Estimation of Stature from Living Adult Females belonging to Tamil Population using Percutaneous Tibial Length

Parasitology ◽  
2005 ◽  
Vol 131 (3) ◽  
pp. 383-392 ◽  
Author(s):  
M. CROOK ◽  
M. E. VINEY

Strongyloides ratti is a parasitic nematode of rats. The host immune response against S. ratti affects the development of its free-living generation, favouring the development of free-living adult males and females at the expense of directly developing, infective 3rd-stage larvae. However, how the host immune response brings about these developmental effects is not clear. To begin to investigate this, we have determined the effect of non-immune stresses on the development of S. ratti. These non-immune stresses were subcurative doses of the anthelmintic drugs Ivermectin, Dithiazanine iodide and Thiabendazole, and infection of a non-natural host, the mouse. These treatments produced the opposite developmental outcome to that of the host immune response. Thus, in infections treated with subcurative doses of Ivermectin, Dithiazanine iodide and in infections of a non-natural host, the sex ratio of developing larvae became more female-biased and the proportion of female larvae that developed into free-living adult females decreased. This suggests that the mechanism by which the host immune response and these non-immune stresses affect S. ratti development differs.


2018 ◽  
Vol 99 (6) ◽  
pp. 1583-1586 ◽  
Author(s):  
Joelma Nascimento De Souza ◽  
Barbara Nascimento Rocha Ribeiro Soares ◽  
Luana Leandro Goes ◽  
Cintia de Souza Lima ◽  
Nilo Manoel Pereira Vieira Barreto ◽  
...  

1964 ◽  
Vol 45 (1) ◽  
pp. 1-12 ◽  
Author(s):  
H. E. Swanson ◽  
J. J. van der Werff ten Bosch

ABSTRACT The »early-androgen« syndrome in the rat – i. e. anovulatory ovaries in adult females after a single injection of testosterone propionate (TP) within a week of birth – may not become apparent until some time after the attainment of sexual maturity. Large doses (50 or 100 μg) of TP were effective earlier than lower doses (5 or 10 μg). Rats which received 5 μg TP were ovulating at 10 weeks of age, mated but were infertile at 13 weeks of age, and were anovulatory at 21 weeks. In rats between 10 and 13 weeks old there was a marked fall in the number of corpora lutea in the ovaries of animals which had been given 5 μg TP. Hemi-spaying was followed by compensatory growth of the remaining ovary which consisted of corpora lutea in ovulating, and of follicles in anovulatory rats; little or no compensatory weight increase occurred in animals which seemed to be in the transition stage from the ovulatory to the anovulatory condition.


Acarina ◽  
2020 ◽  
Vol 28 (1) ◽  
pp. 55-64
Author(s):  
Omid Joharchi ◽  
Elizabeth Hugo-Coetzee ◽  
Sergey G. Ermilov ◽  
Alexander A. Khaustov

Hypoaspisella spiculifer comb. n. is redescribed on the basis of adult females, collected from soil in South Africa. Hypoaspisella spiculifer fits well with the current concept of the genus Hypoaspisella Bernhard. The chelicerae of this species are similar to those of free-living mites, suggesting that it may be a predator of small soil invertebrates.


1974 ◽  
Vol 104 (10) ◽  
pp. 1348-1355 ◽  
Author(s):  
Heaja Kim Shin ◽  
Hellen M. Linkswiler

2021 ◽  
Vol 9 (6) ◽  
pp. 1242
Author(s):  
Loganathan Ponnusamy ◽  
Haley Sutton ◽  
Robert D. Mitchell ◽  
Daniel E. Sonenshine ◽  
Charles S. Apperson ◽  
...  

The transovarial transmission of tick-borne bacterial pathogens is an important mechanism for their maintenance in natural populations and transmission, causing disease in humans and animals. The mechanism for this transmission and the possible role of tick hormones facilitating this process have never been studied. Injections of physiological levels of the tick hormone, 20-hydroxyecdysone (20E), into part-fed (virgin) adult females of the American dog tick, Dermacentor variabilis, attached to the host caused a reduction in density of Rickettsia montanensis in the carcass and an increase in the ovaries compared to buffer-injected controls. This injection initiates yolk protein synthesis and uptake by the eggs but has no effect on blood feeding. Francisella sp. and R. montanensis were the predominant bacteria based on the proportionality in the carcass and ovary. The total bacteria load increased in the carcass and ovaries, and bacteria in the genus Pseudomonas increased in the carcass after the 20E injection. The mechanism of how the Rickettsia species respond to changes in tick hormonal regulation needs further investigation. Multiple possible mechanisms for the proliferation of R. montanensis in the ovaries are proposed.


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