Thermotolerant and thermostable laccases

Laccases are phenol-oxidizing, usually four-copper containing metalloenzymes. For industrial and biotechnological purposes, laccases were among the first fungal oxidoreductases providing larger-scale applications such as removal of polyphenols in wine and beverages, conversion of toxic compounds and textile dyes in waste waters, and in bleaching and removal of lignin from wood and non-wood fibres. In order to facilitate novel and more efficient bio-catalytic process applications, there is a need for laccases with improved biochemical properties, such as thermostability and thermotolerance. This review gives a current overview on the sources and characteristics of such laccases, with particular emphasis on the fungal enzymes.     

16S rRNA targeted sandwich hybridization method for direct quantification of mycobacteria in soils

Boreal soils have been suspected reservoirs of infectious environmental mycobacteria. Detection of these bacteria in the environment is hampered by their slow growth. We applied a quantitative sandwich hybridization approach for direct detection of mycobacterial 16S rRNA in soil without a nucleic acid amplification step. The numbers of mycobacterial 16S rRNA molecules found in the soil indicated the presence of up to 10(7) to 10(8) mycobacterial cells per gram of soil. These numbers exceed by factor of 10 to 100 x the previous estimates of mycobacteria in soil based on culture methods. When real-time PCR with mycobacteria targeting primers was used to estimate the number of 16S rDNA copies in soil, one copy of 16S rDNA was detected per 10(4) copies of 16S rRNA. This is close to the number of 16S rRNA molecules detected per cell by the same method in laboratory pure cultures of M. chlorophenolicum. Therefore a major part of the mycobacterial DNA in the studied soils may thus have represented metabolically active cells. The 16S rRNA sandwich hybridization method described in this paper offers a culture independent solution for tracking environmental reservoirs of viable and potentially infectious mycobacteria.     

Differential regulation of manganese peroxidases and characterization of two variable MnP encoding genes in the white-rot fungus Physisporinus rivulosus

Manganese peroxidase (MnP) production in the white-rot basidiomycete Physisporinus rivulosus T241i was studied. Separate MnP isoforms were produced in carbon-limited liquid media supplemented with Mn²⁺, veratryl alcohol, or sawdust. The isoforms had different pH ranges for the oxidation of Mn²⁺ and 2,6-dimethoxyphenol. Although lignin degradation by white-rot fungi is often triggered by nitrogen depletion, MnPs of P. rivulosus were efficiently produced also in the presence of high-nutrient nitrogen, especially in cultures supplemented with veratryl alcohol. Two MnP encoding genes, mnpA and mnpB, were identified, and their corresponding cDNAs were characterized. Structurally, the genes showed marked dissimilarity, and the expression of the two genes implicated quantitative variation and differential regulation in response to manganese, veratryl alcohol, or sawdust. The variability in regulation and properties of the isoforms may widen the operating range for efficient lignin degradation by P. rivulosus.     

Regulation of lymphangiogenesis--from cell fate determination to vessel remodeling

Lymphatic vessels are important for the maintenance of normal tissue fluid balance, immune surveillance and adsorption of digested fats. During the past decade, the identification of lymphatic-specific markers and growth factors has enabled detailed studies of the lymphatic system, and gain- and loss-of-function experiments have greatly increased our understanding of the mechanisms of normal lymphatic development. Understanding the basic biology has provided novel insights into the pathologic conditions of the lymphatic system that contribute to lymphedema, inflammation or lymphatic metastasis, and opened possibilities for the development of better therapeutic strategies. Here we review the current knowledge about the molecular mechanisms regulating the development of the lymphatic vasculature; of the differentiation of lymphatic endothelial cells, of the regulation of the growth of lymphatic vessels, and of remodeling of the vasculature into a network consisting of lymphatic capillaries and collecting lymphatic vessels. Furthermore, we will discuss the molecular mechanisms involved in the pathological conditions of the lymphatic vessels.     

Development of antibodies against the putative proteinase maturation protein A in relation to pneumococcal carriage and otitis media

The putative pneumococcal proteinase maturation protein A is a potential pneumococcal vaccine candidate. We examined serum antipneumococcal proteinase maturation protein A antibodies at 6, 12, 18 and 24 months of age, and showed that the age-related development of antipneumococcal proteinase maturation protein A antibodies is associated with pneumococcal contacts. A higher antipneumococcal proteinase maturation protein A antibody concentration at 18 months of age tends to predict for a lower risk of pneumococcal acute otitis media in the following 6 months (relative risk: 0.84, 95% confidence interval: 0.62-1.13).     

Comparison of Variable-Number Tandem-Repeat Markers typing and IS1245 Restriction Fragment Length Polymorphism fingerprinting of Mycobacterium avium subsp. hominissuis from human and porcine origins

Background  

Animal mycobacterioses are regarded as a potential zoonotic risk and cause economical losses world wide. M. avium subsp. hominissuis is a slow-growing subspecies found in mycobacterial infected humans and pigs and therefore rapid and discriminatory typing methods are needed for epidemiological studies. The genetic similarity of M. avium subsp. hominissuis from human and porcine origins using two different typing methods have not been studied earlier. The objective of this study was to compare the IS1245 RFLP pattern and MIRU-VNTR typing to study the genetic relatedness of M. avium strains isolated from slaughter pigs and humans in Finland with regard to public health aspects.     

Retention of prolyl hydroxylase PHD2 in the cytoplasm prevents PHD2-induced anchorage-independent carcinoma cell growth

Cellular oxygen tension is sensed by a family of prolyl hydroxylases (PHD1-3) that regulate the degradation of hypoxia-inducible factors (HIF-1α and -2α). The PHD2 isoform is considered as the main downregulator of HIF in normoxia. Our previous results have shown that nuclear translocation of PHD2 associates with poorly differentiated tumor phenotype implying that nuclear PHD2 expression is advantageous for tumor growth. Here we show that a pool of PHD2 is shuttled between the nucleus and the cytoplasm. In line with this, accumulation of wild type PHD2 in the nucleus was detected in human colon adenocarcinomas and in cultured carcinoma cells. The PHD2 isoforms showing high nuclear expression increased anchorage-independent carcinoma cell growth. However, retention of PHD2 in the cytoplasm inhibited the anchorage-independent cell growth. A region that inhibits the nuclear localization of PHD2 was identified and the deletion of the region promoted anchorage-independent growth of carcinoma cells. Finally, the cytoplasmic PHD2, as compared with the nuclear PHD2, less efficiently downregulated HIF expression. Forced HIF-1α or -2α expression decreased and attenuation of HIF expression increased the anchorage-independent cell growth. However, hydroxylase-inactivating mutations in PHD2 had no effect on cell growth. The data imply that nuclear PHD2 localization promotes malignant cancer phenotype.     

Effects of habitat restoration on peatland bird communities

Restoration of damaged ecosystems has become an important tool to slow down biodiversity loss and to maintain ecosystem services. Peatland bird populations have shown a substantial decline during the recent decades in Northern Europe as a consequence of peatland drainage. We studied whether restoration of peatlands drained for forestry affects bird communities. We conducted bird surveys at 11 peatlands in Western Finland, where each of the restored and their pristine counterparts were surveyed before restoration and yearly after restoration during 2010–2018. We used linear mixed effect models to analyze whether restoration affected the number of species and territories of peatland specialist and non‐specialist species and permutational multivariate analysis of variance to analyze the change in community composition. Drained parts of the peatlands had higher number of territories of non‐specialist species before restoration, and restoration seemed to decrease these numbers towards the level of pristine parts. By contrast, restoration did not affect the number of peatland specialists and their territories, which was lower in drained than in pristine parts of the peatlands. Bird communities in restored parts remained different from pristine parts in terms of community composition after restoration. Thus, despite the effect of restoration on non‐specialists, a substantially long time may be required for a recovery of the peatland bird communities. Based on our results, it seems that long‐term monitoring of the restored and pristine peatlands is needed to determine whether restoration is effective in recovering the peatland specialist bird species and bird communities in general.     

Cytoplasmic oxysterol-binding proteins: sterol sensors or transporters?

Families of oxysterol-binding protein (ORP) homologues are present in eukaryotes from yeast to man. Their hallmark feature is a characteristic ligand binding domain that, for several family members, has been shown to accommodate different oxysterols and/or cholesterol. ORPs of the “long” subtype contain targeting determinants for the endoplasmic reticulum and to other organelle membranes, the most prominent of which are phosphoinositide-binding pleckstrin homology domains, while “short” ORPs comprise a ligand binding domain with little additional sequences. There is increasing evidence that both long and short ORPs can be enriched at membrane contact sites, junctions of the endoplasmic reticulum with other organelles, where they are suggested to execute regulatory or sterol transfer functions. In this review we discuss the current evidence for putative roles of ORPs as sterol sensors or transporters.     

The effects of <Emphasis Type="Italic">N</Emphasis>-acyl chain methylations on ceramide molecular properties in bilayer membranes

Long-chain saturated ceramides possess the ability to form gel domains in fluid bilayer membranes. Such domains may also contain sphingomyelin, but generally exclude cholesterol. We studied the effect of N-acyl chain methylations on the ability of ceramide to form ceramide- and sphingomyelin-containing gel domains that displace sterol. Fluorescence quenching of probes displaying different lateral partitioning in heterogeneous lipid bilayers showed that the methyl branches induced position-dependent changes in the lateral distribution of the ceramides. Distally monomethylated ceramides interacted with sphingomyelin and displaced sterol, whereas proximally monomethylated and polymethylated ceramides appeared to be located outside of sterol/sphingomyelin-enriched domains. The branched ceramides also markedly reduced the bilayer affinity for sterol as determined from the equilibrium partitioning of sterol between lipid vesicles and cyclodextrin. Altogether, alterations in intermolecular interactions induced by the methyl branches markedly affected the molecular properties of ceramide in artificial bilayers.