DNA digestion and formation of DNA-network structures with Holliday junction-resolving enzyme Hjc_15-6 in conjunction with polymerase reactions

The recently identified novel Holliday junction-resolving enzyme, termed Hjc_15-6, activity investigation results imply DNA cleavage by Hjc_15-6 in a manner that potentially enhances the molecular self-assembly that may be exploited for creating DNA-networks and nanostructures. The study also demonstrates Pwo DNA polymerase acting in combination with Hjc_15-6 capability to produce large amounts of DNA that transforms into large DNA-network structures even without DNA template and primers. Furthermore, it is demonstrated that Hjc_15-6 prefers Holliday junction oligonucleotides as compared to Y-shaped oligonucleotides as well as efficiently cleaves typical branched products from isothermal DNA amplification of both linear and circular DNA templates amplified by phi29-like DNA polymerase. The assembly of large DNA network structures was observed in real time, by transmission electron microscopy, on negative stained grids that were freshly prepared, and also on the same grids after incubation for 4 days under constant cooling. Hence, Hjc_15-6 is a promising molecular tool for efficient production of various DNA origamis that may be implemented for a wide range of applications such as within medical biomaterials, catalytic materials, molecular devices and biosensors.

Crystal structure and initial characterization of a novel archaeal-like Holliday junction-resolving enzyme from Thermus thermophilus phage Tth15-6

This study describes the production, characterization and structure determination of a novel Holliday junction-resolving enzyme. The enzyme, termed Hjc_15-6, is encoded in the genome of phage Tth15-6, which infects Thermus thermophilus. Hjc_15-6 was heterologously produced in Escherichia coli and high yields of soluble and biologically active recombinant enzyme were obtained in both complex and defined media. Amino-acid sequence and structure comparison suggested that the enzyme belongs to a group of enzymes classified as archaeal Holliday junction-resolving enzymes, which are typically divalent metal ion-binding dimers that are able to cleave X-shaped dsDNA–Holliday junctions (Hjs). The crystal structure of Hjc_15-6 was determined to 2.5 Å resolution using the selenomethionine single-wavelength anomalous dispersion method. To our knowledge, this is the first crystal structure of an Hj-resolving enzyme originating from a bacteriophage that can be classified as an archaeal type of Hj-resolving enzyme. As such, it represents a new fold for Hj-resolving enzymes from phages. Characterization of the structure of Hjc_15-6 suggests that it may form a dimer, or even a homodimer of dimers, and activity studies show endonuclease activity towards Hjs. Furthermore, based on sequence analysis it is proposed that Hjc_15-6 has a three-part catalytic motif corresponding to E–SD–EVK, and this motif may be common among other Hj-resolving enzymes originating from thermophilic bacteriophages.

Going to extremes - a metagenomic journey into the dark matter of life

The Virus-X-Viral Metagenomics for Innovation Value-project was a scientific expedition to explore and exploit uncharted territory of genetic diversity in extreme natural environments such as geothermal hot springs and deep-sea ocean ecosystems. Specifically, the project was set to analyse and exploit viral metagenomes with the ultimate goal of developing new gene products with high innovation value for applications in biotechnology, pharmaceutical, medical, and the life science sectors. Viral gene pool analysis is also essential to obtain fundamental insight into ecosystem dynamics and to investigate how viruses influence the evolution of microbes and multicellular organisms. The Virus-X Consortium, established in 2016, included experts from eight European countries. The unique approach based on high throughput bioinformatics technologies combined with structural and functional studies resulted in the development of a biodiscovery pipeline of significant capacity and scale. The activities within the Virus-X consortium cover the entire range from bioprospecting and methods development in bioinformatics to protein production and characterisation, with the final goal of translating our results into new products for the bioeconomy. The significant impact the consortium made in all of these areas was possible due to the successful cooperation between expert teams that worked together to solve a complex scientific problem using state-of-the-art technologies as well as developing novel tools to explore the virosphere, widely considered as the last great frontier of life.

Biochemical Characterization and Validation of a Catalytic Site of a Highly Thermostable Ts2631 Endolysin from the Thermus scotoductus Phage vB_Tsc2631

Phage vB_Tsc2631 infects the extremophilic bacterium Thermus scotoductus MAT2631 and uses the Ts2631 endolysin for the release of its progeny. The Ts2631 endolysin is the first endolysin from thermophilic bacteriophage with an experimentally validated catalytic site. In silico analysis and computational modelling of the Ts2631 endolysin structure revealed a conserved Zn²⁺ binding site (His³⁰, Tyr⁵⁸, His¹³¹ and Cys¹³⁹) similar to Zn²⁺ binding site of eukaryotic peptidoglycan recognition proteins (PGRPs). We have shown that the Ts2631 endolysin lytic activity is dependent on divalent metal ions (Zn²⁺ and Ca²⁺). The Ts2631 endolysin substitution variants H30N, Y58F, H131N and C139S dramatically lost their antimicrobial activity, providing evidence for the role of the aforementioned residues in the lytic activity of the enzyme. The enzyme has proven to be not only thermoresistant, retaining 64.8% of its initial activity after 2 h at 95°C, but also highly thermodynamically stable (T_m = 99.82°C, ΔH_cal = 4.58 × 10⁴ cal mol^-1). Substitutions of histidine residues (H30N and H131N) and a cysteine residue (C139S) resulted in variants aggregating at temperatures ≥75°C, indicating a significant role of these residues in enzyme thermostability. The substrate spectrum of the Ts2631 endolysin included extremophiles of the genus Thermus but also Gram-negative mesophiles, such as Escherichia coli, Salmonella panama, Pseudomonas fluorescens and Serratia marcescens. The broad substrate spectrum and high thermostability of this endolysin makes it a good candidate for use as an antimicrobial agent to combat Gram-negative pathogens.

Highly thermostable RadA protein from the archaeon Pyrococcus woesei enhances specificity of simplex and multiplex PCR assays

The radA gene of the hyperthermophilic archaeon Pyrococcus woesei (Thermococcales) was cloned and overexpressed in Escherichia coli. The 1050-bp gene codes for a 349-amino-acid polypeptide with an M r of 38,397 which shows 100 % positional amino acid identity to Pyrococcus furiosus RadA and 27.1 % to the E. coli RecA protein. Recombinant RadA was overproduced in Escherichia coli as a His-tagged fusion protein and purified to electrophoretic homogeneity using a simple procedure consisting of ammonium sulfate precipitation and metal-affinity chromatography. In solution RadA exists as an undecamer (11-mer). The protein binds both to ssDNA and dsDNA. RadA has been found to be highly thermostable, it remains almost unaffected by a 4-h incubation at 94 °C. The addition of the RadA protein to either simplex or multiplex PCR assays, significantly improves the specificity of DNA amplification by eliminating non-specific products. Among applications tested the RadA protein proved to be useful in allelic discrimination assay of HADHA gene associated with long-chain 3-hydroxylacyl-CoA dehydrogenase deficiency that in infancy may lead to hypotonia, serious heart and liver problems and even sudden death.

192 EXPRESSION OF SELECTED ANTIOXIDANT ENZYMES IN BOVINE OVIDUCT EPITHELIAL CELL (BOEC) IN RESPONSE TO ELEVATED TEMPERATURES IN VITRO

Elevated temperatures have a negative impact on bovine reproduction. One of its effects is an increased concentration of reactive oxygen species (ROS) which may lead to female infertility. Oxidative stress impairs oocyte maturation, fertilization, and embryo development, and it also influences the reproductive tract. One of the defence mechanisms against the increase of ROS is the synthesis of antioxidants. Thus, the aim of this study was to analyse the expression of antioxidant enzymes (superoxide dismutase 1, SOD1; catalase, CAT; and glutathione peroxidase 1, GPX1) in bovine oviduct epithelial cells (BOEC) cultured with or without embryos at elevated temperatures. Ovaries and oviducts were collected from a slaughterhouse. BOECs were mechanically isolated from the oviducts. The oocytes were isolated from ovaries and then maturated and fertilized in vitro. BOEC, after formation of aggregates, were cultured (variant I) in 40-µL droplets of cultured medium (TCM199 25 mM HEPES medium supplemented with 10% FBS, 10 µg mL–1 gentamicin, and 50 µg mL–1 streptomycin) overlaid with mineral oil. Twenty aggregates per droplet were cultured at control (38.5°C) and elevated (41°C) temperatures for 168 h in 5% CO2 in air. Analogously, in variant II, BOEC aggregates were co-cultured with 15 bovine embryos per droplet. Subsequently, the SOD1, CAT, and GPX1 mRNA levels were analysed in BOEC by real-time RT–PCR (Light Cycler, Roche Diagnostics, Warsaw, Poland) and normalized to S18/H2A gene expression. Relative quantification was determined with LightCycler software version 3.5 (Roche Diagnostics) by the second derivative maximum method. Statistical analyses were performed by Portable Statgraphics 5.0 Centurion (Statpoint Technologies Inc., Warrenton, VA). Mean values of SOD1, CAT, and GPX1 expression in BOEC in RT-qPCR analysis were compared using Tukey's HSD test (a = 0.01). Elevated temperature leads to an up-regulation of SOD1 in BOEC cultured (38°C: 0.76 ± 0.12 a.u., n = 44; 41°C: 1.07 ± 0.21 a.u., n = 48) and co-cultured with bovine embryos (38°C: 0.71 ± 0.11 a.u., n = 36; 41°C: 1.04 ± 0.2 a.u., n = 36) and the difference was statistically significant (P < 0.01). The CAT gene expression in BOEC was constant in variant I (38°C: 0.56 ± 0.22 a.u., n = 56; 41°C: 0.58 ± 0.27 a.u., n = 56) and variant II (38°C: 0.48 ± 0.27 a.u., n = 32; 41°C: 0.59 ± 0.29 a.u., n = 24). Also, GPX1 gene expression in BOEC was constant in variant I (38°C: 0.66 ± 0.23 a.u., n = 60; 41°C: 0.61 ± 0.19 a.u., n = 56) and in variant II (38°C: 0.59 ± 0.19 a.u., n = 36; 41°C: 0.64 ± 0.22 a.u., n = 36). In conclusion, elevated temperature leads to an activation of the BOEC's defence mechanisms which are based on SOD1 expression, and which may protect cells against oxidative stress. Elevated temperature doesn't affect the cat and GPX1 expression in BOEC. The presence of embryos does not affect the expression of antioxidant enzymes in BOEC. Research was supported by COST DPN/DWM/MZ/5670/08/09.

167 THE EFFECT OF ELEVATED TEMPERATURE ON THE HEAT SHOCK PROTEIN 70 (HSP70) EXPRESSION IN BOVINE CUMULUS&ndash;OOCYTE COMPLEXES AFTER IN VITRO MATURATION

Elevated temperature during in vitro maturation negatively affects the oocyte's developmental competence, leading to disturbances in nuclear and cytoplasmic maturation. In previous studies, the role of cumulus granulosa cells (CGC) in cumulus-oocyte complexes' (COC) response to elevated temperature was underestimated. However, CGC play an essential role in folliculogenesis, supporting the oocyte's metabolism as well as meiotic progression. Thus, CGC may be engaged in COC response to heat shock. Heat shock protein 70 (HSP70) is the major protein engaged in cellular response to heat stress. The aim of this study was to determine the HSP70 expression in both CGC and oocytes in response to elevated temperature after COC in vitro maturation. COC were collected from bovine ovarian follicles (diameter 2–6 mm) from slaughtered cows and divided into two treatment groups: I (control) – COC were in vitro matured in control temperature (38.5°C); II (experimental) – COC were in vitro matured in elevated temperature (41°C). After in vitro maturation they were mechanically separated into CGC and oocyte. In vitro maturation was conducted in TCM199 25 mM HEPES medium supplemented with 10% FBS, 0.02 IU mL–1 NIH-pFSH, 1 μg mL–1 17β-oestradiol, 22 μg mL–1 Na-pyruvate and 10 μg mL–1 gentamicin, adjusted to pH 7.4 in 5% CO2. The HSP70 expression in CGC and oocytes was performed by real-time PCR and normalized to S18/H2A and S18 gene expression, respectively. In addition, the immunocytofluorescent analysis of HSP70 expression in CGC and oocyte's were performed. The HSP70 was stained using primary monoclonal mouse antibodies raised against bovine HSP70 and secondary antibody raised against mouse conjugated with Alexa 488. Nuclei were stained with Hoechst 33342. Slides were analysed under laser confocal microscope (FV-500, Olympus, Center Valley, PA, USA). The HSP70 expression in CGC was measured as total optical density of HSP70 and normalized to total optical density of nuclei. Statistical analyses were performed by Portable Statgraphics 5.0 Centurion. Mean values of HSP70 expression in CGC and oocytes in real-time PCR and immunofluorescent analysis in CGC were compared using Tukey's HSD test (α = 0.01). After in vitro maturation, the expression of HSP70 in CGC was higher (0.13 ± 0.052 a.u., n = 35) in experimental temperature compared to the control (0.058 ± 0.008 a.u., n = 35) (P < 0.01). In oocytes, HSP70 expression in experimental temperature (32.5 ± 5.2 a.u., n = 12) was similar to control (29.8 ± 5.6 a.u., n = 12). The immunofluorescent analysis confirmed data from real-time PCR analysis, indicating that the HSP70 expression in CGCs in experimental temperature was higher (0.46 ± 0.07 a.u., n = 10) compared to the control (0.12 ± 0.02 a.u., n = 10; P < 0.01). After COC in vitro maturation in stress conditions, the HSP70 expression was up-regulated in CGC, but not in oocytes. That may indicate that CGCs play the major role in COC response to elevated temperature; however, the analysis of other heat shock proteins expression in CGC and oocytes need to be conducted. Research was supported by 505-10-023300-K00169-99.

173 THE IMPACT OF ELEVATED TEMPERATURE ON HSP70 EXPRESSION IN CATTLE MURAL GRANULOSA CELLS

Elevated temperature has an adverse impact on cattle fertility, causing disorders in ovarian functions and follicle development. Heat shock caused by elevated temperature leads to disruption in the cytoskeleton structure and the nuclear maturation of oocytes. Furthermore, it has an impact on mural granulosa cells (MGC), which are responsible for maintaining an appropriate microenvironment for oocyte development and signal transmission through the ovarian follicle. Heat-shock protein 70 is considered as a fundamental marker of cellular defence mechanisms related to heat shock. It protects other proteins from denaturation by forming complexes and stabilisation of their structure. HSP70 has also an ability to repair damaged proteins and allows them to return to their native structure. Furthermore, members of the HSP70 subfamily participate in the folding of newly synthesised proteins and their transport to different cell compartments. The aim of this study was to determine the impact of elevated temperature on HSP70 expression in mural granulosa cells. MGCs were obtained postmortem from mural layers of cattle ovarian follicles with diameters greater than 15 mm and randomly assigned to one of 5 variants: I (control) – MGCs after isolation; II – MGCs cultured in medium with LH at 38.5°C; III – MGCs cultured in medium with LH at elevated temperature, 41°C; IV – MGCs cultured in medium without LH at 38.5°C; and V – MGCs cultured in medium without LH at elevated temperature, 41°C. HSP70 expression was determined using real-time PCR method, and was normalised to s18/h2a expression. Statistical analysis was made in Statgraphics (Statpoint Technologies Inc., Warrenton, VA, USA; P = 0.01) using one-way ANOVA to compare expression of hsp70 between experimental variants and multifactor ANOVA to determine the influence of temperature and LH stimulation on hsp70 expression. Mean values of hsp70 expression in real-time PCR were compared using Tukey's test (a = 0.05). The significant increase of hsp70 expression was observed in MGCs cultured at 41°C (groups III and V) in comparison to MGCs cultured at 38.5°C (groups II and IV) and the control group. Simultaneously, there is no significant impact of LH stimulation on hsp70 expression. In conclusion, mural granulosa cells are susceptible to elevated temperature, which induces activation of cellular defence mechanisms performed by increased hsp70 expression. This may lead to disorders in the function of MGCs followed by changes in follicular fluid composition and signal transmission through the follicle. Research was supported by 505-10-023300-L00171-99.

258 THE PRELIMINARY RESULTS OF IN VITRO PRODUCTION OF THE WISENT HYBRID EMBRYOS

Wisent (Bison bonasus), also called the European bison, is listed as vulnerable on the International Union for the Conservation of Nature Red List of Threatened Species. In Poland, a program for protection in situ and ex situ is being implemented. One new approach is the use of the in vitro embryo production (IVP) procedures to obtain wisent offspring. In contrast to previous successes with cattle IVP, use of IVP with wisent is limited by the small size of the population (only ~5000 individuals in more than 200 herds in Europe) and seasonal reproduction. The aim of this preliminary study was to obtain hybrid embryos (Bison bonasus × Bos taurus) in vitro. Ovaries were isolated from wisent females outside the reproductive season and eliminated from breeding for reasons other than infertility. Cumulus-oocytes complexes (COC) were isolated from all follicles above 2 mm in diameter. All COC were matured in TCM 199 supplemented with 10% fetal bovine serum, 0.02 IU mL–1 of porcine FSH, 17 β-oestradiol, 0.2 mM Na pyruvate, and antibiotics. The COC were cultured for 24 h at 38.5°C and 5% CO2 in humidified air. The matured COC (Bison bonasus) were fertilized in vitro with sperm from Jersey bulls (Bos taurus) in TALP supplemented with 6 mg mL–1 of fatty acid free BSA (BSA FAF), 0.2 mM Na pyruvate, 20 µM penicillamine,10 µM hypotaurine, 1 µM epinephrine, 2 µg mL–1 heparin, and antibiotics. Spermatozoa were used at a final concentration of 1 × 105 per oocyte and were co-cultured for 18 h at 38.5°C and 5% CO2 in humidified air. The hybrid zygotes were cultured in KSOM supplemented with 5 µg mL–1 of MEM Nonessential Amino Acid Solution (100×), 3 mg mL–1 of BSA FAF, and antibiotic for 192 h at 38.5°C and 5% CO2 in humidified air. The medium was partly replaced by fresh medium after 48 and 144 h of culture. Development was evaluated every day. From 25 COC isolated from wisent ovaries, only 18 COC were qualified for in vitro maturation (60%). Of these, 15 COC (83.3%) matured. The percentage of hybrid embryos that cleaved was 80% after 48 h of culture, and the percentage of embryos that developed up to the 8-cell stage was 33% after 96 h of culture. The morula/blastocyst rate was 26.6% after 192 h of culture, as represented by 1 early blastocyst, 2 compact morulae, and 1 morula. The use of the cattle IVP procedure allowed to receive hybrid embryos (Bison bonasus × Bos taurus), but they developed slower than cattle embryos under the same conditions, based on our previous studies. This research will be continued and may make a contribution to the protection of this threatened species.

Discovery and characterization of RecA protein of thermophilic bacterium Thermus thermophilus MAT72 phage Tt72 that increases specificity of a PCR-based DNA amplification

The recA gene of newly discovered Thermus thermophilus MAT72 phage Tt72 (Myoviridae) was cloned and overexpressed in Escherichia coli. The 1020-bp gene codes for a 339-amino-acid polypeptide with an Mr of 38,155 which shows 38.7% positional identity to the E. coli RecA protein. When expressed in E. coli, the Tt72 recA gene did not confer the ability to complement the ultraviolet light (254nm) sensitivity of an E. coli recA mutant. Tt72 RecA protein has been purified with good yield to catalytic and electrophoretic homogeneity using a three-step chromatography procedure. Biochemical characterization indicated that the protein can pair and promote ATP-dependent strand exchange reaction resulting in formation of a heteroduplex DNA at 60°C under conditions otherwise optimal for E. coli RecA. When the Tt72 RecA protein was included in a standard PCR-based DNA amplification reaction, the specificity of the PCR assays was significantly improved by eliminating non-specific products.

Reclassification of Thermoanaerobium acetigenum as Caldicellulosiruptor acetigenus comb. nov. and emendation of the genus description

Although the type species of the genus Thermoanaerobium, Thermoanaerobium brockii, was transferred to Thermoanaerobacter, Thermoanaerobium acetigenum was not transferred. Therefore, Thermoanaerobium acetigenum should be reclassified. Based on 16S rRNA gene sequence analysis and re-examination of physiological properties of the type strain, X6B(T) (=DSM 7040(T) = ATCC BAA-1149(T)), we propose that Thermoanaerobium acetigenum should be reclassified as Caldicellulosiruptor acetigenus comb. nov. Strain X6B(T) contains two separate 16S rRNA genes bracketing another species in the phylogenetic 16S rRNA gene-based tree.

Anaerobic digestion of manure and mixture of manure with lipids: biogas reactor performance and microbial community analysis

Anaerobic digestion of cattle manure and a mixture of cattle manure with glycerol trioleate (GTO) was studied in lab-scale, continuously stirred tank reactors (CSTR) operated at 37 degrees C. The reactor codigesting manure and lipids exhibited a significantly higher specific methane yield and a higher removal of VS than the reactor treating manure. Microbial population analysis done by cultivation--most probable number (MPN) test and specific methanogenic activity (SMA) measurement, revealed higher MPN and increased SMA of methanogenic populations of biomass from the reactor codigesting manure and lipids. Spatial microbial distribution and activity was studied in digested materials fractionated into size of particles > 200 microm, 50-200 microm and 0.45-50 microm. With manure, the main pool of methanogenic activity from propionate, butyrate and hydrogen was associated with the particles > 200 microm, while the activity of acetotrophic methanogens was uniformly distributed in all fractions. When digesting manure and lipids, an enhanced methanogenesis was detected both for particles > 200 microm and the 50-200 microm fraction. The molecular methods--temperature gradient gel electrophoresis (TGGE), cloning library and sequencing of 16S rDNA--showed presence of a restricted number of archaeal species in both reactors. The vast majority of clones was phylogenetically most closely related to Methanosarcina siciliae.

Function of insulin-like growth factor (IGF-I) and its binding protein (IGFBP-1) in pathological proliferation of endometrium

The purpose of this project was the investigation of insulin, IGF-I and IGFBP-1 concentrations in the serum of patients with pathological changes in endometrium. IGF-I and its binding protein (IGFBP-1) stimulate cell growth and differentiation of the normal and neoplastic endometrium. The mean values of IGF-I concentrations in the group of patients with atypical hyperplasia and endometrial carcinoma were significantly higher than in the control group with normal endometrium. Significantly higher IGFBP-1 concentrations were found in the serum of patients with the atypical hyperplasia of endometrium and endometrial carcinoma. The correlation between insulin concentration and changes in endometrium in the examined groups was not found.

Fluorescent protein vector for directional selection of PCR clones

Green fluorescent protein (GFP) has become a convenient and versatile tool as a reporter protein in many aspects of science. Here, we show that the enhanced yellow fluorescent protein (EYFP) variant may be used advantageously as a reporter system for directional cloning of blunt-ended PCR products. We have constructed a pUC18-derived plasmid containing a reporter gene coding EYFP cloned into the BamHI/HindIII sites. The blunt-ended PCR product is cloned into the SmaI site of that plasmid. A reverse PCR primer must be designed with extra bases on the 5' end that are required to introduce a ribosome binding site (rbs) for EYFP expression. The reporter gene coding EYFP is not expressed unless an rbs is introduced in the proper orientation at the 3' end of the cloned PCR insert. The results of this cloning procedure may be analyzed by simple visual inspection using a transilluminator. In most cases, successful directional cloning results in white fluorescent colonies. The proposed procedure is a convenient method that can reduce the time- and labor-intensive analysis of the clones obtained during blunt-ended PCR product cloning.

[Laparotomy performed in pregnant women due to non-obstetrical causes]

OBJECTIVE

The clinical characteristics of laparotomy during pregnancy were investigated.

MATERIALS AND METHODS

A series of 24 cases of laparotomy during pregnancy was investigated with respect to clinicopathologic features and outcome.

RESULTS

Among 23 cases there were 20 ovarian tumors, 2 acute appendicitis and 2 uterine fibroid. Gestational ages at the time of surgery ranged from 16 to 24 weeks of patients with ovarian tumors and from 30 to 32 weeks in others. No intraoperative or postoperative maternal or fetal complications occurred. One patient had a stage III ovarian carcinoma and went to total hysterectomy, and other patient had a stage IA ovarian carcinoma.

CONCLUSIONS

Appendectomy can be performed without additional risk to the fetus for those who require surgical intervention during pregnancy. Ovarian surgery in pregnancy for persistent masses is important to obtain a final histologic diagnosis.

Protection of cattle against bovine leukemia virus (BLV) infection could be attained by DNA vaccination

The bovine leukemia virus (BLV) envelope gene encoding extracellular glycoprotein gp51 and transmembrane glycoprotein gp30 was cloned into a vehicle expression vector under the human cytomegalovirus (CMV) intermediate early promoter. The intramuscular injection of this plasmid vector generated a cellular immune response. Seven out of ten cows vaccinated with the DNA construct resisted a drastic challenge (500 BLV-infected lymphocytes as an infectious dose).

Protection of cattle against bovine leukemia virus (BLV) infection could be attained by DNA vaccination

The bovine leukemia virus (BLV) envelope gene encoding extracellular glycoprotein gp51 and transmembrane glycoprotein gp30 was cloned into a vehicle expression vector under the human cytomegalovirus (CMV) intermediate early promoter. The intramuscular injection of this plasmid vector generated a cellular immune response. Seven out of ten cows vaccinated with the DNA construct resisted a drastic challenge (500 BLV-infected lymphocytes as an infectious dose).

Cloning, overexpression, and purification of the recombinant His-tagged SSB protein of Escherichia coli and use in polymerase chain reaction amplification

Polymerase chain reaction (PCR)-derived DNA fragment containing the complete structural gene for SSB protein of the Escherichia coli was cloned into an expression vector. The clones expressing His-tagged SSB protein were selected. The cloned DNA fragments were verified to be authentic by sequencing several clones. The recombinant SSB protein (His-tagged SSB) contained a polyhistidine tag at the N-terminus (38 additional amino acids) that allowed single-step isolation by Ni2+ affinity chromatography. We found that recombinant plasmids are unstable and give a low level of expression in E. coli BL21(DE3) strain. However, the plasmids were stable in E. coli BL21(DE3) containing the pLysS plasmid, which suppresses expression prior to induction, and His-tagged proteins were highly expressed upon IPTG addition. The SSB protein was purified by metal-affinity chromatography on Ni2+-TED-Sepharose columns. The enzyme was characterized by fluorescence titration experiments for single-stranded DNA binding activity. We have applied the use of His-tagged SSB protein to increase amplification efficiency with a number of diverse templates. The use of SSB protein may prove to be generally applicable in improving PCR efficiency.

Recombinant His-tagged DNA polymerase. I. Cloning, purification and partial characterization of Thermus thermophilus recombinant DNA polymerase

The Tth DNA polymerase gene from the thermophilic Thermus thermophilus (strain HB8) was amplified, cloned and expressed in Escherichia coli. The recombinant DNA polymerase containing a polyhistidine tag at the N-terminus was isolated in a single step by Ni2+ affinity chromatography. The purified recombinant enzyme, showing high polymerase activity contained 43 additional amino-acid residues (including a cluster of six histidine residues inserted for purification of the recombinant protein by metal-affinity chromatography) at N-terminus. The applied overexpression system was very efficient giving 700,000 u of DNA polymerase activity from 1 liter of induced culture. The enzyme was characterized and displayed high DNA polymerase and reverse transcriptase activities and high thermostability as compared to the native Tth DNA polymerase.

Recombinant His-tagged DNA polymerase. II. Cloning and purification of Thermus aquaticus recombinant DNA polymerase (Stoffel fragment)

The Stoffel DNA fragment, shortened by 12 bp from 5' end, coding for Stoffel DNA polymerase (missing 4 amino acids at N-terminus of Stoffel amino-acids sequence) from the thermophilic Thermus aquaticus (strain YT-1) was amplified, cloned and expressed in Escherichia coli. The recombinant Stoffel fragment contained a polyhistidine tag at the N-terminus (21 additional amino acids) that allowed its single-step isolation by Ni2+ affinity chromatography. The enzyme was characterized and displayed high DNA polymerase activity and thermostability evidently higher than the native Taq DNA polymerase.

Cloning and nucleotide sequence of the thermostable beta-galactosidase gene from Pyrococcus woesei in Escherichia coli and some properties of the isolated enzyme

Pyrococcus woesei (DSM 3773) beta-galactosidase gene amplified by polymerase chain reaction was cloned into KpnI and HindIII binding sites of pET-30LIC expression plasmid. The obtained pGal2 (6785 bp) transcription vector was then transferred to Escherichia coli B121 (DE3) cells. High identity (99.9%) of DNA sequences suggests that beta-galactosidases from P. woesei and Pyrococcus furiosus are closely related. This enzyme from E. coli transformant is a unique thermostable protein in the cells and can be successfully separated by thermal precipitation of other bacterial proteins at 85 degrees C. The crude beta-galactosidase remaining in the solution comprises about 21% of the total amount of proteins extracted from E. coli cells and has maximal activity at pH 5.4 and temperature of 93 degrees C. Isolated enzyme is active at temperatures up to 110 degrees C and the activity loss after 4 h of incubation at 85 and 93 degrees C did not exceed 11 and 15% of the initial value respectively.

Cloning and expression in Escherichia coli of the recombinant his-tagged DNA polymerases from Pyrococcus furiosus and Pyrococcus woesei

Complete PCR-derived DNA fragments containing the structural genes for DNA polymerases of the archaeons Pyrococcus furiosus and Pyrococcus woesei were cloned into an expression vector. The clones expressing thermostable His-tagged DNA polymerases were selected. The cloned fragments were sequenced. The DNA sequences were verified to be authentic by sequencing several clones. The nucleotide (nt) sequence revealed that DNA polymerase of P. woesei (Pwo DNA polymerase) consists of 775 amino acids and has a molecular weight of 90,566. It shows 100% nucleotide identity to the nucleotide sequence of DNA polymerase from P. furiosus (Pfu DNA polymerase). The results confirm that nucleotide sequences of both archaeons (P. furiosus and P. woesei) are highly similar. The recombinant DNA polymerases (His-tagged Pfu and His-tagged Pwo) contained a polyhistidine tag at the N-terminus (43 additional amino acids) that allowed single-step isolation by Ni-affinity chromatography. We found that recombinant plasmids are toxic or unstable in the expressing strain BL21(DE3), even in the absence of the inducing agent, IPTG. However, the plasmids were stable in BL21(DE3) containing the pLysS plasmid, which suppresses expression prior to induction, and His-tagged proteins were expressed upon IPTG addition. The proteins were purified by heat treatment (to denature E. coli proteins), followed by metal-affinity chromatography on Ni2+-Sepharose columns. The enzymes were characterized and displayed high DNA polymerase activity and thermostability. This bacterial expression system appears to be the method of choice for production of Pfu or Pwo DNA polymerases.

Recombinant His-tagged DNA polymerase. I. Cloning, purification and partial characterization of Thermus thermophilus recombinant DNA polymerase

The Tth DNA polymerase gene from the thermophilic Thermus thermophilus (strain HB8) was amplified, cloned and expressed in Escherichia coli. The recombinant DNA polymerase containing a polyhistidine tag at the N-terminus was isolated in a single step by Ni2+ affinity chromatography. The purified recombinant enzyme, showing high polymerase activity contained 43 additional amino-acid residues (including a cluster of six histidine residues inserted for purification of the recombinant protein by metal-affinity chromatography) at N-terminus. The applied overexpression system was very efficient giving 700,000 u of DNA polymerase activity from 1 liter of induced culture. The enzyme was characterized and displayed high DNA polymerase and reverse transcriptase activities and high thermostability as compared to the native Tth DNA polymerase.

Recombinant His-tagged DNA polymerase. II. Cloning and purification of Thermus aquaticus recombinant DNA polymerase (Stoffel fragment)

The Stoffel DNA fragment, shortened by 12 bp from 5' end, coding for Stoffel DNA polymerase (missing 4 amino acids at N-terminus of Stoffel amino-acids sequence) from the thermophilic Thermus aquaticus (strain YT-1) was amplified, cloned and expressed in Escherichia coli. The recombinant Stoffel fragment contained a polyhistidine tag at the N-terminus (21 additional amino acids) that allowed its single-step isolation by Ni2+ affinity chromatography. The enzyme was characterized and displayed high DNA polymerase activity and thermostability evidently higher than the native Taq DNA polymerase.

[Community self-help houses as a form of community social support]

Two forms of community-based social support were introduced by the Polish Mental Health Act--community specialist social help services and community self-help houses--for seriously mentally ill and severely mentally retarded persons. According to the art. 8 community social support should be organized by social help agencies in consultation with psychiatric facilities. Data obtained from the Ministry of Labour and Social Policy indicated that from 21th of January 1995 (when the Mental Health Act was put in force) until 30th of June 1997 social help agencies and non-governmental organizations sponsored by social help agencies have set up 134 community self-help houses with 4103 places. In the middle of last year nearly 3500 persons were using these houses. Most of the houses were located in the following districts: Gdańsk (20), Gorzów (16), Płock (12), Warszawa (8 for 164 persons). Vast majority of them served as day rehabilitation houses, while only a few provided sheltered housing as well. Tentative evaluation of functioning of these houses shows that: operational definition of community self-help house given in the target network of nursing homes and community self-help houses should be modified to include statutory purposes of community social support provided in art.8, selection of the persons using community self-help houses should follow the legal requirement of the Mental Health Act (art. 8), separated rehabilitation programs for mentally ill (psychotic) and mentally retarded persons need to be provided, participation of psychiatric facilities in the organization of the community self-help houses should be increased, functioning of the community self-help houses ought to be supervised by specialists, staff of the community self-help houses need to be systematically trained.

[Specialist community social services as a form of community social support]

Art. 9 of the Polish Mental Health Act provides two forms of community-based social support--specialist social help services and community self-help houses for persons who, due a to serious mental illness or severe mental retardation, face considerable difficulties in their daily life, especially with respect to interpersonal relations, employment and welfare matters. The first form could only be implemented after coming into force of the suitable regulation of the Ministry of Labour and Social Policy of December 18, 1996 (Dz. U. z 1997 r., nr. 2, poz. 12). Hence, it may be understood that information on these services is exceptionally scarce. The author presents: a draft of legal evolution of the specialist services, from the vague idea of "community care" provided by psychiatric care facilities to the present regulation of community specialist social help services run by social help agencies in consultation with psychiatric facilities, main guidelines for staff to be observed in performing community specialist social help services (training in maintenance and development of basic skills necessary to independent living and others), the first promising experiences of a team rendering community specialist social help services in one of the communes in Warsaw.

[Decentralization of psychiatric health service]

The article discusses two stages of de-centralization of psychiatric hospitals: the first consists in further division into sub-districts, the second one includes successive establishment of psychiatric wards in general hospitals. With the growth of their number these wards are to take over more and more general psychiatric tasks from the specialized psychiatric hospitals. These wards will not substitute psychiatric hospitals completely. The hospitals, though decreasing in size and number, will be a necessary element of the de-centralized and versatile psychiatric care for a long time to come.

[Assessment of threatening behaviors in patients admitted to mental hospital]

Imminent threat presented by patients admitted to mental hospital was studied. The research data came from a questionnaire filled out by psychiatrists on duty at the time of admission. The study was carried out during 3 months in seven mental hospitals. It concerns only 1001 patients assessed by psychiatrists as imminently threatening. These assessments were compared with Lessard's criteria of dangerousness. Two types of assessments were made; type A--consistent with Lessard and type B not-consistent. Results obtained indicate that every third assessment belonged to type B i.e. could be seen as imminently threatening. Our findings show that psychiatrists taking part in the study were inclined to unduly broad or unduly discretional assessment of imminent threat.

Treatment, care, and rehabilitation of the chronic mentally ill in Poland

In Poland primary health settings provide about 71 percent of mental health services, particularly to patients with less serious illnesses, while psychiatry provides specialized mental health care for the chronic mentally ill, the mentally retarded, and patients with alcohol or drug dependence. Poland has a large number of outpatient clinics and an extensive network of sheltered workshops. Most inpatient psychiatric beds are located in mental hospitals; few general hospitals have psychiatric units. Deinstitutionalization has been less extensive in Poland than in many other countries; only about 10 percent of the chronic patients treated in mental hospitals were deinstitutionalized between 1970 and 1981. During that period the proportion of patients hospitalized for a year or more decreased, the number of chronic patients treated in nursing homes increased, and the pattern of hospitalization shifted toward multiple readmissions.

[Treatment of acute leukemias in adults. IV. Treatment results on 375 patients at 9 hematology centers]

On the basis of standardized protocols of the therapeutic results of acute non-lymphoblastic leukaemias in adults sent to the Institute of Haematology in Warsaw from 8 haematological centres in Poland it was demonstrated that complete remission occurred in 34.4% of patients (129 out of 375 cases). The mean survival time of the patients treated intensively according to programmes I, II, III and IV 8.6 months, those of patients with complete remission - 13.5 months, patients without complete remission - 3.7 months. The most frequent cause of death (82.5%) were infections and/or haemarrhagic diathesis.

The adductor transfer in the high-risk hip in myelodysplasia: a preliminary report

Hip instability occurs in meningomyelocele patients with lumbar level paralysis because of muscle imbalance. Transferring the hip adductor origins to the ischium can be used as the primary procedure to restore muscle balance and prevent hip instability in myelodysplasia patients if performed by the age of one year. Twelve lumbar meningomyelocele patients underwent bilateral adductor transfers. Secondary procedures, such as iliopsoas release or transfer or varus derotation osteotomy, were done in 14 hips. Ten hips needed no further surgery. Twenty of 24 hips were clinically and roentgenographically stable and showed roentgenographic evidence of improving hip development. Instability was associated with scoliosis, congenital dislocation, and age greater than one year at the time of the transfer.