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1. The ferritin heavy chain (FHC) has a vital impact on follicular development in geese, due to its ability to regulate apoptosis of granulosa cells (GCs) and follicular atresia. However, its specific regulatory mechanisms remain unclear. The present study characterised how FHC regulates oxidative stress, cell proliferation and apoptosis in goose GCs by interfering with and overexpressing the FHC gene. 2. After 72 h of interference with FHC expression, the activity of GCs decreased remarkably (p < 0.05), reactive oxygen species (ROS) levels and the expression levels of antioxidant enzyme genes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) increased significantly (p < 0.05). The overexpression of FHC for 72 h was found to significantly reduce the expression of CAT and SOD genes (p < 0.05). 3. Interfering with FHC expression revealed that the expression levels of the cell proliferation gene Aurora kinase A (AURORA-A) were significantly decreased (p < 0.05), while the expression levels of the apoptosis genes B-cell lymphoma-2 (BCL-2) and cysteine aspartate-specific protease 8 (CASPASE 8) increased (p < 0.05). Further research has shown that, when interfering with FHC expression for 72 h, apoptosis rate increased by 1.19-fold (p < 0.05), but the current data showed a lower apoptosis rate after FHC overexpression by 59.41%, 63.39%, and 52.31% at three different treatment times (p < 0.05). 4. In conclusion, FHC improved the antioxidant capacity of GCs, promotes GCs proliferation, and inhibits GCs apoptosis of ovarian follicles in Sichuan white geese. [ABSTRACT FROM AUTHOR]

In a 30 L reactor, acetone (9.5 L) was placed, and B 2 b (1.90 kg, 6.27 mol), B 3 b (1.35 kg, 6.92 mol) and potassium carbonate (1.04 kg, 7.53 mol) were added with stirring. I Bepotastine besilate i ( B 1 b , Figure 1, synonymous with bepotastine besylate), is a non-sedative highly selective histamine receptor antagonist, which has a stabilizing effect on mast cells. According to the literature,[8] B 2 b , B 3 b and potassium carbonate were loaded into acetone at room temperature and then heated to reflux for 7 hours. If dimethylformamide (DMF) or an acetone-water system was used as solvent, the reaction could be complete, but the waste solvent was difficult to recover. [Extracted from the article]

A fiber-reaction zone-matrix three-phase model is developed to evaluate the interfacial fracture toughness of titanium alloys reinforced by SiC monofilaments. Based on fracture mechanics, theoretical equations of GIIc are presented, and the effects of several key factors such as crack length and the interface reaction zone thickness on the critical applied stress necessary for crack growth and interfacial fracture toughness are discussed. Finally, the interfacial fracture toughness of typical composites including Sigma1240/Ti-6Al-4V, SCS-6/Ti-6Al-4V, SCS-6/Timetal 834, SCS-6/Timetal 21s, SCS-6/Ti-24Al-11Nb and SCS-6/Ti-15V-3Cr are predicted by the model. The results show that the model can reliably predict the interfacial fracture toughness of the titanium matrix composites. [ABSTRACT FROM AUTHOR]

We investigated enhancement of articular cartilage regeneration using a combination of human adipose derived stem cells (hADSCs) and TGF-β3 microspheres (MS) in vivo. Poly-lactic-co-glycolic acid (PLGA)MS were prepared using a solid/oil/water emulsion solvent evaporation-extraction method. The morphology of the MS was evaluated by scanning electron microscopy (SEM). The release characteristic of the TGF-β3 MS was evaluated. A New Zealand rabbit model for experimental osteoarthritis (OA) was established using the anterior medial meniscus excision method. Thirty OA rabbits were divided randomly into three groups according to different treatments of the right knee joints on day 7 after surgery: hADSCs/MS group received injection of both hADSCs and TGF-β3 MS; hADSCs group was injected with hADSCs; control group was injected with normal saline. Gross observation, histological staining and RT-PCR for collagen II and aggrecan) were used to assess the severity of OA and for evaluating the effect of combined use of hADSCs and TGF-β3 MS on articular cartilage regeneration in vivo. The MS were spherical with a smooth surface and the average diameter was 28 ± 2.3 µm. The encapsulation efficiency test showed that 73.8 ± 2.9% of TGF-β3 were encapsulated in the MS. The release of TGF- β3 lasted for at least 30 days. At both 6 and 12 weeks after injection, three groups exhibited different degrees of OA. Histological analysis showed that the hADSCs/MS group exhibited less OA than the hADSCs group, and the control group exhibited the most severe OA. Real-time RT-PCR showed that the gene expression of both collagen II and aggrecan were significantly up-regulated in the hADSCs/MS group. At 12 weeks after injection, the hADSCs/MS group also exhibited less OA than the other two groups. Combined use of hADSCs and TGF-β3 MS promoted articular cartilage regeneration in rabbit OA models. [ABSTRACT FROM AUTHOR]

Advanced empirical, and physical-based tyre models have proven to be accurate for simulating tyre dynamics; however, these tyre models typically require expensive and intensive tyre parameterisation. Recent research into wheeled unmanned ground vehicles requiring vertical force analysis has shown good results using a simple linear spring model for the tyre which demonstrate the continued use for simple tyre models; however, parameterisation of the tyre still remains a challenge when load test equipment is not available. This paper presents a cost-effective tyre vertical stiffness parameterisation procedure using only measured tyre geometry and air pressure for applications where high-fidelity tyre models are unnecessary. Vertical forces calculated through an air volume optimisation approach are used to estimate tyre vertical stiffness. Nine tyres from the literature are compared to evaluate the performance of the vertical force estimation and stiffness parameterisation algorithms. Experimental results on a pair of ATV tyres are also presented. [ABSTRACT FROM AUTHOR]

Monodisperse Yttrium-doped BaTiO3(YBT) nanoparticles with good crystallinity and uniform size distribution have been synthesised via a modified sol-hydrothermal method. The solubility of yttrium in BT was no more than 1 mol%. However, at higher Y3+content, excess Y3+were inclined to form Y(OH)3impurities, and after high temperature sintering, impurity YBa3Ti2O8.5can be detected in the ceramics. Further, the variation in the crystal volume indicated that Y3+preferred to substitute for Ti4+as an acceptor. FE-SEM images revealed that the grain size of the ceramics gradually decreased with the raising Y3+concentration. Notably, YBT ceramics with 3 mol% Y3+presented outstanding dielectric-temperature stability, benefitting from the diffuse ferroelectric–paraelectric phase transition and the existence of YBa3Ti2O8.5phases. Stable dielectric-temperature property and low dielectric loss of the YBT ceramics doping with 3 mol% Y3+in the range from 1 kHz to 1 MHz render it as a promising candidate material for high frequency application. [ABSTRACT FROM PUBLISHER]

The formation of macrosegregation driven by multicomponent thermosolutal convection during solidification of WE43 magnesium alloy is numerically studied. A two-dimensional solidification model that describes the conservation of mass, momentum, energy and solute is presented. The experiments are performed in the resin sand mould with a graphite chill placed on one side of the cavity. The validation of computer codes is carried out by comparisons with the experimentally measured cooling curves and concentrations. The influences of mould material and characteristic grain size on macrosegregation are numerically investigated. For a total sand mould casting, the magnitude of macrosegregation is reduced, although the solidification rate is slower than that cooled with a graphite chill. Increasing the characteristic grain size not only causes a serious positive segregation but also leads to the formation of channel segregates. The channel segregation occurs thanks to the weak instabilities of the growing front triggered by the fluid flow. [ABSTRACT FROM PUBLISHER]

The models for single-fiber push out test are developed to evaluate the fracture toughnessGIIcof the fiber/matrix interface in titanium alloys reinforced by SiC monofilaments. The models are based on fracture mechanics, taking into consideration of the free-end surface and Poisson expansion. Theoretical solutions toGIIcare obtained, and the effects of several key factors such as the initial crack length, crack length, friction coefficient, and interfacial frictional shear stress are discussed. The predictions by the models are compared with the previous finite element analysis results for the interfacial toughness of the composites including Sigma1240/Ti-6-4, SCS/Ti-6-4, SCS/Timetal 834, and SCS/Timetal 21s. The results show that the models can reliably predict the interfacial toughness of the titanium matrix composites, in which interfacial debonding usually occurs at the bottom of the samples. [ABSTRACT FROM PUBLISHER]

β-SiC films have been fabricated on (100) Si substrates by laser chemical vapour deposition using hexamethyldisilane ( (CH3)3-Si-Si-(CH3)3) as a source precursor while argon or hydrogen as a diluent gas, respectively. The effects of different diluent gases species on the microstructure and deposition rate have been investigated by varying the flow rate of hexamethyldisilane ( fHMDS). The results showed that pyramid, flower and needle-like morphologies were obtained using argon as diluent gas, whereas only pyramid with little flower structure appeared in the case of hydrogen. The deposition rate ( Rdep) was in proportion to the fHMDS irrespective of diluent gases. Rdep was nearly 50% higher for hydrogen as diluent gas. [ABSTRACT FROM AUTHOR]

Experimental analysis of single-fiber push-out for SiC fiber-reinforced titanium matrix composites (TMCs) is complicated by the incorporation of large thermal residual stresses, strong chemical bond of the fiber/matrix interface and matrix plastic deformation. This paper summarizes the development of push-out test and the characteristics of push-out test for TMCs such as crack initiating at the bottom face and theoretical analysis of the test. Moreover, it deeply analyzes the progresses of interfacial shear strength and fracture toughness, and work focus is pointed out in future. [ABSTRACT FROM AUTHOR]

Compressed sensing (CS) is a topic of great interest in many research fields, especially image processing. However, in the traditional CS framework, one disadvantage is that the computational cost of sparse representation (SR) is too high to meet basic application requirements. Another is that l1-norm minimisation, as the object function of CS recovery, is unsuitable for the approximation of image details. Therefore, this paper presents a novel fractal CS (FCS) framework for digital imaging. The FCS framework is basically as follows: first, the sparse difference (SD) is used to solve the hard problem of sparse representation; then, acquisition of SD is based on the results of classification under a combined fractal and entropy feature space; finally, fractal minimisation is used instead of l1-norm minimisation as the object function to realise high-quality CS recovery of image details. Several experiments show the feasibility and dependability of the FCS imaging framework. [ABSTRACT FROM AUTHOR]

Disconnections in the basal-prismatic (BP) interfaces oftwin have been investigated by many computer simulations. In this paper, we report experimentally that the disconnection in the BP interface oftwin in deformed titanium can be observed by high-resolution TEM (HRTEM). This disconnection can be characterized asusing a coherent dichromatic complex. Correspondingly, the migration process of the basal-prismatic plane resulting fromglide is described. [ABSTRACT FROM PUBLISHER]

Effect of reaction conditions on activity and product distribution on oxygenates formation during Fischer-Tropsch synthesis over a co-precipitated Fe-Cu-K-La/SiO2catalyst was investigated. It showed that alcohols were the main components in total oxygenates. Selectivity of oxygenates decreased with temperature and increased with pressure. Reaction rate and overall oxygenates formation rate generally increased with temperature and pressure. It was found that oxygenates distribution was deeply dependent on reaction conditions. In-situ diffuse reflection infrared Fourier transform spectroscopy results showed that alkyl as well as methoxy species, which were thought to be a C1product precursor, were greatly favored at high temperatures. An enhancement in alcohols and suppression in CO2and CH4with increasing pressure were also observed. Moreover, it was found that carbene was not the rate-controlling step in oxygenates synthesis. [ABSTRACT FROM PUBLISHER]

Ag loaded carbon nanotubes/polyaniline (Ag-GCNT/PANI) composites were prepared by the chemical oxidisation polymerisation, i.e. Ag nano-particles reducted by sodium borohydride in situ were loaded onto CNT dispersed by graphene oxide (GCNT). Then aniline was coated on the surface of Ag loaded GCNT during the in situ polymerisation. The structure and morphology of the composites were characterised by FTIR, XRD, SEM and TEM. The thermoelectric properties of polyaniline composites were also studied. It was found that layered graphene oxide could disperse CNT uniformly. The size of Ag nanoparticles loaded onto the surface of GCNT was about 20-40 nm. Polyaniline was coated evenly on the surface of Ag-GCNT. The thermoelectric power factor of Ag-GCNT/PANI composite reached 3·2×10−7 W m−1 K−2 at 120°C, which was about 71 and 91% higher than that of PANI and GCNT/PANI respectively. [ABSTRACT FROM AUTHOR]

Rootstocks have been used to influence precocity, tree size, fruit quality, yield efficiency, and mineral uptake, and to withstand adverse environmental conditions in many fruit tree species. However, some apple (Malus X domestica Borkh.) rootstocks with excellent horticultural characteristics are difficult to propagate by conventional methods. Tissue culture can be used to propagate new rootstocks developed from breeding programmes for use in experimental trials and for the rapid large-scale production of rootstocks for commercial production. The aim of this study was to propagate several newly-introduced apple rootstocks which were cold-hardy and dwarfing, or semi-dwarfing, and to improve their rooting ability through tissue culture. Major factors that influenced shoot proliferation and rooting were examined and optimal media were developed for the efficient micropropagation and rooting of in vitro shoots of the apple rootstocks 'GM256', 'Budagovsky 71-3-150', and 'Budagovsky 60-160'. The optimum proliferation medium for all three apple rootstocks was Quoirin and Lepoivre (QL) medium containing 0.5 mg 1-11 6-benzylaminopurine (BAP) and 0.05 mg 1-1 indole-3-butyric acid (IBA). Shoot explants of 'Budagovsky 60-160' on 1.0X Murashige and Skoog (MS) proliferation medium, 0.75X MS, or 0.5 X MS showed shoot tip necrosis and hyperhydricity. Rooting percentages and numbers of roots per plantlet were highest using dark culture for all three rootstocks. The highest rooting percentages for all three rootstocks were obtained on 0.5X QL medium containing 0.5 mg 1-1 IBA and 2% (w/v) sucrose, but the rooting percentage of 'Budagovsky 60-160' was not significantly different between 0.25 X MS and 0.5 X QL rooting media. [ABSTRACT FROM AUTHOR]

To recover alumina and silica from alumina rich fly ash, a predesilication process has been developed to extract glassy amorphous silica from the fly ash. The predesilication apparent reaction kinetics in 15 wt-% NaOH solution were studied. The results showed that the predesilication process followed a shrinking unreacted core model of decreasing particle size. The apparent reaction rate of the predesilication process was predominantly controlled by internal diffusion, then by chemical reaction and last by fluid film diffusion. The apparent reaction activation energy for the process was found to be 14·2 kJ mol−1 and the pre-exponential factor was 0·024. Using the leaching process, about 57·56% of glassy amorphous silica was removed from alumina rich fly ash, the silica content being reduced from 40·20 to 26·96% in the resulting dried desilicated fly ash. This study provides a theoretical foundation for the separation of alumina and silica and the design of a predesilication reactor. [ABSTRACT FROM AUTHOR]

This study was conducted to determine if the seasonal succession ofMicrocystisbased on classification using its morphological characteristics was a result of changes in the colonial morphology of the sameMicrocystisspecies. The seasonal variation ofMicrocystiscolonial morphology in Lake Taihu was investigated from June 2011 to November 2011 and found thatM. ichthyoblabe,M. wesenbergiiandM. aeruginosasuccessively dominated in Lake Taihu. Moreover,Microcystiscolonies collected from Lake Taihu were soaked in deionised water in darkness at 4 °C, which resulted in changes in colonial morphology from a morphotype characteristic ofM. ichthyoblabeto those characteristic ofM. wesenbergiiandM. aeruginosa. However, this change was not observed when samples were soaked in raw water from Lake Taihu. The change in morphology was also observed when samples were soaked in cationic solution containing only K, Na, Mg or Fe, but not in 20 mg L−1Ca solution. These results suggest that the seasonal succession ofMicrocystisspecies can be considered a colonial morphological change induced by mucilage solubilisation. [ABSTRACT FROM AUTHOR]

The catalytic oxidation desulfurization system is composed of Na2WO4.2H2O, H2O2, acidic ionic liquid, and phase transfer catalyst has been found suitable for deep removal of organic sulfur in fuels. Under the optimal conditions, the desulfurization efficiency is virtually 100%. Moreover, this acidic ionic liquid can be recycled five times without obviously decrease in activity. Meanwhile, the mechanism of oxidation desulfurization was also elaborated. [ABSTRACT FROM AUTHOR]

An engineered cementitious composite (ECC) is a micromechanically based designed high-performance fiber-reinforced cementitious composite with high ductility and durability, represented by strain-hardening behavior in uniaxial tension. However, the setting time of ECC is retarded and early strength is decreased due to the presence of high volume of fly ash (HVFA). Therefore, shortening the setting time and increasing flexural strength of HVFA-ECC will be of obvious economic importance. The experimental study on setting time and flexural strength of HVFA-ECC proved that the setting time can be shortened by adding alkali accelerator and the optimum content is 4.0%, while the flexural strength of HVFA-ECC can be increased by applying fine particles fly ash, modified fly ash or adding exciting agent of fly ash. [ABSTRACT FROM PUBLISHER]

In the present paper, ZnO nanorod arrays (ZNAs) coating was covered onto wood surface via a hydrothermal method to improve wood flame retardancy. With the scanning electron microscopy, X-ray diffraction and energy disperses X-ray analysis characterisations, a wurtzite structured ZNAs with a length of ∼1·5 μm were densely coated onto the wood surface. Using the cone calorimetry technique, the significant difference in combustion parameters between the untreated and the ZNAs coated wood was observed. In comparison to the untreated wood, the time to ignition was increased about three times, and the burning time of ZNAs coated wood was extended by 55 s. Simultaneously, the heat release rate, total heat release, total smoke production and production of CO, CO2 (COP, CO2P) were significantly reduced. As a result, the thin ZNAs coating could be effectively acted as a protective layer for wood and convert wood from a flammable material into a non-flammable material. [ABSTRACT FROM AUTHOR]

Several letters to the editors are presented including one which discusses a study on the use of problem-based learning (PBL) method to young Chinese medical students, one regarding a study on the competences of physiotherapy students using PBL methodology, and another on the results of an online peer-monitoring research for undergraduate medical students (MS) in Great Britain.

Retrotransposons are the most widespread class of eukaryotic transposable elements and play an important role in genome evolution. Several of these elements have been sequenced and were found to contain different cis-regulatory elements involved in the response to different stress conditions in their long terminal repeat sequences (LTRs). Retrotransposon-based marker systems have proved useful because of their distribution, ubiquity, and prevalence in plant genomes. Here we report on the isolation and characterisation of new RNaseH-LTR sections of the Tyl-copia-like retro-elements in apple DNA. Twenty clones were identified with a variable degree of homology to the Tyl-copia RNaseH gene. Nineteen had the characteristic RNaseH gene, stop codon, polypurine tract (PPT), and putative 3'-LTR sequence elements. The RNaseH sections were aligned using ClustalV to seek potential relationships between sequences. This analysis revealed six distinct Clusters. Conserved motifs, corresponding to cis-regulatory elements, were discovered in the LTRs using plantCARE software and four were characterised. From one putative LTR fragment, we then designed a primer, which, through sequence-specific amplification polymorphism (S-SAP), could distinguish between 'Wellspur Delicious', 'Hardispur Delicious' and 'Starkrimson', and 'Starking' apple, by fingerprinting. The first three varieties originated from 'Starking' through bud mutations. Our results suggest that these bud mutations appeared to have been derived from retrotransposon insertions. [ABSTRACT FROM AUTHOR]

Given the lack of comprehensive research on seed vigour of sweet corn (Zea mays saccharata) and different genetic backgrounds of super sweet and sugar-enhanced sweet corn, it is necessary to improve their seed vigour assessment. Seed vigour status of eight super sweet and eight sugar-enhanced sweet corn hybrids was examined by standard germination, stress resistance, physiological and biochemical tests, and field emergence tests. Analysis of variance showed significant differences between sweet corn genotype and seed vigour. However, vigour assessment was different with different tests. Correlation analysis revealed that volatile aldehyde was the optimal index for seed vigour assessment of super sweet corn and dehydrogenase activity was the optimal for sugar-enhanced sweet corn. On the basis of correlation analysis, regression equations were established for predicting field emergence performance. Verification experimentation suggested the established regression equations were very reliable. [ABSTRACT FROM AUTHOR]

This study assesses the influence of a closed drying environment on kiln brown stain in Pinus radiata sapwood. Three sets of matched timber samples (N = 50) were dried at low temperature (50°C), one without and two with kiln venting. Statistical analysis showed that the closed drying environment produced no significant change in the lightness (L*) of kiln brown stain. Relative to the samples dried in the vented process, there was a small but statistically significant increase in the green color (Δa* ≈ - 1.7) for both the stained area and the unstained early-wood of the samples dried in the non-vented kiln. [ABSTRACT FROM AUTHOR]

Using TGA technology, the volatile matter yields during hydropyrolysis of Chinese Shenmu coal and its derived high purity macerals under different heating rates and pressures were investigated. The Δ W, calculated by the difference between the volatile matter yield of parent coal and that of macerals, is used to evaluate the synergistic effect of macerals during hydropyrolysis. The results showed that with increasing pressure and decreasing heating rate, the Δ W increases. At temperature of 500°C and pressure of 3 MPa, the difference of volatile matter yield between parent coal and vitrinite reaches the maximum and the Δ W also occurs the highest value of 14.1%, suggesting the existence of the synergistic effect between macerals during hydropyrolysis. Based on the structural characteristics of macerals and the basic knowledge of hydropyrolysis, the possible explanation for the synergism are proposed. [ABSTRACT FROM AUTHOR]

We show the application of two recent developments in molecular simulations, density of states (DOS) (Wang–Landau) Monte-Carlo and multiscale modeling, to the understanding of the glass transition. First, we review DOS Monte-Carlo using the two-dimensional Ising model without external field on lattices of varying size. We point out that we can analyze the resulting densities of state in a canonical and a microcanonical way starting from the same simulations. The heat capacity is discussed in both ensembles. Results from both ensembles of off-lattice simulations of a model binary glass former are compared as well. Subsequently, a self-consistent systematic mapping procedure for molecular models from the atomistic to the mesoscale is presented. It allows to efficiently derive mesoscale models with fewer interaction centers from atomistic models preserving the molecular identity. We use the optimization of a corresponding mesoscale model for atactic polystyrene (a good glass former) in the melt as an example. Simulations of different temperatures using this model allow some insight into the glass formation of this system. We point out the strengths and weaknesses of these approaches and give an outlook towards their combination. [ABSTRACT FROM AUTHOR]

A new phenanthraquinone, named bauhinione (1), has been isolated from Bauhinia variegata L., and its structure has been elucidated as 2,7-dimethoxy-3-methyl-9,10-dihydrophenanthrene-1,4-dione on the basis of spectroscopic analysis. [ABSTRACT FROM AUTHOR]

We have previously studied mouse Cdv (carnitine deficiency-associated gene expressed in ventricle)-1 related gene Cdv-1R and its human counterpart CDV-1R, and revealed that mouse Cdv-1R was predominantly expressed in testis by multiple tissue northern analysis. To further localize the Cdv-1R mRNA in mouse testis and epididymis tissue, in situ hybridization study was reported in this article. In the adult mice, the Cdv-1R expression was intensively found in the epithelial cells of the caput and corpus epididymis, whereas it was moderately detected in the initial segment, and weakly in the cauda epididymis. In the seminiferous tubles of the testis, no obvious hybridization signals were observed above the background level. This Cdv-1R region-specific expression pattern in the epididimis suggests Cdv-1R may play an important role in sperm maturation. Moreover, considering the Cdv-1R has a similar expression distribution in epididymis to the OCTN2, it would appear that Cdv-1R might be involved in the carnitine pathway in the epididimis. [ABSTRACT FROM AUTHOR]

The novel electronic, optical and super-conducting properties exhibited by C60 and its assembled materials have greatly stimulated the scientists all over the world racing to study Si60. In this paper we performed an extensive search from eighteen isomers including cages, wires, and stuffed structures of Si. It is found that the fullerene cage is not stable, and the tricapped-trigonal-prism unit is not the structural unit for Si60. While the spherical compact structure is the most stable energetically, in agreement with experiments which suggested a transition from the elongated geometry to a more spherical one for the medium sized Si clusters [J. Chem. Phys. 111 (1999) 7865, J. Chem. Phys. 117 (2002) 3219]. [Copyright &y& Elsevier]

The expression and phosphorylation/dephosphorylation of mitogen-activated protein (MAP) kinases during mouse spermatogenesis and epididymal sperm maturation have been investigated by immunoblotting and immunohistochemical staining with commercially available anti-ERK2 and anti-Active MAPK antibodies. Two forms of MAP kinases, p42ERK2 and p44ERK1, were expressed in a similar amount in spermatogenic cells at different stages. ERK1 and ERK2 were phosphorylated (activated) in early spermatogenic cells from primitive spermatogonia to zygotene primary spermatocytes, while only a small quantity of phosphorylated MAP kinases could be detected in pachytene primary spermatocytes and spermatids. MAP kinase activity in primative spermatogonia and preleptotene primary spermatocytes was the highest among spermatogenic cells. ERK1 and ERK2 were also present in epididymal spermatozoa, and their phosphorylation was increased while spermatozoa pass through epididymis and vas deferens for maturation. It would appear that MAP kinase activation may contribute to the mitotic proliferation of primative spermatogonia, an early phase of spermatogenic meiosis, and, later, sperm motility acquirement. [ABSTRACT FROM AUTHOR]