bluuebunny/crossref_metadata_2025 huggingface dataset:
L-Serine deaminase activity is induced by exposure of Escherichia coli K-12 to DNA-damaging agents
Authors: Newman E B , Ahmad D , Walker C
Published: June 2021

The synthesis of L-serine deaminase in Escherichia coli K-12 was induced after exposure of cells to a variety of DNA-damaging agents, including UV irradiation, nalidixic acid, and mitomycin C. Synthesis was also induced during growth at high temperature. A mutant constitutive for SOS functions showed an elevated level of L-serine deaminase activity. The response to DNA-damaging agents thus may be mediated via the SOS system.
Purification and Mn2+ activation of Rhodospirillum rubrum nitrogenase activating enzyme
Authors: Gotto J W , Yoch D C
Published: June 2021

The Fe protein activating enzyme for Rhodospirillum rubrum nitrogenase was purified to approximately 90% homogeneity, using DE52-cellulose chromatography and sucrose density gradient centrifugation. Activating enzyme consists of a single polypeptide of molecular weight approximately 24,000. ATP was required for catalytic activity, but was relatively ineffective in the absence of Mg2+. When the concentration of MgATP2- was held in excess, there was an additional requirement for a free divalent metal ion (Mn2+) for enzyme activity. Kinetic experiments showed that the presence of Mg2+ influenced the apparent binding of Mn2+ by the enzyme, resulting in a lowering of the concentration of Mn2+ required to give half-maximum activity (K alpha) as the free Mg2+ concentration was increased. A low concentration of Mn2+ had a sparing effect on the requirement for free Mg2+. There is apparently a single metal-binding site on activating enzyme which preferentially binds Mn2+ as a positive effector, and free Mg2+ can compete for this site.
Isolation, purification, and partial characterization of type V-A hemagglutinin from Escherichia coli GV-12, O1:H-
Authors: Sheladia V L , Chambers J P , Guevara J , Evans D J
Published: June 2021

A hemagglutinin which specifically agglutinates human type A erythrocytes (mannose resistant) was isolated from the growth medium of cultures of Escherichia coli GV-12, serotype O1:H-, and purified by chromatography on Bio-Gel A-1.5 and DEAE-Sephadex A-25. The purity of the hemagglutinin was established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoelectrophoresis. N-terminus analysis indicated that only asparagine resides on the amino terminus. The native hemagglutinin is an aggregate exhibiting a sedimentation coefficient of 9.25, which corresponds to a molecular weight of approximately 200,000. The monomeric molecular weight was found to be approximately 16,300. Amino acid analysis indicated that the hemagglutinin consists of 131 residues, corresponding to a molecular weight of 13,400.
Enhancement of pneumococcal transfection by protamine sulfate
Authors: Goscin L P , Guild W R
Published: June 2021

Protamine sulfate enhanced transfection of Streptococcus pneumoniae by DNA of omega 3 phage by factors as large as 10(5)-fold, provided it was present at the time the cells were added to the DNA. For DNA concentrations well below 1 microgram/ml, the optimum amount of protamine sulfate was near 1 microgram/ml of cells. Higher DNA concentrations required more protamine for maximum effect, and in all cases transfection fell when protamine was in excess. Transformation was not enhanced by low protamine levels and was inhibited by higher levels. A recipient strain with low but finite endonuclease activity and normal transformability showed higher transfection than did the wild type at low DNA concentrations but less than did the wild type at high DNA concentrations. Protamine sulfate enhanced its transfection at low, but not high, DNA concentrations. The behavior of this strain and the enhancement of transfection by protamine sulfate of wild-type cells were each consistent with less cutting of the donor DNA at the cell surface, which is part of the normal entry process in naturally competent gram-positive bacteria. Less cutting would lead to entry of fewer but longer strands that would be more efficient in reconstruction of the 33-megadalton phage replicon. We suggest that in this system protamine enhances transfection by inhibition of the surface nuclease action that is part of the normal entry process.
The incompatibility product of IncFII R plasmid NR1 controls gene expression in the plasmid replication region
Authors: Easton A M , Rownd R H
Published: June 2021

The incompatibility properties of IncFII R plasmid NR1 were compared with those of two of its copy number mutants, pRR12 and pRR21. pRR12 produced an altered incompatibility product and also had an altered incompatibility target site. The target site appeared to be located within the incompatibility gene, which is located more than 1,200 base pairs from the plasmid origin of replication. The incompatibility properties of pRR21 were indistinguishable from those of NR1. Lambda phages have been constructed which contain the incompatibility region of NR1 or of one of its copy mutants fused to the lacZ gene. In lysogens constructed with these phages, beta-galactosidase was produced under the control of a promoter located within the plasmid incompatibility region. Lysogens containing prophages with the incompatibility regions from pRR12 and pRR21 produced higher levels of beta-galactosidase than did lysogens containing prophages with the incompatibility region from the wild-type NR1. The introduction into these inc-lac lysogens of pBR322 plasmids carrying the incompatibility regions of the wild-type or mutant plasmids resulted in decreased levels of beta-galactosidase production. For a given lysogen, the decrease was greater when the pBR322 derivative expressed a stronger incompatibility toward the plasmid from which the fragment in the prophage was derived. This suggested that the incompatibility product acts on its target to repress gene expression in the plasmid replication region.
Generation and release of DNA-binding vesicles by Haemophilus influenzae during induction and loss of competence
Authors: Deich R A , Hoyer L C
Published: June 2021

Genetic transformation of bacterial cells required the induction of a state of competence to bind and absorb free DNA molecules. Induction of competence in Haemophilus influenzae was accompanied by the generation on the cell surface of membrane extensions ("blebs") 80 to 100 nm in diameter. When competent cells were returned to normal growth conditions, they shed these structures as free vesicles with a concomitant loss of cellular DNA-binding activity. Purified vesicle preparations retained the ability to bind double-stranded DNA in a nuclease-resistant, salt-stable form. Binding was specific for DNA molecules containing the 11-base pair Haemophilus uptake sequence, required Na+ and divalent cations (Mg2+, Ca2+, or Mn2+), and was inhibited by the presence of EDTA or high concentrations of salt (greater than 0.5 M NaCl). Binding was not stimulated by nucleotide triphosphates and was insensitive to the uncoupling agents dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone. Vesicles contained the major Haemophilus outer membrane proteins and were enriched in several minor proteins.
Asparagine-linked carbohydrate does not determine the cellular location of yeast vacuolar nonspecific alkaline phosphatase
Authors: Clark D W , Tkacz J S , Lampen J O
Published: June 2021

The nonspecific alkaline phosphatase of Saccharomyces sp. strain 1710 has been shown by phosphatase cytochemistry to be exclusively located in the vacuole, para-Nitrophenyl phosphate-specific alkaline phosphatase is not detected by this procedure because the activity of this enzyme is sensitive to the fixative agent, glutaraldehyde. To determine whether the oligosaccharide of nonspecific alkaline phosphatase is necessary to transport the enzyme into the vacuole, protoplasts were derepressed in the absence or in the presence of tunicamycin, an antibiotic which interferes with the glycosylation of asparagine residues in proteins. The location of the enzyme in the tunicamycin-treated protoplasts, as determined by electron microscopy and subcellular fractionation, was identical to its location in control protoplasts. In addition, carbohydrate-free alkaline phosphatase was found in vacuoles from tunicamycin-treated protoplasts. Our findings indicate that the asparagine-linked carbohydrate moiety does not determine the cellular location of the enzyme.
Structural characteristics of tetanolysin and its binding to lipid vesicles
Authors: Rottem S , Cole R M , Habig W H , Barile M F , Hardegree M C
Published: June 2021

Tetanolysin binding to lipid vesicles was found to depend on the molar ratio of cholesterol to phospholipid, being low in vesicles containing up to 20 mol% cholesterol and high in vesicles containing more than 33 mol%. High concentrations of purified tetanolysin preparations formed arc- and ring-shaped structures. The structures were not readily detectable in diluted preparations unless incubated with lipid vesicles containing high molar ratios of cholesterol to phospholipid. It is suggested that the toxin is concentrated on the vesicles to local concentrations high enough to form the arcs and rings.
Gene ompR and regulation of microcin 17 and colicin e2 syntheses
Authors: Hernández-Chico C , Herrero M , Rejas M , San Millán J L , Moreno F
Published: June 2021

The production of microcin 17 is controlled by plasmid pRYC17. Chromosomal mutants unable to produce a normal amount of microcin were isolated in Escherichia coli. One of the mutations maps in the ompR locus, indicating that an active OmpR product is required for the synthesis of microcin 17. The same conclusion was obtained for the synthesis of colicin E2. Therefore, two new functions of the regulatory gene ompR have been revealed.
Bacteriophage P22 as a vector for Mu mutagenesis in Salmonella typhimurium: isolation of nad-lac and pnc-lac gene fusions
Authors: Holley E A , Foster J W
Published: June 2021

Salmonella phage P22 was utilized as a vector for phage Mu cts d1(Apr lac) mutagenesis in Salmonella typhimurium. Efficient transposition of phage Mu d1 and the construction of gene fusions were readily accomplished with this procedure. Mutants blocked in the biosynthesis of NAD+ and in pyridine nucleotide cycle metabolism were isolated by this method, resulting in nadB-lac, nadC-lac, and pncB-lac gene fusions.
Nucleoside salvage pathway for NAD biosynthesis in Salmonella typhimurium
Authors: Liu G , Foster J , Manlapaz-Ramos P , Olivera B M
Published: June 2021

A previously undescribed nucleoside salvage pathway for NAD biosynthesis is defined in Salmonella typhimurium. Since neither nicotinamide nor nicotinic acid is an intermediate in this pathway, this second pyridine nucleotide salvage pathway is distinct from the classical Preiss-Handler pathway. The evidence indicates that the pathway is from nicotinamide ribonucleoside to nicotinamide mononucleotide (NMN) and then to nicotinic acid mononucleotide, followed by nicotinic acid adenine dinucleotide and NAD. The utilization of exogenous NMN for NAD biosynthesis has been reexamined, and in vivo evidence is provided that the intact NMN molecule traverses the membrane.
Synthesis of acid-soluble spore proteins by Bacillus subtilis
Authors: Leventhal J M , Chambliss G H
Published: June 2021

The major acid-soluble spore proteins (ASSPs) of Bacillus subtilis were detected by immunoprecipitation of radioactively labeled in vitro- and in vivo-synthesized proteins. ASSP synthesis in vivo began 2 h after the initiation of sporulation (t2) and reached its maximum rate at t7. This corresponded to the time of synthesis of mRNA that stimulated the maximum rate of ASSP synthesis in vitro. Under the set of conditions used in these experiments, protease synthesis began near t0, alkaline phosphatase synthesis began at about t2, and refractile spores were first observed between t7 and t8. In vivo- and in vitro-synthesized ASSPs comigrated in sodium dodecyl sulfate-polyacrylamide gels. Their molecular weights were 4,600 (alpha and beta) and 11,000 (gamma). The average half-life of the ASSP messages was 11 min when either rifampin (10 micrograms/ml) or actinomycin D (1 microgram/ml) was used to inhibit RNA synthesis.
Cloning and expression of the beta-D-phosphogalactoside galactohydrolase gene of Lactobacillus casei in Escherichia coli K-12
Authors: Lee L J , Hansen J B , Jagusztyn-Krynicka E K , Chassy B M
Published: June 2021

Lactose metabolism in Lactobacillus casei 64H is associated with the presence of plasmid pLZ64. This plasmid determines both phosphoenolpyruvate-dependent phosphotransferase uptake of lactose and beta-D-phosphogalactoside galactohydrolase. A shotgun clone bank of chimeric plasmids containing restriction enzyme digest fragments of pLZ64 DNA was constructed in Escherichia coli K-12. One clone contained the gene coding for beta-D-phosphogalactoside galactohydrolase on a 7.9-kilobase PstI fragment cloned into the vector pBR322 in E. coli strain chi 1849. The beta-D-phosphogalactoside galactohydrolase enzyme isolated from E. coli showed no difference from that isolated from L. casei, and specific activity of beta-D-phosphogalactoside galactohydrolase was stimulated 1.8-fold in E. coli by growth in media containing beta-galactosides. A restriction map of the recombinant plasmid was compiled, and with that information, a series of subclones was constructed. From an analysis of the proteins produced by minicells prepared from transformant E. coli cells containing each of the recombinant subclone plasmids, it was found that the gene for the 56-kilodalton beta-D-phosphogalactoside galactohydrolase was transcribed from an L. casei-derived promoter. The gene for a second protein product (43 kilodaltons) was transcribed in the opposite direction, presumably under the control of a promoter in pBR322. The relationship of this second product to the lactose metabolism genes of L. casei is at present unknown.
Genetic analysis of acrA and lir mutations of Escherichia coli
Authors: Henson J M , Walker J R
Published: June 2021

An analysis of acrA (acriflavine- and methylene blue-sensitive) and lir (lincomycin- and erythromycin-sensitive) mutants of Escherichia coli indicated that these mutations are probably within the same gene.
Chromosomal replication origins (oriC) of Enterobacter aerogenes and Klebsiella pneumoniae are functional in Escherichia coli
Authors: Harding N E , Cleary J M , Smith D W , Michon J J , Brusilow W S , Zyskind J W
Published: June 2021

The chromosomal DNA replication origins (oriC) from two members of the family Enterobacteriaceae, Enterobacter aerogenes and Klebsiella pneumoniae, have been isolated as functional replication origins in Escherichia coli. The origins in the SalI restriction fragments of 17.5 and 10.2 kilobase pairs, cloned from E. aerogenes and K. pneumoniae, respectively, were found to be between the asnA and uncB genes, as are the origins of the E. coli and Salmonella typhimurium chromosomes. Plasmids containing oriC from E aerogenes, K. pneumoniae, and S. typhimurium replicate in the E. coli cell-free enzyme system (Fuller, et al., Proc. Natl. Acad. Sci. U.S.A. 78:7370--7374, 1981), and this replication is dependent on dnaA protein activity. These SalI fragments from E. aerogenes and K. pneumoniae carry a region which is lethal to E. coli when many copies are present. We show that this region is also carried on the E. coli 9.0-kilobase-pair EcoRI restriction fragment containing oriC. The F0 genes of the atp or unc operon, when linked to the unc operon promoter, are apparently responsible for the lethality.
Comparison of kinetic and end-point diffusion methods for quantitating human serum immunoglobulins
Authors: Taylor R N , Fulford K M , Huong A Y
Published: June 2021

Proficiency testing results were used to compare the kinetic and end-point versions of the single radial immunodiffusion method for quantitating human serum immunoglobulins. Statistical analysis of the results indicated that the results were not normally distributed but that the log normal distribution gives the best fit of any of the well-known frequency distributions. Consequently, statistical analysis of immunoglobulin results must be log transformed before parametric statistical tests can be appropriately applied. In general, there were no significant differences in level, precision, or interlaboratory comparability for these two methods. However, levels were different for participants using Hyland reagents, and better interlaboratory comparability was achieved by the end-point assay for immunoglobulin M. There were no significant differences in reported levels when compared by manufacturer within the same method.
Possible use of frequency-pulse-modulated electron capture gas-liquid chromatography to identify septic and aseptic causes of pleural effusions
Authors: Brooks J B , Craven R B , Schlossberg D , Alley C C , Pitts F M
Published: June 2021

Frequency-pulse-modulated electron capture gas-liquid chromatography was used in conjunction with appropriate derivatization procedures to obtain chromatograms from extracts of pleural effusions. These chromatograms were used to rapidly classify the various types of pleural effusions. With this method we have been able to distinguish among a limited number of effusions caused by congestive heart failure, Mycobacterium tuberculosis, and some other types of bacterial empyemas and pleural effusions.
Detection of antibody to bovine syncytial virus and respiratory syncytial virus in bovine fetal serum
Authors: Gould E A , Allan G M , Logan E F , McFerran J B
Published: June 2021

Batches of commercial fetal bovine serum, described by the suppliers as antibody-free, all contained antibody to bovine syncytial virus (BSV) when tested by indirect immunofluorescence. Antibody to bovine respiratory syncytial virus (RSV) was not detected in these sera. Twenty-four percent of individual fetal bovine sera contained antibody to BSV, and 14% contained antibody to RSV when tested by indirect immunofluorescence. BSV antibody titers in fetal sera from dams with high BSV antibody levels were variable but always higher than RSV antibody titers. Radial immunodiffusion studies with BSV-positive sera revealed the presence of immunoglobulin M (IgM), IgG, and IgA, but the quantity of these immunoglobulins was not directly related to the BSV antibody titers. The evidence suggests that the antibody present in fetal sera arose as the result of infection rather than from maternal transfer across the placenta.
Comparison of three blood culture media with tryptic soy broth
Authors: Hall M M , Ilstrup D M , Washington J A
Published: June 2021

Four consecutive studies comparing commercially prepared bottles that contained brain heart infusion, brucella (vented and unvented), and Trypticase soy broths with Tryptic soy broth failed to demonstrate significant differences in rates of isolation of organisms from blood. Statistically significant differences between bottles were limited to the average times required to detect growth of viridans streptococci in one study and of all organisms in another.
Detection of Legionnaires disease bacteria by direct immunofluorescent staining
Authors: Cherry W B , Pittman B , Harris P P , Hebert G A , Thomason B M , Thacker L , Weaver R E
Published: June 2021

Antisera and fluorescein isothiocyanate conjugates prepared for five strains of the Legionnaires bacteria were tested in both homologous and heterologous staining reactions with 10 isolates of the organism from patients in seven geographic areas. The strains were related but not identical as judged by the results of direct immunofluorescence staining. The conjugates were successfully used to detect Legionnaires disease bacteria in Formalin-fixed lung scrapings, in histological sections, and in fresh lung tissue obtained at biopsy or autopsy. In addition, the labeled antibodies are valuable for staining suspected cultures of the bacterium and for searching for the source of these organisms in soil, water, and other environmental niches. The reagents are highly specific for detecting the Legionnaires organism in clinical specimens.
Assessment of availability and efficacy of commercial Salmonella grouping antisera
Authors: Evins G M , Linne L L , Colvin H M
Published: June 2021

Salmonella somatic antisera for groups A to E were purchased from four commercial producers directly by the Center for Disease Control (CDC) and indirectly through two hospitals. CDC specifications and methods were used to evaluate antisera shipped directly to CDC. To assess the performance of the products under simulated user conditions, we used the commercial antisera purchased indirectly through the hospitals to group coded cultures. Of the 23 antisera ordered by CDC and the hospitals, the CDC received all 23, a large medical complex received 20, and a private hospital received 9. Similar results were obtained with producer and CDC test methods. Forty-five different lots of antisera were evaluated, of which 20% did not meet CDC specifications. The CDC specifications and latest revisions are discussed.
Species identification of coagulase-negative staphylococci from urinary tract isolates
Authors: John J F , Gramling P K , O'Dell N M
Published: June 2021

A new scheme for identification of coagulase-negative staphylococci was applied to 138 consecutive urinary isolates of coagulase-negative staphylococci. The most common species were Staphylococcus epidermidis (53%), S. hominis (12%), and S. haemolyticus (10%). S. saprophyticus comprised only 5%. The disk method for antibiotic susceptibility for all species grouped together disclosed resistance most commonly to penicillin (35%), tetracycline (33%), methicillin (27%), and sulfonamide (24%). This pattern was also seen specifically with S. epidermidis. Further studies are needed to determine the incidence of species-specific antibiotic resistance and species-specific infection by site. This may be of particular interest in those patients with nosocomial infections due to coagulase-negative staphylococci.
Utilization of a specific in vitro lymphocyte immunostimulation assay as an aid in detection of brucella-infected cattle not detected by serological tests
Authors: Kaneene J M , Johnson D W , Anderson R K , Muscoplat C C
Published: June 2021

Studies using the in vitro lymphocyte stimulation test (LST) were conducted with cattle in a dairy herd with a high percentage of reactors to several serological tests for brucellosis. Lymphocytes were prepared from peripheral bovine blood by the Ficoll-diatrizoate technique. Lymphocytes were cultured using microtitration culture plates. Brucella abortus soluble antigen, at a concentration of 4.4 microgram/culture, was added to the appropriate wells of microtitration culture plates and incubated for 6 days. The lymphocyte stimulation responses were measured by assaying for [3H]thymidine incorporation into DNA. Seroagglutination tests were conducted simultaneously with the LST, and tissues were collected after slaughter of the cattle for bacteriological culture to isolate B. abortus. All 21 animals studied were serologically negative for anti-brucella antibodies. Two of the 21 animals were classified as infected with Brucella by the LST, and B. abortus biotype 1 was isolated from tissues of these same two animals. The LST exhibited significant sensitivity and specificity in this study, and more observations of this nature might strengthen the application of this assay as an aid in the diagnosis of brucellosis.
Complement fixation antibody test for human nocardiosis
Authors: Shainhouse J Z , Pier A C , Stevens D A
Published: June 2021

Complement-fixing antibody was detected in 13 of 16 patients with histological and/or culture evidence of infection with Nocardia species. The antigen used was a filtrate of soluble substances secreted into liquid growth medium by cultures of N. asteroides. Apparent false positives reactions were found in three of three patients with leprosy and two of five patients with tuberculosis--results similar to some previously reported methods. N. asteroides and mycobacteria share antigens. Only the false positives with tuberculosis are considered a diagnostic problem. No reactions were obtained with sera from 26 patients with other infections and 41 unifected individuals. Whereas previous nocardia serodiagnostic methods have a sensitivity of approximately 50%, our overall sensitivity (81%) compares favorably and included 9 of 11 positive tests in immunocompromised nocardiosis patients (a source of false negative reactions with previous methods).
Method for evaluating broth culture media: application to Haemophilus
Authors: Brinkley A W , Huber T W
Published: June 2021

A method was devised to test the growth-promoting ability of a broth medium. The "dilute to extinction" method determines the inoculum required to develop heavy turbidity in a broth with overnight incubation. A statistical method using Poisson distribution was used to show that a single Haemophilus cell can develop heavy turbidity in an optimal broth. The dilute to extinction method was used to evaluate the shelf life of stored media, to titrate the growth factor requirements of Haemophilus, and to evaluate the use of purified hemin and nicotinamide adenine dinucleotide in a broth medium for the growth of Haemophilus. Of the media tested, the most suitable formulation was Mueller-Hinton broth supplemented with 10 microgram of hemin and 10 microgram of nicotinamide adenine dinucleotide per ml. The dilute to extinction method appears to be especially useful in the development of broth media for fastidious organisms. The method could also be used to assure the quality of other broth media which are required to support the growth of small inocula in the clinical or research laboratory.
Commercial cryptococcal latex kit: clinical evaluation in a medical center hospital
Authors: Prevost E , Newell R
Published: June 2021

A commercial latex kit for the detection of cryptococcal antigen (LCAT) was used in a medical center hospital to test cerebrospinal fluid (CSF) and serum specimens from patients suspected of having cryptococcal infections. The LCAT was also performed on 8 CSF and 2 serum specimens from other mycotic infections and on 50 serum specimens from healthy controls. Of a total of 561 specimens (489 CSF and 72 sera) from 426 patients, 78 (13.9%) specimens were LCAT positive; these came from 12 patients with culturally proven cryptococcosis. Eleven of these 12 patients were diagnosed as having disseminated cryptococcosis (9 with meningitis). Fourteen other patients, all with positive cultures for Cryptococcus neoformans but nevative LCATs on sera or CSF, were found not to have disseminated infections. All CSF and sera from other mycotic infections and all 50 control sera were negative. No false positive or flase negative tests were encountered. It was concluded that the commercial kit is useful for diagnosis and prognosis of disseminated cryptococcosis, but not as useful for infections such as localized pulmonary or cutaneous cryptococcosis.
Broadly reacting precipitating and agglutinating antigen of leptospirae
Authors: Myers D M , Coltorti E A
Published: June 2021

A saprophytic Leptospira biflexa strain of equine origin was found which cross-reacts with immune rabbit antisera to 14 pathogenic Leptospira interrogans serotypes. Sera from goats experimentally inoculated with the saprophyte showed multiple low-level cross-agglutination reactions against a battery of live L. interrogans serotypes. Sonically treated and saline-extracted suspensions of the L. biflexa strain and serotypes canicola, icterohaemorrhagiae, and pomona yielded a common precipitating protein antigen that was detected by immunodiffusion and immunoelectrophoresis with all of the antileptospiral sera examined. In cross-absorption and gel diffusion tests, the precipitinogen from each of the strains was shown to be identical. Formaldehyde treatments and heating at 100 degree C suggest that the cellular location of the common antigen is either somatic or subsurface, and Sephadex G-200 gel filtration enabled the isolation of the active fraction of the L. biflexa antigen. Monoprecipitin sera against the common antigen of L. biflexa were produced by immunizing rabbits with specific precipitates in agar. In gel diffusion and immunoelectrophoresis tests the antisera with each of the soluble antigens developed a single precipitin formation, and the antisera agglutinated formolized and heated whole-cell suspensions of serotypes canicola, icterohaemorrhagiae, and pomona at low dilutions. The soluble L. biflexa antigen was evaluated as an immunogen and in passive immunity tests for protection against death and kidney infection in hamsters. No cross-protection occurred when the hamsters were challenged with virulent leptospires. In contrast, the animals vaccinated or administered hamster immune serum before challenge died earlier than the control animals.
Increased Escherichia coli enterotoxin detection after concentrating culture supernatants: possible new enterotoxin detectable in dogs but not in infant mice
Authors: Nalin D R , Levine M M , Young C R , Bergquist E J , McLaughlin J C
Published: June 2021

The heat-stable enterotoxin (ST) of Escherichia coli can be detected by infant mouse or dog intestinal loop tests. These tests differ in that the dog assay uses concentrated culture supernatants and is based on measurements of net intestinal absorption, whereas the mouse test uses unconcentrated supernatants and depends on gross fluid accumulation. To compare the relative sensitivities of these assays, culture supernatants of randomly selected E. coli isolates from 34 Bangalee diarrhea patients were tested for ST in dog loops and infant mice. Supernatants were also tested for heat-labile enterotoxin (LT) in dog loops, Y-1 adrenal cells, and Chinese hamster ovary cells. E. coli supernatants that produced positive responses for both ST and LT in the dog loop assay (ST+/LT+) also produced positive responses when tested for ST in infant mice and for LT in cell lines. Supernatants of strains negative for ST and LT in dog loop (ST-/LT) were also negative in other assays. Of 10 strains positive for just ST in the dog loop test (ST+/LT-), only 5 were ST positive in the standard infant mouse test. Supernatants of the other five strains (dog loop positive, mouse test negative) were then concentrated 100-fold and retested in mice. Three of these five gave consistently positive results after concentration, and two were only intermittently positive. Concentrated supernatants of negative control strains (ST-/LT-) were all negative in mice. The dog assay detects more strains producing ST than the infant mouse test. The infant mouse test, which detects only gross fluid accumulation, failed to detect approximately half of the 10 strains which produced ST alone (ST+/LT-; P = 0.025). Concentrating supernatants for the mouse assay increases sensitivity for detection of ST, but certain E. coli strains produce a variety of ST to which infant mice do not respond.
Growth of clinical isolates of anaerobic bacteria on agar media: effects of media composition, storage conditions, and reduction under anaerobic conditions
Authors: Murray P R
Published: June 2021

The quantitative growth, the colony size, and the rate of growth of 47 clinical anaerobic isolates were compared on five different media, namely Brucella agar, brain heart infusion agar, Columbia agar, Schaedler agar, and tryptic soy agar. There was no significant difference in the quantitative growth of the anaerobes inoculated onto the five media. Although no single medium was superior for the growth of all isolates, 12 of 22 isolates, inoculated onto media stored for 4 weeks or less, grew best on Schaedler agar. The effects of supplementation of the media with reducing agents and reduction of the media before use were also analyzed and were found to be affected by the composition and length of storage of the media, as well as the bacteria tested.
Typing methods for Proteus rettgeri: comparison of biotype, antibiograms, serotype, and bacteriocin production
Authors: Anderson R L , Engley F B
Published: June 2021

Two hunderd five strains of Proteus rettgeri from epidemic and nonepidemic sources were differentiated by a new biotyping scheme, agglutination in O antisera, antimicrobial resistance patterns, and a new scheme based on bacteriocin production. The P. rettgeri were divided into 10 groups by their fermentation of lactose, sucrose, D-mannitol, and salicin. These groups were then subdivided into 19 biotypes by other biochemical reactions. Bacteriocin production was tested by the cross-streak method. Thirty-four bacteriocin-sensitive indicator strains were evaluated, and 16 were selected for the final scheme and used to type the 205 P. rettgeri, which were divided into 15 bacteriocin types. Serologically, 43% of the P. rettgeri were O42, 13% were untypable, 4% were O15, and 3% each were O33, O64, and O84 in addition to 31 remaining serotypes. Strains of P. rettgeri from known outbreaks contained fewer biotypes, O groups, and bacteriocin types and were more resistant to antimicrobial agents than endemic strains. Strains with common patterns with all four marker systems were frequently associated with outbreaks. A strong correlation between multiple antibiotic resistance and bacteriocin production was shown.
Serological identification of group A streptococci from throat scrapings before culture
Authors: Kholy A E , Facklam R , Sabri G , Rotta J
Published: June 2021

The use of a microtechnique (modified nitrous acid extraction) to test samples from 150 school children and from patients with acute follicular tonsillitis has indicated that group A streptococci in the throat can be identified from tonsillar scrapings in 30 min. The results are comparable to the grouping results obtained by standard throat culture techniques and the Lancefield procedure for grouping. No cross-reaction with other bacteria or cellular material occurs. Study has also shown that the nitrous acid extraction yields three- to fourfold more polysaccharides than the Lancefield hot-HCl of Fuller formamide techniques. The use of the microtechnique leads to another 20-fold concentration of the antigen. Immune salting-out effect could be obtained with 1.00 M sodium acetate. Such molarity is too low to cause nonspecific slating out. It leads to a strong ampliciation of the precipitin reaction.
Early detection and identification of Trichophyton verrucosum
Authors: Kane J , Smitka C
Published: June 2021

A new medium for the early detection and identification of Trichophyton verrucosum has been formulated. The key ingredients of the medium are 4% casein and 0.5% yeast extract. T. verrucosum is recognized by its early hydrolysis of casein and very slow growth. Microconidia were produced by 19 out of 35 isolates (54%), and macroconidia were produced by 8 out of 35 isolates (23%). All isolates formed chains of chlamydospores at 37 degrees C, and 24 out of 35 isolates formed chains at 28 degrees C. Nutritional requirements of all 35 strains of T. verrucosum were confirmed. The medium was evaluated by isolating 570 suspected T. verrucosum from skin scrapings. The early detection of hydrolysis, formation of characteristic chains of chlamydospores, and restricted slow growth of this dermatophyte differentiate it from T. schoenleinii.
Phagocytic resistance of Escherichia coli K-1 isolates and relationship to virulence
Authors: Weinstein R , Young L S
Published: June 2021

Blood culture isolates from 133 episodes of Escherichia coli bacteremia were typed for K-1 capsular antigen by immunodiffusion, utilizing equine antiserum raised against meningococcal group B polysaccharide. Twenty-six percent (34 of 133) of these isolates were positive for K-1 antigen. These 133 strains, 34 K-1 and 99 non-K-1, were tested for susceptibility to phagocytosis. K-1 strains were found to be more resistant to clearance (27%) than non-K-1 strains (71%) when tested in an in vitro opsonophagocytic/killing assay containing normal human granulocytes and plasma. Additional studies demonstrated that resistance was due to decreased phagocytosis rather than diminished intraleukocytic killing. K-1 strains obtained from stool showed a similar degree of resistance to phagocytosis when compared with K-1 blood isolates. A comparison of clinical data on non-neonatal patients with E. coli K-1 and non-K-1 bacteremia showed no significant differences in mortality for these two groups. The incidence of shock for patients bacteremic with K-1 strains (74%) was significantly greater than that for patients bacteremic with non-K-1 strains (33%). These differences are attributed to the increased resistance to phagocytosis observed for K-1 versus non-K-1 E. coli isolates.
Evaluation of a Routine Anaerobic Subculture of Blood Cultures for Detection of Anaerobic Bacteremia
Authors: Paisley John W. , Rosenblatt Jon E. , Hall Marsha , Washington John A.
Published: June 2021

The value of a routine 48-h anaerobic subculture of blood cultures was assessed in our laboratory over a 4-month period. Excluding presumed contaminants, anaerobes represented 51 (6.9%) of the total number of 734 positive cultures. Sixteen isolates (all
Bacteroides
) from six patients were detected by the anaerobic subculture. All but one of these were also detected macroscopically. Excluding the one isolate, the routine anaerobic subculture hastened the identification of anaerobic organisms by only 1 day in two patients. We conclude that a routine anaerobic subculture is not indicated for the detection of anaerobic bacteremia.
Recognition and management of bladder bowel dysfunction in children with autism spectrum disorder
Authors: Raturi Shilpee , Li Fay Xiangzhen , Wong Chui Mae
Published: June 2021

Children with autism spectrum disorder (ASD) with rigidities, anxiety or sensory preferences may establish a pattern of holding urine and stool, which places them at high risk of developing bladder bowel dysfunction (BBD). BBD, despite being common, is often unrecognised in children with ASD. With this case report of a 7-year-old girl with ASD presenting with acute retention of urine, we attempt to understand the underlying factors which may contribute to the association between BBD and ASD. Literature review indicates a complex interplay of factors such as brain connectivity changes, maturational delay of bladder function, cognitive rigidities and psychosocial stressors in children with ASD may possibly trigger events which predispose some of them to develop BBD. Simple strategies such as parental education, maintaining a bladder bowel diary and treatment of constipation may result in resolution of symptoms.
Challenges and operative strategy in an unusual case of giant mastoid osteoma
Authors: Marfatia Hetal , Ashwathy Kp , Madhavi Asmita , Goyal Pankaj
Published: June 2021

A 19-year-old female patient presented to the outpatient department of ear, nose and throat with complaints of hard swelling behind her left ear for the past 5 years. It was a large bony swelling arising from the left temporal bone causing a cosmetic deformity that was surgically excised. The patient made a good recovery post procedure. Histopathology confirmed the lesion to be osteoma.
Knowledge, attitude and practice of evidence-based medicine among primary care practitioners in Malaysia: a cross-sectional study
Authors: Zanaridah Mat Nawi , Norhayati Mohd Noor , Rosnani Zakaria
Published: June 2021

Objectives

To determine the level of knowledge and practice of evidence-based medicine (EBM) and the attitudes towards it and to identify the factors associated with its practice among primary care practitioners in Selangor, Malaysia.

Setting

This cross-sectional study was conducted in randomly selected health clinics in Selangor. Data were collected from primary care physicians using self-administered questionnaires on knowledge, practice and attitudes regarding EBM.

Participants

The study included 225 respondents working in either government or private clinics. It excluded house officers and those working in public and private universities or who were retired from practice.

Results

A total of 32.9% had a high level of EBM knowledge, 12% had a positive attitude towards EBM and 0.4% had a good level of its practice. The factors significantly associated with EBM practice were ethnicity, attitude, length of work experience as a primary care practitioner and quick access to online reference applications on mobile phones.

Conclusions

Although many physicians have suboptimal knowledge of EBM and low levels of practising it, majority of them have a neutral attitude towards EBM practice. Extensive experience as a primary care practitioner, quick access to online references on a mobile phone and good attitude towards EBM were associated with its practice.
Resveratrol upregulates miR-455-5p to antagonize cisplatin ototoxicity via modulating the PTEN–PI3K–AKT axis
Authors: Liu Yupeng , Wu Hui , Zhang Fan , Yang Jun , He Jingchun
Published: June 2021

Resveratrol is a non-flavonoid polyphenol compound that exists in many plants, and is considered an antitoxin. This study explores the effects from the regulation of miR-455-5p by resveratrol on cisplatin-induced ototoxicity via the PTEN–PI3K–AKT signaling pathway. For this, House Ear Institute–Organ of Corti 1 (HEI-OC1) cells were transfected with miR-455-5p inhibitor and treated with cisplatin and resveratrol, then cell proliferation, apoptosis, and oxidative stress were evaluated. A mouse model of hearing loss was established, and these mice were treated with cisplatin, resveratrol, or cisplatin combined with resveratrol, by intraperitoneal injection. The auditory brainstem response (ABR) threshold was measured, and hair cells were examined using immunofluorescence staining. The expression levels of miR-455-5p, PTEN, and PI3K/Akt proteins were examined. The results from our in-vitro experiments indicate that resveratrol promoted viability and reduced apoptosis and oxidative stress in cisplatin-induced HEI-OC1 cells. Resveratrol upregulated miR-455-5p, downregulated PTEN, and activated the PI3K–Akt axis. These effects of resveratrol were reversed by knock-down of miR-455-5p. The results from our in-vivo experiments indicate that resveratrol protected hearing and inhibited the hair-cell injury caused by cisplatin ototoxicity. Resveratrol also upregulated miR-455-5p, downregulated PTEN, and activated the PTEN–PI3K–Akt axis in cochlear tissues from cisplatin-treated mice. These results indicate that resveratrol upregulates miR-455-5p to target PTEN and activate the PI3K–Akt signaling pathway to counteract cisplatin ototoxicity.
New method for the production of thin and stable, segmented n$$+$$ contacts in HPGe detectors
Authors: Bertoldo S. , Maggioni G. , Raniero W. , Carraro C. , Riccetto S. , Sgarbossa F. , Scarpa D. , Andrighetto A. , Mazzolari A. , Gadea A. , Napoli D. R. , Napolitani E. , De Salvador D.
Published: June 2021

The realization of pulsed-laser diffused, thin n$$+$$+contacts on high purity germanium (HPGe) and their successful segmentation is described. The contacts have been obtained by a laser-induced diffusion of Sb atoms, deposited by sputtering on Ge surface, and then segmented by means of a photolithographic technique. Three small prototypes of gamma ray detectors have been implemented, using the same n$$+$$+contact (laser diffused Sb) but with three different geometries and a B implanted p$$+$$+contact. Electrical and detection properties of the prototypes have been characterized, showing low leakage currents and good spectroscopy data with different gamma-ray sources. The stability of the detector performance has also been tested subjecting one of the prototypes to a typical annealing treatment.
Averaging generalized scalar field cosmologies II: locally rotationally symmetric Bianchi I and flat Friedmann–Lemaître–Robertson–Walker models
Authors: Leon Genly , Cuéllar Sebastián , González Esteban , Lepe Samuel , Michea Claudio , Millano Alfredo D.
Published: June 2021

Scalar field cosmologies with a generalized harmonic potential and a matter fluid with a barotropic equation of state (EoS) with barotropic index $$\gamma $$
γ
for the locally rotationally symmetric (LRS) Bianchi I and flat Friedmann–Lemaître–Robertson–Walker (FLRW) metrics are investigated. Methods from the theory of averaging of nonlinear dynamical systems are used to prove that time-dependent systems and their corresponding time-averaged versions have the same late-time dynamics. Therefore, the simplest time-averaged system determines the future asymptotic behavior. Depending on the values of $$\gamma $$
γ
, the late-time attractors of physical interests are flat quintessence dominated FLRW universe and Einstein-de Sitter solution. With this approach, the oscillations entering the system through the Klein–Gordon (KG) equation can be controlled and smoothed out as the Hubble parameter H – acting as time-dependent perturbation parameter – tends monotonically to zero. Numerical simulations are presented as evidence of such behavior.
The great Chinese fireball of December 22, 2020
Authors: Carbognani Albino
Published: June 2021

On December 22, 2020, at about 23h 23m 33s UTC a very bright fireball was seen in the sky of southeastern China. The fireball lasted for several seconds and ended with an atmospheric explosion that was detected by US surveillance satellites. According to CNEOS’s data, the fireball moved with a mean speed of 13.6 km/s and exploded at an altitude of about 35.5 km (Lat. $$31.9^{\circ }$$

31
.

9
∘

N; Long. $$96.2^{\circ } $$

96
.

2
∘

E). In this paper we estimate the atmospheric trajectory, the heliocentric orbit and the strewn fields for different mass/section ratio of the fragments. The trajectory was about from north to south and with low inclination ($$5^{\circ } \pm 2^{\circ }$$

5
∘

±

2
∘

) with respect to the local surface. The explosion height appears consistent with a fragmented rocky body, and the heliocentric orbit supports an asteroidal origin. The probable strewn field extends between two points with coordinates ($$+31.3^\circ $$

+
31
.

3
∘

N; $$96.3^\circ $$

96
.

3
∘

E) and ($$+30.3^\circ $$

+
30
.

3
∘

N; $$96.5^\circ $$

96
.

5
∘

E), for a total area of about 4000 $$\text {km}^2$$

km
2

. This large extension is a direct consequence of the low inclination of the trajectory. Given the unknown uncertainty of the CNEOS’s data, these results should be taken with caution.
From black hole to white hole via the intermediate static state
Authors: Volovik G. E.
Published: June 2021

We discuss the macroscopic quantum tunneling from the black hole to the white hole of the same mass. Previous calculations in [G. E. Volovik, Universe 6, 133 (2020)] demonstrated that the probability of the tunneling is [Formula: see text], where [Formula: see text] is the entropy of the Schwarzschild black hole. This in particular suggests that the entropy of the white hole is with minus sign the entropy of the black hole, [Formula: see text]. Here, we use a different way of calculations. We consider three different types of the hole objects: black hole, white hole and the fully static intermediate state. The probability of tunneling transitions between these three states is found using singularities in the coordinate transformations between these objects. The black and white holes are described by the Painleve–Gullstrand coordinates with opposite shift vectors, while the intermediate state is described by the static Schwarzschild coordinates. The singularities in the coordinate transformations lead to the imaginary part in the action, which determines the tunneling exponent. For the white hole the same negative entropy is obtained, while the intermediate state — the fully static hole — has zero entropy. This procedure is extended to the Reissner–Nordström black hole and to its white and static partners, and also to the entropy and temperature of the de Sitter Universe.