Initial Stage Of Cultivation Research Articles

Effect of Various Mentha sp. Extracts on the Growth of Trichoderma viride and Chaetomium globusom on Agar Medium and Pine Wood

This paper presents the effect of water extracts from the leaves of various Mentha spp. on the growth of selected fungi causing the gray decay of wood. The study determined which of the Mentha spp. extracts used had the best effect on inhibiting the development of fungi on various substrates including pine wood. The best results in the complete inhibition of fungi growth on an agar medium were obtained for the M. × piperita ‘Almira’ extract. Biocidal properties were not achieved on wood samples, although it was noticed that at doses of extracts of 600 g/m2 and higher, the growth of fungi in the initial stages of cultivation was clearly inhibited. Chemical substances in the obtained extracts were characterized by gas chromatography. Oxygen monoterpenes were the dominant group of substances, substances belonging to sesquiterpene hydrocarbons, monoterpene hydrocarbons containing oxygen sesquiterpenes, and one substance belonging to non-terpene hydrocarbons were also identified.

Impact of manure compost amendments on NH3 volatilization in rice paddy ecosystems during cultivation

Livestock manure has been widely used in agriculture to improve soil productivity and quality. However, intensive application can significantly enhance soil nitrogen (N) availability and facilitate ammonia (NH3) volatilization during rice cultivation. The effects of different rates of manure application on the NH3 volatilization rate, its mechanism, and their relationships have not been comprehensively investigated. In this study, field trials were conducted to investigate NH3 volatilization in rice paddy soils amended with different livestock manure, cattle manure (CM), and swine manure (SM), at a rate of 0 (NPK), 10, 20, and 40 Mg ha−1 during cultivation. Moreover, the soil physicochemical and biological properties and rice N uptake were investigated. Ultra-fine particulate matter (PM2.5) was measured quantitatively and qualitatively. Manure application significantly increased NH3 emissions compared to the control. Much higher volatilization rates were observed in the SM soils than in the CM soils, even when the same amount of N was applied. This is mainly related to the higher labile NH4+ concentration and urease activity in SM soils. With increasing application levels, NH3 emission rates proportionally increased in the SM, but there was no significant difference in the CM. Livestock manure application significantly increased NH3 volatilization, particularly during the initial manure application and additional fertilization stages during rice cultivation. The results showed that the application of livestock manure significantly increased NH3 volatilization. Moreover, the biochemical properties of manure composts, including labile N and urease activity, mainly affected NH3 dynamics in rice paddies during cultivation rather than their type. Irrespective of manure application, PM2.5, did not show a significant difference at the initial stage of cultivation. NH3 volatilization was not significantly correlated with the formation of PM2.5. It is necessary to develop effective strategies for mitigating NH3 volatilization and maintaining soil quality without decreasing rice productivity in paddy ecosystems.

Contrasting impacts of drying-rewetting cycles on the dissipation of di-(2-ethylhexyl) phthalate in two typical agricultural soils

Di-(2-ethylhexyl) phthalate (DEHP) pollution has become a growing problem in farmlands of China. Drying-rewetting (DW) cycle is one of frequent environmental changes that agricultural production is confronted with, and also a convenient and practical agronomic regulation measure. In this study, in order to explore the effects of DW cycles on the dissipation of DEHP and their driving mechanisms in different types of soils, we performed a 45-day microcosm culture experiment with two typical agricultural soils, Lou soil (LS) and Red soil (RS). High-throughput sequencing was applied to study the response of soil microbial communities in the process of DEHP dissipation under DW cycles. The results showed that the DW cycles considerably inhibited the dissipation of DEHP in LS while promoted that in RS. The DW cycles obviously decreased the diversity, the relative abundance of significantly differential bacteria, and the total abundance of potential degrading bacterial groups in LS, whereas have little effect on bacterial community in RS, except at the initial cultivation stage when the corresponding parameters were promoted. The inhibition of the DW cycles on DEHP dissipation in LS was mainly derived from microbial degradation, but the interplay between microbial functions and soil attributes contributed to the promotion of DEHP dissipation in RS under the DW cycles. This comprehensive understanding of the contrasting impacts and underlying driving mechanisms may provide crucial implications for the prevention and control of DEHP pollution in regional soils.

RUBBER TREE RESPONSE TO N, P and K DOSES IN FERTILIZATION AT PLANTING

The objective of this study was to evaluate the growth, root and shoot dry mass accumulation and nutritional status of rubber tree in the initial stage of cultivation, under different combinations of nitrogen (N), phosphorus (P) and potassium (K). Combinations of the following doses were tested: 0, 20, 40 and 80 kg ha-1 of N; 0, 75, 150 and 300 kg ha-1 of P2O5; and 0, 25, 50 and 100 kg of K2O. Under the soil and climate conditions analyzed, the combinations of NPK fertilization applied at planting only caused significant growth responses of rubber tree plants as a function of the absence of N and its presence at the dose of 80 kg ha-1. Through leaf analysis it was possible to verify that N fertilization and P fertilization are adequately meeting the needs of rubber tree plants, while the K doses tested did not reach the adequate levels of sufficiency.

<i>In situ</i> research of relationship between cellular N/P of dominate algae species and limitation evaluation in Pengxi River of the Three Gorges Reservoir

本文通过选取水华鱼腥藻（Anabaena flos-aquae）、铜绿微囊藻（Microcystis aeruginosa）、空球藻（Eudorina sp.）和湖北小环藻（Cyclotella hubeiana）为三峡库区流域中典型的优势藻，在澎溪河进行原位培养试验，跟踪监测了三峡水库不同运行时期4种典型优势藻细胞氮（Cell-N）、磷（Cell-P）浓度以及环境水体中的总氮（TN）、总磷（TP）浓度，并且结合团队之前的研究成果，根据临界（供应）N/P摩尔比、细胞N/P摩尔比和Guildford的TN/TP摩尔比评价标准对库区水体的营养限制状态进行了评价，为进一步揭示三峡水库运行下支流水域富营养化过程与生理特征的限制性评价提供研究基础.原位试验结果表明：3个评价标准下水体的营养（氮或磷）限制状态基本相同，低水位时期水体无机磷营养盐比较贫乏，在试验初期没有显著的营养盐限制而在末期受到了磷的相对限制；高水位试验初期和末期均未呈现显著的营养盐限制；泄水期营养盐变动频繁，试验初期表现为氮限制而末期表现为磷限制.虽然各藻种在不同时期会表现出不同的营养盐限制性，但总的来看，临界N/P比和细胞N/P比的阈值范围具有一定指示作用，能够从藻类细胞生理的角度对水体的营养状况作出初步评价.;This paper present in situ experiments in Pengxi River of the Three Gorges Reservoir by selecting Anabaena flos-aquae, Microcystis aeruginosa, Eudorina sp. and Cyclotella hubeiana as dominate algae species, monitoring nitrogen (Cell-N) and phosphorus (Cell-P) concentrations of these algae cells in three operating periods, and measuring total nitrogen (TN) together with total phosphorus (TP) concentrations in ambient water body. Combined with our previous findings, the state of nutrient limitation is evaluated via critical (supply) N/P ratio, cellular N/P ratio and Guildford's TN/TP ratio evaluating standard, providing research foundation of limitation evaluation for revealing the eutrophication processes as well as algae physiological characteristics of tributary waters in the Three Gorges Reservoir. The results of in situ research showed that these three evaluation standards presented the same state of nutrient (nitrogen or phosphorus) limitation. Specifically, in low water period, phosphorus was deficient, and no obvious nutrient limitation were presented at initial cultivation stage while phosphorus limitation was appeared at last cultivation stage. In high water period, both initial and last cultivation phase observed no obvious nutrient limitations. In discharge period the initial stage showed nitrogen limitation while the final stage appeared phosphorus limitation because of the frequent change of nutrient. Though each algae in different water periods presented various nutrient limitations, on the whole, the threshold range of critical N/P ratio and cellular N/P ratio have significantly and promisingly indicative effect, the nutrient state of water body can be preliminarily evaluated from the perspective of physiology of algae cells.

Preparation by sol-gel method and evaluation of lanthanum-containing filling glass ionomer cement powder

To improve the mechanical properties of filling glass ionomer cements (GICs), lanthanum substitution for calcium in glass composition was investigated based on formula 2.3SiO2−2.2Al2O3−0.5CaO-0.5CaF2−0.08P2O5 (BF). Compared with the commercial GIC, a series of lanthanum-containing glass powders were prepared via Sol-gel method. Compressive strength and Vickers hardness of experimental GICs were tested. XRD, SEM and EDAX were used to evaluate GIC powders and samples. In vitro biocompatibility was evaluated by methyl-tetrazolium (MTT) assay as well as the net setting time was tested. Incorporation of lanthanum in the glass powder could significantly improve GIC's mechanical properties. The all-lanthanum substitution (1La) GIC showed the highest Compressive strength (146.25MPa), 47.7% and 41.98% higher than commercial and 0La (BF) group, and Vickers hardness (49.25MPa), 39.2% and 28.02% higher (P<0.05), which was possibly due to the new stronger glass network forming, and leading to the improvement of curing reaction.1La and 0La GICs showed fine biocompatibility in initial cultivation stage. The net setting time of experimental GICs met the clinical requirements. The results demonstrated that lanthanum-containing filling GIC powder could be prepared successfully by Sol-gel method as well as could improve the GIC's mechanical strength effectively.

Cultivation of Nannochloropsis sp. using narrow beam angle light emitting diode in an internally illuminated photobioreactor

This paper reports on the growth condition of Nannochloropsis sp. in an annular column-type photobioreactor (PBR) using light-emitting diode as an internal illumination. The microalgae growth in the 20-L batch culture mode under mixed blue (450 nm) and red (660 nm) light-emitting diode (LED) in various conditions such as photoperiod and light intensity (controlled by supplied current) was monitored. Compact-type 5-W LED module with narrow beam angle (radiation pattern) was installed in the PBR so as to obtain higher intensity and deeper penetration to the culture. Based on the PBR dimension with optical path length 120 mm, the minimum light intensity required at the PBR tank inner surface at initial stage of cultivation was approximately 350–370 mol m−2s−1, while mean light intensity derived was 140–160 mol m−2s−1. Photoperiod ratio of light:dark at 18:6 h provided better results compared to 12:12 in terms of final cell density achieved. Efficiency of light utilization was calculated to be 9.0 × 109 cell/mol photon (0.49 g/mol photon), while biomass volumetric productivity was 0.04 g L−1day−1. The usage of narrow beam angle LED was feasible to be used but with further improvement is necessary.

Plant characters of broccoli determinants of head production

ABSTRACT: The increasing consumption of single-head broccoli is due to several factors, among them there are food production in minimally processing form and the existence of hybrids that adapt to various climates, in addition to the simple harvesting of this typical architecture.This study aimed to identify the most relevant plant characters of broccoli, represented by growth characters, which are determinant in the production and canopy area. The study was conducted in an experimental area in Pato Branco city, PR. The 11 characters were evaluated for 365 plants, spaced with 0.8x0.5m, on a blank experiment. The characters of group 1 (height, number of leaves, stem height, stem diameter) were evaluated on the 21 and 58 day after transplanting (DAT), and the leaf area was evaluated on the 17 and 32 DAT. The characters of group 2 were quantity of fresh head mass and canopy area. At the initial stage of cultivation, on the 17 and 21 DAT, variations in the plants characters did not lead toany variation in production. The higher number of leaves and the larger stem diameter on the 58 DAT determined the greater mass of the broccoli heads.

Different Responses of an Invasive Clonal Plant Wedelia trilobata and its Native Congener to Gibberellin: Implications for Biological Invasion.

The invasive clonal plant Wedelia trilobata contains higher levels of ent-kaurane diterpenes, which are precursors of gibberellins (GAs), and higher rates of clonal growth than its native congener W. chinensis in invaded habitats. We hypothesized that the higher levels of endogenous GAs facilitate greater ramet growth in W. trilobata compared with W. chinensis. We quantified endogenous levels of GA1+3 in the two species and compared their growth responses to the changes of endogenous and exogenous GA3 by using short-term and long-term hydroponics experiments. After a period of homogeneous cultivation, levels of endogenous GA1+3 were higher in W. trilobata than in W. chinensis. The reduction of endogenous GAs repressed the emergence of adventitious roots and the growth of W. trilobata in the initial cultivation stage, and inhibited its shoot elongation and biomass. Levels of endogenous GA1+3 were positively correlated with the length of shoots and adventitious roots of W. trilobata. Adventitious roots of W. trilobata also emerged earlier and grew faster when treated with exogenous GA3. In contrast, exogenous GA3 treatment inhibited the length of adventitious roots in W. chinensis, and levels of endogenous GA1+3 did not correlate with shoot or adventitious root length. Our study suggests that GAs accelerate the rapid clonal growth of W. trilobata, more than that of its native congener W. chinensis, illustrating the relationship between plant hormones and the clonal growth of invasive plants. These findings are important for understanding the mechanisms associated with the invasiveness of clonal plants and their potential management.

Differentiation patterns of mouse embryonic stem cells and induced pluripotent stem cells into neurons.

Mouse embryonic stem (ES) cells and induced pluripotent stem (iPS) cells have the ability to differentiate in vitro into various cell lineages including neurons. The differentiation of these cells into neurons has potential applications in regenerative medicine. Previously, we reported that a chick dorsal root ganglion (DRG)-conditioned medium (CM) promoted the differentiation of mouse ES and iPS cells into neurons. Here, we used real-time PCR to investigate the differentiation patterns of ES and iPS cells into neurons when DRG-CM was added. DRG-CM promoted the expression levels of βIII-tubulin gene (a marker of postmitotic neurons) in ES and iPS cells. ES cells differentiated into neurons faster than iPS cells, and the maximum peaks of gene expression involved in motor, sensory, and dopaminergic neurons were different. Rho kinase (ROCK) inhibitors could be very valuable at numerous stages in the production and use of stem cells in basic research and eventual cell-based therapies. Thus, we investigated whether the addition of a ROCK inhibitor Y-27632 and DRG-CM on the basis of the differentiation patterns promotes the neuronal differentiation of ES cells. When the ROCK inhibitor was added to the culture medium at the initial stages of cultivation, it stimulated the neuronal differentiation of ES cells more strongly than that stimulated by DRG-CM. Moreover, the combination of the ROCK inhibitor and DRG-CM promoted the neuronal differentiation of ES cells when the ROCK inhibitor was added to the culture medium at day 3. The ROCK inhibitor may be useful for promoting neuronal differentiation of ES cells.

MODULATION OF FUNCTIONAL MACROPHAGE ACTIVITY BY HLDF6 PEPTIDE UPON ADDING OPIATE RECEPTOR AGONISTS

The effect of a hexamer fragment of the peptide differentiation factor of the HL–60 cell line, HLDF6, on functional activity of C57Bl/6 mouse macrophages upon adding selective agonists of μ–, δ– and κ–type opiate receptors (DAGO, DADLE and Dynorphin (1–13) has been studied in the cell culture. It has been shown that opiate agonists were capable of enhancing adhesive properties and functional activity of macrophages during their direct interaction with cells. The intensity of stimulation depended on the type of the agonist and, respectively, the type of the opiate receptor. HLDF6 peptide enhanced macrophage activity after addition to the culture medium both at the initial cultivation stage and at the moment of phagosytosis induction. The data concerning the combined administration of HLDF6 and opiate agonists suggest the interaction between the peptide and the endogenous opiate system. (Med. Immunol., 2005, vol.7, № 1, pp 77584)

&lt;b&gt;Establishment and content of sugars and phenols in &lt;i&gt;Physalis&lt;/i&gt; callus obtained from different explants and concentrations of bap and naa &lt;/b&gt; - doi: 10.4025/actascibiolsci.v36i1.18074

Obtaining cells of Physalis pubescens is of interest for studies of primary and secondary metabolic pathways, in the search for new active molecules. Our objectives were to evaluate the regeneration potential of explants from different parts of the plant, growth regulators to be used, and the determination of the growth curve of the callus. We used explants of leaf, root, stem and petiole, cultured on Murashige and Skoog medium with different concentrations of 6-benzylaminopurine and a-naphthaleneacetic acid. The explants from stem and petiole had a higher regeneration potential of the shoot to the treatment with 0.5 mg L-1 6-benzylaminopurine, and the explants of leave and root emitted more roots, with lower production of callus. The tests showed that the regeneration of the whole plant should be done in two steps: cultivation for shoot regeneration and transplantation to a new rooting medium. The growth of callus showed five distinct phases, with accumulation of phenols in the final stages of growth. The levels of soluble sugars increased with age, while reducing sugars showed variations, with higher concentrations in the initial stages of cultivation, with fall and rise again at the final evaluation (28th day).

Changes in magnetic properties and their pedogenetic implications for paddy soil chronosequences from different parent materials in south China

SummaryIt remains unknown whether there is a consistent relationship between magnetism dynamics and pedogenesis for paddy soils. In this study, three paddy soil chronosequences, derived from purple sandy shale (PS), Quaternary red clay (RC) and red sandstone (RS) in the hilly regions of south China, were studied to identify changes in magnetism during soil development and to understand their implications for pedogenesis. The results show that magnetic susceptibility (MS) and soft isothermal remanent magnetization (IRMs) simultaneously decreased to extremely small values in the anthrostagnic epipedons during the initial stages of cultivation. In contrast, this decrease was limited in the hydragric horizons of the young paddy soils and even increased in some. These changes suggest that MS and IRMs can be enhanced by the oxidation of Fe2+ in acid paddy soils (between pH 5 and 6) or be depressed by anaerobic transformations of ferrimagnetic minerals. The main influence on magnetic properties was time duration and especially reducing degree of artificial submergence, while parent materials played a supportive role. Magnetic enrichments generally occurred in the clay fraction. Ferrimagnetic clay minerals were more easily altered than minerals in the silt and sand fractions. The study also shows that there was no fixed pattern in the relationship between magnetism and paddy pedogenesis and magnetic properties should be used with care when applying them to environments in which redox processes occur.

Analysis of individual changes in heat resistance of Daphnia magna clones at initial stages of cultivation

We studied 30 daphnia clones with respect to the organism’s heat resistance (HR) at the initial stages of cultivation: ten clones died before the appearance of offspring in F2, while the remaining clones successfully reproduced and produced subsequent generations. Based on changes in F1 of the individual HR level of clones as compared with their ancestors, the conclusion was drawn that there is a disturbance of the work of mechanisms of physiological homeostasis in the population of dead clones. In the remaining clones, there was observed a high negative correlation between the initial individual resistance level and its change in F1 and F2, as well as a sharp narrowing of the variability diapason in F1. In this group of animals, a significant lability of the individual stability level was noted, as well as its ability to regulate the shift of its resistance, which provides a satisfactory work of mechanisms of physiological homeostasis.

Seletividade de herbicidas aplicados em pré-emergência na cultura do algodão

A cultura do algodão tem grande importância econômica e social, visto que é a fibra mais utilizada no setor têxtil. Contudo é uma cultura que apresenta alta sensibilidade a plantas daninhas e há poucos herbicidas seletivos à cultura. Neste contexto o trabalho objetivou avaliar a seletividade de herbicidas aplicados em pré-emergência na cultura do algodão. Os herbicidas alachlor, S-metolachlor, diuron, prometryne, trifluralin e oxyfluorfen foram aplicados isoladamente e em misturas sobre a variedade FMT-701, nas localidades de Diamantino-MT e Campos de Júlio-MT. O delineamento experimental utilizado foi em blocos casualizados com 16 tratamentos e 4 repetições. Para avaliar a seletividade foram realizadas avaliações de altura aos 36; 66 e 150 dias após a aplicação (DAA), fitointoxicação aos 14; 21; 29 e 36 DAA, estande aos 21 e 49 DAA, número de maçãs aos 141 DAA e produtividade do algodão em caroço aos 193 DAA. Os dados foram submetidos à análise conjunta e ao teste de agrupamento Scott-Knott (p>0,05). Os resultados indicaram que alguns tratamentos proporcionaram menor altura de plantas em determinadas avaliações e grande parte dos tratamentos causou injúrias na fase inicial da cultura. Verificou-se que os tratamentos não proporcionaram diferença significativa para as características de estande de plantas, número de maçãs e produtividade de algodão em caroço, comprovando que todos os tratamentos avaliados podem ser utilizados no manejo de plantas daninhas.

Development and dry mass accumulation in callalily at the initial cultivation stage

The cultivation of the calla lily, despite its importance in the floriculture sector, is still limited due to the lack of knowledge of basic production techniques such as development and dry mass accumulation. These techniques facilitate more appropriate management, especially regarding the application of fertilizers, providing better nutrients utilization and greater yields. Thus, this study was aimed at evaluating the growth and development of calla lily plants, establishing growth curves according to dry mass accumulation. Acclimatized and micropropagated calla lily plantlets were grown in plastic pots containing coconut fiber as a substrate and fertilized with a modified formula of Malavolta. Treatments consisted of assessments at intervals of 30 days for 7 months. The design was in randomized blocks with four replications, in a total of 28 plots. Plants were evaluated by observing their growth characteristics and development of shoots, rhizome, roots, as well as production and flower quality. Development of the plants increased throughout the experimental period, with the maximum dry mass accumulation occurring at the end of the experimental period. Blooming was constant with the length of flower stalks increasing with along with the age of the plant.

Quantification of proton budgets in soils of cropland and adjacent forest in Thailand and Indonesia

Continuous cultivation has the potential to accelerate soil acidification. The influence of cultivation on soil acidification was evaluated by calculating proton budget in a soil–vegetation system including solute leaching, vegetation uptake and organic matter decomposition in cropland and adjacent forest in Thailand and Indonesia. In the forests, excess cation accumulation in wood (2.1–3.8 kmolc ha−1 year−1) has contributed to soil acidification at the rate of 0.004 molc for production of 1 mol carbon. In the croplands, soil organic matter loss (2.2–3.9 Mg C ha−1 year−1) has contributed to both proton generation owing to nitrification (1.5–5.0 kmolc ha−1 year−1) and proton consumption owing to mineralization of organic anions (3.6–8.8 kmolc ha−1 year−1) at the rates of 0.008–0.015 and 0.019–0.026 molc for the loss of 1 mol soil organic carbon, respectively. Although the influence of cultivation on proton budget is different depending on the budget of organic matter and soil types (soil pH and texture), cultivation results in soil organic matter loss and soil alkalinization at least during the initial stage of cultivation in tropical regions.

Effect of Poly (Lactic–Co–Glycolic Acid) (75:25)/ Hydroxyapatite Composite on Chondrocyte Culture for Tissue Reconstruction

PLGA (75:25)/hydroxyapatite (HA) composite films were fabricated by solvent-casting method to investigate the effect of various hydroxyapatite content ratio to the PLGA film for cellular attachment and proliferation. Mechanical property of the composite film was characterized by tensile test. The ultimate tensile strength of 10% HA content film was two folds higher than control group. The surface of the film was characterized by contact angle measurement. The PLGA/HA composite film was more hydrophilic than control film. In vitro chondrocyte responses to the composite films were measured by cellular attachment and proliferation test. The attached and proliferated cells were significantly higher on PLGA/HA (10%) composite film than control group (1.44 times higher in attachment test and 1.31 times higher for 6th-day at culture in proliferation assaying, p&lt;0.05). Base on these finding, the PLGA/HA (10%) composite was effective for the cell attachment for the initial stage of cultivation and cell proliferation.

Effects of oxygen partial pressure on cell growth and ginsenoside and polysaccharide production in high density cell cultures of Panax notoginseng

The effects of oxygen partial pressure ( pO 2), within the range 10.6–36.5 kPa, on high density cell cultures of Panax notoginseng were investigated in a bioreactor. A pO 2 of 21.3–29.3 kPa was found optimal for the production of cell mass, ginseng saponin and polysaccharide with corresponding values of 24, 1.75 and 3.0 g l −1 on Day 15, respectively. A low pO 2 was unfavorable to the cell cultures due to oxygen limitation. High pO 2 (36.5 kPa) inhibited cell growth and reduced the production of ginseng saponin and polysaccharide, which was due to the detrimental effect of oxidative burst. The effect of pO 2 on heterogeneity of ginsenosides produced in the cell cultures was also studied. A high pO 2 (at 36.5 kPa) stimulated Rb 1 biosynthesis in the initial stage of cultivation, while a low pO 2 (at 10.6 kPa) inhibited Rg 1 and Rb 1 formation during cultivation.

Orientation Change of Cardiocytes Induced by Cyclic Stretch Stimulation: Time Dependency and Involvement of Protein Kinases

Mechanical stress has been implicated as one of the growth regulators in the heart. We investigated the effect of cyclic stretch stimulation on morphology and orientation of cultured cardiocytes. Embryonic rat (17 days postcoital) cardiomyocytes cultured on silicone dishes were cyclically stretched to 120% in length at a frequency of 30 cycles/min. After 12 h, in the initial stage of cultivation, cardiocytes and intracellular myofibrils oriented parallel to the stretch direction. When the stretch stimulus was prolonged to 24–48 h, myofibrils that oriented perpendicular to the stretch direction emerged. Furthermore, when the cells were stretched only in the later stage (after 24 h of cultivation), both cells and myofibrils tended to orient perpendicular to the stretch direction. Next we examined the effects of chemical compounds on these phase-related changes in myofibril orientation. None of the drugs tested (H-7, HA-1004, staurosporine, herbimycin A, genistein, GdCl3, and EGTA) blocked the parallel orientation of myofibrils induced by the initial-stage stretch. By contrast, H-7, staurosporine, herbimycin A, and genistein did inhibit almost completely the perpendicular orientation of the myofibrils induced by the late-stage stretch, but HA-1004, GdCl3, or EGTA did not. Immunoblotting study using anti-phsophotyrosine antibody indicated that tyrosine phosphorylation of a protein of about 125 kDa was enhanced in a time-dependent manner by the late-stage stretch, but not by the initial-stage stretch. In conclusion: the alignment change induced by cyclic stretch depends on the stage of cultivation: with stretch in the initial stage (within 12 h), cells and myofibrils orient parallel to the stretch; with stretch in the later stage (after 24 h), they orient perpendicular to the stretch. The effect of stretch in the later stage is likely mediated by protein kinase C and tyrosine kinase pathways.