Effects of capsaicin on testis ghrelin expression in mice

Capsaicin (CAP), the active substance of red hot peppers, has been reported to stimulate development of the gonad. Ghrelin is an acylated polypeptide hormone that is secreted predominantly by endocrine cells of the stomach. There is evidence that ghrelin is involved in reproductive function. Ghrelin significantly inhibits testosterone secretion in a dose-dependent manner. We investigated the effect of CAP on ghrelin expression in testes of mice and on testosterone levels during pubertal and adult periods. We used a variety of morphometric, immunohistochemical and biochemical methods, and western blot analysis. The animals were divided into two age groups: puberty and adult. Control groups for both age groups were fed with standard diet and experimental groups were fed with a diet containing 0.02% CAP. Testes were collected quickly after sacrifice. After dehydration, the specimens were embedded in paraffin and 5 μm sections were cut, and Crossman's triple staining and immunohistochemical staining for ghrelin were applied. Immunohistochemical staining with ghrelin antibody for both age groups demonstrated immunoreaction especially in Leydig and Sertoli cells, but no reaction was observed in spermatogenic cells. Ghrelin immunoreaction was less intense in the experimental groups. Serum testosterone levels were increased in both experimental groups, especially in adults. More spermatocytes were observed in the experimental group compared to the control group. In both pubertal and adult experimental groups, the seminiferous epithelium was thick. CAP appears to enhance testicular cell proliferation and can affect the release of ghrelin and testosterone directly or indirectly.

Cellular distribution, regulated expression, and functional role of the anorexigenic peptide, NUCB2/nesfatin-1, in the testis

Nesfatin-1, product of the precursor NEFA/nucleobindin2 (NUCB2), was initially identified as anorectic hypothalamic neuropeptide, acting in a leptin-independent manner. In addition to its central role in the control of energy homeostasis, evidence has mounted recently that nesfatin-1 is also produced in peripheral metabolic tissues, such as pancreas, adipose, and gut. Moreover, nesfatin-1 has been shown to participate in the control of body functions gated by whole-body energy homeostasis, including puberty onset. Yet, whether, as is the case for other metabolic neuropeptides, NUCB2/nesfatin-1 participates in the direct control of gonadal function remains unexplored. We document here for the first time the expression of NUCB2 mRNA in rat, mouse, and human testes, where NUCB2/nesfatin-1 protein was identified in interstitial mature Leydig cells. Yet in rats, NUCB2/nesfatin-1 became expressed in Sertoli cells upon Leydig cell elimination and was also detected in Leydig cell progenitors. Although NUCB2 mRNA levels did not overtly change in rat testis during pubertal maturation and after short-term fasting, NUCB2/nesfatin-1 content significantly increased along the puberty-to-adult transition and was markedly suppressed after fasting. In addition, testicular NUCB2/nesfatin-1 expression was up-regulated by pituitary LH, because hypophysectomy decreased, whereas human choriogonadotropin (super-agonist of LH receptors) replacement enhanced, NUCB2/nesfatin-1 mRNA and peptide levels. Finally, nesfatin-1 increased human choriogonadotropin-stimulated testosterone secretion by rat testicular explants ex vivo. Our data are the first to disclose the presence and functional role of NUCB2/nesfatin-1 in the testis, where its expression is regulated by developmental, metabolic, and hormonal cues as well as by Leydig cell-derived factors. Our observations expand the reproductive dimension of nesfatin-1, which may operate directly at the testicular level to link energy homeostasis, puberty onset, and gonadal function.

Detection of Theileria annulata in cattle and vector ticks by PCR using the Tams1 gene sequences

A Polymerase Chain Reaction (PCR) and Southern blot hybridization for the detection of Theileria annulata are described. The PCR used primers amplifying a 785 base-pair fragment of the T. annulata gene which encodes the 30 kDa major merozoite surface antigen, Tams1. The sensitivity of the PCR in bovine blood was 1 piroplasm in 1 microl of blood. T. buffeli, T. parva, Babesia bigemina, B. bovis and B. divergens were not detected. The PCR detected down to 1 infected acinus/tick in resting and partially fed adult Hyalomma anatolicum anatolicum ticks and was negative for T. lestoquardi and T. equi, which are transmitted by this tick but are not infective to cattle. The specificity of the PCR was checked using 30 stocks of T. annulata, all of which were detected. Three stocks of T. lestoquardi, 4 of T. equi and 1 each of T. buffeli, T. parva, B. bigemina, B. bovis and B. divergens were used to ascertain there were no cross-reactions. A nested PCR using separate primers for the first reaction and the same primers for the second reaction detected T. annulata to the same sensitivity and specificity in saponin-extracted DNA samples stored for long periods at -20 degrees C.

Mechanism(s) of attenuation of Theileria annulata vaccine cell lines

Attenuated vaccines are an important means of controlling Theileria annulata infection of cattle. Production is by prolonged cultivation of macroschizont-infected cells. The mechanism of attenuation remains unclear. There are three general nonmutually exclusive possibilities: Selection of avirulent subpopulations, genome rearrangements and alterations in gene expression. Several groups, including ours, have provided evidence that the population structure usually tends to simplify during attenuation. Our data on the T. annulata (Ta) Ankara cell line show that attenuation is not necessarily accompanied by the population becoming clonal. We have been unable to detect large DNA rearrangements. Evidence for alterations in host and parasite gene expression during attenuation is available. With respect to the host we have shown that attenuation is accompanied by loss of expression of parasite induced matrix metalloproteinases (MMPs). However, in different lines different protease activities are involved. In the T. annulata Ode line we have shown that 8 activities (including MMP9) are downregulated and that this correlates with a loss of metastatic behaviour. This has previously been shown in vitro using reconstituted basement membrane (Matrigel) and is demonstrated in vivo using scid mice in this study. Thus part of the pathology, namely the ability to disseminate, mediated by host MMPs, is lost upon attenuation. Re-isolation experiments have shown that the reduction/loss of MMP is a stable transferable trait. A logical extension is that loss of MMP activity (and virulence in general) must be at the most fundamental level a genetic trait of the parasite. Evidence for loss of parasite gene expression is implied by the loss of the ability to differentiate into merozoites on attenuation. Specific evidence for loss of parasite gene expression has been obtained using differential RNA display. We view virulence as a multifactorial phenomenon involving interacting subpopulations of cells and attenuation is a threshold effect whereby the number of virulence factors is reduced below a critical level. On this basis there will be many different ways to achieve attenuation.

Theileria lestoquardi and T. annulata in cattle, sheep, and goats. In vitro and in vivo studies

Theileria annulata, causing bovine tropical theileriosis, and T. lestoquardi (syn T. hirci), the agent of malignant ovine theileriosis, are both transmitted by ticks of the genus Hyalomma. Their distribution is thus very similar and, should these parasites infect more than one ruminant species, the difficulty in interpreting epidemiological studies is magnified considerably. A pilot series of experiments was thus conducted in which cattle, sheep and goats were infected with sporozoites of a single stock of each of T. annulata and T. lestoquardi from a laboratory colony of H.a.anatolicum. Reciprocal cross-immunity and serological studies and in vitro culture isolations in mononuclear cells of each ruminant species illustrated both the similarity of these organisms and their differences. The importance of these findings in discriminating parasites in epidemiological studies and the control of these diseases with cell culture vaccines is emphasized.

Detection of Theileria lestoquardi (hirci) in ticks, sheep, and goats using the polymerase chain reaction

Theileria lestoquardi (= T. hirci) is a protozoan parasite of sheep and goats that is morphologically and biologically similar to T. annulata, the causative agent of bovine tropical theileriosis. Both parasites are transmitted by ixodid ticks of the genus Hyalomma. However, because of their morphological similarity, they cannot be distinguished in the salivary glands of infected ticks by traditional staining methods such as Feulgen or Methyl green-pyronin. Thus a need has arisen for sensitive and specific diagnostic tests that will distinguish between the two species in the vector tick, allowing the epidemiology of both diseases to be clearly defined. A contribution to this has been the development of a polymerase chain reaction using specific primers which amplify, only in T. lestoquardi-infected ticks, a 785 bp fragment of the gene that codes for a 30 kD merozoite surface protein. The sensitivity of this test and its application to the detection of T. lestoquardi in infected H. anatolicum anatolicum ticks, in the blood of three species of domestic ruminants and in cell cultures established in mononuclear cells of sheep and goats is also discussed.

Theileria annulata: carrier state and immunity

Recovery from primary infection of Theileria annulata results in the development of a persistent carrier state in the vertebrate host. The carrier state is of great importance in the maintenance of the life cycle by alternate tick/cattle challenge and both contributes to and may be necessary for maintenance of immunity. Therefore, an accurate determination of carrier animals could be useful in determining immune status and may allow the necessary control measures to be implemented. Detailed information on the carrier state of animals following immunization with attenuated cell lines is lacking. In this study, relationship between immune response, persistence of the parasite, and the antibody response has been investigated. Calves were infected with T. annulata sporozoites, low passage (non-attenuated) or high passage (attenuated, vaccine) cell lines and later challenged with a lethal dose of heterologous sporozoites. The presence and persistence of the parasite were monitored by PCR using primers derived from genes coding for ssrRNA and a 30 kDa major merozoite surface protein, by Giemsa stained blood smears to detect the presence of piroplasms and also by attempting to establish infected mononuclear cell cultures from venous blood. Antibody responses were measured by indirect ELISA using a merozoite recombinant antigen and IFAT using piroplasm and macroschizont antigens. Results showed that there was an evident relationship between the persistence of carrier status, antibody response in ELISA and immune response to challenge.