Bifunctional TaqII restriction endonuclease: redefining the prototype DNA recognition site and establishing the Fidelity Index for partial cleaving

<p>Abstract</p> <p>Background</p> <p>The TaqII enzyme is a member of the <it>Thermus </it>sp. enzyme family that we propounded previously within Type IIS restriction endonucleases, containing related thermophilic bifunctional endonucleases-methyltransferases from various <it>Thermus </it>sp.: TaqII, Tth111II, TthHB27I, TspGWI, TspDTI and TsoI. These enzymes show significant nucleotide and amino acid sequence similarities, a rare phenomenon among restriction endonucleases, along with similarities in biochemical properties, molecular size, DNA recognition sequences and cleavage sites. They also feature some characteristics of Types I and III.</p> <p>Results</p> <p>Barker et al. reported the Type IIS/IIC restriction endonuclease TaqII as recognizing two distinct cognate site variants (5'-GACCGA-3' and 5'-CACCCA-3') while cleaving 11/9 nucleotides downstream. We used four independent methods, namely, shotgun cloning and sequencing, restriction pattern analysis, digestion of particular custom substrates and GeneScan analysis, to demonstrate that the recombinant enzyme recognizes only 5'-GACCGA-3' sites and cleaves 11/9 nucleotides downstream. We did not observe any 5'-CACCCA-3' cleavage under a variety of conditions and site arrangements tested. We also characterized the enzyme biochemically and established new digestion conditions optimal for practical enzyme applications. Finally, we developed and propose a new version of the Fidelity Index - the Fidelity Index for Partial Cleavage (FI-PC).</p> <p>Conclusions</p> <p>The DNA recognition sequence of the bifunctional prototype TaqII endonuclease-methyltransferase from <it>Thermus aquaticus </it>has been redefined as recognizing only 5'-GACCGA-3' cognate sites. The reaction conditions (pH and salt concentrations) were designed either to minimize (pH = 8.0 and 10 mM ammonium sulphate) or to enhance star activity (pH = 6.0 and no salt). Redefinition of the recognition site and reaction conditions makes this prototype endonuclease a useful tool for DNA manipulation; as yet, this enzyme has no practical applications. The extension of the Fidelity Index will be helpful for DNA manipulation with enzymes only partially cleaving DNA.</p

Enzymatic synthesis of long double-stranded DNA labeled with haloderivatives of nucleobases in a precisely pre-determined sequence

<p>Abstract</p> <p>Background</p> <p>Restriction endonucleases are widely applied in recombinant DNA technology. Among them, enzymes of class IIS, which cleave DNA beyond recognition sites, are especially useful. We use BsaI enzyme for the pinpoint introduction of halogen nucleobases into DNA. This has been done for the purpose of anticancer radio- and phototherapy that is our long-term objective.</p> <p>Results</p> <p>An enzymatic method for synthesizing long double-stranded DNA labeled with the halogen derivatives of nucleobases (Hal-NBs) with 1-bp accuracy has been put forward and successfully tested on three different DNA fragments containing the 5-bromouracil (5-BrU) residue. The protocol assumes enzymatic cleavage of two Polymerase-Chain-Reaction (PCR) fragments containing two recognition sequences for the same or different class IIS restriction endonucleases, where each PCR fragment has a partially complementary cleavage site. These sites are introduced using synthetic DNA primers or are naturally present in the sequence used. The cleavage sites are not compatible, and therefore not susceptible to ligation until they are partially filled with a Hal-NB or original nucleobase, resulting in complementary cohesive end formation. Ligation of these fragments ultimately leads to the required Hal-NB-labeled DNA duplex. With this approach, a synthetic, extremely long DNA fragment can be obtained by means of a multiple assembly reaction (n × maximum PCR product length: n × app. 50 kb).</p> <p>Conclusions</p> <p>The long, precisely labeled DNA duplexes obtained behave in very much the same manner as natural DNA and are beyond the range of chemical synthesis. Moreover, the conditions of synthesis closely resemble the natural ones, and all the artifacts accompanying the chemical synthesis of DNA are thus eliminated. The approach proposed seems to be completely general and could be used to label DNA at multiple pre-determined sites and with halogen derivatives of any nucleobase. Access to DNAs labeled with Hal-NBs at specific position is an indispensable condition for the understanding and optimization of DNA photo- and radio-degradation, which are prerequisites for clinical trials of Hal-NBs in anticancer therapy.</p

Microbiological characterization of psychro-mezo-thermophilic endospore-producing Bacillus species isolated from industrial probiotics particles

Probiotics are either bacteria which naturally and steadily reside in the human gastrointestinal tract (GIT), such as certain Lactobacillus sp., or are bimodal, i.e. capable of proliferation both in GIT, as well as in the external environment, these include certain Bacillus sp. In this report we characterize a mixture of Bacillus species present in widely used commercial preparations, present in lyophilized particles. Four endospore-producing species were detected through MALDI TOF mass spectrometry and microbiological analyses: Bacillus mojavensis, Bacillus vallismortis, Bacillus pumilus and Bacillus subtilis. They exhibit an exceptionally wide range of growth temperature: from 20°C to 58oC, thus they are environmentally multi-modal and cover areas occupied both by psychrophiles, mesophiles and thermophiles. Thus, they are exceedingly adaptive to different environments and able to proliferate in highly diverse niches, including the human GIT. Considering that all of the four characterized species have similar characteristics, including endospore production and growth in a wide range of pH, which allows them to survive in transiently low pH during GIT passage, as well as their widespread occurrence in the environment, it is very likely that they have evolved along with mammals as their natural, transient or permanent, GIT inhabitants, though they are not limited to this niche. Acknowledgments: the project was supported GRUPA INCO S.A., ul. Wspolna 25, 00-519 Warsaw, Poland, NCBiR grant no POIG.01.04.00-02-181/13 and by University of Gdansk task funds no. DS 530-8645-D509-15

Construction of bionanoparticles with the use of a recombinant DNA vector-enzymatic system, containing artificial poliepitopic proteins, for the delivery of new generation vaccines

DNA/RNA amplification technologies, such as the Polymerase Chain Reaction have revolutionized modern biology, medical diagnostics and forensic analyses, among others. A number of alternative nucleic acids amplification methods have been developed, tailored to specific applications. Here we present a refined version of a DNA fragment amplification technology, which enables the construction of ordered concatemers in a head-to-tail-orientation. A very high number of DNA segments, at least 500 copies, can be consecutively linked. Other key features include: (i) the application of a dedicated vector-enzymatic system, including selected subtype IIS restriction endonucleases, which has been designed to automatically generate long Open Reading Frames and (ii) an amplification-expression vector with a built-in strong transcription promoter along with optimal translation initiation signals, which allow for a high level of expression of the constructed artificial poliepitopic protein. This highly advanced technology makes it possible to obtain ordered polymers of monomeric, synthetic or natural, DNA far beyond the capabilities of current chemical synthesis methods. The constructed poliepitopic proteins are further used for construction of several types of nanoparticles, including inclusion bodies and bacteriophages, containing multiple genetic fusion with poliepitopic proteins.The technology offers significant advances in a number of scientific, industrial and medical applications, including new vaccines and tissue pro-regenerative methods. The technology is protected by an international patent application and is available for licensing. Acknowledgments: project was supported by National Center for Research and Development, Warsaw, Poland, grant no STRATEGMED1/235077/9/NCBR/2014 and POIG.01.04.00-22-140/12; Jagiellonian Center for Innovation, Krakow, Poland; SATUS VC, Warsaw, Poland and BioVentures Institute Ltd, Poznan, Poland

Bacteriophages of Thermophilic ‘Bacillus Group’ Bacteria—A Review

Bacteriophages of thermophiles are of increasing interest owing to their important roles in many biogeochemical, ecological processes and in biotechnology applications, including emerging bionanotechnology. However, due to lack of in-depth investigation, they are underrepresented in the known prokaryotic virosphere. Therefore, there is a considerable potential for the discovery of novel bacteriophage-host systems in various environments: marine and terrestrial hot springs, compost piles, soil, industrial hot waters, among others. This review aims at providing a reference compendium of thermophages characterized thus far, which infect the species of thermophilic ‘Bacillus group’ bacteria, mostly from Geobacillus sp. We have listed 56 thermophages, out of which the majority belong to the Siphoviridae family, others belong to the Myoviridae and Podoviridae families and, apparently, a few belong to the Sphaerolipoviridae, Tectiviridae or Corticoviridae families. All of their genomes are composed of dsDNA, either linear, circular or circularly permuted. Fourteen genomes have been sequenced; their sizes vary greatly from 35,055 bp to an exceptionally large genome of 160,590 bp. We have also included our unpublished data on TP-84, which infects Geobacillus stearothermophilus (G. stearothermophilus). Since the TP-84 genome sequence shows essentially no similarity to any previously characterized bacteriophage, we have defined TP-84 as a new species in the newly proposed genus Tp84virus within the Siphoviridae family. The information summary presented here may be helpful in comparative deciphering of the molecular basis of the thermophages’ biology, biotechnology and in analyzing the environmental aspects of the thermophages’ effect on the thermophile community

Analysis of Industrial <i>Bacillus</i> Species as Potential Probiotics for Dietary Supplements

So far, Bacillus species bacteria are being used as bacteria concentrates, supplementing cleaning preparations in order to reduce odor and expel pathogenic bacteria. Here, we discuss the potential of Bacillus species as ‘natural’ probiotics and evaluate their microbiological characteristics. An industrial microbiological concentrate CS-4 of mixed Bacillus species cultures was tested, which may be a promising bacteria source for food probiotic preparation for supplementary diet. In this study, antagonistic activities and probiotic potential of Bacillus species, derived from an industrial microbiological concentrate, were demonstrated. The cell free supernatants (CFS) from Bacillus licheniformis mostly inhibited the growth of foodborne pathogenic bacteria, such as Escherichia coli O157:H7 ATCC 35150, Salmonella Enteritidis KCCM 12021, and Staphylococcus aureus KCCM 11335, while some of Bacillus strains showed synergistic effect with foodborne pathogenic bacteria. Moreover, Bacillus strains identified by the MALDI TOF-MS method were found sensitive to chloramphenicol, kanamycin, and rifampicin. B. licheniformis and B. cereus displayed the least sensitivity to the other tested antibiotics, such as ampicillin, ampicillin and sulfbactam, streptomycin, and oxacillin and bacitracin. Furthermore, some of the bacterial species detected extended their growth range from the mesophilic to moderately thermophilic range, up to 54 °C. Thus, their potential sensitivity to thermophilic TP-84 bacteriophage, infecting thermophilic Bacilli, was tested for the purpose of isolation a new bacterial host for engineered bionanoparticles construction. We reason that the natural environmental microflora of non-pathogenic Bacillus species, especially B. licheniformis, can become a present probiotic remedy for many contemporary issues related to gastrointestinal tract health, especially for individuals under metabolic strain or for the increasingly growing group of lactose-intolerant people