Coleoptile cuticle of barley is necessary for the increase in appressorial turgor pressure of <Emphasis Type="Italic">Blumeria graminis</Emphasis> for penetration

To determine whether the cuticle of the barley coleoptile is responsible for a rise in appressorial turgor pressure in Blumeria graminis, we determined the appressorial turgor pressure by measuring cytorrhysis and plasmolysis in the presence of PEG6000. Appressorial turgor pressure significantly increased 13–14 h after inoculation. On the other hand, when the cuticle was completely removed from the barley coleoptile surface with diethyl ether, turgor pressure did not increase. Moreover, when we then recoated the surface with the exogenous barley cuticle fraction, appressorial turgor pressure significantly increased 12–13 h after inoculation. These results suggest that the cuticle on the surface of the barley coleoptile is necessary for the increase in the appressorial turgor pressure.     

The Function of Rac Small GTPase and Associated Proteins in Rice Innate Immunity

Two types of innate immune receptors, pattern recognition receptors, and resistance proteins, play crucial roles in plant innate immunity; however, the molecules activated by the receptors and how immune responses are transmitted are not well understood. Evidence has been accumulating for a decade that Rac, a small guanosine triphosphatase (GTPase; also known as Rop) belonging to the Rho-type small GTPase family, is a key regulator of innate immunity in rice, barley, and other species. Like other small GTPases, Rac GTPases function as molecular switches by cycling between GDP-bound inactive and GTP-bound active forms in cells. Rac GTPase acts as a key signaling switch downstream of the two types of immune receptors and triggers innate immunity. This review outlines the role of the Rac family small GTPase and its associated proteins in rice innate immunity.     

Effects of lauric acid on physical, chemical and microbial characteristics in the rumen of steers on a high grain diet

The effects of being fed lauric acid on rumen characteristics were evaluated in a double 3 × 3 Latin square design using six Holstein steers with ruminal cannulas on a high grain diet. The steers were fed commercial concentrate (8.7 kg/day/steer) with one of three levels of lauric acid (0, 25 or 50 g/day/steer) and timothy hay (1.8 kg/day/steer). The feed intake and digestibility were determined. Ruminal fluid was collected at 3 h after feeding to determine chemical, physical and microbial parameters. An in vitro pure culture study was performed to determine the effects of lauric acid on Streptococcus bovis, a potent bloat‐ and acidosis‐promoting rumen bacterium. There were no differences in feed intake and digestibility among the treatments. The proportion of butyrate and the viscosity of the rumen fluid tended to be lowered (P < 0.08 and P < 0.09, respectively) and the stable ingesta volume increase was significantly decreased (P < 0.01) by the lauric acid feed. The abundance of protozoa and bacteria did not differ among the treatments. In the in vitro study, the growth of S. bovis was inhibited by the lauric acid (100 nmol/L) but it showed an adaptive growth to lauric acid in long‐term subculturing. The S. bovis that had adapted to lauric acid showed decreased viscosity and lactate production (P < 0.01) in culture with sucrose. These results indicate that supplemental lauric acid added to a high grain diet improves physical properties, possibly by altering the metabolic activity of S. bovis, and it may prevent the occurrence of feedlot bloat and acidosis in beef cattle.     

Effects of supplemental lauric acid-rich oils in high-grain diet on in vitro rumen fermentation

A series of in vitro studies were performed to evaluate the effects of lauric acid (LA)‐rich oils on rumen fermentation with a high‐grain diet. Soy oil (SO) and palm oil (PO) as long‐chain fatty acid triglycerides, palm kernel oil (PKO), coconut oil (CO), powdered coconut oil (pCO) and coconut oil calcium salt (COCa) as medium‐chain LA‐rich oils were used as tested additives. Rumen fluid from steers fed high‐grain diet was incubated with ground corn with or without oil supplementation (2.0 g/L) for 6 h at 39°C to monitor rumen products. Methane production decreased, while hydrogen production increased on LA‐rich oils except COCa. All the LA‐rich oils increased total volatile fatty acids (VFA) production and molar proportion of propionate. Also, amylase activity in culture was higher when these oils were added. The most potent additives, pCO and free LA, were further tested to determine dose–response of rumen fermentation. Powdered coconut oil and LA altered rumen fermentation toward more propionate production by supplementation at 1.2 and 0.3 g/L, respectively. These results suggest that some LA‐rich oils and free LA could be used for improving rumen fermentation under high‐grain diet feeding conditions.     

Fractionation of grape anthocyanin classes using multilayer coil countercurrent chromatography with step gradient elution

Grape anthocyanins from rosé wine pomace and grape skins were fractionated by multilayer coil countercurrent chromatography (MLCCC). Tert-butyl methyl ether/n-butanol/acetonitrile/water acidified with trifluoroacetic acid (2/2/x/5) was chosen as the solvent system because of its demonstrated efficiency in separating anthocyanins. A method combining MLCCC and step gradient elution has been developed. This method enabled the fractionation of anthocyanins as series of glucosides, and the corresponding acetylated, coumaroylated, and caffeoylated derivatives. The different anthocyanins were identified on the basis of their UV spectra, their elution time on reversed-phase HPLC as well as by mass spectrometry. A polar-colored fraction free of anthocyanin monomers and corresponding to the material remaining in the stationary phase after the completion of the gradient was recovered.     

Mass spectrometric evidence for the existence of oligomeric anthocyanins in grape skins

The fractionation of a grape skin extract by multilayer countercurrent chromatography coupled with step gradient elution allowed the preparation of a fraction almost devoid of free anthocyanins. This fraction appeared to be almost exclusively polymeric, as judged by liquid chromatographic-mass spectrometric (LC-MS) analysis, color-bleaching tests with sulfur dioxide, and thiolysis. Electrospray mass spectrometric analysis indicated that the pigmented material in this fraction was chiefly composed of direct condensation products of anthocyanin extending up to trimers. With regard to their linkages, the anthocyanin units in the oligomers were possibly linked by either an A-type (by both carbon-carbon and ether bonds) or B-type (by carbon-carbon bond) linkage, like proanthocyanidins. The terminal anthocyanin unit of the oligomers is consistently in the flavylium form but the extension units are in the flavan form for the A-type oligomers and in the flavene form for the B-type oligomers. Although their linkages still need to be defined rigorously, this is the first mass spectrometric evidence confirming the existence of anthocyanin oligomers in the grape skin extract.