Crystal protein synthesis is dependent on early sporulation gene expression inBacillus sphaericus

Biotechnological Potential of Microorganisms for Mosquito Population Control and Reduction in Vector Competence

Mosquitoes transmit pathogens that cause human diseases such as malaria, dengue fever, chikungunya, yellow fever, Zika fever, and filariasis. Biotechnological approaches using microorganisms have a significant potential to control mosquito populations and reduce their vector competence, making them alternatives to synthetic insecticides. Ongoing research has identified many microorganisms that can be used effectively to control mosquito populations and disease transmission. However, the successful implementation of these newly proposed approaches requires a thorough understanding of the multipronged microorganism-mosquito-pathogen-environment interactions. Although much has been achieved in discovering new entomopathogenic microorganisms, antipathogen compounds, and their mechanisms of action, only a few have been turned into viable products for mosquito control. There is a discrepancy between the number of microorganisms with the potential for the development of new insecticides and/or antipathogen products and the actual available products, highlighting the need for investments in the intersection of basic research and biotechnology.

Synthesis of C 3-symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step

We demonstrate a new synthetic strategy toward star-shaped C₃-symmetric molecules containing α-amino acid (AAA) derivatives and dipeptides. In this regard, trimerization and Negishi cross-coupling reactions are used as the key steps starting from readily available 4’-iodoacetophenone and L-serine. These C₃-symmetric molecules containing AAA moieties are useful to design new ligands suitable for asymmetric synthesis and peptide dendrimers.

Synthesis and Photophysical Properties of C 3-Symmetric Star-Shaped Molecules Containing Heterocycles Such as Furan, Thiophene, and Oxazole

We report simple strategies to synthesize star-shaped molecules containing different heterocycles integrated with a number of variations. Here, cyclotrimerization, Vilsmeier-Haack reaction, Suzuki-Miyaura cross-coupling, and Van Leusen oxazole synthesis have been used as key steps to introduce diverse five-membered heterocycles such as furan, thiophene, and oxazole. More importantly, readily available starting materials such as thiophene, 2-formyl furan, and 2-acetyl furan were utilized. Also, the fluorescent behavior of these π-conjugated systems was studied. C ₃-Symmetric molecules containing furan moieties show a stronger fluorescence than thiophene-containing star-shaped compounds.

Anticancer Activity of Binary Toxins from Lysinibacillus sphaericus IAB872 against Human Lung Cancer Cell Line A549

The inhibitory effect of binary toxic (Bin) protein produced by Lysinibacillus sphaericus IAB872 on cell proliferation of human lung, liver, stomach and cervical tumor cell lines was assessed using MTT assay. The effect of Bin protein on A549 cell proliferation, apoptosis, cell cycle, migration and invasion were examined by MTT assay, Western blotting, Immunocytochemical staining, flow cytometry assay and wound-healing assay. Results showed that Bin protein inhibits proliferation of a range of human cancer cells in vitro. The anti-proliferative effect of Bin is associated with cell apoptosis as a result of an increased ratio of cellular Bax/bcl-2, up-regulated CyclinB1and down-regulated Cdc25c expression, and its anti-proliferative action was associated with cell cycle arrest in the G2/M-phase. Bin protein could promote apoptosis and inhibit motility and invasion of A549 cancer cells. The anti-proliferative effect of Bin protein was associated with the induction of apoptotic cell death and cell cycle disruption. These results show that Bin protein has the potential to be developed as a chemotherapeutic agent by induction of human tumor cell apoptosis.

The bacterium, Lysinibacillus sphaericus, as an insect pathogen

Since the first bacteria with insecticidal activity against mosquito larvae were reported in the 1960s, many have been described, with the most potent being isolates of Bacillus thuringiensis or Lysinibacillus sphaericus (formerly and best known as Bacillus sphaericus). Given environmental concerns over the use of broad spectrum synthetic chemical insecticides and the evolution of resistance to these, industry placed emphasis on the development of bacteria as alternative control agents. To date, numerous commercial formulations of B. thuringiensis subsp. israelensis (Bti) are available in many countries for control of nuisance and vector mosquitoes. Within the past few years, commercial formulations of L. sphaericus (Ls) have become available. Because Bti has been in use for more than 30 years, its properties are well know, more so than those of Ls. Thus, the purpose of this review is to summarise the most critical aspects of Ls and the various proteins that account for its insecticidal properties, especially the mosquitocidal activity of the most common isolates studied. Data are reviewed for the binary toxin, which accounts for the activity of sporulated cells, as well as for other toxins produced during vegetative growth, including sphaericolysin (active against cockroaches and caterpillars) and the different mosquitocidal Mtx and Cry toxins. Future studies of these could well lead to novel potent and environmentally compatible insecticidal products for controlling a range of insect pests and vectors of disease.

Cloning, functional characterization, and mode of action of a novel insecticidal pore-forming toxin, sphaericolysin, produced by Bacillus sphaericus

An insecticidal protein produced by Bacillus sphaericus A3-2 was purified to elucidate its structure and mode of action. The active principle purified from the culture broth of A3-2 was a protein with a molecular mass of 53 kDa that rapidly intoxicated German cockroaches (Blattela germanica) at a dose of about 100 ng when injected. The insecticidal protein sphaericolysin possessed the undecapeptide motif of cholesterol-dependent cytolysins and had a unique N-terminal sequence. The recombinant protein expressed in Escherichia coli was equally as potent as the native protein. Sphaericolysin-induced hemolysis resulted from the protein's pore-forming action. This activity as well as the insecticidal activity was markedly reduced by a Y159A mutation. Also, coapplication of sphaericolysin with cholesterol abolished the insecticidal action, suggesting that cholesterol binding plays an important role in insecticidal activity. Sphaericolysin-lysed neurons dissociated from the thoracic ganglia of the German cockroaches. In addition, sphaericolysin's activity in ganglia was suppressed by the Y159A mutation. The sphaericolysin-induced damage to the cockroach ganglia was greater than the damage to the ganglia of common cutworms (Spodoptera litura), which accounts, at least in part, for the higher sensitivity to sphaericolysin displayed by the cockroaches than that displayed by cutworms.

Negative regulation of Bacillus anthracis sporulation by the Spo0E family of phosphatases

The initiation of sporulation in Bacillus species is controlled by the phosphorelay signal transduction system. Multiple regulatory elements act on the phosphorelay to modulate the level of protein phosphorylation in response to cellular, environmental, and metabolic signals. In Bacillus anthracis nine possible histidine sensor kinases can positively activate the system, while two response regulator aspartyl phosphate phosphatases of the Rap family negatively impact the pathway by dephosphorylating the Spo0F intermediate response regulator. In this study, we have characterized the B. anthracis members of the Spo0E family of phosphatases that specifically dephosphorylate the Spo0A response regulator of the phosphorelay and master regulator of sporulation. The products of four genes were able to promote the dephosphorylation of Spo0A approximately P in vitro. The overexpression of two of these B. anthracis Spo0E-like proteins from a multicopy vector consistently resulted in a sporulation-deficient phenotype. A third gene was found to be not transcribed in vivo. A fourth gene encoded a prematurely truncated protein due to a base pair deletion that nevertheless was subject to translational frameshift repair in an Escherichia coli protein expression system. A fifth Spo0E-like protein has been structurally and functionally characterized as a phosphatase of Spo0A approximately P by R. N. Grenha et al. (J. Biol. Chem. 281:37993-38003, 2006). We propose that these proteins may contribute to maintain B. anthracis in the transition phase of growth during an active infection and therefore contribute to the virulence of this organism.