Unveiling the Diversity: Plant Parasitic Nematode Effectors and Their Plant Interaction Partners

Root-knot and cyst nematodes are two groups of plant parasitic nematodes that cause the majority of crop losses in agriculture. As a result, these nematodes are the focus of most nematode effector research. Root-knot and cyst nematode effectors are defined as secreted molecules, typically proteins, with crucial roles in nematode parasitism. There are likely hundreds of secreted effector molecules exuded through the nematode stylet into the plant. The current research has shown that nematode effectors can target a variety of host proteins and have impacts that include the suppression of plant immune responses and the manipulation of host hormone signaling. The discovery of effectors that localize to the nucleus indicates that the nematodes can directly modulate host gene expression for cellular reprogramming during feeding site formation. In addition, plant peptide mimicry by some nematode effectors highlights the sophisticated strategies the nematodes employ to manipulate host processes. Here we describe research on the interactions between nematode effectors and host proteins that will provide insights into the molecular mechanisms underpinning plant-nematode interactions. By identifying the host proteins and pathways that are targeted by root-knot and cyst nematode effectors, scientists can gain a better understanding of how nematodes establish feeding sites and subvert plant immune responses. Such information will be invaluable for future engineering of nematode-resistant crops, ultimately fostering advancements in agricultural practices and crop protection. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Calcium/calmodulin-mediated microbial symbiotic interactions in plants

Cytoplasmic calcium (Ca²⁺) transients and nuclear Ca²⁺ oscillations act as hubs during root nodulation and arbuscular mycorrhizal symbioses. Plants perceive bacterial Nod factors or fungal signals to induce the Ca²⁺ oscillation in the nucleus of root hair cells, and subsequently activate calmodulin (CaM) and Ca²⁺/CaM-dependent protein kinase (CCaMK). Ca²⁺ and CaM-bound CCaMK phosphorylate transcription factors then initiate down-stream signaling events. In addition, distinct Ca²⁺ signatures are activated at different symbiotic stages: microbial colonization and infection; nodule formation; and mycorrhizal development. Ca²⁺ acts as a key signal that regulates a complex interplay of downstream responses in many biological processes. This short review focuses on advances in Ca²⁺ signaling-regulated symbiotic events. It is meant to be an introduction to readers in and outside the field of bacterial and fungal symbioses. We summarize the molecular mechanisms underlying Ca²⁺/CaM-mediated signaling in fine-tuning both local and systemic symbiotic events.

Rooting Out the Mechanisms of Root-Knot Nematode-Plant Interactions

Root-knot nematodes (RKNs; Meloidogyne spp.) engage in complex parasitic interactions with many different host plants around the world, initiating elaborate feeding sites and disrupting host root architecture. Although RKNs have been the focus of research for many decades, new molecular tools have provided useful insights into the biological mechanisms these pests use to infect and manipulate their hosts. From identifying host defense mechanisms underlying resistance to RKNs to characterizing nematode effectors that alter host cellular functions, the past decade of research has significantly expanded our understanding of RKN-plant interactions, and the increasing number of quality parasite and host genomes promises to enhance future research efforts into RKNs. In this review, we have highlighted recent discoveries, summarized the current understanding within the field, and provided links to new and useful resources for researchers. Our goal is to offer insights and tools to support the study of molecular RKN-plant interactions.

Transcriptome Analyses of Pre-parasitic and Parasitic Meloidogyne Chitwoodi Race 1 to Identify Putative Effector Genes

Meloidogyne chitwoodi is a root-knot nematode that is a major pest of potato in the northwestern United States. Due to the lack of resistance against root-knot nematodes in potato, research has been undertaken to understand the M. chitwoodi-potato interaction at the molecular level. To identify the nematode genes that are playing roles in parasitism, we have performed transcriptome analyses on pre-parasitic and parasitic M. chitwoodi juveniles in susceptible potato. We compared gene expression profiles and identified genes that were significantly up- or down-regulated during nematode parasitism. Because parasitism proteins are typically secreted by the nematode to facilitate infection of host roots, we focused on the genes that encoded proteins that were predicted to be secreted. We found that approximately 34% (43/127) of the genes in the predicted secretome encoded proteins with no significant homology in the public genome databases, and 12% (15/127) encoded either a known effector, putative effectors or putative esophageal gland cell proteins. The transcriptome analyses of M. chitwoodi at the pre-parasitic and parasitic life stages shed light on the genes involved in nematode parasitism.

Nematode Genome Announcement: Draft Genome of Meloidogyne chitwoodi, an Economically Important Pest of Potato in the Pacific Northwest

Meloidogyne chitwoodi is one of the most devastating pests of potato in the U.S. Pacific Northwest (PNW). Nematode-infected tubers develop external as well as internal defects, making the potato tubers unmarketable, and resulting in economic losses. Draft genome assemblies of three M. chitwoodi genotypes-race 1, race 2 and race 1 pathotype Roza-were generated using Illumina and PacBio Sequel RS II sequencing. The final assemblies consist of 30, 39, and 38 polished contigs for race 1, race 2 and race 1 pathotype Roza, respectively, with average N₅₀ of 2.37 Mb and average assembled genome size of approximately 47.41 Mb. On average, 10,508 genes were annotated for each genome. Benchmarking universal single-copy ortholog (BUSCO) analysis indicated that 69.80% of the BUSCOs were complete whereas 68.80, 0.93, and 12.67% were single copy, duplicated, and fragmented, respectively. These highly contiguous genomes will enrich resources to study potato-nematode interactions and enhance breeding efforts to develop nematode-resistant potato varieties for the PNW.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Enhancing potato resistance against root-knot nematodes using a plant-defence elicitor delivered by bacteria

The root-knot nematode Meloidogyne chitwoodi is a pest that affects potato production in the Pacific Northwest of the United States. Here, to develop new strategies against M. chitwoodi infection of potato, we engineered Bacillus subtilis to secrete the plant-defence elicitor peptide StPep1. Pre-treatment of potato roots with the bacteria secreting StPep1 substantially reduced root galling, indicating that a bacterial secretion of a plant elicitor is an effective strategy for plant protection.

Transcriptome profiling of resistance response to Meloidogyne chitwoodi introgressed from wild species Solanum bulbocastanum into cultivated potato

BACKGROUND

Meloidogyne chitwoodi commonly known as Columbia root-knot nematode or CRKN is one of the most devastating pests of potato in the Pacific Northwest of the United States of America. In addition to the roots, it infects potato tubers causing internal as well as external defects, thereby reducing the market value of the crop. Commercial potato varieties with CRKN resistance are currently unavailable. Race specific resistance to CRKN has been introgressed from the wild, diploid potato species Solanum bulbocastanum into the tetraploid advanced selection PA99N82-4 but there is limited knowledge about the nature of its resistance mechanism. In the present study, we performed histological and differential gene expression profiling to understand the mode of action of introgressed CRKN resistance in PA99N82-4 in comparison to the CRKN susceptible variety Russet Burbank.

RESULTS

Histological studies revealed that the nematode juveniles successfully infect both resistant and susceptible root tissue by 48 h post inoculation, but the host resistance response restricts nematode feeding site formation in PA99N82-4. Differential gene expression analysis shows that 1268, 1261, 1102 and 2753 genes were up-regulated in PA99N82-4 at 48 h, 7 days, 14 days and 21 days post inoculation respectively, of which 61 genes were common across all the time points. These genes mapped to plant-pathogen interaction, plant hormonal signaling, antioxidant activity and cell wall re-enforcement pathways annotated for potato.

CONCLUSION

The introgressed nematode resistance in PA99N82-4 is in the form of both pattern-triggered immune response and effector-triggered immune response, which is mediated by accumulation of reactive oxygen species and hypersensitive response (HR). Salicylic acid is playing a major role in the HR. Polyamines and suberin (a component of the Casperian strip in roots) also play an important role in mediating the resistance response. The present study provides the first ever comprehensive insights into transcriptional changes among M. chitwoodi resistant and susceptible potato genotypes after nematode inoculation. The knowledge generated in the present study has implications in breeding for CRKN resistance in potato.

C-13 Sex Differences in Cognitive and Neurobiological Markers of Alzheimer's Disease

Objective

Previous work has demonstrated that intra-individual cognitive variability (IICV) has predictive power similar to traditional Alzheimer’s disease (AD) biomarkers, such as CSF or hippocampal volume (HV) loss. Genetic factors, such as sex, have been identified as predictors of cognitive decline. Analysis of sex differences in IICV and other biomarkers may elucidate additional dimensions of this metric.

Method

Baseline neurocognitive test and neuroimaging data from 335 participants with ≥2 visits enrolled in the Wisconsin Alzheimer’s Disease Research Center Clinical Core were included. Z-scores were calculated comparing individual performance to group performance by test (Rey Auditory Verbal Learning Test (Learning and Delayed Recall), Trail Making Test (A and B), and either Boston Naming Test (BNT) or Multilingual Naming Test (MINT)). MINT scores were converted to BNT scores using the NACC Crosswalk Study. The standard deviation of z-scores across tests was calculated to determine IICV. Characteristics by sex were compared using Mann-Whitney and Fisher’s Exact tests. Spearman’s Rho was calculated to compare IICV and HV (relative to intercranial volume).

Results

At baseline (Table 1): (1) Males had more education than females; (2) females had both higher relative HV and IICV; and (3) in females, relative HV demonstrated a weak positive correlation with baseline IICV (Figure 1).

Conclusions

IICV has previously demonstrated potential as a cost-effective non-invasive marker of preclinical AD. In females, larger relative HV and its correlation with IICV may be due to differences in metabolic brain age or concurrent progression of HV and IICV through the AD process. Analyses of other biopsychosocial factors are needed.

C-12 Race and Sex Differences in Cognitive and Neurobiological Markers of Alzheimer's Disease

Objective

Intra-Individual Cognitive Variability (IICV) previously demonstrated predictive power similar to AD biomarkers (i.e., CSF and hippocampal volume (HV) loss). Previous work suggested sex differences in relative HV and IICV. Additionally, IICV differs in whites and underrepresented racial groups (URG). Our objective was to analyze these sex differences in white and URG participants.

Method

Baseline neurocognitive test and neuroimaging data from 335 cognitively healthy participants with ≥2 visits enrolled in the Wisconsin ADRC Clinical Core were included. Z-scores were calculated comparing individual performance to group performance by test (Rey Auditory Verbal Learning Test (Learning and Delayed Recall), Trail Making Test (A and B), and either Boston Naming Test (BNT) or Multilingual Naming Test (MINT)). MINT scores were converted to BNT scores using the NACC Crosswalk Study. The standard deviation of z-scores across tests was calculated to determine IICV. Characteristics by race and sex were compared using Mann-Whitney, Fisher’s Exact, and Kruskal-Wallis tests. Spearman’s Rho was calculated to compare baseline IICV and relative HV.

Results

At baseline (Table 1), differences across racial groups in age, years of education, relative HV, and IICV were identified. Sex and racial group differences were identified (Table 2). A weak positive correlation between HV and IICV was seen in white females (Figure 1).

Conclusions

IICV has potential to become a cost-effective, non-invasive marker of preclinical AD. Again, correlation between HV and IICV was seen, but only in white females. Analyses suggest group differences between white and URG males and females. However, more data is needed to further explore these differences.

First Measurement of Near-Threshold J/ψ Exclusive Photoproduction off the Proton

We report on the measurement of the γp→J/ψp cross section from E_{γ}=11.8  GeV down to the threshold at 8.2 GeV using a tagged photon beam with the GlueX experiment. We find that the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section dσ/dt has an exponential slope of 1.67±0.39  GeV^{-2} at 10.7 GeV average energy. The LHCb pentaquark candidates P_{c}^{+} can be produced in the s channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions B(P_{c}^{+}→J/ψp) and cross sections σ(γp→P_{c}^{+})×B(P_{c}^{+}→J/ψp).

Plant-parasitic nematode effectors - insights into their diversity and new tools for their identification

Plant-parasitic nematodes (PPNs) are a large group of obligate biotrophic pathogens that secrete molecules, called effectors, involved in parasitism. The majority of work in molecular phytonematology has focused on the root-knot and cyst nematodes, which are both sedentary endoparasitic nematodes. More recently, inexpensive sequencing technology has facilitated effector searches in PPNs with different parasitic lifestyles. Work in different PPN species suggests that effectors are diverse, and selection pressure from plant hosts has contributed to the presence of large, expanded effector gene families. The identification of promoter elements/motifs preceding effector gene sequences suggests that promoter analysis can computationally predict new putative effectors. However, until a method of genetic transformation is available for PPNs, work on characterizing effectors will be hindered.

Loop-Mediated Isothermal Amplification for the Diagnostic Detection of Meloidogyne chitwoodi and M. fallax

Meloidogyne chitwoodi is a root-knot nematode that parasitizes a broad range of plants. In the Pacific Northwest (PNW) of the United States, M. chitwoodi is a major potato pest. The nematodes infect roots and tubers; blemishes caused by the nematodes on the tubers significantly affect potato marketability. M. chitwoodi is a quarantine pathogen by many regulatory agencies, limiting potato trade opportunities when it is present. A loop-mediated isothermal amplification (LAMP) assay was developed to amplify the intergenic spacer (IGS2)-18S region of the ribosomal rDNA of M. chitwoodi. Using the LAMP assay, we could detect the presence of M. chitwoodi from infected Washington State soil samples. The LAMP primers showed specificity for DNA from M. chitwoodi and the closely related species M. fallax. There was no cross reaction of the LAMP primers with DNA from tropical nematodes M. incognita, M. arenaria, and M. javanica, or the Northern root-knot nematode M. hapla. The LAMP assays can be completed within 45 min, and they were 100 times more sensitive in nematode detection than conventional PCR. The LAMP assay will facilitate detection of potato nematodes M. chitwoodi and M. fallax. Knowledge of potato nematodes, particularly M. chitwoodi in PNW soils, will aid management decisions.

The root-knot nematode effector MiPFN3 disrupts plant actin filaments and promotes parasitism

Root-knot nematodes secrete effectors that manipulate their host plant cells so that the nematode can successfully establish feeding sites and complete its lifecycle. The root-knot nematode feeding structures, their “giant cells,” undergo extensive cytoskeletal remodeling. Previous cytological studies have shown the cytoplasmic actin within the feeding sites looks diffuse. In an effort to study root-knot nematode effectors that are involved in giant cell organogenesis, we have identified a nematode effector called MiPFN3 (Meloidogyne incognita Profilin 3). MiPFN3 is transcriptionally up-regulated in the juvenile stage of the nematode. In situ hybridization experiments showed that MiPFN3 transcribed in the nematode subventral glands, where it can be secreted by the nematode stylet into the plant. Moreover, Arabidopsis plants that heterologously expressed MiPFN3 were more susceptible to root-knot nematodes, indicating that MiPFN3 promotes nematode parasitism. Since profilin proteins can bind and sequester actin monomers, we investigated the function of MiPFN3 in relation to actin. Our results show that MiPFN3 suppressed the aberrant plant growth phenotype caused by the misexpression of reproductive actin (AtACT1) in transgenic plants. In addition, it disrupted actin polymerization in an in vitro assay, and it reduced the filamentous actin network when expressed in Arabidopsis protoplasts. Over a decade ago, cytological studies showed that the cytoplasmic actin within nematode giant cells looked fragmented. Here we provide the first evidence that the nematode is secreting an effector that has significant, direct effects on the plant’s actin cytoskeleton.

Root-knot nematodes are microscopic plant pests that infect plant roots and significantly reduce yields of many crop plants. The nematodes enter the plant roots and modify plant cells into complex, multinuclear feeding sites called giant cells. The formation and maintenance of giant cells is critical to nematode survival. During giant cell organogenesis, the progenitor plant cells undergo many morphological changes, including a re-organization of the cytoplasmic actin cytoskeleton. As a result, the giant cell cytoplasmic actin appears fragmented and disorganized. Plant cells can regulate their actin filament assembly, in part, through the expression of actin binding proteins such as profilins. Here we show that infectious nematode juveniles express a profilin called MiPFN3. Expression of MiPFN3 in Arabidopsis plants made the plants more susceptible to root-knot nematodes, indicating that MiPFN3 acts as an effector that aids parasitism. We show evidence that the expression MiPFN3 in plant cells causes the fragmentation of plant actin filaments. The work here demonstrates that nematode effector MiPFN3 can directly affect plant actin filaments, whose reorganization is necessary for giant cell formation.

First Exclusive Measurement of Deeply Virtual Compton Scattering off ^{4}He: Toward the 3D Tomography of Nuclei

We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized ^{4}He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling ^{4}He nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only ^{4}He Compton form factor, H_{A}. This first measurement of coherent deeply virtual Compton scattering on the ^{4}He nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.

W342F Mutation in CCaMK Enhances Its Affinity to Calmodulin But Compromises Its Role in Supporting Root Nodule Symbiosis in Medicago truncatula

The calcium/calmodulin-dependent protein kinase (CCaMK) is regulated by free Ca2+ and Ca2+-loaded calmodulin. This dual binding is believed to be involved in its regulation and associated physiological functions, although direct experimental evidence for this is lacking. Here we document that site-directed mutations in the calmodulin-binding domain of CCaMK alters its binding capacity to calmodulin, providing an effective approach to study how calmodulin regulates CCaMK in terms of kinase activity and regulation of rhizobial symbiosis in Medicago truncatula. We observed that mutating the tryptophan at position 342 to phenylalanine (W342F) markedly increased the calmodulin-binding capability of the mutant. The mutant CCaMK underwent autophosphorylation and catalyzed substrate phosphorylation in the absence of calcium and calmodulin. When the mutant W342F was expressed in ccamk-1 roots, the transgenic roots exhibited an altered nodulation phenotype. These results indicate that altering the calmodulin-binding domain of CCaMK could generate a constitutively activated kinase with a negative role in the physiological function of CCaMK.

Autophosphorylation of calcium/calmodulin-dependent protein kinase (CCaMK) at S343 or S344 generates an intramolecular interaction blocking the CaM-binding

The Ca²⁺ and Ca²⁺/calmodulin-dependent protein kinase (CCaMK) is an important effector protein of Ca²⁺/calmodulin-mediated signaling, and in legumes, it is a critical regulator of plant-rhizobia and mycorrhizal symbioses. CCaMK contains a kinase domain, a calmodulin-binding/autoinhibitory domain and a visinin-like domain. Previous studies revealed the presence of 2 phosphorylation sites, S343 and S344, in the calmodulin-binding domain. Mutations at these sites affected the kinase activity and downstream rhizobium and mycorrhizal symbioses, which highlighted the importance of these residues in regulating protein activity. This addendum further clarifies the regulation of CCaMK by identifying an intramolecular interaction between residue(s) in the kinase domain and phosphorylation sites S343 and S344. This interaction turns off the substrate phosphorylation capacity of CCaMK.

Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π^{-}p in the N^{*} Resonance Region

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN^{*} resonance photocouplings.

Identification of Two Meloidogyne hapla Genes and an Investigation of Their Roles in the Plant-Nematode Interaction

Root-knot nematodes are soil-borne pathogens that invade and establish feeding sites in plant roots. They have an extremely broad host range, including most vascular plants. During infection of a susceptible host, root-knot nematodes secrete molecules called effectors that help them establish an intimate interaction with the plant and, at the same time, allow them to evade or suppress plant immune responses. Despite the fact that Meloidogyne hapla is a significant pest on several food crops, no effectors have been characterized from this root-knot nematode species thus far. Using the published genome and proteome from M. hapla, we have identified and characterized two genes, MhTTL2 and Mh265. MhTTL2 encodes a predicted secreted protein containing a transthyretin-like protein domain. The expression of MhTTL2 was up-regulated during parasitic life stages of the nematode, and in situ hybridization showed that MhTTL2 was expressed in the amphids, suggesting it has a role in the nematode nervous system during parasitism. We also studied the gene Mh265. The Mh265 transcript was localized to the subventral esophageal glands. An upregulation in Mh265 expression coincided with the pre- and early-parasitic life stages of the nematode. When Mh265 was constitutively expressed in plants, it enhanced their susceptibility to nematodes. These transgenic plants were also compromised in flg22-induced callose deposition, suggesting the Mh265 is modulating plant basal immune responses.

OPDA Has Key Role in Regulating Plant Susceptibility to the Root-Knot Nematode Meloidogyne hapla in Arabidopsis

Jasmonic acid (JA) is a plant hormone that plays important roles in regulating plant defenses against necrotrophic pathogens and herbivorous insects, but the role of JA in mediating the plant responses to root-knot nematodes has been unclear. Here we show that an application of either methyl jasmonate (MeJA) or the JA-mimic coronatine (COR) on Arabidopsis significantly reduced the number of galls caused by the root-knot nematode Meloidogyne hapla. Interestingly, the MeJA-induced resistance was independent of the JA-receptor COI1 (CORONATINE INSENSITIVE 1). The MeJA-treated plants accumulated the JA precursor cis-(+)-12-oxo-phytodienoic acid (OPDA) in addition to JA/JA-Isoleucine, indicating a positive feedback loop in JA biosynthesis. Using mutants in the JA-biosynthetic pathway, we found that plants deficient in the biosynthesis of JA and OPDA were hyper-susceptible to M. hapla. However, the opr3 mutant, which cannot convert OPDA to JA, exhibited wild-type levels of nematode galling. In addition, mutants in the JA-biosynthesis and perception which lie downstream of opr3 also displayed wild-type levels of galling. The data put OPR3 (OPDA reductase 3) as the branch point between hyper-susceptibility and wild-type like levels of disease. Overall, the data suggests that the JA precursor, OPDA, plays a role in regulating plant defense against nematodes.

Effects of testosterone administration on cognitive function in hysterectomized women with low testosterone levels: a dose-response randomized trial

PURPOSE

To determine the dose-dependent effects of testosterone administration on cognition in women with low testosterone levels.

METHODS

71 hysterectomized women with or without oophorectomy with total testosterone <31 ng/dl and/or free testosterone <3.5 pg/ml received a standardized transdermal estradiol regimen during the 12-week run-in period and were then randomized to receive weekly intramuscular injections of placebo, 3, 6.25, 12.5, or 25 mg testosterone enanthate for 24 weeks. Total testosterone was measured in serum by LC-MS/MS, and free testosterone levels were measured by equilibrium dialysis. Cognitive function was evaluated using a comprehensive battery of standardized neuropsychological tests at baseline and 24 weeks.

RESULTS

46 women who had baseline and end-of-treatment cognitive function data constituted the analytic sample. The five groups were similar at baseline. Mean on-treatment nadir total testosterone concentrations were 15, 89, 98, 134, and 234 ng/dl in the placebo, 3, 6.25, 12.5, and 25 mg groups, respectively. No significant changes in spatial ability, verbal fluency, verbal memory, or executive function were observed in any treatment arm compared to placebo even after adjustment for baseline cognitive function, age, and education. Multiple regression analysis did not show any significant relation between changes in testosterone concentrations and change in cognitive function scores.

CONCLUSION

Short-term testosterone administration over a wide range of doses for 24 weeks in women with low testosterone levels was neither associated with improvements nor worsening of cognitive function.

Standardizing morphine use for ventilated preterm neonates with a nursing-driven comfort protocol

OBJECTIVE

To test whether implementing a nursing-driven comfort protocol standardizes morphine use in one neonatal intensive care unit (NICU) and to examine how non-standard morphine (N-SM) relates to days of ventilation, days of total parenteral nutrition (TPN) and length of stay (LOS).

STUDY DESIGN

This was a retrospective/prospective observational study using pharmacy records, medical records, and an outcomes database. Comfort protocol implementation began February 2011 and was applied to preterm, ventilated neonates <1500 grams. Pre- and post-implementation proportions of N-SM days were compared using the binomial test. A percent 'P'-chart spanning 30 quarters was constructed with statistical-process control analysis. Multivariable linear regression adjusting for acuity assessed the relationship between N-SM use and days of ventilation, TPN and LOS.

RESULT

Hundred and thirty-four patients met inclusion criteria, 116 prior to and 18 after implementation. The proportion of patients given N-SM for one or more days decreased from 59 to 35% after protocol implementation (P = 0.017). A 9-month period of decreased N-SM days was observed after protocol implementation. Controlling for acuity, each additional day of N-SM use was associated with 0.47 more days of ventilation (95% confidence interval (CI): 0.26-0.69, P < 0.001) and 0.52 more days of TPN (95% CI: 0.35-0.68, P < 0.001). Exposure to N-SM was associated with 17 additional days of hospitalization (P = 0.009, 95% CI: 4.5-30).

CONCLUSION

Implementing a nursing-driven comfort protocol significantly reduced N-SM use. N-SM in the NICU is negatively associated with key clinical outcomes. Testing similar protocols in other settings is warranted.

Mutant analysis in Arabidopsis provides insight into the molecular mode of action of the auxinic herbicide dicamba

Herbicides that mimic the natural auxin indole-3-acetic acid are widely used in weed control. One common auxin-like herbicide is dicamba, but despite its wide use, plant gene responses to dicamba have never been extensively studied. To further understand dicamba's mode of action, we utilized Arabidopsis auxin-insensitive mutants and compared their sensitivity to dicamba and the widely-studied auxinic herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The mutant axr4-2, which has disrupted auxin transport into cells, was resistant to 2,4-D but susceptible to dicamba. By comparing dicamba resistance in auxin signalling F-box receptor mutants (tir1-1, afb1, afb2, afb3, and afb5), only tir1-1 and afb5 were resistant to dicamba, and this resistance was additive in the double tir1-1/afb5 mutant. Interestingly, tir1-1 but not afb5 was resistant to 2,4-D. Whole genome analysis of dicamba-induced gene expression showed that 10 hours after application, dicamba stimulated many stress-responsive and signalling genes, including those involved in biosynthesis or signalling of auxin, ethylene, and abscisic acid (ABA), with TIR1 and AFB5 required for the dicamba-responsiveness of some genes. Research into dicamba-regulated gene expression and the selectivity of auxin receptors has provided molecular insight into dicamba-regulated signalling and could help in the development of novel herbicide resistance in crop plants.

The B-3 ethylene response factor MtERF1-1 mediates resistance to a subset of root pathogens in Medicago truncatula without adversely affecting symbiosis with rhizobia

The fungal necrotrophic pathogen Rhizoctonia solani is a significant constraint to a range of crops as diverse as cereals, canola, and legumes. Despite wide-ranging germplasm screens in many of these crops, no strong genetic resistance has been identified, suggesting that alternative strategies to improve resistance are required. In this study, we characterize moderate resistance to R. solani anastomosis group 8 identified in Medicago truncatula. The activity of the ethylene- and jasmonate-responsive GCC box promoter element was associated with moderate resistance, as was the induction of the B-3 subgroup of ethylene response transcription factors (ERFs). Genes of the B-1 subgroup showed no significant response to R. solani infection. Overexpression of a B-3 ERF, MtERF1-1, in Medicago roots increased resistance to R. solani as well as an oomycete root pathogen, Phytophthora medicaginis, but not root knot nematode. These results indicate that targeting specific regulators of ethylene defense may enhance resistance to an important subset of root pathogens. We also demonstrate that overexpression of MtERF1-1 enhances disease resistance without apparent impact on nodulation in the A17 background, while overexpression in sickle reduced the hypernodulation phenotype. This suggests that under normal regulation of nodulation, enhanced resistance to root diseases can be uncoupled from symbiotic plant-microbe interactions in the same tissue and that ethylene/ERF regulation of nodule number is distinct from the defenses regulated by B-3 ERFs. Furthermore, unlike the stunted phenotype previously described for Arabidopsis (Arabidopsis thaliana) ubiquitously overexpressing B-3 ERFs, overexpression of MtERF1-1 in M. truncatula roots did not show adverse effects on plant development.

Nodulation independent of rhizobia induced by a calcium-activated kinase lacking autoinhibition

Legumes, such as Medicago truncatula, form mutualistic symbiotic relationships with nitrogen-fixing rhizobial bacteria. This occurs within specialized root organs--nodules--that provide the conditions required for nitrogen fixation. A rhizobium-derived signalling molecule, Nod factor, is required to establish the symbiosis. Perception of Nod factor in the plant leads to the induction of Ca2+ oscillations, and the transduction of this Ca2+ signal requires DMI3 (refs 2, 3), which encodes the protein kinase Ca2+/calmodulin-dependent protein kinase (CCaMK). Central to the regulation of CCaMK is an autoinhibitory domain that negatively regulates kinase activity. Here we show that the specific removal of the autoinhibition domain leads to the autoactivation of the nodulation signalling pathway in the plant, with the resultant induction of nodules and nodulation gene expression in the absence of bacterial elicitation. This autoactivation requires nodulation-specific transcriptional regulators in the GRAS family. This work demonstrates that the release of autoinhibition from CCaMK after calmodulin binding is a central switch that is sufficient to activate nodule morphogenesis. The fact that a single regulation event is sufficient to induce nodulation highlights the possibility of transferring this process to non-legumes.

Nodulation signaling in legumes requires NSP2, a member of the GRAS family of transcriptional regulators

Rhizobial bacteria enter a symbiotic interaction with legumes, activating diverse responses in roots through the lipochito oligosaccharide signaling molecule Nod factor. Here, we show that NSP2 from Medicago truncatula encodes a GRAS protein essential for Nod-factor signaling. NSP2 functions downstream of Nod-factor-induced calcium spiking and a calcium/calmodulin-dependent protein kinase. We show that NSP2-GFP expressed from a constitutive promoter is localized to the endoplasmic reticulum/nuclear envelope and relocalizes to the nucleus after Nod-factor elicitation. This work provides evidence that a GRAS protein transduces calcium signals in plants and provides a possible regulator of Nod-factor-inducible gene expression.

Development of an equilibrium immunoassay using electrochemiluminescent detection for a novel recombinant protein product and its application to pre-clinical product development

In order for a biotechnology derived protein product to be considered 'well characterized', a thorough understanding of the pharmacokinetic and metabolic fate of the product is essential. Specifications for such products need to be based on historical data obtained in the pre-clinical, clinical and manufacturing experience through the use of specific, accurate, precise and validated assays. Typically, assays such as ELISA or RIA that have the disadvantages of limited dynamic range, matrix interactions and hazardous waste generation are used to gather this data. We present data in this abstract that demonstrates the utility of an equilibrium immunoassay that uses electrochemiluminescent detection in the assessment of the pharmacokinetic and metabolic fate of a biotechnology derived product based on either the human (AMG1h) or murine (AMG1m) protein sequence. The assay uses biotinylated antibody in a sandwich format with antibody labeled with the N-hydroxysuccinimide ester of a ruthenium (II) tris-bipyridine chelate for detection in the Origen System. Streptavidin-coated paramagnetic beads are used to capture the antibody-antigen-antibody sandwich complex and facilitate electrochemiluminescent detection. The assay standard curve for AMG1h ranges from a lower limit of quantitation (LOQ) of 2.5 ng ml(-1) to an upper limit of quantitation (ULQ) of 2000 ng ml(-1) with accuracy and precision of not greater then 15% CV and deviation from nominal over the range. The corresponding LOQ (0.5 ng ml(-1)) and ULQ (200 ng ml(-1)) values determined for AMG1m displayed similar accuracy and precision. In addition, we demonstrate that the assay as performed is insensitive to matrix effect up to addition of 7%, of the total reaction volume. General guidelines for developing similar electrochemiluminescent based assays and their applications, advantages and limitations will be discussed.

Effects of age, gender, and diurnal variation on the steady-state pharmacokinetics of BMS-181101, an antidepressant, in healthy subjects

OBJECTIVES

To investigate the effects of age, gender, and diurnal variation on the safety, tolerability, and steady-state pharmacokinetics of BMS-181101, an antidepressant, in humans.

METHODS

This was a multiple-dose parallel-design study in 51 healthy subjects (12 young and 12 elderly men and 12 young and 15 elderly women). Each subject received a 15 mg oral dose of BMS-181101 every 12 hours on days 1 through 6 and one dose on day 7. After the evening dose on day 6 and morning dose on day 7, serial blood samples were collected at specified times after administration. Plasma was analyzed for BMS-181101 with use of an HPLC method.

RESULTS

Male subjects tolerated BMS-181101 better than female subjects. The mean values for area under the plasma concentration-time curve over the dosing interval tau (AUC tau; 58.8 to 102.4 ng.hr/ml) and elimination half-life t1/2; 5.7 to 10.4 hours) for the elderly subjects were significantly greater than those for the young subjects (39.0 to 64.3 ng.hr/ml and 3.2 to 4.5 hours). The mean values for peak plasma concentration (Cmax; 14.7 to 25.2 ng/ml) and AUC tau (52.4 to 102.4 ng.hr/ml) for the women were significantly greater than those for the men (9.08 to 15.3 ng/ml and 39.0 to 73.6 ng.hr/ml). The mean values for Cmax (14.7 to 25.2 ng/ml) and AUC tau (54.8 to 102.4 ng.hr/ml) on the morning of day 7 were significantly greater than those after the evening dose on day 6 (9.08 to 17.3 ng/ml; 39.0 to 83.4 ng.hr/ml).

CONCLUSIONS

An initial lower dose or appropriate titration of daily doses of BMS-181101 may be necessary for the treatment of elderly and female subjects, and the pharmacokinetics of BMS-181101 exhibited significant diurnal effects.

Possible antioxidant effect of vitamin A supplementation in premature infants

BACKGROUND

Increased lipid peroxidation caused by oxygen free radicals is thought to be one of the common pathogenetic mechanisms for the so-called oxygen radical diseases of prematurity. Since in vitro studies have shown that various forms of vitamin A can exert antioxidant effects that are more potent than those of vitamin E (treatment with which has been ineffective in these diseases), the purpose of this prospective, controlled study was to determine whether administration of supplemental vitamin A to premature infants deficient in this vitamin would have an antioxidant effect in vivo.

METHODS

Fourteen infants (1181 +/- 35 g; gestational age 29 +/- 0.04 weeks) with a serum retinol concentration at 7 +/- 2 days of age in the deficient range, lower than 0.7 mumol/l (< 20 micrograms/dl), were enrolled in the study. Infants were randomized to receive the standard amount of vitamin A or standard plus supplemental (2.6 mumol/l [2500 IU] orally each day) vitamin A, beginning at 1 week of age. Antioxidant effects of supplementation were assessed by a decrease in lipid peroxidation, quantified by the ethane content of expired air.

RESULTS

Three weeks after study enrollment, total daily vitamin A intake in the infants receiving supplements was 4.565 +/- 0.236 mumol (4354 +/- 225 IU) versus 1.879 +/- 0.317 mumol/l (1792 +/- 302 IU) in infants receiving standard amounts of the vitamin. In spite of the difference in intake of vitamin A, 3 weeks after study enrollment, serum retinol concentrations did not differ between the infants given supplements and those receiving standard amounts of vitamin A, 0.70 +/- 0.21 versus 0.66 +/- 0.07 mumol/l (20 +/- 6 micrograms/dl versus 19 +/- 2 micrograms/dl, respectively). In the infants receiving supplemental vitamin A, breath ethane values declined from baseline values. There was an inverse correlation between the number of weeks of supplementation and breath ethane values, whereas there was no significant correlation between the duration of the study and breath ethane values in the infants not given supplements.

CONCLUSIONS

Our data suggest that supplementation with vitamin A in a small group of vitamin A-deficient preterm infants was associated with an antioxidant effect. Although no immediate clinical benefits were associated with supplementation, the data provide the rationale for future investigations of possible antioxidant effects of (larger amounts?) of vitamin A in higher risk premature infants born with subnormal serum retinol concentrations.

Pneumocandins from Zalerion arboricola. I. Discovery and isolation

HPLC bioautography of the directed biosynthesis of Zalerion arboricola led to the discovery of pneumocandin B0 (L-688,786), a new antifungal and anti-Pneumocystis carinii lipopeptide. Isolation techniques were developed to separate this component from pneumocandin A0 (L-671,329) in fermentations of a mutant of Zalerion arboricola. A number of related compounds were also isolated, which differ from pneumocandins A0 and B0 in the hydroxylation patterns on the ornithine, homotyrosine, and proline.

Efficacy and pharmacokinetics of intravenous immune globulin administration to high-risk neonates

OBJECTIVE--To determine whether intravenous immune globulin (IVIG) administration modifies the incidence of infections in high-risk neonates. DESIGN--Randomized, double-blind study. SETTING--Neonatal intensive care unit at a tertiary care center.

PARTICIPANTS

A total of 170 infants were enrolled, 82 of whom received IVIG and 88 of whom received the placebo preparation. Infants were stratified by birth weight into one of three groups (category 1, those weighing less than 1000 g; category 2, those weighing between 1000 and 1500 g; and category 3, those weighing more than 1500 g). INTERVENTIONS--Intravenous immune globulin (750 mg/kg of body weight), or albumin placebo was administered within 72 hours of admission to the tertiary care center and every 14 days thereafter until discharge from the neonatal intensive care unit or age 3 months. Serum IgG levels were measured and data collected relating to the incidence of systemic and localized infections and to the course of hospitalization. MEASUREMENTS AND MAIN RESULTS--The administration of IVIG had no major side effects and resulted in higher serum IgG levels in infants in all birth weight categories compared with infants receiving the placebo. Systemic infections developed in five IVIG-treated infants and five placebo-treated infants. Administration of immunoglobulin had no significant effect on the rate of localized infections or necrotizing enterocolitis. It also did not affect hospital course of the infants as measured by length of hospitalization or the number of days on assisted ventilation, supplemental oxygen, or antibiotics was required. CONCLUSIONS--The general administration of IVIG using this dosage regimen has limited effects on the clinical course of infants in a neonatal intensive care unit.

Fluidized bed adsorption for whole broth extraction

Fluidized bed adsorption using a high-density synthetic resin has proven to be an invaluable technique for separating novel compounds from unfiltered fermentation broths during the very early stages of fermentation development, where product concentrations are typically in the parts per million range. Previous initial downstream processing strategies consisted of cell separation from whole broth or direct extraction with water-immiscible solvents, both of which resulted in lengthy time cycles, conflicts with existing operations requiring the use of high-cost centrifugal separators, and environmental/solvent recovery concerns. Laboratory and subsequent pilot plant process development work along with concomitant improvements in yield, quality, and time cycles are presented for one of several fluidized bed processes piloted in Merck's Natural Product Isolation facility.

Sleep disturbance produced by electrical stimulation of the locus coeruleus in a human subject

A 25-year-old man with a chronically implanted stimulating electrode placed in the region of the locus coeruleus (LC) was monitored for 5 nights in a sleep laboratory to study the role of the LC in sleep. Sleep patterns were compared between the 2 nights in which the stimulation was applied periodically every 90 min and the 2 nights in which no stimulation was applied. In contrast to the normal sleep patterns that occurred during the 2 nonstimulation nights, electrical stimulation of the LC produced a profound disruption of sleep and significant reductions in the total amounts of NREM sleep, REM sleep, REM sleep as a percent of total sleep (NREM + REM sleep), and total sleep. Results suggest that the LC has a role in maintaining normal sleep patterns.

Adverse effect of splenectomy in experimental peritonitis

Patients undergoing splenectomy have increased operative morbidity and mortality, especially when associated with gastrointestinal surgery or injury. This present study was designed to assess the effect of splenectomy on mortality in a polymicrobial fecal peritonitis model and evaluate therapy with antibiotic (cefoxitin) or immunomodulation (glucan). Human stool-barium (0.15 cc) was placed in the peritoneum of Sprague-Dawley rats at the time of splenectomy or sham surgery. Splenectomy animals were then treated with 5% dextrose, cefoxitin (60 mg im q 6 hr), glucan (7.5 mg ip prior to surgery), or cefoxitin plus glucan. Splenectomy resulted in decreased survival (5% vs 30%, P less than 0.05). Treatment with cefoxitin (90%) or glucan (47%) significantly improved survival. Combined glucan-cefoxitin therapy had no improvement over cefoxitin alone. Peritoneal and blood cultures were performed 12 hr postoperatively. There were no significant differences in growth of bacteria between sham and splenectomy animals. Cefoxitin treatment resulted in lower growth of bacteria from both blood and peritoneum (P less than 0.05). Glucan treatment caused a significant decrease in the number of bloodborne bacteria (P less than 0.05). Intravascular colloidal carbon clearance and leucocyte counts were performed at 12 hr postoperatively. Presence of peritonitis significantly enhanced intravascular clearance, while splenectomy had no effect. Addition of glucan or cefoxitin therapy to splenectomy animals did not enhance intravascular clearance. Leucocyte counts were significantly lower (P less than 0.05) when splenectomy was added to peritonitis animals. Glucan and cefoxitin therapy did not increase leucocyte counts. Based on these studies we conclude that (1) splenectomy increases mortality in fecal peritonitis, (2) antibiotic and immunomodulator afford some protection, and (3) exact mechanism of protection remains unclear.

Etiology of acute conjunctivitis in children

To determine the etiology of acute conjunctivitis in children seen in pediatric practice, 99 patients with conjunctivitis and 102 age-and season-matched controls were cultured for aerobic bacteria including Haemophilus influenzae, and for viruses, Chlamydia trachomatis, and mycoplasmas. Agents statistically associated with conjunctivitis included H. influenzae (42% vs 0%), Streptococcus pneumoniae (12% vs 3%), and adenoviruses (20% vs 0%). One of these three etiologic agents was isolated from 71 (72%) of the patients. Simultaneous infection with two pathogens was uncommon. Staphylococcus aureus was equally prevalent in diseased and control eyes; one strain of C. trachomatis was isolated from a control eye. Although there were variations in the clinical features of viral and bacterial conjunctivitis, differentiation in an individual patient was difficult. An adenovirus was isolated from 11 (65%) of 17 patients who had pharyngitis in addition to conjunctivitis. H. influenzae was isolated from 14 (74%) of 19 children who had both otitis and conjunctivitis. Adenovirus conjunctivitis was common in the fall and H. influenzae in winter.

A comparative study of bacampicillin hydrochloride, penicillin V, and amoxicillin in the treatment of acute tonsillitis and/or pharyngitis due to beta-hemolytic streptococci

Fifty-five outpatients with acute tonsillitis and/or pharyngitis due to group A beta-hemolytic streptococci were treated during 1978 and 1979. Twenty-nine patients received 400 mg of bacampicillin twice a day, 21 patients received 250 mg of penicillin V four times a day, and five patients received 250 mg of amoxicillin every 8 hr. All except one patient, who was treated with bacampicillin, had a satisfactory clinical response to treatment. The bacteriologic response was satisfactory in all but one patient. None of the 55 patients developed adverse effects that necessitated the discontinuance of the antibiotic in use. No significant differences were found between the clinical or the bacteriologic responses to bacampicillin, penicillin V, or amoxicillin (Fisher's exact test).