51 research outputs found
Alge na sedrenim barijerama rijeke Krke kod Žužemberka, Slovenija
Algal occurrence, with particular emphasis on diatoms, was investigated over a two-year period on the travertine barriers of the Krka River in Slovenia. The purpose of the investigation was to establish qualitative composition and the relative abundance of the periphyton. In 1999 and 2000, basic physical and chemical parameters were measured. Altogether, 81 algal taxa were determined. Most of them belonged to Bacillariophyceae. Fifteen species and subspecies were new to Slovenia, 14 of them belonging to Bacillariophyceae and one to Cyanobacteria. Most of the new species and subspecies belonged to genera Nitzschia (5) and Navicula (4).Tijekom dvije godine istraživana je prisutnost algi s posebnim naglaskom na dijatomeje na sedrenim barijerama rijeke Krke u Sloveniji. Cilj je bio utvrđivanje kvalitativnog sastava i relativne brojnosti perifitona. Tijekom 1999. i 2000. mjereni su temeljni fizikalni i kemijski parametri. Utvrđen je 81 takson algi. Većina pripada u Bacillariophyceae. Petnaest vrsta i podvrsta bilo je novo za Sloveniju, od čega 14 spada u Bacillariophyceae i 1 u Cyanobacteria. Većina novih vrsta i podvrsta pripadalo je rodovima Nitzschia (5) i Navicula (4)
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A male-produced aggregation-sex pheromone of the beetle Arhopalus rusticus (Coleoptera: Cerambycidae, Spondylinae) may be useful in managing this invasive species.
The longhorned beetle Arhopalus rusticus (Coleoptera: Cerambycidae, Spondylinae) is a common species in conifer forests of the Northern Hemisphere, but with global trade, it has invaded and become established in New Zealand, Australia, and South America. Arhopalus rusticus is a suspected vector of the phytopathogenic nematode, Bursaphelenchus xylophilus, the causative agent of pine wilt disease, which is a major threat to pine forests worldwide. Here, we report the identification of a volatile, male-produced aggregation-sex pheromone for this species. Headspace odours from males contained a major male-specific compound, identified as (2 S, 5E)-6,10-dimethyl-5,9-undecadien-2-ol (common name (S)-fuscumol), and a minor component (E)-6,10-dimethyl-5,9-undecadien-2-one (geranylacetone). Both compounds are known pheromone components for species in the same subfamily. In field trials in its native range in Slovenia, (S)-fuscumol was significantly more attractive to beetles of both sexes, than racemic fuscumol and a blend of host plant volatiles commonly used as an attractant for this species. Fuscumol-baited traps also caught significant numbers of another spondylidine species, Spondylis buprestoides (L.), and a rare click beetle, Stenagostus rufus (De Geer). The pheromone can be exploited as a cost-effective and environmentally safe tool for detection and monitoring of this invasive species at ports of entry, and for monitoring the beetle's distribution and population trends in both endemic and invasive populations
Novel, male-produced aggregation pheromone of the cerambycid beetle Rosalia alpina, a priority species of European conservation concern.
Several recent studies have demonstrated the great potential for exploiting semiochemicals in ecology and conservation studies. The cerambycid beetle Rosalia alpina represents one of the flagship species of saproxylic insect biodiversity in Europe. In recent years its populations appear to have declined substantially, and its range has shrunk considerably as a result of forest management and urbanization. Here, we collected volatile chemicals released by males and females of R. alpina. Analyses of the resulting extracts revealed the presence of a single male-specific compound, identified as a novel alkylated pyrone structure. In field bioassays in Slovenia, traps baited with the synthesized pyrone captured both sexes of R. alpina, indicating that the pyrone functions as an aggregation pheromone. Our results represent the first example of a new structural class of pheromones within the Cerambycidae, and demonstrate that pheromone-baited traps can provide a useful tool for sampling R. alpina. This tool could be particularly useful in the ongoing development of conservation strategies for the iconic but endangered Alpine longicorn
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Suppression of HBV by Tenofovir in HBV/HIV coinfected patients : a systematic review and meta-analysis
Background: Hepatitis B coinfection is common in HIV-positive individuals and as antiretroviral therapy has made death due to AIDS less common, hepatitis has become increasingly important. Several drugs are available to treat hepatitis B. The most potent and the one with the lowest risk of resistance appears to be tenofovir (TDF). However there are several questions that remain unanswered regarding the use of TDF, including the proportion of patients that achieves suppression of HBV viral load and over what time, whether suppression is durable and whether prior treatment with other HBV-active drugs such as lamivudine, compromises the efficacy of TDF due to possible selection of resistant HBV strains.
Methods: A systematic review and meta-analysis following PRISMA guidelines and using multilevel mixed effects logistic regression, stratified by prior and/or concomitant use of lamivudine and/or emtricitabine.
Results: Data was available from 23 studies including 550 HBV/HIV coinfected patients treated with TDF. Follow up was for up to seven years but to ensure sufficient power the data analyses were limited to three years. The overall proportion achieving suppression of HBV replication was 57.4%, 79.0% and 85.6% at one, two and three years, respectively. No effect of prior or concomitant 3TC/FTC was shown. Virological rebound on TDF treatment was rare.
Interpretation: TDF suppresses HBV to undetectable levels in the majority of HBV/HIV coinfected patients with the proportion fully suppressed continuing to increase during continuous treatment. Prior treatment with 3TC/FTC does not compromise efficacy of TDF treatment. The use of combination treatment with 3TC/FTC offers no significant benefit over TDF alone
Worldwide tests of generic attractants, a promising tool for early detection of non-native cerambycid species
A large proportion of the insects which have invaded new regions and countries are emerging species, being found for the first time outside their native range. Being able to detect such species upon arrival at ports of entry before they establish in non-native countries is an urgent challenge. The deployment of traps baited with broad-spectrum semiochemical lures at ports-of-entry and other high-risk sites could be one such early detection tool. Rapid progress in the identification of semiochemicals for cerambycid beetles during the last 15 years has revealed that aggregation-sex pheromones and sex pheromones are often conserved at global levels for genera, tribes or subfamilies of the Cerambycidae. This possibly allows the development of generic attractants which attract multiple species simultaneously, especially when such pheromones are combined into blends. Here, we present the results of a worldwide field trial programme conducted during 2018-2021, using traps baited with a standardised 8-pheromone blend, usually com-plemented with plant volatiles. A total of 1308 traps were deployed at 302 sites covering simultaneously or sequentially 13 European countries, 10 Chinese provinces and some regions of the USA, Canada, Australia, Russia (Siberia) and the Caribbean (Martinique). We intended to test the following hypotheses: 1) if a species is regularly trapped in significant numbers by the blend on a continent, it increases the prob-ability that it can be detected when it arrives in other countries/continents and 2) if the blend exerts an effective, generic attraction to multiple species, it is likely that previously unknown and unexpected spe-cies can be captured due to the high degree of conservation of pheromone structures within related taxa. A total of 78,321 longhorned beetles were trapped, representing 376 species from eight subfamilies, with 84 species captured in numbers greater than 50 individuals. Captures comprised 60 tribes, with 10 tribes including more than nine species trapped on different continents. Some invasive species were captured in both the native and invaded continents. This demonstrates the potential of multipheromone lures as ef-fective tools for the detection of 'unexpected' cerambycid invaders, accidentally translocated outside their native ranges. Adding new pheromones with analogous well-conserved motifs is discussed, as well as the limitations of using such blends, especially for some cerambycid taxa which may be more attracted by the trap colour or other characteristics rather than to the chemical blend
Potential range of impact of an ecological trap network: the case of timber stacks and the Rosalia longicorn
Although the negative impact of timber stacks on populations of saproxylic beetles is a well-known phenomenon, there is
relatively little data concerning the scale of this impact and its spatial aspect. Beech timber stored in the vicinity of the forest
can act as an ecological trap for the Rosalia longicorn (Rosalia alpina), so in this study we have attempted to determine the
spatial range of the impact of a network of timber stacks. Timber stacks in the species’ range in the study area were listed
and monitored during the adult emergence period in 2014–2016. Based on published data relating to the species’ dispersal
capabilities, buffers of four radii (500, 1000, 1600, 3000 m) were delineated around the stacks and the calculated ranges of
potential impact. The results show that the percentage of currently known localities of the Rosalia longicorn impacted by
stacks varies from 19.7 to 81.6%, depending on the assumed impact radius. The percentage of forest influenced by timber
stacks was 77% for the largest-radius buffer. The overall impact of the ecological trap network is accelerated by fragmentation
of the impact-free area. It was also found that forests situated close to the timber stacks where the Rosalia longicorn was
recorded were older and more homogeneous in age and species composition than those around stacks where the species was
absent. Such results suggest that timber stacks act as an ecological trap in the source area of the local population
Novel, male-produced aggregation pheromone of the cerambycid beetle Rosalia alpina, a priority species of European conservation concern.
Several recent studies have demonstrated the great potential for exploiting semiochemicals in ecology and conservation studies. The cerambycid beetle Rosalia alpina represents one of the flagship species of saproxylic insect biodiversity in Europe. In recent years its populations appear to have declined substantially, and its range has shrunk considerably as a result of forest management and urbanization. Here, we collected volatile chemicals released by males and females of R. alpina. Analyses of the resulting extracts revealed the presence of a single male-specific compound, identified as a novel alkylated pyrone structure. In field bioassays in Slovenia, traps baited with the synthesized pyrone captured both sexes of R. alpina, indicating that the pyrone functions as an aggregation pheromone. Our results represent the first example of a new structural class of pheromones within the Cerambycidae, and demonstrate that pheromone-baited traps can provide a useful tool for sampling R. alpina. This tool could be particularly useful in the ongoing development of conservation strategies for the iconic but endangered Alpine longicorn
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