Spermiogenesis in the amphilinidean cestode Amphilina foliacea (Rudolphi, 1819) was examined using transmission electron microscopy. The orthogonal development of the two flagella is followed by a flagellar rotation and their proximodistal fusion with the median cytoplasmic process. This process is accompanied by extension of both the mitochondrion and nucleus into the median cytoplasmic process. The two pairs of electron-dense attachment zones mark the lines where the proximodistal fusion of the median cytoplasmic process with the two flagella takes place. The intercentriolar body, previously undetermined in A. foliacea, is composed of three electron-dense and two electron-lucent plates. Also new for this species is the finding of electron-dense material in the apical region of the differentiation zone at the early stage of spermiogenesis, and the fact that two arching membranes appear at the base of the differentiation zone only when the two flagella rotate towards the median cytoplasmic process. The present data add more evidence for a close relationship between the Amphilinidea and the Eucestoda.
a1_There are few studies on the morphology and meiosis in the testicles of Heteroptera, but are extremely important, especially for the family Pentatomidae, because in some species in this family meiosis in the testicular lobes results in the production of non-fertile spermatozoa. With the aim of improving the level of understanding of this phenomenon the morphology of the testes and spermatogenesis in 10 species of Pentatomidae were recorded and compared. All of them have testes covered by a pigmented peritoneal sheath. In some species the internal membrane or just inside the peritoneal sheath is pigmented. The pigmentation of both membranes varied. The pigmentation of both was either yellow, or the internal membrane was yellowish and the external one reddish. When the membrane is pigmented, the colour is red or yellow. The number of lobes varied from 3 to 7, with intermediate numbers of 4 and 6. The size and diameter of the lobes are similar in all the species studied, except Proxys albopunculatus, in which the diameter of the third and fifth is smaller than that of the other lobes. The behaviour of the cells during spermatogenesis was the same in all lobes of most species, except in P. albopunctulatus, in which the harlequin lobe is absent and the cells in lobes 4 and 6 exhibited characteristics different from those of cells in lobes 1-3 and 5. Chlorocoris complanatus and Loxa deducta (both Pentatominae) have a harlequin lobe (lobe 5). The chromosome complements recorded were: 2n = 12 (10A + XY) in Dichelops melacanthus and Edessa collaris, 2n = 14 (12A + XY) in C. complanatus, Edessa meditabunda, Ladeaschistus sp., Loxa deducta, P. albopunctulatus, Piezodorus guildinii and Thyanta perditor and 2n = 16 (14A + XY) in Edessa affinis. Thus, this study extends the knowledge of characteristics, such as the pigmentation of the peritoneal sheath, number of testicular lobes, the occurrence of meiotic cells in some, a2_testicular lobes, and the chromosome complements of the family Pentatomidae., and Hederson Vinícius De Souza, Aline Sumitani Murakami, Juliana De Moura, Elisângela Cristiane De Almeida, Inaiá Fernandes Gallego Marques, Mary Massumi Itoyama.
Effects of early neonatal interventions on metabolic parameters later in life (s.c. late effects) were studied in rats using two models; namely, (a) the effects of premature weaning and (b) the effects of "dietary" manipulations during the suckling period (s.c. small vs. large litters), (a) Premature weaning of rats caused an earlier degeneration of spermiogenesis and elevated plasma cholesterol levels in adult animals when compared to levels found in animals weaned 12 days later (on day 30 after birth). In adult rats, radioiodine uptake in thyroid glands was lower in the group weaned prematurely. Premature weaning was followed by a decrease of corticosterone production in adrenal glands in adult animals; in female adult prematurely weaned rats, an elevated response of adrenal cortex to stressors was observed. Several other studies explored the "immediate" effects of early, premature weaning, (b) Early exposure to high fat diet evoked a hypercholesterolaemic response in adulthood following brief exposure to HF diet. Rats from litters reduced to 3 or 4 pups per mother on postnatal day 3 exhibited 2 days later plasma levels of cholesterol higher than in rats raised in large litters of 8 or 14. The difference between small and large litters was preserved for the whole lifespan of the animals. In adulthood, rats from small litters were fatter and had higher levels of plasma cholesterol and insulin. Other studies suggester that early dietary experience may regulate the pattern of drug metabolism in adult life. An inhibition of diurnal plasma corticosterone variation was found in rats overfed during the neonatal period and an increased stimulation of lipolysis by norepinephrine and lipogenesis by insulin was demonstrated in neonatally underfed rats. Interesting studies were reported in longitudinally studies in children: at the age of 9-12 year brest-fed children (for more than 6 months) had the highest cholesterol levels; on the other hand significantly increased levels of APO B, Apo Al, ATH index and Apo/B Apo A1 quotient (p<0.05) were found in the nonbreast-fed group (27 references).
Spermatozoa of the monogenean Heterocotyle capricornensis Chisholm et Whittington, 1996 are long and filiform, comprising an elongate nucelus, probably a single elongate mitochondrion and two incorporated axonemes, one of which is shifted with respect to the other. The shift results in a region at each end of the sperm where only one axoncmc is present, accompanied by the nucleus and mitochondrion at one end and the nucleus and/or mitochondrion at the other. By taking note of the direction of dyncin arms on the axonemal doublet microtubules, each axoneme is identified and followed from beginning to end. No basal bodies remain in mature sperm but the main nuclear end is interpreted as proximal/anterior based on the final stages of spermiogenesis. A group of four or five cortical microtubules from the spermatid zone of differentiation persists in mature sperm, but is not closely associated with a region of extracellular matrix, as it is in other monocotylids. The sperm structure is compared with that of other monocotylids and the phylogenetic implications are discussed. Aberrant sperms in one individual were folded and fused along much of their length.
Spermatological characters of the liver fluke Mediogonimus jourdanei Mas-Coma et Rocamora, 1978 were studied by means of transmission and scanning electron microscopy. Spermiogenesis begins with the formation of the differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. These two centrioles originate two free flagella that undergo a 90° rotation before fusing with the median cytoplasmic process. Both nuclear and mitochondrial migrations toward the median cytoplasmic process occur before the proximodistal fusion of flagella. Finally, the constriction of the ring of arched membranes gives rise to the young spermatozoon. The mature sperm of M. jourdanei measures about 260 µm and presents two axonemes of different lengths with the typical pattern of the Trepaxonemata, two bundles of parallel cortical microtubules, one mitochondrion, a nucleus and granules of glycogen. An analysis of all the microphalloidean species studied to date emphasised some differences in certain characters found in Maritrema linguilla Jägerskiöld, 1908 and Ganeo tigrinum Mehra et Negi, 1928 in comparison to those in the remaining microphalloideans. The presence and variability of such ultrastructural characters according to family, superfamily or order have led several authors to propose their use in the analysis of trematode relationships and phylogeny. Therefore, apart from producing new data on the family Prosthogonimidae, the present study also compares the spermatological organization of M. jourdanei with other available ultrastructural studies focusing on the Microphalloidea.
Spermiogenesis and the ultrastructural organisation of the spermatozoon of the trypanorhynch cestode Aporhynchus menezesi Noever, Caira, Kuchta et Desjardins, 2010 are described by means of transmission electron microscopy. Type I spermiogenesis of A. menezesi starts with the formation of a differentiation zone containing two centrioles separated by an intercentriolar body constituted by five electron-dense plates. Each centriole gives rise to a free flagellum, which grows at an angle of 90° in relation to a median cytoplasmic process. The nucleus and cortical microtubules elongate along the spermatid body. Later, both flagella rotate and fuse with the median cytoplasmic process. At the final stage of spermiogenesis, the young spermatozoon is detached from the residual cytoplasm by a narrowing of the ring of arched membranes. The mature spermatozoon is a long and filiform cell, tapered at both ends, lacking mitochondria. It is characterized by the presence of two axonemes of the 9+'1' trepaxonematan pattern, the absence of crested bodies, the presence of parallel cortical microtubules and nucleus. This pattern corresponds to the type I spermatozoon of the eucestodes. The anterior extremity of the spermatozoon is characterized by the presence of an arc-like row of up to seven parallel cortical microtubules that partially surrounds the first axoneme. These anterior cortical microtubules are thicker than the posterior microtubules and, consequently, the sperm cell of A. menezesi exhibits two types of cortical microtubules. Another interesting aspect is the presence of α-glycogen rosettes. This spermatological pattern is similar to that observed in the spathebothriidean and diphyllobothriidean cestodes.
Ultrastructural characters of spermiogenesis and mature spermatozoon of Triaenorhina rectangula (Fuhrmann, 1908) are examined by transmission electron microscopy. Spermiogenesis follows the Bâ and Marchand's Type III spermiogenesis of cestodes. The process begins with the formation of a differentiation zone containing two centrioles and a cytoplasmic protrusion. The centrioles are associated with vestigial striated roots. One of the centrioles develops a free flagellum externally to the cytoplasmic protrusion. After a slight rotation, the free flagellum fuses with the cytoplasmic protrusion. In the final stage of spermiogenesis, a single crested body appears in the anterior part of the differentiating spermatozoon. The anterior extremity of the mature spermatozoon is characterised by an apical cone and a single crested body. The axoneme is of the 9+''1'' trepaxonematan type. A periaxonemal sheath and electron-dense rods are described in some parts of the mature spermatozoon. The nucleus is electron-dense and spirally coiled around the axoneme. The cortical microtubules are spirally arranged at an angle of about 40° to the spermatozoon axis. The present results show that the ultrastructural characters of spermiogenesis and mature spermatozoon of T. rectangula resemble most closely those in taeniids and metadilepidids. The comparison of these results with the only previous spermiological description of a paruterinid species reveals differences relative to the occurrence of filamentous rods of electron-dense material versus intracytoplasmic walls in the mature spermatozoon that may reflect the polyphyletic character of the Paruterinidae.
Spermiogenesis in Phyllobothrium lactuca Beneden, 1850 begins with the formation of a differentiation zone bordered by cortical microtubules and containing a nucleus and two ccntrioles separated by an intercentriolar body and disposed one in the prolongation of the other. Later, formation of flagellar buds, striated roots and a median cytoplasmic extension takes place. Each centriole gives rise to a flagellimi that rotates and fuses with the median cytoplasmic extension. At this stage, arched membranes appear at the front of the differentiation zone. The nucleus elongates, becomes filiform and migrates between the striated roots into the spermatid. After the migration of the nucleus, the old spermatid separates from the residual cytoplasm by strangulation of the ring of arched membranes. Absence of striated roots, right at the beginning of spermiogenesis has never been described before in the Tctraphyllidea. Likewise, centrioles made up of doublets of microtubules and spermatids with two axonemes have never been reported before during spermiogenesis of a Phyllobothriidae. In this work we show, for the first time, the existence in cestodes of thick-walled microtubulcs surrounded by a layer of electron-dense material. In addition, we describe, for the first time, the existence of an accumulation of electron-dense granules around striated roots and an hour-glass-shaped constriction at the anterior extremity of a median cytoplasmic extension in a platyhelminth.