Effect of shading and nitrogen fertilization on nitrogen metabolism, essential oil content and antimicrobial activity of Achillea millefolium

The Achillea millefolium L. is a perennial herb with important antibacterial, antifungal, anti-inflammatory, antitumoral, and antioxidant properties. This research aimed to investigate the effect of shading (75%; black net) and nitrogen fertilization (0, 75 and 150 kg urea ha-1) on the nitrogen metabolism, essential oil yield and antimicrobial activity of A.millefolium at vegetative- and reproductive-stage. The evaluated parameters varied depending on the organ and the phenological stage of the plant considered. Overall, our findings indicated that shading decreased nitrogen assimilation. Decreased activities of nitrate reductase and glutamine synthetase were observed on shaded plants during reproductive and vegetative stages, respectively. Nitrate and total amino acid levels increased in shaded plants at the vegetative stage. Regarding nitrogen supply, the improved nitrogen metabolism and essential oil yield values were accompanied by intermediate concentrations of urea (75 kg ha-1). Plants fertilized with 75 kg urea ha-1 produced the highest amino acids concentration (vegetative stage), ammonium concentration (vegetative stage) and essential oil yield (reproductive stage). Shading or nitrogen supply did not influence the microbial activity of A. millefolium essential oil.However, the essential oil of leaves and flowers were highly effective against fungi and bacteria, especially gram-positive bacteria. In conclusion, the current study showed that full light and 75 kg urea ha-1 enhanced the nitrogen metabolism of A. millefolium in both vegetative and reproductive stages.

Phenotype-driven strategies for screening Candida parapsilosis complex for molecular identification

Abstract In this study, phenotypic methods presented >80% agreement with the molecular identification of 59 Candida parapsilosis complex. Growth at 15% NaCl or pH 7.0 significantly reduced cfu-counts of Candida orthopsilosis, suggesting these conditions may support the development of phenotypic methods for the differentiation of the cryptic species of C. parapsilosis complex.

Phenotype-driven strategies for screening Candida parapsilosis complex for molecular identification

Abstract In this study, phenotypic methods presented >80% agreement with the molecular identification of 59 Candida parapsilosis complex. Growth at 15% NaCl or pH 7.0 significantly reduced cfu-counts of Candida orthopsilosis, suggesting these conditions may support the development of phenotypic methods for the differentiation of the cryptic species of C. parapsilosis complex.

In vitro study on the antimicrobial effect of hydroalcoholic extracts from Mentha arvensis L. (Lamiaceae) against oral pathogens - doi: 10.4025/actascibiolsci.v34i4.8959

In vitro tests could be a valuable tool for the evaluation of medicinal plants antimicrobial activity. Mentha arvensis of the Lamiaceae family is one of the most frequently traditional plants used in Brazil. Hydroalcoholic extracts of M. arvensis were analyzed for antimicrobial activity on Streptococcus mutans, Streptococcus sobrinus and Candida albicans. Three different assays (agar diffusion, broth macro- and micro-dilution methods) were used to evaluate antimicrobial activity. Although hydroalcoholic extracts of M. arvensis did not show any antibacterial effect, its antifungal activity against C. albicans was revealed. According to the micro-dilution broth assay, MIC of the hydroalcoholic extract from leaves of M. arvensis on Candida albicans strains ranged between 625 and 2500 mg mL-1. Results suggest that M. arvensis hydroalcoholic extract may be considered a potentially antifungal agent against C. albicans, and a possible item for human antibiotic therapy.  However, further biological tests on the plants efficacy and side-effects are necessary before its use on humans.

In vitro study on the antimicrobial effect of hydroalcoholic extracts from Mentha arvensis L. (Lamiaceae) against oral pathogens / Estudo in vitro do efeito antimicrobiano dos extratos hidroalcólicos de Mentha arvensis L. (Lamiaceae) contra patógenos orais

In vitro tests could be a valuable tool for the evaluation of medicinal plants' antimicrobial activity. Mentha arvensis of the Lamiaceae family is one of the most frequently traditional plants used in Brazil. Hydroalcoholic extracts of M. arvensis were analyzed for antimicrobial activity on Streptococcus mutans, Streptococcus sobrinus and Candida albicans. Three different assays (agar diffusion, broth macro- and micro-dilution methods) were used to evaluate antimicrobial activity. Although hydroalcoholic extracts of M. arvensis did not show any antibacterial effect, its antifungal activity against C. albicans was revealed. According to the micro-dilution broth assay, MIC of the hydroalcoholic extract from leaves of M. arvensis on Candida albicans strains ranged between 625 and 2500 µg mL-1. Results suggest that M. arvensis hydroalcoholic extract may be considered a potentially antifungal agent against C. albicans, and a possible item for human antibiotic therapy. However, further biological tests on the plant's efficacy and side-effects are necessary before its use on humans.

Testes in vitro podem ser uma ferramenta valiosa para a avaliação da atividade antimicrobiana de plantas medicinais. Mentha arvensis é uma das plantas medicinais brasileiras mais frequentemente utilizadas e pertence à família Lamiaceae. No presente estudo, extratos hidroalcólicos de M. arvensis foram analisados quanto à sua atividade antimicrobiana sobre Streptococcus mutans, Streptococcus sobrinus e Candida albicans. Três diferentes ensaios (métodos de difusão em ágar, macro e microdiluição em caldo) foram utilizados para avaliação da atividade antimicrobiana. Embora os extratos hidroalcólicos de M. arvensis não demonstraram qualquer efeito antibacteriano, eles apresentaram atividade antifúngica contra C. albicans. Baseado no ensaio de microdiluição em caldo, a CIM do extrato hidroalcólico das folhas de M. arvensis sobre cepas de C. albicans variaram de 625 a 2500 µg mL-1. Estes achados sugerem que o extrato hidroalcólico de M. arvensis pode ser considerado um agente antifúngico em potencial contra C. albicans, e um possível candidato para antibioticoterapia humana. Contudo, mais testes biológicos sobre a eficácia e efeitos adversos desta planta são necessários antes do seu uso em humanos.

Species distribution and in vitro fluconazole susceptibility of clinical Candida isolates in a Brazilian tertiary-care hospital over a 3-year period / Distribuição de espécies e suscetibilidade in vitro ao fluconazol de isolados clínicos de Candida em um hospital terciário brasileiro num período de três anos

INTRODUCTION: In this study, we aimed at identifying Candida isolates obtained from blood, urine, tracheal secretion, and nail/skin lesions from cases attended at the Hospital Universitário de Londrina over a 3-year period and at evaluating fluconazole susceptibilities of the isolates. METHODS: Candida isolates were identified by polymerase chain reaction (PCR) using species-specific forward primers. The in vitro fluconazole susceptibility test was performed according to EUCAST-AFST reference procedure. RESULTS: Isolates were obtained from urine (53.4 percent), blood cultures (19.2 percent), tracheal secretion (17.8 percent), and nail/skin lesions (9.6 percent). When urine samples were considered, prevalence was similar in women (45.5 percent) and in men (54.5 percent) and was high in the age group >61 years than that in younger ones. For blood samples, prevalence was high in neonates (35 percent) and advanced ages (22.5 percent). For nail and skin samples, prevalence was higher in women (71.4 percent) than in men (28.6 percent). Candida albicans was the most frequently isolated in the hospital, but Candida species other than C. albicans accounted for 64 percent of isolates, including predominantly Candida tropicalis (33.2 percent) and Candida parapsilosis (19.2 percent). The trend for non-albicans Candida as the predominant species was noted from all clinical specimens, except from urine samples. All Candida isolates were considered susceptible in vitro to fluconazole with the exception of isolates belonging to the intrinsically less-susceptible species C. glabrata. CONCLUSIONS: Non-albicans Candida species were more frequently isolated in the hospital. Fluconazole resistance was a rare finding in our study.

INTRODUÇÃO: Neste estudo objetivamos a identificação de isolados de Candida obtidos de sangue, urina, secreção traqueal e de lesões de unha/pele, de casos atendidos no Hospital Universitário de Londrina num período de três anos. Avaliamos também a suscetibilidade dos isolados ao fluconazol. MÉTODOS: Os isolados de Candida foram identificados pela reação em cadeia da polimerase (RCP) usando oligonucleotídeos iniciadores espécie-específicos. O teste de suscetibilidade in vitro ao fluconazol foi realizado segundo o procedimento de referência EUCAST-AFST. RESULTADOS: Isolados foram obtidos de urina (53,4 por cento), sangue (19,2 por cento), secreção traqueal (17,8 por cento) e lesões de unha/pele (9,6 por cento). Considerando as amostras de urina, a prevalência foi similar em mulheres (45,5 por cento) e em homens (54,5 por cento) e foi alta no grupo de idade > 61 anos do que em grupos mais jovens. Para amostras de sangue a prevalência foi alta em neonatos (35 por cento) e idades avançadas (22,5 por cento). Para amostras de unha e pele a prevalência foi maior em mulheres (71,4 por cento) do que em homens (28,6 por cento). Candida albicans foi a mais frequentemente isolada no hospital, mas outras espécies de Candida corresponderam a 64 por cento dos isolados, incluindo predominantemente Candida tropicalis (33,2 por cento) e Candida parapsilosis (19,2 por cento). A tendência de Candida não-albicans como espécie predominante foi observada para todas as amostras clínicas, exceto para amostras de urina. Todos isolados de Candida foram considerados suscetíveis, in vitro, ao fluconazol com exceção dos isolados pertencentes às espécies intrinsecamente menos suscetíveis C. glabrata. CONCLUSÕES: Espécies de Candida não-albicans foram mais frequentemente isoladas no hospital. Resistência ao fluconazol foi rara no nosso estudo.

Crescimento e produção de pigmentos fotossintéticos em Achillea millefolium L. cultivada sob diferentes níveis de sombreamento e doses de nitrogênio / Growth and production of photosynthetic pigments in Achillea millefolium L. grown under different levels of shading and nitrogen

A espécie Achillea millefolium L., conhecida como mil-folhas, é uma planta herbácea, rizomatosa e perene. Sua importância medicinal deve-se às suas atividades antibacterianas, antiinflamatórias, antitumorais, analgésicas e antioxidantes. O efeito da disponibilidade de luz e do nitrogênio sobre o crescimento e produção dessa espécie é pouco conhecido. O objetivo deste trabalho foi avaliar a resposta de A. millefolium L., cultivada sob diferentes níveis de sombreamento e doses de nitrogênio, quanto ao crescimento e à produção de pigmentos fotossintéticos. As plantas foram cultivadas sob três doses de nitrogênio (0, 75 e 150kg uréia ha-1) e submetidas a dois níveis de sombreamento 0 por cento (luz plena) e 75 por cento (sombrite 75 por cento). Adotou-se o delineamento experimental de blocos casualizados com quatro repetições em um fatorial 3x2 (doses de nitrogênio x níveis de sombreamento). O sombreamento influenciou a maioria dos caracteres avaliados, causando uma redução significativa no acúmulo de massa seca da parte aérea (caule + folha + flor), caule, folhas e flores e aumento nos teores de clorofila a, b, total e carotenóides. Os resultados sugerem que a espécie A. millefolium L. possui adaptação à baixa intensidade luminosa, devido às alterações nas características foliares, relacionadas aos teores de pigmentos fotossintéticos.

Achillea millefolium L., known as yarrow, is an herbaceous, rhizomatous and perennial plant. Its medicinal importance is attributed to antibacterial, anti-inflammatory, antitumoral, analgesical and antioxidant activities. The effect of light availability and nitrogen on growth and production of this species is little known. The objective of this study was to evaluate the growth and production of photosynthetic pigments in A. millefolium L. grown under different levels of shading and nitrogen levels. Plants were cultivated under three nitrogen levels (0, 75 and 150kg urea ha-1) and subjected to two levels of shading 0 percent (full light) and 75 percent (75 percent black). The experimental design was delineated in randomized blocks with four replicates in a factorial 3 x 2 (nitrogen levels x levels of shading). The shading influenced most parameters evaluated, causing a significant reduction in dry mass accumulation of shoot (stem + leave + flower), stem, leaves and flowers and increase in levels of chlorophyll a, b, total and carotenoids. Results suggest that Achillea millefolium L. has adaptated to low light intensity, due to changes in leaf traits related to photosynthetic pigments content.