scholarly journals Reconstructing the ecology of a Jurassic pseudoplanktonic megaraft colony

2019 ◽  
Author(s):  
Aaron W. Hunter ◽  
David Casenove ◽  
Emily G. Mitchell ◽  
Celia Mayers
Keyword(s):  
Moisture Diffusion ◽  
Oceanic Islands ◽  
Diffusion Models ◽  
Deep Time ◽  
Cast Doubt ◽  
Commercial Logging ◽  
Mode Of Life ◽  
First Time

AbstractPseudoplanktonic crinoid megaraft colonies are an enigma of the Jurassic. They are among the largest in-situ invertebrate accumulations ever to exist in the Phanerozoic fossil record. These megaraft colonies and are thought to have developed as floating filter-feeding communities due to an exceptionally rich relatively predator free oceanic niche, high in the water column enabling them to reach high densities on these log rafts. However, this pseudoplanktonic hypothesis has never actually been quantitatively tested and some researchers have cast doubt that this mode of life was even possible. The ecological structure of the crinoid colony is resolved using spatial point process techniques and its longevity using moisture diffusion models. Using spatial analysis we found that the crinoids would have trailed preferentially positioned at the back of migrating structures in the regions of least resistance, consistent with a floating, not benthic ecology. Additionally, we found using a series of moisture diffusion models at different log densities and sizes that ecosystem collapse did not take place solely due to colonies becoming overladen as previously assumed. We have found that these crinoid colonies studied could have existed for greater than 10 years, even up to 20 years exceeding the life expectancy of modern documented megaraft systems with implications for the role of modern raft communities in the biotic colonisation of oceanic islands and intercontinental dispersal of marine and terrestrial species.Significance statementTransoceanic rafting is the principle mechanism for the biotic colonisation of oceanic island ecosystems. However, no historic records exist of how long such biotic systems lasted. Here, we use a deep-time example from the Early Jurassic to test the viability of these pseudoplanktonic systems, resolving for the first time whether these systems were truly free floating planktonic and viable for long enough to allow its inhabitants to grow to maturity. Using spatial methods we show that these colonies have a comparable structure to modern marine pesudoplankton on maritime structures, whilst the application of methods normally used in commercial logging is used to demonstrate the viability of the system which was capable of lasting up to 20 years.

scholarly journals Reconstructing the ecology of a Jurassic pseudoplanktonic raft colony

2020 ◽  
Vol 7 (7) ◽  
pp. 200142
Author(s):  
Aaron W. Hunter ◽  
David Casenove ◽  
Celia Mayers ◽  
Emily G. Mitchell
Keyword(s):  
Spatial Analysis ◽  
Life Expectancy ◽  
Moisture Diffusion ◽  
Oceanic Islands ◽  
Diffusion Models ◽  
Spatial Point ◽  
Floating System ◽  
Mode Of Life ◽  
Ecosystem Collapse

Pseudoplanktonic crinoid raft colonies are an enigma of the Jurassic. These raft colonies are thought to have developed as floating filter-feeding communities due to an exceptionally rich oceanic niche, high in the water column enabling them to reach large densities on these log rafts. However, this pseudoplanktonic hypothesis has not been quantitatively tested, and there remains some doubt that this mode of life was possible. The ecological structure of the crinoid colony is resolved using spatial point process analyses and the duration estimates of the floating system until sinking using moisture diffusion models. Using spatial analysis, we found that the crinoids would have trailed preferentially positioned at the back of the floating log in the regions of least resistance, consistent with a floating, not benthic ecology. Additionally, we found using a series of moisture diffusion models at different log densities and sizes that ecosystem collapse did not take place solely due to colonies becoming overladen as previously assumed. Our analyses have found that these crinoid colonies studied could have existed for more than 10 years, even up to 20 years, exceeding the life expectancy of modern documented raft systems with possible implications for the role of modern raft communities in the biotic colonization of oceanic islands and intercontinental dispersal of marine and terrestrial species.

scholarly journals Boosting the in situ encapsulation of proteins with MIL-100(Fe): the role of strong Lewis acid centers

2021 ◽  
Author(s):  
Jesús Cases ◽  
Mónica Giménez-Marqués
Keyword(s):  
General Strategy ◽  
Triggered Release ◽  
Strong Lewis Acid ◽  
Metal Organic ◽  
Broad Variety ◽  
Acid Centers ◽  
First Time ◽  
Surface Nature

Encapsulation of biomolecules using Metal-Organic Frameworks (MOFs) to form stable biocomposites has been demonstrated a valuable strategy for their preservation and controlled release, which has been however restricted to specific electrostatic surface conditions. We present a general in situ strategy that promotes the spontaneous MOF growth onto a broad variety of proteins, for the first time, regardless of their surface nature. We demonstrate that MOFs based on cations exhibiting considerable inherent acidity such as MIL-100(Fe) enable biomolecule encapsulation, including alkaline proteins previously inaccesible by the welldeveloped in situ encapsulation with azolate-based MOFs. In particular, MIL-100(Fe) scaffold permits effective encapsulation of proteins with very distinct surface nature, retaining their activity and allowing triggered release under biocompatible conditions. This general strategy will enable an ample use of biomolecules in desired biolotechnological applications.

scholarly journals Glycodelin mRNA is expressed in the genital tract of male and female rats (Rattus norvegicus)

1999 ◽  
Vol 23 (1) ◽  
pp. 57-66 ◽  
Author(s):  
C Keil ◽  
B Husen ◽  
J Giebel ◽  
G Rune ◽  
R Walther
Keyword(s):  
Epithelial Cells ◽  
Reproductive Tract ◽  
In Situ Hybridisation ◽  
Physiological Role ◽  
Reproductive Organs ◽  
Female Rats ◽  
Male And Female Rats ◽  
First Time

In the present study we demonstrate for the first time the expression of glycodelin mRNA in the female and male genital tracts of rats using non-radioactive in situ hybridisation. Glycodelin fragment 1 (+41 to +141) shares 100% homology with the human gene sequence. In the ovary, glycodelin mRNA was restricted to granulosa cells. In the uterus, glycodelin mRNA was expressed in all epithelial cells of the endometrium. In the male reproductive tract, glycodelin mRNA was distributed in all epithelial cells of the epididymis, the prostate and the seminal vesicle. However, in the testis, glycodelin mRNA was predominantly found in spermatogonia and in spermatocytes of the seminiferous epithelium. The expression in several reproductive organs of rats offers an excellent tool to study further the physiological role of glycodelin, which is so far thought to act as an immunosuppressive factor.

An in situ photoelectroreduction approach to fabricate Bi/BiOCl heterostructure photocathodes: understanding the role of Bi metal for solar water splitting

2017 ◽  
Vol 5 (10) ◽  
pp. 4894-4903 ◽  
Author(s):  
Weiqiang Fan ◽  
Chunfa Li ◽  
Hongye Bai ◽  
Yanyan Zhao ◽  
Bifu Luo ◽  
...  
Keyword(s):  
Water Splitting ◽  
Solar Water ◽  
Solar Water Splitting ◽  
Novel Method ◽  
First Time ◽  
Bi Nanoparticles ◽  
Pec Water Splitting

This paper presents for the first time a novel method of in situ depositing plasmonic Bi nanoparticles on BiOCl nanosheets (Bi/BiOCl) for PEC water splitting.

Arteries of the antebrachium and manus of the tokay (Gekko gecko) (Reptilia: Gekkonidae)

1981 ◽  
Vol 59 (4) ◽  
pp. 573-582 ◽  
Author(s):  
Anthony P. Russell
Keyword(s):  
Circulatory System ◽  
Arterial System ◽  
Functional Interpretation ◽  
Gekko Gecko ◽  
Low Viscosity ◽  
Adhesive Pads ◽  
The Subject ◽  
First Time

The role of the circulatory system in the functioning of the subdigital adhesive pads of geckoes has been the subject of much discussion. However, the morphology and configuration of the blood system in the foot has remained poorly understood, rendering functional interpretation of the blood sinuses simplistic. Here the major arterial vessels of the manus are described for the first time and a discussion of their geometry is presented. Due to the paucity of information concerning the arterial system of the appendages of lizards a description of the major vessels of the antebrachium is also given.The data presented are based on the study of material injected with low-viscosity silicone rubber and then cleared so that vessels may be studied in situ. The data are pertinent to subsequent discussions of the microvasculature of the subdigital lamellae and of reconsiderations of their structure and form.

scholarly journals Are global hotspots of endemic richness shaped by plate tectonics?

2017 ◽  
Author(s):  
Pellissier Loïc ◽  
Christian Heine ◽  
Camille Albouy
Keyword(s):  
Plate Tectonics ◽  
Large Fraction ◽  
Spatial Models ◽  
Future Research ◽  
Deep Time ◽  
Current Location ◽  
Lithospheric Plates ◽  
Taxonomic Groups

AbstractSingular regions of the globe harbour a disproportionally large fraction of extant biodiversity. Spatial biodiversity gradients are frequently associated to extant ecological conditions using statistical models, but more rarely to paleo-environmental conditions, especially beyond the Quaternary. On one hand the role of plate tectonics in shaping the extant diversity of lineages is supported by numerous phylogenetic and fossil evidences, and on the other hand the spatial variation of biodiversity across the globe is rarely associated to geodynamic variables. In this study, we propose that plate tectonics explain the current location of hotspots of endemic richness across the globe. As an illustration, we used paleogeographies in a model, which quantifies through time and for each cell the potential dispersal across disconnected habitat patches. Rare events of dispersal across dynamic straits of unsuitable habitats allows species colonisation and that a subsequent absence of gene flow could lead to in-situ speciation. We evaluated whether this process could pinpoint the locations of hotspots of endemic richness computed from the ranges of 181,603 species across 14 taxonomic groups. The significant congruence between the regions highlighted by the model and the endemic richness provides evidences of the contribution of plate tectonics in shaping global biodiversity gradients. Places with high tectonic complexity, predominantly located at the confluence of major lithospheric plates such as the Mediterranean basin, Central America, Madagascar and South East Asia likely provided favourable circumstances for allopatric speciation and the emergence of new species across straits. While our illustration supports the role of plate tectonics, accounting for deep time geological events in spatial models of extant biodiversity is not straightforward. Future research should develop quantitative spatial models of biodiversity including the dynamic of ancient habitats.

scholarly journals Ooids forming in situ within microbial mats (Kiritimati atoll, central Pacific)

PalZ ◽  
2021 ◽  
Author(s):  
Pablo Suarez-Gonzalez ◽  
Joachim Reitner
Keyword(s):  
Organic Matter ◽  
Microbial Communities ◽  
Microbial Mats ◽  
Formation Processes ◽  
Central Pacific ◽  
Environmental Processes ◽  
Definition Of ◽  
First Time

AbstractOoids (subspherical particles with a laminated cortex growing around a nucleus) are ubiquitous in the geological record since the Archean and have been widely studied for more than two centuries. However, various questions about them remain open, particularly about the role of microbial communities and organic matter in their formation and development. Although ooids typically occur rolling around in agitated waters, here, we describe for the first time aragonite ooids forming statically within microbial mats from hypersaline ponds of Kiritimati (Kiribati, central Pacific). Subspherical particles had been previously observed in these mats and classified as spherulites, but these particles grow around autochthonous micritic nuclei, and many of them have laminated cortices, with alternating radial fibrous laminae and micritic laminae. Thus, they are compatible with the definition of the term ‘ooid’ and are in fact very similar to many modern and fossil examples. Kiritimati ooids are more abundant and developed in some ponds and in some particular layers of the microbial mats, which leads to the discussion and interpretation of their formation processes as product of mat evolution, through a combination of organic and environmental factors. Radial fibrous laminae are formed during periods of increased supersaturation, either by metabolic or environmental processes. Micritic laminae are formed in closer association with the mat exopolymer (EPS) matrix, probably during periods of lower supersaturation and/or stronger EPS degradation. Therefore, this study represents a step forward in the understanding of ooid development as influenced by microbial communities, providing a useful analogue for explaining similar fossil ooids.

scholarly journals Oomycete small RNAs invade the plant RNA-induced silencing complex for virulence

2019 ◽  
Author(s):  
Florian Dunker ◽  
Adriana Trutzenberg ◽  
Jan Samuel Rothenpieler ◽  
Sarah Kuhn ◽  
Reinhard Pröls ◽  
...  
Keyword(s):  
Small Rnas ◽  
Rna Silencing ◽  
Fungal Pathogens ◽  
Gene Knockout ◽  
Enhanced Resistance ◽  
Race Pcr ◽  
Hyaloperonospora Arabidopsidis ◽  
First Time

AbstractFungal small RNAs (sRNAs) hijack the plant RNA silencing pathway to manipulate host gene expression, named cross-kingdom RNA interference (ckRNAi). It is currently unknown how conserved and significant ckRNAi is for microbial virulence. Here, we found for the first time that sRNAs of a pathogen representing the oomycete kingdom invade the host plant’s Argonaute (AGO)/RNA-induced silencing complex. To demonstrate the functionality of the plant-invading oomycete Hyaloperonospora arabidopsidis sRNAs (HpasRNAs), we designed a novel CRISPR endoribonuclease Csy4/GUS repressor reporter to visualize in situ pathogen-induced target suppression in Arabidopsis thaliana host plant. By using 5’ RACE-PCR we demonstrated HpasRNAs-directed cleavage of plant mRNAs. The significant role of HpasRNAs together with AtAGO1 in virulence was demonstrated by plant atago1 mutants and by transgenic Arabidopsis expressing a target mimic to block HpasRNAs, that both exhibited enhanced resistance. Individual HpasRNA plant targets contributed to host immunity, as Arabidopsis gene knockout or HpasRNA-resistant gene versions exhibited quantitative enhanced or reduced susceptibility, respectively. Together with previous reports, we found that ckRNAi is conserved among oomycete and fungal pathogens.

Roland and Crusade Imagery in an English Royal Chapel: early thirteenth-century wall paintings in Claverley church, Shropshire

2012 ◽  
Vol 92 ◽  
pp. 129-168 ◽  
Author(s):  
Christopher Barrett
Keyword(s):  
Thirteenth Century ◽  
Early Years ◽  
Historical Background ◽  
The North ◽  
The Status ◽  
North Wall ◽  
First Time ◽  
The Church

A frieze of mounted knights, over 15m long, dominates the nave of the church of All Saints, Claverley, Shropshire. It is part of an extensive mural scheme from the first quarter of the thirteenth century. For the first time the status of Claverley as a Royal Chapel is recognized and the royal and crusading character of the imagery is discussed. The emperors Constantine and Heraclius are identified as part of the Exaltation of the Holy Cross subject on the north wall, and the Holy Cross is suggested as the unifying theme, pre-dating the Florentine mural cycle by Agnolo Gaddi by some 170 years. Claverley is also shown to have the only medieval mural of Roland, hero of the Chanson de Roland, to survive in situ. The historical background of the early years of Henry iii is examined and the possible role of Ranulf de Blondeville, earl of Chester, in commissioning the frieze is considered.

scholarly journals Fungal Associates of Soft Scale Insects (Coccomorpha: Coccidae)

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1922
Author(s):  
Teresa Szklarzewicz ◽  
Katarzyna Michalik ◽  
Beata Grzywacz ◽  
Małgorzata Kalandyk-Kołodziejczyk ◽  
Anna Michalik
Keyword(s):  
Fat Body ◽  
Scale Insects ◽  
Fungal Symbiont ◽  
Symbiotic Interaction ◽  
Soft Scale ◽  
Symbiont Transmission ◽  
Fungal Associates ◽  
First Time

Ophiocordyceps fungi are commonly known as virulent, specialized entomopathogens; however, recent studies indicate that fungi belonging to the Ophiocordycypitaceae family may also reside in symbiotic interaction with their host insect. In this paper, we demonstrate that Ophiocordyceps fungi may be obligatory symbionts of sap-sucking hemipterans. We investigated the symbiotic systems of eight Polish species of scale insects of Coccidae family: Parthenolecanium corni, Parthenolecanium fletcheri, Parthenolecanium pomeranicum, Psilococcus ruber, Sphaerolecanium prunasti, Eriopeltis festucae, Lecanopsis formicarum and Eulecanium tiliae. Our histological, ultrastructural and molecular analyses showed that all these species host fungal symbionts in the fat body cells. Analyses of ITS2 and Beta-tubulin gene sequences, as well as fluorescence in situ hybridization, confirmed that they should all be classified to the genus Ophiocordyceps. The essential role of the fungal symbionts observed in the biology of the soft scale insects examined was confirmed by their transovarial transmission between generations. In this paper, the consecutive stages of fungal symbiont transmission were analyzed under TEM for the first time.

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