Miracle-dz/UniFAR-FTUs huggingface dataset:
Fine Structure of Rickettsia quintana Cultivated In Vitro and in the Louse

Ito, Susumu (Harvard Medical School, Boston, Mass.), and J. W. Vinson. Fine structure of Rickettsia quintana cultivated in vitro and in the louse. J. Bacteriol. 89:481–495. 1965. —Usually rod-shaped, Rickettsia quintana cells measure about 0.2 to 0.5 μ wide and up to 1.6 μ long. The rickettsiae have both an outer cell wall, about 80 A thick, and a plasma membrane, about 70 A thick, each of which is trilaminar. Occasional vesicular invaginations of the plasma membrane occur. The nuclear material, distributed in irregular zones throughout the cytoplasm, appears as a loose network of fine fibrils when postfixed with uranyl acetate and as thick strands or clumps after routine OsO4 fixation. The cytoplasm is densely packed with numerous granules, presumably ribosomes, about 150 A in diameter. Histochemical studies revealed the presence of both ribonucleic and deoxyribonucleic acids. During binary fission, a constricting furrow is formed by the cell wall and plasmalemma. No difference in fine structure was observed between R. quintana propagated on cell-free media and in the louse.
Insensitivity of Homocitrate Synthase in Extracts of Penicillium chyrosogenum to Feedback Inhibition by Lysine

We previously reported that lysine inhibits in vivo homocitrate synthesis in the lysine bradytroph, Penicillium chrysogenum L1, and that such feedback inhibition could explain the known lysine inhibition of penicillin formation. In the present study, it was found that dialyzed cell-free extracts of mutant L1 converted [1-14C]acetate to homocitrate. This homocitrate synthase activity was extremely labile but could be stabilized by high salt concentrations. The pH optimum of the reaction was 6.9, and the Km was 5.5 mM with respect to α-ketoglutarate. The reaction was also dependent upon the presence of Mg2+, adenosine 5′-triphosphate, and coenzyme A. Surprisingly, the activity in these crude extracts was not inhibited by lysine. Benzylpenicillin at a high concentration (20 mM) partially inhibited the enzyme, an effect that was enhanced by lysine. Casein hydrolysate also partially inhibited the enzyme.
Cellular Lipids of a Nocardia Grown on Propane and n-Butane

Lipid fractions of propane- and n-butane-grown nocardial cells each contain a chloroform-soluble, ether-insoluble polymer not observed previously in liquid n-alkane-grown cells. The polymer in propane-grown cells is poly-β-hydroxybutyrate. The polymer in n-butane-grown cells apparently contains unsaturation in the molecule, and is identified tentatively as a co-polymer of β-hydroxybutyric and β-hydroxybutenoic (specifically 3-hydroxy 2-butenoic) acids. The other major component of the lipid fraction consists of triglycerides containing principally palmitic and stearic acids. There seems to be little qualitative distinction in the glycerides of propane- or n-butane-grown cells. Oxidative assimilation of n-butane is described.
Comparison of Direct and Indirect Solid-Phase Microradioimmunoassays for the Detection of Viral Antigens and Antiviral Antibody

Viral antigens were fixed to the surface of microtiter wells, and serial dilutions of antiviral antibody were added. The amount of antiviral antibody bound to viral antigens was determined by measuring the extent to which the antiviral antibody either inhibited the specific binding of 125I-labeled antiviral immunoglobulin G (IgG) (direct technique) or enhanced the specific binding of 125I-labeled anti-IgG (indirect technique). Immune complexes composed of viral antigens and antiviral antibody (human) could be detected by the binding of 125I-labeled rheumatoid factor. Specific binding was influenced by the concentration of protein in the diluents used during the different steps of the procedure. A high concentration of protein in the diluent used with the viral antigens decreased specific binding, whereas a high concentration of protein in the diluent used with 125I-labeled anti-IgG increased specific binding by decreasing nonspecific attachment of the labeled anti-IgG. Under the conditions employed, the titer of a given antiviral serum was several hundredfold greater by the indirect than by the direct technique.
Method for Isolation and Identification of Corynebacterium vaginale (Haemophilus vaginalis)

A method for the clinical isolation and recognition of Corynebacterium vaginale (Haemophilus vaginalis) is presented. Wet mount and stained characteristics of genital tract discharges, cellular and colonial morphology of the bacilli, inhibition by H2O2, lack of a catalase, and fermentation of particular carbohydrates are the determinant factors. The method enables differentiation of the species from unclassified diphtheroids common to the genitourinary tract.
Improved Isolation of Anaerobic Bacteria From the Gingival Crevice Area of Man

A roll tube technique (Hungate method) was employed in an attempt to cultivate a maximal portion of the organisms in the gingival crevice area of man. This technique achieves an anaerobic state by flushing the local environment with oxygen-free gas. Once collected, the crevicular debris was immediately placed into sterile oxygen-free test tubes which were flushed out by the oxygen-free gas. In this manner, the samples were weighed, dispersed, diluted, and cultured in roll tubes and plates. The medium for control (Brewer Jar technique) and Hungate techniques was Heart Infusion Agar fortified with 10% defibrinated horse blood. When the Hungate technique was used, the recovery of viable bacteria, as a percentage of the direct microscopic count, was significantly greater than plates incubated aerobically or utilizing the Brewer Anaerobic technique. Cultural counts by using the Hungate method averaged 41.3% for six samples when 90% nitrogen and 10% hydrogen were used, 70.4% for eight samples when 85% nitrogen, 10% hydrogen, and 5% carbon dioxide were used, and 63.4% for eight samples when 100% carbon dioxide was the gaseous atmosphere. At no time were cultural counts, by using anaerobic plates (Brewer Jar), more than 24% of the direct microscopic count. This suggests that exclusion of oxygen and the presence of carbon dioxide maximized recovery of gingival crevice bacteria.
Mycobactins: iron-chelating growth factors from mycobacteria

DISCOVERY AND EARLY HISTORY OF MYCOBACTINS . 100 PRODUCTION, EXTRACTION, AND PURIFICATION. 101 Conditions for Production of Mycobactins: Influence of Iron Deficiency. 101 ExtractionMethods. 102 Purification Procedures. 103 Mycobactins as Mixtures of Homologous Compounds: Criteria of Purit. 104 PROMOTION OF GROWTH OF MICROORGANISMS BY MYCOBACTINS. 104 Assay Methods . 104 Growth Characteristics of M. paratuberculosis in the Presence of Different Mycobactins . 104 Other Growth-Promoting Properties of Mycobactins. 105 Mycobactin Inhibitors. 105 CHEMICAL STRUCTURE. 107 Nomenclature. 107 Chemical Degradation . 107 Chemical Differences Between Mycobactins. 109 PHYSICAL AND CHEMICAL PROPERTIES OF MYCOBACTINS AND THEIR DERIVATIVES. 109 General. 109 Nuclear Magnetic Resonance (NMR) Spectra . 110 Metal Complexes. 110 Ferric complexes. 110 Aluminium and gaflium complexes . 111 Chromic complexes. 112 Dissociation of tervalent complexes under acid conditions. 112 Vanadyl complexes. 112 Copper mycobactin P . 113 BIOSYNTHESIS:. 113 N6-Hydroxylysine. 113 Hydroxy Acid Unit. 114 Aromatic Acid Unit. 114 Other Units in the Mycobactin Molecule. 114 Significance of Structural Differences Among Mycobactins Produced by Different Mycobacterial Species. 114 MYCOBACTINS IN THE TAXONOMY OF MYCOBACTERIA. 115 Occurrence. 115 Classification of Mycobacterial Strains Correlated with the Type of Mycobactin Produced. 115 Practical Methods of Identifying Mycobactins for Taxonomic Purposes. 116 BIOCHEMICAL FUNCTION OF THE MYCOBACTINS. 117 Relationship of Mycobactins to Water-Soluble Sideramines. 117 Evidence Concerning the Biochemical Function ofWater-Soluble Sideramines. 118 Iron TransportTheories. 118 Sideromycins . 118 Sideramines and Aromatic Hydroxy Acids in Bacterial Iron Uptake. 120
Genetics of Pseudomonas

INTRODUCTION . 419 AVAILABILITY OF MUTANTS IN PSEUDOMONAS 420 BACTERIOPHAGES OF PSEUDOMONAS 420 General Nature of Pseudomonas Phages 421 Lysogeny 421 Genetic Control of Lysogeny 422 Phage Conversion 422 Recombination in Pseudomonas Phages. 423 HOST-CONTROLLED MODIFICATION (HCM). 423 Nature of HCM 423 Genetic Control of HCM in P. aeruginosa 423 Gene differences between strains 423 Induced mutations affecting HCM 424 Phenotypic changes in HCM caused by growth of bacteria at 43 C. 424 Plelotropic effects of other mutations on HCM. 425 Other Types of Restriction 425 GENETIC RECOMBINATION. 426 Conjugation in P. aeruginosa 426 Nature of the Sex Factor FP 426 Transfer of Chromosome 428 HCM and Conjugation. 429 Conjugation in P. echinoides 431 Transformation . 431 Transduction in P. aeruginosa 431 Transduction in P. putida 431 Defective Transducing Phage as a Fertility Factor in P. putida. 432 GENE ARRANGEMENT IN PSEUDOMONAS 432 BIOCHEMICAL GENETICS OF PSEUDOMONAS 434 Pyrimidine Biosynthesis in P. aeruginosa. 434 Isoleucine-Valine Biosynthesis in P. aeruginosa 435 Tryptophan Biosynthesis in P. putida 435 P-Ketoadipate Pathway 435 Control of Amidase Formation in P. aeruginosa. 436 Discussion of Control Mechanis 436 MUTANTS AFFECTING RECOMBINATION 437 OTHER FEATURES OF GENETIC INTEREST. 438 Autoplaque Phenomenon 438 Bacteriocins Produced by Pseudomonas. 438 Drug Resistance 439 Radiation Sensitivity. 439 Genetics of Psychrophily 440 SUMMARY.44 LITERATURE CITED.
A Padé Approximate Model of Lithium Ion Batteries

We present a reduced order model for a lithium ion battery in which Pade approximants are used to simplify complex, transcendental, transfer functions associated with the linearized, pseudo 2-dimensional (P2D) electrochemical model of the battery. The resulting transfer functions take the form of simple, rational polynomial functions, which can be used to compute any variable at any location within a one-dimensional representation of the battery domain. Corrections for nonlinear behavior are also incorporated into the reduced model. The results obtained using the reduced model compare favorably to those from the full (nonlinear) P2D model and the computational time required to produce these results is significantly reduced. Importantly, the form of the reduced model means that variables can be evaluated at specific discrete locations within the cell domain, without the need to compute all values of the variable at all discrete locations, as is the case with the spatial discretization methods most commonly used to implement the P2D model. We show that this results in further significant time savings and enhances the suitability of the model for variety of applications.
Studies on the Cecal Microflora of Commercial Broiler Chickens

A study was made of the cecal microflora isolated from broilers (5-week-old) reared under typical commercial husbandry conditions. Three hundred and twenty-five bacterial strains (randomly isolated from colonies representing 49 to 81% of the microscopic count) were isolated from cecal digesta of six animals on a rumen fluid roll tube medium (M98-5). Seventy-seven percent of these strains consisted of strict anaerobes: gram-negative, pleomorphic cocci (5.2%), Peptostreptococcus (1.5%), gram-positive rods (36.1% as Propionibacterium acnes and Eubacterium sp.), gram-negative rods (18.6% as Bacteroides clostridiiformis, B. hypermegas and B. fragilis) and sporeforming rods (15.7% as Clostridium sp.). Two types of facultatively anaerobic bacteria (gram-positive cocci and Escherichia coli) were also isolated and constituted 17.5% of the remaining flora. The distribution of the bacterial groups isolated from six cecal samples varied considerably. Data on the growth requirements of anaerobic strains indicated that many could be cultured in a simple medium consisting of an energy source, minerals, reducing agent, Trypticase, and yeast extract (or a vitamin mixture in place of yeast extract). The growth of some of these bacteria was also enhanced by CO2 and rumen fluid. These preliminary data suggest that some of the more numerous anaerobes isolated from the chicken cecum may not require complex nutrients for growth and, in fact, may be nutritionally similar to rumen anaerobes.
Effect of Low-Roughage Diets on the Microflora and Lipid Metabolism in the Rumen

Changing the diet of five lactating cows and one nonlactating cow from high to low roughage induced milk fat depression in the lactating cows and altered the composition of the rumen microflora. While the numbers of lactic and propionic acid-producing bacteria increased, the numbers of Butyrivibrio spp. decreased. The numbers of lipolytic bacteria and the in vitro lipolytic activity of the rumen fluid were also decreased, as was the extent of hydrogenation of linoleic and linolenic acids combined in soybean oil incubated in vitro with rumen fluid. It is suggested that among the bacterial population in the rumen the vibrios, which were adversely affected by the low-roughage diets, may contribute significantly to both lipolysis and hydrogenation in the rumen.
Quality, sensory and volatile profiles of fresh‐cut big top nectarines cold stored in air or modified atmosphere packaging

Summary Solid-phase microextraction (SPME) GC-MS was used to investigate the volatile organic compound (VOC) profile of fresh-cut ‘Big Top’ nectarine samples, stored in unsealed bags (AIR) or packed in active modified atmosphere (MAP) after 8 days of cold storage. Nectarine slices were also subjected to sensory and quality analysis after harvest and at the end of the storage. MAP preserved the overall quality, the appearance and the olfactory properties of nectarine slices during storage, while AIR samples showed symptoms of dehydration and browning. Sixty VOCs were identified in total in the headspace of the fresh nectarines and cold-stored fruit slices samples. Principal component analysis performed on VOCs allowed to differentiate fresh nectarines from cold-stored samples, with lactones and terpenes mainly related to fresh samples, and ester compounds positively correlated to AIR or MAP samples. Partial least square regression models allowed to identify a pool of VOC predictors of olfactory sensory descriptors.
Antibody to Viruses Affecting Cattle in Commercial Tissue Culture Grade Fetal Calf Serum

Commercial fetal calf serum (FCS) for tissue culture use was tested for neutralizing activity against several viruses which affect cattle. Certain lots of FCS contained no neutralizing activity, whereas other lots contained neutralizing activity to several viruses. It was concluded that the neutralizing activity found in certain lots of sera was due to specific antibody and that its presence could be most easily explained by the contamination of the FCS with serum from postcolostral bovine serum. A nonantibody inhibitor to vesicular stomatitis virus was also found at low levels in most lots of serum. Because those sera which had antibody had antibody to several viruses, it was suggested that the use of the micro-serum neutralization test with a few bovine viruses which are widespread in the bovine population should be satisfactory to detect FCS which was contaminated with postcolostral bovine serum.
Stability of Bacterial Mutants in Saline

By storage in 1% NaCl, genetically characterized strains of Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa were stable for more than 1 year at 4 C. This method of preservation was more effective than maintenance of the strains in stab culture.
Ribonucleic acids from animal cells

INTRODUCTION . 262 TECHNICAL ASPECTS OF RNA BIOCHEMISTRYC. 263 Size . 263 Compositio. 263 Methylation . 263 RNA-DNA Hybridization . 264 Cell Fractionation . 264 PATTERNS OF SYNTHESIS OF ANIMAL CELL R. 264 "Rapidly Labeled RNA" and Kinetic Analysis Experimes . 264 BIOSYNTHESIS OF RlBOSOMES IN ANIMAL CELLS . 267 Ribosomal PrecursorRNA. 267 Formation and Distribution of Ribosomal Particles . 272 Ribosomal Proteins and Nucleolar Ribosomal Precursors 274 Association of Ribosomal Protein withrRNA. 276 Place of Small RNA Molecules in RibosomalMaturatiot. 276 Control of Ribosome Formation.277 PRECURSORS TO TRNA MOLECULES . 279 DNA-LIKE RNA SPECIES. 280 Definition and Distribution of DNA-like RNA 280 HnRNA: Properties and Problems.283 Use ofRNA-DNA Hybridizationz in the Study ofDNA-like RNA Species.284 CONCLUSIONS . 286 LITERATURE CITED . 287
Numerical Diagnostic Key for the Identification of Enterobacteriaceae

A numerical diagnostic key for enteric organisms is described which permits the identification of typical strains and of biochemical variants with high accuracy. Unknown strains are inoculated into a basic set of five media which permit the testing of eight biochemical reactions. The positive reactions are assigned points, and the score of a strain is added up, after which the identification of the strain is obtained from a table. In many instances, the final identification is obtained with this set of biochemical tests; and, in other instances, a small number of additional tests are required to distinguish between organisms giving the same score in the basic set of biochemical tests. The key permits an accurate, rapid, and economical differentiation of the typical and the more common atypical biotypes of enteric organisms in the clinical laboratory.
Slide Agglutination Method for the Serological Identification of Neisseria gonorrhoeae with Anti-Gonococcal Antibodies Adsorbed to Protein A-Containing Staphylococci

A rapid slide agglutination test has been developed for the identification of Neisseria gonorrhoeae that are primarily detected as oxidase-positive colonies in gonococcal cultures. The technique is based on the specific nonimmune reactivity between the Fc portion of immunoglobulin (Ig)G and staphylococcal protein A. IgG molecules adsorbed to stabilized staphylococci will thereby become oriented with their antigen-reactive sites that are directed outwards. Protein A-containing staphylococci with unabsorbed anti-gonococcal antibodies gave positive co-agglutination reactions with gonococci but also with meningococci, some Moraxella, Haemophilus, and Pseudomonas strains. These crossreactions were eliminated by absorption of the anti-gonococcal antiserum with meningococcal and Moraxella organisms prior to the coating of reagent staphylococci. In the routine culture diagnosis of N. gonorrhoeae the use of specific gonococcal reagent staphylococci gave concordant results with fermentation procedures and immunofluorescent techniques.
Transformation of Rickettsia prowazekiito Rifampin Resistance

ABSTRACT Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate intracellular parasitic bacterium that grows directly within the cytoplasm of the eucaryotic host cell. The absence of techniques for genetic manipulation hampers the study of this organism’s unique biology and pathogenic mechanisms. To establish the feasibility of genetic manipulation in this organism, we identified a specific mutation in the rickettsial rpoB gene that confers resistance to rifampin and used it to demonstrate allelic exchange in R. prowazekii. Comparison of the rpoB sequences from the rifampin-sensitive (Rifs) Madrid E strain and a rifampin-resistant (Rifr) mutant identified a single point mutation that results in an arginine-to-lysine change at position 546 of theR. prowazekii RNA polymerase β subunit. A plasmid containing this mutation and two additional silent mutations created in codons flanking the Lys-546 codon was introduced into the Rifs Madrid E strain of R. prowazekii by electroporation, and in the presence of rifampin, resistant rickettsiae were selected. Transformation, via homologous recombination, was demonstrated by DNA sequencing of PCR products containing the three mutations in the Rifrregion of rickettsial rpoB. This is the first successful demonstration of genetic transformation of Rickettsia prowazekii and represents the initial step in the establishment of a genetic system in this obligate intracellular pathogen.
Discussion

The full significance of these studies will not be realized until investigations of this nature are extended to other respiratory virus diseases. By examining viruses of varying epidemic potential and comparing such factors as infectious dose, clinical illness, virus-shedding patterns, airborne survival, etc. on a quantitative basis, a better knowledge of the underlying mechanisms of airborne transmission of virus will be gained. This information will be helpful in approaches to environmental control of respiratory disease.
Passage of Treponema pallidum Through Membrane Filters of Various Pore Sizes

The passage of Treponema pallidum through commercially available Millipore membrane filters of various pore sizes was examined. No microscopically detectable organisms passed through a filter with a pore diameter of 0.22 μm. As pore size was increased, progressively more organisms passed through. Motile organisms passed through filters to a greater extent than nonmotile ones; however, 22% of the motile and 50% of the nonmotile T. pallidum organisms did not pass through the largest pore diameter tested (14.0 μm). Filtration of T. pallidum suspensions through membrane filters may offer a way of separating the organisms from larger particles of debris which accompany their extraction from rabbit testicular syphilomas.
Psychrophilic Microorganisms from Areas Associated with the Viking Spacecraft

Microorganisms capable of growth at 7 C were enumerated and isolated from soil samples from the manufacture and assembly areas of the Viking spacecraft. Populations ranging from 4.2 × 103 to 7.7 × 106/g of soil were isolated from the 15 soil samples examined. Temperature requirements were determined, and those growing at 3 C, but not at 32 C, were designated as obligate psychrophiles in this investigation. Populations of soil bacteria, including aerobic sporeformers, ranging from 1.5 × 102 to 9.8 × 105/g were capable of growth at 3 C, but not at 32 C. Bacterial isolates were identified to major generic groups. No psychrophilic sporeformers were isolated from soil from the manufacture area, but psychrophilic sporeformers ranged from 0 to 6.1 × 103/g from soil from the assembly area.
Fate of Carbon Passing Through the Glucose Pool of Rumen Digesta

The metabolism of the free glucose pool in rumen digesta from sheep fed roughage rations was studied by adding an insignificant quantity of glucose as uniformly labeled 14C-glucose of high specific activity to in vitro incubation systems. In all experiments wherein only trace quantities of glucose were added to digesta, most of the 14C-glucose entered acetate. This was true whether label was presented either as a single dose or by continuous addition over a period of 2 hr. Digesta collected at all times after feeding either once daily or at hourly intervals gave similar glucose dissimilation patterns. If, however, a relatively large quantity of carrier glucose was added together with the tracer, the 14C-acetate: 14C-propionate ratio was reduced by a factor of about 10. Physical removal of most of the protozoa from digesta generally had little effect on the dissimilation of 14C-glucose added in tracer amounts, but in one experiment there was a decreased turnover of the free glucose pool and a marked reduction in 14C entering butyrate. The paucity of 14C entering propionate when only trace amounts of glucose were added to digesta suggests that this acid was largely formed from substrates whose carbon did not equilibrate with that in free glucose or with that in intermediates of free glucose metabolism.