Effects of a hydropower plant on Coleopteran diversity and abundance in the Udzungwa Mountains, Tanzania

The effects of river flow diversion on biodiversity were assessed using Coleoptera as an indicator group in three habitats of the Kihansi Gorge (Udzungwa Mountains, Tanzania), before and after commissioning of a hydropower plant. Data collected using sweep netting and pitfall traps showed that the effect of diversion of the river flow was site-specific, affecting particularly the spray habitat. Rarefaction analysis of both sweep netting and pitfall samples indicated that the expected richness of Coleoptera declined significantly in all habitats after commissioning of the power plant. Sweep netting and pitfall samples showed that the highest Shannon–Wiener diversity index value before the diversion of the river flow was in the spray zone, but the index value decreased after diversion. Changes in the other two habitats were less prominent. Analysis of variance using diversity index values from five pitfall samples in each habitat type before and after commissioning indicated that there were no statistically significant differences in the diversity index between the two sampling periods or among the three habitat types. Renkonen's similarity index between habitats showed that pitfall samples had higher similarity (87%) than did samples from sweep netting (69%). It is suggested that for mitigation purposes, artificial spray systems, which have been installed in other wetlands of the Kihansi Gorge, also be installed to cover the whole Lower Wetland in which this study was undertaken. In order to maintain overall biodiversity in the Kihansi Gorge, it is suggested that the ecosystem conservation approach be prioritised.     

Variable responses of waterfowl breeding populations to long-term removal of introduced American mink

It is suspected that feral American mink, an introduced predator in Europe, have seriously affected local densities of birds breeding in archipelagos and coastal areas. We studied the effects of mink removal on breeding densities of waterfowl in two manipulation and two control areas in the outer archipelago of SW Finland, Baltic Sea. The study was conducted in two phases: during 1992–2001 a total of 98 mink was removed from 60 islands and islets (total area 72 km²) whereas on 37 islands and islets (35 km²) mink was not removed. Additional mink removal and control areas were established during 1998–2001 to replicate the experiment. The breeding densities of the shelduck, tufted duck and the velvet scoter increased as a response to mink removal, while in the control areas their populations remained unchanged. The breeding densities of mallards increased during the first 7 yr of mink removal, but a steep decrease in the last study year resulted in a statistically non-significant overall increase. The species with low breeding densities (the gadwall, northern shoveler, pintail and the red-breasted merganser) increased as well. In contrast, the populations of large waterfowl species, the mute swan, greylag goose, common eider and the goosander, did not show obvious increases in breeding densities after mink removal. We conclude that feral mink may locally limit the breeding densities of some smaller waterfowl species and thus reduce the diversity of the waterfowl community in the outer archipelago.     

Hcn and Hnc in Comets C/2000 Wm1 (Linear) and C/2002 C1 (Ikeya-Zhang)

Comets have been suggested as a possibly significant source of organic molecules to the early Earth. Hydrogen cyanide (HCN) is important in models of prebiotic chemistry, but may be difficult to form in the early terrestrial environment, while hydrogen isocyanide (HNC) is a `classical' tracer of interstellar ion-molecule chemistry. We have observed both HCN and HNC in 2 recent comets, bringing the number of comets with published measurements of the HNC/HCN abundance ratio to 6. The HNC/HCN ratio in comet Ikeya-Zhang appears to increase with decreasing heliocentric distance, as was previously observed for comet Hale-Bopp, indicating that the HNC is produced at least in part by processes in the cometary coma (atmosphere) and is not simply a constituent of the nuclear ices. Both comets C/2000 WM1 (Linear) and C/2002 C1 (Ikeya-Zhang) exhibit values of the HNC/HCN ratio that appear to be too large (0.09–0.19) tobe matched by current models of coma chemistry. Cometary HNC maybe a photodissociation product of organic grains or large organic polymers stored in the nucleus. We have also set a limit on the emission from the NO radical in comet WM1.     

Interstellar Ices as a Source of CN-Bearing Molecules in Protoplanetary Disks

A reliable model for the composition and evolution of interstellar ices inregions of active star formation is fundamental to our quest to determinethe organic inventory of planetesimals in the early Solar System. This hasbecome a realistic goal since the launch of the Infrared Space Observatory,which provides a facility for infrared spectroscopy unhindered by telluricabsorption over the entire spectral range of vibrational modes in solids ofexobiological interest. Interstellar molecules detected in the solid phaseto date include H_{_2O}, NH₃, CO, CO₂,CH₃OH, CH₄, H₂CO, OCS andHCOOH, together with a CN-bonded absorber generically termed`XCN'. In this article, we focus on cosmic synthesis of CN-bearing species,as this important class of prebiotic molecules may not have formedendogenously in significant quantities on early Earth if conditions were nothighly reducing. Experiments in which interstellar ice analogs are subjectto UV photolysis or energetic ion bombardment yield CN-rich residues with aspectral signature that matches a corresponding feature observed in youngprotostars enshrouded in dust and gas. CN-bearing species are also presentin cometary ices, with a combined abundance comparable to the lower end of therange observed in protostars. Energetic processing of interstellar ices isthus a viable and potentially significant source of CN compounds inprotoplanetary disks.     

Generic method for modular surface modification of cellulosic materials in aqueous medium by sequential "click" reaction and adsorption

A generic approach for heterogeneous surface modification of cellulosic materials in aqueous medium, applicable for a wide range of functionalizations, is presented. In the first step, carboxymethyl cellulose (CMC) modified with azide or alkyne functionality, was adsorbed on a cellulosic substrate, thus, providing reactive sites for azide-alkyne cycloaddition click reactions. In the second step, functional units with complementary click units were reacted on the cellulose surface, coated by the click-modified CMC. Selected model functionalizations on diverse cellulosic substrates are shown to demonstrate the generality of the approach. The concept by sequentially combining the robust physical adsorption ("physical click") and robust chemical reaction ("chemical click") allows versatile, simple, and environmentally friendly modification of a cellulosic substrate with virtually any azide- or alkyne-modified molecule and even functionalization with several types of units.     

Log-normal distribution of species abundances is not a universal indicator of rain forest disturbance

1. The fit to log-normal distribution of species abundances of grasshoppers, ladybird beetles, tortoise beetles and dung beetles and forest floor vegetation in unlogged and selectively felled sites in Kibale Forest, western Uganda was analysed. It was shown that the fit to log-normal distribution cannot be used as a straightforward universal indicator of rainforest disturbance.     

Coleopteran diversity and abundance in different habitats near Kihansi waterfall, in the Udzungwa Mountains, Tanzania

Coleoptera diversity at the family level was investigated along the Kihansi gorge near a 700 m high waterfall system which will be taken to hydropower use, and the current river flow will be diverted due to dam construction. The coleopteran communities of three micro-habitats: spray zone, forest site and riverine site were compared by sweepnetting and pitfall trap methods. The highest Coleopteran family level diversity was found in the spray zone where the Shannon–Weaver index of diversity was 0.71 (forest site 0.31; riverine site 0.50). Coleopterans were most abundant in the forest site where 44% of all sampled individuals were found (spray zone 31%; riverine site 23%). Most of less frequently recorded families were found in the spray zone. Coleoptera families were found to be unequally partitioned in all three micro-habitats. The highest percentage similarity index (85%) was found between forest and riverine sites (spray/forest 76%; spray/riverine 79%). Distributions of abundances of coleopteran families were significantly different between all studied habitats. The study revealed that the spray generated by the waterfall provide a special micro-habitat for Coleoptera. It is suggested that conservation efforts and monitoring in the study area using selected taxonomic indicator Coleopteran groups should be carried out in order to help to adjust mitigation measures.     

Sulfolobus acidocaldarius inorganic pyrophosphatase: structure, thermostability, and effect of metal ion in an archael pyrophosphatase.

The first crystal structure of an inorganic pyrophosphatase (S-PPase) from an archaebacterium, the thermophile Sulfolobus acidocaldarius, has been solved by molecular replacement and refined to an R-factor of 19.7% at 2.7 A. S-PPase is a D3 homohexameric protein with one Mg2+ per active site in a position similar to, but not identical with, the first activating metal in mesophilic pyrophosphatases (PPase). In mesophilic PPases, Asp65, Asp70, and Asp102 coordinate the Mg2+, while only Asp65 and Asp102 do in S-PPase, and the Mg2+ moves by 0.7 A. S-PPase may therefore be deactivated at low temperature by mispositioning a key metal ion. The monomer S-PPase structure is very similar to that of Thermus thermophilus (T-PPase) and Escherichia coli (E-PPase), root-mean-square deviations around 1 A/Calpha. But the hexamer structures of S- and T-PPase are more tightly packed and more similar to each other than they are to that of E-PPase, as shown by the increase in surface area buried upon oligomerization. In T-PPase, Arg116 creates an interlocking ionic network to both twofold and threefold related monomers; S-PPase has hydrophilic interactions to threefold related monomers absent in both E- and T-PPase. In addition, the thermostable PPases have about 7% more hydrogen bonds per monomer than E-PPase, and, especially in S-PPase, additional ionic interactions anchor the C-terminus to the rest of the protein. Thermostability in PPases is thus due to subtle improvements in both monomer and oligomer interactions.     

The Yersinia adhesin YadA collagen-binding domain structure is a novel left-handed parallel beta-roll

The crystal structure of the recombinant collagen-binding domain of Yersinia adhesin YadA from Yersinia enterocolitica serotype O:3 was solved at 1.55 A resolution. The trimeric structure is composed of head and neck regions, and the collagen binding head region is a novel nine-coiled left-handed parallel beta-roll. Before the beta-roll, the polypeptide loops from one monomer to the rest, and after the beta-roll the neck region does the same, making the transition from the globular head region to the narrower stalk domain. This creates an intrinsically stable 'lock nut' structure. The trimeric form of YadA is required for collagen binding, and mutagenesis of its surface residues allowed identification of a putative collagen-binding surface. Furthermore, a new structure-sequence motif for YadA beta-roll was used to identify putative YadA-head-like domains in a variety of human and plant pathogens. Such domains may therefore be a common bacterial strategy for avoiding host response.     

Cadmium in insects after ash fertilization

Ash fertilization of forests returns nutrients to forest ecosystems and has a positive effect on soil pH, but it also may elevate Cd concentrations of forest biota. Cadmium concentrations of some forest insects ( Formica ants, carabids and Coleopteran larvae from decaying wood) were investigated in southern Finland, where two plots were fertilized with wood ash, while two other plots represented unfertilized control plots. In ants, mean Cd concentration was 3.6 ± 1.4 mg/kg, with nest workers having significantly higher concentrations than workers trapped in pitfall traps. Concentrations at fertilized and unfertilized plots were similar. In carabid beetles, the average Cd concentration of Carabus glabratus was 0.44 ± 0.36 mg/kg, with no significant difference between control plots and fertilized plots. In another carabid beetle, Pterostichus niger , mean Cd concentration was higher at fertilized plots compared to control plots. We conclude that the variation of Cd concentrations in the insects studied is more efficiently controlled by species-specific differences than fertilization history of the forest floor.