Koji Ohshima

Cytodifferentiation of the Chick Pineal Gland, With Special Reference to the Photosensory and Secretory Elements

Cytodifferentiation of the chick pineal gland throughout the embryonic development was investigated with light and electron microscopy. The chick pineal anlage appears first as a small evagination in the diencephalic roof at 60 h of incubation (27–30 somites). Until day 5 of incubation, pineal anlage cells are undifferentiated and appear similar to ventricular ependymal cells. Subsequently, pinealocytes and supporting cells are first distinguishable at 7–8 days, and parafollicular cells are distinguishable at 12 days of incubation. Pigment‐containing cells after 6 days and nerve cells after 17 days of incubation gradually increase, especially in the posterior wall of the pineal recess. During embryonic development, the chick pineal gland has both photosen‐sory and secretory elements: viz. the former, mitochondria‐laden apical protrusions, synaptic ribbons, lamellar whorl‐like cilia of the pinealocytes, and adjacent appearance of the pigment‐containing cells and the nerve cells; and the latter, dense‐cored vesicles of the pinealocytes and dense bodies of the supporting cells. Moreover, nuclear invaginations having a large lipid droplet nearby and some aggregations of glycogen are found in the pinealocytes and are transitory changes in structure restricted to certain days of incubation.

Immunohistochemical localization of three different immunoglobulin classes in the Harderian gland of young chickens

The chicken Harderian gland (HG) was investigated using single immunohistochemical staining for one of the three different immunoglobulins (Igs) followed by Alcian blue/periodic acid Schiff (AB/PAS) staining and triple immunohistochemical staining for all of the Igs with hot water treatment. In the HG of 5-week-old chickens, IgG-containing plasma cells were more frequent than IgA- and IgM-containing cells. These numerous IgG-containing cells were predominantly accumulated in the central region of the stroma, whereas a small number of IgA- and IgM-containing cells were scattered in the peripheral region of the stroma. Also, the plasma cells containing PAS-positive Russell bodies (RBs) exhibited distinct immunoreactivity for one of the Igs, being inversely proportional to the intensity of PAS reaction. The RB-containing cells positive for IgA were more frequent than those positive for IgM, whereas those positive for IgG were very rare. The most distinct feature of the IgG-containing plasma cells was a PAS-positive globule located close to the nucleus. Triple immunostaining with hot water treatment simultaneously identified these three Igs in normal plasma cells and RB-containing ones in the stroma of the chicken HG.

Colocalization of NADPH-diaphorase with neuropeptides in the intrapancreatic neurons of the chicken

Colocalization of nitric oxide with neuropeptides was investigated in the chicken pancreas by use of double staining combined with the indirect immunofluorescence technique and histochemistry for NADPH-diaphorase, a specific marker for neural nitric oxide synthase. NADPH-diaphorase positive ganglia were easily detected in the interlobular connective tissue. Many NADPH-diaphorase positive ganglion cells also showed immunoreactivity for VIP (80.9%) or galanin (76.2%). Some ganglion cells showed enzyme activity only (about 20%). Very few neurons were NADPH-diaphorase negative, but immunopositive for VIP (2.0%) or galanin (3.7%). The present study provides evidence that nitric oxide colocates with VIP and galanin in the chicken pancreas.

The Effect of Hunting on the Behavior and Habitat Utilization of Sika Deer (Cervus nippon)

Abstract. The effect of hunting on sika deer (Cervus nippon) was investigated through detailed investigations of their pasture utilization during autumn and winter by using a Global Positioning System (GPS) tracking collar. The study was conducted around a pasture in Nagano Prefecture, Japan. Before the hunting season, while the stockmen stayed in the pasture during the daytime, the collared deer preferred to utilize the pasture during the nighttime. However, at the beginning of the hunting season, the collared deer moved to a precipitous plantation of Japanese larch, located approximately 4 km north-east of the pasture. During the hunting season, the collared deer stayed there and avoided the pasture during the entire day, while after the hunting season, the collared deer preferred to utilize the sunny and clement pasture during the day as there was no human disturbance. These results showed that the behavior and habitat utilization of sika deer were affected by hunting. Thus, it was concluded that sika deer sensed the hunting activities and the presence of humans in the pasture, and altered their behavior to utilize the pasture when it was comparatively safer and more comfortable.

Cytochemical Demonstration of Lysosomes in the Chicken Pineal Gland: Changes Induced by Light‐Dark Cycle

Light and electron microscopic demonstrations for acid phosphatase (AcPase) activity in the chicken pineal gland were studied with special reference to the changes induced by the light—dark cycle. AcPase‐positive lysosomes and Golgi cisternae and vesicles located in the pinealocyte in the light period are well developed and more numerous than in the dark period. In a few cases, a type of lysosome wrapping mechanism is present in the pinealocyte during the light period. Therefore, the lysosomes in the chicken pinealocyte appear active during the light period. In addition, the lysosomes may have functional relationships with the lipid‐like inclusions seen in the dark period.