Biocontrol of soil diseases and soil profile associated with rhizosphere of rice (Oryza sativa Subsp. Japonica) growing paddy fields in Kansai region,Japan

ABSTRACT

This research focused on in vitro and in vivo biocontrol of two major rice diseases, Bacterial Leaf Blight caused by Xanthomonus oryzae pv oryzae (Xoo) and Sheath Blight caused by Rhizoctonia solani. Furthermore, the soil of paddy fields in Kansai region, Japan was analysed for the presence of these pathogens, and their microbial communities were evaluated according to the location and management systems. For biocontrol, the rhizospheric bacteria were isolated and molecularly identified. The results indicated that DAR17225040 and DAR17225017 were 99% similar to Bacillus aryabhattai and Bacillus megaterium. The isolated bacteria were able to suppress Bacterial Leaf Blight and Sheath Blight disease 78% and 86% respectively, under greenhouse conditions. The 16S amplicon sequencing (Illumina MiSeq 250bp) was used to analyse the bacterial community in paddy fields of soil taken from five locations under conventional and organic systems. Xoo and R. solani were detected in sampled soil, however, no clear difference was noted, regarding systems. From amplicon sequencing data, Chloroflexi, Acidobacteria, Proteobacteria, Actinobacteria, Planctomycetes were the dominant phyla of rice soil in Kansai region. The phylum Kazan-3B-28 was found more in organic system than conventional. The bacterial community was more affected by location and soil type than by management systems.     

Characterization of phenolic components in polar extracts of Eucalyptus globulus Labill. bark by high-performance liquid chromatography-mass spectrometry

High-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) and tandem mass spectrometry (MS(n)) were used to investigate the phenolic constituents in methanol, water, and methanol/water extracts of Eucalyptus globulus Labill. bark. Twenty-nine phenolic compounds were identified, 16 of them referenced for the first time as constituents of E. globulus bark, namely, quinic, dihydroxyphenylacetic, and caffeic acids, bis(hexahydroxydiphenoyl (HHDP))-glucose, galloyl-bis(HHDP)-glucose, galloyl-HHDP-glucose, isorhamentin-hexoside, quercetin-hexoside, methylellagic acid (EA)-pentose conjugate, myricetin-rhamnoside, isorhamnetin-rhamnoside, mearnsetin, phloridzin, mearnsetin-hexoside, luteolin, and a proanthocyanidin B-type dimer. Digalloylglucose was identified as the major compound in the methanol and methanol/water extracts, followed by isorhamnetin-rhamnoside in the methanol extract and by catechin in the methanol/water extract, whereas in the water extract catechin and galloyl- HHDP-glucose were identified as the predominant components. The methanol/water extract was shown be the most efficient to isolate phenolic compounds identified in E. globulus bark.     

A national serological survey to verify Australia's freedom from porcine reproductive and respiratory syndrome

Objective To provide serological data to support Australia's claim of freedom from porcine reproductive and respiratory syndrome.
Design A national serological survey was designed to provide 99% confidence of detecting at least one infected pig herd in Australia, assuming that at least 5% of herds would have been exposed to porcine reproductive and respiratory syndrome virus and that at least 25% of the 'finisher' pigs in these herds would have antibodies to the virus.
Procedure A two-stage testing regime was used. All samples were tested with a commercially available enzyme-linked immunosorbent assay. If assay reactions were found, all samples from the herd were to be tested using the indirect immunofluorescence antibody assay.
Results Of the 875 samples from 163 herds from all States in Australia, there was some evidence of reactivity in only four samples from four herds on the enzyme-linked immunosorbent assay. Further testing using the indirect immunofluorescence antibody assay according to the study protocol demonstrated that the reactions were not due to the presence of specific porcine reproductive and respiratory syndrome virus antibodies in the sera.
Conclusion The results of this study support the view that Australian pigs are free of porcine reproductive and respiratory syndrome virus.     

Ultrastructural characteristics of blood cells of juvenile loggerhead sea turtles (Caretta caretta)

Ultrastructural characteristics of erythrocytes, heterophils, eosinophils, lymphocytes, monocytes and thrombocytes of the loggerhead sea turtle (Caretta caretta) were evaluated, using blood samples from 15 healthy juvenile animals. Except for the eosinophils, the rest of the white blood cells from loggerhead turtles had similar ultrastructural characteristics compared with blood cells from other sea turtle species. Eosinophils from loggerhead turtles were homogeneous in size, and no crystalline structures were observed within the granules. This paper provides an ultrastructural characterization of blood cells of loggerhead sea turtles, as a reference for future haematological studies of this species.     

How much importance is given to native plants in cities’ treescape? A case study in Fortaleza,Brazil

Even though Brazil is a mega-diverse country, many Brazilian cities prioritize exotic plants in their treescapes. Aiming to evaluate how much the treescape in Fortaleza (the fifth largest city in Brazil) is aligned with the policy of valorization of native biodiversity, we sampled street and backyard trees surrounding one of the few vegetation fragments of the city, which is an area considered a priority for conservation. We used the vegetation fragment's flora as reference to compare the potential number of local native species with the actual number of native species in the treescape of the site. To account how much of the native flora was present in the surrounding treescape, we made an inventory of the trees in streets, squares and backyards around the vegetation and compared with the native flora of the vegetation fragment. We then compared the ratio of native to exotic species and checked how many native species of the fragment were also in the surrounding treescape. Exotics were prevalent in both number of species and number of individuals, comprising 70% of the species and 86% of the individuals of public spaces, and 79% of the species and 78% of the individuals of private spaces. Only 14% of the native species of the vegetation were also represented in the treescape, and, in general, they comprehended only a few individuals. We argue that the city's treescape should be re-evaluated in order to value native plants more. Native plants in the treescape could be used as an environmental education tool to publicize native biodiversity to citizens.     

MALDI-TOF, HPLC-ESI-TOF and 13C-NMR characterization of chestnut (Castanea sativa) shell tannins for wood adhesives

MALDI-TOF, HPLC-ESI-TOF and 13C-NMR techniques were used to analyse the structure of non-purified aqueous chestnut shell tannin extracts. In addition, the influence of the extraction agent (water or aqueous solutions of Na₂SO₃ and/or NaOH) on tannin structure was analysed by MALDI-TOF in order to select the extract with the best properties for wood adhesives. Using HPLC-ESI-TOF, catechin/epicatechin, gallocatechin/epigallocatechin, dicatechin structures, dicatechin structures without a hydroxyl group, galloyl-glucoses and ellagic acid were identified as the main monomeric components in the aqueous extract. 13C-NMR and MALDI-TOF spectra revealed that extracts are mostly composed of procyanidin and prodelphinidin structures although prorobinetidins might be also present. MALDI-TOF spectrometry was used to identify the extract oligomeric components. Extractions with Na₂SO₃ and/or NaOH produced changes in the predominant structures in the extracts and on the amount of sugar units linked to the flavonoid structures, which decreased in the presence of Na₂SO₃. Extract obtained using low Na₂SO₃ and NaOH concentrations (1.5 and 0.75 %, respectively) was selected as more suitable for wood adhesive preparation.     

Ultrastructural and Enzymatic Activity of Membranous Vesicles Isolated from Canine Seminal Plasma

The objectives of this study were to verify the presence of membranous vesicles (MV) in canine seminal plasma by mean of transmission electron microscopy (TEM), to describe the ultrastructural characteristics and to identify some enzymatic activity associated with them. Semen samples, collected by digital manipulation from dogs with proven fertility, were pooled and used for membrane vesicles preparation according to conventional procedures. TEM observations showed the existence of vesicular membranous structures of more or less spherical shape with different sizes. These vesicles were surrounded by a single‐, double‐ or multiple‐layered laminar membranes. The mean vesicle diameter was 117.6 ± 86.9 nm ranging from 24.4 to 716.6 nm. Enzyme activity determinations showed the presence of adenosine deaminase, 5′‐nucleotidase, ADPase, ATPase, dipeptilpeptidase IV, alkaline phosphatase, total acid phosphatase and prostatic acid phosphatase, while the aminopeptidase activity was absent. In conclusion, results of this study, compatible with results from other mammals, showed for the first time the presence of MV, their ultrastructural and enzymatic characteristics in dog seminal plasma.     

Mineralogical changes caused by grape production in a regosol from subtropical Brazilian climate

Purpose

Inadequate soil use and management practices promote commonly negative impacts on the soil constituents and their properties, with consequences to ecosystems. As the soil mineralogy can be permanently altered due to soil use, this approach can be used as a tool to monitor the anthropogenic pressure. The objective of the present study was to assess the mineralogical alterations of a Brazilian regosol used for grape production for 40?years in comparison with a soil under natural vegetation (forest), aiming to discuss anthropogenic pressure on soils.

Material and methods

Soil samples were collected at depths of 0?C0.20 and 0.20?C0.40?m from vineyard production and natural vegetation sites. Physical and chemical parameters were analysed by classic approaches. Mineralogical analyses were carried out on <2?mm, silt and clay fractions. Clay minerals were estimated by the relative percentage of peak surface area of the X-ray patterns.

Results and discussion

Grape production reduced the organic matter content by 28?% and the clay content by 23?% resulting in a decreasing cation exchange capacity. A similar clay fraction was observed in both soils, containing kaolinite, illite/mica and vermiculite with hydroxy-Al polymers interlayered. Neither gibbsite nor chlorite was found. However, in the soil under native vegetation, the proportion of illite (79?%) was higher than vermiculite (21?%). Whereas, in the soil used for grape production during 40?years, the formation of vermiculite was promoted.

Conclusions

Grape production alters the proportions of soil constituents of the regosol, reducing clay fraction and organic matter contents, as well as promoting changes in the soil clay minerals with the formation of vermiculite to the detriment of illite, which suggests weathering acceleration and susceptibility to anthropogenic pressure.

Recommendations and perspectives

Ecosystems in tropical and subtropical climates can be more easily and permanently altered due to anthropogenic pressure, mainly as a consequence of a great magnitude of phenomena such as temperature amplitude and rainfall that occurs in these regions. This is more worrying when soils are located on steep grades with a high anthropogenic pressure, like regosols in Southern Brazil. Thus, this study suggests that changes in soil mineralogy can be used as an important tool to assess anthropogenic pressure in ecosystems and that soil quality maintenance should be a priority in sensible landscapes to maintain the ecosystem quality.