scholarly journals Unusual Sulfur Requirements During Laboratory Growth ofLuteibacter

2017 ◽  
Author(s):  
David A. Baltrus ◽  
A. Elizabeth Arnold
Keyword(s):  
Sulfur Source ◽  
Sulfate Transport ◽  
Differential Growth ◽  
Fungal Host ◽  
Symbiotic Relationships ◽  
Fungal Partner ◽  
Rich Media ◽  
Genes Encoding ◽  
Minimal Media ◽  
Bacteria And Fungi

AbstractMany terrestrial bacteria are assumed to utilize sulfate transport and metabolism as a means for fulfilling cellular sulfur requirements. As such, many defined minimal media for bacterial growth under laboratory conditions contain sulfate as their sulfur source. Herein, an exception to this assumption is described as sulfate transport capabilities have been lost at least once in a lineage ofLuteibacterassociated with plants and fungi. However, a representative of this lineage (an endohyphal species,Luteibactersp. 9143) can grow in minimal media when sulfur is supplemented with organic (cysteine and methionine) or inorganic (thiosulfate) compounds, and when co-cultured with its fungal host. A related strain ofLuteibacter(UNC366Tsa5.1, isolated from the rhizosphere of Arabidopsis) potentially possesses more limited sulfur acquisition pathways thanLuteibactersp. 9143. These results highlight the surprising sulfur requirements ofLuteibacter, which may be illustrative of close associations between these strains and eukaryotes, as well as a need for caution when inferring auxotrophies in a focal strain based on differential growth in minimal versus rich media.ImportanceSulfate is often used as the sulfur source in minimal media. Here we show that someLuteibacterstrains cannot utilize sulfate as a sulfur source, likely due to loss of genes encoding transport proteins. As sulfur requirements forLuteibactercan be met through co-culture with their fungal partner, this knowledge could provide a means to engineer better symbiotic relationships between bacteria and fungi that may be relevant for agriculture. Because growth in minimal media can be restored by supplementation with either cysteine or methionine, and in some cases only methionine, this result highlights how unexpected growth requirements could masquerade as auxotrophy for certain strains and conditions.

scholarly journals Genome Reduction and Secondary Metabolism of the Marine Sponge-Associated Cyanobacterium Leptothoe

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 298
Author(s):  
Despoina Konstantinou ◽  
Rafael V. Popin ◽  
David P. Fewer ◽  
Kaarina Sivonen ◽  
Spyros Gkelis
Keyword(s):  
Natural Products ◽  
Microbial Communities ◽  
Genomic Analysis ◽  
Gene Clusters ◽  
Marine Sponges ◽  
Genome Reduction ◽  
Extracellular Polysaccharides ◽  
Comparative Genomic ◽  
Symbiotic Relationships ◽  
Genes Encoding

Sponges form symbiotic relationships with diverse and abundant microbial communities. Cyanobacteria are among the most important members of the microbial communities that are associated with sponges. Here, we performed a genus-wide comparative genomic analysis of the newly described marine benthic cyanobacterial genus Leptothoe (Synechococcales). We obtained draft genomes from Le. kymatousa TAU-MAC 1615 and Le. spongobia TAU-MAC 1115, isolated from marine sponges. We identified five additional Leptothoe genomes, host-associated or free-living, using a phylogenomic approach, and the comparison of all genomes showed that the sponge-associated strains display features of a symbiotic lifestyle. Le. kymatousa and Le. spongobia have undergone genome reduction; they harbored considerably fewer genes encoding for (i) cofactors, vitamins, prosthetic groups, pigments, proteins, and amino acid biosynthesis; (ii) DNA repair; (iii) antioxidant enzymes; and (iv) biosynthesis of capsular and extracellular polysaccharides. They have also lost several genes related to chemotaxis and motility. Eukaryotic-like proteins, such as ankyrin repeats, playing important roles in sponge-symbiont interactions, were identified in sponge-associated Leptothoe genomes. The sponge-associated Leptothoe stains harbored biosynthetic gene clusters encoding novel natural products despite genome reduction. Comparisons of the biosynthetic capacities of Leptothoe with chemically rich cyanobacteria revealed that Leptothoe is another promising marine cyanobacterium for the biosynthesis of novel natural products.

scholarly journals Regulation of Polysaccharide Utilization Contributes to the Persistence of Group A Streptococcus in the Oropharynx

2007 ◽  
Vol 75 (6) ◽  
pp. 2981-2990 ◽  
Author(s):  
Samuel A. Shelburne ◽  
Nnaja Okorafor ◽  
Izabela Sitkiewicz ◽  
Paul Sumby ◽  
David Keith ◽  
...  
Keyword(s):  
Parental Strain ◽  
Group A Streptococcus ◽  
Transcriptional Regulator ◽  
Human Saliva ◽  
Transcript Levels ◽  
Expression Of Genes ◽  
Rich Media ◽  
Genes Encoding ◽  
Group A ◽  
Mutant Derivative

ABSTRACT Group A Streptococcus (GAS) genes that encode proteins putatively involved in polysaccharide utilization show growth phase-dependent expression in human saliva. We sought to determine whether the putative polysaccharide transcriptional regulator MalR influences the expression of such genes and whether MalR helps GAS infect the oropharynx. Analysis of 32 strains of 17 distinct M protein serotypes revealed that MalR is highly conserved across GAS strains. malR transcripts were detectable in patients with GAS pharyngitis, and the levels increased significantly during growth in human saliva compared to the levels during growth in glucose-containing or nutrient-rich media. To determine if MalR influenced the expression of polysaccharide utilization genes, we compared the transcript levels of eight genes encoding putative polysaccharide utilization proteins in the parental serotype M1 strain MGAS5005 and its ΔmalR isogenic mutant derivative. The transcript levels of all eight genes were significantly increased in the ΔmalR strain compared to the parental strain, especially during growth in human saliva. Following experimental infection, the ΔmalR strain persistently colonized the oropharynx in significantly fewer mice than the parental strain colonized, and the numbers of ΔmalR strain CFU recovered were significantly lower than the numbers of the parental strain CFU recovered. These data led us to conclude that MalR influences the expression of genes putatively involved in polysaccharide utilization and that MalR contributes to the persistence of GAS in the oropharynx.

scholarly journals Dual RNA-Seq Analysis of Trichophyton rubrum and HaCat Keratinocyte Co-Culture Highlights Important Genes for Fungal-Host Interaction

Genes ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 362 ◽  
Author(s):  
Monise Petrucelli ◽  
Kamila Peronni ◽  
Pablo Sanches ◽  
Tatiana Komoto ◽  
Josie Matsuda ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Trichophyton Rubrum ◽  
Glyoxylate Cycle ◽  
Human Keratinocytes ◽  
Rna Seq ◽  
Fungal Host ◽  
Host Interaction ◽  
Genes Encoding ◽  
Hacat Keratinocyte

The dermatophyte Trichophyton rubrum is the major fungal pathogen of skin, hair, and nails that uses keratinized substrates as the primary nutrients during infection. Few strategies are available that permit a better understanding of the molecular mechanisms involved in the interaction of T. rubrum with the host because of the limitations of models mimicking this interaction. Dual RNA-seq is a powerful tool to unravel this complex interaction since it enables simultaneous evaluation of the transcriptome of two organisms. Using this technology in an in vitro model of co-culture, this study evaluated the transcriptional profile of genes involved in fungus-host interactions in 24 h. Our data demonstrated the induction of glyoxylate cycle genes, ERG6 and TERG_00916, which encodes a carboxylic acid transporter that may improve the assimilation of nutrients and fungal survival in the host. Furthermore, genes encoding keratinolytic proteases were also induced. In human keratinocytes (HaCat) cells, the SLC11A1, RNASE7, and CSF2 genes were induced and the products of these genes are known to have antimicrobial activity. In addition, the FLG and KRT1 genes involved in the epithelial barrier integrity were inhibited. This analysis showed the modulation of important genes involved in T. rubrum–host interaction, which could represent potential antifungal targets for the treatment of dermatophytoses.

scholarly journals Molecular Regulation of β-Lactam Biosynthesis in Filamentous Fungi

1998 ◽  
Vol 62 (3) ◽  
pp. 547-585 ◽  
Author(s):  
Axel A. Brakhage
Keyword(s):  
Strain Improvement ◽  
Regulatory Mechanisms ◽  
Primary Metabolism ◽  
Penicillin Biosynthesis ◽  
Enzymatic Reactions ◽  
Genes Encoding ◽  
Dna Elements ◽  
Improvement Programs ◽  
Bacteria And Fungi ◽  
Amino Acid Precursors

SUMMARY The most commonly used β-lactam antibiotics for the therapy of infectious diseases are penicillin and cephalosporin. Penicillin is produced as an end product by some fungi, most notably by Aspergillus (Emericella) nidulans and Penicillium chrysogenum. Cephalosporins are synthesized by both bacteria and fungi, e.g., by the fungus Acremonium chrysogenum (Cephalosporium acremonium). The biosynthetic pathways leading to both secondary metabolites start from the same three amino acid precursors and have the first two enzymatic reactions in common. Penicillin biosynthesis is catalyzed by three enzymes encoded by acvA (pcbAB), ipnA (pcbC), and aatA (penDE). The genes are organized into a cluster. In A. chrysogenum, in addition to acvA and ipnA, a second cluster contains the genes encoding enzymes that catalyze the reactions of the later steps of the cephalosporin pathway (cefEF and cefG). Within the last few years, several studies have indicated that the fungal β-lactam biosynthesis genes are controlled by a complex regulatory network, e.g., by the ambient pH, carbon source, and amino acids. A comparison with the regulatory mechanisms (regulatory proteins and DNA elements) involved in the regulation of genes of primary metabolism in lower eukaryotes is thus of great interest. This has already led to the elucidation of new regulatory mechanisms. Furthermore, such investigations have contributed to the elucidation of signals leading to the production of β-lactams and their physiological meaning for the producing fungi, and they can be expected to have a major impact on rational strain improvement programs. The knowledge of biosynthesis genes has already been used to produce new compounds.

scholarly journals Arabidopsis SAURs are critical for differential light regulation of the development of various organs

2016 ◽  
Vol 113 (21) ◽  
pp. 6071-6076 ◽  
Author(s):  
Ning Sun ◽  
Jiajun Wang ◽  
Zhaoxu Gao ◽  
Jie Dong ◽  
Hang He ◽  
...  
Keyword(s):  
Phosphatase Activity ◽  
Protein Phosphatases ◽  
Light Regulation ◽  
Differential Regulation ◽  
Cell Enlargement ◽  
Differential Growth ◽  
Genes Encoding ◽  
Organ Specific ◽  
Cotyledon Expansion ◽  
Mutation Analyses

During deetiolation of Arabidopsis seedlings, light promotes the expansion of cotyledons but inhibits the elongation of hypocotyls. The mechanism of this differential regulation of cell enlargement is unclear. Our organ-specific transcriptomic analysis identified 32 Small Auxin Up RNA (SAUR) genes whose transcripts were light-induced in cotyledons and/or repressed in hypocotyls. We therefore named these SAURs as lirSAURs. Both overexpression and mutation analyses demonstrated that lirSAURs could promote cotyledon expansion and opening and enhance hypocotyl elongation, possibly by inhibiting phosphatase activity of D-clade type 2C protein phosphatases (PP2C-Ds). Light reduced auxin levels to down-regulate the expression of lirSAURs in hypocotyls. Further, phytochrome-interacting factors (PIFs) were shown to directly bind the genes encoding these SAURs and differentially regulate their expression in cotyledons and hypocotyls. Together, our study demonstrates that light mediates auxin levels and PIF stability to differentially regulate the expression of lirSAURs in cotyledons and hypocotyls, and these lirSAURs further mediate the differential growth of these two organs.

Symbioses and microbes

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Hydrothermal Vents ◽  
Environmental Changes ◽  
Higher Plants ◽  
Homo Sapiens ◽  
Close Contact ◽  
Essential Amino Acids ◽  
Symbiotic Bacteria ◽  
Symbiotic Relationships ◽  
Decreasing Ph ◽  
Bacteria And Fungi

The book ends with a chapter devoted to discussing interactions between microbes and higher plants and animals. Symbiosis is sometimes used to describe all interactions, even negative ones, between organisms in persistent, close contact. This chapter focuses on interactions that benefit both partners (mutualism), or one partner while being neutral to the other (commensalism). Microbes are essential to the health and ecology of vertebrates, including Homo sapiens. Microbial cells outnumber human cells on our bodies, aiding in digestion and warding off pathogens. In consortia similar to the anaerobic food chain of anoxic sediments, microbes are essential in the digestion of plant material by deer, cattle, and sheep. Different types of microbes form symbiotic relationships with insects and help to explain their huge success in the biosphere. Protozoa are crucial for wood-boring insects, symbiotic bacteria in the genus Buchnera provide sugars to host aphids while obtaining essential amino acids in exchange, and fungi thrive in subterranean gardens before being harvested for food by ants. Symbiotic dinoflagellates directly provide organic material to support coral growth in exchange for ammonium and other nutrients. Corals are now threatened worldwide by rising oceanic temperatures, decreasing pH, and other human-caused environmental changes. At hydrothermal vents in some deep oceans, sulfur-oxidizing bacteria fuel an entire ecosystem and endosymbiotic bacteria support the growth of giant tube worms. Higher plants also have many symbiotic relationships with bacteria and fungi. Symbiotic nitrogen-fixing bacteria in legumes and other plants fix more nitrogen than free-living bacteria. Fungi associated with plant roots (“mycorrhizal”) are even more common and potentially provide plants with phosphorus as well as nitrogen. Symbiotic microbes can provide other services to their hosts, such as producing bioluminescence, needed for camouflage against predators. In the case of the bobtail squid, bioluminescence is only turned on when populations of the symbiotic bacteria reach critical levels, determined by a quorum sensing mechanism.

Effects of Thiosulfate as a Sulfur Source on Plant Growth, Metabolites Accumulation and Gene Expression in Arabidopsis and Rice

2019 ◽  
Vol 60 (8) ◽  
pp. 1683-1701 ◽  
Author(s):  
Takatsugu Nakajima ◽  
Yusuke Kawano ◽  
Iwao Ohtsu ◽  
Akiko Maruyuama-Nakashita ◽  
Alaa Allahham ◽  
...  
Keyword(s):  
Sulfur Source ◽  
Sulfate Assimilation ◽  
Targeted Metabolomics ◽  
Gene Expressions ◽  
Root Cells ◽  
Genes Encoding ◽  
Widely Targeted Metabolomics ◽  
Sulfate Metabolism ◽  
Lower Biomass ◽  
Reduced State

Abstract Plants are considered to absorb sulfur from their roots in the form of sulfate. In bacteria like Escherichia coli, thiosulfate is a preferred sulfur source. It is converted into cysteine (Cys). This transformation consumes less NADPH and ATP than sulfate assimilation into Cys. In Saccharomyces cerevisiae, thiosulfate promoted growth more than sulfate. In the present study, the availability of thiosulfate, the metabolite transformations and gene expressions it induces were investigated in Arabidopsis and rice as model dicots and monocots, respectively. In Arabidopsis, the thiosulfate-amended plants had lower biomass than those receiving sulfate when sulfur concentrations in the hydroponic medium were above 300 μM. In contrast, rice biomass was similar for plants raised on thiosulfate and sulfate at 300 μM sulfur. Therefore, both plants can use thiosulfate but it is a better sulfur source for rice. In both plants, thiosulfate levels significantly increased in roots following thiosulfate application, indicating that the plants absorbed thiosulfate into their root cells. Thiosulfate is metabolized in plants by a different pathway from that used for sulfate metabolism. Thiosulfate increases plant sulfide and cysteine persulfide levels which means that plants are in a more reduced state with thiosulfate than with sulfate. The microarray analysis of Arabidopsis roots revealed that 13 genes encoding Cys-rich proteins were upregulated more with thiosulfate than with sulfate. These results together with those of the widely targeted metabolomics analysis were used to proposes a thiosulfate assimilation pathway in plants.

Cecropins contribute to Drosophila host defense against a subset of fungal and Gram-negative bacterial infection

Genetics ◽  
2021 ◽  
Author(s):  
Alexia L Carboni ◽  
Mark A Hanson ◽  
Scott A Lindsay ◽  
Steven A Wasserman ◽  
Bruno Lemaitre
Keyword(s):  
Host Defense ◽  
Gram Negative Bacteria ◽  
Insect Host ◽  
Wild Type ◽  
Systemic Immune Response ◽  
Gram Negative ◽  
Genes Encoding ◽  
Bacteria And Fungi ◽  
Secreted Peptides

Abstract Cecropins are small helical secreted peptides with antimicrobial activity that are widely distributed among insects. Genes encoding cecropins are strongly induced upon infection, pointing to their role in host-defense. In Drosophila, four cecropin genes clustered in the genome (CecA1, CecA2, CecB and CecC) are expressed upon infection downstream of the Toll and Imd pathways. In this study, we generated a short deletion ΔCecA-C removing the whole cecropin locus. Using the ΔCecA-C deficiency alone or in combination with other antimicrobial peptide (AMP) mutations, we addressed the function of cecropins in the systemic immune response. ΔCecA-C flies were viable and resisted challenge with various microbes as wild-type. However, removing ΔCecA-C in flies already lacking ten other AMP genes revealed a role for cecropins in defense against Gram-negative bacteria and fungi. Measurements of pathogen loads confirm that cecropins contribute to the control of certain Gram-negative bacteria, notably Enterobacter cloacae and Providencia heimbachae. Collectively, our work provides the first genetic demonstration of a role for cecropins in insect host defense, and confirms their in vivo activity primarily against Gram-negative bacteria and fungi. Generation of a fly line (ΔAMP14) that lacks fourteen immune inducible AMPs provides a powerful tool to address the function of these immune effectors in host-pathogen interactions and beyond.

scholarly journals Gene Expression Response ofTrichophyton rubrumduring Coculture on Keratinocytes Exposed to Antifungal Agents

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Tatiana Takahasi Komoto ◽  
Tamires Aparecida Bitencourt ◽  
Gabriel Silva ◽  
Rene Oliveira Beleboni ◽  
Mozart Marins ◽  
...  
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Citrate Synthase ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Serine Proteinase ◽  
Gene Expression Response ◽  
Fungal Host ◽  
Host Interaction ◽  
Genes Encoding

Trichophyton rubrumis the most common causative agent of dermatomycoses worldwide, causing infection in the stratum corneum, nails, and hair. Despite the high prevalence of these infections, little is known about the molecular mechanisms involved in the fungal-host interaction, particularly during antifungal treatment. The aim of this work was to evaluate the gene expression ofT. rubrumcocultured with keratinocytes and treated with the flavonoidtrans-chalcone and the glycoalkaloidα-solanine. Both substances showed a marked antifungal activity againstT. rubrumstrain CBS (MIC = 1.15 and 17.8 µg/mL, resp.). Cytotoxicity assay against HaCaT cells produced IC50values of 44.18 totrans-chalcone and 61.60 µM toα-solanine. The interaction of keratinocytes withT. rubrumconidia upregulated the expression of genes involved in the glyoxylate cycle, ergosterol synthesis, and genes encoding proteases but downregulated the ABC transporterTruMDR2 gene. However, both antifungals downregulated the ERG1 and ERG11, metalloprotease 4, serine proteinase, andTruMDR2 genes. Furthermore, thetrans-chalcone downregulated the genes involved in the glyoxylate pathway, isocitrate lyase, and citrate synthase. Considering the urgent need for more efficient and safer antifungals, these results contribute to a better understanding of fungal-host interactions and to the discovery of new antifungal targets.

scholarly journals Expression and characterization of a cutinase (AnCUT2) from Aspergillus niger

2016 ◽  
Vol 11 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Khadijah Ahmed Al-Tammar ◽  
Othman Omar ◽  
Abdul Munir Abdul Murad ◽  
Farah Diba Abu Bakar
Keyword(s):  
Aspergillus Niger ◽  
Hydrolytic Activity ◽  
Water Soluble ◽  
Synthetic Fiber ◽  
Amino Acid Residues ◽  
Efficient Catalyst ◽  
Reading Frame ◽  
Synthetic Fibers ◽  
Genes Encoding ◽  
Bacteria And Fungi

AbstractCutin hydrolase (EC 3.1.1.74), an extracellular polyesterase found in pollens, bacteria and fungi, is an efficient catalyst that exhibits hydrolytic activity on a variety of water-soluble esters, synthetic fibers, plastics and triglycerides. Thus, cutinase can be used in various applications such as ester synthesis, bio-scouring, food and detergent industries. Ancut2 is one of five genes encoding cutinases present in the Aspergillus niger ATCC 10574 genome. The cDNA of Ancut2 comprising of an open reading frame of 816 bp encoding a protein of 271 amino acid residues, was isolated and expressed in Pichia pastoris. The partially purified recombinant cutinase exhibited a molecular mass of approximately 40 kDa. The enzyme showed highest activity at 40°C with a preference for acidic pH (5.0-6.0). AnCUT2 showed hydrolytic activity towards various p-nitrophenyl esters with preference towards shorter chain esters such as p-nitrophenyl butyrate (C4). Scanning Electron Microscopy demonstrated that AnCUT2 was capable of modifying surfaces of synthetic polycaprolactone and polyethylene terephthalate plastics. The properties of this enzyme suggest that it may be applied in synthetic fiber modification and fruit processing industries.

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