scholarly journals The avian haemophili.

1989 ◽  
Vol 2 (3) ◽  
pp. 270-277 ◽  
Author(s):  
P J Blackall

There are four currently recognized taxa to accommodate the avian haemophili: Haemophilus paragallinarum, Pasteurella avium, Pasteurella volantium, and Pasteurella species A (the last three being formerly united as Haemophilus avium). A range of other taxa has also been recognized, but they have been neither named nor assigned to a genus. All of these various taxa, legitimate and otherwise, have the common characteristic of requiring V factor, but not X factor, for in vitro growth. Several recent studies have established the phenotypic properties that allow the differentiation of the recognized taxa, both named and unnamed. The serological properties of H. paragallinarum, the causative agent of infectious coryza of chickens, has received considerable recent attention. In contrast, many questions on the pathogenicity and virulence mechanisms of H. paragallinarum remain unanswered. Another area requiring further work is the identification of those antigens responsible for inducing protective immunity in vaccinated or naturally infected chickens.

2018 ◽  
Vol 5 (2) ◽  
pp. 224
Author(s):  
Dewa Ayu Andriastini ◽  
Yan Ramona ◽  
Meitini Wahyuni Proborini

A research on in vitro inhibition of fungal antagonists, isolated from dragon fruit plantation in Sembung village, Bali, on Fusarium sp. (the disease causative agent of dragon fruit plant) was conducted with the main objective to investigate the effectiveness of these fungal antagonists to inhibit the in vitro growth of the pathogen. Dual assay method was applied in this experiment. The results showed that three potential fungal antagonists were successfully isolated in this research and they were identified as Trichoderma harzianum, Aspergillus niger, dan Paecilomyces lilacinus. All these fungal antagonists showed antagonistic activity against Fusarium sp. which was statistically significant (p<0.05) when compared to control. This indicated that all antagonist isolates were potential to be developed as biocontrol agent candidates.


1986 ◽  
Vol 163 (1) ◽  
pp. 179-188 ◽  
Author(s):  
R Schmidt-Ullrich ◽  
J Brown ◽  
H Whittle ◽  
P S Lin

Using the human lymphoblastoid cell line, GM 4672, and PBL of Gambian adults immune to Plasmodium falciparum (Pf) malaria, we have produced human-human hybridomas and selected those that produce mAb against Pf antigens. The fusion frequency, using PWM-stimulated donor lymphocytes was between 6.8 X 10(-5) and 1.5 X 10(-6). Using immune fluorescence, immune precipitation, and Pf in vitro growth inhibition, we cloned four hybridomas that reacted with the Pf Mr 195,000 schizont/merozoite protein. The differences in proteins immune precipitated and in growth inhibition indicate that, during development of protective immunity against Pf malaria, a spectrum of antibodies is produced reacting with different epitopes on the same antigen. Only a portion of these antibodies exhibits biological activity, suggesting that the recognition of certain epitopes is required for the development of a protective immune response.


Plant Disease ◽  
2003 ◽  
Vol 87 (12) ◽  
pp. 1515-1521 ◽  
Author(s):  
M. E. Sánchez ◽  
J. Venegas ◽  
M. A. Romero ◽  
A. J. L. Phillips ◽  
A. Trapero

Although root disease caused by Phytophthora cinnamomi is considered to be the most frequent and damaging disease associated with Quercus spp. decline in southwestern Spain, cankers commonly are observed on branches of declining Mediterranean Quercus spp. in this region. In surveys carried out in eight declining Quercus forests, strips of necrotic inner bark were common on diseased branches. Botryosphaeria stevensii, B. dothidea, and Diplodia sarmentorum consistently were isolated from these branches. Isolates of all three species caused cankers when inoculated onto excised Quercus branches. Inoculations on healthy branches in the field also induced canker development, but only B. stevensii caused lesions that girdled and killed the branches. The optimum temperature for in vitro growth of B. stevensii and B. dothidea was above 25°C, with slow growth at 35°C. In contrast, D. sarmentorum had an optimum temperature for growth of about 21°C, and did not grow at 35°C. The common occurrence and wide distribution of these pathogens, their association with cankers, and their ability to infect Quercus spp. suggest that they may contribute to the Quercus spp. decline in southwestern Spain.


2009 ◽  
Vol 191 (7) ◽  
pp. 2163-2168 ◽  
Author(s):  
Katherine E. Price ◽  
Andrew Camilli

ABSTRACT Streptococcus pneumoniae is the causative agent of multiple diseases, including otitis media, pneumonia, bacteremia, and meningitis. Pneumolysin (Ply), a member of the cholesterol-dependent cytolytic pore-forming toxins, is produced by virtually all clinical isolates of S. pneumoniae, and strains in which the Ply gene has been deleted are severely attenuated in mouse models of infection. In contrast to all other members of the cholesterol-dependent cytolysin family, Ply lacks a signal peptide for export. Instead, Ply has been hypothesized to be released upon autolysis or, alternatively, via a nonautolytic mechanism that remains ill defined. We determined by use of cell fractionation and Western blotting that, during in vitro growth, exported Ply is localized primarily to the cell wall compartment in 18 different serotypes in the absence of detectable cell lysis. Hemolytic assays revealed that this cell wall-localized Ply is active. Additionally, cell wall-localized Ply is accessible to extracellular protease and is detergent releasable.


2016 ◽  
Vol 77 (S 01) ◽  
Author(s):  
Ezequiel Goldschmidt ◽  
Jorge Rasmussen ◽  
Joseph Chabot ◽  
Monica Loressi ◽  
Marcelo Ielpi ◽  
...  

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