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12 result(s) for "Polycera"
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Performance and resilience of the PolyCera® Titan membrane for industrial wastewater treatment
This research aims to evaluate the performance of PolyCera® Titan membrane for different wastewater treatment. Membrane filtration of several cycles was conducted in understanding the fouling mechanism, fouling propensity, and defouling potential of the PolyCera® Titan which had not been studied by any other researcher before. The PolyCera® Titan membrane is effective for the treatment of textile industry wastewater, palm oil mill effluent (POME), leachate, and semiconductor-industry wastewater. Rejection of methylene blue (MB) and Congo red (CR) was in the range of 78.76–86.04% and 88.89–93.71%, respectively; 94.72–96.50% NaCl, 96.07–97.62% kaolin, and 97.26–97.73% glucose were rejected from synthetic leachate indicating the removal of TDS, TSS, and COD from the leachate, respectively. Standard blocking and complete model were the best models used to explain the PolyCera® Titan membrane fouling mechanism in all types of wastewater treatment processes with a high R2 value. Physical cleaning with the use of distilled water was able to recover the permeate flux with the flux recovery ratio (FRR) value in the range of 79.2–95.22% in the first cycle, 81.20–98.16% in the second cycle, and 86.09–95.96% in the third cycle.
Polycera norvegica is a valid species, and a plea for good taxonomic practices – a reply to Korshunova et al., 2021
In this letter we highlight the inconsistencies and dismantle the arguments used by Korshunova et al. (2021) where the authors have treated the nudibranch species Polycera norvegica as a junior synonym of Polycera capitata (original designation: Thecacera capitata). We show that in accordance with the International Code of Zoological Nomenclature, Thecacera capitata should be considered a nomen dubium, and we reinstate Polycera norvegica as the valid name of this species.
Integrative taxonomy reveals a cryptic species of the nudibranch genus Polycera (Polyceridae) in European waters
This work aimed to test whether the colour variability featured by the European nudibranch Polycera quadrilineata is consistent with the concept of a single polychromatic species or may hide multiple lineages. Samples from across the geographic range of P. quadrilineata together with representatives from worldwide species with a focus on Atlantic diversity, were gathered and studied using an integrative taxonomic approach. Morpho-anatomical characters were investigated by light and scanning electron microscopy. Bayesian molecular phylogenetics using MrBayes, the Automatic Barcode Gap Discovery species delimitation method, and haplotype network analysis using the PopArt software were employed to help delimit species using the mitochondrial gene cytochrome c oxidase subunit I (COI). The results supported the existence of a second species, here described and named Polycera norvegica sp. nov., only known from Norway where it is sympatric with P. quadrilineata. The COI uncorrected p-genetic distance between the two species was estimated at 9.6–12.4%. Polycera norvegica sp. nov. differs by exhibiting a black dotted or patchy dotted pattern occasionally with more or less defined orange/brown patches, but never black continuous or dashed stripes as in P. quadrilineata. The two species share a common colouration with a whitish base and yellow/orange tubercles. Anatomically, P. norvegica sp. nov. has a weaker labial cuticle, a smaller radula with fewer rows, and only four marginal teeth, a reproductive system with a single lobed bursa copulatrix, shorter reproductive ducts, and a penis armed with two kinds of spines: needle-like and hook-shaped penile spines.
New contributions to the subfamily Polycerinae (Nudibranchia, Polyceridae): description of three new species and one new genus
The subfamily Polycerinae includes eight genera, from the monospecific Lamellana and Lecithophorus to the diverse Polycera and Gymnodoris, with 33 and 26 valid species, respectively. The monophyly of the subfamily has been tested by molecular data although not all genera were included. To date, relationships within the subfamily are not supported. In the present paper, three new species of polycerid nudibranchs are fully described based on specimens collected in Marshall Islands and Australia: one Palio species (Palio gaeli sp. nov.), one Polycera species (Polycera nimbsi sp. nov.) and a new genus (Paliota galactica gen. and sp. nov.). The new genus is described based on its peculiar radular teeth and genetic divergence. The internal anatomy was studied by dissections and scanning electron microscope photographs. Partial sequences of mitochondrial cytochrome oxidase c subunit I (COI) and 16S ribosomal RNA (16S) as well as nuclear histone H3 (H3) were also obtained. A phylogenetic framework for two of these three species is proposed, also including for the first time the species Paliolla templadoi and Polycera melanosticta.
Exploring Echinops polyceras Boiss. from Jordan: Essential Oil Composition, COX, Protein Denaturation Inhibitory Power and Antimicrobial Activity of the Alcoholic Extract
In this article, we present the first detailed analysis of the hydro-distilled essential oil (HDEO) of the inflorescence heads of Echinops polyceras Boiss. (Asteraceae) from the flora of Jordan, offering observations at different growth (pre-flowering, full-flowering and post-flowering) stages. Additionally, we investigated the methanolic extract obtained from the aerial parts of the plant material at the full flowering stage in order to determine its inhibitory activity in terms of COX and protein denaturation and evaluate its antimicrobial effects against S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria. Performing GC/MS analysis of HDEO, obtained from the fresh inflorescence heads at the different growth stages, resulted in the identification of 192 constituents. The main class of compounds detected in these three stages comprised aliphatic hydrocarbons and their derivatives, which amounted to 50.04% (pre-flower), 40.28% (full-flower) and 41.34% (post-flower) of the total composition. The oils also contained appreciable amounts of oxygenated terpenoids, primarily sesquiterpenoids and diterpenoids. The pre-flowering stage was dominated by (2E)-hexenal (8.03%) in addition to the oxygenated diterpene (6E,10E)-pseudo phytol (7.54%). The full-flowering stage primarily contained (6E,10E)-pseudo phytol (7.84%), β-bisabolene (7.53%, SH) and the diterpene hydrocarbon dolabradiene (5.50%). The major constituents detected in the HDEO obtained at the post-flowering stage included the oxygenated sesquiterpenoid intermedeol (5.53%), the sesquiterpene hydrocarbon (E)-caryophyllene (5.01%) and (6E,10E)-pseudo phytol (4.47%). The methanolic extract obtained from air-dried aerial parts of E. polyceras displayed more COX-2 inhibition than COX-1 inhibition at a concentration level of 200 µg/mL. The extract exhibited a capacity to inhibit protein denaturation that was comparable with respect to the activity of diclofenac sodium and displayed moderate levels of antimicrobial activity against both bacterial species. The current results demonstrate the need to perform further detailed phytochemical investigations to isolate and characterize active constituents.
First molecular phylogeny of the subfamily Polycerinae (Mollusca, Nudibranchia, Polyceridae)
The subfamily Polycerinae includes four genera with around 46 species described to date. This subfamily is characterized by a limaciform body, which may have simple tentacular processes on the margin of the oral veil. Phylogenetic relationships between the genera of the subfamily Polycerinae (Polyceridae) have not yet been studied, and therefore, the only available information is based on morphological descriptions. The present study reports the first phylogenetic analysis of Polycerinae based on the mitochondrial genes cytochrome oxidase subunit I and the large ribosomal subunit (16S rRNA) using maximum likelihood and Bayesian methods. Our results showed that Polycerinae is monophyletic, but the relationships within the subfamily as well as within Polycera remain unresolved. A key finding of this study is that there are clearly two sympatric species of Polycera present in South Africa: Polycera capensis Quoy and Gaimard, 1824 also found in Australia and an undescribed Polycera sp. On the other hand, the studied specimens of the genus Gymnodoris were clustered within Polycerinae, reopening the problem of the systematic position of this genus. Additional genes and species of Polycerinae and Gymnodoris would provide more information and probably fully resolve this situation.
Endobacteria in the tentacles of selected cnidarian species and in the cerata of their nudibranch predators
This is the first genetic analysis comparing cultured endobacteria discovered in the tentacles of cnidarian species ( Tubularia indivisa, Tubularia larynx, Corymorpha nutans, Sagartia elegans ) with those found in the cerata tips of selected nudibranch species ( Berghia caerulescens, Coryphella lineata, Coryphella gracilis, Janolus cristatus, Polycera faeroensis, Polycera quadrilineata, Doto coronata, Dendronotus frondosus ). Shared pathogenic activities were found among other microorganisms in the Pseudoalteromonas tetraodonis group (TTX), and the Vibrio splendidus group (haemolytic, septicaemic, necrotic activity). Specific autochthonous endobacteria of extremely low similarity to their next neighbours were detected in nudibranch cerata. These organisms are regarded as new and unknown endobacteria; among them were Pseudoalteromonas luteoviolacea (95%), Orientia tsutsugamushi (84%), Gracilimonas tropica (96%), Balneola alkaliphia (95%), Loktanella rosea (97%). SEM micrographs provide insight into endobacterial aggregates in cnidarian tentacles and nudibranch cerata. Since certain nudibranch predators prey on cnidarian species, it is assumed that cnidarian tentacle bacteria are directly transferred to nudibranch cerata. The pathogenic endobacteria may contribute to the chemical defence of both the nudibranch and cnidarian species investigated.
New Methodology for Quantifying the Effects of Perennials on Their Patch Productivity in Semi-arid Environments
The correlations between perennials and the herbaceous productivity in patches occupied by them were previously studied and several descriptive models were defined. Yet these studies focused on either single or several species without analyzing higher numbers and ranking their effects. Here we describe a handy analytical methodology which allows separating the effects of each perennial species on herbaceous productivity at its respective patches from those of the others in a given area, even in case of complex patches containing several species. The described methodology also allows analysts to correlate the effect of perennials to their patch sizes and the respective herbaceous biomass. Additional mathematical analysis presented here succeeded in differentiating between the perennial species stand-alone presence effect on the herbaceous productivity and that attributed to the canopy size. In addition, the effects of location along the slope and its rockiness outlines were studied. As a case study, we chose representative sloped shrubland with rockiness outlines, located in Yattir farm, Northern Negev, Israel. Based on the described analyses we found that the species with the highest positive effects on the herbaceous productivity were Echinops polyceras, Echium angustifolium, and Salvia lanigera. Contradictory effects were observed in case of Thymelea hirsute, Anchusa ramosus, and Noaea mucronata. Collectively, the presented methodology could be an important management tool for monitoring the herbaceous biomass amounts in a given shrubland.
Second record of the Indo-Pacific nudibranch Polycera hedgpethi from Atlantic European waters (Gastropoda, Nudibranchia, Polyceridae)
The alien nudibranch Polycera hedgpethi Er. Marcus, 1964, has been found in the Gulf of Cádiz (El Portil, Huelva). The present record in the Gulf of Cadiz could be considered an opportunity to connect the isolated Eastern Atlantic records for this species with those from the Mediterranean, even taking into consideration the possible unreported presence of this species along the North African Mediterranean coast. The collected specimens exhibited reproductive behaviour, suggesting the possibility of future additional records for this locality.
Some aspects of the reproductive biology of two Atlantic species of Polycera (Mollusca: Opisthobranchia)
Spawn and the embryonic development of two species of the genus Polycera were studied. Both species, Polycera aurantiomarginata and Polycera quadrilineata, were collected in the intertidal zone of El Portil (Huelva) in south-western Spain. In the laboratory spawn were collected daily. Length and width of the spawn, number of eggs per mm2, egg size and capsule size were measured. The egg masses were controlled several times a day to provide a timetable for the main developmental events until hatching. Embryonic growth was measured between some characteristic stages (gastrula, preveliger, primordial velum and veliger prior to hatch). The two species differ in a number of aspects: spawn are longer, eggs and capsules are bigger in P. aurantiomarginata than in P. quadrilineata. The number of eggs per mm2, however, is greater in P. quadrilineata than in its congener. Furthermore, spawn of P. quadrilineata are semicircular whereas those of P. aurantiomarginata are spiral and wavy. Both species show planktotrophic development but embryonic development of P. quadrilineata is faster than that of P. aurantiomarginata. The dynamic of embryonic growth is very similar in the two species, although embryos of P. aurantiomarginata are larger at any measured stage than those of P. quadrilineata.