杆菌肽合成分子机制及高产策略

杆菌肽是一种非核糖体肽类的广谱抗菌素,目前广泛应用于农业和医药。过去,杆菌肽的生产水平增长缓慢。近年来国内外对杆菌肽的生物合成及调控的分子机制研究取得较大突破,为其育种和生产工艺优化、提高产量和质量、满足市场需求奠定基础。综述了国内外相关文献,重点关注杆菌肽生物合成基因簇及调节分子机制,兼顾其产量提高策略的报道,为今后开展相关育种研究、发酵工艺优化和提高杆菌肽的产量提供依据。     

温度对红曲菌以荞麦为基质固态发酵产色素的影响

发酵温度是影响微生物繁殖和代谢最重要的因素之一。利用红曲菌以荞麦为基质进行固态发酵,考查发酵温度对发酵产红曲荞麦中的生物量、色价和总黄酮含量的影响。结果表明,在发酵的前6 d,生物量随着发酵温度的升高而增大;6 d之后,30℃条件下生长量增长最快;发酵4 d后产生色素,黄、橙、红3种色素的色价在30℃条件下都增长最快。荞麦基质中的黄酮含量在发酵过程中变化不显著。     

两种不同耐热性菜豆品种在高温胁迫下叶绿素a荧光参数的差异

以两个耐热性不同的菜豆品种85-CT（耐热）和BBL-47（热敏感）为试材,研究其在不同高温胁迫强度下叶绿素a荧光参数的差异,结果表明：两个品种的叶绿素荧光Fv/Fm及Fv/Fo、电子传递速率（ETR）、均随高温胁迫时间延长呈下降趋势,但耐热品种85-CT下降幅度较热敏感品种BBL-47平缓,BBL-47随高温胁迫时间延长,其叶绿素a荧光诱导动力学曲线中的第二峰（M峰）消失。     

水分胁迫对苹果属植物叶片超微结构的影响

水分胁迫使苹果属植物Chl、Car含量下降,叶肉细胞叶绿体遭到破坏,抗旱性较弱的平邑甜茶受损的程度明显大于抗旱性较强的新疆野苹果。     

外源物质处理对高温胁迫下苹果果实抗氧化能力的影响

高温胁迫下,果实表皮组织抗氧化代谢变化的总趋势是O2-和MDA含量升高,当胁迫在一定范围内,SOD和POD活性上升;超过一定限度,SOD和POD活性下降。外源自由基产生剂能够增加内源O2-的含量,同时极显著提高SOD的活性。试验结果表明,在45℃温度胁迫下,果实表皮组织O2-含量增加14.52％~61.70％;SOD活性提高1.07~1.66倍。不同种类外源活性氧产生剂对内源O2-含量的影响效能有所不同。碱性二亚硫酸钠可直接产生O2-,所以诱导内源O2-合成的效果更大一些。不同种类外源物质均可显著或极显著提高果实表皮组织SOD和POD活性,提高果实的抗热性。     

CCD radiation temperature measurement method for hot continuous casting billet surface

According to the present research status and existing problems of hot continuous billet surface temperature non contact measurement technology, a real time temperature measurement model, which combines two-color(R,G) and monochrome (B) of surface radiation image, is established. The surface image is collected through tricolor charge coupled device (CCD) sensor, at the same time, the temperature dynamic response range of CCD can be improved by controlling integrated time and setting different apertures. Through computer image process technology, multi-point temperature can be measured simultaneously, and 2-D temperature field distribution on continuous casting billet surface can be realized. It is be proved by theory and application that the model and method can provide a theory and technology support for realizing surface temperature field on-line measurement for continuous casting billet.     

Effect of cooling rate on high temperature mechanical properties of weathering steel

High temperature mechanical properties are key factors which affect fracture production during deforming process of continuous casting. High temperature properties of weathering steel Q450NQR1 are tested in 3 cooling rates (1.65, 5, 10 ℃/s) using Gleeble thermo-mechanical simulator. Specimens appear austenite dynamic recrystallization at 1 050 ℃, and the ductility reaches the lowest point and the reduction of area approaches 23% at 850 ℃ in 3 cooling rates. As the cooling rate increases, the low ductility area where cracks are easy to be produced in slabs is enlarged and extended towards low temperature, and the ductility troughs are deepened. The increase of the cooling rate decreases the tensile stress and yield stress, while when the cooling rate increases to some degree, it doesn’t affect the stress. The low cooling rate decreases the film or network ferrite producing in austenite grain boundary, and the carbonitride of microalloy is enwrapped in matrix, which is helpful to improve the ductility of steel.     

Development of HRB500E seismic grade rebars by using VN microalloyed and controlled cooling process

In order to reduce the production cost of HRB500E seismic grade rebars, promote its production and application, HRB500E seismic grade rebars are developed by using VN microalloyed and controlled cooling process in domestic steel plant. The mechanism and effect of precipitation strengthening and fine-grain strengthening, the relationship between termination temperature after controlled cooling and mechanical properties of rebars, microstructure, welding and aging properties, high-strain and low-cycle fatigue properties for rebars are researched by using metallographic microscopy, scaning electron microcopy, transmission electron microscopy, X-ray diffraction apparatus, flash-butt welding, materials testing machine and mechanical properties testing. The results show that V(C,N) precipitation amount accounts for 66.67% of the total amount of vanadium by adding VN alloy in liquid steel, effect of microalloy precipitation strengthening is remarkable; when termination temperature after controlled cooling is controlled at 680～710 ℃, the amount of strength surplus for rebars is more than 25 MPa, R m/ R eL ratio is greater than 1.26, uniform elongation ( A gt) is more than or equal to 11.5%, good effect of fine grain strengthening and seismic performance are obtained; rebars have some good features such as low strain aging, good welding performance, high-strain and low-cycle fatigue properties; compared with VN microalloyed and hot-rolled process,the production cost is reduced by RMB 82 Yuan/t, and economic benefit is obvious.     

Effects of Night Temperature,Spikelet Position and Salicylic Acid on Yield and Yield‐Related Parameters of Rice (Oryza sativa L.) Plants

Periodic episodes of heat stress and seasonally high night temperatures (HNT) are predicted to occur more frequently in the current changing weather environment. These events affect aspects of crop growth and development, including oxidative‐stress damage, reducing crop yield and quality. Salicylic acid (SA), a naturally occurring phenolic compound, associated with thermo‐tolerance, prevents oxidative damage by detoxifying superoxide radicals and altering antioxidant capacity in plants. A study was conducted to determine the effects of HNT and SA on multiple rice yield‐determining parameters with special emphasis on effects of HNT and SA at different spikelet positions in the panicle. Plants were grown under ambient night temperature (27 °C) or HNT (32 °C) in the greenhouse. They were subjected to HNT through use of continuously controlled infrared heaters, starting from 2000 h to 0600 h. The HNT did not affect productive tillers, main‐stem panicle length or number of primary branches per panicle; however, reduced yield resulted from significant negative effects on spikelet fertility (SF), grain length and width. The grains located at the base of the panicle showed decreased fertility, length and width. Application of SA increased antioxidant capacity, thereby preventing damage to membranes, hence increasing yield by predominantly affecting SF in rice plants.     

大花蕙兰花芽分化与激素关系的研究

为了给大花蕙兰花期调控提供理论依据,在大花蕙兰花芽分化前用不同浓度的GA3、IBA、NAA和PP333均匀喷洒大花蕙兰的叶片和假鳞茎,研究各处理对大花蕙兰花芽分化的影响,同时研究了在大花蕙兰花芽分化过程中假鳞茎内源激素含量的变化,结果表明：（1）对大花蕙兰的成品苗喷洒外源激素会影响其始花期,其中GA3和PP333促进大花蕙兰的花芽分化,使其提早开花,根据使用浓度的不同,提早开花的时间为2~12天;而不同浓度的NAA处理则抑制了大花蕙兰的花芽分化,使开花推迟了4~11天。（2）IBA处理能够明显的促进花箭的生长,PP333处理则抑制了花箭的生长;各处理对大花蕙兰的花期和单枝花朵数影响不明显。（3）在大花蕙兰花芽分化的过程中,假鳞茎中ZT和GA3含量都是先上升后下降;ABA则是缓慢的上升;IAA则表现为下降。ZT/IAA和ABA/IAA的上升有利于大花蕙兰花芽的分化。