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Haberlea rhodopensis belongs to the small group of angiosperms that can survive desiccation to air-dry state and quickly restore their metabolism upon rehydration. In the present study, we investigated the accumulation of sHSPs and the extent of non-photochemical quenching during the downregulation of photosynthesis in H. rhodopensis leaves under desiccation at optimum (23 °C) and high temperature (38 °C). Desiccation of plants at 38 °C caused a stronger reduction in photosynthetic activity and corresponding enhancement in thermal energy dissipation. The accumulation of sHSPs was investigated by Western blot. While no expression of sHPSs was detected in the unstressed control sample, exposure of well-hydrated plants to high temperature induced an accumulation of sHSPs. Only a faint signal was observed at 50% RWC when dehydration was applied at 23 °C. Several cross-reacting polypeptide bands in the range of 16.5–19 kDa were observed in plants desiccated at high temperature. Two-dimensional electrophoresis and immunoblotting revealed the presence of several sHSPs with close molecular masses and pIs in the range of 5–8.0 that differed for each stage of treatment. At the latest stages of desiccation, fourteen different sHSPs could be distinguished, indicating that sHSPs might play a crucial role in H. rhodopensis under dehydration at high temperatures.

This paper reviews the recent development of the scientific, legislative, economic and environmental aspects of plant organic farming. The impact of organic farming on biodiversity and soil fertility is discussed in comparison with conventional systems. A significant barrier for wide application and future development of organic farming is the existing diversity of national and international policy instruments in this sector. Special attention is paid to up-to-date research techniques that could help solve a number of the problems typically faced in plant organic farming. It is argued that organic farming is still not productive enough to be considered fully sustainable. This underlines the necessity of strong support for more effective implementation of scientific research innovations and improvement of the networking between all stakeholders – organic producers, scientists and corresponding policy makers at the national and international level.

Haberlea rhodopensis (Gesneriaceae) belongs to the group of so-called resurrection plants, which are able to lose more than 95% of the water in the cells and quickly restore their metabolism upon rehydration. The plant is characterized with a high ecological plasticity growing at altitude from 136 m to near 1700 m at different temperature, water, and light conditions. In its natural habitats, H. rhodopensis is often exposed to high temperatures during dry periods in the summer. In the present study, we investigated the accumulation of small heat shock proteins (sHSPs) and the extent of non-photochemical quenching during the downregulation of photosynthesis in H. rhodopensis under desiccation at optimum (23 °C) and high temperature (38 °C). Dehydration at high temperature has a detrimental effect on plant photosynthesis, thus leading to oxidative stress and damage of different important macromolecules in the cells. Plants accumulate different protective proteins when exposed to high temperatures, one of the most characteristic being sHSPs. They prevent irreversible aggregation of unfolded or aggregated proteins and facilitate their refolding. Plants possess more than 30 different of sHSPs, much more compared to mammals and microorganisms. Fourteen different isoforms of sHSPs accumulate during dehydration at 38 °C compared to 23 °C, where only two were detected. H. rhodopensis is an excellent model system to study the protective mechanisms under extreme dehydration at high temperature, thus helping plant breeders to create high temperature resistant crops.

The significance of Canine parvovirus 2 (CPV-2) infection for the domesticated canides is well understood. The current study compares the morbidity rate and clinical outcome in a group of vaccinated and non-vaccinated dogs (11 and 27 individuals, respectively) presented for treatment between October 2009 and March 2011. Fecal samples from the dogs with clinical signs of Canine Parvovirosis (CPV) were tested using a rapid test based on detection of CPV antigens, and a polymerase chain reaction (PCR) was applied for detection of viral DNA. For further confirmation two of the positive samples were sequenced, and after alignment with the Basic Local Alignment Search Tool (BLAST) they showed over 99% of overlapping with the data in GenBank. There wasn't significant difference in morbidity between vaccinated and nonvaccinated dogs, but the recovery period was shorter for the first group (mean value 7 days+/-1d, versus 12 days+/-2d). Some of the dogs were vaccinated twice or even thrice, but fail to resist, which might be due to an inadequate vaccination scheme or vaccine, or an early exposure to the wild virus. The latter suggests the increasing need of a modern diagnostic approach, for discrimination between the wild virus and the strains used for vaccination.

Exponential-phase cell cultures from Antarctic and mesophilic strains of the cyanobacterium Synechocystis salina and the unicellular green alga Chlorella vulgaris were subjected to UV-B and temperature stress and investigated for alterations in the spectrum of secreted proteins. In addition to constitutively secreted proteins, strain-specific stress proteins were detected on silver-stained gels. Extracellular protein patterns within a given strain, as well as between strains after exposure to each UV-B and temperature stress were notably different. UV-B exposure induced only moderate changes of the secreted proteins in both Antarctic and mesophilic Synechocystis salina strains. However, a 21 kDa protein band present in Antarctic Synechocystis salina only was identified using LC-MS/MS analysis, to contain two proteins-a peroxiredoxin and Fe-superoxide dismutase (Fe-SOD). Their presence might modulate the level of reactive oxygen species generated in membranes during UV-B stress and, thus, contribute to the higher survival rate of Antarctic Synechocystis salina. In addition, proteolytic activity in the extracellular protein samples of both species was detected on 1D zymography in a polyacrylamide gel containing gelatin as substrate. Antarctic Synechocystis salina secreted cysteine-, serine-, and metalloproteases, while mesophilic Synechocystis salina secreted mainly cysteine proteases. Subtle changes of the protease activity bands in Antarctic Synechocystis salina and Chlorella vulgaris were observed after UV-B and temperature stress. In contrast, mesophilic Synechocystis salina responded with a considerable increase in protease activity and number of activity bands after 30 min and 60 min exposure to UV-B, as well as when grown at 35°C and 40°C. Peptidases are key players in structuring and adapting cells under various stressful conditions. The varying pattern of secreted proteases among the Antarctic and mesophilic strains of Synechocystis salina and Chlorella vulgaris suggests different mechanisms for coping with UV-B and temperature stress. Characterization of extracellular proteins discovered in the present study will provide further understanding of the rich defense arsenal and mechanisms of survival of cyanobacteria and microalgae.

Somatic embryogenesis is a unique phenomenon in the plant kingdom and involves the transition of somatic cells into cells that are capable of forming an embryo. Proteins secreted into the medium of suspension cell cultures play an important role by either promoting or inhibiting embryo development. A monoclonal antibody MAb 3G2 raised against extracellular proteins from orchardgrass (Dactylis glomerata L.) embryogenic suspension culture recognized specifically a 48 kD protein with pI 5.2 (designated EP48) from the cell wall and culture medium of microclusters, which could serve as an early marker for embryogenic potential in D. glomerata cultures [Tchorbadjieva M., Kalmukova R., Pantchev I., Kyurkchiev S. 2005. Planta, 222, 811-819]. In this study, in-gel trypsin digestion of EP48 separated by 2-D gel electrophoresis and LC-MS/MS mass spectrometry identified the protein as α-amylase. The full-length cDNA encoding D. glomerata L. α-amylase (designated DgAmy1, GenBank accession number GU 067465.1) was cloned by rapid amplification of cDNA ends (RACE) and was shown to contain an open reading frame of 1284 bp encoding α-amylase protein of 427 amino acids with a calculated molecular mass of the mature protein of 44.742 kDa and pI of 5.12. Comparative analysis showed that DgAmy1 shares an overall identity of 59-89% with α-amylases from other plant species, and is most closely related to that of barley (Hordeum vulgare). Homology modeling using barley α-amylase Amy2 as a template revealed that DgAmy1 contains three domains (A, B, C) and active sites that are common with other plant α-amylases. However, it lacks the substrate binding sites 1 and 2 typical for cereal α-amylases. The recombinant DgAmy1 expressed in E. coli BL21 (DE3) and purified by Ni 2+ Sepharose was biologically active as revealed by activity zymography using soluble starch as a substrate. The high yield (200 mg protein from 1 L culture medium) and purity (99%) of the recombinant DgAmy1 will be helpful for further understanding of the structure/function correlations and especially the role that this extracellular α-amylase plays at early stages of somatic embryogenesis.