Phylogenetic and biogeographic history of brook lampreys (Lampetra: Petromyzontidae) in the river basins of the Adriatic Sea based on DNA barcode data.

The Adriatic brook lamprey, Lampetra zanandreai Vladykov 1955, was described from northeastern Italy. Its distribution is thought to include left tributaries of the River Po and the river basins of the Adriatic Sea from the River Po to the River Isonzo/Soca in Italy, Switzerland and Slovenia. It also shows a geographically isolated distribution in the Potenza River on the Adriatic slope in Central Italy. Lampetra from the Neretva River system in Croatia and Bosnia and Herzegovina and the Moraca River system in Montenegro that were previously identified as L. zanandreai were recently described as a new species Lampetra soljani Tutman, Freyhof, Dulcic, Glamuzina & Geiger 2017 based on morphological data and a genetic distance between the two species of roughly 2.5% in the DNA barcoding gene cytochrome oxidase I (COI). Since DNA barcodes for L. zanandreai are only available for one population from the upper Po River in northwestern Italy, we generated additional COI nucleotide sequence data of this species from Switzerland, northeastern and central Italy comprising near topotypic material and obtained GenBank sequences of the species from Slovenia to better assess the evolutionary history of the two brook lamprey species in the river basins of the Adriatic Sea. Our data show a low sequence divergence of <1% between L. zanandreai from Switzerland, northeastern and central Italy and Slovenia and the Balkan species L. soljani. However, members of the population previously identified as 'L. zanandreai' from northwest Italy are genetically highly divergent from those of L. zanandreai and likely belong to an undescribed species, L. sp. 'upper Po'. The presence of a unique and highly divergent brook lamprey lineage in the upper Po River suggests that L. zanandreai and Lampetra sp. 'upper Po' may have evolved in separate paleo drainages during the formation of the modern Po Valley subsequent to marine inundations in the Pliocene.

Peruvian efforts to contain COVID-19 fail to protect vulnerable population groups.

Peru is arguably providing a robust governmental response in the initial stages of the COVID-19 outbreak, with early lockdown measures and the implementation of relatively ambitious economic safety nets to protect families and enterprises. Despite this initial optimism, structural deficiencies in the public health system, high informality in the labor market, the new wave of migrants from Venezuela and the extremely diverse cultural characteristics of many areas exacerbate the number of potentially highly vulnerable groups that may be left out of these safety nets unless additional efforts are enforced to improve social coverage. In this discussion we aim to identify some of these groups, highlighting the main challenges they face during the outbreak and proposing certain mitigation measures to balance the social policy response.

Intraoral scanners in dentistry: a review of the current literature.

BACKGROUND: Intraoral scanners (IOS) are devices for capturing direct optical impressions in dentistry. The purpose of this narrative review on the use of IOS was to: (1) identify the advantages/disadvantages of using optical impressions compared to conventional impressions; (2) investigate if optical impressions are as accurate as conventional impressions; (3) evaluate the differences between the IOS currently available commercially; (4) determine the current clinical applications/limitations in the use of IOS. METHODS: Electronic database searches were performed using specific keywords and MeSH terms. The searches were confined to full-text articles written in English and published in peer-reviewed journals between January 2007 and June 2017. RESULTS: One hundred thirty-two studies were included in the present review; among them, 20 were previous literature reviews, 78 were in vivo clinical studies (6 randomized controlled/crossover trials, 31 controlled/comparative studies; 24 cohort studies/case series; 17 case reports) and 34 were in vitro comparative studies. CONCLUSIONS: Optical impressions reduce patient discomfort; IOS are time-efficient and simplify clinical procedures for the dentist, eliminating plaster models and allowing better communication with the dental technician and with patients; however, with IOS, it can be difficult to detect deep margin lines in prepared teeth and/or in case of bleeding, there is a learning curve, and there are purchasing and managing costs. The current IOS are sufficiently accurate for capturing impressions for fabricating a whole series of prosthetic restorations (inlays/onlays, copings and frameworks, single crowns and fixed partial dentures) on both natural teeth and implants; in addition, they can be used for smile design, and to fabricate posts and cores, removable partial prostheses and obturators. The literature to date does not support the use of IOS in long-span restorations with natural teeth or implants. Finally, IOS can be integrated in implant dentistry for guided surgery and in orthodontics for fabricating aligners and custom-made devices.

New Evidences of Mitochondrial DNA Heteroplasmy by Putative Paternal Leakage between the Rock Partridge (Alectoris graeca) and the Chukar Partridge (Alectoris chukar).

The rock partridge, Alectoris graeca, is a polytypic species declining in Italy mostly due to anthropogenic causes, including the massive releases of the closely related allochthonous chukar partridge Alectoris chukar which produced the formation of hybrids. Molecular approaches are fundamental for the identification of evolutionary units in the perspective of conservation and management, and to correctly select individuals to be used in restocking campaigns. We analyzed a Cytochrome oxidase I (COI) fragment of contemporary and historical A. graeca and A. chukar samples, using duplicated analyses to confirm results and nuclear DNA microsatellites to exclude possible sample cross-contamination. In two contemporary specimens of A. graeca, collected from an anthropogenic hybrid zone, we found evidence of the presence of mtDNA heteroplasmy possibly associated to paternal leakage and suggesting hybridization with captive-bred exotic A. chukar. These results underline significant limitations in the reliability of mtDNA barcoding-based species identification and could have relevant evolutionary and ecological implications that should be accounted for when interpreting data aimed to support conservation actions.

Mother's Age and Hatching Phenology Strategy of Heterocypris incongruens (Crustacea: Ostracoda) in Unpredictable Environment.

We report experimental evidence of egg polyphenism in clonal lineages of Heterocypris incongruens from an ephemeral pond on a Mediterranean Island (Lampedusa, Italy). In controlled laboratory conditions, clonal females produced three different kinds of eggs: (i) resting and desiccation-resistant eggs, (ii) nonresting eggs that hatched gradually within 2 month hydroperiod, and (iii) nonresting delayed development eggs that hatched synchronously. Clonal females showed a diversified bet-hedging strategy to spread risk of reproduction in ponds with unpredictable hydroperiod. They adjusted proportion of different egg phenotypes in response to experimental temperature and photoperiod that are proxies for different hydroperiod unpredictability. The proportion of resting eggs is not affected by maternal age at deposition, but mother's age has a key role in defining the development time and the hatching phenology of nonresting eggs. Genetically identical eggs kept at the same controlled laboratory conditions showed a U-shaped distribution of development time. Development time variance decreased with mother's age at deposition. The resulting wedge-shaped relationship between development time and mother's age at deposition may be interpreted by considering mother's age as a proxy for the probability of drought onset. The older the mother, the shorter the latency to drought and the shorter is the time for nonresting eggs to hatch. Considering only the delayed development of eggs that hatch synchronously, development time is inversely related to the mother's age at deposition: this relationship generates the observed hatching peak.

Mitochondrial genome of Esox flaviae (Southern pike): announcement and comparison with other Esocidae.

Pikes are fish species belonging to order Esociformes, family Esocidae, genus Esox. Species of the genus Esox are common, large, and economically important for food and fishing activities. Recently, a new species, southern pike E. flaviae, was described for a well-studied area such as Italy, using also two mtDNA markers: cox1 and cytb. A scant number of remnant populations of the species persist in Italy, threatened by habitat loss and degradation and by competition and possible hybridization with E. lucius, massively and recurrently stocked to sustain angling pressure. The availability of new mtDNA markers will possibly contribute to the conservation of the species. Currently, whole mitogenome information for the genus is available only for E. lucius and for E. reichertii. The aim of the present paper is to report novel mitogenomic information for southern pike.

The evolutionary jigsaw puzzle of the surviving trout (Salmo trutta L. complex) diversity in the Italian region. A multilocus Bayesian approach.

Mediterranean trout populations display a diversity of phenotypes, representing a valuable model for the study of adaptation and a puzzling dilemma for taxonomists and biogeographers, which is further entangled by the widespread introgression of allochthonous genes. In this paper we analysed DNA polymorphism at multiple loci (sequence variation of the mitochondrial control region and eight nuclear fragments and length variation at eleven nuclear microsatellite loci) in representative samples of the autochthonous taxonomic diversity described in Italian trout populations (Salmo marmoratus, S. carpio, S. cenerinus, S. cettii and S. fibreni) and in samples from hatchery-originated strains of Atlantic S. trutta. We employed model-based clustering and Approximate Bayesian Computation in order to: (i) describe the phylogeographic structure of Italian autochthonous trout populations; (ii) evaluate a set of evolutionary/biogeographic models. The inclusion of hatchery-originated strains allowed to account for man-mediated allochthonous introgression in Italian populations. Our results (i) showed that the analysed sample consists of two main autochthonous evolutionary lineages, including the marble trout populations on one side ('marble' lineage) and the three peninsular populations of S. cettii, S. cenerinus and S. fibreni on the other side ('peninsular' lineage); (ii) indicated that S. carpio originated from a 'peninsular' population, with a possible, limited contribution from the 'marble' lineage; (iii) pointed out that the 'marble' lineage started diverging before the separation of the 'peninsular' lineage from Atlantic S. trutta; (iv) suggested that a model of divergence involving gene flow from the 'peninsular' population into the ancestral gene pool of 'marble' trout is most consistent with the genetic data; (v) provided evidence that the autochthonous trout gene pools in the Tyrrhenian and Adriatic basins of the Italian peninsula started diverging very recently (most likely after the last glacial maximum).

Defining conservation units in a stocking-induced genetic melting pot: unraveling native and multiple exotic genetic imprints of recent and historical secondary contact in Adriatic grayling.

The definition of conservation units is crucial for the sustainable management of endangered species, though particularly challenging when recent and past anthropogenic and natural gene flow might have played a role. The conservation of the European grayling, Thymallus thymallus, is particularly complex in its southern distribution area, where the Adriatic evolutionary lineage is endangered by a long history of anthropogenic disturbance, intensive stocking and potentially widespread genetic introgression. We provide mtDNA sequence and microsatellite data of 683 grayling from 30 sites of Adriatic as well as Danubian and Atlantic origin. We apply Bayesian clustering and Approximate Bayesian Computation (ABC) to detect microgeographic population structure and to infer the demographic history of the Adriatic populations, to define appropriate conservation units. Varying frequencies of indigenous genetic signatures of the Adriatic grayling were revealed, spanning from marginal genetic introgression to the collapse of native gene pools. Genetic introgression involved multiple exotic source populations of Danubian and Atlantic origin, thus evidencing the negative impact of few decades of stocking. Within the Adige River system, a contact zone of western Adriatic and eastern Danubian populations was detected, with ABC analyses suggesting a historical anthropogenic origin of eastern Adige populations, most likely founded by medieval translocations. Substantial river-specific population substructure within the Adriatic grayling Evolutionary Significant Unit points to the definition of different conservation units. We finally propose a catalog of management measures, including the legal prohibition of stocking exotic grayling and the use of molecular markers in supportive- and captive-breeding programs.

Frequent recombination shapes the epidemic population structure of Planktothrix (Cyanoprokaryota) in Italian subalpine lakes.

The planktonic genus Planktothrix, as other cyanobacteria, shows signals of both homologous and nonhomologous recombination. However, the frequency of recombination and its effect on Planktothrix population structuring is unknown. We isolated 290 Planktothrix strains from seven neighboring lakes in the subalpine Italian region and analyzed these using multilocus sequence typing. Four of six loci analyzed were polymorphic, resulting in 20 distinct multilocus genotypes. Association indices among alleles at different loci were suggestive of an "epidemic population structure," resulting from an explosive (and temporary) dominance of one genotype against a panmictic background. ClonalFrame analyses supported this view by detecting: (i) three major clades affected by three distinct recombination events, (ii) a recombination rate about equal to the mutation rate, and (iii) the fact that recombination had an impact on introducing molecular diversity more than double the mutation rate. Furthermore, analysis of molecular variance over an annual cycle in three of seven lakes revealed that both local clonal expansion and recombination processes affected among-lake diversity. Our observations suggest that recombination affects microevolution of Planktothrix and that an epidemic structure can emerge in populations of this genus.

Recombination Signals In The rpoC1 Gene Indicate Gene-Flow Between Planktothrix (Cyanoprokaryota) Species.

The delineation of species boundaries in the potentially harmful cyanobacterium Planktothrix Anagnostidis et Komárek 1988 is particularly tangled. Genetic recombination has been invoked to explain the occurrence of overlapping biological traits among recognized species. Although horizontal gene transfer is shown as a driver of diversification in this genus, clear evidence for homologous recombination at the single gene level is still lacking. Several Planktothrix strains (n = 244) sampled in eight fresh water lakes in north Italy were characterized by sequencing the rpoC1 gene, a molecular marker previously proposed to discriminate between species. Six haplotypes were detected, four of which are newly described. A relevant number of rpoC1 sequences (n = 54) showed evidence of homologous recombination. By comparing the sequences produced in the work presented here to those available on GenBank for the genus, multiple recombination events were tracked between haplotypes associated to P. rubescens, P. suspensa and P. agardhii, the latter being a species not found in our survey. Recombination signals were in form of (i) a vast mosaic structure present in the alignment of rpoC1 haplotypes, (ii) multiple and statistically significant paths in the split decomposition network connecting these haplotypes and (iii) many individual crossing-over events detected by means of recombination detection tests. Data suggest that the molecular evolution of the rpoC1 gene in the genus Planktothrix appears as strongly influenced by homologous recombination. In addition, rpoC1 diversity effectively tracks recombinational processes among species in the complex made up by P. rubescens, P. agardhii and P. suspensa, which are not isolated in terms of gene-flow.

Phylogenetic relationships of coexisting Heterocypris (Crustacea, Ostracoda) lineages with different reproductive modes from Lampedusa Island (Italy).

Coexisting bisexual and unisexual populations of individuals belonging to the genus Heterocypris are found in ephemeral freshwater ponds on the island of Lampedusa (Pelagie Islands, Italy). Different reproductive modes were associated with a peculiar morphological trait: a lamella hyalina on the posterior margin of the left valve was observed in amphimictic females, a feature missing in apomictic females. In order to clarify the phylogenetic relationships among taxa with different morphological traits and reproductive modes, we used four polymorphic enzyme loci (GPI, ICD2, MPI and PGM) and mitochondrial DNA 16S ribosomal sequences. We identified three main evolutionary units that showed a combination of morphological and reproductive characteristics: (1) amphimictic females of H. barbara with a lamella hyalina, according to the typical feature of the species, and apomictic females of H. barbara without lamella that are sympatric in one temporary pond; (2) apomictic females of H. incongruens without a lamella, as typical of the species; (3) apomictic females without a lamella, living in sympatry with H. barbara, but characterised by a high genetic diversity from both H. incongruens and H. barbara. We discuss the possible origin of apomictic lineages as a result of independent transition episodes to apomixis from different sexual ancestors. Time of divergence reflected the genetic differentiation within and among multiple ancestors and different possible routes to parthenogenesis.

Treatment of microbiologically polluted aquaculture waters by a novel photochemical technique of potentially low environmental impact.

The applicability of a novel procedure for the disinfection of microbiologically polluted waters from fish-farming ponds, based on the combined action of visible light (including sunlight) and porphyrin-type photosensitising agents, has been investigated using (a) cell cultures of a Gram-positive bacterium (meticillin-resistant Staphylococcus aureus), a Gram-negative bacterium (Escherichia coli) and a fungal pathogen (Saprolegnia spp.); (b) pilot aquaculture plants involving either spontaneously or artificially Saprolegnia-infected rainbow trout (Oncorhynchus mykiss). The results obtained by using two cationic porphyrins, namely a tetra-substituted N-methyl-pyridyl-porphine (C1) and its analogue where one N-methyl group had been replaced by a N-tetradecyl chain (C14), and low intensity visible light irradiation showed an extensive (up to 6-7 log) decrease in the bacterial/fungal population after short incubation and irradiation times in the presence of micromolar photosensitiser concentrations. Moreover, C14 showed some toxic effect also in the absence of light. Extension of these studies to the pilot plants indicated that both C1 + light and C14 can prevent Saprolegnia infections or promote the cure of saprolegniasis in infected trout by treatments with submicromolar porphyrin doses. The procedure appears to be of low cost and to have a low environmental impact.

Evidence of recombination in putative ancient asexuals.

Ancient asexuals have been considered to be a contradiction of the basic tenets of evolutionary theory. Barred from rearranging genetic variation by recombination, their reduced number of gene arrangements is thought to hamper their response to changing environments. For the same reason, it should be difficult for them to avoid the build-up of deleterious mutations. Several groups of taxonomically diverse organisms are thought to be ancient asexuals, although clear evidence for or against the existence of recombination events is scarce. Several methods have recently been developed for predicting recombination events by analyzing aligned sequences of a given region of DNA that all originate from one species. The methods are based on phylogenetic, substitution, and compatibility analyses. Here we present the results of analyses of sequence data from different loci studied in several groups of evolutionarily distant species that are considered to be ancient asexuals, using seven different types of analysis. The groups of organisms were the arbuscular mycorrhizal fungi (Glomales), Darwinula stevensoni (Darwinuloidea crustacean ostracods) and the bdelloid rotifers (Bdelloidea), which are thought to have been asexual for the last 400, 25-100, and 35-40 Myr, respectively. The seven different analytical methods evaluated the evolutionary relationships among haplotypes, and these methods had previously been shown to be reliable for predicting the occurrence of recombination events. Despite the different degree of genetic variation among the different groups of organisms, at least some evidence for recombination was found in all species groups. In particular, predictions of recombination events in the arbuscular mycorrhizal fungi were frequent. Predictions of recombination were also found for sequence data that have previously been used to infer the absence of recombination in bdelloid rotifers. Although our results have to be taken with some caution because they could signal very ancient recombination events or possibly other genetic variation of nonrecombinant origin, they suggest that some cryptic recombination events may exist in these organisms.