Bright Granules Research Articles

Pepino mosaic virus antagonizes plant m6A modification by promoting the autophagic degradation of the m6A writer HAKAI

Autophagy plays an active anti-viral role in plants. Increasing evidence suggests that viruses can inhibit or manipulate autophagy, thereby winning the arms race between plants and viruses. Here, we demonstrate that overexpression of an m6A writer from Solanum lycopersicum, SlHAKAI, could negatively regulate pepino mosaic virus (PepMV) infection, inhibit viral RNA and protein accumulations by affecting viral m6A levels in tomato plants and vice versa. The PepMV-encoded RNA-dependent RNA polymerase (RdRP) directly interacts with SlHAKAI and reduces its protein accumulation. The RdRP-mediated decreased protein accumulation of SlHAKAI is sensitive to the autophagy inhibitor 3-methyladenine and is compromised by knocking down a core autophagy gene. Furthermore, PepMV RdRP could interact with an essential autophagy-related protein, SlBeclin1. RdRP, SlHAKAI, and SlBeclin1 interaction complexes form bright granules in the cytoplasm. Silencing of Beclin1 in Nicotiana benthamiana plants abolishes the RdRP-mediated degradation of SlHAKAI, indicating the requirement of Beclin1 in this process. This study uncovers that the PepMV RdRP exploits the autophagy pathway by interacting with SlBeclin1 to promote the autophagic degradation of the SlHAKAI protein, thereby inhibiting the m6A modification-mediated plant defense responses.

Towards the Identification and Classification of Solar Granulation Structures Using Semantic Segmentation

Solar granulation is the visible signature of convective cells at the solar surface. The granulation cellular pattern observed in the continuum intensity images is characterised by diverse structures e.g., bright individual granules of hot rising gas or dark intergranular lanes. Recently, the access to new instrumentation capabilities has given us the possibility to obtain high-resolution images, which have revealed the overwhelming complexity of granulation (e.g., exploding granules and granular lanes). In that sense, any research focused on understanding solar small-scale phenomena on the solar surface is sustained on the effective identification and localization of the different resolved structures. In this work, we present the initial results of a proposed classification model of solar granulation structures based on neural semantic segmentation. We inspect the ability of the U-net architecture, a convolutional neural network initially proposed for biomedical image segmentation, to be applied to the dense segmentation of solar granulation. We use continuum intensity maps of the IMaX instrument onboard the Sunrise I balloon-borne solar observatory and their corresponding segmented maps as a training set. The training data have been labeled using the multiple-level technique (MLT) and also by hand. We performed several tests of the performance and precision of this approach in order to evaluate the versatility of the U-net architecture. We found an appealing potential of the U-net architecture to identify cellular patterns in solar granulation images reaching an average accuracy above 80% in the initial training experiments.

The antiseptic activity of the drug, based on sodium hypochlorite in experimental and spontaneously infected wounds in animals

Sodium hypochlorite is the active ingredient in the antiseptic “Vitosept”. The pharmacological activity of the newly created drug is due to Oxygen, which is released in the active state by the decomposition of unstable hydrochloric acid into hydrochloric acid. A study of the antiseptic effect of the drug Vitosept, conducted on a model of stencil wounds in laboratory rats, found that the speed of healing and reducing the area of skin damage in animals was not inferior to the effectiveness of the comparison drug “Dioxisol-Darnytsia”. According to the obtained results, the latter's use is more appropriate in the first phase of the wound process. In contrast, the use of “Vitosept” in the second and third phases provided acceleration of the formation of mature granulation tissue. In the experimental wounds, proliferative processes were accelerated, and connective tissue was formed with the appearance of a soft scar. The efficacy of Vitosept in the treatment of spontaneously infected wounds has been studied in dogs. For three days from the beginning of treatment in dogs, the general condition improved, body temperature decreased to 38.6 ± 0.3 °C, heart rate was 74 ± 0.6 beats/min, respiratory movements 16 ± 0.4. Positive changes were also observed in the study of wounds. Significant changes in the condition of the injuries were found on the 5th day from the start of treatment. During this period, the general condition of the animals returned to normal, body temperature, heart rate, and respiration was within physiological values. In the dogs of the experimental group, Vitosept showed a slowing of the inflammatory reaction, which was manifested by a decrease in swelling and a reduction in local temperature. The pain was still partially preserved. The amount of purulent exudate decreased significantly. The surfaces of the torn and torn wounds were covered with a small amount of exudate of liquid consistency with detritus impurities, the pH of the wound medium was 6.8 ± 0.1. The surface of the cut wounds was unevenly covered with bright red granulation tissue. At the final stage of healing, both concentric scarring and planar epithelialization were observed. In most cases, in animals of the experimental group, there was concentric scarring, which ended in the formation of a relatively small scar. And only large wounds are healed by planar epithelialization, i.e., the appearance of a wide epithelial rim. In the case of infected wounds in dogs, the drug “Vitosept” compared to animals in the control group normalized morphological and biochemical parameters of blood – erythrocyte count, hemoglobin, blood protein, and its fractions aminotransferase activity in serum. There was a normalization of the values of the leukogram, which indicated the rehabilitation processes in the whole body. As a result of studying the therapeutic efficacy of Vitosept, it was found that its topical application, on average, by 3–4 days accelerated the healing process with the formation of mature granulation tissues and epithelialization in dogs with infected wounds and provided asepsis and normalization of the studied indicators in the recovery process.

Investigations of Sizes and Dynamical Motions of Solar Photospheric Granules by a Novel Granular Segmenting Algorithm

Abstract Granules observed in the solar photosphere are believed to be convective and turbulent, but the physical picture of the granular dynamical process remains unclear. Here we performed an investigation of granular dynamical motions of full length scales based on data obtained by the 1 m New Vacuum Solar Telescope and the 1.6 m Goode Solar Telescope. We developed a new granule segmenting method, which can detect both small faint and large bright granules. A large number of granules were detected, and two critical sizes, 265 and 1420 km, were found to separate the granules into three length ranges. The granules with sizes above 1420 km follow Gaussian distribution, and demonstrate flat in flatness function, which shows that they are non-intermittent and thus are dominated by convective motions. Small granules with sizes between 265 and 1420 km are fitted by a combination of power-law function and Gauss function, and exhibit nonlinearity in flatness function, which reveals that they are in the mixing motions of convection and turbulence. Mini granules with sizes below 265 km follow the power-law distribution and demonstrate linearity in flatness function, indicating that they are intermittent and strongly turbulent. These results suggest that a cascade process occurs: large granules break down due to convective instability, which transports energy into small ones; then turbulence is induced and grows, which competes with convection and further causes the small granules to continuously split. Eventually, the motions in even smaller scales enter in a turbulence-dominated regime.

Evolution of exploding granules from coordinated observations by THEMIS, IRIS, SDO/HMI, and HINODE, and a simulation

Exploding granules constitute the strongest horizontal flows on the quiet Sun and contribute to the structure of the surface horizontal velocity fields which build the large-scale organization of the discrete magnetic field. In this work we explore exploding granule expansion through the observations of the ground-based THEMIS telescope, IRIS, SDO, and the Hinode space-borne instruments, and finally with the magnetohydrodynamics simulation. We evaluate the detection and the expansion of exploding granules at several wavelengths and at various spatial and temporal resolutions. To analyze the different temporal sequences, two methods of image segmentation are applied to select the granules. The first allows us to follow individually the exploding granules observed simultaneously by THEMIS, IRIS, and SDO. The second uses long time independent sequences from THEMIS, IRIS, SDO, Hinode, and a simulation. In the first method (called manual) the segmentation isolates the cell of the granules (bright granules and intergranular parts), while in the second method (called statistical) only the bright part of the granules are isolated. The results obtained with simultaneous or distinct temporal observations using the two methods of segmentation are in good agreement. The granule area evolves linearly with an expansion velocity that decreases with the radius. A rapid decrease in the velocity expansion in the first two minutes is observed. The detection and measurement of the dynamics of the explosive granules can be performed from ground- and space-based instruments. Our work reveals the usefulness of SDO data, with low spatial resolution, to study the dynamics of the exploding granules all over the solar surface.

Height-dependent Velocity Structure of Photospheric Convection in Granules and Intergranular Lanes with Hinode/SOT

Abstract The solar photosphere is the visible surface of the Sun, where many bright granules, surrounded by narrow dark intergranular lanes, are observed everywhere. The granular pattern is a manifestation of convective motion at the photospheric level, but its velocity structure in the height direction is poorly understood observationally. Applying bisector analysis to a photospheric spectral line recorded by the Hinode Solar Optical Telescope, we derived the velocity structure of the convective motion in granular regions and intergranular lanes separately. The amplitude of motion of the convective material decreases from 0.65 to 0.40 km s−1 as the material rises in granules, whereas the amplitude of motion increases from 0.30 to 0.50 km s−1 as it descends in intergranular lanes. These values are significantly larger than those obtained in previous studies using bisector analysis. The acceleration of descending materials with depth is not predicted from the convectively stable condition in a stratified atmosphere. Such convective instability can be developed more efficiently by radiative cooling and/or a gas pressure gradient, which can control the dynamical behavior of convective material in intergranular lanes. Our analysis demonstrated that bisector analysis is a useful method for investigating the long-term dynamic behavior of convective material when a large number of pixels is available. In addition, one example is the temporal evolution of granular fragmentation, in which downflowing material develops gradually from a higher layer downward.

C4-P-10Three-dimensional ultrastructural analysis of secretory granules in histological paraffin sections of endocrine tumors using low-vacuum SEM

Secretory granules of endocrine tumors are traditionally identified by transmission electron microscopy of tissue samples. Recently, we developed a simple method for three-dimensional morphological analysis of conventional paraffin sections using low-vacuum scanning electron microscopy (SEM) [1], and showed that this technique was useful for pathological diagnosis of renal biopsy samples [2]. In this study, we investigated whether this method is useful as an adjunct in pathological diagnosis of endocrine tumors. Preparations were processed according to our original method. Paraffin sections (5 μm thick) obtained from a normal rat pancreas as a control, a human pituitary adenoma and a colorectal carcinoid tumor were generated by the conventional method. After deparaffinization, the sections were stained only with platinum blue aqueous solution (TI-blue staining kit: Nisshin EM, Tokyo) for 15 min at room temperature, and then observed by low-vacuum SEM (TM-1000, TM3030 plus: Hitachi, Tokyo) at high magnification (~30,000×). Under low-vacuum SEM, secretory granules of each cell could be identified as bright spherical granules in each paraffin-sectioned tissue, depending on the contrast of BSE signals. Figure shows low-vacuum SEM image (a) and TEM image (b) of endocrine secretory granules 100–260nm in diameter (arrows) in colorectal carcinoid tumor cells. Our results suggest that low-vacuum SEM of conventional paraffin sections is suitable for the pathological diagnosis of endocrine tumors. [1] Inaga et al., Arch. Histol. Cytol., 72 (2009) 101-106. [2] Okada et al., Biomed. Res., 35 (2014) 345-350. C4-P-09 doi:10.1093/jmicro/dfv327

Chlorellosis: An emerging algal disease of Animals and Humans

Chlorellosis, an emerging opportunistic algal disease, is reported from Australia, Brazil, India, Mexico, Sudan and USA. The disease is caused by Chlorella, a ubiquitous alga, which has been recovered from diverse natural substrates including water. Sporadic cases of cutaneous and systemic chlorellosis are recorded in humans and many species of animals. Most cases in cattle are accidentally detected during meat inspection in abattoirs. The incidence of disease is usually high in areas of wetlands with poor sanitation. The source of infection is exogenous and immunosuppression, skin trauma and heavy environmental exposure are considered as the predisposing factors. The exact mode of transmission is not yet clearly established. Disseminated disease occurs in severely immunocompromised individuals. Microscopic examination of wet mounts of wound exudates or touch smears from infected tissues may help to observe bright green pigment granules of Chlorella. However, transmission electron microscopy can support the diagnosis of disease. Currently, molecular tools have been applied to confirm Chlorella infection. The surgical excision of affected part remains the only choice of disease management. Removal of animals from the affected area, avoiding barbed wire injury, algicidal treatment of water and immediate attention to superficial wound may be effective strategies to control chlorellosis. Further studies on the ecology, pathogenesis, diagnosis, epidemiology, and chemotherapy are needed to get a better insight of this unusual emerging pseudofungal disease. It is recommended that the efficacy of “PHOL” and “Narayan” stain to undertake the detailed microscopic morphology of Chlorella isolates and Pal sunflower seed medium for the isolation of Chlorella from clinical and environmental material should be investigated.

Macular Corneal Dystrophy: In Vivo Confocal and Structural Data

To demonstrate the corneal morphologic aspects obtained with invivo confocal microscopy (CM) and light and electron microscopy of specimens obtained from the same patients with macular corneal dystrophy (MCD). Case series. Five consecutive patients affected by MCD undergoing penetrating keratoplasty (PK) in 1 eye. The patients were examined with the slit-lamp, optical pachymetry, and CM before undergoing PK. The corneal buttons were processed for light, transmission, and scanning electron microscopy. Corneal invivo CM, corneal light, and electron microscopy. Confocal microscopy showed areas of altered reflectivity in basal epithelial cells, which appeared hyperreflective or completely white. In the anterior stroma, rectilinear hyperreflective areas were shown. The stroma was characterized by a granular appearance of both keratocytes and extracellular matrix. Dark striae of different length and orientation were present in the middle and posterior stroma. The corneal endothelium showed polymegethism and cells containing bright granules in their cytoplasm. The histopathologic study demonstrated areas of thickened Bowman's layer covered by an epithelium reduced in height. The Bowman's layer thickenings were due to the accumulation of free or vesiculated material of different electron density. The keratocytes showed intracytoplasmatic vesicles, whereas the extracellular matrix presented a large quantity of intercellular electron-lucent material and parallel lamellae with an undulated course. Occasional macrophages, filled with vesicles of granular-filamentous material and evident podosomes, were observed. Descemet's membrane was formed by a normal anterior banded zone and a posterior nonbanded zone of honeycombed aspect. The endothelial cells showed a large number of intracytoplasmic vesicles. The structural changes observed with the histopathologic methods give an account and provide an explanation for the pathologic changes demonstrated by CM in the course of MCD. This may contribute to the understanding of invivo imaging, allowing a better, noninvasive study of the disease evolution.

Surface characteristics of mussel-inspired polydopamine coating on titanium substrates

Mussel adhesive proteins are non-toxic, biodegradable and have low immunogenic qualities that make them highly attractive for medical purposes compared with man-made materials. 3,4-DOPA, which is a dopamine precursor, is a critical element for achieving mussel-like adhesive properties. In present study, polydopamine was coated onto the titanium surfaces by dipping in a 2 mg/mL dopamine solution in 10 mM Tris-HCl buffer at pH 8.5. EDX element analysis and Raman spectroscopic analysis of the surface were conducted to verify the formation of polydopamine. The surface characteristics of polydopamine-coated titanium plates were observed by SEM and AFM. Hydrophilicity and corrosion-resistance were also evaluated by static contact angle measurements and potentiodynamic polarization corrosion tests. The absorption intensity for pH-induced polymerization rapidly increased for the initial four hours and thereafter smoothly increased. EDX element analyses revealed that the content of carbon and oxygen increased and the content of titanium decreased after the coating process. In the Raman spectra, polydopamine resulted in two new peaks at approximately 1 370 and 1 570 cm−1 resulting from the stretching and deformation of catechol. Microstructural features revealed that nanometer-sized bright granules were randomly distributed after coating, and these nanoparticles grew with increased coating time. The Ra values of polydopamine-coated titanium plates were showed to increase with coating time. Compared to the pure titanium curve, the inflection point of polydopamine-coated titanium was located at a higher corrosion potential and lower corrosion current density. Findings from our research suggested that polydopamine coatings offer a versatile approach for titanium surface modification.

The statistical distribution of the magnetic-field strength in G-band bright points

G-band bright points are small-sized features characterized by high photometric contrast. Theoretical investigations indicate that these features have associated magnetic field strengths between 1-2 kG. Results from observations instead lead to contradictory results, indicating magnetic fields of only kG strength in some and including hG strengths in others. In order to understand the differences between measurements reported in the literature, and to reconcile them with results from theory, we analyze the distribution of magnetic field strength of G-band bright features identified on synthetic images of the solar photosphere, and its sensitivity to observational and methodological effects. We investigate the dependence of magnetic field strength distributions of G-band bright points identified in 3D magnetohydrodynamic simulations on feature selection method, data sampling, alignment and spatial resolution. The distribution of magnetic field strength of G-band bright features shows two peaks, one at about 1.5 kG and one below 1 hG. The former corresponds to magnetic features,the second mostly to bright granules. Peaks at several hG are obtained only on spatially degraded or misalligned data. Simulations show that magnetic G-band bright points have typically associated field strengths of few kG. Field strengths in the hG range can result from observational effects, thus explaining the discrepancies presented in the literature. Our results also indicate that outcomes from spectro-polarimetric inversions with imposed unit filling-factor should be employed with great caution.

Distribution of magnetic fields in the quiet Sun

Context. The distribution of magnetic fields in the atmosphere of the quiet Sun has been extensively studied with various methods, but it is still a matter of debate. Previous analyses mostly rely on the inversion of spectro-polarimetric data and different methods lead to somewhat different results. Aims. Here we do not intend to determine the magnetic field vector, but we use total polarization images as tracers of the magnetic field distribution and we study their cross-correlations with granulation and reversed-granulation images. Methods. We used high-resolution spectro-polarimetric scans obtained in the 630 nm FeI line pair at varying heliocentric angles along the north-south polar axis of the Sun, with the Solar Optical Telescope (SOT) onboard Hinode. We obtain polarization images by summing the total polarization (linear and circular) in each line. We compute the 2D correlation of polarization images and their cross-correlations with images of the granulation observed simultaneously in the line wings and with the reversed granulation observed in the line cores, and we examine their center-to-limb variations. Results. The correlation-widths of polarization images have on the average, the same value (1.3 �� ) as the correlation-width of the granulation, showing that the granular scale is a characteristic scale of the quiet Sun magnetic field distribution. At disk center the cross-correlation between total polarization and the granulation shows a negative peak. Out of disk-center both a negative and a positive peak are detected. The cross-correlation of polarization images with the reversed granulation always shows a positive peak. We assign these cross-correlation signals to the presence of two kinds of magnetized regions spatially separated, one of them is located in the intergranular lanes (anti-correlated with the granulation), the other one lies within the bright granules. For images obtained out of disk center, the correlation and anti-correlation peaks are shifted along the north-south direction and the shifts measured at the same limb-distance in the southern and northern hemispheres have opposite values. A consistent interpretation of these shifts is proposed in terms of a perspective effect arising when two images formed at different heights are observed at an angle. We were able to measure the perspective effect for the magnetic component correlated with the reversed granulation. Its polarization signals observed in the FeI 630.25 nm line and in the 630.15 nm line, are formed respectively 100 km and 150 km below the bright features seen at line centers.

Ependymosarcoma with eosinophilic granular cells

Ependymosarcoma is a new entity of malignant gliomas composed of ependymal and sarcomatous components. Were port a rare case of ependymosarcoma with eosinophlic cells which occurred to the right trigon of the lateral ventricle.A 62-year-old man complained of headaches over a 2-month period. A hard, gray mass was found in the right trigon of the lateral ventricle during the operation.Although he received radiation and chemotherapy, the patient died due to tumor disseminating through the whole brain within 7 months after the operation. The histological examination revealed that the anaplastic glial components intermingled with the sarcomatous components. Immunohistochemically, sarcomatous cells were positive for α smooth muscle actin and desmin. However, anaplasticglial cells were not positive for these markers. In addition, Masson trichrome stain showed a plethora of collagen fibers between sarcomatous cells, but no collagen fibers were produced by the glial tumor cells. Solid focal papillary lesions of the glial tumor showed dot-like epithelial membrane antigen and diffuse cytoplasmic D2-40 immunoreactivity. Based on the above findings, these anaplastic glial tumor cells should show focal ependymal differentiation, and sarcomatous cells show myofibroblastic differentiation. In addition, almost 10%of the tumor cells in the neoplasm showed bright eosinophilic granules in the cytoplasm. These cytoplasmic eosinophilic granules and bundles were negative on PAS staining. Intracytoplasmic eosinophilic granules of tumor cells were strongly positive for αB-crystallin, HSP 27 and GFAP, respectively. These findings suggest that the clinicopathological characteristics of the present case should be consistent with the criterion of ependymosarcoma by Rodriguez et al.

Quiet Sun magnetic fields observed by Hinode: Support for a local dynamo

The Hinode mission has revealed copious amounts of horizontal flux covering the quiet Sun. Local dynamo action has been proposed to explain the presence of this flux. We sought to test whether the quiet Sun flux detected by Hinode is due to a local or the global dynamo by studying long-term variations in the polarisation signals detectable at the disc centre of the quiet Sun between November 2006 and May 2012, with particular emphasis on weak signals in the internetwork. The investigation focusses on line-integrated circular polarisation V_tot and linear polarisation LP_tot profiles obtained from the Fe I 6302.5 \AA absorption line in Hinode SOT/SP. Both circular and linear polarisation signals show no overall variation in the fraction of selected pixels from 2006 until 2012. There is also no variation in the magnetic flux in this interval of time. The probability density functions (PDF) of the line-of-sight magnetic flux can be fitted with a power law from 1.17 x 10^17 Mx to 8.53 x 10^18 Mx with index \alpha=-1.82 \pm 0.02 in 2007. The variation of \alpha 's across all years does not exceed a significance of 1\sigma. Linearly polarised features are also fitted with a power law, with index \alpha=-2.60 \pm 0.06 in 2007. Indices derived from linear polarisation PDFs of other years also show no significant variation. Our results show that the ubiquitous horizontal polarisation on the edges of bright granules seen by Hinode are invariant during the minimum of cycle 23. This supports the notion that the weak circular and linear polarisation is primarily caused by an independent local dynamo.

Nuclear matrix proteins (with molecular masses of 38 and 50 kDa) are transported by chromosomes in mitosis

Using the immunofluorescence method, sera M-68 and K-43 from patients with autoimmune diseases were shown to stain interphase nuclei and the periphery of mitotic chromosomes of pig embryo kidney cells. Western blotting revealed a polypeptide with a molecular mass of 50 kDa in M-68 serum and polypeptide with a molecular mass 38 kDa in K-43 serum. In the nuclear protein matrix, the antibodies to protein with a molecular mass of 38 kDa stained only the nucleolar periphery, while the antibodies to protein with a molecular mass of 50 kDa stained not only the nucleolar periphery, but also all interphase nuclei. It was shown that, among all components of the nuclear protein matrix (lamina, internuclear network, residual nucleoli), only the nucleolar periphery contained the 38-kDa protein, while the 50-kDa protein was part of the residual nucleolar periphery and participated in the formation of a nuclear-protein network. Both proteins in interphase cell in situ were located in nuclei, but one of them with a molecular mass of 50 kDa was in the form of small, clearly outlined granules, while the other protein (38 kDa) was in the form of small, bright granules on a background of a diffusely stained nucleus. Both proteins also were revealed as a continuous rim around the nucleolar periphery. During all mitotic stages, the 50-kDa protein was seen over the whole chromosomal periphery as a sheath, while the 38-kDa protein formed individual fragments and granules around them. After the decondensation of the nucleus and chromosomes induced by hypotonic treatment, both antibodies stained interphase nuclei diffusely, whereas, in mitotic cells, they stained the surfaces of swollen chromosomes. Polypeptide with a molecular mass of 50 kDa maintained a strong connection with the periphery of the chromosome in the norm during decondensation induced by hypotonic treatment and during subsequent recondensation in isotonic medium, while, during recondensation, protein with a molecular mass of 38 kDa partially lost contact with the chromosome and, at the same time, appeared in the form of granules in the cytoplasm. The obtained data allow one to conclude that nuclear matrix proteins can be transferred with peripheral chromosomal material; similar to the main nucleolar proteins (fibrillarin, B-23, nucleolin, et al.) and some non-nucleolar components of the nuclear protein matrix, they can also have connections of different stabilities with chromosomal periphery.

DETECTION OF SUPERSONIC HORIZONTAL FLOWS IN THE SOLAR GRANULATION

Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering ~3%-4% of the solar surface at any time, but these flows have not been detected unambiguously as yet. Using data from the spectropolarimeter aboard the Hinode satellite, I present direct evidence of fast horizontal plasma motions in quiet-Sun granules. Their visibility increases toward the limb due to more favorable viewing conditions. At the resolution of Hinode, the horizontal flows give rise to asymmetric intensity profiles with very inclined blue wings and even line satellites located blueward of the main absorption feature. Doppler shifts of up to 9 km s–1 are observed at the edges of bright granules, demonstrating that the flows reach supersonic speeds. The strongest velocities occur in patches of 05 or less. They tend to be associated with enhanced continuum intensities, line widths, and equivalent widths, but large values of these parameters do not necessarily imply the existence of supersonic flows. Time series of spectropolarimetric measurements in regions away from the disk center show the transient nature of the strong horizontal motions, which last only for a fraction of the granule lifetime. Supersonic flows are expected to produce shocks at the boundaries between granules and intergranular lanes, and may also play a role in the emergence of small-scale magnetic fields in quiet-Sun internetwork regions.

The Horizontal Magnetic Flux of the Quiet‐Sun Internetwork as Observed with theHinodeSpectro‐Polarimeter

Observations of very quiet Sun using the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard the Hinode spacecraft reveal that the quiet internetwork regions are pervaded by horizontal magnetic flux. The spatial average horizontal apparent flux density derived from wavelength-integrated measures of Zeeman-induced linear polarization is -->BTapp = 55 Mx cm −2, as compared to the corresponding average vertical apparent flux density of -->| BLapp| = 11 Mx cm −2. Distributions of apparent flux density are presented. Magnetic fields are organized on mesogranular scales, with both horizontal and vertical fields showing voids of reduced flux density of a few granules spatial extent. The vertical fields are concentrated in the intergranular lanes, whereas the stronger horizontal fields are somewhat separated spatially from the vertical fields and occur most commonly at the edges of the bright granules. High-S/N observations from disk center to the limb help to constrain possible causes of the apparent imbalance between -->| BLapp| and -->BTapp, with unresolved structures of linear dimension on the surface smaller by at least a factor of 2 relative to the SOT/SP angular resolution being one likely cause of this discrepancy. Other scenarios for explaining this imbalance are discussed. The horizontal fields are likely the source of the seething fields of the quiet Sun discovered by Harvey et al. The horizontal fields may also contribute to the hidden turbulent flux suggested by studies involving Hanle effect depolarization of scattered radiation.

Hinode Observations of Horizontal Quiet Sun Magnetic Flux and the “Hidden Turbulent Magnetic Flux”

We present observations of magnetic fields of the very quiet Sun near disk center using the Spectro-Polarimeter of the Solar Optical Telescope aboard the Hinode satellite. These observations reveal for the first time the ubiquitous presence of horizontal magnetic fields in the internetwork regions. The horizontal fields are spatially distinct from the vertical fields, demonstrating that they are not arising mainly from buffeting of vertical flux tubes by the granular convection. The horizontal component has an average “apparent flux density” of 55 Mxcm$^{-2}$ (assuming the horizontal field structures are spatially resolved), in contrast to the average apparent vertical flux density of 11 Mxcm$^{-2}$. The vertical fields reside mainly in the intergranular lanes, whereas the horizontal fields occur mainly over the bright granules, with a preference to be near the outside edge of the bright granules. The large apparent imbalance of vertical and horizontal flux densities is discussed, and several scenarios are presented to explain this imbalance.

Two trichodinid ectoparasites from marine molluscs in the Yellow Sea, off China, with the description of Trichodina caecellae n. sp. (Protozoa: Ciliophora: Peritrichia)

The morphology and infraciliature of two ectoparasitic ciliates, Trichodina caecellae n. sp. and T. ruditapicis Xu, Song & Warren, 2000, parasitising the gills of marine molluscs from the Shandong coast of the Yellow Sea, China, were investigated following wet silver nitrate and protargol impregnation. T. caecellae was found on the small marine sand clam Caecella chinensis Deshayes and is distinguished mainly by the acute triangle-like blade, the very delicate central part and the needle-shaped ray. T. ruditapicis was studied based on four populations from three clams: two populations from Ruditapes philippinarum (Adams) and one each from Saxidomus purpuratus (Sowerby) and Solen grandis Dunker. All four populations fell within the range of morphometry and agreed closely in the overall appearance of the adhesive disc. However, variability was found in the denticle structure, especially in populations from different host clams. Our observations suggest that denticle morphology may be more or less variable between and within populations, and that such minor differences should not be overestimated. It should be emphasised that, except for the denticle morphology, the bright granules or circles in the centre of the adhesive disc represent another important feature facilitating the identification of this trichodinid species.

Calmodulin concentrates at the apex of growing hyphae and localizes to the Spitzenkörper in Aspergillus nidulans

The calmodulin (CaM) localization pattern in the growing hyphal tip of Aspergillus nidulans was studied with the functional GFP::CaM fusion protein. A faint tip-high gradient of CaM was found in the growing hyphal tip, with CaM highly localized in the region corresponding to the Spitzenkörper forming a bright granule. The position of highly concentrated CaM in the extreme apex seemed to determine the orientation of the hypha. The normal pattern of CaM localization was also shown to be dependent on the integrated actin cytoskeleton. When the growth of the hyphal tip ceased, CaM failed to localize in the bright granule and was evenly distributed in the hyphal tip. These findings suggest that CaM may play an important role in establishing and maintaining apical organization, morphogenesis, and growth in Aspergillus nidulans.