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Characterization of regulatory (interferon-alpha/beta) and accessory (LAF/IL 1) monokine activities from liver granuloma macrophages of Schistosoma mansoni-infected mice.

Previously it was shown that macrophages (M phi) isolated from the vigorous (Vig) or modulated (Mod) liver granulomas (Gr) of Schistosoma mansoni-infected mice restored mitogen and parasite egg antigen-induced proliferative responses to accessory cell-depleted lymphocytes. Furthermore, supraoptimal concentrations of highly activated VigGrM phi suppressed lymphoproliferation to a greater extent than did the lesser activated ModGrM phi. In this study we investigated the role of soluble mediators in GrM phi accessory/regulatory activity. Indomethacin released VigGrM phi-mediated inhibition of mitogen but not antigen-induced lymphoproliferation. Extensively dialyzed serum-free GrM phi culture supernatant nonspecifically suppressed SEA- or KLH-induced blastogenesis. Culture supernatants also reduced vesicular stomatitis virus-induced plaque formation in supernatant-pretreated L-929 fibroblasts. The 20 to 45 Kd GrM phi-derived lymphoproliferation suppressive factor (SF) and the 20 to 50 Kd viral plaque-reducing factor (PRF) were stable at low pH, but became inactivated by heat and trypsin digestion. Although freshly isolated Vig or ModGrM phi contained preformed SF and PRF, in vitro production of the factors were depressed by protein synthesis inhibitors. Moreover, SF was active only when added to cultures before day 3 of the 6-day proliferation assay. Both SF and PRF were specifically retained on rabbit anti-murine IFN-alpha/beta immunoaffinity columns. Thus, the suppressive activity of Vig or ModGrM phi is in part mediated by a monokine that shares physical, biological, and antigenic characteristics with murine IFN-alpha/beta. In contrast to the suppression of antigen-driven proliferation, GrM phi culture supernatant costimulated PHA-induced mitogenesis. The 13 to 21 Kd GrM phi-derived lymphocyte-activating factor (LAF) was stable to heat, low pH, and trypsin digestion. Freshly isolated Vig or ModGrM phi contained preformed LAF, although its in vitro production was depressed by protein synthesis inhibitors. The physical and biological characteristics of GrM phi-derived LAF appear similar to IL 1. It is concluded that both Vig and ModGrM phi secrete regulatory/accessory monokines that may contribute to the initiation and maintenance of the focal inflammatory granulomatous response.

Animals↗

Methods for effective real-time RT-PCR analysis of virus-induced gene silencing.

We applied real-time RT-PCR to the analysis of Tobacco rattle virus (TRV)-mediated virus-induced gene silencing (VIGS) of the phytoene desaturase (PDS) gene in Nicotiana benthamiana and tomato. Using a combination of direct measurement and mathematical assessment, we evaluated three plant genes, ubiquitin (ubi3), elongation factor-1 alpha (EF-1), and actin, for use as internal reference transcripts and found that EF-1 and ubi3 were least variable under our experimental conditions. Primer sets designed to amplify the 5' or 3' regions of endogenous PDS transcripts in tomato yielded similar reductions in transcript levels indicating a uniform VIGS-mediated degradation of target RNA. By measuring the ratio of the abundance of the PDS insert transcript to the TRV coat protein RNA, we established that the PDS insert within TRV was stable in both hosts. VIGS in N. benthamiana resulted in complete photo-bleaching of all foliar tissue compared to chimeric bleaching in tomato. PDS transcript levels were decreased eleven- and seven-fold in photobleached leaves of N. benthamiana and tomato, respectively, while sampling tomato leaflets on the basis of age rather than visible bleaching resulted in only a 17% reduction in PDS coupled with a large leaf-to-leaf variation. There was a significant inverse relationship (r2=76%, P=0.01) between the relative abundance of CP RNA and the amount of PDS transcript in rTRV::tPDS-infected tomato suggesting that virus spread and accumulation are required precursors for successful VIGS in this host.

Gene Silencing↗

Use of geminiviral vectors for functional genomics.

Virus-induced gene silencing (VIGS) can be used to study the function of a gene by downregulating its expression and analyzing the resulting phenotype. VIGS is a handy tool that is less time consuming and labor intensive than other methods for generating mutants. Geminiviruses are particularly convenient and valuable choices as VIGS vectors in functional genomics. The small size of their DNA genome, the simplicity of the methods for inoculation, their wide host range and their conserved genome organization are just a few of the advantageous characteristics that this group of viruses has to offer. Geminivirus-based vectors have proved to be very efficient in VIGS systems, and further development of these systems will most probably permit their application in studies of the functional genomics of important crops that are recalcitrant to other forms of analysis.

Geminiviridae↗

Virus induced gene silencing of a DEFICIENS ortholog in Nicotiana benthamiana.

Traditionally, developmental studies in plant biology have suffered from the lack of a convenient means to study gene function in non-model plant species. Here we show that virus-induced gene silencing (VIGS) is an effective new tool to study the function of orthologs of floral homeotic genes such as DEFICIENS (DEF) in non-model systems. We used a tobacco rattle virus (TRV)-based VIGS approach to study the function of the Nicotiana benthamiana DEF ortholog (NbDEF). Silencing of NbDEF in N. benthamiana using TRV-VIGS was similar to that of Antirrhinum def and Arabidopsis ap3 mutants and caused transformation of petals into sepals and stamens into carpels. Molecular analysis of the NbDEF -silenced plants revealed a dramatic reduction of the levels of NbDEF mRNA and protein in flowers. NbDEF silencing was specific and has no effect on the mRNA levels of NbTM6, the closest paralog of NbDEF. A dramatic reduction of the levels of N. benthamiana GLOBOSA (NbGLO) mRNA and protein was also observed in flowers of NbDEF-silenced plants, suggesting that cross-regulation of this GLO-like gene by NbDEF. Taken together, our results suggest that NbDEF is a functional homolog of Antirrhinum DEF. Our results are significant in that they show that TRV efficiently induces gene silencing in young and differentiating flowers and that VIGS is a promising new tool for analyses of developmental gene function in non-model organisms.

DEFICIENS Protein↗

Tobacco Rar1, EDS1 and NPR1/NIM1 like genes are required for N-mediated resistance to tobacco mosaic virus.

The tobacco N gene confers resistance to tobacco mosaic virus (TMV) and encodes a Toll-interleukin-1 receptor/nucleotide binding site/leucine-rich repeat (TIR-NBS-LRR) class protein. We have developed and used a tobacco rattle virus (TRV) based virus induced gene silencing (VIGS) system to investigate the role of tobacco candidate genes in the N-mediated signalling pathway. To accomplish this we generated transgenic Nicotiana benthamiana containing the tobacco N gene. The transgenic lines exhibit hypersensitive response (HR) to TMV and restrict virus spread to the inoculated site. This demonstrates that the tobacco N gene can confer resistance to TMV in heterologous N. benthamiana. We have used this line to study the role of tobacco Rar1-, EDS1-, and NPR1/NIM1- like genes in N-mediated resistance to TMV using a TRV based VIGS approach. Our VIGS analysis suggests that these genes are required for N function. EDS1-like gene requirement for the N function suggests that EDS1 could be a common component of bacterial, fungal and viral resistance signalling mediated by the TIR-NBS-LRR class of resistance proteins. Requirement of Rar1- like gene for N-mediated resistance to TMV and some powdery mildew resistance genes in barley provide the first example of converging points in the disease resistance signalling pathways mediated by TIR-NBS-LRR and CC-NBS-LRR proteins. The TRV based VIGS approach as described here to study N-mediated resistance signalling will be useful for the analysis of not only disease resistance signalling pathways but also of other signalling pathways in genetically intractable plant systems.

Amino Acid Sequence↗

Depletion of UDP-D-apiose/UDP-D-xylose synthases results in rhamnogalacturonan-II deficiency, cell wall thickening, and cell death in higher plants.

D-apiose serves as the binding site for borate cross-linking of rhamnogalacturonan II (RG-II) in the plant cell wall, and biosynthesis of D-apiose involves UDP-D-apiose/UDP-D-xylose synthase catalyzing the conversion of UDP-D-glucuronate to a mixture of UDP-D-apiose and UDP-D-xylose. In this study we have analyzed the cellular effects of depletion of UDP-D-apiose/UDP-D-xylose synthases in plants by using virus-induced gene silencing (VIGS) of NbAXS1 in Nicotiana benthamiana. The recombinant NbAXS1 protein exhibited UDP-D-apiose/UDP-D-xylose synthase activity in vitro. The NbAXS1 gene was expressed in all major plant organs, and an NbAXS1-green fluorescent protein fusion protein was mostly localized in the cytosol. VIGS of NbAXS1 resulted in growth arrest and leaf yellowing. Microscopic studies of the leaf cells of the NbAXS1 VIGS lines revealed cell death symptoms including cell lysis and disintegration of cellular organelles and compartments. The cell death was accompanied by excessive formation of reactive oxygen species and by induction of various protease genes. Furthermore, abnormal wall structure of the affected cells was evident including excessive cell wall thickening and wall gaps. The mutant cell walls contained significantly reduced levels of D-apiose as well as 2-O-methyl-L-fucose and 2-O-methyl-D-xylose, which serve as markers for the RG-II side chains B and A, respectively. These results suggest that VIGS of NbAXS1 caused a severe deficiency in the major side chains of RG-II and that the growth defect and cell death was likely caused by structural alterations in RG-II due to a D-apiose deficiency.

Carbon-Nitrogen Ligases↗

Efficient virus-induced gene silencing in roots using a modified tobacco rattle virus vector.

Due to their capability of eliciting a form of posttranscriptional gene silencing (termed virus-induced gene silencing or VIGS), plant viruses are increasingly used as reverse-genetics tools for functional characterization of plant genes. RNA viruses have been shown to trigger silencing in a variety of host plants, including members of Solanacae and Arabidopsis (Arabidopsis thaliana). Several factors affect the silencing response, including host range and viral tropism within the plant. The work presented here demonstrates that a modified tobacco rattle virus (TRV) vector retaining the helper protein 2b, required for transmission by a specific vector nematode, not only invades and replicates extensively in whole plants, including meristems, but also triggers a pervasive systemic VIGS response in the roots of Nicotiana benthamiana, Arabidopsis, and tomato (Lycopersicon esculentum). This sustained VIGS response was exemplified by the silencing of genes involved in root development (IRT1, TTG1 [transparent testa glabra], RHL1 [root hairless1], and beta-tubulin), lateral root-meristem function (RML1 [root meristemless1]), and nematode resistance (Mi). Roots of silenced plants exhibit reduced levels of target mRNA and phenocopy previously described mutant alleles. The TRV-2b vector displays increased infectivity and meristem invasion, both key requirements for efficient VIGS-based functional characterization of genes in root tissues. Our data suggest that the TRV helper protein 2b may have an essential role in the host regulatory mechanisms that control TRV invasion.

Animals↗

Virus-induced gene silencing-based functional characterization of genes associated with powdery mildew resistance in barley.

We successfully implemented virus-induced gene silencing (VIGS) in barley (Hordeum vulgare) for the functional characterization of genes required for Mla13-mediated resistance toward the biotrophic barley pathogen Blumeria graminis f. sp. hordei. Initially, barley cultivars were screened for their ability to host the barley stripe mosaic virus (BSMV)-VIGS vector by allowing its replication and systemic movement without causing excessive symptoms. Phytoene desaturase silencing leading to photobleaching was used as a phenotypic marker alongside reverse transcription-PCR data to characterize the silencing response at the molecular level. Barley cultivar Clansman, harboring the Mla13 resistance gene, was chosen as the most suitable host for BSMV-VIGS-based functional characterization of Rar1, Sgt1, and Hsp90 in the Mla-mediated resistance toward powdery mildew. BSMV-induced gene silencing of these candidate genes, which are associated in many but not all race-specific pathways, proved to be robust and could be detected at both mRNA and protein levels for up to 21 d postinoculation. Systemic silencing was observed not only in the newly developed leaves from the main stem but also in axillary shoots. By examining fungal development from an incompatible mildew strain carrying the cognate Avr13 gene on plants BSMV silenced for Rar1, Sgt1, and Hsp90, a resistance-breaking phenotype was observed, while plants infected with BSMV control constructs remained resistant. We demonstrate that Hsp90 is a required component for Mla13-mediated race-specific resistance and that BSMV-induced VIGS is a powerful tool to characterize genes involved in pathogen resistance in barley.

Carrier Proteins↗

Nicotiana benthamiana gp91phox homologs NbrbohA and NbrbohB participate in H2O2 accumulation and resistance to Phytophthora infestans.

Active oxygen species (AOS) are responsible for triggering defense responses in plants. Respiratory burst oxidase homologs (rboh genes) have been implicated in AOS generation. We have isolated two rboh cDNAs, NbrbohA and NbrbohB, from Nicotiana benthamiana leaves. NbrbohA was expressed constitutively at a low level and the transcripts were increased after mechanical stress of control leaf infiltration, whereas NbrbohB was induced specifically by the protein elicitor INF1 from the potato pathogen Phytophthora infestans. We examined the function of the Nbrboh genes in AOS generation and in the hypersensitive response (HR) using virus-induced gene silencing (VIGS). VIGS indicated that both genes are required for H2O2 accumulation and for resistance to Phytophthora. VIGS of Nbrboh genes also led to a reduction and delay of HR cell death caused by INF1. We further demonstrate that the induction of HR-like cell death by overexpression of a constitutively active mutant of a mitogen-activated protein kinase kinase, MEK(DD), is compromised by VIGS of NBRBOHB: We found that MEK(DD) induced NbrbohB but not NBRBOHA: This work provides genetic evidence for the involvement of a mitogen-activated protein kinase cascade in the regulation of rboh genes.

Acetates↗

Virus-induced gene silencing in Solanum species.

Virus-induced gene silencing (VIGS) has been used routinely in Nicotiana benthamiana to assess functions of candidate genes and as a way to discover new genes required for diverse pathways, especially disease resistance signalling. VIGS has recently been shown to work in Arabidopsis thaliana and in tomato. Here, we report that VIGS using the tobacco rattle virus (TRV) viral vector can be used in several Solanum species, although the choice of vector and experimental conditions vary depending on the species under study. We have successfully silenced the phytoene desaturase (PDS) gene in the diploid wild species Solanum bulbocastanum and S. okadae, in the cultivated tetraploid S. tuberosum and in the distant hexaploid relative S. nigrum (commonly known as deadly nightshade). To test whether the system could be utilised as a rapid way to assess gene function of candidate resistance (R) genes in potato and its wild relatives, we silenced R1 and Rx in S. tuberosum and RB in S. bulbocastanum. Silencing of R1, Rx and RB successfully attenuated R-gene-mediated disease resistance and resulted in susceptible phenotypes in detached leaf assays. Thus, the VIGS system is an effective method of rapidly assessing gene function in potato.

Gene Silencing↗

Phase II trial of vinblastine, ifosfamide, and gallium combination chemotherapy in metastatic urothelial carcinoma.

PURPOSE: Phase II trial in metastatic urothelial carcinoma using a novel combination chemotherapy regimen consisting of vinblastine, ifosfamide, and gallium nitrate (VIG). PATIENTS AND METHODS: Twenty-seven patients were entered onto this phase II study. Dosages were vinblastine 0.11 mg/kg days 1 and 2, ifosfamide 1.2 gm/m2 days 1 through 5 (with mesna), and gallium 300 mg/m2 as a 24-hour infusion days 1 through 5, with calcitriol (1,25-dihydroxycholecalciferol) 0.5 microgram/d orally starting 3 days before each course (except the first) and continuing throughout gallium administration, plus recombinant human granulocyte colony-stimulating factor (rhG-CSF) (filgrastim) 5 micrograms/kg/d days 7 through 16. Courses were repeated every 21 days for a maximum of six cycles. RESULTS: The major toxicity was granulocytopenia. Fifteen patients (55.6%) had grade 3 or 4 granulocytopenia, including eight patients with granulocytopenic fevers. Eleven patients had grade 3 or 4 anemia and four had grade 3 or 4 nephrotoxicity, which was reversible. Other grade 3 to 4 toxicities included hypocalcemia (three patients), thrombocytopenia (two), encephalopathy (one), and temporary blindness (one). There was one treatment-related mortality. Toxicity was more severe in patients older than 70 years and those with prior pelvic irradiation, prior cisplatin adjuvant therapy, or prior nephrectomy. We now decrease VIG by 20% in this patient population. Eighteen patients (67%) achieved an objective response, including 11 (41%) who attained a disease-free status (five with VIG alone and six with subsequent surgery). Median duration of remission was 20 weeks, with five patients still in remission at 22+ to 56+ weeks. CONCLUSION: VIG combination chemotherapy is very active in patients with metastatic urothelial carcinoma. Toxicity was significant but manageable.

Adult↗

Vertical isolated gastroplasty with gastro-enteral bypass: preliminary results.

BACKGROUND: The authors present a new restrictive and malabsorptive operation for treatment of morbid obesity, called vertical isolated gastroplasty (VIG). METHODS: From Feb 2004 to May 2005, 30 patients with BMI > or = 40 kg/m2 or >35 kg/m2 with co-morbidities underwent VIG via laparoscopy or laparotomy. The technique consisted in creation of a gastric tube preserving pylorus, and a Roux-limb of 300 cm to the bypassed stomach with the division 30 cm distal to the ligament of Treitz. Excess weight loss (EWL), BMI, complications and co-morbidities were assessed. RESULTS: BMI and average preoperative weight were 41.2 kg/m2 and 110.7 kg, respectively. At 12 months postoperatively, BMI and average weight were 23.4 kg/m2 and 65.1 kg, respectively, with EWL 90.2%. None of the patients presented dumping. Improvement in co-morbidities was >90%. Complications consisted of: 1 dehiscence of gastric sutureline, 1 hemoperitoneum, 1 gastroenterostomy ulcer, 1 anemia of undetermined cause, and 3 cholelithiasis. There was no mortality. CONCLUSION: VIG has thus far been safe and effective, with the same results as other bariatric operations. VIG has certain advantages, such as lack of dumping and lack of clinically significant stenosis of the gastroenterostomy, which can occur with other techniques. Because a duodenal bypass is not performed, it allows physiologic absorption of iron and diagnostic and/or therapeutic access to the ampulla of Vater.

Adult↗

Virus-induced gene silencing.

In the postgenomic era, large-scale functional genomic approaches are necessary for converting sequence information into functional information. A para-genetic approach, called virus-induced gene silencing (VIGS), offers a rapid means of gaining insight into gene function in plants. VIGS system could be used to suppress endogenous gene expression by infecting plants with a recombinant virus vector (VIGS vector) carrying host-derived sequence. Here, we describe the use of tobacco rattle virus (TRV)-based VIGS technique to study gene function in Nicotiana benthamiana and tomato.

Gene Silencing↗

Analysis of gene function in rice through virus-induced gene silencing.

Virus-induced gene silencing (VIGS) is a powerful RNA-silencing based technology adapted for the study of host-gene function. VIGS functions through the expression of a host gene from a virus vector. Both the virus-encoded host sequence and the homologous host target messenger RNA are destroyed or made inactive through a host surveillance system. Here, we describe procedures for the use of a new virus vector for VIGS in monocotyledonous hosts and, in particular, in rice (Oryza sativa), a species for which no VIGS vector was previously available.

Bromovirus↗

Virus-induced gene silencing as a tool for functional genomics in weeds: Challenges and future directions.

Virus-induced gene silencing (VIGS) has evolved from a conceptual demonstration of antiviral defense into a pivotal reverse-genetics platform for plant functional genomics. By exploiting engineered DNA- or RNA-based viral vectors, VIGS enables rapid, sequence-specific transcript knockdown through RNA-mediated degradation of target transcripts. Recent refinements in vector design, inoculation strategies, and viral species selection, such as TRV, BSMV, and FoMV, have expanded its application to previously recalcitrant plants, including major crops and emerging weed models. In weeds, functional genomics remains particularly challenging due to high genetic variability, limited genomic resources, and incompatibility with conventional viral vectors and transformation systems. In this context, VIGS provides a tractable approach to investigate genes associated with herbicide resistance, metabolic adaptation, and stress tolerance. Beyond weed biology, its application to studies of immune signaling, hormonal crosstalk, and secondary metabolism highlights VIGS as a versatile biotechnology for elucidating gene function and supporting next-generation strategies in plant improvement and integrated pest management.

Journal Article↗

Smallpox vaccination reactions, prophylaxis, and therapy of complications.

Smallpox vaccination in the United States is a routine public health measure which has been under intensive review during the last decade. The most frequently occurring adverse reactions to vaccination are benign and require little or no systemic therapy. These reactions include accidental infection, erythematous and urticarial rash, and generalized vaccinia. Chickenpox occurring concurrently with vaccination presents no problem unless vaccinia has widely superinfected the chickenpox lesions. There is no risk to the pregnant woman who is vaccinated, but there is a slight risk that the fetus will develop fetal vaccinia. The vaccinia does not cause congenital malformations. Vaccinia hyperimmune globulin (VIG) in prophylactic dosage may be given to a pregnant woman who is traveling to a smallpox infected or endemic area in order to prevent fetal vaccinia. Vaccinia necrosum and eczema vaccinatum require vigorous systemic therapy with VIG, and often thiosemicarbazone. Post-vaccinial encephalitis, while frequently serious, has not been shown to be ameliorated by VIG therapy, although there are data which suggest VIG has some value in prophylaxis for encephalitis. Prophylaxis, prompt recognition, and proper therapy may reduce the fatality rates of these complications. Revaccination of patients who have suffered a complication is a frequent clinical problem. Revaccination of an individual who has had post-vaccinial encephalitis or vaccinia necrosum is contraindicated unless the risk of contracting smallpox outweighs the risk of the above two diseases. Revaccination of children who have had eczema vaccinatum is not contraindicated. Revaccination of children with a history of accidental infection or erythematous or urticarial rash presents no known or theoretically increased risk.

Eczema↗

Relations between psychometric profiles and cardiovascular autonomic regulation in physical education students.

This study was designed to investigate physical education (PE) students the link between mood disturbances, caused by psychological or physical stressors associated with studying, and the autonomic nervous system modifications. PE students completed the profile of mood state (POMS) questionnaire at the end of the university year. Heart rate variability (HRV) was then measured during a head-up tilt test (HUT) in those with the highest and lowest total mood disturbance (TMD) scores on three successive POMS. Among the 218 students who completed the POMS (85 female and 137 male), 65 had high TMD scores, suggesting mood disturbances and fatigue. The final sample included 12 subjects in the potentially overtrained (POT) group and 16 subjects in the control (CTL) group. A greater decrease of two indices of the autonomic system (SD1 and RMSSD) was observed during the HUT in the POT than in the CTL group (P < 0.05). The depression (Dep) and vigor (Vig) subscales of POMS were correlated with several HRV indices. More specifically, in the POT group, the Vig score was correlated with autonomous activity in the supine position, and the Dep score with percentages of change of sympatho-vagal activity during the HUT. This suggests that (1) POT students could present a weaker autonomic response to HUT, (2) Dep and Vig subscales of the POMS questionnaire may indicate autonomic dysregulations.

Adult↗

Functional characterization of Nicotiana benthamiana homologs of peanut water deficit-induced genes by virus-induced gene silencing.

Determining the functional role of genes that are differentially regulated during a stress response is challenging. In this study, few water deficit-induced genes from peanut were characterized in Nicotiana benthamiana using virus-induced gene silencing (VIGS) and their relevance for stress adaptation was validated. Twenty-five cDNA clones from peanut water deficit stress-induced cDNA library that had more than 50% nucleotide similarity with N. benthamiana or tomato homologs were selected. VIGS in peanut is not yet feasible and therefore we characterized these 25 genes in N. benthamiana. Increased membrane damage was seen under water deficit stress in most of the silenced plants signifying that many of these stress-induced genes are important to confer drought tolerance. Among the genes tested, silencing by homolog of flavonol 3-O-glucosyltransferase (F3OGT), homolog of alcohol dehydrogenase, homologous to salt inducible protein, and homolog of heat shock protein 70 showed more visible wilting symptoms compared with the control plants during water deficit stress. Interestingly, down-regulation of two genes, homologous to aspartic proteinase 2, and homolog of Jumonji class of transcription factor showed relative drought tolerant phenotypes. F3OGT silenced plants showed more wilting symptoms, membrane damage and chlorophyll degradation than any other silenced plants during water deficit. Our results demonstrate that VIGS approach can be used to characterize and assess the functional relevance of water deficit stress-induced cDNAs in a heterologous species.

Anthocyanins↗