Stand-scale transpiration estimates in a Moso bamboo forest: (I) Applicability of sap flux measurements

The applicability of sap flux (F_d) measurements to bamboo forests has not been studied. This study was undertaken to establish an optimal and effective design for stand-scale transpiration (E) estimates in a Moso bamboo forest. To this aim, we validated F_d measurements in Moso bamboos in a cut bamboo experiment. In addition, we analyzed how sample sizes affect the reliability of E estimates calculated from F_d and conducting culm area (A_{S_b}). In the cut bamboo experiments, we found that F_d measurement using a 10 mm probe was a valid means of determining the water-use behavior of a Moso bamboo, although a specific correction was needed. Furthermore, we calculated E from stand A_{S_b} (A_{S_stand}) and mean stand F_d (J_S). Employing Monte Carlo analysis, we examined potential errors associated with sample size in E, A_{S_stand}, and J_S using an original dataset with A_{S_b} and F_d measured for 40 and 16 individuals, respectively. Consequently, we determined the optimal sample size for both A_{S_stand} and J_S estimates as 11. The optimal sample sizes for J_S were almost the same under different vapor pressure deficit and soil moisture conditions. The optimal sample size for J_S at the study site was less than that of a coniferous plantation in the same region probably owing to small individual-to-individual variations in sap flux in the Moso bamboo forest. Our study concludes that sap flux measurements are an applicable technique for assessing water use in Moso bamboo forests.     

Effects of duration and combination of drought and flood conditions on leaf photosynthesis,growth and sugar content in sugarcane

Global climate change will result in extreme environments, such as droughts and floods. We investigated the individual and combined effects of droughts and floods of varying duration on sugarcane (Saccharum spp.) growth using a pot experiment under glasshouse conditions with the following six treatments: drought for 15 d, prolonged drought for 30 d, flood for 15 d, prolonged flood for 30 d, short flood followed by prolonged drought, and prolonged flood followed by prolonged drought. Plants that were subjected to drought conditions, including drought after a flood, had reduced CO₂ assimilation (through stomatal closure) and leaf areas, whereas flood conditions showed no effect. During flooding, some roots died, and adventitious roots with well-developed aerenchyma appeared from the submerged nodes. At the time of harvest, there were no significant differences in stem fresh weight, sucrose content, or sugar yield between the treatments. However, ion content analysis revealed that flood conditions caused an accumulation of sodium in the bottom of stems and adventitious roots. Therefore, under flood conditions, plants may develop adventitious roots, which may offset the negative effects of root death, helping them to maintain their growth and yield.     

Flow cytometric analysis of bronchoalveolar lavage fluid immune dynamics in calves

Understanding the immune dynamics in the respiratory mucosa of calves is necessary for a good management of bovine respiratory disease. Immune dynamics in the respiratory mucosa in humans and experimental animals has been assessed by flow cytometric analysis of bronchoalveolar lavage fluid (BALF); however, few reports have addressed this subject in calves. The aim of this study was to establish a universal method to analyze bronchoalveolar lavage fluid (BALF) by flow cytometry and to obtain basic knowledge of bovine respiratory mucosal immune dynamics. We investigated the immune cell populations in BALF and evaluated the surface antigen expression of alveolar macrophages in calves using flow cytometer. To further analyze the surface antigen variation observed in alveolar macrophages in detail, stimulation assays were performed in vitro. BALF cells were separated into three distinct populations based on their light scatter plot, which were considered to be macrophages, lymphocytes, and neutrophils. In most individuals, most of the BALF immune cells were alveolar macrophages, but an increased proportion of lymphocytes and neutrophils was observed in some individuals. Analysis of each surface antigen expression in alveolar macrophages showed that CD21 and MHC class II expression changed in response to changes in the leukocyte population. Moreover, when alveolar macrophages were stimulated with interferon-γ in vitro, the expression of CD21 was drastically reduced and MHC class II was increased, suggesting that functional changes in alveolar macrophages themselves are involved in the immune dynamics.     

Development of late-bolting F<Subscript>1</Subscript> hybrids of Chinese cabbage (<Emphasis Type="Italic">Brassica rapa</Emphasis> L.) allowing early spring cultivation without heating

We developed new F₁ hybrids of Chinese cabbage (Brassica rapa L. ssp. pekinensis) that allow cultivation earlier in spring without heating by introducing extremely late-bolting alleles at two homologs of the flowering repressor Flowering Locus C (BrFLC2 and BrFLC3) from non-heading ‘Leafy Green Parental Line No. 2’. These new F₁ hybrids were produced by the following four steps. First, the extremely late bolting selected lines were developed. These selected lines headed in spring after overwintering cultivation, whereas the conventional F₁ cultivars flowered. Secondly, an investigation of the three plantings showed that our F₁ hybrids formed heads when seeds were sown from mid-February to early March, whereas the conventional F₁ cultivar did not form heads because of premature bolting. Thirdly, we identified some F₁ hybrids with extremely late bolting during early spring cultivation in an investigation of many F₁ hybrids. Finally, based on an investigation across four cold regions for 2 years, we compared the commercialization rate, defined as the proportion of plants greater than 2000 g in weight and with a flowering stalk less than 10 cm long. Then we identified a F₁ of MS02 × 12-04 which had a high commercialization rate on average (92%), whereas the rates of three conventional F₁ cultivars were only 0–2%. In the near future, these F₁ hybrids will be valuable late-bolting cultivars despite climate change, permitting stable cultivation and harvest over wide regions.     

Identification of antioxidative flavonols and anthocyanins in Sicana odorifera fruit peel

Ten flavonols and three anthocyanins were identified in the fruit peel of melo?n de olor (Sicana odorifera), and their structures were established by spectrometric and spectroscopic (ESI-MS and NMR) techniques. One of the identified flavonols, quercetin 3-O-(6'-O-malonyl)-β-D-glucopyranoside 4'-O-β-D-glucopyranoside, has not been reported before in the plant kingdom. Although quercetin-3-O-α-L-rhamnopyranosyl-(1→6)-β-d-glucopyranoside-4'-O-β-D-glucopyranoside had been reported before in literature and structure elucidation was done by comparison of NMR data with published data, to the best of our knowledge complete 1D and 2D NMR data have not been not delineated so far. Moreover, the antioxidant activity of pure compounds was measured by ABTS assay. It was established that quercetin 3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside, quercetin-3-O-(6'-malonyl)-glucopyranoside, quercetin-3-O-β-D-glucopyranoside, and quercetin-3-O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside-4'-O-β-D-glucopyranoside contribute significantly to the antioxidant activity exhibited by the fruit peel methanolic extract.     

A Monitoring System for Green Fluorescence Protein Gene-transformed Fusarium oxysporum in Melon Seedlings

Using melon seedlings at the cotyledon stage and genetically marked fungi, a system for monitoring pathogenic and nonpathogenic Fusarium oxysporum was devised in the present study. Protoplasts were prepared from three formae speciales (melonis, radicis-lycopersici and fragariae )of F. oxysporum and transformed with a synthetic gene for green fluorescence protein. Transformants were primarily isolated in the presence of hygromycin B and then screened by the emission of bright green fluorescence. Roots of melon seedlings were inoculated with fluorescing microconidia of these fungi, and fungal infection behavior was traced. Using fluorescence microscopy, we directly observed not only the fungus at the root surface, but also the mycelia elongating in the trachea of roots. Both pathogenic and nonpathogenic fungi germinated and hyphae elongated superficially on the surface of root. Only pathogenic fungi caused root necrosis at the inoculation site. Hyphae grew within the stem to induce constriction or cracking of lower hypocotyls, then causing wilting of the seedlings. Infection behavior of genetically marked pathogenic and nonpathogenic F. oxysporum could be successfully monitored after inoculation of cotyledons of seedlings. Received 6 June 2001/ Accepted in revised form 3 August 2001     

Urinary corticoid to creatinine ratios using IMMULITE 2000 XPi for diagnosis of canine hypercortisolism

The urinary corticoid to creatinine ratio (UCCR) is one of the most commonly used screening tests for canine hypercortisolism (HC). In this study, a reference interval was established for UCCR using IMMULITE 2000 XPi, the latest chemiluminescence enzyme immunoassay. The diagnostic performance of this method for UCCR in canine HC was also evaluated. The median UCCR was 1.06 × 10⁻⁵ (range: 0.28–2.49) for 58 healthy dogs, and an upper reference limit of 1.98 × 10⁻⁵ (90% confidence interval: 1.76–2.15) was determined. The median UCCR in the 12 dogs with HC (7.38 × 10⁻⁵, range 1.86–29.98) was significantly higher than that in the 16 dogs with mimic-HC (1.59 × 10⁻⁵, range 0.47–3.42, P<0.001). The area under the curve for UCCR to differentiate HC dogs from mimic-HC dogs was 0.971, with a sensitivity of 91.7% and specificity of 100% when the cut-off value was set at 3.77 × 10⁻⁵. The UCCR of 16 paired urine samples collected at home and in hospital showed that the UCCR of samples collected in the hospital was significantly higher than that of samples collected at home (mean difference 3.30 × 10⁻⁵, 95% confidence interval: 0.70–5.90, P=0.001). In summary, we established the upper reference limit for UCCR using IMMULITE 2000 XPi in dogs and confirmed that UCCR is a useful diagnostic test for HC in dogs if urine samples are collected at home.     

Involvement of the fas ligand and fas system in apoptosis induction of mouse uterine natural killer cells

Uterine natural killer (uNK) cells in the pregnant uterus are known to be associated with the normal development of the placenta. In the mouse pregnant uterus, many uNK cells exist during mid pregnancy, although they show a sudden decrease during late pregnancy and almost disappear before delivery. Our previous study indicated that uNK cells showed clear apoptotic morphology during late pregnancy. Therefore, the present study was carried out to define the involvement of Fas ligand (FasL) and Fas in apoptosis induction of uNK cells. Immunohistochemical analyses revealed that uNK cells expressed FasL in the cytoplasmic granules and Fas on the cell membrane during late pregnancy. In lpr/lpr mice, which genetically lack Fas, many uNK cells were clearly observed during late pregnancy compared with wild-type mice, and moreover uNK cells still existed at day-18 of pregnancy, although there were few in wild-type mice during the same period. In the experiment of in vitro culture, uNK cells derived from wild-type placenta showed chromatin condensation and DNA fragmentation frequently following the anti-Fas antibody treatment, as compared with the control. From these results, it is suggested that FasL and Fas-dependent apoptosis regulates cell appearance of uNK cells in the mouse pregnant uterus.     

Evaluation of hepatosplanchnic circulation and intestinal oxygenation in dogs with a condition that mimicked septic shock induced by continuous infusion of a low dose of lipopolysaccharide

OBJECTIVE: To determine whether continuous infusion of a low dose of lipopolysaccharide (LPS) to induce a condition mimicking septic shock in dogs would affect systemic and hepatosplanchnic circulation and oxygenation. ANIMALS: 12 healthy adult Beagles. PROCEDURE: Dogs received a low dose of LPS (Escherichia coli O55:B5) by continuous IV infusion at a rate of 1 microg/kg/h for 8 hours. Systemic hemodynamics; systemic oxygenation; blood flow in the cranial mesenteric artery, common hepatic artery, and portal vein; intestinal and hepatic tissue blood flow; mesenteric oxygenation; and intramucosal Pco2 were examined before and at selected time points after onset of the LPS infusion. RESULTS: After onset of the LPS infusion, cardiac index increased and mean arterial pressure (MAP) and systemic vascular resistance decreased, which is characteristic of the hyperdynamic state in septic patients. Hepatosplanchnic blood flow increased during the hyperdynamic state. Intestinal Pco2 was increased even when blood flows increased. During the latter half of the experimental period, MAP was maintained but hepatosplanchnic blood flows decreased and intestinal Pco2 increased further. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of the results suggested that hepatosplanchnic blood flow enters the hyperdynamic state during the early stages of sepsis and that intestinal tissue oxygenation is threatened even when hepatosplanchnic blood flow is increased or maintained. Hence, improvement of hepatosplanchnic circulation and intestinal tissue oxygenation is important in dogs with clinical evidence of a septic condition.