scholarly journals Understanding Stress Response to High-Arsenic Gold-Bearing Sulfide Concentrate in Extremely Metal-Resistant Acidophile Sulfobacillus thermotolerans

2020 ◽  
Vol 8 (7) ◽  
pp. 1076 ◽  
Author(s):  
Anna Panyushkina ◽  
Daria Matyushkina ◽  
Olga Pobeguts
Keyword(s):  
Stress Response ◽  
Microbial Communities ◽  
Molecular Mechanisms ◽  
Raw Materials ◽  
Metal Resistance ◽  
Sulfide Ore ◽  
Microbial Responses ◽  
Sulfide Concentrate ◽  
High Arsenic ◽  
Gold Bearing

Biooxidation of gold-bearing arsenopyrite concentrates, using acidophilic microbial communities, is among the largest commercial biohydrometallurgical processes. However, molecular mechanisms of microbial responses to sulfide raw materials have not been widely studied. The goal of this research was to gain insight into the defense strategies of the acidophilic bacterium Sulfobacillus thermotolerans, which dominates microbial communities functioning in industrial biooxidation processes at >35 °C, against the toxic effect of the high-arsenic gold-bearing sulfide concentrate. In addition to extreme metal resistance, this acidophile proved to be one of the most As-tolerant microorganisms. Comparative proteomic analysis indicated that 30 out of 33 differentially expressed proteins were upregulated in response to the ore concentrate, while the synthesis level of the functional proteins required for cell survival was not negatively affected. Despite a high level of cellular metal(loid) accumulation, no specific metal(loid)-resistant systems were regulated. Instead, several proteins involved in the metabolic pathways and stress response, including MBL fold metallo-hydrolase, sulfide:quinone oxidoreductase, and GroEL chaperonin, may play crucial roles in resistance to the sulfide ore concentrate and arsenic, in particular. This study provides the first data on the microbial responses to sulfide ore concentrates and advances our understanding of defense mechanisms against toxic compounds in acidophiles.

INFLUENCE OF TEMPERATURE AND CARBON SOURCE ON BIOXIDATION OF PYRITE-ARSENOPYRITE CONCENTRATE

2020 ◽  
pp. 361-363
Author(s):  
A. Nechaeva ◽  
Y. Elkina ◽  
V. Melamud
Keyword(s):  
Carbon Source ◽  
Microbial Communities ◽  
Carbon Sources ◽  
Microbial Populations ◽  
Effect Of Temperature ◽  
Influence Of Temperature ◽  
Carbon Nutrition ◽  
Sulfide Concentrate ◽  
Gold Bearing

The effect of temperature and sources of carbon nutrition on the composition of microbial communities carrying out the biooxidation of gold-bearing sulfide concentrate and on the efficiency of the biooxidation was investigated. It was shown that the use of additional carbon sources makes it possible to influence the activity of the biooxidation process and the composition of microbial populations.

scholarly journals Overexpression of the Apple (Malus× domestica) MdERF100 in Arabidopsis Increases Resistance to Powdery Mildew

2021 ◽  
Vol 22 (11) ◽  
pp. 5713
Author(s):  
Yiping Zhang ◽  
Li Zhang ◽  
Hai Ma ◽  
Yichu Zhang ◽  
Xiuming Zhang ◽  
...  
Keyword(s):  
Stress Response ◽  
Powdery Mildew ◽  
Malus Domestica ◽  
Molecular Mechanisms ◽  
Powdery Mildew Resistance ◽  
Bimolecular Fluorescence Complementation ◽  
Bhlh Protein ◽  
Mildew Resistance ◽  
Sa Signaling

APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factors play important roles in plant development and stress response. Although AP2/ERF genes have been extensively investigated in model plants such as Arabidopsis thaliana, little is known about their role in biotic stress response in perennial fruit tree crops such as apple (Malus × domestica). Here, we investigated the role of MdERF100 in powdery mildew resistance in apple. MdERF100 localized to the nucleus but showed no transcriptional activation activity. The heterologous expression of MdERF100 in Arabidopsis not only enhanced powdery mildew resistance but also increased reactive oxygen species (ROS) accumulation and cell death. Furthermore, MdERF100-overexpressing Arabidopsis plants exhibited differential expressions of genes involved in jasmonic acid (JA) and salicylic acid (SA) signaling when infected with the powdery mildew pathogen. Additionally, yeast two-hybrid and bimolecular fluorescence complementation assays confirmed that MdERF100 physically interacts with the basic helix–loop–helix (bHLH) protein MdbHLH92. These results suggest that MdERF100 mediates powdery mildew resistance by regulating the JA and SA signaling pathways, and MdbHLH92 is involved in plant defense against powdery mildew. Overall, this study enhances our understanding of the role of MdERF genes in disease resistance, and provides novel insights into the molecular mechanisms of powdery mildew resistance in apple.

scholarly journals Impact of Carcinogenic Chromium on the Cellular Response to Proteotoxic Stress

2019 ◽  
Vol 20 (19) ◽  
pp. 4901 ◽  
Author(s):  
Leonardo M. R. Ferreira ◽  
Teresa Cunha-Oliveira ◽  
Margarida C. Sobral ◽  
Patrícia L. Abreu ◽  
Maria Carmen Alpoim ◽  
...  
Keyword(s):  
Stress Response ◽  
Health Effects ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Chemical Properties ◽  
Adverse Health Effects ◽  
Proteotoxic Stress ◽  
Adverse Health ◽  
The Impact

Worldwide, several million workers are employed in the various chromium (Cr) industries. These workers may suffer from a variety of adverse health effects produced by dusts, mists and fumes containing Cr in the hexavalent oxidation state, Cr(VI). Of major importance, occupational exposure to Cr(VI) compounds has been firmly associated with the development of lung cancer. Counterintuitively, Cr(VI) is mostly unreactive towards most biomolecules, including nucleic acids. However, its intracellular reduction produces several species that react extensively with biomolecules. The diversity and chemical versatility of these species add great complexity to the study of the molecular mechanisms underlying Cr(VI) toxicity and carcinogenicity. As a consequence, these mechanisms are still poorly understood, in spite of intensive research efforts. Here, we discuss the impact of Cr(VI) on the stress response—an intricate cellular system against proteotoxic stress which is increasingly viewed as playing a critical role in carcinogenesis. This discussion is preceded by information regarding applications, chemical properties and adverse health effects of Cr(VI). A summary of our current understanding of cancer initiation, promotion and progression is also provided, followed by a brief description of the stress response and its links to cancer and by an overview of potential molecular mechanisms of Cr(VI) carcinogenicity.

Role of water contents on microwave roasting of gold bearing high arsenic sulphide concentrate

2017 ◽  
Vol 161 ◽  
pp. 72-77 ◽  
Author(s):  
Nan Hu ◽  
Wei Chen ◽  
De-xin Ding ◽  
Feng Li ◽  
Zhong-ran Dai ◽  
...  
Keyword(s):  
Microwave Roasting ◽  
Water Contents ◽  
High Arsenic ◽  
Gold Bearing

scholarly journals Early Spring Snowmelt and Summer Droughts Strongly Impair the Resilience of Key Microbial Communities in Subalpine Grassland Ecosystems

2021 ◽  
Author(s):  
Farhan Hafeez ◽  
Lionel Bernard ◽  
Jean-Christophe Clement ◽  
Franck Poly ◽  
Thomas Pommier
Keyword(s):  
Microbial Communities ◽  
Plant Biomass ◽  
Early Spring ◽  
Climatic Extremes ◽  
Soil Microbial ◽  
Cascading Effect ◽  
Growing Seasons ◽  
Grassland Ecosystems ◽  
Microbial Responses ◽  
Early Snowmelt

Subalpine grassland ecosystems are important from biodiversity, agriculture, and touristic perspectives but their resilience to seasonally occurring climatic extremes is increasingly challenged with climate change, accelerating their vulnerability to tipping points. Microbial communities, which are central in ecosystem functioning, are usually considered as more resistant and highly resilient to such extreme events due to their functional redundancy and strong selection in residing habitats. To investigate this, we explored the soil microbial responses upon recurrent summer droughts associated with early snowmelt in grasslands mesocosms set-up at the Lautaret Pass (French Alps). Potential respiration, nitrification and denitrification were monitored over a period of two growing seasons along with quantification of community gene abundances of total bacteria as well as (de)nitrifiers. Results revealed that droughts had a low and short-term impact on bacterial total respiration supporting their hypothesized high resistance and ability to recover. Nitrification and abundances of the corresponding functional guilds showed relatively strong resistance to summer droughts but declined in response to early snowmelt. This triggered a cascading effect on denitrification but also on the abundances of denitrifying communities which could recover from all climatic extremes except from the summer droughts where nitrifiers were collapsed. Denitrification and the respective functional groups faced high impact of applied stresses with strong reduction in the abundance and activity of this specialized community. Although, the consequently lower microbial competition for nitrate may be positive for plant biomass production, warnings exist when considering the potential nitrogen leaching from these ecosystems as well as risks of greenhouses gases emission such as N2O

scholarly journals RNA sequencing reveals metabolic and regulatory changes leading to more robust fermentation performance during short-term adaptation of Saccharomyces cerevisiae to lignocellulosic inhibitors

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Marlous van Dijk ◽  
Peter Rugbjerg ◽  
Yvonne Nygård ◽  
Lisbeth Olsson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Stress Response ◽  
Rna Sequencing ◽  
Molecular Mechanisms ◽  
Lignocellulosic Hydrolysate ◽  
Short Term ◽  
Down Regulation ◽  
Time Resolved ◽  
Second Generation Bioethanol ◽  
Short Term Adaptation

Abstract Background The limited tolerance of Saccharomyces cerevisiae to inhibitors is a major challenge in second-generation bioethanol production, and our understanding of the molecular mechanisms providing tolerance to inhibitor-rich lignocellulosic hydrolysates is incomplete. Short-term adaptation of the yeast in the presence of dilute hydrolysate can improve its robustness and productivity during subsequent fermentation. Results We utilized RNA sequencing to investigate differential gene expression in the industrial yeast strain CR01 during short-term adaptation, mimicking industrial conditions for cell propagation. In this first transcriptomic study of short-term adaption of S. cerevisiae to lignocellulosic hydrolysate, we found that cultures respond by fine-tuned up- and down-regulation of a subset of general stress response genes. Furthermore, time-resolved RNA sequencing allowed for identification of genes that were differentially expressed at 2 or more sampling points, revealing the importance of oxidative stress response, thiamin and biotin biosynthesis. furan-aldehyde reductases and specific drug:H+ antiporters, as well as the down-regulation of certain transporter genes. Conclusions These findings provide a better understanding of the molecular mechanisms governing short-term adaptation of S. cerevisiae to lignocellulosic hydrolysate, and suggest new genetic targets for improving fermentation robustness.

scholarly journals Physiological and transcriptomic analyses reveal the mechanisms underlying the salt tolerance of Zoysia japonica Steud.

2020 ◽  
Author(s):  
Jingjing Wang ◽  
Cong An ◽  
Hailin Guo ◽  
Xiangyang Yang ◽  
Jingbo Chen ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Salt Stress ◽  
Stress Response ◽  
Salt Tolerance ◽  
Molecular Mechanisms ◽  
Salt Tolerant ◽  
Zoysia Japonica ◽  
Salt Stress Response ◽  
Leaves And Roots ◽  
Time Point

Abstract Background: Areas with saline soils are sparsely populated and have fragile ecosystems, which severely restricts the sustainable development of local economies. Zoysia grasses are recognized as excellent warm-season turfgrasses worldwide, with high salt tolerance and superior growth in saline-alkali soils. However, the mechanism underlying the salt tolerance of Zoysia species remains unknown. Results: The phenotypic and physiological responses of two contrasting materials, Zoysia japonica Steud. Z004 (salt sensitive) and Z011 (salt tolerant) in response to salt stress were studied. The results show that Z011 was more salt tolerant than was Z004, with the former presenting greater K+/Na+ ratios in both its leaves and roots. To study the molecular mechanisms underlying salt tolerance further, we compared the transcriptomes of the two materials at different time points (0 h, 1 h, 24 h, and 72 h) and from different tissues (leaves and roots) under salt treatment. The 24-h time point and the roots might make significant contributions to the salt tolerance. Moreover, GO and KEGG analyses of different comparisons revealed that the key DEGs participating in the salt-stress response belonged to the hormone pathway, various TF families and the DUF family. Conclusions: Z011 may have improved salt tolerance by reducing Na+ transport from the roots to the leaves, increasing K+ absorption in the roots and reducing K+ secretion from the leaves to maintain a significantly greater K+/Na+ ratio. Twenty-four hours might be a relatively important time point for the salt-stress response of zoysiagrass. The auxin signal transduction family, ABA signal transduction family, WRKY TF family and bHLH TF family may be the most important families in Zoysia salt-stress regulation. This study provides fundamental information concerning the salt-stress response of Zoysia and improves the understanding of molecular mechanisms in salt-tolerant plants.

scholarly journals The C. elegans Hypertonic Stress Response: Big Insights from Shrinking Worms

2020 ◽  
Vol 55 (S1) ◽  
pp. 89-105
Keyword(s):  
Stress Response ◽  
Cell Volume ◽  
Molecular Mechanisms ◽  
Model Organism ◽  
Future Research ◽  
Transcriptional Level ◽  
Molecular Signaling ◽  
Hypertonic Stress ◽  
Macromolecular Assemblies ◽  
C Elegans

Cell volume is one of the most aggressively defended physiological set points in biology. Changes in intracellular ion and water concentrations, which are induced by changes in metabolism or environmental exposures, disrupt protein folding, enzymatic activity, and macromolecular assemblies. To counter these challenges, cells and organisms have evolved multifaceted, evolutionarily conserved molecular mechanisms to restore cell volume and repair stress induced damage. However, many unanswered questions remain regarding the nature of cell volume 'sensing' as well as the molecular signaling pathways involved in activating physiological response mechanisms. Unbiased genetic screening in the model organism C. elegans is providing new and unexpected insights into these questions, particularly questions relating to the hypertonic stress response (HTSR) pathway. One surprising characteristic of the HTSR pathway in C. elegans is that it is under strong negative regulation by proteins involved in protein homeostasis and the extracellular matrix (ECM). The role of the ECM in particular highlights the importance of studying the HTSR in the context of a live organism where native ECM-tissue associations are preserved. A second novel and recently discovered characteristic is that the HTSR is regulated at the post-transcriptional level. The goal of this review is to describe these discoveries, to provide context for their implications, and to raise outstanding questions to guide future research.

Epithermal gold-bearing sulfide ore deposit Tulallar: Structure, structural geology and mineralization patterns

2021 ◽  
pp. 53-60
Author(s):  
Sh. F. Abdullaeva ◽  
V. M. Baba-zade ◽  
N. A. Imamverdiev ◽  
N. N. Ismailova
Keyword(s):  
Structural Geology ◽  
Epithermal Gold ◽  
Ore Deposit ◽  
Sulfide Ore ◽  
Gold Bearing
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