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An endogenous component of the mechanism controlling the vitellogenic cycle in the American cockroach
J. Insect Physiol.,
1977. Vol. 23, pp. 895 to 897. Pergamorl
Press. Printed in Great Britain.
AN E:NDOGENOUS COMPONENT OF THE MECHANISM CONTROLLING THE VITELLOGENIC CYCLE IN THE AMERICAN COCKROACH WILLIAM C.-J. MAA and WILLIAM J. BELL Department of Entomology and Department of Physiology and Cell Biology, Umverstty of Kansas. Lawrence, Kansas 66045. U.S.A. (Received
5 February
1977)
Abstract--The continuous and rhythmic vitellogenic cycle of an oviparous cockroach, Periplaneta americana. is controlled at least in part by an endogenous “clock-like” mechanism within ovarian follicles. 24 hr after adult emergence dually in 250ml containers.
I VTRODUCTION FEMALES of the American cockroach, Periplunrtu urnr~icaf~a, deposit their first oothecae about 12 days after adult ecdysis: thereafter oiithecae are deposited every 5 days (MILLS et al.. 1966; BELL, 1969a). As in other cockroaches, the initiation of vitellogenesis is controlled by juvenile hormone (JH) secreted by the corpora allata. Juvenile hormone in cockroaches triggers secretion of female-specific yolk precursors (vitellogenins) by the fat body (Paw et u1., 1969; ENGELMANN, 1969 ; BROOKS, 1969; WYSS-H~~BERand L~~SCHER.1972) and the uptake of vitellogenins by the oijcytes (BELL and BARTH, 1971: BELL and SAMS. 1977).
In some viviparous and ovoviviparous cockroaches there is a cyclic inhibition of corpora allata activity during the gestation period (ENGELMANN.1970). This inhibitory mechanism probably involves a negative feedback from the uterus to the corpora allata, since cautery of the nervi allati activates the corpora allata and stimulates yolk deposition (ENGELMANN. 1970). Because P. umericcma. as well as other oviparous species of cockroaches, has a continuous vitellogenic cycle with no gestation period (BELL, 1969a), and in which the penultimate oocyte is engaged in yolk deposition at the same time as the basal oocyte. periodic curtailment of JH secretion seems not to be a plausible mechanism for regulation of the vitellogenic cycle in the specie:j. The question therefore arises as to what mechanism controls the vitellogenic cycle of an oviparous cockroach such as P. americana. MATERIALS
AND
Trunsplantation
and were housed
indivi-
techniques
Ovarioles to be transplanted were dissected into cockroach salone (VAN ASPERENand VAN ESCH, 1956). Host insects were anesthetized with CO,, and implants injected into the abdomen through the intersegmental membrane between dorsal segments 5 and 6 with a Gilmont microsyringe (BELL. 1972a, b). The wound was sealed with paraffin and 10 to 15 ~1 of lo.; streptomycin was injected into the host through the tibia-femur joint. Implanted ovarioles, and ovarioles of the host were later examined for yolk deposition under a binocular microscope. Criteria used for determination of yolk formation were (1) increase in oocyte volume, and (2) presence of refractile yolk spheres in the cortex of oocytes (BELL, 1969b).
RESULTS The following experiments were carried out to determine if the vitellogenic cycle is controlled by information transferred from posterior to anterior oocytes which might inhibit or stimulate development of the more anterior oiicytes. Removal of the posterior oiicytes might be expected to stimulate precocious vitellogenesis in anterior oiicytes. Therefore, posterior oiicytes were surgically removed in saline as depicted in Table 1. and the altered ovarioles were transplanted to recipients in the same stage of the 5-day vitellogenic cycle as donors. Rectpients were dissected 5, 10, 15, or 20 days later, the days on which ovulation normally occurs. The results (Table 1) show that posterior oiicytes do not inhibit vitellogenic competence in the more anterior oiicytes; more surprising, the results illustrate that each oocyte initiates vitellogenesis on the day on which this process normally would be predicted to begin When ovarioles were transected as above and transplanted, but then removed before the expected
METHODS
Insect material Colonies of P. wwricanu used in this study were housed in cages under controlled environmental conditions with a constant temperature of 26C and 75T0 r.h. Purina laboratory chow and water were available ctd Iihitucr. All cockroaches used in the experiments were removed from colony cages within 895
896
WILLIAM C.-J. MAA Table
1. Transplantation
OGcytes excised from donor females 1 2 3 4 5 6 A.
B.
C.
00.0.. o/o 0 0 0 0 010 0 0 0 0 010 0 0 0 0 010
0 0 0 0
0
010
0
0 0
0 0
0 0 00.0.. 00.0.. 0 0
AND
WILLIAM J. BELL
of excised ovarioles
Period Cycles
N
females* Pattern of yolk deposition in oiicytes of transplanted ovarioles 23456189 00.000.. 00.000.. 0.000..
1 1
5 5 5 5 5
30 30 16 20 17
0
2
10
010 0 0 010
0 0
2 2
10 10
16 20 15
00.00.. 0.00.. 0
.I@
0
3 3 4 4
15 15 20 20
11 15 12 16
00e.0. 0
0
0
0
0
1 1
of incubation Days
to vitellogenic
1
010
* Symbols used: 0, vitellogenic oBcytes: 0, non-vitellogenic all representations of ovarioles. posterior oiicytes are toward
time of initiation of yolk tion was observed.
deposition,
no yolk
deposi-
l
.0.e. 0 0
0
0
0
0
0
0
0
0 0
0 0 0
0 0 0
0 0
oiicytes; /, locus of excision before transplantation. the left, anterior oiicytes toward the right.
.4ckflowlrdyrmrrlrs-This research was supported University of Kansas Biomedical Sciences Support (RR-07037) and a grant from the National Science dation (PCM76-02229).
l
In
by a Grant Foun-
lbISCUSSION
In the ovariole transplant experiments presented here the temporal sequence of successive initiation of oBcyte vitellogenesis was maintained. Removal of posterior oiicytes did not cause precocious yolk deposition in anterior oijcytes. The most plausible explanation which is consistant with the results is that each ovarian follicle has an endogenous “clock” which regulates development of the follicle. This suggests a pre-programming within the ovariole. Perhaps a rigid sequence is already established at adult ecdysis, in which each oijcyte is developmentally 5 days behind the next most posterior oiicyte. This is unlikely, however, since environmentally or experimentally-induced inhibition of vitellogenesis would require a mechanism for maintaining each oijcyte in its respective temporal developmental sequence. Such a hiatus occurs when female cockroaches are starved; juvenile hormone secretion is inhibited, yolk deposition is curtailed, and vitellogenic oiicytes are resorbed in P. arfWcana (BELL. 197 1; BELL and BOHM, 1975) or arrested in Blatta arierltalis (SAMS, 1975). During the period of starvation, if a rigid sequence of oiicyte development were the case, then each o6cyte would have to cease further development and “mark time” until feeding re-initiated secretion of juvenile hormone and ensuing vitellogenic cycles. Thus. the proposed ovariole “clock” must be modulated by some extra-ovarian factor(s) which are at present not known. The “clock” and its modulators must govern a vitellogenic cycle which normally is continuous but subject to periods of vitellogenic arrest.
REFERENCES ASPAREN K. VAN and ESCH 1. VAN (1956) The chemical composition of haemolymph in Prriplanr~a uttleric~~~~u with special reference to the mineral constituents. .4r(h. r~e,rrl. Zoo/. 11. 342-360. BELL W. J. (1969a) Continuous and rhythmic reproductive cycle observed in Periplarzeta americana. Biol. Bull.. Woods Hole 137. 239-249. BELL W. J. (1969b) Dual rble of juvenile hormone in the control of yolk formation in Periplaneta umrricanu. J. Ifwct Physiol. 15. 1279-I 290. BELL W. J. (1971) Starvation-induced oijcyte resorption and yolk salvage in Periplarteta americana. J. Insrct Physiol. 17. 1099~1111. BELL W. J. (1972a) Transplantation of ovaries into male Periplaneta affwricaffa: effects on vitellogenesis and vitellogenin secretion. J. Insecr Physiol. 18, 851~855. BELL W. J. (1972b) Yolk formation by transplanted cockroach oiicytes. J. exp. 2001. 181, 41-48. BELL W. J. and BARTH R. H. JR. (1971) Juvenile hormoneinitiation of yolk deposition in a cockroach. Nature. N.B.. Land. 230. 220-221. BELL W. J. and SAMS G. R. (1977) Juvenile hormone control of yolk deposition in the American cockroach in vitro. Gen. conlp. Endocr. In press. BELL W. J. and BOHM M. K. (1975) Oosorption in insects. Biol. Rec. SO. 373-396. BRO~KES V. J. (1969) The induction of yolk protein synthesis in the fat body of an insect, Leucophaea maderae, by an analogue of the juvenile hormone. Devel. Biol. 20, 459-47 1. ENGELMANN N. F. (1969) Female specific protein: biosynthesis controlled by corpus allatum in Leucophueu maderae. Science, Wash. 165, 407-409.
Vitellogenic
cycle in the American
ENGEL~NN F. (19’Q T/w f%)smiog~ of’ lusrrl Rqvotiw tion 44. Internal :;eries monographs in pure and applied biology. Pergamon Press, New York. MILLS R. R., GREEI~SLADE F. C., and COIXH E. F. (1966) Studies on vitellogenesis in the American cockroach. J. It~srct Physiol. 12. 761-179. PAN M. L.. Bt1.1. W. J.. and TI:I.FER W. H. (1969) Vitello-
cockroach
897
gemc blood protein synthesis by inset fat bady. Sci~wr,. M/C&T.165. 393-394. SAMS G. R. (1975) Vitellogenic arrest in the cockroach. Bkmn orirrttulis. J. If7.swt Pl~~siol. 21. 1103% I71 0. WYSS-H~BER M. and L~:SCHEK M. (1972) III ritro synthesis and release of proteins by fat body and ovarian tissue of LCUL~O~/IIIPU. J. I/~wct Ph \xiol. 18. 6X9- 7 IO.
1977. Vol. 23, pp. 895 to 897. Pergamorl
Press. Printed in Great Britain.
AN E:NDOGENOUS COMPONENT OF THE MECHANISM CONTROLLING THE VITELLOGENIC CYCLE IN THE AMERICAN COCKROACH WILLIAM C.-J. MAA and WILLIAM J. BELL Department of Entomology and Department of Physiology and Cell Biology, Umverstty of Kansas. Lawrence, Kansas 66045. U.S.A. (Received
5 February
1977)
Abstract--The continuous and rhythmic vitellogenic cycle of an oviparous cockroach, Periplaneta americana. is controlled at least in part by an endogenous “clock-like” mechanism within ovarian follicles. 24 hr after adult emergence dually in 250ml containers.
I VTRODUCTION FEMALES of the American cockroach, Periplunrtu urnr~icaf~a, deposit their first oothecae about 12 days after adult ecdysis: thereafter oiithecae are deposited every 5 days (MILLS et al.. 1966; BELL, 1969a). As in other cockroaches, the initiation of vitellogenesis is controlled by juvenile hormone (JH) secreted by the corpora allata. Juvenile hormone in cockroaches triggers secretion of female-specific yolk precursors (vitellogenins) by the fat body (Paw et u1., 1969; ENGELMANN, 1969 ; BROOKS, 1969; WYSS-H~~BERand L~~SCHER.1972) and the uptake of vitellogenins by the oijcytes (BELL and BARTH, 1971: BELL and SAMS. 1977).
In some viviparous and ovoviviparous cockroaches there is a cyclic inhibition of corpora allata activity during the gestation period (ENGELMANN.1970). This inhibitory mechanism probably involves a negative feedback from the uterus to the corpora allata, since cautery of the nervi allati activates the corpora allata and stimulates yolk deposition (ENGELMANN. 1970). Because P. umericcma. as well as other oviparous species of cockroaches, has a continuous vitellogenic cycle with no gestation period (BELL, 1969a), and in which the penultimate oocyte is engaged in yolk deposition at the same time as the basal oocyte. periodic curtailment of JH secretion seems not to be a plausible mechanism for regulation of the vitellogenic cycle in the specie:j. The question therefore arises as to what mechanism controls the vitellogenic cycle of an oviparous cockroach such as P. americana. MATERIALS
AND
Trunsplantation
and were housed
indivi-
techniques
Ovarioles to be transplanted were dissected into cockroach salone (VAN ASPERENand VAN ESCH, 1956). Host insects were anesthetized with CO,, and implants injected into the abdomen through the intersegmental membrane between dorsal segments 5 and 6 with a Gilmont microsyringe (BELL. 1972a, b). The wound was sealed with paraffin and 10 to 15 ~1 of lo.; streptomycin was injected into the host through the tibia-femur joint. Implanted ovarioles, and ovarioles of the host were later examined for yolk deposition under a binocular microscope. Criteria used for determination of yolk formation were (1) increase in oocyte volume, and (2) presence of refractile yolk spheres in the cortex of oocytes (BELL, 1969b).
RESULTS The following experiments were carried out to determine if the vitellogenic cycle is controlled by information transferred from posterior to anterior oocytes which might inhibit or stimulate development of the more anterior oiicytes. Removal of the posterior oiicytes might be expected to stimulate precocious vitellogenesis in anterior oiicytes. Therefore, posterior oiicytes were surgically removed in saline as depicted in Table 1. and the altered ovarioles were transplanted to recipients in the same stage of the 5-day vitellogenic cycle as donors. Rectpients were dissected 5, 10, 15, or 20 days later, the days on which ovulation normally occurs. The results (Table 1) show that posterior oiicytes do not inhibit vitellogenic competence in the more anterior oiicytes; more surprising, the results illustrate that each oocyte initiates vitellogenesis on the day on which this process normally would be predicted to begin When ovarioles were transected as above and transplanted, but then removed before the expected
METHODS
Insect material Colonies of P. wwricanu used in this study were housed in cages under controlled environmental conditions with a constant temperature of 26C and 75T0 r.h. Purina laboratory chow and water were available ctd Iihitucr. All cockroaches used in the experiments were removed from colony cages within 895
896
WILLIAM C.-J. MAA Table
1. Transplantation
OGcytes excised from donor females 1 2 3 4 5 6 A.
B.
C.
00.0.. o/o 0 0 0 0 010 0 0 0 0 010 0 0 0 0 010
0 0 0 0
0
010
0
0 0
0 0
0 0 00.0.. 00.0.. 0 0
AND
WILLIAM J. BELL
of excised ovarioles
Period Cycles
N
females* Pattern of yolk deposition in oiicytes of transplanted ovarioles 23456189 00.000.. 00.000.. 0.000..
1 1
5 5 5 5 5
30 30 16 20 17
0
2
10
010 0 0 010
0 0
2 2
10 10
16 20 15
00.00.. 0.00.. 0
.I@
0
3 3 4 4
15 15 20 20
11 15 12 16
00e.0. 0
0
0
0
0
1 1
of incubation Days
to vitellogenic
1
010
* Symbols used: 0, vitellogenic oBcytes: 0, non-vitellogenic all representations of ovarioles. posterior oiicytes are toward
time of initiation of yolk tion was observed.
deposition,
no yolk
deposi-
l
.0.e. 0 0
0
0
0
0
0
0
0
0 0
0 0 0
0 0 0
0 0
oiicytes; /, locus of excision before transplantation. the left, anterior oiicytes toward the right.
.4ckflowlrdyrmrrlrs-This research was supported University of Kansas Biomedical Sciences Support (RR-07037) and a grant from the National Science dation (PCM76-02229).
l
In
by a Grant Foun-
lbISCUSSION
In the ovariole transplant experiments presented here the temporal sequence of successive initiation of oBcyte vitellogenesis was maintained. Removal of posterior oiicytes did not cause precocious yolk deposition in anterior oijcytes. The most plausible explanation which is consistant with the results is that each ovarian follicle has an endogenous “clock” which regulates development of the follicle. This suggests a pre-programming within the ovariole. Perhaps a rigid sequence is already established at adult ecdysis, in which each oijcyte is developmentally 5 days behind the next most posterior oiicyte. This is unlikely, however, since environmentally or experimentally-induced inhibition of vitellogenesis would require a mechanism for maintaining each oijcyte in its respective temporal developmental sequence. Such a hiatus occurs when female cockroaches are starved; juvenile hormone secretion is inhibited, yolk deposition is curtailed, and vitellogenic oiicytes are resorbed in P. arfWcana (BELL. 197 1; BELL and BOHM, 1975) or arrested in Blatta arierltalis (SAMS, 1975). During the period of starvation, if a rigid sequence of oiicyte development were the case, then each o6cyte would have to cease further development and “mark time” until feeding re-initiated secretion of juvenile hormone and ensuing vitellogenic cycles. Thus. the proposed ovariole “clock” must be modulated by some extra-ovarian factor(s) which are at present not known. The “clock” and its modulators must govern a vitellogenic cycle which normally is continuous but subject to periods of vitellogenic arrest.
REFERENCES ASPAREN K. VAN and ESCH 1. VAN (1956) The chemical composition of haemolymph in Prriplanr~a uttleric~~~~u with special reference to the mineral constituents. .4r(h. r~e,rrl. Zoo/. 11. 342-360. BELL W. J. (1969a) Continuous and rhythmic reproductive cycle observed in Periplarzeta americana. Biol. Bull.. Woods Hole 137. 239-249. BELL W. J. (1969b) Dual rble of juvenile hormone in the control of yolk formation in Periplaneta umrricanu. J. Ifwct Physiol. 15. 1279-I 290. BELL W. J. (1971) Starvation-induced oijcyte resorption and yolk salvage in Periplarteta americana. J. Insrct Physiol. 17. 1099~1111. BELL W. J. (1972a) Transplantation of ovaries into male Periplaneta affwricaffa: effects on vitellogenesis and vitellogenin secretion. J. Insecr Physiol. 18, 851~855. BELL W. J. (1972b) Yolk formation by transplanted cockroach oiicytes. J. exp. 2001. 181, 41-48. BELL W. J. and BARTH R. H. JR. (1971) Juvenile hormoneinitiation of yolk deposition in a cockroach. Nature. N.B.. Land. 230. 220-221. BELL W. J. and SAMS G. R. (1977) Juvenile hormone control of yolk deposition in the American cockroach in vitro. Gen. conlp. Endocr. In press. BELL W. J. and BOHM M. K. (1975) Oosorption in insects. Biol. Rec. SO. 373-396. BRO~KES V. J. (1969) The induction of yolk protein synthesis in the fat body of an insect, Leucophaea maderae, by an analogue of the juvenile hormone. Devel. Biol. 20, 459-47 1. ENGELMANN N. F. (1969) Female specific protein: biosynthesis controlled by corpus allatum in Leucophueu maderae. Science, Wash. 165, 407-409.
Vitellogenic
cycle in the American
ENGEL~NN F. (19’Q T/w f%)smiog~ of’ lusrrl Rqvotiw tion 44. Internal :;eries monographs in pure and applied biology. Pergamon Press, New York. MILLS R. R., GREEI~SLADE F. C., and COIXH E. F. (1966) Studies on vitellogenesis in the American cockroach. J. It~srct Physiol. 12. 761-179. PAN M. L.. Bt1.1. W. J.. and TI:I.FER W. H. (1969) Vitello-
cockroach
897
gemc blood protein synthesis by inset fat bady. Sci~wr,. M/C&T.165. 393-394. SAMS G. R. (1975) Vitellogenic arrest in the cockroach. Bkmn orirrttulis. J. If7.swt Pl~~siol. 21. 1103% I71 0. WYSS-H~BER M. and L~:SCHEK M. (1972) III ritro synthesis and release of proteins by fat body and ovarian tissue of LCUL~O~/IIIPU. J. I/~wct Ph \xiol. 18. 6X9- 7 IO.