Stress responses in Salix gracilistyla cuttings subjected to repetitive alternate flooding and drought

To determine the tolerance of Salix gracilistyla to repetitive alternate flooding and drought, we measured leaf stomatal conductance, pre-dawn water potential, osmotic adjustment, and biomass production under greenhouse conditions. We used a control and nine crossed treatments (F1-D1–F3-D3) in which we combined 1-, 2-, or 3-week floodings (F) and droughts (D). Leaf stomatal conductance was lowest in 3 weeks of flooding or drought when the preceding event (flood or drought) was also of a 3-week duration. Leaf pre-dawn water potential was reduced in 3 weeks of drought when preceded by 2 or 3 weeks of flooding. Cuttings had slight osmotic adjustments in repetitions of long floodings and droughts. During longer durations of drought in crossed experiments, plants had low root and shoot mass, few hypertrophic lenticels, and reduced leaf mass; when flooding duration increased in crossed experiments, root mass was reduced, there were more hypertrophic lenticels, and the leaf area was reduced. Cuttings achieved stress tolerance by inhibition of transpiration, osmotic adjustment, reduction of transpiration area, and development of hypertrophic lenticels. Stress tolerance was weak when repetitive 2- or 3-week floodings were combined with 3-week droughts. The duration of flooding and drought periods under which S. gracilistyla achieves stress tolerance may be critical in determining distributions along riverbanks.     

Narcolepsy in orexin knockout mice: molecular genetics of sleep regulation.

Neurons containing the neuropeptide orexin (hypocretin) are located exclusively in the lateral hypothalamus and send axons to numerous regions throughout the central nervous system, including the major nuclei implicated in sleep regulation. Here, we report that, by behavioral and electroencephalographic criteria, orexin knockout mice exhibit a phenotype strikingly similar to human narcolepsy patients, as well as canarc-1 mutant dogs, the only known monogenic model of narcolepsy. Moreover, modafinil, an anti-narcoleptic drug with ill-defined mechanisms of action, activates orexin-containing neurons. We propose that orexin regulates sleep/wakefulness states, and that orexin knockout mice are a model of human narcolepsy, a disorder characterized primarily by rapid eye movement (REM) sleep dysregulation.     

Growth responses of <Emphasis Type="Italic">Salix gracilistyla</Emphasis> cuttings to a range of substrate moisture and oxygen availability

The objective of this study is to determine the effects of substrate moisture and oxygen availability on growth traits of Salix gracilistyla Miquel, which colonizes gravel bars along rivers, the shoot growth schedule, biomass production, and resource allocation were examined under greenhouse conditions. We used four treatments representing a range of substrate moisture and oxygen availability: drought (D), flooding with standing water (FS), flooding with running water (FR), and control without drought or flooding (C). Cuttings in D stopped flushing and had low biomass production, reduced total leaf mass, and small leaves. Under anaerobic conditions, cuttings in FS stopped flushing and had low biomass production, small root biomass, low biomass allocation to roots, shallow roots, high biomass allocation to hypertrophied lenticels, and a few small, thick leaves. Under aerobic conditions, cuttings in FR showed continuous branch elongation and flushing, large biomass production, and large leaf biomass, similar to cuttings in C, in addition to low allocation to hypertrophied lenticels and many large leaves. The growth of cuttings was not inhibited by flooding of the roots throughout the experiment unless the conditions were anaerobic. Thus, cuttings respond to water stress under low moisture conditions by reducing the transpiration area and respond to flooding under low oxygen conditions by high allocation to hypertrophied lenticels and reduced transpiration area. Plasticity in the shoot growth schedule, biomass production, and resource allocation according to moisture conditions and the ability to develop hypertrophied lenticels upon flooding allow S. gracilistyla to colonize sites in which both desiccation and flooding occur.     

Species-identification and antimicrobial susceptibility tests by the fully automated RAISUS using an early-harvested cell suspension]

We evaluated the usefulness of an early-harvested bacterial cell suspension to the fully automated RAISUS (Nissui Pharmaceuticals Co., Ltd., Tokyo) to provide the results of species-identification and antimicrobial susceptibility testings within a day after overnight-incubation of the primary cultures. A single, well-separated colony appeared on the primary culture plate was transferred onto a blood agar or chocolate agar plates, then incubated for 3 to 6 hours. The cell suspension to the RAISUS was properly prepared to the McFarland 0.5 turbidity from the early-harvested bacterial cells. When the five ATCC reference strains, consisting of Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Streptococcus pneumoniae ATCC 49619, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853, were repeatedly tested for the species-identification, all the identification results were acceptable. Antimicrobial susceptibility tests were evaluated with the above five strains and Haemophilus influenzae ATCC 49247. The results obtained indicated that the most susceptibility test results were comparable to those MICs obtained by the standard test procedure, but some strains, in particular, H. influenzae and P. aeruginosa gave significantly discrepant MICs for certain antimicrobial agents. The significant discrepancy in MIC determinations regarded the difference of viable cell concentrations in the cell suspension prepared respectively. Through the analysis of laboratory workflow, it became to apparent that 18S to 20S of the tests were completed by 5:00 p.m., and it required to wait until 3:00 a.m. to complete 90S of the tests. With these results, the early-harvested bacterial cell suspension is applicable to species-identification by RAISUS, but it is necessary to adjust viable cell concentrations to antimicrobial susceptibility test. Also, it is urgent to reconstitute a daily workflow to improve the rapidity of RAISUS test function.     

Cardiomyocyte-specific endothelin A receptor knockout mice have normal cardiac function and an unaltered hypertrophic response to angiotensin II and isoproterenol

Even though endothelin is recognized as an important vasoregulatory molecule, the roles of endothelin receptors in specific cell types are not yet fully understood. Mice with a null mutation in endothelin A receptor gene (ET(A)) or in the gene of its ligand (endothelin 1) die neonatally due to craniofacial and cardiac abnormalities. This early lethality has in the past hindered studies on the role of endothelin in cardiovascular physiology and pathophysiology. To overcome this obstacle, we utilized the cre/loxP technology to generate mice in which the ET(A) gene could be deleted specifically in cardiomyocytes. The cre recombinase transgene driven by the alpha-myosin heavy-chain promoter deleted the floxed ET(A) allele specifically in the hearts of these mice, resulting in a 78% reduction in cardiac ET(A) mRNA level compared to wild-type controls. Cardiomyocyte-specific ET(A) knockout animals are viable and exhibit normal growth, cardiac anatomy, and cardiac contractility, as assessed by echocardiography. In addition, these animals exhibit hypertrophic and contractile responses to 10-day infusion of angiotensin II or isoproterenol similar to those observed in control animals. These results indicate that in adult mice cardiac ET(A) receptors are not necessary for either baseline cardiac function or stress-induced response to angiotensin II or isoproterenol.     

Novel distribution of adrenomedullin-immunoreactive cells in human tissues

Adrenomedullin (AM) is a novel hypotensive and vasodilator peptide. We previously examined the localization of AM in human, rat, and porcine tissues using a polyclonal antibody against synthetic human AM[40–52]. We demonstrated that AM is widely distributed in the endocrine and neuroendocrine systems, but not in the heart, kidney, or blood vessels, although high levels of AM mRNA were detected in the latter tissues. In this study, we further investigated the distribution of AM by using two newly developed monoclonal antibodies against synthetic human AM peptides, [12–25] and [46–52]. AM immunoreactivity was observed in cardiac myocytes, vascular smooth muscle cells, endothelial cells, and renal distal and collecting tubules. In addition, AM-immunoreactive (IR) cells were found in mucosal and glandular epithelia of the digestive, respiratory, and reproductive systems, as well as the endocrine and neuroendocrine systems. These findings indicate that AM-IR cells are more widely distributed in human tissues and suggest that AM might play multiple biological roles in humans. Accepted: 7 June 1999     

Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis

We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP) was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues and to identify a population of progenitor cells whose significance would have to be further investigated.     

Acid triacyglycerol lipase inhibitor in chicken plasma: purification and properties

1. Acid triacylglycerol lipase inhibitor was highly purified from chicken plasma by ammonium sulfate fractionation (0.6-1 saturation) followed by successive chromatographies on Hydroxyapatite, Blue-Cellulofine, Phenyl-Sepharose and Cellulofine GCL-2000 columns, and isoelectric focusing. 2. The lipase inhibitor showed its inhibitory action on triacylglycerol lipases in chicken erythrocytes ghosts and in chicken liver lysosome, but did not on pancreatic lipase, Rhizopus arrhizus lipase, or wheat germ lipase. 3. The inhibitor showed its molecular weight of 32,000 by Cellulofine GCL-2000 gel filtration. The inhibitor showed some heterogeneity on isoelectric focusing, and the main band had a pI of 5.10. 4. The lipase inhibitor did not show any inhibitory action on trypsin or chymotrypsin.     

红背山麻杆叶的化学成分研究(Ⅱ)——黄酮和苯乙醇苷类化合物

采用80％丙酮提取物的水萃取部位,利用凝胶、MCI、反相碳18、及 Toyopearl Butyl-650C 柱色谱进行分离纯化得到7个黄酮和3个苯乙醇苷类化合物。根据化合物的波谱数据分析鉴定为槲皮素(1)、槲皮苷(2)、异懈皮苷(3)、芦丁(4)、异牡荆素(5)、牡荆素(6)、木犀草素-7-O-α-L-鼠李糖(1→6)-β-D-葡萄糖苷(7)、2-phenethylβ-D-glucoside(8)、icariside D1(9)、2-苯乙基-D-芸香甙(10)。其中化合物1-3、5-6、8-10为首次从本属植物中分离得到。