Microdrop Method Research Articles

Tongue squamous cell carcinoma treated by 5-aminolevulinic acid administrated through Microdrop method

BackgroundPostoperative recurrence of tongue squamous cell carcinoma (TSCC) has always been a clinical problem for patients and doctors. Surgery and radiotherapy are the main treatment methods for TSCC, but reoperation often leads to functional impairment. Side effects of radiotherapy include mucosal gland damage, dry mouth, weakened or lost taste. Improved treatment is needed. ObjectiveTo evaluate the clinical outcome of a patient with TSCC treated with Microdrop aminolevulinic acid (ALA) photodynamic treatment (PDT) twice. MethodsALA was dissolved in 5 % lidocaine and the concentration of ALA was 20 % by Microdrop method. Then, the tumor tissue was expanded 1 cm outward, and the injection points were evenly distributed with an upper and lower left and right interval of 2–3 mm. The 1 ml syringe was used to perform the injection in the skin of the tumor area, and there was a small cuticle at each injection point. A pathologically confirmed patient with TSCC received twice Microdrop ALA-PDT treatments, which were evaluated at 1 month and 4 months later. ResultsAfter 3 h of Microdrop ALA injection, the wavelength of semiconductor laser was set to 630 nm, and the energy of 300 mW /cm2 was irradiated for 30 min. After two treatments, the lesions were not visible, and no recurrence occurred after 4 months of follow-up. The patient's tongue function was well preserved and the cosmetic effect was good. ConclusionMicrodrop ALA-PDT may be effective in the salvage treatment of select tongue squamous cell carcinoma.

Quantitatively measuring the cytotoxicity of viscous hydrogels with direct cell sampling in a micro scale format “MicroDrop” and its comparison to CCK8

Tissue engineering holds promise for developing therapeutic applications using viscous materials e.g. hydrogels. However, assessing the cytotoxicity of such materials with conventional assays can be challenging due to non-specific interactions. To address this, we optimized a live/dead staining method for quantitative evaluation and compared it with the conventional CCK8 assay. Our MicroDrop method involved seeding droplets containing 5000 cells in 10 µl medium on 12-well plates. After allowing them to adhere for 4 h, various viscous samples were applied to the cells and measurements were conducted using a fluorescence microscope immediately and at daily intervals up to 72 h. A sodium dodecyl sulfate (SDS) dilution series compared the MicroDrop with the CCK8 assay. The findings revealed a cell-type specific pattern for 10 mg/ml hyaluronic acid (HA), wherein MC3T3-E1 cells maintained 95% viability until 72 h, while L929 cells experienced a gradual decline to 17%. 2 mg/ml HA exhibited consistent viability above 90% across all time points and cell lines. Similarly, fibrin demonstrated 90% viability across dilutions and time points, except for undiluted samples showing a decrease from 85% to 20%. Gelatin-methacrylol sustained viability above 70% across all time points at both 5% and 10% concentrations. The comparison of the SDS dilution series between viability (MicroDrop) and metabolic activity (CCK8) assay showed a correlation coefficient of 0.95. The study validates the feasibility of the established assay, providing researchers with an efficient tool for assessing cytotoxicity in viscous materials. Additionally, it holds the potential to yield more precise data on well-known hydrogels.Graphical

Comparative Study on the Resistance of Beta-Cypermethrin Nanoemulsion and Conventional Emulsion in Blattella germanica.

This study aimed to compare the resistance rates of Blattella germanica to beta-cypermethrin nanoemulsion and conventional emulsion and establish reference values via biochemical detection for conventional emulsion. We conducted experiments using subcultured Blattella germanica and applied the micro-drop method for treatment. Subsequently, the activity of metabolic enzymes was measured using spectrophotometry. Profile analysis was employed to study the resistance rates of beta-cypermethrin nanoemulsion and beta-cypermethrin emulsion. The regression equation for the relationship between generation and resistance factor in Blattella germanica treated with beta-cypermethrin nanoemulsion was as follows: y1 = 0.091x1 + 0.991, with an r-value of 0.990 (F = 95.184, p = 0.01 < 0.05). Similarly, the regression equation for Blattella germanica treated with emulsion was y2 = 0.376x2 + 1.051, with an r-value of 0.993 (F = 141.094, p = 0.007 < 0.05). The comparison of slopes between these two regression equations yielded an F-value of 8.61, indicating a significant difference (p = 0.001 < 0.05). Our findings suggest that the resistance factor in Blattella germanica treated with beta-cypermethrin nanoemulsion differs from that treated with beta-cypermethrin emulsion. Specifically, the resistance factor of beta-cypermethrin nanoemulsion increased at a slower rate compared to beta-cypermethrin emulsion.

Deposition of Gold Nanoparticles on a Self‐Supporting Carbon Foil

AbstractElectron emission cross sections of gold nanoparticles (AuNPs) are important for assessing their radiosensitizing effects from ionizing radiation using Monte Carlo simulations. Measurements of these data require samples of sufficiently large area density, homogeneous nanoparticle distribution, and a mechanically stable sample holder to ensure a low background signal. While several methods exist for the deposition of nanoparticles, there is little information regarding the deposition of AuNPs in an aqueous solution onto a self‐supporting film. The aim of this is to find suitable preparation techniques for AuNP samples which fulfill the above requirements. AuNP samples are produced using different deposition techniques and a 50 nm‐thick carbon foil as the substrate. These samples are characterized with respect to the size and spatial distribution of AuNPs using a scanning electron microscope. The drop‐casting technique yields the best results, while those obtained with the spin‐coater technique are less reproducible regarding sample stability. The microdrop method is deemed unsuitable due to its tendency to form AuNP clusters. Measurements conducted with a synchrotron radiation source, as well as with protons and electrons, confirm the suitability of these samples for studying electron emission spectra of AuNPs for different radiation types.

Antifeeding effects of azadirachtin on the fifth instar Spodoptera litura larvae and the analysis of azadirachtin on target sensilla around mouthparts.

To clarify the types, number, and distribution of sensilla on the head of the fifth instar Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) larvae and identify the main sensilla of azadirachtin acting on larvae, scanning electron microscopy was used to study the morphology of the head and sensilla on the mouthparts. The four sensilla-sensillum basiconicum, sensillum chaeticum, sensillum styloconicum, and sensillum trichodeum-on the head of the fifth instar larvae were treated with 0, 0.1, 0.5, 1, 2, and 4 mg/kg azadirachtin by a microdrop method. The larvae showed an obvious antifeeding effect with azadirachtin. And higher the concentration of azadirachtin, the more obvious the phenomenon of antifeeding activity. The sensillum styloconicum and the sensillum trichodeum were the main sensilla for azadirachtin. When 1 mg/kg azadirachtin was used to treat sensillum styloconicum and sensillum basiconicum, the fifth instar larvae of S. litura showed obvious antifeedant activity and the cumulative feed intake for 24 hr was no more than 30% of the leaf area. Quantitative reverse-transcription polymerase chain reaction verified the expression patterns of some Grs, indicating that Grst43a was upregulated by 1.3- and 3.9-fold, Gor24 was upregulated by 2.5- and 3.3-fold, Gr5a was downregulated by 0.6-fold and upregulated by 2.0-fold, and Gr28a was downregulated by 0.8-fold and upregulated by 3.6-fold upon treatment with 0.5 mg/kg and 1 mg/kg azadirachtin in 24 hr. Gr genes participated in the identification of bitterness and we speculated that Gr genes may indirectly lead to the occurrence of antifeeding behavior.

Faster, cheaper, defined and efficient vitrification for immature porcine oocytes through modification of exposure time, macromolecule source and temperature

Vitrification reduces the developmental competence of porcine immature oocytes. We investigated the effects of modifying various factors on the viability and development of oocytes after vitrification. These factors included: 1) exposure to the vitrification solution, 2) macromolecule addition (bovine serum albumin (BSA) or polyvinyl pyrrolidone (PVP)), 3) treatment with cytochalasin B, 4) equilibration temperature, and 5) vitrification method (microdrop or Cryotop). Oocytes were equilibrated and vitrified using medium containing ethylene glycol and propylene glycol. After warming, oocytes were subjected to in vitro maturation, stimulated parthenogenetically, and cultured in vitro. Survival rate, nuclear maturation, cleavage, development to the blastocyst stage and their quality were compared between the vitrified groups and the non-vitrified control group. It was found that 1) exposure to the vitrification solution for longer than 30 s was detrimental to embryo development; 2) replacement of BSA with PVP improved embryo development; 3) cytochalasin B treatment reduced the survival rates, but did not affect the blastocyst development rates, 4) equilibration at room temperature (25 °C) was the most beneficial, and 5) the microdrop method improved survival rates. With these adjustments, we were able to establish a simplified and defined cryopreservation system for porcine immature oocytes with improved efficacy.

Comparison of the microdrop and minimum volume cooling methods for vitrification of porcine &lt;i&gt;in vitro&lt;/i&gt;-produced zygotes and blastocysts after equilibration in low concentrations of cryoprotectant agents

We compared the efficacy of the microdrop and minimum volume cooling (MVC) methods for the vitrification of in vitro-produced porcine zygotes and blastocysts after equilibration in low concentrations of cryoprotectant agents. Zygotes and blastocysts were equilibrated in 2% (v/v) ethylene glycol and 2% (v/v) propylene glycol for 13–15 min. Then, they were vitrified in a medium comprised of 17.5% ethylene glycol, 17.5% propylene glycol, 0.3 M sucrose, and 50 mg/ml polyvinylpyrrolidone either by either dropping them directly into liquid nitrogen (microdrop method) or placing them on Cryotop sheets in a minimum volume of medium and plunging into liquid nitrogen (MVC method). Both zygotes and blastocysts were successfully vitrified. For the vitrification of zygotes, the MVC and microdrop methods were equally effective; however, for blastocyst vitrification, MVC was superior. For both methods, the vitrification of zygotes produced higher-quality embryos than the vitrification of blastocysts.

Comparison of fertilization outcome between microdrop and open insemination methods in non-male factor IVF patients

Both microdrop and open methods are commonly used for in vitro fertilization (IVF) protocols for embryo culture as well as oocyte insemination. However, few comparative studies evaluating the microdrop or open method of insemination on the fertilization outcome and subsequent embryo development have been performed. A randomized study was conducted to compare microdrop and open fertilization with respect to fertilization rate and embryo development among non-male factor patients undergoing in vitro fertilization and embryo transfer (IVF-ET). The results presented in this study demonstrate that the fertilization failure rate [total fertilization failure rate (TFF) plus low fertilization rate (<25% oocytes fertilized)] in the microdrop insemination group was higher than in the open insemination group (11.9% versus 3.3%, p < 0.001), while the good quality embryo rate and pregnancy rate did not differ significantly between the groups. As a highly complicated process involving many extrinsic and intrinsic factors, further studies are needed to confirm the effects of these insemination methods on the rate of fertilization failure.

English

Mineral oil is usually used to cover the microdrops of medium in oocytes or embryos culture system here designated as oil method. A large number of oocytes are needed for the production of porcine embryos for in vitro fertilization or somatic cell nuclear transfer (SCNT). The oil method not only wastes a lot of mineral oil, but needs tedious steps in the transferring of embryos. Here we designed a new method called nest dish, which need not mineral oil, to replace the oil method and improve the development rates of porcine eggs in vitro. The oocyte maturation rate with the mTCM199 (83.2%) was significantly higher than with the NCSU23 (75.5%, P﹤0.05), although the parthenogenetic cleavage rates with two media were not significantly different (77.7 and 72.4%, P﹤0.05 ). Chosing mTCM199 as base medium, the rate of maturation with concave dish (90.1%) was significantly higher than with the flat dish (82.6%, P﹥0.05) in nest method, although no significant differences in the oocyte maturation were found between flat dish (82.6%) in nest method and oil method (80.0%). Parthenogenetic cleavage from nest method (80.1% for concave dish, 78.0% for flat dish) did not show any decrease compared to oil method (76.2%), but the developmental rate to blastocysts in the nest groups(17.9 and 19.5%) were significantly higher than the oil method (12.3%, P﹤0.05). These results showed that mTCM199 presented higher maturation rate than that NCSU-23 did, and the nest method with concave dish significantly improved the maturation rate of porcine oocytes in vitro and can replace the conventional oil method. &nbsp; Key words:&nbsp;Porcine oocytes,&nbsp;in vitro&nbsp;maturation (IVM), microdrop method, nest dish method.

In vitro development of vitrified buffalo oocytes following parthenogenetic activation and intracytoplasmic sperm injection

The objective of this study was to investigate the potential of swamp buffalo oocytes vitrified-warmed at the metaphase of the second meiotic cell division (M-II) stage to develop to the blastocyst stage after parthenogenetic activation (PA) or intracytoplasmic sperm injection (ICSI). In Experiment 1, we examined the effects of exposure time of oocytes to cryoprotectants (CPA) on their in vitro development after PA. In vitro matured (IVM) oocytes were placed in 10% dimethylsulfoxide (DMSO) + 10% ethylene glycol (EG) for 1 min and then exposed to 20% DMSO + 20% EG + 0.5 M sucrose for 30 s, 45 s or 60 s (1 min + 30 s, 1 min + 45 s and 1 min + 60 s groups, respectively). The oocytes were then exposed to warming solution (TCM199 HEPES + 20% FBS and 0.5M sucrose) for 5 min and then washed in TCM199 HEPES + 20% FBS for 5 min. IVM oocytes without CPA treatments served as a control group. The viability assessed by fluorescein diacetate (FDA) staining was 100% in all groups. The developmental rates after PA to the blastocyst stage between 1min+30s (16%) and control (26%) groups did not differ significantly, but they were significantly higher than those in 1 min + 45 s (10%) and 1 min + 60 s (2%) groups. In Experiment 2, we examined the effect of two CPA exposure times, 1 min + 30 s and 1 min + 45 s on the in vitro development after PA of oocytes vitrified by the microdrop method. The viabilities in vitrified 1 min + 30 s, 1 min + 45 s and the control (without CPA treatments) groups were not different (97%, 95% and 100%, respectively). The development of surviving oocytes to the blastocyst stage in the vitrified 1 min + 30 s group (8%) was significantly higher than that in the vitrified 1 min + 45 s group (4%) and significantly lower than those in control group (26%). In Experiment 3, we examined the effect of two CPA exposure times, 1 min + 30 s and 1 min + 45 s on in vitro development after ICSI of vitrified oocytes. Viabilities in vitrified oocytes among 1 min + 30 s, 1 min + 45 s and control groups were not different (96%, 91% and 100%, respectively). After ICSI, vitrified-warmed oocytes were activated and oocytes with the second polar body were cultured for 7 days. The development of ICSI oocytes to the blastocyst stage in the vitrified 1 min + 30 s group (11%) was significantly higher than that in the vitrified 1 min + 45 s (7%) group and significantly lower than those in control group (23%). In conclusion, our study demonstrated that the 1 min + 30 s CPA treatment regimen could yield the highest blastocyst formation rates after PA and ICSI for oocytes vitrified by the microdrop method.

Generation of Sheffield (Shef) human embryonic stem cell lines using a microdrop culture system

The conventional method for the derivation of human embryonic stem cells (hESCs) involves inner cell mass (ICM) co-culture with a feeder layer of inactivated mouse or human embryonic fibroblasts in an in vitro fertilisation culture dish. Growth factors potentially involved in primary derivation of hESCs may be lost or diluted in such a system. We established a microdrop method which maintained feeder cells and efficiently generated hESCs. Embryos were donated for stem cell research after fully informed patient consent. A feeder cell layer was made by incubating inactivated mouse embryonic fibroblasts (MEFs) feeder cells in a 50 microl drop of medium (DMEM/10% foetal calf serum) under mineral oil in a small tissue culture dish. MEFs formed a confluent layer and medium was replaced with human embryonic stem medium supplemented with 10% Plasmanate (Bayer) and incubated overnight. Cryopreserved embryos were thawed and cultured until the blastocyst stage and the zona pellucida removed with pronase (2 mg/ml; Calbiochem). A zona-free intact blastocyst was placed in the feeder microdrop and monitored for ES derivation with medium changed every 2-3 d. Proliferating hESCs were passaged into other feeder drops and standard feeder preparation by manual dissection until a stable cell line was established. Six hESC lines (Shef 3-8) were derived. From a total of 46 blastocysts (early to expanded), five hESC lines were generated (Shef 3-7). Shef 3-6 were generated on MEFs from 25 blastocysts. Shef7 was generated on human foetal gonadal embryonic fibroblasts from a further 21 blastocysts. From our experience, microdrop technique is more efficient than conventional method for derivation of hESCs and it is much easier to monitor early hESC derivation. The microdrop method lends itself to good manufacturing practice derivation of hESCs.

Poly-β-Hydroxyalkanoate Exert a Protective Effect Against Carbon Starvation and Frozen Conditions in Sphingopyxis chilensis

Several bacterial species have developed physiological response to avoid the cellular damage when are exposed to carbon starvation or frozen stress. For example survival to inanition has been related to endogenous substrates consumptions. The aim of this study was to evaluate if poly-beta-hydroxylkanoates (PHA) consumption enable Sphingopyxis chilensis S37 to survive under carbon starvation or frozen condition. Bacterial cells were grown in R(2)A broth for 48 h, and suspended in mineral saline solutions, without carbon source. The cellular suspension was incubated for 48 or 120 h at 30 degrees C, followed by a frozen period of 48 h at -20 degrees C, and viable bacterial cells were evaluated by the microdrop method. The proportions of cells with PHA were also determined by flow cytometry using Nile Red dye. The results indicate that S. chilensis were able to survive under carbon starvation and frozen conditions. Simultaneously, a decrease in the number of cells containing PHA, and a decrease in the biovolume of the cells (c.a 2.5 times) were also observed under these conditions. The results suggest that consumptions of PHA contributed to the surviving of S. chilensis under frozen stress.

A modified swim-up method reduces polyspermy during in vitro fertilization of porcine oocytes

The general method of porcine in vitro fertilization (IVF), involving the co-culture of both gametes in a medium drop, is thought to be the main reason for the high incidence of polyspermy. The aim of this study was to reduce the polyspermic fertilization of porcine embryos during IVF by the modified swim-up method, based on general sperm swim-up technique. Within this design, a 70 μm pore sized cell strainer was used to separate the sperm pellet placed at the bottom of a tube from the mature oocytes placed within the upper region. The separation of gametes using this permeable barrier was to ensure that only motile sperm gained access to the oocytes. It was found that the rate of polyspermy was significantly lowered for the sperm preparations from three boar breeds in modified swim-up method when compared with that of the general microdrop method ( p < 0.05). However, the penetration rates were found to be similar in both methods for two boar breeds. The average occurrence of blastocysts with more total cell number was higher in the modified swim-up method, while no significant difference in blastocyst rates between the two IVF methods was observed. The frequency of normal diploid embryos was also significantly higher in the modified swim-up method and polyploidy was more frequently observed in microdrop method ( p < 0.05). Our results demonstrated that the modified swim-up IVF method could reduce polyspermic penetration, and consequently produce better quality and karyotypically normal embryos in porcine IVF.

Vitrification of Immature Bovine Oocytes by the Microdrop Method

This study was conducted to determine the optimal vitrification conditions for immature bovine oocytes using the microdrop method. In experiment 1, the optimal pre-equilibration period for microdrop vitrification was examined. The maturation rate of vitrified oocytes with a 3 min first pre-equilibration period (41.1%) was higher than that of vitrified oocytes with a 0 min first pre-equilibration period (21.4%), and the values of those with a 1 (33.9%) or 5 min (27.4%) first pre-equilibration period were intermediate. The value for a 1 min second pre-equilibration period (44.4%) was significantly higher (P<0.05) than those for a 0.5 (28.6%) and 2 min (21.4%) second pre-equilibration period. In experiment 2, the distribution of microtubules in matured oocytes was investigated. There was no difference among the first pre-equilibration times in terms of the rates of normal spindles in vitrified oocytes. However, this value was significantly higher (P<0.05) in the 1 min group (52.8%) compared with the 0.5 (16.7%) and 2 min groups (12.3%). In experiment 3, we investigated the developmental capacity of immature bovine oocytes vitrified under optimal pre-equilibration conditions (3 min and 1 min for the first and second pre-equilibrations, respectively). Although the total fertilization rates were significantly lower (P<0.05) in the vitrified oocytes (65.6%) compared with the control oocytes (92.4%), there was no difference in the rate of normal fertilization (2PN) between the vitrified (78.6%) and control (82.0%) oocytes. Cleavage and blastocyst rates were significantly lower (P<0.05) in vitrified oocytes (55.7 and 2.3%) than in control oocytes (84.4 and 34.7%). Thus, these results indicated that immature bovine oocytes can survive after microdrop vitrification and subsequently can be cultured to mature oocytes capable of undergoing fertilization in vitro and developing into blastocysts.

Development of vitrified–thawed bovine oocytes after in vitro fertilization and somatic cell nuclear transfer

Cryopreservation could be a useful technique for providing a steady source of oocytes for nuclear transfer and in vitro embryo production. The purpose of this study was to develop a method for cryopreservation of bovine oocytes while maintaining the developmental potential following subsequent in vitro fertilization (IVF) or somatic cell nuclear transfer (SCNT). Following vitrification–thawing, the surviving oocytes were (a) used for parthenogenetic activation, (b) examined for pronuclear formation after IVF, (c) examined for embryo development after IVF, and (d) used for SCNT employing fetal fibroblasts transfected with green fluorescent protein (GFP) gene. While most of the oocytes survived vitrification when the microdrop method was used (92.50%), the cleavage and blastocyst formation rates after parthenogenetic activation were lower (46.5% and 11.1%) than that in the non-vitrified control (86.6% and 13.5%). After IVF, the pronuclear formation (2PN) of fertilized embryos was lower in the vitrified group than in the control (21.7% and 59.9%). After SCNT, fusion rates were similar in control (58.33%) and vitrified–thawed oocytes (53.19%). However, the cleavage (73.1% and 46.3%) and blastocyst formation rates (22.2%, 7.4%; p < 0.05) differed between control and vitrified–thawed oocytes. In vitrified–thawed or control oocytes, all embryos reconstructed using fetal fibroblasts transfected with GFP gene showed GFP expression. To evaluate the complete developmental potential, embryos derived from vitrified–thawed and fresh control oocytes were non-surgically transferred to 27 recipients (16 for control and 11 for vitrified–thawed). In the vitrified–thawed group, two pregnancies were detected at day 60, and one of them lasted until day 222. While in the fresh group, one pregnancy maintained to term. In conclusion, vitrified–thawed bovine oocytes could support development into the subsequent stages after IVF and SCNT. In addition, this study showed the possibility of the vitrified–thawed bovine oocytes in the production of transgenic cloned animals. In addition, further studies are required to increase the efficiency of oocyte vitrification for the practical uses and production of live offspring.

Gibberellin-responding and non-responding dwarf mutants in foxtail millet

The sensitivity of foxtail millet (Setaria italica Beauv.) dwarf mutants to GA was studied. Seedlings of dwarf mutants, Aininghuang (ANH) and CH84113 were treated with GAs (GA1, GA4, GA9, GA19 and GA20) using the micro-drop method, or by soaking in GA3 solution. Plants were also sprayed with GA3 solution at the jointing stage. It was found that ANH was a GA-responding dwarf mutant, whose leaf blade, leaf sheath and internode length increased significantly after GA application, whereas CH84113 was a non-GA-responding dwarf mutant. However, the mesocotyl in etiolated seedlings of both ANH and CH84113 responded to exogenous GA3 in a similar way. With the help of an enzyme-linked immunosorbent assay, it was found that the endogenous GA1+3 level in leaves was lower in the GA-responding dwarf mutant ANH, but higher in the non-GA-responding dwarf mutant CH84113, compared with levels in normal cultivars.

Microgotas: Método de inoculación con Rhizoctonia solani Kühn para evaluar genotipos de habichuela (Phaseolus vulgaris L.)

Con el propósito de desarrollar una metodología para inocular habichuela con Rhizoctonia solani se evaluaron los siguientes métodos: masivo, microgotas y discos de 0.5 cm de agar de papa y dextrosa con micelio del hongo. En el método de inoculación con microgotas se examinó la combinación de dilución y volumen de inóculo. El efecto de la edad del inóculo y de la hoja en la expresión de los síntomas también se evaluó. Todas las inoculaciones se realizaron en el haz de la hoja. El método de inoculación más efectivo para la expresión de síntomas fue el de microgotas utilizando la combinación de 10 µl a una dilución de 100 ml de agua destilada esterilizada por plato de Petri (60 mm diam). Los métodos masivo y de discos indujeron síntomas severos con defoliación 72 hrs después de la inoculación. La edad más adecuada de la colonia es de cuatro días. A medida que aumenta la edad del inóculo se reduce el tamaño de la lesión y el éxito de las inoculaciones. La edad de las hojas trifoliadas no influye en la respuesta a la infección. El ensayo de validación demostró el potencial del método para evaluaciones de genotipos de habichuela.

Effects of feeder layer and BRL conditioned medium on mouse embryonic stem cells

In vitro growth and maintenance of embryonic stem (ES) cell lines derived from ICM cells of various blastocysts of 129 strain mice, the sustenance of their pluripotency and normal karyotype depend on the feeder layer of mouse embryonic fibroblasts (MEF). Compared with the feeder layer of MEF cells, medium conditioned by Buffalo rat liver cells (BRL-CM) is able to maintain pluripotency and karyotypic normality of ES cells only in short term cell propagation. Besides, ES cells grown in BRL-CM are also capable of aggregation with 8-cell embryos of Swiss strain and develop into germ line chimaeras. Modification to the method of aggregating ES cells with early embryos by making a hole in agar layer on the top of MEF feeder cells was shown to be more convenient and efficient than the conventional microdrop method.

A highly Sensitive Dwarf Rice Bioassay-&apos;Modified Micro-Drop Method&apos; for Detection of Minute Quantities of Gibberellins

A highly Sensitive Dwarf Rice Bioassay-&apos;Modified Micro-Drop Method&apos; for Detection of Minute Quantities of Gibberellins

ジベレリンの新しいイネ苗テスト &amp;ldquo;点滴法&amp;rdquo; および そのイネ, アサガオ抽出物への適用

ジベレリンの新しいイネ苗テスト &amp;ldquo;点滴法&amp;rdquo; および そのイネ, アサガオ抽出物への適用