sporulation process
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2022 ◽  
Vol 12 ◽  
Author(s):  
Jackson Luu ◽  
Connor M. Mott ◽  
Olivia R. Schreiber ◽  
Holly M. Giovinco ◽  
Melanie Betchen ◽  
...  

Bacillus subtilis produces dormant, highly resistant endospores in response to extreme environmental stresses or starvation. These spores are capable of persisting in harsh environments for many years, even decades, without essential nutrients. Part of the reason that these spores can survive such extreme conditions is because their chromosomal DNA is well protected from environmental insults. The α/β-type small acid-soluble proteins (SASPs) coat the spore chromosome, which leads to condensation and protection from such insults. The histone-like protein HBsu has been implicated in the packaging of the spore chromosome and is believed to be important in modulating SASP-mediated alterations to the DNA, including supercoiling and stiffness. Previously, we demonstrated that HBsu is acetylated at seven lysine residues, and one physiological function of acetylation is to regulate chromosomal compaction. Here, we investigate if the process of sporulation or the resistance properties of mature spores are influenced by the acetylation state of HBsu. Using our collection of point mutations that mimic the acetylated and unacetylated forms of HBsu, we first determined if acetylation affects the process of sporulation, by determining the overall sporulation frequencies. We found that specific mutations led to decreases in sporulation frequency, suggesting that acetylation of HBsu at some sites, but not all, is required to regulate the process of sporulation. Next, we determined if the spores produced from the mutant strains were more susceptible to heat, ultraviolet (UV) radiation and formaldehyde exposure. We again found that altering acetylation at specific sites led to less resistance to these stresses, suggesting that proper HBsu acetylation is important for chromosomal packaging and protection in the mature spore. Interestingly, the specific acetylation patterns were different for the sporulation process and resistance properties of spores, which is consistent with the notion that a histone-like code exists in bacteria. We propose that specific acetylation patterns of HBsu are required to ensure proper chromosomal arrangement, packaging, and protection during the process of sporulation.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qiubin Huang ◽  
Zhen Zhang ◽  
Qing Liu ◽  
Fengying Liu ◽  
Yupeng Liu ◽  
...  

Abstract Background Bacillus cereus 0–9, a Gram-positive, endospore-forming bacterium isolated from healthy wheat roots in our previous research, is considered to be an effective biocontrol strain against several soil-borne plant diseases. SpoVG, a regulator that is broadly conserved among many Gram-positive bacteria, may help this organism coordinate environmental growth and virulence to survive. This study aimed to explore the multiple functions of SpoVG in B. cereus 0–9. Methods The gene knockout strains were constructed by homologous recombination, and the sporulation process of B. cereus 0–9 and its mutants were observed by fluorescence staining method. We further determined the spore yields and biofilm formation abilities of test strains. Transcriptional fusion strains were constructed by overlapping PCR technique, and the promoter activity of the target gene was detected by measuring its fluorescence intensity. The biofilm production and colonial morphology of B. cereus 0–9 and its mutants were determined to study the functions of the target genes, and the transcription level of the target gene was determined by qRT-PCR. Results According to observation of the sporulation process of B. cereus 0–9 in germination medium, SpoVG is crucial for regulating sporulation stage V of B. cereus 0–9, which is identical to that of Bacillus subtilis but differs from that of Bacillus anthracis. In addition, SpoVG could influence biofilm formation of B. cereus 0–9. The transcription levels of two genes closely related to biofilm-formation, sipW and calY, were downregulated in a ΔspoVG mutant. The role of SpoVG in regulating biofilm formation was further explored by deleting the genes abrB and sinR in the ΔspoVG mutant, respectively, generating the double mutant strains ΔspoVGΔabrB and ΔspoVGΔsinR. The phenotypes of these double mutants were congruent with those of the single abrB and sinR deletion strains, respectively, which showed increased biofilm formation. This indicated that spoVG was located upstream of abrB and sinR in the regulatory pathway of B. cereus biofilm formation. Further, the results of qRT-PCR and the luminescence intensity of transcriptional fusion strains indicated that spoVG gene deletion could inhibit the transcription of Spo0A. Conclusions SpoVG, an important regulator in the sporulation of B. cereus, is located upstream of Spo0A and participates in regulation of biofilm formation of B. cereus 0–9 through regulating the transcription level of spo0A. Sporulation and biofilm formation are crucial mechanisms by which bacteria respond to adverse conditions. SpoVG is therefore an important regulator of Spo0A and is crucial for both sporulation and biofilm formation of B. cereus 0–9. This study provides a new insight into the regulatory mechanism of environmental adaptation in bacteria and a foundation for future studies on biofilm formation of B. cereus.


2021 ◽  
Author(s):  
Linlin Zhao ◽  
Qing Liu ◽  
Qiubin Huang ◽  
Fengying Liu ◽  
Huiping Liu ◽  
...  

Abstract Tricarboxylic acid cycle (TCA cycle) is a central carbon metabolism pathway in prokaryotes and eukaryotes, and involved in matter metabolism and energy production. Isocitrate dehydrogenase (IDH), which is a key enzyme in the TCA cycle, participates in the formation of biofilms in Staphylococcus aureus by regulating the redox state inside the cell. At present, it remains to be clarified whether IDH is involved in the formation of Bacillus cereus biofilms. In this study, we found a gene icdH annotated as encoding IDH in the B. cereus genome, and cloned and expressed the protein encoded by this gene. The enzyme activity assay showed that the protein had IDH activity dependent on NADP+, indicating that this gene encoded an IDH. The mutant ΔicdH was obtained by gene knockout. Phenotypic analysis showed that the biofilm yield and sporulation rate of the mutant ΔicdH decreased. To reveal the role of IDH in biofilm formation, extracellular pH and citric acid content were measured. The results showed that a B.cereus 0–9 strain that lacked IDH exhibited accumulation of citric acid and acidification of the extracellular matrix. Given that citric acid is a metal chelator, the accumulation of citric acid may lead to a lack of metal ions in cells, resulting in reduced cell viability and affecting biofilm formation. Consistent with this hypothesis, the addition of excess Fe3+ restored biofilm formation in the mutant. These results suggest that IDH in B.cereus may regulate biofilm formation by modulating intracellular redox homeostasis. In addition, we found that the icdH deletion of B. cereus 0–9 resulted in the destruction of the stage I of sporulation process, and thus resulted in a reduced sporulation rate, which was significantly different from sporulation in B. subtilis caused by interruption of the stage I sporulation process due to icdH loss.


2020 ◽  
Vol 10 (9) ◽  
pp. 2927-2939
Author(s):  
Ana Lechuga ◽  
Cédric Lood ◽  
Margarita Salas ◽  
Vera van Noort ◽  
Rob Lavigne ◽  
...  

Abstract Bacillus thuringiensis is the most used biopesticide in agriculture. Its entomopathogenic capacity stems from the possession of plasmid-borne insecticidal crystal genes (cry), traditionally used as discriminant taxonomic feature for that species. As such, crystal and plasmid identification are key to the characterization of this species. To date, about 600 B. thuringiensis genomes have been reported, but less than 5% have been completed, while the other draft genomes are incomplete, hindering full plasmid delineation. Here we present the complete genome of Bacillus thuringiensis HER1410, a strain closely related to B. thuringiensis entomocidus and a known host for a variety of Bacillus phages. The combination of short and long-read techniques allowed fully resolving the genome and delineation of three plasmids. This enabled the accurate detection of an unusual location of a unique cry gene, cry1Ba4, located in a genomic island near the chromosome replication origin. Two megaplasmids, pLUSID1 and pLUSID2 could be delineated: pLUSID1 (368 kb), a likely conjugative plasmid involved in virulence, and pLUSID2 (156 kb) potentially related to the sporulation process. A smaller plasmidial prophage pLUSID3, with a dual lifestyle whose integration within the chromosome causes the disruption of a flagellar key component. Finally, phylogenetic analysis placed this strain within a clade comprising members from the B. thuringiensis serovar thuringiensis and other serovars and with B. cereus s. s. in agreement with the intermingled taxonomy of B. cereus sensu lato group.


2020 ◽  
Vol 37 (6) ◽  
pp. 1667-1678 ◽  
Author(s):  
Lei Shi ◽  
Abderahmane Derouiche ◽  
Santosh Pandit ◽  
Shadi Rahimi ◽  
Aida Kalantari ◽  
...  

Abstract Bacilli can form dormant, highly resistant, and metabolically inactive spores to cope with extreme environmental challenges. In this study, we examined the evolutionary age of Bacillus subtilis sporulation genes using the approach known as genomic phylostratigraphy. We found that B. subtilis sporulation genes cluster in several groups that emerged at distant evolutionary time-points, suggesting that the sporulation process underwent several stages of expansion. Next, we asked whether such evolutionary stratification of the genome could be used to predict involvement in sporulation of presently uncharacterized genes (y-genes). We individually inactivated a representative sample of uncharacterized genes that arose during the same evolutionary periods as the known sporulation genes and tested the resulting strains for sporulation phenotypes. Sporulation was significantly affected in 16 out of 37 (43%) tested strains. In addition to expanding the knowledge base on B. subtilis sporulation, our findings suggest that evolutionary age could be used to help with genome mining.


Author(s):  
N. V. Bogach ◽  
V. V. Skalchuk ◽  
I. A. Kushak

The purpose of work was to determine the effect of different concentrations of “Brovadez-plus” disinfectant solution on the sporulation process of mixed culture of eimerias oocysts of calves. Disinvasive activity of the drug “Brovadez-plus” was determined at concentrations of 1.5, 2, 3 and 3.5% for exposures of 3, 5 and 8 hours by irrigation of oocysts. The drug “Brovadez-plus’ at 2% concentration for 3 hours exposure showed an eimeriostatic effect at the level of 29.9 ± 1.4%. At 5 hours exposure, sporogonia did not undergo 51.1 ± 0.5% oocysts, and at 8 hours exposure 64.4 ± 2.2% eimerias oocysts of calves. When using 3% concentration of “Brovadez-plus” solution for 3 hours, sporulation process did not take place in 57.8 ± 0.6% eimerias oocysts, 2.7 ± 0.9% oocysts completed sporulation and 19.6 ± 0.9 % — the sporulation was delayed. The best results were obtained with the use of a 3% solution at an exposure of 5 and 8 hours. The sporogony process did not occur in 96.6 ± 1.2% and 98.2 ± 0.8% of oocysts of eimerias. When using “Brovadez-plus” disinfectant at a concentration of 3.5% at exposure for 3 hours sporogonia did not pass in 78.5 ± 1.1% of eimerias oocysts, at exposure for 5 hours in 96.8 ± 2.1% of eimerias oocysts at exposure 8 hours in 99.1 ± 2.4% of eimerias oocysts of calves. Thus, experimental studies have shown that the drug “Brovadez-plus”, when used in 3% and 3.5% concentrations, has a high level of disinvasive properties relative to eimerias oocysts of calves. Experimental studies have established that the detrimental effect on eimerias oocysts is directly proportional to the duration of their contact and the concentration of the working solution of the studied drug. When using 3% and 3.5% concentrations of “Brovades-plus” disinfectant at an exposure of 5 and 8 hours in 99.1 ± 2.4% of eimerias oocysts of calves, the process of sporogony did not occur


2018 ◽  
Vol 20 (3) ◽  
pp. 43-50
Author(s):  
Rita María Marín Naranjo MQC, MSc

The Trigeminal Neuralgia (TN) is described as  neuropathic pain at the orofacial level, characterized by unbearable pain that can last from a few seconds to several minutes. The different treatments used for these patients are to numb the nerve, surgical, pharmacological, and the administration at extra and intraoral level of botulinum toxin, which is a neurotoxin produced in cultures of the bacterium Clostridium botulinum in a natural way; in the sporulation process are 7 subtypes being the subtype A the most used in neurological problems. The botulinum toxin acts as a neuromuscular blocker, by inhibiting the release of acetylcholine at the synaptic space, which is an important neurotransmitter to produce local muscle relaxation, and the patients report reductions in the frequency and intensity of pain with minimal side effects. The injection of botulinum toxin produces an effective pain reduction of neuropathic origin in the hyperalgesic tissue and is used as adjuvant therapy when oral medications do not give adequate control of pain. Over time it is expected to reduce the drugs as the patient tells that the pain has decreased or is being controlled. Patients are indicated the variation of time in which they can obtain relief of their pain. In patients with uncontrolled pain of the trigeminal nerve, the toxin is placed extraoral in the orofacial region with high effectiveness, but there is a lack of studies on the administration in the intraoral submucosal.


2018 ◽  
Author(s):  
Emilie Gauvry ◽  
Anne-Gabrielle Mathot ◽  
Olivier Couvert ◽  
Ivan Leguérinel ◽  
Matthieu Jules ◽  
...  

AbstractBacterial spores are formed within vegetative cells as thick-walled bodies resistant to physical and chemical treatments which allow the persistence and dissemination of the bacterial species. Spore-forming bacteria are natural contaminants of food raw materials and sporulation can occur in many environments from farm to fork. In order to predict spore formation over time, we developed a model that describes both the kinetics of growth and the differentiation of vegetative cells into spores. The model includes a classical growth model with the addition of only two sporulation-specific parameters: the probability of each vegetative cell to sporulate, and the time needed to form a spore once the cell is committed to sporulation. The growth-sporulation model was evaluated using the spore-forming, Gram positive bacterium,Bacillus subtilisand the biological meaning of the sporulation-specific parameters was validated using a derivative strain that produces the green fluorescent protein as a marker of sporulation initiation. The model accurately describes the growth and the sporulation kinetics in different environmental conditions and further provides valuable, physiological information on the temporal abilities of vegetative cells to differentiate into spores.ImportanceThe growth-sporulation model we developed accurately describes growth and sporulation kinetics. It describes the progressive transition from vegetative cells to spores with sporulation parameters which are meaningful and relevant to the sporulation process. The first parameter is the mean time required for a vegetative cell to differentiate into a spore (i.e. the duration of the sporulation process). The second sporulation parameter is the probability of each vegetative cell forming a spore over time. This parameter assesses how efficient the sporulation process is, how fast vegetative cells sporulate and how synchronous the bacterial population is for sporulation. The model constitutes a very interesting tool to describe the growth and the sporulation kinetics in different environmental conditions and it provides qualitative information on the sporulation of a bacterial population over time.


2018 ◽  
Vol 20 (83) ◽  
pp. 401-404
Author(s):  
A.V. Berezovskyi ◽  
A.L. Nechiporenko

Parasitosis occupies the third place in the world аmong animal diseases. Prevention of helminthoses in industrial poultry farming is based on a complex of measures aimed at effective neutralization of pathogens at different stages of their development. One of the most effective of them is dezinvasion. Dezinvasion in the industrial zones of poultry farms must be subject to premises and their equipment, inventory and all bird care items, walking grounds, poultry droppings. Determination of the resistance of the causative agent of poultry eimeriosis to the action of disinfectant «Deszan». The diagnosis of eimeriosis was established according to the results of laboratory studies of poultry droppings by the method of Füleborn. As the active substance, the preparation «Deszan» was used in a concentration of 2.0 and 3.0% with exposures of 2, 3 and 4 hours. When studying the influence of the disinfectant on the eimeria of the Eimeria tenella bird, it was found that when the oocyst is treated with the «Dezsan» preparation at a concentration of 2.0% with 2 hours exposure, the sporulation process stops in the oocysts. The observation was carried out for 5 days, however, no external changes were observed in the eimerias. When oocysts of coccidia were treated with a solution of the preparation «Deszan» at a concentration of 2.0 and 3.0%, during 3 hours of exposure, the sporulation process and compression of the cytoplasm were observed. The exposure of 3–4 hours observed in the field of view of the microscope rupture of shells and fragments of destroyed oocysts of coccidia. The disinfection effect of the «Deszan» preparation was established at a concentration of 2.0% with an exposure of 4 hours and 3.0% with an exposure of 3 hours to the ovine’s of the poultry Eimeria tenella. After 2 hours of exposure in oocysts, there was a decrease in sporulation and morphological changes in their cytoplasm.


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