Temporal silencing of an androgenic gland-specific insulin-like gene affecting phenotypical gender differences and spermatogenesis

Androgenic glands (AGs) of the freshwater prawn Macrobrachium rosenbergii were subjected to endocrine manipulation, causing them to hypertrophy. Transcripts from these glands were used in the construction of an AG cDNA subtractive library. Screening of the library revealed an AG-specific gene, termed the M. rosenbergii insulin-like AG (Mr-IAG) gene. The cDNA of this gene was then cloned and fully sequenced. The cysteine backbone of the predicted mature Mr-IAG peptide (B and A chains) showed high similarity to that of other crustacean AG-specific insulin-like peptides. In vivo silencing of the gene, by injecting the prawns with Mr-IAG double-stranded RNA, temporarily prevented the regeneration of male secondary sexual characteristics, accompanied by a lag in molt and a reduction in growth parameters, which are typically higher in males of the species. In terms of reproductive parameters, silencing of Mr-IAG led to the arrest of testicular spermatogenesis and of spermatophore development in the terminal ampullae of the sperm duct, accompanied by hypertrophy and hyperplasia of the AGs. This study constitutes the first report of the silencing of a gene expressed specifically in the AG, which caused a transient adverse effect on male phenotypical gender differences and spermatogenesis.

Insulin and gender: an insulin-like gene expressed exclusively in the androgenic gland of the male crayfish

Members of the insulin family of hormones are generally not regarded as gender-specific, although there is sporadic evidence for the possible involvement of insulin pathways in sexual differentiation. In crustaceans, sexual differentiation is controlled by the androgenic gland (AG), an organ unique to males. To date, attempts to identify active AG factors in decapods through either classical purification methods or sequence similarity with isopod AG hormones have proven unsuccessful. In the present study, the first subtractive cDNA library from a decapod AG was constructed from the red-claw crayfish Cherax quadricarinatus. During library screening, an AG-specific gene, expressed exclusively in males even at early stages of maturation and termed Cq-IAG (C. quadricarinatus insulin-like AG factor), was discovered. In situ hybridization of Cq-IAG confirmed the exclusive localization of its expression to the AG. Following cloning and complete sequencing of the gene, its cDNA was found to contain 1445 nucleotides encoding a deduced translation product of 176 amino acids. The proposed protein sequence encompasses Cys residue and putative cleaved peptide patterns whose linear and 3D organization are similar to those of members of the insulin/insulin-like growth factor/relaxin family and their receptor recognition surface. The identification of Cq-IAG is the first report of a pro-insulin-like gene expressed in a decapod crustacean in a gender-specific manner. Its expression in a male-specific endocrine gland controlling sex differentiation supports the notion that insulin may have evolved in the context of regulating sexual differentiation.

A sexual shift induced by silencing of a single insulin-like gene in crayfish: ovarian upregulation and testicular degeneration

In sequential hermaphrodites, intersexuality occurs naturally, usually as a transition state during sexual re-differentiation processes. In crustaceans, male sexual differentiation is controlled by the male-specific androgenic gland (AG). An AG-specific insulin-like gene, previously identified in the red-claw crayfish Cherax quadricarinatus (designated Cq-IAG), was found in this study to be the prominent transcript in an AG cDNA subtractive library. In C. quadricarinatus, sexual plasticity is exhibited by intersex individuals in the form of an active male reproductive system and male secondary sex characters, along with a constantly arrested ovary. This intersexuality was exploited to follow changes caused by single gene silencing, accomplished via dsRNA injection. Cq-IAG silencing induced dramatic sex-related alterations, including male feature feminization, a reduction in sperm production, extensive testicular degeneration, expression of the vitellogenin gene, and accumulation of yolk proteins in the developing oocytes. Upon silencing of the gene, AG cells hypertrophied, possibly to compensate for low hormone levels, as reflected in the poor production of the insulin-like hormone (and revealed by immunohistochemistry). These results demonstrate both the functionality of Cq-IAG as an androgenic hormone-encoding gene and the dependence of male gonad viability on the Cq-IAG product. This study is the first to provide evidence that silencing an insulin-like gene in intersex C. quadricarinatus feminizes male-related phenotypes. These findings, moreover, contribute to the understanding of the regulation of sexual shifts, whether naturally occurring in sequential hermaphrodites or abnormally induced by endocrine disruptors found in the environment, and offer insight into an unusual gender-related link to the evolution of insulins.

The eyestalk-androgenic gland-testis endocrine axis in the crayfish Cherax quadricarinatus

In decapod crustaceans, a number of neurohormones regulating a variety of physiological processes, including reproduction, are to be found in the X-organ-sinus gland complex of the eyestalk. Bilateral eyestalk ablation was thus performed in mature males of the Australian red claw crayfish Cherax quadricarinatus with the aim of studying the role of eyestalk-borne hormones on spermatogenic activity in the testis and on the androgenic gland (AG). The latter gland controls the differentiation and functioning of male sexual characteristics in crustaceans. Eyestalk ablation caused hypertrophy of the AG, as indicated by an increase in gland weight (3.9 +/- 0.44 mg vs < 0.1mg in intact males) and by overexpression of AG polypeptides. In the testes of eyestalk-ablated males, empty spermatogenic lobules were common, while lobules containing primary spermatocytes were infrequent. These findings were reflected in decreased amounts of DNA in these testes and a consequent increase in the relative weights of the sperm ducts. Since it was found that eyestalk ablation affected both the AG and the reproductive system, in vitro experiments were conducted to study the direct effects of the sinus gland on the AG and testes and of the AG on the testes. Sinus gland extracts inhibited by 30% the incorporation of radiolabeled amino acids into AG polypeptides and almost totally inhibited the secretion of radiolabeled AG polypeptides into the culture medium. However, sinus gland extracts had no significant effects on testicular tissue. On the other hand, AG extracts affected the in vitro phosphorylation of a testicular polypeptide (of 28 kDa), in a time- and dose-dependent manner, suggesting a direct effect of AG-borne hormones on the testes. The above findings, together with the evidence for direct inhibition by the sinus gland on the AG, suggest an endocrine axis-like relationship between the sinus gland, the AG, and the male reproductive system in decapod crustaceans.

Cloning of an insulin-like androgenic gland factor (IAG) from the blue crab, Callinectes sapidus: implications for eyestalk regulation of IAG expression

In malacostracan crustaceans, sex differentiation is uniquely regulated by a hormone secreted by the male-specific androgenic gland (AG). An isopod AG hormone was the first to be structurally elucidated and was found to belong to the insulin superfamily of proteins. Recently, it has been found that the AGs of several decapod crustaceans express insulin-like androgenic gland factors (IAGs), whose function is believed to be similar to that of the isopod AG hormone. Here we report the isolation from the blue crab Callinectes sapidus of the full-length cDNA encoding a candidate insulin-like AG hormone, termed Cas-IAG. The predicted protein Cas-IAG was encoded as a precursor consisting of a signal peptide, the B chain, the C peptide, and the A chain in that order. While the AG was the main source of Cas-IAG expression, as found in other decapod species, the hepatopancreas of male Callinectes sapidus crabs displayed minor Cas-IAG expression. Eyestalk ablation confirmed the presence of a possible endocrine axis between the eyestalk ganglia and the AG, implying that Cas-IAG expression is negatively regulated by (a) substance(s) present in the eyestalk ganglia.

Intraoral distraction osteogenesis of the mandible in hemifacial microsomia

PURPOSE

Lengthening of the mandible by distraction osteogenesis is the preferred method for treatment of hemifacial microsomia in children. Use of an intraoral distraction technique and horizontal oblique ramus osteotomy in such patients is presented.

PATIENTS AND METHODS

Mandibular ramus lengthening was performed in 11 patients aged 6 to 12 years with hemifacial microsomia. During the age of mixed dentition in hemifacial microsomia patients with a hypoplastic mandible, the unerupted molars buds are located high in the retromolar region and are in danger of being damaged by the osteotomy. Therefore, an intraoral approach exposing the mandibular ramus and angle was performed, and a horizontal oblique ramus osteotomy was made, preserving the inferior alveolar nerve. An intraoral device was placed along the ramus, and distraction was started on the third postoperative day at the rate of 1 mm/d and continued for 2 to 3 weeks or as long as necessary. The device was maintained for retention an additional 6 weeks and was then removed.

RESULTS

Clinically, the face became more symmetric. The postdistraction posteroanterior cephalometric radiographs demonstrated elongation of the affected ramus and improvement in facial symmetry.

CONCLUSIONS

The advantages of this method are that it allows device placement along the ramus, permitting the ramus elongation necessary in treatment of hemifacial microsomia, that it prevents damage to the tooth buds which, during the age of mixed dentition, are in a higher position in the retromolar area, and that it prevents injury of the inferior alveolar nerve.

Identification and Characterization of an Insulin-Like Receptor Involved in Crustacean Reproduction

Sexual differentiation and maintenance of masculinity in crustaceans has been suggested as being regulated by a single androgenic gland (AG) insulin-like peptide (IAG). However, downstream elements involved in the signaling cascade remain unknown. Here we identified and characterized a gene encoding an insulin-like receptor in the prawn Macrobrachium rosenbergii (Mr-IR), the first such gene detected in a decapod crustacean. In mining for IRs and other insulin signaling-related genes, we constructed a comprehensive M. rosenbergii transcriptomic library from multiple sources. In parallel we sequenced the complete Mr-IR cDNA, confirmed in the wide transcriptomic library. Mr-IR expression was detected in most tissues in both males and females, including the AG and gonads. To study Mr-IR function, we performed long-term RNA interference (RNAi) silencing in young male prawns. Although having no effect on growth, Mr-IR silencing advanced the appearance of a male-specific secondary trait. The most noted effects of Mr-IR silencing were hypertrophy of the AG and the associated increased production of Mr-IAG, with an unusual abundance of immature sperm cells being seen in the distal sperm duct. A ligand blot assay using de novo recombinant Mr-IAG confirmed the existence of a ligand-receptor interaction. Whereas these results suggest a role for Mr-IR in the regulation of the AG, we did not see any sexual shift after silencing of Mr-IR, as occurred when the ligand-encoding Mr-IAG gene was silenced. This suggests that sexual differentiation in crustaceans involve more than a single Mr-IAG receptor, emphasizing the complexity of sexual differentiation and maintenance.

Stimulation of molt by RNA interference of the molt-inhibiting hormone in the crayfish Cherax quadricarinatus

In crustaceans, molting is known to be under the control of neuropeptide hormones synthesized and secreted from the eyestalk ganglia. While the role of molt-inhibiting hormone (MIH) in regulating molting has been described in several species using classical methods, an in vivo specific MIH targeted manipulation has not been described yet. In the present study, an MIH cDNA was isolated and sequenced from the eyestalk ganglia of the Australian freshwater red claw crayfish Cherax quadricarinatus (Cq) by 5' and 3' RACE. We analyzed the putative Cq-MIH based on sequence homology, a three dimensional structure model and transcript's tissue specificity. We further examined the involvement of Cq-MIH in the control of molt in the crayfish through RNAi by in vivo injections of Cq-MIH double-stranded RNA, which resulted in, similarly to eyestalk ablation, acceleration of molt cycles. This acceleration was reflected by a significant reduction (up to 32%) in molt interval and an increased rate in molt mineralization index (MMI), which correlated with the induction of ecdysteroid hormones compared to control. Altogether, this study provides a proof of function for the involvement of the Cq-MIH gene in molt regulation in the crayfish.

Radiological features of glandular odontogenic cyst

OBJECTIVES

To present five new cases of glandular odontogenic cyst (GOC) and to review the radiological features at presentation as reported in the English literature.

METHODS

From 1993 to 2002, five patients in our department were diagnosed with GOC based on histopathological findings and supported by radiography and CT. The radiographic features of the new GOC cases were analysed in addition to 51 literature cases.

RESULTS

There were 31 male and 25 female patients, aged 14-90 years (mean 50 years). The mandible was involved in 80% and the maxilla in 20%; most of the lesions were located in the anterior jaw. Radiographically, 52% of the lesions were unilocular and 48% were multilocular; 94.5% showed well defined borders, which were sclerotic in 7.7% and scalloped in 13%. Information on cortical plate integrity was available in only 24 cases: 50% showed perforation, 8.3% erosion of the cortical plates and 8.3% thinning of the cortical plates. Root resorption was reported in 22% of patients and tooth displacement in 24.4%.

CONCLUSIONS

Data collected indicate that GOC has potentially aggressive behaviour, with expansion and perforation in a significant number of cases. We recommend the use of multiple plane radiographs, with CT reserved for large lesions, especially those that are multilocular or involve extragnathic structures.

Expression of an Androgenic Gland-Specific Insulin-Like Peptide during the Course of Prawn Sexual and Morphotypic Differentiation

The crustacean male-specific androgenic gland (AG) regulates sexual differentiation. In the prawn Macrobrachium rosenbergii, silencing an AG-specific insulin-like encoding transcript (Mr-IAG) inhibited the development of male sexual characters, suggesting that Mr-IAG is a key androgenic hormone. We used recombinant pro-Mr-IAG peptide to generate antibodies that recognized the peptide in AG cells and extracts, as verified by mass spectrometry. We revealed the temporal expression pattern of Mr-IAG and studied its relevance to the timetable of sex differentiation processes in juveniles and after puberty. Mr-IAG was expressed from as early as 20 days after metamorphosis, prior to the appearance of external male sexual characters. Mr-IAG expression was lower in the less reproductively active orange-clawed males than in both the dominant blue-clawed males and the actively sneak mating small males. These results suggest a role for Mr-IAG both in the timing of male sexual differentiation and in regulating reproductive strategies.

Increased endothelial cell expression of alpha3beta1 integrin in cardiac valvulopathy in the primary (Hughes) and secondary antiphospholipid syndrome

The objective of this work was to determine markers of endothelial cell activation in valves from patients with antiphospholipid syndrome (APS) and heart valve involvement, in order to establish a role for endothelial cells in the pathogenesis of the valvular disease. Sixteen valves from ten patients with APS, obtained from autopsies or removed during valve replacement, were studied. Two groups of valves were used as controls. One group included seven normal valves from patients who died from non-cardiac diseases. The other group of valves were obtained from patients with bacterial endocarditis during autopsies or valve replacement operations. Immunoperoxidase and immunofluorescence stainings with antibodies to human immunoglobulins, endothelial cells, alpha3beta1 integrin, collagen IV, laminin and fibronectin were employed. Three histopathological patterns were apparent: normal valves, valves with verrucous endocarditis and valves with fibrocalcific changes. In all the valves with verrucous endocarditis the following findings were observed: (1) increased expression of the alpha3beta1 integrin on the endothelial cells, (2) increased amount of collagen IV, laminin and fibronectin, (3) proliferation of blood vessels and (4) linear subendothelial deposition of immunoglobulins and complement. The valves with fibrocalcific changes were deformed and showed a thick layer of collagen IV, laminin and fibronectin, yet in two valves the indothelial cells showed an expression of the alpha3beta1 integrin. The control valves did not express the integrin and had only a thin subendothelial band of collagen IV. In valves from patients with APS, 1 markers of endothelial cell activation are upregulated while the inflammatory exudate is scant. There is also a prominent deposition of immunoglobulins in the valves from patients with APS, suggesting a possible association between the deposition of the antibodies and the activation of the endothelial cells in APS.

A crayfish insulin-like-binding protein: another piece in the androgenic gland insulin-like hormone puzzle is revealed

Across the animal kingdom, the involvement of insulin-like peptide (ILP) signaling in sex-related differentiation processes is attracting increasing attention. Recently, a gender-specific ILP was identified as the androgenic sex hormone in Crustacea. However, moieties modulating the actions of this androgenic insulin-like growth factor were yet to be revealed. Through molecular screening of an androgenic gland (AG) cDNA library prepared from the crayfish Cherax quadricarinatus, we have identified a novel insulin-like growth factor-binding protein (IGFBP) termed Cq-IGFBP. Based on bioinformatics analyses, the deduced Cq-IGFBP was shown to share high sequence homology with IGFBP family members from both invertebrates and vertebrates. The protein also includes a sequence determinant proven crucial for ligand binding, which according to three-dimensional modeling is assigned to the exposed outer surface of the protein. Recombinant Cq-IGFBP (rCq-IGFBP) protein was produced and, using a "pulldown" methodology, was shown to specifically interact with the insulin-like AG hormone of the crayfish (Cq-IAG). Particularly, using both mass spectral analysis and an immunological tool, rCq-IGFBP was shown to bind the Cq-IAG prohormone. Furthermore, a peptide corresponding to residues 23-38 of the Cq-IAG A-chain was found sufficient for in vitro recognition by rCq-IGFBP. Cq-IGFBP is the first IGFBP family member shown to specifically interact with a gender-specific ILP. Unlike their ILP ligands, IGFBPs are highly conserved across evolution, from ancient arthropods, like crustaceans, to humans. Such conservation places ILP signaling at the center of sex-related phenomena in early animal development.

Post-embryonic transcriptomes of the prawn Macrobrachium rosenbergii: multigenic succession through metamorphosis

Like many metazoans, the freshwater prawn Macrobrachium rosenbergii begins its post-embryonic life with a set of morphologically distinct planktonic larval stages, followed by a benthic post-larval stage during which the maturing organism differs from the larvae both ecologically and physiologically. Understanding of the molecular basis underlying morphogenesis in crustaceans is limited to the observation that methyl farnesoate, the non-epoxidated form of the insect juvenile hormone, acts as the active crustacean juvenoid. Molt steroids were also linked to morphogenesis and several other molecular pathways, such as Hedgehog and Wnt, are known to underlie morphogenesis in all metazoans examined and, as such, are thought to do the same in crustaceans. Using next generation sequencing, we deep-sequenced the transcriptomes of several larval and post-larval stages. De novo assembly, followed by bioinformatics analysis, revealed that many novel transcripts are over-expressed in either larvae- or post-larvae-stage prawn, shedding light on the molecular basis underlying M. rosenbergii metamorphosis. Fast larval molting rates and periodic morphological changes were reflected in over-expression of transcripts annotated to the cell cycle, DNA replication and morphogenic pathways (i.e., Hedgehog and Wnt). Further characterization of transcripts assigned to morphogenic pathways by real-time RT-PCR reconfirmed their over-expression in larvae, albeit with a more complex expression pattern when examined in the individual developmental stages. The expression level of an orthologue of cytochrome P450, 15A1, known to epoxidize methyl farnesoate in insects, was increased in the late larval and early post-larval stages, in accordance with the role of methyl farnesoate in crustacean metamorphosis. This study exemplifies the applicability of a high-throughput sequencing approach for studying complex traits, including metamorphosis, providing new insight into this unexplored area of crustacean research.

Intersexuality and behavior in crayfish: the de-masculinization effects of androgenic gland ablation

In crustaceans, male differentiation and primary and secondary characteristics are regulated by the androgenic gland (AG). In gonochoristic crustaceans, the AG is also linked to intersexuality. Whereas the co-occurrence of various male and female characteristics has been demonstrated in intersex crustaceans, little is known regarding sexually dimorphic behavior patterns in such individuals. In the present study, we used an intersex crayfish model to investigate--for the first time in crustaceans--the agonistic and mating behavior of intersex individuals, and to explore the effects of AG ablation on behavior, morphology and physiology. As was the case for their morphological and physiological reproductive traits, intersex individuals--despite being genotypically females--generally resembled males in terms of behavior: they engaged in fighting with males and copulated with receptive females. However, fighting durations of intersex animals were intermediate between those of males and females, and the durations of the copulations were remarkably short. Adult intersex individuals that had been AG ablated at the juvenile stage were unlikely to engage in fighting with males (similar behavior to females) and did not exhibit any mating behavior with receptive females. AG ablation resulted in feminine morphological and physiological shifts in the treated intersex individuals and enabled vitellogenin gene transcription and the onset of secondary vitellogenesis. It thus appears that an as-yet-unknown AG-secreted factor(s) regulating maleness also seems to regulate the organization of male behavior in crustaceans.

Male-like behavioral patterns and physiological alterations induced by androgenic gland implantation in female crayfish

The androgenic gland (AG) has been shown to regulate male sexual differentiation and secondary male characteristics in Crustacea. This study presents for the first time in crustaceans evidence for masculinization effects of the AG on reproductive behavior, in addition to morpho-anatomical and physiological effects. AG implantation into immature female red claw crayfish Cherax quadricarinatus inhibited secondary vitellogenesis and development of the ovaries, as well as morphological traits that facilitate maternal egg brooding; it also caused the appearance of secondary male characteristics. However, primary male characteristics and a masculine reproductive system were not developed. In pair encounters, aggression was substantially lower in interactions between AG-implanted and intact females than in interactions within AG-implanted or intact pairs. Moreover, elements of mating behavior, i.e. male courtship displays and false copulations, were exhibited by AG-implanted females in several encounters with intact females. In addition to known morpho-anatomical and physiological effects of the AG in crustaceans, the present study suggests that the AG has novel effects on the neural network that generates social behavior.

A Putative Insulin-like Androgenic Gland Hormone Receptor Gene Specifically Expressed in Male Chinese Shrimp

The insulin-like androgenic gland hormone (IAG) is the key regulator in crustacean male sexual differentiation. As a secreted peptide hormone, IAG might perform its biological function through interacting with the membrane receptor. However, the receptor of IAG remains unclear. In the current study, a putative IAG receptor gene (FcIAGR) was identified in Fenneropenaeus chinensis. The deduced amino acid sequence of FcIAGR contained several conserved domains of insulin-like receptor proteins, including two L domains (L1 and L2), a cysteine-rich domain, three fibronectin III domains, a transmembrane domain, and an intracellular tyrosine kinase domain. Tissue distribution and in situ hybridization analysis showed that FcIAGR was predominantly expressed in the androgenic gland and testis in male F. chinensis. Protein colocalization analysis in HEK293 cells showed that FcIAGR could colocalize with both FcIAG1 and FcIAG2, respectively. Yeast two-hybrid assay further confirmed the interactions between FcIAGR and FcIAGs. After a long-term silencing of FcIAGR with double-stranded RNA, most of the germ cells in the testis were arrested at the secondary spermatocytes, whereas those in the control developed into sperm cells. The data indicated that FcIAGR was the receptor of FcIAGs in F. chinensis. The current study provides insight into the mechanism that the insulin-like signaling pathway regulates the male sexual differentiation in Decapoda crustaceans.

A Single Injection of Hypertrophied Androgenic Gland Cells Produces All-Female Aquaculture

Monosex culture, common in animal husbandry, enables gender-specific management. Here, production of all-female prawns (Macrobrachium rosenbergii) was achieved by a novel biotechnology comprising three steps: (a) A single injection of suspended hypertrophied androgenic gland cells caused fully functional sex reversal of females into "neo-males" bearing the WZ genotype; (b) crossing neo-males with normal females (WZ) yielded genomically validated WW females; and (c) WW females crossed with normal males (ZZ) yielded all-female progeny. This is the first sustainable biotechnology for large-scale all-female crustacean aquaculture. The approach is particularly suited to species in which females are superior to males and offers seedstock protection, thereby ensuring a quality seed supply. Our technology will thus revolutionize not only the structure of the crustacean aquaculture industry but can also be applied to other sectors. Finally, the production of viable and reproducible females lacking the Z chromosome questions its role, with respect to sexuality.

Identification of receptor-interacting regions of vitellogenin within evolutionarily conserved β-sheet structures by using a peptide array

Vitellogenesis, a key process in oviparous animals, is characterized by enhanced synthesis of the lipoprotein vitellogenin, which serves as the major yolk-protein precursor. In most oviparous animals, and specifically in crustaceans, vitellogenin is mainly synthesized in the hepatopancreas, secreted to the hemolymph, and taken up into the ovary by receptor-mediated endocytosis. In the present study, localization of the vitellogenin receptor and its interaction with vitellogenin were investigated in the freshwater prawn Macrobrachium rosenbergii. The receptor was immuno-histochemically localized to the cell periphery and around yolk vesicles. A receptor blot assay revealed that the vitellogenin receptor interacts with most known vitellogenin subunits, the most prominent being the 79 kDa subunit. The receptor was, moreover, able to interact with trypsin-digested vitellogenin peptides. By combining a novel peptide-array approach with tandem mass spectrometry, eleven vitellogenin-derived peptides that interacted with the receptor were identified. A 3D model of vitellogenin indicated that four of the identified peptides are N-terminally localized. One of the peptides is homologous to the receptor-recognized site of vertebrate vitellogenin, and assumes a conserved β-sheet structure. These findings suggest that this specific β-sheet region in the vitellogenin N-terminal lipoprotein domain is the receptor-interacting site, with the rest of the protein serving to enhance affinity for the receptor. The conservation of the receptor recognition site in invertebrate and vertebrate vitellogenin might have vast implications for oviparous species reproduction, development, immunity, and pest management.

Screening for Dmrt genes from embryo to mature Macrobrachium rosenbergii prawns

The doublesex and mab-3 related transcription factor (Dmrt) gene family is known to be related to the sexual regulators doublesex of arthropods and mab-3 of annelids and to hold highly conserved functions in sexual determination and differentiation across phyla. Here, we report a study of the Dmrt gene family in the freshwater prawn Macrobrachium rosenbergii, a crustacean whose sexual differentiation has been widely researched. A wide transcriptomic screen, from the embryo to the adult M. rosenbergii, identified five novel Dmrt genes (MroDmrts) and confirmed two known MroDmrts. The seven MroDmrts encode proteins of 275-855 amino acids; each protein contained at least one conserved DNA-binding DM domain, which is typical of Dmrt proteins, and five proteins contained 1-4 transactivation domains (TADs). Importantly, in the embryonic, larval and post-larval stages, MroDmrt genes exhibited time-dependent expression patterns rather than sex-specific expression. In-silico screening of the expression of the MroDmrt genes in adult males revealed the enrichment of MroiDmrt1b and MroiDmrt1c in the androgenic gland (AG) as compared to the eyestalks. In vivo silencing of the androgenic gland insulin-like (IAG) encoding gene significantly decreased the expression of the above two Dmrt genes, while not affecting the expression of control genes, thereby suggesting the possible role of these two genes in the IAG-switch and in sex-differentiation processes.

Uremic optic neuropathy. A uremic manifestation mandating dialysis

A 41-year-old male patient in end-stage renal failure presented on two occasions, over an 18-month period, with painless unilateral visual deterioration and optic disc edema. Clinical findings were compatible with a diagnosis of uremic optic neuropathy. On his initial presentation, the patient refused the onset of dialysis, resulting in a permanent visual deficit of the left eye. On his subsequent admission with a similar clinical picture, this time of the right eye, dialysis combined with corticosteroid therapy was promptly instituted. This led to a rapid improvement of the visual acuity and visual field defects of the right eye concomitant with subsidence of the edema of the optic nerve head.