ALBERT

Description: The cytokines interleukin-12 (IL-12) and IL-4 play important roles in the development of Th1-like (type-1) and Th2-like (type-2) T-cell responses, respectively, and there is evidence that type-1/type-2 T helper imbalances are important in the pathogenesis of human immunodeficiency virus (HIV) disease. With this background, we examined the effects of these cytokines on HIV replication. Neither stimulated HIV replication in fresh peripheral blood mononuclear cells (PBMC). However, in prestimulated PBMC, IL-12, and to a greater extent, IL-4 as well as IL-2, induced production of HIV p24 antigen over 7 days of culture (no cytokine 3,900 x/divided by 1.31 [GM x/divided by SEM] pg/mL; IL-12, 34,300 x/divided by 1.39 pg/mL; IL-4, 283,000 x/divided by 1.14 pg/mL; and IL-2, 328,000 x/divided by 1.31 pg/mL). Neither IL-12- nor IL-4-induced HIV replication was attributable to induction of IL-1, IL-2, tumor necrosis factor (TNF)-alpha, or TNF-beta. Both IL-12- and IL-4-induced HIV replication was associated with selective loss of the CD4+ subset in stimulated cultures. IL-4 stimulated HIV replication in monocyte/macrophages, while IL-12 had little or no effect in these cells. Finally, HIV replication stimulated by IL-12 or IL-4 was inhibited by dideoxynucleosides. Thus, IL-12 and IL-4 enhance HIV replication and HIV-induced cell death in prestimulated PBMC. Through killing of the CD4+ T cells stimulated by these cytokines, this may result in inappropriate type-1/type-2 responses in HIV-infected patients and contribute to their Th1 immunodeficiency.

Description: The knowledge about drug resistance in childhood leukemias and acute lymphoblastic leukemia (ALL) in general is limited. This is because of the lack of a suitable in vitro drug sensitivity assay, which is in part due to low in vitro ALL cell survival. We recently adapted the highly efficient 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay to test cells from ALL patients and showed that its results were comparable with those of the DiSC assay, up to now the most valid but laborious assay. In this study, in vitro drug sensitivity was assessed in cells from 82 children with leukemia, 79 of whom had ALL, with the MTT assay. Dose response curves were obtained for 6-mercaptopurine, 6-thioguanine (6-TG), prednisolone (Pred), daunorubicin (DNR), vincristine (VCR), cytosine arabinoside (Ara-C), L- asparaginase (L-Asp), mafosfamide, and mustine. A cytotoxic effect of methotrexate could be detected in only a few cases. Large interindividual differences in drug sensitivity were detected. Compared with leukemia cells from newly diagnosed patients, leukemia cells from relapsed patients were significantly more in vitro resistant to 6-TG, Pred, Ara-C, mafosfamide and mustine but not to DNR, VCR, and L-Asp. Improvements of culture medium and methods to increase MTT reduction were studied. From 10 components tested, addition of insulin and bovine serum albumin to serum-containing medium improved ALL cell survival. Addition of succinate did not increase the amount of MTT reduction. We conclude that the in vitro MTT assay highly facilitates large-scale studies on drug resistance of ALL patients that can lead to rational improvements in existing treatment protocols.

Description: The knowledge about drug resistance in childhood leukemias and acute lymphoblastic leukemia (ALL) in general is limited. This is because of the lack of a suitable in vitro drug sensitivity assay, which is in part due to low in vitro ALL cell survival. We recently adapted the highly efficient 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay to test cells from ALL patients and showed that its results were comparable with those of the DiSC assay, up to now the most valid but laborious assay. In this study, in vitro drug sensitivity was assessed in cells from 82 children with leukemia, 79 of whom had ALL, with the MTT assay. Dose response curves were obtained for 6-mercaptopurine, 6-thioguanine (6-TG), prednisolone (Pred), daunorubicin (DNR), vincristine (VCR), cytosine arabinoside (Ara-C), L- asparaginase (L-Asp), mafosfamide, and mustine. A cytotoxic effect of methotrexate could be detected in only a few cases. Large interindividual differences in drug sensitivity were detected. Compared with leukemia cells from newly diagnosed patients, leukemia cells from relapsed patients were significantly more in vitro resistant to 6-TG, Pred, Ara-C, mafosfamide and mustine but not to DNR, VCR, and L-Asp. Improvements of culture medium and methods to increase MTT reduction were studied. From 10 components tested, addition of insulin and bovine serum albumin to serum-containing medium improved ALL cell survival. Addition of succinate did not increase the amount of MTT reduction. We conclude that the in vitro MTT assay highly facilitates large-scale studies on drug resistance of ALL patients that can lead to rational improvements in existing treatment protocols.

Description: Background Laribacter hongkongensis is a newly discovered, facultative anaerobic, Gram-negative, motile, sea gull-shaped rod associated with freshwater fish borne gastroenteritis and traveler's diarrhea. A highly reproducible and discriminative typing system is essential for better understanding of the epidemiology of L. hongkongensis. In this study, a multilocus sequence typing (MLST) system was developed for L. hongkongensis. The system was used to characterize 146 L. hongkongensis isolates, including 39 from humans and 107 from fish. Results Fragments (362 to 504 bp) of seven housekeeping genes were amplified and sequenced. Among the 3068 bp of the seven loci, 332 polymorphic sites were observed. The median number of alleles at each locus was 34 [range 22 (ilvC) to 45 (thiC)]. All seven genes showed very low d n /d s ratios of 〈 0.04, indicating that no strong positive selective pressure is present. A total of 97 different sequence types (STs) were assigned to the 146 isolates, with 80 STs identified only once. The overall discriminatory power was 0.9861. eBURST grouped the isolates into 12 lineages, with six groups containing only isolates from fish and three groups only isolates from humans. Standardized index of association (I S A ) measurement showed significant linkage disequilibrium in isolates from both humans and fish. The I S A for the isolates from humans and fish were 0.270 and 0.636, indicating the isolates from fish were more clonal than the isolates from humans. Only one interconnected network (acnB) was detected in the split graphs. The P-value (P = 0) of sum of the squares of condensed fragments in Sawyer's test showed evidence of intragenic recombination in the rho, acnB and thiC loci, but the P-value (P = 1) of maximum condensed fragment in these gene loci did not show evidence of intragenic recombination. Congruence analysis showed that all the pairwise comparisons of the 7 MLST loci were incongruent, indicating that recombination played a substantial role in the evolution of L. hongkongensis. A website for L. hongkongensis MLST was set up and can be accessed at http://mlstdb.hku.hk:14206/MLST_index.html. Conclusion A highly reproducible and discriminative MLST system was developed for L. hongkongensis.

Description: Polar ecosystems are experiencing amongst the most rapid rates of regional warming on Earth. Here, we discuss ‘omics’ approaches to investigate polar biodiversity, including the current state of the art, future perspectives and recommendations. We propose a community road map to generate and more fully exploit multi-omics data from polar organisms. These data are needed for the comprehensive evaluation of polar biodiversity and to reveal how life evolved and adapted to permanently cold environments with extreme seasonality. We argue that concerted action is required to mitigate the impact of warming on polar ecosystems via conservation efforts, to sustainably manage these unique habitats and their ecosystem services, and for the sustainable bioprospecting of novel genes and compounds for societal gain.

Description: 〈span〉〈div〉Abstract〈/div〉Pyromorphite-group minerals (PyGM), mainly pyromorphite [Pb〈sub〉5〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉Cl], mimetite [Pb〈sub〉5〈/sub〉(AsO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉Cl], and vanadinite [Pb〈sub〉5〈/sub〉(VO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉Cl], are common phases that form by supergene weathering of galena. Their formation is strongly influenced by processes at the Earth's surface and in the soil overlying a lead deposit, and they incorporate high amounts of halogens, mostly Cl and, in some cases, F. The abundance of Br and I in natural PyGM and their potential as process tracers during surface and sub-surface fluid-rock interaction processes has not been investigated in detail due to analytical difficulties. We, therefore, developed methods for the simultaneous determination of Cl, F, Br, and I in PyGM for (1) powdered bulk samples via combustion ion chromatography (CIC) and (2) compositionally zoned crystals by means of secondary ion mass spectrometry (SIMS).Our study is based on well-characterized samples of pyromorphite (N = 38), mimetite (N = 16), and vanadinite (N = 2) from Schwarzwald (Germany). Natural pyromorphite incorporates more I (up to 26 μg/g) than mimetite (up to 2 μg/g) and vanadinite (up to 1 μg/g), while Br contents are higher in mimetite (up to 20 μg/g) and vanadinite (up to 13 μg/g) compared to pyromorphite (less than 4 μg/g). These results are unexpected, as mimetite and vanadinite have longer As/V-O bonds giving them larger unit cells and larger polyhedral volumes for the Cl site in the Pb2〈sub〉6〈/sub〉 octahedron than pyromorphite. Accordingly, pyromorphite was expected to preferentially incorporate Br rather than I, but the opposite is observed. Hence, halogen chemistry of PyGM is probably not governed by a crystal-chemical control (alone) but by fluid composition. However, the exact reasons remain enigmatic. This idea is corroborated by spatially resolved SIMS analyses that show that many pyromorphite-group minerals are strongly zoned with respect to their halogen mass ratios (e.g., Br/Cl, Br/I mass ratios). Furthermore, variations in halogen abundance ratios do not correlate with Ca/Pb, P/As, or P/V ratios and therefore may record alternating and season-dependent environmental parameters including biological activity, vegetation density, physico-chemical soil properties, and rainfall rate. We suggest that the zonation reflects multiple single fluid flow episodes and, hence, records surface processes. However, further experiments concerning the fractionation of halogens between fluid and PyGM are needed before halogen ratios in pyromorphite-group minerals can be used as reliable monitors of fluid-driven processes.〈/span〉

Description: 〈span〉〈div〉ABSTRACT〈/div〉Characterizing earthquake ground motions through 3D simulations is becoming standard practice for seismic hazard assessment in urbanized regions. However, accurate ground‐motion predictions require shear‐wave velocity (VS) data at depths that capture the extent of the sedimentary column (usually greater than 30 m), which can be difficult to obtain. We acquired microtremor array data at 11 sites in the Seattle basin, Washington, and applied the wavenumber‐normalized spatial autocorrelation (SPAC) method (krSPAC) to obtain VS at depths as great as 2200 m. In a traditional SPAC approach, modeling high wavenumbers within the SPAC spectrum requires array symmetry. By contrast, in the krSPAC approach we transform observed coherency versus frequency spectra to coherency versus kr (in which k and r are wavenumber and station separation, respectively) prior to VS modeling. Through this transformation, the requirement for array symmetry is eased. We deployed seven‐sensor nested irregular triangular arrays, with nominal interstation spacings that varied from about 300 to 2000 m. Comparison of VS derived from krSPAC to a previous interpretation from ambient‐noise tomography studies suggests a broadly comparable VS structure in the 250–1000 m depth range with improved resolution at shallower depth. At each site, we interpret a high‐velocity Quaternary boundary in which VS increases above 900  m/s. Using this boundary as the reference horizon, we calculate ground‐motion amplification of a factor of up to 2 from the overlying Quaternary sediments between 0.3 and 7 Hz, assuming vertically propagating 〈span〉S〈/span〉 waves.〈/span〉