Mechanism of stigmasterol dealkylation in insect

Deuterated stigmasterols (10, 11 and 12) were chemically synthesized and fed to silk-worm larvae. GC-MS analysis of the metabolites, cholesterol (4) and desmosterol (6), indicates the migration of 25-hydrogen to C-24 position during stigmasterol dealkylation. 22,24(28)-Dienes(8a and 8b) were shown to be converted to 22,24-diene (5), desmosterol and cholesterol.     

Synthesis of Δ1[9]- and/or Δ8[9]-dehydroindolizidines and related compounds

A facile synthesis of Δ^1[9]- and/or Δ^8[9]-dehydroindolizidine and related compounds, consisting of dry distillation of γ-(N-2-piperidinonyl)butyric acid over soda-lime, is described. Reductions of these dehydroindolizidines and stereochemistry of 1-methylindolizidine are also described.     

Recent insights into iron homeostasis and their application in graminaceous crops

Higher plants utilize various mechanisms to maintain iron homeostasis. To acquire sparingly soluble iron from the rhizosphere, graminaceous plants synthesize natural iron (III) chelators known as mugineic acid family phytosiderophores (MAs). Recent research has uncovered various genes involved in iron uptake and translocation, as well as factors regulating the expression of these genes, especially in rice. Manipulation of these molecular components is used to produce transgenic crops with enhanced tolerance to iron deficiency, or with a high seed iron content. Since iron homeostasis is closely linked to that of other mineral elements, an understanding of this phenomenon will serve as the basis for the production of crops with low concentrations of toxic metals and transgenic plants for phytoremediation.     

Trivial source modules in blocks with cyclic defect groups

We shall present a method to get trivial source modules easily just by looking at values of ordinary characters at non-identity p-elements in finite groups instead of doing huge calculation. The method is only for a case where defect groups are cyclic. Nevertheless, it works well at least when we want to prove Broué’s abelian defect group conjecture for blocks which have elementary abelian defect groups of order p ².     

Luminescent Polymer Consisting of 9,12‐Linked o‐Carborane

The synthesis of novel luminescent polymer containing p‐phenylene‐ethynylene and 9,12‐linked o‐carborane units alternately in the main chain is reported. The obtained polymer exhibits intense blue photoluminescence, providing the first insights into the optical properties of a 9,12‐disubstituted o‐carborane dye.  π‐Conjugated substituent at 9 and/or 12‐positions in o‐carborane is electrically independent, and both the HOMO and the LUMO levels slightly increase, whereas LUMO of the π‐conjugated substituent at 1 and/or 2‐positions in o‐carborane decrease.  Thus, it is deduced that polymers consisting of the 9,12‐linked o‐carborane unit are able to be applied as light‐emitting materials.

     

Disulfide‐Unit Conjugation Enables Ultrafast Cytosolic Internalization of Antisense DNA and siRNA

Development of intracellular delivery methods for antisense DNA and siRNA is important. Previously reported methods using liposomes or receptor‐ligands take several hours or more to deliver oligonucleotides to the cytoplasm due to their retention in endosomes. Oligonucleotides modified with low molecular weight disulfide units at a terminus reach the cytoplasm 10 minutes after administration to cultured cells. This rapid cytoplasmic internalization of disulfide‐modified oligonucleotides suggests the existence of an uptake pathway other than endocytosis. Mechanistic analysis revealed that the modified oligonucleotides are efficiently internalized into the cytoplasm through disulfide exchange reactions with the thiol groups on the cellular surface. This approach solves several critical problems with the currently available methods for enhancing cellular uptake of oligonucleotides and may be an effective approach in the medicinal application of antisense DNA and siRNA.     

Evaluation of measurement uncertainty in the elemental analysis of sintered silicon carbide using laser ablation in liquid—inductively coupled plasma mass spectrometry with external calibration and isotope dilution

Accreditation and Quality Assurance - The goal of this study was to evaluate the uncertainty of elemental analytical methods that use laser ablation in liquid (LAL) as a pretreatment. After LAL...