bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of the enzyme-linked immunosorbent assay to detect serum antibody responses of volunteers who received attenuated influenza A virus vaccines
Authors: Murphy B R , Tierney E L , Barbour B A , Yolken R H , Alling D W , Holley H P , Mayner R E , Chanock R M
Published: June 2021

Sera from volunteers who received live influenza A wild-type or ts recombinant virus were tested by hemagglutination inhibition (HI) assay, neuraminidase inhibition (NI) assay, and the enzyme-linked immunosorbent assay (ELISA) to determine which assay system was the most sensitive in detecting an immunological response to infection. The ELISA was performed with inactivated whole virus antigen, and the optical density at each of five serial twofold dilutions of pre- and postimmunization sera was measured. The difference in the amount of ELISA antibody in pre- and postinoculation serum specimens was taken to be proportional to the area between the respective titration curves. The ELISA was more sensitive than the HI or NI test in detecting a seroresponse in volunteers infected with A/Hong Kong/123/77 (H1N1), A/New Jersey/8/76 (Hswine N1), or A/Alaska/6/77 (H3N2) ts recombinant virus. These results suggest that the ELISA should be used to determine the frequency of infection with attenuated viruses as well as the 50% human infectious dose of candidate live influenza A vaccine viruses.
Interaction of
Streptococcus mutans
Glucosyltransferases with Teichoic Acids
Authors: Kuramitsu H. K. , Wondrack L. , McGuinness M.
Published: June 2021

The
Streptococcus mutans
GS5 glucosyltransferase activities (both water-soluble and -insoluble glucan-synthesizing fractions) were inhibited by purified lipoteichoic acid. In vitro sucrose-dependent colonization of smooth surfaces by strain GS5 was also markedly reduced in the presence of the amphipathic molecules. The inhibition of soluble glucan synthesis by lipoteichoic acid appeared to be competitive with respect to both sucrose and primer dextran T10. These inhibitory effects were dependent on the presence of the fatty acid components of lipoteichoic acid since deacylated lipoteichoic acids did not inhibit glucosyltransferase activity. However, the deacylated molecules did interact with the enzymes since deacylated lipoteichoic acid partially protected the enzyme activity against heat inactivation and also induced the formation of high-molecular-weight enzyme complexes from the soluble glucan-synthesizing fraction. The presence of teichoic acid in high-molecular-weight aggregates of glucosyltransferase isolated from the culture fluids of strain GS5 was suggested by the detection of polyglycerophosphate in these fractions. In addition to strain GS5, two other organisms containing polyglycerophosphate teichoic acids,
Lactobacillus casei
and
Lactobacillus fermentum
, were demonstrated to bind glucosyltransferase activity. These results are discussed relative to the potential role of teichoic acid-glucosyltransferase interactions in enzyme binding to the cell surface of
S. mutans
and the formation of high-molecular-weight enzyme aggregates in the culture fluids of the organism.
ColV Plasmid-Mediated, Colicin V-Independent Iron Uptake System of Invasive Strains of
Escherichia coli
Authors: Williams Peter H. , Warner Philip J.
Published: June 2021

Evidence is presented that ColV plasmid-mediated iron uptake, an important component of the virulence of invasive strains of
Escherichia coli
, is independent of colicin V synthesis and activity. A mutant of
E. coli
K-12 deficient in the biosynthesis of enterochelin (strain AN1937) was unable to grow on minimal agar containing the chelating agent α,α′-dipyridyl unless it was harboring the plasmid ColV-K30 (strain LG1315). Acquisition of the active plasmid-specified iron sequestering system was accompanied by marked enhancement of pathogenicity in experimental infections of mice. Mutants of strain LG1315 were isolated that were defective in iron uptake due to plasmid mutations. They were unchanged with respect to colicin production, but were significantly less virulent than the parent strain. Conversely, mutants isolated as defective in colicin V synthesis were normal for the plasmid-coded iron uptake mechanism and showed the same lethality for infected mice as did strain LG1315. Furthermore, mutations in strain AN1937 which render it resistant or tolerant to the bactericidal action of colicin V did not influence the uptake of iron into plasmid-carrying strains. Cross-feeding tests involving plasmid mutants defective in iron uptake identified two plasmid-specified components of the system, an extracellular iron-chelating compound and a nondiffusible product allowing transport of iron across the bacterial cell membrane.
Characterization of the Strain-Specific and Common Surface Antigens of
Mycoplasma arginini
Authors: Alexander Angelia G. , Kenny George E.
Published: June 2021

A combination of quantitative immunoelectrophoresis and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis was used to determine location and molecular weights of surface membrane antigens of four strains of
Mycoplasma arginini.
Two major surface antigens were identified for
M. arginini
by absorption of antiserum with whole cells: one surface antigen was strain specific, electrophoretically fast, and prominently located on the surface, whereas the other surface antigen was common to the four strains and of intermediate electrophoretic mobility. Three of the four strains of
M. arginini
(G-230, 23243, and 27389) possessed immunologically strain-specific antigens which did not cross-react, whereas the leonis strain lacked an immunologically detectable unique surface antigen. A monospecific antiserum prepared against immune precipitates of the strain-specific antigen of strain G-230 detected three polypeptides of 74,000, 44,000, and 17,000 daltons in SDS-polyacrylamide gels of membrane preparations. All four strains shared the common surface antigen which appeared considerably more hydrophobic than the strain-specific surface antigen because it could only be demonstrated by charge-shift immunoelectrophoretic conditions (addition of deoxycholate to the nonionic detergent). Monospecific antiserum to the common antigen of strain G-230 reacted with all four
M. arginini
strains, but did not react with two other arginine-utilizing species, and recognized three polypeptides of 40,000, 29,000, and 20,000 daltons in membranes of strain G-230. Whereas the common surface antigen is a likely target for conventional serological reactions used for identification of the species
M. arginini
, strain-specific antigen cannot fulfill this role but must participate in other surface reactions.
Virulence of
Yersinia enterocolitica
Determined by Lethality in Mongolian Gerbils and by the Serény Test
Authors: Schiemann D. A. , Devenish J. A.
Published: June 2021

Virulence of human and environmental strains of
Yersinia enterocolitica
was evaluated by lethality in Mongolian gerbils and by the Serény test. The inducement of conjunctivitis in guinea pigs and lethality in gerbils after intraperitoneal administration was restricted to a few serotypes of
Y. enterocolitica.
Human strains of serotype O:8 were the most virulent, whereas strains of the common human serotype O:3 and most others were essentially avirulent. One virulent strain of serotype O:8 produced fatal infections within 7 days in four of five gerbils receiving 100 cells intraperitoneally. There was no observable difference in virulence between intraperitoneal and oral routes of administration, and upon death the infecting strain was found in high numbers in heart blood, lung, liver, and spleen. Virulence in both guinea pigs and gerbils was related to the presence of VW antigen determined by a nutritional requirement for calcium.
Energy Metabolism in
Capnocytophaga ochracea
Authors: Calmes Robert , Rambicure G. W. , Gorman W. , Lillich Thomas T.
Published: June 2021

Among the microflora of the gingival sulcus are members of the genus
Capnocytophaga
which have been implicated as possible etiological agents of juvenile periodontitis and systemic infectious diseases. In this study, the pathway used by
C. ochracea
strain 25 for generating energy from glucose was investigated. When grown in a complex medium supplemented with glucose and NaHCO
3
, the major end products formed were acetate (4.6 mmol), succinate (11.0 mmol), pyruvate (4.3 mmol), and oxalacetate (3.6 mmol), and the molar growth yield was 58. Addition of yeast extract to the growth medium caused (i) an increase in acetate (9.2 mmol) and succinate (14.3 mmol), (ii) a decrease in pyruvate (0 mmol) and oxalacetate (1.1 mmol), and (iii) the molar growth yield increased to 75. Glucose was transported by a phosphoenolpyruvate:phosphotransferase system and then catabolized to phosphoenolpyruvate by enzymes of the Embden-Meyerhof-Parnas pathway. No activities were detected for the key enzymes of the Warburg-Dickens, Entner-Douderoff, or hexose phosphoketolase pathways. During growth in the yeast extract-supplemented medium, approximately 37% of the phosphoenolpyruvate carbon was converted to acetate by pyruvate kinase, a pyruvate-decarboxylating enzyme activity, and acetate kinase; the remaining 63% was converted to succinate via phosphoenolpyruvate carboxykinase, malate dehydrogenase, fumarate hydratase, and fumarate reductase.
Interactions between murine alveolar macrophages and Mycoplasma pulmonis in vitro
Authors: Davis J K , Delozier K M , Asa D K , Minion F C , Cassell G H
Published: June 2021

In comparison to syngeneic fibroblasts, alveolar macrophages collected from Fischer 344 rats demonstrated a significant ability to decrease the growth rate of cell-associated Mycoplasma pulmonis, even in the absence of specific actimycoplasmal antibodies. However, when exposed to thallium acetate (a cytotoxic heavy metal), macrophages supported growth of mycoplasmas almost as well as did untreated fibroblasts. This suggests an active antimycoplasmal process operative in untreated macrophages. In contrast, mouse alveolar macrophages were not capable of exerting an antimycoplasmal effect unless rabbit anti-M. pulmonis antibodies were present. Paradoxically, mouse anti-M. pulmonis antibodies did not promote this effect.
Lectin-Mediated Induction of Human Neutrophil Chemotaxis, Chemokinesis, and Cap Formation
Authors: Kuehn Cynthia , Van Epps Dennis E.
Published: June 2021

Six lectins, including concanavalin A, phytohemagglutinin P, castor bean I, wheat germ agglutinin, peanut agglutinin, and pokeweed mitogen, were studied for their ability to stimulate human neutrophil locomotion and cap formation. Five of these lectins with known monosaccharide specificities, including concanavalin A, phytohemagglutinin, P, castor bean I, wheat germ agglutinin, and peanut agglutinin, were found to stimulate human neutrophil migration in a modified Boyden assay. Pokeweed mitogen showed negligible activity in the locomotion assay as compared with other lectins. Tests were performed to determine if the observed neutrophil migration in response to lectins was directional, and it was found that concanavalin A, phytohemagglutinin P, and peanut agglutinin were both chemokinetic and chemotactic, whereas castor bean I was only chemokinetic. Wheat germ agglutinin could not be declared chemotactic or chemokinetic due to its tendency to agglutinate neutrophils. Studies with fluoresceinated lectins demonstrated that lectins which stimulate neutrophil migration also bind to neutrophil surfaces. Preincubation with specific monosaccharide ligands blocked both stimulated locomotion and fluorescence, suggesting that an available lectin-binding site was required both for lectin binding and the stimulation of migration. Additional experiments indicated that fluoresceinated concanavalin A, phytohemagglutinin P, castor bean I, wheat germ agglutinin, and peanut agglutinin all induce cap formation on the neutrophil.
Lymphocyte Reactivity Contributes to Protection Conferred by Specific Antibody Passively Transferred to Herpes Simplex Virus-Infected Mice
Authors: Oakes John E. , Davis William B. , Taylor John A. , Weppner William A.
Published: June 2021

Passively acquired immunity to herpes simplex virus (HSV) was studied in antithymocyte serum (ATS)-treated mice and athymic nude mice to determine whether immunocompetent lymphocytes contribute to the protection observed after transfer of HSV-specific antibody to infected animals. Mice were given three intraperitoneal injections of 0.1 ml of ATS at 24-h intervals. This treatment reduced concanavalin A and lipopolysaccharide stimulation of lymphocytes harvested from these animals by 90% when compared with the stimulation of lymphocytes harvested from untreated animals. It was found that intraperitoneal injection of 0.5 ml of specific antibody 8 h after corneal HSV type 1 infection or subcutaneous HSV type 2 infection did not protect ATS-treated animals from virus infection. Specific antibody passively transferred to ATS-treated animals 8 and 120 h postinfection also failed to protect lymphocyte-depleted animals from HSV. However, ATS-treated animals were protected from HSV infection by passively acquired antibody when lymphocytes harvested from these animals regained 80% of their ability to be stimulated with concanavalin A and lipopolysaccharide. It was also found that specific antibody conferred protection to nude mice infected with HSV only if they were first reconstituted with syngeneic thymus cells 48 h before infection. The results suggest that both antiviral antibody and thymus-derived lymphocytes contribute to the recovery of HSV-infected hosts after passive immunization.
Interaction of
Pneumocystis carinii
with Host Lungs: an Ultrastructural Study
Authors: Yoneda Kokichi , Walzer Peter D.
Published: June 2021

Pneumocystis carinii
pneumonia was produced in rats by the administration of corticosteroids, low (8%) protein diet, and tetracycline in the drinking water. The rats were sacrificed at weekly intervals, and their lungs were examined by electron microscopy. For the first 6 weeks, few alterations were noted in host pulmonary tissue, except a close attachment of
P. carinii
trophozoites to the type I pneumocytes. At 7 to 8 weeks, when the infection reached the peak intensity on light microscopy, degenerative changes occurred in the type I pneumocyte, beginning with subepithelial bleb formation and followed by denudation of the basement membrane. This denuded surface appeared to be the site both of exudation of serum and tissue fluid into the alveolar space and of spread of
P. carinii
into the interstitium. There was hypertrophy of type II pneumocytes, which also occurred in uninfected control rats ingesting tetracyclines. With tapering of the corticosteroid dose,
P. carinii
was slowly cleared from the lungs, but latent infection persisted for at least 21 weeks. The host response to the corticosteroid dose tapering included increased prominence of alveolar macrophages and progressive interstitial lymphocytic infiltrate and fibrosis. Thus,
P. carinii
interacts with, and is associated with damage to, specific host cells. This interaction is important in the host-parasite relationship in this infection.
Type-common and type-specific monoclonal antibody to herpes simplex virus type 1
Authors: Pereira L , Klassen T , Baringer J R
Published: June 2021

Hybridoma cells produced by fusing mouse myeloma cells with spleen cells from mice primed with herpes simplex virus (HSV) type 1 yielded five clones producing neutralizing antibody against homologous virus. Two clones, HCl and HC2, produced antibody capable of precipitating glycoprotein C and its precursor, whereas three clones, HD1, HD2, and HD3, produced antibody capable of precipitating glycoprotein D and its precursor. Antibody produced by the HC1 and HC2 clones neutralized HSV type 1 but not HSV type 2 or HSV type 1 strain MP, which is known to lack glycoprotein C. Antibody produced by the HD1 and HD2 clones neutralized both HSV type 1 and HSV type 2, whereas antibody produced by the HD3 clone neutralized HSV type 1 but not HSV type 2. The two clones which produced antibody to glycoprotein C and the two clones which produced type-common antibody to glycoprotein D were independently derived and not clonally related inasmuch as the antibody in each pair belonged to a different subclass of immunoglobulin.
Species-dependent response to streptococcal lymphocyte mitogens in rabbits, guinea pigs, and mice
Authors: Abe Y , Alouf J E , Kurihara T , Kawashima H
Published: June 2021

Extracellular mitogen preparations from NY5 and S84 strains of streptococci induced different responses among rabbit, guinea pig, and mouse lymphocytes. Evidence of T-cell mitogenicity is presented.
Host defenses in murine malaria: failure of vaccination with formolized blood parasites to protect athymic mice from Plasmodium berghei
Authors: Murphy J R , Carter P B , MacDonald T T
Published: June 2021

The thymus dependency of immunity to erythrocytic Plasmodium berghei (NYU-2) infection generated in response to injections of Formalin-killed mixed blood parasites was shown by the demonstration that the vaccine protected immunologically intact nu/+ mice, but not their athymic nu/nu littermates.
Effect of intravenously injected killed pneumococci on leukocytes, complement, and phagocytosis in rabbits
Authors: Reed W P , Jaffee P , Albright E L , Williams R C
Published: June 2021

A pneumococcal infection may be lethal in the absence of overwhelming pulmonary involvement, and death may occur even after the organisms have been killed with antibiotics. The mechanism of death is not understood but may be related to circulating pneumococcal products. For investigating the effects of nonviable pneumococci on several host defense mechanisms, rabbits were injected intravenously with 4 X 10(8) colony-forming units of killed sonified type 13 or type 29 pneumococci. Blood was sampled periodically for the next 24 h, and the following were measured: (i) circulating levels of leukocytes; (ii) activity of the classical and alternate complement pathways; and (iii) ability of the serum to opsonize pneumococci for ingestion and killing by polymorphonuclear leukocytes. Saline-injected control rabbits showed no change in any of the functions. Nonimmune rabbits injected with either pneumococcal serotype showed progressive and profound leukopenia, no change or an increase in classical and alternate complement pathway activity, and a profound reduction in the serum-opsonizing capcity for pneumococci of the same serotype as that used in the injection. The opsonizing capacity remained normal for the other serotype. When a previously immunized animal was injected, the opsonizing capacity for the homologous organism remained intact, but leukopenia nervertheless occurred.
Long-term incorporation of tritiated adenine into deoxyribonucleic acid and ribonucleic acid by Treponema pallidum (Nichols strain)
Authors: Norris S J , Miller J N , Sykes J A
Published: June 2021

Treponema pallidum (Nichols strain), extracted in medium containing Eagle minimal essential medium 50% fresh, heat-inactivated normal rabbit serum, and 1.0 mM dithiothreitol, was incubated under 3% oxygen in the presence of tritiated nucleic acid precursors. [8-3H]adenine was incorporated with high efficiency into trichloroacetic acid-insoluble material; 2'-deoxyadenosine and uridine were incorporated in lower quantities, and thymine and thymidine were not incorporated. Incorporation of [3H]adenine was inhibited by penicillin G, mitomycin C, actinomycin D, and erythromycin, but was not affected by cycloheximide. Partial purification of nucleic acids from T. pallidum incubated with [8-3H]adenine for 36 to 72 h and subsequent treatment with ribonuclease and deoxyribonuclease revealed that 15 to 20% of the trichloroacetic acid-precipitable counts were resistant to ribonuclease but susceptible to deoxyribonuclease. A simple assay was developed in which NaOH treatment was used to distinguish incorporation into ribonucleic acid and deoxyribonucleic acid. Both ribonucleic acid and deoxyribonucleic acid synthesis continued for 6 days of incubation under 3% O2, whereas incorporation was limited to the first day of incubation in samples incubated under aerobic or anaerobic conditions. T. pallidum thus appears to be capable of significant de novo deoxyribonucleic acid and ribonucleic acid synthesis under microaerobic conditions.
K-1 Antigen Content and the Presence of an Additional Sialic Acid-Containing Antigen Among Bacteremic K-1
Escherichia coli
: Correlation with Susceptibility to Opsonophagocytosis
Authors: Stevens Paul , Chu Chung L. , Young Lowell S.
Published: June 2021

Eighty percent of blood culture isolates of
Escherichia coli
K-1 are resistant to in vitro opsonophagocytosis by normal human granulocytes and fresh serum. To determine the basis for susceptibility to phagocytosis in 20% of bacteremic K-1
E. coli
, we investigated possible quantitative and qualitative immunochemical differences in the K-1 antigen content among resistant and sensitive isolates. We prepared extracts of blood culture K-1
E. coli
by sonication and determined the K-1 polysaccharide content per dry weight of bacteria by rocket immunoelectrophoresis using cross-reactive equine anti-group B meningococcal sera. We assessed qualitative differences in the antigen content by crossed immunoelectrophoresis, using an immune globulin fraction and isolated immunoglobulin G (IgG) and IgM from the group B antisera. Three different resistant K-1 isolates contained a mean K-1 content of 48.5 ± 7.6 μg/mg ± standard deviation of dry bacteria, and three sensitive isolates contained 23.2 ± 5.6 μg/mg (
P
< 0.005). Crossed immunoelectrophoresis of extracts from both sensitive and resistant strains revealed a secondary sialic acid-containing antigen that was electrophoretically different from both the major K-1 antigen and a reference group B meningococcal antigen. This negatively charged secondary antigen was susceptible to
Clostridium perfringens
neuraminidase degradation and reacted only with IgG whereas the major K-1 antigen reacted only with IgM. This antigen was detected in the extracts of resistant isolates only at 10
10
but not at 10
9
colony-forming units per milliliter. This study demonstrates that (i) the degree of phagocytosis of bacteremic
E. coli
K-1 isolates is inversely associated with K-1 content, and (ii) more easily phagocytosed (sensitive) K-1 isolates have greater amounts of an additional sialic acid-containing antigen that appears to be unrelated to the previously described
O
acetyl K-1 antigen.
Cloning and expression of a deoxyribonucleic acid fragment that encodes for the adhesive antigen K99
Authors: van Embden J D , de Graaf F K , Schouls L M , Teppema J S
Published: June 2021

Deoxyribonucleic acid fragments of the naturally occurring conjugative K99 plasmid were cloned into vectors pBR322 and pBR325. The smallest deoxyribonucleic acid segment obtained that still expressed K99 was 4.5 megadaltons in size. With regard to the serological, adhesive, and morphological properties, no differences in the nature of the K99 antigen was observed between Escherichia coli strains carrying recombinant plasmids and those carrying pRI9901. Furthermore, the regulation of K99 expression from the recombinant plasmid deoxyribonucleic acid was similar to that from pRI9901. the low level of K99 expression in E. coli K-12 compared with natural K99-producing isolates seems to be host specific.
Role of pili in adherence of Pseudomonas aeruginosa to mammalian buccal epithelial cells
Authors: Woods D E , Straus D C , Johanson W G , Berry V K , Bass J A
Published: June 2021

Adherence of Pseudomonas aeruginosa organisms to the upper respiratory epithelium of seriously ill patients in vitro is correlated with subsequent colonization of the respiratory tract by this opportunistic pathogen. The role of pili in the attachment to epithelial cells of P. aeruginosa was studied in an in vitro system employing human buccal epithelial cells and P. aeruginosa pretreated by various means. Pretreatment of the bacteria with proteases, heat, or Formalin caused a significant decrease in adherence. A decrease when compared with controls was also noted in the adherence of P. aeruginosa organisms to buccal epithelial cells preincubated with purified pili prepared from the strain used for adherence testing; however, pili prepared from a heterologous strain failed to block adherence. Similar results were obtained in serological studies when antisera to purified pili prepared from the strain used for adherence testing decreased adherence, whereas heterologous antiserum to pili did not decrease adherence. From these results it appears that pili mediate the adherence of P. aeruginosa organisms to human buccal epithelial cells.
Role of Antibody Response in Recovery from K-Papovavirus Infection in Mice
Authors: Mokhtarian Foroozan , Shah Keerti V.
Published: June 2021

Intraperitoneal inoculation of mouse K papovavirus into infant (2 to 4 days old) Swiss albino mice produced a high-titered viremia which persisted until death due to pneumonitis on day 9 postinfection. Lungs and livers of these mice had virus-specific immunofluorescence and histological lesions. K-virus antibody was undetectable. Three- to four-week-old mice, although as susceptible to infection as infant mice, remained healthy and developed a much lower-titered viremia, a transient lung infection, and K-virus antibody on 4 to 5 days postinfection. Three- to four-week-old mice treated with cyclophosphamide developed a high-titered viremia with death 10 to 17 days postinfection and no detectable antibodies. A single intraperitoneal inoculation of K-virus antibody at 5 h or 1 day postinfection completely protected the infant Swiss albino mice. Partial protection was achieved when antibody was transferred on days 2, 3, and 4 postinoculation. Transfer of antibody to cytoxan-treated Swiss albino mice on days 3 and 6 postinfection completely portected them against K-virus-induced lesions and mortality. Transfer of normal adult BALB/c splenocytes to syngeneic infant mice before K-virus infection did not protect from death but increased survival time. Transfer of 4- to 12-day K-virus-primed adult splenocytes before infection gave a nearly 100% protection. When given before infection, the protection afforded by T-cell-enriched and B-cell-enriched adult primed splenocytes was 0 and 100%, respectively. Transfer of primed B cells on day 1 post-inoculation completely protected the infant mice. This protection decreased to 86, 57, and 56% when the primed B cells were transferred on days 2, 3, and 4 post-inoculation, respectively. These data suggest that the antibody response is of critical importance in the recovery of mice from K-virus infection. Antibody probably acts by aborting viremia, thereby preventing extensive seeding of lungs with virus.
Virus excretion and neutralizing antibody response in saliva in human cytomegalovirus infection
Authors: Tamura T , Chiba S , Chiba Y , Nakao T
Published: June 2021

The local secretory immune mechanism in infants with cytomegalovirus infection was studied by a measurement of neutralizing antibody in saliva. Neutralizing antibodies were determined by the microculture plaque assay in 65 saliva specimens including 54 samples from cytomegalovirus-infected subjects and 11 from seronegative controls. In addition, cytomegalovirus isolation from saliva or urine or both and antibody determination in serum and saliva were simultaneously performed on seven infants with cytomegalovirus excretion over long periods. Results obtained were as follows. (i) Neutralizing antibodies were detected in 41 (76%) of 54 saliva specimens obtained from infected subjects but in none of the 11 seronegative controls. (ii) Neutralizing antibodies in saliva were of low titer but persistently detectable in all but one of the seven infants. No relationship was recognized between the cessation of virus excretion and the development of neutralizing antibodies in saliva. (iii) Virus-neutralizing activity was specifically found in the immunoglobulin A fraction of pooled saliva by diethylaminoethyl cellulose chromatography.
Iron-controlled infection with Neisseria meningitidis in mice
Authors: Holbein B E
Published: June 2021

An iron-controlled infection was obtained after the intraperitoneal infection of Neisseria meningitidis strain M1011 into normal mice. The infection progressed rapidly but then disappeared in concert with the disappearance of plasma transferrin iron. Parenteral iron dextran enhanced and prolonged the infection in mice at dosages above 15 mg of Fe per kg. Studies on the distribution of iron dextran within the physiological iron pools and the importance of timing with the iron dextran addition indicated that high serum iron, available early during infection, was necessary to promote infection. High levels of iron in the reticuloendothelial system did not stimulate infection. A working hypothesis to explain the roles of iron in infection was developed: N. meningitidis obtains iron for growth from the transferrin pool, and iron dextran maintains transferrin iron levels during infection.
Facile penetration of the Staphylococcus aureus capsule by lysostaphin
Authors: King B F , Biel M L , Wilkinson B J
Published: June 2021

The ability of macromolecules to cross the capsular layer of encapsulated microorganisms and interact with their cell walls is important in considerations of the mechanisms of resistance to phagocytosis and of antigen masking in such strains. Lysostaphin was employed as a probe of the penetrability of the Staphylococcus aureus capsule. The rates of lysostaphin-induced lysis of encapsulated and unencapsulated S. aureus strains were compared. Encapsulated S. aureus strains M and Smith diffuse were lysed by lysostaphin at the same rate as their respective unencapsulated counterpart strains M variant and Smith compact. Growth of the M strain in a medium designed to enhance capsule production did not delay the onset or decrease the rate of lysis of the strain compared with organisms grown in normal medium. Cations did not selectively decrease the rate of lysis of the encapsulated strain, but inhibited the lysis of both the M and M variant strains. Peptidoglycan, the presumed lysostaphin target, isolated from both M and M variant strains was digested by lysostaphin at very similar rates. In contrast to whole cells, cations stimulated the rate of lysostaphin digestion of peptidoglycan. It is concluded that the fraction of lysostaphin active in cell lysis, believed to be a glycylglycine endopeptidase with a molecular weight of about 25,000, passes freely through the capsular layer to its target in the staphylococcal cell wall.
Galactose-containing polysaccharides from the human pathogens Sporothrix schenckii and Ceratocystis stenoceras
Authors: Mendonça-Previato L , Gorin P A , Travassos L R
Published: June 2021

Galactose-containing polysaccharides from three strains of Sporothrix schenckii and one strain of Ceratocystis stenoceras were isolated, and their structures were paritally characterized by chemical analysis and 13C-nuclear magnetic resonance spectroscopy (13C-NMR). S. schenckii polysaccharide preparations from all strains were not precipitated by Fehling solution and contained galactomannan (or a mixture of galactan and galactomannan), amylose, and minor amounts of rhamnomannan. C. stenoceras polysaccharide contained galactomannan and a smaller proportion of amylose. Conventional chemical techniques and 13C-NMR spectroscopy showed that the structures of the two preparations were closely related. The core of the galactomannan consisted principally of nonreducing end units and 2-O-, 2,6-di-O-, and perhaps 2,3-di-O-substituted alpha-D-mannopyranosyl units. The core was substituted by beta-D-galactofuranosyl chains; the units are interlinked (1 leads to 6). 13C-NMR evidence shows that the alpha-D-mannopyranosyl units are substituted in the two positions by the beta-D-galactofuranosyl residues. Galactomannans present at the cell surface of S. schenckii represent other potential fungal antigens in addition to the already recognized rhamnomannans and their peptide complexes.
Human monocyte chemotaxis: migrating cells are a subpopulation with multiple chemotaxin specificities on each cell
Authors: Falk W , Leonard E J
Published: June 2021

Only 20 to 40% of human blood monocytes were capable of responding to chemotaxins in vitro. This limit is not due to restrictions of the in vitro system, but is due to the existence of a migrating subpopulation. Over a wide range, the number of cells migrating toward a given concentration of chemotaxin was directly proportional to the number added to the chemotaxis chamber. These monocytes responded to all of the three stimuli used: human serum-derived C5a, human lymphocyte-derived chemotactic factor, and a synthetic peptide. It was possible to deactivate cells to one attractant, leaving the response to other attractants intact. This suggested that these attractants were recognized by different receptors. Several lines of evidence showed that most migrating cells had receptors for all three chemotaxins tested. Thus, if cells were assayed for migration to one attractant, no additional migration occurred when the remaining cells were assayed for migration to a different attractant. Furthermore, the same cells that had migrated toward one attractant were able to respond to other chemotaxins. We also found that a single attractant attracted as many cells as a combination of two or three attractants. Calculations from these data showed that at least 75% of the migrating monocytes have different receptors for all three attractants.
Variations in the contribution of induced interferon and adjuvanticity to the antiviral effect of different polyinosinic acid . polycytidylic acid formulations in mice infected with encephalomyocarditis virus
Authors: Stebbing N , Lindley I J , Dawson K M
Published: June 2021

Treatment of mice with polyinosinic acid . polycytidylic acid [poly(I) . poly(C)] 6 h before infection and once daily on days 1, 2, 3, 4, 7, and 10 after infection with encephalomyocarditis virus was found to confer no additional protection as compared with a single treatment 6 h before infection. When complexed with a colloid formed between carboxymethylcellulose and polylysine, poly(I) . poly(C) conferred significant additional protection with the multiple treatment regimen compared with a single treatment of 6 h before infection. The additional antiviral activity of multiple treatments could not be entirely attributed to interferon induction by the complexed form of poly(I) . poly(C), because free and complexed poly(I) . poly(C) both caused hyporesponsiveness to interferon induction after multiple treatments. However, mice protected against encephalomyocarditis virus infection by multiple treatments with the colloidal complex form of poly(I) . poly(C) showed a significant increase in resistance to reinfection, and this was attributable to adjuvant effects of the colloidal complex form of poly(I) . poly(C). The contribution of interferon induction and adjuvanticity of the poly(I) . poly(C) formulations varied with the times of treatment relative to infection, the dose of polynucleotide material, and the virus dose.
Affinity purification and characterization of protease-susceptible antigen I of Streptococcus mutans
Authors: Russell M W , Zanders E D , Bergmeier L A , Lehner T
Published: June 2021

An antigenic component (antigen I) of the cell surface of Streptococcus mutans has been purified from culture supernatants and shown to be immunologically identical to the protease-susceptible moiety of antigen I/II. Ion-exchange and gel filtration chromatography failed to yield a physicochemically homogeneous product. Immunoasbsorbent chromatography on single and tandem columns containing immobilized antibodies to antigens I/II and II yielded identical products which were homogeneous in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and which when injected into rabbits induced monospecific antisera to antigen I. This antigen consisted of approximately 70% protein. Its molecular weight was estimated as 150,000, and the isoelectric point was estimated to be 5.1. Immunofluorescence microscopy using monospecific antiserum to antigen I showed that a similar antigen was present on cells of S. mutans serotypes a, c, d, e, f, and g, but not b.
Coronavirus Porcine Epidemic Diarrhea Virus Nucleocapsid Protein Interacts with p53 To Induce Cell Cycle Arrest in S-Phase and Promotes Viral Replication
Authors: Su Mingjun , Shi Da , Xing Xiaoxu , Qi Shanshan , Yang Dan , Zhang Jiyu , Han Yuru , Zhu Qinghe , Sun Haibo , Wang Xiaoran , Wu Haoyang , Wang Meijiao , Wei Shan , Li Chunqiu , Guo Donghua , Feng Li , Sun Dongbo
Published: June 2021

Many viruses subvert the host cell cycle to create a cellular environment that promotes viral growth. PEDV, an emerging and reemerging coronavirus, has led to substantial economic loss in the global swine industry.
An Amino Acid Polymorphism within the HIV-1 Nef Dileucine Motif Functionally Uncouples Cell Surface CD4 and SERINC5 Downregulation
Authors: Mumby Mitchell J. , Johnson Aaron L. , Trothen Steven M. , Edgar Cassandra R. , Gibson Richard , Stathopulos Peter B. , Arts Eric J. , Dikeakos Jimmy D.
Published: June 2021

A contributing factor to HIV-1 persistence is evasion of the host immune response. HIV-1 uses the Nef accessory protein to evade the antiviral roles of the adaptive and intrinsic innate immune responses.
Inhibition of PARP1 Dampens Pseudorabies Virus Infection through DNA Damage-Induced Antiviral Innate Immunity
Authors: Li Guo-Li , Ding Guang-Xu , Zeng Lei , Ming Sheng-Li , Fu Peng-Fei , Wang Qi , Yang Guo-Yu , Wang Jiang , Chu Bei-Bei
Published: June 2021

Aujeszky’s disease is a notifiable infectious disease of pigs and causes economic losses worldwide in the pig industry. The causative pathogen is PRV, which is a member of the subfamily
Alphaherpesvirinae
of the family
Herpesviridae.
PRV has a wide range of hosts, such as ruminants, carnivores, and rodents.
Expanding a Learner-Centered Environment Using Group Reports and Constructivist Portfolios
Authors: BUXEDA ROSA J. , MOORE DEBORAH A.
Published: June 2021

A study was performed in the Microbial Physiology course to increase students’ self-awareness of their misconceptions, promote sound research techniques, develop written and oral communication skills, stimulate metacognition, and improve teamwork and interpersonal relationship skills. The transformation in the teaching methodology included using cooperative learning, field trips, and portfolios that targeted diverse learning styles to challenge students in creative ways and to help prepare them for future careers. The entire structure of the class was modified by introducing in-class portfolios to form a constructivist environment in which the discussion and lecture topic of the day were built on prior student knowledge. Based on evaluations, students were very pleased with the new teaching and learning process and learned more content than in the more traditional class. They also felt better able to reflect on their learning.
Successful Application of Active Learning Techniques to Introductory Microbiology
Authors: HOFFMAN ELIZABETH A.
Published: June 2021

While the traditional lecture format may be a successful way to teach microbiology to both medical and nursing students, it was not an effective means of learning for many prenursing and preprofessional students enrolled in either of the introductory microbiology courses at Ashland Community College, an open enrollment institution. The structure of both Medical Microbiology and Principles of Microbiology was redesigned to allow students to address the material in an active manner. Daily quizzes, student group discussions, scrapbooks, lab project presentations and papers, and extra credit projects were all added in order to allow students maximum exposure to the course material in a manner compatible with various methods of learning. Student knowledge, course evaluations, and student success rates have all improved with the active learning format.
Hybrid Nanopore-Illumina Genome Assembly of a Drosophila suzukii Gut Bacterial Symbiont, Gluconobacter cerinus FLW-1
Authors: Shu Runhang , Wong Adam C. N.
Published: June 2021

Gluconobacter
is a genus of acetic acid bacteria (AAB) whose members have been shown to function as insect symbionts. Here, we report the complete genome sequence of
Gluconobacter cerinus
, isolated from field-collected
Drosophila suzukii
using a hybrid assembly approach. The data provide essential insights into the metabolic functions of the symbiont to the host.
Combined Synthesis and Hydroprocessing of Hydrocarbons over Co/SiO2 + ZSM-5 + Al2O3 Catalysts Promoted by Nickel
Authors: Yakovenko R. E. , Zubkov I. N. , Bakun V. G. , Savost’yanov A. P.
Published: June 2021

The study investigates the effects of nickel introduction methods on the properties of a hybrid cobalt catalyst in a combination of Fischer–Tropsch synthesis and the hydroprocessing of the synthesized products. At 240°C, 2 MPa, and syngas WHSV 1000 h–1, the catalytic performances were compared, the products were analyzed for the hydrocarbon and fractional compositions, and the characteristics of the synthesized fuels were determined. Among the catalysts differing in nickel introduction method, the sample with a nickel-containing zeolite component prepared by ion exchange was found to have the highest hydrogenation activity, while the sample with a metal component generated by joint cobalt/nickel introduction [Co/SiO2+ Ni(i)/HZSM-5 + Al2O3] exhibited the highest isomerization activity.
Punctual Categoricity Relative to a Computable Oracle
Authors: Kalimullin I. Sh. , Melnikov A. G.
Published: June 2021

We are studying the punctual structures, i.e., the primitive recursive structures on the whole set of integers. The punctual categoricity relative to a computable oracle $$f$$ means that between any two punctual copies of a structure there is an isomorphism which togeteher with its inverse can be derived via primitive recursive schemes augmented with $$f$$. We will prove that the punctual categoricity relative to a computable oracle can hold only for finitely generated or locally finite structures. We will show that the punctual categoricity of finitely generated structures is exhaused by the computable oracles with primitive recursive graph. We also present an example of locally finite structure where the punctual categoricity is provided by a primitive recursively bounded computable oracle.
Catatonic syndrome as the presentation of encephalitis in association with COVID-19
Authors: Vazquez-Guevara Damaris , Badial-Ochoa Sandra , Caceres-Rajo Karen M , Rodriguez-Leyva Ildefonso
Published: June 2021

COVID-19 has shown different neurological manifestations even sometimes there are the initial or the main presentation.

The following case report is about a middle-aged woman who, over 3 days, developed fever, clinical neurological alterations (stupor, muteness, fixed gaze and catatonia), cerebrospinal fluid (16 lymphocytes) and an electroencephalogram (EEG) (4–6 Hz generalised activity) with characteristics of encephalitis. A serum IgG, IgM, nasopharyngeal swab PCR for SARS-CoV-2. The patient responded positively to support measures, symptomatic and corticosteroid treatment. At discharge, the patient was independent and improved considerably.

We report the presence of catatonia as a possible and atypical manifestation of encephalitis in association with COVID-19.
Galactokinase deficiency: a treatable cause of bilateral cataracts
Authors: Cordeiro Catarina , Garcia Paula , Coelho Dalila , Oliva Mónica
Published: June 2021

Congenital cataract can be caused by several systemic diseases and differential diagnosis should be done between infections, genetic or metabolic diseases. We present a case of a 12-month-old girl with bilateral nuclear cataracts that was referred for investigation. Since she did not present a family history of congenital cataracts or metabolic diseases, and her physical examination was normal, a systemic evaluation was performed. Biochemical studies disclosed abnormal galactose metabolism signs. The diagnosis of galactokinase (GALK1) deficiency was considered and the study of the GALK1 gene allowed identifying a pathogenic genetic variant and a predictably pathogenic missense mutation, previously not described. Dietary measures were imposed with a good evolution.
Acute icteric hepatitis as the first isolated symptom of COVID-19
Authors: Thiebaud Pierre-Clément , Hermand Christelle , Sobotka Jennifer , Raynal Pierre-Alexis
Published: June 2021

Patients with COVID-19 may be asymptomatic or present with extrarespiratory symptoms, such as liver injury. It has been reported that 22.5%–46.2% of patients have moderate elevation of liver enzymes. To our knowledge, acute hepatitis has never been described as an isolated symptom of COVID-19 in a previously healthy patient. We report the case of a 53-year-old patient with COVID-19 whose first clinical presentation was acute icteric hepatitis, several days before the development of others symptoms. During the pandemic, we suggest that patients with acute hepatitis be considered as COVID-19 suspects, tested and isolated.
Simultaneous occurrence of autoimmune pancreatitis and sclerosing cholangitis as immune-related adverse events of pembrolizumab
Authors: Suda Tsuyoshi , Kobayashi Masako , Kurokawa Koji , Matsushita Eiki
Published: June 2021

A 57-year-old man with lung cancer, previously treated with the programmed death-1 inhibitor pembrolizumab, was evaluated for liver injury and acute pancreatitis. Serum IgG4 levels were not elevated. Contrast-enhanced CT showed pancreatic swelling, contrast unevenness in the liver and thickening of the common bile duct and gall bladder. Magnetic resonance cholangial pancreatography revealed beads in the left intrahepatic bile duct and localised narrowing of the head and body of the central pancreatic duct. Endoscopic ultrasound-guided fine-needle and liver needle biopsy showed CD8+ and CD4+ T lymphocyte aggregates, whereas immunostaining revealed greater infiltration by CD8+ cells than CD4+ cells. IgG4-related disease was ruled out based on serum and pathological findings. The patient simultaneously presented with immune-related adverse events, autoimmune pancreatitis-like features and sclerosing cholangitis, which were ameliorated by steroid therapy. CD8+ lymphocytes were the dominant infiltrating cells in autoimmune pancreatitis and sclerosing cholangitis.