester of antheraxanthin; the seventh, present in traces, has not been identified.

The fatty acids combined with the above xanthophyll esters have been analysed by gas-chromatography. The unusual presence of low molecular weight fatty acids, C7-C11, has been registered (1,5-8% of the total); caprilic and capric acids have been identified. Lauric acid with three minor homologous (2-7% and myristic acid (9-15%) are also present. The major component, palmitic acid, with palmitoleic and two other minor components, reaches 36-44%. In addition a remarkable presence of oleic acid (12-26%) has been observed together with stearic (8-10%), linolenic (5-6%), arachidic (0,7-2,5%) and linolenic-gadoleic acids (2,5-9,3%).     

1H and 15N resonance assignments of oxidized flavodoxin from Anacystis nidulans with 3D NMR

Proton and nitrogen-15 sequence-specific nuclear magnetic resonance assignments have been determined for recombinant oxidized flavodoxin from Anacystis nidulans (169 residues, Mr 19,048). Assignments were obtained by using 15N-1H heteronuclear three-dimensional (3D) NMR spectroscopy on a uniformly nitrogen-15 enriched sample of the protein, pH 6.6, at 30 degrees C. For 165 residues, the backbone and a large fraction of the side-chain proton resonances have been assigned. Medium- and long-range NOE's have been used to characterize the secondary structure. In solution, flavodoxin consists of a five-stranded parallel beta sheet involving residues 3-9, 31-37, 49-56, 81-89, 114-117, and 141-144. Medium-range NOE's indicate the presence of several helices. Several 15N and 1H resonances of the flavin mononucleotide (FMN) prosthetic group have been assigned. The FMN-binding site has been investigated by using polypeptide-FMN NOE's.     

Synthesis and chemiluminescent characteristics of two new acridinium esters

Two new acridinium esters with a 2-(succinimidyloxycarbonyl)ethyl side arm, namely, 9-(2,6-dibromophenoxycarbonyl)-10-methyl-2-(2-(succinimidyloxycarbonyl)ethyl)acridinium trifluoromethanesulfonate and 9-(4-(2-(succinimidyloxycarbonyl)ethyl)phenoxycarbonyl)-2,7-dimethoxy-10-methylacridinium triflate, have been produced and characterized. The chemiluminescent properties and hydrolytic stabilities of the new acridinium esters have been investigated.     

Potent inhibition of retinoic acid metabolism enzyme(s) by novel azolyl retinoids

Novel (+/-)-4-azolyl retinoic acid analogues 4, 5, 7 and 8 have been designed and synthesized and have been shown to be powerful inhibitors of hamster microsomal all-trans-retinoic acid 4-hydroxylase enzyme(s). (+/-)-4-(1H-Imidazol-1-yl)retinoic acid (4) is the most potent inhibitor of this enzyme reported to date.     

Flavonoids from the seeds of Lonchocarpus costaricensis

Seven flavonoids have been isolated from the seeds of Lonchocarpus costaricensis of which four appear to be novel. The new compounds have been identified as the β-hydroxychalcone demethylpraecansone-B and the flavanones 7-(3,3-dimethylallyloxy)-8-(3-hydroxy-3-methyl-trans-but-1-enyl)flavanone, 7-(3,3-dimethylallyloxy)-8-(3,3-dimethylallyl)-5-methoxyflavanone and 8-(3,3-dimethylallyl)-5,7-dimethoxyflavanone.     

Results of cytogenetic examinations in 255 married couples with a history of infertility]

The results of cytogenetic examination carried out in 255 couples with a history of infertility have been analysed. Chromosomal aberrations have been detected in 15 examinations (6.7%) with predominance of translocations (mutual - 3.6%; Robertson' - 1.3%). Identified aberrations have been noted in 9 women and 6 men. The obtained results have been analysed in relation to the number of abortions, dead and live newborn babies with inherited abnormalities. It was found that the incidence of chromosomal aberrations increases with the number of the spontaneous abortions in anamnesis. Such aberrations have also been more frequent in the families in which spontaneous abortions have been accompanied by other fertility disorders.     

Conformation of the third domain of turkey ovomucoid in solution. Structural analysis by two-dimensional Overhauser nuclear effect spectroscopy]

The conformations of a polypeptide chain of turkey ovomucoid third domain and its modified form with split reactive site peptide bond Leu-18--Glu-19 have been determined by the literary two-dimensional nuclear Overhauser effect spectroscopy data using an earlier suggested method. It has been found that the polypeptide domain backbone contains an alpha-helical fragment (residues 32-47), five segments having extended conformation (1-5, 11-17, 19-25, 29-31, 48-50) and beta-turn type 1 (26-29). Segments 23-26, 28-31 and 50-51 form an antiparallel beta-structure. Conformational states of the residues entering irregular domain segments have been analysed. Splitting of the reactive site peptide bond Leu-18--Glu-19 is shown to cause insignificant changes in the conformations of a number of amino acid residues except for Val-6 and Asp-7 ones which undergo essential conformational alterations. The conformations of domain in solution and of japanese quail ovomucoid third domain in crystal have been compared. The root-mean-square deviations for phi and psi angles indicate their high similarity. The conformations of turkey ovomucoid third domain and proteinase inhibitor BUSI IIA in solution have been analysed. In spite of moderate (50%) homology of primary structures, some 75% of amino acid residues are shown to have close conformational phi and psi parameters.     

Insect trypanosomatids: the need to know more

Of ten recognized trypanosomatid genera, only two - pathogenic Trypanosoma and Leishmania - have been actively investigated for any length of time while the plant flagellates - Phytomonas - have recently begun to attract attention due to their role as agricultural parasites. The remaining genera that comprise parasites associated with insects have been largely neglected except for two or three containing popular isolates. This publication reviews current knowledge of trypanosomatids from insects.     

(R)-3-(N-methylpyrrolidin-2-ylmethyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole derivatives as high affinity h5-HT1B/1D ligands

A series of (R)-3-(N-methylpyrrolidin-2-ylmethyl)-5-(1,2,3,6-tetrahydropyridin-4-yl)-1H-indole derivatives (2) have been prepared using parallel synthesis, and their structure-activity relationship studied. High affinity human 5-HT(1B/1D) (h5-HT(1B/1D)) ligands have been identified.     

Isolation and identification of two isomeric glutamylselenocystathionines from the seeds of Astragalus pectinatus

Two glutamylselenocystathionines have been isolated from the seeds of Astragalus pectinatus. These have been identified as 2-γ-glutamylamino-4-(2-amino-2-carboxyethylselenyl) butyric acid and 2-amino-4-(2-γ-glutamylamino-2-carboxyethylselenyl) butyric acid. The evidence for the natural occurrence of the corresponding glutamylcystathionines is also presented.     

Synthesis, structure and reactivity of the homoleptic iron(II) complex of the novel 4′-(4?-pyridyl-N-oxide)-2,2′:6′,2″-terpyridine ligand

The new ligand 4′-(4?-pyridyl-N-oxide)-2,2′:6′,2″-terpyridine (pyNoxterpy) and its homoleptic iron(II) complex have been synthesised, and structural and spectroscopic studies have been carried out. The obtained results have been compared with the reported data for the parent ligand 4′-(4?-pyridyl)-2,2′:6′,2″-terpyridine (pyterpy) and its homoleptic iron(II) complex. Significant differences between the spectral and electrochemical properties of the metal complexes have been found, derived from the changes in the electronic properties of the coordinated ligands.     

Homoleptic ruthenium (II) complexes containing asymmetric tridentate 2-(benzimidazole-2-yl)-1,10-phenanthroline likes ligands: syntheses, characterization and DNA binding

Two novel homoleptic ruthenium (II) complexes containing asymmetric tridentate ligands, 2-(benzimidazole-2-yl)-1,10-phenanthroline (PHBI) and 2-(naphtho[2,3-d]imidazole-2-yl)-1,10-phenanthroline (PHNI) have been synthesized and characterized by elemental analysis, mass spectra, (1)H NMR, and electronic spectroscopy. The DNA-binding properties of the complexes have been investigated by spectroscopic methods and viscosity measurements. The results indicate that the two complexes interact with DNA via electrostatic interaction, and the mechanisms of DNA binding with the complexes have also been discussed.