170,305 research outputs found
Deep-sea benthic ecosystems waste nothing and recycle everything, even viruses
No full textViruses are the most abundant biological entities of the global ocean and have a pervasive role in marine ecosystems because, being a major cause of mortality, they module the functioning of food webs, and biogeochemical cycling. This role is due not only to their ability to infect and lyse marine organisms but also to the decomposition of their particles (viral decay). The organic matter of viral origin, indeed, can be recycled by benthic organisms thus representing an additional important food source for their metabolism, especially in deep-sea sediments, characterized by very low availability of trophic resources. This short note will present an overview of the available information on viral decay in deep-sea benthic ecosystems
Digital Options for the Rehabilitation of the Atrophic Edentulous Maxilla
No full textObjective:
The aim of this study was to describe fully digital workflows for the Prosthetically Guided Reconstructive Surgery (PGRS) of edentulous patients affected by atrophic maxilla.
Methods:
The preoperative provisional removable full-denture was used as starting point to determine aesthetics parameters, occlusion of the final prosthetic rehabilitation as well as the respective maxillary implant positions using conventional softwares for the diagnosis of available bone and for the design of the full-arch prosthesis. The regenerative option (bone augmentation using customized titanium mesh), or the long implant option (navigated zygomatic implants) were both digitally projected depending on the patient needs. After implants healing, two sets of digital impressions were acquired: set #1 was the digital impression of implant positions; set #2 was the digitalization of the provisional full denture together with the impression of the rear side. The two sets were digitally combined into a single file. The metal framework of the final prosthesis was designed and manufactured using digital hybrid manufacturing technology and clinically evaluated with Sheffield test and radiographs; at the same time a resin prototype was produced for clinical try-in of aesthetic and functional parameters.
Results:
Aesthetic parameters and the occlusion of the provisional removable full-denture were digitally transferred to the provisional and definitive full-arch fixed prosthesis. The digital models were 3D-printed in occlusion to finalize in three steps the full-arch prosthesis.
Conclusions:
The workflows of PGRS allowed realizing the full process of the prosthetic and surgical rehabilitation of edentulous patients with atrophic maxilla using a complete digital CAD-CAM technology.
1: Cordaro L, Amadé DS, Cordaro M. Clinical results of alveolar ridge augmentation with mandibular block bone grafts in partially edentulous patients prior to implant placement. Clin Oral Implants Res. 2002 Feb;13(1):103-11. PubMed PMID: 12005140.
2: Pellegrino G, Lizio G, Corinaldesi G, Marchetti C. Titanium Mesh Technique in Rehabilitation of Totally Edentulous Atrophic Maxillae: A Retrospective Case Series. J Periodontol. 2016 May;87(5):519-28. doi: 10.1902/jop.2016.150432. Epub 2016 Jan 12. PubMed PMID: 26759078.
3: Tuminelli FJ, Walter LR, Neugarten J, Bedrossian E. Immediate loading of zygomatic implants: A systematic review of implant survival, prosthesis survival and potential complications. Eur J Oral Implantol. 2017;10 Suppl 1:79-87. Review. PubMed PMID: 28944370.
4: Ciocca L, Lizio G, Baldissara P, Sambuco A, Scotti R, Corinaldesi G. Prosthetically CAD-CAM-Guided Bone Augmentation of Atrophic Jaws Using Customized Titanium Mesh: Preliminary Results of an Open Prospective Study. J Oral Implantol. 2018 Apr;44(2):131-137. doi: 10.1563/aaid-joi-D-17-00125. Epub 2018 Jan 5. PubMed PMID: 29303418.
5: Ciocca L, Ragazzini S, Fantini M, Corinaldesi G, Scotti R. Work flow for the prosthetic rehabilitation of atrophic patients with a minimal-intervention CAD/CAM approach. J Prosthet Dent. 2015 Jul;114(1):22-6. doi: 10.1016/j.prosdent.2014.11.014. Epub 2015 Apr 7. PubMed PMID: 25862269
Carotenoids from Marine Organisms: Biological Functions and Industrial Applications
No full textAs is the case for terrestrial organisms, carotenoids represent the most common group of pigments in marine environments. They are generally biosynthesized by all autotrophic marine organisms, such as bacteria and archaea, algae and fungi. Some heterotrophic organisms also contain carotenoids probably accumulated from food or partly modified through metabolic reactions. These natural pigments are divided into two chemical classes: carotenes (such as lycopene and α- and β-carotene) that are composed of hydrogen and carbon; xanthophylls (such as astaxanthin, fucoxanthin and lutein), which are constituted by hydrogen, carbon and oxygen. Carotenoids, as antioxidant compounds, assume a key role in the protection of cells. In fact, quenching of singlet oxygen, light capture and photosynthesis protection are the most relevant biological functions of carotenoids. The present review aims at describing (i) the biological functions of carotenoids and their benefits for human health, (ii) the most common carotenoids from marine organisms and (iii) carotenoids having large success in pharmaceutical, nutraceutical and cosmeceutical industries, highlighting the scientific progress in marine species cultivation for natural pigments production
From virus isolation to metagenome generation for investigating viral diversity in deep-sea sediments
No full textViruses, prokaryotes and biochemical composition of organic matter in different types of mucilage aggregates
No full textIt has been hypothesised that several microbial processes contribute to mucilage formation and transformation. However, to date, none of these mechanisms have been consistently tested using different types of mucilage. We investigated the biochemical composition and the microbial activities occurring in 9 different types of mucilage aggregates (macroflocs, stringers, cobwebs, ribbons, stringers/cobwebs clouds, big creamy surface layer, false bottoms and anoxic false bottoms) collected during summer 2000, 2002 and 2003 in the Adriatic Sea. Larger and aged aggregates, characterized by the accumulation of carbohydrate and a low lipid fraction, displayed significant biochemical differences when compared with younger aggregates. Prokaryote abundance, C production and extracellular enzymatic activities increased from small to medium-sized aggregates (corresponding approximately to mid life span) while they decreased in larger (and aged) aggregates. The highest prokaryotic C production and enzymatic activities were coupled with highest viral abundance. In mucilage displaying the highest viral abundance a reduced incorporation of enzymatically degraded C into prokaryote biomass was observed. This result suggests a potential involvement of viruses in the impairment of the microbial loop functioning in marine aggregates. Applying a multivariate analysis to the microbial variables, 3 stages of mucilage life span can be identified: (1) an early stage characterized by a large prokaryote colonization of the aggregate and DOM accumulation; (2) a mature stage characterized by a decreased capability of incorporating degraded C into prokaryote biomass and high viral abundance and (3) an aged stage characterized by the decrease in both viral and prokaryote abundance and prokaryote activity. These results provide new insights into the microbial ecology of marine aggregates and the processes influencing their life span
Extraction efficiency of different microplastic polymers from deep-sea sediments and their quantitative relevance
No full textAn increasing number of methods for extracting microplastic particles from marine sediments have been published but without evaluating the extraction efficiency. Furthermore, while most of the procedures developed have been applied to sandy sediments from shallow water habitats, specific and standardized procedures for deep-water sediments (> 200 meters deep) are limited. In this study, we describe a specific protocol for extracting microplastics (2- 1000 μm) from deep-sea sediments and for quantifying and identifying them. We also assessed its extraction efficiency, which resulted in a high recovery (on average ca. 60%, and up to 80%) particularly, for polyethylene, polypropylene, and polystyrene. This method can be applied to all fine-grained/muddy sediments and allows the extraction of even the smallest fraction of microplastics (<20 μm), which are expected to have the most severe effects on marine biodiversity and ecosystem functioning and ultimately also have implications for human health
Deep hypersaline anoxic basins as untapped reservoir of polyextremophilic prokaryotes of biotechnological interest
No full text
Metagenetic tools for the census of marine meiofaunal biodiversity: An overview
No full textAbstract
Marine organisms belonging to meiofauna (size range: 20–500 μm) are amongst the most abundant and highly diversified metazoans on Earth including 22 over 35 known animal Phyla and accounting formore than 2/3 of the abundance ofmetazoan organisms. In anymarine system,meiofauna play a key role in the functioning of the food webs and sustain important ecological processes. Estimates of meiofaunal biodiversity have been so far almost exclusively based on morphological analyses, but the very small size of these organisms and, in some cases, the insufficient morphological distinctive features limit considerably the census of the biodiversity of this component. Molecular approaches recently applied also to small invertebrates (including meiofauna) can offer a new momentum for the census of meiofaunal biodiversity. Here, we provide an overview on the application of metagenetic approaches based on the use of next generation sequencing platforms to study meiofaunal biodiversity, with a special focus on marine nematodes. Our overview shows that, although such approaches can represent a useful tool for the census of meiofaunal biodiversity, there are still different shortcomings and pitfalls that prevent their extensive use without the support of the classical taxonomic identification. Future investigations are needed to address these problems and to provide a goodmatch between the contrasting findings emerging from classical taxonomic and molecular/bioinformatic tools
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