Biography:

Sanin Musovic, a molecular microbiologist, completed both his PhD (2010) and 5-years postdoctoral studies at Danish Technical University. He is currently Specialist in Microbiology and Bioengineering at Danish Technological Institute, where he leads drinking water laboratory. He serves as: reviewer for 5 international journals, external/invited expert in EU commissions LIF Team, has over 30 publications (peer-reviewed journals and conference proceedings) etc.

Abstract:

Groundwater filtration by rapid sand filters (RSF) at waterworks is a widespread technology for drinking water production, which efficiently removes the naturally occurring pollutants (e.g., NH4) by a combination of chemical and biological (microbial) processes. During the past few decades, unnatural toxic substances, pesticides, have appeared in groundwater, which challenges the future stable supply of drinking water to consumers. The aim of current project was to develop an environmentally friendly biotechnology dealing with pesticides in ground- and drinking water. The biotechnology is based on natural microorganisms in RSF, possessing the abilities to degrade pesticides toward CO2 and H2O. These skills are frequently located on mobile genetic elements (MGE), which bacteria exchange among themselves. Application of natural isolates with pesticide-degrading genes on mobile genetic elements (MGE^P) would ensure transfer and permanent establishment of introduced MGE^P among the native microbial communities. Hence, the Trojan Horse biotechnology`s omits the well-known limitations of low-to-none survival of exogenously introduced pollutant degrading bacteria in the environment.

Results shown that prolonged (½ year) exposure of sand material to investigated pesticides enhanced the fraction of pesticide-degrading bacteria in enrichments, ensuring isolation. Pesticides effected the structure of microbial communities, reducing abundance of e.g. Alpha Proteobacteria and Nitrospira sp by MCPP, or stimulation Springobacteriia sp. by glyphosate.

Suitability of Trojan Horse concept was confirmed by experiments combining plasmid-borne reporter (gfp) gene and flow-cytometric approach, revealing dominance of Alpha-, Beta- and Gamma Proteobacteria among native sand filter bacteria that acquired investigated plasmid (MGE). (Up to 250 words)

Biography:

Mihai Nita-Lazar has a wide expertise in the fields of microbiology, molecular biology and biochemistry mainly developed in prestigious laboratories such as the Institute of Microbiology, ETH, Zurich, Switzerland, the Department of Biochemistry and Cellular Biology of Stony Brook University, New York, SUA, the Department of Cellular and Molecular Biology of Medical University Center from Boston, Massachusetts, SUA and the Department of Microbiology, University of Medicine, Baltimore, Maryland, SUA. He is currently working as principal investigator of Bioassay-Biological Analysis Laboratory of the National R&D Institute for Industrial Ecology-ECOIND. He has more than 40 ISI papers, 4 books/chapters, h-index 10.

Abstract:

The waterborne pathogenic bacteria, especially the enteric bacteria of human fecal origin have become currently a global public health issue. The detection and quantification of drinking water microorganisms are an essential part of any quality control or water safety management plan interconnected to enteric bacterial pathogens such as Salmonella spp., Shigella spp., Fibrio cholerae or to nonfecal bacterial pathogens such as Legionella spp. The standard methods of detecting waterborne pathogenic bacteria are time-consuming due to the growing step in a specific culture media, followed by isolation, microbiological and/or serological identification and in some cases followed by subspecific characterization.

This study aimed to develop a faster, powerful, more sensitive and reproducible diagnostic tool to monitor a specific pathogen contamination in drinking water by specific antibody-antigen interactions. Three pathogenic bacteria such as Pseudomonas aeruginosa, Escherichia coli and Legionella sp. were detected by immunofluoresce technique with fluorochome tagged antibodies. Our results showed a good specificity of the antibodies in a very complex bacterial mixt as well as a starting detection level from 1 bacteria / ml.

Overall, these technique proved to be a reliable one, time-effective and sensitive for diagnosis and prevention of drinking water quality and waterborne bacterial disease.

Biography:

Sanin Musovic, a molecular microbiologist, completed both his PhD (2010) and 5-years postdoctoral studies at Danish Technical University. He is currently Specialist in Microbiology and Bioengineering at Danish Technological Institute, where he leads drinking water laboratory. He serves as: reviewer for 5 international journals, external/invited expert in EU commissions LIF Team, has over 30 publications (peer-reviewed journals and conference proceedings) etc.

Abstract:

Biological rapid sand filters (RSF) are commonly used for drinking water production at waterworks in Denmark, Europe and worldwide. RSF is a place where natural groundwater pollutants (e.g. ammonium) are removed. The native microorganisms in RSFs have an important role in removal of pollutants, where a sudden change in e.g. ammonium removal suggests a misbalance in microbial community. The aim of current work was to get a deeper insight in the physiological needs of main microbial groups at RSF to micronutrients (trace elements). Waterworks frequently receive groundwater with different chemical properties (incl. micronutrients) from distant water-wells, which allows creation of well-defined inlet-water blend.qPCR based approach revealed that sand filters were microbial rich environments, harboring ca. 3 billion bacteria per gram sand. The ammonium oxidizing bacteria (AOB) stayed for 1-3 % of bacterial population. AOB were up to 50-times more abundant in pre-filter units than in respective after-filter units. The abundance of ammonium oxidizing archaea was trivially low, suggesting that AOB stayed for full ammonium removal in RSF. Both the laboratory column-experiments and full-scale trials at waterworks suggested that certain sand filters at a waterworks naturally possessed an extra NH4- removal capacity. A fine blending of inlet water from chosen water-wells, focusing on copper and nickel at low (0.1 – 1.0 ug/L) concentrations, shown a high (>50%) and persistent stimulating effect on NH4 removal by ammonium oxidizing bacteria. A sudden stimulating-effect of nickel and cupper appeared to be product of increased catabolic abilities of the existing AOB cells.

Biography:

Catalina Stoica has completed her PhD in 2016 from University of Bucharest, Ecological Systems and Sustainability Department, Faculty of Biology in Romania. She is currently working as a research scientist in Laboratory of Bioassay-Biological Analysis of the National R&D Institute for Industrial Ecology-ECOIND, the only institute in Romania that displays a global approach on industrial ecology and environmental issues. She has published more than 18 papers both as first author and co-author in international journals as well as three co-authored book chapters.

Abstract:

The human population increase led to agricultural and farming development, which is limited by its land availability. Now a days, a major direction is based on the production efficiency and on the economy of size. The economy of size aims to lower the average cost per unit of production as the production increased. In our study, we used a very abundant and economically efficient nutrient to reduce the feeding costs, but to keep at least the same level of eggs and meat poultry production.The new nutrient formula was based on cellulose fibres, combined to a cellulosic enzymatic food supplement. Our in vitro results showed that by adding a cellulase based compound to the new feeding nutrient the cellulose content decreased, so the poultry could digest the new and economically efficient diet without any duodenal negative impact. In vitro enzyme – substrate assays were performed on 14 cellulose based nutrients (substrates) and 2 cellulase food supplements (enzymes). The results showed a 50% efficiency of cellulose degradation rate during 1h for an 1:1 enzyme-substrate ratio, especially for the Biozym M6000 food supplement. Moreover, the nutrients and the food supliments were microbiologically tested for the presence of Escherichia coli and Salmonella sp. The results showed the absence of Salmonella sp., but the presence of Escherichia coli in a density ranged between 33 and 1609 CFU/ml. Overall, the results showed an economical viable solution for poultry farms based on a rich cellulose based nutrients supplemented with cellulase food supplement.

Biography:

Dr Ajayi obtained his Ph.D. (Microbiology) degree from the University of Ibadan, Ibadan, Nigeria in 2005. I had diversified working and research experience in the field of Environmental Microbiology and Antimicrobials. He published over 50 research articles in learned journals worldwide. His research activity progresses with surveillance of antibiotic resistant reservoirs during Postdoctoral fellowship program in the Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa sponsored by Govan Mbeki Research and Development Center of the institution. He is currently the acting Head of Department of Microbiology, Adekunle Ajasin University, Akungba-Akoko, Nigeria.        

Abstract:

Various types of bacterial isolates were obtained from commonly consumed food sources, viz rice and beans in some Akoko communities, Nigeria and the world at large. The bacterial isolates were identified by standard microbiological methods. Proximate analysis was carried out according to the procedure of association of official Analytical Chemists to determine amount of components such as fat content, protein content, moisture content and ash content in food samples. Bacterial isolates encountered during the study includes Clostridium spp. (4), Vibrio cholera (1), Bacillus spp. (3), Escherichia coli (2), Staphylococcus aureus (2), Shigella spp. (2), Pseudomonas spp. (2), Streptococcus spp. (2), and Micrococcus spp. (6). Proximate analysis determined, shows the values of food components (in percentages, %) for rice and beans as, Moisture content (11.76, 13.96), Ash content (0.68, 2.52), Crude Fat (3.00, 6.65), Crude protein (15.67, 21.58) Crude fibre (1.44, 0.32) and Carbohydrate content (67.45, 54.97). This study helps to investigate field samplings of the staple food studied in that microbes isolated from the commonly consumed food (rice and beans) in this part of Nigeria and world at large, were used as a measure to determine level of contamination and possible microflora that may inhabit these food sources for possible industrial applications. Similarly, the proximate analysis done helps to determine dietary value as well as food safety. Hence, these food sources should be properly handled coupled with appropriate storage based on their nutritional value and liability of contamination at difference stages of their processing from the raw source. 

Biography:

Abstract:

Phenylpropenes (PPs) are volatile hydrophobic phytochemicals generally characterized by their potent antibacterial activities. The modes of antibacterial actions of these molecules differ from those of conventional antibiotics, which suggests their usage may help overcome antibiotic resistance mechanisms.The efficacy of allylic/propenylic PP isomers (eugenol/isoeugenol and estragole/anethole) was evaluated by macrodilution methods allowing to determine IC50s, MICs and MBCs against reference strains, Escherichia coli ATCC 25922 and Staphylococcus epidermidis ATCC 14990. Results indicate that all PPs were efficient against both bacteria in low millimolar levels, which makes them considerably less potent than common antibiotics. Allylic/propenylic isomers presented very similar growth inhibition patterns, indicating that the position of the double bond in the propenyl chain has low influence on PPs efficacy against the studied strains. For both strains, eugenol and isoeugenol were two to three times less effective than anethole and estragole, indicating distinctive modes of actions between these two pairs of isomers. Eugenol and isoeugenol would particularly involve their hydroxyl group to elicit antibacterial activity. Lacking a free hydroxyl group, the mode of action of anethole and estragole may be rather related to their higher lipophilic character. Interestingly, Gram-negative E. coli, showed to be more susceptible to all PPs than the Gram-positive S. epidermidis strain, probably due to the easier permeation of PPs across the hydrophobic cell emvelope structures of E. coli. Using high-dose PPs (low millimiolar levels) in vivo may not be an optimal strategy, however combination of phytochemicals presenting different mechanisms of action may allow reduction of efficient doses.

Biography:

Ayman K. El Essawy has Ph.D in Microbiology, (Ain Shams University, Egypt), a diploma in Hospital Infection Control (Claude Bernard-Lyone 1 University, France) and a Diploma in Biostatistics (Ain Shams University, Egypt). He is fellow of Microbiology at Ain Shams University. He worked at Al Azhar University & American Naval Medical Research Unit No.3 (NAMRU-3) and Ain Shams University Genetic Engineering/biotechnology center. He is publishing mainly in the field of Microbiology and Molecular Microbiology. He is particularly interested in the study of bacterial resistance to antibiotics.  

Abstract:

The authors previously, achieved a high yield of exopolysaccharide production from a marine Klebsiella sp. The aim of the present study is determination of this exopolysaccharide composition and evaluation of its biological activities. The monosaccharide moieties of this exopolysaccharide were determined by complete hydrolysis, qualitative and quantitative paper chromatography of the hydrolysis product. The monosaccharide composition of this exopolysaccharide was galactose 16%, fructose 20%, glucose 32%, fucose 22%, and uronic acid 10%. The biological activities of the native and modified sulfated bacterial exopolysaccharide were investigated. No anticoagulation or fibrinolytic activities were recorded for the sulfated exopolysaccharide, but the native form of exopolysaccharide showed both activities. The native exopolysaccharide also showed higher antibacterial activity against S. aureus and E. coli but both the native and sulfated form had no antifungal activity against Candida albicans. MIC of the native and sulfated exopolysaccharide that sustain the highest bacterial inhibition zone was 15 mg/dl. No prebiotic activities were recorded for both. In conclusion, this biopolymer has significant biological activities and it has two rare monosaccharide moieties with very significant value namely fucose and uronic acid that require further adaptation for practical and industrial application.

Biography:

Iris Yedidia is the Head of the Ornamental Plants and Agricultural Biotechnology Dep. at the Agricultural Research Organization (ARO), Volcani center, Israel. Since 2004, a scientist and a team leader focusing on applying biotechnological tools to improve ornamental bulbs resistance to bacterial pathogens and studying the involvement of natural products in bacterial pathogenesis.

Abstract:

Plants produce diverse array of low molecular-mass compounds, with more than 8,000 phenolics. Phenolic compounds play a pivotal role in plant defence and fitness. Here, we provide an example for interference of plant small molecules (phenolics) with bacterial virulence, via inhibition of the quorum sensing (QS) machinery of the soft rot bacterium P. carotovorum.

Interestingly, biofilm formation and exoenzymes activity were significantly impaired, at compounds concentrations that did not affect bacterial cell growth or membrane integrity. Since biofilm production and exoenzymes are  virulence determinants known to be under the strict control of QS, the effect of specific molecules on QS was studied. Common volatile and soluble  phenolic compounds were tested for their influence on the expression of central QS system and QS controlled genes. The N-acyl-homoserine lactone (AHL) reporter strains (CV026 and pSB401) demonstrated a prominent reduction in the level of QS signal molecules accumulation, following exposure to the compounds. Moreover, infection capabilities were strongly impaired on potato, cabbage and calla-lily; but fully recovered upon external application of AHL. To further confirm interaction of the plant compounds with bacterial QS targets, drug discovery tools were occupied using the SCHRODINGER^® molecular docking suit.  Pectobacterium central QS proeins  ExpI/ExpR were used as targets for salycilic acid and carvacrol (plant phenolics). Finally uisng isothermal calorimetry (ITC), SA and CAR were diectly bound to cloned and purified ExpI, by this, experimentally supporting the computational docking results. True binding of plant derived phenolics to bacterial QS synthase protein as a target was demonstrated.  The importance of plant-bacteria chemical signalling shown here, supports a rising field of research endeavouring interkingdom communication between plants and bacterial pathogens.

Biography:

Dr. Min-Kyu Kwak holds a Ph.D. in School of Biological Sciences, and Institute of Microbiology, Seoul National University, Republic of Korea. He has completed postdoctoral studies from Seoul National University. He has been appointed as a professor in Sungkul University in Korea and as a visiting professor in University of Malaysia in Sabah. He is an editorial board member of Academy of Annals of Clinical Immunology and Microbiology and an organizer of the International Congress on Science and Technology. He has published/prepared more than 22 papers in international and national journals and proceedings, as first author and corresponding author. He also presented 13 kinds of Korea and international patents regarding cyclic dipeptides inhibitory to against multidrug-resistant bacteria, pathogenic fungi, and influenza A virus.    
 

Abstract:

High methylglyoxal content disrupts cell physiology, but mammals have scavengers to prevent glycolytic and mitochondrial dysfunctions. In yeast, methylglyoxal accumulation triggers methylglyoxal-oxidizing alcohol dehydrogenase (Adh1) activity. While methylglyoxal reductases and glyoxalases have been well studied in prokaryotes and eukaryotes, experimental evidence for methylglyoxal dehydrogenase (Mgd) and other catalytic activities of this enzyme affecting glycolysis and the tricarboxylic acid cycle is lacking. A glycine-rich cytoplasmic Mgd protein, designated as Mgd1/Grp2, was isolated from glutathione-depleted Candida albicans. The effects of Mgd1/Grp2 activities on metabolic pathophysiology were investigated using knockout and overexpression mutants. We measured glutathione-(in)dependent metabolite contents and metabolic effects, including viability, oxygen consumption, ADH1 transcripts, and glutathione reductase and α-ketoglutarate dehydrogenase activities in the mutants. Based on the findings, methylglyoxal-oxidizing proteins were monitored to determine effects of MGD1/GRP2 disruption on methylglyoxal-scavenging traits during glutathione deprivation. Methylglyoxal-oxidizing NAD(H)-linked Mgd1/Grp2 was found solely in glutathione auxotrophs, and it catalyzed the reduction of both methylglyoxal and pyruvate. MGD1/GRP2 disruptants showed growth defects, cell-cycle arrest, and methylglyoxal and pyruvate accumulation with mitochondrial impairment, regardless of ADH1 compensation. Other methylglyoxal-oxidizing enzymes were identified as key glycolytic enzymes with enhanced activity and transcription in MGD1/GRP2 disruptants, irrespective of glutathione content. Failure of methylglyoxal and pyruvate dissimilation by Mgd1/Grp2 deficiency leads to poor glutathione-dependent redox regulation despite compensation by Adh1. This is the first report that multifunctional Mgd activities contribute to scavenging methylglyoxal and pyruvate to maintain metabolic homeostasis and the redox pool via glycolytic enzymes and Adh1 expression.

Biography:

Sergio Giannattasio has completed his studies in Chemistry from Universtity of Bari, Italy in 1982. He is Senior Scientist at the Institute of Biomebranes, Bioenergetics and Molecular Biotechnlogies of CNR in Bari. In 2014 he has been awarded with the qualification as full professor in Applied Biology. He has published 66 papers in reputed JCR journals with 1586 citations and h-index 24 (Google Scholar) and has been serving as an editorial board member of repute. His research interests are mitochondria-to-nucleus cross-talk in cell stress response and the role in tumorigenesis of oncosupressor BRCA2 using yeast Saccharomyces cerevisiae as a model.            

Abstract:

More than 70% of prostate cancer (PCa) patients display loss or reduction of BRCA2 protein, an oncosupressor involved in DNA repair through homologous recombination. We have shown that loss of BRCA2 confers cells resistance to anoikis, a peculiar form of programmed cell death (PCD) necessary for cancer cells to colonize distal sites during the metastatic process. This PCD-promoting function of BRCA2 is conserved in the yeast Saccharomyces cerevisiae. Patients with metastatic PCa display only temporary disease control following androgen deprivation but they eventually develop disease progression to virtually incurable castration-resistant prostate cancer (CRPC). We used yeast expressing BRCA2, normal prostate cell and a CRPC cell line model for a pre-clinical toxicity screening of 6-thioguanine (6-TG) and six 6-TG analogues. We found that 6-TG decreased proliferation in yeast preferably in the presence of BRCA2 and normal prostate cells without inducing cell death. Strikingly, 6-TG not only impaired cell proliferation but also induced significant cell death in CRPC cells by activating a PCD program. Silencing of BRCA2 expression increased CPRC cell sensitivity to 6-TG-induced cell death. 2,6-dithiopurine (2,6DTP) strongly decreased proliferation and induced cell death in yeast independently of BRCA2. 2,6DTP and 2-amino-6-bromopurine selectively induced PCD in BRCA2-expressing CPRC cells. These results suggest the potential use of 6-TG and its analogues for the treatment of CRPC alone or in combination with taxanes, chemotherapeutic drugs approved for CRPC treatment. Acknowledgments: This work was supported by FCRP “Identificazione di molecole attive per lo sviluppo di nuovi farmaci anti-tumorali contro il carcinoma di prostata”.

Biography:

Xiaoling is a full professor of School of Mechanical Engineering at USTB, and a visiting scholar of School of Engineering and Applied Science at Harvard University. She received her BS and MS degrees in Solid Mechanics from Beijing Institute of Technology in 2000 and 2003, and a PhD degree in mechanical engineering from The Hong Kong University of Science and Technology in 2006. She was an postdoctoral fellow at The Hong Kong University from 2006 to 2007, and moved to USTB in 2008. she was a visiting scholar in the Northwestern University of USA. Her research interests focus on Biomechanics, Phase Transitions in bio system, Bacterial biofilms.

Abstract:

We develop an optical imaging technique for spatially and temporally tracking biofilm growth and the distribution of the main phenotypes of a Bacillus subtilis strain with a triple-fluorescent reporter for motility, matrix production, and sporulation. We develop a calibration procedure for determining the biofilm thickness from the transmission images, which is based on Beer-Lambert’s law and involves cross-sectioning of biofilms. To obtain the phenotype distribution, we assume a linear relationship between the number of cells and their fluorescence and determine the best combination of calibration coefficients that matches the total number of cells for all three phenotypes and with the total number of cells from the transmission images. Based on this analysis, we resolve the composition of the biofilm in terms of motile, matrix-producing, sporulating cells and low-fluorescent materials which includes matrix and cells that are dead or have low fluorescent gene expression. We take advantage of the circular growth to make kymograph plots of all three phenotypes and the dominant phenotype in terms of radial distance and time. To visualize the nonlocal character of biofilm growth, we also make kymographs using the local colonization time. Our technique is suitable for real-time, noninvasive, quantitative studies of the growth and phenotype distribution of biofilms which are either exposed to different conditions such as biocides, nutrient depletion, dehydration, or waste accumulation.

Biography:

Grettel Aviles is currently a graduate student in agricultural science at the Universidad Veracruzana, México.
 

Abstract:

The toxicity of nickel and vanadium, potentially toxic elements (PTE), in higher organisms has been widely documented because of its impact on crops or human health, however, toxicity in microorganisms has been poorly studied. The objective of this work is to determine the toxicity of nickel and vanadium in the growth of four strains of plant growth promoting microorganisms. Strains of Candida orthopsilosis B20, Serratia marcescens C753, Pseudomona tolasii P61 and Rhizobium tropici Ciat889 were inoculated into a minimal salt medium at pH of 6.5 at increasing concentrations of VOSO4 (0, 15, 30 and 45 mg · L-1) and NiSO 4 (0, 25, 50 and 75 mg · L-1). They were shaken at 140 rpm at 28 ± 2 ° C for 5 days. Their growth kinetics were measured by the turbidity method in a microplate spectrophotometer. Every 12 h, 200 μl of each sample was taken in triplicate and read at 600 nm, until 120 h. The data were processed by ANOVA, and Tukey's mean comparison test (α = 0.05), with the SAS program for Windows 9.0. The growth of C. orthopsilosis B20 was severely affected by the presence of the two metals, R. tropici Ciat889 was highly sensitive to nickel in all concentrations, while in vanadium, in its lower concentration, it promoted its growth. Both strains of S. marcescens C753 and P. tolasii P61 showed tolerance to PTE and their growth was promoted in low concentrations.

Biography:

Nadeem Hafeez from Lahore, Pakistan. Currently, I am working as Researcher at Center for Excellence in Molecular Biology (CEMB), Lahore, Pakistan. I have expertise in gene editing, cloning and plant transformation; I have developed a first triple gene genetically engineered cotton variety of Pakistan, which confers significant resistance against biotic and abiotic stresses. I have utilized E.coli and yeast expression models to screen mutated genes before transformation in plants. I am currently doing a research project in abiotic tolerance of cotton to learn more about reverse genetics. In this project we are using CRISPR cas9 genome editing to study genes associated with abiotic stress tolerance.

Abstract:

Cotton is a cash crop of Pakistan and Gossypium arboreum is a locally cultivated variety, which has considerable resistance against various biotic and abiotic stresses. This variety of cotton is considered as good reservoir of stress tolerance genes, while based on EST data mostly of its genes are uncharacterized. Universal stress protein-2 (USP-2) gene was identified in 15 days drought stressed leaves of G.arboreum-FDH-171. Full length of this gene was mutated at three different (M₁usp-2, M₂usp-2, M₃usp-2) positions (fig: 1) in three separate clones in E.coli-uspABC-mutant and Pichia pastoris-gs115 strains for its functional validation under various abiotic stress treatments (NaCl 800mM, PEG 8%, Heat 37-45⁰C, Cold 4⁰C). The expression of 1^st mutant (M₁usp-2) was noted as 8.3fold under NaCl stress and 9.7fold under PEG stress treatments, recombinant cells showed higher growth up to 10^-5 dilution in spot assay as compared to control and other genes. The 2^nd mutant form of USP-2 was expressed on induction but it was failed to initiate stress tolerant mechanism in both organisms. No significant difference was noted in between 3^rd mutant form and wild type USP-2. However, all mutant forms showed little tolerance against heat and cold stresses. The results of this study showed that activity of USP-2 was enhanced in M₁usp-2 by enhancing its ATP binding capacity at 2X but wipe out in M₂usp-2 with zero ATP-binding ability and 4X enhanced CMP capacity has no effect on activity of M3-usp-2. In silico analysis showed that 1^st and 3^rd mutant forms of USP-2 may directly involved in stress adaptive mechanism or it might be function as a signaling molecule to initiate stress mechanism.