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101.
Wittkowski M Mittelstädt J Brandau S Reiling N Lindner B Torrelles J Brennan PJ Holst O 《The Journal of biological chemistry》2007,282(26):19103-19112
The capsules of two colony morphotypes of Mycobacterium avium strain 2151 were investigated, i.e. the virulent smooth-transparent (SmT1) and the nonvirulent smooth-opaque (SmO) types. From both morphotypes we separated a nonacylated arabinomannan (AM) from an acylated polysaccharide fraction by affinity chromatography, of which the AMs were structurally characterized. The AMs from the virulent morphotype, in contrast to that from the nonvirulent form, possessed a larger mannan chain and a shorter arabinan chain. Incubation of murine bone marrow-derived macrophages and human dendritic cells showed that the acylated polysaccharide fractions were potent inducers of tumor necrosis factor-alpha, interleukin-12, and interleukin-10 compared with nonacylated AMs, which led to only a marginal cytokine release. Further in vitro experiments showed that both the acylated polysaccharide fractions and the nonacylated AMs were able to induce in vitro anti-tumor cytotoxicity of human peripheral blood mononuclear cells. Thus, morphotype-specific structural differences in the capsular AMs of M. avium do not correlate with biological activity; however, their acylation is a prerequisite for effective stimulation of murine macrophages and human dendritic cells. 相似文献
102.
Morrison BH Bauer JA Lupica JA Tang Z Schmidt H DiDonato JA Lindner DJ 《The Journal of biological chemistry》2007,282(21):15349-15356
We previously showed that inositol hexakisphosphate kinase 2 (IHPK2) functions as a growth-suppressive and apoptosis-enhancing kinase during cell stress. Overexpression of IHPK2 sensitized ovarian carcinoma cell lines to the growth-suppressive and apoptotic effects of interferon beta (IFN-beta), IFN-alpha2, and gamma-irradiation. Expression of a kinase-dead mutant abrogated 50% of the apoptosis induced by IFN-beta. Because the kinase-dead mutant retained significant response to cell stressors, we hypothesized that a portion of the death-promoting function of IHPK2 was independent of its kinase activity. We now demonstrate that IHPK2 binds to tumor necrosis factor (TNF) receptor-associated factor (TRAF) 2 and interferes with phosphorylation of transforming growth factor beta-activated kinase 1 (TAK1), thereby inhibiting NF-kappaB signaling. IHPK2 contains two sites required for TRAF2 binding, Ser-347 and Ser-359. Compared with wild type IHPK2-transfected cells, cells expressing S347A and S359A mutations displayed 3.5-fold greater TAK1 activation following TNF-alpha. This mutant demonstrated a 6-10-fold increase in NF-kappaB DNA binding following TNF-alpha compared with wild type IHPK2-expressing cells in which NF-kappaB DNA binding was inhibited. Cells transfected with wild type IHPK2 or IHPK2 mutants that lacked S347A and S359A mutations displayed enhanced terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling staining following TNF-alpha. We believe that IHPK2-TRAF2 binding leads to attenuation of TAK1- and NF-kappaB-mediated signaling and is partially responsible for the apoptotic activity of IHPK2. 相似文献
103.
LAURA M. BOYKIN RUTH ANN BAGNALL DONALD R. FROHLICH DAVID G. HALL WAYNE B. HUNTER CATHERINE S. KATSAR CINDY L. MCKENZIE ROSEMARIE C. ROSELL ROBERT G. SHATTERS JR. 《Molecular ecology resources》2007,7(6):1202-1204
Twelve polymorphic microsatellite markers were developed from microsatellite‐enriched DNA libraries and mined from an expressed sequence tags library of Diaphorina citri, the vector of the citrus greening disease (huanglongbing). Analysis of 288 individuals from Florida, Texas, and Brazil showed that allelic diversity ranged from three to eight alleles per locus and observed and expected heterozygosities ranged from 0.014 to 0.569 and from 0.052 to 0.653, respectively. These variable microsatellite loci can provide means for assessing overall genetic variation and migration patterns for this agriculturally important pest species. This information can be used to aid in developing successful management strategies. 相似文献
104.
SHOIL M. GREENBERG GRETCHEN D. JONES FRANK EISCHEN RANDY J. COLEMAN JOHN J. ADAMCZYK JR. TONG-XIAN LIU MAMOUDOU SETAMOU 《Insect Science》2007,14(6):503-510
The survival of overwintering boll weevil, Anthonomus grandis grandis (Boheman), adults on non-cotton hosts in the Lower Rio Grande Valley (LRGV) of Texas was examined from 2001 to 2006. The success of the Boll Weevil Eradication Program, which was reintroduced into the LRGV in 2005, depends on controlling overwintering boll weevil populations. Laboratory studies were conducted using boll weevil adults that were captured in pheromone traps from September through March. The number of adults captured per trap declined significantly in the field from fall to the beginning of spring (3.5-7.0-fold). The proportion of trapped males and females did not differ significantly. The mean weight of boll weevil adults captured in September was 13.3 mg, while those of captured adults from November to February were significantly lower and ranged from 6.7 to 7.8 mg. Our results show that boll weevil adults can feed on different plant pollens. The highest longevity occurred when adults were fed almond pollen or mixed pollens (72.6 days and 69.2 days, respectively) and the lowest when they fed on citrus pollen or a non-food source (9.7 days or 7.4 days, respectively). The highest adult survival occurred on almond and mixed pollens [88.0%-97. 6% after 1st feeding period (10 days), 78.0%-90.8% after 3rd feeding period (10 days), 55. 0%-83.6% after 5th feeding period (10 days), and 15.2%-32.4% after lOth feeding period (10 days)]. The lowest adult survival occurred on citrus pollen [52.0%-56.0% after 1st feeding period (10 days), 13.3% after 3rd and 5th feeding periods (10 days), and 0 after 6th feeding period (10 days)]. Pollen feeding is not a behavior restricted to adult boll weevils of a specific sex or physiological state. Understanding how boll weevil adults survive in the absence of cotton is important to ensure ultimate success of eradicating this pest in the subtropics. 相似文献
105.
Ulrich K. Steiner Adam Lenart Ming Ni Peipei Chen Xiaohu Song Franois Taddei James W. Vaupel Ariel B. Lindner 《Evolution; international journal of organic evolution》2019,73(4):847-857
Despite advances in aging research, a multitude of aging models, and empirical evidence for diverse senescence patterns, understanding of the biological processes that shape senescence is lacking. We show that senescence of an isogenic Escherichia coli bacterial population results from two stochastic processes. The first process is a random deterioration process within the cell, such as generated by random accumulation of damage. This primary process leads to an exponential increase in mortality early in life followed by a late age mortality plateau. The second process relates to the stochastic asymmetric transmission at cell fission of an unknown factor that influences mortality. This secondary process explains the difference between the classical mortality plateaus detected for young mothers’ offspring and the near nonsenescence of old mothers’ offspring as well as the lack of a mother–offspring correlation in age at death. We observed that lifespan is predominantly determined by underlying stochastic stage dynamics. Surprisingly, our findings support models developed for metazoans that base their arguments on stage‐specific actions of alleles to understand the evolution of senescence. We call for exploration of similar stochastic influences that shape aging patterns beyond simple organisms. 相似文献
106.
107.
Tobias Ruck Stefanie Bock Steffen Pfeuffer Christina B.Schroeter Derya Cengiz Paul Marciniak Maren Lindner Alexander Herrmann Marie Liebmann Stjepana Kovac Lukas Gola Leoni Rolfes Marc Pawlitzki Nils Opel Tim Hahn Udo Dannlowski Thomas Pap Felix Luessi Julian A.Schreiber Bernhard Wünsch Tanja Kuhlmann Guiscard Seebohm Bjrn Tackenberg Patricia Seja Frank Dring Erhard Wischmeyer Achmet Imam Chasan Johannes Roth Luisa Klotz Gerd Meyer zu Hrste Heinz Wiendl Tobias Marschall Stefan Floess Jochen Huehn Thomas Budde Tobias Bopp Stefan Bittner Sven G.Meuth 《Cell research》2022,32(1):72-88
It remains largely unclear how thymocytes translate relative differences in T cell receptor (TCR) signal strength into distinct developmental programs that driv... 相似文献
108.
Ant inquilines are obligate social parasites, usually lacking a sterile worker caste, which are dependent on their hosts for survival and reproduction. Social parasites are rare among the fungus‐gardening ants (Myrmicinae: tribe Attini) and only four species are known until now, all being inquilines from the Higher Attini. We describe Mycocepurus castrator sp.n. , the first inquiline social parasite to be discovered in the Lower Attini. Our study of the parasite's behaviour and life history supports the conclusion drawn from external morphology: Mycocepurus castrator is an evolutionarily derived inquiline parasite of Mycocepurus goeldii. Inquilines are of great interest to evolutionary biology because it is debated if they originated via sympatric or allopatric speciation. We discuss the life history evolution, behaviour and morphology of socially parasitic, fungus‐growing ants. 相似文献
109.
Regulation of interferon and retinoic acid-induced cell death activation through thioredoxin reductase 总被引:2,自引:0,他引:2
Ma X Karra S Guo W Lindner DJ Hu J Angell JE Hofmann ER Reddy SP Kalvakolanu DV 《The Journal of biological chemistry》2001,276(27):24843-24854
Interferons (IFNs) and retinoids are potent biological response modifiers. The IFN-beta and all-trans-retinoic acid combination, but not these single agents individually, induces death in several tumor cell lines. To elucidate the molecular basis for these actions, we have employed an antisense knockout approach to identify the gene products that mediate cell death and isolated several genes associated with retinoid-IFN-induced mortality (GRIMs). One of the GRIM cDNAs, GRIM-12, was identical to human thioredoxin reductase (TR). To define the functional relevance of TR to cell death and to define its mechanism of death-modulating functions, we generated mutants of TR and studied their influence on the IFN/RA-induced death regulatory functions of caspases. Wild-type TR activates cell death that was inhibited in the presence of caspase inhibitors or catalytically inactive caspases. A mutant TR, lacking the active site cysteines, inhibits the cell death induced by caspase 8. IFN/all-trans-retinoic acid-induced cytochrome c release from the mitochondrion was promoted in the presence of wild type and was inhibited in the presence of mutant TR. We find that TR modulates the activity of caspase 8 to promote death. This effect is in part caused by the stimulation of death receptor gene expression. These studies identify a new mechanism of cell death regulation by the IFN/all-trans-retinoic acid combination involving redox enzymes. 相似文献
110.