Infectious laryngotracheitis virus (ILTV) is the causative agent of a highly contagious upper respiratory tract infection in chickens. At present, ILTV vaccines are not satisfactory because of development of a latent carrier status in vaccinated birds. Development of recombinant virus vaccines has been hampered by the limited information available on the molecular level and organization of this virus. We isolated 3 assembly intermediates, designated A, B, and C from ILTV-infected cells. Analysis of [3H]thymidine- and [35S]methionine-labeled particles, and electron microscopic studies indicated that particle A was the empty capsid, particle B was the procapsid containing scaffolding protein, and particle C was the DNA-filled capsid. The ILTV procapsids could only be found in the nucleus, which indicated that procapsids could not translocate through the nuclear membrane until they packaged the DNA. The DNA-filled capsids migrated through the nuclear membrane and obtained an envelope from the inner membrane of the nucleus. The enveloped particles then migrated through the lumen of the endoplasmic reticulum into vacuoles in the cytoplasm. Infective virions were isolated from within the infected cells, indicating that budding through the cytoplasmic membrane is not a necessary step in ILTV maturation. Abundant arrays composed of tubules about 45 to 50 nm wide were found in the cytoplasm of chicken embryonic liver cells about 30 to 38 hours after infection. Comparison of the assembly intermediates and the DNA packaging pathway of ILTV with that of bacteriophage phi 29 indicates that similarity exists. A model for the pathway of ILTV assembly is proposed.

The aim of this study was to investigate morphological development of filiform papillae (FP) in Korean native goats by using scanning electron microscopy. Tongues were removed from goat fetuses (days 60, 90, and 120), neonates, and juveniles (days 30, 60, 90, 120, 150, and 180 after birth). During the prenatal period, primordia of FP appeared at fetal day 60 and were observed to be developed at day 90. At fetal day 120, the FP were observed like flower leaves of a double flower bud. In neonates, FP were shaped like an obliquely sectioned cylinder with secondary papillae irregularly arranged in a saw blade-like manner. In 60-day-old juvenile goats, the FP were densely distributed at the inner base of 1/3-1/2 degrees. In 90-, 120-, and 150-day-old goats, FP were compacted at the inner base of 1/2-2/3, 3/4, and 4/5 degrees, respectively. In 180-day-old goats, FP were found to be completely compacted on the inner surface with complete morphogenesis. Microridges, microplicae, and micropits were well-developed on the epithelial surface of lingual papillae from embryonic day 120 to juvenile day 180. These results indicate that FP of goats have different shapes and sizes during development both before and after birth.

In dogs, the retina develops during the postnatal period in a manner similar to that in other animals born with closed eyelids. Photoreceptor inner segments are initially observed as a cytoplasmic bulge protruding sclerad through the external limiting membrane. Outer segment formation begins when a centriole within the inner segment attaches to the distal inner segment cell membrane. A few round mitochondria are observed within the early inner segments. As maturation proceeds, the number of mitochondria within the inner segments increases and the mitochondria elongate, orienting parallel to the long axis of the inner segment.

Study of the regeneration processes and raising the efficiency of rape (Brassica napus) organs and tissues cultivation in vitro methods, as well as the achievement of a stable yield of proper regenerants were realized in the conditions of the Republic of Belarus. The obtained data specified the possibility of generation of rape finished regenerants in vitro culture without additional passages and transfers by means of effectively selected concentrations of phytohormones and biologically active substances, which made it possible to realize principles of totipotency and polarity of crop vegetative organs. On the explant part which was submerged into culture medium there was formed a root, and on opposite one - the morphogen structures. The possibility of obtaining rape regenerants from hypocotyls segments by straight regeneration was studied. Application of the analyzed substances considerably simplified and reduced the price of process of full regenerants formation, and made it possible to receive a wide spectrum of various forms that was important for selection process due to the opportunity to select valuable (in protein content) samples for the further studies and their inclusion into production process

In the conditions of the Republic of Belarus there was realized a morphological analysis of pectoral and leg muscles of broiler chickens of cross Cobb-500 in the process of administration of metabolic activator Catosal. Research results showed the positive influence of catosal on the myogenesis: diameter of muscle fiber, the amount of bigger diameter muscles fibers in the first order strand and homogeneity of muscle strands. Under the influence of Catosal preparation there was stated the increasing of the amount of muscle tissue in pectoral and leg parts of chicken carcass. | Приведены данные морфологических исследований грудных и ножных мышц цыплят-бройлеров кросса Кобб-500 при применении активатора метаболизма катозал. Установлено, что катозал активизирует миогенез за счет увеличения диаметра мышечных волокон, содержания в пучках первого порядка мышечных волокон большей толщины, а также большей однородности мышечных пусков. Под действием препарата происходит увеличение содержания мышечной ткани как в грудной части тушки, так и в окороках.