Polymorphisms of E1 and GIGANTEA in wild populations of Lotus japonicus

In plants, timing of flowering is an essential factor that controls the survival rates of descendants. The circadian clock genes E1 and GIGANTEA (GI) play a central role in transmitting signals to FLOWERING LOCUS T (FT) in leguminous plants. Lotus japonicus is a wild Japanese species that ranges from northern Hokkaido to the southern Ryukyus and exhibits a wide range in terms of the time between seeding and first flowering. In this study, we first identified LjGI and analyzed polymorphisms of LjE1 and LjGI among wild populations covering the entire distribution range of this species in Japan. LjGI had a coding sequence (CDS) length of 3495 bp and included 14 exons. The homologies of DNA and amino acid sequences between LjGI and GmGI were 89 and 88 % (positive rate was 92 %), respectively. LjE1 harbored five nucleic acid changes in a 552 bp CDS, all of which were nonsynonymous; four of the changes were located in the core function area. LjE1 alleles exhibited partial north–south differentiation and non-neutrality. In contrast, the LjGI harbored one synonymous and one nonsynonymous change. Thus, our study suggests that LjE1 may be involved in the control of flowering times, whereas LjGI may be under strong purifying selection.     

Presence of an inactive protein immunologically analogous to cytochrome c oxidase in the inner membrane of sweet potato root mitochondria

A protein, which was immunoreactive to antibody against cytochrome c oxidase, was found in the mitochondrial membrane fraction of sweet potato root tissue. The protein was associated relatively weakly with the mitochondrial inner membrane as compared with cytochrome c oxidase. It exerted no cytochrome c oxidase activity and contained no heme a. The protein was purified by phenyl-Sepharose column chromatography and polyacrylamide gel electrophoresis. The molecular weight of its polypeptide chain was 57,000. In addition, the protein decreased during aging of tissue slices. It is therefore not improbable that the protein is a precursor of cytochrome c oxidase composed of only the subunits of cytoplasmic origin, since aging of tissue slices has been shown to result in an increase in the enzyme activity which is inhibited by chloramphenicol but not by cycloheximide.     

Detection of Human Cytomegalovirus DNA in Breast Milk by Means of Polymerase Chain Reaction

Three hundred and twenty-five breast milk samples were examined for the occurrence of human cytomegalovirus (HCMV) by cell culture method. Virus was isolated from the milk in 1 of 177 samples collected within 6 days after delivery, 2 of 115 samples collected during the period of 7 days to 1 month after delivery, 10 of 33 samples collected over 1 month after delivery. Next, we tried to amplify HCMV DNA from the breast milk samples from HCMV seropositive mothers and seronegative mothers at 1 month after delivery by polymerase chain reaction. HCMV DNA was detected in 12 of 13 samples from seropositive mothers and in none of 7 samples from seronegative mothers. It was thought that all women seropositive for HCMV principally shed the virus into their breast milk at 1 month after delivery.     

Absolute configuration and conformational analysis of C-glucoside of a resveratrol trimer: Structure of hopeaside E from Hopea utilis

In this study, we isolated a new glucoside of the resveratrol trimer (hopeaside E) from the stem wood of Hopea utilis. The glucoside structure is partially composed of balanocarpol (resveratrol dimer) after oxidative condensation of the (E)-resveratrol-10-C-β-glucopyranoside. The structure elucidation was achieved by spectroscopic analysis including NMR experiments, and the absolute configuration was determined on the basis of the comparative configurational analysis with the β-d-glucopyranosyl group. Conformational analysis was also performed by considering deshielding effects due to aromatic rings using computational methods of molecular modeling. The aglycone has six asymmetric carbons with two aliphatic hydroxyl groups attached to them that has not been reported in any other resveratrol derivative studies.     

Syntheses, properties, and structural characteristics of several new [tetrakis(1-pyrazolyl)borato]samarium(III) complexes: comparative study of the B(pyrazolyl)4 and BH(pyrazolyl)3 ligation

Although reactions of samarium(III) chloride, SmCl₃ · 6H₂O, with potassium hydrotris(1-pyrazolyl)borate K[BH(pz)₃] (pz = 1-pyrazolyl) in a molar ratio of (1/1) in THF afford [SmCl{BH(pz)₃}₂(Hpz)], similar reactions with K[B(pz)₄] gave rise to separation of anhydrous H[B(pz)₄]. The homoleptic eight-coordinate complex [Sm{B(pz)₄}₃] obtained from SmCl₃ · 6H₂O and threefold moles of K[B(pz)₄] was allowed to react with twofold moles of K[BH(pz)₃] to give a mixture of three major species [Sm{B(pz)₄}_n{BH(pz)₃}_(3 − n)] (n = 2, 1, 0), whereas similar reactions of [Sm{BH(pz)₃}₃] with K[B(pz)₄] did not proceed at all. The acetylacetonato (acac) complex [Sm{B(pz)₄}₂(acac)], derived from the triflate “Sm{B(pz)₄}₂(OTf)”, was treated with twofold moles of K[BH(pz)₃] and showed its quantitative conversion to [Sm{BH(pz)₃}₂(acac)]. However, analogous reaction of [Sm{BH(pz)₃}₂(acac)] with K[B(pz)₄] did not proceed. Accordingly, samarium(III) ion was determined to prefer coordination of BH(pz)₃ ligand to that of B(pz)₄, indicating less σ-donating electronic character of the latter. The complexes [Sm{B(pz)₄}₂(L-L)] (L-L = β-ketoenolato) in toluene-d₈ exhibited ¹H NMR spectroscopic equivalence of all four pyrazolyl groups at high temperatures, and are regarded as a new class of B(pz)₄ complexes, showing fast intramolecular exchange of their coordinated and uncoordinated pyrazolyl groups. Four compounds were crystallographically characterized.     

Commonly stabilized cytochromes c from deep-sea Shewanella and Pseudomonas

Two cytochromes c₅ (SBcytc and SVcytc) have been derived from Shewanella living in the deep-sea, which is a high pressure environment, so it could be that these proteins are more stable at high pressure than at atmospheric pressure, 0.1 MPa. This study, however, revealed that SBcytc and SVcytc were more stable at 0.1 MPa than at higher pressure. In addition, at 0.1–150 MPa, the stability of SBcytc and SVcytc was higher than that of homologues from atmospheric-pressure Shewanella, which was due to hydrogen bond formation with the heme in the former two proteins. This study further revealed that cytochrome c₅₅₁ (PMcytc) of deep-sea Pseudomonas was more stable than a homologue of atmospheric-pressure Pseudomonas aeruginosa, and that specific hydrogen bond formation with the heme also occurred in the former. Although SBcytc and SVcytc, and PMcytc are phylogenetically very distant, these deep-sea cytochromes c are commonly stabilized through hydrogen bond formation.     

Hepatic calcium-binding protein regucalcin concentration is decreased by streptozotocin-diabetic state and ethanol ingestion in rats

The alteration in calcium-binding protein regucalcin in the liver and serum of rats with streptozotocin (STZ)-diabetic state or ethanol ingestion was investigated. STZ (6.0 mg/100 g body weight) was subcutaneously administered in rats, and 1 or 3 weeks later they were sacrificed by bleeding. Liver regucalcin mRNA levels were not clearly altered by the diabetic state, as evidenced by Northern blotting using regucalcin cDNA (0.9 kb of open reading frame). Based on enzyme-linked immunoadsorbent assay (ELISA) with rabbit-anti-regucalcin IgG, hepatic regucalcin concentration was decreased about 50% of control levels by STZ treatment. However, serum regucalcin concentration was not significantly altered by STZ treatment. Meanwhile, when rats ingested ethanol (10 and 30%) in the drinking water for 2 weeks, liver regucalcin mRNA levels were clearly increased, although hepatic regucalcin concentration was significantly decreased. Serum regucalcin concentration was not appreciably altered. Serum transaminases (GOT and GPT) activities were significantly increased at 1 or 3 weeks after STZ administration in rats, while their activities were not altered by ethanol ingestion. The present study demonstrates that hepatic regucalcin concentration is decreased independent of mRNA expression in the STZ-diabetes and during ethanol ingestion in rats.     

Enhancement of plasma membrane (Ca2+-Mg2+)-ATPase activity in regenerating rat liver: Involvement of endogenous activating protein regucalcin

The alteration of (Ca²⁺-Mg²⁺)-ATPase activity in the plasma membranes of regenerating rat liver after a partial hepatectomy was investigated. Liver was surgically removed about two thirds of that of sham-operated rats. The reduced liver weight by partial hepatectomy was restored about 50% at 24 h after the surgery, and it was completely restored at 72 h. Regenerating liver significantly increased calcium content and plasma membrane (Ca²⁺-Mg²⁺)-ATPase activity between 12–48 h after hepatectomy. Those increases were maximum at 24 h after the surgery. The regenerating liver-induced increase in hepatic plasma membrane (Ca²⁺-Mg²⁺)-ATPase activity was completely abolished by the presence of anti-regucalcin IgG (1.0–4.0 g/ml). The regenerating liver-induced increase in hepatic plasma membrane (Ca²⁺-Mg²⁺)-ATPase activity was clearly inhibited by N-ethylmaleimide (2.5 and 5.0 mM) addition into the enzyme reaction mixture. This NEM effect was also seen for the activatory effect with regucalcin (0.25 M) addition on the enzyme activity in the plasma membranes from normal rat liver. The endogenous regucalcin may play a cell physiological role in the activation of the plasma membrane (Ca²⁺-Mg²⁺)-ATPase to maintain the intracellular calcium level in regenerating rat liver.     

Self-assembled pH-responsive hydrogels composed of the RATEA16 peptide

Peptide RATEA16 spontaneously self-assembled into higher-order nanofiber hydrogels with extremely high water content (>99.5% (wt/vol)) under physiological condition. The hydrogels could undergo pH-reversible transitions from viscous solution to elastic hydrogel and to precipitate. The supramolecular self-assembly and the three phase transitions are driven by hydrophobic interactions, intermolecular hydrogen bonds, and a combination of attractive or repulsive electrostatic interactions. These hydrogels are rich in beta-sheet nanofibers, as demonstrated by CD and FTIR data. Rheological measurements reveal that the viscoelasticity of the material can be tuned by environmental pH and peptide concentration. The storage modulus of the hydrogels increases with increasing peptide concentration, and the self-assembled hydrogels are able to recover from mechanical breakdowns. AFM images show that the elasticity is attributed to a network nanostructure consisting of fibrous self-assemblies. The hydrogels are promising for a variety of possible biomedical applications, including drug delivery.