13C CP/MAS NMR Spectral Analysis of 6-O-Tosyl, 6-Deoxy-6-iodo,and 6-Deoxy Derivatives of N-Acetylchitosan in a Solid State

6-O-Tosyl (1, d.s. 0.94, 80% yield), 6-deoxy-6-iodo (2, d.s. 0.49, 86% yield) and 6-deoxy (3, d.s. 0.49, 50% yield) derivatives of N-acetylchitosan were prepared, and a ¹³C CP/MAS NMR spectral analysis was performed because no suitable solvent for 3 was found. The ¹³C signal for CH₃ at C-6 in 3 was detected at 18.9 ppm, and that for C-4 in 1–3 appeared at 72.2–72.7 ppm, which is in a higher magnetic field than those (82.5–86.0 ppm) in N-acetylchitosan, 6-O- (ethylthio), 6-O-(benzylthio)- and 6-O-(methylthio)-thiocarbonyl derivatives, chitosan, and chitin. This strongly suggests a different molecular conformation for 1–3.     

A Ds-insertion mutant of OSH6 (Oryza sativa Homeobox 6) exhibits outgrowth of vestigial leaf-like structures, bracts, in rice

OSH6 (Oryza sativa Homeobox6) is an ortholog of lg3 (Liguleless3) in maize. We generated a novel allele, termed OSH6-Ds, by inserting a defective Ds element into the third exon of OSH6, which resulted in a truncated OSH6 mRNA. The truncated mRNA was expressed ectopically in leaf tissues and encoded the N-terminal region of OSH6, which includes the KNOX1 and partial KNOX2 subdomains. This recessive mutant showed outgrowth of bracts or produced leaves at the basal node of the panicle. These phenotypes distinguished it from the OSH6 transgene whose ectopic expression led to a “blade to sheath transformation” phenotype at the midrib region of leaves, similar to that seen in dominant Lg3 mutants. Expression of a similar truncated OSH6 cDNA from the 35S promoter (35S::ΔOSH6) confirmed that the ectopic expression of this product was responsible for the aberrant bract development. These data suggest that OSH6-Ds interferes with a developmental mechanism involved in bract differentiation, especially at the basal nodes of panicles. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The effect of astaxanthin and cadmium on rat erythrocyte G6PD, 6PGD,GR, and TrxR enzymes activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro

In this study, the effects of astaxanthin (AST) that belongs to carotenoid family and cadmium (Cd), which is an important heavy metal, on rat erythrocyte G6PD, 6PGD, GR, and TrxR enzyme activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro were studied. In in vitro studies, 6PGD enzyme was purified from rat erythrocytes with 2′,5′‐ADP Sepharose4B affinity chromatography. Results showed inhibition of enzyme by Cd at IC₅₀; 346.5 μM value and increase of 6PGD enzyme activity by AST. In vivo studies showed an increase in G6PD, 6PGD, and GR enzyme activities (P ? 0.05) and no chance in TrxR enzyme activity by AST. Cd ion inhibited G6PD, 6PGD, and GR enzyme activities (P ? 0.05) and also decreased TrxR enzyme activity (P ? 0.05). AST + Cd group G6PD enzyme activity was statistically low compared with control group (P ? 0.05). 6PGD and TrxR enzyme activities decreased without statistical significance (P ? 0.05); however, GR enzyme activity increased statistically significantly (P ? 0.05).     

Novel Potato Micro-Tuber-Inducing Compound, (3R,6S)-6-Hydroxylasiodiplodin,from a Strain of Lasiodiplodia theobromae

A novel potato micro-tuber-inducing compound was isolated from the culture broth of Lasiodiplodia theobromae Shimokita 2. The structure of the isolated compound was determined as (3R,6S)-6-hydroxylasiodiplodin by means of spectroscopic analyses, the modified Mosher method, and chemical conversion. The compound showed potato micro-tuber-inducing activity at a concentration of 10^?4 M, using the culture of single-node segments of potato stems in vitro.     

Synthesis of 3Z-Nonenal and 3Z,6Z-Nonadienal

3Z-Nonenal and 3Z, 6Z-nonadienal, potential biosynthetic precursors of 2E-nonenal and 2E, 6Z-nonadienal, were for the first time synthesized stereoseleclively.     

Mapping of the MouseLy-6, Xp-14, andGdc-1 loci to chromosome 15

TheLy-6 locus is now regarded as a gene complex consisting of at least five closely linked loci (Ly-6A-Ly-6E) whose polymorphic products are identified by monoclonal antibodies and distinguished by different tissue distributions.Ly-6 has been assigned by other investigators to chromosome (Chr) 9 (linked toThy-1 or to Chr 2. We report that theLy-6 gene complex, together with theXp-14 andGdc -1 loci, is situated on Chr 15 linked toGpt1. These new linkage data are derived from four sources: (1) three separate crosses that failed to demonstrate linkage ofLy-6 to eitherThy-4 on Chr 9 or to any of five genes present on Chr 2; (2) the NXSM recombinant inbred strains, which suggested the linkage ofLy-6 andXp-14 toGpt-1 on Chr 15; (3) severalGpt-1 andGdc-1 congenic strains that confirmed the assignment ofLy-6 andXp-14 to Chr 15; and (4) backcrosses that further confirmed the linkage ofLy-6, Gpt-1, Gdc-4, andXp-14, the probable gene order beingGpt-11/Ly-6 Xp-14-Gdc-1.     

Genetic characterisation of a further homoeoallelic series of grain esterase loci,Est-6, in wheat

Summary Isoelectric focussing in alkaline pH gels has permitted the identification of a new homoeoallelic series of genes,Est-6, encoding grain esterases in bread wheat,Triticum aestivum. Nullisomic analysis located these genes to the short arms of the homoeologous group 2 chromosomes. A search for polymorphism withinEst-6 revealed null alleles at each ofEst-A6,Est-B6 andEst-D6. A further homoeolocus,Est-M6, is present on chromosome arm2MS ofAegilops comosa.     

6-Deoxotyphasterol and 3-Dehydro-6-deoxoteasterone,Possible Precursors to Brassinosteroidsin the Pollen of Cupressus arizonica

Two new congeners (22R,23R,24S)-22,23-dihydroxy-24-methyl-5α-cholestan-3α-ol 2 and (22R,23R,24S)-22,23-dihydroxy-24-methyl-5α-cholestan-3-one 4 that are termed 6-deoxotyphasterol and 3-dehydro-6-eoxoteasterone, respectively, occur in relatively large amounts in the mature pollen of Cupressus arizonica. GC-MS, NMR spectroscopy, the reduction of 4 to 2, and the independent formation of 2 by the reduction of typhasterol were used to identify the new compounds. In the rice lamina bioassay, 2 showed weak activity. 6-Deoxocastasterone, castasterone, typha sterol, an epicastasterone-like compound, teasterone, 28-homocastasterone, 3-dehydroteasterone, brassinolide, and dolichosterone (or 24-epibrassinolide) were also present. These brassinosteroids were identified by co-chromatography with standards after being converted for an HPLC analysis of bioactive fractions. Six other peaks have not yet been assigned. 6-Deoxotyphasterol and 3-dehydro-6-deoxoteasterone should prove useful for exploring the early stages of the biosynthetic pathway(s) to brassinosteroids.     

Genetics,subcellular localization,and molecular characterization of 6-phosphogluconate dehydrogenase isozymes in tomato

Three independent genes are responsible for 6-phosphogluconate dehydrogenase (6PGDH) activity in tomato. 6Pgdh-2, located on chromosome 12, codes for subunits of an active dimer which is restricted to the plastids. 6Pgdh-1, chromosome 4, and 6Pgdh-3, chromosome 5, code for subunits which form three dimers—two homodimers and an intergenic heterodimer. The latter three isozymes are found in the cytosol. 6Pgdh-1, 6Pgdh-2, and 6Pgdh-3 code for subunits with estimated molecular weights of 49,500, 50,500, and 51,200, respectively. The intergenic heterodimer encoded by 6Pgdh-1 and 6Pgdh-3 is thus composed of subunits that differ in length by approximately 15 amino acid residues. Divergence in the length and primary subunit structure may account for the lower thermal stability of the intergenic heterodimer compared with the corresponding homodimers. A limited survey of other solanaceous plant species suggests that the duplication of cytosolic 6PGDH-coding genes found in tomato may be widespread in the family.This is journal article 1145, Agricultural Experiment Station, New Mexico State University. This research was supported by USDA Grant 82-CRCR-1-1014 to S. D. Tanksley. We acknowledge the technical support of Jaime Iglesias and Fernando Loiaza.     

Molecular cloning and characterization of NFBP6, a putative floral homeotic gene, from tobacco

 NFBP6 cloned from tobacco is most closely related to petunia FBP6, a putative C-function gene. Also, NFBP6 is expressed specifically in stamens and carpels. Thus, NFBP6 provides a useful tool for molecular characterization of flower development.     

The Synthesis of RNA Containing the Modified Nucleotides N 2-Methylguanosine and N 6, N 6-Dimethyladenosine

Abstract

The phosphoramidites of the naturally occurring modified nucleotides N ²-methylguanosine and N ⁶,N ⁶-dimethyladenosine were synthesized and incorporated into short oligoribonucleotides. Described are the syntheses of the phosphoramidites and the procedures used to deprotect oligoribonucleotides in which the O ⁶ of m²G is protected with a 2-(p-nitrophenyl)ethyl group.     

An endoplasmic reticulum stress regulator,Tmbim6, modulates secretory stage of mice molar

To understand the role of endoplasmic reticulum (ER)-stress in mice molar development, we studied Tmbim6 that antagonizes the unfolded protein response, using Tmbim6 knockout (KO) mice and in vitro organ cultivation with knocking down using small interfering RNA. During molar development, Tmbim6 is expressed in developing tooth at E14–E16, postnatal0 (PN0), and PN6. Mineral content in Tmbim6 KO enamel was reduced while dentin was slightly increased revealing ultrastructural changes in pattern formation of both enamel and dentin. Moreover, odontoblast differentiation was altered with increased Dspp expression at PN0 followed by altered AMELX localizations at PN5. These results were confirmed by in vitro organ cultivation and showed altered Bmp signaling, proliferation, and actin rearrangement in the presumptive ameloblast and odontoblasts that followed the altered expression of differentiation and ER stress-related signaling molecules at E16.5. Overall, ER stress modulated by Tmbim6 would play important roles in patterned dental hard tissue formation in mice molar within a limited period of development.     

A facile synthesis of (1S,5R,6S)-5-azido-6-benzyloxycyclohex-2-en-1-ol

A facile and short synthesis of (1S,5R,6S)-5-azido-6-benzyloxycyclohex-2-en-1-ol (1) has been achieved in high yield starting from 4,5-epoxycyclohex-1-ene by using a catalytic asymmetric allylic oxidation reaction.     

铜绿假单胞菌T6SS的组装、分泌、功能和调控

作为一种对抗真核细胞和原核细胞的强有力细菌武器,Ⅵ型分泌系统(type Ⅵ secretion system,T6SS)广泛存在于革兰氏阴性菌中。铜绿假单胞菌是一种对多种抗生素具有耐药性并能够在人体引发急性和慢性感染的条件致病菌,它编码3套独立的T6SS,分别为H1-、H2-和H3-T6SS。T6SS通过介导细菌间竞争、生物被膜的形成、金属离子的摄取以及与真核宿主细胞之间的相互作用,对铜绿假单胞菌在毒力和适应环境方面发挥重要作用。本文主要对铜绿假单胞菌T6SS的组装、效应蛋白的分泌、功能及调控机制展开综述,旨在为T6SS的研究提供一定的参考,并为铜绿假单胞菌感染的预防和治疗提供一定的指导。     

Nonlinkage between C6 and chromosome 6 markers

Summary C6 typing was performed in a family material by two different techniques: serum or plasma samples were subjected either to high-voltage agarose gel electrophoresis or to isoelectric focusing in polyacrylamide gel slabs. Proteins with C6 activity were then visualized by a specific, hemolytic assay.In 81 unrelated adults within the family material the following allele frequencies were found: C6 ^A:0.61 and C6 ^B:0.39.Linkage studies exclude linkage between C6 and HLA region marker loci, and also between C6 and another chromosome 6 marker locus PGM3.     

B-class MADS-box genes in trioecious papaya: two paleoAP3 paralogs, CpTM6-1 and CpTM6-2, and a PI ortholog CpPI

In the ABC model of flower development, B function organ-identity genes act in the second and third whorls of the flower to control petal and stamen identity. The trioecious papaya has male, female, and hermaphrodite flowers and is an ideal system for testing the B-class gene expression patterns in trioecious plants. We cloned papaya B-class genes, CpTM6-1, CpTM6-2, and CpPI, using MADS box gene specific degenerate primers followed by cDNA library screening and sequencing of positive clones. While phylogenetic analyses show that CpPI is the ortholog of the Arabidopsis gene PI, the CpTM6-1 and CpTM6-2 loci are representatives of the paralogous TM6 lineage that contain paleoAP3 motifs unlike the euAP3 gene observed in Arabidopsis. These two paralogs appeared to have originated from a tandem duplication occurred approximately 13.4 million year ago (mya) (bootstrap range 13.36 ± 2.42). In-situ hybridization and RT-PCR showed that the papaya B-class genes were highly expressed in young flowers across all floral organ primordia. As the flower organs developed, all three B-class genes were highly expressed in petals of all three-sex types and in stamens of hermaphrodite and male flowers. CpTM6-1 expressed at low levels in sepals and carpels, whereas CpTM6-2 expressed at a low level in sepals and at a high level in leaves. Our results showed that B-class gene homologs could function as predicted by the ABC model in trioecous flowers but differential expressions of CpTM6-1, and CpTM6-2, and CpPI suggested the diversification of their functions after the duplication events. Christine M. Ackerman, Qingyi Yu contributed equally to this work.     

Production of the taste/odor-causing compound,trans-2,cis-6-nonadienal,within the Synurophyceae

Although several species of the Synurophyceae have been associated with taste and odor problems in potable water supplies, electron microscopic-based field studies linked problematic blooms only toSynura petersenii Korshikov. Eventually, the organic compoundtrans-2,cis-6-nonadienal was implicated to cause the associated cucumberlike odors. The objective of this study was to survey unialgal cultures of various Synurophycean species for the occurrence oftrans-2,cis-6-nonadienal. The compound was detected throughout a 24-day growth assay with aS. petersenii isolate, but was not detected in an identical assay withSynura sphagnicola (Korshikov) Korshikov. In separate 24-day cultures,trans-2,cis-6-nonadienal was detected in two isolates from theS. petersenii species complex, but was not detected in isolates of twoMallomonas or fourSynura taxa not from theS. petersenii complex. These results support the hypothesis that production oftrans-2,cis-6-nonadienal is unique to taxa within theS. petersenii complex. When contrast-enhancing optics and specific specimen preparation techniques are employed, light microscopy can be used to distinguish taxa in theS. petersenii complex from all other Synurophycean taxa. These methods are suggested as an efficient way to monitortrans-2,cis-6-nonadienal-producing taxa in potable water supplies.Author for correspondence