scholarly journals Las especies de Splachnaceae (Bryophyta) de Tierra del Fuego, Argentina: las esporas y sus modos de dispersión

2021 ◽  
Vol 9 (2) ◽  
pp. 254-264
Author(s):  
Rosana Solan ◽  
M. Raquel Piñeiro

The Splachnaceae family is a bryological component of the temperate forests of Nothofagus in the Fuegian region of Argentina. It is represented by the Tayloria genera with three species, T. dubyi (endemic), T. magellanica, T. mirabilis, and Tetraplodon, with a single specie Tetraplodon fuegianus. They grow on organic substrates of animal origin and are the only family among mosses in the area in which entomochory is observed (i.e. dispersion of spores through insects). From herbarium material, the taxonomic features of gametophytes and sporophytes which allow species to be identified are described. Spores were studied with OM and SEM. Dispersal vectors for Tayloria mirabilis and morfo-ecological adaptations associated with entomochory were observed and analyzed. Mosses are differentiated from their leaves and the morphology and color of the sporophyte capsules. The spores, similar in the studied species, are dispersed in sticky masses, they are spheroidal, monoletes, 8-13 μm of diameter with a pitted-reticulate ornamentation. The dispersing agents mostly correspond to the order Diptera. The Splachnaceae family has developed adaptive strategies in relation to substrate (coprophilous gametophytes), in striking and showy sporophytes morphologies and in a particular dispersal mode of the spores by insects. All these morpho-ecological adaptations contribute to an effective action of the dispersing agents in the muscinal biocenosis.

2018 ◽  
Vol 85 (2) ◽  
Author(s):  
Daniele Bruno ◽  
Marco Bonelli ◽  
Francesca De Filippis ◽  
Ilaria Di Lelio ◽  
Gianluca Tettamanti ◽  
...  

ABSTRACT The larva of the black soldier fly (Hermetia illucens) has emerged as an efficient system for the bioconversion of organic waste. Although many research efforts are devoted to the optimization of rearing conditions to increase the yield of the bioconversion process, microbiological aspects related to this insect are still neglected. Here, we describe the microbiota of the midgut of H. illucens larvae, showing the effect of different diets and midgut regions in shaping microbial load and diversity. The bacterial communities residing in the three parts of the midgut, characterized by remarkable changes in luminal pH values, differed in terms of bacterial numbers and microbiota composition. The microbiota of the anterior part of the midgut showed the highest diversity, which gradually decreased along the midgut, whereas bacterial load had an opposite trend, being maximal in the posterior region. The results also showed that the influence of the microbial content of ingested food was limited to the anterior part of the midgut, and that the feeding activity of H. illucens larvae did not significantly affect the microbiota of the substrate. Moreover, a high protein content compared to other macronutrients in the feeding substrate seemed to favor midgut dysbiosis. The overall data indicate the importance of taking into account the presence of different midgut structural and functional domains, as well as the substrate microbiota, in any further study that aims at clarifying microbiological aspects concerning H. illucens larval midgut. IMPORTANCE The demand for food of animal origin is expected to increase by 2050. Since traditional protein sources for monogastric diets are failing to meet the increasing demand for additional feed production, there is an urgent need to find alternative protein sources. The larvae of Hermetia illucens emerge as efficient converters of low-quality biomass into nutritionally valuable proteins. Many studies have been performed to optimize H. illucens mass rearing on a number of organic substrates and to quantitatively and qualitatively maximize the biomass yield. On the contrary, although the insect microbiota can be fundamental for bioconversion processes and its characterization is mandatory also for safety aspects, this topic is largely overlooked. Here, we provide an in-depth study of the microbiota of H. illucens larval midgut, taking into account pivotal aspects, such as the midgut spatial and functional regionalization, as well as microbiota and nutrient composition of the feeding substrate.


2018 ◽  
Author(s):  
Rachel M. Germain ◽  
Natalie T. Jones ◽  
Tess N. Grainger

AbstractSpecies interact with the physical world in complex ways, and life history strategies might cause species to differ in how they experience connectedness of the same landscape. As a consequence, dispersal limitation might be present but not captured by distance-based measures of connectivity. To test these ideas, we surveyed plant communities that associate with serpentine soils but differ in dispersal mode (gravity, animal, or wind), and used satellite imagery to quantify forms of landscape connectivity associated with each dispersal mode. Our data yielded two key insights: First, dispersal limitation appeared to be absent using a conventional distance-based measure of connectivity, but emerged after considering forms of landscape connectivity relevant to each dispersal mode. Second, the landscape variables that emerged as important to each dispersal mode were generally consistent with our predictions based on putative dispersal vectors, and included interactive effects that allude to the altered efficacy of animal dispersal in invaded landscapes. Our results have broad implications for understanding how ecological communities reorganize as landscapes are fragmented, patches are lost, and the function of dispersal life histories is altered.


2018 ◽  
Vol 187 (1) ◽  
pp. 119-128
Author(s):  
Krystyna Skurjat

The text addresses the growing interest in praxeology as the theory of effective action in the form that has been given to this field mainly by Tadeusz Kotarbinski. The transformation of the social order requires the application of technical recommendations that improve all good work, and praxeology determines the canons of such efficiency such precisely. Praxeology also enforces the use of ethnical norms and references to value systems because they determine adaptive strategies of individuals and social groups, and thus influence the organizational culture of a company.


2020 ◽  
Vol 10 (16) ◽  
pp. 5451 ◽  
Author(s):  
Zuzana Kisová ◽  
Matej Planý ◽  
Jelena Pavlović ◽  
Mária Bučková ◽  
Andrea Puškárová ◽  
...  

A historical crypt offers us a particular view of the conditions of some buried materials (in this case textiles) and the various biogenic phenomena to which they were subjected over the centuries. In addition, significant knowledge can come by studying the DNA of buried objects which allows the recognition of materials, but also to reveal some practice of the funeral ceremony. In this study, the deteriorating microbial communities colonizing various funeral textile items were identified and characterized using microscopic observation, cultivation, polymerase chain reaction (PCR) and sequencing, hydrolytic tests; and culture-independent analysis (high-throughput sequencing, MinION platform). Different PCR assays and consequent sequencing of amplicons were employed to recognize the animal origin of bodice reinforcements and the type of plant used to embellish the young girl. The analysis of ancient DNA (aDNA from animal and plant) was also completed by the application of high-throughput sequencing through Illumina platform. The combination of all these techniques permitted the identification of a complex microbiota composed by dangerous degradative microorganisms able to hydrolyze various organic substrates such as fibroin, keratin, and cellulose. Bacteria responsible for metal corrosion and bio-mineralization, and entomopathogenic and phytopathogenic fungi. The analysis of aDNA identified the animal component used in bodice manufacturing, the plant utilized as ornament and probably the season of this fatal event.


Author(s):  
Douglas L. Dorset

A variety of linear chain materials exist as polydisperse systems which are difficultly purified. The stability of continuous binary solid solutions assume that the Gibbs free energy of the solution is lower than that of either crystal component, a condition which includes such factors as relative molecular sizes and shapes and perhaps the symmetry of the pure component crystal structures.Although extensive studies of n-alkane miscibility have been carried out via powder X-ray diffraction of bulk samples we have begun to examine binary systems as single crystals, taking advantage of the well-known enhanced scattering cross section of matter for electrons and also the favorable projection of a paraffin crystal structure posited by epitaxial crystallization of such samples on organic substrates such as benzoic acid.


2020 ◽  
Vol 4 (4) ◽  
pp. 365-381
Author(s):  
Ny Anjara Fifi Ravelomanantsoa ◽  
Sarah Guth ◽  
Angelo Andrianiaina ◽  
Santino Andry ◽  
Anecia Gentles ◽  
...  

Seven zoonoses — human infections of animal origin — have emerged from the Coronaviridae family in the past century, including three viruses responsible for significant human mortality (SARS-CoV, MERS-CoV, and SARS-CoV-2) in the past twenty years alone. These three viruses, in addition to two older CoV zoonoses (HCoV-229E and HCoV-NL63) are believed to be originally derived from wild bat reservoir species. We review the molecular biology of the bat-derived Alpha- and Betacoronavirus genera, highlighting features that contribute to their potential for cross-species emergence, including the use of well-conserved mammalian host cell machinery for cell entry and a unique capacity for adaptation to novel host environments after host switching. The adaptive capacity of coronaviruses largely results from their large genomes, which reduce the risk of deleterious mutational errors and facilitate range-expanding recombination events by offering heightened redundancy in essential genetic material. Large CoV genomes are made possible by the unique proofreading capacity encoded for their RNA-dependent polymerase. We find that bat-borne SARS-related coronaviruses in the subgenus Sarbecovirus, the source clade for SARS-CoV and SARS-CoV-2, present a particularly poignant pandemic threat, due to the extraordinary viral genetic diversity represented among several sympatric species of their horseshoe bat hosts. To date, Sarbecovirus surveillance has been almost entirely restricted to China. More vigorous field research efforts tracking the circulation of Sarbecoviruses specifically and Betacoronaviruses more generally is needed across a broader global range if we are to avoid future repeats of the COVID-19 pandemic.


2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 25-29 ◽  
Author(s):  
Guangwen Tang

Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.


1990 ◽  
Vol 4 (6) ◽  
pp. 262
Author(s):  
P.R. Wyman

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