- Email: [email protected]
Unconventional effects of concanavalin A (Con A) upon amphibian early gastrula ectoderm (EGE) in vitro
252
253
~ C 0 ~ OF CELL INTH~CTIC~S ~URING MAMMALIAN EYE M3RPrILINESIS. B.V. Konyukhov. Institute of Cene_ralGenetics, USSR Academy of Sciences, Moscow, USSR.
PURINE NUCLEOTIDES AND THEIR EFFECTS ON AMBYSTOMA DIFFERENTIATION. M.-O. Mattsson and A. Rehnholm. Dept o f Z o o p h y s l o l o g y , Unlv. o f Ume~, S-901 87 Ume~, Sweden. When the " i n d u c t o r " LiC1 i s added t o c u l t u res of ectodermal explants from late blas-
In our laboratory it was found that the mi locus controls the formation of neural crest derivatives in the mouse. Analysis of interaction of the mi and ~whgenes with the f_i, or and ak genes h a s shown that mi mutant a l l e l e s a f t e r the properties of the ectmm_senchymal c e l l s which, unlike the normal ones, do not possess the melanogenesispromoting and growth-inhibitingactions in retinal pigment epitheliun (RPE). In M~Wh/mi mice a partial nornmiization of the RPE was observed that was due to its interaction with partially normalized ectomesenchyme cells surrounding the optic cup. Using acid ~-~oalactosidaseas a genetic marker we have found in the chinmeric mice RPE re,ions consisting of normally differentiatedMiWh/Mi~h cells and these consisting of abnormally differentiated+/+ cells. This appeared to be due to the inducing fluence of the normal (+/+) and mutant ~_wn/Mi"wn) ectomesenchyme cells, respectively. ~hus, the mi locus acting in the ectomesenchymalcells controls their inductive properties.
tulae of Ambystoma mexicanum a typical repertoire of differentiation patterns including el-cells, nerve cells and ehromatophoFee may be observed. Adenosine phosphates (ATP, ADP, AMP) inhibit this kind of differentiation, in a concentration dependent manner. This inhibition is not obtained with guanosine phosphates (GTP, GDP, GMP), on the contrary these substances alone may "induce" the differentiation and in combination with LiCI they give rise to changes in the morphology of the cells. On the molecular level L i C I , GTP and LiCI+GTP i n c r e a s e the l e v e l o f p r o t e i n s y n t h e s i s , whereas ATP and AMP a l o n e and i n c o m b i n a t i o n w i t h LiC1 have an i n h i b i t i n g e f f e c t . The e f f e c t s o f the nuc l e o t i d e s on RNA s y n t h e s i s do not seem t o correspond t o t h e i r e f f e c t s on d i f f e r e n t i a tion. The c o n t e n t s o f ATP and GTP v a r i e s d u r i n g development, w i t h an i n c r e a s e i n GTP d u r i n g g a s t r u l a t i o n p a r a l l e l l e d by a decrease i n ATP. These f i n d i n g s l e t us propose t h a t the c o n t e n t o£ n u c l e o t l d e s in the embryo i n f l u ences the d i f f e r e n t i a t l o n o f the amphibian b l a s t u l a ectoderm.
2~
255
UNCONVENTIONAL EFFECTS OF CONCANAVALIN A (Con A) UPON A ~ H I B I A N EARLY GASTRULA E C T O D E ~ (EGE) IN VITRO. A . T . M i k h a i l o v and N.A.Gorgclyuk. Institute of D e v e l o p m e n t a l Biology, U S S R Academy of Sciences, ~oscow, USSR.
~iRi'k~CE Ig~i .,d,~D C Y C L I C N J C L E O ~ I D E S OF C].'ICI~N B-LY!JP~OCYT~S IN E } 3 R Y OGEI,i~SIS. 1~is:',anbaev KoN. ~ A l l a ~ a r o v a G.I. ,An~r-eev A o V . , S h p o L j a n s k y Ju.V. I n s t i t u t e of B i o c h e m i s t r y of ~--c::~emy of S c i e n c e s of U z b e k SSRt T a s h k e n t , USSR.
Con A treatment leads t c n e u r a l i z a t i on of Triturus (Takata et al.,1981, 1984) and ~ ( G r ~ n z , 1985; Tacke, Grunz, 1986] gas~rula ectoderm. We studied the d i f f e r e n t i a t i o n of Rana oraria E G E e x p l a n t s treated wi--~ A (50-300 ~g/ml; 3 h, 20°C). The curling of explants was p r e v e n t e d using special weights. The following effects were observed: (I) Neuralization of 50-70% of explants. (2) The formation of "free" lentoids (7-14%) and cartilage (20-50%) in other explants. (3) The frequency of neural and chondral inductions did not correlate with Con A c o n c e n t r a t i o n in culture media. (4) a - m e t h y l - D - m a n n o side inhibited these effects of ConA. (5) S e p h a r o s e - b o u n d Con A showed no specific activity, a l t h o u g h it interacted with inner cells of EGE. (6) Cyclic n u c l e o t i d e s and calcium ionophore A 23187 also possessed no inducing activity.
l i - t h - 1 5 - t h daF of embr~,ogenesis is c L a r a c ~ e r i z e d by the small quan t i t y of surefa~:e Igi~] and by the low c o n t e n t s of c y c l i c n'ccleotides. The ~ i g u i f i c a n ~ i n c r e a s e in cAL~P l e v e l ~ukes ~)iace at 1 5 - t h d a y , a n d cAL~'/cG~F ~ m t i o b e c o m e s r e c i p r o c a l o n e . A ~ ~Sc sa~e time t h e r e is an i~',creusc in qL1antity of s u r e f a c e !g%i~Ig-~h-19-~h day is c i a r u c t e r i ned b~ [;he [~eak of the p r o c e s s men t i o n e d a o o v e . T L e l e v e l s of ~hese s 0 u ~ i e d i n d i c e s a±'e dec~'eased in 1-da~, old c h i c k e n s . ~'lius~olle Cdn Hl~ke d c o n c l u s i o n a b o u t c}'clic and S~'l]Ch~?onic o n t o c o n e tic d e t e r m i n a t i o n of chicl~en e m b r y o B-lym{~l~.oc~es w i t h the p e a k oi' the a c t i v i t y of d i f f e r e n t i a t i o n at 1 7 - t h - q g - S h day of v m b ~ ' o g e n e di~°
~o~p
90S
253
~ C 0 ~ OF CELL INTH~CTIC~S ~URING MAMMALIAN EYE M3RPrILINESIS. B.V. Konyukhov. Institute of Cene_ralGenetics, USSR Academy of Sciences, Moscow, USSR.
PURINE NUCLEOTIDES AND THEIR EFFECTS ON AMBYSTOMA DIFFERENTIATION. M.-O. Mattsson and A. Rehnholm. Dept o f Z o o p h y s l o l o g y , Unlv. o f Ume~, S-901 87 Ume~, Sweden. When the " i n d u c t o r " LiC1 i s added t o c u l t u res of ectodermal explants from late blas-
In our laboratory it was found that the mi locus controls the formation of neural crest derivatives in the mouse. Analysis of interaction of the mi and ~whgenes with the f_i, or and ak genes h a s shown that mi mutant a l l e l e s a f t e r the properties of the ectmm_senchymal c e l l s which, unlike the normal ones, do not possess the melanogenesispromoting and growth-inhibitingactions in retinal pigment epitheliun (RPE). In M~Wh/mi mice a partial nornmiization of the RPE was observed that was due to its interaction with partially normalized ectomesenchyme cells surrounding the optic cup. Using acid ~-~oalactosidaseas a genetic marker we have found in the chinmeric mice RPE re,ions consisting of normally differentiatedMiWh/Mi~h cells and these consisting of abnormally differentiated+/+ cells. This appeared to be due to the inducing fluence of the normal (+/+) and mutant ~_wn/Mi"wn) ectomesenchyme cells, respectively. ~hus, the mi locus acting in the ectomesenchymalcells controls their inductive properties.
tulae of Ambystoma mexicanum a typical repertoire of differentiation patterns including el-cells, nerve cells and ehromatophoFee may be observed. Adenosine phosphates (ATP, ADP, AMP) inhibit this kind of differentiation, in a concentration dependent manner. This inhibition is not obtained with guanosine phosphates (GTP, GDP, GMP), on the contrary these substances alone may "induce" the differentiation and in combination with LiCI they give rise to changes in the morphology of the cells. On the molecular level L i C I , GTP and LiCI+GTP i n c r e a s e the l e v e l o f p r o t e i n s y n t h e s i s , whereas ATP and AMP a l o n e and i n c o m b i n a t i o n w i t h LiC1 have an i n h i b i t i n g e f f e c t . The e f f e c t s o f the nuc l e o t i d e s on RNA s y n t h e s i s do not seem t o correspond t o t h e i r e f f e c t s on d i f f e r e n t i a tion. The c o n t e n t s o f ATP and GTP v a r i e s d u r i n g development, w i t h an i n c r e a s e i n GTP d u r i n g g a s t r u l a t i o n p a r a l l e l l e d by a decrease i n ATP. These f i n d i n g s l e t us propose t h a t the c o n t e n t o£ n u c l e o t l d e s in the embryo i n f l u ences the d i f f e r e n t i a t l o n o f the amphibian b l a s t u l a ectoderm.
2~
255
UNCONVENTIONAL EFFECTS OF CONCANAVALIN A (Con A) UPON A ~ H I B I A N EARLY GASTRULA E C T O D E ~ (EGE) IN VITRO. A . T . M i k h a i l o v and N.A.Gorgclyuk. Institute of D e v e l o p m e n t a l Biology, U S S R Academy of Sciences, ~oscow, USSR.
~iRi'k~CE Ig~i .,d,~D C Y C L I C N J C L E O ~ I D E S OF C].'ICI~N B-LY!JP~OCYT~S IN E } 3 R Y OGEI,i~SIS. 1~is:',anbaev KoN. ~ A l l a ~ a r o v a G.I. ,An~r-eev A o V . , S h p o L j a n s k y Ju.V. I n s t i t u t e of B i o c h e m i s t r y of ~--c::~emy of S c i e n c e s of U z b e k SSRt T a s h k e n t , USSR.
Con A treatment leads t c n e u r a l i z a t i on of Triturus (Takata et al.,1981, 1984) and ~ ( G r ~ n z , 1985; Tacke, Grunz, 1986] gas~rula ectoderm. We studied the d i f f e r e n t i a t i o n of Rana oraria E G E e x p l a n t s treated wi--~ A (50-300 ~g/ml; 3 h, 20°C). The curling of explants was p r e v e n t e d using special weights. The following effects were observed: (I) Neuralization of 50-70% of explants. (2) The formation of "free" lentoids (7-14%) and cartilage (20-50%) in other explants. (3) The frequency of neural and chondral inductions did not correlate with Con A c o n c e n t r a t i o n in culture media. (4) a - m e t h y l - D - m a n n o side inhibited these effects of ConA. (5) S e p h a r o s e - b o u n d Con A showed no specific activity, a l t h o u g h it interacted with inner cells of EGE. (6) Cyclic n u c l e o t i d e s and calcium ionophore A 23187 also possessed no inducing activity.
l i - t h - 1 5 - t h daF of embr~,ogenesis is c L a r a c ~ e r i z e d by the small quan t i t y of surefa~:e Igi~] and by the low c o n t e n t s of c y c l i c n'ccleotides. The ~ i g u i f i c a n ~ i n c r e a s e in cAL~P l e v e l ~ukes ~)iace at 1 5 - t h d a y , a n d cAL~'/cG~F ~ m t i o b e c o m e s r e c i p r o c a l o n e . A ~ ~Sc sa~e time t h e r e is an i~',creusc in qL1antity of s u r e f a c e !g%i~Ig-~h-19-~h day is c i a r u c t e r i ned b~ [;he [~eak of the p r o c e s s men t i o n e d a o o v e . T L e l e v e l s of ~hese s 0 u ~ i e d i n d i c e s a±'e dec~'eased in 1-da~, old c h i c k e n s . ~'lius~olle Cdn Hl~ke d c o n c l u s i o n a b o u t c}'clic and S~'l]Ch~?onic o n t o c o n e tic d e t e r m i n a t i o n of chicl~en e m b r y o B-lym{~l~.oc~es w i t h the p e a k oi' the a c t i v i t y of d i f f e r e n t i a t i o n at 1 7 - t h - q g - S h day of v m b ~ ' o g e n e di~°
~o~p
90S