Response of plant species richness and primary productivity in shrublands along a north–south gradient in Europe to seven years of experimental warming and drought: reductions in primary productivity in the heat and drought year of 2003

We used a nonintrusive field experiment carried out at six sites – Wales (UK), Denmark (DK), the Netherlands (NL), Hungary (HU), Sardinia (Italy – IT), and Catalonia (Spain – SP) – along a climatic and latitudinal gradient to examine the response of plant species richness and primary productivity to warming and drought in shrubland ecosystems. The warming treatment raised the plot daily temperature by ca. 1 °C, while the drought treatment led to a reduction in soil moisture at the peak of the growing season that ranged from 26% at the SP site to 82% in the NL site. During the 7 years the experiment lasted (1999–2005), we used the pin‐point method to measure the species composition of plant communities and plant biomass, litterfall, and shoot growth of the dominant plant species at each site. A significantly lower increase in the number of species pin‐pointed per transect was found in the drought plots at the SP site, where the plant community was still in a process of recovering from a forest fire in 1994. No changes in species richness were found at the other sites, which were at a more mature and stable state of succession and, thus less liable to recruitment of new species. The relationship between annual biomass accumulation and temperature of the growing season was positive at the coldest site and negative at the warmest site. The warming treatment tended to increase the aboveground net primary productivity (ANPP) at the northern sites. The relationship between annual biomass accumulation and soil moisture during the growing season was not significant at the wettest sites, but was positive at the driest sites. The drought treatment tended to reduce the ANPP in the NL, HU, IT, and SP sites. The responses to warming were very strongly related to the Gaussen aridity index (stronger responses the lower the aridity), whereas the responses to drought were not. Changes in the annual aboveground biomass accumulation, litterfall, and, thus, the ANPP, mirrored the interannual variation in climate conditions: the most outstanding change was a decrease in biomass accumulation and an increase in litterfall at most sites during the abnormally hot year of 2003. Species richness also tended to decrease in 2003 at all sites except the cold and wet UK site. Species‐specific responses to warming were found in shoot growth: at the SP site, Globularia alypum was not affected, while the other dominant species, Erica multiflora, grew 30% more; at the UK site, Calluna vulgaris tended to grow more in the warming plots, while Empetrum nigrum tended to grow less. Drought treatment decreased plant growth in several studied species, although there were some species such as Pinus halepensis at the SP site or C. vulgaris at the UK site that were not affected. The magnitude of responses to warming and drought thus depended greatly on the differences between sites, years, and species and these multiple plant responses may be expected to have consequences at ecosystem and community level. Decreases in biodiversity and the increase in E. multiflora growth at the SP site as a response to warming challenge the assumption that sensitivity to warming may be less well developed at more southerly latitudes; likewise, the fact that one of the studied shrublands presented negative ANPP as a response to the 2003 heat wave also challenges the hypothesis that future climate warming will lead to an enhancement of plant growth and carbon sequestration in temperate ecosystems. Extreme events may thus change the general trend of increased productivity in response to warming in the colder sites.     

Actinomycete Variants with Impaired Differentiation: Production in High Yield, Recognition and Phenotypic Characterization in Seven Species

S ummary . When plated on mineral synthetic media with D-fructose as a sole carbon and energy source 7 strains of actinomycetes belonging to different streptomycete species regularly produced secondary variant colonies in high yield. Beside the ability of strepto-mycetes to utilize fructose as a sole carbon source, the following factors were shown to be of importance in the control of variational events: the state of the parent culture used for platings; the composition of fructose-containing media used for the production of variants. Indole, anthranilate and phenol inhibited formation of secondary colonies by most strains. Phenotypically all the variants obtained shared in common the loss of ability to form secondary (aerial) mycelium and spores as well as a tendency of the substrate mycelium to fragment. These traits were shown to be: hereditarily stable on all media tested for variants derived from Streptcmyces ruber, Str. roseolus, Str. lateritius and Str. roseoflavus var. roseofungini; less stable and nutritionally affected for variants derived from Str. albocyaneus, Str. roseoflavus and Str. anthocyaneus; unstable on all except fructose-containing mineral medium for the variants of Str. flavofungini. Vegetative growth of some of the variants obtained was not inferior to that of parent cultures; some variants produced increased amounts of intracellular antibiotics. Some implications of the reported findings are discussed.     

Inhibition of Germination in Kochia indica

Seeds of Kochia indica Wight germinate rapidly in shallow water,but their germination is retarded on moist filter-paper. Theretardation is traced to a surface-active, saponin-like inhibitor,which is readily leached away in water and is adsorbed by charcoalor soil. Excised embryos may also remain dormant on filter-paper,but if rinsed in water quickly become active. Inhibition isfavoured by higher temperature (30°C. as against 20°or less), especially in an atmosphere of oxygen, although onceactive the embryos grow rapidly in such conditions. When theoxygen concentration is reduced to 5 per cent., germinationand growth are markedly retarded, but 5 per cent. CO₂ has littleor no retarding effect.     

Chemical characterization and anti-inflammatory effect of rauvolfian,a pectic polysaccharide of <Emphasis Type="Italic">Rauvolfia</Emphasis> callus

The pectic polysaccharide named rauvolfian RS was obtained from the dried callus of Rauvolfia serpentina L. by extraction with 0.7% aqueous ammonium oxalate. Crude rauvolfian RS was purified using membrane ultrafiltration to yield the purified rauvolfian RSP in addition to glucan as admixture from the callus, with molecular weights 300 and 100–300 kD, respectively. A peroral pretreatment of mice with the crude and purified samples of rauvolfian (RS and RSP) was found to decrease colonic macroscopic scores, the total area of damage, and tissue myelope roxidase activity in colons as compared with a colitis group. RS and RSP were shown to stimulate production of mucus by colons of the colitis mice. RSP appeared to be an active constituent of the parent RS. The glucan failed to possess anti-inflammatory activity. Published in Russian in Biokhimiya, 2007, Vol. 72, No. 7, pp. 955–962.     

Role of the Dinaric Karst (western Balkans) in shaping the phylogeographic structure of the threatened crayfish Austropotamobius torrentium

1. This study examines phylogeography and phylogeny of the threatened stone crayfish, Austropotamobius torrentium, in order to elucidate the role of the Dinaric Karst geology in shaping the evolutionary history and genetic diversity of aquatic fauna in the western Balkans. Mitochondrial 16S rRNA and COI genes were partially sequenced from 188 and 159 crayfish, respectively, sampled from 70 localities. Phylogenetic relationships were reconstructed using four methods of phylogenetic inference. Divergence times between phylogroups were estimated in a Bayesian framework, and their demographic history was examined using neutrality tests and mismatch distribution analysis. 2. Seven geographically localised phylogroups separated by pronounced genetic gaps were found. Five of them have a distribution range within the northern‐central Dinaric (NCD) region, while the remaining two include populations from the southern Balkans (SB) and central and south‐eastern Europe (CSE). The oldest divergence event separated two NCD lineages from the rest of populations in the Late Miocene or Early Pliocene. Divergences amongst the five NCD phylogroups and SB + CSE occurred in the Pliocene. The most recent split separated SB and CSE phylogroups during the Late Pliocene. For both genes, uncorrected pairwise divergences between most of the phylogroups (4.1–8.7% for COI and 1.6–4.8% for 16S rRNA) were of the same range as, or higher than, some of the interspecific distances previously reported for the genus Austropotamobius. 3. Geographically isolated and deeply divergent cryptic monophyletic phylogroups within A. torrentium in the NCD region arose in the course of intensification of Neotectonic movements during the Pliocene and the beginning of the Pleistocene and the development of karstification that has heavily fragmented the palaeohydrography of the area. The results confirm a gradual north–south expansion of stone crayfish during the pre‐Pleistocene that preceded the rapid northward post‐glacial re/colonisation of central Europe (CSE phylogroup) through the Danube drainage. 4. Austropotamobius torrentium comprises morphologically cryptic but molecularly distinct taxa. Considering the relatively small geographical areas they inhabit, the NCD phylogroups of stone crayfish should be given the highest conservation priority.     

Ontogenetic Pleiotropy of Genes Involved in CNVs in Human Spontaneous Abortions

Russian Journal of Genetics - Using chromosome microarray analysis, 52 samples of placental tissues from first trimester human spontaneous abortions were examined. One hundred twenty copy number...     

Biosynthesis of nanoparticles of metals and metalloids by basidiomycetes. Preparation of gold nanoparticles by using purified fungal phenol oxidases

The work shows the ability of cultured Basidiomycetes of different taxonomic groups—Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum, and Grifola frondosa—to recover gold, silver, selenium, and silicon, to elemental state with nanoparticles formation. It examines the effect of these metal and metalloid compounds on the parameters of growth and accumulation of biomass; the optimal cultivation conditions and concentrations of the studied ion-containing compounds for recovery of nanoparticles have been identified. Using the techniques of transmission electron microscopy, dynamic light scattering, X-ray fluorescence and X-ray phase analysis, the degrees of oxidation of the bioreduced elements, the ζ-potential of colloidal solutions uniformity, size, shape, and location of the nanoparticles in the culture fluid, as well as on the surface and the inside of filamentous hyphae have been determined. The study has found the part played by homogeneous chromatographically pure fungal phenol-oxidizing enzymes (laccases, tyrosinases, and Mn-peroxidases) in the recovery mechanism with formation of electrostatically stabilized colloidal solutions. A hypothetical mechanism of gold(III) reduction from HAuCl₄ to gold(0) by phenol oxidases with gold nanoparticles formation of different shapes and sizes has been introduced.

     

Dysbiotic manifestations during eradication therapy of Helicobacter pylori and their corrections

Forty-eight patients with duodenal peptic ulcer disease infected with Helicobacter pylori were examined. All patients undergo conventional 1-week eradication therapy. After its ending the patients were randomized to two groups: those who will be treated by synbiotics or control group. Normoflorin B and Normoflorin L, which contain bifidobacteria or lactobacilli in complex with different microelements, vitamins, aminoacids, organic acids, and antioxidants, were used as synbiotics. Morphologic study of biopsy samples of small intestine mucosa were performed in patients from both groups. It was determined that eradication therapy worsened existing symptoms of dyspepsia in 80.9% of cases or lead to their emergence, connected with dysbiotic manifestations, in 55.5% of patients. Inclusion of synbiotics in complex therapy resulted in rapid and effective elimination of dyspeptic symptoms, promoted recovery of affected morphologic and functional states of small intestine mucosal epithelium, and optimized metabolic processes important for the digestion.     

Activity of Lentinus edodes intracellular lectins at various developmental stages of the fungus

We studied changes of the hemagglutinating activity of intracellular lectins of the basidiomycete Lentinus edodes (shiitake) at various stages of its morphogenetic development depending on erythrocyte type, growth medium, and lectin purification degree. Under certain experimental conditions, the specific lectin activity at the brown mycelium film stage exceeded the corresponding value for nonpigmented mycelium. The sensitivity of the lectins towards trypsin-treated rabbit erythrocytes was no less than a hundredfold higher than towards any other erythrocyte type studied. The general regularities of specific activity change did not depend on nutrient medium composition. With purification of intracellular shiitake lectins, their sensitivity to human erythrocytes decreased seventyfold or more, whereas their sensitivity to rabbit erythrocytes increased by the same factor.