Isolation and Whole-Genome Sequencing of Four Antibiotic-Producing Pseudomonas Strains.

Here, we report the isolation, whole-genome sequencing, and annotation of four novel Pseudomonas isolates. We also evaluate the biosynthetic potential of each genome.

Draft Genome Sequences of the Three Strains AB1, ST3, and ZL223.

To increase the genomic data available for antibiotic discovery, three independently isolated antibiotic-producing strains were sequenced. No more than 84% average nucleotide identity was shared with publicly available genomes, and a low similarity of predicted biosynthetic gene clusters to known clusters was found.

Assessment and verification of commercially available pressure cookers for laboratory sterilization.

Laboratory science requires careful maintenance of sterile reagents and tools as well as the sterilization of waste prior to disposal. However, steam autoclaves typically used for this purpose may not be readily accessible to everyone in the scientific community, such as K-12 teachers, researchers in the field, students in under-funded laboratories, or persons in the developing world who lack funding and resources. This work examines the use of commercial electric pressure cookers as an alternative method for the sterilization of media, instruments, and waste.

Anabaena sp. strain PCC 7120: Laboratory Maintenance, Cultivation, and Heterocyst Induction.

Anabaena sp. strain PCC 7120 is a multicellular, filamentous, freshwater cyanobacterium that is capable of differentiating specialized heterocyst cells for nitrogen fixation. This unit includes protocols for the growth and maintenance of Anabaena appropriate for a research or teaching laboratory.

Phenotypic Assessment Suggests Multiple Start Codons for HetN, an Inhibitor of Heterocyst Differentiation, in Anabaena sp. Strain PCC 7120.

Multicellular organisms must carefully regulate the timing, number, and location of specialized cellular development. In the filamentous cyanobacterium sp. strain PCC 7120, nitrogen-fixing heterocysts are interspersed between vegetative cells in a periodic pattern to achieve an optimal exchange of bioavailable nitrogen and reduced carbon.

The hetZ gene indirectly regulates heterocyst development at the level of pattern formation in Anabaena sp. strain PCC 7120.

Multicellular development requires the careful orchestration of gene expression to correctly create and position specialized cells. In the filamentous cyanobacterium Anabaena sp. strain PCC 7120, nitrogen-fixing heterocysts are differentiated from vegetative cells in a reproducibly periodic and physiologically relevant pattern.

The heterocyst regulatory protein HetP and its homologs modulate heterocyst commitment in sp. strain PCC 7120.

The commitment of differentiating cells to a specialized fate is fundamental to the correct assembly of tissues within a multicellular organism. Because commitment is often irreversible, entry into and progression through this phase of development must be tightly regulated. Under nitrogen-limiting conditions, the multicellular cyanobacterium sp.

Mutation of the murC and murB Genes Impairs Heterocyst Differentiation in Anabaena sp. Strain PCC 7120.

Unlabelled: To stabilize cellular integrity in the face of environmental perturbations, most bacteria, including cyanobacteria, synthesize and maintain a strong, flexible, three-dimensional peptidoglycan lattice. Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium capable of differentiating morphologically distinct nitrogen-fixing heterocyst cells in a periodic pattern.

The trpE gene negatively regulates differentiation of heterocysts at the level of induction in Anabaena sp. strain PCC 7120.

Levels of 2-oxoglutarate (2-OG) reflect nitrogen status in many bacteria. In heterocystous cyanobacteria, a spike in the 2-OG level occurs shortly after the removal of combined nitrogen from cultures and is an integral part of the induction of heterocyst differentiation. In this work, deletion of one of the two annotated trpE genes in Anabaena sp.

Transcriptional dynamics of developmental genes assessed with an FMN-dependent fluorophore in mature heterocysts of Anabaena sp. strain PCC 7120.

Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that differentiates nitrogen-fixing heterocysts when available combined nitrogen is limiting. Growth under diazotrophic conditions results in a mixture of 'new' (recently differentiated) and 'old' (mature) heterocysts.

The hmp chemotaxis cluster regulates gliding in the filamentous cyanobacterium Nostoc punctiforme.

Many bacteria are capable of movement over surfaces without flagella or pili; they glide. Nostoc punctiforme is a cyanobacterium that differentiates specialized gliding filaments called hormogonia, but the mechanism underlying their movement is currently unknown. Risser et al.

Expanding the direct HetR regulon in Anabaena sp. strain PCC 7120.

In response to a lack of environmental combined nitrogen, the filamentous cyanobacterium Anabaena sp. strain PCC 7120 differentiates nitrogen-fixing heterocyst cells in a periodic pattern. HetR is a transcription factor that coordinates the regulation of this developmental program.

Selective penicillin-binding protein imaging probes reveal substructure in bacterial cell division.

The peptidoglycan cell wall is a common target for antibiotic therapy, but its structure and assembly are only partially understood. Peptidoglycan synthesis requires a suite of penicillin-binding proteins (PBPs), the individual roles of which are difficult to determine because each enzyme is often dispensable for growth perhaps due to functional redundancy. To address this challenge, we sought to generate tools that would enable selective examination of a subset of PBPs.

Molecular characterization of the flagellar hook in Bacillus subtilis.

The structure of the Gram-positive flagellum is poorly understood, and Bacillus subtilis encodes three proteins homologous to the flagellar hook protein from Salmonella enterica. Here we generated a modified B. subtilis hook protein that could be fluorescently stained using a cysteine-reactive dye.

SlrA/SinR/SlrR inhibits motility gene expression upstream of a hypersensitive and hysteretic switch at the level of σ(D) in Bacillus subtilis.

Exponentially growing Bacillus subtilis cultures are epigenetically differentiated into two subpopulations in which cells are either ON or OFF for σ(d) -dependent gene expression: a pattern suggestive of bistability. The gene encoding σ(D) , sigD, is part of the 31-gene fla/che operon where its location at the 3' end, 25 kb away from the strong P(fla/che) promoter, determines its expression level relative to a threshold. Here we show that addition of a single extra copy of the slrA gene in the chromosome inhibited σ(d) -dependent gene expression.

DegU-phosphate activates expression of the anti-sigma factor FlgM in Bacillus subtilis.

The bacterial flagellum is a complex molecular machine that is assembled by more than 30 proteins and is rotated to propel cells either through liquids or over solid surfaces. Flagellar gene expression is extensively regulated to co-ordinate flagellar assembly in both space and time. In Bacillus subtilis, the proteins of unknown function, SwrA and SwrB, and the alternative sigma factor σ(D) are required to activate expression of the flagellar filament protein, flagellin.

Gene position in a long operon governs motility development in Bacillus subtilis.

Growing cultures of Bacillus subtilis bifurcate into subpopulations of motile individuals and non-motile chains of cells that are differentiated at the level of gene expression. The motile cells are ON and the chaining cells are OFF for transcription that depends on RNA polymerase and the alternative sigma factor sigma(D). Here we show that chaining cells were OFF for sigma(D)-dependent gene expression because sigma(D) levels fell below a threshold and sigma(D) activity was inhibited by the anti-sigma factor FlgM.