Utsunomiya University

About: Utsunomiya University is a education organization based out in Utsunomiya, Japan. It is known for research contribution in the topics: Laser & Holography. The organization has 4139 authors who have published 6812 publications receiving 91975 citations. The organization is also known as: Utsunomiya daigaku.

Germination response of Orobanche seeds subjected to conditioning temperature, water potential and growth regulator treatments

Abstract: Broomrapes (Orohanche spp.) are parasitic weeds that cause significant losses of crop yield. Experiments were conducted to investigate the seed response to the artificial germination stimulant GR 24 in three species of Orobanche subjected to preconditioning under various temperatures, water potentials and with plant growth regulators. The highest germination percentages were observed in Orobanche ramosa, Orohanche aegyptiaca and Orohanche minor seeds conditioned at 18°C for 7 days followed by germination stimulation at 18°C. With the increase of the conditioning period (7, 14, 21 and 28 days), the germination percentage of O. ramosa and O. aegyptiaca progressively decreased. When conditioned at -2 MPa, the germination percentage was lower than at 0 and -1 MPa, especially at 13 and 28°C. Orohanche minor seeds could retain relatively high germination if conditioned at 18, 23 or 28°C, even after significantly extended conditioning periods (up to 84 days). GA 3 (30-100 mg L -1 ), norflurazon and fluridone (10-100 mg L -1 ), and brassinolide (0.5-1.0 mg L -1 ) increased seed germination, while 0.01 mg L -1 uniconazole significantly reduced germination rates of all three Orobanche spp. The promotional effects of GA 3 and norflurazon and the inhibitory effect of uniconazole were evident, even when they were treated for 3 days. Germination of Orobanche seeds was much lower when the unconditioned seeds were directly exposed to GR 24 at 10 -6 M. This early GR 24 -induced inhibition was however alleviated or even eliminated by the inclusion of GA 3 or norflurazon (10-50 mg L -1 ) in the conditioning medium. On the contrary, the inclusion of uniconazole increased the inhibitory effect of GR 24 , particularly in the case of O. ramosa.

Secretory membranes of the lactating mammary gland.

Abstract: The lactating mammary gland is one of the most highly differentiated and metabolically active organs in the body. Membranes of the lactating mammary cell have important roles in transmitting from one membrane to another of hormonal information and in milk secretion, which is the final event. During milk secretion, the projection of the surface membrane into the alveolar lumen by enveloping intracellular lipid droplets with the apical plasma membrane is one of the most remarkable aspects of biological membrane action throughout nature. This review focuses on current knowledge about membranes in the lactating mammary gland. (1) Advances in the isolation and properties of membranes, especially the plasma membrane and Golgi-derived secretory vesicles, concerned with milk secretion from the lactating mammary gland are described. (2) Milk serum components are secreted by fusing the membranes of secretory vesicles that condense milk secretions with the plasma membrane in the apical regions. This occurs through the formation of a tubular-shaped projection and vesicular depression in a ball-and-socket configuration, as well as by simple fusion. (3) Intracellular lipid droplets are directly extruded from the mammary epithelial cells by progressive envelopment of the plasma membranes in the apical regions. (4) The balance between the surface volume lost in enveloping lipid droplets and that provided by fusion of the secretory vesicle and other vesicles with the apical plasma membrane is discussed. (5) The membrane surrounding a milk fat globule, which is referred to as the milk fat globule membrane (MFGM), is composed of at least the coating membrane of an intracellular lipid droplet, of the apical plasma membrane and secretory vesicle membrane, and of a coat material. Consequently, MFGM is molecularly different from the plasma membrane in composition. (6) MFGM of bovine milk is structurally composed of an inner coating membrane and outer plasma membrane just after segregation. These two membranes are fused and reorganized through a process of vesiculation and fragmentation to stabilize the fat globules. Hypothetical structural models for MFGM from bovine milk fat globules just after secretion and after rearrangement are proposed.