Lipopeptide Biosurfactant Pseudofactin II Induced Apoptosis of Melanoma A 375 Cells by Specific Interaction with the Plasma Membrane

In the case of melanoma, advances in therapies are slow, which raises the need to evaluate new therapeutic strategies and natural products with potential cancer cell inhibiting effect. Pseudofactin II (PFII), a novel cyclic lipopeptide biosurfactant has been isolated from the Arctic strain of Pseudomonas fluorescens BD5. The aim of this study was to investigate the effect of PFII on A375 melanoma cells compared with the effect of PFII on Normal Human Dermis Fibroblast (NHDF) cells and elucidate the underlying mechanism of PFII cytotoxic activity. Melanoma A375 cells and NHDF cells were exposed to PFII or staurosporine and apoptotic death was assessed by monitoring caspase 3-like activity and DNA fragmentation. From time-dependent monitoring of lactate dehydrogenase (LDH) release, Ca²⁺ influx, and a correlation between Critical Micelle Concentration (CMC) we concluded that cell death is the consequence of plasma membrane permeabilisation by micelles. This finding suggests that pro-apoptotic mechanism of PFII is different from previously described cyclic lipopeptides. The mechanism of PFII specificity towards malignant cells remains to be discovered. The results of this study show that PFII could be a new promising anti-melanoma agent.     

Patterns of sclerobiont colonization on the rugose coral Schlotheimophyllum patellatum (Schlotheim, 1820) from the Silurian of Gotland,Sweden

Analysis of mushroom-shaped rugose corals Schlotheimophyllum patellatum (Schlotheim, 1820) from the Silurian (Upper Visby Beds, Lower Wenlock, Sheinwoodian) of Gotland, Sweden, showed that they were colonized on both the upper (exposed) and lower (cryptic) sides by a variety of encrusting and boring (sclerobiont) biotas, represented by 10 taxa and at least 23 species. Bryozoans and microconchid tubeworms, the most abundant encrusters, dominated on the cryptic undersides of the corals, while the dominant endobionts responsible for Trypanites borings overwhelmingly dominated the exposed surfaces. Except for cnidarian sphenothallids, which were exclusive colonizers of the underside of only one coral host, no other encrusters could be referred to as obligate cryptobionts. Because the upper surface of these corals was likely covered by soft-tissues during life, in specimens lifted off the sea-floor sclerobionts must have settled on the cryptic sides first. They could colonize the upper side only after the coral’s death, unless it was covered by sediment as could be the case in some flat specimens. With time, the space on the underside of the coral skeleton may have progressively been filled by sediment as well, precluding further colonization by sclerobionts. In that respect, the colonization patterns of these corals by encrusters and borers were controlled by the complex interplay of environmental factors, sclerobiont dynamics and coral growth in a given Silurian habitat. Compared with Silurian stromatoporoid hosts, the sclerobiont diversity and abundance noted on the Schlotheimophyllum corals may be regarded as representative for the Silurian as a whole.     

Assessing avian diversity and community composition along a successional gradient in traditional Lacandon Maya agroforests

Evidence regarding the ability of agroforests to conserve biological diversity has been mixed; they tend to maintain avian communities with species richness similar to that of undisturbed forest ecosystems but generally do not completely preserve community composition. Using a combination of occupancy modeling and non-metric multidimensional scaling on point-count data, we assessed changes in avian community diversity and composition along a successional gradient in traditional Lacandon Maya agroforests and compared them to protected areas in the region. Bird species richness and diversity in Lacandon agroforests peaked in early secondary forest stages. These agroforests' mean Shannon–Weiner diversity was 5% higher than that of nearby protected areas, but their species richness was similar. Community composition in Lacandon agroforests changed throughout succession, with earlier stages supporting communities distinctly characterized by generalist species, while subsequent, less-intensively managed stages tended to support more forest-dwellers. The bird community observed in even the most mature secondary forest stages in Lacandon agroforests differed from that of undisturbed rain forest ecosystems. These results demonstrate the potential of traditional Lacandon agroforestry management to conserve avian biodiversity while ensuring food sovereignty for farmers. However, because the community composition of early-successional stages was different than later stages, shortening fallow cycles and reducing forest cover to increase agricultural production will limit the species this system can support. This study illustrates the value of incorporating traditional agroecosystems into conservation planning as well as maintaining protected areas, because the latter serve as refugia for species that require undisturbed forest habitat in an agroecological matrix.     

Large BRCA1 and BRCA2 genomic rearrangements in Polish high-risk breast and ovarian cancer families

BRCA1 and BRCA2 are two major genes associated with familial breast and ovarian cancer susceptibility. In Poland standard BRCA gene test is usually limited to Polish founder BRCA1 mutations: 5382insC, C61G and 4153delA. To date, just a few single large genomic rearrangements (LGRs) of BRCA1 gene have been reported in Poland. Here we report the first comprehensive analysis of large mutations in BRCA1 and BRCA2 genes in this country. We screened LGRs in BRCA1 and BRCA2 genes by multiplex ligation-dependent probe amplification in 200 unrelated patients with strong family history of breast/ovarian cancers and negative for BRCA1 Polish founder mutations. We identified three different LGRs in BRCA1 gene: exons 13-19 deletion, exon 17 deletion and exon 22 deletion. No LGR was detected in BRCA2 genes. Overall, large rearrangements accounted for 3.7 % of all BRCA1 mutation positive families in our population and 1.5 % in high-risk families negative for Polish founder mutation.     

Short-term growth of meadow fescue with atmospheric CO2 enrichment decreases freezing tolerance, modifies photosynthetic apparatus performance and changes the expression of some genes during cold acclimation

The objective of this study was to assess the effect of an elevated atmospheric CO₂ molar ratio on freezing tolerance, photosynthetic apparatus performance and expression of CBF6, Cor14b and LOS2 in meadow fescue (Festuca pratensis Huds.). It was shown that cold acclimation under a CO₂ molar ratio of 800 μmol mol(air)^?1 decreased the freezing tolerance of meadow fescue when compared to the ambient CO₂ level. This effect was not related either to changes observed in PSII redox state or to photosynthetic acclimation to cold, which was in fact more effective at an elevated CO₂ level. The decrease in freezing tolerance was linked to changes in the expression of CBF6 and LOS2 genes, whereas the protective effect on photosynthetic apparatus was connected with the activation of a non-photochemical mechanism of photoprotection as well as upregulation of FpCOR14b expression.     

Extracellular Signal-regulated Kinase 5 (ERK5) Mediates Prolactin-stimulated Adult Neurogenesis in the Subventricular Zone and Olfactory Bulb

Prolactin-stimulated adult neurogenesis in the subventricular zone (SVZ) and olfactory bulb (OB) mediates several reproductive behaviors including mating/pregnancy, dominant male pheromone preference in females, and paternal recognition of offspring. However, downstream signaling mechanisms underlying prolactin-induced adult neurogenesis are completely unknown. We report here for the first time that prolactin activates extracellular signal-regulated kinase 5 (ERK5), a MAP kinase that is specifically expressed in the neurogenic regions of the adult mouse brain. Knockdown of ERK5 by retroviral infection of shRNA attenuates prolactin-stimulated neurogenesis in SVZ-derived adult neural stem/progenitor cells (aNPCs). Inducible erk5 deletion in adult neural stem cells of transgenic mice inhibits neurogenesis in the SVZ and OB following prolactin infusion or mating/pregnancy. These results identify ERK5 as a novel and critical signaling mechanism underlying prolactin-induced adult neurogenesis.     

Oviposition behaviour of the soil mite Pergamasus brevicornis (Acari: Parasitidae)

We observed the oviposition behaviour of the soil mite Pergamasus brevicornis Berlese (Acari: Parasitidae) using continuous video-monitoring. Oviposition consisted of six sequential phases. The first phase (I) involved inspection of the substrate. In the second phase (II) there were rhythmic movements of the first pair of legs and slight reciprocating movements of the body. The third (III) was a resting phase. In the fourth phase (IV) the gnathosoma was lowered and the body was raised. In the next phase (V) there were two sub-phases. During the first (Va), the female held the egg below the gnathosoma. In the second sub-phase (Vb), the gnathosoma moved up holding the egg, which was then placed on the substrate. The last phase (VI) involved intense ‘cleaning’ movements of the chelicerae and palps. During Va a protective external eggshell structure is gradually formed, involving a phase where the egg shell is sticky. After moving the egg to the substrate, the female freed her palps and chelicerae from the sticky egg shell and cleaned her gnathosomal appendages. Phases II–V took on average 207 ± 69 s.     

Interpretation of the invertebrate-based BMWP-PL index in a gravel-bed river: insight from the Polish Carpathians

Like its British prototype (Biological Monitoring Working Party score system), the Polish benthic invertebrate-based BMWP-PL index is commonly regarded as an indicator of river water quality. This interpretation of the index has been verified in a study of the gravel-bed Bia?a River. Benthic macroinvertebrates were sampled at 10 sites and compared in one channelized and one unmanaged cross-section per site. The resulting taxa richness and BMWP-PL index scores were compared with water quality and physical habitat characteristics in the cross-sections. Channelized and unmanaged cross-sections clearly differed in their physical habitat conditions, and water quality characteristics mostly varied in the downstream direction. Particular cross-sections hosted between 3 and 26 invertebrate taxa, with the respective BMWP-PL scores indicating the water in the surveyed cross-sections varied between high and poor quality. However, the BMWP-PL scores were unrelated to physicochemical characteristics of the river water, which consistently pointed to high water quality. Instead, the scores were significantly related to several physical habitat variables, with the number of low-flow channels in a cross-section explaining the largest proportion of the variance in the index values. The relationship of the scores with the complexity of flow pattern in the river and a lack of their dependence on physicochemical water characteristics show that the BMWP-PL index should not be regarded as an indicator of water quality but rather as an indicator of the ecological status of rivers, dependent both on their hydromorphological and water-quality characteristics.     

Redox signals as a language of interorganellar communication in plant cells

Plants are redox systems and redox-active compounds control and regulate all aspects of their life. Recent studies have shown that changes in reactive oxygen species (ROS) concentration mediated by enzymatic and non-enzymatic antioxidants are transferred into redox signals used by plants to activate various physiological responses. An overview of the main antioxidants and redox signaling in plant cells is presented. In this review, the biological effects of ROS and related redox signals are discussed in the context of acclimation to changing environmental conditions. Special attention is paid to the role of thiol/disulfide exchange via thioredoxins (Trxs), glutaredoxins (Grxs) and peroxiredoxins (Prxs) in the redox regulatory network. In plants, chloroplasts and mitochondria occupying a chloroplasts and mitochondria play key roles in cellular metabolism as well as in redox regulation and signaling. The integrated redox functions of these organelles are discussed with emphasis on the importance of the chloroplast and mitochondrion to the nucleus retrograde signaling in acclimatory and stress response.