Limits to crystallization pressure

Crystallization pressure drives deformation and damage in monuments, buildings, and the Earth’s crust. Even though the phenomenon has been known for 170 years, there is no agreement between theoretical calculations of the maximum attainable pressure and experimentally measured pressures. We have therefore developed a novel experimental technique to image the nanoconfined crystallization process while controlling the pressure and applied it to calcite. The results show that displacement by crystallization pressure is arrested at pressures well below the thermodynamic limit. We use existing molecular dynamics simulations and atomic force microscopy data to construct a robust model of the disjoining pressure in this system and thereby calculate the absolute distance between the surfaces. On the basis of the high-resolution experiments and modeling, we formulate a novel mechanism for the transition between damage and adhesion by crystallization that may find application in Earth and materials sciences and in conservation of cultural heritage

Additive Contributions of Two Manganese-Cored Superoxide Dismutases (MnSODs) to Antioxidation, UV Tolerance and Virulence of Beauveria bassiana

The biocontrol potential of entomopathogenic fungi against arthropod pests depends on not only their virulence to target pests but tolerance to outdoor high temperature and solar UV irradiation. Two Beauveria bassiana superoxide dismutases (SODs), BbSod2 and BbSod3, were characterized as cytosolic and mitochondrial manganese-cored isoenzymes (MnSODs) dominating the total SOD activity of the fungal entomopathogen under normal growth conditions. To probe their effects on the biocontrol potential of B. bassiana, ΔBbSod2, ΔBbSod3, and three hairpin RNA-interfered (RNAi) mutants with the transcripts of both BbSod2 and BbSod3 being suppressed by 91–97% were constructed and assayed for various phenotypic parameters in conjunction with ΔBbSod2/BbSod2, ΔBbSod3/BbSod3 and wild-type (control strains). In normal cultures, the knockout and RNAi mutants showed significant phenotypic alterations, including delayed sporulation, reduced conidial yields, and impaired conidial quality, but little change in colony morphology. Their mycelia or conidia became much more sensitive to menadione or H2O2-induced oxidative stress but had little change in sensitivity to the hyperosmolarity of NaCl and the high temperature of 45°C. Accompanied with the decreased antioxidative capability, conidial tolerances to UV-A and UV-B irradiations were reduced by 16.8% and 45.4% for ΔBbSod2, 18.7% and 44.7% for ΔBbSod3, and ∼33.7% and ∼63.8% for the RNAi mutants, respectively. Their median lethal times (LT50s) against Myzus persicae apterae, which were topically inoculated under a standardized spray, were delayed by 18.8%, 14.5% and 37.1%, respectively. Remarkably, the effects of cytosolic BbSod2 and mitochondrial BbSod3 on the phenotypic parameters important for the fungal bioncontrol potential were additive, well in accordance with the decreased SOD activities and the increased superoxide levels in the knockout and RNAi mutants. Our findings highlight for the first time that the two MnSODs co-contribute to the biocontrol potential of B. bassiana by mediating cellular antioxidative response

Reliability of FRL (Food Related Lifestyles) instrument in Polish cultural environment

Polski dorobek naukowy związany z badaniem zwyczajów i preferencji żywieniowych jest obszerny i zróżnicowany, a postępująca globalizacja powoduje coraz większe zainteresowanie międzykulturowymi analizami porównawczymi. W celu uzyskania wiarygodnych wyników takich porównań konieczne jest stosowanie zestandaryzowanych narzędzi, walidowanych międzykulturowo. Jednym z takich narzędzi jest FRL (Food Related Lifestyles) – narzędzie do badania preferencji zwyczajów i preferencji żywieniowych, zaprojektowane w celu dokonywania porównań pomiędzy różnymi kulturami czy krajami. Większość krajów europejskich została przebadana za pomocą FRL. Dowiedziono, że narzędzie jest wystarczająco odporne na różnice kulturowe i może być stosowane do badań porównawczych. Celem niniejszej pracy było sprawdzenie, czy narzędzie FRL jest rzetelną skalą pomiarową, która może być zastosowana w polskim środowisku kulturowym. Celem dodatkowym było sprawdzenie, czy sposób zbierania danych (wywiad osobisty i ankieta on-line) ma wpływ na rzetelność badania. Zastosowano dwie metody zbierania danych (wywiad osobisty i ankieta on-line) W przypadku wywiadu osobistego zastosowano schemat dwustopniowego doboru warstwowego. Jednostką doboru pierwszego stopnia było miejsce zamieszkania (województwo), jednostką doboru drugiego stopnia była liczba gospodarstw domowych. Ankieta on-line była dostępna bez ograniczeń i mogły ją wypełniać wszystkie zainteresowane osoby. Uzyskano odpowiedzi od 948 osób z terenu wszystkich województw w Polsce oraz ze wszystkich grup demograficznych. Rzetelność została oceniona za pomocą współczynnika Alpha Cronbacha zgodnie z metodą zaproponowaną przez Grunerta i wsp. W wyniku analizy stwierdzono, że w przypadku konstruktów dotyczących motywów zakupowych oraz sposobów przygotowywania posiłków rzetelność skali jest stosunkowo mała, jednak rzetelność narzędzia FRL dla Polski oraz jego przydatność do porównań międzykulturowych została potwierdzona.The Polish scientific achievements linked with habits and food preferences surveys are wide-ranging and varied, and the progressing globalization causes the interest in cross-cultural comparative analyzes to more and more increase. In order to obtain reliable results of such comparisons, it is necessary to apply standardized, cross-culturally validated tools. One such tool is FRL (Food Related Lifestyles), an instrument used in research studies on dietary habits and preferences and designed, specifically, to make comparisons among different cultures or countries. The majority of European countries were surveyed using the FRL instrument. It was proved that the FRL instrument is capable of sufficiently withstanding cultural differences and can be applied in comparative studies. The objective of this research study was to verify whether or not the FRL instrument is an accurate measuring scale and can be utilized in the Polish cultural environment. An additional objective was to check whether or not the method of collecting data (personal interview and on-line survey) impact the reliability of the FRL instrument. Two data collection methods were applied (personal interview and on-line interview). In the case of personal interview, a two-stage stratified sampling scheme was applied. The place of residence (region) was a first-stage sampling unit (region), and the number of households was a second-stage sampling unit. The on-line questionnaire was freely available and all interested persons could fill it in. 948 respondents from all provinces in Poland and in all demographic groups provided their responses. The reliability was assessed using a Cronbach’s alpha index pursuant to the methodology as proposed by Grunert at al. Based on the analysis results, it was found that in the case of constructs relating to buying motives and methods for preparing meals, the accuracy of measuring scale was relatively low; however, it was confirmed that the FRL instrument was reliable with regard to Poland and suitable for cross-cultural comparisons

SMC complexes and topoisomerase II work together so that sister chromatids can work apart

The pairing of sister chromatids in interphase facilitates error-free homologous recombination (HR). Sister chromatids are held together by cohesin, one of three Structural Maintenance of Chromosomes (SMC) complexes. In mitosis, chromosome condensation is controlled by another SMC complex, condensin, and the type II topoisomerase (Top2). In prophase, cohesin is stripped from chromosome arms, but remains at centromeres until anaphase, whereupon it is removed via proteolytic cleavage. The third SMC complex, Smc5/6, is generally described as a regulator of HR-mediated DNA repair. However, cohesin and condensin are also required for DNA repair, and HR genes are not essential for cell viability, but the SMC complexes are. Smc5/6 null mutants die in mitosis, and in fission yeast, Smc5/6 hypomorphs show lethal mitoses following genotoxic stress, or when combined with a Top2 mutant, top2-191. We found these mitotic defects are due to retention of cohesin on chromosome arms. We also show that Top2 functions in the cohesin cycle, and accumulating data suggests this is not related to its decatenation activity. Thus the SMC complexes and Top2 functionally interact, and any DNA repair function ascribed to Smc5/6 is likely a reflection of a more fundamental role in the regulation of chromosome structure