Genetic diversity of the complex Paspalum notatum Flügge (Paniceae: Panicoideae)

The genus Paspalum L. comprises approximately 400 species worldwide and about 220 in Brazil. Paspalum is ecologically and economically important, and has been very useful as pasture and P. notatum Flügge (bahiagrass) is a valuable forage grass in the subtropics. This species consists of several sexual (diploid) and apomictic (tetraploid, ocasionally tri and pentaploids) biotypes. In this work, inter simple sequence repeats (ISSR) markers were used to assess the genetic variability of a bahiagrass (P. notatum) collection. Vegetative tissues of 95 bahiagrass accessions were obtained from various locations in South America (Brazil, Argentina and Uruguay). A total of 91 reproducible ISSR fragments were observed and 89 fragments (97.5% of the total observed) were polymorphic. Cluster analyses (UPGMA) were performed from the ISSR data set and the results illustrate the genetic relationships among the 95 accessions of P. notatum. A comparison among molecular, morphological and ploidy levels data were done. ISSR markers were effective in distinguishing the genotypes analyzed, and a wide variability was observed for this species. These results add new information regarding the genetic diversity in P. notatum, thus contributing toward the biological knowledge of this species, and providing with subsides for future plant breeding and conservation programs.     

Collection,ex situ conservation and characterization of mangaba (Hancornia speciose Gomes) germplasm in coastal lowland of Northeastern Brazil

Genetic Resources and Crop Evolution - This study aimed to evaluate the Mangaba Genebank of Embrapa Tabuleiros Costeiros, Brazil, since its implementation in 2006 and characterize the accessions in...     

Purification and characterization of an alpha-mannosidase from the tropical fruit babaco ( Vasconcellea x heilbornii Cv. babaco)

An alpha-mannosidase (EC 3.2.1.24) present in the lyophilized latex of babaco ( Vasconcellea heilbornii ) has been purified to apparent homogeneity by native PAGE. The purification involves a three-step procedure with successive anion exchange with Q Sepharose HP, lectin affinity chromatography using ConA Sepharose 4B, and gel filtration using Superdex 200 prep grade. The molecular mass was determined to be in the range of 260-280 kDa by Superdex 200 prep grade gel filtration, and isoelectric focusing showed a pI range between 5.85 and 6.55, suggesting different glycosylated isoforms. The optimal temperature for the alpha-mannosidase was determined to lie between 50 and 60 degrees C, and the optimal pH was 4.5 at 50 degrees C. The K(m) value for p-nitrophenyl alpha-mannopyranoside (pNPM) was found to be 1.25 mM and the V(max), 2.4 microkat mg(-1) at 50 degrees C and 1.94 microkat mg(-1) at 40 degrees C. The pure alpha-mannosidase was specific for mannose and did not display activity for any other tested synthetic substrates.     

NH3 Volatilization from Urea-NBPT in Eucalyptus

High losses of nitrogen (N) by volatilization of ammonia from urea applied in Eucalyptus are expected due to the influence of plant residues on the soil surface. The study evaluated the N losses by volatilization of ammonia from urea coated with Thiophosphate N-(n-butil) triamide (NBPT) applied in soil with eucalyptus residues in surface under moisture treatments: fertilization in dry soil without irrigation; fertilization in dry soil with posterior irrigation depth (3 mm); fertilization in moist soil without irrigation and fertilization in moist soil with irrigation depth (3 mm). NBPT is a potential inhibitor of urease. Urea with NBPT shows lower losses by volatilization of ammonia when it is applied in dry soil; however in soil conditions of high moisture the losses as well as inhibitor effect of the NBPT are lower. The inhibitor effect of NBPT is reduced over time when it is subjected to moisture conditions.     

Fumigant toxicity of essential oils against Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae): a systematic review and meta-analysis

Our aim was to perform a qualitative review and a meta-analysis with 57 scientific articles (108 assays) published from 1 January 2000 to 31 June 2021 dealing with fumigant toxicity of essential oils (EOs) against Sitophilus zeamais. The studies were obtained from four electronic databases: Web of Science, SCOPUS, PubMed, and Google Scholar. The survey comprised 107 plant species belonging to 26 different families. Lethal concentration values (LC₅₀) of EOs were included in a random-effect model, and two subgroups were defined: “until 24 h” and “more than 24 h”. The EOs more frequently evaluated were those belonging to Lamiaceae (20.18%), Asteraceae (17.43%), Apiaceae (9.17%), and Rutaceae (6.42%). The global mean value was 21.37 (CI₉₅ 16.84–27.12), while the summary mean values of the subgroups were 41.45 (CI₉₅ 31.10–55.26) for “until 24 h” and 8.45 (CI₉₅ 5.72–12.48) for “more than 24 h”. Most species belonging to Apiaceae, Lamiaceae, Asteraceae, and Schisandraceae reported the highest insecticidal effects with mean values that ranged from 1.31 to 27.39 for “until 24 h” and from 0.57 to 5.31 for “more than 24 h”. Additionally, the toxicity of the most effective EOs was discussed by addressing their chemical composition and their major pure compounds chemical features.

     

A cultured greigite-producing magnetotactic bacterium in a novel group of sulfate-reducing bacteria

Magnetotactic bacteria contain magnetosomes--intracellular, membrane-bounded, magnetic nanocrystals of magnetite (Fe(3)O(4)) or greigite (Fe(3)S(4))--that cause the bacteria to swim along geomagnetic field lines. We isolated a greigite-producing magnetotactic bacterium from a brackish spring in Death Valley National Park, California, USA, strain BW-1, that is able to biomineralize greigite and magnetite depending on culture conditions. A phylogenetic comparison of BW-1 and similar uncultured greigite- and/or magnetite-producing magnetotactic bacteria from freshwater to hypersaline habitats shows that these organisms represent a previously unknown group of sulfate-reducing bacteria in the Deltaproteobacteria. Genomic analysis of BW-1 reveals the presence of two different magnetosome gene clusters, suggesting that one may be responsible for greigite biomineralization and the other for magnetite.     

Simmondsins quantification by spectrophotometry UV–vis in press cake and in jojoba seeds (Simmondsia chinensis (Link) Schneider), from Argentina

In this paper, we describe a simple, fast, and efficient method for the quantification of simmondsins and simmondsin's ferulates in jojoba seeds and residual cakes, without using expensive equipment or laborious techniques. Spectrophotometric measurements (UV–vis) were used for the quantification of the content of simmondsins, total ferulates and total simmondsins in jojoba seeds and residual cakes from the provinces of Catamarca and La Rioja, Argentina. The average values of such components found in seeds, in 100 g of dry and defatted sample, were 11.54 ± 0.91 and 2.24 ± 0.28 g of simmondsins and of simmondsin's ferulates, respectively, whereas the respective values in residual cakes were 10.08 ± 0.31 and 2.93 ± 0.64 g, respectively. A great diversity between the simmondsin contents and their ferulates in seed samples of different origins as well as in different clones was observed. The residual cakes did not present differences respect to the simmondsin contents; however, there were some difference with the simmondsin ferulates. These variations are due to the genetic antecedents of plants and the environmental conditions in which they grow.     

Spray-Dried Yerba Mate Extract Capsules: Clinical Evaluation and Antioxidant Potential in Healthy Individuals

Plant Foods for Human Nutrition - The aim of the present study was to evaluate the clinical effects and antioxidant potential of spray-dried yerba mate extract (SDME) capsules in healthy...     

Larvicidal Potential of the Halogenated Sesquiterpene (+)-Obtusol,Isolated from the Alga Laurencia dendroidea J. Agardh (Ceramiales: Rhodomelaceae), against the Dengue Vector Mosquito Aedes aegypti (Linnaeus) (Diptera: Culicidae)

Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (−)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (−)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (−)-elatol, with a LC₅₀ value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H₂DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound.