bluuebunny/crossref_metadata_2025 huggingface dataset:
Amplified Lymphokine Production Phenomenon Confirmed by a Macrophage 2-
d
-[
3
H]Deoxyglucose Transport Assay
Authors: McCormack Joseph G. , Moore Anne L. , Johnson Joseph E. , Philp James R.
Published: January 2020

The amplified lymphokine production phenomenon was confirmed by using an improved macrophage 2-
d
-[
3
H]deoxyglucose uptake assay as an indicator of lymphokine activity. Amplified lymphokine titers were determined in supernatants derived from tuberculin-sensitive, antigen (purified protein derivative)-stimulated, guinea pig peritoneal exudate and spleen cell suspensions after the cells were allowed to sediment into a pellicle in a conical culture tube. The deoxyglucose uptake assay, which probably measured an effect on the macrophage cell membrane, was easy to perform, and the prozone phenomenon observed with other lymphokine assay systems did not occur. The deoxyglucose uptake-enhancing moiety was stable at 56°C for 1 h and had a molecular weight of between 50,000 and 100,000, as defined by Amicon ultrafiltration. Exposure of macrophages to the lymphokine-containing supernatants did not increase macrophage deoxyglucose uptake significantly until after 9 h of incubation had elapsed. The effect on deoxyglucose uptake was to increase the
V
max
without changing the
K

m

value. Deoxyglucose uptake also involved a stereospecific carrier-facilitated transport system both in the presence and in the absence of lymphokine. The increased deoxyglucose transport induced by the lymphokine-containing supernatants was reversible. A migration inhibitory factor activity of similar molecular weight and heat stability was also present in these supernatants, but in titers lower than the titers of the deoxyglucose uptake-enhancing activity. Consequently, in the absence of a complete biochemical characterization, the two effects cannot be ascribed to the same molecular species at this time. Such a characterization, along with studies of lymphokine production and action, should be facilitated greatly by the availability of very high-titer supernatants derived by this geometric culture method.
Induction of tumor-specific cell-mediated immunity by a noninfectious type-C virus
Authors: Datta S K , McCormick K J , Trentin J J
Published: January 2020

Hamsters immunized with either noninfectious hamster type-C virus (D9) or irradiated D9 tumor cells were tested for cell-mediated immune reactivity by the macrophage migration inhibition assay. The migration of peritoneal exudate cells from immunized hamsters was significantly inhibited by either D9 virus or D9 tumor extract, but not by extract of an unrelated CELO virus-induced tumor. The virus and tumor extracts had little or no effect on the migration of peritoneal exudate cells from normal hamsters. Noninfectious D9 virus produces a cell-mediated immune response in the hamster and shares antigenicity with D9 lymphoma, which releases the virus.
Biological activity of Bordetella pertussis in lipopolysaccharide-resistant mice
Authors: Wirsing von Koenig C H , Heymer B , Hof H , Finger H , Emmerling P
Published: January 2020

Effects of Bordetella pertussis organisms, such as adjuvanticity, induction of hypersplenia, and leukocytosis as well as modification of nonspecific resistance to infection and typical morphological response of lymphatic organs, were studied in the lipopolysaccharide-resistant C3H/HeJ mouse strain. It was shown that B. pertussis exerted all of these effects in C3H/HeJ mice, although the morphological response, hypersplenia, and modification of resistance to infection with Listeria monocytogenes in such animals were less pronounced than those in lipopolysaccharide-sensitive mouse strains. This indicated that the biological activity of B. pertussis as determined in the present studies, is due partly to structural components other than lipopolysaccharide.
Immunological and biochemical relationships among flagella isolated from Legionella pneumophila serogroups 1, 2, and 3
Authors: Elliott J A , Johnson W
Published: January 2020

Flagella were isolated from virulent Legionella pneumophila serogroups 1, 2, and 3. Antiserum made against purified serogroups 1 flagellin agglutinated live, flagellated serogroups 1, 2, and 3 but not heat-killed or nonflagellated bacteria. A single line of identity was seen in immunodiffusion slides between the flagella isolated from the three serogroups and antibody to flagellin isolated from serogroups 1, 2, and 3. Indirect immunoperoxidase staining showed that antibody to flagellin isolated from serogroup 1 organisms reacted with flagella on serogroup 1, 2, and 3 bacteria. Indirect immunoperoxidase staining was also showed that antibody to flagellin isolated from serogroup 1 L. pneumophila did not react with the serogroup-specific cell surface antigen, thus demonstrating that the flagella- and the serogroup-specific antigen are separate antigens. The amino acid content of the flagella from the three serogroups was essentially the same, with aspartate, glutamate, alanine, and threonine comprising 41% of the total. Thirty-five percent of the amino acids were hydrophobic, and there were not detectable amounts of cysteine, tryptophan, or tyrosine.
Lysosomal Enzyme Content of Kupffer and Endothelial Liver Cells Isolated from Germfree and Clean Conventional Rats
Authors: Knook Dick L. , Barkway Chris , Sleyster Elisabeth C.
Published: January 2020

Rats kept under germfree conditions showed lower specific lysosomal enzyme activities in liver endothelial cells, but not in Kupffer cells.
Bactericidal activity in fractionated granule contents from human polymorphonuclear leukocytes: studies with leukocytes from normal individuals
Authors: Modrzakowski M C , Goodrum K J , Spitznagel J K
Published: January 2020

Sephadex G-100 chromatographic fractions of granule extracts from normal human polymorphonuclear leukocytes, exhibiting differences from fractions previously obtained from leukemic polymorphonuclear leukocytes, possessed cationic proteins with distinct bactericidal activity against cell wall mutants of Salmonella typhimurium LT2.
Promotion of the translocation of enteric bacteria from the gastrointestinal tracts of mice by oral treatment with penicillin, clindamycin, or metronidazole
Authors: Berg R D
Published: January 2020

Specific pathogen-free mice were treated orally with antibiotics to determine whether the resulting disruption of the normal flora ecology would allow certain gram-negative enteric bacteria to overpopulate the ceca, thereby promoting the translocation of these bacteria from the gastrointestinal tract. The mice were treated orally with penicillin, clindamycin, or metronidazole for 4 days, and then the antibiotic was discontinued. The mice were tested at various intervals for viable enteric bacilli translocating from the gastrointestinal tract to the mesenteric lymph nodes. Penicillin treatment decreased the total anaerobe population levels in the ceca an average of 1,000-fold, whereas clindamycin treatment decreased these anaerobe levels only 10-fold, and metronidazole treatment slightly increased the anaerobe levels. Penicillin or metronidazole treatment slightly increased the anaerobe levels. Penicillin or metronidazole treatment increased the enteric bacilli populations in the ceca an average of 1,000-fold, whereas clindamycin treatment increased the enteric bacilli populations 100,000-fold. The peak incidence of translocation of the enteric bacilli to the mesenteric lymph nodes averaged 100% after penicillin treatment, 97% after clindamycin treatment, and 62% after metronidazole treatment. Thus, oral treatment of mice with penicillin, clindamycin, or metronidazole for only 4 days disrupts the normal flora ecology, allowing an overgrowth in the ceca of the gram-negative enteric bacilli and promoting their translocation to the mesenteric lymph nodes.
Accelerated lesion development in experimental syphilis
Authors: Fitzgerald T J
Published: January 2020

In experimental syphilis, lesion development changes when different numbers of treponemes are injected. Lesions at sites inoculated with lower concentrations frequently exhibit delayed incubation periods, less tissue degradation, and more rapid healing. In this report I describe an unusual finding, namely, that accelerated rather than delayed incubation period occurred after intradermal inoculation of different dosages of Treponema pallidum. When rabbits were injected with only one inoculum containing 10(6), 10(5), 10(4), or 10(3) treponemes per rabbit, the corresponding incubation periods were 4.2, 7.5, 11.0 and 15.3 days, respectively. When each rabbit was injected with all four inocula on the back, the incubation periods were shortened to 3.9, 6.0, 7.0 and 8.9 days, respectively. More pronounced differences were observed with more divergent ranges of treponemal inocula. I discuss these findings in terms of the histopathology of syphilitic lesions.
Oxidant-mediated damage of Leishmania donovani promastigotes
Authors: Reiner N E , Kazura J W
Published: January 2020

Dissemination of Leishmania within the host is related to parasites undergoing unchecked proliferation. We therefore studied the effects of oxidant generating systems on promastigote multiplication by (i) direct determinations of organism proliferation and (ii) the incorporation of [3H]uracil into promastigote nucleoprotein. These two parameters correlated closely as measures of organism replication as demonstrated by parallel suppression of them by the protein synthesis inhibitors puromycin and cycloheximide and the nucleic acid synthesis inhibitors actinomycin D and mitomycin C. Promastigotes showed dose-related susceptibility to reagent and generated hydrogen peroxide (H2O2) as reflected in quantitatively similar decreases in multiplication and [3H]uracil incorporation. These effects were specific for H2O2 as catalase abrogated the dimunition in multiplication. The generation of superoxide anion by acetaldehyde-xanthine oxidase (10 mU/ml) did not alter promastigote replication or nucleoprotein synthesis. These results indicate that Leishmania donovani promastigotes are damaged by H2O2 and that the incorporation of [3H]uracil into promastigote nucleoprotein may be useful for studying the interaction of this parasite with host effector cells.
Effect of T-2 toxin on the bovine immune system: humoral factors
Authors: Mann D D , Buening G M , Hook B S , Osweiler G D
Published: January 2020

The effect of a Fusarium metabolite, T-2 toxin, on the bovine humoral immune system was explored during high-level, chronic administration. T-2 toxin administered to calves for 43 days at the rate of 0.6 mg/kg per day was associated with alterations of serum protein fractions, immunoglobulin levels, and C3 levels. Significant reductions in the levels of alpha, beta 1, beta 2, and gamma globulins, but not albumin, occurred after T-2 toxin administration. Likewise, a decline in C3 and serum immunoglobulin levels were evident. The levels of immunoglobulin M and immunoglobulin A, but not immunoglobulin G, in toxin-treated calves were significantly lower than control levels.
Requirement for an additional serum factor essential for the antibody-independent activation of the classical complement sequence by Gram-negative bacteria
Authors: Clas F , Loos M
Published: January 2020

Killing of Salmonella minnesota and Salmonella typhimurium S and R strains in serum of nonimmune humans and guinea pigs was drastically reduced in the selective absence of C1q, C1r, Ca2+, C4, or C2, the components of the classical complement pathway. Binding of C1 and C1q to the S form and six different core-deficient R mutant strains became stronger the shorter the lipopolysaccharide molecule. C1 and C1q had, under physiological conditions, no affinity to the serum-resistant S forms, whereas these components were bound by the serum-sensitive R forms with high affinity. However, a mixture of the individual complement components C1-C9, which rapidly lysed sensitized erythrocytes, did not kill the serum-sensitive bacteria. Isolated C1 bound to these bacteria cleaved fluid-phase C4 but did not convert C2. C2 turnover could be detected only when serum was used as a source of C1 or C4, indicating that an additional serum component is necessary for the antibody-independent bactericidal effect. Functional tests indicated that this factor is a euglobulin which mediates binding of C4 to the bacteria even in the absence of C1 or after treatment with EDTA. Binding of C4 followed by the generation of C4b sites as acceptors for C2 was a prerequisite for the killing of the bacteria. The factor could not be replaced by immunoglobulin G or immunoglobulin M, nor was it blocked by preincubation with anti-immunoglobulin G or anti-immunoglobulin M.
T and B lymphocyte function in response to a protein-free diet
Authors: Carlomagno M A , Alito A E , Almiron D I , Gimeno A
Published: January 2020

Groups of female adult rats were fed either isocaloric protein-free or 18% protein diets for various intervals. Four days before sacrifice, the animals were immunized either with sheep erythrocytes or with a trinitrophenyl-lipopolysaccharide (TNP-LPS) conjugate. Spleen lymphoid cell populations, spleen plaque-forming cells, and serum hemolysins were measured. A persistent diminution, proportional to the duration of protein deprivation, was observed in all parameters studied after immunization with the T-dependent antigen, sheep erythrocytes. The immune dysfunction was more pronounced for hemolysin titers, which became undetectable after 15 days of protein-free diet. The response of the protein-free group to the T-independent antigen (TNP-LPS) after 15 days of diet was only 34% of the control. When a T-cell lymphokine, macrophage migration inhibitory factor, was measured, a normal response was observed in the protein-free group. Feeding a normal diet rapidly restored the spleen plaque-forming cell populations to 60% of normal after 4 days and to 100% after 6 days. Protein starvation influenced the production of antibodies more than it did the number of antibody-forming cells. The nutritional impairment of immunoglobulin synthesis appears to be reversible.
Modulation of Mitogen-Induced Proliferation of Autologous Peripheral Blood Lymphocytes by Human Alveolar Macrophages
Authors: Yeager Henry , Sweeney Jan A. , Herscowitz Herbert B. , Barsoum Ibrahim S. , Kagan Elliott
Published: January 2020

Experiments were carried out to determine the effect of cocultivation of T-cell-enriched human peripheral blood lymphocytes with autologous alveolar macrophages on mitogen-induced proliferation as determined by [
3
H]thymidine uptake. Cells obtained by fiberoptic bronchoscopy and saline bronchial lavage from 14 normal volunteers were enriched for macrophages by adherence in plastic dishes for 1 h in RPMI 1640 medium supplemented with 10% fetal calf serum. Nonadherent mononuclear cells were prepared from heparinized venous blood after Ficoll-Hypaque sedimentation by passage over nylon wool columns. T-cell-enriched populations were incubated with and without alveolar macrophages, either in the presence or absence of phytohemagglutinin. In these experiments, the number of lymphocytes was held constant (10
5
per well), while the number of alveolar macrophages was varied (0.1 × 10
5
to 4.0 × 10
5
per well). Alveolar macrophages generally tended to stimulate phytohemagglutinin-induced lymphoproliferation at lymphocyte/macrophage ratios of 10:1 but consistently and significantly suppressed proliferation at ratios which approach those usually observed in recovered human bronchial lavage fluid, namely, 1:4. The suppressive effect of alveolar macrophages was observed as early as 48 h after culture initiation, while the magnitude of suppression increased with time. Suppression did not appear to be due to alteration in lymphocyte viability, nor was it sensitive to indomethacin. These results indicate that human alveolar macrophages can modulate the in vitro proliferative response of autologous peripheral blood lymphocytes. This observation may have relevance to interactions between alveolar macrophages and bronchial lymphocytes in the human lung in vivo.
Purification of TR-b, a Reiter treponeme protein antigen precipitating with antibodies in human syphilitic sera
Authors: Petersen C S , Pedersen N S , Axelsen N H
Published: January 2020

TR-b is a Reiter treponeme antigen, cross-reacting with an antigen in Treponema pallidum (Nichols pathogenic strain). Sera from patients with secondary syphilis contain precipitating antibodies against TR-b. The isolation of TR-b from a bacterial sonic extract is described here. It involved five fractionation steps: anion-exchange chromatography (DE-52 Whatman), gel filtration (Ac-A-22 Ultrogel), and affinity chromatography on phenyl-Sepharose CL 4B, iminodiacetic acid-Sepharose CL 4B, and lysine-Sepharose 4B, respectively. The purified TR-b was enriched 199 times compared with the starting material, and the recovery was 12%. TR-b was shown to be a protein; it did not bind to a series of lectins, and by gel filtration and polyacrylamide gel electrophoresis, the molecular weight was determined to be 610,000 to 630,000. It was found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be composed of identical 70,000-dalton subunits. The isolated TR-b was immunologically pure when tested in crossed immunoelectrophoresis against polyspecific anti-Reiter immunoglobulin. The purified TR-b antigen was used for the production of a monospecific rabbit antiserum, giving strong fluorescence with both the Reiter treponeme and T. pallidum in an indirect immunofluorescence test.
Detection of fibrils associated with Rickettsia rickettsii
Authors: Todd W J , Burgdorfer W , Wray G P
Published: January 2020

The ultrastructural appearance of the "halozone" formed at the interface between the spotted fever agent Rickettsia rickettsii and the cytoplasm of persistently infected cultured vole cells (Microtus pennsylvanicus) was studied by transmission electron microscopy. In sections of epoxy-embedded specimens stained with uranyl acetate and lead citrate, the halozone appeared clear and devoid of ultrastructural features. However, when unembedded preparations of whole infected cells were examined at 1,000 kV, fine structural features were observed within the halozone. These features, associated with the rickettsial outer membrane, were more clearly detectable when the infected cells were extracted with the detergent Triton X-100 before fixation. Under such conditions, long extensions of the rickettsial outer membrane, microfilament-like structures attached to that membrane, and extensive attachments between adjacent rickettsiae were seen. The fine structural features within the rickettsial halozone were also seen at 75 kV when unembedded sections were prepared from polyethylene glycol-embedded specimens. Thus, epoxy-embedding medium obscures the fine structural features within the halozone surrounding the rickettsiae in infected cells.
Analysis of macrophage interactions with cryopreserved amastigotes of Leishmania tropica
Authors: Hoover D L , Nacy C A
Published: January 2020

Amastigotes of Leishmania tropica were harvested from infected footpads of BALB/cJ mice and cryopreserved, using a controlled-rate freezer. This technique produced inocula with reproducible viability and infectivity for peritoneal macrophages from C3H/HeN mice. Cryopreserved amastigotes, stored for up to 17 weeks in a liquid nitrogen freezer, were similar to freshly harvested parasites in susceptibility to lymphokine-induced intracellular killing. Interactions of cryopreserved parasites with macrophages were best evaluated at 72 h, since macrophages preferentially ingested viable amastigotes and rapidly cleared ingested nonviable parasites.
A type-specific antigen of Eikenella corrodens is the major outer membrane protein
Authors: Maliszewski C R , Shuster C W , Badger S J
Published: January 2020

Eikenella corrodens released antigenic material in the form of outer membrane fragments during growth. A culture filtrate antigen (AgA) from three strains reacted with antisera to whole bacteria with serotype specificity. A monoclonal antibody to the AgA of strain 1073 reacted with only 2 of 12 strains tested by enzyme-linked immunosorbent assay, immunofluorescence assay, and immunoelectrophoresis assay. The antigenic reactivity was resistant to boiling and to pronase and trypsin treatments. AgA was isolated from an outer membrane preparation after boiling in sodium dodecyl sulfate, radioiodinating the proteins, and precipitating AgA specifically with monoclonal antibody. A single protein band corresponding to the major outer membrane protein of E. corrodens was observed by autoradiography of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the immunoprecipitate. AgA had a molecular weight of 42,000, and its amino acid content resembled those reported for major outer membrane proteins with similar molecular weights from two other gram-negative organisms.
Depressed in vitro and in vivo antibody response and adoptive transfer of delayed hypersensitivity to myoglobin with spleen cells of mice chronically infected with Schistosoma japonicum and injected with myoglobin
Authors: Garb K S , Stavitsky A B
Published: January 2020

Spleen cells from C57BL/6J mice infected for 21 weeks with Schistosoma japonicum did not show an in vitro secondary antibody response upon challenge with sperm whale myoglobin. Mice infected for 13 weeks showed almost no in vivo secondary antibody response to this antigen. Spleen cells from mice infected for 12 to 21 weeks did not adoptively transfer delayed hypersensitivity to this antigen.
Effect of C3 depletion on experimental Pseudomonas aeruginosa ocular infection: histopathological analysis
Authors: Hazlett L D , Berk R S
Published: January 2020

The ocular histopathological response of C3-depleted and normal DBA/2J mice was compared after corneal scarification and experimental infection with topically applied Pseudomonas aeruginosa. Normal, non-C3-depleted mice were capable of mounting a vigorous polymorphonuclear leukocyte response at 24 h after bacterial challenge and eventually restored corneal clarity. In contrast, C3-depleted animals responded at 24 h to the ocular bacterial challenge with a decreased number of polymorphonuclear leukocytes migrating into the cornea. Additionally, the eyes of C3-depleted mice exhibited persistence of bacteria, cataract of the ocular lens, and loss of vision.
Protection against fatal Pseudomonas aeruginosa burn wound sepsis by immunization with lipopolysaccharide and high-molecular-weight polysaccharide
Authors: Cryz S J , Fürer E , Germanier R
Published: January 2020

A murine burn wound model was employed to evaluate the relative efficacy of purified Pseudomonas aeruginosa lipopolysaccharide (LPS) and high-molecular-weight polysaccharide as protective immunogens. LPS was found to be both highly immunogenic and protective. As little as three 0.001-microgram doses elicited good immunoglobulin M and G titers and increased the mean lethal dose more than 1,000-fold. The level of protection against a live challenge correlated with antibody titers and was found to be serotype specific. An immunizing regimen which evoked only an immunoglobulin M response was still found to offer substantial protection. Immunization with a high-molecular-weight polysaccharide was also found to be protective. However, approximately 1,000-fold more high-molecular-weight polysaccharide, as compared with LPS, was needed to protect mice to an equivalent degree. Immunization with LPS was found to promote bacterial clearance and prevent establishment of bacteremia. A multivalent LPS vaccine conferred high levels of protection (110- to 53,000-fold) against eight different challenge strains of various serotypes.
Cloning and expression of Legionella pneumophila antigens in Escherichia coli
Authors: Engleberg N C , Drutz D J , Eisenstein B I
Published: January 2020

To isolate and characterize Legionella pneumophila antigens, we constructed a genomic library of L. pneumophila serogroup 1 (strain 130b). L, pneumophila DNA fragments (2.5 to 7.5 megadaltons) obtained by partial digestion with Sau 3A endonuclease and size fractionation on a sucrose density gradient were inserted into the dephosphorylated BamHI site of vector pBR322; CaCl2-treated Escherichia coli cells of strain HB101 were transformed with hybrid plasmids. To detect expression of antigens, 2,559 ampicillin-resistant transformants were transferred to nitrocellulose paper, lysed in situ, and screened by enzyme immunoassay (EIA) with E. coli-absorbed rabbit anti-L. pneumophila sera. A total of 77 (3%) of the colonies were reactive by EIA; 31 (1.2%) were strongly reactive, and 6 were strongly reactive by EIA without colony lysis. Analysis of 29 stable, strongly reactive clones by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electroblotting showed antigenic bands in 18 clones by EIA with E. coli-absorbed antisera. Absorption of antisera with heat- and Formalin-killed L. pneumophila antigen eliminated or diminished the reactivity of the antigenic bands in representative clones. These studies confirm that several L. pneumophila antigens can be cloned and expressed in E. coli.
Flagella help Salmonella typhimurium survive within murine macrophages
Authors: Weinstein D L , Carsiotis M , Lissner C R , O'Brien A D
Published: January 2020

In this study, we evaluated how flagella enhance the pathogenicity of Salmonella typhimurium in strain C57BL/6J mice. When mice were infected orally with flagellated or nonflagellated S. typhimurium, equivalent numbers of bacteria colonized the gastrointestinal tracts of the animals, but the number of flagellated organisms increased faster once colonization began in the spleens and livers. To evaluate this differential rate of Salmonella growth, the rate of blood clearance, and the kinetics of net multiplication of salmonellae in splenic tissue after intravenous challenge, the two groups of mice were compared. We found that clearance of bacteria from the blood was the same for flagellated or nonflagellated strains. However, the number of flagellated bacteria in the spleen increased logarithmically until the death of the animals, whereas the number of nonflagellated salmonellae increased only slightly. In contrast, both flagellated and nonflagellated strains grew exponentially in the spleens of mice pretreated with silica, a macrophage toxic agent. In an in vitro macrophage assay, flagellated salmonellae survived longer than nonflagellated organisms. These results indicate that flagella either protect S. typhimurium from the intracellular killing mechanisms of murine macrophages or that flagella enhance the ability of S. typhimurium to multiply within murine macrophages.
Evaluation of the ResistancePlus MG FleXible Assay for Detection of Wild-Type and 23S rRNA-Mutated Mycoplasma genitalium Strains
Authors: Drud Suhella Tulsiani , Njuguna Peter , Ebeyan Samantha , Erskine Simon , Holm Mette , Johansson Susanne Cramer , Tan Lit Yeen , Jensen Jorgen Skov
Published: January 2020

Antibiotic resistance in
Mycoplasma genitalium
is rising globally, and resistance-guided diagnostics can facilitate targeted and timely treatment. The ResistancePlus MG FleXible (RPMG Flex) assay for the detection of
M. genitalium
and macrolide resistance-mediating mutations (MRMM) was evaluated for analytical sensitivity, specificity, reproducibility, and inhibition in the presence of interfering substances by simulating
M. genitalium
-negative pooled urine and swab matrices with
M. genitalium
cultures.
Conserved Rotavirus NSP5 and VP2 Domains Interact and Affect Viroplasm
Authors: Buttafuoco Antonino , Michaelsen Kevin , Tobler Kurt , Ackermann Mathias , Fraefel Cornel , Eichwald Catherine
Published: January 2020

Alternative treatments to combat rotavirus infection are a requirement for susceptible communities where vaccines cannot be applied. This demand is urgent for newborn infants, immunocompromised patients, adults traveling to high-risk regions, and even for the livestock industry. Aside from structural and physiological divergences among RV species studied before now, all replicate within cytosolic inclusions termed viroplasms. These inclusions are composed of viral and cellular proteins and viral RNA. Viroplasm-like structures (VLS), composed of RV protein NSP5 with either NSP2 or VP2, are models for investigating viroplasms. In this study, we identified a conserved amino acid in the VP2 protein, L124, necessary for its interaction with NSP5 and the formation of both VLSs and viroplasms. As RV vaccines cover a narrow range of viral strains, the identification of VP2 L124 residue lays the foundations for the design of drugs that specifically block NSP5-VP2 interaction as a broad-spectrum RV antiviral.
Macrophage Proresolving Mediators—the When and Where
Authors: Dalli Jesmond , Serhan Charles
Published: January 2020

Macrophages and neutrophils orchestrate acute inflammation and host defense as well as the resolution phase and return to homeostasis. In this article, we review the contribution of macrophages to local lipid mediator (LM) levels and the regulation of macrophage LM profiles by polymorphonuclear neutrophils and neutrophil-derived microparticles. We carried out LM metabololipidomics, profiling distinct phagocytes: neutrophils (PMNs), apoptotic PMNs, and macrophages. Efferocytosis increased specialized proresolving mediator (SPM) biosynthesis, including resolvin D1 (RvD1), RvD2, and RvE2, which were further elevated by PMN microparticles. In studies using deuterium-labeled precursors (d8-arachidonic acid,d5-eicosapentaenoic acid, andd5-docosahexaenoic acid), apoptotic PMNs and microparticles contributed to SPM biosynthesis during efferocytosis. Assessment of macrophage LM profiles in M2 macrophages demonstrated higher SPM levels in this macrophage subset, including maresin 1 (MaR1), and lower amounts of leukotriene B4(LTB4) and prostaglandins than in M1. Apoptotic PMN uptake by both macrophage subtypes led to modulation of their LM profiles. LTB4was downregulated in M2, whereas SPMs including lipoxin A4were increased. Conversely, uptake of apoptotic PMNs by M2 macrophages reduced (∼25%) overall LMs. MaR1 displays potent tissue-regenerative and antinociceptive actions in addition to its proresolving and anti-inflammatory actions. In addition, the MaR1 biosynthetic intermediate 13S,14S-epoxy-maresin is also bioactive, inhibiting LTB4biosynthesis and switching macrophage phenotypes from M1 to M2. Together, these results establish LM signature profiles of human phagocytes and related subpopulations. They demonstrate microparticle regulation of macrophage-specific endogenous LMs during defined stages of acute inflammation and their dynamic changes in human primary phagocytes.
Binning Singletons: Mentoring through Networking at ASM Microbe 2019
Authors: James Joseph B. , Gunn Amanda L. , Akob Denise M.
Published: January 2020

The American Society for Microbiology (ASM) national conference, Microbe, is the flagship meeting for microbiologists across the globe. The presence of roughly 10,000 attendees provides enormous opportunities for networking and learning. However, such a large meeting can be intimidating to many, especially early career scientists, students, those attending alone, and those from historically underrepresented groups.
Weak Acid Resistance A (WarA), a Novel Transcription Factor Required for Regulation of Weak-Acid Resistance and Spore-Spore Heterogeneity in Aspergillus niger
Authors: Geoghegan Ivey A. , Stratford Malcolm , Bromley Mike , Archer David B. , Avery Simon V.
Published: January 2020

Weak acids are widely used as food preservatives, as they are very effective at preventing the growth of most species of bacteria and fungi. However, some species of molds can survive and grow in the concentrations of weak acid employed in food and drink products, thereby causing spoilage with resultant risks for food security and health. Current knowledge of weak-acid resistance mechanisms in these fungi is limited, especially in comparison to that in yeasts. We characterized gene functions in the spoilage mold species
Aspergillus niger
which are important for survival and growth in the presence of weak-acid preservatives. Such identification of weak-acid resistance mechanisms in spoilage molds will help in the design of new strategies to reduce food spoilage in the future.
Biosynthesis of β-(1→5)-Galactofuranosyl Chains of Fungal-Type and
O
-Mannose-Type Galactomannans within the Invasive Pathogen Aspergillus fumigatus
Authors: Chihara Yuria , Tanaka Yutaka , Izumi Minoru , Hagiwara Daisuke , Watanabe Akira , Takegawa Kaoru , Kamei Katsuhiko , Shibata Nobuyuki , Ohta Kazuyoshi , Oka Takuji
Published: January 2020

β-(1→5)-Galactofuranosyl residues are widely distributed in the subphylum Pezizomycotina of the phylum Ascomycota. Pezizomycotina includes many plant and animal pathogens. Although the structure of β-(1→5)-galactofuranosyl residues of galactomannans in filamentous fungi was discovered long ago, it remains unclear which enzyme is responsible for biosynthesis of this glycan. Fungal cell wall formation processes are complicated, and information concerning glycosyltransferases is essential for understanding them. In this study, we showed that GfsA and GfsC are responsible for the biosynthesis of all β-(1→5)-galactofuranosyl residues of fungal-type and
O
-mannose-type galactomannans. The data presented here indicate that β-(1→5)-galactofuranosyl residues are involved in cell growth, conidiation, polarity, and cell surface hydrophobicity. Our new understanding of β-(1→5)-galactofuranosyl residue biosynthesis provides important novel insights into the formation of the complex cell wall structure and the virulence of the members of the subphylum Pezizomycotina.
Harvesting of Prebiotic Fructooligosaccharides by Nonbeneficial Human Gut Bacteria
Authors: Wang Zhi , Tauzin Alexandra S. , Laville Elisabeth , Tedesco Pietro , Létisse Fabien , Terrapon Nicolas , Lepercq Pascale , Mercade Myriam , Potocki-Veronese Gabrielle
Published: January 2020

Prebiotics are increasingly used as food supplements, especially in infant formulas, to modify the functioning and composition of the microbiota. However, little is currently known about the mechanisms of prebiotic recognition and transport by gut bacteria, while these steps are crucial in their metabolism. In this study, we established a new strategy to profile the specificity of oligosaccharide transporters, combining microbiomics, genetic locus and strain engineering, and state-of-the art metabolomics. We revisited the transporter classification database and proposed a new way to classify these membrane proteins based on their structural and mechanistic similarities. Based on these developments, we identified and characterized, at the molecular level, a fructooligosaccharide transporting phosphotransferase system, which constitutes a biomarker of diet and gut pathology. The deciphering of this prebiotic metabolization mechanism by a nonbeneficial bacterium highlights the controversial use of prebiotics, especially in the context of chronic gut diseases.
Human Papillomavirus 16 E6 and E7 Synergistically Repress Innate Immune Gene Transcription
Authors: James Claire D. , Fontan Christian T. , Otoa Raymonde , Das Dipon , Prabhakar Apurva T. , Wang Xu , Bristol Molly L. , Morgan Iain M.
Published: January 2020

The role of human papillomavirus 16 (HPV16) in human cancers is well established; however, to date there are no antiviral therapeutics that are available for combatting these cancers. To identify such targets, we must enhance the understanding of the viral life cycle. Innate immune genes (IIGs) are repressed by HPV16, and we have reported that this repression persists through to cancer. Reversal of this repression would boost the immune response to HPV16-positive tumors, an area that is becoming more important given the advances in immunotherapy. This report demonstrates that E6 and E7 synergistically repress IIG expression in the context of the entire HPV16 genome. Removal of either protein activates the expression of IIGs by HPV16. Therefore, gaining a precise understanding of how the viral oncogenes repress IIG expression represents an opportunity to reverse this repression and boost the immune response to HPV16 infections for therapeutic gain.
mSphere of Influence: Positive Research Culture Enables Excellence and Innovation
Authors: Ballou Elizabeth R.
Published: January 2020

Elizabeth Ballou works in the field of medical mycology. In this mSphere of Influence article, she reflects on how two papers by Okagaki et al. (PLoS Pathog 6:e1000953, 2010,
https://doi.org/10.1371/journal.ppat.1000953
) and Zaragoza et al. (PLoS Pathog 6:e1000945, 2010,
https://doi.org/10.1371/journal.ppat.1000945
) made an impact on her career by demonstrating an alternative to destructive publication practices.
A Middle Devonian basin-scale precious metal enrichment event across northern Yukon (Canada)
Authors: Gadd M.G. , Peter J.M. , Hnatyshin D. , Creaser R. , Gouwy S. , Fraser T.
Published: January 2020

Hyper-enriched black shale (HEBS) Ni-Mo-Zn-Pt-Pd-Au-Re mineralization is geographically widespread across the Richardson trough in northern Yukon (Canada), where it discontinuously outcrops at the regional contact between the Road River Group and overlying Canol Formation. Stratigraphic relationships indicate that the contact is Middle Devonian, but there are no precise age constraints for the HEBS. We apply Re-Os geochronology to HEBS mineralization from two localities that are 130 km apart, the Nick prospect and the Peel River showing, to date directly the age of sulfide mineralization. The Nick prospect yields an isochron age of 390.7 ± 5.1 (2σ) Ma, whereas the Peel River showing yields an isochron age of 387.5 ± 4.4 (2σ) Ma. Within error, these ages are identical and overlap with the biostratigraphically constrained age of the sedimentary host rocks, indicating that mineralization and sedimentation were coeval. Significantly, the ages of the HEBS overlap those of Middle Devonian Kačák, pumilio, and Taghanic global-scale biotic events which are characterized by eustatic sea-level rise and black shale deposition. Linkage of the Yukon HEBS to one (or more) of these bio-events indicates that sea-level rise may have been requisite to formation of basin-scale HEBS mineralization in northwestern Canada during latest Eifelian and Givetian time.
Magnetite magnetofossils record biogeochemical remanent magnetization in hydrogenetic ferromanganese crusts
Authors: Yuan Wei , Zhou Huaiyang , Yang Zhenyu , Hein James R. , Yang Qunhui
Published: January 2020

Records of natural remanent magnetization (NRM) and geomagnetic polarity reversals preserved within ferromanganese (Fe-Mn) crusts, together with the application of fine-resolution magnetostratigraphic analysis, have been successfully demonstrated. However, because Fe-bearing precipitates or minerals are thought to be either oxides and/or hydroxides precipitated from ambient oxic seawater or detrital minerals, the magnetic properties of the ferromagnetic minerals and the genetic mechanisms remain controversial; moreover, the origin of the NRM is unclear. Here, we show that nanometer-scale magnetite crystals found in Fe-Mn crusts from the Pacific Ocean and South China Sea are magnetosome fossils based on their narrow size range, chain arrangement, chemical purity, and crystallographic perfection, as indicated by transmission electron microscopy. Furthermore, our new data from rock magnetic and electron paramagnetic resonance analyses, combined with a previously reported micro-magnetostratigraphic sequence, indicate that magnetotactic bacteria and their post-mortem remains contribute to a biogeochemical remanent magnetization of Fe-Mn crusts. In addition, the results provide evidence for a previously unappreciated pathway for the biogeochemical cycling of iron in the deep ocean.
A significant acceleration of ice volume discharge preceded a major retreat of a West Antarctic paleo–ice stream
Authors: Bart Philip J. , Tulaczyk Slawek
Published: January 2020

For the period between 14.7 and 11.5 cal. (calibrated) kyr B.P, the sediment flux of Bindschadler Ice Stream (BIS; West Antarctica) averaged 1.7 × 108 m3 a−1. This implies that BIS velocity averaged 500 ± 120 m a−1. At a finer resolution, the data suggest two stages of ice stream flow. During the first 2400 ± 400 years of a grounding-zone stillstand, ice stream flow averaged 200 ± 90 m a−1. Following ice-shelf breakup at 12.3 ± 0.2 cal. kyr B.P., flow accelerated to 1350 ± 580 m a−1. The estimated ice volume discharge after breakup exceeds the balance velocity by a factor of two and implies ice mass imbalance of −40 Gt a−1 just before the grounding zone retreated >200 km. We interpret that the paleo-BIS maintained sustainable discharge throughout the grounding-zone stillstand first due to the buttressing effect of its fringing ice shelf and then later (i.e., after ice-shelf breakup) due to the stabilizing effects of grounding-zone wedge aggradation. Major paleo–ice stream retreat, shortly after the ice-shelf breakup that triggered the inferred ice flow acceleration, substantiates the current concerns about rapid, near-future retreat of major glaciers in the Amundsen Sea sector where Pine Island and Thwaites Glaciers are already experiencing ice-shelf instability and grounding-zone retreat that have triggered upstream-propagating thinning and ice acceleration.
Orogen proximal sedimentation in the Permian foreland basin
Authors: Soto-Kerans Graham M. , Stockli Daniel F. , Janson Xavier , Lawton Timothy F. , Covault Jacob A.
Published: January 2020

The sedimentary fill of peripheral foreland basins has the potential to preserve a record of the processes of ocean closure and continental collision, as well as the long-term (i.e., 107–108 yr) sediment-routing evolution associated with these processes; however, the detrital record of these deep-time tectonic processes and the sedimentary response have rarely been documented during the final stages of supercontinent assembly. The stratigraphy within the southern margin of the Delaware Basin and Marathon fold and thrust belt preserves a record of the Carboniferous–Permian Pangean continental assembly, culminating in the formation of the Delaware and Midland foreland basins of North America. Here, we use 1721 new detrital zircon (DZ) U-Pb ages from 13 stratigraphic samples within the Marathon fold and thrust belt and Glass Mountains of West Texas in order to evaluate the provenance and sediment-routing evolution of the southern, orogen-proximal region of this foreland basin system. Among these new DZ data, 85 core-rim age relationships record multi-stage crystallization related to magmatic or metamorphic events in sediment source areas, further constraining source terranes and sediment routing. Within samples, a lack of Neoproterozoic–Cambrian zircon grains in the pre-orogenic Mississippian Tesnus Formation and subsequent appearance of this zircon age group in the syn-orogenic Pennsylvanian Haymond Formation point toward initial basin inversion and the uplift and exhumation of volcanic units related to Rodinian rifting. Moreover, an upsection decrease in Grenvillian (ca. 1300–920 Ma) and an increase in Paleozoic zircons denote a progressive provenance shift from that of dominantly orogenic highland sources to that of sediment sources deeper in the Gondwanan hinterland during tectonic stabilization. Detrital zircon core-rim age relationships of ca. 1770 Ma cores with ca. 600–300 Ma rims indicate Amazonian cores with peri-Gondwanan or Pan-African rims, Grenvillian cores with ca. 580 Ma rims are correlative with Pan-African volcanism or the ca. 780–560 Ma volcanics along the rifted Laurentian margin, and Paleozoic core-rim age relationships are likely indicative of volcanic arc activity within peri-Gondwana, Coahuila, or Oaxaquia. Our results suggest dominant sediment delivery to the Marathon region from the nearby southern orogenic highland; less sediment was delivered from the axial portion of the Ouachita or Appalachian regions suggesting that this area of the basin was not affected by a transcontinental drainage. The provenance evolution of sediment provides insights into how continental collision directs the dispersal and deposition of sediment in the Permian Basin and analogous foreland basins.
Head and neck cancer in the digital age: an evaluation of mobile health applications
Authors: Fleming Jason , Jeannon Jean-Pierre
Published: January 2020

Aim

The technology of online and mobile-based symptom checkers is developing on a background of unprecedented demand for General Practioner (GP) and medical services. This study was performed to assess the performance of popular ‘artificial intelligence’ symptom checkers currently available to the public and evaluate their accuracy as a screening tool for head and neck cancer symptoms.

Method

We selected three of the most popular and previously compared mobile application (app) symptom checkers available including Babylon (London), Your.md (London) and Ada (Ada Health GmbH, Munich). A recent Pan-London Suspected Cancer Referral Guide was obtained and distilled into a list of qualifying symptoms for referral to secondary care on a 2-week wait cancer pathway. A generic patient background was devised and each symptom was passed through the selected symptom checker apps. Differential diagnoses and recommended triage times were compared.

Results

Overall a cancer diagnosis was suggested possible in the differential diagnosis in 33% of symptoms. As a screening tool, Babylon was the most accurate for including a potential cancer diagnosis in the differential diagnosis, with a sensitivity of 45% cases, Ada with 32% and Your.md 23%. Ada attempted the most diagnoses, able to provide a differential diagnosis in 95% scenarios, but was also the most risk averse triage assessor, with 55% outcomes recommending medical advice immediately or within hours.

Conclusion

The ability of modern symptom checkers to promote health awareness and self-checks is promising, but we have identified a number of areas of potential improvement. At present the sensitivity of the tested symptom checker apps remains low for head and neck cancer.