The ultrastructure of the spermatheca of Mordellistena brevicauda (Coleoptera, Tenebrionoidea) and the associated bacterial cells.

The ultrastructural study on the female reproductive system of the beetle M. brevicauda (Mordellidae) confirmed the positive correlation between the length of the sperm and the size of the female seminal receptacle (Spermatheca). The spermatheca of the species is characterized by an apical bulb-like structure where the spermathecal duct forms numerous folds filled with sperm. At this level many bacterial cells are present intermingled with the duct folds. Some are organized in large structures, such as bacteriomes, while other are single bacteriocytes. The latter are often found near the basal lamina of duct epithelium. In addition, some bacteria are visible in the cytoplasm of the duct epithelial cells. Interestingly, bacterial cells have never been observed in the duct lumen. The possible function of the bacterial cells is discussed.

The sperm ultrastructure of Spermophagus kuesteri Schilsky, 1905 (Chrysomelidae, Bruchinae) and considerations on the relationships of Cucujiformia superfamilies.

The sperm ultrastructure of the bean-weevil Spermophagus kuesteri (Bruchinae) was studied to verify the congruence of the new position of the subfamily within Chrysomelidae. The results indicated a positive answer to the question supporting a close relationship between Chrysomelidae and Curculionidae, a finding confirmed also by molecular data. Moreover, the sperm morphology of Divales cinctus, a member of Melyridae (Cleroidea) allowed to confirm the different sperm organization between members of this superfamily and Phytophaga (Chrysomeloidea + Curculionoidea). While studying the spermiogenesis of S. kuesteri, some sperm cysts showed aberrant cells provided with two flagella in the same plasma membrane. These aberrant sperm could be the result, during early spermiogenesis, of irregular processes involving the canal rings between spermatids.

Sperm morphology of Tingidae Laporte, 1833 (Miroidea: Cimicomorpha).

Here, we describe for the first time the sperm morphology of Tingidae (Heteroptera). They are small insects presenting lacy patterns on their pronotum and hemielytra and are exclusively phytophagous, with many economically important species. We studied five species of the tribe Tingini (Tinginae): Teleonemia scrupulosa, Vatiga illudens, Gargaphia lunulata, Leptopharsa sp., and Corythucha arcuata. Their spermiogenesis process is similar to other Heteroptera, with some differences in the formation of the centriole adjunct. This structure extends in the anteroposterior spermatid axis, flanking the nucleus, possibly contributing to nucleus remodeling and sperm elongation. The mature sperm of Tingidae is also similar to that of other Heteroptera, with features that corroborate the group's monophyly. Our data support previous results for their sister family, Miridae, which exhibits some characteristics exclusive to this taxon, not present in Tingidae or other Heteroptera. They also support the sister relationship of the genera Gargaphia and Leptopharsa and suggest closer relationship between Vatiga and Corythucha. Overall, this study sheds light on the sperm ultrastructure of Tingidae and provides information for understanding the evolution and diversity of Heteroptera. RESEARCH HIGHLIGHTS: The spermiogenesis process and mature sperm are similar to other Heteroptera The centriole adjunct is derived from a strip of a pericentriolar material extending from the centriole Tingidae and Miridae are distinguishable using sperm morphology.

The sperm structure of Clinidium canaliculatum (Costa): A contribution to the systematic position of Rhysodidae (Coleoptera: Carabidae).

The systematic position and the phylogenetic relationship of Rhysodidae members is still debated, with some authors considering the group as a separate family of Adephaga, while for others they could be a subfamily of Carabidae. The group have morphological traits quite different from Carabidae and an aberrant behaviour compared to ground beetles being not predaceous. The sperm ultrastructure of C. canaliculatum was studied comparatively with other species of beetles, Carabidae in particular. The results indicate that the sperm structure of this species is similar to that of the Carabinae species. As in these species, C. canaliculatum has sperm conjugates with an apical conical cap protecting the heads and the initial region of flagella. This sperm appearance is also shared by another species of Rhysodidae, Omoglymmius hamatus. The material of the apical cap consists of an electron-dense material with a peculiar outer net configuration. Many species of Carabidae, however, can present a different type of sperm conjugation, the spermatostyle: a long rod-like structure where the individual sperms have only the most apical part inserted in the cortical area and the flagella are completely free. C. canaliculatum sperm are endowed with a mono-layered acrosome, a nucleus of variable shape along its length, a flagellum consisting of a typical axoneme 9 + 9+2, provided with 16 protofilaments in the tubular wall of accessory tubules, two asymmetric mitochondrial derivatives with the left one larger than the opposite one, and the right accessory body elongated and larger than the opposite one. These sperm characteristics, which are shared also by another member of the group, suggest the demotion of the family Rhysodidae to the subfamily Rhysodinae within Carabidae, a result also supported by recent molecular data.

A novel mini-invasive finger-prick protocol for preparing blood micro-samples for morphological analysis of human erythrocytes by scanning electron microscopy.

Here we describe the development and optimization of a new protocol for the preparation and surface imaging by scanning electron microscope of human erythrocytes from blood micro-samples obtained by finger prick. By testing several key pre-analytical conditions for blood sampling, erythrocyte preservation, storage and imaging, we designed a rapid new minimally-invasive reproducible method for obtaining uniform deposition of an adequate number of erythrocytes with well-preserved morphology on a substrate. The possibility of obtaining reliable reproducible high resolution morphometric data on peripheral erythrocytes makes this protocol valuable for diagnostic and basic research purposes.

Ultrastructure of the female reproductive organs of the diving beetle Deronectes moestus incospectus (Leprieur, 1876) (Dytiscidae, Hydroporinae).

We describe the ultrastructure of the female reproductive organs of Deronectes moestus (Dytiscidae Hydroporinae). The long spermathecal duct has a simple epithelium lined internally by a thin cuticle and externally by a thick layer of muscle cells. The wide duct lumen contains electron-dense material, among which remnants of extracellular material are visible. This material consists of tubular structures assembled around sperm bundles previously described in the male deferent ducts. The so-called gland, disposed along the spermathecal duct, is a structure with epithelial cells lined by an irregular cuticle bearing a rich system of microvilli. Many mitochondria are visible in the apical cytoplasm of the epithelial cells, and a few spheroidal bodies are close to the basal nuclei. Since the epithelial ultrastructure of the gland suggests it is involved in fluid uptake from the lumen rather than secretory activity, the term gland, coined by other authors to describe this organ, is inappropriate. The spermatheca is a large structure with a complex epithelium showing secretory and duct-forming cells. The lumen of this organ contains sperm with the distinctive ultrastructural features of those described in the male deferent ducts, namely having a mitochondrial matrix with a small crystallized area and electron-dense dots. Because to its overall organization, the spermatheca of D. moestus can be considered a more integrated organ than those in previously studied hydroporine species.

Sperm structure of the diving beetle Deronectes moestus incospectus (Leprieur, 1876) (Hydroporinae, Dytiscidae) and considerations on extracellular material surrounding sperm bundles.

The sperm cells of the diving beetle Deronectes moestus incospectus are characterized by sperm conjugation leading to the formation of sperm bundles of 64 units each. These bundles are formed at the end of spermatocyte cell divisions occurring in the testes and can be detected in the anterior region of the deferent ducts (first type of sperm conjugation). Fusions of some sperm bundles can occur at the end of the deferent ducts. The sperm bundles show sperm-head stacks (sperm rouleaux) and are surrounded by a cup of extracellular material secreted by the epithelial cells of the deferent ducts. This material extends posteriorly around the sperm bundle to cover the nuclei and the initial region of the sperm flagella. The cup extracellular material consists of fine tubules, and is no longer visible in sperm bundles at the posterior end of the deferent ducts. The sperm cells of D. moestus incospectus have an axoneme with a 9 + 9 + 2 pattern and unusual mitochondrial derivatives having a matrix showing dense dots and a small crystallized domain. Two thin elongated accessory bodies are located between the mitochondrial derivatives and the axoneme. The extracellular material can have different morphologies in the various families of Adephaga, but all are produced by the epithelium of the deferent ducts. Thus it is reasonable to assume that it has the same function in the different groups.

Dynamin-independent CaV1.2 and KCa1.1 channels regulation and vascular tone modulation by the mitochondrial fission inhibitors dynasore and dyngo-4a.

A role for mitochondrial fission in vascular contraction has been proposed based on the vasorelaxant activity of the dynamin (and mitochondrial fission) inhibitors mdivi-1 and dynasore. However, mdivi-1 is capable to inhibit Ba2+ currents through CaV1.2 channels (IBa1.2), stimulate KCa1.1 channel currents (IKCa1.1), and modulate pathways key to the maintenance of vessel active tone in a dynamin-independent manner. Using a multidisciplinary approach, the present study demonstrates that dynasore, like mdivi-1, is a bi-functional vasodilator, blocking IBa1.2 and stimulating IKCa1.1 in rat tail artery myocytes, as well as promoting relaxation of rat aorta rings pre-contracted by either high K+ or phenylephrine. Conversely, its analogue dyngo-4a, though inhibiting mitochondrial fission triggered by phenylephrine and stimulating IKCa1.1, did not affect IBa1.2 but potentiated both high K+- and phenylephrine-induced contractions. Docking and molecular dynamics simulations identified the molecular basis supporting the different activity of dynasore and dyngo-4a at CaV1.2 and KCa1.1 channels. Mito-tempol only partially counteracted the effects of dynasore and dyngo-4a on phenylephrine-induced tone. In conclusion, the present data, along with previous observations (Ahmed et al., 2022) rise caution for the use of dynasore, mdivi-1, and dyngo-4a as tools to investigate the role of mitochondrial fission in vascular contraction: to this end, a selective dynamin inhibitor and/or a different experimental approach are needed.

Fine structure of the female genital system of diving beetle Stictonectes optatus (Seidlitz, 1887) (Dytiscidae-Hydroporinae) and evidence of mating plug formation.

The general organization of the female genital system of the diving beetle Stictonectes optatus was studied, clarifying the complex structure of the spermatheca and spermathecal gland. The two structures adhere closely to each other, sharing a small area of their cuticular epithelium. A long duct connects the bursa copulatrix to the spermatheca, where the sperm are stored. The sperm reach the common oviduct, where egg fertilization occurs, via a fertilization duct. The spermathecal gland cells have extracellular cisterns where secretions are stored. Thin ducts composed of duct-forming cells transport these secretions to the apical gland region and into the spermathecal lumen. Soon after mating, the bursa copulatrix is almost completely occupied by a plug secreted by the male accessory glands. The secretions of the bursa epithelium seem to contribute to plug formation. Later this plug becomes large and spherical, obstructing the bursa copulatrix.

The Structure of the Female Genital System of the Diving Beetle Scarodytes halensis (Fabricius, 1787) (Hydroporinae, Dytiscidae), and the Organization of the Spermatheca and the Spermathecal Gland Complex.

The fine structure of the female reproductive organs of the diving beetle Scarodytes halensis has been described, with particular attention to the complex organization of the spermatheca and the spermathecal gland. These organs are fused in a single structure whose epithelium is involved in a quite different activity. The secretory cells of the spermathecal gland have a large extracellular cistern with secretions; duct-forming cells, by their efferent duct, transport the secretions up to the apical cell region where they are discharged into the gland lumen. On the contrary, the spermatheca, filled with sperm, has a quite simple epithelium, apparently not involved in secretory activity. The ultrastructure of the spermatheca is almost identical to that described in a closely related species Stictonectes optatus. Sc. halensis has a long spermathecal duct connecting the bursa copulatrix to the spermatheca-spermathecal gland complex. This duct has a thick outer layer of muscle cells. Through muscle contractions, sperm can be pushed forwarding up to the complex of the two organs. A short fertilization duct allows sperm to reach the common oviduct where eggs will be fertilized. The different organization of the genital systems of Sc. halensis and S. optatus might be related to a different reproductive strategy of the two species.

Case report: The CCDC103 variant causes ultrastructural sperm axonemal defects and total sperm immotility in a professional athlete without primary ciliary diskinesia.

Primary ciliary dyskinesia (PCD) is an inherited autosomal-recessive disorder characterized by abnormal ciliary motion, due to a defect in ciliary structure and/or function. This genetic condition leads to recurrent upper and lower respiratory infections, bronchiectasis, laterality defect, and subfertility. Male infertility is often associated with PCD, since the ultrastructure of the axoneme in the sperm tail is similar to that of the motile cilia of respiratory cells. We present the first reported case of a male patient from a non-consanguineous Italian family who exhibited a severe form of asthenozoospermia factor infertility but no situs inversus and absolutely no signs of the clinical respiratory phenotype, the proband being a professional basketball player. Whole-exome sequencing (WES) has identified a homozygote mutation (CCDC103 c.461 A>C, p.His154Pro) in the proband, while his brother was a heterozygous carrier for this mutation. Morphological and ultrastructural analyses of the axoneme in the sperm flagellum demonstrated the complete loss of both the inner and outer dynein arms (IDA and ODA, respectively). Moreover, immunofluorescence of DNAH1, which is used to check the assembly of IDA, and DNAH5, which labels ODA, demonstrated that these complexes are absent along the full length of the flagella in the spermatozoa from the proband, which was consistent with the IDA and ODA defects observed. Noteworthy, TEM analysis of the axoneme from respiratory cilia showed that dynein arms, although either IDAs and/or ODAs seldom missing on some doublets, are still partly present in each observed section. This case reports the total sperm immotility associated with the CCDC103 p.His154Pro mutation in a man with a normal respiratory phenotype and enriches the variant spectrum of ccdc103 variants and the associated clinical phenotypes in PCD, thus improving counseling of patients about their fertility and possible targeted treatments.

The sperm structure of the diving beetles Stictonectes optatus (Seidlitz, 1887) and Scarodytes halensis (Fabricius, 1787) (Dytiscidae, Hydroporinae) with evidence of a spermatostyle in the sperm conjugation.

The structure of the male genital organs and spermiogenesis of two diving beetles, Stictonectes optatus and Scarodytes halensis were studied for the first time. S. optatus shows unifollicular testes consisting of a long tubule apically forming a globular structure. The deferent duct epithelia show a secretory activity involved in the spermatostyle organization. They are connected with two very large accessory glands. Sc. halensis has a more common structure of the male genital apparatus with unifollicular cylindrical testes and very long deferent ducts. Sc. halensis accessory glands are smaller than those of S. optatus. The sperm structure in both species is characterized by a small acrosome, a flattened nucleus with a lateral extension containing a centriole from which a long flagellum originates. Both species exhibit sperm conjugation with long sperm bundles showing nuclei orderly arranged in sperm-heads stacks and free flagella. In addition, S. optatus has a thick layer of secretion surrounds these sperm-head stacks. Such a secretion is considered a spermatostyle. This finding represents the first record about the presence of this structure among Dytiscidae. In the flagellum, a typical axoneme with a 9 + 9 + 2 microtubular complex, and two mitochondrial derivatives are present in both species. Those of S. optatus have a peculiar shape with the apical side, in cross-section, displaying pointed corners. Two small accessory bodies are located between the axoneme and the two mitochondrial derivatives.

Morphology of male and female reproductive systems in the ground beetle Apotomus and the peculiar sperm ultrastructure of A. rufus (P. Rossi, 1790) (Coleoptera, Carabidae).

Relatively few studies have focused on evolutionary losses of sexually selected male traits. We use light and electron microscopy to study the male and female reproductive anatomy of Apotomus ground beetles (Coleoptera, Carabidae), a lineage that we reconstruct as likely having lost sperm conjugation, a putative sexually selected trait. We pay particular attention to the structure of the testes and spermatheca. Both of these organs share a strikingly similar shape-consisting of long blind canals arranged into several concentric overlapping rings measuring approximately 18 mm and 19.5 mm in total length, respectively. The similarity of these structures suggests a positive evolutionary correlation between female and male genital organs. Males are characterized by unifollicular testes with numerous germ cysts, which contain 64 sperm cells each, and we record a novel occurrence of sperm cyst "looping", a spermatogenic innovation previously only known from some fruit fly and Tenebrionid beetle sperm. The sperm are very long (about 2.7 mm) and include an extraordinarily long helicoidal acrosome, a short nucleus, and a long flagellum. These findings confirm the structural peculiarity of sperm, testis, and female reproductive tract (FRT) of Apotomus species relative to other ground beetles, which could possibly be the result of shifts in sexual selection.

The distal central pair segment is structurally specialised and contributes to IFT turnaround and assembly of the tip capping structures in Chlamydomonas flagella.

BACKGROUND INFORMATION: Cilia and flagella are dynamic organelles whose assembly and maintenance depend on an activetrafficking process known as the IntraFlagellar Transport (IFT), during which trains of IFT protein particles are moved by specific motors and carry flagellar precursors and turnover products along the axoneme. IFT consists of an anterograde (from base to tip) and a retrograde (from tip to base) phase. During IFT turnaround at the flagellar tip, anterograde trains release their cargoes and remodel to form the retrograde trains. Thus, turnaround is crucial for correct IFT. However, current knowledge of its mechanisms is limited. RESULTS: We show here that in Chlamydomonas flagella the distal ∼200 nm central pair (CP) segment is structurally differentiated for the presence of a ladder-like structure (LLS). During IFT turnaround, the IFT172 subunit dissociates from the IFT- B protein complex and binds to the LLS-containing CP segment, while the IFT-B complex participates in the assembly of the CP capping structures. The IFT scaffolding function played by the LLS-containing CP segment relies on anchoring components other than the CP microtubules, since IFT turnaround occurs also in the CP-devoid pf18 mutant flagella. CONCLUSIONS: During IFT turnaround in Chlamydomonas flagella, i) the LLS and the CP terminal plates act as anchoring platforms for IFT172 and the IFT-B complex, respectively, and ii) during its remodeling, the IFT-B complex contributes to the assembly of the CP capping structures. SIGNIFICANCE: Our results indicate that in full length Chlamydomonas flagella IFT remodeling occurs by a specialized mechanism that involves flagellar tip structures and is distinct from the previously proposed model in which the capability to reverse motility would be intrinsic of IFT train and independent by any other flagellar structure.

Cellular and Molecular Mechanisms of In Vivo and In Vitro SARS-CoV-2 Infection: A Lesson from Human Sperm.

Despite the major target of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, being the respiratory system, clinical evidence suggests that the male reproductive system may represent another viral target organ. Revealing the effect of SARS-CoV-2 infection on testis and sperm is a priority for reproductive biology, as well as for reproductive medicine. Here, we confirmed that the SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE2) is highly expressed on human testis and ejaculated sperm; moreover, we provide evidence for the expression of the co-receptors transmembrane protease/serine (TMPRSS2), Basigin (BSG), and Catepsin L (CTSL). Human sperm were readily infected, both in vivo and in vitro, by SARS-CoV-2, as demonstrated by confocal and electron microscopy. The demonstration that the seminiferous epithelium and sperm support SARS-CoV-2 viral replication suggests the possibility that the spermatogenetic process may be detrimentally affected by the virus, and at the same time, supports the need to implement safety measures and guidelines to ensure specific care in reproductive medicine.

The drp-1-mediated mitochondrial fission inhibitor mdivi-1 impacts the function of ion channels and pathways underpinning vascular smooth muscle tone.

Mdivi-1 is widely used as a pharmacological tool to inhibit dynamin-related protein-1-mediated mitochondrial fission. Whether this compound may interact directly or indirectly with ion channels or cellular pathways fundamental for the regulation of vascular smooth muscle tone remains unknown. The present study aimed to assess the effect of mdivi-1 on CaV1.2 and KCa1.1 channels, both in vitro and in silico as well as on the mechanical activity of rat aorta rings. Mdivi-1 was an effective CaV1.2 channel blocker, docking in a CaV1.2 channel antagonist binding region, stimulated KCa1.1 channel current, binding to a sensing region common to other stimulators, and possibly inhibited the Rho-kinase pathway. These effects contributed to its vasorelaxant activity observed in rings stimulated with high KCl, phenylephrine, or NaF. Neither structurally different dynamin inhibitors nor a stimulator affected the Ca2+ antagonistic and vasorelaxant activities of the compound. However, mito-tempol reduced its vasorelaxant potency towards phenylephrine. Finally, mdivi-1 antagonized mitochondrial fission triggered by phenylephrine. In conclusion, mdivi-1 is an effective in vitro vasorelaxant agent at concentrations routinely employed to block dynamin-related protein-1. Ion channels and pathways key to the maintenance of vessel active tone are involved in this mechanism. These yet undiscovered off-target effects raise caution for the interpretation of mitochondrial fission signalling.

New Findings on the Sperm Structure of Tenebrionoidea (Insecta, Coleoptera).

The sperm ultrastructure of a few representative species of Tenebrionoidea was studied. Two species belong to the Mordellidae (Mordellistena brevicauda and Hoshihananomia sp.), one species to Oedemeridae (Oedemera nobilis), and one species to Tenebrionidae (Accanthopus velikensis). It is confirmed that Mordellidae are characterized by the lowest number of spermatozoa per cyst (up to 64), a number shared with Ripiphoridae. In contrast, in the two other families, up to 512 spermatozoa per cyst are observed, the same number present, for example, in Tenebrionidae. Also, as in the other more derived families of tenebrionoids studied so far, during spermatogenesis in O. nobilis and A. velikensis, sperm nuclei are regularly distributed in two sets at opposite poles of the cysts. On the contrary, the Mordellidae species do not exhibit this peculiar process. However, during spermiogenesis, the bundles of sperm bend to form a loop in their median region, quite evident in the Hoshihananomia sp., characterized by long sperm. This process, which also occurs in Ripiphoridae, probably enables individuals to produce long sperm without an increase in testicular volume. The sperm looping could be a consequence of the asynchronous growth between cyst size and sperm length. The sperm ultrastructure of the Mordellidae species reveals that they can be differentiated from other Tenebrionoidea based on the shape and size of some sperm components, such as the accessory bodies and the mitochondrial derivatives. They also show an uncommon stiff and immotile posterior flagellar region provided with only accessory tubules. These results contribute to a better knowledge of the phylogenetic relationship of the basal families of the large group of Tenebrionoidea.

Homogentisic acid induces autophagy alterations leading to chondroptosis in human chondrocytes: Implications in Alkaptonuria.

Alkaptonuria (AKU) is an ultra-rare genetic disease caused by a deficient activity of the enzyme homogentisate 1,2-dioxygenase (HGD) leading to the accumulation of homogentisic acid (HGA) on connective tissues. Even though AKU is a multi-systemic disease, osteoarticular cartilage is the most affected system and the most damaged tissue by the disease. In chondrocytes, HGA causes oxidative stress dysfunctions, which induce a series of not fully characterized cellular responses. In this study, we used a human chondrocytic cell line as an AKU model to evaluate, for the first time, the effect of HGA on autophagy, the main homeostasis system in articular cartilage. Cells responded timely to HGA treatment with an increase in autophagy as a mechanism of protection. In a chronic state, HGA-induced oxidative stress decreased autophagy, and chondrocytes, unable to restore balance, activated the chondroptosis pathway. This decrease in autophagy also correlated with the accumulation of ochronotic pigment, a hallmark of AKU. Our data suggest new perspectives for understanding AKU and a mechanistic model that rationalizes the damaging role of HGA.

The sperm ultrastructure of members of basal Tenebrionoidea (Coleoptera).

The sperm ultrastructure of some beetles of Tenebrionoidea was studied with particular attention to those of the Ripiphoridae, Mordellidae, and Meloidae. These three groups are often thought to form a clade, which is the sister group of the remaining Tenebrionoidea. The testes of the two former families have thinner but longer spermatic cysts containing fewer and longer sperm. Within each cyst all sperm cells have the same orientation, but cross sections showed that the orientation of the axonemes alternate between adjacent cysts, possibly due to the cysts bending on themselves. In both families the sperm has a bilayered acrosome and the flagellum, which shows mitochondrial derivatives starting laterally to the nuclear base, has a typical 9 + 9+2 axoneme with accessory tubules provided with 16 protofilaments in their wall, and well-structured triangular shaped accessory bodies. In Mordellistena sp (Mordellidae) sperm, both mitochondrial derivatives and accessory bodies are somewhat asymmetrical. Moreover, the flagellum shows a very thin and long tail end provided with only accessory tubules. Meloidae species have testes with thicker sperm cysts containing numerous shorter sperm. Within the individual cysts the sperm flagella exhibit an alternating orientation of their axonemes as consequence of a peculiar spermatogenetic process. The flagellar structure is similar to that of the above-mentioned species, but the accessory bodies are not well defined and constituted by fuzzy material. In Mylabris hieracii (Meloidae) sperm, the acrosome is flat with a conspicuous perforatorium and its nucleus has a peculiar quadrangular section. Berberomeloe majalis sperm has a large acrosome with an unusual pentagonal perforatorium. The centriolar structure of Mylabris variabilis shows a complex of dense radial links connecting the microtubular structures to the plasma membrane. These results suggest that Ripiphoridae have a closer relationship with Mordellidae than with Meloidae. These findings are in agreement with results obtained with molecular data.

Direct evidence of the impact of aqueous self-assembly on biological behavior of amphiphilic molecules: The case study of molecular immunomodulators Sulfavants.

Sulfavant A and Sulfavant R, sulfoquinovoside-glycerol lipids under study as vaccine adjuvants, structurally differ only for the configuration of glyceridic carbon, R/S and R respectively. The in vitro activity of these substances follows a bell-shaped dose-response curve, but Sulfavant A gave the best response around 20 µM, while Sulfavant R at 10 nM. Characterization of aqueous self-assembly of these molecules by a multi-technique approach clarified the divergent and controversial biological outcome. Supramolecular structures were present at concentrations much lower than critical aggregation concentration for both products. The kind and size of these aggregates varied as a function of the concentration differently for Sulfavant A and Sulfavant R. At nanomolar range, Sulfavant A formed cohesive vesicles, while Sulfavant R arranged in spherical micellar particles whose reduced stability was probably responsible for an increase of monomer concentration in accordance with immunomodulatory profile. Instead, at micromolar concentrations transition from micellar to vesicular state of Sulfavant R occurred and thermodynamic stability of the aggregates, assessed by surface tensiometry, correlated with the bioactivity of Sulfavant A at 20 µM and the complete loss of efficacy of Sulfavant R. The study of Sulfavants provides clear evidence of how self-aggregation, often neglected, and the equilibria between monomers and aqueous supramolecular forms of lipophilic molecules deeply determine the overall bio-response.