刘家峡水库网箱养鱼场纤毛虫群落特征

2006年3月至2007年2月, 用活体观察法和直接计数法对刘家峡水库网箱养鱼场纤毛虫群落进行了研究.共鉴定到77种纤毛虫, 其中包括4个未定名种, 隶属于3纲11目34科43属.下毛目为优势类群, 前口目为次优势类群, 异毛目为偶见类群.善变膜袋虫、长圆膜袋虫、珍珠映毛虫、钩刺斜管虫和大口瞬目虫为春季群落优势种; 善变膜袋虫、颗粒膜袋虫和珍珠映毛虫为夏季群落优势种; 颗粒膜袋虫和善变膜袋虫为秋季群落优势种; 冬季无明显优势种.纤毛虫物种数的周年动态呈单峰型, 8、9月份物种数最多, 有52种, 3月份最少, 只有18种; 物种数的季节动态为: 夏季＞秋季＞春季＞冬季.纤毛虫丰度的周年动态呈三峰型, 高峰分别出现在4月、6月和9月份, 5月份采样前夕水库调水导致丰度骤降是造成三峰型的主要原因; 纤毛虫丰度的季节动态为: 夏季＞秋季＞春季＞冬季.纤毛虫物种多样性指数的周年动态为: 8月份最大, 3月份最小.相关性分析结果表明, 对网箱养鱼场纤毛虫物种数影响最大的因子是水温, 其次是透明度和pH值, 投放饲料量的影响最小; 对网箱养鱼场纤毛虫丰度影响最大的是投放饲料量, 其次是水温和pH值, 透明度的影响最小.     

Abrupt increase in UV sensitivity at late log-phase of growth in Paramecium tetraurelia

In this study, changes in UV sensitivity, a parameter of the clonal aging that has been studied in the daily reisolation culture, were examined in the logarithmically growing Paramecium culture. Cells in logarithmically growing cultures are thought to change the internal states under rapidly changing external conditions. In contrast, cells in daily reisolation cultures gradually change the internal states, the process being called clonal development and aging, under the external conditions that are kept almost constant. Cells were sampled at regular intervals, irradiated with UV, and examined for UV sensitivity assessed by the clonal survival. We found that log-phase cells showed low sensitivity to UV until they reached 2,000-3,000 cells/ml, and beyond that cell density, abruptly became highly UV sensitive. The extent of this increase in UV sensitivity was similar to that between two age groups, 130 fissions of clonal age apart. When cells from a culture of 2,000-3,000 cells/ml were resuspended in culture medium at various cell densities, they changed to UV sensitive only when the cultures reached over approximately 2,600 cells/ml. These results suggest that paramecia become UV sensitive in response to change in the nutrient level when cell density exceeds 2,000-3,000 cells/ml.     

Ability of various inserts to promote endothelium cell culture for the establishment of coculture models

To select an insert suitable for human umbilical vein endothelial cell (HUVEC) culture, we compared several available inserts of 0.2 to 0.45 m porosity: Cellagen (ICN), Transwell-COL (Costar), Millicell-HA and CM (Millipore), Anopore (Nunc), Cyclopore (Falcon) in comparison with a control surface (Thermanox). The requirements were: (i) to promote attachment, adhesion and proliferation of HUVEC (judged by [³H]thymidine incorporation into DNA at days 1, 3, 7); (ii) to allow HUVEC visualization by inverted, fluorescence microscopy for uptake of DiI-Ac-LDL and scanning electron microscopy, performed at day 9 after seeding.Because Transwell and Cellagen are collagen precoated and CM has to be coated for cell culture, we performed collagen coating (types I + III or IV) for non-pretreated inserts for the purpose of comparison. Our preferences comprise Transwell-COL, Cyclopore not coated or coated (whatever the collagen type), and Cellagen. However, on a quality/price ratio criterion, Cyclopore, even uncoated, is the insert of choice. The HA, CM and Anopore inserts, even coated, do not allow HUVEC growth but do not alter positive uptake of acetylated LDL.Abbreviations HUVEC human umbilical vein endothelial cells     

A novel soft sensor approach for estimating individual biomass in mixed cultures

Due to many advantages associated with mixed cultures, their application in biotechnology has expanded rapidly in recent years. At the same time, many challenges remain for effective mixed culture applications. One obstacle is how to efficiently and accurately monitor the individual cell populations. Current approaches on individual cell mass quantification are suitable for off‐line, infrequent characterization. In this study, we propose a fast and accurate “soft sensor” approach for estimating individual cell concentrations in mixed cultures. The proposed approach utilizes optical density scanning spectrum of a mixed culture sample measured by a spectrophotometer over a range of wavelengths. A multivariate linear regression method, partial least squares or PLS, is applied to correlate individual cell concentrations to the spectrum. Three experimental case studies are used to examine the performance of the proposed soft sensor approach. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:347–354, 2017     

Genotypic variation in anther culture and effect of ovary coculture in durum wheat

The response of anthers to in vitro culture and the effect of coculture of ovaries on anther culturability have been studied in responsive and recalcitrant cultivars of durum wheat (Triticum turgidum ssp. durum) from Morocco and ICARDA. A large genotypic-dependence of anther culture has been shown in 18 cultivars. Their response in term of callus and embryo induction varied from 0 to 13%. Coculture of ovaries with anthers enhanced the response of the most responsive genotype (cv. Sarif) and removed the recalcitrance in Cocorit and Isly cultivars. However, there was no effect of anther-ovary coculture on green plant regeneration. The implication of the genome and the media conditioning by the ovaries on anther response is discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Potentiation of the destructive effect of heat (42°C) on synchronized cancer cells in culture by cell specific antiserum

1. 1. A kinetic study was made of the effects of hyperthermia and cell specific antibody on non-synchronized lag phase cultures and synchronized exponentially growing cultures of a malignant cell line. The effects on the degree of cell synchrony were also investigated.

2. 2. Hyperthermic treatment of synchronized SDB monolayer cell populations with maximum replication rate sensitized the cells to subsequent destruction by cell specific antibody.

3. 3. Hyperthermic treatment of SDB monolayer cultures with low replication rate and varying degrees of metabolic activity produced no such sensitization.

4. 4. Hyperthermia was disruptive to a synchrony procedure involving a blockade of DNA synthesis by excess thymidine.

Cell biology of deep-sea multicellular organisms

Establishing tissue cultures derived from deep-sea multicellular organisms has been extremely difficult because of the serious damage they sustain upon decompression and exposure to the high temperature of surface seawater. We developed a novel pressure-stat aquarium system for the study of living deep-sea multicellular organisms under pressure. Using this system, we have succeeded in maintaining a variety of deep-sea multicellular organisms under pressure and atmospheric conditions after gradual, slow decompression. Furthermore, we successfully cultivated and freeze-stocked pectoral fin cells of the deep-sea eel Simenchelys parasiticus collected at a depth of 1,162 m under atmospheric pressure conditions. This review describes novel capture and maintenance devices for deep-sea organisms and cell culture studies of the organisms under atmospheric and pressure conditions.     

Isolation of functional human trophoblast cells and their partial characterization in primary cell culture

Summary Human trophoblast isolation and cell culture procedures were examined to identify variables that enhance secretion of chorionic gonadotropin (HCG) in primary culture. Brief exposure of unminced first-trimester placental specimens to a solution of trypsin-EDTA-DNAse, and isolation of the dispersed cells after Ficoll-hypaque centrifugation yielded primary cultures that were high in HCG secretion and content of epithelial-like cells. The gradual decline in HCG level with time in monolayer culture in these presumptive trophoblast cells was retarded by treatment with theophylline and cyclic adenosine monophosphate. Exposure to methotrexate (MTX) did not increase HCG secretion in normal trophoblast cells, in contrast to a 5-fold stimulation by MTX in the JAR line of choriocarcinoma cells. Clusters of polygonal cells in primary culture progressively lost their capacity to secrete HCG and their epithelial-like morphology. However, they could be maintained as cell strains through approximately 15 passages over a period of 13 to 16 weeks.     

Monolayer culture of cells originating from apreimplantation bovine embryo

Summary The objective of this study was to establish a method by which trophectodermal cells originating from individual preimplantation bovine embryos could be perpetuated in monolayer culture. A single, Day-11 bovine embryo collected nonsurgically from a mixed-breed beef cow was cultured in Ham's F10 medium supplemented with fetal bovine serum, sodium pyruvate, insulin and epidermal growth factor. After 13 d in culture the embryo had adhered to the surface of the plastic culture vessel and a monolayer covering 0.3 cm² had developed in the manner of a tissue explant. The monolayer was successfully dispersed using trypsin-EDTA and the cells were passaged Expansion to a 25-cm² flask was achieved by the 4th passage. By passaging cultures at a dilution ratio of 1∶2, cells were maintained for 38 passages before growth slowed. Transfers beyond the 44th passage were unsuccessful. The cell line, designated BE-13, was successfully frozen and thawed at the 9th, 12th, 15th, and 20th passages. The cell line contains both mono- and binucleate cells with a prominent rough endoplasmic reticulum characteristic of ruminant trophoblast cells. Susceptibility to eight bovine viruses was demonstrated. Such cell lines may provide inexpensive systems for the study of trophoblast metabolism and for investigation of the role of the trophoblast in the pathogenesis of selected bovine abortifacient diseases. Because of their range of viral susceptibility, these cells might also be useful for diagnostic purposes. Published as publication no. 1891 College of Veterinary Medicine, Auburn University, Alabama 36849. This work was funded in part by an Auburn University Faculty Research Grant-in-aid. Preliminary results of the study were presented in abstract form at the 1987 Annual Conference of the International Embryo Transfer Society.     

Preparation of highly purified cytotrophoblast from human placenta with subsequent modulation to form syncytiotrophoblast in monolayer cultures

Summary The preparation of highly purified monolayer cultures of human cytotrophoblast cells essentially free of stromal and syncytial cells is described. Such cells subsequently form multinucleate syncytial cells in vitro. This is accompanied by the synthesis of heat-stable alkaline phosphatase and β-HCG. A significant proportion of the multinucleate cells that form in monolayer cultures of early placentae arise as a result of an amitosis. It is suggested that this in vitro behavior may reflect an in vivo process. C. Cotte is supported by a grant from C.D.C.H., Universidad Central de Venezuela.     

An Energy Analysis of Extracellular Hyperthermia

The classical hyperthermia effect is based on well‐focused energy absorption targeting the malignant tissue. The treatment temperature has been considered as the main technical parameter. There are discussions about the mechanism and control of the process because of some doubts about the micro‐mechanisms. The main idea of the extracellular hyperthermia is to heat up the targeted tissue by means of electric field, keeping the energy absorption in the extracellular liquid. This produces a temperature gradient and connected heat flow through the cell membrane, which initializes numerous nonequilibrium thermal microprocesses to destroy the cell membrane. Furthermore, before the heat shock activates the intracellular heat shock protein (HSP) mechanisms, thecell membrane has been already compromised, therefore the HSP synthesis in the cells starts secondarily only after the membrane damage. The process could explain why the nonuniform and basically unsatisfactorily high temperature locoregional hyperthermia could be effective.     

New orientations of in vitro models: why? how?

From the beginning of cell cultures, the aim of all researchers has been to perform culture of a pure population of a particular cell type. However, the monolayer culture (of one type of cell) rapidly showed its limits concerning growth capacity and especially maintenance of the differentiated functions. These findings led to the design of increasingly complex in vitro models. Among them we can distinguish culture onto cellular matrices and into cellular matrices, or tridimensional cell culture. Cocultures in two-compartment dishes or one-compartment dishes, heteroculture, and tissue slices in vitro are other approaches deserving mention. Several examples were reported. Finally, immortalized and transfected cell lines exhibit a different state of complexity.     

Induction of division and differentiation of somatic embryos in the leaf epidermis of Gaillardia picta

Somatic embroys and subsequent plant regeneration were obtained from isolated leaf epidermis of Gaillardia picta. Abaxial and adaxial epidermal peels (monolayer) from 45 days old aseptic seedlings were isolated and segments measuring 5 mm x 3 mm were cultured on B₅ basal medium supplemented with various growth regulators such as naphthaleneacetic acid or indolebutyric acid and benzylaminopurine or kinetin. Within 12 h of culture the epidermal cells showed receding of cytoplasm from the walls. After 48 h of incubation 3 or 4 localized zones, each consisting of 3–8 cells that accumulated cytoplasm and stained densely, were observed. Mitotic divisions occurred in these zones on day 3 of culture and localized masses of callus were observed in 95% of the cultures after 10 days. In another 5 days, the callus differentiated somatic embryos or roots, depending on the growth regulators and their concentration in the medium.Abbreviations Used BAP 6-benzylamiopurine - IBA indolebutyric acid - Kn kinetin - NAA -naphthaleneacetic acid     

Use of a uterine-cell monolayer culture system for micromanipulated bovine embryos

The objective of this study was to evaluate the growth of micromanipulated bovine embryos in two in vitro culture systems. Sixty ova (day 7 from estrus) were collected in Dulbecco's phosphate-buffered saline (PBS), with 2% fetal calf serum, and transferred to a PBS holding medium containing 10% fetal calf serum to prepare for micromanipulation. Forty embryos (morula to expanded blastocyst stages) were selected for embryo splitting using a modified microsurgery procedure. Thirty-nine of these embryos were successfully bisected into demi-embryos (DE) and the halves allotted by post-manipulation quality grades into one of two treatment groups (Trt). DE in Trt A were cultured in Ham's F-10 medium with 10% FCS (HF-10) while the remaining DE halves from each embryo were cocultured in HF-10 on a monolayer of endometrial fibroblasts (8 x 10(4) viable fibroblast cells plated three days prior to culture) in Trt B. Embryo development, recorded at 12-hour intervals, was evaluated by a split-plot analysis of variance. Results indicated that embryo viability decreased (P<0.001) over time in culture. Overall viability was greater (P<0.001) for DE in Trt B than in Trt A, with a significant (P<0.05) Trt x Time interaction, indicating that embryo viability decreased more rapidly across time in HF-10 than in the monolayer coculture system. The percentage of DE developing at 12, 24, 36, 48, 60 and 72 hours in culture was: 44%, 41%, 33%, 28%, 21% and 18% for Trt A and 69%, 69%, 69%, 67%, 62% and 62% for Trt B. Fourteen of the DE in Trt B attached to fibroblast monolayer and initiated trophoblastic outgrowth and four additional DE remained viable for up to 17.5 days in vitro as intact blastocysts. These findings are the first reported that demonstrate that the zona-free bovine DE will develop during in vitro culture. Also, the bovine endometrial fibroblast monolayer system proved to be excellent for both short term (相似文献   

一种稳定和高产的肝贮脂细胞分离法

改良国外文献方法,用链霉蛋白酶和胶原酶先后原位灌注大鼠肝脏,以11％Metriza-mide密度梯度分离肝贮脂细胞获得成功。贮脂细胞得率为3—4×10~7个/肝脏,存活率在98％以上,纯度达90—95％,传代培养后纯度在98％以上。     

Fish cell culture: A new cell line fromCynoscion nebulosus

Summary A new fibroblast-like cell line, CyN, has been developed from muscle tissue of the marine fishCynoscion nebulosus (the spotted weakfish). A subline, CyN-1, was characterized fully and carried through 100 subcultures. CyN-1 is heteroploid and has a modal chromosome number of 49. The line is susceptible to LT-1, lymphocystis, eastern equine encephalitis and vesicular stomatitis viruses. Optimal growth occurred at 25° to 34° C in growth medium adjusted to 0.150m NaCl. This study was supported in part by the National Oceanographic and Atmospheric Administration, Office of Sea Grant No. 04-3-158-58.