Mandibular organ: it's relation to body weight, sex, molt and reproduction in the crab, Oziotelphusa senex senex Fabricius (1791)

Nagaraju, Ganji Purnachandra; Reddy, P. Ramachandra; Reddy, P. Sreenivasula

doi:10.1016/s0044-8486(03)00519-2

Cited by 36 publications

(31 citation statements)

References 35 publications

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Section: T-test) (B)mentioning

confidence: 95%

“…The difference in MF levels between green-and red-phase animals disappears 5 days after ESA. This probably reflects the hypertrophy of the MO, which is known to occur after ESA (Borst et al, 1994;Nagaraju et al, 2004).Although a hyposalinity challenge had no significant effect on the MF levels of green-or red-phase animals after ESA, there was a modest effect in SW at 18°C. This suggests that the eyestalk is the major regulator of MF levels in response to salinity.…”

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confidence: 92%

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Methyl farnesoate couples environmental changes to testicular development in the crabCarcinus maenas

Nagaraju

Borst

2008

Journal of Experimental Biology

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SUMMARYCarcinus maenas males have two major color phases. Green-phase males molt frequently and tend to live in brackish estuaries during the summer. After becoming red-phase males, they molt infrequently, have higher mating success, and live in cooler, deeper water. We found profound differences between these two phases in the way salinity and temperature affect hemolymph levels of methyl farnesoate (MF), a hormone that affects crustacean reproduction. Few green-phase males (<10%) had detectable MF in 33 ppt seawater (SW) at 11 or 18°C. By contrast, about 30% of the red-phase males had detectable MF at either temperature. After transfer to 5 ppt SW, none of the green-phase males had detectable MF at 11°C whereas 100% of green-phase males did at 18°C. By contrast, 100% of the red-phase males had detectable MF in 5 ppt SW at either temperature. At 11°C, green-phase males had detectable MF after eyestalk ablation (ESA), showing that they can produce MF. There was no additional increase in MF levels when ESA animals of either color phase were transferred to 5 ppt SW, suggesting that the eyestalk is the primary regulator of the MF response to low salinity. MF levels of green-phase males were increased by injecting MF, by ESA, or by exposure to 5 ppt SW at 18°C. The testicular index of these treated animals nearly doubled after two weeks. Our results strongly suggest that environmental conditions such as temperature and salinity, affect testicular development in this crab by changing its MF levels.Key words: methyl farnesoate, testis, crustacean, salinity, reproduction, temperature. THE JOURNAL OF EXPERIMENTAL BIOLOGY 2774In the present study, we show that red-phase crabs are more likely to have detectable MF in their hemolymph than green-phase crabs. In addition, the testicular index (TI) of red-phase animals is higher than that in green-phase animals. Furthermore, our results indicate that environmental factors differentially affect MF levels in the two color phases. These results are consistent with the hypothesis that MF stimulates testicular development. To test this hypothesis, we show that environmental factors that increase MF levels also stimulate testicular development. The MF levels in these two color phases appear to be responsible, in part, for the different reproductive activities of these males. MATERIALS AND METHODS AnimalsCrabs [Carcinus maenas (Linnaeus 1758)] were generously provided by Dan Landers (Millstone Environmental Lab; Waterford, CT, USA). Most of the males used in this study were 50±5 g (carapace width, CW 5.2±0.6 cm) and were collected during the spring and early summer. Green-phase and red-phase animals were identified by the color of their ventral surface (Reid et al., 1997). None of the experimental animals was missing appendages. At the end of some experiments, the testes were removed and weighed, and the TI (% total body mass) was calculated. Crabs were kept in large tanks containing artificial SW (Instant Ocean, Spectrum Brands; Atlanta, GA, USA) at normal salinity (33 ppt) at 11 o...

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Section: T-test) (B)mentioning

confidence: 95%

mentioning

confidence: 92%

Methyl farnesoate couples environmental changes to testicular development in the crabCarcinus maenas

Nagaraju

Borst

2008

Journal of Experimental Biology

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“…These results are important because ESA also removes another inhibitory peptide, GIH/VIH (Que-Tae et al, 1999). Administration of MF stimulated ovarian maturation and testicular development in several crustacean species (Nagaraju, 2007;Nagaraju and Borst, 2008;Nagaraju et al, 2004;Nagaraju et al, 2003). In vitro studies showed that MF stimulated oocyte size and Vg messenger in HP and the ovary (Otsu, 1963).…”

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confidence: 98%

“…High MF levels were also correlated with mating behavior; males with higher MF levels actively courted and coupled with females, while males with lower MF levels did not show this behavior (Sagi et al, 1994). In addition, in the crab O. senex senex, the green crab, C. maenus, and the prawn M. malcholumsonii, injection of MF caused an increase in the testicular index (Kalavathy et al, 1999;Nagaraju and Borst, 2008;Nagaraju et al, 2004). These results suggested that MF stimulates the testes either directly or indirectly by stimulating (GSF or AGH) or inhibiting GIH secretions.…”

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confidence: 98%

Reproductive regulators in decapod crustaceans: an overview

Nagaraju

2011

Journal of Experimental Biology

267

177

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SummaryControl of reproductive development in crustaceans requires neuropeptides, ecdysone and methyl farnesoate (MF). A major source of neuropeptides is the X-organ-sinus gland (XO-SG) complex located in the eyestalk ganglia of crustaceans. The other regulatory factors (either peptides or neuromodulators) are produced in the brain and thoracic ganglia (TG). Two other regulatory non-peptide compounds, the steroid ecdysone and the sesquiterpene MF, are produced by the Y-organs and the mandibular organs, respectively. In the current review, I have tried to recapitulate recent studies on the role of gonadal regulatory factors in regulating crustacean reproduction.Key words: crustaceans, reproduction, gonads, X-organ-sinus gland, peptides. THE JOURNAL OF EXPERIMENTAL BIOLOGY4 crustaceans, the testis contains 10-15 lobes each composed of many seminiferous tubules, whose shape changes according to the stage of spermatogenesis. Spermatogenesis starts in the undifferentiated seminiferous tubules (proacini) at the top of each lobe. Meiotic activity occurs in the acini that develop proacini somewhat proximally from the top of each lobe. In this stage, the lobules contain mostly primary spermatocytes. Differentiation of secondary spermatocytes and spermatids takes place in the seminiferous tubules, which lie in the center of each lobe. All these seminiferous tubules are filled with spermatocytes and spermatids surrounded by a layer of otheocytes of mesodermal origin. The hormonal control of spermatogenesis is not completely understood in crustaceans. There is information on MF as a reproductive hormone in males. The female reproductive systemThe reproductive system of female crustaceans consists of the paired ovaries, oviducts, gonophores and an external sperm reception area. The ovarian lobes are connected by a central bridge of ovarian tissue (Fig.1D). The ovarian lobes are symmetrically arranged and lie in the cephalothorax on the top of the stomach and hepatopancreas (HP). An oviduct arises laterally from each ovary at a point just beside the position of the heart. It extends ventrally and opens through a gonophore in the abdomen. In sexually receptive females, each pore is equipped with a large tuft of long setae, which apparently serve as a tube for the passage of ova. In the fully mature state, the shapes of ovarian limbs can be distinguished only with difficulty as the ovary fills the thoracic region of the body cavity completely.In the majority of female Malacostraca, oogonial proliferation and ovarian differentiation take place when the ovary is translucent to opaque white (previtellogenic ovary). During vitellogenesis the color of the ovary changes from pale yellow (vitellogenic stage I) to orange (vitellogenic stage II) and it then becomes brown (vitellogenic stage III) to dark brown prior to spawning. Maturation of the ovary also includes an increase in the size of the ovary as the oocytes proliferate and increase in diameter, due to yolk deposition. Role of neuropeptides in reproductionThe hormonal control o...

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“…No mortality was observed in MF injected group and observed all of them are in late vitellogenic stage (III) with significant increase (p<0.0001) in ovarian index (508.84%), oocyte diameter (1004.16%) and ovarian vitellogenin levels (137.57%) ( Table 1). MF is known to be involved in the regulation of reproduction in various crustaceans [18,25,28,[33][34][35][36][37]. Similar to ovarian index, oocyte diameter and ovarian vitellogenin levels, observed significant increase (p<0.0001) in the ovarian total lipid and protein in both ESX and MF injected prawns ( In MF injected animals, the lipid and protein levels were significantly increased when compared with control and eyestalk ablated animals.…”

Section: Resultsmentioning

confidence: 87%

Methyl Farnesoate Induced Ovarian Maturation in Freshwater Prawn, Macrobrachium rosenbergii

Hemalatha¹,

Parameswari²,

Kishori³

et al. 2017

J Oceanogr Mar Res

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The present study focused to elucidate the effect of methyl farnesoate (MF) on ovarian development and maturation in the freshwater giant prawn, Macrobrachium rosenbergii. Control, eyestalk ablated (ESX) and MF injected prawns were maintained during the experimentation and observed significant (p<0.001) increase in the mean ovarian index, oocyte diameter and ovarian vitellogenin levels in both eyestalk ablated and methyl farnesoate administered prawns when compared with controls. All the MF injected animals are in vitellogenic stage III, whereas ESX animals were showed all the reproductive stages at 30th day of experiment. The levels of protein and lipid in the ovary were also measured. The total protein and lipid content levels were also significantly increased in eyestalk ablated (145.07% and 72.05% respectively) and MF injected animals (315.21% and 118.39% respectively) than the controls. The outcome of the present study clearly suggests that MF stimulates the reproduction in female prawns than the conventional ESX method.

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Mandibular organ: it's relation to body weight, sex, molt and reproduction in the crab, Oziotelphusa senex senex Fabricius (1791)

Cited by 36 publications

References 35 publications

Methyl farnesoate couples environmental changes to testicular development in the crabCarcinus maenas

Methyl farnesoate couples environmental changes to testicular development in the crabCarcinus maenas

Reproductive regulators in decapod crustaceans: an overview

Methyl Farnesoate Induced Ovarian Maturation in Freshwater Prawn, Macrobrachium rosenbergii

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