Oviducal glands throughout the gonad development stages: a case study ofOctopus mimus(Cephalopoda) (original) (raw)
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Marine and Freshwater Research, 2004
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Gonad development during the early life of Octopus maya (Mollusca: Cephalopoda)
Biological Bulletin, 2009
Gonad development during the early life of Octopus maya is described in terms of histological, morphometric, oocytes growth, and somatic-oocyte relationship data obtained from octopus cultured at the UMDI-UNAM, in Sisal, Yucatan, Mexico. This study is the first publication on gonad development during the early life of Octopus maya. A total of 83 O. maya specimens were used; their sizes ranged from 6.5 to 76 mm of total length (TL), 4 to 28 mm of dorsal mantle length (DML), 2.5 to 20 mm of ventral mantle length (VML), and 0.0180 to 7.2940 g of fixed body weight (fBW). Animals were weighed and measured only after preservation. A loss of 10% of living weight was estimated for juvenile octopuses after formalin preservation. The relation of length to weight (VML, DML, TL/fBW) pooled for both sexes had a strong positive correlation (r), as shown by a potential power function that was quite close to 1. Compound images were produced from numerous microscopic fields. The histological examination revealed that, 4 months after hatching, male octopus (24.5 mm DML and 7.2940 g fBW) were in gonad stages 2 (maturing) to 3 (mature), with spermatogonia and spermatocytes in the tubule wall and abundant spermatids and spermatozoa in the central lumen of the seminiferous tubules, suggesting the occurrence of different phases of gonad development at different maturity stages. In contrast, females (22.5 mm DML and 4.8210 g fBW) at the same time since hatching were immature (stage 1), with many oogonia, few oocytes, and germinal epithelium. This suggests that males reach maturity earlier than females, indicating a probable onset of maturity for males at around 4 months of culture or 8 g of wet body weight. Our results indicate the possibility that the size-at-weight can be recognized early with a degree of certainty that allows the sexes to be separated for culture purposes; but more detailed studies on reproduction in relation to endocrinology and nutrition are needed.
4th Workshop on Gonadal Histology of Fishes
2010
Proceedings of the 4th Workshop on today to classify a female into the right maturity stage or phase (sub-stage). Here the males are ignored, as often done, but there does also exist reliable histological classification schemes for this gender, although demanding a higher level of expertise. Oocyte recruitment Studies on oocyte recruitment are very limited in the fish literature, primarily because of the high complexity in enumerating these small cells. The most natural route to take is by using sophisticated stereology (see Hagstrøm Bucholtz et al. this WS), but the procedure is extremely laborious and is complicated by shrinkage/distortion problems along the so-called z-axis. Thus, we advocate also the use of advanced packing density formulae (Kurita and Kjesbu 2009) in combination with Delesse principle (see Korta et al. this WS). The concept of natural down-regulation (Kurita et al. 2003) has opened up a completely new understanding of oocyte number regulation and thereby quantification and standardization. However, to understand the underlying processes, histology is clearly required to address atresia formation and fate. Atresia Studies on atresia have been ongoing for many years but only now one can say if it is being correctly quantified. The combination of image analyses (whole mount) using specific stains and validation by histology look very promising for further method development (Witthames et al. 2009).
Hydrobiologia, 2014
We contrasted histological characteristics with a macroscopic maturity scale in Octopus vulgaris. Seven histological stages of maturation were identified, and a stereological method was used to develop a new histological maturity index (HMI). This index was related to the gonadosomatic index giving the possibility to estimate the histological stage of individual octopus without sampling the gonads. However, the existing macroscopic maturity scale produced some degree of overlap along the range of HMI, suggesting that this macroscale at this moment might be just good enough to separate immature from fully mature individuals. A histological maturity criterion based on the presence of a larger proportion of folding oocytes compared to earlier microstages resulted in a size at maturity of 1.5 kg. However, using two different macroscopic criteria, size at maturity was 1.3 and 2.3 kg. The estimate of size at maturity is therefore sensitive to the maturity criteria used. The maturation cycle of female O. vulgaris was seasonal, peaking in spring months and reaching a maximum of reproductive activity in April independently of the maturation criteria used. Oogenesis was reviewed and found to be an asynchronic process. Our results suggest that there is a need to examine all these issues in other cephalopod species.
Histological Analysis of the Reproductive System and Gonad Maturity of Octopus rubescens
International Journal of Morphology, 2013
This study described the reproductive system and gonadal development of Octopus rubescens from Bahía de Todos Santos, Baja California, Mexico. A total of 65 organisms, 35 males weighing 7.2 to 543.4 g and 30 females from 9.4 to 87.7 g where analyzed. The gonad development was defined through histological methods using Hematoxylin-eosin and Arteta-trichrome stains. We describe macroscopically the reproductive system of males and females, and characterized each of the anatomic components. Eight stages of maturity were recognized in females: 1. Immature, 2. Initial folliculogenesis, 3. Final folliculogenesis, 4. Previtelogenesis, 5. Early vitelogenesis, 6. Final vitelogenesis, 7. Maturing and 8. Spawn. In males five stages were identified: 1. Immature, 2. Maturing A, 3. Maturing B, 4. Mature type 1 and 5. Mature type 2. This work is the first histological description of the reproductive system of this species and the beginning for future research on its basic biology.
Journal of Fish Biology, 1989
The testicular gland (t.g.) is a glandular tissue situated adjacent to the testis of blenniid and several gobiid species. In the present study the t.g. of Blennius pavo Risso and Gobius niger L. were compared by histological and histochemical methods. In B. pavo the spermatozoa have to cross the t.g. to reach the vas deferens and thus they come into contact with the gland cells, whereas in G. niger the vas deferens is situated between the testis and the t.g. The fine structure and histochemistry of the t.g. cells reveal that in B. p a w the cells of the t.g. have exocrine as well as endocrine functions. The t.g. cells of B. pavo contain large amounts of lipids, form a secretion containing acid mucopolysaccharides, show positive reaction for acid phosphatase, and some cells stain for 3b-HSD and G6PD. The function of the t.g. of G. niger is exclusively endocrine. Characteristics of the gland cells of this species are well developed smooth ER and tubulovesicular or paracristalline mitochondria. The stainings for 3p-HSD. G6PD and UDPGD give strong positive results in the whole t.g., indicating the presence of steroids and steroid glucuronides.
Molluscan Research, 2015
Variations in progesterone (P4) and testosterone (T) levels in the gonad of Octopus maya from Sisal in Yucatan State, Mexico, were investigated by radioimmunoassays and in relation to four gonad maturation stages (GMS) and to the reproductive cycle, as represented by two maturity indices (microscopic ‘MiMI’ and macroscopic ‘MaMI’). According to the GMS and the maturity indices, the reproductive season of O. maya from Yucatan occurred from February to June. In females, P4 and T displayed the same pattern, with a tendency to increase at the same time, although on average, P4 had seven-fold higher concentrations than T. In contrast, P4 and T in male gonads displayed a different pattern, where T concentrations were relatively stable throughout all of the study months. In the female gonad P4 was lowest (close to 0 pg g–1) during both developing (GMS-I) and maturing (GMS-II) stages, and increased (189 ± 53 pg g–1) approaching the mature stage (GMS-III) to a maximum value of 611 pg g–1. Concentrations of T in the male gonad were lowest (106 ± 9 pg g–1) during the maturing stage (GMS-II) and increased up to the mature stage (GMS-III), reaching a maximum of 440 pg g–1. Pearson's correlation (r) between hormones and maturity indices showed strong relationships for females (around 0.4 and −0.7; p < 0.05), but there were negligible or weak relationships for males (0.2 and −0.1; p > 0.05). Hormone correlations in females were inverse with MaMI and direct with MiMI. Our major findings showed that gonadal P4 levels were elevated during GMS-III and GMS-IV (i.e. periods of vitellogenic oocytes), where the characteristic aspect is an ovary with very high oocyte diameters, with the primary follicle cells deeply infolded in the ooplasm for yolk synthesis. These results suggested a synchrony between P4 and the process of folliculogenesis, and in turn, vitellogenesis.
Their Presence and Function in Relation to Anatomical Region and Oestrous Cycle Stage
2006
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