No abstract

In mammals, neutrophile polymorphonuclear leukocytes constitute one of the essential body defenses against disease. In a large mammal, such as the dairy cow, billions of neutrophils are mobilized to fight infection. For example, over 50 million neutrophils per milliliter milk are commonly in a mammary quarter inflicted with clinical mastitis. However, in spite of these numerous leukocytes, pathogenic organisms remain viable. Recent evidence indicates that bacteria are not eliminated from a diseased quarter because the phagocytic capacity of the neutrophils is reduced in the mammary gland. The morphology and physiology of the leukocyte is examined in this review in an attempt to explain why the phagocytic capacity of the neutrophil is reduced in the mammary gland of the bovine.

Morphology and distribution of the relatively less well known organelles of plants have been studied with the electron microscope in tissues fixed in glutaraldehyde and postfixed in osmium tetroxide. An organelle comparable morphologically to the animal microbody and similar to the plant microbody isolated by MOLLENHAUER et al. (1966) has been encountered in a variety of plant species and tissues, and has been studied particularly in bean and radish roots, oat coleoptiles, and tobacco roots, stems and callus. The organelle has variable shape and is 0.5 to 1.5 μ in the greatest diameter. It has a single bounding membrane, a granular to fibrillar matrix of variable electron density, and an intimate association with one or two cisternae of rough endoplasmic reticulum (ER). Microbodies are easily the most common and generally distributed of the less well characterized organelles of plant cells. It seems very probable that they contain the enzymes characteristic of animal lysosomes (containing hydrolases) or animal microbodies (containing catalase and certain oxidases). Spherosomes are also possible sites of enzyme activity but are not as common or as widely distributed as microbodies. For this reason it appears likely that the particles designated as "plant lysosomes", "spherosomes", "peroxisomes", etc., in some of the cytochemical and biochemical studies on enzyme localization will prove to be microbodies.Variations in the morphology and ER associations of microbodies in tissues of bean and radish are described and discussed. "Crystal-containing bodies" (CCBs) are interpreted as a specialized type of microbody characteristic of metabolically less active cells. Stages in the formation of CCBs from microbodies of typical appearance are illustrated for Avena.The general occurrence of microbodies in meristematic and differentiating cells and their close association with the ER suggest that they may play active roles in cellular metabolism. The alterations in their morphology and numbers that are observed in certain differentiating cells suggest further that the enzyme complements and metabolic roles of microbodies might change during cellular differentiation. If so, microbodies could be the functional equivalent of both microbodies and lysosomes of animal cells.

Effects of modified pregelatinized potato starch (MPPS) in 5 and 20% fat ground beef patties were evaluated. In formulas containing starch, MPPS comprised 3.0% and added water 5.0% of the raw mixture. Use of 20% rather than 5% fat in the ground beef improved sensory tenderness measured early in chewing, while lowering many Instron measurements. The 20% fat patties had more intense beef flavor. MPPS increased tenderness, but reduced juiciness and beef flavor. The addition (1% of formulation) of concentrated butter flavor to ground beef with MPPS produced beef flavor equivalent to all‐beef patties. The use of MPPS increased cooking yields and moisture content following cooking and reduced fat retention of 20% patties. MPPS increased heating rate while retaining substantial moisture during cooking. Inclusion of MPPS in beef patty formulations offers improvements in tenderness and cooking yield, while reducing fat retention during cooking.