Response of denitrifying communities to successive soil freeze–thaw cycles

The effect of soil freeze–thaw cycles on the denitrification potential was examined based on the C₂H₂ inhibition method. The gross N₂O production curve of the soil sample (incubation with C₂H₂) showed minor changes between the freeze–thaw treatment and the unfrozen control. However, kinetics analysis revealed that the initial production rate, an indicator of the population density of denitrifying communities, decreased (P = 0.043) and the specific growth rate constant, an indicator of the activity of denitrifying communities, increased (P = 0.039) as a result of the freeze–thaw cycles in five of six soil samples examined. The increase in the specific growth rate constant suggested the stimulation of the activity of denitrifying communities that survived after the freeze–thaw cycles and may explain the minor suppression on the gross N₂O production in spite of decreasing the population density of denitrifying communities that was suggested by the initial production rate. The net N₂O production curve of the soil sample (incubation without C₂H₂) showed a remarkable change in one out of six soil samples, and in that one soil sample, N₂O release to the atmosphere was largely stimulated (7.6 times) by the freeze–thaw cycles. However, the stimulation of the N₂O release by the freeze–thaw cycles was even observed in two other selected soil samples (4.6 and 1.8 times), suggesting that an imbalance in the N₂O-producing and N₂O-reducing activities of denitrifying communities might complementally explain the N₂O release stimulated by the freeze–thaw cycles.     

Flow cytometric analysis of chicken NK activity and its use on the effect of restraint stress

Immune system is organized by the influence of both neural and endocrine systems. NK activity plays an important role in the innate immunity. In this study, we observed the effects of restraint stress on chicken peripheral blood NK activity. Viability of FITC-labeled RP9 was measured with PI after treatment with the effector cells. Chicken peripheral blood CD8alpha+ cells expressed strong cytotoxic activity, in contrast to thrombocytes, while peripheral blood CD3+ CD8alpha+ cells and CD4+ cells had little cytotoxic activity. Con A supernatant enhanced the cytotoxic activity of CD8alpha+ cells. Therefore, it is considered that these cytotoxic activities measured by flow cytometry (FCM) analysis are NK activity. When chickens were exposed to restraint stress, the levels of serum corticosterone increased transiently over a short period of time while the NK activity decreased. The decreased NK activity, however, did not recover to the intact levels for a long time, even once the serum corticosterone levels had recovered. These data indicate that chicken NK activity is able to be measured by flow cytometric analysis and that restraint stress causes severe damage to the chicken NK activity.     

猪隐秘杆菌型出血性坏死性脾炎

六月龄去势公猪表现昏睡、食欲不振、站立困难。尸检发现脾脏边缘呈多重出血灶。从脾脏、肾脏、肌肉和肝脏中分离出革兰氏阳性杆菌,对分离株(TO16177)的16S rDNA基因序列比较分析发现,其可能与未发表过的隐秘杆菌属HJ57-14E菌株(登记号:gi18873551)(比较675bp个碱基,相似性达99.7%)为同一个属。脾脏组织切片的组织学检查发现呈广泛性坏死和炎症,其中革兰氏阳性杆菌显而易见。肝脏中可见多病灶的坏死斑。免疫组织化学检测发现,分离株与抗化脓性隐秘杆菌属(Arcanobacterium pyogenes)和内氏放线菌(Actinomyces naeslundii)的多克隆抗体具有交叉反应,且与后者的交叉反应更强烈。相似的反应也见于扁桃体的化脓灶中分离株,偶尔也见于脾脏和淋巴结中的分离株。本研究结果表明,这种未公开发布的隐秘杆菌属的细菌会引起生长肥育猪多器官功能衰竭,而后继发急性出血性坏死性脾炎。     

Na?ve-like conversion enhances the difference in innate in vitro differentiation capacity between rabbit ES cells and iPS cells

Quality evaluation of pluripotent stem cells using appropriate animal models needs to be improved for human regenerative medicine. Previously, we demonstrated that although the in vitro neural differentiating capacity of rabbit induced pluripotent stem cells (iPSCs) can be mitigated by improving their baseline level of pluripotency, i.e., by converting them into the so-called “naïve-like” state, the effect after such conversion of rabbit embryonic stem cells (ESCs) remains to be elucidated. Here we found that naïve-like conversion enhanced the differences in innate in vitro differentiation capacity between ESCs and iPSCs. Naïve-like rabbit ESCs exhibited several features indicating pluripotency, including the capacity for teratoma formation. They differentiated into mature oligodendrocytes much more effectively (3.3–7.2 times) than naïve-like iPSCs. This suggests an inherent variation in differentiation potential in vitro among PSC lines. When naïve-like ESCs were injected into preimplantation rabbit embryos, although they contributed efficiently to forming the inner cell mass of blastocysts, no chimeric pups were obtained. Thus, in vitro neural differentiation following naïve-like conversion is a promising option for determining the quality of PSCs without the need to demonstrate chimeric contribution. These results provide an opportunity to evaluate which pluripotent stem cells or treatments are best suited for therapeutic use.     

Effects of five oleanolic acid triterpenoid saponins from the rhizome of Anemone raddeana on stimulus-induced superoxide generation, phosphorylation of proteins and translocation of cytosolic compounds to cell membrane in human neutrophils

Five oleanolic acid triterpenoid saponins (OTS-1, 2, 3, 4 and 5) were isolated from the rhizome of Anemone raddeana. The effect of these triterpenoid saponins on stimulus-induced superoxide generation in human neutrophils was assayed by measuring the reduction of ferricytochrome c using a dual-beam spectrophotometer. The phosphorylation of neutrophil proteins, and translocation of p67(phox), p47(phox) and Rac to plasma membrane were investigated using specific monoclonal antibodies. The five oleanolic acid triterpenoid saponins used in this experiment suppressed N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced superoxide generation in a concentration-dependent manner. OTS-1, 2 and 4 suppressed phorbol 12-myristate 13-acetate (PMA)- and arachidonic acid (AA)-induced superoxide generation in a concentration-dependent manner, but OTS-3 and 5 showed no effect. fMLP- and PMA-induced tyrosyl or serine/threonine phosphorylation, and fMLP-, PMA- and AA-induced translocation of p67(phox), p47(phox) and Rac to plasma membrane were in parallel with the suppression of the stimulus-induced superoxide generation.     

Reductions in greenhouse gas emissions by using wood to protect against soil liquefaction

We compared the greenhouse gas (GHG) emissions from a log pile (LP) to those from a sand compaction pile (SCP) and from cement deep mixing (CDM) as measures against soil liquefaction, assuming that forest and waste management scenarios influence the GHG (CO₂, CH₄, and N₂O) balance of wood. We found little difference between the LP and SCP methods with respect to GHG emissions from fossil fuel and limestone consumption. However, GHG emissions from the CDM method were seven times higher than emissions from the LP method. In the GHG balance of wood, when the percentage of CH₄ emissions from carbon in underground wood was lower than 3.3%, permanent storage in the log achieved greater reductions in GHG emissions than using the waste log as fuel in place of coal or heavy oil. In order to obtain reductions in GHG emissions by replacing SCPs or CDM with LPs, sustainable forest management with reforestation and prevention of CH₄ emissions from the underground log are essential. Using reforestation, permanent storage of the log, no CH₄ emission from the log, and using logging residues instead of coal, the LP can achieve reductions in GHG emissions of 121 tonnes of CO₂ per 100 m² of improvement area by replacing CDM.     

Characterization of myofibrillar adenosine triphosphatase activity and liberation of actin from myofibrils upon heating chicken breast meat

Denaturation of actin and myosin in myofibrils induced by heating at 50°C was investigated to reveal the mechanism of irreversible liberation of actin from myofibrils on heating at lower temperatures than conventional cooking. Denaturation of these proteins was determined by Mg²⁺‐ATPase (adenosine triphosphatase) and Ca²⁺‐ATPase activities. When minced meat was heated for 20 min, actin was liberated accompanying denaturation of 80% of actin and 50% of myosin. Heating of the myofibrillar fraction (MFF) isolated from meat homogenate induced much slower denaturation of actin than myosin. When MFF was heated with sarcoplasmic fractions, denaturation of actin was facilitated, suggesting that sarcoplasmic fractions contain factors to facilitate actin denaturation. Inosine‐5′‐monophosphate, a component of sarcoplasmic fractions, was shown to have no effect on actin and myosin denaturation. These results suggest that heating meat at 50°C dissociates binding (‘Bond A’) between actin and myosin participating in ATPase activities, resulting in denaturation of both proteins under influence of sarcoplasmic components. Although denaturation of actin and myosin disrupted Bond A, actin was not liberated simultaneously, suggesting the presence of another bond (‘Bond B’, more heat‐stable than Bond A) between both proteins and necessity of disruption of Bond B for actin release from myofibrils.     

Genetic diversity of the entomopathogen<Emphasis Type="Italic">Verticillium lecanii</Emphasis> on the basis of vegetative compatibility

Forty-three isolates ofVerticillium lecanii from insects, phytopathogenic fungi and other substrates were tested for vegetative compatibility by observing heterokaryon formation among complementary nitrate-nonutilizing (nit) mutants.nit mutants were isolated from 42/43 strains examined. Twenty-one isolates were self-incompatible, and the remaining 21 isolates were divided into 14 vegetative compatibility groups (VCGs): ten containing only a single strain each, and the remaining four containing two to four isolates each. Members of isolates in each of these VCGs all shared the same IGS haplotype. Further, the isolates within a VCG were correlated with one another in part by fragment patterns of mt-LrDNA, -SrDNA, Bt-2 and H4 region, by PCR-RFLP and -SSCP, but not by dsRNA. Two isolates belonging to VL-J2 have high virulence to aphids, whereas strains from VL-J1 lack this character. These findings indicate that two VCGs (VL-J1 and -J2) may originate from two distinct clonal lineages. Alternatively, high VCG diversity and HSI frequency ofV. lecanii might be associated with an array of distinct lineages. These data not only suggest relationships among DNA polymorphisms, virulence, and VCG, but also demonstrate genetic heterogeneity ofV. lecanii. http://www.phytoparasitica.org posting Sept. 30, 2003.     

Imaging of single organic molecules in motion

High-resolution transmission electron microscopy revealed nearly atomically precise images of stepping conformational change and translational motion of single hydrocarbon molecules confined in carbon nanotubes. One or two C12 or C22 alkyl chains were tethered to a carborane end group and then embedded in the nanotubes. Images of the hydrocarbon chains interacting with each other and with a graphitic surface provide information on three-dimensional structures and dynamic molecular interactions that cannot be obtained by other analytical methods.