Valve movement of the freshwater mussel Anodonta anatina: a reciprocal transplant experiment between lake and river

The effects of source and caging on the valve movements of the freshwater unionid mussel (Anodonta anatina) were studied in a reciprocal transplant experiment between a lake and its outflow. Caged mussels were moved and compared with those remaining in their natural environment on the lake or river bottom. At both sites, the mussels from the study site and the transplanted mussels from the opposite site were monitored simultaneously. In river the averaged weighted valve openness was higher and the number of valve movements was lower than in the lake. The mussels monitored in the lake exhibited a diurnal rhythm of valve movements which differed between the lake-bottom and the caged animals. Caging was found to increase valve openness. On the other hand, little variation appeared in valve openness between caged and bottom animals in the river, where diurnal rhythms were almost nonexistent. In the river the valve movements were more variable in respect to time than in the lake.     

Biology of Leipothrix dipsacivagus (Acari: Eriophyidae), a candidate for biological control of invasive teasels (Dipsacus spp.)

The present study describes key aspects of the biology of Leipothrix dipsacivagus, an eriophyid mite that is under study as a biological control candidate of Dipsacus fullonum and D. laciniatus (Dipsacaceae). Preliminary host-specificity tests have shown that it can develop and reproduce only on Dipsacus spp. (teasels). Studies were conducted in a laboratory at 26 ± 2^oC with 16 h of light per day. Mites for the stock colony were collected from D. laciniatus in Klokotnitsa, Bulgaria and reared on rosettes of D. laciniatus in the laboratory. Unfertilized L. dipsacivagus females reared in isolation from the juvenile stage produced male offspring only, while progeny of fertilized females were of both sexes, suggesting arrhenotokous parthenogenesis with haplodiploid sex determination. Experiments were designed to compare male progeny from fertilized females to males from unfertilized females and to compare males and females from fertilized females. Male progeny of virgin mothers had significantly longer durations of active immature stages and total egg-to-adult period than male progeny of fertilized females. Female progeny had significantly longer durations of egg incubation, active immature stages and egg-to-adult period than male progeny from fertilized mothers. Adult longevity was significantly greater in females than in males. Fertilized females produced significantly more eggs per day and overall than virgin females. The results of this study suggest that fertilization status of L. dipsacivagus females can affect both their own fecundity and the development of their male progeny.     

Laboratory and field experimental evaluation of host plant specificity of Aceria solstitialis, a prospective biological control agent of yellow starthistle

Centaurea solstitialis (yellow starthistle, Asteraceae) is an invasive annual weed in the western USA that is native to the Mediterranean Region and is a target for classical biological control. Aceria solstitialis is an eriophyid mite that has been found exclusively in association with Ce. solstitialis in Italy, Greece, Turkey and Bulgaria. The mite feeds on leaf tissue and damages bolting plants, causing stunting, witch’s broom and incomplete flower development. Field experiments and laboratory no-choice and two-way choice experiments were conducted to assess host plant specificity of the mite in Bulgaria. Mites showed the highest degree of host specificity in the field and lowest in the no-choice experiments. In the field, highest densities of mites occurred on Ce. solstitialis and Ce. cyanus (bachelor’s button), and either no mites or trace numbers occurred on the other test plants: Ce. diffusa (diffuse knapweed), Carthamus tinctorius (safflower) and Cynara scolymus (artichoke). In no-choice experiments, mites persisted for 60 days on Ce. diffusa, Ce. cyanus, Ce. solstitialis, Ca. tinctorius and Cy. scolymus, whereas in two-way choice experiments mites persisted on 25% of Cy. scolymus plants for 60 days and did not persist on Ca. tinctorius beyond 40 days. The eight other species of plants that were tested in the laboratory were less suitable for the mite. These results suggest that although A. solstitialis can persist on some nontarget plants for as long as 60 days in the laboratory, it appears to be much more specific under natural conditions, and warrants further evaluation as a prospective biological control agent.     

Thoracic intramedullary sarcoidosis mimicking an intramedullary tumor

Sarcoidosis is a chronic, systemic granulomatous reticulosis of unknown origin, characterized by formation of hard tubercles and noncaseatinggranulomas. Since other infectious diseases such as berylliosis, mycobacterium and fungal infections may present with a noncaseating granulomas, histological diagnosis of sarcoidosis is made using the elimination method. Central nervous system manifestations of sarcoidosis may be present in 5-10% of the cases involving cranial nerves, leptomeninges and third ventricle respectively. Any part of the central nervous system can be affected. Involvement of spinal cord in sarcoidosis is extremely rare and presents with only 0.3-0.4% in patients with systemic sarcoidosis. Intramedullary sarcoidosis is a rare first manifestation of the disease and it can mimic an intramedullary tumor, which is often manifested with symptoms that initiate from spinal cord compression, resulting in paraparesis, sensory disorders and sphincter dysfunction. We present a case of intramedullary sarcoidosis that mimics a tumor of the thoracic spinal cord. Clinical features, neuroradiological, pathohistological findings, laboratory analysis and surgical treatment of such a rare entity are being discussed.     

Drosophila melanogaster transferrin. Cloning, deduced protein sequence, expression during the life cycle, gene localization and up-regulation on bacterial infection.

Drosophila melanogaster transferrin cDNA was cloned from an ovarian cDNA library by using a PCR fragment amplified by two primers designed from other dipteran transferrin sequences. The clone (2035 bp) encodes a protein of 641 amino acids containing a signal peptide of 29 amino acids. Like other insect transferrins, Drosophila transferrin appears to have a functional iron-binding site only in the N-terminal lobe. The C-terminal lobe lacks iron-binding residues found in other transferrins, and has large deletions which make it much smaller than functional C-terminal lobes in other transferrins. In-situ hybridization using a digoxigenin labeled transferrin cDNA probe revealed that the gene is located at position 17B1-2 on the X chromosome. Northern blot analysis showed that transferrin mRNA was present in the larval, pupal and adult stages, but was not detectable in the embryo. Iron supplementation of the diet resulted in lower levels of transferrin mRNA. When adult flies were inoculated with bacteria (Escherichia coli), transferrin mRNA synthesis was markedly increased relative to controls.     

Assessment of nutrient limitation in Rijeka Bay, NE Adriatic Sea, using miniaturized bioassay

In this paper we consider the trophic state and ambient nutrient limitation by the trophic index (TRIX) calculation and nutrient enrichment bioassay using the diatom Phaeodactylum tricornutum at two differently eutrophicated NE coastal Adriatic locations (in the Rijeka Bay area). The first station in Rijeka Port had significantly higher concentrations of dissolved inorganic nutrients and TRIX indices (up to 7.53) than the station near Opatija. The DIN/TP ratios in Rijeka Port were lower (11.03 to 44.47) than those in Opatija (38.67 to 82.00), indicating P limitation in Opatija. The nutrient enrichment bioassays revealed P as the key limiting nutrient for the diatom growth at both sites. In addition, silica limitation was found in all water samples with the exception of the surface water samples in Rijeka Port. Nitrogen limitation was rarely evident.     

Ecology and taxonomy of potentially toxic Pseudo-nitzschia species in Lim Bay (north-eastern Adriatic Sea)

The population dynamics of Pseudo-nitzschia in relation to environmental factors was investigated from March 2002 to July 2008 in Lim Bay, in the north-eastern Adriatic Sea. Domoic acid was monitored in the breeding population of Mytilus galloprovincialis from 2005 to 2008. The principal-component analysis of environmental parameters showed that the system is mostly temperature driven. The phytoplankton community was mainly composed of diatoms. Pseudo-nitzschia was the dominant diatom, present in 60% of samples, with a maximum (1.6 × 10⁶ cells L⁻¹) contribution up to 97% of the total diatom abundance. Morphological analysis revealed Pseudo-nitzschia manii and potentially toxic Pseudo-nitzschia pseudodelicatissima, Pseudo-nitzschia pungens, Pseudo-nitzschia fraudulenta and Pseudo-nitzschia calliantha as the dominant species in blooms. Pseudo-nitzschia abundance positively correlated to temperature, phosphate and ammonia in accordance with its maximal abundance in the summer/autumn period when fish farms had a maximum impact on the environment. Domoic acid was detected in M. galloprovincialis in concentrations below regulatory limits, ranging from 0.097 to 0.8721 μg g⁻¹ in five cases from April to October 2005 in Lim Bay, but so far it is not clear which of the species was responsible for DA production. This study is also the first record of P. manii, P pungens and P. fraudulenta species in the Adriatic Sea.     

Negative correlation between maorophage proooagulant and migraion ability in the course of inflammation

The importance of macrophage procoagulant activity (PCA) to cell migration is presumed. In this study we assayed the relationship between the two functions in guinea-pig peritoneal resident macrophages and cells elicited by a sterile inflammation induction, which lasted up to 6 days. The findings pointed to an in vivo induction of PCA in macrophages, which declined with time during inflammation. A clear negative correlation between PCA and random migration ability was demonstrated. Our results suggest that the local induction of coagulation by macrophages may immobilize the cells at the site of inflammation.     

Phytoplankton population density and volume as indicators of eutrophication in the eastern part of the Adriatic Sea

Population density and volume-biomass of microplankton, nanoplankton and total phytoplankton were analyzed at 14 stations along the eastern part of the Adriatic Sea. Based upon data frequency distribution, four categories of ecosystems were established in the investigated area. Criteria for ecosystem categorization and biological evaluation of eutrophication are proposed.