Expression and function of Slit1alpha, a novel alternative splicing product for slit1

Slits are large molecular and extracellular glycoproteins that may function as chemorepellents in axon guidance and neural cell migration. The heterogeneity of the mRNA for slit has been described. Its variants indicate considerable potential for alternative splicing, resulting in the generation of multiple protein isoforms. We examined the regions in which these isoforms are expressed, and identified the highest expression of a splicing product for slit1 in rat brain rather than in other organs. The splicing product, Slit1alpha, arises through alternative splicing at the C-terminus of Slit1, causing defects in the cysteine knot domain. We show that slit1alpha exists in the hippocampus and cerebral cortex in rat brain by in situ hybridization, and that it acts as a chemorepellent in olfactory bulb axon guidance in vitro. These findings suggest that Slit1alpha is an active Slit1 protein specific in the vertebrate nervous system.     

On the origin of six-rowed barley with brittle rachis, agriocrithon [Hordeum vulgare ssp. vulgare f. agriocrithon (Aberg) Bowd.], based on a DNA marker closely linked to the vrs1 (six-row gene) locus

The origin of six-rowed cultivated barley has been revealed to be more complex since the discovery of agriocrithon, a six-rowed barley with brittle rachis. The present study investigates whether such six-rowed brittle barley is wild or hybrid in nature, by analyzing genetic diversity at the cMWG699 marker locus, which is closely linked to the vrs1 (six-row gene) locus. DNA sequence analysis for 42 accessions showed only three types in six-rowed brittle barleys; in contrast, nine sequence types were found in ten wild barleys, ssp. spontaneum, in our previous study. Nucleotide diversities for the six-rowed brittle barley were 2.8–4.5 times lower than that for the ssp. spontaneum at this marker locus. The three sequence types found in the six-rowed brittle barley also appeared in the six-rowed cultivated barley. A cross-allelism test confirmed that the six-rowed character of the six-rowed brittle barley was controlled by the vrs1 locus. The nucleotide diversity and genealogy demonstrated that f. agriocrithon does not have the same level of diversity as found in wild barley, ssp. spontaneum. Consequently, f. agriocrithon does not appear to represent genuinely wild populations, but more probably originated from hybridization between ssp. spontaneum and six-rowed cultivated barley.     

Association between high-sensitivity cardiac troponin T and future cardiovascular incidence in a general Japanese population: results from the Tohoku medical megabank project

Purpose: Elevation of high-sensitivity cardiac troponin T (hs-cTnT) is associated with an increased risk of cardiovascular disease (CVD). This study determined whether hs-cTnT was detectable with N-terminal pro-b-type natriuretic peptide (NT-proBNP) and related to CV risk factors in a general Japanese population.

Materials and methods: The Tohoku Medical Megabank Organization pooled individual participant data for a population-based cohort study in the Iwate prefecture (n?=?30,193, age = 60.2?±?11.5?year).

Results: Hs-cTnT levels were higher in participants with hypertension, diabetes mellitus than in participants without these conditions (all ps < 0.001). Logistic regression analysis demonstrated that NT-proBNP was strongly associated with elevation of hs-cTnT (OR = 3.35, 95% CI = 2.90–3.89, p?<?0.001). The receiver operating characteristic curve analysis showed that hs-cTnT was one of useful biomarker for the differentiation of high risk for CVD (the Suita score ≥ 56) from a general population. Logistic regression analysis demonstrated hs-cTnT levels were related to the CVD high risk group (OR = 2.67, 95% CI = 2.28–3.14, p?<?0.001).

Conclusions: Hs-cTnT levels are associated with elevation of NT-proBNP and high Suita score, which suggests that elevated hs-cTnT is related to subclinical myocardial damage and indicates CV risk.     

Erythropoietin affords additional cardioprotection to preconditioned hearts by enhanced phosphorylation of glycogen synthase kinase-3 beta

The aim of this study was to determine whether erythropoietin (EPO) affords additional cardioprotection to the preconditioned myocardium by enhanced phosphorylation of Akt, STAT3, or glycogen synthase kinase-3beta (GSK-3 beta). Preconditioning (PC) with 5-min ischemia/5-min reperfusion and EPO (5,000 U/kg iv) reduced infarct size (as % of area at risk, %IS/AR) after 20-min ischemia in rat hearts in situ from 56.5 +/- 1.8% to 25.2 +/- 2.1% and to 36.2 +/- 2.8%, respectively. PC-induced protection was significantly inhibited by a protein kinase C inhibitor, chelerythrine (5 mg/kg), and slightly blunted by a phosphatidylinositol-3-kinase inhibitor, wortmannin (15 microg/kg). The opposite pattern of inhibition was observed for EPO-induced protection. The combination of PC and EPO further reduced %IS/AR to 8.9 +/- 1.9%, and this protection was inhibited by chelerythrine and wortmannin. The additive effects of PC and EPO on infarct size were mirrored by their effects on the level of phosphorylated GSK-3 beta at 5 min after reperfusion but not their effects on the level of phospho-Akt or phospho-STAT3. To mimic phosphorylation-induced inhibition of GSK-3 beta activity, SB-216763 (SB), a GSK-3 beta inhibitor, was administered before ischemia or 5 min before reperfusion. Infarct size was significantly reduced by preischemic injection (%IS/AR = 40.4 +/- 2.2% by 0.6 mg/kg SB and 34.0 +/- 1.8% by 1.2 mg/kg SB) and also by prereperfusion injection (%IS/AR = 32.0 +/- 2.0% by 1.2 mg/kg SB). These results suggest that EPO and PC afford additive infarct size-limiting effects by additive phosphorylation of GSK-3beta at the time of reperfusion by Akt-dependent and -independent mechanisms.     

Two new endemic species of Myrtaceae and an anatomical novelty from the Highlands of Brazil

Campomanesia cavalcantina Soares-Silva & Proen?a and Psidium ratterianum Proen?a & Soares-Silva (Myrtaceae), two new species from the Brazilian highlands are described and illustrated. Campomanesia cavalcantina is similar to Campomanesia eugenioides (Cambess.) D. Legrand var. eugenioides, but differs from this species in being an hemixyle, by the narrow to broadly elliptic-falcate leaves 1.7 – 4.6 times as long as wide with 8 – 15 lateral veins, by the less densely glandular leaves and flowers, and by the lanceolate, c. 7 mm long bracteoles which are persistent to young fruit stage. Psidium ratterianum appears to be most closely allied to P. australe Cambess. Both species share the hemixyle habit, similar leaf shape, leaf ratio and floral morphology. P. ratterianum differs from that species by its narrow, ascendant, strongly bullate leaves, bracteoles which are persistent in the fruit, expanded, funnel-shaped stigma and smaller, elliptic fruits. Anatomically, Psidium ratterianum differs from other species of Psidium, and from other new-world Myrtaceae (Tribe Myrteae), in that the leaves are amphistomatic, a character known to occur in the Australian genus Leptospermum.     

Interactions between Serum Vitamin D Levels and Vitamin D Receptor Gene FokI Polymorphisms for Renal Function in Patients with Type 2 Diabetes

Background

We aimed to examine associations among serum 25-hydroxyvitamin D (25OHD) levels, 1,25-dihyroxyvitamin D (1,25OHD) levels, vitamin D receptor (VDR) polymorphisms, and renal function based on estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes.

Methods

In a cross-sectional study of 410 patients, chronic kidney disease (CKD) stage assessed by eGFR was compared with 25OHD, 1,25OHD, and VDR FokI (rs10735810) polymorphisms by an ordered logistic regression model adjusted for the following confounders: disease duration, calendar month, use of angiotensin converting enzyme inhibitors/angiotensin receptor blockers or statins, and serum calcium, phosphate, and intact parathyroid hormone levels.

Results

1,25OHD levels, rather than 25OHD levels, showed seasonal oscillations; peak levels were seen from May to October and the lowest levels were seen from December to February. These findings were evident in patients with CKD stage 3∼5 but not stage 1∼2. eGFR was in direct proportion to both 25OHD and 1,25OHD levels (P<0.0001), but it had stronger linearity with 1,25OHD (r = 0.73) than 25OHD (r = 0.22) levels. Using multivariate analysis, 1,25OHD levels (P<0.001), but not 25OHD levels, were negatively associated with CKD stage. Although FokI polymorphisms by themselves showed no significant associations with CKD stage, a significant interaction between 1,25OHD and FokITT was observed (P = 0.008). The positive association between 1,25OHD and eGFR was steeper in FokICT and CC polymorphisms (r = 0.74) than FokITT polymorphisms (r = 0.65).

Conclusions

These results suggest that higher 1,25OHD levels may be associated with better CKD stages in patients with type 2 diabetes and that this association was modified by FokI polymorphisms.     

Cloning, sequence, and expression of a chitinase gene from a marine bacterium, Altermonas sp. strain O-7.

The gene encoding an extracellular chitinase from marine Alteromonas sp. strain O-7 was cloned in Escherichia coli JM109 by using pUC18. The chitinase produced was not secreted into the growth medium but accumulated in the periplasmic space. A chitinase-positive clone of E. coli produced two chitinases with different molecular weights from a single chitinase gene. These proteins showed almost the same enzymatic properties as the native chitinase of Alteromonas sp. strain O-7. The N-terminal sequences of the two enzymes were identical. The nucleotide sequence of the 3,394-bp SphI-HindIII fragment that included the chitinase gene was determined. A single open reading frame was found to encode a protein consisting of 820 amino acids with a molecular weight of 87,341. A putative ribosome-binding site, promoter, and signal sequence were identified. The deduced amino acid sequence of the cloned chitinase showed sequence homology with chitinases A (33.4%) and B (15.3%) from Serratia marcescens. Regardless of origin, the enzymes of the two bacteria isolated from marine and terrestrial environments had high homology, suggesting that these organisms evolved from a common ancestor.     

Phylogeny in the genus Hordeum based on nucleotide sequences closely linked to the vrs1 locus (row number of spikelets).

The phylogenetic relationship between four basic genomes designated H, I, Xa, and Xu in the genus Hordeum was studied using a nuclear DNA sequence. The sequence, cMWG699, is single copy in the H. vulgare genome, and tightly linked to the vrs1 locus which controls two- and six-rowed spikes. DNA fragments homologous to cMWG699 were amplified from diploid Hordeum species and the nucleotide sequences were determined. A phylogeny based on both base substitutions and an insertion-deletion event showed that the H- and Xa-genome groups are positioned in one monophyletic group indicating that the Xa-genome taxa should be included in the H-genome group. The large H-genome group is highly homogeneous. The I and Xu genomes are distinctly separated from H and Xa, and form sister groups. Another phylogeny pattern based on data excluding the insertion-deletion gave a result that the Xa genome forms a sister group to the H-genome group. The difference between the H and Xa genomes was affected only by a single base insertion-deletion event, thus the H and Xa genomes are likely to be closely related. The I and Xu genomes were again distinctly separated from the H and Xa genomes.     

Sprouting promotion by inhibitors of nucleic acid and protein synthesis in the bulbils of some herbaceous plants

The sprouting of immature bulbils of Laportea bulbifera andpartially dormant (in-sufficiently chilled) mature bulbils ofL. bulbifera, Elatostema involucratum and E. umbellatum waspromoted by inhibitors of nucleic acid and protein synthesis(8-azaguanine, 5-fluorouracil, 2-thiouracil, ethionine, canavaninesulfate, p-fluorophenylalanine and cycloheximide in Laporteaand 5-fluorouracil, cycloheximide and chloramphenicol in Elatostema).However, the sprouting of nondormant (chilled) mature bulbilsof L. bulbifera was not promoted, but slightly suppressed whenthese inhibitors (especially, 8-azaguanine, cycloheximide andchloramphenicol) were applied either during or after chillingtreatment These results suggest that the two counteracting systems,dormancy-inducing and -breaking which involve nucleic acid andprotein synthesis participate in the dormancy regulation. (Received December 2, 1977; )