Molecular identification of Lactobacillus spp. associated with puba, a Brazilian fermented cassava food

Puba or carimã is a Brazilian staple food obtained by spontaneous submerged fermentation of cassava roots. A total of 116 lactobacilli and three cocci isolates from 20 commercial puba samples were recovered on de Man, Rogosa and Sharpe agar (MRS); they were characterized for their antagonistic activity against foodborne pathogens and identified taxonomically by classical and molecular methods. In all samples, lactic acid bacteria were recovered as the dominant microbiota (7.86 ± 0.41 log10 CFU/g). 16S-23S rRNA ARDRA pattern assigned 116 isolates to the Lactobacillus genus, represented by the species Lactobacillus fermentum (59 isolates), Lactobacillus delbrueckii (18 isolates), Lactobacillus casei (9 isolates), Lactobacillus reuteri (6 isolates), Lactobacillus brevis (3 isolates), Lactobacillus gasseri (2 isolates), Lactobacillus nagelii (1 isolate), and Lactobacillus plantarum group (18 isolates). recA gene-multiplex PCR analysis revealed that L. plantarum group isolates belonged to Lactobacillus plantarum (15 isolates) and Lactobacillus paraplantarum (3 isolates). Genomic diversity was investigated by molecular typing with rep (repetitive sequence)-based PCR using the primer ERIC2 (enterobacterial repetitive intergenic consensus). The Lactobacillus isolates exhibited genetic heterogeneity and species-specific fingerprint patterns. All the isolates showed antagonistic activity against the foodborne pathogenic bacteria tested. This antibacterial effect was attributed to acid production, except in the cases of three isolates that apparently produced bacteriocin-like inhibitory substances. This study provides the first insight into the genetic diversity of Lactobacillus spp. of puba.(AU)

Seed priming with light quality and Cyperus rotundus L. extract modulate the germination and initial growth of Moringa oleifera Lam. seedlings / Condicionamento de sementes com qualidade de luz e extrato de Cyperus rotundus L. modula a germinação e o crescimento inicial de plântulas de Moringa oleifera

Improving plant germination is essential to guarantee better quality seedlings. Thus, this research aimed to evaluate whether the seed priming with light quality (LIQ) and the aqueous extract of Cyperus rotundus (AEC) tuber could modulate the germination and initial growth of Moringa oleifera L. seedlings. The experimental design was a completely randomized in the 4x4 factorial scheme, composed of four LIQ conditions (white, blue, red, and distant red light) and four AEC concentrations (0, 25, 50 and 100%). Seed priming with red light reduced the average emergence time, while blue, red, and extreme red lights associated with 50% of aqueous extract of C. rotundus increased shoot initial length and photosynthetic pigment accumulation. Seed priming with blue light resulted in seedlings with a shorter final shoot length. However, application of 100% of aqueous extract of C. rotundus reversed this. The white light in combination with concentrations of 50 and 100% of AEC promoted a higher relative shoot growth rate of seedlings. The research revealed that seed priming with light quality and aqueous extracts of C. rotundus tubers modulates the germination and initial growth of M. oleifera seedlings. More work needs to be done to determine the responsible compounds in AEC that is responsible for priming growth as phytohormones.

A melhoria da germinação de plantas é fundamental para garantia de mudas de melhor qualidade. Assim, objetivou-se avaliar se o condicionamento de sementes com qualidade de luz (light quality - LIQ) e extrato aquoso de tubérculos de Cyperus rotundus (AEC) modula a germinação e o crescimento inicial de plântulas de Moringa oleifera. Utilizou-se delineamento inteiramente casualizado, em esquema fatorial 4x4, sendo quatro condições de LIQ (luz branca, azul, vermelha e vermelho distante) e quatro concentrações de AEC (0, 25, 50 e 100%). O condicionamento de sementes com luz vermelha reduziu o tempo médio de emergência, enquanto que as luzes azul, vermelha e vermelho extremo associadas a 50% de extrato aquoso de C. rotundus aumentaram o comprimento inicial da parte aérea e o acúmulo de pigmentos fotossintéticos. Condicionamento de sementes com luz azul induziu a formação de plântulas com menor comprimento final da parte aérea, no entanto, a aplicação de 100% de extrato aquoso de C. rotundus reverteu o menor crescimento. A luz branca associada às concentrações de 50 e 100% de fitormônios promoveu maior taxa de crescimento relativo da parte aérea de plântulas. Nossa pesquisa mostra que o condicionamento de sementes com radiação espectral de luz e extrato aquoso de tubérculos de Cyperus rotundus modula a germinação e o crescimento inicial de plântulas de Moringa oleifera. Mais trabalhos precisam ser feitos para determinar os compostos do AEC responsáveis que que atuam como fitormônios e são responsáveis pelo crescimento inicial.