Reciprocal Tests Research Articles

Immunochemical cross-reactivity between the dissociated capsid proteins of PVY group plant viruses

Primary (4–5-week) and long-term (12-week) antisera were elicited against the pyrrolidine-dissociated capsid proteins (D-proteins) of tobacco etch virus (TEV) and potato virus Y (PVY), and subsequently used to ascertain the degree of immunochemical cross-reactivity between several PVY group viral D-proteins. Primary antisera were highly specific for homologous antigen. However, immunodiffusion and cross-absorption experiments with long-term anti-TEV D-protein and anti-PVY D-protein sera revealed pronounced cross-reactivity among the D-proteins of 14 different PVY group viruses. Furthermore, all cross-reactions involved the same antibody population except in the case of celery mosaic virus (CeMV) D-protein where but a portion of the antibody population was reactive. Spur formation in immuno-diffusion experiments was only observed among heterologous D-proteins when they were either adjacent to homologous D-protein antigen or (in an opposite direction) when compared with CeMV D-protein. Wheat streak mosaic virus dissociated protein, in contrast, was not found to be cross-reactive with PVY group D-proteins in reciprocal tests, and no cross-reactions were observed with the dissociated proteins of 6 additional viruses outside the PVY group.

Antigens of tumours induced by naturally occurring murine sarcoma virus (MSV-FBJ). I. Detection of group and type specific antigens by complement fixation.

Antigens associated with cells transformed in vivo by FBJ virus, a wild type murine sarcoma virus (MSV) complex originating from a spontaneously arising osteosarcoma in a CF1 mouse, have been partially characterized by complement fixation (CF). Using rat antisera against antigens specified by Gross leukaemia virus (GLV) the group specific (gs) antigen of C-type RNA murine tumour viruses was demonstrated in FBJ tumours as well as in GLV rat leukaemias, AKR lymphomata and sarcomata induced by MSV-H (Harvey), an MSV isolate of Friend-Moloney-Rauscher (FMR) subgroup specificity. Using mouse antisera against antigens present in FBJ cells the Gross (G) or wild type specificity of FBJ tumours was demonstrated by cross reactivity with antigens expressed on normal AKR lymphoid tissues and leukaemias. These antigens were absent from MSV-H induced sarcomata and in reciprocal tests mouse antisera to MSV-H failed to react with antigens present in FBJ tumour cells. No distinction between cellular and virion antigens expressed by FBJ cells was possible by CF although evidence for a cellular antigen with G specificity was obtained in tests using aged C57B1 antiserum containing a naturally occurring G antibody lacking significant virus neutralizing capacity. However, the likelihood that mouse FBJ antisera contain antibodies to type specific viral envelope antigens (VEA) as well as cellular antigen is discussed.

Genetic analysis of thr mutations in Salmonella typhimurium.

Previous workers divided threonine-requiring (Thr(-)) strains of Salmonella into three phenotypes with mutations in four complementation groups. The mutations were deemed to define four genes in the order thrD-C-A-B at minute zero on the Salmonella linkage map. In the present study 12 of these mutants were reexamined together with eight new Thr(-) strains. The three phenotypes were: homoserine-requiring (Hom(-)); Thr(-), feeders of Hom(-) strains; Thr(-), nonfeeders. Exact correlation between these phenotypic groups and three complementation groups was confirmed by abortive transduction. No evidence was found for intergenic complementation between mutations in Hom(-) strains. It is proposed that thr mutations define three genes rather than four and that these be renamed thrA (Hom(-)), thrB (Thr(-) feeders), and thrC (Thr(-) nonfeeders) to correspond with the sequence of reactions in threonine biosynthesis. Double mutant trpRthr strains were used in reciprocal three-point transduction tests to establish the order of thr mutation sites. Although revisions were made in the classification or location of several mutations, there was an overall correlation of complementation group, phenotype, and map position. The present data provide a basis for further correlation of threonine genes and biosynthetic enzymes, and analysis of cross regulation in aspartate amino acid biosynthesis in Salmonella.

Purification of Races B and C of the Hessian Fly1 by Genetic Manipulation2

A procedure was worked out to obtain genotypically homozygous progenies of Races B and C of Mayctiola destructor (Say) by manipulation of genes of these races. Avirulent (unable to survive or stunt) larvae are known to survive on resistant wheat cultivars when together with virulent (able to survive and stunt) larvae. Therefore, by leaving a single egg per plant, only a homozygous virulent larva was able to survive on a susceptible cultivar, but it could still be heterozygous for virulence to a cultivar with a different resistance. Additionally, interracial reciprocal progeny testing was used to identify heterozygous flies. They were discarded, and only homozygous flies were saved for further increase to genotypically pure populations.

The development of mating propensity in two karyotypes of Drosophila persimilis

Progeny from twenty homokaryoptypic strain crosses (ten each for KL and MD arrangements of Drosophila persimilis from Humboldt County, California) were tested for time (days) from eclosion to onset of mating activity (‘switch-on’ of female receptivity). Identically-aged flies on days 1, 2, 3 and 4 following eclosion were introduced into plastic chambers and observed for 30 min, ten pairs per chamber and 100 pairs per cross. Percentages of mating in 30 min (mating activity) and in the first 5 min (mating speed) were recorded. Of the twenty crosses, four of KL and one of MD failed to achieve a level of mating attained by the remaining fifteen ‘normals’ so that switch-on was not ascertainable from them. Among normals, however, KL was significantly higher in mating activity on day 2 than MD, but cumulative total matings caught up in MD so that by day 4 there was no difference between karyotypes. Mating speed was low on day 2 but increased variably on days 3 and 4. Reciprocal age tests ruled out increase in male courtship after day 2 but suggested a decrease in threshold level of females (courtship summation), A positive regression between mating speed and activity on days 3 and 4 suggested that switch-on and courtship summation may not be under independent genetic control.

Millimeter-wave investigation of electronic conduction in semiconducting III-V compounds

The small-signal microwave conductivity of n-type single-crystal InSb, GaSb, InAs, and epitaxial GaAs under the influence of a heating dc field was studied experimentally at 4-mm waves. Contrary to low-frequency results, the millimeter-wave conductivity of InSb at 78 K increases with increasing dc field as a consequence of relaxation effects. The anisotropy with respect to the direction of this field is reversed so that the conductivity for parallel dc and ac fields exceeds the conductivity for perpendicular fields. Mean momentum and energy relaxation times τm and τε, respectively, are evaluated from the conductivity data: τε, almost constant, is about 2×10−12sec, τm drops from 6.1×10−12 sec and 2.6×10−12 sec, depending upon sample mobility, to some 2×10−12 sec when the electric field is increased from zero to 170 V/cm. Agreement of microwave τm with dc measured values is satisfactory. In GaSb at 300 K and 85 GHz, relaxation effects show up in a pronounced deviation of the parallel microwave conductivity from the differential conductivity in the field range from 1 to 3 kV/cm, indicating that the time constants for Γ-L intervalley electron transfer are of the order of the reciprocal test frequency and that the Γ-L intervalley coupling constant is around 3×108 eV/cm. At low heating fields, the warm-electron parameter β was measured for InSb at 78 K, GaAs at 300 K, and InAs at both temperatures by a microwave method. Positive values were found in InAs [78 K: (4.9±0.8)×10−7cm2 V−2; 300K: 2×10−8cm2 V−2], negative ones in GaAs [(1.1±0.6)×10−8 cm2 V−2] and InSb [high-mobility material (−1.9±0.6)×10−4 cm2 V−2; low-mobility material: −4.6×10−6cm2 V−2]. The results are discussed in terms of various theories.

MUTANTS DEFICIENT OR ALTERED IN BRANCHED-CHAIN-AMINO- ACID AMINOTRANSFERASE IN <i>SALMONELLA TYPHIMURIUM</i>

Ten ilv multisite mutants deficient in both branched-chain-amino-acid aminotransferase and α, β-dihydroxyacid dehydratase activities were isolated from wild-type and ilvD18 strains Salmonella typhimurium LT2. One of these mutants, KA109, harbors an additional deficiency in the activity of the reductoisomerase. From these mutants, five Ile- strains possessing a defect in the branched-chain-amino-acid aminotransferase were isolated by P22 transduction. The TR109 and DT101 strains (Ile-) grow slow and irregular in minimal medium containing isoleucine unless supplementation with leucine and valine in the medium is made. All Ile- strains accumulate α-keto-β-methylvalerate as well as pyruvate and an unknown α-keto acid in the culture media; α-ketoisovalerate and α-ketoisocaproate have not been detected. By mutual and reciprocal cotransduction tests using ilv multisite mutant as recipient and Ile- mutant as donor, an arrangement of the Ile- mutational sites in ilvE locus was obtained.

Pathogenicity for cattle of Allerton-type herpesvirus isolated from a Tanzanian buffalo ( Syncerus caffer)

Experimental infection with an Allerton-type herpesvirus of buffalo origin (BA) was studied in East African grade cattle inoculated by different routes. Intravenous inoculation of large doses caused skin lesions in only 4 of 10 cases. Epithelial necrosis and erosion were observed on the tongue and in the nares of animals inoculated intradermolingually and also by the intravenous route. There was no clinical or serological reaction following contact or intranasal exposure. The excretion of virus and the development of neutralising antibody was investigated; more virus was detected in nasal than in oral swabs. The BA strain of Allerton virus was compared with two other African isolates by reciprocal neutralisation tests, using hyperimmune rabbit sera. No significant differences were demonstrable.

Change in the fracture strength of structural steels under the influence of cyclic stresses

1. In evaluating the viscosity of structural steels from the standpoint of fracture mechanics, it is necessary to take into account the local changes in the properties of the metal that occur during formation of specific initial defects, including fatigue cracks. 2. The cyclic deformation cumulative ahead of a fatiguecrack front and the deformation aging of the metal in these zones materially alter the initial viscosity of low-carbon and low-alloy steels. The character of these changes depends on the preliminary cyclic loading regime and especially on the aging rate and the tendency of the material toward aging. 3. Deformation aging of low-carbon steels and low-alloy steels with a tendency to age reduces their fracture strength, as manifested in an increase in the lower critical temperature and a considerable decrease in the critical crack width in the quasibrittle range. Cyclic cold working (without aging) under similar conditions leads to a temporary increase in the viscosity of the metal, as a result of a rheotropic inversion effect. Aging must therefore be considered as an obligatory procedure in testing materials with a tendency toward this process. 4. The linear relationship established by some authors between the logarithm of the critical crack width and the reciprocal test temperature [11, 12] was found to be lacking for some materials. As a result, it is premature to conduct tests on different classes of steels on the basis of the assumed existence of such relationships.

The Dependence of Immunological Cross-Reactivity upon Sequence Resemblance among Lysozymes: I. MICRO-COMPLEMENT FIXATION STUDIES

Rabbit antisera were prepared against seven different lysozymes purified from the egg whites of chicken, bobwhite quail, turkey, Japanese quail, ring-necked pheasant, and duck. Cross-reactivity tests by means of quantitative micro-complement fixation were conducted among all possible pairs of these lysozymes as well as with three other lysozymes. The amino acid sequences are known for five of the 10 proteins we examined. A correlation was observed between degree of immunological cross-reactivity and degree of amino acid sequence similarity, with the limitation that proteins differing from each other by 40% or more in sequence exhibited no cross-reactivity in micro-complement fixation tests. This relationship between sequence resemblance and immunological resemblance is compatible not only with the fact that amino acid replacements have generally occurred on the outer surface of the lysozyme molecule during bird evolution but also with current ideas about the size and number of antigenic determinants on proteins and with the idea that the conformation of the polypeptide backbone is strongly conserved during evolution. Cross-reactivity measurements are affected by several parameters that were investigated, including the length of the immunization program, variability among rabbits, and the degree to which the results of reciprocal tests agree. Antiserum specificity broadened with time and reached a plateau after several months of immunization. Considerable variability among rabbits necessitated pooling several sera in inverse proportion to their degree of reaction with the homologous antigen in order to obtain a more representative measurement. The results of reciprocal tests advise measuring cross-reactivity in both directions to better evaluate the degree of antigenic difference between two lysozymes.

Chemical and immunological characterization of cucumber green mottle mosaic virus (watermelon strain) protein

The chemical and immunological properties of the protein of cucumber green mottle mosaic virus, watermelon strain (CGMMV-W), are presented. Amino acid analysis, amino-terminal residue (acetylalanine), and carboxyterminal amino acid (alanine) indicate that CGMMV-W is chemically related to cucumber virus 4 (CV-4). The serological relationship of CGMMV-W to CGMMV-C (cucumber strain), TMV-OM (common strain), and TMV-T (tomato strain) was confirmed by reciprocal tests. Heterologous reactions showed different degrees of serological relationship among the four strains. CGMMV-W was found to be more closely related to TMV-OM than to CGMMV-C and TMV-T. The partial amino acid sequences, containing residues 91–122, of CGMMV-W protein were determined and compared with those of other TMV or CGMMV proteins. Fifteen out of 32 amino acids were common to the CGMMV-W and TMV-OM proteins. We think it is high enough to consider that CGMMV-W has an ancestral relationship to TMV.

Characteristics of an Isolate of Infectious Bronchitis Virus from Chickens in Florida

SUMMARY An isolate of infectious bronchitis virus (IBV) from a commercial White Leghorn laying flock in Florida was found to be serologically different from Massachusetts, Connecticut, Gray, Holte, Iowa 97, Iowa 609, and JMK types. Two different Massachusettstype IB vaccine virus strains and Connecticut-type IBV failed to protect chickens against respiratory signs and infection in laboratory trials. In reciprocal cross-immunity tests when used as a vaccine the Florida isolate failed to protect satisfactorily against Massachusetts, Iowa 609, Iowa 97, Gray, JMK, and SE17 viruses. Good protection was obtained against Holte-type virus, a nephritis-inciting isolate, even though it was not related to it serologically. The virus was labile in the presence of chloroform, heat (56 C), and an acid pH (3.0). The affected flock from which the virus was isolated experienced a drop in egg production with a concurrent reduction in shell quality, though it had been vaccinated with Massachusetts and Connecticut IBV serotypes. The implication of the multiplicity of IBV serotypes and their impact on vaccination programs are discussed. It is suggested that the new isolate be designated Florida-type IBV.

Contact hybridization in the Crinia laevis complex (Anura : Leoptodactylidae)

Mating-call structure was used to determine the nature and extent of an interaction between the two morphologically indistinguishable taxa, C. laevis and C. victoriana, where their geographic ranges contact in south-western Victoria. Intermediacy of mating-call structure was detected in a zone about 115 km long and less than 2 km wide. Acoustic analysis of call samples from six localities indicated that hybrids, backcross progeny, and one or both parental types were present in this zone. Results of reciprocal artificial hybridization tests between allopatric individuals of the two taxa showed that there was a high level of interfertility in both combinations, but with slightly reduced survival to metamorphosis. Presumed backcrosses using males from the hybrid zone resulted in a higher level of survival to metamorphosis. The zone does not coincide with any conspicuous ecotone and presumably represents a complex balance point with various environmental factors contributing to a greater or lesser extent in different parts of the contact. In spite of this lack of reproductive isolation, the narrowness of the zone and the presumed antiquity of the contact demonstrate that the taxa will continue to maintain their distinctness, and should retain their specific status.

An Influenza B Epidemic Within a Remote Alaska Community

During January 1969 an epidmic of influenza B was documented in Klawock, Alaska, a remote insular community 80 miles west of Ketchikan. One person died and 149 others developed an acute respiratory disease characterized by fever, cough, headache, and coryza. A fourfold or greater rise in hemagglutination-inhibiting (HI) antibody titer to influenza B developed in 26 persons, and influenza B virus was isolated from 5 patients. Reciprocal HI testing of the Alaska strain (B/Alaska/4-69) did not disclose a significant antigenic difference from the vaccine strain (B/Massachusetts/3-66). However, 36 of the 46 persons who had been vaccinated during the preceding 3 to 12 months developed clinical influenza, and the attack rate within this group did not differ significantly from the attack rate among the unvaccinated population.

Time Reversal and Reciprocity in Direct Reactions

Direct-reaction reciprocity tests of time-reversal invariance are analyzed on general grounds and specifically with the T-violating force derived in the preceding paper. A simple proof of Robson's theorem that a cut-off distorted wave Born approximation satisfies reciprocity irrespective of $T$ violation is indicated. Numerical calculations are described which show that Robson's theorem is not a severe restriction on direct-reaction reciprocity tests, and that the violation of reciprocity is of the same order of magnitude as the ratio of the $T$-odd to $T$-normal forces. If the $T$-violating term of the nucleon current contains an isovector part, the $T$-odd potential derived in the preceding paper implies roughly 0.2% violation of reciprocity in deuteron stripping. However, if the basic $T$ violation is isoscalar, the violation of reciprocity will be reduced by a factor of 50 in the context of the model considered.

Serologic Classification of Chimpanzee Adenoviruses by Hemagglutination and Hemagglutination Inhibition

Abstract Twenty-two strains of viruses, each possessing adenovirus complement-fixing antigen and each derived from fecal specimens of chimpanzees, have been classified by their hemagglutinating properties into three major subgroups. Subgroup I is composed of eight strains which cause hemagglutination of rhesus or vervet monkey erythrocytes; subgroup II consists of 12 strains which agglutinate selected Sprague-Dawley rat erythrocytes in the presence of heterotypic immune serum to members of the Rosen subgroup III of human adenoviruses; and finally, chimpanzee subgroup III is composed of two strains which fail to agglutinate monkey, rat, guinea pig, or human type O erythrocytes. HAI reciprocal tests suggest that all eight of the subgroup I strains are related to prototype C-1 chimpanzee adenovirus, as well as to human adenovirus type 16. Six strains of subgroup II are closely antigenically related to each other and to human adenovirus type 5 by HAI. Four additional strains are partially cross-reactive in HAI tests with human adenovirus type 2 and highly cross-reactive with one another. The remaining two strains of subgroup II apparently represent previously unreported serotypes without relationships to known adenoviruses or to each other, as demonstrable by HAI techniques. Evidence is presented that the 22 strains represent a total of at least seven distinct chimpanzee serotypes of adenovirus.

Evolutionary Relationships in the Bufo punctatus Group

A detailed investigation of populations of four species of Southwestern anurans (genus Bufo) demonstrated that Bufo debilis, B. retiformis, B. kelloggi and B. punctatus constitute a natural species group to be known as the punctatus group. Of the four species, B. punctatus Baird and Girard is the most similar to a common ancestral stock which probably existed during Mio-Pliocene time as the fossil species Bufo suspectus Tihen. Reciprocal hybridization tests indicated that (1) more hybrid development occurs when crosses within the group involve B. punctatus as one parental species, (2) the other three members of this group are more strongly isolated genetically from each other than was first assumed from their general appearance and behavior, and from former investigations, and (3) the genetic compatibilities between members of the group are in the following order of increasing divergence from the ancestral stock: B. punctatus-B. kelloggi-B. debilis-B. retiformis. Species divergence on a morphological basis could only be convincingly demonstrated through qualitative characteristics. Morphological differences were of smaller magnitude than previously suspected, and were found to agree favorably with the results of hybridization. Sound spectrographic analysis revealed further evidence for including these four species in the same species group. Call frequency depends on body size, and the relationship of snout-vent length to the frequency of the basic harmonic of each call was found to be the same for each species. The major habitat of each species in the Southwest is identified and relationships are discussed with respect to the ecology of each. The evolution of the B. punctatus group has been associated with the evolution of modern derivative communities of the Madro-Tertiary Geoflora within which each of the four species occurs today.

Rhinoviruses: the isolation and characterization of three new serologic types.

SummaryThree new rhinovirus immuno-types (FO2-2317, FO2-2513 and FO2-2547) were recovered from military recruits at Fort Ord, California. These new viruses were shown to be small RNA viruses which are inactivated at low pH and do not contain lipids as an essential structural component. Thus, they can be classified as human rhinoviruses. Reciprocal neutralization tests show them to be serologically distinct from the presently recognized 55 prototype rhinoviruses and on the basis of one-way neutralization tests they also appear to be distinct from certain other previously described candidate rhinoviruses.

シミアンウイルスの研究

A strain of SV 41 given by R. M. Chanock was grown and passaged in Vero cells (Cercopithecus kidney cell line). In the reciprocal cross neutralization tests among Paramyxoviruses SV 41 was clearly distinguished from other viruses except that slight crossing was observed against CA virus. Some physico-chemical tests, including size determination by filtration, sensitivity to chloroform and nucleic acid typing using IUDR, and some host range tests gave results essentially consistent with those described originally by Miller et al. on primary culture-grown viruses. Contrary to our expectation in the heating tests at 50°C SV 41 was not labile; that is, after heating for 9 hours a decline of infectivity by 5 logs was demonstrated but still left 1.5 log of infectivity.Search for serum neutralizing antibodies in humans, monkeys and various experimental and domestic animals revealed that the sole species which gave positive results was humans and no positives were encountered in 321 monkeys including Cynomolgus, Rhesus and Cercopithecus species which were imported from 1960 to 1966 and kept for varying periods of time in this laboratory, Whether the SV 41 antibodies in humans are due to infections of SV 41 itself or not can not be decided from our present data. Its confirmation waits for future investigations.

2334 正負の繰返し曲げを受ける合成ばりの耐力試験(構造)

2334 正負の繰返し曲げを受ける合成ばりの耐力試験(構造)