Isomer and glycomer complexities of core GlcNAcs in Caenorhabditis elegans

Analysis of protein glycosylation within the nematode Caenorhabditis elegans has revealed an abundant and unreported set of core chitobiose modifications (CCMs) to N-linked glycans. With hydrazine release, an array of glycomers and isobars were detected with hexose extensions on the 3- and 3,6-positions of the penultimate and reducing terminus, respectively. A full complement of structures includes a range of glycomers possessing a Galbeta(1-4)Fuc disaccharide at the 3- and 6-positions of the protein-linked GlcNAc. Importantly, enzymatic (PNGase F/A) release failed to liberate many of these extended structures from reduced and alkylated peptides and, as a consequence, such profiles were markedly deficient in a representation of the worm glycome. Moreover, the 3-linked Galbeta(1-4)Fuc moiety was notably resistant to a range of commercial galactosidases. For identification, the fragments were spectrum-matched with synthetic products and library standards using sequential mass spectrometry (MS(n)). A disaccharide observed at the 3-position of penultimate GlcNAc, indicating a Hex-Fuc branch on some structures, was not further characterized because of low ion abundance in MS(n). Additionally, a Hex-Hex-Fuc trisaccharide on the 6-position of proximal GlcNAc was also distinguished on select glycomers. Similar branch extensions on 6-linked core fucosyl residues have recently been reported among other invertebrates. Natural methylation and numerous isobars complement the glycome, which totals well over 100 individual structures. Complex glycans were detected at lower abundance, indicating glucosaminyltransferase-I (GnT-I) and GnT-II activity. A range of phosphorylcholine (PC)-substituted complex glycans were also confirmed following a signature two-stage loss of PC during MS(n) analysis, although the precursor ion was not observed in the mass profiles. In a similar manner, numerous other minor glycans may be present but unobserved in hydrazine-release profiles dominated by fucosylated structures. All CCM structures, including multiple isomers, were determined without chromatography by gas-phase disassembly (MS(n)) in Paul and linear ion trap (IT) instruments.     

Secondary structure and phylogenetic analysis of the internal transcribed spacers 1 and 2 of bush crickets (Orthoptera: Tettigoniidae: Barbitistini)

We inferred secondary structure models of the internal transcribed spacers (ITS) 1 and 2 of bush crickets using a combined comparative and thermodynamic approach. The inferred secondary structure models were used to account for interdependency of interacting nucleotides in a phylogenetic analysis of the bush cricket genus Poecilimon. Our analysis indicates that the two previously reported conformational structures (i.e., hairpin and ring) of ITS2 are likely to fold in bush crickets as well and that both predicted structures are similar to those proposed for other eukaryotes. Comparing predicted ITS1 secondary structure models proved to be difficult because of substantial variation in their nucleotide sequence length. Our study revealed that the phylogenetic signal of ITS1 and ITS2 is largely congruent with that preserved in the mitochondrial genes 16S rRNA, tRNA‐Val and 12S rRNA. The phylogenetic signal in both the nuclear and the mitochondrial genome question the monophyly of the genus Poecilimon: species of the genera Poecilimonella, Parapoecilimon, Polysarcus and Phonochorion consistently cluster within Poecilimon.     

IL-4 inhibits the TNF-α induced proliferation of renal cell carcinoma (RCC) and cooperates with TNF-α to induce apoptotic and cytokine responses by RCC: implications for antitumor immune responses

Objective: While previous reports clearly demonstrated antiproliferative effects of IL-4 on renal cell carcinoma (RCC) in vitro, the administration of IL-4 to patients with metastatic RCC in clinical trials could not recapitulate the promising preclinical results. In the present study we wanted to examine the context of IL-4 action and to establish conditions of enhanced IL-4 efficacy. Methods: Primary and permanent human RCC cells were cultured in either serum-supplemented or chemically defined, serum-free culture medium in the presence or absence of cytokines. Cell proliferation was assessed as [³H]-thymidine incorporation. Cell apoptosis was measured using the fluorescent DNA intercalator 7-aminoactinomycin D and flow cytometry. In addition, culture media conditioned by RCC were subjected to cytokine antibody array and cytokine multiplex analysis. Results: Our results indicate that the previously reported antiproliferative effects of IL-4 are serum-dependent. Under serum-free conditions, IL-4 failed to exhibit growth-inhibitory effects or was even growth-stimulatory. In a chemically defined, serum-free medium (AIM-V), however, IL-4 inhibited the TNF-α induced proliferation of RCC. IL-4 and TNF-α synergistically induced apoptosis of RCC as well as a complex cytokine response by RCC, which included the synergistic upregulation of RANTES and MCP-1. Conclusions: IL-4 alone has little effect on the spontaneous proliferation of RCC but can prevent the enhancement of proliferation induced by growth promoters like FBS and TNF-α. The concomitant growth inhibitory, apoptosis-inducing, and cytokine-enhancing effects of IL-4 in combination with TNF-α on RCC support the view that Th2 cytokines may be required for productive immune responses against RCC.     

Limitation of nocturnal ATP import into chloroplasts seems to affect hormonal crosstalk, prime defense, and enhance disease resistance in Arabidopsis thaliana

When grown under short-day conditions at low light, leaves of an Arabidopsis thaliana (accession Col-0) mutant with defects in the two genes encoding plastid ATP/ADP antiporters (so-called ntt1-2 null mutants) display a variety of physiological changes. These include the formation of necrotic lesions and the accumulation of hydrogen peroxide in the leaves. Here, we show that, under short-day conditions, leaves of the ntt1-2 mutant display enhanced resistance to Hyaloperonospora arabidopsidis, Botrytis cinerea, and Pseudomonas syringae pv. tomato DC3000. Resistance to these pathogens was associated with constitutively elevated levels of the plant hormone salicylic acid and, eventually, jasmonic acid, and constitutive or primed activation after pathogen attack of various defense genes that are dependent on these hormones. In addition, the antagonistic crosstalk between the salicylic acid and jasmonic acid signaling pathways seems to be affected in ntt1-2. Because the enhanced resistance of ntt1-2 to H. arabidopsidis was not seen when the mutant was grown under long-day conditions, our findings argue that nocturnal ATP import into chloroplasts is crucial to keep A. thaliana from runaway activation of pathogen resistance.     

Atresia of the dominant ovarian follicle in rhesus monkeys is detected within 24 hours of estradiol treatment

Following treatment with estradiol-17β (E₂) on day 6 of the menstrual cycle, degenerative alterations in the microenvironment of the dominant follicle (DF) (follicular fluid [FF], granulosa cells [GC], and oocyte) are readily apparent on day 10, or 96 h after E₂ administration. The present study was designed to determine how early such changes could be detected and which indices of atresia were observed first. The DF was identified during laparoscopy on day 5 or 6 of the cycle, and four capsules containing crystalline E₂ were inserted s.c. for 24 h. Contents of the DF were aspirated at 24, 48, and 72 h following initiation of E₂ treatment. General size and appearance of the DF did not change distinctly with E₂ treatment; however, by 48 h FF viscosity was increased markedly. GC viability was not altered with treatment. FF concentrations of estrogen (E) were dramatically reduced at 24 h. These differences were maintained at 48 h and at 72 h. E accumulation by cultured GC was significantly reduced by > eightfold. There appeared a similar trend for reduced progesterone (P) in FF and decreased P production by GC in vitro. These results demonstrate that degenerative alterations in the DF indicative of atresia can be detected as early as 24 h after initiation of E₂ treatment; the index of atresia appearing earliest is a reduction in FF concentrations of E, and the first morphological changes in the DF can be observed 24 h later. This study indicates that biochemical alterations precede morphologic changes with E₂-induced atresia, and should allow us to begin to determine the earliest events and putative initiation sites of atresia.     

A double fluorescence method for determining doxorubicin distribution and vascular supply in the mouse kidney

Freeze-sectioning followed by freeze-drying completely preserves the topographic distribution of soluble substances, with the additional advantage of permitting permanent mounting. This rapid and effective technique was applied to study the distribution of fluorescence of the cytotoxic drug Doxorubicin in microscopic slices from in vivo treated animals. A fluorescent conjugate of different fluorescence, Blankophor-G-Dextran, which remained in the vessels, was used in the same living animals to characterize the vascular supply in the kidney of treated mice in relation to Doxorubicin distribution.