Protoxenidae fam. nov. (Insecta, Strepsiptera) from Baltic amber — a 'missing link' in strepsipteran phylogeny

A male specimen of a new strepsipteran genus and species ( Protoxenos janzeni gen. et sp. nov.) and family (Protoxenidae fam. nov.) found in Baltic amber is described and illustrated. It shows features which are apparently more plesiomorphic than in hitherto known strepsipterans, such as laterally inserted eight-segmented antennae, very robust mandibles with a broad base, a prominent galea, a comparatively short, transverse metapostnotum, hindwings that are feebly extended in a rostrocaudal direction, and equally sclerotized abdominal tergites and sternites. Based on a cladistic analysis of 46 characters of males of 11 genera and three outgroup taxa, P. janzeni is the sister group of all other known strepsipterans, and Mengea the sister group of Strepsiptera s.s . Eoxenos is the sister group of the remaining extant strepsipterans and Mengenillidae is therefore paraphyletic. Newly established groundplan features of Strepsiptera will facilitate the clarification of the systematic position of the Order in future studies.     

Lysosomes of Toxoplasma gondii and Their Possible Relation to the Host-Cell Penetration of Toxoplasma Parasites

Lysosome-like structures of Toxoplasma gondii were observed by means of vital staining with acridine orange and by the Gomori technique. These structures were found scattered over the cytoplasm but were often located at one end of the parasite. In comparison with parasites of the inoculum used for infecting HeLa cell cultures, the toxoplasma which had penetrated the HeLa cells revealed a markedly lower percentage of parasites showing lysosomal staining. After the penetration, the number of parasites with demonstrable lysosomes increased successively and, at the time for release of newly formed parasites (at 24 hr), the majority of the parasites demonstrated lysosome-like bodies in the cytoplasm. The observations are discussed with special reference to the mechanism of host-cell penetration.     

Human-induced Trophic Cascades and Ecological Regime Shifts in the Baltic Sea

Abstract The ecosystems of coastal and enclosed seas are under increasing anthropogenic pressure worldwide, with Chesapeake Bay, the Gulf of Mexico and the Black and Baltic Seas as well known examples. We use an ecosystem model (Ecopath with Ecosim, EwE) to show that reduced top-down control (seal predation) and increased bottom-up forcing (eutrophication) can largely explain the historical dynamics of the main fish stocks (cod, herring and sprat) in the Baltic Sea between 1900 and 1980. Based on these results and the historical fish stock development we identify two major ecological transitions. A shift from seal to cod domination was caused by a virtual elimination of marine mammals followed by a shift from an oligotrophic to a eutrophic state. A third shift from cod to clupeid domination in the late 1980s has previously been explained by overfishing of cod and climatic changes. We propose that the shift from an oligotrophic to a eutrophic state represents a true regime shift with a stabilizing mechanism for a hysteresis phenomenon. There are also mechanisms that could stabilize the shift from a cod to clupeid dominated ecosystem, but there are no indications that the ecosystem has been pushed that far yet. We argue that the shifts in the Baltic Sea are a consequence of human impacts, although variations in climate may have influenced their timing, magnitude and persistence. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Identification of genetic regions of importance for reproductive performance in female mice

Both environmental and genetic factors can dramatically affect reproductive performance in mice. In this study we have focused on the identification of genetic regions, quantitative trait loci (QTL), which affect the breeding capacity of female mice. We have identified polymorphic microsatellite markers for the mouse strains used and performed a genomewide scan on 237 females from a gene-segregating backcross between a high breeder and a relatively poor breeder. The high-breeder mouse strain we used is the inbred NFR/N mouse (MHC haplotype H-2q), which has extraordinary good breeding properties. The moderate breeder chosen for F(1) and N2 progeny was B10.Q, which is a genetically well-characterized MHC-congenic mouse of the H-2q haplotype. Each of the 237 females of the N2 generation was allowed to mate twice with MHC-congenic B10.RIII (H-2r) males and twice with B10.Q males. A predetermined number of phenotypes related to reproductive performance were recorded, and these included litter size, neonatal growth, and pregnancy rate. Loci controlling litter size were detected on chromosomes 1 (Fecq3) and 9 (Fecq4). The neonatal growth phenotype was affected by Fecq3 and a locus on chromosome 9 (Neogq1). On chromosome 11 two loci affecting the pregnancy rate (Pregq1 and Pregq2) were identified. Furthermore, on chromosomes 13 and 17 we found loci (Pregq3 and Pregq4) influencing the outcome of allogeneic pregnancy (allogeneic by means of MHC disparity between mother and fetuses). A locus on chromosome 1 affecting maternal body weight was also identified and has been denoted Bwq7. It is well known that reproductive performance is polygenically controlled, and the identification of the major loci in this complex process opens the possibility of investigating the natural genetic control of reproduction.     

Structural characteristic,pH and thermal stabilities of apo and holo forms of caprine and bovine lactoferrins

Apo and holo forms of lactoferrin (LF) from caprine and bovine species have been characterized and compared with regard to the structural stability determined by thermal denaturation temperature values (T _m), at pH 2.0–8.0. The bovine lactoferrin (bLF) showed highest thermal stability with a T _m of 90 ± 1°C at pH 7.0 whereas caprine lactoferrin (cLF) showed a lower T _m value 68 ± 1°C. The holo form was much more stable than the apo form for the bLF as compared to cLF. When pH was gradually reduced to 3.0, the T _m values of both holo bLF and holo cLF were reduced showing T _m values of 49 ± 1 and 40 ± 1°C, respectively. Both apo and holo forms of cLF and bLF were found to be most stable at pH 7.0. A significant loss in the iron content of both holo and apo forms of the cLF and bLF was observed when pH was decreased from 7.0 to 2.0. At the same time a gradual unfolding of the apo and holo forms of both cLF and bLF was shown by maximum exposure of hydrophobic regions at pH 3.0. This was supported with a loss in α-helix structure together with an increase in the content of unordered (aperiodic) structure, while β structure seemed unchanged at all pH values. Since LF is used today as fortifier in many products, like infant formulas and exerts many biological functions in human, the structural changes, iron binding and release affected by pH and thermal denaturation temperature are important factors to be clarified for more than the bovine species.     

Function,size and form of the gastrointestinal tract of the collared <Emphasis Type="Italic">Pecari tajacu</Emphasis> (Linnaeus 1758) and white-lipped peccary <Emphasis Type="Italic">Tayassu pecari</Emphasis> (Link 1795)

The peccary digestive tract is characterised by an elaborate forestomach. In order to further characterise the digestive function of peccaries, we report body mass, digestive organ mass, content mass of the gastrointestinal tract compartments and their length and width, as well as liver, parotis and mandibular gland mass. Our data on eleven collared and four white-lipped peccaries suggest that peccaries have a small relative stomach volume compared to other foregut fermenters, which implies a comparatively lower fermentative capacity and thus forage digestibility. The forestomach could enable peccaries to deal, in conjunction with their large parotis glands, with certain plant toxins (e.g. oxalic acid). The finding of sand being trapped in the forestomach blindsacs could indicate a disadvantage of the peccary forestomach design. The relevance of the forestomach to peccaries remains enigmatic.     

Effects of nighttime low frequency noise on the cortisol response to awakening and subjective sleep quality

The effects of night-time exposure to traffic noise (TN) or low frequency noise (LFN) on the cortisol awakening response and subjective sleep quality were determined. Twelve male subjects slept for five consecutive nights in a noise-sleep laboratory. After one night of acclimatisation and one reference night, subjects were exposed to either TN (35dB L(Aeq), 50dB L(Amax)) or LFN (40dB L(Aeq)) on alternating nights (with an additional reference night in between). Salivary free cortisol concentration was determined in saliva samples taken immediately at awakening and at three 15-minute intervals after awakening. The subjects completed questionnaires on mood and sleep quality. The awakening cortisol response on the reference nights showed a normal cortisol pattern. A significant interaction between night time exposure and time was found for the cortisol response upon awakening. The awakening cortisol response following exposure to LFN was attenuated at 30 minutes after awakening. Subjects took longer to fall asleep during exposure to LFN. Exposure to TN induced greater irritation. Cortisol levels at 30 minutes after awakening were related to "activity" and "pleasantness" in the morning after exposure to LFN. Cortisol levels 30 minutes after awakening were related to sleep quality after exposure to TN. This study thus showed that night time exposure to LFN may affect the cortisol response upon wake up and that lower cortisol levels after awakening were associated with subjective reports of lower sleep quality and mood.