Nuclear changes during spermiogenesis in two chrysomelid beetles

Ultrastructural and cytochemical studies were carried out on sperm nucleus of the beetles,Coelomera lanio and Diabrotica speciosa. Nuclear development involves changes in the shape and in the degree of chromatin condensation, with specific aggregation patterns of DNAhistone complex occurring during this process. Lamellar and paracrystalline arrangements of the nuclear material were observed in the Diabrotica speciosa spermatid and in the Coelomera lanio spermatozoon, respectively. Ethanolic-phosphotungstic acid technique suggest the presence of basic proteins in the nuclear material of spermatids. This reaction disappears during chromatin condensation. Chromatin condensation patterns may reflect specific intranuclear mechanisms and offers protection to the genome during spermatozoon transport to the oocyte

Nanobiotechnology for Breast Cancer Treatment

Despite many technological breakthroughs, even the best breast cancer treatments available today are not 100% effective. Chemotherapy has improved, but many drugs still do not reach the tumor site at effective doses and are often associated with high systemic toxicity and poor pharmacokinetics. Moreover, for many malignancies, diagnosis is obtainable only in metastatic stages of development, reducing the overall effectiveness of treatment. The choice of available treatments depends on tumor characteristics such as biomarkers, tumor size, metastatic disease, ligands, and antigen or endocrine receptor expression. Combined with surgical resection, chemotherapy and radiation remain the first line of treatment for patients with cancer. Even with these treatments, however, cancer continues to have high fatality rates and current therapeutic modalities have yet to significantly improve the often dismal prognosis of this disease. Nanotechnology is a highly focused approach, which may provide more effective and less toxic treatment when compared to chemotherapy. This area of research has emerged as cancer treatment in the form of new drugs and has reached promising results in preclinical and clinical trials proving its value as a potential tumor therapy

Effects of chronic exposure to soy meal containing diet or soy derived isoflavones supplement on semen production and reproductive system of male rabbits

Soy and derivative diets deliver large doses of isoflavones to human and animals throughout their lifespan, including gestation. Epidemiologic and experimental data suggest that the consumption of soybean containing foods may protect against cardiovascular disease and decrease breast, prostate and endometrial cancer risk. Based on animal and in vitro studies, however, concerns have been raised that consumption of isoflavones may cause potential adverse effects on the reproductive tract and behavior. The aim of this study was to investigate the effects of chronic consumption of a soy meal containing diet or soy isoflavones supplement on the morphology of reproductive organs, semen quality, age that males reached puberty, and sexual behavior of male rabbits. With this purpose, 16 female rabbits were randomly assigned to receive: (1) a soy- and alfafa-free diet; (2) a soy- and alfafa-free diet supplemented with 5 mg/kg body wt./day of soy isoflavones; (3) a soy- and alfafa-free diet supplemented with 20 mg/kg body wt./day of soy isoflavones; (4) a diet containing 18% of soy meal, throughout the gestation and lactation. After weaning, male offspring received the same diet, which was given to the respective mother. The age that males reached puberty, semen characteristics and sexual behavior were evaluated in these animals. At 33 weeks of age, the reproductive organs were submitted to histological evaluation. Rabbits, which received large amounts of isoflavones (20 mg/kg body wt./day) had a lesser food intake, body weight and semen volume. Spermatogenesis, morphology of male genital organs and sexual behavior did not differ significantly from the control group. We conclude that chronic dietary treatment with soy based diet or soy isoflavones have no adverse effects on the observed reproductive patterns of male rabbits

Sperm ultrastructure of the honey bee (Apis mellifera) (L) (Hymenoptera, Apidae) with emphasis on the nucleus-flagellum transition region

The flagellum of Apis mellifera (Hymenoptera, Apidae) consists of two mitochondrial derivatives, an axoneme and two accessory bodies. The mitochondrial derivatives are of unequal size and lie parallel to the axoneme. In the larger derivative four regions can be distinguished while in the smaller, only three. The region occurring only in the larger derivative consists of paracystalline material. The smaller mitochondrial derivative terminates anterior to the larger one. An extremely long centriolar adjunct is observed between the nucleus and the smaller mitochondrial derivative. This adjunct is compact, very electron dense and gradually tapers from base toward apex, finishing at the anterior extremity of the axonemal microtubules. In this flagellar region, there is only one accessory body present between the larger mitochondrial derivative and the axoneme. Anteriorly, the tips of the axonemal microtubules are inserted in a well developed mass of granular appearance. This material surrounds the nuclear base, separating it from the anterior end of the larger mitochondrial derivative. We believe that the structure identified here as a centriolar adjunct is homologous to that observed in Formicidae, Ichneumonoidea and Symphyta. Therefore, very probably, it is common to most Hymenoptera

Ultrastructural description and cytochemical study of the spermatozoon of Crotallus durissus (Squamata, Serpentes)

The present study was undertaken to elucidate some aspects about the nature of the spermatozoon ultrastructure of Crotallus durissus using cytochemical methods. We also provide for the first time the ultrastructural description of this species spermatozoon. Cytochemical studies of spermatozoa have not been performed so far in the Serpentes, and species spermatozoon may prove helpful to better understand the reproductive biology of this group. Besides the synapomorphies of the Squamata and Serpentes, the C. durissus spermatozoon possess the following: circular acrosome tip; rounded perforatorium tip with a stopper-like basal modification; bilateral stratified laminar structures; central electron-dense structure within the proximal centriole; fibrous sheath extending until the level of the second mitochondrial ring; rounded mitochondria in cross-section, but with variable shape and organization in longitudinal and oblique sections, respectively; linear annulus; developed multilaminar membranes in the nuclear region and the midpiece. The formation of membrane filipin–sterol complexes occur sparsely along the head region, specially around the nucleus; the complexes were also present in the midpiece membrane and scarcely lining the flagellum. The complexes were present in the different layers of the multilaminar membranes. The ethanol-phosphotungstic acid (E-PTA) treatment releaved the presence of basic proteins in acrosome vesicle, pericentriolar material, peripheral fibers of the axoneme and fibrous sheath. The tannic acid technique revealed the microtubules of the centrioles and the axoneme; the extracellular tubules encircling the spermatozoa and those spread in the epididymal lumen were also observed. However, the immunocytochemistry assay using antibodies against alpha-tubulin and beta-tubulin, the primary microtubule monomers, does not support the existence of composition similarity between these tubular structures, since the extracellular tubules were not labeled by the antibodies. The results obtained in this work demonstrate that the utilization of electron microscopic techniques may provide relevant information to the study of ophidian reproductive biology, particularly in analyses concerning spermatozoal ultrastructure

Structural and ultrastructural characterization of male reproductive tracts and spermatozoa in fig wasps of the genus Pegoscapus (Hymenoptera, Chalcidoidea)

The three Pegoscapus species present the same internal reproductive tract features comprising testes with a single testicular tubule, seminal vesicles, vasa deferentia, accessory glands and an ejaculatory duct. The seminal vesicle shows two morphologically distinct portions although they do not resemble the separate chambers found in other Chalcidoidea. The anterior portion of the seminal vesicle shows a prominent epithelium and stores the mature spermatozoa, while the posterior region is formed by a thicker muscular sheath that participates on ejaculation. The sexual maturation in Pegoscapus is achieved at emergence, when the testicular degeneration occurs. The spermatozoa of Pegoscapus reveal a basic structure similar to that of other Chalcidoidea. In Pegoscapus sp1. and Pegoscapus sp2. they present the same features, whereas Pegoscapus tonduzi comprises some different characteristics. It measures approximately 160 μm in Pegoscapus sp1. and Pegoscapus sp2., while in P. tonduzi the spermatozoa measure about 360 μm. The extracellular sheath thickness is another difference among the species. While Pegoscapus sp1. and Pegoscapus sp2. show a thick extracellular sheath, in P. tonduzi this sheath is very thin resulting in a large space intervening between the extracellular sheath and the nucleus. Despite these differences, the three species analyzed share some characteristics that allow the establishment of an identity to the spermatozoon of the genus Pegoscapus: the seminal vesicle not divided in chambers; the absence of acrosomal structures in the spermatozoa; the length of the extracellular sheath; the central microtubules being the firsts to terminate in the sequence of microtubular cutoff at the final axonemal portion

Immunocytochemical localization of tubulins in spermatids and spermatozoa of Euptoieta hegesia (Lepidoptera : Nymphalidae)

A comparative analysis of the distribution of tubulin types in apyrene and eupyrene sperm of Euptoieta hegesia butterflies was carried out, also verifying the presence of tubulin in lacinate appendages of the eupyrene sperm. Ultrathin sections of LR White embedded spermatids and spermatozoa were labeled for alpha, beta, gamma, alpha-acetylated and alpha-tyrosinated tubulins. Apyrene and eupyrene spermatids show the same antibody recognition pattern for tubulins. All tubulin types were detected in axonemal microtubules. Alpha and gamma tubulins were also detected on the cytoplasmic microtubules. However, for beta and tyrosinated tubulins only scattered labeling was detected on cytoplasmic microtubules and acetylated tubulin was not detected. In apyrene and eupyrene spermatozoa only the axoneme labeling was analyzed since cytoplasmic microtubules no longer exist in these cells. Alpha, beta and tyrosinated tubulins were easily detected on the apyrene and eupyrene axoneme; gamma tubulin was strongly marked on eupyrene axonemes but was scattered on the apyrene ones. Acetylated tubulin appeared with scattered labeling on the axoneme of both sperm types. Our results demonstrate significant differences in tubulin distribution in apyrene and eupyrene axonemal and cytoplasmic microtubules. Extracellular structures, especially the lacinate appendages, were not labeled by antibodies for any tubulin

Ultrastructural localization of enzymatic activity during spermiogenesis in two phytophagous bugs (Hemiptera: Pentatomidae)

Ultrastructural cytochemical techniques were used for the localization of phosphatases and oxidases in spermatid and spermatozoon of the phytophagous bugs Acrosternum aseadum and Nezara viridula (Hemiptera: Pentatomidae). Acid phosphatase was found mainly in the trans most portion of the Golgi complex, and in the acrosome of spermatozoon. Glucose-6-phosphatase was located in the endoplasmic reticulum, trans portion of the Golgi complex and in the acrosome of spermatids. The axoneme showed activity of acid phosphatase, glucose-6-phosphatase and thiamine pyrophosphatase. This observation supports the idea that various phosphates may play some role in spermatid differentiation. Indeed, the presence of cytochrome oxidase activity was only shown in the mitochondrial cristae of early spermatids, suggesting also the participation of this enzyme during spermatid differentiation of this insect

Structural specialization in the flagellum of the spermatozoon of the bloodsucking bug (Rhodnius prolixus; Hemiptera, Reduviidae)

Spermatozoa of the triatomideo Rhodnius prolixus possess an axoneme with a 9 + 9 + 2 microtubule pattern and two mitochondrial derivatives. Bridges occur between axoneme and mitochondrial derivatives. Two paracrystalline structures embedded in amorphous regions were observed in the mitochondrial derivative. The use of the negative staining technique shows a zig-zag profile in the mitochondrial derivatives due to infolding to the cristae, regularly spaced with approximately 50 nm. This spacing is also observed in the distribution of the strands of particles in the mitochondrial membrana as seen in freeze-fracture replicas. In the P-fracture face of the flagellar plasma membrane, a regular array of the intramembranous particles was observed. This array consists of two rows, with 12–15 particles, and occurs in the space between the mitochondrial derivatives. Thus R. prolixus spermatozoon present a membrane domain, localized in the flagellar region, and bridges between mitochondrial membrane derivatives and the plasma membrane are probably attached to the flagellar components. These membrane specializations may be related to the production of co-ordinated flagellar movement, and can contribute significantly to further phylogenetic studies