Ultrastructure of Spermatogenesis in the Testis of Paragonimus heterotremus

Lung fluke, Paragonimus heterotremus, is a flatworm causing pulmonary paragonimiasis in cats, dogs, and humans in Southeast Asia. We examined the ultrastructure of the testis of adult P. heterotremus with special attention to spermatogenesis and spermiogenesis using scanning and transmission electron microscopy. The full sequence of spermatogenesis and spermiogenesis, from the capsular basal lamina to the luminal surface, was demonstrated. The sequence comprises spermatogonia, spermatocytes with obvious nuclear synaptonemal complexes, spermatids, and eventual spermatozoa. Moreover, full steps of spermatid differentiation were shown which consisted of 1) early stage, 2) differentiation stage representing the flagella, intercentriolar body, basal body, striated rootlets, and electron dense nucleus of thread-like lamellar configuration, and 3) growing spermatid flagella. Detailed ultrastructure of 2 different types of spermatozoa was also shown in this study.

SEM - Anatomical Studies of Hybrid Silkworm Cocoons.

 This   study  is  designed  and  planned  to  apply  anatomical  knowledge  and  techniques  to  the  problem  imposing  on  the  poor  silk  producer  farmers  in  Thailand.  The  farmers  have  never  been  able  to  set  the  price  for  their  farm  products because  of  several  reasons.  To  sell  their  silkworm  cocoons  is  absolutely  not  an   exception  to  this  agrobsiness  phenomenon.  In  the  annual  meeting  of  the  Institute  of  Sericulture  Research  held  at  Tak  Agricultural  College  in  1989,  the  idea  of  grading  the  size of  reeler  businessmen – the  smaller  the  cheaper  price.  The  problem  was  again  intensified  to  cause  more  deterioration  on  the  farmers’  economy,  and  hence  the  Thai  national  economic  retardation.  The  on  -  going  role  of  the  Institute  of  Sericulture  Research  as  a  referee  or  the  price setter  (by  basing  on  the  weight  ratio  of  the  cocoon  and  the  pupa)  is  considered  by  many  as  a  fair  play.  The  cocoon  size  grading  will  worsen  the  situation  to  a   greater  extent.  If  we  do  not  take  any  action ;  the  situation  would  be  under  the  superior  hands  in  doing  business.  The  farmers,  therefore,  are  exploited  as  always.  By  using  the  Scanning  Electron  Microscopic  Anatomical (SEMAnat)  technique,  we  examined  silk  fiber  mrphology  and  sizes  of  the  small  and  large  cocoons  of  the  hybrid  silkworms  promoted  by  Khon  Kaen  Sericulture  Experiment  Station  in  October  1990. We  have  found  that   the  fiber  sizes  of  the  cocoons  of  different  sizes  are  not  significantly  different  at  500  times  magnification  .  The  size  would  be  dfinitely  the  same  by  the  naked  eyes.  We,  therefore,  concluded  that  as  we  all  know  one  cocoon  is  made  up  of  only  one  single  fiber  of  upto  1500  meters  long,  the  smaller  cocoon  is  made  up  of  one  shorter  fiber  that  will  proportionally  less  than  the  longer  fiber.  The  mass  of  the  silk  fiber  is  governed  by  the  length  in  this  case  and  all  fiber  are  to  join  lengthwise  together  in  the  weaving.  There  is  no  reason  to  be  prejudiced  against  the  smaller  cocoon.  The  cocoon  size  grading  will   be  justified  only  when  we  have  proved  that  the  lrger  cocoons  have  advantage  in  reeling  over  th  small  ones --  this  is  not  the  case.

Ultrastructural Anatomy of Silkgland I. Anterior Part

 The silkglands of the 5th instar larvae of silkworms were dissected under the stereomicroscope.  There are 3 parts to the gland : anterior, straight part; middle, loop-shaped part; and the posterior, coiled part.  The anterior part of the silkglands were processed through the standard technique for the transmission electron microscope for this study.  We found in the columnar cells of this simple tubular gland that it possessed the rough endoplasmic reticulum and a great number of mitochondria.  This finding led us to propose that the anterior part of the gland also synthesized proteins.  We also disclosed that the respiratory tract (air tubes) sent its terminal branches to the gland cell cytoplasm.  This gave proof through our study that both oxygen and harmful things in the air could reach the cytoplasm of silkgland cells quite readily.Key words : silk gland, Bombyx mori, function, ultrastructure.