Genetic diversity via REML-BLUP of ex situ conserved macauba [Acrocomia aculeata (Jacq.) Lodd. ex Mart.] ecotypes

Genetic Resources and Crop Evolution - Macauba [Acrocomia aculeata (Jacq.) Lodd. ex Mart.], a palm tree native to Brazil, has a high potential as an alternative source for vegetal oil production....     

Characterization of the invasion of porcine endothelial cells by Streptococcus suis serotype 2

Streptococcus suis serotype 2 is an important swine pathogen associated mainly with meningitis. In a previous study, we demonstrated the ability of S. suis serotype 2 to adhere to and invade immortalized porcine brain microvascular endothelial cells (PBMECs) forming the blood-brain barrier. The aim of the current work was to further characterize the mechanism(s) by which S. suis invades porcine endothelial cells. The ability of several S. suis strains to interact with PBMECs was not found to correlate with their geographic origin, virulence, host of origin, or suilysin production. Characterization studies demonstrated that proteinaceous adhesins/invasins, cell wall components, lipoteichoic acid, and serum components (including fibronectin) were involved in interactions between S. suis and PBMECs. In addition to PBMECs, S. suis was able to adhere to and invade 2 porcine aortic endothelial cell lines and primary PBMECs.     

The horizontal barrier effect of stems on the foraging behaviour of cattle grazing five tropical grasses

The rate of nutrient intake (RNI) is a primary determinant of animal performance in grazing cattle and depends on both diet quality and instantaneous intake rate (IIR). In turn, diet quality and IIR are a function of the foraging behaviour of the animal (selectivity, bite mass and bite rate) and the characteristics of the sward. In this study we evaluated the effect of the stem density and the tensile resistance of stems on the foraging behaviour of cattle grazing tropical pasture species. The methodology involved the use of small sown microswards offered to tethered cattle. The experiment consisted of a factorial combination of five tropical grasses [Bothriochloa pertusa (Bp), Chloris barbata (Cb), Chloris gayana (Cg), Cynodon dactylon (Cd) and Heteropogon contortus (Hc)] and three stem densities (0, 400 and 800 stems m^− 2). Bp and Cd had stems of significantly lower tensile resistance (19 and 15 N respectively) (Group 1) than those of Cb, Cg and Hc (110, 211 and 167 N respectively) (Group 2). The steers avoided stems of Group 2 and thus, reduced bite area, bite mass, IIR and RNI as stem density increased. However, the animals did not avoid stems of Group 1 and there was no effect of stem density on any of the foraging behaviour variables when cattle grazed species in Group 1. These results confirm that RNI and plant part selection is closely associated with the tensile resistance of the stem.     

Potential of a Fusarium eumartii culture filtrate on the screening for wilting resistance in potato

Summary Fusarium solani f.sp. eumartii Carp. Snyder and Hansen (Fusarium eumartii) is a soil inhabitant that induces the so-called Potato Wilt and Stem End Rot disease. Prior to wilting, the pathogen induces peculiar small bronze spots on the leaflets. Failure to isolate F. eumartii from infected leaflets suggests the involvement of a toxin in the disease. The fungus was grown in liquid Richard's medium and thereafter a filtrate was obtained dialyzing (MW cutoff 12,000–14,000) and sterilizing the culture by filtration (0.22 m). Potato leaves treated with both the pathogen or the filtrate showed symptoms of bronze spots and significantly higher electrolyte leakage when compared to controls. Tomato leaves showed neither bronze spots nor electrolyte leakage after plant inoculation with the pathogen or with the filtrate treatment. Both, the absence of visible symptoms and the lack of electrolyte leakage in tomato could be associated to a certain degree of host specificity of the F. eumartii filtrate towards potato. The filtrate also induced symptoms similar to infections by F. eumartii in adult plants and in vitro plantlets of cultivars Huinkul MAG and Kennebec. Callus responses to the filtrate were related to responses of the cultivars to the pathogen in greenhouse. These results show the potential of the culture filtrate of F. eumartii for use in screening for wilting resistance.     

Seroepidemiology of neosporosis in dairy cattle in Uruguay

A seroepidemiological survey of Neospora caninum was done in a dairy farm in Uruguay employing indirect fluorescent antibody test (IFAT). Sera from 217 cattle (155 cows, 31 heifers and 31 calves) were tested for N. caninum antibodies in July 2000 and it was found that abortions were significantly associated with the seropositivity of the cows by chi(2)-test (P = 0.025). The cows with an IFAT titre of 1:3200 were at a significantly higher risk of abortion than seronegative cows (P = 0.0013). Neospora organisms were detected in the brains of two aborted foetuses by immunohistochemical examination. The infection of N. caninum was considered postnatal because of the even distribution of seropositive cows (60%), low seroprevalence (20%) in calves and no significant correlation in the serostatus between calves and their dams (P = 0.43). A fitted binomial generalised linear model revealed that there was an increasing risk of abortion with increasing IFAT titre and increasing age between 2 and 6 years.     

Relationship Between Soft Wheat Flour Physicochemical Composition and Cookie‐Making Performance

Nowadays in Argentina, cookies, crackers, and cakes are made of flour obtained from bread wheat with additives or enzymes that decrease the gluten strength but increase production costs. The present research work aims to study the relationship between flour physicochemical composition (particle size average [PSA], protein, damaged starch [DS], water soluble pentosans [WSP], total pentosans [TP], and gluten), alkaline water retention capacities behavior, solvent retention capacities profile (SRC) and cookie‐making performance in a set of 51 adapted soft wheat lines with diverse origin to identify better flour parameters for predicting cookie quality. Cookie factor (CF) values were 5.06–7.56. High and significant negative correlations between sucrose SRC (–0.68), water SRC (–0.65), carbonate SRC (–0.59), and CF were found, followed by lactic SRC that presented a low negative but significant correlation (r = –0.35). The flour components DS (r = –0.67), WSP (r = –0.49), and TP (r = –0.4) were negatively associated to CF. PSA showed a negative correlation with CF (r = –0.43). Protein and gluten were the flour components that affected cookie hardness, but no significant correlation were found with pentosan or DS content. A prediction equation for CF was developed. Sucrose SRC, PSA, and DS could be used to predict 68% of the variation in cookie diameter. The cluster analysis was conducted to assess differences in flour quality parameters among genotypes based on CF. Clusters 1 and 4 were typified by lower CF (5.70 and 5.23, respectively), higher DS, pentosan content, and SRC values. Cluster 2 with a relative good CF (6.47) and Cluster 3 with the best cookie quality, high CF (7.32) and low firmness, and the lowest DS, TP, WSP content, and sucrose SRC values.     

New invasion of <Emphasis Type="Italic">Bemisia tabaci</Emphasis> Mediterranean species in Brazil associated to ornamental plants

In Brazil, the first major invasion event of Bemisia tabaci was that of Middle East–Asia Minor 1 (MEAM1) species, formerly termed as B biotype, which commenced in the 1990s mainly by ornamental plants in São Paulo State. More than two decades after this invasion, the presence of the Mediterranean (MED) species of B. tabaci, formerly Q biotype, was reported in Rio Grande do Sul, the southernmost State of Brazil, and now in São Paulo and Paraná States, in southeastern Brazil. Specimens of whiteflies collected from commercial begonia, hydrangea, petunia and poinsettia greenhouses in São Paulo, and also from begonias and poinsettias collected in flower shops in Paraná, were all identified as belonging to MED species. Furthermore, the secondary endosymbionts Arsenophonus, Hamiltonella and Rickettsia of MED from São Paulo and Paraná were detected by PCR and their presence confirmed by sequencing and FISH analysis, and those results differed from MED detected in Rio Grande do Sul that harbored only Hamiltonella and Cardinium. Our results suggest a new MED invasion into Brazil and is associated with ornamental plants. The two MED populations are genetically different and suggest that they are separate invasions.     

Liming as an ameliorator of copper toxicity in black oat (Avena strigosa Schreb.)

This study aimed to assess the effect of liming as an ameliorator of copper (Cu) toxicity in black oats (Avena strigosa Schreb.) grown in soil with a sandy texture. The treatments were soil supplementation with increasing doses of lime (0.0, 0.5 and 1.0 g kg^?1) and two of Cu (0 and 50 mg kg^?1). Pre-germinated black oat seeds were sown for 30 days in the soil, subsequently, the plant height, root and shoot dry mass and concentration of total chlorophyll, chlorophylls a and b, carotenoids and total soluble carbohydrates and starch were analyzed. The dose of 50 mg kg^?1 soil Cu caused a toxic effect on black oat plant growth and development, affected the internal distribution of nutrients, decreased the leaf chlorophyll concentration and increased the leaf concentration of total soluble carbohydrates and starch. Increasing lime doses ameliorated the toxic effects of Cu.     

Synthesis and insecticidal activity of new pyrethroids

BACKGROUND: Pyrethroids are among the most potent pesticides known, with great potential for structural variation with retention or enhancement of potency. The simple methyl ester is easier to prepare (at least one step shorter) than the more complex pyrethroids modified on the alcohol moiety. The objective was to synthesise methyl esters of pyrethroid acids containing an aromatic ring on the acid moiety and evaluate their biological activity against Ascia monuste orseis Latr., Tuta absoluta Meyrick, Periplaneta americana (L.), Musca domestica L. and Sitophilus zeamais (Motsch.). RESULTS: The synthetic sequence required seven steps: protection of the hydroxyl groups of D ‐mannitol, diol oxidative cleavage with sodium metaperiodate, alkene formation by Wittig reaction with methoxycarbonylmethylidene(triphenyl)phosphorane, cyclopropanation, acetal hydrolysis with perchloric acid and oxidative cleavage with sodium metaperiodate gave methyl (1S, 3S)‐3‐formyl‐2,2‐dimethylcyclopropane‐1‐carboxylate. The final step comprised reaction of the aldehyde with five different aromatic phosphorus ylides to give the pyrethroids. CONCLUSION: An efficient and versatile synthesis of ten new pyrethroid methyl esters has been accomplished from the readily available D ‐mannitol in seven steps. All compounds showed insecticidal activity, and methyl (1S, 3S)‐3‐[(Z)‐2‐(4‐chlorophenyl)vinyl]‐2,2‐dimethylcyclopropane‐1‐carboxylate was the most active, killing 90% of A. monuste orseis and 100% of T. absoluta and P. americana. Copyright © 2009 Society of Chemical Industry     

Generation of a Mixolab Profile After the Evaluation of the Functionality of Different Commercial Wheat Flours for Hot‐Press Tortilla Production

Refined wheat flours commercially produced by five different U.S. and Mexican wheat blends intended for tortilla production were tested for quality and then processed into tortillas through the hot‐press forming procedure. Tortilla‐making qualities of the flour samples were evaluated during dough handling, hot pressing, baking, and the first five days on the shelf at room temperature. The predominant variables that affected the flour tortilla performance were wet gluten content, alveograph W (220–303) and P/L (0.70–0.94) parameters, farinograph water absorption (57%) and stability (10.8–18.7 min), starch damage (5.43–6.71%), and size distribution curves (uniform particle distribution). Flours produced from a blend of Dark Northern Spring (80%) and Mexican Rayon (20%) wheat had the highest water absorption, and tortillas obtained from this blend showed the highest diameter and lowest thickness. The whitest and best textured tortillas were obtained from the flour milled from three hard types of Mexican wheat blend. A Mixolab profile was generated from the best tortilla flours, those produced by mills 3 and 4. The Mixolab profile showed that a good flour for hot‐press tortillas had a relatively lower absorption and short dough mix time compared with a bread flour and should have a significantly higher gluten compared with an all‐purpose flour. Compared with bread flour, the tortilla flour had higher retrogradation and viscosity values. The Mixolab profile proved to be a good preliminary test to evaluate flours for hot‐press tortillas.