Direct Compression of Cellulose and Lignin Isolated by a New Catalytic Treatment

Tablet compression of softwood cellulose and lignin prepared by a new catalytic oxidation and acid precipitation method were investigated and compared with the established pharmaceutical direct compression excipients. Catalytic pretreated softwood cellulose (CPSC) and lignin (CPSL) were isolated from pine wood (Pinus sylvestris). The compaction studies were carried out with an instrumented eccentric tablet machine. The plasticity and elasticity of the materials under compression were evaluated using force-displacement treatment and by determining characteristic plasticity (PF) and elasticity (EF) factors. With all biomaterials studied, the PF under compression decreased exponentially as the compression force increased. The compression force applied in tablet compression did not significantly affect the elasticity of CPSC and microcrystalline cellulose (MCC) while the EF values for softwood lignins increased as compression force increased. CPSL was clearly a less plastically deforming and less compactable material than the two celluloses (CPSC and MCC) and hardwood lignin. CPSL presented deformation and compaction behaviour almost identical to that of lactose monohydrate. In conclusion, the direct tablet compression behaviour of native lignins and celluloses can greatly differ from each other depending on the source and isolation method used.     

Upper Ordovician sequences of western Estonia

The Upper Ordovician (uppermost Caradoc-Ashgill) section of western Estonia consists of a series of seven open-shelf carbonate sequences. Depositional facies grade laterally through a series of shelf-to-basin facies belts: grain-supported facies (shallow shelf), mixed facies (middle shelf), mud-supported facies (deep shelf and slope) and black shale facies (basin). Locally, a stromatactis mud mound occurs in a middle-to-deep shelf position. Shallow-to-deep shelf facies occur widely across the Estonian Shelf and grade laterally through a transitional (slope) belt into the basinal deposits of the Livonian Basin.

Each sequence consists of a shallowing-upward, prograding facies succession. Sequences 1 (Upper Nabala Stage) and 2 (Vormsi Stage) record step-wise drowning of underlying shelf units (lower Nabala) that culminated in the deposition of the most basinal facies (Fjäcka Shale) in the Livonian Basin. Sequences 3–6 comprise the overlying Pirgu Stage and record the gradual expansion of shallow and middle-shelf facies across the Estonian Shelf. The Porkuni Stage (sequence 7) is bracketed by erosional surfaces and contains the shallowest-water facies of the preserved strata. The uppermost part of the section (Normalograptus persculptus biozone) is restricted to the Livonian Basin, and includes redeposited carbonate and siliciclastic grains; it is the lowstand systems tract of the lowest Silurian sequence 8. Sequence 7 and the overlying basinal redeposited material (i.e., the lowstand of sequence 8) correspond to the latest Ordovician (Hirnantian) glacial interval, and the bracketing unconformities are interpreted as the widely recognized early and late Hirnantian glacial maximums.

The sequences appear correlative to Upper Ordovician sequences in Laurentia. Graptolite biozones indicated that the Estonian sequences are equivalent to carbonate ramp sequences in the western United States (Great Basin) and mixed carbonate-siliciclastic sequences in the eastern United States (Appalachian Basin–Cincinnati Arch region). These correlations indicate a strong eustatic control over sequence development despite the contrasting tectonic settings of these basins.     

Using quantitative pollen-based land-cover estimations and a spatial CA_Markov model to reconstruct the development of cultural landscape at Rõuge,South Estonia

Quantitative pollen-based land-cover reconstruction covering the last 4,000 years was performed using transformation coefficients derived from a modern pollen land-cover database and a palynological record from an annually laminated sequence in Lake Rõuge Tõugjärv. Proportions of four land-cover classes characteristic of cultural landscape were reconstructed: habitation area, arable land, grassland and woodland. A land-use change model using CA_Markov analysis was applied for spatial reconstructions for seven periods: 600 b.c., a.d. 300, 800, 1200, 1700, 1870 and 1940. Historical maps from a.d. 1684, 1870–1899 and 1935 were used for calibration of quantitative estimates and to validate spatial reconstructions. The accuracy of the estimates depends on the availability of modern analogues and differs among land-cover classes, being highest for classes with directly connectable pollen indicator types (arable land, forest) and lowest for settlement areas. Spatial reconstructions produced by the CA_Markov land-cover change model show moderate accordance with historical data. However, the large uncertainties in land-cover input data must be considered in the evaluation of the KIA results of the spatial model. Permanent low intensity, rural land-use in the Rõuge area started at the beginning of the Bronze Age (c. 1800 b.c.). The major increase in the extent of rural land-use took place at the beginning of the 13th century and culminated during the 19th century when c. 90% of the RSAP of Rõuge Tõugjärv was open. During the last century, rural land-use decreased constantly.     

Mitogenetic structure of brown bears (Ursus arctos L.) in northeastern Europe and a new time frame for the formation of European brown bear lineages

We estimated the phylogenetic relationships of brown bear maternal haplotypes from countries of northeastern Europe (Estonia, Finland and European Russia), using sequences of mitochondrial DNA (mtDNA) control region of 231 bears. Twenty-five mtDNA haplotypes were identified. The brown bear population in northeastern Europe can be divided into three haplogroups: one with bears from all three countries, one with bears from Finland and Russia, and the third composed almost exclusively of bears from European Russia. Four haplotypes from Finland and European Russia matched exactly with haplotypes from Slovakia, suggesting the significance of the current territory of Slovakia in ancient demographic processes of brown bears. Based on the results of this study and those from the recent literature, we hypothesize that the West Carpathian Mountains have served either as one of the northernmost refuge areas or as an important movement corridor for brown bears of the Eastern lineage towards northern Europe during or after the last ice age. Bayesian analyses were performed to investigate the temporal framework of brown bear lineages in Europe. The molecular clock was calibrated using Beringian brown bear sequences derived from radiocarbon-dated ancient samples, and the estimated mutation rate was 29.8% (13.3%-47.6%) per million years. The whole European population and Western and Eastern lineages formed about 175,000, 70,000 and 25,000 years before present, respectively. Our approach to estimating the time frame of brown bear evolution demonstrates the importance of using an appropriate mutation rate, and this has implications for other studies of Pleistocene populations.     

A European Concern? Genetic Structure and Expansion of Golden Jackals (Canis aureus) in Europe and the Caucasus

In the first continent-wide study of the golden jackal (Canis aureus), we characterised its population genetic structure and attempted to identify the origin of European populations. This provided a unique insight into genetic characteristics of a native carnivore population with rapid large-scale expansion. We analysed 15 microsatellite markers and a 406 base-pair fragment of the mitochondrial control region. Bayesian-based and principal components methods were applied to evaluate whether the geographical grouping of samples corresponded with genetic groups. Our analysis revealed low levels of genetic diversity, reflecting the unique history of the golden jackal among Europe’s native carnivores. The results suggest ongoing gene flow between south-eastern Europe and the Caucasus, with both contributing to the Baltic population, which appeared only recently. The population from the Peloponnese Peninsula in southern Greece forms a common genetic cluster with samples from south-eastern Europe (ΔK approach in STRUCTURE, Principal Components Analysis [PCA]), although the results based on BAPS and the estimated likelihood in STRUCTURE indicate that Peloponnesian jackals may represent a distinct population. Moreover, analyses of population structure also suggest either genetic distinctiveness of the island population from Samos near the coast of Asia Minor (BAPS, most STRUCTURE, PCA), or possibly its connection with the Caucasus population (one analysis in STRUCTURE). We speculate from our results that ancient Mediterranean jackal populations have persisted to the present day, and have merged with jackals colonising from Asia. These data also suggest that new populations of the golden jackal may be founded by long-distance dispersal, and thus should not be treated as an invasive alien species, i.e. an organism that is “non-native to an ecosystem, and which may cause economic or environmental harm or adversely affect human health”. These insights into the genetic structure and ancestry of Baltic jackals have important implications for management and conservation of jackals in Europe. The golden jackal is listed as an Annex V species in the EU Habitats Directive and as such, considering also the results presented here, should be legally protected in all EU member states.     

Tree taxa immigration to the eastern Baltic region,southeastern sector of Scandinavian glaciation during the Late-glacial period (14,500–11,700 cal. b.p.)

The eastern Baltic region is situated in the southeastern part of the area which was covered by the last Scandinavian glaciation. Four well-dated sediment profiles from sites distributed along a ~330-km north–south transect were analysed for their macrofossil contents. The immigration of tree taxa during the Late-glacial (LG) period, which was the time of environmental change from tundra to woodland in previously glaciated areas, can be determined from these data. The pioneer vegetation in the study area was treeless dwarf shrub tundra with various dominant taxa. The so-called Allerød hemispheric warming permitted the Post-glacial immigration of trees into the southern part of the eastern Baltic region; however, these most probably disappeared during the following cold period, the Younger Dryas/GS-1. The local presence of Betula sect. Albae, Pinus sylvestris, Populus tremula and Picea abies during the LG period in the southern part of the region was confirmed. The northern part of the area presumably remained treeless for the entire LG period. Therefore, until the beginning of the Holocene, the tree line in the eastern Baltic region did not reach beyond 58°N.     

Nano-coating of β-galactosidase onto the Surface of Lactose by Using an Ultrasound-assisted Technique

We nano-coated powdered lactose particles with the enzyme β-galactosidase using an ultrasound-assisted technique. Atomization of the enzyme solution did not change its activity. The amount of surface-attached β-galactosidase was measured through its enzymatic reaction product D-galactose using a standardized method. A near-linear increase was obtained in the thickness of the enzyme coat as the treatment proceeded. Interestingly, lactose, which is a substrate for β-galactosidase, did not undergo enzymatic degradation during processing and remained unchanged for at least 1 month. Stability of protein-coated lactose was due to the absence of water within the powder, as it was dry after the treatment procedure. In conclusion, we were able to attach the polypeptide to the core particles and determine precisely the coating efficiency of the surface-treated powder using a simple approach.     

Organization and assembly of metal-thiolate clusters in epithelium-specific metallothionein-4

Mammalian metallothionein-4 (MT-4) was found to be specifically expressed in stratified squamous epithelia where it plays an essential but poorly defined role in regulating zinc or copper metabolism. Here we report on the organization, stability, and the pathway of metal-thiolate cluster assembly in MT-4 reconstituted with Cd(2+) and Co(2+) ions. Both the (113)Cd NMR studies of (113)Cd(7)MT-4 and the spectroscopic characterization of Co(7)MT-4 showed that, similar to the classical MT-1 and MT-2 proteins, metal ions are organized in two independent Cd(4)Cys(11) and Cd(3)Cys(9) clusters with each metal ion tetrahedrally coordinated by terminal and bridging cysteine ligands. Moreover, we have demonstrated that the cluster formation in Cd(7)MT-4 is cooperative and sequential, with the Cd(4)Cys(11) cluster being formed first, and that a distinct single-metal nucleation intermediate Cd(1)MT-4 is required in the cluster formation process. Conversely, the absorption and circular dichroism features of metal-thiolate clusters in Cd(7)MT-4 indicate that marked differences in the cluster geometry exist when compared with those in Cd(7)MT-1/2. The biological implication of our studies as to the role of MT-4 in zinc metabolism of stratified epithelia is discussed.     

Binding of zinc(II) and copper(II) to the full-length Alzheimer's amyloid-beta peptide

There is evidence that binding of metal ions like Zn2+ and Cu2+ to amyloid beta-peptides (Abeta) may contribute to the pathogenesis of Alzheimer's disease. Cu2+ and Zn2+ form complexes with Abeta peptides in vitro; however, the published metal-binding affinities of Abeta vary in an enormously large range. We studied the interactions of Cu2+ and Zn2+ with monomeric Abeta(40) under different conditions using intrinsic Abeta fluorescence and metal-selective fluorescent dyes. We showed that Cu(2+) forms a stable and soluble 1 : 1 complex with Abeta(40), however, buffer compounds act as competitive copper-binding ligands and affect the apparent K(D). Buffer-independent conditional K(D) for Cu(II)-Abeta(40) complex at pH 7.4 is equal to 0.035 micromol/L. Interaction of Abeta(40) with Zn2+ is more complicated as partial aggregation of the peptide occurs during zinc titration experiment and in the same time period (within 30 min) the initial Zn-Abeta(40) complex (K(D) = 60 micromol/L) undergoes a transition to a more tight complex with K(D) approximately 2 micromol/L. Competition of Abeta(40) with ion-selective fluorescent dyes Phen Green and Zincon showed that the K(D) values determined from intrinsic fluorescence of Abeta correspond to the binding of the first Cu2+ and Zn2+ ions to the peptide with the highest affinity. Interaction of both Zn2+ and Cu2+ ions with Abeta peptides may occur in brain areas affected by Alzheimer's disease and Zn2+-induced transition in the peptide structure might contribute to amyloid plaque formation.