ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04459.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04460.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04461.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SYNOPSISThe mitochondria occur as granules and short rods throughout the various developmental stages of the locust. No filamentous mitochondria could be detected. In early germ‐band cells the mitochondria exist as small granules and very short rods scattered in the cytoplasm. They are shared out between the dividing neuroblasts, and remain as such in the early ganglion cells and in the first four nymphal instars.The nerve cells of the fifth instar nymph (as well as the large neurones of the fourth instar nymph) and adult locust contain, besides the normal mitochondria, a number of swollen bodies which we consider as metamorphosed mitochondria. The latter type, in old neurones, decreases in number and moves towards the cell periphery.In the senile condition the metamorphosed mitochondria are no longer visible.The pictures of mitochondria in living unstained or vitally stained preparations do not differ from those of fixed and stained materials.The mitochondria are not responsible for the production of the Golgi dictyosomes as an effect of fixation and metallic impregnation, as is shown from the following:(a) In the early germ‐band cells, a single osmiophilic globule (Golgi body) is found, whereas the mitochondria appear in the form of many small granules and very short rods scattered in the cytoplasm.(b) In the early developmental stages, the mitochondria are evenly scattered in the cytoplasm, whereas the Golgi dictyosomes are polarized.(c) The mitochondria and dictyosomes can be demonstrated side by side in the

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04462.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SYNOPSISThe histology and fine anatomy of the larva ofBolitophila luminosahave been considered. There are two separate glands, silk (salivary) and mucus, producing the web and mucus droplets of the snare. Chordotonal (scolophore) organs have been described from the anal papillæ

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04463.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SYNOPSISLengths of the spinal cord of young larvæ ofXenopuswere grafted into the ventral body wall of host tadpoles of the same age, together with the adjacent somites and notochord. The experimental animals were fixed at various times after the operation, and the grafts were studied in serial sections.The dorsal root ganglia of the grafts underwent little development. Some were suppressed, and there were instances of the fusion of neighbouring ganglia. The greater part of each ganglion was occupied by a mass of undifferentiated neuroblasts, sometimes present in greater numbers than the total of cells in a normal ganglion. In most specimens it was possible to identify the individual ganglia and hence to determine the levels to which the grafted cord belonged.Within the cord the only differentiated neurones were the primary motor cells from which arose ventral roots, dendritic processes, and ventral commissural fibres as in a normal early larva. Dorsal roots enter the cord in a normal fashion, and give off ascending and descending branches. At the caudal pole of the graft the cord regenerated, and some new irregular myotomes were formed.The mantle layer of the cord expanded laterally and underwent a hyperplasia of about twofold in terms of number of cells per spinal segment. The large neuroblastic dorsal horn is prominent, even in instances where there are no dorsal root ganglia. As in previous experiments where the cord is deprived of any influence of the limb buds, there are no differentiated ventral horn cells. The absence of all mature neurones within the mantle layer is a further feature which suggests that the stimuli for their differentiation in normal development proceed not only from the limb but also from the spinal axis.In contrast to the normal cord of late larval stages, no pycnotic nuclei can be seen within the mantle layer of the grafts. It is possible that its cellular hyperplasia is in part due to the absence of histogenetic degeneration

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04464.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SYNOPSISThe sperm ofPetrobius maritimusis a normal flagellate type and is formed in the normal manner. The acrosome is a clearly marked and easily followed structure. In the final stages the acrosome can be seen to be deposited on the proximal end of the nucleus as a composite structure with a small granule at the tip. It is a secretory product of the Golgi body and not the Golgi body itself. The spent acroblast (dictyosome, Golgi body) drifts down the lengthening spermatid as the acroblast reject, as normally occurs in flagellate spermiogenesis. The centriole region probably consists of the centriole plus the centriole adjunct, but is too small to be resolved by the light microscope. The mitochondrial nebenkern is formed by the aggregation, but apparently not the agglutination, of the mitochondria, and is not typical of the mitochondrial nebenkern of holometabolous insects.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04465.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

Book reviewed in this article:Elektronenmikroskopische Untersuchungs‐ und Präparationsmethoden.—ludwigReimerTools of Biological Research.—Edited HedleyJ. B. AtkinsLaboratory Instruments—Their Design and Application.—A. Elliottand J. HomeDicksonFrontiers in Cytology.—Edited SanfordS. PalayAn Introduction to Genetics.—C. M. M. BeggCrystals and the Polarizing Microscope.—N. H. Hartshorneand A. StuartMeasuring the Invisible Wor

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1959.tb04466.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY