{"title":"Sarcomere size in developing muscles of a tarsonemid mite.","authors":"J ARONSON","doi":"10.1083/jcb.11.1.147","DOIUrl":null,"url":null,"abstract":"<p><p>The embryo of a tarsonemid mite was found to be suitable for in vivo observations of muscle development by polarization microscopy. The four dorsal muscles of the metapodosoma each contain three sarcomeres, the anterior two of which can be seen clearly. These sarcomeres can be identified and followed during much of their development. Sarcomeres are about 2.5 micra long when first detected and increase in length until they are about 10 micra long. The change in length is associated with a slow, approximately constant rate of increase in the length of the A region, and an initially slow then much more rapid increase in the length of the I band. Preceding the period when the I band elongates rapidly there is an increase in the diameter of the muscle fibers and an increase in the retardation of the A band. A, I, Z, and H bands are visible during most of these changes. The change in A band length has been interpreted in terms of the growth of the A filaments which have been observed by electron microscopy in muscles of other animals. It is suggested that the exceptionally long sarcomeres in this mite result from the early fixing of the number of sarcomeres in a given muscle fiber.</p>","PeriodicalId":22618,"journal":{"name":"The Journal of Biophysical and Biochemical Cytology","volume":"11 ","pages":"147-56"},"PeriodicalIF":0.0000,"publicationDate":"1961-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1083/jcb.11.1.147","citationCount":"42","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Biophysical and Biochemical Cytology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1083/jcb.11.1.147","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 42
Abstract
The embryo of a tarsonemid mite was found to be suitable for in vivo observations of muscle development by polarization microscopy. The four dorsal muscles of the metapodosoma each contain three sarcomeres, the anterior two of which can be seen clearly. These sarcomeres can be identified and followed during much of their development. Sarcomeres are about 2.5 micra long when first detected and increase in length until they are about 10 micra long. The change in length is associated with a slow, approximately constant rate of increase in the length of the A region, and an initially slow then much more rapid increase in the length of the I band. Preceding the period when the I band elongates rapidly there is an increase in the diameter of the muscle fibers and an increase in the retardation of the A band. A, I, Z, and H bands are visible during most of these changes. The change in A band length has been interpreted in terms of the growth of the A filaments which have been observed by electron microscopy in muscles of other animals. It is suggested that the exceptionally long sarcomeres in this mite result from the early fixing of the number of sarcomeres in a given muscle fiber.
用偏振显微镜观察了一种螨的胚胎,发现其适于在体内观察肌肉的发育。后足瘤的4块背肌各包含3个肌节,其中前2个可以清楚地看到。这些肌瘤在其发育过程中可以被识别和跟踪。肌节第一次被发现时大约2.5微米长,长度逐渐增加,直到大约10微米长。长度的变化与a区长度的缓慢,近似恒定的增长速率有关,而I波段长度的增长最初缓慢,后来迅速得多。在I肌束迅速伸长之前,肌纤维直径增加,A肌束迟滞增加。A, I, Z和H波段在这些变化中是可见的。A带长度的变化可以用电子显微镜在其他动物肌肉中观察到的A丝的生长来解释。这表明,在这个螨异常长的肌节是由于早期固定的数量的肌节在一个给定的肌纤维。