scholarly journals Two Phytoplasmas Elicit Different Responses in the Insect VectorEuscelidius variegatusKirschbaum

2018 ◽  
Vol 86 (5) ◽  
Author(s):  
Luciana Galetto ◽  
Simona Abbà ◽  
Marika Rossi ◽  
Marta Vallino ◽  
Massimo Pesando ◽  
...  
Keyword(s):  
Immune Response ◽  
Energy Metabolism ◽  
Pathogenic Bacteria ◽  
De Novo ◽  
Transcriptome Assembly ◽  
Content Type ◽  
Flavescence Dorée ◽  
Starting Point ◽  
Potential Pathogen ◽  
Insect Fitness

ABSTRACTPhytoplasmas are plant-pathogenic bacteria transmitted by hemipteran insects. The leafhopperEuscelidius variegatusis a natural vector of chrysanthemum yellows phytoplasma (CYp) and a laboratory vector of flavescence dorée phytoplasma (FDp). The two phytoplasmas induce different effects on this species: CYp slightly improves whereas FDp negatively affects insect fitness. To investigate the molecular bases of these different responses, transcriptome sequencing (RNA-seq) analysis ofE. variegatusinfected with either CYp or FDp was performed. The sequencing provided the firstde novotranscriptome assembly for a phytoplasma vector and a starting point for further analyses on differentially regulated genes, mainly related to immune system and energy metabolism. Insect phenoloxidase activity, immunocompetence, and body pigmentation were measured to investigate the immune response, while respiration and movement rates were quantified to confirm the effects on energy metabolism. The activation of the insect immune response upon infection with FDp, which is not naturally transmitted byE. variegatus, confirmed that this bacterium is mostly perceived as a potential pathogen. Conversely, the acquisition of CYp, which is naturally transmitted byE. variegatus, seems to increase the insect fitness by inducing a prompt response to stress. This long-term relationship is likely to improve survival and dispersal of the infected insect, thus enhancing the opportunity of phytoplasma transmission.

scholarly journals A Plant Bacterial Pathogen Manipulates Its Insect Vector's Energy Metabolism

2016 ◽  
Vol 83 (5) ◽  
Author(s):  
Nabil Killiny ◽  
Faraj Hijaz ◽  
Timothy A. Ebert ◽  
Michael E. Rogers
Keyword(s):  
Energy Metabolism ◽  
Life Span ◽  
Pathogenic Bacteria ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Hunger Level ◽  
Content Type ◽  
Plant Pathogenic Bacteria ◽  
Liberibacter Asiaticus ◽  
Insect Transmission

ABSTRACT Insect-transmitted plant-pathogenic bacteria may alter their vectors' fitness, survival, behavior, and metabolism. Because these pathogens interact with their vectors on the cellular and organismal levels, potential changes at the biochemical level might occur. “Candidatus Liberibacter asiaticus” (CLas) is transmitted in a persistent, circulative, and propagative manner. The genome of CLas revealed the presence of an ATP translocase that mediates the uptake of ATP and other nucleotides from medium to achieve its biological processes, such as growth and multiplication. Here, we showed that the levels of ATP and many other nucleotides were significantly higher in CLas-infected than healthy psyllids. Gene expression analysis showed upregulation for ATP synthase subunits, while ATPase enzyme activity showed a decrease in ATPase activity. These results indicated that CLas stimulated Diaphorina citri to produce more ATP and many other energetic nucleotides, while it may inhibit their consumption by the insect. As a result of ATP accumulation, the adenylated energy charge (AEC) increased and the AMP/ATP and ADP/ATP ratios decreased in CLas-infected D. citri psyllids. Survival analysis confirmed a shorter life span for CLas-infected D. citri psyllids. In addition, electropenetrography showed a significant reduction in total nonprobing time, salivation time, and time from the last E2 (phloem ingestion) to the end of recording, indicating that CLas-infected psyllids were at a higher hunger level and they tended to forage more often. This increased feeding activity reflects the CLas-induced energetic stress. In conclusion, CLas alters the energy metabolism of its psyllid vector, D. citri, in order to secure its need for energetic nucleotides. IMPORTANCE Insect transmission of plant-pathogenic bacteria involves propagation and circulation of the bacteria within their vectors. The transmission process is complex and requires specific interactions at the molecular and biochemical levels. The growth of the plant-pathogenic bacteria in the hemolymph of their vectors indicated that the hemolymph contains all the necessary nutrients for their growth. In addition to nutrients, “Candidatus Liberibacter asiaticus” (CLas) can take up energetic nucleotides, such as ATP, from its vector, Diaphorina citri, using ATP translocase. In this study, we found that the CLas pathogen manipulates the energy metabolism of its insect vector. The accumulation of ATP in CLas-infected D. citri psyllids indicated that CLas induces ATP production to fulfill its need for this energetic compound. As a result of ATP accumulation, a shorter life span and altered feeding behavior were observed. These findings increase our knowledge of insect transmission of the persistent-circulative-propagative type of plant pathogens vectored by insects.

scholarly journals Nitric Oxide Levels Regulate the Immune Response of Drosophila melanogaster Reference Laboratory Strains to Bacterial Infections

2014 ◽  
Vol 82 (10) ◽  
pp. 4169-4181 ◽  
Author(s):  
Ioannis Eleftherianos ◽  
Kareen More ◽  
Stephanie Spivack ◽  
Ethan Paulin ◽  
Arman Khojandi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Immune Response ◽  
Drosophila Melanogaster ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Micrococcus Luteus ◽  
The Other ◽  
Reference Laboratory ◽  
Content Type ◽  
Reference Strains

ABSTRACTStudies on the innate immune response against microbial infections inDrosophila melanogasterinvolve mutant strains and their reference strains that act as experimental controls. We used five standardD. melanogasterlaboratory reference strains (Oregon R, w1118, Canton-S, Cinnabar Brown, and Yellow White [YW]) and investigated their response against two pathogenic bacteria (Photorhabdus luminescensandEnterococcus faecalis) and two nonpathogenic bacteria (Escherichia coliandMicrococcus luteus). We detected high sensitivity among YW flies to bacterial infections and increased bacterial growth compared to the other strains. We also found variation in the transcription of certain antimicrobial peptide genes among strains, with Oregon and YW infected flies showing the highest and lowest gene transcription levels in most cases. We show that Oregon and w1118 flies possess more circulating hemocytes and higher levels of phenoloxidase activity than the other strains upon infection with the nonpathogenic bacteria. We further observed reduced fat accumulation in YW flies infected with the pathogenic bacteria, which suggests a possible decline in physiological condition. Finally, we found that nitrite levels are significantly lower in infected and uninfected YW flies compared to w1118 flies and that nitric oxide synthase mutant flies in YW background are more susceptible to bacterial infection compared to mutants in w1118 background. Therefore, increased sensitivity of YW flies to bacterial infections can be partly attributed to lower levels of nitric oxide. Such studies will significantly contribute toward a better understanding of the genetic variation betweenD. melanogaster reference strains.

scholarly journals Understanding and Eliminating the Detrimental Effect of Thiamine Deficiency on the Oleaginous Yeast Yarrowia lipolytica

2019 ◽  
Vol 86 (3) ◽  
Author(s):  
Caleb Walker ◽  
Seunghyun Ryu ◽  
Richard J. Giannone ◽  
Sergio Garcia ◽  
Cong T. Trinh
Keyword(s):  
Energy Metabolism ◽  
Yarrowia Lipolytica ◽  
Thiamine Deficiency ◽  
Oleaginous Yeast ◽  
De Novo ◽  
Lipid Production ◽  
Cellular Metabolism ◽  
Living Cells ◽  
Lipid Biosynthesis ◽  
Content Type

ABSTRACT Thiamine is a vitamin that functions as a cofactor for key enzymes in carbon and energy metabolism in all living cells. While most plants, fungi, and bacteria can synthesize thiamine de novo, the oleaginous yeast Yarrowia lipolytica cannot. In this study, we used proteomics together with physiological characterization to elucidate key metabolic processes influenced and regulated by thiamine availability and to identify the genetic basis of thiamine auxotrophy in Y. lipolytica. Specifically, we found that thiamine depletion results in decreased protein abundance for the lipid biosynthesis pathway and energy metabolism (i.e., ATP synthase), leading to the negligible growth and poor sugar assimilation observed in our study. Using comparative genomics, we identified the missing 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate synthase (THI13) gene for the de novo thiamine biosynthesis in Y. lipolytica and discovered an exceptional promoter, P3, that exhibits strong activation and tight repression by low and high thiamine concentrations, respectively. Capitalizing on the strength of our thiamine-regulated promoter (P3) to express the missing gene from Saccharomyces cerevisiae (scTHI13), we engineered a thiamine-prototrophic Y. lipolytica strain. By comparing this engineered strain to the wild-type strain, we revealed the tight relationship between thiamine availability and lipid biosynthesis and demonstrated enhanced lipid production with thiamine supplementation in the engineered thiamine-prototrophic Y. lipolytica strain. IMPORTANCE Thiamine plays a crucial role as an essential cofactor for enzymes involved in carbon and energy metabolism in all living cells. Thiamine deficiency has detrimental consequences for cellular health. Yarrowia lipolytica, a nonconventional oleaginous yeast with broad biotechnological applications, is a native thiamine auxotroph whose affected cellular metabolism is not well understood. Therefore, Y. lipolytica is an ideal eukaryotic host for the study of thiamine metabolism, especially because mammalian cells are also thiamine auxotrophic and thiamine deficiency is implicated in several human diseases. This study elucidates the fundamental effects of thiamine deficiency on cellular metabolism in Y. lipolytica and identifies genes and novel thiamine-regulated elements that eliminate thiamine auxotrophy in Y. lipolytica. Furthermore, the discovery of thiamine-regulated elements enables the development of thiamine biosensors with useful applications in synthetic biology and metabolic engineering.

scholarly journals Unique Mode of Cell Division by the Mycobacterial Genetic Resister Clones Emerging De Novo from the Antibiotic-Surviving Population

mSphere ◽  
2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Kishor Jakkala ◽  
Avraneel Paul ◽  
Atul Pradhan ◽  
Rashmi Ravindran Nair ◽  
Deepti Sharan ◽  
...  
Keyword(s):  
Cell Division ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
De Novo ◽  
Bacterial Strains ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Cellular Processes ◽  
Unique Mode

ABSTRACT The emergence of antibiotic genetic resisters of pathogenic bacteria poses a major public health challenge. The mechanism by which bacterial antibiotic genetic resister clones formed de novo multiply and establish a resister population remained unknown. Here, we delineated the unique mode of cell division of the antibiotic genetic resisters of Mycobacterium smegmatis and Mycobacterium tuberculosis formed de novo from the population surviving in the presence of bactericidal concentrations of rifampicin or moxifloxacin. The cells in the rifampicin/moxifloxacin-surviving population generated elevated levels of hydroxyl radical-inflicting mutations. The genetic mutants selected against rifampicin/moxifloxacin became multinucleated and multiseptated and developed multiple constrictions. These cells stochastically divided multiple times, producing sister-daughter cells phenomenally higher in number than what could be expected from their generation time. This caused an abrupt, unexpectedly high increase in the rifampicin/moxifloxacin resister colonies. This unique cell division behavior was not shown by the rifampicin resisters formed naturally in the actively growing cultures. We could detect such abrupt increases in the antibiotic resisters in others’ and our earlier data on the antibiotic-exposed laboratory/clinical M. tuberculosis strains, M. smegmatis and other bacteria in in vitro cultures, infected macrophages/animals, and tuberculosis patients. However, it went unnoticed/unreported in all those studies. This phenomenon occurring in diverse bacteria surviving against different antibiotics revealed the broad significance of the present study. We speculate that the antibiotic-resistant bacillary clones, which emerge in patients with diverse bacterial infections, might be using the same mechanism to establish an antibiotic resister population quickly in the continued presence of antibiotics. IMPORTANCE The bacterial pathogens that are tolerant to antibiotics and survive in the continued presence of antibiotics have the chance to acquire genetically resistant mutations against the antibiotics and emerge de novo as antibiotic resisters. Once the antibiotic resister clone has emerged, often with compromise on growth characteristics, for the protection of the species, it is important to establish an antibiotic-resistant population quickly in the continued presence of the antibiotic. In this regard, the present study has unraveled multinucleation and multiseptation followed by multiple constrictions as the cellular processes used by the bacteria for quick multiplication to establish antibiotic-resistant populations. The study also points out the same phenomenon occurring in other bacterial systems investigated in our laboratory and others’ laboratories. Identification of these specific cellular events involved in quick multiplication offers additional cellular processes that can be targeted in combination with the existing antibiotics’ targets to preempt the emergence of antibiotic-resistant bacterial strains.

scholarly journals Draft Genome Sequence and Annotation of the Lichen-Forming Fungus Arthonia radiata

2018 ◽  
Vol 6 (14) ◽  
Author(s):  
Ellie E. Armstrong ◽  
Stefan Prost ◽  
Damien Ertz ◽  
Martin Westberg ◽  
Andreas Frisch ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Genome Assembly ◽  
Type Species ◽  
De Novo ◽  
Transcriptome Assembly ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Illumina Hiseq ◽  
Content Type ◽  
Mate Pair

ABSTRACT We report here the draft de novo genome assembly, transcriptome assembly, and annotation of the lichen-forming fungus Arthonia radiata (Pers.) Ach., the type species for Arthoniomycetes, a class of lichen-forming, lichenicolous, and saprobic Ascomycota. The genome was assembled using overlapping paired-end and mate pair libraries and sequenced on an Illumina HiSeq 2500 instrument.

scholarly journals Impact of Activation of the Neotrehalosadiamine/Kanosamine Biosynthetic Pathway on the Metabolism of Bacillus subtilis

2021 ◽  
Vol 203 (9) ◽  
Author(s):  
Natsumi Saito ◽  
Huong Minh Nguyen ◽  
Takashi Inaoka
Keyword(s):  
Bacillus Subtilis ◽  
Energy Metabolism ◽  
Biosynthetic Pathway ◽  
De Novo ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Growth Defect ◽  
Metabolome Analysis ◽  
Content Type ◽  
Tca Cycle Intermediates

ABSTRACT The pentose phosphate (PP) pathway is one of the major sources of cellular NADPH. A Bacillus subtilis zwf mutant that lacks glucose-6-phosphate dehydrogenase (the enzyme that catalyzes the first step of the PP pathway) showed inoculum-dose-dependent growth. This growth defect was suppressed by glcP disruption, which causes the upregulation of the autoinducer neotrehalosadiamine (NTD)/kanosamine biosynthetic pathway. A metabolome analysis showed that the stimulation of NTD/kanosamine biosynthesis caused significant accumulation of tricarboxylic acid (TCA) cycle intermediates and NADPH. Because the major malic enzyme YtsJ concomitantly generates NADPH through malate-to-pyruvate conversion, de novo NTD/kanosamine biosynthesis can result in an increase in the intracellular NADPH pool via the accumulation of malate. In fact, a zwf mutant grew in malate-supplemented medium. Artificial induction of glcP in the zwf mutant caused a reduction in the intracellular NADPH pool. Moreover, the correlation between the expression level of the NTD/kanosamine biosynthesis operon ntdABC and the intracellular NADPH pool was confirmed. Our results suggest that NTD/kanosamine has the potential to modulate carbon energy metabolism through an autoinduction mechanism. IMPORTANCE Autoinducers enable bacteria to sense cell density and to coordinate collective behavior. NTD/kanosamine is an autoinducer produced by B. subtilis and several close relatives, although its physiological function remains unknown. The most important finding of this study was the significance of de novo NTD/kanosamine biosynthesis in the modulation of the central carbon metabolism in B. subtilis. We showed that NTD/kanosamine biosynthesis caused an increase in the NADPH pool via the accumulation of TCA cycle intermediates. These results suggest a possible role for NTD/kanosamine in carbon energy metabolism. As Bacillus species are widely used for the industrial production of various useful enzymes and compounds, the NTD/kanosamine biosynthetic pathway might be utilized to control metabolic pathways in these industrial strains.

scholarly journals Protective Immunity against Infection with Mycoplasma haemofelis

2014 ◽  
Vol 22 (1) ◽  
pp. 108-118 ◽  
Author(s):  
Chelsea A. E. Hicks ◽  
Barbara Willi ◽  
Barbara Riond ◽  
Marilisa Novacco ◽  
Marina L. Meli ◽  
...  
Keyword(s):  
Immune Response ◽  
Antibody Response ◽  
Protective Immunity ◽  
De Novo ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mrna Levels ◽  
Immunological Parameters ◽  
Content Type ◽  
Group A ◽  
Group B

ABSTRACTHemoplasmas are potentially zoonotic mycoplasmal pathogens, which are not consistently cleared by antibiotic therapy.Mycoplasma haemofelisis the most pathogenic feline hemoplasma species. The aim of this study was to determine how cats previously infected withM. haemofelisthat had recovered reacted when rechallenged withM. haemofelisand to characterize the immune response followingde novoM. haemofelisinfection and rechallenge. Five specific-pathogen-free (SPF)-derived naive cats (group A) and five cats that had recovered fromM. haemofelisinfection (group B) were inoculated subcutaneously withM. haemofelis. BloodM. haemofelisloads were measured by quantitative PCR (qPCR), antibody response to heat shock protein 70 (DnaK) by enzyme-linked immunosorbent assay (ELISA), blood lymphocyte cell subtypes by flow cytometry, and cytokine mRNA levels by quantitative reverse transcriptase PCR. Group A cats all became infected with high bacterial loads and seroconverted, while group B cats were protected from reinfection, thus providing the unique opportunity to study the immunological parameters associated with this protective immune response againstM. haemofelis. First, a strong humoral response to DnaK was only observed in group A, demonstrating that an antibody response to DnaK is not important for protective immunity. Second, proinflammatory cytokine interleukin-6 (IL-6) mRNA levels appeared to increase rapidly postinoculation in group B, indicating a possible role in protective immunity. Third, an increase in IL-12p35 and -p40 mRNA and decrease in the Th2/Th1 ratio observed in group A suggest that a Th1-type response is important in primary infection. This is the first study to demonstrate protective immunity againstM. haemofelisreinfection, and it provides important information for potential future hemoplasma vaccine design.

scholarly journals Freshwater mussels (Unionidae) brought into captivity exhibit up-regulation of genes involved in stress and energy metabolism

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ieva Roznere ◽  
Brandon T. Sinn ◽  
Marymegan Daly ◽  
G. Thomas Watters
Keyword(s):  
Immune Response ◽  
Energy Metabolism ◽  
De Novo ◽  
Differential Expression Analysis ◽  
Freshwater Mussel ◽  
Gill Tissue ◽  
The United States ◽  
Illumina Hiseq ◽  
Functional Annotations ◽  
Shock Proteins

AbstractApproximately two thirds of freshwater mussel species in the United States and Canada are imperiled, and populations are declining rapidly. Translocation and captive management are commonly used to mitigate losses of freshwater mussel biodiversity, but these conservation tools may result in decreased growth and increased mortality. This study uses RNA-Seq to determine how translocation into captivity affects gene expression in Amblema plicata. Mussels were collected from the Muskingum River in Ohio, USA and brought into a captive holding facility. RNA was extracted from gill tissue 11 months post translocation from mussels in captivity and the Muskingum River on the same day. RNA was sequenced on an Illumina HiSeq 2500, and differential expression analysis was performed on de novo assembled transcripts. More than 1200 transcripts were up-regulated in captive mussels, and 246 were assigned functional annotations. Many up-regulated transcripts were involved in energy metabolism and the stress response, such as heat shock proteins and antioxidants. More than 500 transcripts were down-regulated in captive mussels, and 41 were assigned functional annotations. We observed an over-representation of down-regulated transcripts associated with immune response. Our work suggests that A. plicata experienced moderate levels of stress and altered energy metabolism and immune response for at least 11 months post translocation into captivity.

scholarly journals Th17 Cells in Helicobacter pylori Infection: a Dichotomy of Help and Harm

2019 ◽  
Vol 87 (11) ◽  
Author(s):  
Beverly R. E. A. Dixon ◽  
Rafat Hossain ◽  
Rachna V. Patel ◽  
Holly M. Scott Algood
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Inflammatory Response ◽  
Th17 Cells ◽  
Pathogenic Bacteria ◽  
Cell Activity ◽  
Adverse Outcomes ◽  
T Helper ◽  
Content Type ◽  
Chronic Inflammatory Response

ABSTRACT Helicobacter pylori is a Gram-negative bacterium that infects the gastric epithelia of its human host. Everyone who is colonized with these pathogenic bacteria can develop gastric inflammation, termed gastritis. Additionally, a small proportion of colonized people develop more adverse outcomes, including gastric ulcer disease, gastric adenocarcinoma, or gastric mucosa-associated lymphoid tissue lymphoma. The development of these adverse outcomes is dependent on the establishment of a chronic inflammatory response. The development and control of this chronic inflammatory response are significantly impacted by CD4+ T helper cell activity. Noteworthy, T helper 17 (Th17) cells, a proinflammatory subset of CD4+ T cells, produce several proinflammatory cytokines that activate innate immune cell antimicrobial activity, drive a pathogenic immune response, regulate B cell responses, and participate in wound healing. Therefore, this review was written to take an intricate look at the involvement of Th17 cells and their affiliated cytokines (interleukin-17A [IL-17A], IL-17F, IL-21, IL-22, and IL-26) in regulating the immune response to H. pylori colonization and carcinogenesis.

scholarly journals Combined Bioinformatic and Rational Design Approach To Develop Antimicrobial Peptides against Mycobacterium tuberculosis

2016 ◽  
Vol 60 (5) ◽  
pp. 2757-2764 ◽  
Author(s):  
C. Seth Pearson ◽  
Zachary Kloos ◽  
Brian Murray ◽  
Ebot Tabe ◽  
Monica Gupta ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Antimicrobial Peptides ◽  
Rational Design ◽  
Pathogenic Bacteria ◽  
First Generation ◽  
De Novo ◽  
Specific Activity ◽  
Lung Epithelial Cells ◽  
Content Type ◽  
Low Cytotoxicity

ABSTRACTDrug-resistant pathogens are a growing problem, and novel strategies are needed to combat this threat. Among the most significant of these resistant pathogens isMycobacterium tuberculosis, which is an unusually difficult microbial target due to its complex membrane. Here, we design peptides for specific activity againstM. tuberculosisusing a combination of “database filtering” bioinformatics, protein engineering, andde novodesign. Several variants of these peptides are structurally characterized to validate the design process. The designed peptides exhibit potent activity (MIC values as low as 4 μM) againstM. tuberculosisand also exhibit broad activity against a host of other clinically relevant pathogenic bacteria such as Gram-positive bacteria (Streptococcus) and Gram-negative bacteria (Escherichia coli). They also display excellent selectivity, with low cytotoxicity against cultured macrophages and lung epithelial cells. These first-generation antimicrobial peptides serve as a platform for the design of antibiotics and for investigating structure-activity relationships in the context of theM. tuberculosismembrane. The antimicrobial peptide design strategy is expected to be generalizable for any pathogen for which an activity database can be created.

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