Analysis of Sertoli Cell-Secreted Proteins by Two-Dimensional Gel Electrophoresis

The [35S]methionine-labeled proteins secreted from cultured Sertoli cells were analyzed by two-dimensional gel electrophoresis and fluorography. Major polypeptides which were resolved by this procedure were designated by number and further analyzed. Many of these major polypeptides appeared as a series of spots which corresponded to charge isomers. Two of these polypeptides (5 and 6) were shown to be acidic, glycosylated and to comprise the subunits of a dimeric protein of molecular weight 70,000. Some of the polypeptides (4a and 5a) were shown to be secreted from testicular peritubular cells which contaminated the Sertoli cell cultures. However, many of the polypeptides (1,2,3,4,5,5b and 6) were specifically secreted from the Sertoli cells. The fluorogram of the secreted polypeptides obtained from cultured Sertoli cells from 20- or 60-day-old rats were similar to each other but differed from the pattern of polypeptides which were secreted from cultures of Sertoli cells from 10-day-old rats. Polypeptide 3 was identified by immunoprecipitation as testicular transferrin and the synthesis of polypeptide 3 was stimulated when the Sertoli cells were cultured in the presence of follicle-stimulating hormone (FSH), insulin, testosterone and retinol

Ablation of an Ovarian Tumor Family Deubiquitinase Exposes the Underlying Regulation Governing the Plasticity of Cell Cycle Progression in \u3cem\u3eToxoplasma gondii\u3c/em\u3e

The Toxoplasma genome encodes the capacity for distinct architectures underlying cell cycle progression in a life cycle stage-dependent manner. Replication in intermediate hosts occurs by endodyogeny, whereas a hybrid of schizogony and endopolygeny occurs in the gut of the definitive feline host. Here, we characterize the consequence of the loss of a cell cycle-regulated ovarian tumor (OTU family) deubiquitinase, OTUD3A of Toxoplasma gondii (TgOTUD3A; TGGT1_258780), in T. gondii tachyzoites. Rather than the mutation being detrimental, mutant parasites exhibited a fitness advantage, outcompeting the wild type. This phenotype was due to roughly one-third of TgOTUD3A-knockout (TgOTUD3A-KO) tachyzoites exhibiting deviations from endodyogeny by employing replication strategies that produced 3, 4, or 5 viable progeny within a gravid mother instead of the usual 2. We established the mechanistic basis underlying these altered replication strategies to be a dysregulation of centrosome duplication, causing a transient loss of stoichiometry between the inner and outer cores that resulted in a failure to terminate S phase at the attainment of 2N ploidy and/or the decoupling of mitosis and cytokinesis. The resulting dysregulation manifested as deviations in the normal transitions from S phase to mitosis (S/M) (endopolygeny-like) or M phase to cytokinesis (M/C) (schizogony-like). Notably, these imbalances are corrected prior to cytokinesis, resulting in the generation of normal progeny. Our findings suggest that decisions regarding the utilization of specific cell cycle architectures are controlled by a ubiquitin-mediated mechanism that is dependent on the absolute threshold levels of an as-yet-unknown target(s). Analysis of the TgOTUD3A-KO mutant provides new insights into mechanisms underlying the plasticity of apicomplexan cell cycle architecture

Non-Sexual Transmission of Trichomonas vaginalis in Adolescent Girls Attending School in Ndola, Zambia

OBJECTIVES: To identify risk factors for trichomoniasis among young women in Ndola, Zambia. METHOD: The study was a cross-sectional study among adolescent girls aged 13-16 years in Ndola, Zambia. Study participants were recruited from schools in selected administrative areas that represented the different socio-economic strata in town. Consenting participants were interviewed about their socio-demographic characteristics; sexual behaviour; and hygiene practices. Self-administered vaginal swabs were tested for Trichomonas vaginalis. HSV-2 antibodies were determined on serum to validate the self-reported sexual activity. RESULTS: A total of 460 girls participated in the study. The overall prevalence of trichomoniasis was 27.1%, 33.9% among girls who reported that they had ever had sex and 24.7% among virgins. In multivariate analysis the only statistically significant risk factor for trichomoniasis was inconsistent use of soap. For the virgins, none of the risk factors was significantly associated with trichomoniasis, but the association with use of soap (not always versus always) and type of toilet used (pit latrine/bush versus flush toilet) was of borderline significance. CONCLUSION: We found a high prevalence of trichomoniasis in girls in Ndola who reported that they had never had sex. We postulate that the high prevalence of trichomoniasis in virgins in Ndola is due to non-sexual transmission of trichomoniasis via shared bathing water and inconsistent use of soap

Pyrolysis of medium-density fiberboard: optimized search for kinetics scheme and parameters via a genetic algorithm driven by Kissinger's method

The pyrolysis kinetics of charring materials plays an important role in understanding material combustions especially for construction materials with complex degradation chemistry. Thermogravimetric analysis (TGA) is frequently used to study the heterogeneous kinetics of solid fuels; however, there is no agreed method to determine the pyrolysis scheme and kinetic parameters for charring polymers with multiple components and competing reaction pathways. This study develops a new technique to estimate the possible numbers of species and sub-reactions in pyrolysis by analyzing the second derivatives of thermogravimetry (DDTG) curves. The pyrolysis of a medium-density fiberboard (MDF) in nitrogen is studied in detail, and the DDTG curves are used to locate the temperature of the peak mass-loss rate for each sub-reaction. Then, on the basis of the TG data under multiple heating rates, Kissinger’s method is used to quickly find the possible range of values of the kinetic parameters (<i>A</i> and <i>E</i>). These ranges are used to accelerate the optimization of the inverse problem using a genetic algorithm (GA) for the kinetic and stoichiometric parameters. The proposed method and kinetic scheme found are shown to match the experimental data and are able to predict accurately results at different heating rates better than Kissinger’s method. Moreover, the search method (K–K method) is highly efficient, faster than the regular GA search alone. Modeling results show that, as the TG data available increase, the interdependence among kinetic parameters becomes weak and the accuracy of the first-order model declines. Furthermore, conducting TG experiment under multiple heating rates is found to be crucial in obtaining good kinetic parameters

A critical review of smaller state diplomacy

In The Peloponnesian War, Thucydides (1972: 402) highlights the effects of the general, overall weakness of smaller states vis-à-vis larger, more powerful ones in a key passage, where the Athenians remind the Melians that: “… since you know as well as we do that, as the world goes, right is only in question between equals in power. Meanwhile, the strong do what they can and the weak suffer what they must.” Concerns about the vulnerability of small, weak, isolated states have echoed throughout history: from Thucydides, through the review by Machiavelli (1985) of the risks of inviting great powers to intervene in domestic affairs, through 20th century US-led contemporary political science (Vital, 1971; Handel, 1990) and Commonwealth led scholarship (Commonwealth Secretariat, 1985). In the context of 20th century ‘Balkanization’, the small state could also prove unstable, even hostile and uncooperative, a situation tempting enough to invite the intrusion of more powerful neighbours: a combination, according to Brzezinski (1997: 123-124) of a power vacuum and a corollary power suction2: in the outcome, if the small state is ‘absorbed’, it would be its fault, and its destiny, in the grand scheme of things. In an excellent review of small states in the context of the global politics of development, Payne (2004: 623, 634) concludes that “vulnerabilities rather than opportunities are the most striking consequence of smallness”. It has been recently claimed that, since they cannot defend or represent themselves adequately, small states “lack real independence, which makes them suboptimal participants in the international system” (Hagalin, 2005: 1). There is however, a less notable and acknowledged but more extraordinary strand of argumentation that considers ‘the power of powerlessness’, and the ability of small states to exploit their smaller size in a variety of ways in order to achieve their intended, even if unlikely, policy outcomes. The pursuance of smaller state goals becomes paradoxically acceptable and achievable precisely because such smaller states do not have the power to leverage disputants or pursue their own agenda. A case in point concerns the smallest state of all, the Vatican, whose powers are both unique and ambiguous, but certainly not insignificant (The Economist, 2007). Smaller states have “punched above their weight” (e.g. Edis, 1991); and, intermittently, political scientists confront their “amazing intractability” (e.g. Suhrke, 1973: 508). Henry Kissinger (1982: 172) referred to this stance, with obvious contempt, as “the tyranny of the weak”3. This paper seeks a safe passage through these two, equally reductionist, propositions. It deliberately focuses first on a comparative case analysis of two, distinct ‘small state-big state’ contests drawn from the 1970s, seeking to infer and tease out the conditions that enable smaller ‘Lilliputian’ states (whether often or rarely) to beat their respective Goliaths. The discussion is then taken forward to examine whether similar tactics can work in relation to contemporary concerns with environmental vulnerability, with a focus on two other, small island states. Before that, the semiotics of ‘the small state’ need to be explored, since they are suggestive of the perceptions and expectations that are harboured by decision makers at home and abroad and which tend towards the self-fulfilling prophecy.peer-reviewe

TriTrypDB: a functional genomic resource for the Trypanosomatidae

TriTrypDB (http://tritrypdb.org) is an integrated database providing access to genome-scale datasets for kinetoplastid parasites, and supporting a variety of complex queries driven by research and development needs. TriTrypDB is a collaborative project, utilizing the GUS/WDK computational infrastructure developed by the Eukaryotic Pathogen Bioinformatics Resource Center (EuPathDB.org) to integrate genome annotation and analyses from GeneDB and elsewhere with a wide variety of functional genomics datasets made available by members of the global research community, often pre-publication. Currently, TriTrypDB integrates datasets from Leishmania braziliensis, L. infantum, L. major, L. tarentolae, Trypanosoma brucei and T. cruzi. Users may examine individual genes or chromosomal spans in their genomic context, including syntenic alignments with other kinetoplastid organisms. Data within TriTrypDB can be interrogated utilizing a sophisticated search strategy system that enables a user to construct complex queries combining multiple data types. All search strategies are stored, allowing future access and integrated searches. ‘User Comments’ may be added to any gene page, enhancing available annotation; such comments become immediately searchable via the text search, and are forwarded to curators for incorporation into the reference annotation when appropriate