Lecane Quadridentata Research Articles

Işıklı Gölü (Çivril-Denizli/Türkiye) zooplankton dağılımı ve kompozisyonunun trofik durum değerlendirmesi ile araştırılması

In this study, the zooplankton distribution and composition of Işıklı Lake, located in the Inner West Anatolia region of Türkiye, were examined monthly between 2003-2005. Zooplankton samples were collected with Hydro-Bios plankton net (55 µm) at the surface and fixed in formaldehyde (4 %). Physiological parameters such as surface water temperature, pH, dissolved oxygen, and conductivity were also measured. Also, the frequency index (F %) and the Brachionus / Trichocerca (QB/T) were determined to assess the trophic composition of Lake Işıklı. A total of 49 species have been identified. Rotifera (55 %), Cladocera (27 %) and Copepoda (18%) were represented by the species. The maximum species was found in May 2004 (21 species), while the minimum was found in October 2003 (5 species). Asplanchna priodonta, Keratella cochlearis, Keratella tecta, Polyarthra dolichoptera, Synchaeta pectinata, Bosmina longirostris and Chydorus sphaericus are common species in the lake. The water temperature varied between 3.9-24.6 °C; pH ranged from 8.1 to 8.8; the electrical conductivity ranged from 341 µS/cm to 434 µS/cm; the dissolved oxygen values changed from 5.8 mg/L to 11.1 mg/L. According to the frequency index (F %), the most dominant species are B. longirostris (74 %), K. cochlearis (62 %), A. priodonta (54 %), and C. sphaericus (51 %). A total of 20 species are reported for the first time from the region. Newly reported species from the lake were: the rotifers, A. priodonta, Brachionus angularis, Brachionus calyciflorus, Colurella colurus, Keratella quadrata, Lecane clostrocerca, Lecane ludwigi, Lecane luna, Lecane lunaris, Lecane ohioensis, Lecane quadridentata, Lecane sp., Mytilina mucronata, Notholca acuminata, Notholca squamula, Trichotria tetractis, the cladocerans Acroperus harpae, Daphnia cucullata, and the copepods Eucyclops macrurus and Megacyclops gigas. Considering the Brachionus / Trichocerca (QB/T) ratio according to the Sládeček (1983) index, the lake showed mesotrophic features.

Characterization and Determination of the Toxicological Risk of Biochar Using Invertebrate Toxicity Tests in the State of Aguascalientes, México

Following a quantitative analysis of adequate feedstock, comprising 11 woody biomass species, four biochars were generated using a Kon-Tiki flame curtain kiln in the state of Aguascalientes, Mexico. Despite the high quality (certified by European Biochar Certificate), the biochars contain substantial quantities of hazardous substances, such as polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, and heavy metals, which can induce adverse effects if wrongly applied to the environment. To assess the toxicity of biochars to non-target organisms, toxicity tests with four benthic and zooplanktonic invertebrate species, the ciliate Paramecium caudatum, the rotifer Lecane quadridentata, and the cladocerans Daphnia magna and Moina macrocopa were performed using biochar elutriates. In acute and chronic toxicity tests, no acute toxic effect to ciliates, but significant lethality to rotifers and cladocerans was detected. This lethal toxicity might be due to ingestion/digestion by enzymatic/mechanic processes of biochar by cladocerans and rotifers of toxic substances present in the biochar. No chronic toxicity was found where biochar elutriates were mixed with soil. These data indicate that it is instrumental to use toxicity tests to assess biochars’ toxicity to the environment, especially when applied close to sensitive habitats, and to stick closely to the quantitative set-point values.

Bioconcentration of Lead and x-ray Microanalysis with SEM in the Freshwater Rotifer Lecane quadridentata (Rotifera: Monogononta)

Bioconcentration of Lead and x-ray Microanalysis with SEM in the Freshwater Rotifer Lecane quadridentata (Rotifera: Monogononta)

Monitoreo de una planta tratadora de aguas residuales mediante pruebas de toxicidad aguda con el cladócero Daphnia magna y el rotífero de agua dulce Lecane quadridentata

Background. Monitoring of physicochemical parameters and acute toxicity tests allow us to measure water quality of the influent and effluent of wastewater treatment plants in accordance with the parameters established by the NOM-003-SEMARNAT-1997. Goals. We measured water quality of the influent and effluent of the wastewater treatment plant of the Autonomous University of Aguascalientes during 2007-2008. Methods. Every 15 days physicochemical parameters were taken and acute toxicity tests were conducted with the cladoceran Daphnia magna and the rotifer Lecane quadridentata. Results. The influent showed median lethal concentration to be between 25.71 and 3.88 toxic units with L. quadridentata, while with D. magna the median lethal concentration was between 31.51 and 3.17 toxic units. The effluent showed median lethal concentration to be between 60.71 and 1.64 toxic units with L. quadridentata, whereas the D. magna showed no toxicity. Conclusions. We concluded that the wastewater treatment plant of the Autonomous University of Aguascalientes in 2007-2008 fulfilled Mexico´s water quality criteria after treatment.

Adverse effects and bioconcentration of chromium in two freshwater rotifer species

Bioaccumulation of trivalent (CrIII) and hexavalent chromium (CrVI), and its adverse effects were studied in two rotifer species: Brachionus calyciflorus (two different strains), and Lecane quadridentata. Median Lethal Concentration (LC50) at 24 h of both species showed that CrVI is highly toxic: LC50 ranges from 4.7 × 10−5 to 4 × 10−6 mg L−1), compared with CrIII: LC50 ranges from 0.64 to 1.279 mg L−1. Using the LC50 as an exposure concentration, and using atomic absorption, the bioconcentration factor (BCF) was obtained and BCFs of rotifers exposed to CrIII are four orders of magnitude lower than BCFs of rotifers exposed to CrVI. The effect of Cr on the elemental composition of the two species of rotifers in their structures by X-ray microanalysis by energy dispersion showed that Cr is found in intoxicated rotifers, but not in control rotifers. The basal immunoreactivity to metallothioneins is greater in B. calyciflorus than L. quadridentata. The immunoreactivity to metallothioneins decreases in B. calyciflorus when is exposed to CrIII, in contrast in L. quadridentata the immunoreactivity to metallothioneins increase when is exposed to CrIII, and the immunoreactivity to CrVI in L. quadridentata decrease. A mechanism is proposed in which the harder lorica of L. quadridentata acts as a barrier and accumulator of CrVI, and allows for attenuating responses like metallothionein production in L. quadridentata. Instead, in B. calyciflorus the lack of a harder lorica allows for deeper penetration of CrVI, and no time to produce attenuating measures.

Cholinergic neuromuscular junctions in Brachionus calyciflorus and Lecane quadridentata (Rotifera: Monogononta)

Objective: To identify the presence of joint muscular and cholinergic systems in two freshwater rotifer species, Brachionus calyciflorus and Lecane quadridentata. Methods: The muscle actin fibers were stained with phalloidin-linked fluorescent dye, and acetylcholine was detected with Amplex Red Acetylcholine/Acetylcholinesterase Assay Kit, and then confocal scanning laser microscopy was used. Results: The musculature of Brachionus calyciflorus showed a pattern similar to other species of the same genus, while that of Lecane quadridentata was different from other rotifer genera described previously. The cholinergic system was determined by co-localization of both muscles and acetylcholine labels in the whole rotifer, suggesting the presence of neuromuscular junctions. Conclusions: The distribution pattern of muscular and acetylcholine systems showed considerable differences between the two species that might be related to different adaptations to particular ecological niches. The confirmation of a cholinergic system in rotifers contributes to the development of potential neuro-pharmacological and toxicological studies using rotifers as model organism. Peer reviewer

An assessment of chemical and physical parameters, several contaminants including metals, and toxicity in the seven major wastewater treatment plants in the state of Aguascalientes, Mexico

Forty-eight hours acute toxicity tests were employed with Daphnia magna and Lecane quadridentata to assess the influents and effluents of the seven most important wastewater treatment plants (WTP) in the state of Aguascalientes, Mexico, during the 2006 dry and rainy seasons. The WTP of the City of Aguascalientes treated 1948 Ls−1. The remaining six plants treated wastewater in the range from 28 to 93 Ls−1. Plants efficiently removed toxicity when Daphnia magna was used as a model organism, but performed poorly when the freshwater rotifer Lecane quadridentata was employed. It was observed that biochemical oxygen demand (BOD5), chemical oxygen demand (COD), conductivity, dissolved oxygen (DO), pH, phenol, methylene blue active substances (MBAS), temperature, and total suspended solids (TSS) were within the maximum allowed levels (MAL) in the effluents during the rainy season. Whereas the BOD5, total nitrogen, total dissolved solids (TDS) and TSS showed levels greater than the MAL in effluents during the dry season. The levels of BOD, MBAS, and total nitrogen were greater than the MAL in influents. In contrast, the values of TDS and TSS in influents were above the MAL during the rainy season. In the dry season the levels of aluminum (Al), iron (Fe), zinc (Zn), manganese (Mn), chromium (Cr), mercury (Hg) and lead (Pb) in influents and Fe, Mn and Pb in effluents were above the MAL. During the rainy season the levels of Mn, Cr and Hg in influents and those of Mn in effluents were above the MAL. When D. magna was used as model organism, acute toxicity units (aTU) for influents ranged from 0.2 to 4.4 and from 0.1 to 0.2 for effluents. These values for effluents are acceptable according to international guidelines. However, when L. quadridentata was the model organism, ranges were from 2.0 to 8.3 aTU in influents and from 1.6 to 2.6 aTU in effluents. The treated water that discharges into the San Pedro River would be considered toxic. The results of the toxicity tests demonstrated that the freshwater rotifer Lecane quadridentata was more sensitive (in 89.3% of the samples) than the cladoceran Daphnia magna when both organisms were exposed to the influents and effluents of the wastewater treatment plants.

Population level indicators of stress: Effects of two heavy metals (copper and mercury) on the growth of Lecane quadridentata (Ehrenberg, 1830) (Rotifera: Lecanidae)

We quantified the population level responses of Lecane quadridentata exposed separately to five different concentrations of Cu (0.3125, 0.625, 1.25, 2.5 and 5.0 μ g/L as CuSO4) and Hg (0.0844, 0.1688, 0.3375, 0.675 and 1.35 μ g/L as HgCl2) at 23°C and under an algal food density of 1 × 106 cells/mL of Chlorella vulgaris for 24 days. We derived peak population densities and the rate of population increase (r) per day in both controls and in heavy metal treatments. In general, the population growth of L. quadridentata decreased with increasing concentration of Cu or Hg in the medium. The growth was similar in controls and in the lowest tested concentration of Cu (0.3125 μ g/L), whereas in Hg treatments, even at the lowest tested concentration (0.0844 μ g/L), there was a drastic decline of rotifer densities. The peak population densities in controls were 63± 5 ind./mL, whereas in heavy metal treatments, they ranged from 1 to 58 ind./mL depending on the concentration. The rate of population increase also decreased with increasing concentration of Cu or Hg. In general, the r varied from +0.23± 0.01 to -0.12± 0.02, depending on the metal type and concentration. The differences in the population level responses of L. quadridentata to Cu and Hg were interpreted in terms of relative toxicity of the chosen heavy metals. Since our study showed that peak population density was also sensitive to metal stress, we recommend the use of this variable together with the rate of population increase in ecotoxicological evaluations.

Implementing Lecane quadridentata acute toxicity tests to assess the toxic effects of selected metals (Al, Fe and Zn) ,

An environmental study revealed that three metals (Al, Fe and Zn) are common in the San Pedro River (SPR) (Aguascalientes, Mexico). Regrettably, in many samples the concentrations of these metals exceeded the maximum allowed toxicant concentrations levels as defined in by Mexican legislation. The highest concentrations of the three metals were found during the 2005 dry season, with elevated Al concentrations present along the entire river. Not surprisingly, the highest concentrations for all three metals came from locations adjacent to industrial areas. Estimates of the contribution of these metals to total toxicity revealed that these three metals are important contaminants of the river and responsible for most of the lethal toxicity found in environmental samples. To assess the importance of these reports, we conducted acute toxicity tests to determine LC50 for Al, Fe and Zn on the freshwater rotifer Lecane quadridentata. This permitted us to estimate the contribution of these metals to total toxicity during 2005–2006. Based on LC50 values, all three metals should be considered very toxic, with the zinc LC50 value (0.12 mg L −1) making it the most toxic metal for L. quadridentata. This approach can be applied to other sites with similar concentrations of these metals.

The Spatial Segregation of Zooplankton Communities with Reference to Land Use and Macrophytes in Shallow Lake Wielkowiejskie (Poland)

AbstractThe spatial distribution of zooplankton in relation to two types of land‐use (forested and pastoral‐arable) of a lake's surroundings and to various habitats (helophytes, elodeids, nymphaeids and open water) was examined along 16 parallel transects on a macrophyte‐dominated lake (area – 13.3 ha; mean depth – 1.4 m). The type of habitat was the main determinant of zooplankton community structure. Dissected‐leaved elodeids harboured the richest and most abundant community with typically littoral (e.g., Colurella uncinata) and pelagic species (e.g., Keratella cochlearis). Two species (Polyarthra major and P. vulgaris) selectively chose the open water and one (Lecane quadridentata) the Typha stand. No spatial differentiation in zooplankton abundance was recorded between the two types of the catchment area. One possible explanation may be the shallowness and small area of this lake which may support full mixing and no difference in physical‐chemical gradients. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The diurnal distribution of the zooplankton community of the littoral zone of Lake Wielkowiejskie (Wielkopolski National Park, Poland)

Abstract The main aim of this study was to analyze the diel distribution of zooplankton communities within the zones of Nymphaea albae, Myriophyllum verticillatum, and Typha angustifolia, and, compared to that, in the open water area of a lake. It also aimed to analyze the relationship between zooplankton densities and the concentration of physicochemical factors and chlorophy11 a content. A total of 149 zooplankton taxa were noted, and, despite the narrow range of the research in the analyzed lake, some rare species were noted, among which two - Colurella sinistra and Lecane inopinata - were recorded for the first time among Polish fauna. The rush zone was taxonomically the richest, while the open water area was the poorest. The highest number of individuals was observed in the Myriophyllum bed, while the lowest was noted in the zone dominated by Nymphaea alba. The highest densities of zooplankton occurred at dusk, while the lowest occurred during the day, irrespective of the sampling station. Because Lake Wielkowiejskie is a shallow and macrophyte-dominated water body, the differences in the diurnal distribution of zooplankton communities may suggest horizontal migrations between the pelagic zone and the phytolittoral, as well as between particular macrophyte stands. A positive correlation between the densities of some zooplankters and the concentration of chlorophyll a was found, while a negative relationship with the concentration of nitrites was recorded for Lecane quadridentata and Alonella nana.

Analysis of the toxicity of glyphosate and Faena® using the freshwater invertebrates Daphnia magna and Lecane quadridentata

With the present contribution an evaluation of the toxicity of the pure herbicide glyphosate and its commercial formulation Faena® is reported using the cladoceran Daphnia magna Strauss and the rotifer Lecane quadridentata Ehrenberg. LC50, EC50, NOEC, and LOEC values for each toxicant and for both test organisms are obtained. Regarding acute toxicity, Faena was 11-fold more toxic to L. quadridentata than pure glyphosate and slightly more toxic to D. magna (1.7-fold). Inhibition of esterase activity in L. quadridentata by glyphosate was the most sensitive end-point; the EC50 was 1500-fold smaller than the LC50. The implications of these results and their comparison with established international and national limit values for glyphosate are discussed.

Identification of exocytotic membrane proteins in three rotifer species

We confirmed the presence and expression of exocytotic membrane proteins: Syntaxin-1, Syntaxin-4, SNAP-23, and SNAP-25 in the rotifers Brachionus calyciflorus, Lecane quadridentata, and Philodina roseola. These proteins were identified by immunohistochemistry and immunoblot analysis using antibodies against Syntaxin-1, Syntaxin-4, SNAP-23, and SNAP-25. The presence of these proteins were observed mainly in regions of the nervous, reproductive, and glandular systems of these rotifer species, which underlines the fundamental role of exocytotic docking and fusion membrane proteins in the vesicular release of secretory proteins. The immunoblot analysis confirmed the expression of Syntaxin-1, Syntaxin-4, and SNAP-23 in the three rotifer studied, but not of SNAP-25. This study contributes to rotifer biology by revealing the presence of conservative exocytotic machinery such as SNAREs proteins in the phylum Rotifera, including members of the Class Bdelloidea the highest taxa of metazoans where sexual reproduction does not exist.

Study of the effects of Pb and Hg toxicity using a chronic toxicity reproductive 5-day test with the freshwater rotiferLecane quadridentata

We have developed chronic toxicity reproductive 5-day tests to study the effects of Pb, as Pb(NO(3))(2), and Hg, as HgCl(2), exposure in the freshwater rotifer Lecane quadridentata. We used "r" (the instantaneous growth rate) as the endpoint. The test was performed using EPA medium at two food levels (10(5) and 10(6) cells/mL of Nannochloris oculata) at a controlled temperature of 25 degrees C and an L/D cycle of 16:8 h. We monitored the levels of both metals, using atomic absorption, at days 0, 2, and 5 of each experiment. Our results showed that rotifers fed at higher food concentrations were capable of withstanding higher levels of metal toxicity than those fed at lower food concentrations (EC50 = 0.704 versus 0.664 mg/L(-1) for lead, P < 0.05; EC50 = 0.057 versus 0.054 for mercury, P < 0.05). Our atomic absorption analysis showed that although 66% of lead nitrate can be taken up by algal cells efficiently and removed from the medium, rotifers also play an important role removing additional lead from the medium (up to 44% in some treatments). In the case of mercuric chloride, most of the mercury is bound by the salts contained in EPA medium or discarded by the organisms, and the remainder is removed by N. oculata in <48 h.

Effect of coexposure to DDT and manganese on freshwater invertebrates: Pore water from contaminated rivers and laboratory studies

An environmental survey of several rivers of the southern Huasteca area of Mexico revealed high concentrations of manganese (Mn) and the presence of DDT in the sediments and pore water. Therefore, acute (48-h) toxicities of Mn and DDT were assessed both independently and as a combination on 24-h-old neonates of Daphnia magna Strauss and Lecane quadridentata Ehrenberg. Daphnia magna showed high sensitivity to both toxicants, whereas L. quadridentata was highly resistant to DDT and less susceptible to Mn. For D. magna, the Mn and DDT coexposure was significantly more toxic than any of the singly tested compounds. When D. magna was exposed to sediment pore water, no association was found between the Mn content in the samples and the observed toxicity. Preliminary particle analysis of pore water showed different compounds of Mn, which apparently were not in bioavailable form.

Phospholipase A2 activity in three species of littoral freshwater rotifers exposed to several toxicants.

We analyzed three species of Lecane, a littoral rotifer, for susceptibility to six metals and four organic toxicants using a fluorometric assay based on inhibition of activity of the enzyme phospholipase A2. The metallic toxicants that we tested included Cd, Cr, Cu, Pb, Hg (as HgCl2), and Ti; the organic toxicants included benzene, ethyl acetate, toluene, and vinyl acetate. The three species differed greatly with respect to their susceptibility to the various toxicants. Lecane quadridentata, for example, was particularly sensitive to the four organic compounds (median effective concentration values [EC50] ranged from 6.6 x 10(-4)-0.987 mg/L). Lecane luna, in contrast, seemed particularly sensitive to metals (EC50 values ranged from 2 x 10(-6)-1.92 mg/L). Lecane hamata was relatively insensitive to organic solvents (EC50 values ranged from 4.25-126.5 mg/L).

Food Type Effects on the Population Growth Patterns of Littoral Rotifers and Cladocerans

AbstractLittoral rotifers and cladocerans feed on bacteria, phytoplankton, and detritus. In comparison to planktonic organisms their species diversity is high, yet little is known about their biology. In this study we present data on the functional response of the cladocerans Macrothrix triserialis and Alona rectangula, and the rotifer Brachionus macracanthus to different levels of the alga Chlorella vulgaris. Based on the incipient limiting level, we chose the food concentration and tested the population growth on four types of diets for three cladoceran species — Macrothrix triserialis, Alona rectangula, and Chydorus sphaericus — and three rotifer species — Brachionus macracanthus, Lecane quadridentata, and Platyias quadricornis. We studied growth rates of each of these species on diets of live Chlorella vulgaris, heat‐killed Chlorella vulgaris, baker's yeast (Saccharomyces cerevisiae), and field collected detritus. The incipient limiting level was around 0.9 · 106 cells mL−1 of Chlorella for the tested zooplankton species. The population growth patterns showed that, in general, the cladocerans took 25…50 d to reach their peak population densities, which ranged from 10…75 ind. mL−11. Among the rotifers L. quadridentata and B. macracanthus had equally high growth rates on live and heat‐killed forms of C. vulgaris while P. quadricornis grew best on detritus. The growth rates ranged from 0.03…0.21 d−1. The similarities and differences between littoral and planktonic organisms in relation to food type and availability have been discussed.

Composição do Zooplâncton em diferentes ambientes do lago Camaleão, na ilha da Marchantaria, Amazonas, Brasil

Este trabalho teve o objetivo de verificar a ocorrência e a distribuição dos principais grupos de zooplâncton em três diferentes sub-habitats do lago Camaleão: canal, macrófitas aquáticas e floresta alagada, no período de cheia (agosto de 1996). Nos três ambientes estudados, Cladocera, Copepoda e Rotifera ocorreram com abundância relativa diferentes. No canal, Cladocera ocorreu com maior número de espécies e de indivíduos, sendo dominante a espécie Bosminopsis deitersi (89%). Na floresta alagada Cladocera e Copepoda foram igualmente dominantes, ressaltando-se que somente ocorreram as formas imaturas de copépodes, náuplios e copepoditos. Nas macrófitas, o grupo de maior ocorrência foi Rotifera, com a dominância de Lecane quadrídentata, Keratella americana e Brachionus patulus seguido de copépodes (formas imaturas) e de cladóceros, estes na maioria da família Chydoridae (21.4%).

Mating behavior in eight rotifer species : using cross-mating tests to study species boundaries

We characterized the mating behavior of eight freshwater rotifer species from five different families of Monogononts (Asplanchnidae, Brachionidae, Euchlanidae, Lecanidae, and Trichocercidae). Were corded the percentages of male-female encounters resulting in mating attempts and the number of completed copulations. The characterization of mating behavior also included data on: (1) duration of copulation, (2) female and male swimming speed, (3) sites of initial mating attempts, (4) sites of copulation, and (5) sizes of males and females. In the five families investigated, cross-mating tests may be used to assess the ability of males to discriminate conspecifics, establishing limits to gene flow. We also present data on two families, Brachionidae and Lecanidae where we used cross-mating tests to compare discrimination between conspecific females and those of other species. Brachionus calyciflorus males attempted mating with females of the closely related genus Plationus, but did not attempt mating with Keratella Americana females. Males of other three Brachionidae species only attempted mating with nonspecific females. Lecane quadridentata males attempted to mate with females of two different Lecane species besides their own. Percentages of mating attempts and completed copulations were quantified in all crosses. Lower percentages of copulation after a mating attempt were found among brachionids than among non-brachionids. These data demonstrate that male discrimination of females is an effective pre-mating reproductive barrier in several species of Monogonont rotifers. These results, further suggest that investigations of mating behavior are useful for determining species boundaries in rotifers and perhaps other zooplankters.