Encapsulation of Carlina acaulis essential oil and carlina oxide to develop long-lasting mosquito larvicides: microemulsions versus nanoemulsions

Journal of Pest Science - Carlina acaulis root essential oil (EO) is one of the most potent mosquito larvicides (LC50?<?2 ppm). This EO is mainly composed of carlina...     

Growth and wood density of Pinus taeda L. as affected by shelterwood harvest in a two-aged stand in Southern Brazil

Pine plantations are an important wood source in Brazil, with Pinus taeda being most frequently planted. Most pinewood is directed to the paper and pulp industry, but there is an increasing demand for wood for solid end-uses, requiring large stems from longer rotations which can be obtained using P. taeda as the canopy in two-aged stands. We evaluated radial growth and wood density at different stem heights of P. taeda in the highlands of Southern Brazil over a production period of 36 years and subjected to shelterwood harvest. Cross-sectional disks were obtained from 15 trees in different stem heights; 10 were used for growth analyses and 5 for growth and density analyses. We used disk images and X-ray techniques for growth and density analyses, respectively. Samples were analyzed for ring (width and density), earlywood, and latewood (width, density, and proportion). Ring width varied between 0.4 and 1.7 cm, with the widest rings in the first years (3–5 years.) of growth. Ring density increased with age, with higher densities on the lower stem portions. Mature wood started to be formed from the 16th ring onwards. Shelterwood harvest affected both ring width and density, but the effects on ring width lasted for at least 5 years, while the effects on wood density were short-lasting. Mature P. taeda trees increased their size after the shelterwood harvest without compromising their wood density. Longer production periods of P. taeda as retained trees in the canopy of two-aged stands provide high-quality wood for structural purposes.

     

Successful treatment of small intestinal volvulus in two cats

BACKGROUND: Mesenteric volvulus describes a torsion of the small intestine around the mesenteric root, which can be partial or complete. In dogs, it is an uncommon condition, with German shepherd dogs showing a predisposition. Chronic mesenteric volvulus has also been described. In cats, previous reports have documented two cases of small intestinal volvulus, both diagnosed at necropsy, and a further case of volvulus of the colon in a patient that died after surgery. CLINICAL SIGNIFICANCE: This report describes two cats with mesenteric volvulus that were successfully treated. To the authors' knowledge, no reports of antemortem diagnosis or treatment of small intestinal volvulus in cats have previously been published. On the basis of the cases presented, it appears that the diagnosis of intestinal volvulus may be more difficult in cats than in dogs, but that the prognosis may not be as poor. Therefore, it is suggested that owners be encouraged to pursue surgery.     

Conventional PCR and real time quantitative PCR detection of <Emphasis Type="Italic">Phytophthora cryptogea</Emphasis> on <Emphasis Type="Italic">Gerbera jamesonii</Emphasis>

A conventional PCR and a SYBR Green real-time PCR assays for the detection and quantification of Phytophthora cryptogea, an economically important pathogen, have been developed and tested. A conventional primer set (Cryp1 and Cryp2) was designed from the Ypt1 gene of P. cryptogea. A 369 bp product was amplified on DNA from 17 isolates of P. cryptogea. No product was amplified on DNA from 34 other Phytophthora spp., water moulds, true fungi and bacteria. In addition, Cryp1/Cryp2 primers were successfully adapted to real-time PCR. The conventional PCR and real-time PCR assays were compared. The PCR was able to detect the pathogen on naturally infected gerbera plants and on symptomatic artificially infected plants collected 21 days after pathogen inoculation. The detection limit was 5 × 10³ P. cryptogea zoospores and 16 fg of DNA. Real-time PCR showed a detection limit 100 times lower (50 zoospores, 160 ag of DNA) and the possibility of detecting the pathogen in symptomless artificially infected plants and in the re-circulating nutrient solution of closed soilless cultivation systems.     

Large reservoirs as ecological barriers to downstream movements of Neotropical migratory fish

Most large rivers in South America are fragmented by large dams, and a common management strategy to mitigate impacts has been construction of fish passes. Recent studies, however, indicate that downstream passage of adults and young fish is nil or minimal. Better understanding of this phenomenon is needed if fishways are to provide any tangible conservation value in South America. We propose, in this article, that large reservoirs impose a different kind of barrier to migrating fish: impoundments create a diffuse gradient of hydraulic/limnological conditions that affects fish behaviour and functions as an extensive environmental filter that discourages downstream movements. To develop this idea, we characterize the barriers created by dams and reservoirs by describing their distinct nature, the effects on fish migration and potential solutions. We show, for example, that dams generally prevent upstream movements, whereas reservoirs impede mainly downstream movements. In this context, we explain how fish passes, in some instances, can partially mitigate fragmentation caused by dams, but there is no technical solution to solve the barrier effect of reservoirs. In addition, we present a body of empirical evidence that supports the theory that large reservoirs are important barriers to fish migration in South America, we offer an overview of the size of reservoirs to show that impoundments typically have large dimensions, and we discuss the significance of this theory for other regions. Based on current and proposed river regulation scenarios, we conclude that conservation of Neotropical migratory fish will be much more complicated than previously believed.     

An index of human alteration of lake shore morphology

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Larval population structure of Engraulis encrasicolus in the Strait of Sicily as revealed by morphometric and genetic analysis

In order to investigate the larval population structure, specimens of Engraulis encrasicolus larvae from five different locations in the Strait of Sicily were analyzed by means of otolith readings, morphometric and genetic techniques. The distribution of age in day, identified by means of the otolith readings and associated with the oceanographic parameters, was useful to identify possible spawning areas and transport dynamics. The presence of more than one spawning area suggested the possibility that two or more sub‐populations may co‐exist in the study area. The morphometric characteristics were more adequate than genetic parameters to discriminate the different larval groups. The most relevant variables for the separation were the mouth length (ML) and the body diameter (BD). The population structure by means of genetic data reported the presence of two phylogroups co‐occurring among samples in each sampling locations specimens. The pattern of genetic divergence among anchovy larvae in the Strait of Sicily was congruent with previous studies conducted on adult populations present in other Mediterranean areas with different molecular markers. The habitat‐specific nature of the morphological variation and the lack of corresponding genetic variation among larvae from the different locations suggested that the observed differences in morphology could be linked to environmental parameters. The body form differences among different larvae samples could reflect the nutritional status of larvae. In fact, these differences were found among anchovy larvae collected in areas with different oxygen and fluorescence, which is an index of primary productivity and is linked to the availability of food for anchovy larvae.