scholarly journals Dispersal patterns of meiospores shape population spatial structure of saxicolous lichens

2017 ◽  
Vol 49 (4) ◽  
pp. 397-413 ◽  
Author(s):  
M. MORANDO ◽  
S. E. FAVERO-LONGO ◽  
M. CARRER ◽  
E. MATTEUCCI ◽  
J. NASCIMBENE ◽  
...  

AbstractRelationships between reproductive strategies and population spatial structure have often been suggested for lichens, but there is a lack of supporting aerobiological data. For the first time, this study couples aerobiological investigations on meiospore dispersal byCaloplaca crenulatella(Nyl.) H. Olivier andRhizocarpon geographicum(L.) DC. with analysis of local spatial patterns of thalli of both species. During a two-year monitoring period carried out on the walls of a medieval castle in NW Italy, a total of 169 polar diblastic spores, 20% of which were morphologically attributable toC. crenulatella, was detected in the mycoareosol, while muriform spores ofR. geographicumwere never found. Laboratory experiments confirmed that different dispersal patterns characterize the two species, the meiospores ofR. geographicumbeing poorly discharged and only recovered at a short distance from thalli, whereas those ofC. crenulatellawere more abundantly discharged, suspended and better dispersed by a moderate air flow. This difference was reflected on the castle walls by the random spatial pattern ofC. crenulatella, whileR. geographicumshowed a clustered distribution. Different discharge rates and take-off limitations, possibly related to size differences between the spores, are not sufficient to explain the different colonization patterns and dynamics of the two species. Additional intrinsic and extrinsic factors are likely to drive their dispersal and establishment success. Nevertheless, information on the relationships between different dispersal patterns of the species and the local spatial structure of their populations might help to predict the recovery potential of lichen species exposed to habitat loss or disturbance, or encrusting monument surfaces.

Author(s):  
Mehdi Alidokht ◽  
Samaneh Yazdani ◽  
Esmaeil Hadavandi ◽  
Saeed Chehreh Chelgani

AbstractTri-flo cyclone, as a dense-medium separation device, is one of the most typical environmentally friendly industrial techniques in the coal washery plants. Surprisingly, no detailed investigation has been conducted to explore the effectiveness of tri-flo cyclone operating parameters on their representative metallurgical responses (yield and recovery). To fill this gap, this work for the first time in the coal processing sector is going to introduce a type of advanced intelligent method (boosted-neural network “BNN”) which is able to linearly and nonlinearly assess multivariable correlations among all variables, rank them based on their effectiveness and model their produced responses. These assessments and modeling were considered a new concept called “Conscious Laboratory (CL)”. CL can markedly decrease the number of laboratory experiments, reduce cost, save time, remove scaling up risks, expand maintaining processes, and significantly improve our knowledge about the modeled system. In this study, a robust monitoring database from the Tabas coal plant was prepared to cover various conditions for building a CL for coal tri-flo separators. Well-known machine learning methods, random forest, and support vector regression were developed to validate BNN outcomes. The comparisons indicated the accuracy and strength of BNN over the examined traditional modeling methods. In a sentence, generating a novel BNN within the CL concept can apply in various energy and coal processing areas, fill gaps in our knowledge about possible interactions, and open a new window for plants' fully automotive process.


2016 ◽  
Vol 3 (1) ◽  
pp. 53
Author(s):  
Giovanni Pasini ◽  
Alessandro Garassino

<em>Ethusa</em> sp. (Decapoda, Brachyura, Ethusidae) from Valduggia (Vercelli, Piedmont, NW Italy) is here reported for the first time from the Pliocene of Italy. This new finding enlarges our knowledge on the distribution and stratigraphic range of this genus in the paleo- Mediterranean basin.


1991 ◽  
Vol 123 (3) ◽  
pp. 501-558 ◽  
Author(s):  
Ian M. Smith

AbstractMorphological, life history, and distributional data are presented for North American species of the subgenus Stygomomonia (sensu stricto) Szalay, 1943. Adults of the seven previously recognized species are redescribed, and deutonymphs of five of these species are described for the first time. Two species, S. (s.s.) neomexicana Cook and S. (s.s.) occidentalis Cook are substantially revised on the basis of an examination of the types and extensive series of newly collected specimens. Three new species are described, S. (s.s.) californiensis on the basis of deutonymphs and adults, and S. (s.s.) imamurai and S. (s.s.) cooki on the basis of adults. A new diagnosis of the subgenus is proposed and discussed, the relationships of the various species are discussed, and a key to deutonymphs and adults of North American species is presented. New distributional data are presented for all species, and dispersal patterns from Pleistocene refugia are discussed.


Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1951 ◽  
Author(s):  
Thi-Bach-Le Nguyen ◽  
Olivier Delalande ◽  
Isabelle Rouaud ◽  
Solenn Ferron ◽  
Laura Chaillot ◽  
...  

Two compounds (1) and (2) containing tert-butylphenol groups were, for the first time, produced during the culture of Paenibacillus odorifer, a bacterial strain associated with the crustose lichen, Rhizocarpon geographicum. Their entire structures were identified by one-dimensional (1D) and two-dimensional (2D) NMR and high-resolution electrospray ionisation mass spectrometry (HRESIMS) spectroscopic analyses. Among them, Compound 1 exhibited significant cytotoxicity against B16 murine melanoma and HaCaT human keratinocyte cell lines with micromolar half maximal inhibitory concentration (IC50) values. Furthermore, after supplementation studies, a putative biosynthesis pathway was proposed for Compound 1 throughout a bioconversion by this bacterial strain of butylated hydroxyanisole (BHA), an antioxidant polymer additive.


Spatial models of the β - structures of protein molecules, forming layers of amino acids, in principle, of unlimited length for both antiparallel and parallel conformation have been constructed. It is shown that the simplified flat Pauling models do not reflect the spatial structure of these layers. Using the recently developed theory of higher-dimensional polytopic prismahedrons, models of the volumetric filling of space with amino acid molecules are constructed. The constructed models for the first time mathematically describe the native structures of globular proteins.


Fisheries ◽  
2020 ◽  
Vol 2020 (1) ◽  
pp. 66-70
Author(s):  
Yuri Simakov ◽  
Dmitry Nikiforov-Nikishin ◽  
Larisa Bychkova ◽  
Nadegda Lyubovskaya

The results of laboratory experiments on nitroglycerine toxicity detected by histological and cytological indices are presented, using Danio rerio as a case study. For the first time, there are shown the changes in liver and kidneys, both at tissular and cellular levels, induced by administered concentrations of nitroglycerine. The results obtained appear to be important for water bodies’ preservation and elaboration of MPC standards. The intake of nitroglycerine into water bodies is due, mainly, to discharge from pharmaceutical enterprises, demolition works, and outflow from explosives storehouses. Fish turned out to be sensitive to nitroglycerine as indicated by histological and hematological indices. Maximum permissible concentration, MPC, for Danio rerio is determined to be equal to 0.5 mg/l.


2020 ◽  
Vol 90 (7) ◽  
pp. 687-700
Author(s):  
Jamie L. Hizzett ◽  
Esther J. Sumner ◽  
Matthieu J.B. Cartigny ◽  
Michael A. Clare

ABSTRACT Seafloor sediment density flows are the primary mechanism for transporting sediment to the deep sea. These flows are important because they pose a hazard to seafloor infrastructure and deposit the largest sediment accumulations on Earth. The cohesive sediment content of a flow (i.e., clay) is an important control on its rheological state (e.g., turbulent or laminar); however, how clay becomes incorporated into a flow is poorly understood. One mechanism is by the abrasion of (clay-rich) mud clasts. Such clasts are common in deep-water deposits, often thought to have traveled over large (more than tens of kilometers) distances. These long travel distances are at odds with previous experimental work that suggests that mud clasts should disintegrate rapidly through abrasion. To address this apparent contradiction, we conduct laboratory experiments using a counter rotating annular flume to simulate clast transport in sediment density flows. We find that as clay clasts roll along a sandy floor, surficial armoring develops and reduces clast abrasion and thus enhances travel distance. For the first time we show armoring to be a process of renewal and replenishment, rather than forming a permanent layer. As armoring reduces the rate of clast abrasion, it delays the release of clay into the parent flow, which can therefore delay flow transformation from turbidity current to debris flow. We conclude that armored mud clasts can form only within a sandy turbidity current; hence where armored clasts are found in debrite deposits, the parent flow must have undergone flow transformation farther up slope.


mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Juan de Dios Caballero ◽  
Rafael Vida ◽  
Marta Cobo ◽  
Luis Máiz ◽  
Lucrecia Suárez ◽  
...  

ABSTRACT Cystic fibrosis (CF) lung microbiota composition has recently been redefined by the application of next-generation sequencing (NGS) tools, identifying, among others, previously undescribed anaerobic and uncultivable bacteria. In the present study, we monitored the fluctuations of this ecosystem in 15 CF patients during a 1-year follow-up period, describing for the first time, as far as we know, the presence of predator bacteria in the CF lung microbiome. In addition, a new computational model was developed to ascertain the hypothetical ecological repercussions of a prey-predator interaction in CF lung microbial communities. Fifteen adult CF patients, stratified according to their pulmonary function into mild (n = 5), moderate (n = 9), and severe (n = 1) disease, were recruited at the CF unit of the Ramón y Cajal University Hospital (Madrid, Spain). Each patient contributed three or four induced sputum samples during a 1-year follow-up period. Lung microbiota composition was determined by both cultivation and NGS techniques and was compared with the patients’ clinical variables. Results revealed a particular microbiota composition for each patient that was maintained during the study period, although some fluctuations were detected without any clinical correlation. For the first time, Bdellovibrio and Vampirovibrio predator bacteria were shown in CF lung microbiota and reduced-genome bacterial parasites of the phylum Parcubacteria were also consistently detected. The newly designed computational model allows us to hypothesize that inoculation of predators into the pulmonary microbiome might contribute to the control of chronic colonization by CF pathogens in early colonization stages. IMPORTANCE The application of NGS to sequential samples of CF patients demonstrated the complexity of the organisms present in the lung (156 species) and the constancy of basic individual colonization patterns, although some differences between samples from the same patient were observed, probably related to sampling bias. Bdellovibrio and Vampirovibrio predator bacteria were found for the first time by NGS as part of the CF lung microbiota, although their ecological significance needs to be clarified. The newly designed computational model allows us to hypothesize that inoculation of predators into the lung microbiome can eradicate CF pathogens in early stages of the process. Our data strongly suggest that lower respiratory microbiome fluctuations are not necessarily related to the patient’s clinical status. IMPORTANCE The application of NGS to sequential samples of CF patients demonstrated the complexity of the organisms present in the lung (156 species) and the constancy of basic individual colonization patterns, although some differences between samples from the same patient were observed, probably related to sampling bias. Bdellovibrio and Vampirovibrio predator bacteria were found for the first time by NGS as part of the CF lung microbiota, although their ecological significance needs to be clarified. The newly designed computational model allows us to hypothesize that inoculation of predators into the lung microbiome can eradicate CF pathogens in early stages of the process. Our data strongly suggest that lower respiratory microbiome fluctuations are not necessarily related to the patient’s clinical status.


1989 ◽  
Vol 1989 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Poojitha D. Yapa ◽  
Tamara Chowdhury

ABSTRACT A new set of equations is presented for describing oil spreading under ice in calm waters. These equations consider the constant discharge mode, constant volume mode, and termination of spreading due to a balance of forces. Therefore, a complete description of the spreading phenomena from the time of initial spill to termination of spreading is presented. The equations are derived based on a simplified form of Navier-Stokes equations. Laboratory experiments were conducted using ice covers of different roughnesses, oils of different viscosities, and varying discharge rates. The theory agrees closely with the experimental data.


2021 ◽  
Author(s):  
Szymon Zaczek ◽  
Agnieszka Dybala-Defratyka

Background Prenylated flavin mononucleotide (prFMN) is a recently discovered, heavily modified flavin compound. It is the only known cofactor that enables enzymatic 1,3-dipolar cycloaddition reactions. It is produced by enzymes from UbiX family, from flavin mononucleotide and either dimethylallyl mono- or diphosphate. prFMN biosynthesis is currently reported to be initiated by a protonation of the substrate by Glu140. Methods Computational chemistry methods are applied herein - mostly different flavors of molecular dynamics MD, such as Constant pH MD, hybrid Quantum-Mechanical / Molecular Mechanical MD, and classical MD. Results Glu140 competes for a single proton with Lys129 but it is the latter that adopted a protonated state throughout most of the simulation time. Lys129 plays a key role in the positioning of the DMAP’s phosphate group within the PaUbiX active site. DMAP’s breakdown into a phosphate and a prenyl group can be decoupled from the protona-tion of the DMAP’s phosphate group. Conclusions The role of Lys129 in functioning of PaUbiX is reported for the first time. The severity of interactions between Glu140, Lys129, and DMAP’s phosphate group enables an unusual decoupling of phosphate’s protonation from DMAP’s breakdown. Those findings are most likely conserved throughout the UbiX family to the structural re-semblence of active sites of those proteins. Significance Mechanistic insights into a crucial biochemical process, biosynthesis of prFMN, are provided. This study, alt-hough purely computational, extends and perfectly complements the knowledge obtained in classical laboratory experiments.


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