Study of the growth and development of chlorella populations in the culture as a whole

Индивидуальных реак ций Chlorella клеток в популя ции культуре различн ых plasmolytics представить док азательства в поддер жку мнения о том, что ж изненный цикл Chlorella клет ки является гораздо б олее сложным, чем В на стоящее время считае тся случай. Тонус о ку льтуре средних имеет заметное влияние на ж изненный цикл Chlorella клет ок. Больше их жизненн ого цикла, больше вер оятность их формиров ания более autospores. Экстраг ированный из клетки Содержание в среде, п ри определенных усло виях, указывает на то, что во время их жизне нный цикл клеток Chlorella мо жет пройти через polyplastid и, в озможно, multinuclear этапа.     

Study of the growth and development of chlorella populations in the culture as a whole

Исследовалась цитоморфология двух видов Chlorella в условиях, при которых наблудается в боляшей или меняцей степени циссоциация процессов роста и размножения. В средах различного состава можно было наблуюдатявполне тиничный и воспроизводимый характер (trend) роста и развития кулятуры как целого. Chlorella в основном размножается так, как размножаются клеточные ядра, митохондрии и пластиды. Из них и из их плазмы строятся постепенно сначала безоболочечные и поцвижные проаутоспоры, которые, приобретая оболочку, преврацаются в непоцвижные аутоспоры. Экбалаты и экбластаты —это различные формы ранних фаз развитня проаутоспор. Недостаток магния и серы вызывает быстроепрекрацение способности к размножению и преобладания роста в величниу в сравнении со способностяю водорослей к делению. Чрезмерный рост в величину у Chlorella является не признаком физиологического благополучия, а признаком дегенерации. При зтом Chlorella подвергается вакуолизации и позднее погибает, обычно в результате осмотического растягивания.     

Study of the growth and development of chlorella populations in the culture as a whole

Два питательных сре дств массовой инфор мации были подготов лены на который роста и разв ития популяцийChlorella pyrenoidosa и Chlorella vulgaris var. viridis Были биологиче скиже. На средних обо их видов же. На средних обоих в идов из клетки на две autospores, в то время от среднего числа ра зличных autospores были сформированы и з материнской клетки различных размеров. Chlorella protothecoides которая ведется в кол лекции только о средствах массовой информации, содержащ ие Витте или peptone дрожжевой экстракт, т акже вырос на средних B. Отдел двух бывших видов Chlorella было более интенсивным, чем на средних на средних     

Study of the growth and development ofChlorella populations in the culture as a whole

Colour tests for study of the nuclear apparatus ofChlorella cells are described. It can be concluded from the results thatChlorella cell nucleus contains a relatively large nucleolus; the peripheral layers of the nucleus are rich in chromatin only in the nuclear division phase. The nucleus divides by a simplified form of mitosis, characterized morphologically by simple constriction.     

Study of the growth and development of Chlorella populations in the culture as a whole

Исследование влияния различных ритмов чередования света и темноты на жизненный цикл популяции Chlorella в культуре как целом является удобным экспериментальным методом сравнительной ?изиологии размножения водоросли. В известных пределах внешних условий постановки опыта можно регулировать сложный процесс образования определенного количества автоспор в культуре Chlorella. С удлинением ?отопериода культура проявляет тенденцию к образованию олигонуклеарных и полипластидных клеток. Наоборот, с сокращением ?отопериода отдельные особи в культуре как целом проявляют в определенных предлах тенденцию к образованию олигопластидных полинуклеаров. В этом случае особенно бросается в глаза нарушение нуклеоплазматическ ого соотношения, и под микроскопом на свежих препаратах живых водорослей наблюдается интенсивиая экбластация. Все образования, возникающие путем экбаляции и экбластации, были обозначены общим названием the Pearsall-Loose’s bodies, а все красные образования в хлореллах – общим названием Beyerinck’s bodies, так как в основном эти авторы распознали их еще до нас.     

Improved growth and development of presomite mouse embryos in whole embryo culture

A rotator whole embryo culture system was used to assess the growth and development of late-primitive-streak-stage (Theiler stage 9-10) mouse embryos to the limb-bud stage of organogenesis in a variety of media containing combinations of mouse serum (MS), rat serum (RS), and Tyrode's buffer (TB). The results demonstrate that embryonic growth and morphogenesis to the early limb-bud stage (20 somite pairs; 48-h total culture period) mimicked that in vivo when embryos were grown for 24 h in combinations of MS:RS:TB 1:2:1 or 2:1:1 (v/v/v) and then were transferred to fresh medium containing RS:TB 3:1 at the early somite stage. When the culture period was extended for an additional 24 h (total 72-h culture period) embryonic growth retardation was observed. Regardless of the medium employed, superior growth was observed in embryos transferred at the early somite stage when compared to embryos cultured continuously in the same medium for the entire 48- or 72-h culture period.     

Chitosan as a growth stimulator in orchid tissue culture

The effect of shrimp and fungal chitosan on the growth and development of orchid plant meristemic tissue in culture was investigated in liquid and on solid medium. The growth of meristem explants into protocorm-like bodies in liquid medium was accelerated up to 15 times in the presence of chitosan oligomer, the optimal concentration being 15 ppm. The 1 kDa shrimp oligomer was slightly more effective compared to 10 kDa shrimp chitosan and four times more active compared to high molecular weight 100 kDa shrimp chitosan. The 10 kDa fungal chitosan was more effective compared with 1 kDa oligomer. The development of orchid protocorm into differentiated orchid tissue with primary shoots and roots was studied on solid agar medium. The optimal effect, the generation of 5–7 plantlets in 12 weeks was observed in the presence of 20 ppm using either 10 kDa fungal or 1 kDa oligomer shrimp chitosan. The data are consistent with preliminary results from field experiments and confirm unequivocally that a minor amount of chitosan has a profound effect on the growth and development of orchid plant tissue.     

Muscle cell culture as a tool in animal growth research

Muscle cell culture techniques have been used for several years in research on muscle growth and development. Several types of culture systems have been devised, including primary cultures from embryonic or postnatal muscle and myogenic cell lines. In addition, serum-free and serum-containing media have been developed to address specific muscle development questions. Many of these questions center around muscle cell differentiation and muscle cell physiology; and, more recently, muscle cell cultures have been used as bioassay tools for examining growth physiology in domestic animals. In our laboratory, skeletal muscle satellite cells have been studied in vitro to evaluate the effect of several protein hormones and growth factors on satellite cell proliferation and differentiation. Of the hormones examined, only the insulin-like growth factors/somatomedins and fibroblast growth factor have been shown to have a stimulatory effect on proliferation that could be physiologically significant. None of the major anterior pituitary hormones interacted directly with satellite cells to stimulate proliferation. With advances in serum-free medium formulations and cell separation techniques, more information can be obtained from experiments with muscle cell cultures. With appropriate design and interpretation, our knowledge of muscle growth in domestic animals will be expanded.     

Chlorophyll synthesis in chlorella I. Occurrence of a lag phase on initiation of a dilute culture

A culture of Chlorella established by 30-fold dilution of a culture already grown to a level of 15 ml packed cell volume per liter produces little chlorophyll for approximately 12 hours. Investigation of other characteristics such as nitrogen incorporation, increase in packed cell volume and dry weight as well as RNA level show all of these to increase without any significant lag. α-Linolenate, which can be considered as a chloroplast marker, increased markedly. Photosynthetic oxygen evolution and respiration as well as the heme enzyme, catalase, increase also, indicating that the lag in chlorophyll synthesis is not due to a general inability to produce the porphyrin moiety.     

一株重金属镉耐受小球藻的分离鉴定及其生长条件优化

以龙江河镉污染水体预留样本为实验材料,从中筛选得到一株重金属镉耐受藻株,经形态和分子生物学鉴定为小球藻属,命名为Chlorella sp.LQQ-1。实验从温度、pH、Cd²⁺、有机碳源及有机氮源等方面对该藻株生长条件进行优化,并考察其在最佳生长条件下对水体中Cd²⁺的去除效果。结果表明:该小球藻最适宜生长温度为30℃,最适宜pH为7.0左右。Cd²⁺在低浓度下能促进小球藻的生长,当Cd²⁺浓度超过30μmol·L^-1时,小球藻的生长受到抑制。适宜该小球藻生长的最佳葡萄糖添加浓度为10g·L^-1,最佳尿素添加浓度为1g·L^-1。在最佳生长条件下,该小球藻对水体中Cd²⁺的去除率达89.7%。     

The development of photosynthesis in a greening mutant of chlorella and an analysis of the light saturation curve

Photosynthetic oxygen evolution considerably precedes the rise in chlorophyll during the greening of a yellow mutant of Chlorella vulgaris. Dark-grown cells required 20 times more light to saturate photosynthesis than light-grown or normal cells. The chlorophyll appears to add first to active reaction centers, then to fill in a more general antenna. The carotenoid pigments seem to add more randomly to the reaction centers. The shape of the light saturation curves can be explained with the assumption that an excitation in the antenna can reach several reaction centers. The efficiency of the total unit is constant during the greening process.     

Study of the oxygen effect during growth of a bacterial culture

In study of the oxygen effect in relation to the growth curve ofEscherichia coli B, its size was found to be correlated to the stage of growth at which the bacteria were irradiated. The lowest dose reduction factor value (DRF = 1.5) was found with bacteria irradiated at the outset of the logarithmic phase and the highest value (DRF = 2.7) with bacteria in the stationary phase. This phenomenon was observed both in a culture cultivated under aerobic conditions prior to irradiation and in a culture cultivated under anaerobic conditions. The cultivation conditions influenced only the radiosensitivity of the bacteria.     

Fibroblast growth factor levels in the whole embryo and limb bud during chick development

A growth factor with properties very similar to fibroblast growth factor (FGF) was detected in the yolk and white of unfertilized chick eggs, and in the limb bud and bodies of Day 2.5 (stage 18)-13 chick embryos using two complementary and highly sensitive biological assays-competition of 125I-a-FGF binding to the FGF receptors of 3T3 cells and stimulation of DNA synthesis in MM14 cells, a permanent mouse skeletal muscle cell line that is dependent upon FGF for proliferation. Further evidence of the similarity of this growth factor to FGF is provided by the finding that biological activity is lost when the material is bound to a heparin-Sepharose column and restored upon elution with 2.5 M NaCl; the 2.5 M NaCl fraction from Day 12 embryos contains several polypeptides of apparent molecular weights 12,500-17,500. The level of FGF in the embryonic chick body is fairly constant between Days 2.5 and 6 (stages 18-29), ranging between 1 and 2 ng FGF/mg protein; but thereafter the level increases so that by Day 13 the body contains about 15 ng FGF/mg protein. In contrast, the level of FGF in the limb but is higher than that in the rest of the body until Day 5 (stage 27); it then undergoes a transient decrease between Days 6 and 7, after which it increases but remains below the level observed in the remainder of the body.     

Humid acid influence on the growth and copper tolerance of chlorella sp.

The authors describe and discuss experiments carried out withChlorella sp. in which the effect of humic acid on its growth was studied. Also the coupled effect of humic acid and tolerance to cupric ions was demonstrated. Some ecological implication are discussed.     

Identification of a stage-specific permissive in vitro culture environment for follicle growth and oocyte development

The availability of viable oocytes is the limiting factor in the development of new reproductive techniques. Many attempts have been made to grow immature oocytes in vitro during recent decades. Recently, a modified alginate-based three-dimensional culture system was designed to support the growth and maturation of multilayered secondary follicles. This system was able to produce oocytes that successfully completed meiosis, fertilization, and development to the blastocyst stage. Subsequent attempts to culture two-layered secondary follicles were unsuccessful under the original conditions. Herein, we investigated the effect of alginate consistency on two-layered follicle growth and oocyte developmental competence by encapsulating follicles into alginate scaffolds of various concentrations. Although there were no significant differences in survival rates, 0.25% and 0.5% alginate supported more rapid growth of follicles and antrum formation compared with 1.5% and 1.0% alginate after 8 days of culture. Alginate scaffold concentration also affected the proliferation and differentiation of somatic cells (theca and granulosa cells), measured in terms of morphological changes, steroid profiles (androstenedione, estradiol, and progesterone), and specific molecular markers (Fshr, Lhcgr, and Gja1). Theca cell proliferation and steroid production were hindered in follicles cultured in 1.5% alginate. In vitro fertilization and embryo culture revealed that oocytes obtained from 0.25% alginate retained the highest developmental competence. Overall, the present study showed that the alginate scaffold consistency affects folliculogenesis and oocyte development in vitro and that the alginate culture system can and should be tailored to maximally support follicle growth depending on the size and stage of the follicles selected for culture.     

Hybridoma growth and antibody production as a function of cell density and specific growth rate in perfusion culture

Steady state metabolic parameters for hybridoma cell line H22 were determined over a wide range of cell densities and specific growth rates in a filtration based homogeneous perfusion reactor. Operating the reactor at perfusion rates of 0.75, 2.0, and 2.9 day(-1)(each at four different specific growth rates), viable cell densities as high as 2 x 10(7) cells/mL were obtained. For the cell line under investigation, the specific monoclonal antibody production rate was found to be a strong function of the viable cell density, increasing with increasing cell density. In contrast, most of the substrate consumption and product formation rates were strong functions of the specific growth rate. Substrate metabolism became more efficient at high cell densities and low specific growth rates. The Specific rates of metabolite formation and the apparent yields of lactate from glucose and ammonia from glutamine decreased at low specific growth rates and high cell densities. While the specific oxygen consumption rate was independent of the specific growth rate and cell density, ATP production was more oxidative at lower specific growth rate and higher cell density. These observed shifts are strong indications of the production potential of high-density perfusion culture. (c) 1995 John Wiley & Sons, Inc.     

Structure and function of a chlorella virus-encoded glycosyltransferase

Paramecium bursaria chlorella virus-1 encodes at least five putative glycosyltransferases that are probably involved in the synthesis of the glycan components of the viral major capsid protein. The 1.6 A crystal structure of one of these glycosyltransferases (A64R) has a mixed alpha/beta fold containing a central, six-stranded beta sheet flanked by alpha helices. Crystal structures of A64R, complexed with UDP, CMP, or GDP, established that only UDP bound to A64R in the presence of Mn(2+), consistent with its high structural similarity to glycosyltransferases which utilize UDP as the sugar carrier. The structure of the complex of A64R, UDP-glucose, and Mn(2+) showed that the largest conformational change occurred when hydrogen bonds were formed with the ligands. Unlike UDP-glucose, UDP-galactose and UDP-GlcNAc did not bind to A64R, suggesting a selective binding of UDP-glucose. Thus, UDP-glucose is most likely the sugar donor for A64R, consistent with glucose occurring in the virus major capsid protein glycans.