Germination and outgrowth of Bacillus mycoides KBAB4 spores are impacted by environmental pH, quantitatively analyzed at single cell level with sporetracker.

Quantifying spore germination and outgrowth heterogeneity is challenging. Single cell level analysis should provide supplementary knowledge regarding the impact of unfavorable conditions on germination and outgrowth dynamics. This work aimed to quantify the impact of pH on spore germination and outgrowth, investigating the behavior of individual spore crops, produced under optimal and suboptimal conditions.

Evolution of longitudinal division in multicellular bacteria of the Neisseriaceae family.

Rod-shaped bacteria typically elongate and divide by transverse fission. However, several bacterial species can form rod-shaped cells that divide longitudinally. Here, we study the evolution of cell shape and division mode within the family Neisseriaceae, which includes Gram-negative coccoid and rod-shaped species.

Visualization of SpoVAEa Protein Dynamics in Dormant Spores of and Dynamic Changes in Their Germinosomes and SpoVAEa during Germination.

Bacillus cereus spores, like most spores, can survive for years and germinate when their surroundings become suitable, and germination proteins play an important role in the initiation of germination. Because germinated spores lose the extreme resistance of dormant spores, information on the function of germination proteins could be useful in developing new strategies to control B. cereus spores.

Organization and dynamics of the SpoVAEa protein and its surrounding inner membrane lipids, upon germination of Bacillus subtilis spores.

The SpoVA proteins make up a channel in the inner membrane (IM) of Bacillus subtilis spores. This channel responds to signals from activated germinant receptors (GRs), and allows release of Ca-DPA from the spore core during germination. In the current work, we studied the location and dynamics of SpoVAEa in dormant spores.

Heat Activation and Inactivation of Bacterial Spores: Is There an Overlap?

Heat activation at a sublethal temperature is widely applied to promote species spore germination. This treatment also has the potential to be employed in food processing to eliminate undesired bacterial spores by enhancing their germination and then inactivating the less-heat-resistant germinated spores at a milder temperature. However, incorrect heat treatment could also generate heat damage in spores and lead to more heterogeneous spore germination.

Dynamics of Germinosome Formation and FRET-Based Analysis of Interactions between GerD and Germinant Receptor Subunits in Spores.

Spores of the bacterium can cause disease in humans due to contamination of raw materials for food manufacturing. These dormant, resistant spores can survive for years in the environment, but can germinate and grow when their surroundings become suitable, and spore germination proteins play an important role in the decision to germinate. Since germinated spores have lost dormant spores' extreme resistance, knowledge about the formation and function of germination proteins could be useful in suggesting new preservation strategies to control spores.

Investigating Synthesis of the MalS Malic Enzyme during Bacillus subtilis Spore Germination and Outgrowth and the Influence of Spore Maturation and Sporulation Conditions.

Spore-forming bacteria of the orders and play a major role in food spoilage and foodborne diseases. When environmental conditions become favorable, these spores can germinate as the germinant receptors located on the spore's inner membrane are activated via germinant binding. This leads to the formation of vegetative cells via germination and subsequent outgrowth and potential deleterious effects on foods.

Visualization of Germination Proteins in Putative Germinosomes.

can survive in the form of spores for prolonged periods posing a serious problem for the manufacture of safe shelf-stable foods of optimal quality. Our study aims at increasing knowledge of spores focusing primarily on germination mechanisms to develop novel milder food preservation strategies. Major features of spores are a core with the genetic material encased by multiple protective layers, an important one being the spores' inner membrane (IM), the location of many important germination proteins.

A live-cell super-resolution technique demonstrated by imaging germinosomes in wild-type bacterial spores.

Time-lapse fluorescence imaging of live cells at super-resolution remains a challenge, especially when the photon budget is limited. Current super-resolution techniques require either the use of special exogenous probes, high illumination doses or multiple image acquisitions with post-processing or combinations of the aforementioned. Here, we describe a new approach by combining annular illumination with rescan confocal microscopy.

Distinct Requirements for Tail-Anchored Membrane Protein Biogenesis in Escherichia coli.

Tail-anchored membrane proteins (TAMPs) are a distinct subset of inner membrane proteins (IMPs) characterized by a single C-terminal transmembrane domain (TMD) that is responsible for both targeting and anchoring. Little is known about the routing of TAMPs in bacteria. Here, we have investigated the role of TMD hydrophobicity in tail-anchor function in and its influence on the choice of targeting/insertion pathway.

A Bidimensional Segregation Mode Maintains Symbiont Chromosome Orientation toward Its Host.

All living organisms require accurate segregation of their genetic material. However, in microbes, chromosome segregation is less understood than replication and cell division, which makes its decipherment a compelling research frontier. Furthermore, it has only been studied in free-living microbes so far.

Assessing Membrane Fluidity and Visualizing Fluid Membrane Domains in Bacteria Using Fluorescent Membrane Dyes.

Membrane fluidity is a key parameter of bacterial membranes that undergoes quick adaptation in response to environmental challenges and has recently emerged as an important factor in the antibacterial mechanism of membrane-targeting antibiotics. The specific level of membrane fluidity is not uniform across the bacterial cell membrane. Rather, specialized microdomains associated with different cellular functions can exhibit fluidity values that significantly deviate from the average.

Evaluating novel synthetic compounds active against Bacillus subtilis and Bacillus cereus spores using Live imaging with SporeTrackerX.

An empirical approach was taken to screen a novel synthetic compound library designed to be active against Gram-positive bacteria. We obtained five compounds that were active against spores from the model organism Bacillus subtilis and the food-borne pathogen Bacillus cereus during our population based experiments. Using single cell live imaging we were able to observe effects of the compounds on spore germination and outgrowth.

Different Amounts of DNA in Newborn Cells of Preclude a Role for the Chromosome in Size Control According to the "Adder" Model.

According to the recently-revived adder model for cell size control, newborn cells of will grow and divide after having added a constant size or length, , irrespective of their size at birth. Assuming exponential elongation, this implies that large newborns will divide earlier than small ones. The molecular basis for the constant size increment is still unknown.

Increasing protocol suitability for clinical trials in sub-Saharan Africa: a mixed methods study.

Background: The trial protocol is the most important document for clinical trials and describes not only the design and methodology of a study, but also all practical aspects. The suitability of the protocol has a direct impact on the execution and results of the trial. However, suitability is rarely addressed in trial practice and research.

The zebrafish embryo as a model to quantify early inflammatory cell responses to biomaterials.

To rapidly assess early inflammatory cell responses provoked by biomaterials in the full complexity of the living organism, we developed a zebrafish embryo model which allows real time analysis of these responses to biomaterial microspheres. Fluorescently labeled microspheres with different properties were injected into embryos of selected transgenic zebrafish lines expressing distinct fluorescent proteins in their neutrophils and macrophages. Recruitment of leukocytes and their interactions with microspheres were monitored using fluorescence microscopy.

"You can save time if…"-A qualitative study on internal factors slowing down clinical trials in Sub-Saharan Africa.

Background: The costs, complexity, legal requirements and number of amendments associated with clinical trials are rising constantly, which negatively affects the efficient conduct of trials. In Sub-Saharan Africa, this situation is exacerbated by capacity and funding limitations, which further increase the workload of clinical trialists. At the same time, trials are critically important for improving public health in these settings.

Asynchronous division by non-ring FtsZ in the gammaproteobacterial symbiont of Robbea hypermnestra.

The reproduction mode of uncultivable microorganisms deserves investigation as it can largely diverge from conventional transverse binary fission. Here, we show that the rod-shaped gammaproteobacterium thriving on the surface of the Robbea hypermnestra nematode divides by FtsZ-based, non-synchronous invagination of its poles-that is, the host-attached and fimbriae-rich pole invaginates earlier than the distal one. We conclude that, in a naturally occurring animal symbiont, binary fission is host-oriented and does not require native FtsZ to polymerize into a ring at any septation stage.

Intracellular pH Response to Weak Acid Stress in Individual Vegetative Bacillus subtilis Cells.

Unlabelled: Intracellular pH (pH) critically affects bacterial cell physiology. Hence, a variety of food preservation strategies are aimed at perturbing pH homeostasis. Unfortunately, accurate pH quantification with existing methods is suboptimal, since measurements are averages across populations of cells, not taking into account interindividual heterogeneity.

The Good Clinical Practice guideline and its interpretation - perceptions of clinical trial teams in sub-Saharan Africa.

Objectives: To explore the advantages and challenges of working with the Good Clinical Practice (GCP)-International Conference of Harmonization (ICH) E6 guideline and its interpretation from the perspective of clinical trial teams based in sub-Saharan Africa.

Methods: We conducted 60 key informant interviews with clinical trial staff at different levels in clinical research centres in Kenya, Ghana, Burkina Faso and Senegal and thematically analysed the responses.

Results: Clinical trial teams perceived working with ICH-GCP as highly advantageous and regarded ICH-GCP as applicable to their setting and efficiently applied.

When Phase Contrast Fails: ChainTracer and NucTracer, Two ImageJ Methods for Semi-Automated Single Cell Analysis Using Membrane or DNA Staining.

Within bacterial populations, genetically identical cells often behave differently. Single-cell measurement methods are required to observe this heterogeneity. Flow cytometry and fluorescence light microscopy are the primary methods to do this.

Quantifying the effect of sorbic acid, heat and combination of both on germination and outgrowth of Bacillus subtilis spores at single cell resolution.

Bacillus subtilis spores are a problem for the food industry as they are able to survive preservation processes. The spores often reside in food products, where their inherent protection against various stress treatments causes food spoilage. Sorbic acid is widely used as a weak acid preservative in the food industry.

Cell age dependent concentration of Escherichia coli divisome proteins analyzed with ImageJ and ObjectJ.

The rod-shaped Gram-negative bacterium Escherichia coli multiplies by elongation followed by binary fission. Longitudinal growth of the cell envelope and synthesis of the new poles are organized by two protein complexes called elongasome and divisome, respectively. We have analyzed the spatio-temporal localization patterns of many of these morphogenetic proteins by immunolabeling the wild type strain MC4100 grown to steady state in minimal glucose medium at 28°C.

Segregation of chromosome arms in growing and non-growing Escherichia coli cells.

In slow-growing Escherichia coli cells the chromosome is organized with its left (L) and right (R) arms lying separated in opposite halves of the nucleoid and with the origin (O) in-between, giving the pattern L-O-R. During replication one of the arms has to pass the other to obtain the same organization in the daughter cells: L-O-R L-O-R. To determine the movement of arms during segregation six strains were constructed carrying three colored loci: the left and right arms were labeled with red and cyan fluorescent-proteins, respectively, on loci symmetrically positioned at different distances from the central origin, which was labeled with green-fluorescent protein.