Automated cell tracking using 3D nnUnet and Light Sheet Microscopy to quantify regional deformation in zebrafish.

Light Sheet Microscopy (LSM) in conjunction with embryonic zebrafish, is rapidly advancing three-dimensional, characterization of myocardial contractility. Preclinical cardiac deformation imaging is predominantly restricted to a low-order dimensionality image space (2D) or suffers from poor reproducibility. In this regard, LSM has enabled high throughput, non-invasive 4D (3d+time) characterization of dynamic organogenesis within the transparent zebrafish model.

Streptothricin F is a bactericidal antibiotic effective against highly drug-resistant gram-negative bacteria that interacts with the 30S subunit of the 70S ribosome.

The streptothricin natural product mixture (also known as nourseothricin) was discovered in the early 1940s, generating intense initial interest because of excellent gram-negative activity. Here, we establish the activity spectrum of nourseothricin and its main components, streptothricin F (S-F, 1 lysine) and streptothricin D (S-D, 3 lysines), purified to homogeneity, against highly drug-resistant, carbapenem-resistant Enterobacterales (CRE) and Acinetobacter baumannii. For CRE, the MIC50 and MIC90 for S-F and S-D were 2 and 4 μM, and 0.

A Versatile Nanoluciferase Reporter Reveals Structural Properties Associated with a Highly Efficient, N-Terminal Legionella pneumophila Type IV Secretion Translocation Signal.

Many Gram-negative pathogens rely on type IV secretion systems (T4SS) for infection. One limitation has been the lack of ideal reporters to identify T4SS translocated effectors and study T4SS function. Most reporter systems make use of fusions to reporter proteins, in particular, β-lactamase (TEM) and calmodulin-dependent adenylate cyclase (CYA), that allow detection of translocated enzymatic activity inside host cells.

Introducing the ArsR-Regulated Arsenic Stimulon.

The microbial operon encodes the primary bacterial defense response to the environmental toxicant, arsenic. An important component of this operon is the gene, which encodes ArsR, a member of the family of proteins categorized as DNA-binding transcriptional repressors. As currently documented, ArsR regulates its own expression as well as other genes in the same operon.

Metabolic Responses to Arsenite Exposure Regulated through Histidine Kinases PhoR and AioS in 5A.

Arsenite (As) oxidation is a microbially-catalyzed transformation that directly impacts arsenic toxicity, bioaccumulation, and bioavailability in environmental systems. The genes for As oxidation () encode a periplasmic As sensor AioX, transmembrane histidine kinase AioS, and cognate regulatory partner AioR, which control expression of the As oxidase AioBA. The genes are under ultimate control of the phosphate stress response via histidine kinase PhoR.

A Chemical Genetics Screen Reveals Influence of p38 Mitogen-Activated Protein Kinase and Autophagy on Phagosome Development and Intracellular Replication of Brucella neotomae in Macrophages.

is an intracellular bacterial pathogen that causes chronic systemic infection in domesticated livestock and poses a zoonotic infectious risk to humans. The virulence of is critically dependent on its ability to replicate and survive within host macrophages. modulates host physiological pathways and cell biology in order to establish a productive intracellular replicative niche.

Transcriptomics analysis defines global cellular response of Agrobacterium tumefaciens 5A to arsenite exposure regulated through the histidine kinases PhoR and AioS.

In environments where arsenic and microbes coexist, microbes are the principal drivers of arsenic speciation, which directly affects bioavailability, toxicity and bioaccumulation. Speciation reactions influence arsenic behaviour in environmental systems, directly affecting human and agricultural exposures. Arsenite oxidation decreases arsenic toxicity and mobility in the environment, and therefore understanding its regulation and overall influence on cellular metabolism is of significant interest.

Recapitulates Attributes of Zoonotic Human Disease in a Murine Infection Model.

Members of the genus are Gram-negative pathogens that cause chronic systemic infection in farm animals and zoonotic infection in humans. Study of the genus has been hindered by the need for biosafety level 3 select agent containment. , originally isolated from the desert pack rat, presented an opportunity to develop an alternative, non-select agent experimental model.

Phosphate starvation response controls genes required to synthesize the phosphate analog arsenate.

Environmental arsenic poisoning affects roughly 200 million people worldwide. The toxicity and mobility of arsenic in the environment is significantly influenced by microbial redox reactions, with arsenite (As ) being more toxic than arsenate (As ). Microbial oxidation of As to As is known to be regulated by the AioXSR signal transduction system and viewed to function for detoxification or energy generation.

Promotion and Rescue of Intracellular Brucella neotomae Replication during Coinfection with Legionella pneumophila.

We established a new model system for study of type IV secretion system-dependent (T4SS) pathogenesis in the genus. Importantly, is a rodent pathogen, and unlike , , and , has not been observed to infect humans. It therefore can be handled more facilely using biosafety level 2 practices.

High Throughput, Real-time, Dual-readout Testing of Intracellular Antimicrobial Activity and Eukaryotic Cell Cytotoxicity.

Traditional measures of intracellular antimicrobial activity and eukaryotic cell cytotoxicity rely on endpoint assays. Such endpoint assays require several additional experimental steps prior to readout, such as cell lysis, colony forming unit determination, or reagent addition. When performing thousands of assays, for example, during high-throughput screening, the downstream effort required for these types of assays is considerable.

Regulatory Activities of Four ArsR Proteins in Agrobacterium tumefaciens 5A.

Unlabelled: ArsR is a well-studied transcriptional repressor that regulates microbe-arsenic interactions. Most microorganisms have an arsR gene, but in cases where multiple copies exist, the respective roles or potential functional overlap have not been explored. We examined the repressors encoded by arsR1 and arsR2 (ars1 operon) and by arsR3 and arsR4 (ars2 operon) in Agrobacterium tumefaciens 5A.

Arsenite oxidase also functions as an antimonite oxidase.

Arsenic and antimony are toxic metalloids and are considered priority environmental pollutants by the U.S. Environmental Protection Agency.

Involvement of the Acr3 and DctA anti-porters in arsenite oxidation in Agrobacterium tumefaciens 5A.

Microbial arsenite (AsIII) oxidation forms a critical piece of the arsenic cycle in nature, though our understanding of how and why microorganisms oxidize AsIII remains rudimentary. Our model organism Agrobacterium tumefaciens 5A contains two distinct ars operons (ars1 and ars2) that are similar in their coding region content. The ars1 operon is located nearby the aio operon that is essential for AsIII oxidation.

Integrated co-regulation of bacterial arsenic and phosphorus metabolisms.

Arsenic ranks first on the US Environmental Protection Agency Superfund List of Hazardous Substances. Its mobility and toxicity depend upon chemical speciation, which is significantly driven by microbial redox transformations. Genome sequence-enabled surveys reveal that in many microorganisms genes essential to arsenite (AsIII) oxidation are located immediately adjacent to genes coding for functions associated with phosphorus (Pi) acquisition, implying some type of functional importance to the metabolism of As, Pi or both.

Involvement of RpoN in regulating bacterial arsenite oxidation.

In this study with the model organism Agrobacterium tumefaciens, we used a combination of lacZ gene fusions, reverse transcriptase PCR (RT-PCR), and deletion and insertional inactivation mutations to show unambiguously that the alternative sigma factor RpoN participates in the regulation of As(III) oxidation. A deletion mutation that removed the RpoN binding site from the aioBA promoter and an aacC3 (gentamicin resistance) cassette insertional inactivation of the rpoN coding region eliminated aioBA expression and As(III) oxidation, although rpoN expression was not related to cell exposure to As(III). Putative RpoN binding sites were identified throughout the genome and, as examples, included promoters for aioB, phoB1, pstS1, dctA, glnA, glnB, and flgB that were examined by using qualitative RT-PCR and lacZ reporter fusions to assess the relative contribution of RpoN to their transcription.

Acinetobacter oleivorans sp. nov. is capable of adhering to and growing on diesel-oil.

A diesel-oil and n-hexadecane-degrading novel bacterial strain, designated DR1(T), was isolated from a rice paddy in Deok-So, South Korea. The strain DR1(T) cells were Gram-negative, aerobic coccobacilli, and grew at 20-37°C with the optimal temperature of 30°C, and an optimal pH of 6-8. Interestingly, strain DR1(T) was highly motile (swimming and swarming motility) using its fimbriae, and generated N-acyl homoserine lactones as quorum-sensing signals.

Trade-off between antibiotic resistance and biological fitness in Acinetobacter sp. strain DR1.

Rifampicin, a bactericidal antibiotic drug, is routinely used to make an environmental recipient selective in laboratory-conjugation experiments. We noticed, inadvertently, that the rifampicin-resistant Acinetobacter sp. strain DR1, a recently discovered hexadecane-degrading environmental isolate, exhibited a substantial loss of quorum sensing signalling.

Protection against diesel oil toxicity by sodium chloride-induced exopolysaccharides in Acinetobacter sp. strain DR1.

Acinetobacter sp. strain DR1 is capable of growth on diesel oil. Interestingly, the degradation of diesel oil by the strain DR1 is enhanced in the presence of sodium chloride (NaCl).

Inhibitory effect of aged-petroleum hydrocarbons on the survival of inoculated microorganism in a crude-oil contaminated site.

We studied the effects of aged total petroleum hydrocarbons (aged TPH) on the survival of allochthonous diesel-degrading Rhodococcus sp. strain YS-7 in both laboratory and field investigations. The aged TPH extracted from a crude oil-contaminated site were fractionized by thin-layer chromatography/flame ionization detection (TLC/FID).

Antibacterial activity of a disaccharide isolated from Streptomyces sp. strain JJ45 against Xanthomonas sp.

Of the 316 actinomycetes strains isolated from various habitats, Streptomyces sp. strain JJ45 showed the strongest antibiotic activity against the plant pathogenic bacteria Xanthomonas campestris pv. campestris and was thus chosen for further study.

Molecular characterization of fprB (ferredoxin-NADP+ reductase) in Pseudomonas putida KT2440.

The fpr gene, which encodes a ferredoxin-NADP+ reductase, is known to participate in the reversible redox reactions between NADP+/NADPH and electron carriers, such as ferredoxin or flavodoxin. The role of Fpr and its regulatory protein, FinR, in Pseudomonas putida KT2440 on the oxidative and osmotic stress responses has already been characterized [Lee at al. (2006).

Methylobacterium platani sp. nov., isolated from a leaf of the tree Platanus orientalis.

A novel bacterial strain, designated PMB02(T), was isolated from a leaf of the tree Platanus orientalis. Colonies grown on TYG agar plates were circular, pink-pigmented and slow-growing, being 0.2-1.

Overexpressing antioxidant enzymes enhances naphthalene biodegradation in Pseudomonas sp. strain As1.

We tested the hypothesis that during metabolism of naphthalene and other substrates by Pseudomonas sp. strain As1 oxidative stress arises and can be reduced by antioxidant enzymes. Our approach was to prepare plasmid constructs that conferred expression of two single antioxidant enzymes [Fpr (ferredoxin-NADP(+) reductase) and SOD (superoxide dismutase)] and the pair of enzymes SOD plus AhpC (alkyl hydroperoxide reductase).