Normal Growth Rate Research Articles

Roles of EDTA washing and Ca2+ regulation on the restoration of anammox granules inhibited by copper(II)

We investigated the feasibility of using ethylene diamine tetraacetic acid (EDTA) washing followed by Ca2+ enhancement for the recovery of anammox reactors inhibited by Cu(II). Kinetic experiments and batch activity assays were employed to determine the optimal concentration of EDTA and washing time; and the performance and physiological dynamics were tracked by continuous-flow monitoring to evaluate the long-term effects. The two-step desorption process revealed that the Cu in anammox granules was primarily introduced via adsorption (approximately, 80.5%), and the portion of Cu in the dispersible layer was predominant (accounting for 71.1%). Afterwards, the Cu internalized in the cells (approximately, 14.7%) could diffuse out of the cells and be gradually washed out of the reactor over the next 20 days. The Ca2+ addition that followed led to an accelerated nitrogen removal rate recovery slope (0.1491kgNm−3d−2) and a normal biomass growth rate (0.054d−1). The nitrogen removal rate returned to normal levels within 90 days and gradual improvements in granular characteristics were also achieved. Therefore, this study provides a new insight that externally removing the adsorbed heavy metals followed by internally repairing the metabolic system may represent an optimal restoration strategy for anammox consortium damaged by heavy metals.

Correction of the equilibrium temperature caused by slight evaporation of water in protein crystal growth cells during long-term space experiments at International Space Station.

The normal growth rates of the {110} faces of tetragonal hen egg-white lysozyme crystals, R, were measured as a function of the supersaturation σ parameter using a reflection type interferometer under μG at the International Space Station (NanoStep Project). Since water slightly evaporated from in situ observation cells during a long-term space station experiment for several months, equilibrium temperature T(e) changed, and the actual σ, however, significantly increased mainly due to the increase in salt concentration C(s). To correct σ, the actual C(s) and protein concentration C(p), which correctly represent the measured T(e) value in space, were first calculated. Second, a new solubility curve with the corrected C(s) was plotted. Finally, the revised σ was obtained from the new solubility curve. This correction method successfully revealed that the 2.8% water was evaporated from the solution, leading to 2.8% increase in the C(s) and C(p) of the solution.

Illumina MiSeq Phylogenetic Amplicon Sequencing Shows a Large Reduction of an Uncharacterised Succinivibrionaceae and an Increase of the Methanobrevibacter gottschalkii Clade in Feed Restricted Cattle

Periodic feed restriction is used in cattle production to reduce feed costs. When normal feed levels are resumed, cattle catch up to a normal weight by an acceleration of normal growth rate, known as compensatory growth, which is not yet fully understood. Illumina Miseq Phylogenetic marker amplicon sequencing of DNA extracted from rumen contents of 55 bulls showed that restriction of feed (70% concentrate, 30% grass silage) for 125 days, to levels that caused a 60% reduction of growth rate, resulted in a large increase of relative abundance of Methanobrevibacter gottschalkii clade (designated as OTU-M7), and a large reduction of an uncharacterised Succinivibrionaceae species (designated as OTU-S3004). There was a strong negative Spearman correlation (ρ = -0.72, P = <1x10-20) between relative abundances of OTU-3004 and OTU-M7 in the liquid rumen fraction. There was also a significant increase in acetate:propionate ratio (A:P) in feed restricted animals that showed a negative Spearman correlation (ρ = -0.69, P = <1x10-20) with the relative abundance of OTU-S3004 in the rumen liquid fraction but not the solid fraction, and a strong positive Spearman correlation with OTU-M7 in the rumen liquid (ρ = 0.74, P = <1x10-20) and solid (ρ = 0.69, P = <1x10-20) fractions. Reduced A:P ratios in the rumen are associated with increased feed efficiency and reduced production of methane which has a global warming potential (GWP 100 years) of 28. Succinivibrionaceae growth in the rumen was previously suggested to reduce methane emissions as some members of this family utilise hydrogen, which is also utilised by methanogens for methanogenesis, to generate succinate which is converted to propionate. Relative abundance of OTU-S3004 showed a positive Spearman correlation with propionate (ρ = 0.41, P = <0.01) but not acetate in the liquid rumen fraction.

The thiG Gene Is Required for Full Virulence of Xanthomonas oryzae pv. oryzae by Preventing Cell Aggregation.

Bacterial blight of rice is an important serious bacterial diseases of rice in many rice-growing regions, caused by Xanthomonas oryzae pv. oryzae (Xoo). The thiG gene from Xoo strain ZJ173, which is involved with thiazole moiety production in the thiamine biosynthesis pathway, is highly conserved among the members of Xanthomonas. The thiG deletion mutant displayed impaired virulence and growth in thiamine-free medium but maintained its normal growth rate in the rice tissues, indicating that the thiG gene is involved in Xoo virulence. Compared to the wild type strain, the formation of cell-cell aggregates was affected in thiG deletion mutants. Although biofilm formation was promoted, motility and migration in rice leaves were repressed in the thiG mutants, and therefore limited the expansion of pathogen infection in rice. Quorum sensing and extracellular substance are two key factors that contribute to the formation of cell-cell aggregates. Our study found that in the thiG mutant the expression of two genes, rpfC and rpfG, which form a two-component regulatory signal system involved in the regulation of biofilm formation by a second messenger cyclic di-GMP is down-regulated. In addition, our study showed that xanthan production was not affected but the expression of some genes associated with xanthan biosynthesis, like gumD, gumE, gumH and gumM, were up-regulated in thiG mutants. Taken together, these findings are the first to demonstrate the role of the thiazole biosynthsis gene, thiG, in virulence and the formation of aggregates in Xanthomonas oryzae pv. oryzae.

Arabidopsis ACT11 modifies actin turnover to promote pollen germination and maintain the normal rate of tube growth.

Actin is an ancient conserved protein that is encoded by multiple isovariants in multicellular organisms. There are eight functional actin genes in the Arabidopsis genome, and the precise function and mechanism of action of each isovariant remain poorly understood. Here, we report the characterization of ACT11, a reproductive actin isovariant. Our studies reveal that loss of function of ACT11 causes a delay in pollen germination, but enhances pollen tube growth. Cytological analysis revealed that the amount of filamentous actin decreased, and the rate of actin turnover increased in act11 pollen. Convergence of actin filaments upon the germination aperture was impaired in act11 pollen, consistent with the observed delay of germination. Reduction of actin dynamics with jasplakinolide suppressed the germination and tube growth phenotypes in act11 pollen, suggesting that the underlying mechanisms involve an increase in actin dynamics. Thus, we demonstrate that ACT11 is required to maintain the rate of actin turnover in order to promote pollen germination and maintain the normal rate of pollen tube growth.

Red Blood Cell Storage in Transfusion-Related Acute Gut Injury

Transfusion-related acute gut injury is defined as the occurrence of necrotizing enterocolitis 48 hours or less after a packed red blood cell (PRBC) transfusion for marked anemia in older, low-risk infants born at extremely low gestational ages (&amp;lt;28 weeks’ gestational age) who are no longer experiencing any historically associated risk factors except enteral feeding. As oxygen delivery decreases with advancing anemia, growing premature neonates compensate by redistribution of blood flow, increased cardiac output, and elevated oxygen extraction. Further adjustments to microvascular blood flow arise from nitric oxide–based hypoxic vasodilation, which eventually becomes limiting for sustaining oxygen consumption. Among many effects on red blood cells (RBC), storage lowers donor RBC nitric oxide content and increases free hemoglobin nitric oxide scavenging, whereas low oxygenation reduces nitric oxide production by endothelial nitric oxide synthase; these varied mechanisms collectively result in mitigation of hypoxic vasodilation. Because the adverse effect of packed RBCs on neonatal gut oxygenation appears primarily in association with extreme anemia, a sudden reduction in mucosal blood flow during periods of increased oxygen demand (enteral feeding) presumably results in injury to the physical barrier, enabling bacterial invasion and necrotizing enterocolitis. In infants born at extremely low gestational ages, PRBC transfusions for iatrogenic or developmentally acquired anemia are common and will persist even after all conservation techniques, microassay methods, and use of erythropoietin have been implemented. A fixed need for transfusions exists because of additional biologic restrictions imposed by normal rates of human somatic growth coupled with limits of RBC production to accommodate the need for an expanding RBC mass. Improved understanding of etiologic mechanisms of microvascular injury with transfusion should be instructive to clinicians in managing this dilemma.

Growth Rate of Cosmological Perturbations at z∼0.1 from a New Observational Test.

Spatial variations in the distribution of galaxy luminosities, estimated from redshifts as distance proxies, are correlated with the peculiar velocity field. Comparing these variations with the peculiar velocities inferred from galaxy redshift surveys is a powerful test of gravity and dark-energy theories on cosmological scales. Using ∼2×10(5) galaxies from the SDSS Data Release 7, we perform this test in the framework of gravitational instability to estimate the normalized growth rate of density perturbations fσ8=0.37±0.13 at z∼0.1, which is in agreement with the cold dark matter model with a cosmological constant. This unique measurement is complementary to those obtained with more traditional methods, including clustering analysis. The estimated accuracy at z∼0.1 is competitive with other methods when applied to similar data sets.

SWAP-70 contributes to spontaneous transformation of mouse embryo fibroblasts

Mouse embryo fibroblasts (MEFs) grow slowly after cultivation from animals, however, after an extended period of cultivation, their growth accelerates. We found that SWAP-70 deficient MEFs failed to increase growth rates. They maintain normal growth rates and proliferation cycles for at least 5 years. Complementing SWAP-70 deficiency in one of these MEF clones, MEF1F2, by expressing human SWAP-70 resulted in fast growth of the cells after further cultivation for a long period. The resulting cells show a transformation phenotype, since they grow on top of each other and do not show contact inhibition. This phenotype was reverted when sanguinarine, a putative SWAP-70 inhibitor, was added. Two SWAP-70 expressing clones were examined in detail. Even after cell density became very high their cdc2 and NFκB were still activated suggesting that they do not stop growing. One of the clones formed colonies in soft agar and formed tumors in nude mice. Lately, one more clone became transformed being able to make colonies in soft agar. We maintain 4 human SWAP-70 expressing MEF1F2 cell lines. Three out of 4 clones exhibited transforming phenotypes. The mouse SWAP-70 gene also promoted transformation of MEFs. Taken together our data suggest that SWAP-70 is not a typical oncogene, but is required for spontaneous transformation of MEFs.

Hepatic SirT1-Dependent Gain of Function of Stearoyl-CoA Desaturase-1 Conveys Dysmetabolic and Tumor Progression Functions.

Obesity is associated with higher incidence of cancer, but the predisposing mechanisms remain poorly understood. The NAD(+)-dependent deacetylase SirT1 orchestrates metabolism, cellular survival, and growth. However, there is no unifying mechanism to explain the metabolic and tumor-related effects of SirT1. In this work, we demonstrate that genetic ablation of the endogenous inhibitor of SirT1, Deleted-in-Breast-Cancer-1 (Dbc1), unexpectedly results in obesity and insulin resistance. Dbc1 deficiency promoted SirT1-dependent gain of function of stearoyl-coenzyme A desaturase 1 (Scd1), increasing plasma and tissue levels of unsaturated fatty acids. The metabolic abnormalities in Dbc1(-/-) mice were reversed by ablation of hepatic SirT1 or by inhibition of Scd1 activity. Furthermore, loss of Dbc1 impaired activation of the master tumor suppressor p53 and treatment with an Scd1 inhibitor extended survival of tumor-prone TP53(-/-) mice by decreasing tumor-related death. Together, our findings illustrate a shared mechanism of obesity and tumor progression mediated by hepatic SirT1 and resulting in the activation of a key lipid synthetic enzyme, with potential therapeutic implications.

Growth Rate Dispersion at the Single‐Crystal Level

AbstractEvidence of growth rate dispersion for symmetry‐related opposite faces of centrosymmetric single crystals of ammonium perchlorate is provided. Crystallization experiments conducted by evaporation of a stagnant aqueous solution at room temperature show that some $ ({\rm{hkl}}) $ faces have high and irregular normal growth rates, in time and space, whereas the corresponding $ ({\rm{\overline h}}\;{\rm{\overline k}}\;{\rm{\overline l}}) $ faces crystallize slowly and steadily. The $ ({\rm{hkl}}) $ faces presenting high and irregular crystal growth also form repetitive inclusions, whereas $ ({\rm{\overline h \;\overline k \; \overline l}}) $ faces are not involved in any formation of vacuoles. As a consequence, it is possible to retrace the crystallization history of a single crystal by analyzing the location of series of inclusions showing the progressive displacement of its center of gravity.

Spiral Growth Can Enhance Both the Normal Growth Rate and Quality of Tetragonal Lysozyme Crystals Grown under a Forced Solution Flow

We measured the normal growth rate of the {110} face (R110) of tetragonal lysozyme crystals grown by the spiral growth mechanism or the two-dimensional (2D) nucleation growth mechanism under various solution flow rates (0, 8.0, 30, 140, 210 μm/s), and observed the step morphology using laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM). The R110 of crystals grown by the spiral growth mechanism was enhanced by solution stirring at all solution flow rates. The aspect ratio, which was defined as the ratio of the long axis to the short axis of the hillock shape, increased at a flow rate under 140 μm/s with increasing flow rate; that is, impurities were adsorbed less onto the crystal surface at 140 μm/s, and the aspect ratio decreased monotonically as the solution flow rate increased; that is, the impurity effect became more significant. Thes...

Intrinsic Instability of Three-Dimensional Premixed Flames Under Low- and High-Temperature Conditions: Effects of Unburned-Gas Temperature on Hydrodynamic and Diffusive-Thermal Instabilities

The intrinsic instability of three-dimensional (3D) premixed flames under low- and high-temperature conditions was numerically treated to study the effects of unburned-gas temperature on hydrodynamic and diffusive-thermal instabilities. Superimposing a sinusoidal disturbance with sufficiently small amplitude on a planar flame, we obtained the relation between the growth rate and wave number, i.e., the dispersion relation. As the unburned-gas temperature became lower, the growth rate decreased and the unstable range narrowed due to the decrease of the burning velocity of a planar flame. At sufficiently small wave numbers, the obtained numerical results were consistent with the theoretical solutions. When the Lewis number was small, we obtained a large growth rate and wide unstable range due to diffusive-thermal effects. The growth rate and wave number were normalized by the burning velocity of a planar flame and preheat zone thickness. The normalized growth rate increased and the normalized unstable range widened with a decrease of unburned-gas temperature. This was because thermal-expansion effects became stronger owing to the increase of the temperature ratio of burned and unburned gases. To elucidate the characteristics of cellular flames generated by intrinsic instability, we superimposed a disturbance with the critical wave number corresponding to the maximum growth rate, i.e., the linearly most unstable wave number. The superimposed disturbance evolved, and a hexagonal cellular flame formed. The behavior of cellular flames became stronger as the unburned-gas temperature became lower, even though the growth rate decreased. The burning velocity of a cellular flame normalized by that of a planar flame increased due to the strength of thermal-expansion effects.

Effects of inhibitory compounds in lignocellulosic hydrolysates on Mortierella isabellina growth and carbon utilization

Oleaginous fungus Mortierella isabellina showed excellent lipid conversion on non-detoxified lignocellulosic hydrolysate. This study investigated the effects of inhibitory compounds (furfural, hydroxymethylfurfural, and ferulic and coumaric acids) in lignocellulosic hydrolysate on M. isabellina growth and lipid production. M. isabellina can tolerate furfural (∼1g/L), hydroxymethylfurfural (∼2.5g/L), ferulic (∼0.5g/L) and coumaric acid (∼0.5g/L) with normal growth rates. Synergistic effect of these inhibitors (2g/L furfural, 0.4g/L hydroxymethylfurfural, 0.02g/L ferulic acid and 0.02g/L coumaric acid) moderately reduces total fungal growth (by 28%), while the presence of these inhibitors has minor impact on cell lipid contents and lipid profiles. In the presence of inhibitory compounds, 13C-tracing has revealed that M. isabellina can simultaneously utilize glucose and acetate, and acetate is mainly assimilated for synthesis of lipid and TCA cycle amino acids. The results also demonstrate that glucose has strong catabolite repression for xylose utilization for biomass and lipid production in the presence of inhibitors.

WATER QUALITY AND ITS EFFECT ON GROWTH AND SURVIVAL RATE OF LOBSTER REARED IN FLOATING NET CAGE IN EKAS BAY, WEST NUSA TENGGARA PROVINCE

ABSTRACT The development of lobster farming in floating net cage in Ekas Bay caused an environmental degradation such as decrease water quality due to some aquaculture wastes. The purposes of this study were to determine the status of water quality and their effect on growth and survival rate of lobster reared in floating net cages (FNC) in the Ekas Bay, West Nusa Tenggara Province. Water sample collection and handling referred to the APHA (1992). Analyses of water quality data were conducted using Principal Component Analysis. Determination of the water quality status of Ekas Bay was performed with STORET system. Multivariate analyses were used to determine the relationship between water quality, growth, and survival rate of lobster reared in FNC. Results showed that Ekas Bay water quality status was categorized in class C (medium contaminated), which exceeded some quality standard parameters such as ammonia (0.3 mg/l), nitrate (0.008 mg/l), and phosphate (0.015 mg/l). During lobster farming activities feeding with trash fish for 270 days, we obtained daily growth rate of 0.74% (lower than normal growth rate of 0.86%), survival rate of 66% (lower than normal survival rate of 86.7%), and feed conversion ratio of 11.15. Ammonia was found as a dominant factor reducing growth and survival rate of lobster reared in FNC. Keywords: water quality, lobsters, growth, survival, Ekas Bay

WATER QUALITY AND ITS EFFECT ON GROWTH AND SURVIVAL RATE OF LOBSTER REARED IN FLOATING NET CAGE IN EKAS BAY, WEST NUSA TENGGARA PROVINCE

&lt;p&gt;&lt;strong&gt;&lt;em&gt;ABSTRACT&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;&lt;em&gt;The development of lobster farming in floating net cage in Ekas Bay caused an environmental degradation such as decrease water quality due to some aquaculture wastes. The purposes of this study were to determine the status of water quality and their effect on growth and survival rate of lobster reared in floating net cages (FNC) in the Ekas Bay, West Nusa Tenggara Province. Water sample collection and handling referred to the APHA (1992). Analyses of water quality data were conducted using Principal Component Analysis. Determination of the water quality status of Ekas Bay was performed with STORET system. Multivariate analyses were used to determine the relationship between water quality, growth, and survival rate of lobster reared in FNC. Results showed that Ekas Bay water quality status was categorized in class C (medium contaminated), which exceeded some quality standard parameters such as ammonia (0.3 mg/l), nitrate (0.008 mg/l), and phosphate (0.015 mg/l). During lobster farming activities feeding with trash fish for 270 days, we obtained daily growth rate of 0.74% (lower than normal growth rate of 0.86%), survival rate of 66% (lower than normal survival rate of 86.7%), and feed conversion ratio of 11.15. Ammonia was found as a dominant factor reducing growth and survival rate of lobster reared in FNC.&lt;/em&gt;&lt;/p&gt; &lt;p&gt;&lt;em&gt; &lt;/em&gt;&lt;/p&gt; &lt;strong&gt;&lt;em&gt;Keywords:&lt;/em&gt;&lt;/strong&gt;&lt;em&gt; water quality, lobsters, growth, survival, Ekas Bay&lt;/em&gt;

Normal Pregnancy and Lactation in a Cat after Treatment of Mammary Gland Tumor When Using Photothermal Therapy with Gold Nanorods: A Case Report

Background: Breast cancer therapy, which includes surgery, radiotherapy, chemotherapy and/or systemic therapy can have a profound impact on reproductive functions, leading to loss of fertility. To our knowledge, this is the first report on cancer photothermal therapy using gold nanorods on the mammary gland treatment of a cat, and the safe effect of the treatment on the reproductive function after tumor remission. Case presentation: A seven years old Shirazi cat (Toatoa) was evaluated because of a 2-week history of progressive dyspnea, signs of depression, and loss of appetite. The cat has a large tumor mass at the left caudal mammary gland. The diameter of the tumor mass was measured using caliper with the dimensions of 14 × 12 × 10.5 cm for length, width and depth, respectively. This was confirmed with ultrasonography. Biopsy samples were taken and fixed in 10% formalin for histopathological investigation, and it was diagnosed as mammary gland adenocarcinoma Grade II. Toatoa was injected intratumoral (IT) with 75 μg gold nanorods (GNRs)/kg body weight followed by exposure to 808 nm laser light for 10 min. GNRs were injected twice, with 15 days apart. After 15 days from the first GNRs injection, there was 60% ablation of the tumor size, while, after 17 days from the second GNRs dose, there was a complete tumor remission. Ultrasound scanning revealed complete ablation of the tumor mass. Complete blood picture (CBC), liver and kidney function analyses showed no changes in any of the tested parameters and indicated that GNRs photothermal treatment is safe and have no immediate toxic effects. After complete remission of the mammary gland tumor, the cat restores all the biological activities including the reproductive function. After 2 months from complete tumor remission, the cat was pregnant after mating with a fertile male, and 62 days later she delivered 3 kittens of normal morphology and growth rate. Breast feeding was found to be normal from all the nipples including the previously affected nipple. Conclusion: Photothermal therapy with gold nanorods can be used for the treatment of mammary gland tumor with apparently no impairments of reproductive functions in cats.

Influence of Degrading Calcium Phosphate on the Remodelling and Mineralisation of Avascular Osseous Tissue in a Rat Calvaria Model

Artificial bone graftingis the subject of intensive investigation for craniofacial reconstruction. Among the syntheticcandi date materials, those incorporating Calcium Phosphates (CaP) have gained popularity, due to their osteoinductive properties. Despite many quantitative studies on the degradation rates of CaP biomaterials in vitro, there is lack of quantitative studies in relation to bone remodelling kinetics in vivo. In this investigation, we tested implants of degradable CaP/chitosan-based biomaterial in a rat calvaria model of critical-sized defects. We observed remarkable acceleration of bone growth in the initial stages (~0.8 g/day), which was markedly higher than normal bone growth rates (~0.1 g/day) in implant-free controls. The implanted CaP-based biomaterial significantly enhanced bone formation, with woven bone seen as early as 20 days and lamellar bone at 40 and 60 days post-implantation. However the mineralisation of cortical bone was delayed, due to the overly rapid degradation of the biomaterial: This therapeutically important issue has never been identified before to our best knowledge. A theoretical analysis revealed that during degradation CaP can be rapidly released from the new bone matrix. Hence, while the degradable CaP biomaterial was found to be highly osteoconductive in vivo, future modifications would seek to optimize degradation efficiency for more sustained release of mineral ions, to enhance bone mineralisation at later stages of the healing process after implantation.

極低温環境における予混合火炎の固有不安定性（未燃ガス温度と熱損失の影響）

The effects of unburned-gas temperature and radiative heat loss on the intrinsic instability of premixed flames in cryogenic environment were studied. Unsteady reactive flow was calculated numerically, based on the compressible Navier-Stokes equation including chemical reaction and radiative heat loss. As the unburned-gas temperature became lower, the growth rate decreased and the unstable range narrowed, which was due to the reduction of the burning velocity of a planar flame. Considering radiative heat loss, the growth rate was smaller and the unstable range was narrower. On the other hand, the normalized growth rate increased as the unburned-gas temperature became lower. This was due to the strength of thermal-expansion effects and to the enlargement of Zeldovich numbers. Furthermore, cellular flames appeared owing to intrinsic instability. As the unburned-gas temperature became lower, the normalized burning velocity of a cellular flame increased. When radiative heat loss was considered, the normalized burning velocity of a cellular flame increased at small Lewis numbers and remained at Lewis number of unity.

A role for Galgt1 in skeletal muscle regeneration.

BackgroundCell surface glycans are known to play vital roles in muscle membrane stability and muscle disease, but to date, roles for glycans in muscle regeneration have been less well understood. Here, we describe a role for complex gangliosides synthesized by the Galgt1 gene in muscle regeneration.MethodsCardiotoxin-injected wild type (WT) and Galgt1−/− muscles, and mdx and Galgt1−/−mdx muscles, were used to study regeneration in response to acute and chronic injury, respectively. Muscle tissue was analyzed at various time points for morphometric measurements and for gene expression changes in satellite cell and muscle differentiation markers by quantitative real-time polymerase chain reaction (qRT-PCR). Primary cell cultures were used to measure growth rate and myotube formation and to identify Galgt1 expression changes after cardiotoxin by fluorescence-activated cell sorting (FACS). Primary cell culture and tissue sections were also used to quantify satellite cell apoptosis.ResultsA query of a microarray data set of cardiotoxin-induced mouse muscle gene expression changes identified Galgt1 as the most upregulated glycosylation gene immediately after muscle injury. This was validated by qRT-PCR as a 23-fold upregulation in Galgt1 expression 1 day after cardiotoxin administration and a 16-fold upregulation in 6-week-old mdx muscles. These changes correlated with increased expression of Galgt1 protein and GM1 ganglioside in mononuclear muscle cells. In the absence of Galgt1, cardiotoxin-induced injury led to significantly reduced myofiber diameters after 14 and 28 days of regeneration. Myofiber diameters were also significantly reduced in Galgt1-deficient mdx mice compared to age-matched mdx controls, and this was coupled with a significant increase in the loss of muscle tissue. Cardiotoxin-injected Galgt1−/− muscles showed reduced gene expression of the satellite cell marker Pax7 and increased expression of myoblast markers MyoD, Myf5, and Myogenin after injury along with a tenfold increase in apoptosis of Pax7-positive muscle cells. Cultured primary Galgt1−/− muscle cells showed a normal growth rate but demonstrated premature fusion into myofibers, resulting in an overall impairment of myofiber formation coupled with a threefold increase in muscle cell apoptosis.ConclusionsThese experiments demonstrate a role for Galgt1 in skeletal muscle regeneration and suggest that complex gangliosides made by Galgt1 modulate the survival and differentiation of satellite cells.

Macroscopic Approach to the Nucleation and Propagation of Foreign Polytype Inclusions during Seeded Sublimation Growth of Silicon Carbide

The nucleation and propagation of foreign polytypes during seeded sublimation growth of silicon carbide is addressed on a macroscopic footing, using a coupled experimental and numerical simulation approach. Experiments are conducted in a contactless growth geometry for different seed substrates with varying polarity, miscut angle, polytype, and crystal shape (concave and convex). The interface shape evolution is tracked by periodic nitrogen marking, which also allows the measurement of lateral and normal growth rates at any time during growth. Classical 2D nucleation theory is included in modeling the full process, and this is compared to experiments. We demonstrate that the occurrence of a foreign polytype is linked to the combined effects of (i) the presence of the natural {0001} facets and (ii) the minimization of 2D nucleation energy. Areas with a high probability of foreign polytype nucleation can thus be predicted. Once formed, the progress or disappearance of foreign inclusions is directly related ...