Tree killing by herbicide producing ants for the establishment of pureTococa occidentalis populations in the Peruvian Amazon

Populations ofTococa occidentalis (Melastomataceae) and the inhabiting ants (Myrmelachista sp.) were observed for more than eight months in the Peruvian Amazon (Sira mountains). They represent a complex coevolutionary system: the plants offer shelter (leaf domatia, hollow stems) and food (leaf glands), whereas the ants kill all surrounding plants, including large trees up to 10 m, by chemical weapons. Experiments with exposed plants revealed a highly specialized way to attack meristematic tissue and leaf nervature, which leads to a quick decay of the plant individuals. The clearing of the vegetation by the ants allows theTococa population to expand mostly by vegetative shoots to large monocultures (up to 30 m in diameter) free from any other plant species. Artificially introduced plant individuals, from differentT. occidentalis populations, are regarded as a foreign species by the ants.The succession of such aTococa-Myrmelachista system begins with one or a few founder plants on a light place in the midst of the vegetation.Myrmelachista soon inhabits their host plants which otherwise would not survive and begin to clear the place from all foreign plant species.Tococa expands quickly, forming circle shaped populations. Distantly situated canopy trees shade theTococa population after a number of years and cause their decay. The whole place appears contaminated for years and no other plant can establish itself. Some of the consequences of these open places are erosion and a severe influence on the regeneration of the forest.     

Rehabilitation and management of a moderately deep-stratifying reservoir by the use of nutrient reduction and food-web management

As expected from its short renewal time, the hypertrophic Lingese Reservoir responded rapidly but incompletely to external nutrient reduction in 1993. Although there was a sudden decline in lake phosphorus and chlorophyll concentrations, the ‘turbid regime’ revealed resistance in this weakly stratified reservoir of intermediate depth. Draining the reservoir in autumn 1995 provided an unprecedented opportunity for sediment treatment—the phosphorus-rich surface layer was inverted and covered with deeper nutrient-poor layers—and removal of the dense cyprinid fish stock which had not responded to sewage diversion, at least in the short term. Commencing with refilling in 1999, a new fish stock was built up from 2000 by only stocking predators (fingerlings of pike, pike-perch and larger specimens of rainbow-trout in the first years) in combination with catch restrictions. Concomitantly, with the appearance of daphnids in 1999, a ‘clear water regime’ was established and lake water phosphorus concentrations decreased at unchanged external loading. Reduced zooplanktivory as well as reduced fish-mediated phosphorus release from the sediments were driving mechanisms behind successful reduction of internal loading and achievement of a ‘clear water regime’. Hence, phosphorus concentrations were revealed to be a response variable not only to input management but also to food-web management. As the development of cyprinid dominance was prevented in the long-term, there is ample evidence that the fish community responded to the applied management measures as expected featuring successful food-web management. Overall, the biological structure was revealed to be of major importance for lake phosphorus availability and turbidity as in shallow lakes, without, however, the establishment of macrophyte dominance.     

Histochemistry of glycoconjugates in the nasolabial skin of the Japanese serow (Capricornis crispus, Artiodactyla, Mammalia) with special reference to glandular structures

The histochemistry of glycoconjugates in the nasolabial skin of the Japanese serow ( Capricornis crispus ) was studied by light microscopic histochemical methods, particularly lectin histochemistry. The eccrine glands present exhibited neutral and acidic glycoconjugates with different saccharide residues (alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine, alpha-D-galactose and N-acetyl-neuraminic acid) especially in the cells of the secretory acini, the free surface of the collecting duct cells also showed distinct positive reactions with most of the histochemical methods. The thick epidermis of the nasolabial skin contained smaller amounts of glycoproteins. The results obtained are discussed with regard to possible functions of the glandular secretions. This substance mixture may particularly improve water retention on the skin surface, and protect against physical damage as well as microbial contamination. There seem to be no basic differences of muzzle functions between wild and domesticated bovine species.     

Ethidium monoazide and propidium monoazide for elimination of unspecific DNA background in quantitative universal real-time PCR

Unspecific background DNA in quantitative universal real-time PCR utilizing a hydrolysis probe was completely suppressed by the addition of EMA or PMA to the PCR mix via cross-linking of the dyes to DNA during 650 W visible light exposure. The proposed procedure had no effect on the sensitivity of the real-time PCR reaction.     

Nucleotide pools of growing,synchronized and stressed cultures of Saccharomyces cerevisiae

High pressure liquid chromatography has been used to study the acid soluble nucleotide pool of Saccharomyces cerevisiae under different conditions of growth. ATP, ADP, AMP, NAD, GTP, UTP, UDP, CTP, CDP, and UDP-sugars plus UMP could be separated and were found in concentrations higher than 0.1 mumol per g yeast cell dry weight (= detection limit). During glucose-limited continuous culture the levels of individual nucleotides depended on the growth rate, which was most pronounced with pyrimidine (uridine, cytidine) nucleotides. The energy charge (E.C.) remained high (0.9) at all growth rates (0.07-0.3 h-1). During synchronized growth at a constant growth rate (0.11 h-1) almost all nucleotide levels and the E.C. remained at constant values with the only exception of UDP-sugars and UMP of which increased levels were found during the phase of budding. Under conditions of metabolic stress (addition of antimycin A, deoxyglucose plus iodoacetate) pronounced changes in the levels of purine (adenine and guanine) nucleotides and the E.C. were observed. All other nucleotides were less influenced by these conditions. Only under these conditions IMP accumulation was observed. The results strongly argue against the significance of purine nucleotide or E.C. measurements under viable conditions. In contrast, changes in the levels of pyrimidine nucleotides seem to be indicative of changes in the flux through the metabolic pathways where they act as coenzymes.     

First known gall midge (Diptera: Cecidomyiidae) from Arecaceae: Normanbyomyia fructivora gen. & sp. n. damaging fruit of the black palm, Normanbya normanbyi, in tropical Australia

Abstract  A new species of gall midge, Normanbyomyia fructivora gen. & sp. n., was found infesting flowers and fruit of the black palm, Normanbya normanbyi (Arecaceae), in the tropical forest of north-eastern Australia. Larvae of the gall midge live between the perianth and the young fruit causing abnormal fruit growth. Infested fruit are substantially smaller than healthy ones, fall off prematurely and decay on the ground without producing seedlings. Normanbyomyia , a new genus erected for the new species is placed within the supertribe Lasiopteridi and is characterised by a conspicuous female abdominal segment 8 that is inflated and strongly sclerotised, and wide male parameres that loosely sheath the aedeagus and bear no papillae. A key to Australian Lasiopteridi is provided. The new species becomes the first described gall midge that feeds on a plant from the palm family, Arecaceae.