Alien Macroalgal Rearrangement in the Soft Substrata of the Venice Lagoon (Italy): Impacts, Threats, Time and Future Trends

Non-native species are a concern for aquatic environments both for the ecosystem biodiversity and from the economical point of view. The Venice Lagoon is a Mediterranean hotspot of alien introductions and macroalgae are probably the most represented systematic category. For this reason, alien macroalgal distribution and variation were monitored in late spring-autumn surveys, carried out in 2011, 2014, 2018 and 2021 in the soft bottoms of the entire lagoon (87 common stations). Overall, 21 taxa were recorded; three of them (i.e., Acanthosiphonia echinata, Caulacanthus okamurae, Osmundea oederi) are well-established recent introductions for the lagoon, which has increased the total number of non-native species to 33. Ulva australis, previously reported as Ulva laetevirens, is the most abundant species and it is replacing Ulva rigida, especially in the less eutrophic areas. The invasive Gracilariopsis vermiculophylla, an engineering species colonizing the eutrophic choked areas especially in the central lagoon, is instead decreasing. Other abundant established taxa are now dominant components of the lagoon biomass, whereas many others are rare or have small sizes that make their biomass negligible. Overall, these species do not represent serious threats to the environment, but they rather increase biodiversity, with some of them having positive effects on ecosystem services

Comparative genome analysis and genome-guided physiological analysis of Roseobacter litoralis

<p>Abstract</p> <p>Background</p> <p><it>Roseobacter litoralis </it>OCh149, the type species of the genus, and <it>Roseobacter denitrificans </it>OCh114 were the first described organisms of the <it>Roseobacter </it>clade, an ecologically important group of marine bacteria. Both species were isolated from seaweed and are able to perform aerobic anoxygenic photosynthesis.</p> <p>Results</p> <p>The genome of <it>R. litoralis </it>OCh149 contains one circular chromosome of 4,505,211 bp and three plasmids of 93,578 bp (pRLO149_94), 83,129 bp (pRLO149_83) and 63,532 bp (pRLO149_63). Of the 4537 genes predicted for <it>R. litoralis</it>, 1122 (24.7%) are not present in the genome of <it>R. denitrificans</it>. Many of the unique genes of <it>R. litoralis </it>are located in genomic islands and on plasmids. On pRLO149_83 several potential heavy metal resistance genes are encoded which are not present in the genome of <it>R. denitrificans</it>. The comparison of the heavy metal tolerance of the two organisms showed an increased zinc tolerance of <it>R. litoralis</it>. In contrast to <it>R. denitrificans</it>, the photosynthesis genes of <it>R. litoralis </it>are plasmid encoded. The activity of the photosynthetic apparatus was confirmed by respiration rate measurements, indicating a growth-phase dependent response to light. Comparative genomics with other members of the <it>Roseobacter </it>clade revealed several genomic regions that were only conserved in the two <it>Roseobacter </it>species. One of those regions encodes a variety of genes that might play a role in host association of the organisms. The catabolism of different carbon and nitrogen sources was predicted from the genome and combined with experimental data. In several cases, e.g. the degradation of some algal osmolytes and sugars, the genome-derived predictions of the metabolic pathways in <it>R. litoralis </it>differed from the phenotype.</p> <p>Conclusions</p> <p>The genomic differences between the two <it>Roseobacter </it>species are mainly due to lateral gene transfer and genomic rearrangements. Plasmid pRLO149_83 contains predominantly recently acquired genetic material whereas pRLO149_94 was probably translocated from the chromosome. Plasmid pRLO149_63 and one plasmid of <it>R. denitrifcans </it>(pTB2) seem to have a common ancestor and are important for cell envelope biosynthesis. Several new mechanisms of substrate degradation were indicated from the combination of experimental and genomic data. The photosynthetic activity of <it>R. litoralis </it>is probably regulated by nutrient availability.</p

Additional taxonomic coverage of the DUI (Doubly Uniparental Inheritance) in bivalves: evidence of sex-linked heteroplasmy in the razor clam Solen marginatus Pulteney, 1799, but not in the lagoon cockle Cerastoderma glaucum (Bruguière, 1789)

In animals, doubly uniparental inheritance (DUI) is a major exception to the common strict maternal inheritance of mitochondria. To date, DUI has only been found in many bivalve species, but its distribution is still unclear. Given the great species richness of the class, much effort is needed to further investigate the occurrence of DUI in unsampled species. A compelling evidence of DUI is generally the presence of a sex-linked heteroplasmy, where two divergent mitochondrial lineages are found: One is isolated from the male germline, and the other one is isolated from the female germline and, normally, from the soma of both sexes. In the present study, we investigated the sex-linked heteroplasmy in the razor clam Solen marginatus Pulteney, 1799 and in the lagoon cockle Cerastoderma glaucum (Bruguière, 1789) using two mitochondrial markers (cox1 and rrnL). We found evidence of DUI in the species S.&nbsp;marginatus, with a divergence up to 21% for the rrnL gene, but not in C.&nbsp;glaucum. Moreover, our phylogenetic reconstruction includes all the available data for heterodont species with sex-linked heteroplasmy and suggests multiple origins of DUI in this subclass, as well as the presence of DUI in other species of the genus Solen

C-phycoerythrin from Phormidium persicinum prevents acute kidney injury by attenuating oxidative and endoplasmic reticulum stress.

C-phycoerythrin (C-PE) is a phycobiliprotein that prevents oxidative stress and cell damage. The aim of this study was to evaluate whether C-PE also counteracts endoplasmic reticulum (ER) stress as a mechanism contributing to its nephroprotective activity. After C-PE was purified from Phormidium persicinum by using size exclusion chromatography, it was characterized by spectrometry and fluorometry. A mouse model of HgCl2-induced acute kidney injury (AKI) was used to assess the effect of C-PE treatment (at 25, 50, or 100 mg/kg of body weight) on oxidative stress, the redox environment, and renal damage. ER stress was examined with the same model and C-PE treatment at 100 mg/kg. C-PE diminished oxidative stress and cell damage in a dose-dependent manner by impeding the decrease in expression of nephrin and podocin normally caused by mercury intoxication. It reduced ER stress by preventing the activation of the inositol-requiring enzyme-1α (IRE1α) pathway and avoiding caspase-mediated cell death, while leaving the expression of protein kinase RNA-like ER kinase (PERK) and activating transcription factor 6α (ATF6α) pathways unmodified. Hence, C-PE exhibited a nephroprotective effect on HgCl2-induced AKI by reducing oxidative stress and ER stress

Biogenic iron-silver nanoparticles inhibit bacterial biofilm formation due to Ag+ release as determined by a novel phycoerythrin-based assay

Silver nanoparticles (Ag-NPs) can be considered as a cost-effective alternative to antibiotics. In the presence of Fe(III)-citrate and Ag+, Klebsiella oxytoca DSM 29614 produces biogenic Ag-NPs embedded in its peculiar exopolysaccharide (EPS). K. oxytoca DSM 29614 was cultivated in a defined growth medium–containing citrate (as sole carbon source) and supplemented with Ag+ and either low or high Fe(III) concentration. As inferred from elemental analysis, transmission and scanning electron microscopy, Fourier transform infrared spectrometry and dynamic light scattering, Ag-EPS NPs were produced in both conditions and contained also Fe. The production yield of high-Fe/Ag-EPS NPs was 12 times higher than the production yield of low-Fe/Ag-EPS NPs, confirming the stimulatory effect of iron. However, relative Ag content and Ag+ ion release were higher in low-Fe/Ag-EPS NPs than in high-Fe/Ag-EPS NPs, as revealed by emission-excitation spectra by luminescent spectrometry using a novel ad hoc established phycoerythrin fluorescence–based assay. Interestingly, high and low-Fe/Ag-EPS NPs showed different and growth medium–dependent minimal inhibitory concentrations against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442. In addition, low-Fe/Ag-EPS NPs exert inhibition of staphylococcal and pseudomonal biofilm formation, while high-Fe/Ag-EPS NPs inhibits staphylococcal biofilm formation only. Altogether, these results, highlighting the different capability of Ag+ release, support the idea that Fe/Ag-EPS NPs produced by K. oxytoca DSM 29614 can be considered as promising candidates in the development of specific antibacterial and anti-biofilm agents

Assessment of the European classification criteria for Sjogren&apos;s syndrome in a series of clinically defined cases: Results of a prospective multicentre study

Objective-To assess the recently proposed preliminary criteria for the classification of Sjogren’s syndrome (SS) in a multicentre European study of a new series of clinically defined cases. Methods-The criteria included six items: I = ocular symptoms; II = oral symptoms; III = evidence of keratoconjunctivitis sicca; IV = focal sialoadenitis by minor salivary gland biopsy; V = instrumental evidence of salivary gland involvement; VI = presence of autoantibodies. Each centre was asked to provide five patients with primary SS, dive with secondary SS, five with connective tissue diseases (CTD) but without SS, and five controls (patients with ocular or oral features that may simulate SS). The preliminary six item classification criteria set was applied to both the SS patients and the non-SS controls, and the performance of the criteria in terms of sensitivity and specificity was tested. Results-The criteria set was tested on a total of 278 cases (157 SS patients and 121 non-SS controls) collected from 16 centres in 10 countries. At least four of the six items in the criteria set (Limiting item VI to the presence of Ro(SS-A) or La(SS-B) antibodies) were present in 79 of 81 patients initially classified as having primary SS (sensitivity 97.5%), but in only seven of 121 non-SS controls (specificity 94.2%). When the presence of item I or II plus any two of items III-V of the criteria set was considered as indicative of secondary SS, 97.3% (71 of 73) of the patients initially defined as having this disorder and 91.8% (45 of 49) of the control patients with CTD without SS were correctly classified. Conclusion-This prospective study confirmed the high validity and reliability of the classification criteria for SS recently proposed by the European Community Study Group

Exploring Protein Conformational Diversity

The native state of proteins is composed of conformers in dynamical equilibrium. In this chapter, different issues related to conformational diversity are explored using a curated and experimentally based database called CoDNaS (Conformational Diversity in the Native State). This database is a collection of redundant structures for the same sequence. CoDNaS estimates the degree of conformational diversity using different global and local structural similarity measures. It allows the user to explore how structural differences among conformers change as a function of several structural features providing further biological information. This chapter explores the measurement of conformational diversity and its relationship with sequence divergence. Also, it discusses how proteins with high conformational diversity could affect homology modeling techniques.Fil: Monzon, Alexander Miguel. Universidad Nacional de Quilmes; ArgentinaFil: Fornasari, Maria Silvina. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zea, Diego Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Instituto Leloir; ArgentinaFil: Parisi, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; Argentin