Aeromonas spp.-mediated cell-contact cytotoxicity is associated with the presence of type III secretion system

In the study we examined the production of cytotonic and cytotoxic toxins and the presence of a type III secretion system (TTSS) in 64 Aeromonas spp. strains isolated from fecal specimens of patients with gastroenteritis. We observed that contact of the bacteria with host epithelial cells is a prerequisite for their cytotoxicity at 3 h incubation. Cell-contact cytotoxic activity of the strains was strongly associated with the presence of the TTSS. Culture supernatants of the strains induced low cytotoxicity effects at the same time of incubation. Cell-free supernatants of 61 (95%) isolates expressed cytotoxic activity which caused the destruction of HEp-2 cells at 24 h. Moreover, 44% strains were cytotonic towards CHO cells and 46% of strains invaded epithelial cells

Cronobacter sakazakii clinical isolates overcome host barriers and evade the immune response

Cronobacter sakazakii is the most frequently clinically isolated species of the Cronobacter genus. However the virulence factors of C. sakazakii including their ability to overcome host barriers remains poorly studied. In this study, ten clinical isolates of C. sakazakii were assessed for their ability to invade and translocate through human microvascular endothelial cells (HBMEC). Their ability to avoid phagocytosis in human macrophages U937 and human brain microglial cells was investigated. Additionally, they were tested for serum sensitivity and the presence of the Cronobacter plasminogen activation gene (cpa) gene, which is reported to confer serum resistance. Our data showed that the clinical C. sakazakii strains invaded and translocated through Caco-2 and HBMEC cell lines and some strains showed significantly higher levels of invasion and translocation. Moreover, C. sakazakii was able to persist and even multiply in phagocytic macrophage and microglial cells. All strains, except one, were able to withstand human serum exposure, the single serum sensitive strain was also the only one which did not encode for the cpa gene. These results demonstrate that C. sakazakii clinical host immune response indicating their capacity to cause diseases such as necrotizing enterocolitis (NEC) and meningitis. Our data showed for the first time the ability of C. sakazakii clinical isolates to survive and multiply within human microglial cells. Additionally, it was shown that C. sakazakii clinical strains have the capacity to translocate through the Caco-2 and HBMEC cell lines paracellularly

Quaternary Ostracoda of the southern Baltic Sea (Poland) : taxonomy, palaeoecology and stratigraphy

Wcelu odtworzenia zmian środowiskowych w późnym glacjale i w holocenie na terenie polskiej części południowego Bałtyku zbadano rozmieszczenie małżoraczków w osadach 85 rdzeni pochodzących zarówno z obszarów otwartego morza, jak również ze strefy przybrzeżnej. W badanych osadach znaleziono łącznie 30 gatunków, z których sześć okazało się nowymi dla czwartorzędu polskiej części Bałtyku. Najczęstszymi były gatunki słodkowodne: Candona neglecta (występująca aż w 52 rdzeniach), C. candida (w 31 rdzeniach) i Cytherissa lacustris (w 30 rdzeniach), a także gatunek holeuryhalinowy Cyprideis torosa (w 52 rdzeniach). Pierwotne zgrupowania późnego glacjału i wczesnego holocenu, zdominowane przez gatunki strefy profundalu/ sublitoralu jezior oligo-mezotroficznych (C. lacustris, C. neglecta, C. candida) lub gatunki charakterystyczne dla litoralu jezior (Darwinula stevensoni, Limnocythere inopinata, Ilyocypris decipiens), w środkowym i późnym holocenie zostały zastąpione zgrupowaniami zdominowanymi przez gatunki słonawowodne–morskie (Cyprideis torosa, Cytheromorpha fuscata). Odnotowane prawidłowości sukcesyjne fauny małżoraczków wskazują na fundamentalne zmiany środowiskowe Morza Bałtyckiego, kiedy to wody morskie wdarły się do basenu bałtyckiego, powodując przekształcenie zbiornika słodkowodnego w słonawowodne Morze Litorynowe. Uzyskane wyniki poszerzyły wnioski zawarte w opublikowanych danych dotyczących małżoraczków i przemian środowiskowych południowego Bałtyku

Faunal database of the Southern Baltic Quaternary deposits

The project aimed at creating a digital archive of species documented from the Quarternary deposits of the Southern Baltic Sea. The records are ordered and supplemented with diagnostic descriptions. Users interested in micro- and malacofauna can use the data in various applications (e.g., GIS). Besides, the database is also compatible with zoological specimen collections for museums, using a standard catalogue registry. The database was created in MS Visual FoxPro format. Access to the database (including browsing, searching and sorting options) is possible via a custom- made user interface application. The database is distributed on CD-ROM including also the necessary software. Because of its "open" character, the database will be systematically updated with new results of research on the Southern Baltic. The new faunistic database is designed as compatible with an already existing geological data base (Neptun) in the Marine Geology Branch of the Polish Geological Institute. Such cooperation will allow users to get additional information (lithology, petrography, etc.) concerning the studied samples of the Quaternary faunal remains

Comparison of the antagonistic effect of Trichoderma spp. and yeasts on pathogenic Fusarium spp. in in vitro conditions

Celem przeprowadzonego doświadczenia było porównanie antagonistycznego oddziaływania grzybów z rodzaju Trichoderma oraz grzybów drożdżoidalnych na patogeny z rodzaju Fusarium w warunkach in vitro. W badaniach wykorzystano dwa gatunki grzybów z rodzaju Trichoderma: T. viride i T. harzianum, dwa gatunki grzybów drożdżoidalnych: Candida albicans i Trichosporon pullulans oraz pięć gatunków patogenów z rodzaju Fusarium: F. culmorum, F. graminearum, F. poae, F. oxysporum oraz F. avenaceum. Testowane grzyby wyszczepiano parami na pożywkę PDA. Doświadczenie wykonane zostało w dwóch seriach różniących się temperaturą inkubacji grzybów (20ºC i 26ºC). Pomiary prowadzono mierząc średnicę kolonii grzybów. Stwierdzono, że antagonistami o najsilniejszym działaniu na patogeny były T. harzianum oraz T. viride. Najsłabsze oddziaływanie na rozwój Fusarium spp. wykazał T. pullulans. Temperatura nie wpłynęła istotnie na działanie grzybów z rodzaju Trichoderma spp., natomiast C. albicans wykazał większą aktywność antagonistyczną w wyższej temperaturze. Wśród patogenów najbardziej wrażliwe na działanie antagonistów były F. graminearum, F. avenaceum oraz F. oxysporum.The aim of the study was to compare an antagonistic activity of Trichoderma spp. and yeasts on pathogenic Fusarium spp. in in vitro conditions. Two Trichoderma species (T. viride and T. harzianum), two yeast species (Candida albicans and Trichosporon pullulans) and five Fusarium species (F. culmorum, F. graminearum, F. poae, F. oxysporum and F. avenaceum ) were tested. Fungi were inoculated in pairs on PDA plates and incubated in two temperatures: 20ºC and 26ºC. The fungi diameter was measured. T. harzianum and T. viride affected the pathogens the most and T. pullulans the least. Incubation temperature did not affect Trichoderma spp. C. albicans was more active in the higher temperature. Among pathogens the most vulnerable were F. graminearum, F. avenaceum and F. oxysporum

Climate and environmental changes in the Late Glacial and Holocene in the Southern Baltic area based on investigations of malacofauna and ostracod assemblages : their influence on pre-existing biocoenoses

The climate changes and related crucial environmental changes in the Late Glacial and Holocene in the Southern Baltic area can be investigated by mollusc and ostracod analyses. It is well known that accumulation of mineral and biogenic sediments in the Southern Baltic area began in the Late Glacial. The process took place in cold tundra lakes and mires. The presence of lake basins is confirmed by seismoacoustic investigations and the resulting 3D spatial model. Lacustrine sediments contain an assemblage of molluscs and ostracod fauna represented by freshwater species indicating cold climate, such as: Armiger crista f. cristatus, Gyraulus laevis, Lymnaea peregra, Pisidium casertanum, Pisidium casertanum f. ponderosa, Pisidium milium, Pisidium nitidum, Pisidium obtusale f. lapponicum, Valvata cristata, Pisidium conventus, Candona candida, Candona neglecta, Cytherissa lacustris, Darwinula stevensoni and Cypridopsis vidua. The accumulation in freshwater reservoirs was continued during the Early Holocene. Besides cold freshwater species, sediments of that age also contain freshwater species of molluscs and ostracods that required higher temperature: Bithynia tentaculata, Physa fontinalis, Pisidium amnicum, Candona compressa and Metacypris cordata. It indicates a climate warming in the Preboreal period. These lake sediments were partly destroyed and covered by marine sands during the Middle and Upper Holocene. Good indicators of changing from a freshwater to marine environment are the following marine species found in the sediments: Hydrobia ulvae, Hydrobia ventrosa, Cerastoderma glaucum, Mytilus edulis, Macoma balthica, Cyprideis torosa and Cytheromorpha fuscata

A multidisciplinary study on the palaeoenvironmental history of the Resko Przymorskie Lake spit during the Late Glacial and Holocene (the southern Baltic coast, NW Poland)

The paper presents the results of sedimentological and biostratigraphical analyses from the Resko Przymorskie Lake spit (NW Poland), supported by radiocarbon datings. The study has aimed to recognize the geological structure of the spit and its base and to recognize the palaeoenivronmental changes. Nine sedimentary series composing the Resko Przymorskie Lake spit have been distinguished (I–IX). The oldest sediments are the Vistulian Glaciation till (series I) and fluvioglacial sand and gravel (series II). In the Early Holocene, in the study area there was a river valley (series III) followed by a shallow water basin (series IV), which was replaced by a peat bog (series V). In the Atlantic (7.4 ka cal BP), the water level rose (Littorina transgression) and accumulation of lagoonal sediments started (series VI). Biostratigraphic analysis of deposits in series VI indicates a marine influence. In the Atlantic and Subboreal, the spit moved southwards and fine sand (series VII) was deposited on lagoonal gyttja and silt (series VI). In the western part of the study area, peat accumulated (series VIII), dated at 6.7 ka cal BP (Late Atlantic). The youngest series IX is composed of aeolian fine sand in white dunes that formed in the last 400 years

Late glacial and holocene environmental changes in the Southern Baltic Sea area based on malacofauna investigations

Zmiany klimatyczne, a za tym daleko idące zmiany środowiska w późnym glacjale i holocenie na obszarze południowego Bałtyku mogą być wyjaśniane także przez badania fauny mięczaków. Na obszarze południowego Bałtyku w okresie późnego glacjału występowały gatunki słodkowodne wskazujące na klimat zimny, takie jak: Armiger crista f. cristatus, Gyraulus laevis, Lymnaea peregra, Pisidium casertanum, Pisidium casertanum f. ponderosa, Pisidium milium, Pisidium nitidum, Pisidium obtusale f. lapponicum, Valvata cristata, Pisidium conventus. Akumulacja jeziorna w słodkowodnych zbiornikach strefy przybrzeżnej kontynuowała się w okresie wczesnego holocenu. W tym czasie oprócz gatunków słodkowodnych, zimnolubnych pojawiły się gatunki mięczaków i małżoraczków słodkowodnych, o wyższych wymogach termicznych (Bithynia tentaculata, Physa fontinalis, Pisidium amnicum). Świadczy to o ociepleniu się klimatu w okresie preborealnym. Zrastanie przybrzeżnych zbiorników rozpoczęło się w okresie borealnym i trwało również w okresie atlantyckim. W tym czasie miały miejsce wlewy wód morskich do zbiorników. Wskaźnikiem tego jest liczne występowanie morskich gatunków takich jak: Hydrobia ulvae, Hydrobia ventrosa, Cerastoderma glaucum, Mytilus edulis, Macoma balthica. W osadach piaszczystych w okresie subborealnym i subatlantyckim zdecydowanie przeważała fauna morska

Sedimentary evidence of extreme storm surge or tsunami events in the southern Baltic Sea (Rogowo area, NW Poland)

The Baltic Sea is not typically considered as an area affected by tsunamis. However, during the Late Pleistocene and Holocene several tsunami events have been interpreted from the sedimentary record, mainly in Sweden and Estonia. Furthermore, on the southern coast of the Baltic Sea, there are historical accounts of catastrophical marine floodings called “der Seebär” (“the Sea Bear”). Their descriptions reveal many features typical for tsunami, but their genesis remained unknown and sedimentary evidence for such events has not been found. Here we provide evidence of sandy event layers from the area of Rogowo, NW Poland – the area of historical catastrophic storms as well as “der Seebär” events. The study area is a low-lying coastal plain with an average elevation of –0.5 to +0.5 m a.s.l., protected from the open sea by beach and coastal dune systems up to 5 m high. Sedimentological, micropalaeontological and geochemical analyses along with AMS 14C dating were applied to sedimentary successions seen in 5 major trenches and 198 sediment cores up to 1.5 m long. Two sandy layers were identified in the peat deposits that developed on the plain during the last ~2000 years. They reveal a number of typical features of tsunami deposits (significant lateral extent and thickness, rip-up clasts, chemical and micropalaeontological evidence of marine origin), however, 14C dating along with the historical accounts revealed that the major layer, extending at least 1.2 km from the modern coasts, was probably deposited by arguably the largest storm surge during the last 2000 years, which took place in 1497 AD. These storm deposits were likely formed during inundation of the low-lying coastal plain after major breaching of coastal dunes resulting in tsunami – like flow pattern and thus similar sedimentological effects. A discontinuous sand layer of younger age (18th century) and sharing similar properties to the previous one may be related to “der Seebär” event or another storm surge. The study revealed that the southern Baltic Sea coast may be affected by much greater coastal flooding than known from more recent accounts and observations. Thus, the presented geological record should be taken as an example of a worst-case scenario in coastal zone risk assessment from natural hazards. These events left sedimentary deposits that resemble tsunami deposits. It is likely that, in similar settings where storm surges cause unidirectional inundation of a coastal plain, it may not be possible to establish whether the resulting deposits were laid down from storms or tsunamis