Adherence as a Prerequisite for Infection of the Bovine Mammary Gland by Bacteria

Using a simple in vitro test it was demonstrated that staphylococci, Streptococcus agalactiae, and micrococci, the species of bacteria which are commonly isolated from udder infections, adhered to mammary gland epithelial cells readily and in large numbers. Some strains of organisms which are associated with sporadic outbreaks or occur less commonly, like Str. dysgalactiae and Str. uberis, adhered moderately. Escherichia coli, Klebsiella spp., Corynebacterium pyogenes, C. bovis, Str. bovis, and Str. faecalis, species which are isolated occasionally, adhered poorly. From these studies, it appears that selective adherence of bacteria to the epithelial cells is a factor contributing to the ability of organisms to infect the mammary gland and may, therefore, be considered an important stage in the pathogenesis of bovine mastitis.     

Phosphate flow into mycorrhizal roots

Ectotrophic mycorrhizas have been studied intensively and their value to some tree species is well known. Endotrophic mycorrhizas have received less attention and their potential value to plants has only been fully substantiated within the last 12 years. Responses of the host to mycorrhizal infection seem always to be associated with improved phosphorus nutrition of the plant. The mechanism whereby this occurs is considered. There is evidence that the ultimate limitation on phosphorus uptake by a simple cylindrical root is the diffusion impedance in the soil around it, and that widely spreading hyphae effectively short-circuit this impedance. Some data on hyphal length, and estimated net flux of phosphorus through the hyphae are given, with a discussion of possible mechanisms driving this flux.     

Grain composition of Virginia winter barley and implications for use in feed,food, and biofuels production

Grain compositional components impacting barley (Hordeum vulgare L.) use in food, feed and fuel products, must be combined with improved agronomic traits to produce a commercially viable barley cultivar. Little current information is available on grain composition and variability among winter barley genotypes. This study was conducted to determine the variability among modern hulled and hulless winter barley genotypes in grain composition. Barley types varied significantly in grain and kernel weight, starch, beta-glucan, oil and ash content, but not in protein concentration. Hulless barley had significantly higher grain test weight and starch concentration than hulled and malting types, and significantly higher beta-glucan than malting barley. Hulless barley had significantly lower kernel weights, oil, and ash concentrations than hulled and malting types. Higher starch and lower fiber and ash in grain of hulless barley versus hulled feed or malting type barley are characteristics that increase hulless barley desirability. Selection for high starch concentration among all barley types is feasible and will facilitate development of barley cultivars better suited for use in feed, malt, and ethanol production.     

不同施钾量对冬小麦几个光合特性和产量的影响

 1992～1994年,在滇中山原红壤上所作的田间试验中,冬小麦在3种NP施用水平下施用不同用量的钾肥.研究的初步结果表明,在配施NP肥的基础上,随着施钾量的增加,小麦叶片的气孔阻力减少,提高叶片胞间CO₂浓度和叶绿素含量,增加净光合速率,籽粒产量也有不同程度的增加.     

The fabrication and characterization of the photovoltaic cells composed of polydiacetylene and fullerene

Propargyl alcohol was coupled to 2,4-hexadiyne-1,6-diol (HDD) and crystallized in the process of ultraviolet irradiation-induced topochemical polymerization. The HDD polymer crystals were used as one component in the fabrication of organic photovoltaic cells, in combination with fullerene as the electron acceptor. The various structures of the produced photovoltaic cells included bilayer, trilayer, and bulk heterojunction structures. Their photovoltaic properties were analyzed in relation to crystal structure, electrochemical properties, and band structure of the HDD polydiacetylene polymers.     

Beacon Chipper: A round white chip-processing potato variety

‘Beacon Chipper’ is a high-yielding, round white potato for the chip-processing market. This variety has an attractive round appearance with shallow eyes and high percentage of oversize tubers. Specific gravity in Michigan ranges from 1.077 to 1.083. Beacon Chipper may fit a window in raw product requirements between out-of-the-field ‘Atlantic’ crop and a late storage crop. This variety has some tolerance to common scab (Steptomyces scabies Thaxter) in comparison to Atlantic and ‘Snowden’. Beacon Chipper also has good chip-processing storage characteristics (light color and low amount of defects) and better tolerance to pressure bruise than Snowden. Based upon nitrogen and spacing management studies, we recommend that Beacon Chipper be planted at 20-cm within-row spacing with 180 lbs N/acre to maximize U.S. No. 1 yield and quality. The origin and pedigree of Beacon Chipper is currently unknown, despite extensive fingerprint analyses. The name Beacon Chipper was chosen to reflect the common nautical theme of Michigan and Maine.