Range-wide neutral and adaptive genetic structure of an endemic herb from Amazonian Savannas.

Conserving genetic diversity in rare and narrowly distributed endemic species is essential to maintain their evolutionary potential and minimize extinction risk under future environmental change. In this study we assess neutral and adaptive genetic structure and genetic diversity in Brasilianthus carajensis (Melastomataceae), an endemic herb from Amazonian Savannas. Using RAD sequencing we identified a total of 9365 SNPs in 150 individuals collected across the species' entire distribution range. Relying on assumption-free genetic clustering methods and environmental association tests we then compared neutral with adaptive genetic structure. We found three neutral and six adaptive genetic clusters, which could be considered management units (MU) and adaptive units (AU), respectively. Pairwise genetic differentiation (F ST) ranged between 0.024 and 0.048, and even though effective population sizes were below 100, no significant inbreeding was found in any inferred cluster. Nearly 10 % of all analysed sequences contained loci associated with temperature and precipitation, from which only 25 sequences contained annotated proteins, with some of them being very relevant for physiological processes in plants. Our findings provide a detailed insight into genetic diversity, neutral and adaptive genetic structure in a rare endemic herb, which can help guide conservation and management actions to avoid the loss of unique genetic variation.

Correction for Ichiwaki et al., "Genome Sequence of Micromonospora sp. NBS 11-29, an Antibiotic and Hydrolytic Enzyme Producer, Isolated from River Sediment in Brazil".

[This corrects the article DOI: 10.1128/genomeA.00552-17.].

Influence of water quality on diversity and composition of fungal communities in a tropical river.

Freshwater fungi are key decomposers of organic material and play important roles in nutrient cycling, bio-remediation and ecosystem functioning. Although aquatic fungal communities respond to pollution, few studies have quantitatively assessed the effect of freshwater contamination on fungal diversity and composition; and knowledge is scarcer for tropical systems. Here we help fill this knowledge gap by studying a heavily-contaminated South American river spanning a biodiversity hotspot. We collected 30 water samples scattered across a quality gradient over two seasons and analyzed them using Terminal Restriction Fragment Length Polymorphisms (T-RFLP) coupled with 454 Pyrosequencing. Using T-RFLP we identified 451 and 442 Operational Taxonomy Units (OTUs) in the dry and rainy seasons respectively, whereas Pyrosequencing revealed 48,553 OTUs from which 11% were shared between seasons. Although 68% of all identified OTUs and 51% of all identified phyla remained unidentified, dominant fungal phyla included the Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota, Zygomycota and Neocallimastigomycota, while Calcarisporiella, Didymosphaeria, Mycosphaerella (Ascomycota) and Rhodotorula (Basidiomycota) were the most abundant genera. Fungal diversity was affected by pH and dissolved iron, while community composition was influenced by dissolved oxygen, pH, nitrate, biological oxygen demand, total aluminum, total organic carbon, total iron and seasonality. The presence of potentially pathogenic species was associated with high pH. Furthermore, geographic distance was positively associated with community dissimilarity, suggesting that local conditions allowed divergence among fungal communities. Overall, our findings raise potential concerns for human health and the functioning of tropical river ecosystems and they call for improved water sanitation systems.

Genome Sequence of Micromonospora sp. NBS 11-29, an Antibiotic and Hydrolytic Enzyme Producer, Isolated from River Sediment in Brazil.

The genus Micromonospora comprises actinomycetes with high biotechnological potential, due to their ability to produce secondary metabolites and enzymes. In this study, we report the draft genome sequence of Micromonospora sp. NBS 11-29, which showed antibacterial, cellulolytic, and xylanolytic activities under in vitro conditions.

Evaluation of three methods for preservation of Azotobacter chroococcum and Azotobacter vinelandii

La preservación de bacterias es asunto de granimportancia debido a que muchas de ellas son usadas enprocesos biotecnológicos que requieren mantener su viabilidad ypropiedades genéticas. En este estudio, se evaluaron tres métodospara la preservación de A. chroococcum C26 y A. vinelandii C27;criopreservación, liofilización, e inmovilización en polímerossecos, durante 60, 30 y 60 días, respectivamente. A su vez, seestudió el efecto de tres agentes protectivos para la liofilizacióny para la criopreservación y cuatro polímeros. La eficiencia delos métodos fue evaluada contando células viables y midiendoactividad como fijación de nitrógeno. Los resultados mostraronque la mejor técnica, la cual mantuvo la viabilidad y la actividad,fue la liofilización, seguida por inmovilización y criopreservación.La liofilización mantuvo estable la habilidad bacteriana para fijarnitrógeno, la tasa de sobrevivencia bacteriana (TSB) fue superioral 80%; y el mejor resultado se evidenció cuando se usó S/BSAcomo agente protectivo. La inmovilización mantuvo la BSRsuperior al 80%, y la fijación de nitrógeno fue disminuida en 20%.La criopreservación tuvo pérdida sustancial de viabilidad para C26(TSB aprox. 70%); mientras que C27 se preservó bien. La fijaciónde nitrógeno fue significativamente disminuida para ambas cepasindependientemente del agente crioprotectivo usado (P < 0.05).Los resultados sugieren que el éxito de los métodos de preservaciónpara Azotobacter depende de la técnica, el agente protectivo y la cepausada; siendo la liofilización con S/BSA la técnica con mejoresresultados para preservar las bacterias de este género...

Because the use of bacteria for biotechnological processes requires maintaining their viability and geneticstability, preserving them becomes essential. Here, we evaluated three preservation methods for A.chroococcum C26 and A. vinelandii C27; preservation methods: cryopreservation and immobilization in drypolymers for 60 days, and freeze-drying for 30. We evaluated their efficiency by counting viable cells andmeasuring nitrogen fixation activity. Additionally, we assessed the effect of three protective agents forfreeze-drying, three for cryopreservation, and four polymers. Freeze-drying proved the best technique tomaintain viability and activity, followed by immobilization and cryopreservation. Bacterial nitrogen fixingability remained unchanged using the freeze-drying method, and bacterial survival exceeded 80%; S/BSAwas the best protective agent. Immobilization maintained bacterial survival over 80%, but nitrogen fixationwas decreased by 20%. Lastly, cryopreservation resulted in a dramatic loss of viability for C26 (BSRapprox. 70%), whereas C27 was well preserved. Nitrogen fixation for both strains decreased regardless ofthe cryoprotective agent used (P < 0.05). In conclusion, the success of Azotobacter preservation methodsdepend on the technique, the protective agent, and the strain used. Our results also indicated that freezedryingusing S/BSA is the best technique to preserve bacteria of this genus...

Porque o uso de bactérias para processos biotecnológicos,requer a manutenção da sua viabilidade e estabilidade genética,preserva-las é essencial Avaliaram-se três métodos de preservação deA. chroococcum C26 e A. vinelandii C27; criopreservação, liofilização, eimobilização de polímeros secos. Examinamos também o efeito deagentes protetores para liofilizar, para a criopreservação, e polímeros.A eficiência foi avaliada contando as células viáveis e medindoa atividade como a fixação do azoto. Os resultados mostraramque a melhor técnica foi a liofilização seguida de imobilização ecriopreservação. A liofilização manteve inalterada a capacidadeda bactéria para fixar o azoto, e o melhor resultado foi observadoquando se usou S/BSA como agente protetor. A criopreservaçãoresultou em uma perda dramática de viabilidade para C26 (TSBaprox. 70%.), enquanto que C27 foi bem preservada. A fixaçãode azoto foi significativamente diminuída para ambas as estirpes,independentemente do agente crioprotector utilizado (P < 0.05).Em conclusão, os resultados sugerem que o êxito dos métodosde conservação de Azotobacter dependem da técnica, do agente deproteção, e da estirpe utilizada, sendo a liofilizacao com S/BSA amelhor técnica para preservar as bactérias deste género...