bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential medium for detecting dental plaque bacteria resembling Actinomyces viscosus and Actinomyces naeslundii
Authors: Ellen R P , Balcerzak-Raczkowski I B
Published: June 2021

A medium for detecting colonies of Actinomyces viscosus and Actinomyces naeslundii in dental plaque samples was developed. The medium (CNAC-20) contains 20.0 mug of 3CdSO4-8H2O per ml of Columbia CNA agar base. Laboratory strains of A. viscosus grew on CNAC-20 in characteristic round, white, smooth, opaque colonies. Increasing the cadmium concentration impaired the growth of some A. viscosus strains. Stock strains of A. naeslundii and A. israelii grew in colonies of similar white, opaque morphology. The few strains of other gram-positive plaque bacteria that grew on CNAC-20 had colonies easily distinguished from those of A. viscosus. Most of the bacterial strains freshly isolated from Actinomyces-like colonies on CNAC-20 that had been inoculated with human dental plaque samples were found to have cultural characteristics consistent with previous descriptions of A. viscosus or A. naeslundii. CNAC-20 may facilitate investigations into the relationship of microaerophilic Actinomyces with the etiology of dental diseases.
Phage typing scheme for group D streptococci isolated from human urogenital tract
Authors: Caprioli T , Zaccour F , Kasatiya S S
Published: June 2021

Streptococci of Lancefield group D were isolated from 52.2% of pharyngeal, 55.5% of urethral, 56.6% of endocervical, and 75.4% of ano-rectal specimens. Seventeen phages isolated from sewage and urogenital specimens were selected for phage typing. Four of these lysed only the strains of Streptococcus faecalis and its variety liquefaciens. Another six phages lysed only the strains of Streptococcus faecium and its variety durans. With the help of seven bacteriophages, 346 of 384 (90.1%) strains of S. faecalis and its variety liquefaciens could be classified into 27 types. Similarly, with the help of 10 other bacteriophages, 97 of 117 (82.9%) strains of S. faecium and its variety durans could be grouped into 22 types. In 72 of 87 (82.7%) cases, similar phage types were obtained at different culture sites of the same individual.
Efficacy of phage typing epidemiologically related Staphylococcus epidermidis strains
Authors: Blouse L , Kolonel L N , Watkins C A , Atherton J M
Published: June 2021

A total of 118 epidemiologically related Staphylococcus epidermidis strains from hospital patients, staff, and fomites were examined with a provisional set of 18 typing phages. Seventy (59.3%) of these strains were typed using phage concentrations of 100 times routine test dilution. The remainder were nontypable. Thirty-six (30.5%) of the strains were of related phage types, 71/108/275A/459 and 71/108/275A. These latter strains were associated with clinical S. epidermidis endocarditis in patients with prosthetic valve replacements. Ninety-eight strains were characterized by the Baird-Parket biotyping schema. Eighty-three (84.7%) were biotype 1, and the majority (68.4%) of these were resistant to penicillin, ampicillin, methicillin, cephalothin, erythromycin, and clindamycin. Type 71, 71/108/275A/459, 71/108/275A and 71/108/275/459 strains were generally resistant to penicillin, ampicillin, erythromycin, and methicillin, whereas a less consistent resistance pattern was noted among miscellaneous and nontypable strains.
Reproducibility of the analytab (API 20E) system
Authors: Butler D A , Lobregat C M , Gavan T L
Published: June 2021

The reproducibility of the Analytab (API 20E) system for identification of Enterobacteriaceae was evaluated with 110 clinical isolates. Each isolate was identified by two technologists at different times. Genus-species identification was 97.3% reproducible; however, only 55.5% of the strains gave identical reactions in all 20 of the API 20E biochemical tests on repeat testing. Of those strains which varied, 56% possessed only one variable biochemical test. The reproducibility for each biochemical test was calculated and ranged from 89 to 100%. A subset of 20 of the most variable strains was tested further under conditions of varying incubation time (15 and 22 h) and inoculum concentration (10(7), 10(5), and 10(3) colony-forming units per ml), and by having four technologists interpret the test results. The reproducibility for each biochemical test for these 20 variable strains ranged from 86 to 99%. Less variation in interpretation by technologists was seen at an incubation time of 22 h and an inoculum concentration of 10(7) colony-forming units per ml. Consideration of the reproducibility for each biochemical test can aid in determining the probability that two isolates suspected of being the same strain, but with API profiles which differ by one or more biochemical test results, are in fact the same strain. Variables such as inoculum size, incubation time, technologist interpretation, and strip variability affect the API test results and should be standardized to minimize their effects.
Demonstration of immunoglobulin G receptors induced by human cytomegalovirus
Authors: Furukawa T , Hornberger E , Sakuma S , Plotkin S A
Published: June 2021

Human cytomegalovirus induced a new immunoglobulin G receptor in human fibroblasts. The immunoglobulin G receptor was well localized in the perinuclear region at 48 h postinfection, and antiviral agents blocked its synthesis. The immunoglobulin G receptor bound immunoglobulin G of man and several other species. It may be a source of error in the performance of indirect fluorescence tests for human cytomegalovirus antibody.
Indirect fluorescent antibody procedure for the rapid detection and identification of Bacteroides and Fusobacterium in clinical specimens
Authors: Stauffer L R , Hill E O , Holland J W , Altemeier W A
Published: June 2021

An indirect fluorescent antibody (IFA) technique was evaluated as a procedure for rapid detection and identification of members of the Bacteroidaceae. Antisera were prepared against 31 members of this family, including species of Bacteroides and Fusobacterium commonly isolated from human infections. The antisera had demonstrated species and/or subspecies specificity. Thirty clinical specimens were studied. Of 13 specimens yielding Bacteroidaceae, for which antisera were available, 23 were presumptively diagnosed by IFA to contain subspecies of B. fragilis and/or Fusobacterium species. Of 17 specimens yielding negative culture results, two were positive by IFA on direct smear. Frequently the in vivo morphology of cells detected in direct smears by this procedure closely mimicked that of cellular debris, tissue cells, and leukocytes. Polyvalent antisera pools facilitated use of the IFA procedure as a practical tool for rapid diagnosis of infections involving the Bacteroidaceae.
Germ tube and chlamydospore formation by Candida albicans on a new medium
Authors: Beheshti F , Smith A G , Krause G W
Published: June 2021

A new medium composed of "cream of rice" infusion, oxgall, Tween 80, and agar is described for the sequential development of germ tubes and chlamydospores by Candida albicans. The procedure used (Dalmau's technique) is an improvement over the fluid substrate procedures previously advocated for germ tube formation. That the same preparation is then used for chlamydospore production is of practical importance for the clinical mycology laboratory.
Evaluation of the Uni-Yeast-Tek kit for the identification of medically important yeasts
Authors: Bowman P I , Ahearn D G
Published: June 2021

The Uni-Yeast-Tek system, a commercially prepared kit and scheme for the rapid identification of medically important yeasts (Corning Medical), was evaluated in comparison with a conventional procedure in the identification of 623 yeasts. The system permitted the presumptive identification of 99.8% of 436 isolates representing 16 common species commonly isolated in the clinical laboratory. Correct biochemical and morphological analyses were obtained with 48 other species, but their specific identification required additional data.
Formalinized bacterial "antigens" as a potential infection hazard
Authors: Farmer J J
Published: June 2021

It is widely thought that after enteric bacteric have been "formalinized" (treated with an equal volume of 0.6% formalin) for 1 h, the bacteria become "antigens" and are no longer viable. None of the 27 cultures of Salmonella and other Enterobacteriaceae were entirely killed within 1 h after formalin was added, but all 27 were reduced from 10(9) viable cells per ml to less than 10(2) per ml within 7 h. Thus, mouth pipetting of cultures formalinized for only 1 h is a possible infection hazard.
Thin-layer chromatographic technique for rapid detection of bacterial phospholipases
Authors: Legakis N J , Papavassiliou J
Published: June 2021

Silica gel thin-layer chromatography was employed to detect lecithinase activity induced from bacterial resting cell preparations induced from bacterial resting cell preparations incubated at 37 C for 4 h in the presence of purified egg yolk lecithin. Bacillus subtilis, Bacillus cereus, Serratia marcescens, and Pseudomonas aeruginosa hydrolyzed lecithin with the formation of free fatty acids as the sole lipid-soluble product. In none of the Escherichia coli and Citrobacter freundii strains tested could lecithinase activity be detected. Four among eight strains of Enterobacter aerogenes and one among 12 strains of Proteus tested produced negligible amounts of free fatty acid.
Seroepidemiological investigation of Brucella canis antibodies in different human population groups
Authors: Monroe P W , Silberg S L , Morgan P M , Adess M
Published: June 2021

A study was conducted to determine the prevalence of Brucella canis antibodies in specified groups based on their exposure to dogs. The method used was a microtiter technique, and the presence of antibodies at a 1:12 or greater dilution of serum was considered a positive test. Eleven (5.7%) of the newborn infants had evidence of maternal antibodies, and 67.8% of the persons with an average exposure to dogs had B. canis antibodies, with a 62.1% prevalence in males and a 72.4% prevalence in females (P less than or equal to 0.001). Veterinarians had a much higher rate of infection (72.6%) than male blood donors (56.9%) (P less than or equal to 0.01). Patients with fevers of undetermined origin had significantly higher antibody titers to B. canis than all other patients (P less than or equal to 0.001). This study presents evidence that the prevalence of B. canis antibodies in humans is high, and that the incidence of brucellosis may increase when physicians consider B. canis as a possible etiological agent in febrile illnesses.
Conditions required for the attainment of colony-type stability of Neisseria gonorrhoeae in liquid culture
Authors: Hart E J , Goldberg I D
Published: June 2021

Colony-type morphology in Neisseria gonorrhoeae is associated with virulence, transformability, and the presence or absence of pili. A reliable method for achieving large populations of cells that are relatively stable with respect to colony type would be valuable, for example, in studies of virulence or for the isolation of pilus-specific phages. Previously described methods designed to achieve type stability in liquid culture were inadequate for a variety of reasons, including their low final cell yields and/or their requirements for prolonged incubation. The success of the procedure described in this communication depends upon the use of an overnight plate harvest to insure a relatively large and stable inoculum for the liquid medium. Yields of as high as 10(10) colony-forming units/ml are routinely obtained after 4 to 5 h of incubation. Such cultures exhibit a colonial-type stability of 85 to 95% with respect to the original colonial type used for inoculation of the start plate.
Discriminant analysis of antibiotic susceptibility as a means of bacterial identification
Authors: Darland G
Published: June 2021

This study shows that antibiotic susceptibility data can be used effectively in the presumptive identification of bacteria. Using 12 antibiotics and determining the zone sizes for each, 82% of the isolates considered were correctly identified without any other information. If the inability to distinguish between Escherichia coli and Shigella is disregarded, the percentage of correct identification is 92%. The method involves determining a set of discriminant functions and defining each taxon by a unique function. An unknown isolate is identified by evaluating each discriminant function and assigning the isolate to the taxon whose discriminant function has the largest value. A total of 468 isolates were examined. After eliminating the multiply resistant isolates, the remaining 369 isolates were used to determine the discriminant functions for the eight taxa considered.
Attenuated influenza A vaccine (Alice) in an adult population: vaccine-related illness, serum and nasal antibody production, and intrafamily transmission
Authors: Minor T E , Dick E C , Dick C R , Inhorn S L
Published: June 2021

Ninety-five healthy adults, ages 18 to 56 years, received two intranasal doses, 2 weeks apart, of a live, attenuated, influenza type A (H3N2) vaccine (an inhibitor-resistant recombinant strain of A/England/42/72 named "Alice"). Ninety-two persons were given placebos similarly. Ninety-three percent of 68 subjects with initial serum hemagglutination-inhibition (HI) titers of greater than or equal to 1:40 to influenza A (H3N2) had a fourfold or greater antibody increase in postvaccination sera. Forty-four percent of 27 subjects with an initial HI titer of greater than or equal to 1:80 had similar increases. Overall, 77% of vaccinees had fourfold or greater antibody titer increases. Vaccinees had geometric mean serum HI titers (GMT) of 1:26, 1:123, and 1:166 at 0, 14, and 30 days, respectively. The GMTs for placebos were 1:21, 1:22, and 1:21. Thirty-five vaccinees were examined for both serum and nasal antibody; 89% had significant increases in one or both. Nasal antibody response was directly related to the level of initial serum HI titer in that 83% of 12 persons with prevaccination HI titers of 1:80 greater than or equal to 1:80 showed significant nasal antibody rises, whereas only 61% of the remaining 23 subjects with prevaccination HI titers of less than or equal to 1:40 did so. The number and severity of clinical signs and symptoms reported by vaccinees and placebos did not differ significantly. The greatest differences noted between groups were for nasal congestion on days 0 to 6 (8.3%) and rhinitis on days 14 to 20 (5.9%). Four vaccinees shed Alice after primary vaccination, but viral titers were low (10 to 100 tissue culture-infective doses/ml). One member in each of 15 cohabiting male-female couples received Alice while the other received a placebo; one of the placebo members had significant increases in serum and nasal antibody, indicating a possible transmission.
Solid phase radioimmunoassay for typing herpes simplex viral antibodies in human sera
Authors: Forghani B , Schmidt N J , Lennette E H
Published: June 2021

An indirect solid phase radioimmunoassay (RIA) was developed for typing antibody to herpes simplex virus (HSV) types 1 and 2 (HSV-1 and HSV-2) in human sera. The test is based upon absorption of sera with uninfected, HSV-1-infected cells and testing for residual antibody. The high sensitivity of the RIA method for detecting HSV antibody permits examination of sera at high dilutions, and thus relatively small volumes of virus-infected cells are required for cross-absorption of antibodies. Results obtained in RIA typing of HSV antibodies showed good agreement with those obtained by microneutralization and inhibition of passive hemagglutination. The HSV antibody type(s) determined by RIA also showed good correlation with the virus type isolated from the individual, either from clinical specimens or sensory nerve ganglia. The technique was very sensitive for detection and typing of HSV antibdodies in cerebrospinal fluids. The RIA method was highly suitable for detecting two types of HSV antibody in the same serum specimen, and it was possible to show that a marked, type-specific antibody response to HSV-2 does occur in individuals with a primary HSV-2 infection who have experienced a prior infection with HSV-1.
Relationship of indole production and antibiotic susceptibility in the Klebsiella bacillus
Authors: Klein D , Spindler J A , Matsen J M
Published: June 2021

Of 2,442 Klebsiella strains isolated from clinical specimens at the University of Minnesota hospitals, 18.3% were found to be indole positive. A randomly selected equal number of indole-positive and indole-negative control isolates, characterized by 27 biochemical tests and by serotyping against 72 antisera, were tested against 14 antibiotics. The results indicated a greater incidence of multiple drug resistance among the indole-negative strains among those that produced indole. The organisms in the former group, in comparison to their indole-positive counterparts, were significantly more resistant to nitrofurantoin, tetracycline, chloramphenicol, neomycin, streptomycin, nalidixic acid, and kanamycin. Both groups of organisms were similar in their degree of resistance to ampicillin, carbenicillin, cephalothin, sulfisoxazole, colistimethate, polymyxin B, and gentamicin. The biochemical properties of the two indole groups were essentially identical. Correlation between serotype and multidrug resistance was inapparent.
Anaerobic specimen transport device
Authors: Wilkins T D , Jimenez-Ulate F
Published: June 2021

A device is described and evaluated for the anaerobic transport of clinical specimens. The device limits the amount of oxygen entering with the sample to a maximum of 2%, which is rapidly removed by reacting with hydrogen in the presence of a palladium catalyst. The viability on swabs of 12 species of anaerobes, four strains of facultative anaerobes and a strain of Pseudomonas aeruginosa, was maintained during the length of the tests (24 or 48 h). The results demonstrated that this device protected even the more oxygen-sensitive clinical anaerobes from death due to oxygen exposure. This device can be used for swabs as well as for anaerobic collection and liquid and solid specimens.
Methods to improve detection of pneumococci in respiratory secretions
Authors: Dilworth J A , Stewart P , Gwaltney J M , Hendley J O , Sande M A
Published: June 2021

Simple methods to enhance the detection of pneumococci in respiratory secretions are needed. Sheep blood agar containing 5 mug of gentamicin per ml was more often positive (89%) than either standard sheep blood agar (54%) or mouse inoculation (65%) in recovering pneumococci from 62 adult and pediatric patients. In adults, the direct quellung test on sputum smear was a rapid, sensitive method for predicting subsequent pneumococcal isolation by culture (19 of 20 patients, 95%). The quellung test and gentamicin plate show improved sensitivity over current techniques for pneumococcal detection and can be recommended for general use.
Unusual Colonies of
Ureaplasma urealyticum
(T Mycoplasmas) in Primary Agar Cultures of Certain Urine Specimens
Authors: Shepard M. C. , Lunceford C. D.
Published: June 2021

The existence of unusual colonies of
Ureaplasma urealyticum
(T mycoplasmas) in primary agar cultures of certain urine specimens is reported and their morphology is illustrated.
Modified Fluorescent Antibody Technique to Detect Immunoglobulin M Antibodies to
Toxoplasma gondii
in Congenital Infection
Authors: Robertson P. W. , Kertesz Vera
Published: June 2021

Using a modified fluorescent antibody technique immunoglobulin M antibodies to
Toxoplasma gondii
were studied in infants' sera. The modified technique involved prolonged incubation of patients' sera with antigen at 4 C.
Color Reaction Streak Test for Catalase-Positive Microorganisms
Authors: Hanker Jacob S. , Rabin Albert N.
Published: June 2021

A stable purple color results when a reagent solution is applied to a smear of catalase-positive organisms streaked on a glass slide.
Sensitivity of infectious bovine rhinotracheitis virus to ether
Authors: Crandell R A , Melloh A J , Sorlie P
Published: June 2021

The sensitivity of 12 field isolates of infectious boviine rhinotracheitis (IBR) virus and four commercial modified-live infectious bovine rhinotracheitis virus vaccine strains was determined after exposure to 20% ethyl ether (anesthetic) for 16 h at 4 c. The infectivity of five field strains was reduced by varying degrees, whereas seven were found to be resistant. Three vaccine strains were moderately sensitive, and one strain was resistant. Four of the sensitive field strains were isolated from the conjunctiva and the other was isolated from the surface of the epiglottis of natural infective cattle. Strains of virus isolated from fetal tissue and nasal cavity were resistant. All viruses were readily inactivated by chloroform treatment.
Direct inoculation procedure for the rapid classification of bacteria from blood culture
Authors: Edberg S C , Novak M , Slater H , Singer J M
Published: June 2021

A procedure was developed for 4-h identification of bacteria from blood culture. From a turbid blood culture bottle a 10- to 15-ml aliquot was drawn off and centrifuged. The pellet was utilized to inoculate a series of enzymatic and physiologic reactions. Three hundred eight positive blood cultures were tested including 222 strains of Enterobacteriaceae, 40 strains of facultative grampositive cocci, 26 strains of anaerobes, and 20 assorted strains. There was over 96.5% agreement between 4-h and conventional methods with the Enterobacteriaceae, 98% with facultative gram-positive cocci, 100% with anaerobes, and 99% with the assorted strains.
New microtechnique for the leptospiral microscopic agglutination test
Authors: Carter P L , Ryan T J
Published: June 2021

A new microtechnique has been developed for the detection of leptospiral antibodies in serum by the microscopic agglutination test. The test was set up in a microtiter transfer plate held in a transfer plate holder, resting on a transfer plate cover. Live leptospiral antigen was added and a second transfer plate cover was placed over the transfer plate during 2 h of incubation at 32 C. After incubation the bottom cover was removed and the complete unit was placed in a specially designed base plate containing microscope slides (50 by 75 mm). The serum/antigen mixture was ejected on to the microscope slides by means of a sharp tap. The agglutination was then read using a 10 X objective, 10 X eyepieces, and a dry, dark field condenser.
Isolation of Yersinia enterocolitica from swine
Authors: Toma S , Deidrick V R
Published: June 2021

Data pertaining to 20 strains of Yensinia enterocolitica isolated from the cecal content of swine slaughtered at Toronto Abattoirs are presented. Fifteen of 20 cultures belonged to the two predominant human serotypes in Ontario (i.e., serotype O:3 and O:5,27.) Seven cultures of Y. enterocolitica O:3 belonged to the "Canadian" human phage type 9b. These findings are further proof that swine are reservoirs for Y. enterocolitica human infection. Seventeen Y. enterocolitica cultures were isolated by the cold enrichment method only. Difficulties encountered in isolating Y. enterocolitica from feces specimens are discussed. It would appear that the reported rate of Y. enterocolitica isolation from feces specimens is far below the actual incidence. Fourteen isolates of Y. pseudotuberculosis serotype III were isolated during the same survey.
Detection of Aspergillus fumigatus serum precipitins by counterimmunoelectrophoresis
Authors: Dee T H
Published: June 2021

Detection of serum precipitins to Aspergillus fumigatus by counterimmunoelectrophoresis is compared with the immunodiffusion technique. Eight of nine (89%) sera from patients with proven A. fumigatus infection were positive by both methods. No serum from subjects with other systemic mycoses, bacterial infections, or healthy controls had detectable precipitins. The highest serum precipitin titers were found in sera of patients with the mycetomal and invasive forms of the disease. Detection of A. fumigatus serum precipitins by counterimmunoelectrophoresis compares favourably with immunodiffusion and has the advantage of significantly reducing the time required for results.
Counterimmunoelectrophoresis of pneumococcal antigens:improved sensitivity for the detection of types VII and XIV
Authors: Anhalt J P , Yu P K
Published: June 2021

Rapid identification of Streptococcus pneumoniae has been reported using counterimmunoelectrophoresis for the detection of specific capsular antigens in serum, cerebrospinal fluid, and urine. Previous clinical studies have failed to detect type VII or XIV pneumococcal antigen. These two types, however, account for a significant portion of pneumococcal disease. The incorporation of a sulfonated derivative of phenylboronic acid in the buffer system provides a method for the sensitive detection of these types in artificial mixtures without greatly reducing the sensitivity for the detection of other pneumococcal types. A problem with false positives encountered using human serum and barbitalbuffer was reduced by the use of buffer containing sulfonated phenylboronic acid.
Epidemiologic study of a leukocyte-transforming agent in a general population
Authors: Sumaya C V
Published: June 2021

Studies by others have demonstrated a leukocyte-transforming agent(s) (LTA) in the oropharyngeal secretions of a significant number of individuals with Epstein-Barr virus-associated infectious mononucleosis, cancer, and, to a lesser extent, an outpatient population. This present study determines by systematic sampling the prevalence of LTA in 27 families of a semirural community. Throat swab inoculums from three of 54 adults and none of 44 children induced transformation of umbilical cord lymphocytes. Complement-dependent Epstein-Barr virus nuclear antigen was detected in two of the three transformed cell cultures. The three LTA-positive individuals were characterized by the absence of serologic evidence of a recent Epstein-Barr virus infection and the lack of elevated antibodies against the viral capsid antigen of Epstein-Barr virus.
Evaluation of a microscopy method for rapid detection and identification of Mycoplasma pneumoniae
Authors: Bredt W , Lam W , Berger J
Published: June 2021

A microscopy test that used the typical shape of Mycoplasma pneumoniae cells growing on glass was investigated for its value for diagnostic purposes. Suspensions from 108 throat swabs were infected artificially with 102, 103, and 104 colony-forming units of three M. pneumoniae strains per ml. Agar medium, a diphasic medium, and the microscopy method with liquid medium in cover slip chambers were compared for isolation of the mycoplasmas. The mycoplasms were detected first by the microscopy method in nearly all concentrations tested. Typical M. pneumoniae cells could often be detected after 48 h. No differences were found between a laboratory strain and two low-passage strains. The experimental results suggest that under special circumstances the microscopy method could be a useful tool for isolation and identification of M. pneumoniae.
Rapid screening of Veillonella by ultraviolet fluorescence
Authors: Chow A W , Patten V , Guze L B
Published: June 2021

Among 51 strains of anaerobic gram-negative cocci belonging to the family Veillonellaceae, all strains of Veillonella (V. parvula and V. alcalescens) displayed red fluorescence under long-wave (366 nm) ultraviolet light, whereas no Acidaminococcus or Megasphaera demonstrated fluorescence. In contrast to Bacteroides melaninogenicus, growth of Veillonella does not require hemin and menadione, and flourescence is rapidly lost upon exposure to air. The fluorescent component of a strain of V. parvula examined could not be extracted in solution with water, ether, methanol, or chloroform, but was readily extracted with 0.4 N NaOH. Spectrophotofluorometrically, the fluorescence maximum of this extract was 660 nm with an excitation maximum of 300 nm, when measured at pH 7.2 and 25 C. Coupled with the Gram stain, ultraviolet fluorescence may be a useful tool for rapid screening of Veillonella and is particularly helpful for detection and, isolation of this organism from mixed culture.
Retention of Mercurial Preservatives in Desiccated Biological Products
Authors: Pemberton John R.
Published: June 2021

A variety of bacterins, vaccines, and antisera retained greater than 90% of their original level of mercurial preservative after lyophilization, and this might influence certain uses of these products.
Convenient, Simplified Preparation of Less Commonly Used Media
Authors: von Riesen V. Lyle
Published: June 2021

A method is described for the preparation of some less commonly used media. This approach should encourage use of these media.
Bacteriophage: A Model System for Active Learning
Authors: LUCIANO CARL S. , YOUNG MATTHEW W. , PATTERSON ROBIN R.
Published: June 2021

Although bacteriophage provided a useful model system for the development of molecular biology, its simplicity, accessibility, and familiarity have not been fully exploited in the classroom. We describe a student-centered laboratory course in which student teams selected phage from sewage samples and characterized the phage in a semester-long project that modeled real-life scientific research. The course used an instructional approach that included active learning, collaboration, and learning by inquiry. Cooperative student teams had primary responsibility for organizing the content of the course, writing to learn using a journal article format, involving the entire group in shared laboratory responsibilities, and applying knowledge to the choice of new experiments. The results of student evaluations indicated a high level of satisfaction with the course. Our positive experience with this course suggests that phage provides an attractive model system for an active-learning classroom.
Development of a Microbiology Course for Diverse Majors; Longitudinal Survey of the Use of Various Active, Problem-Based Learning Assignments
Authors: CUNDELL DIANA R.
Published: June 2021

Educators are increasingly being encouraged to use more active- and problem-based-learning techniques and assignments in the classroom to improve critical and analytical thinking skills. Active learning-based courses have been purported to be more time consuming than traditional lecture methods and for many instructors have therefore proven difficult to include in many one-semester science courses. To address this problem, a series of assignments was developed for use in a basic microbiology course involving sophomore-, junior-, and senior-level students from five different biology majors (environmental science, biology, biochemistry, premedicine, and physician assistant). Writing assignments included global, historical, and social themes for which a standardized grading format was established. Students also participated in a class debate in which the merits of the living microbial kingdoms were discussed, with only one kingdom being saved from an imaginary global catastrophe. Traditional lectures were facilitated by the use of a dedicated note packet developed by the instructor and specific for course content. Laboratories involved group analysis of mini-case history studies involving pathogenic microbes. Students’ perceptions of the subject were assessed using an exit questionnaire sent to 100 of the 174 students who had taken the course during the 5-year time period. The majority of the 64 students who responded were sophomores (78%), in keeping with the target audience, and their perception of the course’s challenge level was significantly higher (p < 0.03, 8.7) than their junior and senior counterparts (7.9). Students rated the most useful learning tools as case history studies (9.4) and the class debate (9.1), with the introduction of a dedicated microbiology links web page to the University website representing the sole component resulting in a statistically significant increase in students’ perceptions of the importance of the course (p < 0.03).
Bacterial Diversity Studies Using the 16S rRNA Gene Provide a Powerful Research-Based Curriculum for Molecular Biology Laboratory
Authors: BOOMER SARAH M. , LODGE DANIEL P. , DUTTON BRYAN E.
Published: June 2021

We have developed a ten-week curriculum for molecular biology that uses 16S ribosomal RNA genes to characterize and compare novel bacteria from hot spring communities in Yellowstone National Park. The 16S rRNA approach bypasses selective culture-based methods. Our molecular biology course offered the opportunity for students to learn broadly applicable methods while contributing to a long-term research project. Specifically, students isolated and characterized clones that contained novel 16S rRNA inserts using restriction enzyme, DNA sequencing, and computer-based phylogenetic methods. In both classes, students retrieved novel bacterial 16S rRNA genes, several of which were most similar to Green Nonsulfur bacterial isolates. During class, we evaluated student performance and mastery of skills and concepts using quizzes, formal lab notebooks, and a broad project assignment. For this report, we also assessed student performance alongside data quality and discussed the significance, our goal being to improve both research and teaching methods.
Learning Microbiology Through Cooperation: Designing Cooperative Learning Activities that Promote Interdependence, Interaction, and Accountability
Authors: TREMPY JANINE E. , SKINNER MONICA M. , SIEBOLD WILLIAM A.
Published: June 2021

A microbiology course and its corresponding learning activities have been structured according to the Cooperative Learning Model. This course,
The World According to Microbes
, integrates science, math, engineering, and technology (SMET) majors and non-SMET majors into teams of students charged with problem solving activities that are microbial in origin. In this study we describe development of learning activities that utilize key components of Cooperative Learning—positive interdependence, promotive interaction, individual accountability, teamwork skills, and group processing. Assessments and evaluations over an 8-year period demonstrate high retention of key concepts in microbiology and high student satisfaction with the course.
An Activity-Based Format Increased Student Retention in a Community College Microbiology Course
Authors: LUX MARY F.
Published: June 2021

Microbiology is offered each semester at the Allied Health Campus of Pearl River Community College. The evening course meets weekly for 16 sessions from 5 p.m. to 10 p.m. Most students enrolled in the course are in one of the seven associate degree allied health programs on the allied health campus. Among the challenges of teaching a course in this situation is retention of enrolled students. Although the course is required for most of the allied health programs on the campus, many students enrolled, attended class for a few weeks, and withdrew from the course. During the 1998–1999 school year the retention rates for students enrolled in the night microbiology classes for Fall and Spring semesters were 52% and 47%, respectively. The format for the 1998–1999 academic year was a conventional course with 2½ hours of lecture material followed by 2 hours of laboratory. Little or no effort was made to correlate laboratory and lecture topics. The course format for Fall 1999 was modified to (i) provide the laboratory component at the beginning of the time slot, (ii) tailor the lecture topics to relate to the laboratory component each night, and (iii) add an outside reading component. The laboratory served as an introduction to the lecture topic, and the lecture became more significant since it related directly to the laboratory experience. Following this format change the retention rate for the Fall 1999 semester increased to 80%.
Two Metagenome-Assembled Genomes of Hydrogen-Dependent
Methanomassiliicoccales
Methanogens from the Zoige Wetland of the Tibetan Plateau
Authors: Yun Juanli , Du Wenbin
Published: June 2021

Wetlands in the Tibetan Plateau play a crucial role in global carbon cycling. Here, we report the metagenome-assembled genomes (MAGs) of two hydrogen-dependent methanogens from the Zoige wetland of the Tibetan Plateau. The novel species belong to
Methanomassiliicoccales
, the seventh euryarchaeal methanogenic order.
Metagenome-Assembled Genome Sequences of Novel Prokaryotic Species from the Mercury-Contaminated East Fork Poplar Creek, Oak Ridge, Tennessee, USA
Authors: Kim Minjae , Wilpiszeski Regina L. , Wells Michael , Wymore Ann M. , Gionfriddo Caitlin M. , Brooks Scott C. , Podar Mircea , Elias Dwayne A.
Published: June 2021

We sequenced two metagenomes of sediments from the East Fork Poplar Creek in the Oak Ridge Reservation (Oak Ridge, TN), a natural stream that has been contaminated with Hg from upstream sources, and we reconstructed 28 metagenome-assembled genomes of novel prokaryotic species.
Complete Closed Genome Sequence of the Inulin-Utilizing Lactiplantibacillus plantarum Strain Lp900, Obtained Using a Hybrid Nanopore and Illumina Assembly
Authors: Fuhren Jori , Nijland Reindert , Wels Michiel , Boekhorst Jos , Kleerebezem Michiel
Published: June 2021

Lactiplantibacillus plantarum
is a genetically and phenotypically diverse species of lactic acid bacteria. We announce the hybrid
de novo
assembly of Oxford Nanopore Technologies and Illumina DNA sequence reads, producing a closed circular chromosome of 3,206,992 bp and six plasmids of the inulin-utilizing
L. plantarum
strain Lp900.
Draft Genome Sequences of Five Vibrio neptunius Strains Isolated from Hatcheries of Bivalve Mollusks
Authors: Galvis Fabian , Prado Susana , Barja Juan L. , Lemos Manuel L. , Balado Miguel
Published: June 2021

Vibrio neptunius
is a Gram-negative bacterium that has been shown to cause disease in marine bivalve mollusk larvae. Here, we report the draft genome sequences and annotations of five
V. neptunius
strains isolated from larvae of European oyster (
Ostrea edulis
) and Manila clam (
Ruditapes philippinarum
) at hatcheries in Galicia, northwest Spain.
Draft Genome Sequence of
Aneurinibacillus
sp. Strain BA2021, Isolated as a Contaminant of a Laboratory-Cultivated Predatory Myxobacterium
Authors: Adaikpoh Barbara I. , Dowd Scot E. , Stevens D. Cole
Published: June 2021

During laboratory cultivation of the myxobacterium
Archangium violaceum
strain Cb vi76, a reoccurring contaminant was isolated and sequenced. Comparative taxonomic analysis of the draft genome suggested the contaminant to be a novel species, currently designated
Aneurinibacillus
sp. strain BA2021, from the genus
Aneurinibacillus
, members of which are considered promising biocontrol agents.
Be Mindful of Your Metaphors about Microbes
Authors: Maccaro Jessica
Published: June 2021

Metaphors are ubiquitous in science and have important implications for how we frame our research objectives as well as how we communicate to the public. This piece focuses on the power of metaphors to shape our attitude and actions toward antimicrobial-resistant bacteria.
Impact cratering record of Sweden—A review
Authors: Holm-Alwmark* Sanna
Published: June 2021

Studies of impact structures in Sweden date back almost 60 years. They have so far resulted in the confirmation and understanding of eight impact structures and one impact-derived breccia layer, including the largest confirmed impact structure in the western part of Europe, the Siljan impact structure. Several additional structures have been proposed as impact derived, but they have to date not been confirmed.

In this contribution, I summarize the current state of knowledge about the impact cratering record of Sweden. This is an up-to-date, comprehensive review of the features of known impact structures (and impact-related deposits) in Sweden. The described impact structures formed over a time period spanning from the Cambrian to the Cretaceous, and the preservation of several small (~1–2 km in diameter) Paleozoic impact structures indicates that the conditions securing their protection were close to optimal, with formation in a shallow epicontinental sea and rapid cover by protective sediments followed by a regional geologic evolution permitting their preservation. The generally well-preserved state of some of these crater structures contradicts the general assumption that such small impact structures can only be preserved for approximately a couple of thousand to a few million years.

The Lockne-Målingen, Tvären, Granby, and Hummeln impact structures all have ages that place their formation in a period of proposed increased cratering rate on Earth following the breakup event of the L-chondrite parent body in the asteroid belt. However, to date, evidence other than a temporal correlation is missing for all of these structures except for Lockne (and Målingen), which has been shown to have formed by the impact of an L-chondritic body.
The Cleanskin impact structure, Northern Territory and Queensland, Australia: A reconnaissance study
Authors: Kenkmann* T. , Haines P.W. , Sweet† I.P. , Mitchell K.
Published: June 2021

We report on the Cleanskin structure (18°10′00″S, 137°56′30″E), situated at the border between the Northern Territory and Queensland, Australia, and present results of preliminary geological fieldwork, microscopic analyses, and remote sensing. The Cleanskin structure is an eroded complex impact structure of ~15 km apparent diameter with a polygonal outline caused by two preexisting regional fault sets. The structure has a central uplift of ~6 km diameter surrounded by a rather shallow ring syncline. Based on stratigraphy, the uplift in the center may not exceed ~1000 m. The documentation of planar deformation features (PDFs), planar fractures (PFs), and feather features (FFs) in quartz grains from sandstone members of the Mesoproterozoic Constance Sandstone confirms the impact origin of the Cleanskin structure, as proposed earlier. The crater was most likely eroded before the Cambrian and later became buried beneath Cretaceous strata. We infer a late Mesoproterozoic to Neoproterozoic age of the impact event. In this chapter, the Cleanskin structure is compared with other midsized crater structures on Earth. Those with sandstone-dominated targets show structural similarities to the Cleanskin structure.
Sedimentation across the Paraburdoo spherule layer: Implications for the Neoarchean Earth system
Authors: Souders* Katrina S. , Davatzes* Alexandra K. , Ziegler* Brady A. , Goderis Steven , Déhais Thomas , Claeys Philippe
Published: June 2021

Large bolide impacts in the Phanerozoic produced global change identifiable in the postimpact sediments. Aside from a few isolated examples, however, evidence of postimpact change associated with Precambrian impacts is sparse. This study used the Neoarchean Paraburdoo spherule layer as a case study to search for impact-induced change in the sediments above the spherule layer. We found possible minor sedimentary changes that may have been due to either a disturbance by bottom currents or changing diagenetic conditions. Contrary to the trends found with several post–Great Oxidation Event large bolide impacts, we found no evidence of shifts in tectonic regime, sediment weathering and deposition, or paleoenvironment induced by the Paraburdoo spherule layer impact, for which the impactor is estimated to have been approximately three times larger than the Cretaceous–Paleogene bolide. This lack of a clear signal of climatic shift may be due to one or more mechanisms. Either the Paraburdoo spherule layer’s deposition in several-hundred-meter-deep water within the Hamersley Basin of Western Australia was too deep to accumulate and record observable changes, or the Neoarchean’s high-CO2 atmospheric composition acted as a threshold below which the introduction of more impact-produced gases would not have produced the expected climatic and weathering changes. We also report minor traces of elevated iron and arsenic concentrations in the sediments immediately above the Paraburdoo spherule layer, consistent with trends observed above other distal impact deposits, as well as distinctive layers of hematite nodules bracketing the spherule layer. These geochemical changes may record ocean overturn of the Neoarchean stratified water column, which brought slightly oxygenated waters to depth, consistent with the observation of tsunami deposits in shallower impact deposits and/or heating of the global oceans by tens to hundreds of degrees Celsius in the wake of the Paraburdoo spherule layer impact. Either or both of these mechanisms in addition to impact-induced shallow-water ocean evaporation may also have caused a massive die-off of microbes, which also would have produced a postimpact increase in iron and arsenic concentrations.
Prospective oversight and approval of assisted dying cases in Victoria, Australia: a qualitative study of doctors’ perspectives
Authors: White Ben P , Willmott Lindy , Sellars Marcus , Yates Patsy
Published: June 2021

Background

Assisted dying (AD) is increasingly becoming lawful internationally. While all AD models have oversight mechanisms, Victoria, Australia is rare in requiring formal approval before AD is permitted. Other jurisdictions are now enacting or implementing prospective approval models yet little is known about their operation. This paper reports the first empirical research internationally analysing the operation of a prospective approval model.

Methods

This qualitative study recruited doctors involved in providing lawful AD during the first year of the Victorian AD system. Recruitment occurred through the mandatory training doctors providing AD must undertake. Semistructured interviews were undertaken predominantly through Zoom conferencing, transcribed and thematically analysed.

Results

32 doctors from diverse specialties (including general practice) and diverse AD experiences were interviewed. Six themes were identified: (1) The primary gatekeeping to AD in practice was by the administrative Secretariat of the oversight body, the Voluntary Assisted Dying Review Board, and not the government department who issues the final ‘permit’; this may not have been intended by parliament. (2) The prospective oversight and approval process was bureaucratic and (3) the mandatory online system to manage AD was a barrier. (4) These factors caused unnecessary delays which (5) impeded AD for very sick patients. (6) However, this prospective process protected doctors and ensured system safety.

Conclusions

Potential barriers to accessing AD posed by prospective approval should be evaluated carefully by jurisdictions implementing or considering such a model. Attention is needed not only to law but to system design and how AD is implemented in practice.
Artificial light improves size selection for northern shrimp (Pandalus borealis) in trawls
Authors: Ingólfsson Ólafur Arnar , Jørgensen Terje , Sistiaga Manu , Kvalvik Liz
Published: June 2021

Size selection in the northern shrimp (Pandalus borealis) trawl fisheries is a widely studied topic. While the focus has largely been on codend and grid selectivity, studies have shown the importance of other design changes and the application of artificial light to evoke behavioural responses. LED lights of three different colours — green (∼470–580 nm), white (∼425–750 nm) and red (∼580–670 nm) — were mounted in the belly section of a shrimp trawl to investigate their influence on the overall selectivity of the trawl. The study was conducted using a twin-trawl setup, one with light and the other without light. For catch-comparison analysis, a polynomial regression with random effects was applied. The number of valid hauls with green, white and red lights were eleven, eight, and nine, respectively. All lights tested significantly affected the length-dependent retention of shrimp. Green light had the greatest effect, red the least. Significant loss was observed for shrimp below 17.5 mm carapace length (CL) for green light, 19.5 mm CL for white and 20.8 mm CL for red light.