We report a compact scanning transmission X-ray microscope newly designed and developed at the Photon Factory. The microscope has very compact size and is equipped with fully digitized control ...electronics to realize high stability, precise positioning and fast data acquisition. The hardware design of the microscope is described in detail. Results of measurement using test samples are also presented.
Summary
Background B‐cell‐activating factor belonging to the tumour necrosis factor family (BAFF) is known for its role in the survival and maturation of B cells. It has been recently suggested that ...BAFF also plays important roles in T‐cell activation in T‐cell mediated diseases such as psoriasis.
Objectives To investigate the role of BAFF in cutaneous T‐cell lymphoma (CTCL).
Methods BAFF messenger RNA (mRNA) expression in skin samples (24 CTCL cases and seven healthy controls) and in skin‐derived fibroblasts (five CTCL cases and five healthy controls) was examined by quantitative reverse transcription–polymerase chain reaction. We also performed immunohistochemical staining for BAFF and its receptors. Serum BAFF levels were measured in patients with CTCL (n = 46), atopic dermatitis (n = 36) or psoriasis (n = 27) and 27 healthy controls by enzyme‐linked immunosorbent assay.
Results Lesional skin of CTCL contained higher levels of BAFF mRNA than normal skin and the expression levels correlated with disease activity. BAFF mRNA expression levels were elevated in fibroblasts from CTCL skin. Tumour cells in the lesional skin of CTCL expressed BAFF and its receptors, while fibroblasts expressed only BAFF. Serum BAFF levels of CTCL patients were significantly higher than those of healthy controls and correlated with types of skin lesions and clinical stages. They also significantly correlated with serum soluble interleukin‐2 receptor and lactate dehydrogenase levels.
Conclusions BAFF expression in CTCL skin and serum BAFF levels are significantly increased and correlate with the severity of CTCL. These results suggest that BAFF may have important roles in the development of CTCL.
Background Patients with human immunodeficiency virus (HIV) infection exhibit various skin diseases. HIV‐associated eosinophilic folliculitis (EF) and pruritic papular eruption (PPE) are frequently ...seen.
Objective To understand the mechanisms underlying HIV‐associated EF and PPE.
Methods In order to know frequencies of EF and PPE among patients with HIV infection, we first collected HIV+ patients who visited dermatology clinic in National Center for Global Health and Medicine during February 2007. We next collected 25 serum samples from HIV+ patients with skin diseases from May 2008 to May 2010. Eight of 25 patients had EF (EF group), four had PPE (PPE group) and others had non‐itchy skin problems such as condyloma acuminatum (no itch group).
Results We first confirmed high frequencies of EF (10.7%) and PPE (5.3%) among 75 HIV+ patients who visited our clinic during one month. We then measured serum levels of CCL11, CCL17, CCL26 and CCL27. Serum CCL17 levels in EF were significantly higher than those of PPE and no itch group. Serum CCL26 and CCL27 levels in EF were higher than those of no itch group. The number of CD4+ cells in EF was significantly lower than that in no itch group.
Conclusion High serum levels of CCL17, CCL26 and CCL27, and low CD4+ cell counts may account for the development of HIV‐associated EF.
Background and purpose:
We investigated how McN‐A‐343 inhibited the alkylation of the M
1
muscarinic receptor by its nitrogen mustard derivative and that of ACh to identify whether it interacts ...allosterically or orthosterically.
Experimental approach:
We incubated the M
1
muscarinic receptor expressed in Chinese hamster ovary cells with ACh mustard for various periods of time in the presence of McN‐A‐343 or known allosteric and orthosteric ligands. After stopping the reaction and removing unreacted ligands, unalkylated receptors were measured using
3
HN‐methylscopolamine. Analogous experiments were done using a nitrogen mustard analog of McN‐A‐343. Affinity constants, cooperativity values for allosteric interactions and rate constants for receptor alkylation were estimated using a mathematical model.
Key results:
The kinetics of receptor alkylation by the nitrogen mustard derivatives of ACh and McN‐A‐343 were consistent with a two‐step model in which the aziridinium ion rapidly forms a reversible receptor complex, which converts to a covalent complex at a slower rate. The inhibition of receptor alkylation by acetycholine,
N
‐methylscopolamine and McN‐A‐343 was consistent with competitive inhibition, whereas that caused by gallamine was consistent with allosterism. Affinity constants estimated from alkylation kinetics agreed with those measured by displacement of
3
H
N
‐methylscopolamine binding.
Conclusions and implications:
Our results suggest that McN‐A‐343 and its nitrogen mustard derivative interact competitively with ACh and
N
‐methylscopolamine at the orthosteric site on the M
1
muscarinic receptor. Measuring how drugs modulate the kinetics of receptor alkylation by an irreversible ligand is a powerful approach for distinguishing between negative allosteric modulators and competitive inhibitors.
Low temperature heat capacity calorimetry has a long history in the field of chemical thermodynamics. Central research subjects were shifted according to the need and fashion of the times. By ...surveying the historical development, some suggestions to the new directions in the instrumentations and research subjects are given.
Background and purpose: We investigated how McN‐A‐343 inhibited the alkylation of the M1 muscarinic receptor by its nitrogen mustard derivative and that of ACh to identify whether it interacts ...allosterically or orthosterically.
Experimental approach: We incubated the M1 muscarinic receptor expressed in Chinese hamster ovary cells with ACh mustard for various periods of time in the presence of McN‐A‐343 or known allosteric and orthosteric ligands. After stopping the reaction and removing unreacted ligands, unalkylated receptors were measured using 3HN‐methylscopolamine. Analogous experiments were done using a nitrogen mustard analog of McN‐A‐343. Affinity constants, cooperativity values for allosteric interactions and rate constants for receptor alkylation were estimated using a mathematical model.
Key results: The kinetics of receptor alkylation by the nitrogen mustard derivatives of ACh and McN‐A‐343 were consistent with a two‐step model in which the aziridinium ion rapidly forms a reversible receptor complex, which converts to a covalent complex at a slower rate. The inhibition of receptor alkylation by acetycholine, N‐methylscopolamine and McN‐A‐343 was consistent with competitive inhibition, whereas that caused by gallamine was consistent with allosterism. Affinity constants estimated from alkylation kinetics agreed with those measured by displacement of 3HN‐methylscopolamine binding.
Conclusions and implications: Our results suggest that McN‐A‐343 and its nitrogen mustard derivative interact competitively with ACh and N‐methylscopolamine at the orthosteric site on the M1 muscarinic receptor. Measuring how drugs modulate the kinetics of receptor alkylation by an irreversible ligand is a powerful approach for distinguishing between negative allosteric modulators and competitive inhibitors.
We have recently reported an in vitro-evolved precursor tRNA
(pre-tRNA) that is able to catalyze aminoacylation on its own
3′-hydroxyl group. This catalytic pre-tRNA is susceptible
to RNase P RNA, ...generating the 5′-leader ribozyme and
mature tRNA. The 5′-leader ribozyme is also capable of
aminoacylating the tRNA in trans, thus acting as an
aminoacyl-tRNA synthetase-like ribozyme (ARS-like ribozyme).
Here we report its structural characterization that reveals
the essential catalytic core. The ribozyme consists of three
stem-loops connected by two junction regions. The chemical probing
analyses show that a U-rich region (U59–U62 in J2a/3 and
U67–U68 in L3) of the ribozyme is responsible for the
recognition of the phenylalanine substrate. Moreover, a GGU-motif
(G70–U72) of the ribozyme, adjacent to the U-rich region,
forms base pairs with the tRNA 3′ terminus. Our demonstration
shows that simple RNA motifs can recognize both the amino acid
and tRNA simultaneously, thus aminoacylating the 3′ terminus
of tRNA in trans.
We developed nine simple sequence repeat (SSR) markers useful for differentiating Japanese isolates of Magnaporthe grisea through a bioinformatic approach. Repeat sequences in the genome of M. grisea ...were identified by a Tandem Repeat Finding program. Length polymorphisms at 28 loci were examined, nine of which were selected on the basis of detected polymorphisms. These nine SSR markers showed a Nei's gene diversity ranging from 0.23 to 0.91 among 48 field isolates of two natural populations. These SSR markers are well suited for M. grisea epidemiology and population genetics.
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