Developmental Expression of Secretory β-1,4-endoglucanases in the Subventral Esophageal Glands of Heterodera glycines

Two β-1,4-endoglucanases (EGases), Hg-eng-1 and Hg-eng-2, were recently cloned from the soybean cyst nematode, Heterodera glycines, and their expression was shown in the subventral esophageal glands of hatched second-stage juveniles (J2). We examined the expression of these EGases in the subventral glands of all post-embryonic life stages of H. glycines by in situ hybridization and immunolocalization. The first detectable accumulation of EGase mRNAs occurred in the subventral glands of unhatched J2. EGase transcripts remained detectable in J2 after hatching and during subsequent root invasion. However, in late parasitic J2 and third-stage juveniles (J3), the percentage of individuals that showed EGase transcripts decreased. In female fourth-stage juveniles and adult females, EGase transcripts were no longer detected in the subventral glands. EGase hybridization signal reappeared in unhatched males coiled within the J3 cuticle, and transcripts were also present in the subventral glands of migratory adult males. Immunofluorescence labeling showed that EGase translation products are most abundantly present in the subventral glands of preparasitic J2, migratory parasitic J2, and adult males. The presence of EGases predominantly in the migratory stages suggests that the enzymes are used by the nematodes to soften the walls of root cells during penetration and intracellular migration

A parasitism gene from a plant-parasitic nematode with function similar to CLAVATA3/ESR (CLE) of Arabidopsis thaliana

The Hg-SYV46 parasitism gene is expressed exclusively in the dorsal oesophageal gland cell of parasitic stages of the soybean cyst nematode, Heterodera glycines, and it encodes a secretory protein that contains a C-terminal motif of the CLAVATA3/ESR-related (CLE) family in Arabidopsis thaliana. In shoot and floral meristems of Arabidopsis, the stem cells secret CLV3, a founding member of the CLE protein family, that activates the CLV1/CLV2 receptor complex and negatively regulates WUSCHEL expression to restrict the size of the stem cell population. Mis-expression of Hg-SYV46 in Arabidopsis (ecotype Columbia-0) under control of the CaMV35S promoter resulted in a wus-like phenotype including premature termination of the shoot apical meristem and the development of flowers lacking the central gynoecium. The wus-like phenotype observed was similar to reports of over-expression of CLV3 and CLE40 in Arabidopsis, as was down-regulation of WUS expression in the shoot apices of 35S::Hg-SYV46/Col-0 plants. Expression of 35S::Hg-SYV46 in a clv3-1 mutant of Arabidopsis was able partially or fully to rescue the mutant phenotype, probably dependent upon localization and level of transgene expression. A short root phenotype, as reported for over-expression of CLV3, CLE40 and CLE19 in roots, was also produced in primary 35S::Hg-SYV46/Col-0 transgenic plants. The results suggest a functional similarity of HG-SYV46 to plant-secreted CLE ligands that may play a role in the differentiation or division of feeding cells induced in plant roots by parasitic nematodes

Quantitative Detection of Double-Stranded RNA-Mediated Gene Silencing of Parasitism Genes in Heterodera glycines

The introduction of a double-stranded RNA (dsRNA) into an organism to induce sequence-specific RNA interference (RNAi) of a target transcript has become a powerful technique to investigate gene function in nematodes and many organisms. Data provided here indicate that the inclusion of 1–2 mM spermidine and 50 mM octopamine and a 24 hr incubation period of nematodes in double-stranded RNA (dsRNA) soaking solutions resulted in a considerable increase in the percentage of nematodes that ingested dsRNA as compared to previous reports. This modified dsRNA soaking method was coupled with quantitative real-time RT-PCR (qRT-PCR) analyses to assess the potential silencing of the Heterodera glycines parasitism gene transcripts Hg-pel-1 and Hg-4E02 that are expressed within the esophageal gland cells of preparasitic H. glycines J2. The Hg-pel-1 transcript was most efficiently silenced with one dsRNA construct (ds267) at the highest dsRNA soaking concentration of 5.0 mg/ml, while the Hg-4E02 transcript was more efficiently silenced at the 2.5 mg/ml dsRNA concentration as compared to 5.0 mg/ml. A dsRNA construct (ds285) complementary to a different sequence within the Hg-pel-1 transcript than construct ds267 induced only minimal silencing of the Hg-pel-1 transcript at 2.5 mg/ml. The results suggest that both dsRNA concentration and sequence relative to the transcript targeted are critical for maximizing potential RNAi effects in parasitic nematodes

Signal Peptide-Selection of cDNA Cloned Directly from the Esophageal Gland Cells of the Soybean Cyst Nematode Heterodera glycines

Secretions from the esophageal gland cells of plantparasitic nematodes play critical roles in the nematodeparasitic cycle. A novel method to isolate cDNA encoding putative nematode secretory proteins was developed that utilizes mRNA for reverse transcription-polymerase chain reaction derived from microaspiration of the esophageal gland cell contents of parasitic stages of the soybean cyst nematode Heterodera glycines. The resulting H. glycines gland cell cDNA was cloned into the pRK18 vector, and plasmid DNA was transformed into a mutated yeast host for specific selection of cDNA inserts that encode proteins with functional signal peptides. Of the 223 cDNA clones recovered from selection in yeast, 97% of the clones encoded a predicted signal peptide. Fourteen unique cDNA clones hybridized to genomic DNA of H. glycines on Southern blots and, among them, nine cDNA clones encoded putative extracellular proteins, as predicted by PSORT II computer analysis. Four cDNA clones hybridized to transcripts within the dorsal esophageal gland cell of parasitic stages of H. glycines, and in situ hybridization within H. glycines was not detected for eight cDNA clones. The protocol provides a direct means to isolate potential plant-parasitic nematode esophageal gland secretory protein genes

Effectiveness of Interventions to Reduce Contact Rates during a Simulated Influenza Pandemic

Measures to decrease contact between persons during an influenza pandemic have been included in pandemic response plans. We used stochastic simulation models to explore the effects of school closings, voluntary confinements of ill persons and their household contacts, and reductions in contacts among long-term care facility (LTCF) residents on pandemic-related illness and deaths. Our findings suggest that school closings would not have a substantial effect on pandemic-related outcomes in the absence of measures to reduce out-of-school contacts. However, if persons with influenzalike symptoms and their household contacts were encouraged to stay home, then rates of illness and death might be reduced by ≈50%. By preventing ill LTCF residents from making contact with other residents, illness and deaths in this vulnerable population might be reduced by ≈60%. Restricting the activities of infected persons early in a pandemic could decrease negative health impact

Compensatory guaiacyl lignin biosynthesis at the expense of syringyl lignin in 4CL1-knockout poplar

The lignin biosynthetic pathway is highly conserved in angiosperms, yet pathway manipulations give rise to a variety of taxon-specific outcomes. Knockout of lignin-associated 4-coumarate:CoA ligases (4CLs) in herbaceous species mainly reduces guaiacyl (G) lignin and enhances cell wall saccharification. Here we show that CRISPR-knockout of 4CL1 in poplar (Populus tremula x alba) preferentially reduced syringyl (S) lignin, with negligible effects on biomass recalcitrance. Concordant with reduced S-lignin was downregulation of ferulate 5-hydroxylases (F5Hs). Lignification was largely sustained by 4CL5, a low-affinity paralog of 4CL1 typically with only minor xylem expression or activity. Levels of caffeate, the preferred substrate of 4CL5, increased in line with significant upregulation of caffeoyl shikimate esterase1. Upregulation of caffeoyl-CoA O-methyltransferase1 and downregulation of F5Hs are consistent with preferential funneling of 4CL5 products toward G-lignin biosynthesis at the expense of S-lignin. Thus, transcriptional and metabolic adaptations to 4CL1-knockout appear to have enabled 4CL5 catalysis at a level sufficient to sustain lignification. Finally, genes involved in sulfur assimilation, the glutathione-ascorbate cycle, and various antioxidant systems were upregulated in the mutants, suggesting cascading responses to perturbed thioesterification in lignin biosynthesis

Phytonematode Peptide Effectors Exploit a Host Post‐Translational Trafficking Mechanism to the ER using a Novel Translocation Signal

Summary Cyst nematodes induce a multicellular feeding site within roots called a syncytium. It remains unknown how root cells are primed for incorporation into the developing syncytium. Furthermore, it is an enigma how CLAVATA3/ESR (CLE) peptide effectors secreted into the cytoplasm of the initial feeding cell could have an effect on plant cells so distant from where the nematode is feeding as the syncytium expands. Here we describe a novel translocation signal within nematode CLE effectors that is recognized by plant cell secretory machinery to redirect these peptides from the cytoplasm to the apoplast of plant cells. We show that the translocation signal is functionally conserved across CLE effectors identified in nematode species spanning three genera and multiple plant species, operative across plant cell types, and can traffic other unrelated small peptides from the cytoplasm to the apoplast of host cells via a previously unknown post‐translational mechanism of ER translocation. Our results uncover an unprecedented mechanism of effector trafficking by any plant pathogen to date and illustrates how phytonematodes can deliver effector proteins into host cells and then hijack plant cellular processes for their export back out of the cell to function as external signaling molecules to distant cells

Aβ Vaccination in Combination with Behavioral Enrichment in Aged Beagles: Effects on Cognition, Aβ, and Microhemorrhages

Beta-amyloid (Aβ) immunotherapy is a promising intervention to slow Alzheimer’s disease (AD). Aging dogs naturally accumulate Aβ and show cognitive decline. An active vaccine against fibrillar Aβ 1–42 (VAC) in aged beagles resulted in maintenance but not improvement of cognition along with reduced brain Aβ. Behavioral enrichment (ENR) led to cognitive benefits but no reduction in Aβ. We hypothesized cognitive outcomes could be improved by combining VAC with ENR in aged dogs. Aged dogs (11–12 years) were placed into 4 groups: (1) control/control (C/C); (2) control/VAC (C/V); (3) ENR/control (E/C); (4) ENR and VAC (E/V) and treated for 20 months. VAC decreased brain Aβ, pyroglutamate Aβ, increased CSF Aβ42 and BDNF RNA levels but also increased microhemorrhages. ENR reduced brain Aβ and prevented microhemorrhages. The combination treatment resulted in a significant maintenance of learning over time, reduced Aβ and increased BDNF mRNA despite increased microhemorrhages, however there were no benefits to memory. These results suggest that the combination of immunotherapy with behavioral enrichment leads to cognitive maintenance associated with reduced neuropathology that may benefit people with AD

Illness in Long-Term Travelers Visiting GeoSentinel Clinics

Length of travel appears to be associated with health risks

Generación de un anticorrosivo derivado de la extracción de las colillas de cigarrillo como alternativa para mejorar la resistencia a la corrosión en las estructuras metálicas

Trabajo de investigaciónLa presente investigación se plantea el desarrollo de un recubrimiento anticorrosivo a partir de las colillas de cigarrillo como principal fuente de preparación que garantice protección y funcionalidad en el acero que se implementa en la industria de la ingeniería civil, lo cual brindara una solución al manejo de los grandes problemas que estas implican en el medio ambiente, y de este modo optar por una nueva alternativa de anticorrosión.1. INTRODUCCIÓN 2. PLANTEAMIENTO Y FORMULACIÓN DEL PROBLEMA 3. METODOLOGÍA 4. ANÁLISIS DE RESULTADOS 5. CONCLUSIONES 6. RECOMENDACIÓNES ANEXOSPregradoIngeniero Civi