Caudal regeneration in the absence of a brain in two species of sedentary polychaetes.

نویسنده

  • S D Hill
چکیده

1. Evidence has been obtained showing that unlike the requirements of errant polychaetes studied by other investigators, at least two species of sedentary polychaetes, Branchiomma nigromaculata and Chaetopterus variopedatus can undergo caudal regeneration in the absence of a brain. 2. Both Branchiomma, when maintained in a brainless condition by repeated removal of anterior segments, and Chaetopterus, when rendered brainless by amputation of cephalic segments at a level at which anterior regeneration does not occur, undergo posterior regeneration following removal of caudal segments. 3. Animals maintained in a brainless condition for 7-10 days prior to posterior segment removal undergo normal posterior regeneration. Consequently, it appears unlikely that a circulating brain hormone present at the time of amputation is responsible. 4. Experiments were performed on the extremely long 13th segment of Chaetopterus. An isolated posterior half of segment 13, which possesses ventral ganglia, regenerates both anteriorly and posteriorly, while the anterior half regenerates only anteriorly. That the tissues of the anterior half of segment 13 are competent to regenerate posteriorly was shown by leaving the anterior half of the segment attached to the first 12 segments. Under these conditions posterior regeneration occurred. 5. These experiments suggest that the ventral ganglia rather than the brain are important in posterior regeneration in these species.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

An assessment of abundance and biological indices of Polychaetes in intertidal zone of Tis Coast - Chabahar Bay

Polychaete worms with high species richness and diversity play a key role in the water food chain. In this research polychates of the intertidal zone of Tis coast in Chabahar bay were studied. Sampling was conducted over a period of one year, from summer to winter 2013 and during four seasons by 50 cm×50 cm quadrats. Twenty two families and 30 genera and 4 species were identified polychaetes.Th...

متن کامل

بررسی وضعیت زادآوری طبیعی در توده‌های بلوط سیاه (Quercus macranthera) در شرایط فیزیوگرافی مختلف در جنگل‌های ارسباران

Natural regeneration ensures the survival of forest stands and sustainable forest development. The present study was conducted to investigate the natural regeneration of Persian oak (Quercus macranthera fisch. & C.A.Mey. Ex Hohen) stands in Arasbaran protected forest. Measurement of the frequency of standard and coppice regenerations was carried out in one-hectare square plots (100 × 100 m) in ...

متن کامل

Effect of exercise training on saliva brain derived neurotrophic factor, catalase and vitamin c

  Background: The balance between production of Reactive Oxygen Species (ROS) and antioxidant defense in the body has important health implications. The aim of this study was to investigate the changes in salivary antioxidants: catalase, vitamin C and brain-derived neurotrophic factor (BDNF), in sedentary men at rest and after acute exhaustive exercise.   Methods: This randomi...

متن کامل

Effect of Stand Structural Characteristics on Natural Regeneration of Acer Campestre L. in Arasbaran Forest

Natural regeneration is one of the key aspects of forest sustainability and a tool to decide on restoration programs in forest areas. The purpose of this study was to investigate the quantity of natural regeneration of Acer campestre L. as one of the most important tree species in Arasbaran forests and its relationship with elevation changes and structural characteristics in the natural stands....

متن کامل

A Comparative Study on Body Shape of the Genus Alburnus (Rafinesque, 1820) in Iran, Using Geometric Morphometric Analysis

Geometric morphometric method was used to examine body shape variations among all the seven valid species of the genus Alburnus in Iran. In total 409 specimens of A. chalcoides, A. filippii, A. atropatenae, A. caeruleus, A. mossulensis, A. hohenackeri and A. zagrosensis were collected from Babolrud, Baleqlu-Chai, Miriseh, Sarabeleh, Gamasiyab, Mahabad-Chai Rivers and the Gandoman lagoon, respec...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of embryology and experimental morphology

دوره 28 3  شماره 

صفحات  -

تاریخ انتشار 1972