Identification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a binding protein for a 68-kDa Bacillus thuringiensis parasporal protein cytotoxic against leukaemic cells

Comparative genome analysis of Bacillus thuringiensis strain HD521 and HS18-1

Bacillus thuringiensis (Bt) is an important biological insecticide used to management of different agricultural pests by producing toxic parasporal crystals proteins. Strain HD521 has an antagonistic effect against Rhizoctonia solani AG1IA, the causal agent of rice sheath blight. This strain with three cry7 genes can the formation of bipyramidal parasporal crystals (BPCs). BPCs are used for insecticidal activities against Henosepilachna vigintioctomaculata larva (Coleoptera). Strain HS18-1 contains different types of BPCs encoding genes and has effective toxicity for Lepidoptera and Diptera insects. Here we report the whole genome sequencing and assembly of HD521 and HS18-1 strains and analyzed the genome constitution covering virulence factors, types of plasmid, insertion sequences, and prophage sequences. The results showed that the genome of strain HD521 contains a circular chromosome and six circular plasmids, encoding eight types of virulence protein factors [Immune Inhibitor A, Hemolytic Enterotoxin, S-layer protein, Phospholipase C, Zwittermicin A-resistance protein, Metalloprotease, Chitinase, and N-acyl homoserine lactonase (AiiA)], four families of insertion sequence, and comprises six pro-phage sequences. The genome of strain HS18-1 contains one circular chromosome and nine circular plasmids, encoding five types of virulence protein factors [Hemolytic Enterotoxin, S-layer protein, Phospholipase C, Chitinase, and N-acyl homoserine lactonase (AiiA)] and four families of insertion sequence, and comprises of three pro-phage sequences. The obtained results will contribute to deeply understand the B. thuringiensis strain HD521 and HS18-1 at the genomic level.

Parasporin A13-2 of Bacillus thuringiensis Isolates from the Papaloapan Region (Mexico) Induce a Cytotoxic Effect by Late Apoptosis against Breast Cancer Cells

The protein A13-2 was obtained from Bacillus thuringiensis strains isolated from the Papaloapan watershed region (Oaxaca, Mexico). The cytotoxic activity of parasporal inclusions was studied against breast cancer cell line (MCF-7) and normal cell (human peripheral blood mononuclear cells). The MTT, the formation of reactive species, nitric oxide, free cell DNA, and the type of death cellular were assessed. The protein A13-2 shows the highest cytotoxic activity against MCF-7 (13% cell viability at 6 µg/mL), the extracellular DNA increases, and it shows no stress for reactive species or nitric oxide. Besides, the A13-2 parasporin shows no toxicity to peripheral blood mononuclear cells, and it does not generate changes in nitric oxide levels or free cell DNA. Due to that, the cytotoxic effect of A13-2 was specific for MCF-7, and it does not affect normal cells. According to microscopy and flow cytometry, A13-2 parasporin leads to the death of MCF-7 cells by late apoptosis together with necrosis and without allowing the triggering of the survival mechanisms. When analyzed together, our results show for the first time that the A13-2 protein isolated from Mexican strains of B. thuringiensis preferentially kills MCF- 7 (cancer cells) over HEK 293 and PBMC cell lines (normal cells), thus representing a promising alternative for the treatment of cancer breast.

Crystal Protein of a Novel Bacillus thuringiensis Strain Inducing Cell Cycle Arrest and Apoptotic Cell Death in Human Leukemic Cells

Parasporal inclusions of a native non haemolytic Bacillus thuringiensis strain KAU 59 was screened for its cytotoxicity against human lymphocytic leukemic cell line jurkat and normal human lymphocytes. The cytotoxicity of proteinase activated and non activated solubilised parasporal inclusions against both cell lines was assessed by Cell Titer 96 Aqueous Non Radioactive Cell Proliferation Assay Kit using MTS. The 50 per cent effective concentration (EC₅₀) values were deduced from log probit analysis at 48 h. Morphological changes associated with cytotoxicity were evaluated and molecular mechanisms of cell death were elucidated by TUNEL assay at 48 h post-inoculation. The fluorescence assisted cell sorting was done in the flow cytometer to assess the stage of cell cycle arrest. Relative quantification of caspase-3 expression in Jurkat cells treated with parasporal inclusion protein of KAU 59 was done by qRTPCR The results indicated that the protein was cytotoxic to jurkat cells at the same time non toxic to normal lymphocytes. Cytotoxicity was evident only after proteolytic activation. Apoptotic cell death was confirmed in the protein treated cells by TUNEL Assay and also up regulated caspase-3 gene expression (P < 0.001). S phase cell cycle arrest was confirmed by and fluorescence associated cell sorting.

TOXINAS DE Bacillus thuringiensis CON ACTIVIDAD ANTICANCERÍGENA: PARASPORINAS

Las toxinas Cry de Bacillus thuringiensis (Bt) han sido reconocidas por su acción biocontroladora contra insectos plaga. Recientemente se ha descrito que algunas cepas de Bt presentan proteínas que no presentan actividad insecticida, pero al ser enfrentadas a líneas celulares de cáncer de diferentes tipos han demostrado actividad citotóxica. Estas proteínas han sido denominadas parasporinas (PS) y surgen como una potencial alternativa para el tratamiento del cáncer debido a que presentan alta citotoxicidad hacia diferentes líneas celulares cancerígenas, y baja o nula citotoxicidad hacia células normales.

GAPDH rs1136666 SNP indicates a high risk of Parkinson's disease

BACKGROUND

Development of Parkinson's disease (PD) is attributed to both genetic and environmental factors. Furthermore,GAPDH may play a key role in the development of neurodegenerative disease. Examination of genetic polymorphism in patients with sporadic PD will help uncover the mechanisms of PD pathogenesis and provide new insights into the treatment of PD.

METHODS AND RESULTS

The SNaPshot method was applied to determine the gene sequences in 265 patients with idiopathic PD and 269 control cases (sex- and age-matched). The rs1136666 polymorphism of GAPDH was determined to be closely associated with PD. Subsequently, the CC genotype of the rs1136666 fragment was transfected into SH-SY5Y cells via a plasmid. The genetic expression of rs1136666 CC could induce SH-SY5Y cell injury and apoptosis via regulation of the oxidant-antioxidant and apoptosis-antiapoptosis balance. rs1136666 CC of the GAPDH had a pro-apoptotic effect similar to that of rotenone, and combination of the rs1136666 CC genetic variation and the rotenone neurotoxic effect could aggravate oxidative stress, cell injury, and apoptosis better than either single treatment alone.

CONCLUSION

This study confirmed that the rs1136666 CC allele of theGAPDH increased the risk of PD, particularly in older male patients.

Bacillus thuringiensis: a successful insecticide with new environmental features and tidings

Bacillus thuringiensis (Bt) is known as the most successful microbial insecticide against different orders of insect pests in agriculture and medicine. Moreover, Bt toxin genes also have been efficiently used to enhance resistance to insect pests in genetically modified crops. In light of the scientific advantages of new molecular biology technologies, recently, some other new potentials of Bt have been explored. These new environmental features include the toxicity against nematodes, mites, and ticks, antagonistic effects against plant and animal pathogenic bacteria and fungi, plant growth-promoting activities (PGPR), bioremediation of different heavy metals and other pollutants, biosynthesis of metal nanoparticles, production of polyhydroxyalkanoate biopolymer, and anticancer activities (due to parasporins). This review comprehensively describes recent advances in the Bt whole-genome studies, the last updated known Bt toxins and their functions, and application of cry genes in plant genetic engineering. Moreover, the review thoroughly describes the new features of Bt which make it a suitable cell factory that might be used for production of different novel valuable bioproducts.

Glutamate transporter type 3 regulates mouse hippocampal GluR1 trafficking

BACKGROUND

Rapid trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) to the plasma membrane is considered a fundamental biological process for learning and memory. GluR1 is an AMPAR subunit. We have shown that mice with knockout of excitatory amino acid transporter type 3 (EAAT3), a neuronal glutamate transporter, have impaired learning and memory. The mechanisms for this impairment are not known and may be via regulation of AMPAR trafficking.

METHODS

Freshly prepared 300μm coronal hippocampal slices from wild-type or EAAT3 knockout mice were incubated with or without 25mM tetraethylammonium for 10min. The trafficking of GluR1, an AMPAR subunit, to the plasma membrane and its phosphorylation were measured.

RESULTS

Tetraethylammonium increased the trafficking of GluR1 and EAAT3 to the plasma membrane in the wild-type mouse hippocampal slices but did not cause GluR1 trafficking in the EAAT3 knockout mice. Tetraethylammonium also increased the phosphorylation of GluR1 at S845, a protein kinase A (PKA) site, in the wild-type mice but not in the EAAT3 knockout mice. The PKA antagonist KT5720 attenuated tetraethylammonium-induced GluR1 phosphorylation and trafficking in the wild-type mice. The PKA agonist 6-BNz-cAMP caused GluR1 trafficking to the plasma membrane in the EAAT3 knockout mice. In addition, EAAT3 was co-immunoprecipitated with PKA.

CONCLUSIONS

These results suggest that EAAT3 is upstream of PKA in a pathway to regulate GluR1 trafficking.

GENERAL SIGNIFICANCE

Our results provide initial evidence for the involvement of EAAT3 in the biochemical cascade of learning and memory.

On the functional diversity of glyceraldehyde-3-phosphate dehydrogenase: biochemical mechanisms and regulatory control

BACKGROUND

New studies provide evidence that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is not simply a classical glycolytic protein of little interest. Instead, it is a multifunctional protein with significant activity in a number of fundamental cell pathways. GAPDH is a highly conserved gene and protein, with a single mRNA transcribed from a unique gene. Control mechanisms must exist which regulate its functional diversity.

SCOPE OF REVIEW

This review focuses on new, timely studies defining not only its diverse activities but also those which define the regulatory mechanisms through which those functions may be controlled. The reader is referred to the author's prior review for the consideration of past reports which first indicated GAPDH multiple activities (Sirover, Biochim. Biophys. Acta 1432 (1999) 159-184.)

CONCLUSIONS

These investigations demonstrate fundamental roles of GAPDH in vivo, dynamic changes in its subcellular localization, and the importance of posttranslational modifications as well as protein:protein interactions as regulatory control mechanisms.

GENERAL SIGNIFICANCE

GAPDH is the prototype "moonlighting" protein which exhibits activities distinct from their classically identified functions. Their participation in diverse cell pathways is essential. Regulatory mechanisms exist which control those diverse activities as well as changes in their subcellular localization as a consequence of those new functions.