Trends in designing microbial silage quality by biotechnological methods using lactic acid bacteria inoculants: a minireview.

Ensiling is one of the best known method to preserve fodder. The forage before ensiling intended for silages usually contains a low number of lactic acid bacteria (LAB), so it is necessary to apply starter cultures of selected strains. Traditionally, LAB starter cultures were applied to lower the pH by producing lactic acid and to inhibit the growth of undesirable epiphytic microorganisms by competing for nutrients. Nowadays, LAB inoculants have become an effective tool for creating microbial quality of silages by selecting species with extraordinary features. Epiphytic microflora characteristic of plant material used for the production of silages and the sources of undesirable microflora in the ensiling process are discussed. This review focuses on the most frequently studied issues related to the microbial silage quality and the recent trends in increasing the quality by LAB inoculants, with respect to recent directions for selecting types of modern LAB for inoculation. Among them, the main trends described were prevention of the growth of filamentous fungi and detoxification of mycotoxins by LAB inoculants, inhibition of yeast growth by LAB present in preparations and limiting the development of pathogenic bacterial microflora through controlled fermentation with the participation of LAB and the presence of their metabolites.

Lipofuscin, homocysteine and tissue polypeptide specific antigen in gestational hypertension.

OBJECTIVE: The aim of this study were to assess the levels of lipofuscin (parameter of oxidative stress), homocysteine (as a marker of vascular injury) and tissue specific antigen - TPS - (as a marker of cell proliferation) in relation to arterial pressure of pregnant woman. STUDY DESIGN: Healthy pregnant women (n=18), women with mild 140/90=< RR<160/100 (n=19), and severe 160/100=

The size of selected human skull foramina in relation to skull capacity.

An anatomical study was undertaken in order to investigate whether the sizes of selected human skull foramina with significant venous compartments correlated significantly with skull capacity. A total of 100 macerated human skulls were examined to determine the diameter of the foramina and the skull capacity. Measurements of the surface area of the foramina were made using a computerised digital analysis system. Only the size of the hypoglossal canal and jugular foramen were found to correlate significantly with the capacity of the skull. This correlation, together with the considerable size of the hypoglossal canal, indicated its important role in the venous drainage of the brain. There was considerable centralisation of venous outflow from the brain, with 60% of the area of all venous foramina of the skull occupied by jugular foramina. Asymmetry between the right and left jugular foramina was identified, with an average ratio of 1.6 (ranging between 1 and 3.47). In the case of right-sided domination the correlation between the skull capacity and the size of both jugular foramina was negative (the larger the skull cavity, the less the asymmetry), while in the case of left-sided domination the correlation was positive. Perhaps the left-sided domination is less advantageous for the haemodynamics of blood outflow, as the left brachiocephalic vein is longer and is often compressed by the sternum and aortic arch.

Polyadenylation of oop RNA in the regulation of bacteriophage lambda development.

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.

Rapid degradation of polyadenylated oop RNA.

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.

Inhibition of spontaneous induction of lambdoid prophages in Escherichia coli cultures: simple procedures with possible biotechnological applications.

BACKGROUND: Infections of bacterial cultures by bacteriophages are serious problems in biotechnological laboratories. Apart from such infections, prophage induction in the host cells may also be dangerous. Escherichia coli is a commonly used host in biotechnological production, and many laboratory strains of this bacterium harbour lambdoid prophages. These prophages may be induced under certain conditions leading to phage lytic development. This is fatal for further cultivations as relatively low, though still significant, numbers of phages may be overlooked. Thus, subsequent cultures of non-lysogenic strains may be infected and destroyed by such phage. RESULTS: Here we report that slow growth of bacteria decreases deleterious effects of spontaneous lambdoid prophage induction. Moreover, replacement of glucose with glycerol in a medium stimulates lysogenic development of the phage after infection of E. coli cells. A plasmid was constructed overexpressing the phage 434 cI gene, coding for the repressor of phage promoters which are necessary for lytic development. Overproduction of the cI repressor abolished spontaneous induction of the lambda(imm434) prophage. CONCLUSIONS: Simple procedures that alleviate problems with spontaneous induction of lambdoid prophage and subsequent infection of E. coli strains by these phages are described. Low bacterial growth rate, replacement of glucose with glycerol in a medium and overproduction of the cI repressor minimise the risk of prophage induction during cultivation of lysogenic bacteria and subsequent infection of other bacterial strains.

Replication and amplification of lambda plasmids in Escherichia coli during amino acid starvation and limitation.

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.

Inhibitory effect of ethanol on the 5-hydroxytryptamine-induced Bezold-Jarisch reflex--involvement of peripheral 5-HT3 receptors.

The influence of ethanol (0.5, 1.0 and 2.0 g/kg i.p.) on the Bezold-Jarisch reflex in urethane-anaesthetized rats was studied. 5-Hydroxytryptamine (serotonin; 5-HT; 1, 3, 10 and 30 micrograms/kg i.v.) and capsaicin (1, 3 and 10 micrograms/kg i.v.) reflexly decreased heart rate in a dose-dependent manner. The 5-HT3 receptor antagonist ondansetron 10 micrograms/kg i.v. abolished the 5-HT- but not the capsaicin-stimulated bradycardia, indicating that 5-HT and capsaicin acted via different trigger mechanisms (5-HT3 receptor-dependent and -independent, respectively). Ethanol at 1.0 and 2.0 g/kg i.p. inhibited in a dose-dependent manner (by 20-45%) the 5-HT- but not the capsaicin-stimulated decrease in heart rate. Our results demonstrate that the inhibitory effect of ethanol on the 5-HT3 receptor-mediated Bezold-Jarisch reflex may be related to the direct effect of ethanol on 5-HT3 receptors on sensory vagal nerves in the heart.

Amplification of pSC101 replicons in Escherichia coli during amino acid limitation.

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.

Production and purification of SV40 major capsid protein (VP1) in Escherichia coli strains deficient for the GroELS chaperone machine.

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.

Biochemical and genetic analysis of lambdaW, the newly isolated lambdoid phage.

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.

Differential amplification efficiency of pMB1 and p15A (ColE1-type) replicons in Escherichia coli stringent and relaxed strains starved for particular amino acids.

It was demonstrated previously that ColE1-type plasmids, the most commonly used vectors in molecular cloning, can be amplified in amino acid-starved relA mutants of Escherichia coli. Subsequent studies demonstrated that replication of at least some plasmids during amino acid starvation depends not only on the host relA allele but also on temperature and on the nature of deprived amino acid. Therefore, we investigated efficiency of amplification of two types of ColE1 plasmids (pMB1- and p15A-derived replicons) in E. coli relA+ and relA- hosts starved for different amino acids at 30 degrees C, 37 degrees C and 43 degrees C. We found differential amplification efficiency of plasmids pBR328 (pMB1-derived replicon) and pACYC184 (p15A-derived replicon) in the relA mutant during starvation for particular amino acids. Although amplification of pBR328 was negligible in the relA+ host, significant increase in pACYC184 content was observed in this strain starved for some (but not all) amino acids. The amplification efficiency of pBR328 and pACYC184 was found to be dependent on temperature. These results indicate that for maximal amplification of particular plasmid appropriate amino acid starvation and optimal temperature should be chosen. Our findings are in agreement with recently proposed model of the regulation of ColE1-type plasmid replication in amino acid-starved E. coli cells.

Evaluating critical thinking skills of baccalaureate nursing students.

This study evaluates the critical thinking skills of students enrolled in a baccalaureate nursing program, using the WGCTA, for the classes of 1993 through 1996. Scores were obtained at entry and at end of junior and senior years. The mean entry WGCTA score was 56 for all four classes; however, the 1995 and 1996 classes had significantly higher scores than the class of 1994. Critical thinking scores were higher at entry for older students and students who had completed another education degree; however, critical thinking scores were lower for students who had previous nursing experience. After adapting for age, previous degree, and nursing experience, no significant differences in the WGCTA scores from entry to end of junior and senior years emerged for the classes of 1993, 1994, 1995. Critical thinking skills have become the hallmark of education. The National Education Goal Panel has advocated for an increase in the ability to think critically, communicate effectively and solve problems (Banta, 1993). In turn, the nursing profession has incorporated these goals of higher education into its educational programs. The National League for Nursing (NLN) includes the measurement of critical thinking as a required outcome in the evaluation and accreditation of baccalaureate and higher degree programs in nursing. This critical thinking outcome must reflect the student's skill in analysis, reasoning, research, or decision making as these skills relate to the nursing discipline (National League for Nursing, 1992). To meet the NLN's critical thinking outcome criterion, nursing programs must have a method of evaluating this skill. Many programs use the Watson-Glaser Critical Thinking Appraisal (WGCTA), which is a standardized instrument. The College of Nursing at the University of Arkansas for Medical Sciences (UAMS) adopted this instrument to evaluate the critical thinking skills of students in the baccalaureate nursing program.

Management education. Needs of nurse administrators in long-term care.

Nurse administrators in long-term care experience relatively short tenure in the management role. Since the majority of nurse administrators in long-term care facilities have initial nursing preparation at the diploma or associate degree level, they do not receive educational preparation in leadership and management in their nursing education programs. There is a need for management education of nurse administrators in rural long-term care facilities, as perceived by chief executive officers and nurse administrators.

Addressing the National League for Nursing critical-thinking outcome.

The National League for Nursing outcome-oriented accreditation process challenges nursing faculty to think about teaching and evaluating critical thinking. In a survey of schools of nursing, the authors found that programs are using standardized measures and individualized assessments to address the criterion. Their greatest difficulty involves decisions about measuring critical thinking. School administrators identified a variety of approaches effective for helping faculty. The authors provide insight and ideas for nursing faculty involved with critical thinking in the curricula.

AIDS: family physicians' attitudes and experiences.

A study was developed to examine the current experiences and opinions of a national sample of family physicians with regard to acquired immunodeficiency syndrome (AIDS). The survey response rate was 72.5% (757 questionnaires were returned out of a sample of 1044). Approximately 47% of respondents have cared for an HIV-infected patients. This percentage varied from a low of 31.4% in the Midwest to as high as 56.1% on the East Coast. Thirty-two percent of family physicians practicing in communities of fewer than 2500 have dealt with this illness, while 60% of those in communities of greater than 100,000 have done so. Seventy-seven percent of respondents are willing to provide care to HIV-infected individuals; 62.9% believe that physicians have a right to refuse to care for a patient because he or she is infected with the AIDS virus. Forty percent believe that they would lose patients if it were known that they were caring for an AIDS patient in their office. Finally, the vast majority of those surveyed favor required partner notification and would inform the sexual partner of an HIV-positive patient if the patient refused to do so.

Interactions of minoxidil with vasoconstrictive agents in isolated rat tail artery.

The role of minoxidil in the inhibition of norepinephrine, serotonin, angiotensin and potassium chloride-induced vasocontractions was investigated. Isolated rat tail artery was used as an experimental model. It was found that the examined drug reduced serotonin angiotensin and norepinephrine-evoked rises in perfusion pressure, being the most potent inhibitory agent towards serotonin. Minoxidil failed to inhibit the response of isolated vessels to potassium chloride. The minoxidil may be involved in the inhibition of serotonergic (5-HT2) receptors.

[A incidence of cancer in the lateral side of the neck in a 65-year-old woman]. / Przypadek raka w torbieli bocznej szyi u 65-letniej kobiety.

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.

[A case of cancer transformation of planocellular papilloma of the lip into squamous cell carcinoma]. / Przypadek przemiany nowotworowej brodawczaka plaskonablonkowego wargi dolnej w raka plaskonablonkowego kolczystokomórkowego.

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.

[Giant tonsillolith simulating peritonsillar abscess]. / Olbrzymi kamien migdalka imitujacy ropien okolomigdalkowy.

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.