A single point mutation in hmgA leads to melanin accumulation in Bacillus thuringiensis BMB181

Tan, Tong-tong; Zhang, Xudong; Miao, Zhen; Yu, Ying; Du, Siling; Hou, Xiaoyue; Cai, Jin

doi:10.1016/j.enzmictec.2018.10.007

Cited by 15 publications

(13 citation statements)

References 21 publications

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“…The tyrosinase enzyme is a fundamental enzyme principally used in melanin production and in the different pharmaceutical industry. Till this moment there are scarce publications on bacterial tyrosinases and there is not enough information concerning the structure and characterization of the yielded melanin [15]. Within this context, one bacterium was isolated from the surface of petroleum pipes Maracopara, France at 1% O 2 .…”

Section: Resultsmentioning

confidence: 99%

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Optimization of Bacillus licheniformis MAL tyrosinase: in vitro anticancer activity for brown and black eumelanin

Shalaby

Ragab

Helal

et al. 2019

Heliyon

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The influence of tyrosinase in catalyzes/stimulates the eumelanin production was studied. Accordingly, bacterial sp. was isolated and identified as Bacillus licheniformis based on 16S rRNA . It could grow and gave monophenolase and diphenolase productivity in medium contained tyrosin and Cu 2+ only. The tyrosinase enzymes were optimized by studying different environmental and nutritional factors. The maximum monophenolase and diphenolase productivity were obtained at 60 °C, pH9, Cu 2+ (0.01g), liver extract (1 g/L) and the oxygen level fixed at 20%. Also, the mannose as a carbon source increased the monophenolase production 6.2 times. For the first time, two types of eumelanin were extracted by hydrochloric acid treatment. The black and brown eumelanin weighed (0.1 g/100 mL and 0.7 g/100 mL respectively) and characterized by using FTIR and UV/Vis spectroscopy techniques. Their morphological structure and its elemental composition were characterized by SEM and EDAX respectively. The black melanin showed promising anticancer activity towards HEPG-2 and HCT-116 cell lines with IC 50 values (6.15, 5.54 μg) compared to Doxorubicin (4.05, 4.45 μg) respectively.

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Section: Resultsmentioning

confidence: 99%

“…In addition, the determination of the ratio of the various units found in melanin is not yet available. The molecular structure and organization of melanin are complicated and not completely known [14, 15]. A great number of investigations on melanin have been done, but untill now it is still not well understood.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Bacillus licheniformis MAL tyrosinase: in vitro anticancer activity for brown and black eumelanin

Shalaby

Ragab

Helal

et al. 2019

Heliyon

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“…also worked in B. thuringiensis L-7601 (Cao et al, 2018). Subsequently, Tan et al constructed an hmgA-deletion mutant from strain BMB171, which gained the ability to produce pyomelanin (Tan et al, 2019). Although these strains can produce melanin, they are crystalliferous with no insecticidal property, thus having limited application value.…”

Section: Introductionmentioning

confidence: 99%

Creation of an Industrial Bacillus thuringiensis Strain With High Melanin Production and UV Tolerance by Gene Editing

et al. 2022

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Bacillus thuringiensis produces insecticidal crystal proteins (ICPs) which exhibit strong insecticidal toxicity. But when used in the field, ICPs would be destroyed by ultraviolet (UV) radiation in sunlight, thus decreasing the insecticidal activity and shortening the persistence. To improve the duration of B. thuringiensis preparations, we endowed a highly toxic industrial B. thuringiensis HD-1 with UV tolerance by making it produce melanin, a pigment that absorbs UV radiation. In B. thuringiensis, melanin is derived from homogentisate (HGA), an intermediate in the tyrosine pathway. And the absence of homogentisate-1,2-dioxygenase (HmgA) will lead to the formation of melanin. In this study, we used the CRISPR/Cas9 system to knock out the hmgA gene and obtained a melanin-producing mutant HD-1-ΔhmgA from strain HD-1. The melanin yield by mutant HD-1-ΔhmgA reached 3.60 mg/mL. And the anti-UV test showed that melanin serves as a protection to both the organism and the ICPs. After UV irradiation for 3 h, mutant HD-1-ΔhmgA still had an 80% insecticidal activity against the cotton bollworm, Helicoverpa armigera, while the control line only had about 20%. This study creates a light-stable biopesticide prototype based on a classic industrial strain that can be applied directly and takes the melanin-producing strain as a concept to improve the preparation validity.

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“…To date, the CRISPR/Cas9 system has only been used to construct B . thuringiensis mutants, and no related work has been reported in B. anthracis or B. cereus (Guo et al, 2019; Tan et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Genome Engineering in Bacillus anthracis and Bacillus cereus Using the CRISPR/Cas9 System

Wang¹,

Wang²,

Wang³

et al. 2019

Front. Microbiol.

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Genome editing is an effective tool for the functional examination of bacterial genes and for live attenuated vaccine construction. Here, we report a method to edit the genomic DNA of Bacillus anthracis and Bacillus cereus using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)9 system. Using two prophages in B. anthracis as targets, large-fragment deletion mutants were achieved with rates of 100 or 20%. In B. cereus, we successfully introduced precise point mutations into plcR, with phenotypic assays showing that the resulting mutants lost hemolytic and phospholipase enzyme activities similar to B. anthracis, which is a natural plcR mutant. Our study indicates that CRISPR/Cas9 is a powerful genetic tool for genome editing in the Bacillus cereus group, and can efficiently modify target genes without the need for residual foreign DNA such as antibiotic selection markers. This system could be developed for use in the generation of marker-free live anthrax vaccines or for safer construction of microbiological candidate-based recombinant B. cereus.

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A single point mutation in hmgA leads to melanin accumulation in Bacillus thuringiensis BMB181

Cited by 15 publications

References 21 publications

Optimization of Bacillus licheniformis MAL tyrosinase: in vitro anticancer activity for brown and black eumelanin

Optimization of Bacillus licheniformis MAL tyrosinase: in vitro anticancer activity for brown and black eumelanin

Creation of an Industrial Bacillus thuringiensis Strain With High Melanin Production and UV Tolerance by Gene Editing

Highly Efficient Genome Engineering in Bacillus anthracis and Bacillus cereus Using the CRISPR/Cas9 System

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