Dark septate endophytic fungi associated with sugarcane plants cultivated in São Paulo, Brazil.

Dark septate endophytes (DSEs) constitute a polyphyletic group within the Ascomycota, with global distribution and a wide range of host plant species. The present study evaluated the diversity of DSE in sugarcane roots of the varieties RB867515, RB966928, and RB92579, and four varieties of not commercialized energy cane. A total of 16 DSE strains were isolated, mostly from the varieties RB966928 and RB867515, with six and five isolates, respectively. Just one of the four energy cane varieties had fungi with DSE appearance. The analyses of the DNA sequences from the internal transcribed spacer (ITS) and the large subunit (LSU), in association with the micromorphology of the isolates, allowed the differentiation of the 16 isolates in at least five species, within the families Periconiaceae, Pleosporaceae, Lentitheciaceae, Vibrisseaceae, and Apiosporaceae and the orders Pleosporales, Helotiales, and Xylariales. The order Pleosporales represented 80% of the isolates, and the species Periconia macrospinosa, with six isolates, accounted for the highest isolation frequency. The results confirm the natural occurrence of the DSE symbiosis in sugarcane varieties and the generalist character of these fungi as some of the detected species have already been reported associated with other host plants, ecosystems, and regions of the world

Arbuscular mycorrhizal fungi diversity in revegetated areas after bauxite mining.

Arbuscular mycorrhizal fungi (AMF) are obligatory biotrophs that have a symbiotic evolutionary relationship with about 80% of all terrestrial plant species. The fungus mainly supplies water and nutrients to the plant and receives photoassimilates. The AMF diversity affects both the competition among species and floristic composition of an area. Fluctuations in the population of this group of microorganisms can cause fluctuations in plant populations above ground. In this work, the AMF community profile in areas with different ages of revegetation was evaluated by morphological identification of spores and denaturing gradient gel electrophoresis (DGGE) techniques. We found 12 AMF species and dominance of the species Glomus macrocarpum determined by spore density. Since the richness level observed in each plot was low and there was predominance of one species of AMF, it can be concluded that these areas still present a high degree of disturbance. It was possible to detect complex band profiles by DGGE analyses for the two plant species studied, Visnia latifolia and Cecropia hololeuca. No relationship between AMF diversity and revegetation time was observed in these areas

Riqueza e frequência de espécies de fungos micorrízicos arbusculares em genótipos de amendoim forrageiro no Acre, Norte do Brasil.

O potencial da cultura do amendoim forrageiro associada aos fungos micorrízicos arbusculares (FMA) tem sido objeto de alguns estudos, porém a influência do genótipo sobre essa associação é pouco relatada. O objetivo deste trabalho foi determinar a densidade de esporos, riqueza de espécies, a frequência e ocorrência relativa de FMAs associados a genótipos de amendoim forrageiro. Foram coletadas amostras simples de solo de 45 genótipos pertencentes ao Banco Ativo de Germoplasma na Embrapa Acre. As amostras de solo foram coletadas a 5 cm de profundidade, com três repetições em delineamento inteiramente casualizado. As amostras de solo foram levadas para o Laboratório de Micorrizas da Embrapa Agrobiologia, para eterminação da densidade de esporos e identificação das espécies de FMAs. Foi realizada análise de variância e teste de Scott-Knott. Destacaram-se quatro genótipos de A. pintoi e dois híbridos interespecíficos, que apresentaram maior densidade de esporos. Foi verificada a ocorrência de 21 espécies de FMAs nas amostras de solo. A riqueza variou entre três e dez espécies. Três espécies de FMAs apresentaram elevada frequência relativa: Glomus macrocarpum (100,0%), Acaulospora tuberculata (97,8%) e Racocetra verrucosa (88,99%). Conclui-se, assim que: (i) Existe variabilidade genética entre os genótipos de amendoim forrageiro quanto à promoção da esporulação e riqueza de espécies de FMAs nas suas rizosferas; (ii) As espécies de FMAs Glomus macrocarpum, Acaulospora tuberculata, Racocetra verrucosa possuem alta presença na rizosfera dos genótipos de amendoim forrageiro, devendo serem estudadas visando sua introdução na cultura

In vivo and in vitro evidence that intrinsic upper- and lower-limb skeletal muscle function is unaffected by ageing and disuse in oldest-old humans

Aim: To parse out the impact of advanced ageing and disuse on skeletal muscle function, we utilized both in vivo and in vitro techniques to comprehensively assess upper- and lower-limb muscle contractile properties in 8 young (YG; 25 6 years) and 8 oldest-old mobile (OM; 87 5 years) and 8 immobile (OI; 88 4 years) women. Methods: In vivo, maximal voluntary contraction (MVC), electrically evoked resting twitch force (RT), and physiological cross-sectional area (PCSA) of the quadriceps and elbow flexors were assessed. Muscle biopsies of the vastus lateralis and biceps brachii facilitated the in vitro assessment of single fibre-specific tension (Po). Results: In vivo, compared to the young, both the OM and OI exhibited a more pronounced loss of MVC in the lower limb [OM (60%) and OI (75%)] than the upper limb (OM = 51%; OI = 47%). Taking into account the reduction in muscle PCSA (OM = 10%; OI = 18%), only evident in the lower limb, by calculating voluntary muscle-specific force, the lower limb of the OI (40%) was more compromised than the OM (13%). However, in vivo, RT in both upper and lower limbs (approx. 9.8 N m cm 2) and Po (approx. 123 mN mm 2), assessed in vitro, implies preserved intrinsic contractile function in all muscles of the oldest-old and were well correlated (r = 0.81). Conclusion: These findings suggest that in the oldest-old, neither advanced ageing nor disuse, per se, impacts intrinsic skeletal muscle function, as assessed in vitro. However, in vivo, muscle function is attenuated by age and exacerbated by disuse, implicating factors other than skeletal muscle, such as neuromuscular control, in this diminution of function. Keywords in vitro, in vivo, oldest-old, sarcopeni

Developing cardiac and skeletal muscle share fast-skeletal myosin heavy chain and cardiac troponin-I expression

Skeletal muscle derived stem cells (MDSCs) transplanted into injured myocardium can differentiate into fast skeletal muscle specific myosin heavy chain (sk-fMHC) and cardiac specific troponin-I (cTn-I) positive cells sustaining recipient myocardial function. We have recently found that MDSCs differentiate into a cardiomyocyte phenotype within a three-dimensional gel bioreactor. It is generally accepted that terminally differentiated myocardium or skeletal muscle only express cTn-I or sk-fMHC, respectively. Studies have shown the presence of non-cardiac muscle proteins in the developing myocardium or cardiac proteins in pathological skeletal muscle. In the current study, we tested the hypothesis that normal developing myocardium and skeletal muscle transiently share both sk-fMHC and cTn-I proteins. Immunohistochemistry, western blot, and RT-PCR analyses were carried out in embryonic day 13 (ED13) and 20 (ED20), neonatal day 0 (ND0) and 4 (ND4), postnatal day 10 (PND10), and 8 week-old adult female Lewis rat ventricular myocardium and gastrocnemius muscle. Confocal laser microscopy revealed that sk-fMHC was expressed as a typical striated muscle pattern within ED13 ventricular myocardium, and the striated sk-fMHC expression was lost by ND4 and became negative in adult myocardium. cTn-I was not expressed as a typical striated muscle pattern throughout the myocardium until PND10. Western blot and RT-PCR analyses revealed that gene and protein expression patterns of cardiac and skeletal muscle transcription factors and sk-fMHC within ventricular myocardium and skeletal muscle were similar at ED20, and the expression patterns became cardiac or skeletal muscle specific during postnatal development. These findings provide new insight into cardiac muscle development and highlight previously unknown common developmental features of cardiac and skeletal muscle. © 2012 Clause et al

Eficiência de fungos micorrízicos arbusculares (FMAs) em colonizar e beneficiar o crescimento de mudas micropropagadas de cará-da-costa.

Este trabalho foi conduzido na Embrapa Agrobiologia com o objetivo de avaliar a eficiência de espécies de FMAs quanto à capacidade de colonizar e promover o crescimento de mudas micropropagadas de cará-da-costa (Dioscorea cayenensis Lam). Estudaram-se quatro tratamentos: inoculação com três espécies de FMAs (Glomus clarum, Glomus etunicatum e Gigaspora margarita), e uma testemunha não inoculada (Ni). As plântulas inoculadas apresentaram maior colonização micorrízica que as Ni. G. etunicatum apresentou maior esporulação que as outras espécies e maior colonização que G. margarita. As partes aéreas apresentaram amarelecimento e secagem provavelmente pelo amadurecimento dos microtubérculos e término do ciclo da cultura. A maior secagem ocorreu em G. margarita sugerindo aceleração do amadurecimento. G. clarum e G. etunicatum foram mais eficientes em colonizar o cará-da-costa. Não houve efeito dos tratamentos no crescimento das plantas.Suplemento. Edição do 43 Congresso Brasileiro de Olericultura, Recife, jul. 2003

Impacto da retirada da palhada de áreas com cana-de-açúcar sobre os fungos micorrízicos arbusculares em solo de cerrado, em Dourados – MS.

FERTBIO 2010