Production of extracellular lipase by the hexachlorocyclohexane utilizing Pseudomonas strain Ptm+

Extracelluar lipase activity was detected in a culture of Pseudomonas strain Ptm⁺ growing on hexachlorocyclohexane. Lipase activity was associated with growth of the bacterium and reached a peak at early idiophase (22 h). Following the lipase activity, bioemulsifier was produced, with maximum activity at mid-idiophase (32 h). The extracellular lipase is probably involved in the extracellular synthesis of the bioemulsifier in the culture broth.     

Reaction of selenomethionine with o-benzoquinone

A new reaction of selenomethionine with o-benzoquinone is described. This reaction can be used to distinguish between methionine and selenomethionine.     

Characterization of the pollen growth transition in self-incompatible <Emphasis Type="Italic">Petunia inflata</Emphasis>

In Petunia inflata, as in other species that shed bicellular pollen, early pollen tube growth in the pistil is slow, then increases 2- to 5-fold depending on the genotype of the female parent. We refer to the time point at which pollen tubes enter the accelerated phase of growth as the pollen growth transition (PGT). Here, we present evidence that pre-PGT and post-PGT growth are quantitatively and qualitatively different, and that the PGT is triggered when pollen tubes reach the transition zone (TZ) below the stigma. The capacity of various pistil zones to precipitate the PGT was tested through 'stump' pollinations: varying lengths of the pistil apex were excised, the cut surface of the remaining pistil (the stump) coated with stigmatic exudates then dusted with compatible pollen. Pollen applied to TZ tissues entered the PGT earlier than pollen growing in intact control pistils; the PGT was delayed in stylar stumps, largely because of delayed germination and reduced pre-PGT growth. In immature pistils, the PGT was delayed by several hours relative to its onset in mature pistils. The PGT fails to occur in pollen cultured in vitro. Collectively, the data suggest that pollen tubes become competent to enter the PGT when they reach a critical size, but the physicochemical environment of the transmitting tissue is necessary for triggering the cellular changes that result in accelerated growth. An analysis of the distribution of pollen tube tips before and after the PGT suggests that pollen competition is most intense during the pre-PGT phase.     

Combination treatment of elevated UVB radiation,CO2 and temperature has little effect on silver birch (Betula pendula) growth and phytochemistry

Elevations of carbon dioxide, temperature and ultraviolet‐B (UBV) radiation in the growth environment may have a high impact on the accumulation of carbon in plants, and the different factors may work in opposite directions or induce additive effects. To detect the changes in the growth and phytochemistry of silver birch (Betula pendula) seedlings, six genotypes were exposed to combinations of ambient or elevated levels of CO₂, temperature and UVB radiation in top‐closed chambers for 7 weeks. The genotypes were relatively similar in their responses, and no significant interactive effects of three‐level climate factors on the measured parameters were observed. Elevated UVB had no effect on growth, nor did it alter plant responses to CO₂ and/or temperature in combined treatments. Growth in all plant parts increased under elevated CO₂, and height and stem biomass increased under elevated temperature. Increased carbon distribution to biomass did not reduce its allocation to phytochemicals: condensed tannins, most flavonols and phenolic acids accumulated under elevated CO₂ and elevated UVB, but this effect disappeared under elevated temperature. Leaf nitrogen content decreased under elevated CO₂. We conclude that, as a result of high genetic variability in phytochemicals, B. pendula seedlings have potential to adapt to the tested environmental changes. The induction in protective flavonoids under UVB radiation together with the positive impact of elevated CO₂ and temperature mitigates possible UVB stress effects, and thus atmospheric CO₂ concentration and temperature are the climate change factors that will dictate the establishment and success of birch at higher altitudes in the future.     

The first report of autochthonous non-vector-borne transmission of canine leishmaniosis in the Nordic countries

Background

Leishmania spp. are zoonotic protozoans that infect humans and other mammals such as dogs. The most significant causative species in dogs is L. infantum. In dogs, leishmaniosis is a potentially progressive, chronic disease with varying clinical outcomes. Autochthonous cases of canine leishmaniosis have not previously been reported in the Nordic countries.

Results

In this report we describe the first diagnosed autochthonous cases of canine leishmaniosis in Finland, in which transmission via a suitable arthropod vector was absent. Two Finnish boxers that had never been in endemic areas of Leishmania spp., had never received blood transfusions, nor were infested by ectoparasites were diagnosed with leishmaniosis. Another dog was found with elevated Leishmania antibodies. A fourth boxer dog that had been in Spain was considered to be the source of these infections. Transmission occurred through biting wounds and semen, however, transplacental infection in one of the dogs could not be ruled out.Two of the infected dogs developed a serious disease and were euthanized and sent for necropsy. The first one suffered from membranoproliferative glomerulonephritis and the second one had a chronic systemic disease. Leishmania sp. was detected from tissues by PCR and/or IHC in both dogs. The third infected dog was serologically positive for Leishmania sp. but remained free of clinical signs.

Conclusions

This case report shows that imported Leishmania-infected dogs may pose a risk for domestic dogs, even without suitable local arthropod vectors.

     

Highly selective end-tagged antimicrobial peptides derived from PRELP

Background

Antimicrobial peptides (AMPs) are receiving increasing attention due to resistance development against conventional antibiotics. Pseudomonas aeruginosa and Staphylococcus aureus are two major pathogens involved in an array of infections such as ocular infections, cystic fibrosis, wound and post-surgery infections, and sepsis. The goal of the study was to design novel AMPs against these pathogens.

Methodology and Principal Findings

Antibacterial activity was determined by radial diffusion, viable count, and minimal inhibitory concentration assays, while toxicity was evaluated by hemolysis and effects on human epithelial cells. Liposome and fluorescence studies provided mechanistic information. Protease sensitivity was evaluated after subjection to human leukocyte elastase, staphylococcal aureolysin and V8 proteinase, as well as P. aeruginosa elastase. Highly active peptides were evaluated in ex vivo skin infection models. C-terminal end-tagging by W and F amino acid residues increased antimicrobial potency of the peptide sequences GRRPRPRPRP and RRPRPRPRP, derived from proline arginine-rich and leucine-rich repeat protein (PRELP). The optimized peptides were antimicrobial against a range of Gram-positive S. aureus and Gram-negative P. aeruginosa clinical isolates, also in the presence of human plasma and blood. Simultaneously, they showed low toxicity against mammalian cells. Particularly W-tagged peptides displayed stability against P. aeruginosa elastase, and S. aureus V8 proteinase and aureolysin, and the peptide RRPRPRPRPWWWW-NH₂ was effective against various “superbugs” including vancomycin-resistant enterococci, multi-drug resistant P. aeruginosa, and methicillin-resistant S. aureus, as well as demonstrated efficiency in an ex vivo skin wound model of S. aureus and P. aeruginosa infection.

Conclusions/Significance

Hydrophobic C-terminal end-tagging of the cationic sequence RRPRPRPRP generates highly selective AMPs with potent activity against multiresistant bacteria and efficiency in ex vivo wound infection models. A precise “tuning” of toxicity and proteolytic stability may be achieved by changing tag-length and adding W- or F-amino acid tags.     

Solid-supported 2'-O-glycoconjugation of oligonucleotides by azidation and click reactions

2'-O-[(2-Bromoethoxy)methyl]cytidine and 2'-O-[(2-azidoethoxy)methyl]cytidine have been prepared and introduced as appropriately protected 3'-phosphoramidite (1) and 3'-(H-phosphonate) (2) building blocks, respectively, into 2'-O-methyl oligoribonucleotides. The support-bound oligonucleotides were subjected to two consecutive conjugations with alkynyl-functionalized monosaccharides. The first saccharide was introduced by a Cu(I) promoted click reaction with 2 and the second by azidation of the 2-bromoethoxy group of 1 followed by the click reaction. The influence of the 2'-glycoconjugations on hybridization with DNA and 2'-O-methyl RNA targets was studied. Two saccharide units within a 15-mer oligonucleotide had a barely noticeable effect on the duplex stability, while introduction of a third one moderately decreased the melting temperature.     

Evaluation of Bioremediation Treatments in a Shoreline-Simulating Microcosm

A microcosm test was designed to study the efficiency of bioremediation treatments at oil contaminated shorelines. The biodegradation in the hermetically closed microcosm was monitored by measuring the total cumulative inorganic carbon evolved during the bioremediation process. The effects of three different additives, medium-release methylene urea (MU) + apatite, fast-release MU + superphosphate, and a biosorbent, on the biodegradation of weathered crude oil (North Sea Brent) were evaluated at +10°C. All the additives significantly increased mineralization. The total amount of inorganic carbon evolved during the 10-week study was measured in the microcosm treated with oil, and with oil and medium-release MU + apatite, fast-release MU + superphosphate, and biosorbent. The amounts were 40,670,490, and 580 mg, respectively. The respirometric measurements were supported by microbiological determinations, ATP content in the sand, number of heterotrophic bacteria, and amount of biomass-C determined by the substrate-induced respiration method. Nutrient analysis indicated that biodegradation was nitrogen limited. The microcosm test proved to be suitable for comparing the effectiveness of different treatments in enhancing the biodegradation of crude oil-contaminated shores.