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41.
D Williamson I J McLennan A Bax M P Gamcsik J D Glickson 《Journal of biomolecular structure & dynamics》1990,8(2):375-398
Two-dimensional NMR experiments--one bond 1H-13C correlation spectroscopy and heteronuclear multiple bond correlation spectroscopy, both performed in the reverse detection mode--have been employed to unambiguously assign all of the 13C resonances of the antibiotic bleomycin and its zinc(II) complex. Previous 1H resonance assignments of bleomycin (Chen et al. (1977) Biochemistry 16, 2731-2738) were confirmed on the basis of homonuclear Hartmann-Hahn and homonuclear COSY experiments. The 13C assignments differ substantially from those previously obtained by other investigators (Naganawa et al., (1977) J. Antibiot. 30, 388-396; Dabrowiak et al., (1978) Biochemistry 17, 4090-4096) but are in agreement with those reported by Akkerman et al. (1988) (Magn. Reson. Chem. 26, 793-802). The more recent study employed similar two-dimensional correlation experiments (performed in the direct detection mode) in conjunction with attached proton tests. Their study often required model compound data to identify carbonyls adjacent to aliphatic moieties. Previous 13C NMR studies of the structure, pH titration, and molecular dynamics of bleomycin and its zinc complex have been reinterpreted in terms of the revised assignments. 相似文献
42.
Mallory E. Eckstut Caleb D. McMahan Brian I. Crother Justin M. Ancheta Deborah A. McLennan Daniel R. Brooks 《Global Ecology and Biogeography》2011,20(4):545-557
Aim To compare the evolutionary and ecological patterns of two extensively studied island biotas with differing geological histories (the Hawaiian Islands and the Greater Antilles). We evaluated the results from PACT (phylogenetic analysis for comparing trees), an innovative approach that has been proposed to reveal general patterns of biotic expansion (between regions) and in situ (within a region) diversification, as well as species–area relationships (SAR) and the taxon pulse dynamic. Location The Hawaiian Islands and Greater Antilles. Methods We used the PACT algorithm to construct general area cladograms and identified biotic expansion and in situ nodes. We analysed the power‐law SAR and relative contribution of biotic expansion and in situ diversification events using power‐law and linear regression analyses. Results Both biotic expansion and in situ nodes were prevalent throughout the PACT general area cladograms (Greater Antilles, 55.9% biotic expansion, 44.1% in situ; Hawaiian Islands, 40.6% biotic expansion, 59.4% in situ). Of the biotic expansion events, both forward and backward events occurred in both regions (Greater Antilles, 85.1% forward, 14.9% backward; Hawaiian Islands, 65% forward, 35% backward). Additionally, there is a power‐law SAR for the Greater Antilles but not for the Hawaiian Islands. However, exclusion of Hawai'i (the youngest, largest Hawaiian Island) produced a power‐law SAR for the Hawaiian Islands. Main conclusions The prevalence of in situ events as well as forward and backward biotic expansion events reveals that both Hawaiian and Greater Antillean biotas have evolved through alternating episodes of biotic expansion and in situ diversification. These patterns are characteristic of the taxon pulse dynamic, for which few data have previously been recorded on islands. Additionally, our analysis revealed that historical influences on the power‐law SARs are pronounced in both assemblages: old, small islands are relatively species rich and young, large islands are relatively species poor. Thus, our PACT results are consistent with hypotheses of geological influence on the evolution of island biotas and also provide greater insight into the role of the taxon pulse dynamic in the formation of island equilibria. 相似文献
43.
Matthew R. McLennan Noemi Spagnoletti Kimberley J. Hockings 《International journal of primatology》2017,38(2):105-121
People are an inescapable aspect of most environments inhabited by nonhuman primates today. Consequently, interest has grown in how primates adjust their behavior to live in anthropogenic habitats. However, our understanding of primate behavioral flexibility and the degree to which it will enable primates to survive alongside people in the long term remains limited. This Special Issue brings together a collection of papers that extend our knowledge of this subject. In this introduction, we first review the literature to identify past and present trends in research and then introduce the contributions to this Special Issue. Our literature review confirms that publications on primate behavior in anthropogenic habitats, including interactions with people, increased markedly since the 2000s. Publications concern a diversity of primates but include only 17% of currently recognized species, with certain primates overrepresented in studies, e.g., chimpanzees and macaques. Primates exhibit behavioral flexibility in anthropogenic habitats in various ways, most commonly documented as dietary adjustments, i.e., incorporation of human foods including agricultural crops and provisioned items, and as differences in activity, ranging, grouping patterns, and social organization, associated with changing anthropogenic factors. Publications are more likely to include information on negative rather than positive or neutral interactions between humans and primates. The contributions to this Special Issue include both empirical research and reviews that examine various aspects of the human–primate interface. Collectively, they show that primate behavior in shared landscapes does not always conflict with human interests, and demonstrate the value of examining behavior from a cost–benefit perspective without making prior assumptions concerning the nature of interactions. Careful interdisciplinary research has the potential to greatly improve our understanding of the complexities of human–primate interactions, and is crucial for identifying appropriate mechanisms to enable sustainable human–primate coexistence in the 21st century and beyond. 相似文献
44.
S. Devin McLennan Lauren A. Peterson Joan B. Rose 《Applied and environmental microbiology》2009,75(22):7283-7286
Four point-of-use disinfection technologies for treating sewage-contaminated well water were compared. Three systems, based on flocculant-disinfectant packets and N-halamine chlorine and bromine contact disinfectants, provided a range of 4.0 to >6.6 log10 reductions (LR) of naturally occurring fecal indicator and heterotrophic bacteria and a range of 0.9 to >1.9 LR of coliphage.Disasters and flooding can overwhelm sanitation infrastructure, leading to sewage contamination of potable waters. This may be routine during the wet season in many parts of the world and spreads numerous waterborne diseases (21). Point-of-use (POU) water treatment has reduced the incidence of diarrheal disease when used for household drinking water (3, 4, 6, 13) and is now being promoted for disaster relief. While POU systems have recently been reviewed (14), to our knowledge there has been no direct, experimental comparison for treating actual sewage-contaminated waters. In this study, the efficacies of four POU disinfection systems (based on sodium dichloroisocyanurate [NaDCC] tablets, a flocculent-disinfectant powder, and chlorine and bromine contact disinfectant cartridges) in reducing the concentrations of six microbial indicators in well water contaminated with raw sewage were compared.The NaDCC tablets (67 mg; Aquatabs; Medentech, Wexford, Ireland), used for disinfection in low-turbidity water, have shown preliminary efficacy for routine household drinking water treatment (3, 4). The flocculant-disinfectant packet (4 g; PUR; Procter & Gamble Co., Cincinnati, OH) includes Fe2(SO4)3, bentonite, Na2CO3, chitosan, polyacrylamide, KMnO4, and Ca(OCl)2 (13). It achieved >7.3 log10 reductions (LR) of 24 bacteria species; >4.6 LR of poliovirus and rotavirus in EPA no. 2 test water (turbidity, >30 nephelometric turbidity units [NTU]) (15); and reduced diarrheal illness in Guatemala, Liberia, Kenya, and Pakistan (6, 7, 11, 13).HaloPure canisters (Eureka Forbes, Mumbai, India) contain N-halamine polymer disinfectant beads, poly[1,2-dichloro-5-methyl-5-(4′-vinylphenyl)hydrantoin] for chlorine canisters, and poly[1,2-dibromo-5-methyl-5-(4′-vinylphenyl)hydrantoin] for bromine canisters. Seeded laboratory trials achieved >6.8 LR for Escherichia coli and Staphylococcus aureus as water was passed through the canisters (2). The Cl-contact (producing residuals ranging from 0 to 0.6 mg/liter) and Br-contact (with residuals of 0.68 to 1.8 mg/liter) disinfectants achieved 2.9 LR and 5.0 LR of the bacteriophage MS2, respectively, and 27.5% and 88.5% reductions of the algal toxin microcystin, respectively (5).Sewage-contaminated water was prepared by mixing 9 liters of potable, nonchlorinated well water (pH 7.8; turbidity, 0.33 NTU; Williamston, MI) with 1 liter of raw sewage (City of East Lansing Wastewater Treatment Plant, MI) with an average pH of 6.6 ± 0.1, a biochemical oxygen demand of 144 ± 36 mg/liter, a concentration of total suspended solids of 146 ± 31 mg/liter, and a turbidity of 132 ± 12 NTU. Three disinfection trials were conducted at room temperature for each POU system on three different days to allow for variance in sewage strength. The turbidities of 1:10 dilutions of raw sewage averaged 7.5 ± 2.0 NTU. Table Table11 lists the indicator microorganism concentrations in the influent and effluent for each system.
Open in a separate windowaValues shown are numbers of CFU/ml except those for coliphage, which are numbers of PFU/ml. The percentage of samples below the detection limit (n = 3 for all systems) is 0% if not shown.All systems were used in accordance with the manufacturer''s directions for 10 liters of water. For NaDCC trials, one tablet was added and allowed 30 min of contact time (total dose of 3.2 mg/liter of hypochlorite; in deionized water, one tablet produced 2.1 mg/liter free Cl residual). For flocculant-disinfectant trials, one packet was added, stirred vigorously for 5 min, strained through cheesecloth after 10 min, and allowed 20 min of further contact time. The amount of hypochlorite included in one packet was not indicated, but one packet provided 1.5 mg/liter free Cl residual in 10 liters of deionized water. Samples were taken at 1, 3, 5, 10, 15, and 30 min for both systems.For the Cl-contact and Br-contact trials, disinfectant cartridges were installed in AquaSure housings consisting of an upper reservoir for influent, which flows by gravity through the disinfectant cartridge to a lower reservoir with a tap for dispensing (Fig. (Fig.1).1). The housings usually include cloth and activated charcoal prefilters, but these were removed in order to directly evaluate the disinfectant. With the tap open, 10 liters of influent was added and samples were collected at first flow (6 to 12 min) and after 15 and 30 min of flow. A single chlorine canister was used for all trials; the bromine canister was replaced for the third trial because the original clogged.Open in a separate windowFIG. 1.Flow schematic for contact disinfectant cartridges. Arrows indicate the directions of water flow from the upper reservoir (U), through the halogen (chlorine or bromine) disinfectant cartridge (H) containing packed N-halamine beads (N), to the lower reservoir (L) and out through the open tap.Microbial indicators in the influent and effluent (collection tubes contained sodium thiosulfate) in triplicate were quantified as numbers of CFU/ml by using mENDO agar for total coliforms (9), mHPC agar for heterotrophic plate counts (8), mTEC medium for E. coli (19), mEI agar for the genus Enterococcus (18), and mCP agar for the genus Clostridium (1) (Becton, Dickinson and Co., Franklin Lakes, NJ). Coliphage (PFU/ml) were measured with a double agar overlay assay, EPA method 1601 (17). Residuals (mg/liter) were measured using a Hach chlorine (free and total) test kit, model CN66 (Hach Co., Loveland, CO) (used for bromine in accordance with Hach method 8016 [10], with the instrument reading multiplied by 2.25 [the ratio of the atomic weights of bromine and chlorine], as advised by Hach Co. technical support).Comparison of water quality levels was done at 30 minutes. LR were calculated, with zeros replaced with the detection limits (Fig. (Fig.2).2). All POU systems reduced microbial concentrations below the detection limit in some trials (Table (Table1),1), making the calculated reductions the lower bound for those trials.Open in a separate windowFIG. 2.Average LR of naturally occurring microorganisms at 30 min for sewage-contaminated well water (1:10 dilution of raw sewage in well water) with the use of four POU disinfection systems (error bars represent 1 standard error). * indicates that effluent was below the limit of detection for all samples. Limit of detection was substituted to calculate LR and actual reductions may be greater than shown.Average LR for each POU system were compared using two-way analysis of variance with post hoc least-significant-difference (LSD) tests, performed with SPSS 11.0.1 (SPSS, Inc.). LR at 30 min differed significantly between systems (analysis of variance; F3,5 = 20.6; P < 0.001). There was no significant difference between the LR achieved by flocculant-disinfectant and contact disinfectants (LSD; mean difference, 0.2 to 0.5 LR; P > 0.05), while the NaDCC tablets induced significantly lower reductions (LSD; mean difference, 1.5 to 2.0 LR; P < 0.001).There was detectable residual free chlorine after 30 min for one NaDCC trial (0.4 mg/liter) and two flocculant-disinfectant trials (0.1 and 0.4 mg/liter). No contact disinfectant trial produced a measurable residual.No system in this study reliably produced residuals for safe storage after POU treatment or ideal virus reduction. Except for the NaDCC system, the POU systems achieved approximately 5.5 LR for E. coli and coliforms, 4.5 LR for enterococci, 4.0 LR for heterotrophs, 2.5 LR for clostridia, and 1.0 LR for coliphage. Coliphage was reduced below detection limits in all trials with Br-contact, similar to what was found in previous research (5). Bromine disinfection has proved safe and effective for large-scale maritime applications, like U.S. Navy vessels (20), and appears promising for household treatment. Further assessment of the Br-contact system is warranted, as is field comparison of POU systems in disaster relief. 相似文献
TABLE 1.
Concentrations of influent and 30-min-effluent microorganisms for POU disinfectant systems treating sewage-contaminated waterMicroorganism group | Geometric mean concn (range) [% of samples below detection limit]a | |||||||
---|---|---|---|---|---|---|---|---|
NaDCC | Flocculant-disinfectant | Cl-contact | Br-contact | |||||
Influent | Effluent at 30 min | Influent | Effluent at 30 min | Influent | Effluent at 30 min | Influent | Effluent at 30 min | |
Total coliforms | 2.7 × 104 (6.7 × 103 to 7.6 × 104) | 4.3 (4.0 × 10−2 to 1.6 × 102) | 1.7 × 104 (1.2 × 104 to 2.7 × 104) | 4.0 × 10−2 (<1.0 × 10−2 to 2.4 × 10−1) [33] | 2.9 × 104 (2.3 × 104 to 4.0 × 104) | <1.0 × 10−2 [100] | 4.5 × 104 (1.9 × 104 to 7.2 × 104) | 1.1 × 10−2 (<1.0 × 10−2 to 1.3 × 10−2) [66] |
Heterotrophic plate counts | 8.7 × 104 (2.7 × 104 to 1.8 × 105) | 6.4 × 101 (2.1 × 101 to 4.5 × 102) | 8.9 × 104 (2.9 × 104 to 4.3 × 105) | 8.5 (4.7 to 2.7 × 101) | 6.6 × 104 (3.5 × 104 to 1.1 × 105) | 3.9 (3.5 to 4.2) | 8.3 × 104 (2.4 × 104 to 2.0 × 105) | 4.6 (2.2 to 7.7) |
E. coli | 3.3 × 103 (7.7 × 102 to 1.1 × 104) | 1.8 × 101 (9.0 × 10−1 to 5.3 × 102) | 6.7 × 103 (2.3 × 103 to 4.3 × 104) | 1.1 × 10−2 (<1.0 × 10−2 to 1.3 × 10−2) [66] | 4.7 × 103 (2.3 × 103 to 1.1 × 104) | <1.0 × 10−2 [100] | 1.5 × 104 (6.3 × 103 to 4.6 × 104) | <1.0 × 10−2 [100] |
Enterococci | 8.8 × 102 (5.7 × 102 to 1.3 × 103) | 2.3 (<1.0 × 10−2 to 4.9 × 101) [33] | 6.3 × 102 (5.0 × 102 to 8.7 × 102) | <1.0 × 10−2 [100] | 9.9 × 102 (5.3 × 102 to 1.7 × 103) | <1.0 × 10−2 [100] | 1.3 × 103 (7.3 × 102 to 2.3 × 103) | <1.0 × 10−2 [100] |
Clostridia | 1.6 × 102 (6.0 × 101 to 3.0 × 102) | 6.4 (6.7 × 10−1 to 7.7 × 101) | 2.0 × 102 (7.0 × 101 to 6.0 × 102) | 7.9 × 10−1 (4.5 × 10−1 to 1.4) | 3.4 × 101 (2.0 × 101 to 6.3 × 101) | 2.4 × 10−2 (<1.0 × 10−2 to 6.0 × 10−2) [33] | 4.4 × 101 (2.7 × 101 to 9.3 × 101) | 7.4 × 10−2 (<1.0 × 10−2 to 3.6 × 10−1) [33] |
Coliphage | 1.5 × 102 (1.2 × 102 to 2.2 × 102) | 3.1 × 101 (<1.0 to 1.8 × 102) [33] | 1.4 × 102 (1.3 × 102 to 1.4 × 102) | 1.9 × 101 (<1.0 to 1.1 × 102) [33] | 9.4 × 101 (4.3 × 101 to 1.6 × 102) | 7.3 (1.3 to 4.7 × 101) | 7.7 × 101 (4.0 × 101 to 1.2 × 102) | <1.0 [100] |
45.
Michael F McNitt-Gray Luc M Bidaut Samuel G Armato III Charles R Meyer Marios A Gavrielides Charles Fenimore Geoffrey McLennan Nicholas Petrick Binsheng Zhao Anthony P Reeves Reinhard Beichel Hyun-Jung Kim Lisa Kinnard 《Translational oncology》2009,2(4):216-222
RATIONALE AND OBJECTIVES: This article describes issues and methods that are specific to the measurement of change in tumor volume as measured from computed tomographic (CT) images and how these would relate to the establishment of CT tumor volumetrics as a biomarker of patient response to therapy. The primary focus is on the measurement of lung tumors, but the approach should be generalizable to other anatomic regions. MATERIALS AND METHODS: The first issues addressed are the various sources of bias and variance in the measurement of tumor volumes, which are discussed in the context of measurement variation and its impact on the early detection of response to therapy. RESULTS AND RESOURCES: Research that seeks to identify the magnitude of some of these sources of error is ongoing, and several of these efforts are described herein. In addition, several resources for these investigations are being made available through the National Institutes of Health-funded Reference Image Database to Evaluate Response to therapy in cancer project, and these are described as well. Other measures derived from CT image data that might be predictive of patient response are described briefly, as well as the additional issues that each of these metrics may encounter in real-life applications. CONCLUSIONS: The article concludes with a brief discussion of moving from the assessment of measurement variation to the steps necessary to establish the efficacy of a metric as a biomarker for response. 相似文献
46.
47.
Paul M Kulesa Jessica M Teddy Miranda Smith Richard Alexander Cameron HJ Cooper Rusty Lansford Rebecca McLennan 《BMC developmental biology》2010,10(1):101
Background
Tracing cell dynamics in the embryo becomes tremendously difficult when cell trajectories cross in space and time and tissue density obscure individual cell borders. Here, we used the chick neural crest (NC) as a model to test multicolor cell labeling and multispectral confocal imaging strategies to overcome these roadblocks. 相似文献48.
49.
50.
The g5R (D250) gene of African swine fever virus encodes a Nudix hydrolase that preferentially degrades diphosphoinositol polyphosphates. 下载免费PDF全文
Jared L Cartwright Stephen T Safrany Linda K Dixon Edward Darzynkiewicz Janusz Stepinski Richard Burke Alexander G McLennan 《Journal of virology》2002,76(3):1415-1421
The African swine fever virus (ASFV) g5R gene encodes a protein containing a Nudix hydrolase motif which in terms of sequence appears most closely related to the mammalian diadenosine tetraphosphate (Ap4A) hydrolases. However, purified recombinant g5R protein (g5Rp) showed a much wider range of nucleotide substrate specificity compared to eukaryotic Ap4A hydrolases, having highest activity with GTP, followed by adenosine 5'-pentaphosphate (p5A) and dGTP. Diadenosine and diguanosine nucleotides were substrates, but the enzyme showed no activity with cap analogues such as 7mGp3A. In common with eukaryotic diadenosine hexaphosphate (Ap6A) hydrolases, which prefer higher-order polyphosphates as substrates, g5Rp also hydrolyzes the diphosphoinositol polyphosphates PP-InsP5 and [PP]2-InsP4. A comparison of the kinetics of substrate utilization showed that the k(cat)/K(m) ratio for PP-InsP5 is 60-fold higher than that for GTP, which allows classification of g5R as a novel diphosphoinositol polyphosphate phosphohydrolase (DIPP). Unlike mammalian DIPP, g5Rp appeared to preferentially remove the 5-beta-phosphate from both PP-InsP5 and [PP]2-InsP4. ASFV infection led to a reduction in the levels of PP-InsP5, ATP and GTP by ca. 50% at late times postinfection. The measured intracellular concentrations of these compounds were comparable to the respective K(m) values of g5Rp, suggesting that one or all of these may be substrates for g5Rp during ASFV infection. Transfection of ASFV-infected Vero cells with a plasmid encoding epitope-tagged g5Rp suggested localization of this protein in the rough endoplasmic reticulum. These results suggest a possible role for g5Rp in regulating a stage of viral morphogenesis involving diphosphoinositol polyphosphate-mediated membrane trafficking. 相似文献