Formation of a Tree having a Low Lignin Content

Received 30 September 2001/ Accepted in revised form 26 October 2001     

Chloroplast DNA variation inDesmodium subgenusPodocarpium (Leguminosae): Infrageneric phylogeny and infraspecific variations

Chloroplast DNA (cpDNA) restriction site variation was examined in five species ofDesmodium subgenusPodocarpium (Leguminosae; Papilionoideae; Desmodieae). Twenty four phylogenetically informative cpDNA mutations were scored. The cladistic analysis of characters based on the 24 mutations resulted in the most parsimonious tree which supports the monophyly of the subgenus.Desmodium elegans of subgenusDollinera was the sister group of subgenusPodocarpium in this tree. The groupings obtained from the cpDNA characters were consistent with the present infrageneric classification system for the subgenus except for the infraspecific taxa ofD. podocarpum. Three groups withinD. podocarpum, which were incongruent with the infraspecific classification of the species, were distinguished by a total of four site mutations. The first group consisted of subsp.podocarpum, subsp.fallax, and subsp.oxyphyllum var.oxyphyllum; the second subsp.oxyphyllum var.oxyphyllum; and the last subsp.oxyphyllum var.oxyphyllum and var.mandshuricum.     

Analysis of urinary organic acids by liquid chromatography—atmospheric pressure chemical ionization mass spectrometry

We developed a new method for the rapid determination of urinary organic acids using liquid chromatography—atmospheric pressure chemical ionization mass spectrometry. Mass spectra of authentic organic acids obtained in the negative-ion mode showed intense [M − H]⁻ ions with some fragment ions. Urine samples of patients with methylmalonic aciduria, ornithine transcarbamylase deficiency, and phenylketonuria were extracted using anion-exchange columns. The mass chromatograms of the extracts showed some dominant peaks of abnormal metabolites characteristic of each disorder. This is a useful method for the analysis of urinary organic acids for the diagnosis of organic aciduria, because the sample preparation is simple.     

Giant lysosomes in the renal proximal tubules--a morphological characteristic of DBA/2 and DBA/1 mouse kidneys.

The DBA/2Cr mouse is characterized by the presence of giant lysosomes located in the proximal convoluted tubules of males and proximal straight tubules of females. However, it remains unclear whether these giant lysosomes in the proximal tubules are characteristic of DBA/2Cr specifically, or are common to other DBA/2 substrains and DBA/1. The present study investigated the morphology of kidneys from DBA/2CrSlc, DBA/2JJcl, DBA/2NCrj and DBA/1JNCrj mice of both sexes. Giant lysosomes in the renal proximal tubules were found to represent common morphological characteristic of both DBA/2 and DBA/1JN.     

Control of the rate of phosphocreatine resynthesis after exercise in trained and untrained human quadriceps muscles

We examined the effect of differences in exercise intensity on the time constant (t _c) of phosphocreatine (PCr) resynthesis after exercise and the relationships betweent _c and maximal oxygen uptake (VO_2max) in endurance-trained runners (n = 5) and untrained controls (n = 7) (average VO_2max = 66.2 and 52.0 ml · min^–1 · kg^–1, respectively). To measure the metabolism of the quadriceps muscle using phosphorus nuclear magnetic resonance spectroscopy, we developed a device which allowed knee extension exercise inside a magnet. All the subjects performed four types of exercise: light, moderate, severe and exhausting. The end-exercise PCr: [PCr + inorganic phosphate (P_i)] ratio decreased significantly with the increase in the exercise intensity (P < 0.01). Although there was little difference in the end-exercise pH, adenosine diphosphate concentration ([ADP]) and the lowest intracellular pH during recovery between light and moderate exercise, significant changes were found at the two higher intensities (P < 0.01). These changes for runners were smaller than those for the controls (P < 0.05). The _c remained constant after light and moderate exercise and then lengthened in proportion to the increase in intensity (P < 0.05). The runners had a lowert _c at the same PCr and pH than the controls, particularly at the higher intensity (P < 0.05). There was a significant correlation betweent _c and [ADP] in light exercise and betweent _c and both end-exercise PCr and pH in severe and exhausting exercise (P < 0.05). The threshold of changes in pH andt _c was a PCr: (PCr + P_i) ratio of 0.5. There was a significant negative correlation between the VO_2max andt _c after all levels of exercise (P<0.05).However, in the controls a significant correlation was found in only light and moderate exercise (P < 0.05). These findings suggest the validity of the use oft _c at an end-exercise PCr:(PCr + P_i) ratio of more than 0.5 as a stable index of muscle oxidative capacity and the correlation between local and general aerobic capacity. Moreover, endurance-trained runners are characterized by the faster PCr resynthesis at the same PCr and intracellular pH.     

Studies on the heterotropic interaction of hemoglobin. I. Mass spectrometric method for determination of the pKa of the beta-146 histidine residue in human hemoglobin.

A mass spectrometric method was developed to determine pH-dependent hydrogen-deuterium exchange at the C-2 position of the imidazole ring of histidine, after converting the amino acid to the methylthiohydantoin derivative. The amount of deuterium exchange in N-acetyl-histidine estimated by the present method was confirmed to be in good agreement with that determined by NMR spectrometry. N-Acetylhistidine was deuterated at various pH's. From the amount of deuterium exchange, a pseudo-first order rate constant (kpsi) was calculated. A pKa value of 7.2 for the amino acid was obtained from the relation between kpsi and pH. This method was applied to estimate the pKa value of beta-146 histidine in human hemoglobin. Human hemoglobin deuterated at various pH's was digested with carboxypeptidase A [EC 3.4.12.2] to release the beta-146 histidine. The amount of deuterium exchange in the isolated histidine was determined to obtain kpsi. From these measurements pKa values of 7.0 for the histidine in oxyhemoglobin and of 8.2 for that in deoxyhemoglobin were found at 36.5 degrees, respectively.     

Anti-pituitary antibodies in patients with hypopituitarism and their families: longitudinal observation.

In an attempt to investigate the clinical significance of anti-pituitary antibodies in patients with hypopituitarism, anti-pituitary antibody in plasma was examined in 10 such patients (7 cases of isolated ACTH deficiency, 1 of partial hypopituitarism, and 2 of Sheehan's syndrome), on two or three occasions with an interval of more than 6 months (longitudinal study). In a total of 16 relatives of these 4 patients (2 cases of Sheehan's syndrome, one in each of partial hypopituitarism and isolated ACTH deficiency) and one patient not involved in the longitudinal study, anti-pituitary antibodies were also examined (family study). Anti-pituitary antibodies reacting with rat pituitary cytoplasmic antigens (pituitary cell antibodies: PCA) and pituitary cell surface antibodies (PCSA) reacting with GH3 cells and/or AtT-20 cells were measured with indirect immunofluorescence. The longitudinal study revealed the disappearance of antibodies in 3 patients, 2 PCA positive and one both PCA and PCSA positive. In 3 patients, altered antibody titers or a newly appearing antibody were found during the follow-up period. In 4 patients, the pituitary antibodies were negative during the follow-up periods. Of 16 family members studied, positive PCA was found in 3 members (2 in the families of patients with PCA positive Sheehan's syndrome, and 1 in the family of the patients with PCA positive partial hypopituitarism). Positive PCSA was found in 4 members (one in each of families of patients with partial hypopituitarism and isolated ACTH deficiency and of two cases of Sheehan's syndrome), and weakly positive PCSA was found in one family member of a patients with PCA positive Sheehan's syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)     

<Emphasis Type="Italic">Bruguiera hainesii</Emphasis>, a critically endangered mangrove species,is a hybrid between <Emphasis Type="Italic">B. cylindrica</Emphasis> and <Emphasis Type="Italic">B. gymnorhiza</Emphasis> (Rhizophoraceae)

Bruguiera hainesii (Rhizophoraceae) is one of the two Critically Endangered mangrove species listed in the IUCN Red List of Threatened Species. Although the species is vulnerable to extinction, its genetic diversity and the evolutionary relationships with other Bruguiera species are not well understood. Also, intermediate morphological characters imply that the species might be of hybrid origin. To clarify the genetic relationship between B. hainesii and other Bruguiera species, we conducted molecular analyses including all six Bruguiera species using DNA sequences of two nuclear genes (CesA and UNK) and three chloroplast regions (intergenic spacer regions of trnL-trnF, trnS-trnG and atpB-rbcL). For nuclear DNA markers, all nine B. hainesii samples from five populations were heterozygous at both loci, with one allele was shared with B. cylindrica, and the other with B. gymnorhiza. For chloroplast DNA markers, the two haplotypes found in B. hainesii were shared only by B. cylindrica. These results suggested that B. hainesii is a hybrid between B. cylindrica as the maternal parent and B. gymnorhiza as the paternal one. Furthermore, chloroplast DNA haplotypes found in B. hainesii suggest that hybridization has occurred independently in regions where the distribution ranges of the parental species meet. As the IUCN Red List of Threatened Species currently excludes hybrids (except for apomictic plant hybrids), the conservation status of B. hainesii should be reconsidered.     

Distinct roles of TIR and non-TIR regions in the subcellular localization and signaling properties of MyD88

MyD88 is a cytoplasmic adaptor protein that is critical for Toll-like receptor (TLR) signaling. The subcellular localization of MyD88 is characterized as large condensed forms in the cytoplasm. The mechanism and significance of this localization with respect to the signaling function, however, are currently unknown. Here, we demonstrate that MyD88 localization depends on the entire non-TIR region and that the correct cellular targeting of MyD88 is indispensable for its signaling function. The Toll-interleukin I receptor-resistance (TIR) domain does not determine the subcellular localization, but it mediates interaction with specific TLRs. These findings reveal distinct roles for the TIR and non-TIR regions in the subcellular localization and signaling properties of MyD88.     

The extremely conserved C-terminal region of Reelin is not necessary for secretion but is required for efficient activation of downstream signaling

Reelin is a very large secreted glycoprotein essential for correct development of the mammalian brain. It is also implicated in higher functions and diseases of human brain. However, whether or not secretion of Reelin is regulated and how Reelin transmits signals remain largely unknown. Reelin protein is composed of an N-terminal F-spondin-like domain, Reelin repeats, and a short and highly basic C-terminal region (CTR). The primary sequence of CTR is almost completely conserved among vertebrates except fishes, indicating its importance. A prevailing idea regarding the function of CTR is that it is required for the secretion of Reelin, although this remains unproven. Here we aimed to clarify the function of Reelin CTR. Neither deleting most of CTR nor replacing CTR with unrelated amino acids affected secretion efficiency, indicating that CTR is not absolutely required for the secretion of Reelin. We also found that Reelin mutants without CTR were less potent in activating the downstream signaling in cortical neurons. Although these mutants were able to bind to the Reelin receptor ectodomain as efficiently as wild-type Reelin, quite interestingly, their ability to bind to the isolated cell membrane bearing Reelin receptors or receptor-expressing cells (including cortical neurons) was much weaker than that of wild-type Reelin. Therefore, it is concluded that the CTR of Reelin is not essential for its secretion but is required for efficient activation of downstream signaling events, presumably via binding to an unidentified "co-receptor" molecule(s) on the cell membrane.