Biomedical subjects
Publications and source records attributed to B Wróbel.
Authors presents the case of cancer transformation papilloma planoepithelial of lip into squamous cell carcinoma in 26-years old man. They give attention to necessity of radical remove all changes around the lips. It is especially important because of possibility of cancer transformation in every case of papilloma of lip.
The authors describe a tonsillolith detected by a 70-year-old man with odynophagy and a history of often tonsillar infections. A diagnosis of peritonsillar abscess was first made. The large concrement was yellowish-gray, measured 41 x 21 x 19 mm, which was one of the largest reported case in the world.
Production of the major capsid protein of SV40, VP1, is of great interest for the study on capsid assembly in vitro. Production of soluble His6-VP1 in Escherichia coli strains deficient in the GroELS chaperone machine was substantially higher than in the wild-type strain. The His6-VP1 produced in a groEL mutant strain was readily purified. The protein was able to form higher-order structures as evidenced by analysis of the soluble fraction by gel filtration, by sedimentation in sucrose gradient, and by electron microscopy. We propose the use of groE mutants for the production of the major capsid protein of SV40 and perhaps also other papovaviruses.
The oriJ-based plasmids contain the origin of DNA replication from the cryptic Rac prophage, present in the chromosomes of most Escherichia coli K-12 strains. The organization of the oriJ replication region resembles that of the bacteriophage lambda, although sequence similarity is small. Here we investigated the regulation of replication of the oriJ-based plasmid in E. coli relA(+) and relA(-) hosts during amino acid starvation and limitation, i.e., during the stringent and relaxed responses. We found that, contrary to plasmids derived from phage lambda, replication of the oriJ-based plasmid proceeds efficiently during both stringent and relaxed responses. On the other hand, density shift experiments and measurement of the stability of a putative replication initiator protein (the lambda O protein homologue) suggest that this replication may be carried out by the heritable replication complex, as previously demonstrated for lambda plasmids. We demonstrate that contrary to bacteriophage lambda p(R) promoter, an analogous promoter from the oriJ region is activated rather than inhibited at increased ppGpp levels. We propose that various responses of these promoters (p(R) and p(R-Rac), which are necessary for transcriptional activation of orilambda and perhaps oriJ, respectively) to ppGpp are responsible for differences in the replication regulation between orilambda- and oriJ-based plasmids during the stringent response.
The authors describe an unusually case of throat tumor and dyspnea in course of Elongated Styloid Process Syndrome. They pay attention to X-ray examination, including CT, in correct diagnosis.
Sarcoidosis is a disease of unknown etiology characterized by non-caseating granulomatous inflammation of various organs, but most frequently involving the lungs of young adults. Sarcoidosis is seldom seen by ear, nose, throat and larynx. The isolated case of sarcoidosis of the larynx is very rare. We present a case of histologically confirmed sarcoidosis of the vocal cord. The clinical aspects, diagnostic problems and therapeutical possibilities of this rare disease are described.
The authors describe a case of a man with a large choanal polyp descending into the hypopharynx. The man presented additional symptoms of full aspirin intolerance and pollinosis caused with grass pollen antigens. The Caldwell-Luc procedure was performed and the choanal polyp was successfully removed through the mouth. Postoperatively treatment with leukotriene antagonists and with an intranasal steroids with positive clinical effect was begun. However the patient discontinued the therapeutic process causing polyp recurrence within a short time.
We present evidence that biological properties of cell membranes are altered in dnaA and seqA mutants of Escherichia coli relative to wild-type bacteria. We found that bacteriophage lambda forms extremely large plaques on the dnaA seqA double mutants. On the single mutants, dnaA and seqA, the plaques are also bigger than those formed on the wild-type host. However, no significant differences in intracellular phage lambda development were observed between wild-type and mutant hosts, indicating that differences in burst size do not account for the observed differences in plaque size. On the other hand, more efficient release of the phage lytic proteins and/or higher sensitivity of the cell membranes to these proteins may result in more efficient cell lysis. We found that the efficiency of adsorption of bacteriophage lambda to the dnaA seqA mutant cells is decreased at 0 degrees C , but not at 30 degrees C, relative to the wild-type strain. A considerable increase in the permeability of membranes of the mutant cells for beta-galactosidase is demonstrated. The dnaA and seqA mutants are more sensitive to ethanol (an organic solvent) than wild-type bacteria, and the seqA strain and the double mutant dnaA seqA are very sensitive to deoxycholate (a detergent). We conclude that lesions in the genes dnaA and seqA result in alterations in cell membranes, such that the permeability and possibly also other properties of the membranes are significantly altered relative to wild-type bacteria.
Branchiogenic carcinoma is a rare condition and should not be diagnosed in the absence of the criteria laid down by Dr Hayes Martin. The authors describe a 65 year-old woman with a cystic mass on the side of the neck. The woman was admitted to the hospital for possible branchial cyst. The histopathological analysis showed a carcinoma developed on a branchial cyst. The authors stress the importance of careful and repeated clinical examinations, which exclude the possibility of a primary tumor of other localization.
Granular cell tumor is an unusual growth of probably neuroectodermal histogenesis, first reported by Abrikossoff in 1926 with the name of myoblastenmyoma. Authors described a case of a 54 year man with laryngeal seat of granular-cell myoblastoma. In this case Abrikossoff tumor was located in the right vocal chord. The tumor was treated successfully surgically by microlaryngoscopy. The etiology, clinical features and diagnostic difficulties are discussed.
The authors describe a rare case of hamartoma in the larynx of a 31 years old man. The egg sized tumor was situated in the left aryepiglottic fold filling the lower pharyngeal space. The unfortunate location, patient disdain as well as late diagnosis and proper management caused the histologically benign tumor to enlarge and block the laryngeal entrance that endangering life. After initial tracheotomy the tumor was successfully removed through the mouth.
The oop RNA is a short (77 nucleotides (nt)) transcript encoded by bacteriophage lambda which acts as an antisense RNA for lambda cII gene expression. Recently we demonstrated that oop RNA is specifically polyadenylated at its 3' end by poly(A) polymerase I (PAP I), the pcnB gene product. Here we demonstrate that the half life of oop RNA is 3 times longer in the pcnB mutant relative to the pcnB+ host, indicating that polyadenylation of this transcript causes its accelerated degradation. Although it was proposed that polyadenylation of RNAs in bacteria leads to their enhanced degradation, in most cases stabilization of these molecules was observed only when other mutations (pnp, rnb and rne) were present in the pcnB- strain. Therefore it seems that oop RNA may serve as a very useful model in further studies on molecular mechanisms of RNA polyadenylation and degradation in bacteria. Analysis of oop RNA and its degradation product isolated from Escherichia coli cells suggests that both polyadenylated and non-modified oop transcripts can act as antisense RNA.
We have shown that Escherichia coli pcnB mutants are lysogenized by bacteriophage lambda with lower efficiency as compared to the pcnB+ strains. Our genetic analysis revealed that expression of the lambda cII gene is decreased in the pcnB mutants. However, using various lacZ fusions we demonstrated that neither activities of pL and pR promoters nor transcription termination at tR1 were significantly impaired in the pcnB- host. On the other hand, we found that oop RNA, an antisense RNA for cII expression, is involved in this regulation. Primer protection experiments revealed that oop RNA was polyadenylated and that this polyadenylation was impaired in the pcnB mutant. We found that the oop RNA was more abundant in the pcnB mutant than in the pcnB+ strain. Furthermore, we showed that activity of the pO promoter was not stimulated in the pcnB mutant. Such findings indicated that degradation of oop RNA in the pcnB strain was slower because of inefficient polyadenylation, which could lead to more effective inhibition of cII expression by the antisense oop RNA, resulting in less efficient lysogenization of the host. The oop RNA was found previously to play a role in phage lambda development only under conditions of overproduction of this transcript. Here we demonstrate for the first time, the physiological function of oop RNA in lambda development, confirming that this short transcript plays an important role in the negative regulation of cII gene expression during lambda infection. Moreover, polyadenylation of oop RNA is one of very few known examples of specific RNA polyadenylation by PAP I in prokaryotic cells and its role in gene expression regulation.
Differential replication of various ColE1-type plasmids in stringent (relA+) and relaxed (relA-) strains of Escherichia coli starved for particular amino acids was reported previously. A role for the plasmid-encoded Rom protein in the stringent control of ColE1 replication has also been demonstrated. Here we have studied the efficiency of replication of five ColE1-type plasmids in E. coli relA+ and relA- strains starved for five amino acids to find the differential replication of each plasmid in cells starved for each amino acid. The efficiency of replication was found to be in positive correlation with the homology between nucleotide sequences of particular loops of RNA I or RNA II and anticodon loops of tRNA molecules corresponding to the kind of the amino acid deprived. Efficient plasmid DNA replication was observed under conditions for which we predicted (on the basis of theoretical calculations) relatively strong interactions between tRNA molecules, expected to occur in high concentrations in an uncharged from, and RNA I or RNA II. When the theoretical possibility of the tRNA-RNA I or tRNA-RNA II interactions was very small, the observed plasmid DNA replication was negligible. Replication of ColE1-like plasmids during the stringent response was observed only in the absence of a functional rom gene. We observed plasmid replication in the amino acid-starved pcnB relA double mutant. We propose a model for regulation of ColE1 replication in the amino acid-starved E. coli cells based on interactions between uncharged tRNA molecules and RNA I or RNA II. During starvation for different amino acids, different kinds of uncharged tRNA molecules appear in cells (they are much more abundant, however, in relA- mutants than in relA+ hosts) leading to various efficiencies of replication initiation. The Rom protein may modulate the effect of tRNA(s) by enhancing RNAI-RNA II, but not tRNA-RNA I and tRNA-RNA II, interactions.
It was previously demonstrated that the activity of bacteriophage lambda promoter pR is decreased in wild-type Escherichia coli cells starved for amino acids (during the stringent response). Since pR activity is necessary for the transcriptional activation of ori lambda, this leads to inhibition of the replication of plasmids derived from phage lambda. These results led to the proposal that the pR promoter susceptible to control by the stringent response. However, subsequent studies demonstrated that this promoter is activated by the host dnaA gene product and since the dnaA promoter was reported to be controlled by the stringent response, it is possible that the inhibition of pR activity in amino acid-starved cells is indirect, and results from the impairment of DnaA-mediated transcriptional activation. Here we present evidence that pR is negatively regulated by ppGpp, even when DnaA protein is provided in excess as well as in cells devoid of DnaA function. We have checked that the level of ppGpp is increased during prolonged (up to 4 h) starvation for isoleucine in relA+ cells but not in the relA- mutant. At the same time we observed inhibition of lambda plasmid replication during the stringent, but not relaxed, response, even when DnaA was overproduced. Finally, we found that the activity of a pR-lacZ fusion is inhibited after gratuitously induced overproduction of ppGpp in unstarved cells, irrespective of the status of the dnaA gene product. We conclude that the activity of the pR promoter is inhibited directly by ppGpp.
Otherwise isogenic Escherichia coli CP78 (relA+) and CP79 (relA-) strains are commonly used in studies on the stringent control, the bacterial response to amino acid starvation. We found that these strains are lysogenic for a phage which is spontaneously induced with a low frequency, producing virions able to infect other E. coli strains. Genetic studies, restriction analysis of the phage DNA genome, and electron microscopy revealed that this phage is very similar to, but not identical with, bacteriophage lambda. We called the newly isolated phage lambdaW, and found that most of CP78/CP79 ancestor strains are lysogenic for this phage.
Amino acid starvation of Escherichia coli relA mutants was previously proposed as a method for efficient amplification of plasmids bearing origin of replication derived from ColE1-type plasmids and bacteriophage lambda. Here we demonstrate that plasmids derived from pSC101 replicon can be amplified in E. col relA+ and relA- strains during amino acid limitation but not during amino acid starvation. The amplification efficiency is dependent on temperature (37 degrees C was found to be the optimal temperature). Under optimal conditions, up to 13-fold amplification of a pSC101-derived plasmid may be achieved.
It was demonstrated previously that replication of plasmids derived from bacteriophage lambda (so-called lambda plasmids) is inhibited in wild-type Escherichia coli cells starved for isoleucine and arginine whereas it proceeds under the same conditions in relA mutants. Since replication of other replicons during the stringent or relaxed response depends on the nature of the deprived amino acid, we investigated replication of lambda plasmids in E. coli relA+ and relA- strains starved for different amino acids. We found that replication of lambda plasmids is generally inhibited during the stringent, but not relaxed, response. Differences between cells starved for different amino acids, although reproducible, were not dramatic. Amino acid starvation was previously proposed as a method for amplification of lambda plasmid DNA in vivo. We found that during amino acid limitation lambda plasmids replicate more extensively in the relA mutants than during amino acid starvation. The efficiency of plasmid DNA amplification was found to be dependent on the kind of limited amino acid; in relA- bacteria limited for leucine we observed about 10-fold plasmid amplification. Some lambda plasmid replication was also found under these conditions in the relA+ host. The mechanism of the stringent control of lambda plasmid DNA replication has already been proposed. Here the possible mechanism of the regulation of lambda plasmid replication during amino acid limitation is presented.