9 research outputs found
Ecological drivers of helminth infection patterns in the Virunga Massif mountain gorilla population
The Virunga Massif mountain gorilla population has been periodically monitored since the early 1970s, with gradually increasing effort. The population declined drastically in the 1970s, but the numbers stabilized in the 1980s. Since then, the population has been steadily increasing within their limited habitat fragment that is surrounded by a dense human population. We examined fecal samples collected during the Virunga 2015–2016 surveys in monitored and unmonitored gorilla groups and quantified strongylid and tapeworm infections using egg counts per gram to determine environmental and host factors that shape these helminth infections. We showed that higher strongylid infections were present in gorilla groups with smaller size of the 500-m buffered minimum-convex polygon (MCP) of detected nest sites per gorilla group, but in higher gorilla densities and inhabiting vegetation types occurring at higher elevations with higher precipitation and lower temperatures. On the contrary, the impact of monitoring (habituation) was minor, detected in tapeworms and only when in the interaction with environmental variables and MCP area. Our results suggest that the Virunga mountain gorilla population may be partially regulated by strongylid nematodes at higher gorilla densities. New health challenges are probably emerging among mountain gorillas because of the success of conservation efforts, as manifested by significant increases in gorilla numbers in recent decades, but few possibilities for the population expansion due to limited amounts of habitat
Changes induced by powdery mildew in the salicylic acid and polyamine contents and the antioxidant enzyme activities of wheat lines
Investigations were made on four wheat
(Triticum aestivum L.) lines under greenhouse conditions,
in order to reveal the role of stress-protective
materials, namely salicylic acid, polyamines and antioxidant
enzymes in the level of tolerance to powdery
mildew infection caused by Blumeria graminis (DC.)
Speer f.sp. tritici Ém. Marchal. The four lines showed
different levels of tolerance, assessed on the Saari-
Prescott scoring scale: TC26 and TC33 proved to be
susceptible and TC9 and TC19 resistant. In most of the
lines, infection caused changes in the activities of antioxidant
enzymes, especially in the case of guaiacol peroxidase.
Four peroxidase isoenzymes, which responded
differently to powdery mildew infection could be
detected by gel electrophoresis. Infection had only a
slight effect on the levels of salicylic acid (free and
bound forms) in inoculated plants; while the levels of
polyamines, especially spermidine and spermine increased
after infection. Correlation analysis was also
performed to examine how close a relationship exists
between the parameters investigated. It was concluded
that salicylic acid, polyamines and antioxidant enzymes
have an important role in plant responses and defence
mechanisms during this biotic stress and that in some
cases there were significant relationships between them