Do changes in transglutaminase activity alter latent transforming growth factor beta activation in experimental diabetic nephropathy?

Background. Diabetic nephropathy is the leading cause of end-stage kidney failure worldwide. It is characterized by excessive extracellular matrix accumulation. Transforming growth factor beta 1 (TGF-ß1) is a fibrogenic cytokine playing a major role in the healing process and scarring by regulating extracellular matrix turnover, cell proliferation and epithelial mesanchymal transdifferentiation. Newly synthesized TGF-ß is released as a latent, biologically inactive complex. The cross-linking of the large latent TGF-ß to the extracellular matrix by transglutaminase 2 (TG2) is one of the key mechanisms of recruitment and activation of this cytokine. TG2 is an enzyme catalyzing an acyl transfer reaction leading to the formation of a stable e(?-glutamyl)-lysine cross-link between peptides.Methods. To investigate if changes in TG activity can modulate TGF-ß1 activation, we used the mink lung cell bioassay to assess TGF-ß activity in the streptozotocin model of diabetic nephropathy treated with TG inhibitor NTU281 and in TG2 overexpressing opossum kidney (OK) proximal tubular epithelial cells.Results. Application of the site-directed TG inhibitor NTU281 caused a 25% reduction in kidney levels of active TGF-ß1. Specific upregulation of TG2 in OK proximal tubular epithelial cells increased latent TGF-ß recruitment and activation by 20.7% and 19.7%, respectively, in co-cultures with latent TGF-ß binding protein producing fibroblasts.Conclusions. Regulation of TG2 directly influences the level of active TGF-ß1, and thus, TG inhibition may exert a renoprotective effect by targeting not only a direct extracellular matrix deposition but also TGF-ß1 activation and recruitment.

Growth phases in the life of a lichen thallus

The growth rates of thalli of foliose saxicolous lichens before and after the linear phase of growth were measured in 1973. Changes in the radial growth rate (measured as mm/year) with thallus size in the prelinear phase (thalli less than approximately 1.5 cm in diameter) were consistent with the hypothesis that early growth of these lichens is loagarithmic. When growth in the prelinear phase was measured as a relative growth rate (measured as sq cm/sq cm/year) there was a rapid rise in growth rate until about 3 mm thallus diameter and then a decline in growth rate. The radial growth rate of non-fragmenting thalli when compared with fragmenting thalli at different stages of fragmentation suggested that radial growth rate does not significantly decline after fragmentation of the thallus. This result is not consistent with a postlinear phase in the radial growth of a lichen thallus.

Growth of crustose lichens: a review

Crustose species are the slowest growing of all lichens. Their slow growth and longevity, especially of the yellow-green Rhizocarpon group, has made them important for surface-exposure dating (‘lichenometry’). This review considers various aspects of the growth of crustose lichens revealed by direct measurement including: 1) early growth and development, 2) radial growth rates (RGR, mm yr-1), 3) the growth rate-size curve, and 4) the influence of environmental factors. Many crustose species comprise discrete areolae that contain the algal partner growing on the surface of a non-lichenised fungal hypothallus. Recent data suggest that ‘primary’ areolae may develop from free-living algal cells on the substratum while ‘secondary’ areolae develop from zoospores produced within the thallus. In more extreme environments, the RGR of crustose species may be exceptionally slow but considerably faster rates of growth have been recorded under more favourable conditions. The growth curves of crustose lichens with a marginal hypothallus may differ from the ‘asymptotic’ type of curve recorded in foliose and placodioid species and the latter are characterized by a phase of increasing RGR to a maximum and may be followed by a phase of decreasing growth. The decline in RGR in larger thalli may be attributable to a reduction in the efficiency of translocation of carbohydrate to the thallus margin or to an increased allocation of carbon to support mature ‘reproductive’ areolae. Crustose species have a low RGR accompanied by a low demand for nutrients and an increased allocation of carbon for stress resistance; therefore enabling colonization of more extreme environments.

Growth of foliose lichens: a review

This review considers various aspects of the growth of foliose lichens including early growth and development, variation in radial growth rate (RaGR) of different species, growth to maturity, lobe growth variation, senescence and fragmentation, growth models, the influence of environmental variables, and the maintenance of thallus symmetry. The data suggest that a foliose lichen thallus is essentially a ‘colony’ in which the individual lobes exhibit a considerable degree of autonomy in their growth processes. During development, recognisable juvenile thalli are usually formed by 15 months to 4 years while most mature thalli exhibit RaGR between 1 and 5 mm yr-1. RaGR within a species is highly variable. The growth rate-size curve of a foliose lichen thallus may result from growth processes that take place at the tips of individual lobes together with size-related changes in the intensity of competition for space between the marginal lobes. Radial growth and growth in mass is influenced by climatic and microclimatic factors and also by substratum factors such as rock and bark texture, chemistry, and nutrient enrichment. Possible future research topics include: (1) measuring fast growing foliose species through life, (2) the three dimensional changes that occur during lobe growth, (3) the cellular changes that occur during regeneration, growth, and division of lobes, and (4) the distribution and allocation of the major lichen carbohydrates within lobes.

Can hydrogen sulfide prevent preeclampsia and fetal growth restriction?

The exact aetiology of preeclampsia is unknown, but there is a good association with an imbalance in angiogenic growth factors and abnormal placentation [1]. Hydrogen sulphide (H2S), a gaseous messenger produced mainly by cystathionine γ-lyase (CSE), is pro-angiogenic vasodilator [2] and [3]. We hypothesized that a reduction in CSE activity may alter the angiogenic balance in pregnancy and induce abnormal placentation and maternal hypertension. Plasma levels of H2S were significantly decreased in preeclamptic women (p < 0.01), which was associated with reduced CSE message and protein expression in human placenta as determined by real-time PCR and immunohistochemistry. Inhibition of CSE activity by DL-propargylglycine (PAG) in first trimester (8–12 weeks gestation) human placental explants had reduced placenta growth factor (PlGF) production as assessed by ELISA and inhibited trophoblast invasion in vitro. Endothelial CSE knockdown by siRNA transfection increased the endogenous release of soluble fms-Like tyrosine kinase-1 (sFlt-1) and soluble endoglin, (sEng) from human umbilical vein endothelial cells while adenoviral-mediated CSE overexpression inhibited their release. Administration of PAG to pregnant mice induced hypertension, liver damage, and promoted abnormal labyrinth vascularisation in the placenta and decreased fetal growth. Finally, a slow releasing, H2S-generating compound, GYY4137, inhibited circulating sFlt-1 and sEng levels and restored fetal growth that was compromised by PAG-treatment demonstrating that the effect of CSE inhibitor was due to inhibition of H2S production. These results imply that endogenous H2S is required for healthy placental vasculature and a decrease in of CSE/H2S activity may contribute to the pathogenesis of preeclampsia. References [1] S. Ahmad, A. Ahmed, Elevated placental soluble vascular endothelial growth factor receptor-1 inhibits angiogenesis in preeclampsia, Circ Res., 95 (2004), pp. 884–891. [2] G. Yang, et al., H2S as a physiologic vasorelaxant: hypertension in mice with deletion of cystathionine gamma-lyase, Science, 322 (2008), pp. 587–590. [3] A. Papapetropoulos, et al., Hydrogen sulfide is an endogenous stimulator of angiogenesis, Proc Natl Acad Sci USA, 106 (2009), pp. 21972–21977.

Data compilation of ciliates growth rate, grazing rate and gross gowth efficiency from field and labratory experiments

The present data compilation includes ciliates growth rate, grazing rate and gross growth efficiency determined either in the field or in laboratory experiments. From the existing literature, we synthesized all data that we could find on cilliate. Some sources might be missing but none were purposefully ignored. Field data on microzooplankton grazing are mostly comprised of grazing rate using the dilution technique with a 24h incubation period. Laboratory grazing and growth data are focused on pelagic ciliates and heterotrophic dinoflagellates. The experiment measured grazing or growth as a function of prey concentration or at saturating prey concentration (maximal grazing rate). When considering every single data point available (each measured rate for a defined predator-prey pair and a certain prey concentration) there is a total of 1485 data points for the ciliates, counting experiments that measured growth and grazing simultaneously as 1 data point.

Extracellular matrix sub-types and mechanical stretch impact human cardiac fibroblast responses to transforming growth factor beta

Understanding the impact of extracellular matrix sub-types and mechanical stretch on cardiac fibroblast activity is required to help unravel the pathophysiology of myocardial fibrotic diseases. Therefore, the purpose of this study was to investigate pro-fibrotic responses of primary human cardiac fibroblast cells exposed to different extracellular matrix components, including collagen sub-types I, III, IV, VI and laminin. The impact of mechanical cyclical stretch and treatment with transforming growth factor beta 1 (TGFβ1) on collagen 1, collagen 3 and alpha smooth muscle actin mRNA expression on different matrices was assessed using quantitative real-time PCR. Our results revealed that all of the matrices studied not only affected the expression of pro-fibrotic genes in primary human cardiac fibroblast cells at rest but also affected their response to TGFβ1. In addition, differential cellular responses to mechanical cyclical stretch were observed depending on the type of matrix the cells were adhered to. These findings may give insight into the impact of selective pathological deposition of extracellular matrix proteins within different disease states and how these could impact the fibrotic environment.

Foliar phosphorus application enhances nutrient balance and growth of phosphorus deficient sugarcane

Although it is well known that nutrient imbalance in shoot tissues may impair plant performance, the interactive effect between foliar phosphorus (P) application and varying P availability in the rooting medium on the nutritional status of sugarcane has not been well studied. To fill this research gap, four sugarcane varieties (IAC91-1099, IACSP94-2101, IACSP94-2094 and IACSP95-5000) were evaluated using a combination of two concentrations of P in nutrient solution (P-deficient, PD = 0.02 mmol L^(−1) and P-sufficient, PS = 0.5 mmol L^(−1)) and foliar P application (none and 0.16 mol L^(−1)). The spray was applied until drip point three times during the experiment with 15 days intervals, after which the plants were harvested to quantify growth and shoot concentration of nitrogen (N), P, magnesium (Mg), sulphur (S) and manganese (Mn). The responses of sugarcane plants to foliar P spray at different levels of P supply in the rooting medium was not genotype-dependent. It was demonstrated for the averaged values across varieties, that foliar P application enhanced sugarcane performance under low P, as revealed by improvements of leaf area and dry matter production of shoot and root of PD plants. Under P limitation we also observed diminished shoot concentration of N, P, Mg, S and increased concentration of Mn. However, foliar P spray increased the concentrations of N, P, S and reduced shoot Mn. Furthermore, shoot P:N, P:Mg, P:S, P:Mn and Mg:Mn concentration ratios exhibited a positive relationship with shoot dry matter production. In conclusion, low P supply in the rooting medium impairs nutrient balance in shoot tissues of sugarcane at early growth; however, this effect was ameliorated by foliar P application which merits further study under field conditions.

Salicaceae Endophytes: Growth Promotion Potential in Rice (Oryza sativa L.) and Maize (Zea mays L.) and Bio-Control of Plant Pathogen

Thesis (Ph.D.)--University of Washington, 2016-08

Agrandissement des feuillets mitraux en insuffisance aortique : un mécanisme actif pouvant prévenir l’insuffisance mitrale dans le ventricule dilaté

L’insuffisance mitrale (IM) fonctionnelle est une complication fréquente des cardiopathies, causée par la dilatation du ventricule gauche (VG) qui empêche la valve de se fermer. L’insuffisance aortique (IA) est une condition associée à des valves mitrales (VM) inhabituellement grandes, et relativement peu d’IM malgré des VG très dilatés. Cet élargissement de la VM a le potentiel de prévenir l’IM dans les VG dilatés. Les mécanismes sont cependant peu compris : il n’est pas clair s’il s’agit d’une croissance active ou d’un étirement passif des feuillets. Également, le timing de l’adaptation valvulaire n’est pas connu. Notre hypothèse est que l’agrandissement de la valve mitrale en IA est un phénomène actif avec réactivation des mécanismes de croissance embryonnaire. Cent-onze rats ont été divisés en deux groupes : IA (perforation aortique) et contrôle. Les animaux ont été sacrifiés à 48 h, 1 semaine et 3 mois après la création du modèle. Des échocardiographies ont évalué la sévérité de l’IA, la présence d’IM et les dimensions du VG. Les valves ont été prélevées pour analyses microscopiques et moléculaires. La création de l’insuffisance aortique a entrainé une dilatation et une hypertrophie du VG. Malgré cette dilatation rapide du VG, aucun animal n’a développé de l’IM fonctionnelle. À l’échographie, le feuillet antérieur mitral était significativement plus long dans les groupes IA. Par microscopie, les feuillets étaient plus épais dés la première semaine. L’IA était associée à une surexpression de collagène α-SMA (un marqueur de myofibroblastes), TGF-β1 et MMP-2 dans le tissu valvulaire dès la première semaine. Les valves exposées à l’IA étaient également positives pour ces différents facteurs dés les premiers jours. L’agrandissement de la VM est un phénomène actif qui survient rapidement après la création de l’IA, en parallèle de la dilatation du VG. La stimulation de cette croissance dans d’autres pathologies pourrait contribuer à prévenir l’IM fonctionnelle.

Genome Wide Association Studies of Phagocytosis and the Cellular Immune Response in Drosophila melanogaster.

Phagocytosis of bacteria by specialized blood cells, known as hemocytes, is a vital component of Drosophila cellular immunity. To identify novel genes that mediate the cellular response to bacteria, we conducted three separate genetic screens using the Drosophila Genetic Reference Panel (DGRP). Adult DGRP lines were tested for the ability of their hemocytes to phagocytose the Gram-positive bacteria Staphylococcus aureus or the Gram-negative bacteria Escherichia coli. The DGRP lines were also screened for the ability of their hemocytes to clear S. aureus infection through the process of phagosome maturation. Genome-wide association analyses were performed to identify potentially relevant single nucleotide polymorphisms (SNPs) associated with the cellular immune phenotypes. The S. aureus phagosome maturation screen identified SNPs near or in 528 candidate genes, many of which have no known role in immunity. Three genes, dpr10, fred, and CG42673, were identified whose loss-of-function in blood cells significantly impaired the innate immune response to S. aureus. The DGRP S. aureus screens identified variants in the gene, Ataxin 2 Binding Protein-1 (A2bp1) as important for the cellular immune response to S. aureus. A2bp1 belongs to the highly conserved Fox-1 family of RNA-binding proteins. Genetic studies revealed that A2bp1 transcript levels must be tightly controlled for hemocytes to successfully phagocytose S. aureus. The transcriptome of infected and uninfected hemocytes from wild type and A2bp1 mutant flies was analyzed and it was found that A2bp1 negatively regulates the expression of the Immunoglobulin-superfamily member Down syndrome adhesion molecule 4 (Dscam4). Silencing of A2bp1 and Dscam4 in hemocytes rescues the fly’s immune response to S. aureus indicating that Dscam4 negatively regulates S. aureus phagocytosis. Overall, we present an examination of the cellular immune response to bacteria with the aim of identifying and characterizing roles for novel mediators of innate immunity in Drosophila. By screening panel of lines in which all genetic variants are known, we successfully identified a large set of candidate genes that could provide a basis for future studies of Drosophila cellular immunity. Finally, we describe a novel, immune-specific role for the highly conserved Fox-1 family member, A2bp1.

Transcription of TIR1-Controlled Genes Can be Regulated within 10 Min by an Auxin-Induced Process. Can TIR1 be the Receptor?

ABP1 and TIR1/AFBs are known as auxin receptors. ABP1 is linked to auxin responses several of which are faster than 10 min. TIR1 regulates auxin-induced transcription of early auxin genes also within minutes. We use transcription of such TIR1-dependent genes as indicator of TIR1 activity to show the rapid regulation of TIR1 by exogenous auxin. To this end, we used quantification of transcription of a set of fifteen early auxin-induced reporter genes at t = 10 and t = 30 min to measure this as a TIR1-dependent auxin response. We conducted this study in 22 mutants of auxin transporters (pin5, abcb1, abcb19, and aux1/lax3), protein kinases and phosphatases (ibr5, npr1, cpk3, CPK3-OX, d6pk1, d6pkl1-1, d6pkl3-2, d6pkl1-1/d6pkl2-2, and d6pkl1-1/d6pkl3-2), of fatty acid metabolism (fad2-1, fad6-1, ssi2, lacs4, lacs9, and lacs4/lacs9) and receptors (tir1, tir1/afb2, and tir1/afb3) and compared them to the wild type. After 10 min auxin application, in 18 out of 22 mutants mis-regulated expression of at least one reporter was found, and in 15 mutants transcription of two-to-three out of five selected auxin reporter genes was mis-regulated. After 30 min of auxin application to mutant plants, mis-regulation of reporter genes ranged from one to 13 out of 15 tested reporter genes. Those genes chosen as mutants were themselves not regulated in their expression by auxin for at least 1 h, excluding an influence of TIR1/AFBs on their transcription. The expression of TIR1/AFB genes was also not modulated by auxin for up to 3 h. Together, this excludes a feedback or feedforward of these mutant genes/proteins on TIR1/AFBs output of transcription in this auxin-induced response. However, an auxin-induced response needed an as yet unknown auxin receptor. We suggest that the auxin receptor necessary for the fast auxin-induced transcription modulation could be, instead, ABP1. The alternative hypothesis would be that auxin-induced expression of a protein, initiated by TIR1/AFBs receptors, could initiate these responses and that this unknown protein regulated TIR1/AFB activities within 10 min.

The influence of triiodothyronine (T-3) on the early development of piracanjuba (Brycon orbignyanus)

This paper reports the triiodothyronine's (T-3) effects on the early growth and survival of piracanjuba (Brycon orbignyanus) produced from fertilized eggs hormone exposed The study was carried out in two phases In the first phase, eggs divided in 6 batches were Immersed in T-3 solutions 0 01, 0 05, 0 1, 0 5 ppm, 1 ppm and control (no T-3) After a 15-min immersion, eggs were transferred to incubators where larvae were kept up to 72 h after hatching Larval weight, length and yolk sac volume were determined every 12 h Sixty and 72 h after hatching, larvae exposed to 0 5 ppm T-3 were significantly heavier than the others, and those exposed to 1 ppm T-3 showed the lowest weight The yolk sac absorption was not affected In the second experimental phase, the resulting fry from the first phase were stocked into 3 boxes per treatment (5 larvae L-1) and fed with plankton, fish larvae and feed prepared in the hatchery (48% CP) in the first 3 days, plankton and feed from the 4th to the 10th day and only feed in the next (last) 5 days Fry weight, length and specific growth rate were determined at 1, 5, 10 and 15 days Survival was calculated in the last day In the 15th day, fry length did not differ among treatments but the weight of the control group was higher Higher survival in the T-3-treated groups suggested lower predation among fry The results allowed us to conclude that there was no expressive effect of T-3 on the growth, but it improved the survival of the piracanjuba progeny

Angiopoietin-1 promotes atherosclerosis by increasing the proportion of circulating Gr1 monocytes

Atherosclerosis is a chronic inflammatory disease occurring within the artery wall. A crucial step in atherogenesis is the infiltration and retention of monocytes into the subendothelial space of large arteries induced by chemokines and growth factors. Angiopoietin-1 (Ang-1) regulates angiogenesis and reduces vascular permeability and has also 15 been reported to promote monocyte migration in vitro. We investigated the role of Ang-1 in atherosclerosis-prone apolipoprotein-E (Apo-E) knockout mouse. Apo-E knockout (Apo-E-/-) mice fed a western or normal chow diet received a single iv injection of adenovirus encoding Ang-1 or control vector. Adenovirus-mediated systemic expression of Ang-1 induced a significant increase in early atherosclerotic lesion size and monocyte/macrophage accumulation compared with control animals receiving empty vector. Ang-1 significantly increased plasma MCP-1 and VEGF levels as measured by ELISA. FACS analysis showed that Ang-1 selectively increased inflammatory Gr1þmonocytes in the circulation, while the cell-surface 25 expression of CD11b, which mediates monocyte emigration, was significantly reduced. Ang-1 specifically increases circulating Gr1þinflammatory monocytes and increases monocyte/macrophage retention in atherosclerotic plaques, thereby contributing to development of atherosclerosis.

Initiation and early crack growth in VHCF of stainless steels : Experimental and theoretical analysis

Mechanical fatigue is a failure phenomenon that occurs due to repeated application of mechanical loads. Very High Cycle Fatigue (VHCF) is considered as the domain of fatigue life greater than 10 million load cycles. Increasing numbers of structural components have service life in the VHCF regime, for instance in automotive and high speed train transportation, gas turbine disks, and components of paper production machinery. Safe and reliable operation of these components depends on the knowledge of their VHCF properties. In this thesis both experimental tools and theoretical modelling were utilized to develop better understanding of the VHCF phenomena. In the experimental part, ultrasonic fatigue testing at 20 kHz of cold rolled and hot rolled stainless steel grades was conducted and fatigue strengths in the VHCF regime were obtained. The mechanisms for fatigue crack initiation and short crack growth were investigated using electron microscopes. For the cold rolled stainless steels crack initiation and early growth occurred through the formation of the Fine Granular Area (FGA) observed on the fracture surface and in TEM observations of cross-sections. The crack growth in the FGA seems to control more than 90% of the total fatigue life. For the hot rolled duplex stainless steels fatigue crack initiation occurred due to accumulation of plastic fatigue damage at the external surface, and early crack growth proceeded through a crystallographic growth mechanism. Theoretical modelling of complex cracks involving kinks and branches in an elastic half-plane under static loading was carried out by using the Distributed Dislocation Dipole Technique (DDDT). The technique was implemented for 2D crack problems. Both fully open and partially closed crack cases were analyzed. The main aim of the development of the DDDT was to compute the stress intensity factors. Accuracy of 2% in the computations was attainable compared to the solutions obtained by the Finite Element Method.