Seasonal variation of paulownia witches’-broom phytoplasma in paulownia trees and distribution of the disease in the Tohoku district of Japan

Seasonal variation of paulownia witches’-broom (PWB) phytoplasma within different organs (leaves, branch and trunk bark and roots) in paulownia trees was investigated by the amplification of a PWB-specific DNA fragment by the polymerase chain reaction (PCR). In leaf samples, PWB phytoplasma was first detected in June and the incidence gradually increased. On the other hand, the PWB was detected at relatively low incidence in branch bark, trunk bark and roots and the incidence did not change among seasons. A survey of PWB in 27 fields in the Tohoku district of Japan showed that malformed flower buds were observed in paulownia trees in almost all of the fields. PWB-phytoplasma was also detected by PCR from paulownia trees in almost all of the fields in Iwate and Fukushima Prefectures. The frequencies of trees in which phytoplasma was detected by PCR were higher than those in which symptoms were observed. These results indicated that PCR amplification of a PWB-specific DNA fragment is an effective tool for practical diagnose and that PWB is widely distributed in the Tohoku district of Japan.     

Decreases in serum apolipoprotein B-100 and A-I concentrations in cows with milk fever and downer cows

Milk fever occurring during the peripartum period has been suggested to be caused by fatty liver developed during the nonlactating stage because diseased cows have increased serum concentrations of non-esterified fatty acids (NEFA) and show hepatic lipidosis. In cows with fatty liver and related diseases such as ketosis, serum concentrations of apolipoprotein (apo) B-100 and apoA-I are decreased. The purpose of the present study was to examine whether apoB-100 and apoA-I concentrations are similarly decreased in cows with milk fever. Apolipoprotein concentrations were also measured in cows with downer syndrome, which has been suggested to be related, at least in part, to milk fever. Compared with healthy cows during early lactation, apoB-100 and apoA-I concentrations were decreased in cows with milk fever and also in downer cows. In cows with milk fever, the decreases in apoB-100 and apoA-I concentrations were associated with increased NEFA and decreased cholesterol and phospholipid concentrations. However, in downer cows, serum lipid concentration changes were not as distinct as in cows with milk fever. These results, coupled with previous findings on the decreases in apoB-100 and apoA-I concentrations of cows with fatty liver-related diseases, suggest that fatty liver is involved in the development of milk fever and partly in that of downer cow syndrome.     

Oxidative metabolism of lindane and its isomers with microsomes from rat liver and house fly abdomen

Lindane and other hexachlorocyclohexane isomers produced 2,4,6-trichlorophenol as the major oxidative metabolite when incubated in the presence of NADPH under aerobic condition. A mechanism for the formation of 2,4,6-trichlorophenol is proposed, which includes direct oxygenation of the cyclohexane ring. The proposed mechanism is supported by data from studies of model chemical reactions of the pentachlorocyclohexanol isomers. Pathways leading to 1,2,4-trichlorobenzene, tetrachlorobenzene isomers, 2,4,5-trichlorophenol, and tetrachlorophenol isomers are discussed, and are considered to include the route through pentachlorocyclohexene and hexachlorocyclohexene. Reductive dechlorination of lindane under anaerobic condition was observed using microsomes and NADPH.     

Action-potential modulation during axonal conduction

Once initiated near the soma, an action potential (AP) is thought to propagate autoregeneratively and distribute uniformly over axonal arbors. We challenge this classic view by showing that APs are subject to waveform modulation while they travel down axons. Using fluorescent patch-clamp pipettes, we recorded APs from axon branches of hippocampal CA3 pyramidal neurons ex vivo. The waveforms of axonal APs increased in width in response to the local application of glutamate and an adenosine A(1) receptor antagonist to the axon shafts, but not to other unrelated axon branches. Uncaging of calcium in periaxonal astrocytes caused AP broadening through ionotropic glutamate receptor activation. The broadened APs triggered larger calcium elevations in presynaptic boutons and facilitated synaptic transmission to postsynaptic neurons. This local AP modification may enable axonal computation through the geometry of axon wiring.     

Serum clearance of iodixanol for estimating glomerular filtration rate in calves

To evaluate serum clearance of iodixanol, applicable to the estimation of glomerular filtration rate (GFR), clinically healthy and experimentally-induced nephropathy calves were prepared. Iodixanol was administered intravenously at 40 mg I/kg, and blood was withdrawn 60, 120, and 180 min later. Serum iodixanol concentration was determined by high-performance liquid chromatography. No statistical difference in GFR was noted between strains (Holstein vs. Japanese Black) or sexes, and the α(2)-adrenergic agonist xylazine increased GFR. In calves subjected to right renal vessel ligation, followed by a left nephrectomy, a marked reduction in GFR was observed with renal ischemic changes. These results suggest that the GFR estimation by serum iodixanol clearance is a ready-to-use tool in calf research and practice owing to the ease of monitoring serial renal function.     

Detection of QTLs for white-back and basal-white grains caused by high temperature during ripening period in japonica rice

There is increasing evidence that global warming affects the development of rice. High temperatures during ripening increase the ratio of undesirable chalky grains followed by deteriorating grain appearance quality. In order to detect quantitative trait loci (QTLs) controlling the occurrence of white-back and basal-white chalky grains of brown rice, QTL analysis was performed using recombinant inbred lines derived from a cross between two strains, ‘Tsukushiroman’ (sensitive to heat stress) and ‘Chikushi 52’ (tolerant of heat stress). The F₇ and F₈ lines were exposed to heat stress during the ripening period in two locations, Fukuoka and Kagoshima, in Japan. QTLs for white-back grains and basal-white grains were detected on chromosomes 1, 3, and 8, and those for basal-white grains were detected on chromosomes 2, 3, and 12. QTLs on chromosome 8 for white-back grains were shared in the plants grown in both locations. Near-isogenic lines (NILs), which harbored a segment from ‘Chikushi 52’ on chromosome 8 with the genetic background of ‘Tsukushiroman’, showed relatively lower ratios of white-back grains than ‘Tsukushiroman’. Therefore, insertion of the ‘Chikushi 52’ genomic region of the QTL on chromosome 8 can improve the quality of rice when it is grown under heat stress conditions.     

Changes in the plasma levels of several bone markers in newborn calves during the first two days of life

The fluctuations in the plasma levels of several bone markers were investigated in newborn calves. Experiment1 monitored the postnatal changes in the plasma levels of tartrate-resistant acid phosphatase isoform 5b(TRAP5b), total alkaline phosphatase (t-ALP) and bone-specific alkaline phosphatase (BAP) in four calves.These markers increased significantly from 9−20 hr after the first colostrum-suckling compared with the valuesimmediately after birth. Experiment 2 evaluated changes in the plasma TRAP5b, t-ALP, BAP and type I collagencross-linked N-telopeptide (NTx) levels within 2 days post-birth in five calves with successful passiveimmunization via colostrum (non-deficient group) and five others with poor colostrum intake (deficient group).The non-deficient group had significantly higher plasma levels of the four parameters around 12 hr of lifecompared with the deficient group. The results suggest that the increase in plasma bone markers in calves inthe first day of life is related to the colostrum intake.     

Nitrate Decrease with Isotopic Fractionation In Riverside Sediment Column During Infiltration Experiment

This study determined isotopic fractionation of nitrate-nitrogen during denitrification in riparian aquifer sediments by sequential-column experiments at two different water flow rates. The purpose was to discuss the relationships of nitrogen isotopic enrichment factor of denitrification, denitrification rate, and infiltrating condition in sediment. Sandy sediment and groundwater were collected from floodplain in the middle reach of the Tama River where nitrogen isotopic enrichment factor for denitrification had been measured in a result of previous field observation. The denitrification rates and the isotopic enrichment factors of nitrate-nitrogen were estimated at 2.1 mgN dry-kg^?1 day^?1 and ?32.9‰ during the low water flow condition, and at 3.5 mgN dry-kg^?1 day^?1 and ?34.1‰ during the high water flow condition. The calculated water flow rates of the present column experiments were 300–400 times higher than that of the field observation. Because of the fast flow rate, nitrate was expected to continuously pass though active denitrifying sites in the small pore spaces of sediment, and nitrate supply to denitrifers by infiltration flow transport greatly exceeded the supply by diffusion. The observed denitrification rates was proportional to Peclet number as the ratio of solute nitrate transport to the diffusion, and apparent nitrogen isotopic enrichment factors during denitrification of our column experiments were lower than those obtained from the field observation. This study showed that denitrification rate and apparent nitrogen isotopic enrichment factor of denitrification in sediment depended on Peclet number.