结果初期黄冠梨对春施15N-尿素的吸收、分配与利用

以3年生黄冠梨为材料,探讨了早春施用¹⁵N尿素后,树体在萌芽期-新梢缓慢生长期和新梢缓慢生长期-果实成熟期对氮素的吸收、分配与利用特性。结果表明: 梨树在萌芽期-新梢缓慢生长期主要以新梢和叶片等营养器官生长为核心;在新梢缓慢生长期-果实成熟期则以根系等贮藏器官生长为主,果实产量品质形成为辅,且树体尤其是贮藏器官的生物量成倍增加。由于各器官尤其是新梢和叶片生长旺盛、新梢缓慢生长期吸收的标记氮量相对较多,各器官吸收的肥料氮(Ndff)值相对较高;果实成熟期除粗根外各器官的Ndff值均低于新梢缓慢生长期。萌芽期到新梢缓慢生长期吸收的标记氮主要分配在新梢和叶片营养器官中,新梢缓慢生长期到果实成熟期吸收的标记氮则主要分配在贮藏器官中;整个生育期间,植株吸收的标记氮在贮藏器官中分配率最高,营养器官次之,生殖器官中分配率最低。3年生梨树从萌芽期-新梢缓慢生长期、新梢缓慢生长期-果实成熟期吸收的肥料氮分别占当年总吸氮量的31.1%和21.0%,而两个时期内吸收的土壤氮占比分别达68.9%和79.0%。     

扰动环境中不同刈割方式柠条营养生长补偿的影响

 柠条（Caragana korshinskii）在地上组织破坏后进行补偿性生长,这是重复利用柠条资源的基础,但对 柠条不同刈割方式下营养生长补偿的模式有待探讨。该文通过5种刈割方式：去除主枝长的30%（30%RSL） 、去除主枝长的60%（60%RSL）、去除分枝数的25%（25%RSN）、去除分枝数的50%（50%RSN）和去除分枝 数的100%（100%RSN）来研究柠条的营养生长补偿。结果表明：刈割处理的柠条生物量当年发生了超补偿 ,当年生枝数/枝、当年生枝长、当年生枝生物量/枝、当年生枝生物量/株比对照高。对照、30%RSL和 60%RSL 处理未长出基梢。 100%RSN处理的基梢数/刈割枝、基梢长、单个基梢平均生物量显著高于25%RSN 和50%RSN处理,基梢生物量/株随刈割去除生物量的增加而增加。100%RSN 处理未结果,其它处理果实产量 表现出超补偿或精确补偿。对照处理营养生长和生殖生长均低,其它处理当年生枝生物量与果实产量成显 著负相关。从整个生长季节来看,营养生长主要集中在果实成熟之前。我们认为,100%RSN处理是柠条地上 组织破坏后尽快恢复的合理方式,其当年生生物量远高于其它处理。顶端优势的破坏促使休眠芽的萌发, 根冠比的改变使地上组织获得较多养分和水分,根系储存的碳水化合物的供应是促使刈割柠条营养生长超 补偿的的可能机制,而减少生殖生长对资源的消耗,是100%RSN处理地上生物量尽快恢复的另一重要因素 。     

扰动环境中不同刈割方式柠条营养生长补偿的影响

柠条（Caragana korshinskii）在地上组织破坏后进行补偿性生长,这是重复利用柠条资源的基础,但对 柠条不同刈割方式下营养生长补偿的模式有待探讨。该文通过5种刈割方式：去除主枝长的30%（30%RSL） 、去除主枝长的60%（60%RSL）、去除分枝数的25%（25%RSN）、去除分枝数的50%（50%RSN）和去除分枝 数的100%（100%RSN）来研究柠条的营养生长补偿。结果表明：刈割处理的柠条生物量当年发生了超补偿 ,当年生枝数/枝、当年生枝长、当年生枝生物量/枝、当年生枝生物量/株比对照高。对照、30%RSL和 60%RSL 处理未长出基梢。 100%RSN处理的基梢数/刈割枝、基梢长、单个基梢平均生物量显著高于25%RSN 和50%RSN处理,基梢生物量/株随刈割去除生物量的增加而增加。100%RSN 处理未结果,其它处理果实产量 表现出超补偿或精确补偿。对照处理营养生长和生殖生长均低,其它处理当年生枝生物量与果实产量成显 著负相关。从整个生长季节来看,营养生长主要集中在果实成熟之前。我们认为,100%RSN处理是柠条地上 组织破坏后尽快恢复的合理方式,其当年生生物量远高于其它处理。顶端优势的破坏促使休眠芽的萌发, 根冠比的改变使地上组织获得较多养分和水分,根系储存的碳水化合物的供应是促使刈割柠条营养生长超 补偿的的可能机制,而减少生殖生长对资源的消耗,是100%RSN处理地上生物量尽快恢复的另一重要因素 。     

春梢叶损失对刺梨生长和果实产量与品质的影响机理分析

2017年以3年生的‘贵农5号’刺梨(Rosa roxburghii Tratt.)为材料,于5月初开花期前采用人工摘叶的方法,对试验树当年春梢进行失叶率20%、40%、60%和80% 处理,以不摘叶的植株为对照(CK),研究失叶后3年中不同失叶率处理对刺梨新梢生长、叶片营养元素含量、果实产量及品质的影响机理,分析摘叶后30 d内的失叶春梢中内源激素含量,存留叶的净光合速率(P_n)和蒸腾速率(T_r),失叶当年刺梨果实中影响维生素C和黄酮合成积累的关键酶(GalLDH、MDHAR、DHAR、AAO、APX和PAL、C4H、4CL、CHS)的活性,探究失叶对刺梨生长和果实产量、品质及其相关生理特性的影响机理,为刺梨合理采叶量的确定和因灾失叶的损失评估提供理论依据。结果表明：(1)刺梨春梢失叶后会促进当年夏梢萌发,增加夏梢数量,抑制当年秋梢和翌年、第3年的新梢生长。(2)在摘叶后的30 d内,失叶春梢中IAA和ABA含量迅速降低,GA₁₊₃和ZR含量迅速增加,内源激素的变化对当年夏梢的萌发具有协同促进作用。(3)在摘叶后15 d内,春梢存留叶的P_n迅速增强,之后迅速减弱,失叶春梢存留叶在短期内具有明显的光合作用补偿反应,但难以长期持续。(4)春梢失叶率超过20%后,会导致刺梨植株的养分损失,尤其是叶中的N、P、K、Mg元素的损失极为严重,导致树势衰弱,新梢的正常生长受到抑制。(5)在刺梨果实维生素C和类黄酮物质合成积累的关键时期,果实中GalLDH、PAL、C4H、4CL、CHS的活性均随失叶率的增大而明显减弱,果实中的维生素C和类黄酮物质的含量也随之明显减少。研究发现,春梢失叶率过大会明显降低刺梨叶中的养分含量和果实的产量及品质,且这种不利影响可持续多年;在春季对果叶兼用的刺梨嫩叶进行采收利用时,采叶量应控制在20%内。     

不同种源长白落叶松(Larix olgensis)生长的比较研究

通过对柴河林业局头道林场一块8年生的落叶松人工林优势种群的当年生的生长节律与生物量的研究发现:优势林分的当年生枝及顶枝的生长较常规林分高峰期多、高峰期持续时间长和生长量大的优点和不同;生物量的分配的研究结果也说明优势林分的树干生物量积累的比重较常规林分高,证明了该罕见优势林分速生原因的内质性,是一个难得的优良种源。     

旱垂柳和垂柳黄化与土壤条件关系的研究

旱垂柳和垂柳既是优美的城市观赏绿化树种,又是用材林和防林的重要造林树种,这两个树种在哈尔滨市道里区苗辅和大庆等黑钙土上有程度卜同的黄化现象,轻者,树叶自开放时便开始变,为白,变薄,叶片小,重者,叶子提早从植株上脱落,枯梢,至整个植株枯死,一般情况是绝大多数植株全株叶子变黄,这种黄化症影响了大苗的正常生长和苗木质量,给苗辅生产经营带来了一定的损失,生产部门提出了解释和解决这一问题的迫切要求。根据生产     

不同果实生长期下亏缺灌溉对渭北苹果生长发育、品质及水分利用效率的影响

【目的】探索节水、控水方式调控苹果水分高效利用效率的机制,优化渭北苹果主产区节水、丰产和增收的管理方式。【方法】以陕西省咸阳市乾县铁佛镇果友协会试验站8年生‘烟富3号/T337’苹果树为试材,设置充分灌溉（灌溉后土壤相对含水量为75%）和轻度亏缺灌溉（灌溉后土壤相对含水量为50%）两个灌水量水平,组成果实生长期和膨大期均充分灌溉（CK）、果实生长期和膨大期均轻度亏缺灌溉（W1）、果实生长期轻度亏缺灌溉和膨大期充分灌溉（W2）及果实生长期充分灌溉和膨大期轻度亏缺灌溉（W3）4个亏缺灌溉模式处理。测定春梢生长指标,果实品质指标和果实产量指标,计算水分利用效率、灌溉水利用效率、果实综合评价满意度以明确最佳的亏缺灌溉方式。【结果】（1）苹果新梢长度及叶片叶绿素相对含量（SPAD）在各处理间无显著性差异,而其春梢直径在各处理下显著降低。（2）与CK相比,单果重在 W1处理下显著降低了10.3%,果实可滴定酸含量在W2处理下显著降低14.7%,果形指数和可溶性固形物含量在3种水分亏缺灌溉处理下均无显著变化。（3）W1处理能显著提高果皮黄色值b*,W2处理能显著提高果皮色泽饱和度C*,而各亏缺灌溉处理对果皮亮度值L*和红绿值a*均无显著影响。（4）与CK相比,果实产量在各亏缺灌溉处理下降低13.4%~24.7%,但仅W1处理降幅达显著水平;果树灌溉水利用效率在各亏缺灌溉处理均不同程度提高,但仅W1处理显著提高了38.0%;果树耗水量和水分利用效率在各亏缺灌溉处理下无显著性差异。（4）果实综合评价满意度表现为W2＞CK＞W3（W1）。【结论】陕西渭北地区苹果在生长期轻度亏缺灌溉和膨大期充分灌溉（W2）模式下果实的综合评价满意度最高,果实产量、单果重无显著变化,而果实品质较优,果树水分利用效率较高。     

不同节水灌溉方式对干旱山地板栗生长结实的影响

在山东省泰安市半干旱、半湿润气候区的山地果园,以板栗为试材,研究了陶罐贮水、蓄水穴和畦灌覆盖3种节水灌溉方式下栗园土壤水分特征及对板栗根系、树体生长和结实的影响.结果表明：与畦灌(对照)相比,3种节水灌溉方式均能延长果园土壤保湿时间,其中陶罐贮水处理效果最明显,保湿时间长达32 d,较对照延长13 d.节水处理下,板栗结果枝长度和数量、叶片面积和质量、果前梢混合芽数量等均较对照明显增加.陶罐贮水和蓄水穴处理能对深层土壤根系进行灌溉并诱导深层根系生长,降低了浅层干旱对根系的胁迫.3种节水灌溉均能大幅度提高板栗果实产量,陶罐贮水、蓄水穴和畦灌覆盖处理的产量分别较对照提高18.8%、16.5%和14.2%.     

赤霉素对日本落叶松幼苗顶芽生长的影响

日本落叶松(Larix japonicus)为华北和东北地区主要造林树种之一。但在次年春季幼苗移栽后,幼苗出现干尖现象,即顶芽和一些侧芽干枯,干尖长1～4厘米,严重的仅剩下基部几个侧芽,群众称之为“干梢”。顶芽死亡率达90％,直接影响苗木的生长和上山育林。为解决这一问题,我们在抚顺矿务局林场后腰分场苗圃从不同角度进行了一系列试验。本文是关于赤霉素试验(1969～1972)的初步结果。     

龙眼树干、枝、叶、果实空间分布格局研究

选择6年生早结丰产龙眼植株,采用分层调查法对名优品种储良龙眼树体结构特别是树冠上枝、叶、果实的分布格局及其相互关系进行了分析研究。结果表明,主干较矮、树冠为自然半圆头形,冠幅略大于冠厚,主枝4或5条,主枝与各级分枝在树冠空间上分布较均匀,枝梢、结果母枝和果实比较均匀地分布在平行于主干的纵向各行上,在垂直于主干方向上,则以中部各层所占比重较大,绿叶层较厚,且和果实均匀分布于树冠表层,果实主要集中在中部距冠底60－150cm的冠层上,占总产量的78．9％,各冠层中的枝梢、结果枝、果实粒数、果实产量之间存在显著线性相关关系。     

Characterization of three different flavodoxins from Azotobacter vinelandii

The flavodoxins from Azotobacter vinelandii cells grown N2-fixing and from cells grown on NH4OAc have been purified and characterized. The purified flavodoxins from these cells are a mixture of three different flavodoxins (Fld I, II, III) with different primary structures. The three proteins were separated by fast protein liquid chromatography; Fld I eluted at 0.38 M KCl, Fld II at 0.43 M KCl and Fld III at 0.45 M KCl. The most striking difference between the three flavodoxins was the midpoint potential (pH 7.0, 25 degrees C) of the semiquinone/hydroquinone couple, which was -320 mV for Fld I and -500 mV for the other two flavodoxins (Fld II and Fld III). All three flavodoxins were present in cells grown on NH4OAc. In cells grown on N2 as N source only Fld I and Fld II were found. The concentration of Fld II was 10-fold higher in N2-fixing cells than in cells grown on NH4OAc. Evidence has been obtained that Fld II is involved in electron transport to nitrogenase. As will be discussed, our observation that preparations of Azotobacter flavodoxin are heterogeneous, has consequences for the published data.     

洞庭湖区东方田鼠种群动态及其危害预警

洞庭湖区东方田鼠以湖滩沼泽为最适栖息地．秋末洞庭湖水位回落,湖滩出露,东方田鼠从农田迁回到湖滩生活、繁殖,种群数量呈逐月上升趋势．春末夏初,洞庭湖水位上涨,湖滩被淹,东方田鼠被迫越过大堤迁入垸内农田．其种群动态由“水位影响东方田鼠的栖息地变换”主导．每年迁入农田的数量首先取决于东方田鼠在湖滩生活繁殖时期的长短,亦即枯水期的天数;其次3月降雨量对东方田鼠在湖滩上的繁殖有较大的影响．东方田鼠迁入垸内后,种群数量呈逐月下降趋势．在分析影响洞庭湖区东方田鼠种群数量动态的主要因子的基础上,提出了东方田鼠种群迁入垸内农田的迁入量预警模型．经过几年的实际预测,吻合情况良好．     

洞庭湖区东方田鼠迁移的研究

洞庭湖区东方田鼠以湖滩上的芦苇＋荻或薹草沼泽为最适栖息地,枯水季节,多在其上生长、繁殖。汛期,随着湖水上涨,湖滩面积缩小,东方田鼠在拥挤的的压力下或直接被洪水所迫,越过防洪堤迁入垸内。东方田鼠在湖滩及农田间的迁移主要取决于湖水水位及种群密度,无固定的迁移时间。迁入垸内的东方田鼠主要分布于靠近防洪堤一带,其捕获率随着与防洪堤距离的增加而递减。个体较大的东方田鼠迁移距离较远。在迁移期,迁入垸内的东方田鼠的性比在不同的距离上无显著差异。湖水回落时,东方田鼠随湖滩出露而迁回沼泽草地。回迁时,个体较大的雄性首先回迁的比例较高。迁入垸内的东方田鼠,栖息在荒坡地的种群密度大于在农田中的种群密度;东方田鼠不在农田越冬,小部分可在岗地荒坡中越冬,但少有增殖。按迁移动因看,此种迁移乃洪水逼迫所至,而由逼迫外迁和自动回迁构成循环,保证了种群对湖区特殊环境的适应。     

Listeria monocytogenes contamination of crops grown on soil treated with sewage sludge cake

A l -G hazali , M.R. & A l -A zawi , S.K. 1990. Listeria monocytogenes contamination of crops grown on soil treated with sewage sludge cake. Journal of Applied Bacteriology 69 , 642–647.
Listeria monocytogenes was found in the sewage sludge cake which is commonly used as an agricultural fertilizer in Iraq. Soils treated with this material were contaminated with the organism. Pot and field experiment showed that crops grown on treated soil became contaminated with L. monocytogenes and when alfalfa plant was grown on farmland soil treated with sewage sludge cake, listerias were found on 10% of 50 plants sampled at harvest, but the organism was detected only in low numbers on these crops (≤ 5 cells/g). This could add to the risk to animals and man.     

ESR studies on the membrane properties of a moderately halophilic bacterium. II. Effect of extreme growth conditions on liposome properties

Lipid preparations from the cells of a moderately halophilic bacterium, Pseudomonas halosaccharolytica grown under the two extreme conditions of high temperature-high NaCl concentration and low temperature-low NaCl concentration showed distinctively different profiles in phospholipid and fatty acid composition. Cells grown at 40 degrees C in medium containing 3.5 M NaCl had high concentrations of saturated and C19 cyclopropanoic fatty acids (about 50 per cent of the total), whereas cells grown at 20 degrees C in medium containing 0.5 M NaCl had decreased concentrations of these fatty acids with increased concentrations of the corresponding unsaturated fatty acids. The phospholipid composition was also affected ty the culture conditions; cells grown at 40 degrees C in 3.5 M NaCl had large amounts of acidic phospholipids, whereas those grown at 20 degrees C in 0.5 M NaCl had small amounts. ESR studies on liposomes prepared from lipids of cells grown under the two conditions showed characteristic profiles for correlation times and order parameters of three spin labels of stearic acid derivatives similar to those of membranes of whole cells of this bacterium. ESR studies showed that the physical properties of the liposomes from the total extractable lipids and isolated phosphatidylglycerol from the cells were completely different from those of synthetic dioleoylphosphatidylglycerol. Liposomes of the lipids extracted from cells grown at 40 degrees C in 3.5 M NaCl showed change in rotational viscosity on altering the NaCl concentration to 0.5M, whereas liposomes of lipids extracted from cells grown at 20 degrees C in 0.5 M NaCl did not show change in rotational viscosity on increasing the NaCl concentration to 3.5 M.     

陕西榆林地区农田灯诱地下害虫种类组成及优势种群发生动态

为了明确陕西榆林地区农田地下害虫种类组成及优势种群发生动态,于2016年4月1日至2019年9月28日,在陕西省榆林市现代农业示范园,设置太阳能自动虫情测报箱对地下害虫进行收集,在室内对标本进行鉴定和数据分析。在榆林市农田一共灯诱到地下害虫12种,隶属3目5科。地下害虫混合种群发生期为4月中旬至9月上旬,盛发期为4月下旬至8月上旬。小地老虎Agrotis ypsilon、东方绢金龟Maladera orientalis、阔胫绢金龟Maladera verticalis和黄褐丽金龟Anomala exoleta是榆林农田地下害虫主要优势种群。小地老虎灯诱高峰期为4月上旬至5月中旬以及6月上旬至7月下旬,东方绢金龟的灯诱高峰期为4月中旬至6月中旬,阔胫绢金龟灯诱高峰期为6月上旬至8月上旬,黄褐丽金龟灯诱高峰期为6月中旬至7月上旬。本研究为榆林地区农田地下害虫的监测和综合治理提供了基础资料。     

Fatty acid oxidation and the beta-oxidation complex in Mycobacterium leprae and two axenically cultivable mycobacteria that are pathogens

Intact, non-growing Mycobacterium leprae, M. avium and M. microti oxidized a wide range of 1-14C-labelled fatty acids (C8 to C24) to 14CO2. Laurate (C12) was oxidized most rapidly, and its oxidation by M. leprae was inhibited by the antileprosy agents Dapsone, clofazamine and rifampicin. Key enzymes of beta-oxidation were detected in extracts from all three mycobacteria. All these activities (both in intact mycobacteria and the enzymes) were stimulated in M. avium grown in Dubos medium plus palmitate but activities in M. microti or M. avium grown either in Dubos medium with added liposomes or triolein, or in vivo were similar to those detected in the same strain grown in Dubos medium alone. M. avium could be grown in medium in which 95% of its fatty acyl elongase activity is acetyl-CoA dependent. In this medium growing M. avium organisms oxidized [1-14C]palmitate to 14CO2 but simultaneously elongated palmitate to C24 acids and even longer. Acetyl-CoA-dependent elongase activity is similar but clearly not identical to reversed beta-oxidation, but the exact point(s) of difference have not yet been identified.     

Factors influencing the chlorine susceptibility of Mycobacterium avium,Mycobacterium intracellulare,and Mycobacterium scrofulaceum

The susceptibility of representative strains of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum (the MAIS group) to chlorine was studied to identify factors related to culture conditions and growth phase that influenced susceptibility. M. avium and M. intracellulare strains were more resistant to chlorine than were strains of M. scrofulaceum. Transparent and unpigmented colony variants were more resistant to chlorine than were their isogenic opaque and pigmented variants (respectively). Depending on growth stage and growth rate, MAIS strains differed in their chlorine susceptibilities. Cells from strains of all three species growing in early log phase at the highest growth rates were more susceptible than cells in log and stationary phase. Rapidly growing cells were more susceptible to chlorine than slowly growing cells. The chlorine susceptibility of M. avium cells grown at 30 degrees C was increased when cells were exposed to chlorine at 40 degrees C compared to susceptibility after exposure at 30 degrees C. Cells of M. avium grown in 6% oxygen were significantly more chlorine susceptible than cells grown in air. Chlorine-resistant MAIS strains were more hydrophobic and resistant to Tween 80, para-nitrobenzoate, hydroxylamine, and nitrite than were the chlorine-sensitive strains.     

宁南山区紫花苜蓿(Medicago sativa)土壤干层水分动态及草粮轮作恢复效应

以各类作物农田水分为对照,连续两年对宁南山区不同生长年限苜蓿深层土壤水分以及10年生苜蓿地耕翻后轮作不同年份作物农田的水分进行了测定.结果表明,随着苜蓿生长年限的增加,干层深度与厚度先增加后减小.3年生苜蓿干层深度为720cm,6年生干层最深可达1000cm以下,10年生干层深度为920cm,3～12年生苜蓿地0～700cm土层基本上均属于土壤干层范围.苜蓿地0～800cm土壤湿度随生长年限增加而降低,2004年测定的4、7年生和12年生苜蓿地0～700cm土层平均含水率分别为5.30%、5.22%和5.01%;2005年测定的3、6年生和10年生苜蓿地0～800cm土层湿度分别为6.26%、5.60%和5.27%;而800～1000cm土层湿度在一定年限后有恢复趋势.300cm为苜蓿地降水下渗的最大临界深度,300cm以下土壤干层一旦形成,将长期存在,7～12年生苜蓿300～700cm土层湿度仅维持在4.0%左右.苜蓿地和农田的土壤干层厚度与湿度有较大差异,草粮轮作可使苜蓿土壤干层水分基本恢复到农田湿度,而且轮作年份越长,土壤各层次水分恢复效果越好,10年生苜蓿轮作18年后土壤水分基本恢复到农田状态.     

Possible association of GroES and antigen 85 proteins with heat resistance of Mycobacterium paratuberculosis

Conflicting reports on the heat resistance of Mycobacterium paratuberculosis prompted an examination of the effect of culture medium on this property of the organism. M. paratuberculosis was cultured in three types of media (fatty acid-containing medium 7H9-OADC (oleic acid-albumin-dextrose-catalase supplement) and glycerol-containing media WR-GD and 7H9-GD [glycerol-dextrose supplement]) at pH 6.0. M. paratuberculosis grown under these three culture conditions was then tested for heat resistance in distilled water at 65 degrees C. Soluble proteins and mycolic acids of M. paratuberculosis were evaluated by two-dimensional electrophoresis (2-DE) and thin-layer chromatography (TLC), respectively. The type of culture medium used significantly affected the heat resistance of M. paratuberculosis. The decimal reduction times at 65 degrees C (D(65 degrees C) values; times required to reduce the concentration of bacteria by a factor of 10 at 65 degrees C) for M. paratuberculosis strains grown in 7H9-OADC were significantly higher than those for the organisms grown in WR-GD medium (P < 0.01). When the glycerol-dextrose supplement of WR was substituted for the fatty acid supplement (OADC) in 7H9 medium (resulting in 7H9-GD), the D(65 degrees C) value was significantly lower than that for the organism grown in 7H9-OADC medium (P = 0.022) but higher than that when it was cultured in WR-GD medium (P = 0.005). Proteomic analysis by 2-DE of soluble proteins extracted from M. paratuberculosis grown without heat stress in the three media (7H9-OADC, 7H9-GD, and WR-GD) revealed that seven proteins were more highly expressed in 7H9-OADC medium than in the other two media. When the seven proteins were subjected to matrix-assisted laser desorption ionization-mass spectrometric analysis, four of the seven protein spots were unidentifiable. The other three proteins were identified as GroES heat shock protein, alpha antigen, and antigen 85 complex B (Ag85B; fibronectin-binding protein). These proteins may be associated with the heat resistance of M. paratuberculosis. Alpha antigen and Ag85B are both trehalose mycolyltransferases involved in mycobacterial cell wall assembly. TLC revealed that 7H9-OADC medium supported production of more trehalose dimycolates and cell wall-bound mycolic acids than did WR-GD medium. The present study shows that in vitro culture conditions significantly affect heat resistance, cell wall synthesis, and protein expression of M. paratuberculosis and emphasize the importance of culture conditions on in vitro and ex vivo studies to estimate heat resistance.