Studies on the composition of the extracellular fluid from calf costal cartilage

Appreciable amounts of free and bound hydroxyproline were found in the tissue fluid obtained by centrifugation from calf costal cartilage. In the tissue fluid the presence of an enzyme capable of splitting synthetic collagenase substrate at pH 7.4 and 37° was also demonstrated. The enzyme has been partially purified by (NH₄₂SO₄ saturation. Peak activity was obtained in the fraction of 50–60% saturation. The enzyme was not capable of degrading insoluble bovine. Achilles tendon collagen. In our opinion the enzyme cannot be considered a collagenase, and we call its activity “collagenase-like peptidase activity”.     

Stimulation of thaumarchaeal ammonia oxidation by ammonia derived from organic nitrogen but not added inorganic nitrogen

Ammonia oxidation, the first step in nitrification, is performed by autotrophic bacteria and thaumarchaea, whose relative contributions vary in different soils. Distinctive environmental niches for the two groups have not been identified, but evidence from previous studies suggests that activity of thaumarchaea, unlike that of bacterial ammonia oxidizers, is unaffected by addition of inorganic N fertilizer and that they preferentially utilize ammonia generated from the mineralization of organic N. This hypothesis was tested by determining the influence of both inorganic and organic N sources on nitrification rate and ammonia oxidizer growth and community structure in microcosms containing acidic, forest soil in which ammonia oxidation was dominated by thaumarchaea. Nitrification rate was unaffected by the incubation of soil with inorganic ammonium but was significantly stimulated by the addition of organic N. Oxidation of ammonia generated from native soil organic matter or added organic N, but not added inorganic N, was accompanied by increases in abundance of the thaumarchaeal amoA gene, a functional gene for ammonia oxidation, but changes in community structure were not observed. Bacterial amoA genes could not be detected. Ammonia oxidation was completely inhibited by 0.01% acetylene in all treatments, indicating ammonia monooxygenase-dependent activity. The findings have implications for current models of soil nitrification and for nitrification control strategies to minimize fertilizer loss and nitrous oxide production.     

The DNA-B of the non-phloem-limited bean dwarf mosaic virus (BDMV) is able to move the phloem-limited Abutilon mosaic virus (AbMV) out of the phloem,but DNA-B of AbMV is unable to confine BDMV to the phloem

Abutilon mosaic virus (AbMV) and bean dwarf mosaic virus (BDMV) are two phylogenetically related bipartite begomoviruses. While AbMV is restricted to phloem, BDMV spreads to non-phloem tissues. Cell-to-cell and long-distance movement of AbMV and BDMV were investigated after replacing the coat protein (CP) gene with the reporter gene encoding the green fluorescence protein (GFP). The DNA-A and DNA-B genomic components of AbMV and BDMV, and their pseudorecombinants (PR), were delivered to bean (Phaseolus vulgaris) seedlings and detached leaves with DNA-coated microprojectiles. Virus-associated fluorescence was observed with the confocal microscope. Delivery of AbMV and BDMV GFP reporters showed that the epidermal tissue was the main recipient of the viral DNA; the DNA-A of the two viruses was unable to move out of the recipient cells. AbMV DNA-A co-inoculated with AbMV DNA-B did not move from cell to cell in the epidermis and did not reach the phloem. However, co-inoculation of AbMV DNA-A with BDMV DNA-B resulted in PR cell-to-cell movement out of the epidermis and long-distance movement in the phloem. In contrast, BDMV DNA-A moved from cell to cell and over a long distance when co-inoculated with either its own DNA-B or with the DNA-B of AbMV. Thus, the DNA-B of the non-phloem-limited BDMV overcame the phloem limitation of AbMV. In the reciprocal case, the DNA-B of the phloem-limited AbMV did not confine the non-phloem limited BDMV to the phloem. Hence, we assume that the DNA-A component of BDMV includes determinants involved in the movement pattern of the virus in addition to the DNA-B-encoded BC1 and BV1 which have previously been shown to be involved in virus movement. The results also confirm that the CP is not necessary for virus movement; however, replacing the CP of AbMV and BDMV with GFP resulted in a decrease in symptom severity. DNA-B was involved in symptom severity; the B component of BDMV produced symptoms more severe than those induced by that of AbMV, whether in wild-type PRs or in PRs with CP-GFP replacement. It is interesting to note that when the GFP gene under the control of the CaMV 35S promoter (35S-GFP) was delivered to the bean tissue, with or without the DNA-B component of BDMV, GFP was expressed but did not move from cell to cell. However, when the 35S-GFP was delivered together with BDMV DNA-A and DNA-B, GFP showed cell-to-cell movement in the epidermis but was restricted to these cells. Hence, infection of cells with a functional bipartite begomovirus may facilitate cell-to-cell movement of macromolecules.     

Can chicken and human PrPs possess SOD-like activity after beta-cleavage?

The prion protein is a membrane attached glycoprotein that is involved in binding of divalent copper ions. In vivo human and chicken PrPs exhibit SOD-like activity associated with octarepeat and hexarepeat regions, respectively, when bind Cu(II) ions. However, the species of Cu(II)-PrP involved in the Cu(II) center which determines the highest SOD-like activity is still unknown. The data presented here clearly show that the single Cu(II) ion bound to PrP octapeptide repeat region of mammalian prion and hexapeptide repeat region of avian prion via 4 His side-chain imidazoles reveals the highest SOD activity.     

Fusion of oil bodies in endosperm of oat grains

Few microscopical studies have been made on lipid storage in oat grains, with variable results as to the extent of lipid accumulation in the starchy endosperm. Grains of medium- and high-lipid oat (Avena sativa L.) were studied at two developmental stages and at maturity, by light microscopy using different staining methods, and by scanning and transmission electron microscopy. Discrete oil bodies occurred in the aleurone layer, scutellum and embryo. In contrast, oil bodies in the starchy endosperm often had diffuse boundaries and fused with each other and with protein vacuoles during grain development, forming a continuous oil matrix between the protein and starch components. The different microscopical methods were confirmative to each other regarding the coalescence of oil bodies, a phenomenon probably correlated with the reduced amount of oil-body associated proteins in the endosperm. This was supported experimentally by SDS-PAGE separation of oil-body proteins and immunoblotting and immunolocalization with antibodies against a 16 kD oil-body protein. Much more oil-body proteins per amount of oil occurred in the embryo and scutellum than in the endosperm. Immunolocalization of 14 and 16 kD oil-body associated proteins on sectioned grains resulted in more heavy labeling of the embryo, scutellum and aleurone layer than the rest of the endosperm. Observations on the appearance of oil bodies at an early stage of development pertain to the prevailing hypotheses of oil-body biogenesis.     

<Emphasis Type="Italic">Apodemus</Emphasis> mice as the main prey that determines reproductive output of tawny owl (<Emphasis Type="Italic">Strix aluco</Emphasis>) in Central Europe

During the years 2008–2014, we studied diet composition, the number of breeding pairs, and reproductive output of tawny owls in Central Europe (Czech Republic) in relation to availability of main prey in the field. We also performed a meta-analysis on diet composition of tawny owl in Europe that confirmed the important role of Apodemus mice in tawny owl diet in Central Europe. In concordance, Apodemus mice were the main prey of tawny owl in our study area (38.7%), and Microtus/Myodes voles (15.4%), birds (12.1%) and others (33.8%) were alternative prey. We found a positive relationship between the proportion of Apodemus mice in the diet and their abundance in the field (beta = 0.23, P = 0.001). Availability of main prey (Apodemus mice, Microtus/Myodes voles or Sorex shrews) in the field was not correlated with the number of breeding pairs. Proportion of birds in diet (expressed by scores from multivariate analysis), which was inversely related to proportion of Apodemus mice, was positively correlated with laying date (beta = 0.66, P = 0.012) and negatively correlated with clutch size (beta = − 0.45, P = 0.004) and brood size (beta = − 0.16, P = 0.076). We also found negative relationships between laying date and clutch size (beta = − 0.13, P = 0.014) and brood size (beta = − 0.07, P = 0.057). Our results support the idea that diet and breeding ecology of owls in Central Europe is mainly driven by the availability of Apodemus mice that are suitable prey due to their similar habitat requirements and nocturnal activity.     

Low temperature seed germination of several tomato genotypes

Environmental stresses at particularly vulnerable stages during crop development may severely diminish productivity. At temperature of 10 °C or below cultivated tomato germinate slowly if at all. In this study, seven tomato genotypes bred at the Research Institute of Vegetable Crops were evaluated for germination time at 10 °C. Analysis identified that one genotype which has L. chilense in its pedigree, germinated most rapidly while four other genotypes germinated slower. After 21 days, four out of five of the genotypes resulted in seed germination from 81 to 98 %.