CULTURE CONDITIONS AND THE DEVELOPMENT OF THE PHOTOSYNTHETIC MECHANISM : II. AN APPARATUS FOR THE CONTINUOUS CULTURE OF CHLORELLA

1. An apparatus has been developed which maintains a constant density of population of Chlorella by automatic dilution of the growing culture with fresh medium. 2. Cells harvested from the apparatus in daily samples are highly uniform in rate of growth and rate of photosynthesis measured under arbitrarily chosen conditions.     

基于人工培养的浮萍快速无性繁殖营养条件研究

为探究并优化浮萍人工培养技术, 研究以广布种紫萍(Spirodela polyrrhiza)和青萍(Lemna minor)为主要研究对象, 探索两种浮萍植物在不同营养水平的Hoagland和Hunter培养液中的鲜重、叶状体数的生长变化状况。结果表明: (1)紫萍和青萍鲜重在Hoagland培养液的不同营养水平下先增加后减少, 而在Hunter营养液中呈持续增长趋势; 两种浮萍的鲜重最大相对增长率(RGR)分别为0.11和0.18, 鲜重受浮萍品种和培养基类型及其不同营养水平影响显著(P<0.05), 以青萍在Hunter原液培养基下的无性繁殖产生的生物量最高。(2)紫萍和青萍叶状体数在Hoagland培养液的不同营养水平下先增加后减少, 而同鲜重一样在Hunter营养液中呈不断增长趋势; 两种浮萍的叶状体最大相对增长率分别为0.14和0.19, 叶状体生长的RGR变化同样受浮萍品种和培养基类型及营养水平影响显著(P<0.05), 以青萍在Hunter原液的营养环境下收获的叶状体数最高。(3)两种浮萍在Hoagland和Hunter营养液的不同营养水平下鲜重/叶状体比呈下降趋势, 表明两种浮萍在适应不同营养时优先繁殖子代叶状体, 以扩大种的适合度。研究认为Hunter原液可作为广布种青萍的最优培养条件, 可实现短时间内收获较大浮萍鲜生物量和叶状体数, 为进一步资源化利用提供原材料。     

用模式识别法优化微生物培养基的营养条件

应用模式识别方法,对微生物培养的营养条件进行优化。以培养基组成构筑模式空间,通过主成份分析（ＰＣＡ）揭示模式空间的可视优化区,建立模式分类器并道推回到高维空间得到最佳培养基组成。以锌酵母为例。介绍优化全过程。     

绿僵菌产海藻糖水解酶培养条件研究

丝状真菌绿僵菌能产生一系列二糖水解酶,其中包括海藻糖水解酶。这些酶在绿僵菌对昆虫的致病过程中起着重要的作用。本文研究了不同碳源、氮源对金龟子绿僵菌Metarhizium anisopliae var. acridum菌株CQMa102产生与分解昆虫血淋巴中海藻糖等二糖相关的海藻糖水解酶活性的影响。结果表明:分别以葡萄糖、麦芽糖、蔗糖、山梨醇和可溶性淀粉为碳源,金龟子绿僵菌均可产生海藻糖水解酶,但最佳碳源是可溶性淀粉,因为由其诱导产生的海藻糖水解酶具有最高的总活性和比活性以及更多的同工酶,山梨醇次之。硝态氮(NaNO₃)作为唯一氮源时,几乎检测不出海藻糖水解酶活性,而铵态氮((NH₄)₂SO₄)或NaNO₃和有机氮(蛋白胨和酵母浸膏)混合氮源作氮源时,海藻糖水解酶活性都很高。在绿僵菌菌丝提取液和滤液的海藻糖水解酶活性比较中发现:CQMa102在多数碳源的培养基中产生的海藻糖水解酶主要分泌到培养基中,仅有少数结合在细胞壁上。     

金针菇菌丝生长的营养需求及液体发酵研究

金针菇菌丝体液体培养表明,淀粉、玉米粉是适宜的碳源,黄豆粉、酵母粉、蛋白陈是适宜的氮源。采用正交设计考察了培养基的营养成分及其最适浓度。除碳、氮源外,Vb1及K、P、Mg、S等元素也是金针菇菌丝体生长所必需的营养因子。适宜的碳氮比（C/N.）为21～24：1。本研究建立的有实用价值的液体发酵培养基配方是（％）：玉米粉4.0、葡萄粉1．0～2.0、黄豆粉15、KH₂PO₄0.1～0．15、MgSO₄·7H₂O0.05     

STRUCTURAL DEVELOPMENT OF THE CAUDICLE OF AN ORCHID (EPIDENDRUM)

Structural changes during development of the caudicle of Epidendrum ibaguense (Orchidaceae) were followed using light and electron microscopy. The caudicle begins as a mass of small meristematic cells in the microsporangium. The central cells of the mass enlarge and enter a division cycle. Completion of this cycle produces linear tetrads of cells which remain attached to each other throughout the life of the caudicle. These tetrads then accumulate a thick secondary wall on their outer surfaces. These thick-walled cells form the main structural element of the caudicle at maturity. The cells on the periphery of the mass differentiate into a gradation of cell types characterized by their very high content of smooth ER. The majority of these thin-walled cells are located at the junction points between adjacent caudicles and between caudicle and pollinium. The cells in these positions produce large quantities of a lipid polymer. This product is synthesized in association with large tubular ER complexes present in discrete areas in the cytoplasm. Plastids of these cells also produce a lipidic substance. Some thin-walled cells are located among the thick-walled structural cells; however, the lipid polymer is not synthesized in these cells. At maturity, all thin-walled cells undergo breakdown and autolysis resulting in gradual obliteration of cytoplasmic detail and organelles. In the lipid containing thin-walled cells, lysis of the cells releases the lipidic masses which then form the elastic joining compound between adjacent caudicles and between caudicles and pollinia.     

THE NUMBER OF ASSESSORS REQUIRED FOR TASTE PANELS

Consideration of the difference in taste between two samplesas a variable leads to estimates of variance. Any minimum differencein taste scores can be detected if a large enough number ofassessors is used. ^* Contribution from the Agricultural Research Organization,The Volcani Center, Bet Dagan, Israel. 1976 Series, No. 271-E.     

培养条件下发菜的形态建成

固体培养基培养的发菜(Nostoc flagelliforme)在黑暗与低光强(2·s)条件下细胞发育受到抑制,在光强10、20、30、60 μmol/m2·s 条件下细胞生长良好, 但在60 μmol/m2·s 条件下藻丝体易变黄; 液体充气培养的发菜在光强20、60、180 μmol/m2·s 条件下生长速率、类胡萝卜素与多糖含量均随光强升高而增加。发菜在低营养水平时形成的异形胞较多, 异形胞的发生位置也多样, 有端生、间生和连生。当琼脂浓度为0.5%—4%时发菜具有相同的形态发育特征, 从藻殖段发育至丝状聚集体状态, 再从聚集体中释放藻丝; 当琼脂浓度为6%—8%时发菜发育至丝状聚集体状态, 藻丝包裹在厚胶鞘中, 观察不到藻丝和藻殖段的释放。以上结果表明光照和培养基的含水量对发菜细胞发育具有重要影响。       

灰树花深层发酵工艺条件的研究

灰树花摇瓶发酵较佳条件 :QF培养基 ,2 5℃ ,pH4 5,装量 60mL/50 0mL三角瓶 ,转速 1 0 0r/min。在种子培养基中加 0 4%的CMC ,可增加种子液菌丝的生长点 ,从而提高菌丝量。在 1 0L气升式发酵罐上放大试验 ,菌丝量对初糖的生物转化率在 2 4 %以上 ,对耗糖的转化率达 435%。菌丝体中多糖含量达 1 0 2 % ,发酵液中多糖含量为 1 38%。     

DURATION OF LIFE OF AN ASEPTIC DROSOPHILA CULTURE INBRED IN THE DARK FOR 230 GENERATIONS

The number of pupæ formed per female, the duration of the larval period, and the duration of the pupal-imago period of a normal Drosophila culture and of the 230th generation of an aseptic culture which had been kept in the dark have been determined. The larval period and the pupal-imago period were found to be nearly the same for both cultures under both favorable and unfavorable conditions. There is no evidence, therefore, to show that inbreeding, absence of light, or growth in the absence of bacteria for 230 generations has had any effect either on the duration of life or on the ability of the organism to resist unfavorable bacteria.     

CULTURE OF MATURE ECOTYLEDONOUS EMBRYOS OF PHASEOLUS VULGARIS AND THE NUTRITIONAL ROLE OF COTYLEDONS

Embryos of Phaseolus vulgaris L. were excised from seeds and cultured with cotyledons removed to determine the actions of various cultural conditions upon embryo development. Four media were tested, but ecotyledonized embryos did not grow as rapidly on any of them as did embryos with intact cotyledons on agar-water media. Comparisons of growth of ecotyledonized embryos with embryos bearing fractions of cotyledons indicated ecotyledonized embryos cultured on nutrient media grew about as well as embryos bearing cotyledons from which 97% of the volume had been removed surgically. The final weight of ecotyledonized embryos was greater when detached cotyledons were placed near them and was even greater when extracts of detached and incubated cotyledons were employed in the nutrient medium. Benzyladenine, kinetin, gibberellic acid, indole-acetic acid, presence of sucrose, and light or dark culture failed to enhance the ability of incubated cotyledons to stimulate growth of embryos.     

神经细胞老化实验研究模型:无血清条件下培养小鼠神经母细胞瘤细胞

本文报道的在无血清条件下培养小鼠神经母细胞瘤细胞,应用显微荧光光度测定法来定量观察脂褐素自发荧光现象的增长,是神经细胞老化实验研究一种实用的模型,可适用于多种基础或应用的研究。我们认为对某些细胞株,在适用的实验研究情况下,应用较简单的无血清培养条件完全是可以实行的,应该提倡推广。     

白菜黑斑病菌三个种菌株基本培养条件比较

选用来自国内外的白菜黑斑病菌三个种Alternaria brassicicola,A. brassicae和A. japonica为研究材料,以生长速率为评价指标,对其适宜生长温度、pH值、光照、培养基和菌落特征等基本培养条件和性状进行了对比研究。结果表明,三个种的病菌最适生长温度均在20℃～25℃,变化幅度较小,但A. brassicicola 和A. japonica菌丝体生长温度范围和已有文献报道相比提高了5℃;A. brassicae中国菌株菌丝体生长的pH值范围为4~8,其它所有供试菌株生长的pH值为3~11;24h光照、12h光暗交替和24h黑暗对国内外A. brassicicola菌株生长速率影响均不大,而A. brassicae在24h光照和12h光暗交替下的生长速率比24h黑暗处理的显著增大,24h光照和24h黑暗比12h光暗交替更适合A. japonica生长;PDA是白菜黑斑病菌营养生长的最适培养基,SNA除了适合其生长外,还对供试三个种的病菌生长有选择性;菌落直径及颜色可以作为区分三个种的参考指标。供试的白菜黑斑病菌三个种在基本培养条件方面存在种水平上的差异。     

初始培养条件对定兴芥小孢子胚胎发生的影响

本文探索了油菜花药培养中小孢子胚早期发育的适宜条件。花药分步悬浮法第一培养基的简化实验表明,小孢子胚在仅含有20%蔗糖的空白培养基上的诱导率(212%)与对照的(202%)无显著差异。这样,第一培养基便从原Keller培养基简化为不含大量、微量和有机元素而仅含有20%蔗糖的水溶液,并且,花药第一阶段的培养时间从原来的3—5天减少到1.5—2天。此外,研究了花药在蔗糖水溶液上的滞留时间对小孢子胚胎早期发育的影响。滞留36～48小时,小孢子胚的诱导率(135%)最佳。考察小孢子胚胎早期发育的状况与不同滞留时间的关系则发现,36—48小时内每100个活细胞里,膨大细胞约占70%。这表明,早期培养时,花粉只要膨大而不需分裂即可转入第二阶段培养,便可获得较高产率的胚状体。     

AN UNUSUAL METHOD FOR CULTURE OF UNICELLULAR MARINE ALGAE1

A method for the axenic culture of marine microscopic algae that utilizes various types of paper as solid substrates for growth is described. Investigations into the growth of 39 algal, strains on various paper substrates were conducted. Applications of the method to bioassay are discussed.     

OPTIMIZATION OF CULTURE CONDITIONS FOR ENUMERATION OF H2S BACTERIA IN THE FLESH OF SEAFISH

H₂S bacteria of seafish flesh are weakly halophilic and require on average 1.68% NaCl according to statistical studies. Enumeration is optimal on PCA-H₂S(a PCA medium supplemented with sulfur sources and increased NaCl concentrations) incubated at 25C. Total aerobic bacteria can be counted simultaneously on this medium. The proportion of H₂S bacteria relative to total aerobic bacteria increased slightly during prolonged storage of the fish, but was highly variable. Models relating H₂S bacterial counts to spoilage of fish are sigmoidal and showed that when the count exceeds 10,000 CFU/g, whole or filleted fish stored in ice at 0C are unfit for consumption. Shewanella putrefaciens accounted for 69% of the H₂S bacteria at the fifth day of storage and 100% at the fifteenth.     

培养条件对头孢霉菌丝体脂肪酸组分的影响

研究了头孢霉(Cephalosporium sp.)菌丝体最大生产力和多不饱和脂肪酸形成积累的条件。菌丝体最适培养条件为：麦芽糖60g/L\,KNO33g/L、起始pH为60、500mL三角瓶装100mL培养基、接种25%、25℃培养10d则菌丝体达到最大干重。多不饱和脂肪酸形成积累的最适条件为：葡萄糖10～20g/L、(NH4)2SO4或NH4Cl 3g/L、培养基起始pH为40、500mL三角瓶装100mL培养基、接种10%～20%、10℃下照光培养。〖JP2〗因此,在整个生产流程中可采用不同条件分段掌握的技术原则。同时提出在多不饱和脂肪酸的形成和积累途径中油酸(18∶1)向亚油酸(18∶2)的转化是关键,为进一步探索最适培养条件和关键酶的调节提供依据。