Functional divergence of former alleles in an ancient asexual invertebrate

Theory suggests it should be difficult for asexual organisms to adapt to a changing environment because genetic diversity can only arise from mutations accumulating within direct antecedents and not through sexual exchange. In an asexual microinvertebrate, the bdelloid rotifer, we have observed a mechanism by which such organisms could acquire the diversity needed for adaptation. Gene copies most likely representing former alleles have diverged in function so that the proteins they encode play complementary roles in survival of dry conditions. One protein prevents desiccation-sensitive enzymes from aggregating during drying, whereas its counterpart does not have this activity, but is able to associate with phospholipid bilayers and is potentially involved in maintenance of membrane integrity. The functional divergence of former alleles observed here suggests that adoption of asexual reproduction could itself be an evolutionary mechanism for the generation of diversity.     

High-probability uniquantal transmission at excitatory synapses in barrel cortex

The number of vesicles released at excitatory synapses and the number of release sites per synaptic connection are key determinants of information processing in the cortex, yet they remain uncertain. Here we show that the number of functional release sites and the number of anatomically identified synaptic contacts are equal at connections between spiny stellate and pyramidal cells in rat barrel cortex. Moreover, our results indicate that the amount of transmitter released per synaptic contact is independent of release probability and the intrinsic release probability is high. These properties suggest that connections between layer 4 and layer 2/3 are tuned for reliable transmission of spatially distributed, timing-based signals.     

Levantilides A and B, 20-membered macrolides from a Micromonospora strain isolated from the Mediterranean deep sea sediment

Two new 20-membered macrolides, levantilide A and B, were isolated from the Micromonospora strain M71-A77. Strain M71-A77 was recovered from an Eastern Mediterranean deep-sea sediment sample and revealed to produce the levantilides under in situ salinity of 38.6 ‰. The chemical structures of the levantilides were elucidated on the basis of different one- and two- dimensional NMR experiments. Levantilide A exhibits a moderate antiproliferative activity against several tumor cell lines.     

Phosphorus pools in soil after land conversion from silvopasture to arable and grassland use

Differences in soil P among silvopasture, grassland, and arable lands have been well established. Nevertheless, most of the reports compare soil properties under long‐term sites. Thus, there exists little information on the effect of the conversion of silvopasture to arable or grassland use on soil P pools. The objective of the study was to determine the impact of converting silvopasture system (SP) into arable cropping and grassland system on the distribution of P pools and potential P bioavailability. We compared the following systems: SP system, SP converted to arable cropland (SP‐AL), SP converted to grassland (SP‐GL), and for comparative purposes, a long‐term arable cropland (AL). The P fractionation was performed by a sequential extraction scheme, using acid and alkaline extractants on samples collected from the 0–10 and 10–20 cm soil layers. It was assumed that the large variations in soil‐P fractionations are caused by the different management practices associated with land conversion. The results of P fractionation showed a dominance of calcium‐bound P, HCl‐extractable Pi constituted up to 36% of the soil total P (TP). However, the type of land use did not affect this P fraction. On the other hand, the reduction in labile‐P_i and NaOH‐P_i fractions observed at the SP‐AL site may have led to the decline in readily available P. The soil total organic P (TP_o) content was 8% and 17% lower at SP‐AL compared to SP and SP‐GL site, respectively. Labile organic‐P (labile‐P_o) content was markedly higher at SP site compared to arable soils, and was ≈ 10% of TP_o. The NaOH‐P_o constituted the highest fraction of the organic‐P pool (55%–79% of TP_o) across all the study systems, and was positively correlated with TP_o (p < 0.01). The study indicates that conversion of SP system in temperate regions to arable cropping with conventional tillage seems to result in the reduction of P availability compared to SP, indicating SP as an important land‐use practice.     

Designing protected areas to conserve riverine biodiversity: Lessons from a hypothetical redesign of the Kruger National Park

The process of designing protected areas to represent all ecosystems in an area adequately is becoming increasingly sophisticated. To date freshwater aquatic ecosystems have seldom been considered in this process. How much of a difference does it make when they are considered as well?This study examined the conservation of riverine biodiversity within 17 assessment units contained by the catchment areas of five perennial rivers flowing through Kruger National Park and two seasonal rivers that are largely contained within this park. Physical river types, fish species and invertebrate families or genera were used as surrogates of riverine biodiversity. Conservation planning software was used to select an optimal set of planning units to represent and maintain riverine biodiversity.The current spatial configuration of Kruger National Park, largely an accident of history, is particularly poor when assessed against the objective of conserving riverine biodiversity. Several alternative layouts are examined. These options are theoretical since there is little current opportunity to reassign land uses in the region. This study shows that substantially improved layouts for both riverine and terrestrial biodiversity are possible, under the constraint of the same total area under protection. The study also shows that even these optimal layouts are only partially successful in efforts to conserve fully representative samples of riverine biodiversity. Because of the longitudinal connectivity of rivers, conservation strategies that extend beyond protected areas are essential. Explicit conservation visions, targets and strategies need to be included in integrated water resource management plans.Based on the results of this study, nine recommendations are provided for increasing the effectiveness of current and future protected areas in conserving riverine biodiversity. These are to use systematic conservation planning to make biodiversity benefits explicit; mend the disconnect between terrestrial and freshwater conservation; use multiple surrogates wherever possible; be strategic about the collection and management of primary data; strive for maximum hydrologic connectivity; resist development pressure; foster good relationships across park fences; where relevant, pursue multi-national cooperation at the basin scale; and engage the value debate and resolve awareness and capacity constraints.     

Chemical composition of vintage preban absinthe with special reference to thujone, fenchone, pinocamphone, methanol, copper, and antimony concentrations

Thirteen samples of authentic absinthe dating from the preban era (i.e., prior to 1915) were analyzed for parameters that were hypothesized as contributing to the toxicity of the spirit, including naturally occurring herbal essences (thujone, pinocamphone, fenchone), methanol, higher alcohols, copper, and antimony. The total thujone content of preban absinthe was found to range between 0.5 and 48.3 mg/L, with an average concentration of 25.4 +/- 20.3 mg/L and a median concentration of 33.3 mg/L. The authors conclude that the thujone concentration of preban absinthe was generally overestimated in the past. The analysis of postban (1915-1988) and modern commercial absinthes (2003-2006) showed that the encompassed thujone ranges of all absinthes are quite similar, disproving the supposition that a fundamental difference exists between preban and modern absinthes manufactured according to historical recipes. Analyses of pinocamphone, fenchone, base spirits, copper, and antimony were inconspicuous. All things considered, nothing besides ethanol was found in the absinthes that was able to explain the syndrome "absinthism".     

Microarray-based detection and typing of foot-and-mouth disease virus

Foot-and-mouth disease virus (FMDV) is the most economically important veterinary pathogen because of its highly infectious nature and the devastating effects the virus has on the livestock industry. Rapid diagnostic methods are needed for detection and typing of FMDV serotypes and differentiation from other viruses causing vesicular diseases. We developed a microarray-based test that uses a FMD DNA chip containing 155 oligonucleotide probes, 35-45 base pair (bp) long, virus-common and serotype-specific, designed from the VP3-VP1-2A region of the genome. A set of two forward primers and one reverse primer were also designed to allow amplification of approximately 1100 bp of target sequences from this region. The amplified target was labelled with Alexa-Fluor 546 dye and applied to the FMD DNA chip. A total of 23 different FMDV strains representing all seven serotypes were detected and typed by the FMD DNA chip. Microarray technology offers a unique capability to identify multiple pathogens in a single chip.     

Segregation of bunch orientation in plantain and banana hybrids

Bunch orientation is an economically important trait in plantain (Musa spp. AAB group) and banana (Musa spp. AAA or ABB groups). Pendulous bunches are more symmetrical than subhorizontal, horizontal, or erect bunches and are, therefore, better adapted for transportation. Erect, horizontal, subhorizontal, and pendulous bunches were observed in segregating populations derived from crosses between plantains and bananas and among bananas. A proposed genetic model controlling this trait was tested in four populations. The true breeding diploid banana line, 'Calcutta 4' shows a pendulous bunch and has recessive alleles at three bunch orientation loci. The diploid banana cultivar 'Pisang lilin', which is heterozygous for the three loci, has a subhorizontal bunch. The triploid AAB plantain cultivar 'Bobby Tannap' has two simplex and one duplex loci, which also results in subhorizontal bunch orientation. The other plantain cultivar, 'Obino l'Ewai', which is simplex for two loci and nulliplex for the third, has a pendulous bunch due to dosage effects at the triploid level of the recessive alleles at simplex loci. Two tetraploid hybrids (TMPx 582-4 and 1187-8) have a subhorizontal bunch because of its duplex genotype for two loci and simplex genotype for the other locus. Bunch orientation might be an oligogenic trait regulated by the epistatic effects of at least three dominant loci. This revised version was published online in July 2006 with corrections to the Cover Date.     

Einfluss von Blattdüngung und Lagerverfahren auf die Druckstellenempfindlichkeit von Äpfeln

The influence of foliar fertilization and storage method on the bruise sensitivity of apples was investigated. The foliar fertilization was carried out with calcium, manganese or zinc by the cultivars ‘Braeburn’ and ‘Jonagold’. Fruits have been stored at 2°C in normal atmosphere (cold storage) or in film bags (CA-/ULO-storage (CA?=?controlled atmosphere, ULO?=?ultra low oxygen) for three months. Monthly fruits were bruised with a penetrometer applying a range of pressures. One day later the appearance of bruises was evaluated. Increasing pressures resulted in bruises of increasing severity. Foliar fertilization had no effect on the bruise susceptibility of both cultivars. The application of manganese and zinc led to an increase of manganese and zinc concentration in the leaves. The calcium concentration of fruits was not affected by the manganese and zinc application. The application of calcium increased the calcium concentration in the leaves and fruits to a lower degree, but no effect on the bruise sensitivity could be observed. No differences were observed in storage conditions, but duration of storage increased the bruise sensitivity of ‘Braeburn’. In comparison of the cultivars ‘Braeburn’ was less sensitive than ‘Jonagold’.     

Phosphorus speciation in sediments from the Baltic Sea,evaluated by a multi-method approach

Journal of Soils and Sediments - Phosphorus (P) is a crucial element for living organisms at both land and sea, but simultaneously, it can cause environmental problems especially in marine...