Genome of Herbaspirillum seropedicae Strain SmR1, a Specialized Diazotrophic Endophyte of Tropical Grasses

The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme—GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species

Effects of the probiotic Bifidobacterium animalis subsp. lactis on the non-surgical treatment of periodontitis. A histomorphometric, microtomographic and immunohistochemical study in rats.

Lactobacillus probiotics have been investigated in periodontitis. However, the effects of the genus Bifidobacterium on periodontitis are hardly known. This study evaluated the effects of the probiotic (PROB) Bifidobacterium animalis subsp. lactis (B. lactis) HN019 as an adjunct to scaling and root planing (SRP) in rats with experimental periodontitis (EP). At baseline, 32 rats were assigned to 4 groups: C (control), PROB, EP-SRP and EP-SRP-PROB. In groups EP-SRP and EP-SRP-PROB, the mandibular first molars of the animals received a ligature. At day 14, the ligatures were removed and SRP was performed. Animals of groups PROB and EP-SRP-PROB were orally administered with 10 mL/day of 109 colony forming units of B. lactis HN019 for 15 days, starting at day 14. Animals were euthanized at day 29. Histomorphometric, microtomographic and immunohistochemical analyses were performed. Microbiological effects of B. lactis on biofilm were also evaluated. Data were statistically analyzed (ANOVA, Tukey; Kruskal-Wallis, Dunn's; Two-tailed t-test; p<0.05). Group EP-SRP-PROB presented reduced alveolar bone resorption and attachment loss when compared with Group EP-SRP (p<0.05). Group EP-SRP-PROB showed significantly fewer osteoclasts, increased expression of anti-inflammatory cytokines and reduced expression of proinflammatory cytokines compared with Group EP-SRP (p<0.05). B. lactis promoted a higher ratio between aerobic and anaerobic bacteria in biofilm samples (p<0.05). B. lactis HN019 may have a role in the treatment of EP in rats, as an adjunct to SRP

Immunohistochemical analyses—IL-1β and CINC.

<p>Medians, interquartile range and maximum and minimum values of the immunolabeling scores for IL-1β (A) and CINC (B), with comparisons among groups. Photomicrographs showing immunolabeling for IL-1β (C-F) and CINC (G-J) in the furcation regions of mandibular first molars: Group C (C and G); Group PROB (D and H); Group EP-SRP (E and I); Group EP-SRP-PROB (F and J). Abbreviations: ab = alveolar bone; ct = connective tissue; pdl = periodontal ligament; * = <i>p</i><0.05. Scale bars: C-J = 80 μm. (Hematoxylin counterstaining).</p

Histomorphometric analysis of periodontal tissues.

<p>Means and standard deviations of ANB (A; furcation area) and AL (B; interproximal area), with comparisons among groups. Photomicrographs of periodontal tissues in the furcation (C-F) and interproximal areas (G-J) of mandibular first molars: Group C (C and G); Group PROB (D and H); Group EP-SRP (E and I); Group EP-SRP-PROB (F and J). Abbreviations and symbols: ab = alveolar bone; ct = connective tissue; pdl = periodontal ligament; ANB = area of no bone; AL = attachment loss; FM = first molar; SM = second molar; black arrows = cementoenamel junction; white arrows = epithelial attachment; * = <i>p</i><0.05; ** = <i>p</i><0.01; *** = <i>p</i><0.001. Scale bars: C-J = 200 μm. (Hematoxylin and Eosin stain).</p

Immunohistochemical analyses—IL-10 and TGF-β1.

<p>Medians, interquartile range and maximum and minimum values of the immunolabeling scores for IL-10 (A) and TGF-β1 (B), with comparisons among groups. Photomicrographs showing immunolabeling for IL-10 (C-F) and TGF-β1 (G-J) in the furcation regions of mandibular first molars: Group C (C and G); Group PROB (D and H); Group EP-SRP (E and I); Group EP-SRP-PROB (F and J). Abbreviations: ab = alveolar bone; ct = connective tissue; pdl = periodontal ligament; * = <i>p</i><0.05. Scale bars: C-J = 80 μm. (Hematoxylin counterstaining).</p