Toxicity of the veterinary sulfonamide antibiotic sulfamonomethoxine to five aquatic organisms

The purpose of this study was to investigate the acute and chronic toxicity of sulfamonomethoxine (SMM) to aquatic organisms to evaluate its impact at different trophic levels in the ecosystem. Regarding the growth inhibition of microalgae, SMM exhibited 72-h median effective concentration (EC₅₀) values of 5.9 mg L⁻¹ for freshwater Chlorella vulgaris and 9.7 mg L⁻¹ for marine Isochrysis galbana. In a study on the cladocerans, SMM exhibited acute toxicity and 48-h median lethal concentrations of 48 mg L⁻¹ for Daphnia magna and 283 mg L⁻¹ for D. similis. An examination of chronic toxicity revealed that SMM inhibited the brook production of the cladocerans and exhibited 21-day EC₅₀ values of 14.9 mg L⁻¹ for D. magna and 41.9 mg L⁻¹ for D. similis. This study investigated the potentially adverse effects of SMM on aquatic organisms and revealed that microalgae exhibited higher sensitivity to SMM than cladocerans did. The residue of SMM in water is recommended to be carefully evaluated to reduce ecological impacts after applied to cultured animals.     

Evaluation of calcium supplementation with algae (Lithothamnion muelleri) on metabolic and inflammatory parameters in mice fed a high refined carbohydrate-containing diet

The aim of the present study was to evaluate the potential of calcium supplementation from Lithothamnium muelleri algae on metabolic and inflammatory parameters in mice with increased adiposity. Male mice were fed and divided during 8 weeks in: control (C), a high refined carbohydrate-containing diet (HC), HC diet supplemented with 1% of Lithothamnion muelleri algae (HC?+?A) and HC diet supplemented with 0.9% calcium carbonate (HC?+?C). Animals fed HC diet had increased body weight gain and adiposity, serum glucose and cholesterol, glucose intolerance and decreased insulin sensitivity, compared to control diet. However, the HC?+?A and HC?+?C groups did not prevent these aspects and were not able to change the CD14?+?cells population in adipose tissue of animals fed HC diet. Calcium supplementation with Lithothamnium muelleri algae and calcium carbonate had no protective effect against the development of adiposity, metabolic and inflammatory alterations induced by HC diet.     

Heparinoids algal and their anticoagulant, hemorrhagic activities and platelet aggregation

Polysaccharides extracted from brown marine algae represent a source of marine compounds with potential applications in medicine. Heparin-like compounds, fucoidans, have been proposed as alternatives to the anticoagulant heparin, which is prepared from mucous membrane of mammals. In this study, the activity of anticoagulant in activated partial thromboplastin time (APTT) and prothrombin time (PT) tests was assessed in the fucoidan (TF), from seaweed Fucus vesiculosus, partially desulfated fucoidans (PDF), desulfated fucoidans (DF) and purified fractions F1, F2 and F3 in acetone. Studies were also conducted to assess these polysaccharides for platelet aggregation and hemorrhagic activity. The APTT test showed high activity at 5 μg (≥240 s) for TF, F1 and F2 (P < 0.001). PT test showed high anticoagulant activity at 50 μg (≥120 s) for F1 (P < 0.001). Fraction F3, with low MW (15.2 kDa) and sulfate content (26.1%), had little effect in these two in vitro tests (P < 0.001). These compounds demonstrated a two-phase response to platelet aggregation at 50 μg/mL. However, at a concentration of 0.1 mg/mL, a hypoaggregate profile was observed for all fractions tested (P < 0.001). The analysis showed that fucoidans irreversibly induced platelet aggregation in high concentration. These polymers have low hemorrhagic effect when compared to heparin.     

Antioxidant,antimutagenic and antiproliferative activities in selected seaweed species from Sinaloa,Mexico

Context Seaweeds from the Mexican Pacific Ocean have not been evaluated as a source of chemoprotectants.

Objective The objective of this study is to evaluate chemopreventive activities of the seaweeds Phaephyceae – Padina durvillaei (Dictyotaceae) – Rodhophyceae – Spyridia filamentosa (Spyridiaceae), Gracilaria vermiculophylla (Gracilariaceae) – and Chlorophyceae – Ulva expansa (Ulvaceae), Codium isabelae (Codiaceae), Rhizoclonium riparium (Cladophoraceae) and Caulerpa sertularioides (Caulerpaceae).

Materials and methods Methanol, acetone and hexane seaweed extracts were assessed at 30 and 3?mg/mL on antioxidant capacity (DPPH and ABTS assays), 0.003–3.0?mg/plate on antimutagenic activity against AFB₁ using Salmonella typhimurium TA98 and TA100 tester strains in Ames test, and 12.5 to 100?μg/mL on antiproliferative activity on Murine B-cell lymphoma. Phenols, flavonoids and pigments content were also assessed as antioxidant compounds.

Results Extraction yield was higher in methanol than in acetone and hexane extracts (6.4, 2.7 and 1.4% dw). Antioxidant capacity was higher in brown and green than in red seaweed species, particularly in P. durvillaei extracted in acetone (EC_50? value=_?16.9 and 1.56?mg/mL for DPPH and ABTS). Flavonoids and chlorophylls were identified as mainly antioxidant components; particularly in hexane extracts, which were correlated with the antioxidant capacity. Highest mutagenesis inhibition (>?40%) occurred in R. riparium at the lowest concentration assayed (0.003?mg/plate), while highest antiproliferative inhibition (37 and 72% for 12.5 and 25?μg/mL) occurred in C. sertularioides.

Discussion and conclusion Flavonoids and chlorophylls explained the chemopreventive activities assessed in S. filamentosa, R. riparium and C. sertularioides. These seaweeds have a high potential as a source of novel chemoprotectants.     

Choloroplast DNA heterogeneity in Monodus sp. (Eustigmatophyta)

Summary Monodus satellite DNA, isolated by CsCl-Hoescht dye gradient centrifugation, was subjected to field inversion gel electrophoresis. Five differently sized DNA molecules were resolved. Molecules of 110 and 48 kb were identified as chloroplast DNA by hybridization analysis; a 40 kb molecular species is a degradation proluct, while the organellar origin of the 140 and 135 kb molecules remains unknown.     

Isolation and structure elucidation of halymeniaol,a new antimalarial sterol derivative from the red alga Halymenia floresii

A new mono-hydroxy acetylated sterol derivative: 12β-hydroxy-3β, 15α, 16β-triacetoxy-cholest-5-en-7-one (halymeniaol) (1), and cholesterol (2) were isolated from the marine red alga Halymenia floresii. The structure of the compound 1 (halymeniaol) was established from its spectral data, derived from HRMS/MS and 2D NMR. Compound 1 exhibited growth inhibitory activity against chloroquine-resistant Plasmodium falciparum 3D7 strain with an IC₅₀ of 3.0 μM.     

巢湖取水口浮游藻类污染调查

目的 了解合肥市以巢湖为水源的水厂取水口浮游藻类污染情况。方法 于1999年2、5、8、11月份（分别代表冬、春、夏、秋季）分别距以巢湖为水源的水厂岸边1.5km（A点）和3.0km（B点）水域采集水样进行藻类鉴定和计数。结果 以巢湖为水源的水厂取水口处水样检出浮游藻类83种,分属于8门49属;A点浮游藻种类多于B点。藻类计数年均值A点为7.024X108个/L,B点为8.205X108个/L。A、B两点水样藻类计数的变化趋势均为夏季>秋季>春季>冬季。藻类优势种为铜绿微囊藻、螺旋鱼腥藻和水华鱼腥藻。水样总氮、总磷、叶绿素α年均值分别为4.30mg/L、0.09mg/L和0.015mg/L,均超过我国暂行标准。结论 巢湖水源已严重富营养化。     

Effect of Glyphosate on Growth of Four Freshwater Species of Phytoplankton: A Microplate Bioassay

The acute toxicity of glyphosate herbicide was tested on the four species of freshwater phytoplankton, Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris and Chlorella saccharophila. Herbicide concentrations eliciting a 50% growth reduction over 72 h (EC₅₀) ranged from 24.5 to 41.7 mg L⁻¹, whilst a 10% growth inhibition is achieved by herbicide concentrations ranging from 1.6 to 3.0 mg L⁻¹, difficult to find neither in paddy fields (it is not used in rice) nor in the lake of the Albufera Natural Park. Chorella species are less sensitive to the herbicide than Scenedesmus species. It can be concluded that glyphosate has a low potential risk for the tested organisms.     

Distribution of naturally occurring quinones

Angiosperms, fungi (including lichens), and bacteria are the main sources of natural quinones. Small numbers are present in algae, ferns, conifers, sponges, echinoderms, other marine animals, and arthropods. In angiosperms quinones have some chemotaxonomic value at the genus and family level but more surveys are required.Based on a lecture given at the 16th LOF Symposium, 27 October 1989, Utrecht, the Netherlands.     

BLUE-GREEN ALGAE TOXINS AND LIVER CANCER

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