Effects of three biological control approaches and their combination on the restoration of eutrophicated waterbodies

Choosing appropriate approaches is a key to successfully using biological control measures to accelerate the recovery of eutrophic waterbodies. In this study, we used three biomanipulation approaches—including introducing filter-feeding bivalves, stocking planktivorous fish, replanting submerged macrophytes—as well as an approach that combined all three of these methods in order to investigate their effects on water quality and plankton communities within simulation experiment systems. The experimental results showed that only stocking filter-feeding bivalves or fish could not significantly control the total algal biomass and water nutrient concentrations compared to those of the controls. The cladoceran biomasses were reduced under the treatments of stocking filter-feeding bivalves or fish. However, replanting macrophytes and a combined biological restoration approach could significantly reduce the algal biomass and the nutrient content, and both of these methods increased cladoceran biomass. The results of factor analysis of ten environmental parameters suggested that a combined biological restoration treatment was the most effective at controlling the algal biomass and reducing the nutrient content. In conclusion, combination of biological restoration measures was the best treatment out of the three treatments that were tested, and we suggest that more whole-lake scale experiments are needed. Additionally, designing a combined approach should not be a simple superposition of individual measures, but the measures should be complementary to each other.     

Cytotoxicity,apoptosis, DNA damage and methylation in mammary and kidney epithelial cell lines exposed to ochratoxin A

This study aimed to investigate the in vitro damage induced by ochratoxin A (OTA) in BME-UV1 and MDCK epithelial cells. Both cells lines were treated with OTA (0 up to 10 μg/mL), and cell viability (MTT assay), membrane stability (lactate dehydrogenase (LDH) release assay) and apoptotic cell rate (Tunel assay) were investigated. Further, the effect of the incubation with OTA has been evaluated at DNA level by the determination of DNA integrity, by the quantification of DNA adduct formation (8-hydroxy-2′-deoxyguanosine (8-OHdG)) and by the assessment of the global DNA methylation status (5-methyl-cytosine (5-mC)). The obtained results showed that after 24 h of OTA treatment, BME-UV1 cell viability was reduced in a dose-dependent way. OTA significantly (P?<?0.05) increased LDH release in BME-UV1 cells at all concentrations tested. OTA (1.25 μg/mL) induced 35 % LDH release in MDCK cells (P?<?0.05). A significant (P?<?0.05) change in percentages of apoptotic BME-UV1 (10?±?0.86) and MDCK (25?±?0.88) cells was calculated when the cells were co-incubated with OTA. The level of 8-OHdG adduct formation was significantly (P?<?0.05) increased in BME-UV1 cells treated with 1.25 μg/mL of OTA. The results of the present study suggest that a different mechanism of action may occur in these cell lines.

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Graphical abstract Study results overview

     

Further Characterization of 5-HT1A Receptors in the Goldfish Retina: Role of Cyclic AMP in the Regulation of the In Vitro Outgrowth of Retinal Explants

The presence of serotonin 5-HT_1A receptors and their physiological role were further characterized in the goldfish retina. The effects of the 5-HT_6/7 receptor antagonists pimozide, fluphenazine and amoxapine, the 5-HT_1A receptor antagonist WAY-100,135, and the alkylating agent N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, on the 5-HT_1A receptor agonist [³H]8-hydroxy-2-(di-n-propylamino)tetralin binding to retinal membranes, were evaluated. In addition, the effects of serotonin, 8-hydroxy-2-(di-n-propylamino)tetralin, WAY-100,135, the adenylate cyclase inhibitors SQ22536 and MDL12330A, and the cyclic AMP analog 8-bromoadenosine-3:5 cyclic monophosphate were also studied on neuritic outgrowth from retinal explants. WAY-100,135 but not 5-HT_6/7receptor antagonists inhibited [³H]8-hydroxy-2-(di-n-propylamino)tetralin binding to retinal membranes N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline decreased [³H]8-hydroxy-2-(di-n-propylamino)tetralin binding sites up to 70%, while receptor turnover was similar to that reported in other tissues. Serotonin and 8-hydroxy-2-(di-n-propylamino)tetralin stimulated cyclic AMP production, both ex vivo and in vitro, and these increases were related to inhibition of neuritic outgrowth. The inhibitory effect was reduced by SQ22536 and by WAY-100,135, and was mimicked by 8-bromoadenosine-3:5cyclic monophosphate. This study supports previous findings about the role of serotonin as a regulator of axonal outgrowth during in vitro regeneration of the goldfish retina and demonstrates that this effect is mediated, at least in part, by 5-HT_1A receptors through a mechanism which involves an increase of cyclic AMP levels.     

Photosynthetic acclimation to photon irradiance and its relation to chlorophyll fluorescence and carbon assimilation in the halotolerant green alga Dunaliella viridis

This work describes the long-term acclimation of the halotolerant microalga Dunaliella viridis to different photon irradiance, ranging from darkness to 1500 μmol m⁻² s⁻¹. In order to assess the effects of long-term photoinhibition, changes in oxygen production rate, pigment composition, xanthophyll cycle and in vivo chlorophyll fluorescence using the saturating pulse method were measured. Growth rate was maximal at intermediate irradiance (250 and 700 μmol m⁻² s⁻¹). The increase in growth irradiance from 700 to 1500 μmol m⁻² s⁻¹ did not lead to further significant changes in pigment composition or EPS, indicating saturation in the pigment response to high light. Changes in Photosystem II optimum quantum yield (F_v/F_m) evidenced photoinhibition at 700 and especially at 1500 μmol m⁻² s⁻¹. The relation between photosynthetic electron flow rate and photosyntetic O₂ evolution was linear for cultures in darkness shifting to curvilinear as growth irradiance increased, suggesting the interference of the energy dissipation processes in oxygen evolution. Carbon assimilation efficiencies were studied in relation to changes in growth rate, internal carbon and nitrogen composition, and organic carbon released to the external medium. All illuminated cultures showed a high capability to maintain a C:N ratio between 6 and 7. The percentage of organic carbon released to the external medium increased to its maximum under high irradiance (1500 μmol m⁻² s⁻¹). These results suggest that the release of organic carbon could act as a secondary dissipation process when the xanthophyll cycle is saturated. This revised version was published online in June 2006 with corrections to the Cover Date.     

High-level expression of the <Emphasis Type="Italic">Penicillium notatum</Emphasis> glucose oxidase gene in <Emphasis Type="Italic">Pichia pastoris</Emphasis> using codon optimization

The glucose oxidase (GOD) gene from Penicillium notatum was expressed in Pichia pastoris. The 1,815 bp gene, god-w, encodes 604 amino acids. Recombinant GOD-w had optimal activity at 35–40°C and pH 6.2 and was stable, from pH 3 to 7 maintaining >75% maximum activity after incubation at 50°C for 1 h. GOD-w worked as well as commercial GODs to improve bread making. To achieve high-level expression of recombinant GOD in P. pastoris, 272 nucleotides involving 228 residues were mutated, consistent with the codon bias of P. pastoris. The optimized recombinant GOD-m yielded 615 U ml⁻¹ (2.5 g protein l⁻¹) in a 3 l fermentor—410% higher than GOD-w (148 U ml⁻¹), and thus is a low-cost alternative for the bread baking industry.     

Genetic relatedness among some wild cherry (<Emphasis Type="Italic">Prunus</Emphasis> subgenus <Emphasis Type="Italic">Cerasus</Emphasis>) genotypes native to Iran assayed by morphological traits and random amplified polymorphic DNA analysis

Subgenus Cerasus species are useful genetic resources for cherry breeding programs. A total of 17 morphological traits together with 19 random amplified polymorphic DNA (RAPD) primers were used to study 39 accessions including 34 wild Cerasus subgenus genotypes belonging to Prunus avium L., P. cerasus L., P. mahaleb L., P. microcarpa Boiss., P. incana Pall., and P. brachypetala Boiss. species, along with an unknown wild Cerasus sample, two advanced cherry cultivars (‘Lambert’ and ‘Bulgar’), and two rootstocks (‘Colt’ and ‘Gisela 6’). Genotypes were separated into different groups according to their species and collection sites using cluster analysis performed by Ward’s clustering method based on morphological data. Nineteen RAPD primers from 60 screened produced 304 polymorphic reproducible bands (98.15% polymorphism). According to the similarity matrix, the lowest similarity was obtained between P. avium and P. microcarpa samples. A dendrogram was prepared by the unweighted pair-group method with arithmetic average (UPGMA), and the accessions were separated according to their species and geographic origin. In both morphological and molecular results, the advanced cultivars and rootstocks were separated from wild genotypes, and the unknown genotype was grouped with P. mahaleb accessions. Grouping by morphological characteristics was compared with the results of RAPD analysis, with no significant correlations between morphological and molecular data being found. This is the first report of molecular (RAPD) genetic diversity study in wild Cerasus subgenus genotypes from Iran, and the results demonstrate the high potential of RAPD analysis for discrimination of Cerasus subgenus genotypes.     

The complete mitochondrial genome analysis of the tiger (<Emphasis Type="Italic">Panthera tigris</Emphasis>)

The complete mitochondrial genomes of five tiger samples from three subspecies (P. t. sumatrae, P. t. altica, and P. t. tigris) were successfully obtained by using 26 specifically designed Panthera-specific primer sets. The genome organization and gene arrangement of the five tiger samples were similar to each other; however polymorphic tandem repeat sequences were observed in the control region (CR). This led to a difference in the genome lengths obtained from these five samples with an average size of 16,994 bp for the five tiger mitochondrial genomes. The nucleotide base composition was on average as follows: A, 31.8%; T, 27.0%; C, 26.6%; G, 14.6% and exhibited compositional asymmetry. Most of tiger mitochondrial genome characteristics are similar to those of other common vertebrate species; however, some distinctive features were observed in the CR. First, the repetitive sequence 2 (RS 2) contained two repeat units of 80 bp and the first 15 bp of what would be the third repeat motif. The repetitive sequence 3 (RS 3) contained 47–50 repeat motifs of a shorter 8 bp (ACGTAYAC)_n. Second, length heteroplasmy polycystosine (poly-C) stretches was observed at the end of the HV I locus in all tiger samples.     

Gliosis in the Mice Hippocampus Without Neuronal Death After Systemic Administration of High Dosage of Tetanus Toxin

Tetanus toxin (TeT), an exotoxin, has been studied to cause tetanus in mammalian brains, and it can block the release of some neurotransmitters and affect seizure propagation. In the present study, we investigated neuronal damage/death and glial changes in the mouse hippocampus after systemic administration (intraperitoneal injection) of TeT 10 and 100 ng/kg. In both the 10 and 100 ng/kg TeT-treated groups, no neuronal death occurred in any subregions of the mouse hippocampus until 24 h post-treatment; however, there were changes in glia in the hippocampus depending on time course and dosage. The morphology of GFAP-immunoreactive astrocytes and Iba-1-immunoreactive microglia was apparently changed in the 100 ng/kg TeT treated-group compared to the 10 ng/kg TeT treated-group. In the 100 ng/kg TeT treated-group, they were increased in size and their immunoreactivity was distinctively increased from 12 h post-treatment. We also found that their protein levels were increased in the hippocampus at 12 h post-treatment of 100 ng/kg TeT. In conclusion, these results indicate that the systemic administration of 100 ng/kg TeT induced a distinctive microglia changes in the mouse hippocampus without any neuronal death/damage.