Flavans from Zephyranthes flava

A new optically active flavan aglucone, 7-hydroxy-3′,4′-methylenedioxyflavan, and its 7-glucoside have been isolated from the bulbs of Zephyranthes flava, collected at flowering. Additionally, two known flavans, 7,4′-dihydroxy-3′-methoxyflavan and 7-methoxy-2′-hydroxy-4′,5′-methylenedioxyflavan, have been isolated for the first time from this species. The structures of these flavans have been established by comprehensive analyses (UV, IR, ¹H NMR, ¹³C NMR, mass spectrometry, [α]_D) of the compounds and their acetates, and also by chemical correlation.     

Physicochemical and Light Scattering Studies on Ribosome Particles

The light scattering technique has been used to measure the molecular weight of Escherichia coli ribosomes. The 30S, 50S, and 70S components have been isolated and purified. The refractive index increment dn/dc was found to have the same value, (0.20 ±0.01) cm³/g, for the three species. The molecular weights are (1.0 ±0.1)·10⁶, (1.7 ±0.1)·10⁶, and (2.9 ±0.3)·10⁶ daltons respectively. Some information about the dimensions in solution (radius of gyration) and the interaction constant (second virial coefficient) have been obtained, and their significance is discussed.     

pMG7-mediated restriction of Pseudomonas aeruginosa phage DNAs is determined by a class II restriction endonuclease.

A class II restriction endonuclease, PaeR7, has been isolated from a Pseudomonas aeruginosa strain containing the resistance plasmid pMG7. The activity cannot be isolated from an isogenic strain which does not contain this resistance plasmid. EndoR· PaeR7 requires Mg²⁺ for activity but does not require ATP or S-adenosyl-l-methionine. Specific digestion patterns are produced upon agarose gel electrophoresis of substrate DNAs which have been digested with the enzyme. The enzyme is the biochemical basis for the pMG7-mediated phage interference reported by Jacoby and Sutton (1977). DNAs isolated from restricted phages act as substrates for the enzyme while DNAs isolated from unrestricted phages and phages which have been modified by growth on strains containing pMG7 do not act as substrates for the enzyme.     

Allele-specific differences in ryanodine receptor 1 mRNA expression levels may contribute to phenotypic variability in malignant hyperthermia

Background

In the recessive aminoaciduria Lysinuric Protein Intolerance (LPI), mutations of SLC7A7/y+LAT1 impair system y⁺L transport activity for cationic amino acids. A severe complication of LPI is a form of Pulmonary Alveolar Proteinosis (PAP), in which alveolar spaces are filled with lipoproteinaceous material because of the impaired surfactant clearance by resident macrophages. The pathogenesis of LPI-associated PAP remains still obscure. The present study investigates for the first time the expression and function of y+LAT1 in monocytes and macrophages isolated from a patient affected by LPI-associated PAP. A comparison with mesenchymal cells from the same subject has been also performed.

Methods

Monocytes from peripheral blood were isolated from a 21-year-old patient with LPI. Alveolar macrophages and fibroblastic-like mesenchymal cells were obtained from a whole lung lavage (WLL) performed on the same patient. System y⁺L activity was determined measuring the 1-min uptake of [³H]-arginine under discriminating conditions. Gene expression was evaluated through qRT-PCR.

Results

We have found that: 1) system y⁺L activity is markedly lowered in monocytes and alveolar macrophages from the LPI patient, because of the prevailing expression of SLC7A7/y+LAT1 in these cells; 2) on the contrary, fibroblasts isolated from the same patient do not display the transport defect due to compensation by the SLC7A6/y+LAT2 isoform; 3) in both normal and LPI monocytes, GM-CSF induces the expression of SLC7A7, suggesting that the gene is a target of the cytokine; 4) GM-CSF-induced differentiation of LPI monocytes is comparable to that of normal cells, demonstrating that GM-CSF signalling is unaltered; 5) general and respiratory conditions of the patient, along with PAP-associated parameters, markedly improved after GM-CSF therapy through aerosolization.

Conclusions

Monocytes and macrophages, but not fibroblasts, derived from a LPI patient clearly display the defect in system y⁺L-mediated arginine transport. The different transport phenotypes are referable to the relative levels of expression of SLC7A7 and SLC7A6. Moreover, the expression of SLC7A7 is regulated by GM-CSF in monocytes, pointing to a role of y+LAT1 in the pathogenesis of LPI associated PAP.     

Diterpenoids from sideritis pusilla subsp. flavovirens

Several new 14-hydroxybeyerene acetates have been isolated from the aerial parts of Sideritis pusilla subsp. flavovirens. In addition, an ent-kaur-15-ene (siderol) and a new ent-7α, 18-dihydroxybeyer-15-ene (flavovirol) have been obtained from the same source. The structures of these new acetates have been established by chemical and spectroscopic means and the structure of flavovirol has been confirmed by ¹³C NMR.     

Cinnamic acid amides from Chenopodium album: effects on seeds germination and plant growth

Seven cinnamic acid amides have been isolated from Chenopodium album. The structures have been attributed by means of their spectral data. One of them, N-trans-4-O-methylferuloyl 4′-O-methyldopamine, is described for the first time. Their effects on germination and growth of dicotyledons Lactuca sativa L. (lettuce) and Lycopersicon esculentum L. (tomato) and of monocotyledon Allium cepa L. (onion) as standard target species have been studied in the range concentration 10⁻⁴-10⁻⁷ M.     

Determination of nucleotide sequences from double-stranded regions of HeLa cell nuclear RNA

Double-stranded regions which comprise about 4% of isolated HeLa cell heterogeneous nuclear RNA have been characterized by RNA fingerprinting and sequencing analysis. The simplicity of the pattern in two-dimensional RNA fingerprints suggests a sequence complexity of about 1000 nucleotides. The nucleotide sequences of six prominent RNase T₁-resistant oligonucleotides (ranging in size from 7 to 9 bases) have been determined using isolated double-stranded nuclear RNA labeled in vivo with ³²P-labeled inorganic phosphate. We conclude that (here exists a substantial subpopulation of simple, potentially complementary sequences common to much of the heterogeneous nuclear RNA population and interspersed with other kinds of sequences.     

Isolation and characterization of a tomato Acid phosphatase complementary DNA associated with nematode resistance

The tomato (Lycopersicon esculentum) acid phosphatase-1 (Apase-1¹, EC 3.1.3.2) isozyme variant, genetically linked to the root-knot nematode resistance locus (Mi) on chromosome 6, has been purified by a rapid procedure from tomato cell suspension cultures. Peptide fragments of the purified enzyme were generated from trypsin and Lys-C endoprotease digests and separated by reverse-phase high-performance liquid chromatography. Amino acid sequences derived from the purified peptide fragments represented >50% of the total amino acid content of the protein and enabled the construction of degenerate oligonucleotide probes that were used to screen a tomato cell culture complementary DNA library. Clones corresponding to full-length coding sequences for Apase-1 have been isolated and sequenced. Southern blot analysis of DNA isolated from a number of tomato cultivars shows that the Apase-1¹ gene (aps1) is present at one copy per genome and that genotypes containing the aps1¹ allele have restriction fragment length polymorphisms that distinguish them from cultivars having the aps1⁺ allele. Segregation analysis demonstrates that the restriction fragment length polymorphisms are associated with the aps1 locus. Tomato Apase-1¹ is also found to have significant homology at the amino acid sequence level to a class of vegetative storage proteins characterized in soybean.     

24α-Methyl-5α-cholest-7-en-3β-ol from seed oil of Helianthus annuus

24-Methyl-5α-cholest-7-en-3β-ol (24-methyllathosterol) isolated from the seed oil of Helianthus annuus was shown to have 24α-configuration by ¹H NMR spectroscopy. The stereochemistry at C-24 of some other 24-alkylsterols isolated from this plant material also was determined.     

Multiple forms of Vicia faba α-galactosidases and their relationships

Three highly purified α-galactosidases, I, II¹ and II² have been isolated from resting Vicia faba seeds. Form I (MW 160 000) is a tetrame     

The major flavonoids of the seed of Tephrosia apollinea

A total of six complex 7-oxygenated-8-prenylflavones have been isolated from the seeds of Tephrosia apollinea and identified as the diastereoisomers (?)-semiglabrin and (?)-pseudosemiglabrin, (+)-glabratephrin, (+)-glabratephrinol, appollinine (7-methoxy-8-[3″-(2″,5″-dihydro-5″,5″-dimethyl-2″-oxofuryl)]-flavone and lanceolatin-A. The use of ¹³C NMR in the structure elucidation of flavones of this type is discussed. The potential chemotaxonomic value of Tephrosia flavones of the type isolated from T. apollinea is explored.     

Identification and in vitro anti-esophageal cancer activity of a series of halogenated monoterpenes isolated from the South African seaweeds Plocamium suhrii and Plocamium cornutum

Five known (1, 2, 4, 6 and 7) halogenated monoterpenes together with 1Z,3R^∗,4S^∗,5E,7Z)-1-bromo-3,4,8-trichloro-7-(dichloromethyl)-3-methylocta-1,5,7-triene (3) and (3R^∗,4S^∗)-3,4,6,7-tetrachloro-3,7-dimethyl-octen-1-ene (5) were isolated from the red macroalga Plocamium suhrii and their structures deduced from their spectroscopic data. The seven compounds from P. suhrii together with five related compounds from Plocamium cornutum have been evaluated for their cytotoxic effects on an esophageal cancer cell line (WHCO1). Compounds 1-6 showed greater cytotoxicity in this assay as compared to the known anticancer drug cisplatin.     

Dominant chromosomal mutation bypassing chromosomal genes needed for killer RNA plasmid replication in yeast

Yeast strains carrying a double-stranded RNA plasmid of 1.4–1.7 x 10⁶ daltons encapsulated in virus-like particles secrete a toxin that kills strains lacking this plasmid. The plasmid requires at least 24 chromosomal genes (pets, and mak1 through mak23) for its replication or maintenance. We have detected dominant Mendelian mutations (called KRB1 for killer replication bypass) that bypass two chromosomal genes, mak7 and pets, normally needed for plasmid replication. Strains mutant in mak7 and carrying the bypass mutation (mak7–1 KRB1) are isolated as frequent K⁺R⁺ sectors of predominantly K^-R ^- segregants from crosses of mak7–1 with a wild-type killer. All KRB1 mutations isolated in this way are inherited as single dominant centromere-linked chromosomal changes. They define a new centromere. KRB1 is not a translational suppressor. KRB1 strains contain a genetically normal killer plasmid and ds RNA species approximately the same in size and amount as do wild-type killers. Bypass of both mak7 and pets by one mutation suggests that these two genes are functionally related.

Two properties of the inheritance of KRB1 indicate an unusually high reversion frequency: (1) Heat or cycloheximide (treatments known to cure strains of the wild-type killer plasmid) readily induce conversion of mak7–1 KRB1 strains from killers to nonkillers with concomitant disappearance of KRB1 as judged by further crosses, and (2) mating two strains of the type mak7–1 KRB1 with each other yields mostly 2 K⁺R⁺: 2 K^-R^- segregation, although the same KRB1 mutation and the same killer plasmid are present in both parents.

     

Halogenated anthraquinones from the rare southern Illinois lichen Lasallia papulosa

Abstract:Four anthraquinones were isolated from the foliose lichen, Lasallia papulosa (Ach.) Llano. Two of the anthraquinones are known compounds, previously isolated from Lasallia papulosa, while the other two were reported previously as secondary metabolites from laboratory-cultured Nephroma laevigatum, and are isolated here for the first time from lichens in their natural habitat. All compounds were characterized by UV spectrophotometry, mass spectrometry, ¹H NMR and ¹³C NMR. The products were identified as 7-chloroemodin, valsarin (7-chloro-5-hydroxyemodin), 5-chloro-1- O -methylemodin and 5-chloro-1- O -methyl-ω-hydroxyemodin.     

Blockade by Polyphloretin Phosphate of the Prostaglandin F<Subscript>2α</Subscript>, Action on Isolated Human Bronchi

POLYPHLORETIN phosphate (PPP), a polymer with an inhibitory effect on some enzyme systems, such as alkaline phosphatase and hyaluronidase, has been synthesized by Diczfalusy et al.¹ by phosphorylating phloretin with phosphorus oxychloride. PPP has a molecular weight of about 15,000 and is readily soluble in water at pH 7. It has been tried in the treatment of oedema^2,3 and in vitro it inhibits the aggregation of red blood corpuscles⁴ and selectively antagonizes the effect of prostaglandin E₂ (PGE₂) on the intraocular pressure of the rabbit eye⁵. In the light of this finding we have examined whether PPP (supplied by Dr B. Högberg) could also modify the action of prostaglandins, when tested on some other preparation— in this case isolated human bronchi. During this study an investigation of the inhibition by PPP of the PGE₂ and PGF_2α action on isolated bird colon, rabbit jejunum and uterus has been reported⁶. It has been shown that PGE₁ and usually also PGE₂ have a bronchodilating effect in guinea-pig^7,8 and man⁹, while PGF_2α constricts bronchial smooth muscle in vivo and invitro^8,10,11. PGF_2α and PGE₂ have been isolated from human lungs^12,13 and both seem to be released in the anaphylactic reaction of isolated guinea-pig lung.     

Three flavonoid glycosides containing acetylated allose from stachys recta

By means of ¹³C and ¹H NMR spectroscopy three flavone glycosides, obtained from Stachys recta, were identified as 7-O-(2″-O-6″′-O-acetyl-β-D-allopyranosyl-β-D-glucopyranosides) of 4′-O-methylisoscutellarein, isoscutellarein and 3′-hydroxy-4′-O-methylisoscutellarein. The latter two compounds are isolated for the first time. Only mannose and glucose have been reported previously as sugar components of flavonoids of the genus Stachys.     

Novel Alleles of gon-2, a C. elegans Ortholog of Mammalian TRPM6 and TRPM7, Obtained by Genetic Reversion Screens

TRP (Transient Receptor Potential) cation channels of the TRPM subfamily have been found to be critically important for the regulation of Mg²⁺ homeostasis in both protostomes (e.g., the nematode, C. elegans, and the insect, D. melanogaster) and deuterostomes (e.g., humans). Although significant progress has been made toward understanding how the activities of these channels are regulated, there are still major gaps in our understanding of the potential regulatory roles of extensive, evolutionarily conserved, regions of these proteins. The C. elegans genes, gon-2, gtl-1 and gtl-2, encode paralogous TRP cation channel proteins that are similar in sequence and function to human TRPM6 and TRPM7. We isolated fourteen revertants of the missense mutant, gon-2(q338), and these mutations affect nine different residues within GON-2. Since eight of the nine affected residues are situated within regions that have high similarity to human TRPM1,3,6 and 7, these mutations identify sections of these channels that are potentially critical for channel regulation. We also isolated a single mutant allele of gon-2 during a screen for revertants of the Mg²⁺-hypersensitive phenotype of gtl-2(-) mutants. This allele of gon-2 converts a serine to phenylalanine within the highly conserved TRP domain, and is antimorphic against both gon-2(+) and gtl-1(+). Interestingly, others have reported that mutation of the corresponding residue in TRPM7 to glutamate results in deregulated channel activity.     

Bacterial Hemoglobins and Flavohemoglobins for Alleviation of Nitrosative Stress in Escherichia coli

Escherichia coli MG1655 cells expressing novel bacterial hemoglobin and flavohemoglobin genes from a medium-copy-number plasmid were grown in shake flask cultures under nitrosative and oxidative stress. E. coli cells expressing these proteins display enhanced resistance against the NO^· releaser sodium nitroprusside (SNP) relative to that of the control strain bearing the parental plasmid. Expression of bacterial hemoglobins originating from Campylobacter jejuni (CHb) and Vitreoscilla sp. (VHb) conferred resistance on SNP-challenged cells. In addition, it has been shown that NO^· detoxification is also a common feature of flavohemoglobins originating from different taxonomic groups and can be transferred to a heterologous host. These observations have been confirmed in a specific in vitro NO^· consumption assay. Protein extracts isolated from E. coli strains overexpressing flavohemoglobins consumed authentic NO^· more readily than protein extracts from the wild-type strain. Oxidative challenge to the cells evoked nonuniform responses from the various cell cultures. Improved oxidative-stress-sustaining properties had also been observed when the flavohemoglobins from E. coli, Klebsiella pneumoniae, Deinococcus radiodurans, and Pseudomonas aeruginosa were expressed in E. coli.     

Stigmasta-7,E-24(28)-dien-3β-ol from Bryonia dioica roots

Stigmasta-7,E-24(28)-dien 3β-ol was isolated from the roots of Bryonia dioica; it has been previously synthesised, but never found in the plant kingdom. The stereochemistry of the 24(28) double bond was unambiguously proved by high resolution (250 MHz) ¹H NMR.