Complete sequencing of potato virus X new strain genome and construction of viral vector for production of target proteins in plants

The complete nucleotide sequence of the genome of a new potato virus X (PVX) strain Tula isolated by us has been determined. Based on comparison of the PVX Tula nucleotide sequence with the sequences of 12 other PVX strains, this strain was assigned to the European cluster of PVX strains. Phylogenetic analysis revealed the same phylogeny for both full genome sequences and nucleotide sequences of polymerase and coat protein genes, suggesting that the PVX evolution did not involve recombination between different strains. The full-size cDNA copy of the PVX Tula genome was cloned and the accumulation of the viral coat protein in infected Nicotiana benthamiana was shown to be about twofold higher than for the PVX strain UK3. Based on the PVX Tula genome, a new vector which contained the target gene instead of the removed triple transport gene block and the coat protein gene has been constructed for expression of target proteins in plants. The productivity of the new vector was about 1.5-2-fold higher than the productivity of the vector of the same structure based on the standard PVX strain genome. The new viral vector can be used for superproduction of recombinant proteins in plants.

[Comparative study of structural stabylity of potato virus X coat protein molecules in solution and in the virus particles]

With help of several optical methods and differential scanning calorimetry we studied the structure and stability of molecules of coat protein (CP) of filamentous of potato virus X (PVX) in free state and in the virions. According to the results of all these methods, at room temperature (25 degrees C) free PVX CP subunits possess some fixed tertiary structure but this structure is highly unstable and is completely disrupted at temperatures as low as 35 degrees C. The free PVX CP tertiary structure was also disrupted by very low sodium dodecylsulfate and cetyltrimetylammonium bromide concentrations: 3 to 5 moleculs of the surfactants per the CP molecule were sufficient to induce its total disruption. At the same time, these treatments did not result in any changes in the PVX CP secondary structure. Incorporation of the CP subunits into the PVX virions resulted in a strong increase in their stability to effects of increased temperatures and surfactants. This combination of highly labile tertiary structure and rather stable secondary structure of free PVX CP subunits may represent a structural basis for recently observed capacity of the PVX CP moleculs to assume two different functional states in the virion.

[Experimental comparative evaluation of the functional capacities of ectopically grown fetal organs]

The interest for fetal organ, tissue, and cell implantation as therapeutic means in the treatment of some diseases is presently increasing. Hence, the aim of the present investigation was the comparative evaluation of the functional potential of ectopically grown fetal organs of different (ecto-, meso- and endodermic) origins. Unified operative model was the fetal organ fragment implantation into an ear subcutaneous pouch (without restoration of vascular and nervous links of the implant with the recipient organism). The implant isolation in vitro varied from 15 to 50 min. As control, intact animals and animals with streptozotocin diabetes and hepatic lesions due to the main bile duct ligature, were used. The implanted and ectopically grown fetal organs, though of different origins, developed functional activity. The best adult-like function was obtained in intestinal, gastric and cardiac implants, i.e. in organs with a cavity and a well developed self-regulation system. Poorer results were obtained in great digestive glandular implants--pancreas and liver. In the best cases when the implant function was very closed to the adult organ, a difference nevertheless was observed. The model of ectopic implantation of fetal organs may be useful for study of the organ and tissue function ontogenesis (up to the moment of natural ageing involution), for the evaluation of different isolated factor influence on organ and tissue physiology and pathology. Although being optimistic in respect to clinical application of fetal organ and cell implantation, this study does not prevent us from being cautions.

[Thrombectomy as a method of surgical treatment of thrombosis of a mechanical prosthesis of the heart valve (a description of three cases)]

The article presents three clinical observations of successful thrombectomies in patients with thromboses of modern bicuspid prostheses of the heart (MEDINZH-2, Carbo Medics) which was 21.4% of all operations (14) for acute thrombosis of the artificial heart valve. It should be taken into consideration that such kind of operation is possible when there are easily removed small loose thrombus, good fixation of the prosthesis and a complete endothelization of the cuff.

[Early results of surgical treatment of infective endocarditis]

Operations were performed on 183 patients with infective endocarditis and injury of the valve apparatus of the heart. Duration of the disease was from 5 weeks to 9 years. Insufficiency of circulation of the III-IV functional class was noted in 92% of the patients. High activity of the infective process observed in 30% of the patients by the moment of operation did not influence the results of surgical treatment. Postoperative lethality was 7.6%.

[On the etiology of aortal insufficiency]

The authors describe the results of valvulometry, traditional histological and cytological investigations of dissected valves of 1084 patients and an analysis of causes of aortal insufficiency as compared to the literature data for the last 80 years. The main causes of heart valve diseases are considered to be mesenchymal dysplasia and infective endocarditis.

[Immediate results of using the radial artery in direct revascularization of the myocardium]

The authors discuss results of more than 300 operations of the aorto-coronary bypass using the radial artery as a shunt. An analysis of the initial state of the patients, the intraoperative, early postoperative and intrahospital periods was made. Special attention was given to specific features of the isolating and using the radial artery grafts. Specific complications resulting from the application of them were analyzed and recommendations are given for prophylactics of such complications. The experiences with using the radial arteries allow to recommend it in revascularization of the myocardium. It is one of the ways of improving immediate and long-term results of operations on patients with ischemic heart disease.

Translational activation of encapsidated potato virus X RNA by coat protein phosphorylation

Previously we showed that encapsidated potato virus X (PVX) RNA is nontranslatable in vitro, but can be converted into a translatable form after binding to PVX particles of PVX-coded movement protein, the product of the first gene of triple gene block (TGBp1). Here we report that a similar effect occurs via in situ phosphorylation of the PVX coat protein (CP) by Ser/Thr protein kinase (PK) C, the mixture of casein kinases I and II or by cytoplasmic PK(s) from Nicotiana glutinosa leaves. Immunochemical analyses indicated that phosphorylation induced conformational changes in PVX CP. The N-terminal region of the PVX CP, rich in Ser and Thr residues, is exposed at the virion surface and can be removed by treatment with trypsin. We showed that (i) trypsin treatment removed the bulk of (32)P-radioactivity from in situ phosphorylated PVX CP, (ii) PVX containing N-terminally truncated CP (PVX-Ptd) failed to be translationally activated by phosphorylation, and (iii) the specific infectivity of PVX-Ptd was reduced. However, the PVX-Ptd RNA remained intact and PVX-Ptd could be translationally activated by the PVX MP TGBp1. We hypothesize that phosphorylation of the parental PVX by cytoplasmic PK(s) in vivo renders PVX RNA translatable in primary inoculated cells, whereas translational activation of the progeny virions destined for plasmodesmata trafficking is triggered by TGBp1.

[A method of isolation and preparation of the radial artery for direct revascularization of the myocardium]

The authors describe a technique of the isolation, preparation and use of the radial artery for the aortocoronary shunting for ischemic heart disease. The method is anatomically valid and approbated in 300 operations on the open heart. Safety and efficiency of using the radial artery is due to its not traumatic isolation, original preparing for shunting and medicamental prevention of its spasm.

[Rare causes of the dysfunction of mechanical bicuspid heart valves]

The authors share the observations from their cardiosurgical practice showing that one of the causes of sudden death or of rapid worsening of the state of patients with implanted bicuspid artificial valves might be their dysfunction resulting both from breakage of the hinged mechanisms of the valve with its dislocation and migration and from the disturbed mobility of the valve cusp due to a thrombus formed in the atrium. The observations show that the "ideal" construction of the valve is to be created.

Properties of the coat protein of a new tobacco mosaic virus coat protein ts-mutant

Amino acid substitutions in a majority of tobacco mosaic virus (TMV) coat protein (CP) ts-mutants have previously been mapped to the same region of the CP molecule tertiary structure, located at a distance of about 70 A from TMV virion axis. In the present work some properties of a new TMV CP ts-mutant ts21-66 (two substitutions I21=>T and D66=>G, both in the 70-A region) were studied. Thermal inactivation characteristics, sedimentation properties, circular dichroism spectra, and modification by a lysine-specific reagent, trinitrobenzensulfonic acid, of ts21-66 CP were compared with those of wild-type (U1) TMV CP. It is concluded that the 70-A region represents the most labile portion of the TMV CP molecule. Partial disordering of this region in the mutant CP at permissive temperatures leads to loss of the capacity to form two-layer aggregates of the cylindrical type, while further disordering induced by mild heating results also in the loss of the ability to form ordered helical aggregates.

[The transplantation to adult animals of the pancreas from fetuses]

The possibility of using the syngeneic and allogeneic foetal pancreas implantation was shown for therapy of diabetes mellitus. Cases of the implantation with no immunosuppression were studied in 57 patients.

Complete nucleotide sequence and genome organization of a tobamovirus infecting cruciferae plants

Genomic RNA sequence of a tobamovirus infecting cruciferae plants (cr-TMV) was determined. The RNA is composed of 6312 nucleotides and contains four ORFs encoding the proteins of 122K (ORF1), 178K (ORF2), 29K (ORF3) and 18K (capsid protein, ORF4). ORF4 overlaps ORF3 by 74 nucleotides and the overlapping region can be folded into a stable hairpin structure. The 3'-terminal region of the cr-TMV RNA preceding the tRNA-like structure was shown to form six potentially stable pseudoknots.

[The transplantation to adult animals of fetal small intestine]

Use of the ectopic growth (culture) of foetal small intestine in vivo as a model for study of normal and pathological development of an organ or its different structures was shown to be possible. Complete structural and functional development of foetal small intestine was reached under certain conditions of its implantation.

[Study of the process of thermal aggregation of several representative tobamovirus coat proteins]

The role of the specific region of the tobacco mosaic virus (TMV) coat protein (CP) molecule (called "70A degree-region") in the regulation of ordered and unordered CP aggregation was investigated. CPs of the wild type TMV (strain U1), of temperature sensitive mutant with two amino acid substitutions in the "70A degree-region", and of cucumber virus 3 which is related to TMV but has a completely different structure in the "70A degree-region" were used. With the help of two different tests the processes of temperature-induced unordered aggregation of these three CPs were compared in solutions of different ionic strength and pH. On the basis of the data obtained it was concluded that the "70A-region" represents the most thermolabile region in the TMV CP molecule and that local thermal denaturation of this region results in unordered aggregation, when solution conditions (ionic strength and pH) favor formation of relatively large ordered aggregates (20S-"disks" or helical repolymerized protein).

Genome characterization and taxonomy of Plantago asiatica mosaic potexvirus

The complete nucleotide sequence of Plantago asiatica mosaic virus (P1AMV) genomic RNA has been determined. The 6128 nucleotide sequence contains five open reading frames (ORFs) coding for proteins of M(r) 156K (ORF1), 25K (ORF2), 12K (ORF3), 13K (ORF4) and 22K (ORF5). The sequences of these P1AMV proteins exhibit strong homology to the proteins of the other potexviruses. Phylogenetic trees based on the multiple sequence alignments of three conserved domains in ORF1 product and capsid protein reveal a close relationship of P1AMV to papaya mosaic virus and clover yellow mosaic virus. The P1AMV genomic RNA and a major subgenomic RNA (sgRNA) of 0.9 kb have been detected in infected leaves by Northern blot hybridization. The latter sgRNA is the messenger for virus capsid protein and its 5' terminus has been located 23 nucleotides upstream of the initiator codon of the coat protein gene. The P1AMV virion RNA and RNA transcript resembling the 0.9 kb sgRNA have been translated in vitro giving rise to a single major 170K product and a major 22K product, respectively.

The occurrence of mixed infections of turnip mosaic, cauliflower mosaic and cucumber mosaic viruses in winter oilseed rape from the territory of Uzbekhistan

Turnip mosaic, cauliflower mosaic and cucumber mosaic viruses (TuMV, CaMV and CMV) were isolated and identified from winter oilseed rape plants from Uzbekhistan. This is the first record on the occurrence of CaMV and of mixed infection of rape with the three aforementioned viruses from the territory of the former Soviet Union.

Poa semilatent virus, a hordeivirus having no internal polydisperse poly(A) in the 3' non-coding region of the RNA genome

RNA from the Hungarian isolate of poa semilatent virus (PSLV) directed in vitro synthesis of 120K, 75K, 25K (coat protein) and 20K polypeptides. In vitro translation of PSLV RNA was blocked by the cap analogue, m7Gpp, thus suggesting that the virus RNA was capped. PSLV RNA could be aminoacylated with [14C]tyrosine in vitro. The sequence of 1.5 kb from the 3' end of the PSLV RNA gamma component revealed two open reading frames (ORFs) separated by a uridine-rich intergenic region. The putative product of the incomplete 5'-proximal ORF showed a close amino acid sequence similarity with the C-terminal segment of the gamma a protein (putative RNA replicase) encoded in the barley stripe mosaic virus (BSMV) RNA gamma, and the 20K product of the 3'-proximal ORF was found to be related to the 17K gamma b product of BSMV. The sequence of 0.8 kb from the 3' end of PSLV RNA beta encompassed two (incomplete) overlapping ORFs whose putative products are related to the beta c and beta d proteins encoded in the similarly arranged ORFs of BSMV RNA beta. Nucleotide sequence homology between the respective parts of the two hordeivirus genomes was restricted to the ORF for gamma a, the spacer between the ORFs for gamma a and gamma b, and the 3' non-coding region, particularly the 95 nucleotide segment at the 3' end representing a tRNA-like structure. Despite limited sequence conservation beyond this segment, the entire 3' non-coding region of PSLV RNA could be folded in a tight pseudoknotted structure closely resembling that of BSMV RNA. Surprisingly, the 'signature' sequence typical for BSMV RNA, internal polydisperse poly(A) intercalated between the coding part of the 3' tRNA-like structure, was not detected in the PSLV genome. Instead, the virus RNA contained several oligoadenylate stretches spaced by other residues, close to the junction of its coding and 3' non-coding portions.

[Effects of streptozotocin on the significance of body temperature variations in rats]

Experiments on rats have shown that the difference between depth and surface temperatures delta t of the normal organism in usual and variable external temperature conditions varies with in determined limits. The determination of delta t is proposed as a non-invasive test for the diagnosis of diabetes mellitus.

[Excretory function of the kidneys during artificial circulation in patients operated on for acquired heart defects]

The authors have shown that the suppression of the excretory function of the kidneys during the period of artificial circulation is considerably dependent on the concentration of vasopressin in blood and the associated spasm of renal vessels. The use of morphine as the main medicine for general anesthesia with the dose of 3 mg/kg as compared with the dose 2 mg/kg, gives less level of vasopressin in blood and thus reduces symptoms of antidiuresis in response to the action of strong stressogenic factors.

[Development of clinical physiology in heart surgery]

The article deals with the analysis of the monograph Evaluation of Performance and Analysis of Cyclic Work of the Heart written by B. A. Konstantinov, V. A. Sandrikov, and V. F. Yakovlev. It discusses the possible mechanism of the maintenance of the stability of hemodynamic indices--switching into action the contractions of nonfunctioning cardiomyocytes (the factor of functional heterogeneity).

[Ion-balanced cardioplegic solutions in cardiac surgery]

A comparative analysis of effectiveness of anti-ischemic defense of the myocardium performed in operations on the heart in 128 patients has shown that use of ion-balanced solutions is preferential since it allows reducing intrahospital lethality related with acute cardiac insufficiency from 13.3% to 6.3%.

[Relation between the suitability of the pancreas for transplantation and the structure of its blood vessels]

The pancreas from 111 corpses of persons, male and female, at the age of 16-92 years with various pathology has been investigated. The pancreatic blood vessels are injected with protacryl and undergone subsequent corrosion. The correlative and regressive analyses of the measurements reveal that age, height, character of pathology influence the state of the pancreatic blood vessels. It is recommended to observe the following conditions for choosing the donor of the pancreas graft: age under 35, middle height (especially for women), absence of corporal comotion and vast trauma, that essentially influence the vessels (causing spasm, disturbed integrity of the vascular wall), angiographic control conducted during washing or perfusion of the graft vascular bed.

[Surgical procedure in complicated mitral stenosis]

The experience with the surgical treatment of complicated forms of mitral stenosis in 110 patients with the III and IV classes of the disease according to the classification of the New York Heart Association was analyzed. Closed mitral commissurotomy was performed in 36 patients, opened commissurotomy--in 33 patients, prosthetics of the mitral valve was made in 41 patients. Closed mitral commissurotomy is believed to be the simplest method of correction of the duct in mild calcinosis and deformity of the mitral valve, and fixed thrombosis of the left auricle. Opened mitral commissurotomy was justified in case of thrombosis of the left auricle and mild calcinosis and deformity of the valve. Substitution of the valve is indicated in cases of massive calcinosis and rough deformity of the valve and subvalvular structures when valve-preserving operations are impossible.

[Optical rotatory dispersion by 5 viruses of the tobacco mosaic virus group and their components]

Optical rotatory dispersion (ORD) spectra in 250 to 350 nm region were measured for preparations of five TMV-like viruses (TMV vulgare, HR and U2 strains of TMV dolihosenation mosaic virus and cucumber virus 4) and also for RNA and protein preparations of these viruses. The data obtained testify against the possibility that the double peak with maxima at 286 and 293 nm observed in ORD of all the five viruses is due to interaction of tryptophan residues in virus coat protein with the RNA of the virul particle. The spectra of intravirus RNA of the five viruses, calculated as the difference between ORD of the intact virus and of its coat protein, were found to differ significantly from each other and from ORD of free RNA. ORD spectra of hybrid viruses, reconstituted from RNA of one virus and coat protein of another, proved to be identical to the ORD of the virus, whose protein was used in reconstitution. We suppose that the difference in ORD of the intravirus RNA of the five viruses reflect differences of RNA-protein interactions in them.