The effect of bulk density, water content and soil type on the diffusion of chloride in soil

The relative importance of soil bulk density, water content and potential on the self-diffusion and impedance factors of ³⁶C1 in a sandy loam and loamy clay were studied. The soil bulk densities used represented a range of conditions from freshly tilled seedbeds to compacted soils. The volumetric water contents and pF were the main factors controlling the soil impedance factors, with bulk density making a small but significant contribution.
Soil type affects the impedance factors through differences in anion exclusion volumes, the water contents of poorly connected pores that contribute little to the diffusion process, and tortuosity of the diffusion pathways.     

Teton Russet: An Early-Maturing,Dual-Purpose Potato Cultivar Having Higher Protein and Vitamin C Content,Low Asparagine,and Resistances to Common Scab and Fusarium Dry Rot

Teton Russet is an early-maturing, medium-russeted, potato cultivar with high merit for both fresh-pack and processing. In early harvest trials in the Pacific Northwest, Teton Russet had total yields similar to Russet Norkotah, and higher than Ranger Russet and Russet Burbank. Marketable yield of Teton Russet in the early harvest trials was also comparable to or higher than Russet Norkotah in Washington and Oregon, and higher than Ranger Russet and Russet Burbank at these sites, as well as in Idaho. In full-season trials, while total yield of the earlier-maturing Teton Russet tended to be lower than Ranger Russet and Russet Burbank, marketable yield was generally higher than Russet Burbank across the majority of sites due to its higher percentage of U.S. No. 1 tubers. Teton Russet is suitable for processing, with acceptable fry color following up to 8 months of storage at 8.9 °C. Uniformity of fry color was also very consistent. Teton Russet has shown lower levels of the amino acid asparagine relative to Ranger Russet and Russet Burbank which may contribute to lower acrylamide levels in French fries and other processed potato products. Teton Russet is notable for having resistance to common scab (Streptomyces spp.) and Fusarium dry rot, and is moderately resistant to tuber net necrosis. Analyses have also shown Teton Russet to have significantly higher protein levels than Russet Norkotah, Ranger Russet, and Russet Burbank, as well as higher vitamin C content than Russet Norkotah and Russet Burbank. Teton Russet was released in 2011 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington, and is a product of the Pacific Northwest Potato Variety (Tri-State) Development Program.     

Plant growth response from aged potato seed-tubers as affected by meristem selection and NAA

Plant growth from Russet Burbank seed-tubers of different ages was compared as affected by source of meristematic tissue (apical or basal) and NAA treatment. In controlled environment studies, single-eye seedcores from 17-mo-old seed-tubers produced twice as many shoots compared to those from 5-and 29-mo-old seed-tubers. Seed-tuber age and shoot dry weight/core were inversely related. Dry weight/shoot decreased as age increased to 17 mo and then remained unchanged from 17 to 29 mo. Apical meristems lost growth potential faster than basal meristems as age advanced. Meristem physiological age apparently depends on relative position of the buds as well as on the chronological age of the seed-tuber. NAA (10–40 mg/l) decreased the number of shoots/core, had no effect on shoot dry weight/core but increased the dry weight/shoot when applied to seedcores from 20-mo-old seed-tubers. On seedcores from 8-mo-old seed-tubers. NAA decreased the shoot dry weight (g/core, g/shoot). In field studies, NAA (100 mg/l) increased the total tuber yield of plants grown from seedpieces cut from 8-and 20-mo-old seed-tubers. These increases were manifested in age-specific effects on tuber grade. The effects of seedtuber age on plant growth and tuber yield were partially overcome by seedpiece treatment with NAA.     

大蒜素对植烟土壤酶活性的影响

采用室内模拟方法,研究了不同浓度大蒜素对植烟土壤中蔗糖酶、脲酶和过氧化氢酶活性的影响.结果表明,大蒜素对土壤中蔗糖酶的影响较大,呈现出"抑制-激活"的现象;大蒜素对土壤中脲酶的影响总体表现为激活时间明显长于抑制时间,表现为"激活-抑制-再激活"的过程.大蒜素对过氧化氢酶的影响不太明显,且各浓度的大蒜素对过氧化氢酶的影响基本相同,影响趋势表现为"激活-抑制".     

Setaria digitata was the main cause of equine neurological ataxia in Korea: 50 cases (2015–2016)

This study was performed to examine and clarify the cause of hindlimb ataxia and neuropathy seen in the South Korean horse population. Fifty horses diagnosed with hindlimb ataxia and neuropathy were referred for this study. Neurological examination was performed on 47 horses while necropsy was performed in all 50 animals. The occurrence of neurological diseases increased rapidly in the summer and 47 out of 50 horses were referred after the end of July. The incidence of neurological diseases started from the southern part of Korea in July and proceeded northward in August and September. Although there was no correlation with age, Thoroughbred and Warmblood horses showed a higher incidence rate than Halla and Jeju horses. The incidence rate was 5 times higher in geldings than in mares and stallions. Of the 20 cases, 16 were diagnosed with eosinophilic meningoencephalomyelitis in 2015. The most common lesions observed in 2016 were parasitic meningoencephalomyelitis (10 cases, 33%) and eosinophilic meningomyelitis (7 cases, 23%). Histopathological analysis of the brain and spinal cord revealed nematodes of approximately 100–200 µm in diameter, microcavitation and infiltrates of eosinophils, and brown pigmented macrophage infiltrates. The nematodes were identified as Setaria digitata via DNA sequencing, performed subsequent to polymerase chain reaction using DNA isolated from formalin-fixed paraffin-embedded tissue sections of the spinal cord. These results show that aberrant migration of Setaria digitata larva in the brain and spinal cord was a major cause for neurological signs in horses.     

Transfection of non-susceptible cells with Ovis aries recombinant lymphocyte function-associated antigen 1 renders susceptibility to Mannheimia haemolytica leukotoxin

Mannheimia haemolytica is an important etiological agent of pneumonia in domestic sheep (DS, Ovis aries). Leukotoxin (Lkt) produced by this organism is the principal virulence factor responsible for the acute inflammation and lung injury characteristic of M. haemolytica caused disease. Previously, we have shown that the leukocyte-specific integrins, beta(2) integrins, serve as the receptor for Lkt. Although it is certain that CD18, the beta subunit of beta(2) integrins, mediates Lkt-induced cytolysis of leukocytes, it is not clear whether CD18 of all three beta(2) integrins, LFA-1, Mac-1 and CR4, mediates Lkt-induced cytolysis of DS leukocytes. Since polymorphonuclear leukocytes, which express all three beta(2) integrins, are the leukocyte subset that is most susceptible to Lkt, we hypothesized that all three beta(2) integrins serve as the receptor for Lkt. The objective of this study was to determine whether DS LFA-1 serves as a receptor for M. haemolytica Lkt. We cloned the cDNA for DS CD11a, the alpha subunit of LFA-1, and co-transfected it along with the previously cloned cDNA for DS CD18, into a Lkt-non-suceptible cell line. Transfectants stably expressing DS LFA-1 were bound by Lkt. More importantly, Lkt lysed the DS LFA-1 transfectants in a concentration-dependent manner. Pre-incubation of Lkt with a Lkt-neutralizing monoclonal antibody (MAb), or pre-incubation of transfectants with MAbs specific for DS CD11a or CD18, inhibited Lkt-induced cytolysis of the transfectants. Exposure of LFA-1 transfectants to low concentrations of Lkt resulted in elevation of intracellular [Ca(2+)](i). Taken together, these results indicate that DS LFA-1 serves as a receptor for M. haemolytica Lkt.     

Acetylene inhibition of nitrous oxide reduction and measurement of denitrification and nitrogen fixation in soil

Reduction of N₂O in moist soil was inhibited completely by 10^?2 atm C₂H₂ and partially by 10^?5 atm C₂H₂. The effect of C₂H₄ was 10⁴ times less than that of C₂H₂. Denitrification of NO^?₃ occurred in anaerobically or aerobically incubated waterlogged soil and in anaerobic but not in aerobic moist soil. In the absence of C₂H₂ there was transient accumulation of N₂O. In the presence of C₂H₂ there was stoichiometric conversion of NO^?₃ to N₂O. Some kinetics of the reduction of N₂O and of NO^?₃ to N₂O are presented. Denitrification of 1 μg added NO^?₃-N.g^? could be measured within 1 h. Stoichiometries of production of N₂O from NO^?₂ and NO^?₃, respectively, and production of CO₂ attributable to denitrification were consistent with reported energy yields. Reduction of C₂H₂ to C₂H₄ occurred immediately following complete denitrification of added NO^?₃. The incubation of soil in the presence and in the absence of C₂H₂ thus permits assay of both denitrification and N₂ fixation and provides information on the mole fraction of N₂O in the products of denitrification.