In avian species, B-lymphocytes develop in the bursa of Fabricius. Cells developing in the bursa are subject to signals regulating their survival, with the majority of cells dying by apoptosis within ...the bursa. However, the molecules delivering the signals influencing this life and death decision remain enigmatic. We have previously shown that antibodies against the chB6 alloantigen present on avian B-lymphocytes can induce a rapid form of cell death. Here we extend this finding by showing that anti-chB6 antibodies induce true apoptosis in DT40 cells without visible membrane damage. This apoptosis results in DNA degradation and morphologic changes characteristic of apoptosis. Furthermore, this apoptosis is coincident with a loss of mitochondrial membrane potential and is inhibited by either overexpression of bcl-x
L or the presence of inhibitors of caspase 8, 9, or 3 activity. Collectively these data argue that chB6 may function as a novel death receptor on avian B-lymphocytes and support the use of DT40 as an amenable model to study the signaling involved in chB6-induced apoptosis.
Electrophilic trisubstituted ethylene monomers, ring-substituted methyl 2-cyano-3-phenyl-2-propenoates, RC
6
H
4
CH˭C(CN)CO
2
CH
3
, (where R is 2-CH
3
O, 3-CH
3
O, 4-CH
3
O, 2-C
2
H
5
O, 3-C
2
H
5
...O, 4-C
2
H
5
O, 4-C
3
H
7
O, 4-C
4
H
9
O, 4-C
6
H
11
O, and 4-CH
3
CO
2
), were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and methyl cyanoacetate, and characterized by CHN elemental analysis, IR,
1
H- and
13
C-NMR. Copolymerization of the propenoates and vinyl acetate in solution with radical initiation (AIBN) at 70°C yielded equimolar alternating copolymers. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR,
1
H and
13
C NMR, GPC, DSC, and TGA. High T
g
of the copolymers in comparison with that of polyvinyl acetate indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 200-400°C range.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Electrophilic trisubstituted ethylenes, ring-disubstituted methyl 2-cyano-3-phenyl-2-propenoates, RCH=C(CN)CO
2
CH
3
(where R = 2,3-dichlorophenyl, 2,4-dichlorophenyl, 2,6-dichlorophenyl, ...3,4-dichlorophenyl, 4-chloro-3-nitrophenyl, 5-chloro-2-nitrophenyl, 2-chloro-6-fluoro),
were prepared and characterized. All the propenoates, except methyl 2-cyano-3-(4-chloro-3-nitrophenyl)-2-propenoate, were copolymerized with styrene (M
1
) in solution with radical initiation (AIBN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis
and the structures were analyzed by IR,
1
H-, and
13
C-NMR. The order of relative reactivity (1/r
1
) for the monomers is 2,4-dichloro (2.1) = 3,4-dichloro (2.1) > 2,6-dichloro (0.8) = 2,3-dichloro (0.8) > 2-chloro-6-fluoro (0.6) > 5-chloro-2-nitro (0.2).
The high glass transition temperatures of the copolymers (> 190°C) in comparison with that of polystyrene indicate a substantial decrease in the chain mobility of the copolymers due to the high dipolar character of the trisubstituted monomer unit. Gravimetric analysis indicated that
the copolymers decompose in the range 300-400°C.
