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[
Worm Breeder's Gazette,
1975]
After hatching, the number of somatic cells in the hermaphrodite of C. elegans increases from about 530 to about 780. The precise lineages which lead to this increase in cell number have been determined by direct observation of developing nematodes. Young worms are mounted on a thin block of agar on a glass slide under a cover slip which contains a small amount of E. coli spread at its center; the edges are sealed with silicone grease or Vaseline to prevent dehydration. When so mounted, the young nematode develops normally and can be observed in the light microscope. Under Nomarski differential interference contrast optics, which detects refractive index variations, nuclei (and often nucleoli) are very distinct and can be followed as they migrate, divide, and, in some cases, die. Using this technique to observe nuclei in developing larvae, we have determined all of the somatic cell lineages which occur after hatching.
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[
Worm Breeder's Gazette,
1982]
We have used pulse labelling and subsequent 2-D gel electrophoresis of newly labelled proteins to answer two questions about the spectrum of proteins synthesized at different times in the lifespan of the worm: Are there changes in the spectrum of proteins synthesized by old worms compared to those synthesized by young adults? Is there misincorporation of amino acids into newly synthesized proteins in old worms? No changes have been detected in the spectrum of proteins synthesized by old as compared to young worms. This finding is in contrast to previous findings (Johnson and Hirsh, 1979) of a large number of changes in the spectrum of proteins synthesized at various times during larval development. Therefore, by this criterion, there appear to be marked differences between the mechanisms operating in development and those that operate to cause aging. We also have found no evidence to suggest that there is an increase in translational errors in old worms. Such an increase might be expected if aging is primarily due to an 'error catastrophe event' somewhere in the information processing machinery of the worm. The generality of these findings is limited by the fact that only the 600-800 most prevalent proteins can be examined by this technique. Furthermore, old worms eat less than young worms, thus lowering the specific activity of the amino acid pool in old worms and consequently decreasing the sensitivity of the assay.
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[
Worm Breeder's Gazette,
1996]
C. elegans (1 - 2 days old) were collected from separate stock, frozen and after 12 hours or more time, thawed, filtrated and mixed with S medium containing E. coli (1:1), this mixture was used as a medium for worms in experimental group. The medium for control group was prepared by mixing S medium containing E. coli with S medium without E. coli (1:1). Three adult animals (3 - 5 days old) were kept in microtitre wells containing 0,75 ml of liquid medium (with E. coli and with or without young worms extract) during 12 hours, then they were discarded and newborn larvae were transferred in next wells every day (one worm in one well). The medium with extract from young worms was used in experimental group beginning from 12th day, that is practically in postreproductive period of nematode life span. A number of progeny was calculated every day. This investigation was carried out in temperature +21C and in the darkness. The obtained results are presented in the following table.
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[
Worm Breeder's Gazette,
1976]
We sometimes want to pick spontaneous males in order to obtain males that, for example, are heterozygous for two closely linked markers in repulsion. If a few young adult hermaphrodites are shifted from their normal growth temperature of 20 C to 27.5 C for 36 hr and then back to 20 C, they will give about 5% male offspring of nearly normal fertility. Heat treatment has been used by others (Nigon, Brenner) to increase the spontaneous male frequency; but this trick may not be common knowledge, so we mention it here.
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[
Worm Breeder's Gazette,
1995]
C. elegans (1 - 2 days old) were collected from separate stock, frozen and after 12 hours or more time, thawed, filtrated and mixed with S medium containing E. coli (1:1), this mixture was used as a medium for worms in experimental group. The medium for control group was prepared by mixing S medium containing E. coli with S medium without E. coli (1:1). Three adult animals (3 - 5 days old) were kept in microtitre wells containing 0,75 ml of liquid medium (with E. coli and with or without young worms extract) during 12 hours then they were discarded and newborn larvae were transferred in next wells every day (one worm in one well). The medium with extract from young worms was used in experimental group beginning from third day, that is in reproductive and postreproductive periods of nematode lie span. Number of progeny was calculated every day. This investigation was carried out in temperature +21 C and in the dark- ness. The obtained results are presented in the following table. ...................................................................... Control group Experimental group n=11 P n=10 Mean+/-S.D. Mean+/-S.D. ......................................................................... Longevity: mean 19,2 +/- 1,9 >0,05 24,2 +/- 2,4 maximal 30 35 minimal 11 11 Period: prereproductive 3,4 +/- 0,3 >0,05 2,9 +/- 0,1 reproductive 10,2 +/- 0,9 <0,05 14,0 +/- 1,3 postreproductive 4,8 +/- 1,2 >0,05 6,9 +/- 1,7 Fecundity: mean 146,8 +/- 10,3 <0,02 199,4 +/-16,2 maximal 182 330 minimal 75 113 ...................................................................... Conclusion: If the extract from young worms was applied to C. elegans during reproductive and postreproductive period of their life span, then it was able to increase their mean fecundity (by 35,8 per cent) as well as length of reproductive period (by 37,3 per cent). The mean longevity in experimental group was slightly increased too (but not significantly). Acknowledgment: The author wishes to express his thanks to CGC for providing C. elegans (Bristol, N2) and E.coli OP50.
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[
Worm Breeder's Gazette,
1977]
A method for fixing and embedding C. elegans eggs will be introduced. It involves prolonged osmium or glutaraldehyde-osmium fixation at elevated temperatures. This procedure works on all stages of embryogenesis. 16 embryos in various stages ranging from an uncleaved zygote to a prehatching 'pretzel' have been serially sectioned. The analysis of a 5-hour embryo with 294 cells and of a 7-hour embryo with 540 cells will be presented. Data from the 5-hour embryo supplement the Nomarski results. Data from the 7-hour embryo will be compared with the anatomy of the young L1 worked out by Sulston and Horvitz.
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[
Worm Breeder's Gazette,
1977]
In liquid phase, the nematode propagates sinusoidal waves along the body, mostly initiated at the anterior end but occasionally at the tail. Although the movement on the agar plate is often stopped, the sinusoidal movement in liquid is rhythmic. The frequency of the wave, which propagates along the body is about 50 per 30 seconds in a young adult at 20 C. The behavior is utilizable for searching chemicals which stimulate or make nervous system paralysis but don't provoke a chemotactic behavior. Caution : I always use synchronously grown worms. Because the movement activity is changeable depending on ages.
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[
Worm Breeder's Gazette,
1977]
In the meeting, some persons were interested by my stained gonads slides. This technical note describes how I proceed to get them. DISSECTED WORMS Fixative = sublimate acetic : 95 ml sublimate (dissolve 10 g of HgCl2 in 100 ml boiling water-let decant one night) and 5 ml acetic acid. When dessication of dissected worms is completed, deposit a fixative drop on the frottis, then immerse the slide in sublimate acetic for 10 mn. Rinse in water and let one (or more) night in iodine-iodized alcohol (100 ml 70% ethanol, 2g I2, 4g KI). Rinse in a 0.25 % sodium hyposulfite solution (5 mn), then in running water (10 mn). Immerse in HCl for 12 mn in a 56 C water-bath, stop hydrolysis by a room temperature water rinse, immerse in Schiff reagent for 2 hours and rinse in running water (15 mn). Stain finally by a fast passing over in : - 1% light green solution, rinse and dehydrate in 1 x 70, 1 x 95, 2 x 100 alcohols, then 2 x Toluene and mount. - picro indigo-carmine (0.25 g indigo-carmine in 100 ml of picric acid aqueous saturated solution). Rinse directly in 100 ethanol ( twice). I prefer use P.I.C. to light green, because the green staining disappears from cytoplasm in 2 to 3 months ENTIRE WORMS (for sections) Fixative = Zenker fluid - stock solution = HgCl2 : 5 g; K2Cr2O7 = 2. 5 g; Na2SO4 = 1g; distilled water 100 ml - Before use, add 5 ml acetic acid. Background staining = Heidenhain's blue - Dissolve in 100 ml hot
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[
Worm Breeder's Gazette,
1978]
We have just completed an EM study of L1 and L2 gonads in hermaphrodite and male worms. Worms were sexed by the presence or absence of the enlarged B cell in the tail before sectioning. Sexing was confirmed by coelomocyte position around the young gonad after sectioning. The major purpose of this study was to see the cytoplasmic boundaries of the gonadal somatic progenitor cells (Z1 and Z4) and their descendants. (The cells in the gonadal primordium are Z1, Z2, Z3, and Z4 from anterior to posterior. Z2 and Z3 are the germ line progenitor cells.) Two findings seem particularly interesting to us. 1) The morphology of young gonads, before Z1 and Z4 divide, is the same in hermaphrodites and males. Z1 possesses a thin cytoplasmic process that extends posteriorly, and Z4 possesses one that extends anteriorly along the ventral surface of the gonad. These processes make contact mid-ventrally. No syncytial interconnection was observed in serial sections of the region where the processes meet. No special junctions were observed between the processes. 2) The somatic cells that occupy the tip positions of the elongating gonadal arms (Z1.aa leads the anterior hermaphrodite arm and Z4.pp leads the posterior hermaphrodite arm; Z1.paa or Z4.aaa leads the single arm in males) have a common ultrastructure. These cells, and only these cells, exhibit distended cisternae of rough ER and an extensive Golgi apparatus. All the other somatic and germ line cells are packed with free ribosomes and mitochondria.
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[
Worm Breeder's Gazette,
1995]
C. elegans (1-2 days old) were collected from separate stock, frozen and after 12 hours or more time thawed, filtrated and mixed with S medium containing E. coli (1:1), this mixture was used as a medium for worms in experimental group. The medium for control group was prepared by mixing S medium containing E. coli with S medium without E. coli (1:1). Three adult animals (3-5 days old) were kept in microtitre wells containing 0,75 ml of liquid medium (with E. coli and with or without young worms extract) during 12 hours, then they were discarded and newborn larvae were transferred in next wells every day (one worm in one well). Number of progeny was calculated every day too. This experiment was carried out in temperature 21 C and in the darkness. The obtained results are presented in the following table. ............................................................... Control group Experimental group n = 12 P n = 11 Mean +/- S.D. Mean +/- S.D. Longevity: mean 24,5 +/- 1,9 <0,001 13,6 +/- 1,5 maximal 36 21 minimal 13 8 Period: prereproductive 3,9 +/- 0,08 <0,05 4,4 +/- 0,2 reproductive 9,9 +/- 0,09 <0,01 6,4 +/- 1,2 postreproductive 9,9 +/- 1,8 <0,001 2,8 +/- 0,7 Fecundity: mean 123,9 +/- 12,7 <O,001 33,6 +/- 7,6 maximal 219 69 minimal 13 o .................................................................. Conclusion: if the extract from young worms was applied to C. elegans during whole life span then it was able to decrease longevity of nematodes, by other words such an extract appeared as toxic, in indicated above conditions. This extract decreased the fecundity too. Acknowledgment: The author wishes to express his thanks to CGC for providing C. elegans (Bristol, N2) and E. coli OP 50.