Ophiostomatoid fungi associated with three spruce-infesting bark beetles in Slovenia

Context

Ophiostomatoid fungi can severely affect the health and economic value of Norway spruce trees (Picea abies). Although the diversity of ophiostomatoid species and their associations with insects have been well-investigated in central and northern Europe, little is known about the conditions in south-eastern Europe.

Aim

This study aims to study the assemblages of ophiostomatoid fungi associated with three bark beetle species (Ips typographus, Ips amitinus, and Pityogenes chalcographus) that infect Norway spruce in Slovenia.

Methods

Bark beetles were sampled in four phytogeographic regions in Slovenia. The fungi found on the bark beetles were identified based on morphology, DNA sequence comparisons of ITS regions and phylogenetic analysis. The species compositions of the fungal associates of the three insect species were compared and the pairwise associations of the occurrence of the fungal species were analysed.

Results

Thirteen different species were found. The most commonly encountered fungal associates of the beetles were Ophiostoma bicolor, Ophiostoma brunneo-ciliatum, Grosmannia piceiperda, Ophiostoma ainoae, Ceratocystiopsis minuta, and Grosmannia penicillata. The composition of the fungal associates differed among the bark beetle species, but not among the phytogeographic regions.

Conclusions

This study confirms that ophiostomatoid species are common associates of the investigated bark beetle species. Many ophiostomatoid species have strong host associations. I. typographus and P. chalcographus can act as effective vectors for O. bicolor, O. ainoae, G. piceiperda and O. brunneo-ciliatum, whereas I. amitinus often carries G. piceiperda and C. minuta in Slovenian forests.     

Cellular-resolution in vivo imaging of the feline retina using adaptive optics: preliminary results

Purpose To perform cellular‐level in vivo imaging of the feline retina using an adaptive optics flood illumination fundus camera (AO FIFC) designed for the human eye. Materials and methods Cellular‐level images were obtained from three eyes of two normal sedated cats. Ocular aberrations were corrected using an AO system based on a 52‐acuator electromagnetic deformable mirror and a 1024 lenslet Hartmann–Shack sensor (both Imagine Eyes, Orsay, France). A square 3°×3° area of the ocular fundus was flood‐illuminated by a pulsed LED emitting at 850 nm and imaged onto a low‐noise, high‐resolution CCD camera. The animal’s pupils were dilated and the effective pupil size was set to 7.5 mm. Conjunctival atraumatic clips were used to avoid eyeball movements and eyelid closure. The cornea was artificially hydrated throughout the experiments. Each acquisition consisted of 20 consecutive images, out of which 10 were numerically averaged to produce an enhanced final image. Results The total amount of ocular aberrations was greatly reduced by the AO correction, from 2.4 to 0.21 microns root mean square on average. The resulting images presented white dots distributed at a density similar to that of cone photoreceptors and they allowed us to visualize small blood vessels and nerve fiber bundles at a higher resolution than classically obtained with conventional fundus photography. Conclusion Retinal imaging with cellular resolution was feasible in cats under sedation using an AO FIFC designed for human eyes without any optical modification. The AO FIFC technology could find new applications in clinical, pharmacological, and toxicological investigations.     

Bacterial Exopolysaccharides from Extreme Marine Habitats: Production,Characterization and Biological Activities

Many marine bacteria produce exopolysaccharides (EPS) as a strategy for growth, adhering to solid surfaces, and to survive adverse conditions. There is growing interest in isolating new EPS producing bacteria from marine environments, particularly from extreme marine environments such as deep-sea hydrothermal vents characterized by high pressure and temperature and heavy metal presence. Marine EPS-producing microorganisms have been also isolated from several extreme niches such as the cold marine environments typically of Arctic and Antarctic sea ice, characterized by low temperature and low nutrient concentration, and the hypersaline marine environment found in a wide variety of aquatic and terrestrial ecosystems such as salt lakes and salterns. Most of their EPSs are heteropolysaccharides containing three or four different monosaccharides arranged in groups of 10 or less to form the repeating units. These polymers are often linear with an average molecular weight ranging from 1 × 10⁵ to 3 × 10⁵ Da. Some EPS are neutral macromolecules, but the majority of them are polyanionic for the presence of uronic acids or ketal-linked pyruvate or inorganic residues such as phosphate or sulfate. EPSs, forming a layer surrounding the cell, provide an effective protection against high or low temperature and salinity, or against possible predators. By examining their structure and chemical-physical characteristics it is possible to gain insight into their commercial application, and they are employed in several industries. Indeed EPSs produced by microorganisms from extreme habitats show biotechnological promise ranging from pharmaceutical industries, for their immunomodulatory and antiviral effects, bone regeneration and cicatrizing capacity, to food-processing industries for their peculiar gelling and thickening properties. Moreover, some EPSs are employed as biosurfactants and in detoxification mechanisms of petrochemical oil-polluted areas. The aim of this paper is to give an overview of current knowledge on EPSs produced by marine bacteria including symbiotic marine EPS-producing bacteria isolated from some marine annelid worms that live in extreme niches.     

Inferred origin of several Native American potatoes from the Pacific Northwest and Southeast Alaska using SSR markers

Certain Native Americans from the Pacific Northwest and Alaska of the USA have grown potatoes in their gardens for many generations. In this study, the origin of several potatoes collected from Native gardens was investigated. Fourteen SSR markers covering the 12 potato homologs yielding a total of 199 alleles were amplified and scored in Solanum tuberosum Group Andigena (52 accessions), S. tuberosum Group. Tuberosum (39 accessions) and wild species (6 accessions). “Ozette” from the Makah Nation on the Olympic Peninsula in Washington State was closely related to “Maria’s” and “Kasaan” potatoes collected from Native Alaskan gardens in Southeast Alaska. These three potatoes were more closely related to either two Mexican and one Peruvian andigena accessions or three Chilean Group Tuberosum accessions, while being relatively less related to the old European or modern varieties and most distantly related to Group Andigenum. “To-Le-Ak” was closely related to two Chilean tuberosum accessions and one old European variety. All Native potatoes harbored T-type chloroplast genome indicating that their maternal lineage is shared with Chilean Group Tuberosum. Using genetic relationship as a guide to origin it appears plausible that the Native American/Alaskan cultivars are either directly or indirectly from Mexico and Chile. These Native potato cultivars present a possible second route of diffusion distinct from the South America to Europe transfer which has been assumed to the sole means by which potato was spread out of South America.     

A novel method for monitoring real-time curing behaviour

A new method for monitoring real-time curing behaviour of adhesives by means of a rheometer is presented. This method was developed within a study to characterize the curing behaviour of MUF adhesives on beech and ash, both with and without coloured heartwood, as well as on Douglas fir and spruce. During closed assembly time, the decrease in a predefined adhesive layer, caused by the penetration of adhesive and solvents into the wood, can be monitored. Furthermore, the progress of curing can be determined and assessed after predefined closed assembly times. The maximum tensile force and the dissipated energy required for separating assembled adherends allow for characterizing hardening of adhesive systems. First results suggest that this is a promising method contributing to a better understanding of the curing process and how it is influenced by wood species.     

How do trees affect spatio-temporal heterogeneity of nutrient cycling in mediterranean annual grasslands?

? In this study we analyzed heterogeneity in nutrient cycling induced by trees in Mediterranean annual grasslands, comparing years of higher and lower than average precipitation and analyzing the effects of two different solar radiation scenarios.

? Organic matter and consequently upper soil N, K, Ca and Mg were significantly greater in those locations receiving the highest levels of solar radiation, and as expected from many other studies in the literature, there was an increase in all macronutrients (except P) as well as pH below the canopy.

? Contrary to what was expected, plant nutrient concentrations did not directly reflect those found in the soil, with the exception of K. The studied grassland responded to increased nutrient availability by enhancing growth and changing botanical composition rather than by increasing plant nutrient concentrations. Hence, the total amount of accumulated nutrients in the ecosystem was larger below the tree than outside it, although this is mainly a consequence of plant growth enhancement. The levels of Ca, Mg, and Na in plants decreased during the driest year, and the N content was mostly determined by the composition of the grass.

? Temporal nutrient variability, particularly within-years, explained most of the variability in plant nutrient concentration, while spatial variability induced by trees was determined to be of secondary importance. These results are significant for ecosystem nutrient modelling.

     

A comparison of different methods for forest resource estimation using information from airborne laser scanning and CIR orthophotos

This article compares three methods for forest resource estimation based on remote sensing features extracted from Airborne laser scanning and CIR orthophotos. The estimation was made exemplarily for the total stem volume of trees for a given area, measured in cubic metres per hectare [m3 ha⁻¹] (as one of the most important quantitative parameters to characterise a forest stand). The following methods were compared: Regression Analysis (RA), k-NN (nearest neighbour) method and a method that utilises regional yield tables, referred to as the yield table method (YT-method). The estimation of stem volume was examined in a mixed forest in Southern Germany using 300 circular inventory plots, each with a size of 452 m2. Remote sensing features relating to vegetation height and structures were extracted and used as input variables in the different approaches. The accuracy of the estimation was analysed using scatter plots and quantified using absolute and relative root mean square errors (RMSE). The comparison was made for all plots, as well as for averaged plot values located within forest stands that have the same age class. On “plot level” the RMSE yielded 79.79 m3 ha⁻¹ (RA), 81.93 m3 ha⁻¹ (k-NN) and 81.78 m3 ha⁻¹ (YT-method) and for the averaged values 35.75 m3 ha⁻¹ (RA), 35.06 m3 ha⁻¹ (k-NN) and 42.98 m3 ha⁻¹ (YT-method). Advantages and disadvantages, as well as requirements, of the methods are discussed.     

Opinion paper: Effects of simulated soil temperature on stem diameter increment of <Emphasis Type="Italic">Pinus cembra</Emphasis> at the alpine timberline: a new approach based on root zone roofing

For assessing the impact of soil temperature on tree growth in remote areas such as the alpine timberline, we introduce a new method for soil temperature manipulations. This new approach is based on roofing of the rooting zone and allows either soil cooling or soil warming without significantly influencing soil water availability and the above ground microclimate.     

饲用胆碱对奶牛能量及健康状况的影响

<正>奶牛肝脏的能量代谢效率影响其能量平衡和营养状况,日粮中添加适量的胆碱有利维护奶牛肝脏的正常功能,从而支撑其能量营养、繁殖、产奶及健康。例如在围产期,若奶牛肝功正常,则其与能量相关的疾病(如:酮症、子宫炎、皱胃移位和乳房炎等)