Guanitoxin (GNT) is a natural organophosphate produced by some species of freshwater cyanobacteria, which inhibits the active site of acetylcholinesterase, preventing the hydrolysis of cholinesterases and consequently causing serious disturbances in the neuromuscular system. Despite having a chemical structure like synthetic organophosphates, there is still no analytical standard available for environmental and freshwater monitoring. Therefore, this study investigated the stability of GNT under different storage conditions, pH, and temperature. The toxin is produced by the cyanobacterium Sphaerospermopsis torques-reginae and monitored by liquid chromatography coupled to mass spectrometry (LC-MS) and LC-MS/MS for the identification and verification of its stability. The main degradation product formed is the hydroxy-amino-guanidinic derivative of the toxin. The results also indicate that GNT is stable in acidic medium (pH = 3.0), but can gradually degrade at room temperature (> 23 ºC) over a period of 96 h. Lyophilized biomass of S. torques-reginae containing GNT remained stable when stored in a refrigerator below 4 ºC. In addition, the extraction yield is higher when prepared from fresh S. torques-reginae cells than from lyophilized material. Thus, the results shown here contribute with valuable information for studies that aim at the isolation, identification, and monitoring of GNT in samples of raw water and cyanobacterial blooms.

Cyanobacteria produce a wide variety of bioactive compounds, making them a highly promising group in the search for novel molecules with pharmacological and biotechnological properties. Among these, microginins attract attention for being peptides which inhibit angiotensin-converting enzyme, turning them into potential targets for hypertension and congestive heart failure treatment. This work describes a rapid and sensitive method for untarget screening of microginins in cyanobacteria extracts by LC-QqQ-MS/MS. These compounds are mostly characterized by containing 3-amino-2-hydroxy-decanoic acid at the N-terminus, which often could be chlorinated, dichlorinated or methylated. Based on the fragment ion arising from this decanoic acid derivative, a precursor ion scan (PIS) strategy has been proposed. This approach identified suspect microginins in cyanobacterial strains and environmental samples that were later confirmed by LC-QTOF-MS/MS. Eight new microginins structures were characterized based on the obtained fragmentation spectra from a total of 19 variants detected. This study highlights the applicability of PIS mode acquisition for untarget screening, detecting a wide variety of microginins with amino acids modifications, produced mainly by Microcystis aeruginosa strains. This method is a useful tool for the identification and environmental monitoring of molecules with conserved molecular substructures that possess similar fragmentation pattern

Resumo: O artigo investiga as estratégias bem-sucedidas, mobilizadas pelos alunos do ciclo de alfabetização ao resolverem problemas de proporção simples. Solicitou-se a 483 alunos do 1º ao 3º ano que resolvessem seis problemas de proporção, sendo analisadas as respostas de 182 alunos que tiveram estratégias bem-sucedidas. Quando comparados os anos escolares, há aumento nos acertos de ano para ano, na classe de situações um para muitos, o que não se pode afirmar sobre a classe muito para muitos, que permaneceu estagnada. Pelos resultados obtidos, é possível que a estrutura multiplicativa esteja sendo pouco discutida, nos três primeiros anos do Ensino Fundamental.

Abstract: The article investigates the successful strategies mobilized by students in the literacy cycle when solving problems of simple proportion. 483 students from the 1st to the 3rd grade of Brazilian Elementary Education, were asked to solve six problems of proportion, and the responses of 182 students who had successful strategies were analyzed. When comparing school grades, there is an increase in hits from year to year, in the class of situations one-to-many, which cannot be said about the class for many, which remained stagnant. From the results obtained, it is possible that the multiplicative structure is being little discussed in the first three grades of elementary school.

Cyanobacteria are prokaryotic and photosynthetic organisms, which can produce a wide range of bioactive compounds with different properties; including a variety of toxic compounds, also known as cyanotoxins. In this work, we describe the isolation of seven cyanobacterial strains from two reservoirs in São Paulo State, Brazil. Seven different chemical variants of microcystins (MC-RR, MC-LR, MC-YR, MC-LF, MC-LW, and two demethylated variants, dm-MC-RR and dm-MC-LR) were detected in three of the ten isolated strains. One particular Microcystis aeruginosa strain (LTPNA 02) was chosen to evaluate its growth by cell count, and its toxin production under seven different nutritional regimes. We observed different growth behaviors in the logarithmic growth period for only three experiments (p <0.05). The total growth analysis identified four experiments as different from the control (p < 0.01). Three microcystin variants (MC-RR, MC-LR and MC-YR) were quantified by liquid chromatography-tandem mass spectrometry. At the experimental end, the toxin content was unchanged when comparing cell growth in ASM-1 (N:P = 1), MLA and BG-11 (N:P = 10) medium. In all other experiments, the lowest microcystin production was observed from cells grown in Bold 3N medium during the exponential growth phase. The highest microcystin content was observed in cultures using BG-11(N:P = 100) medium.

O objetivo deste trabalho foi avaliar as respostas das células de Haematococcus pluvialis ao processo de indução à carotenogênese, sob estresse luminoso e nutricional. As células foram aclimatadas durante 15 dias em meio WC, com aeração com ar atmosférico sintético filtrado e fluxo de 100 mL min-1, intensidade luminosa de 50 µmol fótons m-2 s-1, fotoperíodo de 12 horas e temperatura de 23ºC. Foram comparados dois tratamentos: cultivo nas condições descritas, mas com aumento da intensidade luminosa para 350 µmol fótons m-2 s-1 ; e cultivo nas mesmas condições do tratamento anterior, mas com aeração contendo 4% de CO2. Os tratamentos foram conduzidos em triplicata, durante dez dias. Com a adição de CO2 e o incremento da iluminação, observou-se aumento da razão carotenoides/clorofila e da biomassa celular. As células cessaram a divisão no segundo dia de estresse, quando o nitrato se tornou limitante, e aumentaram significativamente seu biovolume. A excreção de carbono orgânico e a concentração de astaxantina aumentam em resposta à adição de CO2. O estresse por intensidade luminosa, aliado à adição de CO2, otimiza a carotenogênese em H. pluvialis e aumenta a produção de astaxantina.

The objective of this work was to evaluate the responses of Haematococcus pluvialis cells to the carotenogenesis induction process, under light and nutrition stress. Cells were acclimated during 15 days in WC medium, with aeration with synthetic, filtered atmospheric air and flow rate of 100 mL min-1, light intensity of 50 µmol photons m-2 s-1, photoperiod of 12 hours, and temperature of 23ºC. The following two treatments were compared: cultivation under the described conditions, but with increase of light intensity up to 350 µmol photons m-2 s-1 ; and cultivation under the same conditions as the previous treatment, but with aeration containing 4% CO2. The treatments were done in triplicate, during ten days. With the addition of CO2 and the increment in lighting, an increase was observed in the carotenoids/chlorophyll ratio and cell biomass. Cells stopped dividing on the second day of stress, when nitrate became limiting, and significantly increased their biovolume. The excretion of organic carbon and the concentration of astaxanthin increase in response to the addition of CO2. Stress by light intensity combined with CO2 addition optimizes carotenogenesis in H. pluvialis and increases astaxanthin production.

Mulher, 33 anos, apresenta quadro de alopecia progressiva do couro cabeludo há 3 anos. Tratamento com hidroxicloroquina há 12 meses, sem apresentar melhora. Ao exame físico exibe múltiplas áreas de alopecia cicatricial no couro cabeludo, além de hipotricose axilar e pubiana. A dermatoscopia evidencia hipercetose folicular e acentuação dos óstios foliculares. O exame anatomopatológico revela diminuição do número de folículos pilosos, infiltrado perifolicular e fibrose. A síndrome de Graham-Little Piccardi Lassueur é uma dermatose rara, caracterizada pela tríade de alopecia cicatricial multifocal do couro cabeludo, ceratose folicular disseminada e hipotricose das regiões axilares e pubianas. A terapêutica desta dermatose é um desafio, muitas medicações relatadas tem resultados controversos. Relatamos o caso desta síndrome rara que apresentou melhora com corticoterapia.

A 33-year-old woman presented with a 3-year history of progressive alopecia of the scalp. Past treatment with hydroxicloroquine did not show improvement. Physical examination revealed multiple areas of alopecia with atrophic aspect of the scalp, and axillary and pubic hypotrichosis. Dermoscopy showed hyperkeratosis and accentuation of follicular ostia. Anatomopathological examination revealed decrease in the number of hair follicles, upper perifollicular infiltrate and areas with fibrosis. The Piccardi-Lassueur-Graham-Little syndrome is a rare disorder, characterized by the triad of multifocal scarring alopecia of the scalp, keratotic follicular eruption and hypotrichosis of axillary and pubic regions. Management is a challenge and many medications tried have controversial results. We report a case of this rare syndrome which improved with corticoids.

This work presents the effects of an anatoxin-a(s)-containing extract on a cockroach semi-isolated heart preparation and the results supporting the extract’s biological activity on acetylcholinesterase (purified from ell). The presence of the toxin in cyanobacterial strains Anabaena spiroides (ITEP-024, ITEP-025 and ITEP-026) isolated from the Tapacurá reservoir in Pernambuco, Brazil, was confirmed by means of liquid chromatography coupled to an ion-trap mass spectrometer. The anticholinesterase activity was assessed biochemically by the Ellman test and was confirmed by measuring the cockroach’s heart rate. The concentration of the extract containing the tested anatoxin-a(s) (antx-a(s)) (10, 16 and 100 μg.μL-1) inhibited the eel acetylcholinesterase (AChE) by more than 90%. The cockroach cardiac frequency increased by a maximum of about 20% within 29 min after the addition of 2.5x10³ μg of extract containing antxa (s).g-1 bw (n=9, p<0.05). Our results strongly indicate that antx-a(s) is capable of exerting biological effects on cockroach, indicating that more research might be conducted to determine its role in the environment, especially on insects.

In this study we report the characterization of the volatile compounds of Laurencia dendroidea. Solvent extracts (dichloromethane and methanol), hydrodistillation extracts and headspace solid-phase microextraction samples were obtained and analyzed by GC-MS. Forty-six volatile components were identified in L. dendroidea, among them hydrocarbons, alcohols, phenols, aldehydes, ketones, acids, esters and terpenes.

Gracilaria domingensis (Kützing) Sonder ex Dickie and Gracilaria birdiae (Plastino & Oliveira) (Gracilariales, Rhodophyta) are seaweeds that occur on the Brazilian coast. Based on their economic and pharmaceutical importance, we investigated the antioxidant activity of the methanolic, ethyl acetate and hexane extracts of both species. The hexane extracts display a high antioxidant activity and comparative analyses indicated G. birdiae as the most active species. Chemical investigation of these fractions showed several carotenoids and fatty acids, as well as cholesterol and sitosterol derivatives. HPLC-DAD analysis of G. birdiae showed violaxanthin (0.04 μg.mg-1 of dry material), antheraxanthin (5.31 μg.mg-1), aloxanthin (0.09 μg.mg-1), zeaxanthin (0.45 μg.mg-1) and β-carotene (0.37 μg.mg-1) as the major carotenoids. G. domingensis showed a similar carotenoid profile, however, with much lower concentration than G. birdiae. Gas chromatography coupled to mass spectrometry was used to determine other nonpolar compounds of these seaweeds. The main compounds detected in both studied species were the fatty acids 16:0; 18:1 Δ9; 20:3 Δ6,9,12, 20:4 Δ5,8,11,14. We found no specificity of compounds in either species. However, G. birdiae, presented higher contents of carotenoids and arachidonic acid than G. domingensis.

INTRODUÇÃO: A perda da superfície dos dentes ou lesão não cariosa, é um processo fisiológico que ocorre com o decorrer do envelhecimento, mas pode ser considerado patológico quando o grau de destruição cria problemas funcionais, estéticos ou de sensibilidade dentária. Diversos fatores podem contribuir em parte, mas não necessariamente simultânea ou igualmente como causa das lesões não cariosas. Apesar dos casos de desgaste (atrição, abrasão, erosão, abfração) ser comumente discutidos como alterações independentes, na maioria das vezes a perda da superfície dos dentes é resultado de uma combinação de fatores. Um dos grandes desafios é identificar ou quantificar a influência de fatores como o consumo excessivo e abusivo de drogas e substâncias ácidas, fatores ambientais e agentes etiológicos intrínsecos como o refluxo gastresofágico. O tratamento imediato deve ser direcionado para a resolução da sensibilidade e da dor, entretanto, a investigação da causa é primordial. OBJETIVO: O objetivo deste trabalho é, através de uma revisão da literatura, auxiliar as diversas especialidades médicas a identificar corretamente os fatores etiológicos das lesões não cariosas.

INTRODUCTION: The loss of the teeth surface or not carious lesion, is a physiological process that occur during the aging, but can be considered as pathological when the degree of destruction creates functional problems, aesthetic or dental sensibility. Many factors can contribute in part, but not necessarily simultaneously or equally as the cause of the not carious lesions. Although the cases of attrition (attrition, abrasion, corrosion and abfraction) are commonly discussed as independent alterations, in most of the times the loss of the teeth surface is the result of a combination of factors. One of the greatest challenges is to identify or quantify the influence of factors like the excessive consumption and abusive of drugs and acid substances, environmental factors and intrinsic etiologic agents such as gastro esophageal reflux. The immediate treatment must be directed for the resolution of sensibility and from pain; however, the investigation of the cause is essential. OBJECTIVE: The objective of this work is, through the literature review; help the many medical specialties to identify correctly the etiologic factors of not carious lesions.

A batata-semente (Solanum tuberosum) é considerada fator fundamental para garantir alta produtividade, qualidade de tubérculos e uma boa safra. O presente trabalho foi conduzido na Universidade José do Rosário Vellano (UNIFENAS), Alfenas-MG de setembro de 2007 a setembro de 2008 em três etapas distintas e sequenciais. Objetivou-se estudar o efeito da aplicação de reguladores de crescimento em brotos destacados de batata-semente na produção de minitubérculos; na brotação de minitubérculos e na produção comercial originada dos minitubérculos. Foram utilizados brotos de batata destacados de batata-semente (livre de vírus), da cultivar Bintje, originada de importação experimental do Alasca, com dois tamanhos: broto grande (média de 25 cm) e broto pequeno (média de 13 cm) e reguladores de crescimento AIB, GA3, BAP e 2,4D. O delineamento experimental para todos os trabalhos foi de blocos ao acaso em esquema fatorial 5 x 2 com três repetições. O número de minitubérculos produzido na primeira etapa originados de brotos grandes variou significativamente de 3,1 (GA3) a 7,7 (AIB) e de 2,3 (AIB) a 7,9 (controle) quando originados de brotos pequenos, enquanto que o peso variou de 7,5 g (GA3) a 10,6 g (AIB), empregando-se brotos grandes e de 2,7 (BAP) a 12,3 g (controle), com o uso de brotos pequenos. Os minitubérculos não apresentaram diferenças significativas para o tempo de brotação o que ocorreu num espaço de sete a oito dias. A produção comercial originada dos minitubérculos variou significativamente de 12,6 (GA3) a 29,5 t ha-1 (AIB), quando se avaliou brotos grandes e de 22,1 (BAP) a 30,4 t ha-1 (controle), com o uso de brotos pequenos. Conclui-se que os brotos de batata-semente, cultivar Bintje, podem ser usados para a produção de tubérculos-semente e não devem ser tratados com os reguladores de crescimento. Brotos menores destacados de batata-semente, cv. Bintje sem tratamento, devem ser preferidos para a produção de minitubérculos semente.

The seed potatoes (Solanum tuberosum) are considered a key factor to ensure high productivity, quality of the tuber and a good harvest. This study was carried out at the University José Rosário Vellano (UNIFENAS), Alfenas, Minas Gerais state, Brazil, from September 2007 until September 2008 in three distinct and sequential stages. The objective was to study the effect of growth regulators applied on: (1) sprouts detached from seed-potato tubers on minituber yield, (2) sprouting minituber and (3) marketable yield originated from minitubers. Potato sprouts used were detached from seed potatoes tubers (virus free), cultivar Bintje, originated from an experimental import of sprouts from Alaska (USA), with two sizes: large sprouts (average of 25 cm) and small sprouts (average of 13 cm) and growth regulators IBA, GA3, BAP and 2,4D. The experimental design for all experiments was of randomized blocks in a factorial scheme 5x2 with three replications. The number of minitubers produced in the first stage originated from large sprouts varied significantly from 3.1 (GA3) to 7.7 (IBA) and 2.3 (IBA) to 7.9 (control), small prouts, while the weight varied from 7.5 g (GA3) to 10.6 g (IBA), large sprouts and 3.4 g (IBA) to 12.3 g (control), small sprouts. The minitubers did not show significant differences for the time of shooting which occurred within seven to eight days. Marketable production originated from minitubers varied significantly from 12.06 t ha-1 (GA3) to 29.51 t ha-1 (AIB), large sprouts and 22.11 t ha-1 (BAP) to 30.35 t ha-1 (control), small sprout. Sprouts from seed-potato tubers cv Bintje, can be used for seed tuber production and should not be treated with growth regulators. Small sprouts, detached from seed potatoes, cultivar Bintje, without treatment, should be preferred for the production of seed-potato minitubers.

In this work we described the cultivation of Chlorella vulgaris in a photobioreactor to algal biomass production. The dried biomass was used as feedstock for biodiesel production, it presented 26% lipids and via sonocatalysis stage of the methodology resulted in 60% of fatty acid methyl esters (FAME). The FAME content was confirmed by Gas Chromatography (GC).

Qualitative and quantitative studies of mycosporine-like amino acids (MAAs) in three species of the genus Gracilaria Greville (G. birdiae, G. domingensis and G. tenuistipitata) were performed. A simple and efficient extraction procedure based on ethanol was described. HPLC, UV and mass spectrometry experiments revealed different profiles between extracts obtained from one species cultivated in the laboratory (G. tenuistipitata) and two species collected in their natural environment (G. birdiae and G. domingensis). The levels detected in the latter two species were approximately 150 times higher than in the species cultivated in vitro. This study revealed that G. birdiae and G. domingensis present a potential source for economical exploration of MAAs.

Two known sesquiterpenes (1R*,2S*,3R*,5S*,8S*,9R*)-2,3,5,9-tetramethyltricyclo[6.3.0.0(1,5)]undecan-2-ol and (1S*,2S*,3S*,5S*,8S*,9S*)-2,3,5,9-tetramethyltricyclo-[6.3.0.0(1,5)]undecan-2-ol were isolated for the first time from the essential oil of the red seaweed Laurencia dendroidea collected in the Brazilian coast. These compounds were not active against eight bacteria strains and the yeast Candida albicans, but showed some antioxidant activity. Both compounds were also found in other seaweed species showing that they are not exclusive taxonomic markers to the genus Laurencia.