47 research outputs found

    Comparative evaluation of antimutagenic and antimitotic effects of Morchella esculenta extracts and protocatechuic acid

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    Morchella esculenta (L.) Pers. methanolic extracts, obtained from fruiting bodies growing wild in Serbia and Portugal, were screened for their antimutagenic properties and compared to protocatechuic acid, previously identified in both species. Salmonella typhimurium TA100 reversion assay was used for the antimutagenic properties. Methanolic extracts expressed important antimutagenic potency towards S. typhimurium, which was documented by index of antimutagenicity (I). A sample from Serbia expressed slightly higher antimutagenic properties with an inhibition rate of 58.7%. A sample from Portugal gave an inhibition rate of 51.7%. Protocatechuic acid had an inhibition rate I of his(+) revertants of 72.4%. Cell viability in the presence of extracts was also documented. M. esculenta samples from Serbia and Portugal possessed novel biological potential for the studied species, as well as its phenolic compound - protocatechuic acid, identified in both samples. Genotoxic effect, regarding mitotic index and chromosomal aberration score, was also assessed by using the Allium cepa L. assay. Protocatechuic acid showed the most significant decrease in mitotic index, as well as decrease in chromosomal aberration score

    Equatorial Layered Deposits in Arabia Terra, Mars: Facies and process variability

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    We investigated the equatorial layered deposits (ELDs) of Arabia Terra, Mars, in Firsoff crater and on the adjacent plateau. We produced a detailed geological map that included a survey of the relative stratigraphic relations and crater count dating. We reconstructed the geometry of the layered deposits and inferred some compositional constraints. ELDs drape and onlap the plateau materials of late Noachian age, while they are unconformably covered by early and middle Amazonian units. ELDs show the presence of polyhydrated sulfates. The bulge morphology of the Firsoff crater ELDs appears to be largely depositional. The ELDs on the plateau display a sheet-drape geometry. ELDs show different characteristics between the crater and the plateau occurrences. In the crater they consist of mounds made of breccia sometimes displaying an apical pit laterally grading into a light-toned layered unit disrupted in a meter-scale polygonal pattern. These units are commonly associated with fissure ridges suggestive of subsurface sources. We interpret the ELDs inside the craters as spring deposits, originated by fl uid upwelling through the pathways likely provided by the fractures related to the crater formations, and debouching at the surface through the fi ssure ridges and the mounds, leading to evaporite precipitation. On the plateau, ELDs consist of rare mounds, fl atlying deposits, and cross-bedded dune fields. We interpret these mounds as possible smaller spring deposits, the fl at-lying deposits as playa deposits, and the cross-bedded dune fi elds as aeolian deposits. Groundwater fluctuations appear to be the major factor controlling ELD deposition

    COSPAR Sample Safety Assessment Framework (SSAF).

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    The Committee on Space Research (COSPAR) Sample Safety Assessment Framework (SSAF) has been developed by a COSPAR appointed Working Group. The objective of the sample safety assessment would be to evaluate whether samples returned from Mars could be harmful for Earth's systems (e.g., environment, biosphere, geochemical cycles). During the Working Group's deliberations, it became clear that a comprehensive assessment to predict the effects of introducing life in new environments or ecologies is difficult and practically impossible, even for terrestrial life and certainly more so for unknown extraterrestrial life. To manage expectations, the scope of the SSAF was adjusted to evaluate only whether the presence of martian life can be excluded in samples returned from Mars. If the presence of martian life cannot be excluded, a Hold & Critical Review must be established to evaluate the risk management measures and decide on the next steps. The SSAF starts from a positive hypothesis (there is martian life in the samples), which is complementary to the null-hypothesis (there is no martian life in the samples) typically used for science. Testing the positive hypothesis includes four elements: (1) Bayesian statistics, (2) subsampling strategy, (3) test sequence, and (4) decision criteria. The test sequence capability covers self-replicating and non-self-replicating biology and biologically active molecules. Most of the investigations associated with the SSAF would need to be carried out within biological containment. The SSAF is described in sufficient detail to support planning activities for a Sample Receiving Facility (SRF) and for preparing science announcements, while at the same time acknowledging that further work is required before a detailed Sample Safety Assessment Protocol (SSAP) can be developed. The three major open issues to be addressed to optimize and implement the SSAF are (1) setting a value for the level of assurance to effectively exclude the presence of martian life in the samples, (2) carrying out an analogue test program, and (3) acquiring relevant contamination knowledge from all Mars Sample Return (MSR) flight and ground elements. Although the SSAF was developed specifically for assessing samples from Mars in the context of the currently planned NASA-ESA MSR Campaign, this framework and the basic safety approach are applicable to any other Mars sample return mission concept, with minor adjustments in the execution part related to the specific nature of the samples to be returned. The SSAF is also considered a sound basis for other COSPAR Planetary Protection Category V, restricted Earth return missions beyond Mars. It is anticipated that the SSAF will be subject to future review by the various MSR stakeholders

    COSPAR Sample Safety Assessment Framework (SSAF)

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    The Committee on Space Research (COSPAR) Sample Safety Assessment Framework (SSAF) has been developed by a COSPAR appointed Working Group. The objective of the sample safety assessment would be to evaluate whether samples returned from Mars could be harmful for Earth's systems (e.g., environment, biosphere, geochemical cycles). During the Working Group's deliberations, it became clear that a comprehensive assessment to predict the effects of introducing life in new environments or ecologies is difficult and practically impossible, even for terrestrial life and certainly more so for unknown extraterrestrial life. To manage expectations, the scope of the SSAF was adjusted to evaluate only whether the presence of martian life can be excluded in samples returned from Mars. If the presence of martian life cannot be excluded, a Hold & Critical Review must be established to evaluate the risk management measures and decide on the next steps. The SSAF starts from a positive hypothesis (there is martian life in the samples), which is complementary to the null-hypothesis (there is no martian life in the samples) typically used for science. Testing the positive hypothesis includes four elements: (1) Bayesian statistics, (2) subsampling strategy, (3) test sequence, and (4) decision criteria. The test sequence capability covers self-replicating and non-self-replicating biology and biologically active molecules. Most of the investigations associated with the SSAF would need to be carried out within biological containment. The SSAF is described in sufficient detail to support planning activities for a Sample Receiving Facility (SRF) and for preparing science announcements, while at the same time acknowledging that further work is required before a detailed Sample Safety Assessment Protocol (SSAP) can be developed. The three major open issues to be addressed to optimize and implement the SSAF are (1) setting a value for the level of assurance to effectively exclude the presence of martian life in the samples, (2) carrying out an analogue test program, and (3) acquiring relevant contamination knowledge from all Mars Sample Return (MSR) flight and ground elements. Although the SSAF was developed specifically for assessing samples from Mars in the context of the currently planned NASA-ESA MSR Campaign, this framework and the basic safety approach are applicable to any other Mars sample return mission concept, with minor adjustments in the execution part related to the specific nature of the samples to be returned. The SSAF is also considered a sound basis for other COSPAR Planetary Protection Category V, restricted Earth return missions beyond Mars. It is anticipated that the SSAF will be subject to future review by the various MSR stakeholders

    Revealing the astragalin mode of anticandidal action.

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    Due to limited arsenal of systemically available antifungal agents, infections caused by Candida albicans are difficult to treat and the emergence of drug-resistant strains present a major challenge to the clinicians worldwide. Hence further exploration of potential novel and effective antifungal drugs is required. In this study we have explored the potential of a flavonoid, astragalin, in controlling the growth of C. albicans, in both planktonic and biofilm forms by microdilution method; and in regulating the morphological switch between yeast and hyphal growth. Astragalin ability to interfere with membrane integrity, ergosterol synthesis and its role in the regulation of genes encoding for efflux pumps has been addressed. In our study, astragalin treatment produced good antimicrobial and significant antibiofilm activity. Anticandidal activity of astragalin was not related to ERG11 downregulation, neither to direct binding to CYP51 enzyme nor was linked to membrane ergosterol assembly. Instead, astragalin treatment resulted in reduced expression of CDR1 and also affected cell membrane integrity without causing cytotoxic effect on human gingival fibroblast cells. Considering that astragalin-mediated decreased expression of efflux pumps increases the concentration of antifungal drug inside the fungal cells, a combinatorial treatment with this agent could be explored as a novel therapeutic option for candidiasis

    EFFECT OF METEOROLOGICAL CONDITIONS ON THE PRODUCTION OF NS SOYA BEAN SEED

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    The perspective of our society cannot be imagined without the quality production and marketing of seeds in the country and abroad. On average, seed soya bean was annually planted on area of 7,151.8 ha in the period 2002-2007. Area under NS soya bean seed showed an annual trend rate of growth (9.21% with certain oscillations). In the research period, soya bean seed yield was 2.29 t ha-1 with a highly stable growth rate of 2.66%, while NS soya bean seed production in Serbia was 15,993 t with an annual growth rate of 12.59% with certain oscillations. Permanent growing trend of soya bean production is a result of increased area and yield. The increase of production was also affected by weather conditions. Such production volume fully meets domestic needs, while significant amount of seed still remains for export

    Astrobiology, the Emergence of Life, and Planetary Exploration

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    Astrobiology brings together all the scientific specialties focused on deciphering origin of life, its nature and evolution, and possible distri-bution in the universe. Exceptionally rapid progress has been made over the past four decades; including new insights into how life began on Earth, the continuous extension of boundaries within which we can find life thriv-ing in the most hostile terrestrial environments, the evidence of common presence of liquid water in the universe, a controversial discovery of past life in a Martian meteorite, and the existence of Earth-like planets orbiting starts of Milky Way. Although, the only planet we know of that host life in our solar system, and perhaps in the universe is, still, Earth, scientists con-tinue to search for clues that could reveal the origin and distribution of life elsewhere

    Equatorial Layered Deposits in Arabia Terra, Mars: Stratigraphy and Process Variability

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    The equatorial layered deposits of Arabia Terra are investigated to understand their genesis and the controls on their evolution. We interpret the deposits found within the craters as having been formed by spring deposition based on the large-scale geometry, the presence of morphologies consistent with fluid expulsion, the composition, and the sedimentary structures. Outside of the craters, we found evidence of dune forms and cross-stratification suggestive of aeolian activity, possibly associated with playa deposition. Groundwater fluctuations are suggested as the control on deposition
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