Exploring a unique water ecosystem under long-term exposure to hexavalent chromium - An in situ study of natural diatom (Bacillariophyceae) communities.

This paper reports the third in a series of three studies of a unique aquatic phytobial consortium that developed in a polluted ditch situated near an old chromium waste landfill. The ditch is a specific ecological niche having increased loads of several chemical compounds, including extreme hexavalent chromium concentrations up to two thousand times the allowed limit (0.02 mg dm-3 in Poland) in the more polluted section B; the moderate concentrations in section A are twice the limit. We focus on the microscopic algae group of diatoms, one of the most important components of the phytobial consortium, and continue our novel attempt to analyze the bioremediation potential of the entire consortium under those environmental conditions. We used numerical methods to analyze differences in diatom biodiversity between sections A and B, and assessed the relations between diatoms and selected water chemistry properties, including hexavalent chromium, chlorides and sulphates, the latter two known to positively influence the resistance of algae to the impact of hexavalent chromium. We noted 37 diatom taxa in section A of the ditch and 30 in section B. The most frequently observed diatoms were cosmopolitan taxa and/or characteristic taxa of saline waters. Sulphates were the most important factor influencing the diatom composition in the ditch, explaining 52% of the total variability, followed by chlorides (30%) and hexavalent chromium (9%). Gomphonema acuminatum, Melosira varians and Nitzschia frustulum var. frustulum were found to be most resistant to hexavalent chromium and were selected for further experimental studies on their biotechnological usefulness.

The vaginal microflora changes in various stages of the estrous cycle of healthy female dogs and the ones with genital tract infections.

BACKGROUND: Inflammatory diseases of reproductive tract in bitches are a common problem in veterinary practice. The inflammation can lead to serious health problems. Research to determine the correlation between the health status of females, phase of the cycle, age and bacterial flora of the genital tract has been ongoing for years, but the results obtained by individual authors are often contradictory. RESULTS: A total of 39 dogs were included in this study. Ten were qualified to the 1st group with genital tract infections (8 in anestrus and 2 in proestrus) and 29 to the 2nd group without such infections (16 in anestrus, 9 in proestrus and 4 in diestrus). The most common bacterial isolates obtained from the vaginal tract of all dogs were Escherichia coli, Staphylococcus pseudintermedius and Streptococcus canis. The prevalence of Gram-negative rods (other than E. coli) was significantly higher in the group with genital tract infections versus healthy dogs. There was no presence of Chlamydiaceae, Chlamydia abortus and lactic acid-producing bacteria in tested swabs. CONCLUSIONS: Our study identified the most common bacteria in the genital tract of bitches. The total number of bacteria was almost the same in the healthy and infected dogs, as well as between the cycle stages. In our opinion, bacterial culturing of vaginal swab specimens from bitches without signs of genital disease is of little value. Furthermore, it should always be preceded by clinical examination and cytological examination of the vaginal epithelium.

Integrative Approach Helps Clarify Confusing Taxonomy of the Pseudopediastrum boryanum Species Complex (Chlorophyceae), Including Recognition of five Distinct Species.

Sixteen monoclonal strains classified into six morphotypes typical of, or close to, intraspecific taxa of Pseudopediastum boryanum, including P. alternans (ALT), P. boryanum var. boryanum (BOR), P. boryanum var. cornutum (COR), P. boryanum var. forcipatum (FOR), P. boryanum var. longicorne (LON), and P. boryanum var. perforatum (PER), were simultaneously subjected to phylogenetic (26S rDNA and rbcL cpDNA) and morphometric analyses. Marginal cell shape, coenobium and cell size, and granule density on the cell surface were analyzed statistically. The shapes of some morphotypes (BOR, COR, FOR, and PER) were also compared to the shapes of corresponding type illustrations. Pseudopediastrum boryanum var. boryanum, without any reliable morphological and phylogenetic data, appeared to be a questionable taxon that needs a neotype. The variety longicorne proved to be a complex taxon that should be split after morphometric data of more strains and of the corresponding lectotype are included in the statistical analysis. A new species, Pseudopediastrum oblongum, was described, and four varieties were elevated to the species level, which resulted in establishing new combinations, P. cornutum, P. forcipatum, P. perforatum, and P. subgranulatum. Reference sequences for the new species and combinations were obtained. The paleoecological value of P. boryanum sensu lato appeared to be limited by the relatively low percentage of marginal cells typical of particular varieties and a high risk of their misidentification in the light microscope. The shape of marginal cells seemed to be the best diagnostic feature. Granule density could be helpful to discriminate between certain taxa.

Assessing morphological congruence in Dinobryon species and their stomatocysts, including a newly established Dinobryon pediforme-stomatocyst connection.

The chrysophyte genus Dinobryon Ehrenberg consists of 44 taxa, which occur in freshwaters, rarely marine waters, mostly in temperate regions of the world. The taxa of Dinobryon produce characteristic solitary or dendroid colonies and resting stages called stomatocysts. Only 20 Dinobryon taxa have information on produced stomatocysts and only four stomatocysts are reliably linked with vegetative stages using modern identification standards employing scanning electron microscopy (SEM) analyses. In this study, an encysted material of Dinobryon pediforme (Lemmermann) Steinecke was collected in two lakes in contrasting regions of Poland. Light microscopy (LM) and scanning electron microscopy (SEM) analyses revealed that Dinobryon pediforme produces stomatocyst #61, Piatek J. that is described here as new morphotype following the International Statospore Working Group (ISWG) guidelines. This raises to five the number of reliable links between vegetative stages of Dinobryon species and corresponding stomatocysts. Phenotypic similarities between Dinobryon species and their stomatocysts, analysed for five reliably established links, showed no relationships in size and shape between loricas and stomatocysts belonging to the same species. The morphological characters of loricas and stomatocysts mapped onto the phylogenetic tree of the five Dinobryon species revealed only little congruence between their morphology and phylogenetic relationships.