MINIMAL ANTIGENIC CONSTITUTION OF 28 STRAINS OF RHIZOBIUM JAPONICUM

1965 ◽  
Vol 11 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R. A. Date ◽  
A. Morris Decker

Somatic antigen groups and minimal somatic antigen constitution of 28 strains of Rhizobium japonicum were determined on the basis of their somatic cross-reactions and agglutinin absorptions. A total of 17 serological groups and 24 antigens was proposed to account for the reactions obtained. Some groups consisted of a complex of three or four strains while others comprised only one strain. Still others were composed of strains which were common to two serological groups. The antigenic complexity of rhizobial cells and the possibility of using "key-antisera" and polyvalent mixtures of "key-antisera" are discussed in relation to the classification of large numbers of field or greenhouse nodule isolates in Rhizobium competition studies.


2019 ◽  
Vol 27 (2) ◽  
pp. 20-58
Author(s):  
Jacques Van Impe

Abstract The well-known Russian ornithologist Prof. Peter Sushkin described it as a distinct species from Bashkortostan (Bashkiria) in 1897, a highly acclaimed discovery. However, its breeding grounds never been discovered. Since then, there has been a long-standing debate over the taxonomic position of Anser neglectus. Taxonomists have argued that Anser neglectus belongs to the group of A. fabalis Lath. because of its close resemblance with A. f. fabalis. At the beginning of the 20th century, large numbers of the Sushkin’s goose were observed in three winter quarters: on two lakes in the Republic of Bachkortostan, in the surroundings of the town of Tashkent in the Republic Uzbekistan, and in the puszta Hortobágy in eastern Hungary. It is a pity that taxonomists did not thoroughly compare the Russian and Hungarian ornithological papers concerning the former presence of Anser neglectus in these areas, because these rich sources refer to characteristics that would cast serious doubt on the classification of Anser neglectus as a subspecies, an individual variation or mutation of A. f. fabalis. Sushkin’s goose, though a typical Taiga Bean Goose, distinguished itself from other taxa of the Bean Goose by its plumage, its field identification, by its specific “Gé-gé” call, the size of its bill, and by its preference for warm and dry winter haunts. A. neglectus should therefore be considered a separate, fully distinct species, sensu Stegmann (1935) and Stegmann in Schenk (1931/34), if we follow the established criteria in bird systematics of Tobias et al. (2010). Between 1908 and 1911, an estimation of up to 150.000 individuals of A. neglectus wintered in the Hortobágy puszta. Approximate counts for both other winter quarters are not available. The last living birds were seen in the zoological garden of Budapest in 1934. Since then, A. f. fabalis and A. s. rossicus “Type neglectus” (i.e. A. f. fabalis and A. s. rossicus with a color of the bill and the legs, similar to the former A. neglectus) have been observed sporadically on the breeding grounds and in the winter quarters of both taxa. However, the true A. neglectus seems to be extinct. Its sudden disappearance may be related to the Tunguska event, the catastrophe in 1908 that may have caused genetic mutations. This hypothesis is considered to be the most likely, among other available hypotheses about its extinction.



PEDIATRICS ◽  
1958 ◽  
Vol 22 (4) ◽  
pp. 616-627
Author(s):  
Douglas C. Heiner

An easy-to-perform immunologic test for histoplasmosis is described. The test, involving precipitin reactions in agar gel, appears to have greater sensitivity and specificity than currently available tests for histoplasmosis. It is useful in the study of small or large numbers of patients. It has been possible to demonstrate at least one antigen common to H. capsulatum, B. dermatitidis, and C. immitis. This antigen may be responsible for cross reactions. Instances are cited wherein problems of cross reactions and false-positive reactions have been clarified by means of precipitin-in-gel studies. Precipitin reactions in agar have provided presumptive diagnosis of histoplasmosis in a patient with acute pericarditis, which rapidly progressed to constrictive pericarditis necessitating pericardiectomy.





1977 ◽  
Vol 79 (2) ◽  
pp. 233-241 ◽  
Author(s):  
K. M. Elhag ◽  
K. A. Bettelheim ◽  
Soad Tabaqchali

SUMMARYUsing direct agglutination methods, a simple serological scheme for the classification ofBacteroides fragilisis described. Twenty strains ofB. fragiliswere selected by a process of successive screening from 151 strains obtained from various sources. O-antigens were prepared from the 20 strains, and used to raise antisera in rabbits.Each of the 20 antisera reacted with its homologous antigen and eight antisera cross-reacted with other subspecies. These cross-reactions were successfully removed after absorption of the antisera with the cross-reacting antigens, resulting in 19 type-specific antisera, titres ranging from 40 to 320, and 19 distinct serotypes ofB. fragilis. There was no correlation between the antigenic and the biochemical characteristics of these strains and no cross-reactions occurred with other gram-negative anaerobes,B. melaninogenicus, Sphaerophorus necrophorusandFuso-bacterium necrogenes.



1984 ◽  
Vol 102 (2) ◽  
pp. 487-497 ◽  
Author(s):  
H. J. B. Lowe

SummaryVariation in infestation of S. avenae on plots of wheat was assessed by combining techniques of enhancing field infestations with scoring individual shoots according to the number of aphids on them, using a logarithmic scale with base 2. The mean score appeared the most useful way of describing the aphid infestation on each plot.In 1982, the sampling effort required for assessment of S. avenae on many plots was considerably reduced by this approach. The artificial increase in numbers of aphids avoided problems associated with sampling small populations, and the logarithmic classification of shoots reduced the time needed to assess large numbers. Scoring plots as a whole, although much quicker, gave results that differed from the assessments based on shoot sampling, and should be used with caution. The differences observed among cultivars in infestation of adult plants in the field in 1982 were not always the same as those observed on younger plants in the glasshouse.



1977 ◽  
Vol 4 (2) ◽  
pp. 67-70 ◽  
Author(s):  
D. F. Gilman ◽  
O. D. Smith

Abstract Fruit of 10 peanut (Arachis hypogaea L.) genotypes differing in botanical type and geographical source were evaluated to establish parameters for making reliable maturity determinations on the basis of internal pericarp color (IPC), and to compare the IPC, kernel density (KD) and arginine maturity index (AMI) methods of estimating peanut maturity. Kernels from fruits with detectable, non-disease related internal pericarp darkening were significantly lower in density than kernels from fruits without internal pericarp darkening. No difference in density was detected between kernels from fruits differing in intensity of internal pericarp darkening. In general, two-seeded fruits with detectable non-disease related darkening in at least one orbital of the pericarp were mature, whereas fruits with no internal pericarp darkening were immature. Mature fruit percentages were determined on sample sizes of 25, 50, 75, and 100 fruits. Although standard errors were consistently high for 25-fruit samples, means and standard errors were similar for sample sizes of 50, 75, and 100 fruits, indicating that estimates based on 50-fruit samples were reliable. Post-harvest stability of IPC was evaluated from determinations made on five dates at 30-day intervals. IPC did not change sufficiently during the 120 day period to affect the maturity estimates. Kernel samples classified as mature by the IPC method were significantly lower in density and free arginine content than kernels classified as immature. Correlations among maturity estimates using the IPC, KD and AMI methods were highly significant, with all coefficients exceeding 0.95. The results indicate that peanut samples can be evaluated reliably for maturity by subjective classification of IPC. Maturity estimates on the basis of IPC were as effective as those determined using either the KD or AMI methods. The IPC method requires no sophisticated equipment and it is simple, rapid and nonsacrificial which makes it particularly useful in breeding programs involving large numbers of maturity determinations.



Author(s):  
Abdul Latief RF ◽  
Chatarina Muryani ◽  
Yasin Yusup

<p><em>Since the tsunami in 2004 in the Indian Ocean, studies of the megatrust tsunami have been increasing. One of the reasons is because the megatrust tsunami can cause large numbers of casualties, as has happened in Aceh and Mentawai (Indonesia). The threat of a megatrust tsunami now stretches along the coastline of the southern island of Java. Communities who are in the southern part of Java, ideally have the ability to be prepared to face a tsunami disaster. Therefore, an assessment of community preparedness in the face of a tsunami in Purworejo Regency is an urgency, because Purworejo is one of the regencies directly adjacent to the ocean in the south of Java Island. This study uses a combination of questionnaires, interviews, observation and documentation to obtain data. This study provides information on the classification of villages along the coast of Purworejo in relation to the level of preparedness to face the threat of a tsunami disaster. The result is that from 16 villages 2 of them are of high status, 2 are low and the rest are moderate.</em></p>



2019 ◽  
Vol 626 ◽  
pp. A59 ◽  
Author(s):  
J. S. Clark ◽  
B. W. Ritchie ◽  
I. Negueruela

Context. X-ray emission from massive stars was first reported four decades ago, but the precise physics governing its formation as a function of stellar properties and binarity remains not fully understood. With the recent suggestion that such objects may be important sites of cosmic ray production, a better understanding of their high-energy properties is particularly timely. Aims. The young massive cluster Westerlund 1 provides an ideal testbed for understanding this emission, with over 50 cluster members detected in historical X-ray observations. In the decade since these data were obtained, significant new multi-epoch observations of the cluster have been made, allowing a fundamental reappraisal of the nature of both X-ray bright and dark stars. Methods. Optical spectroscopy permits accurate classification of cluster members, while multi-epoch observations of a sub-set allow identification and characterisation of the binary population. Results. A total of 45 X-ray sources within Wd1 now have precise spectral classifications. Of these, 16 have been identified as candidate or confirmed massive binaries. X-ray emission is confined to O9-B0.5 supergiants, Wolf-Rayets and a small group of highly luminous interacting/post-interaction OB+OB binaries. Despite their presence in large numbers, no emission is seen from earlier, less evolved O stars or later, cooler B super-/hypergiants. A total of 22 stars have X-ray properties that are suggestive of a contribution from emission originating in a wind collision zone. Conclusions. We suppose that the lack of X-ray emission from O giants is due to their comparatively low intrinsic bolometric luminosity if, as expected, they follow the canonical LX/Lbol relation for hot stars. The transition away from X-ray emission for OB supergiants occurs at the location of the bistability jump; we speculate that below this limit, stellar wind velocities are insufficient for internal, X-ray emitting shocks to form. Our results are consistent with recent findings that massive binaries are not uniformly brighter than single stars of comparable luminosity or spectral type, although it is noteworthy that the brightest and hardest stellar X-ray sources within Wd1 are all either confirmed or candidate massive, interacting/post-interaction binaries.



1986 ◽  
Vol 24 (1) ◽  
pp. 152-154 ◽  
Author(s):  
Y Nakamura ◽  
S Hyodo ◽  
E Chonan ◽  
S Shigeta ◽  
E Yabuuchi


1933 ◽  
Vol 33 (4) ◽  
pp. 510-515 ◽  
Author(s):  
H. J. O'D. Burke-Gaffney

1. 1000 urinary and 500 faecal cultures of coliform bacteria were studied by means of the methyl-red, citrate and indol tests and also by their fermentation reactions upon saccharose and dulcite.2. 8 per cent, of the faecal strains and 52 per cent, of the urinary strains were of theaerogenestype,i.e.methyl-red negative and citrate positive. Indol was produced in 94 per cent, and 43 per cent, of cases respectively.3. This would suggest additional evidence that thecoligroup are quickly outnumbered by theaerogenesgroup once they leave the faeces, and also that the presence of theaerogenestype is not confined even in large numbers to an extra-corporeal habitat.4. In water bacteriology the constancy or change in the relative proportions ofcoliandaerogenesstrains present is the goal at which to aim. Theaerogenesvariety cannot of itself be regarded as non-excretal or even non-faecal.5. From a sanitary standpoint, the classification of coliform bacteria by means of the methyl-red and citrate tests cannot be regarded as entirely free from error so long as (a) theaerogenesstrains are found in faeces, in however small numbers, (b) these strains occur as the predominant type in urine, and (c) intermediate strains are found in the faeces, urine, soil and water.6. The principal value of these tests lies in their comparative specificity in identifyingB. coliof immediate faecal origin. The presence of such an organism, interpreted together with the indol test, may be said to suggest dangerous faecal pollution if found prominently in a water sample. The presence of other types identified by the same tests cannot be regarded as having the same significant value in regard to a negative opinion.7. A plea is made for a further study of coliform bacteria by means of the tests described in relation to the biological behaviour of the bacteria under different environmental conditions.



Sign in / Sign up

Export Citation Format

Share Document