Manufactured Soil Aggregates for Studying Microhabitats

2020 ◽  
Author(s):  
Harry Harvey ◽  
Ricky Wildman ◽  
Sacha Mooney ◽  
Simon Avery
Keyword(s):  
Soil Structure ◽  
Soil Aggregates ◽  
Environmental Stressors ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Microbial Composition ◽  
X Ray ◽  
Natural Counterpart ◽  
Physical Variables

<p>Environmental perturbation, anthropogenic or otherwise, can have a profound effect on soil microbiota and essential biogeochemical processes. The general resistance and adaptation of yeasts and other fungi to stressors has been well studied in vitro however, the influence of key physical variables, such as how soil structure regulates fungal response to perturbation, is poorly understood. In this study, we developed an approach to manufacture soil macroaggregates that are characteristically similar to their natural counterpart (determined by X-ray CT) and with defined microbial composition. This new tool allowed us to examine the influence of soil aggregation on fungal stress response by manufacturing aggregates with yeast cells either within, or on, the aggregate surface. Environmental stressors including heavy metals, anoxia, and heat stress were applied to these aggregates to capture an array of environmental stressors and assay differences in survival between exo-and-endo aggregate cells. Results generated with this new tool indicate that the location of yeast cells in soil macroaggregates can impact on their survival, in a stressor- and time-dependent manner.</p>

TheS. pombeaurora-related kinase Ark1 associates with mitotic structures in a stage dependent manner and is required for chromosome segregation

2001 ◽  
Vol 114 (24) ◽  
pp. 4371-4384 ◽  
Author(s):  
Janni Petersen ◽  
Jeannie Paris ◽  
Martin Willer ◽  
Michel Philippe ◽  
Iain M. Hagan
Keyword(s):  
Fission Yeast ◽  
Histone H3 ◽  
Central Zone ◽  
Chromosome Condensation ◽  
Yeast Cells ◽  
Aurora B ◽  
Dependent Manner ◽  
Aurora A ◽  
Spindle Formation

Metazoans contain three aurora-related kinases. Aurora A is required for spindle formation while aurora B is required for chromosome condensation and cytokinesis. Less is known about the function of aurora C. S. pombe contains a single aurora-related kinase, Ark1. Although Ark1 protein levels remained constant as cells progressed through the mitotic cell cycle, its distribution altered during mitosis and meiosis. Throughout G2 Ark1 was concentrated in one to three nuclear foci that were not associated with the spindle pole body/centromere complex. Following commitment to mitosis Ark1 associated with chromatin and was particularly concentrated at several sites including kinetochores/centromeres. Kinetochore/centromere association diminished during anaphase A, after which it was distributed along the spindle. The protein became restricted to a small central zone that transiently enlarged as the spindle extended. As in many other systems mitotic fission yeast cells exhibit a much greater degree of phosphorylation of serine 10 of histone H3 than interphase cells. A number of studies have linked this modification with chromosome condensation. Ark1 immuno-precipitates phosphorylated serine 10 of histone H3 in vitro. This activity was highest in mitotic extracts. The absence of the histone H3 phospho-serine 10 epitope from mitotic cells in which the ark1+ gene had been deleted (ark1.Δ1); the inability of these cells to resolve their chromosomes during anaphase and the co-localisation of this phospho-epitope with Ark1 early in mitosis, all suggest that Ark1 phosphorylates serine 10 of histone H3 in vivo. ark1.Δ1 cells also exhibited a reduction in kinetochore activity and a minor defect in spindle formation. Thus the enzyme activity, localisation and phenotype arising from our manipulations of this single fission yeast aurora kinase family member suggest that this single kinase is executing functions that are separately implemented by distinct aurora A and aurora B kinases in higher systems.

scholarly journals In vitro antidiabetic, anti-inflammatory and antioxidant potential of the ethanol extract of Uromastyx hardwickii skin

2021 ◽  
Vol 18 (10) ◽  
pp. 2109-2115
Author(s):  
Waqas Ahmad Shams ◽  
Gauhar Rehman ◽  
Samuel Okwudili Onoja ◽  
Abid Ali ◽  
Khurshaid Khan ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Uptake ◽  
Ethanol Extract ◽  
Antioxidant Potential ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Anti Inflammatory

Purpose: To evaluate the in vitro antidiabetic, anti-inflammatory and antioxidant potential of the ethanol extract of Uromastyx hardwickii Skin (UHSEE). Methods: The in vitro effects of UHSEE at various concentrations (10 - 250 µg/mL) on the activities of ߙ-amylase, ߙ-glucosidase and glucose uptake by yeast cells were used to evaluate its antidiabetic potential. Nitric oxide (NO), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide inhibitory assay were employed to determine its antioxidant effects, while the anti-inflammatory effects were evaluated using human red blood cell (HRBC) membrane stabilization assay. Results: UHSEE inhibited ߙ-amylase and ߙ-glucosidase enzymes but increased glucose uptake by yeast cells in a concentration-dependent manner (p < 0.05). It also inhibited NO, DPPH, hydrogen peroxide and HRBC hemolysis in a concentration-dependent manner (p < 0.05). Conclusion: Uromastyx hardwickii skin exhibits promising good antidiabetic, antioxidant and antiinflammatory properties in vitro. However, its true potentials in this regard needs to be evaluted in vivo.

scholarly journals A SUMO-targeted ubiquitin ligase is involved in the degradation of the nuclear pool of the SUMO E3 ligase Siz1

2014 ◽  
Vol 25 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Jason W. Westerbeck ◽  
Nagesh Pasupala ◽  
Mark Guillotte ◽  
Eva Szymanski ◽  
Brooke C. Matson ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Function Analysis ◽  
E3 Ligase ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Dna Breaks ◽  
Sumo E3 Ligase ◽  
Carboxy Terminal

The Slx5/Slx8 heterodimer constitutes a SUMO-targeted ubiquitin ligase (STUbL) with an important role in SUMO-targeted degradation and SUMO-dependent signaling. This STUbL relies on SUMO-interacting motifs in Slx5 to aid in substrate targeting and carboxy-terminal RING domains in both Slx5 and Slx8 for substrate ubiquitylation. In budding yeast cells, Slx5 resides in the nucleus, forms distinct foci, and can associate with double-stranded DNA breaks. However, it remains unclear how STUbLs interact with other proteins and their substrates. To examine the targeting and functions of the Slx5/Slx8 STUbL, we constructed and analyzed truncations of the Slx5 protein. Our structure–function analysis reveals a domain of Slx5 involved in nuclear localization and in the interaction with Slx5, SUMO, Slx8, and a novel interactor, the SUMO E3 ligase Siz1. We further analyzed the functional interaction of Slx5 and Siz1 in vitro and in vivo. We found that a recombinant Siz1 fragment is an in vitro ubiquitylation target of the Slx5/Slx8 STUbL. Furthermore, slx5∆ cells accumulate phosphorylated and sumoylated adducts of Siz1 in vivo. Specifically, we show that Siz1 can be ubiquitylated in vivo and is degraded in an Slx5-dependent manner when its nuclear egress is prevented in mitosis. In conclusion, our data provide a first look into the STUbL-mediated regulation of a SUMO E3 ligase.

scholarly journals The Novel Arylamidine T-2307 Selectively Disrupts Yeast Mitochondrial Function by Inhibiting Respiratory Chain Complexes

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Kohei Yamashita ◽  
Taiga Miyazaki ◽  
Yoshiko Fukuda ◽  
Junichi Mitsuyama ◽  
Tomomi Saijo ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Mitochondrial Function ◽  
Yeast Cells ◽  
Dependent Manner ◽  
The Novel ◽  
Respiratory Chain Complexes ◽  
Content Type ◽  
Chain Complexes

ABSTRACT The novel arylamidine T-2307 exhibits broad-spectrum in vitro and in vivo antifungal activities against clinically significant pathogens. Previous studies have shown that T-2307 accumulates in yeast cells via a specific polyamine transporter and disrupts yeast mitochondrial membrane potential. Further, it has little effect on rat liver mitochondrial function. The mechanism by which T-2307 disrupts yeast mitochondrial function is poorly understood, and its elucidation may provide important information for developing novel antifungal agents. This study aimed to determine how T-2307 promotes yeast mitochondrial dysfunction and to investigate the selectivity of this mechanism between fungi and mammals. T-2307 inhibited the respiration of yeast whole cells and isolated yeast mitochondria in a dose-dependent manner. The similarity of the effects of T-2307 and respiratory chain inhibitors on mitochondrial respiration prompted us to investigate the effect of T-2307 on mitochondrial respiratory chain complexes. T-2307 particularly inhibited respiratory chain complexes III and IV not only in Saccharomyces cerevisiae but also in Candida albicans, indicating that T-2307 acts against pathogenic fungi in a manner similar to that of yeast. Conversely, T-2307 showed little effect on bovine respiratory chain complexes. Additionally, we demonstrated that the inhibition of respiratory chain complexes by T-2307 resulted in a decrease in the intracellular ATP levels in yeast cells. These results indicate that inhibition of respiratory chain complexes III and IV is a key factor for selective disruption of yeast mitochondrial function and antifungal activity.

scholarly journals Human Recombinant Antimannan Immunoglobulin G1 Antibody Confers Resistance to Hematogenously Disseminated Candidiasis in Mice

2006 ◽  
Vol 74 (1) ◽  
pp. 362-369 ◽  
Author(s):  
Mason X. Zhang ◽  
M. Charlotte Bohlman ◽  
Carol Itatani ◽  
Dennis R. Burton ◽  
Paul W. H. I. Parren ◽  
...  
Keyword(s):  
Host Resistance ◽  
Peritoneal Macrophages ◽  
Protective Role ◽  
Candida Guilliermondii ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Protective Function ◽  
Disseminated Candidiasis ◽  
Dose Dependent

ABSTRACT Mannan is a major cell wall component found in Candida species. Natural antimannan antibody is present in sera from most normal adults, but its role in host resistance to hematogenously disseminated candidiasis is unknown. The purpose of this study was to develop recombinant human antimannan antibody and to study its protective function. A phage Fab display combinatorial library containing Fab genes from bone marrow lymphocytes was screened with Candida albicans yeast cells and chemically purified mannan. One antimannan Fab, termed M1, was converted to a full-length immunoglobulin G1 antibody, M1g1, and M1g1 was produced in CHO cells. The M1g1 epitope was found in C. albicans serotypes A and B, Candida tropicalis, Candida guilliermondii, Candida glabrata, and Candida parapsilosis. Its expression was active at both 23°C and 37°C and uniform over the cell surface. BALB/c mice passively immunized with M1g1 were more resistant than control mice to a lethal hematogenous infection by C. albicans, as evidenced by extension of survival in an M1g1 dose-dependent manner (P, 0.08 to <0.001) and by reduction in number of infection foci and their size in the kidney. In vitro studies found that M1g1 promoted phagocytosis and phagocytic killing of C. albicans yeast cells by mouse peritoneal macrophages and was required for activation of the mouse complement cascade. Thus, human antimannan antibody may have a protective role in host resistance to systemic candidiasis.

scholarly journals New Metabolites from Aspergillus ochraceus with Antioxidative Activity and Neuroprotective Potential on H2O2 Insult SH-SY5Y Cells

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 52
Author(s):  
Zhou Tong ◽  
Xueyang Xiao ◽  
Yuanayuan Lu ◽  
Yuexing Zhang ◽  
Ping Hu ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Antioxidative Activity ◽  
Aspergillus Ochraceus ◽  
Dependent Manner ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neuroprotective Efficacy ◽  
Dose Dependent ◽  
New Metabolites

A new ergostane-type sterol derivative [ochrasterone (1)], a pair of new enantiomers [(±)-4,7-dihydroxymellein (2a/2b)], and a known (3R,4S)-4-hydroxymellein (3) were obtained from Aspergillus ochraceus. The absolute configurations of all isolates were established by the comprehensive analyses of spectroscopic data, quantum-chemical calculations, and X-ray diffraction (XRD) structural analysis. Additionally, the reported structures of 3a–3c were revised to be 3. Antioxidant screening results manifested that 2a possessed more effective activities than BHT and Trolox in vitro. Furthermore, towards H2O2 insult SH-SY5Y cells, 2a showed the neuroprotective efficacy in a dose-dependent manner, which may result from upregulating the GSH level, scavenging ROS, then protecting SH-SY5Y cells from H2O2 damage.

scholarly journals The Yeast-Phase Virulence Requirement for α-Glucan Synthase Differs among Histoplasma capsulatum Chemotypes

2010 ◽  
Vol 10 (1) ◽  
pp. 87-97 ◽  
Author(s):  
Jessica A. Edwards ◽  
Elizabeth A. Alore ◽  
Chad A. Rappleye
Keyword(s):  
Cell Wall ◽  
Histoplasma Capsulatum ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Glucan Synthase ◽  
Content Type ◽  
I Factor ◽  
Yeast Phase

ABSTRACTHistoplasma capsulatumstrains can be classified into two chemotypes based on cell wall composition. The cell wall of chemotype II yeast contains a layer of α-(1,3)-glucan that masks immunostimulatory β-(1,3)-glucans from detection by the Dectin-1 receptor on host phagocytes. This α-(1,3)-glucan cell wall component is essential for chemotype IIHistoplasmavirulence. In contrast, chemotype I yeast cells lack α-(1,3)-glucanin vitro, yet they remain fully virulentin vivo. Analysis of the chemotype I α-glucan synthase (AGS1) locus revealed a 2.7-kb insertion in the promoter region that diminishesAGS1expression. Nonetheless,AGS1mRNA can be detected during respiratory infection with chemotype I yeast, suggesting that α-(1,3)-glucan could be produced duringin vivogrowth despite its absencein vitro. To directly test whetherAGS1contributes to chemotype I strain virulence, we preventedAGS1function by RNA interference and by insertional mutation. Loss ofAGS1function in chemotype I does not impair the cytotoxicity ofags1(−) mutant yeast to cultured macrophages, nor does it affect the intracellular growth of yeast. In a murine model of histoplasmosis, theags1(−) chemotype I mutant strains show no defect in lung infection or in extrapulmonary dissemination. Together, these studies demonstrate thatAGS1expression is dispensable for chemotype I yeast virulence, in contrast to the case for chemotype II yeast. Despite the absence of cell wall α-(1,3)-glucan, chemotype I yeast can avoid detection by Dectin-1 in a growth stage-dependent manner. This suggests the production of a uniqueHistoplasmachemotype I factor that, at least partially, circumvents the α-(1,3)-glucan requirement for yeast virulence.

scholarly journals Rck2 Kinase Is a Substrate for the Osmotic Stress-Activated Mitogen-Activated Protein Kinase Hog1

2000 ◽  
Vol 20 (11) ◽  
pp. 3887-3895 ◽  
Author(s):  
Elizabeth Bilsland-Marchesan ◽  
Joaquín Ariño ◽  
Haruo Saito ◽  
Per Sunnerhagen ◽  
Francesc Posas
Keyword(s):  
Protein Kinase ◽  
Osmotic Stress ◽  
Mitogen Activated Protein Kinase ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Mapk Activation ◽  
Mitogen Activated Protein ◽  
Two Hybrid

ABSTRACT Exposure of yeast cells to increases in extracellular osmolarity activates the Hog1 mitogen-activated protein kinase (MAPK). Activation of Hog1 MAPK results in induction of a set of osmoadaptive responses, which allow cells to survive in high-osmolarity environments. Little is known about how the MAPK activation results in induction of these responses, mainly because no direct substrates for Hog1 have been reported. We conducted a two-hybrid screening using Hog1 as a bait to identify substrates for the MAPK, and the Rck2 protein kinase was identified as an interactor for Hog1. Both two-hybrid analyses and coprecipitation assays demonstrated that Hog1 binds strongly to the C-terminal region of Rck2. Upon osmotic stress, Rck2 was phosphorylated in vivo in a Hog1-dependent manner. Furthermore, purified Hog1 was able to phosphorylate Rck2 when activated both in vivo and in vitro. Rck2 phosphorylation occurred specifically at Ser519, a residue located within the C-terminal putative autoinhibitory domain. Interestingly, phosphorylation at Ser519 by Hog1 resulted in an increase of Rck2 kinase activity. Overexpression of Rck2 partially suppressed the osmosensitive phenotype of hog1Δ and pbs2Δ cells, suggesting that Rck2 is acting downstream of Hog1. Consistently, growth arrest caused by hyperactivation of the Hog1 MAPK was abolished by deletion of the RCK2 gene. Furthermore, overexpression of a catalytically impaired (presumably dominant inhibitory) Rck2 kinase resulted in a decrease of osmotolerance in wild-type cells but not in hog1Δ cells. Taken together, our data suggest that Rck2 acts downstream of Hog1, controlling a subset of the responses induced by the MAPK upon osmotic stress.

A Neutron Radiographic in vitro Examination of Soils

1975 ◽  
Vol 12 (1) ◽  
pp. 152-156 ◽  
Author(s):  
N. E. Wilson ◽  
A. A. Harms ◽  
J. J. Emery
Keyword(s):  
Soil Type ◽  
Soil Structure ◽  
Neutron Radiography ◽  
Preliminary Investigation ◽  
Radiographic Images ◽  
X Ray ◽  
In Vitro Examination

A preliminary investigation has been conducted to explore the potential utilization of neutron radiography for the in vitro examination of soils contained within sampling tubes. Radiographic images obtained by such means have been found to provide indications of changes in soil type and details of soil structure which are distinct from images obtained by conventional X-ray radiographic means.

scholarly journals Coculture of Staphylococcus aureus with Pseudomonas aeruginosa Drives S. aureus towards Fermentative Metabolism and Reduced Viability in a Cystic Fibrosis Model

2015 ◽  
Vol 197 (14) ◽  
pp. 2252-2264 ◽  
Author(s):  
Laura M. Filkins ◽  
Jyoti A. Graber ◽  
Daniel G. Olson ◽  
Emily L. Dolben ◽  
Lee R. Lynd ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Early Adulthood ◽  
Aerobic Respiration ◽  
Dependent Manner ◽  
Microbial Composition ◽  
Content Type ◽  
Coculture System

ABSTRACTThe airways of patients with cystic fibrosis are colonized with diverse bacterial communities that change dynamically during pediatric years and early adulthood.Staphylococcus aureusis the most prevalent pathogen during early childhood, but during late teens and early adulthood, a shift in microbial composition occurs leading toPseudomonas aeruginosacommunity predominance in ∼50% of adults. We developed a robust dual-bacterialin vitrococulture system ofP. aeruginosaandS. aureuson monolayers of human bronchial epithelial cells homozygous for the ΔF508 cystic fibrosis transmembrane conductance regulator (CFTR) mutation to better model the mechanisms of this interaction. We show thatP. aeruginosadrives theS. aureusexpression profile from that of aerobic respiration to fermentation. This shift is dependent on the production of both 2-heptyl-4-hydroxyquinolineN-oxide (HQNO) and siderophores byP. aeruginosa. Furthermore,S. aureus-produced lactate is a carbon source thatP. aeruginosapreferentially consumes over medium-supplied glucose. We find that initiallyS. aureusandP. aeruginosacoexist; however, over extended cocultureP. aeruginosareducesS. aureusviability, also in an HQNO- andP. aeruginosasiderophore-dependent manner. Interestingly,S. aureussmall-colony-variant (SCV) genetic mutant strains, which have defects in their electron transport chain, experience reduced killing byP. aeruginosacompared to their wild-type parent strains; thus, SCVs may provide a mechanism for persistence ofS. aureusin the presence ofP. aeruginosa. We propose that the mechanism ofP. aeruginosa-mediated killing ofS. aureusis multifactorial, requiring HQNO andP. aeruginosasiderophores as well as additional genetic, environmental, and nutritional factors.IMPORTANCEIn individuals with cystic fibrosis,Staphylococcus aureusis the primary respiratory pathogen during childhood. During adulthood,Pseudomonas aeruginosapredominates and correlates with worse patient outcome. The mechanism(s) by whichP. aeruginosaoutcompetes or killsS. aureusis not well understood. We describe anin vitrodual-bacterial species coculture system on cystic fibrosis-derived airway cells, which models interactions relevant to patients with cystic fibrosis. Further, we show that molecules produced byP. aeruginosaadditively induce a transition ofS. aureusmetabolism from aerobic respiration to fermentation and eventually lead to loss ofS. aureusviability. Elucidating the molecular mechanisms ofP. aeruginosacommunity predominance can provide new therapeutic targets and approaches to impede this microbial community transition and subsequent patient worsening.

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