Real-time [11C]methionine translocation in barley in relation to mugineic acid phytosiderophore biosynthesis

[11C]Methionine was supplied through barley roots and the 11C signal was followed for 90 min using a real-time imaging system (PETIS), with subsequent development of autoradiographic images of the whole plant. In all cases, [11C]methionine was first translocated to the 'discrimination center', the basal part of the shoot, and this part was most strongly labeled. Methionine absorbed by the roots of the plants was subsequently translocated to other parts of the plant. In Fe-deficient barley plants, a drastic reduction in [11C]methionine translocation from the roots to the shoot was observed, while a greater amount of 11C was found in the leaves of Fe-sufficient or methionine-pretreated Fe-deficient plants. Treatment of Fe-deficient plants with aminooxyacetic acid, an inhibitor of nicotianamine aminotransferase, increased the translocation of [11C]methionine to the shoot. The retention of exogenously supplied [11C]methionine in the roots of Fe-deficient barley indicates that the methionine is used in the biosynthesis of mugineic acid phytosiderophores in barley roots. This and the absence of methionine movement from shoots to the roots suggest that the mugineic acid precursor methionine originates in the roots of plants.     

Electrophysiological Studies of the Antrum Muscle Fibers of the Guinea Pig Stomach

The membrane potentials of single smooth muscle fibers of various regions of the stomach were measured, and do not differ from those measured in intestinal muscle. Spontaneous slow waves with superimposed spikes could be recorded from the longitudinal and circular muscle of the antrum. The development of tension was preceded by spikes but often tension appeared only when the slow waves were generated. Contracture in high K solution developed at a critical membrane potential of -42 mv. MnCl₂ blocked the spike generation, then lowered the amplitude of the slow wave. On the other hand, withdrawal of Na⁺, or addition of atropine and tetrodotoxin inhibited the generation of most of the slow waves but a spike could still be elicited by electrical stimulation. Prostigmine enhanced and prolonged the slow wave; acetylcholine depolarized the membrane without change in the frequency of the slow waves. Chronaxie for the spike generation in the longitudinal muscle of the antrum was 30 msec and conduction velocity was 1.2 cm/sec. The time constant of the foot of the propagated spike was 28 msec. The space constants measured from the longitudinal and circular muscles of the antrum were 1.1 mm and 1.4 mm, respectively.     

Seasonal changes of the at-sea distribution and food provisioning in rhinoceros auklets

Central-place foraging seabirds increase food-loads and decrease meal frequency when they forage in areas that are distant from the breeding colony. In 2001–2002, we studied the seasonal changes in at-sea distribution, food-load mass, meal frequency, and fledging mass in rhinoceros auklets (Cerorhinca monocerata), which forage in coastal waters during the day and feed their chicks at night. In both years, greater numbers of auklets were observed flying in northern waters that are more distant from the colony in June (65 km) and July (65–66 km) than in May (38–47 km). In July of both years, many auklets flew northward across the transect set 65–120 km north of the colony at sunrise; the birds returned south again at sunset, indicating that they foraged in waters outside the study area. This seasonal northward movement of the foraging area may reflect the migration of their main prey item, the Japanese anchovy (Engraulis japonicus), which move with the Tsushima Warm Current flowing from the southern Sea of Japan. Food-load mass did not increase seasonally. In both years, the estimated daily meal frequency was lower in July than in May or June, partly because of the increased foraging distance in July. Late-hatched chicks also displayed lighter fledging masses than early chicks in both years. We suggest that late breeders are required to forage at great distances for longer periods, which may result in decreased meal frequency and lighter fledging mass of their chicks.     

Design and synthesis of KNT-127, a δ-opioid receptor agonist effective by systemic administration

We have reported previously the novel δ-opioid agonist, SN-28, which was more potent in in vitro assays than the prototype δ-agonists, TAN-67 and SNC-80. However, when administered by subcutaneous injection, this compound showed no analgesic effect at dosages greater than 30 mg/kg in the acetic acid writhing test. We speculated that SN-28 was not effective in the test because the presence of the charged ammonium groups prevented its penetration through the blood–brain barrier. On the basis of our proposal, we designed the novel δ-agonist, KNT-127, which was effective with systemic administration.     

Determination of hydration properties and thermal behavior of Paecilomyces variotii by differential scanning calorimetry

Due to the structure and the composition of Paecilomyces variotii, the mycelia of this fungus could have potential applications as ingredients in wettable foods. For this use, drying could be employed, justifying the study of thermal behavior of P. variotii. The objectives of this work were to perform a study of thermal behavior of P. variotii isolates, to evaluate the hydration properties of these mycelia and to analyze the effect of different technological parameters on the latter properties. Wet cultures exhibited a wide endothermic transition, with mean values of peak temperature of 61°C and denaturation enthalpy of 4 J/g dry matter. Initial (50°C) and final (80°C) temperatures of the endothermic transition were used to dry the mycelia. Freeze-drying was also assayed. For all dried mycelia, a decrease in denaturation enthalpy between 40 and 50% was observed for drying at 50°C and freeze-drying, and a drastic decrease of almost 100% for drying at 80°C. According to the hydration properties, wet mycelia exhibited water holding capacity (WHC) value of 45 g water/g dry matter. Significant differences among dried mycelia, resulting WHC values in order: 50°C > freeze-dried > 80°C (p < 0.05) were revealed for each P. variotii strain. Fungi obtained by drying at 50 C and by freeze-drying, showed a rapid water absorption (t _1/2 < 0.1 min). Ionic strength, pH and particle size of dried mycelia influenced the hydration properties.     

Fragilidad y dependencia en Albacete (estudio FRADEA): razonamiento, diseño y metodología

Objective

To obtain a cohort of subjects of equal to or greater than 70 years, representative of a Spanish urban population, to estimate the prevalence of frailty and follow it up over time to analyse associated factors.

Material and methods

A prospective, population-based cohort study. From a population of 18,137 elderly persons, a representative sample of 1172 was randomly stratified, of which 993 (84.7%) agreed to take part. The variables collected were; sociodemographic, comorbidity, functional (n = 825), cognitive, affective and quality of life. On the patients who agreed, body composition was determined by bioimpedance analysis (n = 557), basal metabolic rate by indirect calorimetry (n = 450) and a blood sample was obtained for biomarkers (n = 859). Frailty was defined by the presence of 3 or more Fried criteria: unintentional weight loss, low energy, exhaustion, slow walking, and low physical activity. The cohort will be followed up over time until the death of the subjects.

Results

Mean age 79.4 (SD 6.4) years, with 601 (60.5%) women. A total of 21.3% were institutionalised; 16.9% were frail, 48.5% pre-frail, 21.3% non-frail, and 12.8% did not have the 3 criteria to be able to determine their state, of which 9.5% had moderate-severe incapacity, which would increase the prevalence of frailty to 26.4%.

Conclusions

A FRADEA cohort has been constructed, representative of an urban population in Spain. The prevalence of frailty in the cohort was 16.9%.     

Bacterial community and decomposition rate in long term fed-batch composting using woodchip and Polyethylene terephthalate (PET) as bulking agents

Long term fed-batch composting experiments were conducted for 200 days using two types of bulking agents; woodchip and PET flake, with periodic compost withdrawal through a washing process. The bacterial communities of composting materials in the two different bulking agents were also investigated by 16S rRNA gene clone analysis. The decomposition rate in both composting reactors was 86.1% and 88.2% of the total organic load, respectively. The control experiment of dead-end operation without compost withdrawal by washing process could not be maintained for more than 102 days because of its low performance. The reactor with compost withdrawal, however, improved the decomposition rate in the composting process, and could be applied in the long run. There was a significant difference in the bacterial community between the FBC reactor with woodchip and another with PET flake as the bulking agent though the decomposition rates were similar. The reactor with woodchip as the bulking agent consisted of 95% Bacillales while the PET flake reactor contained 54% of total bacteria count. In addition, Lactobacillales was dominant at 38% in the PET flake reactor and the bacterial community in general significantly differed from the woodchip reactor. Furthermore, there was a difference in the species composition in the Bacillales and the bacterial community showed a significant difference at the species level between the two reactors. Although bacterial community differed, the decomposition rates between the two reactors were similar and PET flake showed greater viability than woodchip as a bulking agent due to its high abrasion resistance and non-biodegradability.     

Real time visualization of 13N-translocation in rice under different environmental conditions using positron emitting Ttacer imaging system

The ammonium ion is an indispensable nitrogen source for crops, especially paddy rice (Oryza sativa L. cv Nipponbare). Until now, it has been impossible to measure ammonium uptake and nitrogen movement in plants in real time. Using the new technologies of PETIS (positron emitting tracer imaging system) and PMPS (positron multi-probe system), we were able to visualize the real time translocation of nitrogen and water in rice plants. We used positron-emitting 13N-labeled ammonium (13NH4+) and 15O-water to monitor the movement. In plants cultured under normal conditions, 13NH4+ supplied to roots was taken up, and a 13N signal was detected at the discrimination center, the basal part of the shoots, within 2 minutes. This rapid translocation of (13)N was almost completely inhibited by a glutamine synthetase inhibitor, methionine sulfoximine. In general, nitrogen deficiency enhanced 13N translocation to the discrimination center. In the dark, 13N translocation to the discrimination center was suppressed to 40% of control levels, whereas 15O-water flow from the root to the discrimination center stopped completely in the dark. In abscisic acid-treated rice, 13N translocation to the discrimination center was doubled, whereas translocation to leaves decreased to 40% of control levels. Pretreatment with NO3- for 36 hours increased 13N translocation from the roots to the discrimination center to 5 times of control levels. These results suggest that ammonium assimilation (from the roots to the discrimination center) depends passively on water flow, but actively on NH4+-transporter(s) or glutamine synthetase(s).     

Opioid δ1 receptor antagonist 7-benzylidenenaltrexone as an effective resistance reverser for chloroquine-resistant Plasmodium chabaudi

We evaluated antimalarial and/or chloroquine-resistance reversing effects of five opioid receptor antagonists. Although none of the evaluated compounds showed antimalarial effects, some of them, especially the δ₁ receptor antagonist, 7-benzylidenenaltrexone (BNTX) exhibited potent chloroquine-resistance reversing effects in Plasmodium chabaudi.