Haywood Dail Laughinghouse

Novel bacterial isolate from Permian groundwater, capable of aggregating potential biofuel-producing microalga Nannochloropsis oceanica IMET1.

ABSTRACT Increasing petroleum costs and climate change have resulted in microalgae receiving attention as potential biofuel producers. Little information is available on the diversity and functions of bacterial communities associated with biofuel-producing algae. A potential biofuel-producing microalgal strain, Nannochloropsis oceanica IMET1, was grown in Permian groundwater. Changes in the bacterial community structure at three temperatures were monitored by two culture-independent methods, and culturable bacteria were characterized. After 9 days of incubation, N. oceanica IMET1 began to aggregate and precipitate in cultures grown at 30°C, whereas cells remained uniformly distributed at 15°C and 25°C. The bacterial communities in cultures at 30°C changed markedly. Some bacteria isolated only at 30°C were tested for their potential for aggregating microalgae. A novel bacterium designated HW001 showed a remarkable ability to aggregate N. oceanica IMET1, causing microalgal cells to aggregate after 3 days of incubation, while the total lipid content of the microalgal cells was not affected. Direct interaction of HW001 and N. oceanica is necessary for aggregation. HW001 can also aggregate the microalgae N. oceanica CT-1, Tetraselmis suecica, and T. chuii as well as the cyanobacterium Synechococcus WH8007. 16S rRNA gene sequence comparisons indicated the great novelty of this strain, which exhibited only 89% sequence similarity with any previously cultured bacteria. Specific primers targeted to HW001 revealed that the strain originated from the Permian groundwater. This study of the bacterial communities associated with potential biofuel-producing microalgae addresses a little-investigated area of microalgal biofuel research and provides a novel approach to harvest biofuel-producing microalgae by using the novel bacterium strain HW001.

Bioindicator of Genotoxicity: The Allium cepa Test

Solange Bosio Tedesco1,2 and Haywood Dail Laughinghouse IV3,4 1Graduate Program in Agrobiology, Department of Biology Universidade Federal de Santa Maria (UFSM), Santa Maria 2Graduate Program in Agronomy, UFSM, Santa Maria 3National Museum of Natural History, Smithsonian Institution, Washington, DC 4College of Computer, Mathematical & Natural Sciences University of Maryland, College Park, MD 1,2RS Brazil 3,4USA

Evaluation of the allelopathic, genotoxic, and antiproliferative effect of the medicinal species Psychotria brachypoda and Psychotria birotula (Rubiaceae) on the germination and cell division of Eruca sativa (Brassicaceae)

Biological assays are widely used to monitor toxic and allelopathic substances. The present study aimed to evaluate the allelopathic, genotoxic, and antiproliferative potential of aqueous extracts of Psychotria brachypoda (Müll. Arg.) Britton and Psychotria birotula Smith & Downs in two concentrations on the germination and cell division of Eruca sativa Hill. seeds. The biological assay was conducted in a controlled growth chamber. For monitoring the allelopathic effect, the following variables were evaluated: total number of germinated seeds, seedling root length, germination velocity index, and germination percentage. The means were compared using the Tukey test and orthogonal contrasts were undertaken to better compare the variables. To evaluate the antiproliferative and genotoxic effects, seedling roots were collected and the squashing technique was followed for preparation of slides. The results of the present study demonstrated that the medicinal species Psychotria brachypoda and Psychotria birotula inhibited root growth, germination velocity index, and germination percentage in seeds of arugula, in addition to inhibiting cell division and inducing chromosomal alterations in Eruca sativa. We conclude that the studied species have alellopathic, genotoxic, and antiproliferative effects on Eruca sativa in both concentrations studied.

Mutagenic and antimutagenic effects of Eugenia uniflora L. by the Allium cepa L. test

Eugenia uniflora (Surinam cherry tree) is an important species in traditional medicine and is used to decrease blood pressure and prevent heartburn, bronchitis, colic and stomachaches. The tealeaves have antirheumatic, anti-dysenteric, and febrifuge properties and are used to treat diabetes. This study aimed to assess the antiproliferative, mutagenic and antimutagenic effects of the leaves and fruits of E. uniflora through the Allium cepa test. The infusions were prepared using dried leaves (6.l−1 and 24 gl−1) and the oil extraction was undertaken using hydrolyzation (0.25%, in ethanol). For juice preparation, fruit pulp with and without seeds was used. Allium cepa root tips were used for slide preparation following the squashing technique. Analysis of 500 cells for each bulb was undertaken, 250 of each root, summing 2500 cells per treatment, a total of 17,500 and 10,000 cells in the first and second experiments, respectively. The mitotic index was calculated and statistical analyses were performed. We found that the aqueous extract and oil of E. uniflora has mutagenic activity at low concentrations and the extract at a higher than average concentration can be considered antimutagenic. Furthermore, both juice extracts with and without seeds have anti-proliferative capacity.

Genotoxic and antiproliferative potential of extracts of Echinodorus grandiflorus and Sagittaria montevidensis (Alismataceae)

Abstract The economic potential of the germplasm of medicinal species is a rich resource that should be preserved and used. The medicinal species Echinodorus grandiflorus and Sagittaria montevidensis belong to the family Alismataceae. Depurative, diuretic, anti-inflammatory, antivenin, and anti-rheumatic actions have been associated with E. grandiflorus, where the leaves are the main part used. Sagittaria montevidensis does not yet have its medicinal properties known and has a wide morphological variability, and is sometimes confused with E. grandiflorus. The present study aimed to evaluate the genotoxic and antiproliferative potential of extracts of dry leaves of E. grandiflorus and S. montevidensis on the cell cycle of Allium cepa, as well as undertake analysis by high performance liquid chromatography (HPLC-DAD) for the quantification of the compounds from the extracts. A. cepa bulb rootlets were submitted to the extracts for 24 h, prepared from plant material at two concentrations, 6 g dm−3 and 24 g dm−3 for each species, and two controls. Afterwards, the analysis of cell division and calculation of the mitotic index was undertaken. Part of the extracts was analyzed by HPLC-DAD. The results differed significantly between the controls and the treatments of both groups; the species did not have antimutagenic activity. The phytochemical analysis presented higher levels of caffeic acid and flavonoid glycoside in E. grandiflorus and phenolic glycoside in S. montevidensis. This study showed that the extracts of E. grandiflorus and S. montevidensis contain genotoxic potential and when used in high concentrations, anti-proliferative potential. HPLC-DAD revealed flavonoids and phenolic acids for both species.

Determination of phenolic compounds and assessment of the genotoxic and proliferative potential of Psidium cattleianum Sabine (Myrtaceae) fruits

Abstract The purpose of this paper was to investigate the proliferative and genotoxic activity of juices from fruits of Psidium cattleianum, also known as strawberry guava, using the Allium cepa test. Fruits were collected and frozen for subsequent juice preparation at a concentration of 125 g l−1. The treatments consisted of T1: distilled water (negative control), T2: juice of yellow strawberry guava collected in Arroio Grande, T3: juice of yellow strawberry guava collected in Palma, T4: juice of red strawberry guava collected at UFSM, and T5: 1% glyphosate solution (positive control). Eight thousand cells per treatment were analysed and the mitotic indices (MI) were calculated. The juice samples were analysed by high-performance liquid chromatography (HPLC). Statistical analyses were performed using the chi-square and Tukey tests (p < 0.05). The results show irregularities in the cell division, mainly during metaphase, and an antimitotic effect in addition to an increase in the MI in treatments containing strawberry guava juice. Using HPLC, epicatechin was predominant in T2 and T4, and isoquercitrin in T3. Overall, strawberry guava has proliferative and genotoxic effects on the cell division of A. cepa, as well as an antimitotic action preventing the mitotic spindle from forming.

Meiotic analysis of the germoplasm of three medicinal species from Asteraceae family

Cytogenetic characterization was carried out on 12 accessions from Aster squamatus (Spreng.) Hieron., Pterocaulon polystachyum DC, and Solidago microglossa DC by studying their meiotic behavior and pollen viability. These species are from the Asteraceae family, native to Rio Grande do Sul State, Brazil, and are important for medicinal use. Young inflorescences with four accessions of each species were collected, fixed in ethanol-acetic acid (3:1), and conserved in ethanol 70% until use. The method used was that of squashing the anthers and coloring with acetic orcein 2%. Meiosis was regular in all accessions, presenting chromosomal associations preferentially bivalent, where n=10 was found for Aster squamatus and n=9 for Pterocaulon polystachyum, and Solidago microglossa. The studied accessions presented a Meiotic Index (MI) that varied from 65% to 87% in Aster squamatus, 85% to 92% in Pterocaulon polystachyum, and 64% to 92% in Solidago microglossa, indicating meiotic stability, although irregularities appeared during the cellular division. The pollen viability estimative was high in all studied accessions. These results indicate that the studied species can be included in future studies of genetic breeding.