Screening for preeclampsia in the first trimester of pregnancy in routine clinical practice in Hungary

We aimed to evaluate the contribution of different factors in the Fetal Medicine Foundation algorithms for preeclampsia (PE) risk calculation during first-trimester screening in Hungary. We selected subjects for the nested case-control study from a prospective cohort of 2545 low-risk pregnancies. Eighty-two patients with PE and 82 gestational age-matched controls were included. Individual PE risk was calculated using two risk-assessing softwares. Using Astraia 2.3.1, considering maternal characteristics and biophysical parameters only, detection rates (DR) were 63.6% for early-PE and 67.6% for late-PE. When we added placenta associated plasma protein A (PAPP-A) to the risk calculation, DRs decreased to 54.5% and 64.8% respectively. Using Astraia 2.8.2 with maternal characteristics and biophysical parameters resulted in the DRs of 63.6% (early-PE) and 56.3% (late-PE). If we added PAPP-A to the risk calculation, DRs improved to 72.7% and 54.9%. The addition of placental growth factor (PlGF) did not increase detection rates in either calculation. In conclusion, using maternal characteristics, biophysical parameters, and PAPP-A, an acceptable screening efficacy could be achieved for early-PE during first-trimester screening. Since PlGF did not improve efficacy in our study, we suggest setting new standard curves for PlGF in Eastern European pregnant women, and the evaluation of novel biochemical markers.

Integrated Systems Biology Approach Identifies Novel Maternal and Placental Pathways of Preeclampsia

Preeclampsia is a disease of the mother, fetus, and placenta, and the gaps in our understanding of the complex interactions among their respective disease pathways preclude successful treatment and prevention. The placenta has a key role in the pathogenesis of the terminal pathway characterized by exaggerated maternal systemic inflammation, generalized endothelial damage, hypertension, and proteinuria. This sine qua non of preeclampsia may be triggered by distinct underlying mechanisms that occur at early stages of pregnancy and induce different phenotypes. To gain insights into these molecular pathways, we employed a systems biology approach and integrated different “omics,” clinical, placental, and functional data from patients with distinct phenotypes of preeclampsia. First trimester maternal blood proteomics uncovered an altered abundance of proteins of the renin-angiotensin and immune systems, complement, and coagulation cascades in patients with term or preterm preeclampsia. Moreover, first trimester maternal blood from preterm preeclamptic patients in vitro dysregulated trophoblastic gene expression. Placental transcriptomics of women with preterm preeclampsia identified distinct gene modules associated with maternal or fetal disease. Placental “virtual” liquid biopsy showed that the dysregulation of these disease gene modules originates during the first trimester. In vitro experiments on hub transcription factors of these gene modules demonstrated that DNA hypermethylation in the regulatory region of ZNF554 leads to gene down-regulation and impaired trophoblast invasion, while BCL6 and ARNT2 up-regulation sensitizes the trophoblast to ischemia, hallmarks of preterm preeclampsia. In summary, our data suggest that there are distinct maternal and placental disease pathways, and their interaction influences the clinical presentation of preeclampsia. The activation of maternal disease pathways can be detected in all phenotypes of preeclampsia earlier and upstream of placental dysfunction, not only downstream as described before, and distinct placental disease pathways are superimposed on these maternal pathways. This is a paradigm shift, which, in agreement with epidemiological studies, warrants for the central pathologic role of preexisting maternal diseases or perturbed maternal–fetal–placental immune interactions in preeclampsia. The description of these novel pathways in the “molecular phase” of preeclampsia and the identification of their hub molecules may enable timely molecular characterization of patients with distinct preeclampsia phenotypes.

Endoscopic Placental Laser Coagulation in Monochorionic Diamniotic Twins with Type II Selective Fetal Growth Restriction

Objective: To determine predictors of survival in monochorionic diamniotic twins with selective fetal growth restriction type II (sFGR-II), with or without twin-to-twin transfusion syndrome (TTTS), treated by endoscopic placental laser coagulation. Methods: Laser surgery was performed at 20 (15-27) weeks' gestation in 405 cases of sFGR-II with and 142 without coexisting TTTS. Multivariable logistic regression analysis was performed to determine significant predictors of survival to discharge from hospital. Results: There was survival of the small twin in 216 (39.5%) and of the large twin in 379 (69.3%) cases. Significant predictors of survival of both the small and larger twin were ductus venosus Doppler findings in the small twin, gestational age at laser and cervical length, but not the presence of TTTS or Doppler findings in the large twin. Conclusions: In sFGR-II, survival after laser surgery is primarily dependent on the condition of the small twin.

Constructing STR multiplexes for individual identification of Hungarian red deer

Red deer is the most valuable game of the fauna in Hungary, and there is a strong need for genetic identification of individuals. For this purpose, 10 tetranucleotide STR markers were developed and amplified in two 5-plex systems. The study presented here includes the flanking region sequence analysis and the allele nomenclature of the 10 loci as well as the PCR optimization of the DeerPlex I and II. LD pairwise tests and cross-species similarity analyses showed the 10 loci to be independently inherited. Considerable levels of genetic differences between two subpopulations were recorded, and F(ST) was 0.034 using AMOVA. The average probability of identity (PI(ave)) was at the value of 2.6736 × 10(-15). This low value for PI(ave) nearly eliminates false identification. An illegal hunting case solved by DeerPlex is described herein. The calculated likelihood ratio (LR) illustrates the potential of the 10 red deer microsatellite markers for forensic investigations.

Measuring expression levels of small regulatory RNA molecules from body fluids and formalin-fixed, paraffin-embedded samples

MicroRNAs are involved in the regulation of various pathophysiological processes such as immune regulation and cancer. Next-generation sequencing methods enable us to monitor their presence in various types of samples but we need flexible methods for validating datasets generated by high-throughput methods. Here we describe the detailed protocols to be used with our MiRNA Primer Design Tool assay design system. The presented methods allow the flexible design of the oligonucleotides needed for the RT-qPCR detection of any variant of small regulatory RNA molecules from virtually any species. This method can be used to measure miRNA levels from formalin-fixed, paraffin-embedded (FFPE) samples and various body fluids. As an example, we show the results of the hsa-miR-515-3p, hsa-miR-325, and hsa-miR-155 quantification using a specific UPL probe (Universal Probe Library) and a stem-loop RT-qPCR assay. The small nucleolar RNA RNU43 is used as endogenous control for normalization of the results. Urine from healthy pregnant women and FFPE samples from patients diagnosed with colorectal cancer and treated with antibody-based anti-EGFR monotherapy were used as samples.

From excitonic to photonic polariton condensate in a ZnO-based microcavity

We report exciton-polariton condensation in a new family of fully hybrid ZnO-based microcavity demonstrating the best-quality ZnO material available (a bulk substrate), a large quality factor (~4000) and large Rabi splittings (~240 meV). Condensation is achieved between 4 and 300 K and for excitonic fractions ranging between 17% and 96%, which corresponds to a tuning of the exciton-polariton mass, lifetime, and interaction constant by 1 order of magnitude. We demonstrate mode switching between polariton branches allowing, just by controlling the pumping power, to tune the photonic fraction by a factor of 4.

In utero incarceration of congenital diaphragmatic hernia

In utero diagnosis of incarcerated congenital diaphragmatic hernia has never been reported. In our case, congenital diaphragmatic hernia presented at 34 weeks of gestation with dilated bowel loops, pleural effusion, and ascites on fetal ultrasound. Preterm delivery and emergency exploration revealed a tight posterolateral diaphragmatic defect with extensive bowel infarction.

A comparison of two-point, three-point and deletion mapping in the C cistron of rhizobiophage 16-3, with an explanation for the recombination pattern

A general tendency for additivity prevailed in recombination frequencies for two-point fine-structure mapping of 14 mutants in the C cistron of Rhizobium meliloti phage 16-3, with little evidence of any marker effect. Intracistronic three-point mapping indicated that double crossovers are rare. Deletion mapping indicated that the two- and three-point mapping data gave the correct order of the mutations. A high frequency (5 to 8%) of c/c(+) heterozygotic phage progenies was observed in standard crosses. This pattern implies formation of a relatively long region of heterozygosity. Together with the results of the three-point tests, it suggests certain properties of the branch migration and resolution steps envisioned in current mechanisms of recombination.

Methods for Analysis of the C Cistron of Temperate Phage 16-3 of RHIZOBIUM MELILOTI

A series of clear mutants of the temperate phage 16-3 of Rhizobium meliloti were isolated that included various point and deletion mutants of the C cistron, coding for the phage repressor. It was observed that recombinant genotypes, such as c(+) and ti (temperature-sensitive allele), which form turbid plaques, can be detected quantitatively as lysogenic colonies and scored even at frequencies as low as 10(-6). Point mutations, deletions and the autonomy of intracistronic second-site mutations were characterized by this method. Further analysis has shown that each possible pair from three ti mutants gave nonconditional clear recombinants. It was shown that these latter bear the two initial ti mutations, suggesting a cumulative effect of two conditional mutations on the structure of the repressor protein. The double mutants were utilized in fine-structure mapping of the C cistron.

Prevalence and avidity of human herpesvirus-6 specific IgG antibodies in pregnant women in Hungary

The prevalence, the level and the avidity of human herpesvirus-6 (HHV-6) specific IgG were examined in pregnant women and age-matched female blood donors. The study group consisted of 180 women (age 14-45); 60 women with normal pregnancy, 60 pregnant women with fetuses suspected of having any viral infection and 60 healthy blood donors with no history of pregnancy. Plasma or serum samples were tested for HHV-6 IgG antibodies by an immunofluorescence assay. Ninety-eight percent of blood donors and 97% of 120 pregnant women had IgG antibodies to HHV-6. The rate of seropositivity in women with normal pregnancies and women with fetuses suspected to have viral infection was the same. Pregnant women (n = 120) had significantly lower antibody titer than blood donors. No significant differences were found in the same respect between the two groups of pregnant women. Low avidity of IgG antibodies to HHV-6 was detected in 5% of pregnant women.

Integrative plasmid vector for constructing single-copy reporter systems to study gene regulation in Rhizobium meliloti and related species

The integrative system of phage 16-3 of Rhizobium meliloti 41 was shown to function in several bacterial species belonging to the Rhizobium, Bradyrhizobium, Azorhizobium, and Agrobacterium genera. It might also function in many other bacterial species provided that both the target site (attB) and the required host factor(s) are present. Here we report on the construction of a new integrative vector that can be utilized in gene regulation studies. It provides an opportunity to create a single-copy set-up for characterizing DNA-protein interactions in vivo, in a wide range of bacteria. To demonstrate the usefulness of the vector, transcription repression by binding of the C repressor protein of phage 16-3 to wild type operators was studied. The assay system provided highly reproducible quantitative data on repression.

[Complications of laparoscopic cholecystectomy]

Number of bile duct injuries is rising with the spreading of laparoscopic cholecystectomy. Authors analyse the complications in the last 8 years, especially the bile duct injuries. During this period 1657 laparoscopic cholecystectomies were performed. Complication occurred in 28 cases during the intra- and postoperative period (1.68%). Main bile duct injury was detected in 7 cases (0.42%), while leakage from a Luschka's duct appeared in 10 patients. Three bleeding complications, 2 injuries of the duodenum and in 3 cases severe intraabdominal infection was observed. Four patients died (0.24%).

[Clinical importance of assessment of collateral capacity in the circle of Willis. Benefit of a mathematical blood flow model for the every-day practice of vascular surgery]

Collateral capacity of the Willisian arteries is of clinical importance during and after carotid endarterectomies.

AIMS

Assessment of cerebral hemodynamics using a flow circulation model based on a mathematical formula.

PATIENTS AND METHODS

Four patients suffering from ischemic stroke in moribund stage were investigated using transcranial color-coded duplex sonography. By compressing the common carotid arteries, the function of the Willisian collaterals was assessed. After the death of the patients, the circles were removed, the diameters and lengths of the arterial segments were measured. The data were analysed with the mentioned circulation model.

RESULTS

The diameters of non-functioning collateral arteries were 0.4 mm, while that of the functional ones were 0.7 and 0.8 mm, respectively. In the two cases where the anterior communicating arteries did not function, a near-critical hemodynamical status was found in the end-arteries. This was especially true if the mean arterial blood pressure was 70 mmHg. The most critical hemodynamical status developed in case 4, where internal carotid occlusion on one side, a contralateral severe carotid stenosis and a non-functioning anterior communicating artery were observed.

CONCLUSIONS

A special flow circulation model based on mathematical formula enables the calculation of the cerebral blood flow in the different arterial segments of the circle of Willis. Further studies are needed to clarify whether the method can be used for preoperative modeling of the cross-clamping phase of carotid endarterectomy.

Footprinting studies of specific complexes formed by RepA, a replication initiator of plasmid pCU1, and its binding site

The basic replicon of plasmid pCU1 contains three different replication origins. Replication initiated from the oriB origin requires pCU1-encoded protein RepA. Previously, information analysis of 19 natural RepA binding sequences predicted a 20-bp sequence as a RepA binding site. Guanines contacting RepA in the major groove of DNA have also been determined. In this study, we used the missing-nucleoside method to determine all of the bases relevant to RepA binding. The importance of some thymine bases was also confirmed by a missing-thymine site interference assay. Participation of the 5-methyl groups of two thymines (at positions -6 and 7) in RepA binding was pointed out by a missing-thymine methyl site interference assay. Phosphate groups of the DNA backbone which strongly interfered with RepA binding upon ethylation were also identified. The pattern of contacting positions mapped by hydroxyl radical protection footprinting indicates that RepA binds to one face of B-form DNA. The length of the binding site was found to be 20 bp by dissociation rate measurement of complexes formed between RepA and a variety of binding sequences. The symmetry of the binding site and that of the contacting bases, particularly the reacting 5-methyl groups of two thymines, suggest that pCU1-encoded RepA may contact its site as a homodimer.

Trp22, Trp24, and Tyr8 play a pivotal role in the binding of the family 10 cellulose-binding module from Pseudomonas xylanase A to insoluble ligands

Aromatic amino acids are believed to play a pivotal role in carbohydrate-binding proteins, by forming hydrophobic stacking interactions with the sugar rings of their target ligands. Family 10 cellulose-binding modules (CBM10s), present in a number of cellulases and xylanases expressed by Pseudomonas fluorescens subsp. cellulosa, contain two tyrosine and three tryptophan residues which are highly conserved. To investigate whether these amino acids play an important role in the interaction of CBM10 from P. fluorescens subsp. cellulosa xylanase A (Pf Xyn10A) with cellulose, each of these residues was changed to alanine in CBM10 expressed as a discrete module or fused to the catalytic domain of Pf Xyn10A (CBM10-CD), and the capacity of the mutant proteins of CBM10-CD to bind the polysaccharide was evaluated. The data showed that W22A, W24A, and Y8A bound very weakly to cellulose compared to the wild-type protein, while Y12A retained its capacity to interact with the glucose polymer. When the W7A mutation was introduced into CBM10 the protein domain did not accumulate in Escherichia coli. In contrast, the W7A mutant of CBM10-CD was efficiently expressed in E. coli, although the protein bound very weakly to cellulose. NMR spectra of wild-type CBM10, W22A, and W24A were very similar, suggesting that the mutations did not significantly affect the protein fold. Titration of wild-type CBM10, W22A, and W24A with N-bromosuccinimide indicated that Trp22 and Trp24 were on the surface of the protein, while Trp7 was buried. Collectively, these data indicate that Trp22, Trp24, and Tyr8 play a direct role in the binding of Pf Xyn10A CBM10 to cellulose. The results are discussed in the light of the three-dimensional structure of CBM10 [Raghothama, S., Simpson, P. J., Szabó, L., Nagy, T., Gilbert, H. J., and Williamson, M. P. (2000) Biochemistry 39, 978-984].

Phage abortive infection of Bacillus licheniformis ATCC 9800; identification of the abiBL11 gene and localisation and sequencing of its promoter region

The virulent bacteriophage BL11 infects almost all Bacillus licheniformis strains tested, including the industrial bacitracin-producing B. licheniformis 19. B. licheniformis ATCC 9800, however, was virtually insensitive to phage BL11 infection, and all of the few surviving progeny phages proved to be mutants. The phage-resistance mechanism was neither inhibition of adsorption, nor restriction or exclusion provided by a resident prophage, but was, instead, of another type. Phage BL11 adsorbed well on to ATCC 9800 cells, its DNA was injected, but replication of phage DNA was inhibited and the infected cells died. Thus, the mechanism of phage resistance was identified as abortive infection (AbiBL11). The so-called abiBL11 gene was identified on the chromosome of strain ATCC 9800 by Tn917PF1 transposon mutagenesis. Part of the abiBL11 gene from the phage-sensitive ATCC 9800::Tn917PFI was cloned. Gene-disruption analysis, based on Campbell-type integration, showed that a 0.3-kb EcoRI fragment contained the 5' end of abiBL11. The promoter region of abiBL11 was identified using promoter- and terminator-probe plasmids. The deduced sequence (206 amino acids) of the N-terminal part of abiBL11 showed no significant homology to known abortive-infection genes, but did show homology to a Saccharomyces cerevisiae gene coding for a serine/threonine protein kinase (RCK1).

Interaction of Azospirillum lipoferum with wheat germ agglutinin stimulates nitrogen fixation

In vitro, the nitrogen fixation capability of A. lipoferum is efficiently increased in the presence of wheat germ agglutinin (WGA). A putative WGA-binding receptor, a 32-kDa protein, was detected in the cell capsule. The stimulatory effect required N-acetyl-D-glucosamine dimer (GlcNAcdi) terminated sugar side chains of the receptor and was dependent on the number of GlcNAcdi links involved in receptor-WGA interface. Binding to the primary sugar binding sites on WGA had a larger stimulatory effect than binding to the secondary sites. The WGA-receptor complex generated stimulus led to elevated transcription of the nifH and nifA genes and of the glnBA gene cluster but not of the glnA gene from its own promoter. There may well be a signalling cascade contributing to the regulation of nitrogen fixation.

Identification of site-specific recombination genes int and xis of the Rhizobium temperate phage 16-3

Phage 16-3 is a temperate phage of Rhizobium meliloti 41 which integrates its genome with high efficiency into the host chromosome by site-specific recombination through DNA sequences of attB and attP. Here we report the identification of two phage-encoded genes required for recombinations at these sites: int (phage integration) and xis (prophage excision). We concluded that Int protein of phage 16-3 belongs to the integrase family of tyrosine recombinases. Despite similarities to the cognate systems of the lambdoid phages, the 16-3 int xis att system is not active in Escherichia coli, probably due to requirements for host factors that differ in Rhizobium meliloti and E. coli. The application of the 16-3 site-specific recombination system in biotechnology is discussed.

Isolation of a beta-galactosidase-encoding gene from Bacillus licheniformis: purification and characterization of the recombinant enzyme expressed in Escherichia coli

The Bacillus licheniformis beta-galactosidase gene, lacBl, was cloned on a 5.8-kb HindIII fragment into pBR322 and expressed by its own promoter in Escherichia coli. Deletion and complementation analysis showed that the enzyme-encoding region was located on a 4. 1-kb HindIII-ClaI fragment. The transcription region for the lacBl was identified on this fragment with promoter- and terminator-probe plasmids. The deduced sequence of 149 aa of the N-terminal part of lacBl showed aa sequence homology with beta-Gal from B. stearothermophilus, B. circulans, Haloferax alicantei, Clostridium perfringens, Arthrobacter sp.. No significant homology was shared with those found in the lacZ and lacS families. The recombinant beta-galactosidase (LacB1) was purified by FPLC. The molecular mass of the enzyme (80 kDa) and its optimal pH (5.7) and temperature (45 degrees C) were determined.

All three surface tryptophans in Type IIa cellulose binding domains play a pivotal role in binding both soluble and insoluble ligands

The three surface tryptophans of the Type IIa cellulose binding domain of Pseudomonas fluorescens subsp. cellulosa xylanase A (CBD(XYLA)) were independently mutated to alanine, to create the mutants W13A, W49A and W66A. The three mutant proteins were purified, and their capacity to bind to a variety of ligands was determined. The mutant proteins have native-like structures but exhibited much weaker affinity for crystalline and amorphous cellulose and for cellohexaose than the wild type. These data indicate that all three tryptophans are important for binding to cellulose, and support a model in which the three tryptophans form an aromatic strip on the surface of the protein that binds to a single cellulose.

[Assessment of cerebrovascular reactivity in patients with symptomatic and asymptomatic atherosclerotic carotid artery lesions]

AIMS

Strokes caused by hemodynamically significant internal carotid artery stenoses and occlusions are believed to be embolic or hemodynamic of origin. The aim of the study was to assess cerebral hemodynamic compromises of significant carotid artery stenosis of occlusion using vasodilatory testing (acetazolamide test) in asymptomatic and symptomatic patients.

PATIENTS AND METHODS

36 patients with unilateral, hemodynamically significant carotid stenosis were investigated using transcranial Doppler acetazolamide-test. There were 12 asymptomatic and 24 symptomatic patients. The middle cerebral artery mean blood flow velocity was measured at rest and after intravenous injection of 1 g acetazolamide. The absolute mean blood flow velocities and the cerebrovascular reactivity was compared at the stenotic and non-stenotic side. In a further analysis the mean velocities and the cerebrovascular reactivity values of the stenotic side were compared. Results of acetazolamide test performed on 28 healthy volunteers were used as control values.

RESULTS

There were no side-differences between the middle cerebral artery mean blood flow velocity and cerebrovascular reactivity values in the asymptomatic group. In the symptomatic group, however middle cerebral artery mean velocity and cerebrovascular reactivity after acetazolamide was significantly lower on the stenotic side, than on the non-stenotic one. Comparing the different groups non-stenotic sides did not differ to each other in their cerebral blood flow velocity and cerebrovascular reactivity. In the symptomatic patients, however, cerebral blood flow velocity and cerebrovascular reserve capacity after acetazolamide was lower, than that of the stenotic side of asymptomatic patients and controls.

CONCLUSIONS

The transcranial Doppler is a suitable method for detecting altered cerebral hemodynamics in significant carotid stenosis. Impaired cerebrovascular reactivity may refer to the impairment of cerebral autoregulatory mechanisms.

Integrative promoter cloning plasmid vectors for Rhizobium meliloti

A set of integrative 'promoter probe' plasmids were constructed for both translational and transcriptional fusions. The vectors are based on the broad host range, low copy number plasmid pRK290 (IncPl) in which the attachment site of Rhizobium phage 16-3 and the lacZ gene of Escherichia coli were combined. The vectors integrate into the chromosome of Rhizobium meliloti, providing also the advantages of the single copy promoter probe cassettes. Thus they fulfil the prerequisite of the systems used for investigating gene regulation. The plasmids were applied for the study of the transcription regulation of the 16-3 phage. Their versatile use is also demonstrated.

[Prenatal ultrasonic diagnosis of cleft lips and palates]

The purpose of this communication is to demonstrate the possibility of prenatal diagnosis of cleft lips and palates by routine ultrasound screening. As obstetrical ultrasound improves, anomalies of the fetal face can be diagnosed more and more frequently in utero. From 1991 to 1994 9 cases with cleft face syndrome were detected prenatally. In 8 cases the presence of cleft lip and palate was isolated. In one case the cleft lip and palate was associated with phocomelia. In cases with cleft palate the widening of nasal cavity was observed. In cases with bilateral cleft palate polyhydramnions were observed twice and undulating movements of the tongue were also seen.

The bacterial attachment site of the temperate Rhizobium phage 16-3 overlaps the 3' end of a putative proline tRNA gene

Bacteriophage 16-3 inserts its genome into the chromosome of Rhizobium meliloti strain 41 (Rm41) by site-specific recombination. The DNA regions around the bacterial attachment site (attB) and one of the hybrid attachment sites bordering the integrated prophage (attL) were cloned and their nucleotide sequences determined. We demonstrated that the 51 bp region, where the phage and bacterial DNA sequences are identical, is active as a target site for phage integration. Furthermore it overlaps the 3' end of a putative proline tRNA gene. This gene shows 79% similarity to the corresponding proline tRNA-like genomic target sequence of certain integrative plasmids in Actinomycetes.

Stable incorporation of genetic material into the chromosome of Rhizobium meliloti 41: construction of an integrative vector system

An integrative vector system has been developed from the site-specific recombination elements of temperate phage 16-3. The system can be used for highly efficient stable introduction of genetic material into the chromosome of the symbiotic nitrogen-fixing organism, Rhizobium meliloti 41 (Rm41) at the attB site. Vectors carrying the phage-borne attachment site were constructed, and helper phages providing the site-specific recombination functions in trans were isolated. Other possible applications of the system are discussed.

The isolated N-terminal DNA binding domain of the c repressor of bacteriophage 16-3 is functional in DNA binding in vivo and in vitro

The 197 amino acid c repressor of the temperate Rhizobium meliloti phage 16-3 still regulates the OR operator of the phage after removal of its carboxyl terminal region. When cloned in the low-copy-number plasmid pGA46, a severely truncated variant (R1-77), which retains only the first 77 amino acids of the intact protein, repressed in vivo transcription from the phage promoter PR. When the R1-77 repressor was fused to E. coli beta-galactosidase, the hybrid protein bound OR operator DNA in vitro. The behavior of fusion proteins derived from a point mutant is consistent with the assignment of DNA binding specificity to the amino-terminal region. Furthermore two repressor alleles bearing ts mutations that mapped in the R1-77 region (near a helix-turn-helix motif) were also temperature sensitive for regulation of the OR site, while an 18 bp "in frame" deletion mutant, which mapped in the carboxyl terminal segment, regulated the OR operator in wild-type fashion. The carboxyl terminal region of the repressor is however necessary for the control of lysogenic development of 16-3.

[Infectious diseases and hemostasis]

Authors survey the most significant haemostatic complications (thrombocytopenia, DIC, vasculitis, thrombotic microangiopathy) as well as their immune and non-immune pathogenesis in infectious diseases. A short summary of therapeutic facilities and the infectious hazards of blood component therapy is also given.

[Protein C and apoprotein levels in ischemic heart disease diagnosed by coronarography]

The levels of protein C and different lipid parameters were measured in 22 patients, younger than 50 years, suffering from coronary heart disease, proved previously by angiography. The severity of coronariasclerosis showed certain correlation with the concentration of apolipoprotein B and triglycerids, while low levels of protein C were also mainly observed in those with severe coronary heart disease.

[Connection between plasma thromboxane and prostacyclin levels in the metabolic control of diabetic children]

Platelet poor plasma thromboxane and prostacyclin levels and the quantity of metabolic control, altogether with vascular complications were evaluated in 55 children diabetes mellitus. The control group consisted of 33 healthy children of the similar age. Thromboxane levels remained unchanged in diabetics, while prostacyclin proved to be significantly decreased, which resulted in greater thromboxane/prostacyclin ratio. No meaningful differences were found according to the presence or absence of vascular complications in this group of diabetics. A positive correlation could have been detected between glycosylated haemoglobin and thromboxane levels, while a negative one between glycosylated haemoglobin and prostacyclin levels. The alterations of prostaglandin metabolism may be regarded as a consequence of diabetic metabolic changes, rather than of vascular complications. Disturbed prostaglandin metabolism in diabetic children might have a role in the pathogenesis of vascular complications.

PMAP, PMAPS: DNA physical map constructing programs

Computer programs are described, which facilitate the construction of the restriction site (physical) map of DNA molecules. By knowing the length of each fragment and its degree of error in the single and the double restriction enzyme digestions, the programs give all the possibilities for the physical map. This method is applicable to linear DNA molecules. Several examples are presented which indicate the high efficiency of the programs in constructing restriction site maps for the 62 Kb chromosome of bacteriophage 16-3. We have constructed complex maps (i.e. EcoRI map with 16 and EcoRV with 11 fragments).

Cyclic AMP-dependent constitutive expression of gal operon: use of repressor titration to isolate operator mutations

When the gal operator region is present in a multicopy plasmid it binds to all ("titrates") the gal repressor and "induces" the chromosomal gal operon. To make operator mutations (Oa) with reduced affinity toward the repressor, plasmid DNA was irradiated with UV light and mutant derivatives were isolated that were unable to release the chromosomal gal genes from repression. Then with such an Oa plasmid operator revertants were isolated that had reacquired the ability to release repression. Both sets of mutations have been localized by DNA sequence analysis. When the Oa mutations were transferred from the plasmid to the chromosome by recombination these mutant operators were found to make gal expression constitutive (independent of repressor) but still dependent on cAMP, whereas the previously reported gal operator mutants (Oc) are constitutive both in the presence and in the absence of cAMP. The titration method of isolating mutants enables the isolation of strains with operator mutations that also affect normal promoter activity, and it provides an easy way to isolate revertants of operator mutations.

A control element within a structural gene: the gal operon of Escherichia coli

The gal operon of Escherichia coli is transcribed from two overlapping promoters, PG1 and PG2. Cyclic AMP and its receptor protein (CRP) modulate the two promoters in opposite directions by binding to a single cat locus. Both the promoters are negatively regulated by a single repressor, the product of the galR gene. An operator site, defined by several mutations, has previously been located upstream from the cat locus. We have isolated and characterized a new set of cis-dominant constitutive mutations of the gal operon and determined their locations by DNA sequencing. From these studies, we propose the existence of a second functional gal operator element at an extraordinary site--within galE, the first structural gene. Both the operators, OE (exterior) and OI (interior), are involved in the repression of PG1 and PG2. This would be the first example of the presence of a functional operator element within a structural protein-coding region.

Recombination deficient mutants of Rhizobium meliloti 41

Two mutants deficient in homologous genetic recombination have been isolated from Rhizobium meliloti 41 after Tn5 mutagenesis. Both mutants are defective in the induction of temperate phage 16-3 by UV-light, Mytomycin-C or Bleomycin, their UV sensitivity is more pronounced than that of the wild-type strain, and they lack the 'SOS activity' responsible for induced mutations.

The detailed physical map of the temperate phage 16-3 of Rhizobium meliloti 41

Restriction cleavage maps for enzymes EcoRI, BamHI, PstI, PvuII, XbaI and EcoRV of Rhizobium meliloti temperate phage 16-3 have been established. Together with the earlier maps (HindIII, KpnI, HpaI, BglII) 98 restriction sites, 'evenly' distributed, have been mapped along the phage genome, including the so far unmarked silent region of the chromosome. All the restriction maps have been fitted to each other by computer optimalization. Beyond for conventional techniques a computer program (PMAP) for physical mapping of linear DNA has been employed which made the experimentation, in several cases, extremely efficient.

Identification of structural proteins of Rhizobium meliloti temperate phage 16-3

The structural proteins of Rhizobium meliloti temperate phage 16-3 have been analysed by means of polyacrylamide gel electrophoresis, isoelectric focusing and agarose gel electrophoresis. Five major and five minor proteins were identified and characterized with respect to their size, isoelectric point and their distribution between the head ad tail of the phage particle. The synthesis of structural proteins was studied by one- and two-dimensional gel electrophoresis.

Correlation between map position and phenotype of CTI mutants in the c cistron of Rhizobium meliloti phage 16-3

Nine temperature-sensitive clear mutations (Cti) in the C cistron (coding for the repressor protein) of Rhizobium meliloti temperate phage 16-3 were characterized according to the inductive temperature, the immunity of cells lysogenic for these mutant phages to superinfection by homoimmune weak virulent mutants, the phenotype of double-ti mutants and interallelic complementation. The results indicate that mutations of similar phenotypic expression are clustered on the genetic map. Furthermore, it seems probable that the C cistron of the original phage 16-3 is identical to that of the independently isolated phage strain 36.

Heterozygosis of phage 16-3 of Rhizobium meliloti: moderate level of mismatch repair or gene conversion

Analysis of clear/turbid mottled (heterozygotic plaques) of Rhizobium meliloti temperate phage 16-3 indicates that the efficiency of repair at three sites (ti3, ti4, and ti5) in the C cistron is 2 to 20-fold less than that observed in E. coli phage lambda. In agreement with this conclusion, heterozygotic plaques were observed at similar frequency in crosses where point and small deletion mutants were combined, suggesting that in Rhizobium, DNA molecules with short single-stranded loops can escape from repair as efficiently as the simple mismatches.

Isolation and characterization of an R-prime plasmid from Rhizobium meliloti

Using a simple enrichment procedure, we isolated an R-prime derivative of plasmid R68.45 carrying a 17.8-megadalton segment of the Rhizobium meliloti 41 chromosome. The chromosomal segment carried on this plasmid (pGY1) includes the markers cys-24+, cys-46+, and att16-3. Plasmid pGY1 mobilized the chromosome in a polarized way starting from the region of homology, but cannot promote chromosome transfer from other sites. The att16-3 site on pGY1 allowed the integration of phage 16-3 into pGY1, and a composite plasmid of 91.8 megadaltons was formed. This vector (pGY2) is suitable for the introduction of Rhizobium bacteriophage 16-3 into other gram-negative bacteria.

Restriction mapping of DNA of temperate Rhizobium meliloti phage 16-3: comparison of genetic and physical maps indicates a long, genetically silent chromosomal arm

The complete restriction map of DNA (61.57 Kb) of temperate Rhizobium meliloti phage 16-3 has been constructed for enzymes BglII, HindIII, HpaI, KpnI, and a partial map for EcoRI. The strategy employed for mapping included the analysis of double, triple and partial digests; comparison of wild type and deletion mutants; and detailed analysis of subfragments, exploiting the presence of cohesive ends of the phage. Comparison of the genetic and physical maps indicates that one arm of the chromosome is genetically silent and/or contains nonessential genes.