Molecular Origins of Transcriptional Heterogeneity in Diazotrophic Klebsiella oxytoca.

Phenotypic heterogeneity in clonal bacterial batch cultures has been shown for a range of bacterial systems; however, the molecular origins of such heterogeneity and its magnitude are not well understood. Under conditions of extreme low-nitrogen stress in the model diazotroph Klebsiella oxytoca, we found remarkably high heterogeneity of gene expression, which codes for the structural genes of nitrogenase, one key enzyme of the global nitrogen cycle. This heterogeneity limited the bulk observed nitrogen-fixing capacity of the population.

Resource Allocation During the Transition to Diazotrophy in .

Free-living nitrogen-fixing bacteria can improve growth yields of some non-leguminous plants and, if enhanced through bioengineering approaches, have the potential to address major nutrient imbalances in global crop production by supplementing inorganic nitrogen fertilisers. However, nitrogen fixation is a highly resource-costly adaptation and is de-repressed only in environments in which sources of reduced nitrogen are scarce. Here we investigate nitrogen fixation () gene expression and nitrogen starvation response signaling in the model diazotroph () M5a1 during ammonium depletion and the transition to growth on atmospheric N.

Shank3-deficient thalamocortical neurons show HCN channelopathy and alterations in intrinsic electrical properties.

Key Points: Shank3 increases the HCN channel surface expression in heterologous expression systems. Shank3 deficiency causes significant reduction in HCN2 expression and I current amplitude in thalamocortical (TC) neurons. Shank3 - but not Shank3 -deficient TC neurons share changes in basic electrical properties which are comparable to those of HCN2-/- TC neurons.

Mutualism between SGM 81 and in modulating root plasticity and rhizospheric bacterial density.

Aims: is a commercially important ornamental flower. Plant growth promoting rhizobacteria are increasingly applied as bio-fertilisers and bio-fortifiers. We studied the effect of a rhizospheric isolate SGM 81 strain to promote growth under sterile and non-sterile conditions, to colonise its root system endophytically and its impact on the cultivatable microbial community.

A worldwide survey of retinopathy of prematurity screening.

Background: To ascertain which countries in the world have retinopathy of prematurity (ROP) screening programmes and guidelines and how these were developed.

Methods: An email database was created and requests were sent to ophthalmologists in 141 nations to complete an online survey on ROP screening in their country.

Results: Representatives from 92/141 (65%) countries responded.

Functional Characterization of Key Residues in Regulatory Proteins HrpG and HrpV of Pseudomonas syringae pv. tomato DC3000.

The plant pathogen Pseudomonas syringae pv. tomato DC3000 uses a type III secretion system (T3SS) to transfer effector proteins into the host. The expression of T3SS proteins is controlled by the HrpL σ factor.

Evading plant immunity: feedback control of the T3SS in .

Microbes are responsible for over 10% of the global yield losses in staple crops such as wheat, rice, and maize. Understanding the decision-making strategies that enable bacterial plant pathogens to evade the host immune system and cause disease is essential for managing their ever growing threat to food security. Many utilise the needle-like type III secretion system (T3SS) to suppress plant immunity, by injecting effector proteins that inhibit eukaryotic signalling pathways into the host cell cytoplasm.

Negative Autogenous Control of the Master Type III Secretion System Regulator HrpL in Pseudomonas syringae.

Unlabelled: The type III secretion system (T3SS) is a principal virulence determinant of the model bacterial plant pathogen Pseudomonas syringae T3SS effector proteins inhibit plant defense signaling pathways in susceptible hosts and elicit evolved immunity in resistant plants. The extracytoplasmic function sigma factor HrpL coordinates the expression of most T3SS genes. Transcription of hrpL is dependent on sigma-54 and the codependent enhancer binding proteins HrpR and HrpS for hrpL promoter activation.

Orbital Imaging to Identify a "Lost" Lateral Rectus Muscle.

A 36-year-old man presented with a large-angle esotropia and limited abduction of the right eye. A computed tomography scan of his orbits showed an absent lateral rectus muscle. At the time of surgery, a normal-appearing lateral rectus muscle was found.

C. elegans Demonstrates Distinct Behaviors within a Fixed and Uniform Electric Field.

C. elegans will orient and travel in a straight uninterrupted path directly towards the negative pole of a DC electric field. We have sought to understand the strategy worms use to navigate to the negative pole in a uniform electric field that is fixed in both direction and magnitude.

In vitro and in vivo methodologies for studying the Sigma 54-dependent transcription.

Here we describe approaches and methods to assaying in vitro the major variant bacterial sigma factor, Sigma 54 (σ(54)), in a purified system. We include the complete transcription system, binding interactions between σ54 and its activators, as well as the self-assembly and the critical ATPase activity of the cognate activators which serve to remodel the closed promoter complexes. We also present in vivo methodologies that are used to study the impact of physiological processes, metabolic states, global signalling networks, and cellular architecture on the control of σ(54)-dependent gene expression.

Regulation of synaptic transmission at the Caenorhabditis elegans M4 neuromuscular junction by an antagonistic relationship between two calcium channels.

In wild-type Caenorhabditis elegans, the synapse from motor neuron M4 to pharyngeal terminal bulb (TB) muscles is silent, and the muscles are instead excited by gap junction connections from adjacent muscles. An eat-5 innexin mutant lacking this electrical connection has few TB contractions and is unable to grow well on certain foods. We showed previously that this defect can be overcome by activation of the M4 → TB synapse.

Differential secretome analysis of Pseudomonas syringae pv tomato using gel-free MS proteomics.

The plant pathogen Pseudomonas syringae pv.tomato (DC3000) causes virulence by delivering effector proteins into host plant cells through its type three secretion system (T3SS). In response to the plant environment DC3000 expresses hypersensitive response and pathogenicity genes (hrp).

Chp8, a diguanylate cyclase from Pseudomonas syringae pv. Tomato DC3000, suppresses the pathogen-associated molecular pattern flagellin, increases extracellular polysaccharides, and promotes plant immune evasion.

Unlabelled: The bacterial plant pathogen Pseudomonas syringae causes disease in a wide range of plants. The associated decrease in crop yields results in economic losses and threatens global food security. Competition exists between the plant immune system and the pathogen, the basic principles of which can be applied to animal infection pathways.

Determination of the self-association residues within a homomeric and a heteromeric AAA+ enhancer binding protein.

The σ(54)-dependent transcription in bacteria requires specific activator proteins, bacterial enhancer binding protein (bEBP), members of the AAA+ (ATPases Associated with various cellular Activities) protein family. The bEBPs usually form oligomers in order to hydrolyze ATP and make open promoter complexes. The bEBP formed by HrpR and HrpS activates transcription from the σ(54)-dependent hrpL promoter responsible for triggering the Type Three Secretion System in Pseudomonas syringae pathovars.

Intravitreal bevacizumab for iris neovascularization following proton beam irradiation for choroidal melanoma.

Objective: To evaluate the safety and efficacy of intravitreal injections of bevacizumab as an eye-sparing treatment for iris neovascularization (NVI) following proton beam irradiation for choroidal melanoma.

Design: Retrospective interventional case series.

Participants: Four patients who received intravitreal bevacizumab for NVI following proton beam irradiation for choroidal melanoma were identified in the Department of Ophthalmology archives at the University of British Columbia.