Identification of the causal agents of crazy root disease on hydroponically cultivated cucumber plants in Poland

European Journal of Plant Pathology - In April 2019, hydroponically cultivated cucumber plants with characteristic symptoms of crazy root disease were found in two different commercial production...     

Nutritive defaunation of the rumen in steers with subsequent refaunation using a cryopreserved monoculture of Entodinium caudatum

This study evaluated a technique for the nutritive defaunation of the rumen of cattle with subsequent single species refaunation using a cryopreserved monoculture of Entodinium caudatum (family Ophryoscolecidae). Four mature steers were nutritionally defaunated in two periods using two steers in each period. A diet containing (dry matter basis) 68% ground wheat grain, 7% wheat bran, 8% soybean oil and 17% wheat straw was used to decrease the pH of ruminal contents and to eliminate rumen ciliate protozoa. Protozoa‐free rumens were observed on day 8 and 9 in the first and second period, respectively, after the start of defaunation. A monoculture of E. caudatum (34/89/94) was transported from the Institute of Animal Physiology, Slovak Academy of Sciences in Ko?ice to the University of Kiel (Germany) in liquid nitrogen in October 1996. The inoculation was accomplished on day 15 in the second period by applying 30 ml culture medium with a monoculture of E. caudatum (34/89/94; average concentration of protozoal cells 2 650/ml) into the rumen of a defaunated steer via the ruminal fistula. The mono‐faunated steer was successfully inoculated with an average concentration of E. caudatum cells at 4.1 × 10³/ml (SD = 0.2) on day 2 after the inoculation.     

Tree reactions and dune movements: Slowinski National Park,Poland

The effects on tree growth of both climatic and non-climatic variables were investigated in relation to dune dynamics at three sites on the Czolpinska dune in the Slowinski National Park, Poland where aeolian sediments are invading a forest of Scots Pine (Pinus sylvestris L.). We found that where dune advance was relatively rapid, tree vitality declined after stem burial was over 1.9 m, but where advance was under 1 m/yr survival was remarkably increased, one tree survived, albeit with thinning needles, after an estimated 11.4 m burial. Below sand-surface stem discs, cut 0.5 m apart, from a heavily suppressed tree revealed a difference in narrow-ring reactions of up to 2 years over a 2 m burial distance; the discs also showed a time lag of 4 years before compression wood formation. Consequently, when estimating sand-movement rates we discounted compression wood reactions; we also excluded climatic events and pest infestations. The remaining data supplied a sand-advance rate at Site 1 from 2.4 to 3.5 m/yr. At Site 2, rates were from 1.2 to 2.5 m/yr, with a direct measurement of 0.3 m/yr between 2006 and 2007. At Site 3 rates were from 0.3 to 1.2 m/yr, with dune migration here virtually at a standstill over the last seven years. Direct measurement of sand movement (3.03 m/yr) at Site 1 was slower than the lowest rate (3.5 m/yr) previously recorded by Borówka (1980) for the larger dune system.     

Electrostatic self-assembly of binary nanoparticle crystals with a diamond-like lattice

Self-assembly of charged, equally sized metal nanoparticles of two types (gold and silver) leads to the formation of large, sphalerite (diamond-like) crystals, in which each nanoparticle has four oppositely charged neighbors. Formation of these non-close-packed structures is a consequence of electrostatic effects specific to the nanoscale, where the thickness of the screening layer is commensurate with the dimensions of the assembling objects. Because of electrostatic stabilization of larger crystallizing particles by smaller ones, better-quality crystals can be obtained from more polydisperse nanoparticle solutions.     

Antioxidant capacity manipulation in transgenic potato tuber by changes in phenolic compounds content

The main goal of this study was to generate potato tubers with increased levels of flavonoids and thus modified antioxidant capacities. To accomplish this, the vector carrying multigene construct was prepared and several transgenic plants were generated, all overexpressing key biosynthesis pathway enzymes. The single-gene overexpression or simultaneous expression of genes encoding chalcone synthase (CHS), chalcone isomerase (CHI), and dihydroflavonol reductase (DFR) resulted in a significant increase of measured phenolic acids and anthocyanins. The increase in phenolic compounds synthesis is accompanied by decreases in starch and glucose levels in transgenic plants. The flavonoids-enriched plants showed improved antioxidant capacity; however, there is a complex relationship between antioxidant capacity and flavonoids content, suggesting the great participation of other compounds in the antioxidant potential of the plants. These other compounds are not yet recognized.     

Community structure of Lumbricidae in beech woodland of the Bieszczady National Park, Southeast Poland

As ecosystem engineers, earthworms play a key role in the soil environment. However, due to increasing anthropogenic pressure, soil organisms,including earthworms, are being threatened by habitat loss. In this study, we undertook a qualitative and quantitative investigation of earthworms of the family Lumbricidae in four types of Carpathian beech woodland(Fagetum carpaticum), characterized by their understory vegetation(I, F. c. festucetosum drymejae; II, F. c. typicum; III, F. c. lunarietosum; and IV, F. c. allietosum), in the Bieszczady National Park(Eastern Carpathians, Southeast Poland). At each investigated site, soil monoliths(25 cm × 25 cm × 25 cm) were examined by hand sorting. Earthworms were expelled from deep soil layers using a weak formalin solution(0.4%). Depending on the phytocoenosis, 7 species of Lumbricidae were identified at each of the sites I, II, and III and 10 at site IV. Site IV(F. c. allietosum) differed significantly(P 0.05) from the other three sites with respect to earthworm biomass(59.71 ± 39.53 g m~(-2))and the Shannon-Wiener diversity index(0.52 ± 0.12). Although present three decades ago, the deep-burrowing species Octodrilus transpadanus and the litter-dwelling species Dendrobaena octaedra were not found at site IV in the present study. We suspect that these two species may have been displaced by the invasive Lumbricus terrestris, which was not found at the same site in the 1980 s. Such observations warrant further investigation to verify the predicted effects of an invasive earthworm, including the potential effects on soils and other fauna and flora, which have been documented in numerous countries.     

Plastic and moldable metals by self-assembly of sticky nanoparticle aggregates

Deformable, spherical aggregates of metal nanoparticles connected by long-chain dithiol ligands self-assemble into nanostructured materials of macroscopic dimensions. These materials are plastic and moldable against arbitrarily shaped masters and can be thermally hardened into polycrystalline metal structures of controllable porosity. In addition, in both plastic and hardened states, the assemblies are electrically conductive and exhibit Ohmic characteristics down to approximately 20 volts per meter. The self-assembly method leading to such materials is applicable both to pure metals and to bimetallic structures of various elemental compositions.