Replication of Deoxyribonucleic Acid During the Division Cycle of Salmonella typhimurium

The rate of thymidine incorporation into cells of Salmonella typhimurium growing in different media has been measured. In glucose-minimal medium, deoxyribonucleic acid (DNA) replication occurs during the first two-thirds of the division cycle; the final one-third of the division cycle was devoid of DNA replication. The measured doubling time of S. typhimurium in this medium is approximately 48 min, indicating that C (the time for a round of replication) and D (the time between termination and cell division) are approximately 32 and 16 min, respectively. At slower growth rates the pattern of replication is the same as glucose minimal medium. At faster growth rates the "gap" in DNA synthesis disappears. At rapid growth rates evidence for multiple forks is obtained.     

EVOLUTION OF MULTIPLE KINDS OF FEMALE SPERM-STORAGE ORGANS IN DROSOPHILA

Females of all species belonging to the family Drosophilidae have two kinds of sperm-storage organs: paired spherical spermathecae and a single elongate tubular seminal receptacle. We examined 113 species belonging to the genus Drosophila and closely allied genera and describe variation in female sperm-storage organ use and morphology. The macroevolutionary pattern of organ dysfunction and morphological divergence suggests that ancestrally both kinds of organs stored sperm. Loss of use of the spermathecae has evolved at least 13 times; evolutionary regain of spermathecal function has rarely if ever occurred. Loss of use of the seminal receptacle has likely occurred only once; in this case, all descendant species possess unusually elaborate spermathecae. Data further indicate that the seminal receptacle is the primary sperm-storage organ in Drosophila. This organ exhibits a pattern of strong correlated evolution with the length of sperm. The evolution of multiple kinds of female sperm-storage organs and the rapidly divergent and correlated evolution of sperm and female reproductive tract morphology are discussed.     

Cell allocation and chromosomal complement of parthenogenetic and IVF bovine embryos

Considerable concerns exist regarding the quality of parthenogenetically activated embryos in terms of sufficient numbers of cells comprising the inner cell mass (ICM) and trophectoderm (TE) and the ploidy. Therefore, these two parameters were used to assess the quality of embryos derived from parthenogenetic activation by using calcium ionophore A23187 (CaI) followed by either 6‐dimethylaminopurine (6‐DMAP, 3.5 hr or 6.5 hr) or cycloheximide (CHX) plus cytochalasin D (CD). The conventional in vitro (IVF) produced embryos served as a control. Double staining of the parthenogenetic blastocysts showed that the total cell number (TC) of embryos from the 6‐DMAP 3.5 hr (87.0 ± 5.3) and CHX+CD (79.0 ± 6.1) groups was not different (P > 0.05), but was lower than that of control embryos (116.0 ± 5.8, P < 0.001). The mean ratios of inner cell mass (ICM) and trophectoderm (TE) cells in the 6‐DMAP 3.5 hr group (0.57 ± 0.04) and the control IVF group (0.50 ± 0.02) did not differ significantly. Both were higher than those of the CHX+CD group (0.36 ± 0.02; P < 0.05). Further analysis of chromosomal compositions of developing stage embryos at day four after IVF or parthenogenetic activation demonstrated that prolonged treatment with 6‐DMAP for 6.5 hr resulted in a significantly lower percentage of diploid embryos and a significantly higher percentage of abnormal ploidy embryos compared to treatment with 6‐DMAP for 3.5 hr or with CHX and IVF. In conclusion, parthenogenetic activation of bovine oocytes with CaI followed by 6‐DMAP for 3.5 hr could produce better quality embryos in terms of total cell numbers, the number of cells allocated to the ICM, and the ploidy of embryos. Mol. Reprod. Dev. 54:57–62, 1999. © 1999 Wiley‐Liss, Inc.     

Acts and practices of citizenship: Muslim women’s activism in the UK

Drawing on the growing literature on Muslim women’s activism, this paper explores grammars of action that frame political mobilizations of Muslim women in the UK. By taking a broad view of political activism, we identify acts and practices of citizenship through which Muslim women activists engage with, reinterpret and challenge social norms. The article critically engages with dominant readings of post-migration minorities’ political mobilization through the lens of citizenship regimes and draws attention to more processual and agency-centred perspectives on citizenship. We focus on two salient themes that Bristol-based Muslim activists were concerned with: mobilizing against violence against women, manifested in the anti-FGM campaign by Integrate Bristol, and attempts to re-negotiate the terms of participation in religious spaces, manifested in claims for more inclusive mosques. In both instances, mobilization was not confined to the local community or national level, but supported by and embedded in related transnational struggles.     

Landscape of nuclear transport receptor cargo specificity

Nuclear transport receptors (NTRs) recognize localization signals of cargos to facilitate their passage across the central channel of nuclear pore complexes (NPCs). About 30 different NTRs constitute different transport pathways in humans and bind to a multitude of different cargos. The exact cargo spectrum of the majority of NTRs, their specificity and even the extent to which active nucleocytoplasmic transport contributes to protein localization remains understudied because of the transient nature of these interactions and the wide dynamic range of cargo concentrations. To systematically map cargo–NTR relationships in situ, we used proximity ligation coupled to mass spectrometry (BioID). We systematically fused the engineered biotin ligase BirA* to 16 NTRs. We estimate that a considerable fraction of the human proteome is subject to active nuclear transport. We quantified the specificity and redundancy in NTR interactions and identified transport pathways for cargos. We extended the BioID method by the direct identification of biotinylation sites. This approach enabled us to identify interaction interfaces and to discriminate direct versus piggyback transport mechanisms. Data are available via ProteomeXchange with identifier PXD007976.     

Lipid, ketone body and oxidative metabolism in the African lungfish, Protopterus dolloi following 60 days of fasting and aestivation

The potential importance of lipids and ketone bodies as fuels in the African lungfish, Protopterus dolloi, and the role of oxidative metabolism, were examined under control, fasted and aestivated conditions. In aestivating but not fasting lungfish, the activities of citrate synthase (CS) and cytochrome c oxidase (CCO) (enzymes of oxidative metabolism) showed tissue-specific changes. Significant reductions in CS activity occurred in the kidney, heart, gill and muscle, and in CCO in the liver and kidney tissues. Aestivation, but not fasting, also had a tissue-specific effect on mitochondrial state 3 respiration rates (using succinate as a substrate), with a >50% reduction in the liver, yet no change within muscle mitochondria. There is no indication that enzymes involved in lipid catabolism are up-regulated during periods of fasting or aestivation; however, both 3-hydroxyacyl CoA dehydrogenase (HOAD) and carnitine palmitoyl CoA transferase (CPT) activities were sustained in the liver despite the approximately 42% reduction in CCO activity, potentially indicating lipid metabolism is of importance during aestivation. Lungfish are able to utilize both the d- and l-stereoisomers of the ketone body beta-hydroxybutyrate (beta-HB); however, beta-HB does not appear to be an important fuel source during aestivation or fasting as no changes were observed in beta-HB tissue levels. This study demonstrates that an important aspect of metabolic depression during aestivation in lungfish is the tissue-specific down regulation of enzymes of aerobic metabolism while maintaining the activities of enzymes in pathways that supply substrates for aerobic metabolism.     

Comparative proteomics of human monkeypox and vaccinia intracellular mature and extracellular enveloped virions.

Orthopoxviruses are among the largest and most complex of the animal viruses. In response to the recent emergence of monkeypox in Africa and the threat of smallpox bioterrorism, two orthopoxviruses with different pathogenic potentials, human monkeypox virus and vaccinia virus, were proteomically compared with the goal of identifying proteins required for pathogenesis. Orthopoxviruses were grown in HeLa cells to two different viral forms (intracellular mature virus and extracellular enveloped virus), purified by sucrose gradient ultracentrifugation, denatured using RapiGest surfactant, and digested with trypsin. Unfractionated samples and strong cation exchange HPLC fractions were analyzed by high-resolution reversed-phase nano-LC-MS/MS, and analyses of the MS/MS spectra using SEQUEST and X! Tandem resulted in the confident identification of hundreds of monkeypox, vaccinia, and copurified host-cell proteins. The unfractionated samples were additionally analyzed by LC-MS using an LTQ-Orbitrap, and the accurate mass and elution time tag approach was used to perform quantitative comparisons. Possible pathophysiological roles of differentially abundant Orthopoxvirus proteins are discussed. Data, processed results, and protocols are available at http://www.proteomicsresource.org/.     

Differential regulation of RhoA-mediated signaling by the TPalpha and TPbeta isoforms of the human thromboxane A2 receptor: independent modulation of TPalpha signaling by prostacyclin and nitric oxide

In humans, thromboxane (TX) A(2) signals through the TPalpha and TPbeta isoforms of the TXA(2) receptor that exhibit common and distinct roles. For example, Gq/phospholipase (PL)Cbeta signaling by TPalpha is directly inhibited by the vasodilators prostacyclin and nitric oxide (NO) whereas that signaling by TPbeta is unaffected. Herein, we investigated whether TPalpha and/or TPbeta regulate G(12)/Rho activation and whether that signaling might be differentially regulated by prostacyclin and/or NO. Both TPalpha and TPbeta independently regulated RhoA activation and signaling in clonal cells over-expressing TPalpha or TPbeta and in primary human aortic smooth muscle cells (1 degrees AoSMCs). While RhoA-signaling by TPalpha was directly impaired by prostacyclin and NO through protein kinase (PK)A- and PKG-dependent phosphorylation, respectively, signaling by TPbeta was not directly affected by either agent. Collectively, while TPalpha and TPbeta contribute to RhoA activation, our findings support the hypothesis that TPalpha is involved in the dynamic regulation of haemostasis and vascular tone, such as in response to prostacyclin and NO. Conversely, the role of TPbeta in such processes remains unsolved. Data herein provide essential new insights into the physiologic roles of TPalpha and TPbeta and, through studies in AoSMCs, reveal an additional mode of regulation of VSM contractile responses by TXA(2).