A fungal sesquiterpene biosynthesis gene cluster critical for mutualist-pathogen transition in Colletotrichum tofieldiae

Plant-associated fungi show diverse lifestyles from pathogenic to mutualistic to the host; however, the principles and mechanisms through which they shift the lifestyles require elucidation. The root fungus Colletotrichum tofieldiae (Ct) promotes Arabidopsis thaliana growth under phosphate limiting conditions. Here we describe a Ct strain, designated Ct3, that severely inhibits plant growth. Ct3 pathogenesis occurs through activation of host abscisic acid pathways via a fungal secondary metabolism gene cluster related to the biosynthesis of sesquiterpene metabolites, including botrydial. Cluster activation during root infection suppresses host nutrient uptake-related genes and changes mineral contents, suggesting a role in manipulating host nutrition state. Conversely, disruption or environmental suppression of the cluster renders Ct3 beneficial for plant growth, in a manner dependent on host phosphate starvation response regulators. Our findings indicate that a fungal metabolism cluster provides a means by which infectious fungi modulate lifestyles along the parasitic-mutualistic continuum in fluctuating environments.

Synergistic and Offset Effects of Fungal Species Combinations on Plant Performance

In natural and agricultural ecosystems, survival and growth of plants depend substantially on residing microbes in the endosphere and rhizosphere. Although numerous studies have reported the presence of plant-growth promoting bacteria and fungi in below-ground biomes, it remains a major challenge to understand how sets of microbial species positively or negatively affect plants' performance. By conducting a series of single- and dual-inoculation experiments of 13 plant-associated fungi targeting a Brassicaceae plant species (Brassica rapa var. perviridis), we here systematically evaluated how microbial effects on plants depend on presence/absence of co-occurring microbes. The comparison of single- and dual-inoculation experiments showed that combinations of the fungal isolates with the highest plant-growth promoting effects in single inoculations did not have highly positive impacts on plant performance traits (e.g., shoot dry weight). In contrast, pairs of fungi with small/moderate contributions to plant growth in single-inoculation contexts showed the greatest effects on plants among the 78 fungal pairs examined. These results on the offset and synergistic effects of pairs of microbes suggest that inoculation experiments of single microbial species/isolates can result in the overestimation or underestimation of microbial functions in multi-species contexts. Because keeping single-microbe systems under outdoor conditions is impractical, designing sets of microbes that can maximize performance of crop plants is an important step for the use of microbial functions in sustainable agriculture.

Uncoupling root hair formation and defence activation from growth inhibition in response to damage-associated Pep peptides in Arabidopsis thaliana

In Arabidopsis thaliana, PROPEPs and their derived elicitor-active Pep epitopes provide damage-associated molecular patterns (DAMPs), which trigger defence responses through cell-surface receptors PEPR1 and PEPR2. In addition, Pep peptides induce root growth inhibition and root hair formation, however their relationships and coordinating mechanisms are poorly understood. Here, we reveal that Pep1-mediated root hair formation requires PEPR-associated kinases BAK1/BKK1 and BIK1/PBL1, ethylene, auxin and root hair differentiation regulators, in addition to PEPR2. Our analysis on 69 accessions unravels intraspecies variations in Pep1-induced root hair formation and growth inhibition. The absence of a positive correlation between the two traits suggests their separate regulation and diversification in natural populations of A. thaliana. Restricted PEPR2 expression to certain root tissues is sufficient to induce root hair formation and growth inhibition in response to Pep1, indicating the capacity of non-cell-autonomous receptor signalling in different root tissues. Of particular note, root hair cell-specific PEPR2 expression uncouples defence activation from root growth inhibition and root hair formation, suggesting a unique property of root hairs in root defence activation following Pep1 recognition.

SUPPRESSOR OF GAMMA RESPONSE 1 acts as a regulator coordinating crosstalk between DNA damage response and immune response in Arabidopsis thaliana

Plants live in constantly changing and often unfavorable or stressful environments. Environmental changes induce biotic and abiotic stress, which, in turn, may cause genomic DNA damage. Hence, plants simultaneously suffer abiotic/biotic stress and DNA damage. However, little information is available on the signaling crosstalk that occurs between DNA damage and abiotic/biotic stresses. Arabidopsis thaliana SUPPRESSOR OF GAMMA RESPONSE1 (SOG1) is a pivotal transcription factor that regulates thousands of genes in response to DNA double-strand break (DSB), and we recently reported that SOG1 has a role in immune responses. In the present study, the effects of SOG1 overexpression on the DNA damage and immune responses were examined. Results found that SOG1 overexpression enhances the regulation of numerous downstream genes. Relative to the wild type plants, then, DNA damage responses were observed to be strongly induced. SOG1 overexpression also upregulates chitin (a major components of fungal cell walls) responsive genes in the presence of DSBs, implying that pathogen defense response is activated by DNA damage via SOG1. Further, SOG1 overexpression enhances fungal resistance. These results suggest that SOG1 regulates crosstalk between DNA damage response and the immune response and that plants have evolved a sophisticated defense network to contend with environmental stress.

Roles of Plant-Derived Secondary Metabolites during Interactions with Pathogenic and Beneficial Microbes under Conditions of Environmental Stress

Under natural conditions, plants generate a vast array of secondary metabolites. Several of these accumulate at widely varying levels in the same plant species and are reportedly critical for plant adaptation to abiotic and/or biotic stresses. Some secondary metabolite pathways are required for beneficial interactions with bacterial and fungal microbes and are also regulated by host nutrient availability so that beneficial interactions are enforced. These observations suggest an interplay between host nutrient pathways and the regulation of secondary metabolites that establish beneficial interactions with microbes. In this review, I introduce the roles of tryptophan-derived and phenylpropanoid secondary-metabolite pathways during plant interactions with pathogenic and beneficial microbes and describe how these pathways are regulated by nutrient availability.

Publisher Correction: Core microbiomes for sustainable agroecosystems

Owing to a technical error, this Perspective was originally published without its received and accepted dates; the dates "Received: 31 December 2017; Accepted: 23 March 2018" have now been included in all versions.

Beneficial associations between Brassicaceae plants and fungal endophytes under nutrient-limiting conditions: evolutionary origins and host-symbiont molecular mechanisms

Brassicaceae plants have lost symbiotic interactions with mutualistic mycorrhizal fungi, but, nonmycorrhizal Brassicaceae associate with diverse taxonomic groups of mutualistic root-endophytic fungi. Distantly related fungal endophytes of Brassicaceae plants transfer phosphorus to the hosts and promote plant growth, thereby suggesting that the beneficial function was independently acquired via convergent evolution. These beneficial interactions appear tightly regulated by the tryptophan-derived secondary metabolite pathway, which specifically developed in Brassicaceae. Importantly, phosphate availability and types of colonizing microbes appear to influence the metabolite pathway. Thus, endophytes of Brassicaceae may have evolved to adapt to the Brassicaceae-specific traits. Future comparative functional analyses among well-defined endophytic fungi and their relatives with distinct life strategies and host plants will help understand the mechanisms that establish and maintain beneficial interactions.

Identifying the target genes of SUPPRESSOR OF GAMMA RESPONSE 1, a master transcription factor controlling DNA damage response in Arabidopsis

In mammalian cells, the transcription factor p53 plays a crucial role in transmitting DNA damage signals to maintain genome integrity. However, in plants, orthologous genes for p53 and checkpoint proteins are absent. Instead, the plant-specific transcription factor SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1) controls most of the genes induced by gamma irradiation and promotes DNA repair, cell cycle arrest, and stem cell death. To date, the genes directly controlled by SOG1 remain largely unknown, limiting the understanding of DNA damage signaling in plants. Here, we conducted a microarray analysis and chromatin immunoprecipitation (ChIP)-sequencing, and identified 146 Arabidopsis genes as direct targets of SOG1. By using ChIP-sequencing data, we extracted the palindromic motif [CTT(N)₇ AAG] as a consensus SOG1-binding sequence, which mediates target gene induction in response to DNA damage. Furthermore, DNA damage-triggered phosphorylation of SOG1 is required for efficient binding to the SOG1-binding sequence. Comparison between SOG1 and p53 target genes showed that both transcription factors control genes responsible for cell cycle regulation, such as CDK inhibitors, and DNA repair, whereas SOG1 preferentially targets genes involved in homologous recombination. We also found that defense-related genes were enriched in the SOG1 target genes. Consistent with this finding, SOG1 is required for resistance against the hemi-biotrophic fungus Colletotrichum higginsianum, suggesting that SOG1 has a unique function in controlling the immune response.

Integration of danger peptide signals with herbivore-associated molecular pattern signaling amplifies anti-herbivore defense responses in rice

Plant defense against herbivores is modulated by herbivore-associated molecular patterns (HAMPs) from oral secretions (OS) and/or saliva of insects. Furthermore, feeding wounds initiate plant self-damage responses modulated by danger-associated molecular patterns (DAMPs) such as immune defense-promoting plant elicitor peptides (Peps). While temporal and spatial co-existence of both patterns during herbivory implies a possibility of their close interaction, the molecular mechanisms remain undetermined. Here we report that exogenous application of rice (Oryza sativa) peptides (OsPeps) can elicit multiple defense responses in rice cell cultures. Specific activation of OsPROPEP3 gene transcripts in rice leaves by wounding and OS treatments further suggests a possible involvement of the OsPep3 peptide in rice-herbivore interactions. Correspondingly, we found that simultaneous application of OsPep3 and Mythimna loreyi OS significantly amplifies an array of defense responses in rice cells, including mitogen-activated protein kinase activation, and generation of defense-related hormones and metabolites. The induction of OsPROPEP3/4 by OsPep3 points to a positive auto-feedback loop in OsPep signaling which may contribute to additional enhancement of defense signal(s). Finally, the overexpression of the OsPep receptor OsPEPR1 increases the sensitivity of rice plants not only to the cognate OsPeps but also to OS signals. Our findings collectively suggest that HAMP-DAMP signal integration provides a critical step in the amplification of defense signaling in plants.

Core microbiomes for sustainable agroecosystems

In an era of ecosystem degradation and climate change, maximizing microbial functions in agroecosystems has become a prerequisite for the future of global agriculture. However, managing species-rich communities of plant-associated microbiomes remains a major challenge. Here, we propose interdisciplinary research strategies to optimize microbiome functions in agroecosystems. Informatics now allows us to identify members and characteristics of 'core microbiomes', which may be deployed to organize otherwise uncontrollable dynamics of resident microbiomes. Integration of microfluidics, robotics and machine learning provides novel ways to capitalize on core microbiomes for increasing resource-efficiency and stress-resistance of agroecosystems.

Glutathione Transferase U13 Functions in Pathogen-Triggered Glucosinolate Metabolism

Glutathione (GSH) and indole glucosinolates (IGs) exert key functions in the immune system of the model plant Arabidopsis (Arabidopsis thaliana). Appropriate GSH levels are important for execution of both pre- and postinvasive disease resistance mechanisms to invasive pathogens, whereas an intact PENETRATION2 (PEN2)-pathway for IG metabolism is essential for preinvasive resistance in this species. Earlier indirect evidence suggested that the latter pathway involves conjugation of GSH with unstable products of IG metabolism and further processing of the resulting adducts to biologically active molecules. Here we describe the identification of Glutathione-S-Transferase class-tau member 13 (GSTU13) as an indispensable component of the PEN2 immune pathway for IG metabolism. gstu13 mutant plants are defective in the pathogen-triggered biosynthesis of end products of the PEN2 pathway, including 4-O-β-d-glucosyl-indol-3-yl formamide, indole-3-ylmethyl amine, and raphanusamic acid. In line with this metabolic defect, lack of functional GSTU13 results in enhanced disease susceptibility toward several fungal pathogens including Erysiphe pisi, Colletotrichum gloeosporioides, and Plectosphaerella cucumerina Seedlings of gstu13 plants fail also to deposit the (1,3)-β-glucan cell wall polymer, callose, after recognition of the bacterial flg22 epitope. We show that GSTU13 mediates specifically the role of GSH in IG metabolism without noticeable impact on other immune functions of this tripeptide. We postulate that GSTU13 connects GSH with the pathogen-triggered PEN2 pathway for IG metabolism to deliver metabolites that may have numerous functions in the innate immune system of Arabidopsis.

Dysfunction of Arabidopsis MACPF domain protein activates programmed cell death via tryptophan metabolism in MAMP-triggered immunity

Plant immune responses triggered upon recognition of microbe-associated molecular patterns (MAMPs) typically restrict pathogen growth without a host cell death response. We isolated two Arabidopsis mutants, derived from accession Col-0, that activated cell death upon inoculation with nonadapted fungal pathogens. Notably, the mutants triggered cell death also when treated with bacterial MAMPs such as flg22. Positional cloning identified NSL1 (Necrotic Spotted Lesion 1) as a responsible gene for the phenotype of the two mutants, whereas nsl1 mutations of the accession No-0 resulted in necrotic lesion formation without pathogen inoculation. NSL1 encodes a protein of unknown function containing a putative membrane-attack complex/perforin (MACPF) domain. The application of flg22 increased salicylic acid (SA) accumulation in the nsl1 plants derived from Col-0, while depletion of isochorismate synthase 1 repressed flg22-inducible lesion formation, indicating that elevated SA is needed for the cell death response. nsl1 plants of Col-0 responded to flg22 treatment with an RBOHD-dependent oxidative burst, but this response was dispensable for the nsl1-dependent cell death. Surprisingly, loss-of-function mutations in PEN2, involved in the metabolism of tryptophan (Trp)-derived indole glucosinolates, suppressed the flg22-induced and nsl1-dependent cell death. Moreover, the increased accumulation of SA in the nsl1 plants was abrogated by blocking Trp-derived secondary metabolite biosynthesis, whereas the nsl1-dependent hyperaccumulation of PEN2-dependent compounds was unaffected when the SA biosynthesis pathway was blocked. Collectively, these findings suggest that MAMP-triggered immunity activates a genetically programmed cell death in the absence of the functional MACPF domain protein NSL1 via Trp-derived secondary metabolite-mediated activation of the SA pathway.

Colletotrichum higginsianum extracellular LysM proteins play dual roles in appressorial function and suppression of chitin-triggered plant immunity

The genome of the hemibiotrophic anthracnose fungus, Colletotrichum higginsianum, encodes a large repertoire of candidate-secreted effectors containing LysM domains, but the role of such proteins in the pathogenicity of any Colletotrichum species is unknown. Here, we characterized the function of two effectors, ChELP1 and ChELP2, which are transcriptionally activated during the initial intracellular biotrophic phase of infection. Using immunocytochemistry, we found that ChELP2 is concentrated on the surface of bulbous biotrophic hyphae at the interface with living host cells but is absent from filamentous necrotrophic hyphae. We show that recombinant ChELP1 and ChELP2 bind chitin and chitin oligomers in vitro with high affinity and specificity and that both proteins suppress the chitin-triggered activation of two immune-related plant mitogen-activated protein kinases in the host Arabidopsis. Using RNAi-mediated gene silencing, we found that ChELP1 and ChELP2 are essential for fungal virulence and appressorium-mediated penetration of both Arabidopsis epidermal cells and cellophane membranes in vitro. The findings suggest a dual role for these LysM proteins as effectors for suppressing chitin-triggered immunity and as proteins required for appressorium function.

Treatment of Relapsing Ph+ Acute Lymphoblastic Leukemia with Donor Leukocyte Infusion Followed by Quantitative Monitoring of Residual Disease

The case of a 34-year-old man with relapsing Ph+ acute lymphoblastic leukemia (ALL), which occurred five months after allogeneic bone marrow transplantation, is described. He was originally treated with aggressive chemotherapy, which put him in hematological remission, and he subsequently received donor leukocyte infusion (DLI) form the original donor. To assess the efficacy of this adoptive immunotherapy, we monitored minor-BCR/ABL (m-BCR/ABL) mRNA levels using the recently established real-time quantitative RT-PCR (RQ-PCR) assay. The results were compared with those obtained using conventional qualitative RT-PCR assays run in parallel. RQ-PCR, but not RT-PCR-based, minimum residual disease (MRD) detection showed a good correlation with the rapid changes documented during the post-DLI clinical course. Currently, six months after DLI, the patient continues to be in remission, which is consistent with the undetectable levels of m-BCR/ABL mRNA in the leukemic clone using RQ-PCR found in this study. Thus, monitoring of m-bcr/abl transcripts using RQ-PCR provides more useful information on a clinical assessment of MRD.

Survival trade-offs in plant roots during colonization by closely related beneficial and pathogenic fungi

The sessile nature of plants forced them to evolve mechanisms to prioritize their responses to simultaneous stresses, including colonization by microbes or nutrient starvation. Here, we compare the genomes of a beneficial root endophyte, Colletotrichum tofieldiae and its pathogenic relative C. incanum, and examine the transcriptomes of both fungi and their plant host Arabidopsis during phosphate starvation. Although the two species diverged only 8.8 million years ago and have similar gene arsenals, we identify genomic signatures indicative of an evolutionary transition from pathogenic to beneficial lifestyles, including a narrowed repertoire of secreted effector proteins, expanded families of chitin-binding and secondary metabolism-related proteins, and limited activation of pathogenicity-related genes in planta. We show that beneficial responses are prioritized in C. tofieldiae-colonized roots under phosphate-deficient conditions, whereas defense responses are activated under phosphate-sufficient conditions. These immune responses are retained in phosphate-starved roots colonized by pathogenic C. incanum, illustrating the ability of plants to maximize survival in response to conflicting stresses.

Root Endophyte Colletotrichum tofieldiae Confers Plant Fitness Benefits that Are Phosphate Status Dependent

A staggering diversity of endophytic fungi associate with healthy plants in nature, but it is usually unclear whether these represent stochastic encounters or provide host fitness benefits. Although most characterized species of the fungal genus Colletotrichum are destructive pathogens, we show here that C. tofieldiae (Ct) is an endemic endophyte in natural Arabidopsis thaliana populations in central Spain. Colonization by Ct initiates in roots but can also spread systemically into shoots. Ct transfers the macronutrient phosphorus to shoots, promotes plant growth, and increases fertility only under phosphorus-deficient conditions, a nutrient status that might have facilitated the transition from pathogenic to beneficial lifestyles. The host's phosphate starvation response (PSR) system controls Ct root colonization and is needed for plant growth promotion (PGP). PGP also requires PEN2-dependent indole glucosinolate metabolism, a component of innate immune responses, indicating a functional link between innate immunity and the PSR system during beneficial interactions with Ct.

Root Endophyte Colletotrichum tofieldiae Confers Plant Fitness Benefits that Are Phosphate Status Dependent

A staggering diversity of endophytic fungi associate with healthy plants in nature, but it is usually unclear whether these represent stochastic encounters or provide host fitness benefits. Although most characterized species of the fungal genus Colletotrichum are destructive pathogens, we show here that C. tofieldiae (Ct) is an endemic endophyte in natural Arabidopsis thaliana populations in central Spain. Colonization by Ct initiates in roots but can also spread systemically into shoots. Ct transfers the macronutrient phosphorus to shoots, promotes plant growth, and increases fertility only under phosphorus-deficient conditions, a nutrient status that might have facilitated the transition from pathogenic to beneficial lifestyles. The host’s phosphate starvation response (PSR) system controls Ct root colonization and is needed for plant growth promotion (PGP). PGP also requires PEN2-dependent indole glucosinolate metabolism, a component of innate immune responses, indicating a functional link between innate immunity and the PSR system during beneficial interactions with Ct.

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Colletotrichum tofieldiae (Ct) is a fungal root endophyte of Arabidopsis

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Ct transfers the macronutrient phosphorus to Arabidopsis shoots

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Ct-mediated plant growth promotion needs an intact phosphate starvation response

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A branch of the plant innate immune system is essential for beneficial Ct activities

Methods for Long-Term Stable Storage of Colletotrichum Species

In this chapter we describe methods for long-term preservation of ascomycete genus Colletotrichum species. Colletotrichum species employ a hemibiotrophic infection strategy and cause clear anthracnose diseases on various host plants including the model plant Arabidopsis thaliana. Their infection proceeds in a highly synchronized manner, which is helpful for the dissection of the fungus-plant interactions at the molecular level. Gene engineering methods, including efficient protocols for targeted gene disruption, and whole-genome sequences are available for several Colletotrichum species. Thus, these pathogens provide us with model systems to address the molecular mechanisms underlying hemibiotrophic fungal pathogenicity.We describe how to prepare glycerol stocks or filter paper fungal stocks for long-term preservation of Colletotrichum species. These two methods are easily handled, and provide a stable preservation for at least a few years.

Emission behaviour of a series of bimetallic Cd(ii)–Au(i) coordination polymers

CN groups participated in the emission and quenching processes of a series of coordination polymers ([Cd^II(pyridine derivative)₂][Au(CN)₂]₂).

Danger peptide receptor signaling in plants ensures basal immunity upon pathogen-induced depletion of BAK1

Pathogens infect a host by suppressing defense responses induced upon recognition of microbe-associated molecular patterns (MAMPs). Despite this suppression, MAMP receptors mediate basal resistance to limit host susceptibility, via a process that is poorly understood. The Arabidopsis leucine-rich repeat (LRR) receptor kinase BAK1 associates and functions with different cell surface LRR receptors for a wide range of ligands, including MAMPs. We report that BAK1 depletion is linked to defense activation through the endogenous PROPEP peptides (Pep epitopes) and their LRR receptor kinases PEPR1/PEPR2, despite critical defects in MAMP signaling. In bak1-knockout plants, PEPR elicitation results in extensive cell death and the prioritization of salicylate-based defenses over jasmonate-based defenses, in addition to elevated proligand and receptor accumulation. BAK1 disruption stimulates the release of PROPEP3, produced in response to Pep application and during pathogen challenge, and renders PEPRs necessary for basal resistance. These findings are biologically relevant, since specific BAK1 depletion coincides with PEPR-dependent resistance to the fungal pathogen Colletotrichum higginsianum. Thus, the PEPR pathway ensures basal resistance when MAMP-triggered defenses are compromised by BAK1 depletion.

Antibody against chromatin assembly factor-1 is a novel autoantibody specifically recognized in systemic lupus erythematosus

Autoantibodies to proliferating cell nuclear antigen (PCNA) are specifically, if rarely, present in systemic lupus erythematosus (SLE) patient sera. Even SLE patients lacking PCNA reactivity often show reaction to PCNA-binding protein. Here, immunoreactivity to chromatin assembly factor-1 (CAF-1), an essential molecule for DNA replication and a PCNA-binding protein, was compared for the sera of SLE patients, normal healthy controls (NHCs) and other disease controls, and in autoimmune sera reactive to standard autoantigens, by enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence, and immunoblotting. CAF1 and IRF1 expression in SLE and NHC peripheral mononuclear cells were compared by quantitative real-time polymerase chain reaction. Serum interferon-γ-inducing protein-10 and anti-double-stranded (ds)DNA antibody levels were measured by ELISA. Increased CAF-1 autoimmune reactivity was recognized in SLE or serum anti-dsDNA antibody-positive patients. Significantly greater central nervous system (CNS) involvement (aseptic meningitis) and serum anti-dsDNA antibody titers were present more often in anti-CAF-1 antibody-positive than antibody-negative SLE patients. IFN-γ positively regulated CAF-1 expression in vitro and was associated with anti-CAF-1 antibody production in SLE. Thus, a novel anti-CAF-1 autoantibody is frequently found in patients with SLE and is a useful biomarker for diagnosis, especially in cases with CNS involvement. Aberrant IFN-γ regulation appears to play an important role in anti-CAF-1 antibody production in SLE.

The Arabidopsis PEPR pathway couples local and systemic plant immunity

Recognition of microbial challenges leads to enhanced immunity at both the local and systemic levels. In Arabidopsis, EFR and PEPR1/PEPR2 act as the receptor for the bacterial elongation factor EF-Tu (elf18 epitope) and for the endogenous PROPEP-derived Pep epitopes, respectively. The PEPR pathway has been described to mediate defence signalling following microbial recognition. Here we show that PROPEP2/PROPEP3 induction upon pathogen challenges is robust against jasmonate, salicylate, or ethylene dysfunction. Comparative transcriptome profiling between Pep2- and elf18-treated plants points to co-activation of otherwise antagonistic jasmonate- and salicylate-mediated immune branches as a key output of PEPR signalling. Accordingly, as well as basal defences against hemibiotrophic pathogens, systemic immunity is reduced in pepr1 pepr2 plants. Remarkably, PROPEP2/PROPEP3 induction is essentially restricted to the pathogen challenge sites during pathogen-induced systemic immunity. Localized Pep application activates genetically separable jasmonate and salicylate branches in systemic leaves without significant PROPEP2/PROPEP3 induction. Our results suggest that local PEPR activation provides a critical step in connecting local to systemic immunity by reinforcing separate defence signalling pathways.

Pathogen infection trial increases the secretion of proteins localized in the endoplasmic reticulum body of Arabidopsis

Endoplasmic reticulum structures facilitate the increased secretion of proteins during the plant immune response.

Glutathione and tryptophan metabolites are key players in Arabidopsis nonhost resistance against Colletotrichum gloeosporioides

The nonhost resistance of Arabidopsis against hemibiotrophic fungi in the genus Colletotrichum consists of pre- and post-invasive immune responses. Previously, we reported EDR1 and PEN2 as important components of Arabidopsis pre-invasive resistance toward non-adapted Colletotrichum gloeosporioides (Cg). However, despite their defect in entry control pen2 and edr1 mutants terminated further growth of this pathogen by activating the post-invasive hypersensitive response (HR) accompanied by plant cell death. In the present study, we showed that γ-glutamylcysteine synthetase (GSH1), which is required for glutathione biosynthesis, and tryptophan (Trp) metabolism contribute to pre- and post-invasive non-host resistance against Cg. We found GSH1 to be involved in the PEN2-dependent entry control of Cg. Opposite to pen2 and edr1, gsh1 mutants failed to restrict the invasive growth of the pathogen, which demonstrated the requirement for GSH1 during post-invasive non-host resistance. Based on the infection and metabolic phenotypes of Arabidopsis mutants defective in Trp metabolism, we showed that the biosynthesis of Trp-derived phytochemicals is also essential for resistance to Cg during the post-invasive HR. By contrast, GSH1 and these metabolites are dispensable for the induction of HR cell death, which is triggered in the non-invaded mesophyll cells adjacent to the Cg-invaded epidermal cells.

Roles of EDR1 in non-host resistance of Arabidopsis

Entry control of Arabidopsis thaliana against non-adapted powdery mildews largely depends on the PEN1 secretion pathway and the PEN2-PEN3 antifungal metabolite pathway, and is critical for non-host resistance. In a recent study, we reported that ENHANCED DISEASE RESISTANCE 1 (EDR1) plays a role in entry control against a non-adapted anthracnose fungus, which exhibits an infection style distinct from that of powdery mildews. Results obtained using edr1 pen2 double mutants indicate that the contribution of EDR1 to non-host resistance is independent of that of the PEN2-mediated defence pathway. Comparative transcript profiling revealed that EDR1 is critical for expression of four plant defensin genes. The MYC2-encoded transcription factor represses defensin expression. Inactivation of MYC fully restored defensin expression in edr1 mutants, implying that EDR1 cancels MYC2 function to regulate defensin expression. These findings indicate that EDR1 exerts a critical role in non-host resistance, in part by inducing antifungal peptide expression via interference in MYC2-mediated repressor function.

Arabidopsis ENHANCED DISEASE RESISTANCE 1 is required for pathogen-induced expression of plant defensins in nonhost resistance, and acts through interference of MYC2-mediated repressor function

Arabidopsis thaliana exhibits durable resistance, called nonhost resistance, against non-adapted fungal pathogens that typically terminates pathogen entry. The PEN2-dependent indole glucosinolate metabolism pathway is involved in preventing the entry of a range of non-adapted fungi. Here, we report that ENHANCED DISEASE RESISTANCE 1 (EDR1) functions in pre-invasive nonhost resistance. Plants lacking EDR1 exhibit impaired entry resistance to the non-adapted hemibiotrophic Colletotrichum gloeosporioides, in contrast to the enhanced resistance of edr1 against biotrophic infection of a host-adapted powdery mildew fungus. Analysis of the edr1 pen2 double mutant indicates that EDR1 acts in a defense pathway independent from the PEN2 indole glucosinolate pathway. The edr1 mutant also exhibited enhanced susceptibility to host-adapted pathogens, including Colletotrichum higginsianum and necrotrophic Alternaria brassicicola. Comparative transcript profiling revealed that upon C. gloeosporioides inoculation, the expression of four plant defensin genes was severely impaired in edr1, indicating that EDR1 is required for the induced expression of these antifungal proteins. Inactivation of the MYC2-encoded transcription factor fully restored defensin expression in edr1, implying that EDR1 interferes with MYC2 function to abrogate repression of defensin expression. Furthermore, constitutive expression of plant defensin PDF1.2b largely rescued pre-invasive resistance responses in edr1 plants. These results indicate that EDR1 exerts a positive and critical role in resistance responses to hemibiotrophic/necrotrophic fungi, in part by inducing antifungal protein expression through derepression of MYC2 function.

Entry mode-dependent function of an indole glucosinolate pathway in Arabidopsis for nonhost resistance against anthracnose pathogens

When faced with nonadapted fungal pathogens, Arabidopsis thaliana mounts nonhost resistance responses, which typically result in the termination of early pathogenesis steps. We report that nonadapted anthracnose fungi engage two alternative entry modes during pathogenesis on leaves: turgor-mediated invasion beneath melanized appressoria, and a previously undiscovered hyphal tip-based entry (HTE) that is independent of appressorium formation. The frequency of HTE is positively regulated by carbohydrate nutrients and appears to be subject to constitutive inhibition by the fungal mitogen-activated protein kinase (MAPK) cascade of MAPK ESSENTIAL FOR APPRESSORIUM FORMATION1. The same MAPK cascade is essential for appressorium formation. Unexpectedly, the Arabidopsis indole glucosinolate pathway restricts entry of the nonadapted anthracnose fungi only when these pathogens employ HTE. Arabidopsis mutants defective in indole glucosinolate biosynthesis or metabolism support the initiation of postinvasion growth of nonadapted Colletotrichum gloeosporioides and Colletotrichum orbiculare. However, genetic disruption of Colletotrichum appressorium formation does not permit HTE on host plants. Thus, Colletotrichum appressoria play a critical role in the suppression of preinvasion plant defenses, in addition to their previously described role in turgor-mediated plant cell invasion. We also show that HTE is the predominant morphogenetic response of Colletotrichum at wound sites. This implies the existence of a fungal sensing system to trigger appropriate morphogenetic responses during pathogenesis at wound sites and on intact leaf tissue.

126 CRYOPRESERVATION OF PORCINE EMBRYOS DERIVED FROM IVM OOCYTES

We have reported that a combination of delipation (removal of cytoplasmic lipid droplets from blastomeres) and vitrification by means of the minimum-volume cooling (MVC) method successfully cryopreserves porcine in vitro-matured/fertilized (IVM/IVF) embryos, and that normal piglets are produced from these embryos (Hiruma et al. 2006 Reprod. Fertil. Dev. 18, 157). We have also reported that IVM-derived embryos that undergo noninvasive delipation (i.e. micromanipulation is not required) and vitrification develop into blastocysts at a high rate (Esaki et al. 2004 Biol. Reprod. 71, 432–437). In this study, we examined whether fetuses can be produced from the IVM-derived embryos that have been delipated noninvasively and vitrified. Cumulus–oocyte complexes that had been collected from slaughterhouse ovaries were in vitro-matured in NCSU23 medium. The IVM oocytes were activated to produce parthenogenetic embryos. We used the embryos at the 4- to 8-cell (67 h after activation) and morula (98 h) stages in the following experiments. Embryos were treated with 4% trypsin (in PBS) at 38�C for 1 to 4 min to expand the zona pellucida. Next, the embryos were centrifuged (12 000g, 38�C, 23 min) in TL-HEPES-PVP containing 7.5 �g mL-1 cytochalasin B to polarize cytoplasmic lipid droplets within the perivitelline space. These embryos were cultured for 1 to 3 h and then vitrified. The post-thaw viability of the embryos was assessed based on their ability to develop into blastocysts and fetuses (21 to 23 days old). The embryos were vitrified using the MVC method with 15% ethylene glycol, 15% DMSO, and 0.5 M sucrose as cryoprotective agents. PZM-5 was used for culturing the embryos. In embryo transfer experiments, after thawing, the embryos were cultured for 36 or 72 h until they developed into morulae or 4- to 8-cell blastocysts, respectively; they were then treated with 0.5% pronase to remove the zona pellucida, and transferred to the uterine horns of estrus-synchronized recipients 6 days after onset of estrus. The proportion of vitrified embryos that developed into blastocysts and the mean cell number of the blastocysts were similar to those of non-vitrified control embryos, irrespective of the embryonic stage (4- to 8-cell stage: 42.1%, 22/51, 63.0 � 7.8 vs. 64.7%, 22/34, 74.2 � 7.1, respectively; morula stage: 77.6%, 38/49, 69.6 � 7.2 vs. 83.3%, 45/54, 66.2 � 5.9, respectively). Seventeen embryos that had been vitrified at the 4- to 8-cell stage gave rise to 3 fetuses after transfer into one recipient (17.6%). Fifty-three embryos that had been vitrified at the morula stage were transferred into 3 recipients. All recipients became pregnant and produced a total of 17 fetuses (32.1%). These results suggest that porcine IVM-derived embryos that have been cryopreserved by the combination of noninvasive delipation and vitrification by the MVC method are highly viable.

408 FOREIGN GENE INTEGRATION PATTERNS IN TRANSGENIC PORCINE FETUSES PRODUCED BY ICSI-MEDIATED GENE TRANSFER

We previously reported that transgenic (TG) pigs can be produced from in vitro-matured oocytes using intracytoplasmic sperm injection-mediated gene transfer (ICSI-mediated method) (Kurome et al. 2006 Transgenic Res. 15, 229–240). We subsequently studied the expression of a foreign gene which had been introduced by the ICSI-mediated method. We found that the ICSI-mediated method is considerably less likely than the pronuclear microinjection method to produce embryos in which transgene-positive and transgene-negative cells co-exist, that is, mosaic embryos (Saito et al. 2006 Reprod. Fertil. Dev. 18, 297 abst). Therefore, in order to further investigate the ICSI-mediated method, the present study was conducted to address the integration patterns of foreign genes introduced by this method. In particular, we wished to determine the number of transgene copies and number of chromosomal integration sites. TG pig fetuses, obtained by the ICSI-mediated method in a separate cardiac disease model study, were used in the present study. Porcine cumulus-oocyte complexes that had been collected from slaughterhouse ovaries were subjected to in vitro maturation in NCSU23 medium to produce MII oocytes to be used in this study. Porcine spermatozoa frozen in Beltsville Thawing Solution (BTS) were thawed rapidly in a 37�C water bath, and each spermatozoon was decapitated using ultrasound (28 kHz, 100 W; W-113; Honda Electronics Co., Ltd, Aichi, Japan). The heads (2 to 5 � 105/10 �L) were co-incubated with 2.5 ng �L-1 of rabbit calreticulin cDNA (�MHC-CRT-HA: 7.5 kb) for five min at room temperature, and then microinjected into MII oocytes using a piezo-micromanipulator. An electric stimulus (DC 150 V mm-1, 100 �s) was applied 10 to 40 min after microinjection in order to activate the oocytes. The embryos were cultured in PZM-5 medium for one to two days, and then transferred into the oviducts of recipient gilts, whose estrous cycle had been synchronized using 1000 IU eCG and 1500 IU hCG. Fetuses were collected 33 or 50 days later, and a primary cell line (fibroblast) was established. For each fetus, the number of transgene copies was determined by Southern blot. In addition, the chromosomal sites, where the foreign gene had integrated, were identified, and the number of integration sites was determined by fluoresent in situ hybridization (FISH). A total of 454 ICSI embryos were transferred to 4 recipients (92 to 135 embryos/recipient). All recipients became pregnant and 23 fetuses (5.1%, 23/454), including 7 TG fetuses (30.4%, 7/23), were obtained. Southern blot analysis showed that the number of transgene copies varied between 1 and 300 (1 copy: 1 fetus; 10 copies: 2 fetuses; 30 copies: 3 fetuses; 300 copies: 1 fetus). FISH analysis showed that in TG fetuses, the foreign gene had integrated at only a single chromosomal site, and this site varied from TG fetus to TG fetus. These results demonstrate that, in the case of ICSI-mediated gene transfer, as is the case for gene transfer by pronuclear microinjection, the integration patterns are: multiple copy, random site, and single site integration. This study was supported by PROBRAIN.

64 PRODUCTION OF TRANSGENIC CLONED PIGS BY MEANS OF SOMATIC CELL NUCLEAR TRANSFER USING KUSABIRA-ORANGE GENE-TRANSFECTED CELLS

Cloned pigs that express cell markers such as fluorescent proteins (Vintersten et al. 2004 Genesis 40, 241–246) are useful in biomedical research in areas such as cell/tissue transplantation and regenerative medicine. In this study, we attempted to produce transgenic cloned pigs from porcine fetal fibroblasts which carry the gene of red fluorescent protein, humanized Kusabira-Orange (huKO). We examined whether huKO-transfected cells are suitable as nuclear donors for somatic cell cloning, and whether red fluorescence can be detected in the cloned embryos. We used porcine fetal fibroblasts transfected with the huKO gene and a retroviral vector as the nuclear donor cells. Non-transfected cells were used as the control. Cumulus–oocyte complexes collected from slaughterhouse ovaries were in vitro-matured in NCSU23 medium to produce recipient oocytes. Nuclear transfer was conducted using a previously reported method (Kurome et al. 2003 Cloning Stem Cells 5, 367–377); the following parameters which determine the overall efficiency of nuclear transfer were investigated: (1) fusion rate between the donor cells and recipient oocytes, (2) rates of normal cleavage and blastocyst formation of the NT embryos, and (3) cell numbers in each blastocyst. A DC pulse (190 V mm-1) was used for electric fusion, and NCSU23 or PZM-5 medium was used for culturing the cloned embryos. The NT embryos on Day 7 were examined under a fluorescence microscope (G excitation) in order to evaluate the expression of red fluorescence. Some cloned embryos at the 1- to 8-cell stage (Day 1 or 2) were transferred into oviducts of estrus-synchronized recipient gilts. There was no significant difference (chi-square test) between the huKO and the control groups in the rate of fusion (132/151, 87.4% vs. 134/147, 91.2%, respectively) and cleavage rate (78/132, 59.1% vs. 86/134, 64.2%, respectively). A significantly greater percentage of huKO cell-derived embryos developed into blastocysts than did control cell-derived embryos (37/132, 28.0% vs. 20/134, 14.9%, respectively; P < 0.05). However, there was no significant difference in the blastocyst cell numbers (Student's t-test: 48.6 ± 4.8 vs. 42.3 ± 4.9, respectively). Of the 132 NT embryos, 116 (87.9%) expressed red fluorescence. The percentage of blastocysts expressing red fluorescence was 94.6% (35/37). These results demonstrate that it is possible to obtain cloned blastocysts at a high rate by nuclear transfer of cells that have been transfected with huKO using a retroviral vector, and that it is possible to observe the expression of red fluorescence in cloned embryos. With respect to the cloned embryos that did not show expression of red fluorescence, we hypothesize that this was the result of a small proportion (<1%) of donor cells which also lacked red fluorescence expression. An ultrasonic echo examination has confirmed that all 3 of the recipients which had received 93 to 119 embryos became pregnant. This study was supported by PROBRAIN.

Juvenile Hormone Is Required to Couple Imaginal Disc Formation with Nutrition in Insects

In starved larvae of the tobacco hornworm moth Manduca sexta, larval and imaginal tissues stop growing, the former because they lack nutrient-dependent signals but the latter because of suppression by juvenile hormone. Without juvenile hormone, imaginal discs form and grow despite severe starvation. This hormone inhibits the intrinsic signaling needed for disc morphogenesis and does so independently of ecdysteroid action. Starvation and juvenile hormone treatments allowed the separation of intrinsic and nutrient-dependent aspects of disc growth and showed that both aspects must occur during the early phases of disc morphogenesis to ensure normal growth leading to typical-sized adults.

185 EMBRYONIC LOSS IN PIGS ASSOCIATED WITH OVIDUCT TRANSPLANTATION OF EARLY-STAGE EMBRYOS WITH DAMAGES IN THE ZONA PELLUCIDA

It is assumed that if porcine early-stage embryos with damages in their zonae pellucidae are transplanted to the recipient's oviduct, they may suffer from mechanical and immunological stresses by oviduct contraction and the recipient's immune response. This study aimed to examine the impact of zona pellucida damages, which might arise during nuclear transfer and intra cytoplasmic sperm injection (ICSI), on the development and survival of transplanted embryos. Cumulus-oocyte complexes were collected from ovaries obtained at a local slaughterhouse and matured in vitro in NCSU23 to prepare MII-stage oocytes. The zonae pellucidae of these oocytes were either penetrated with 8- to 10-�m square-ended microinjection pipettes or incised with 35- to 40-�m beveled enucleation pipettes. Intact oocytes were used as controls. The oocytes were electroactivated to induce parthenogenesis and transplanted to the oviducts of estrus-synchronized recipient gilts (estrus-synchronized with 1000 IU eCG and 1500 IU hCG). After 5 to 7 days, the recipient uteri were flushed with PBS supplemented with 1% fetal bovine serum (FBS) to collect embryos, and their development (morula-blastocyst stage embryos/collected embryos) and survival (viable embryos/collected embryos) were determined. In total, 221 zona-penetrated, 129 zona-incised, and 57 intact embryos were transplanted to four, two and two gilts, respectively. The efficiency of embryo recovery was similar in all groups (59.0 to 81.8%). However, the zona-penetrated and zona-incised embryos showed inconsistent development and survival compared with controls; the development and survival rate were 92.6% (25/27) to 96.7% (29/30) and 77.8% (21/27) to 96.7% (29/30) in control embryos, respectively, whereas those of zona-penetrated embryos were 57.1% (28/49) to 95.7% (22/23) and 8.2% (4/49) to 78.3% (18/30), and those of zona-incised embryos were 47.6% (30/63) to 92.3% (36/39) and 23.8% (15/63) to 92.3% (22/23), respectively. Large foci of cells that appeared to be macrophage giant cells were observed at the surface or inside of the degenerated zona-damaged embryos. These results indicate that the recipient's immune response may impair development after transplantation of the embryo to the oviduct, when there is damage in the zona pellucida. This may be one of the factors attributable to the reduced efficiency of live progeny production by ICSI and nuclear transfer. This work was supported by PROBRAIN.

98 SUCCESSFUL PREGNANCIES FOLLOWING TRANSFER OF VITRIFIED PORCINE EMBRYOS DERIVED FROM IN VITRO-MATURED OOCYTES

To date only in vivo-produced embryos have successfully produced live piglets after cryopreservation. In this study, we aimed to produce piglets from vitrified embryos derived from in vitro matured (IVM) oocytes. Cumulus-oocyte complexes collected from ovaries obtained at a local slaughterhouse were matured for 44 to 45 h in NCSU23 MEDIUM supplemented with 0.6 mM cysteine, 10 ng/mL epidermal growth factor, 10% (v/v) porcine follicular fluid, 75 �g/mL potassium penicillin G, 50 �g/mL streptomycin sulfate, and 10 IU/mL eCG/ hCG. These IVM oocytes were either activated for parthenogenesis or in vitro-fertilized (IVF). For IVF, oocytes were incubated with 5 � 106/mL of cryopreserved epididymal sperm in PGM-tac medium (Yoshioka et al. 2003 Biol. Reprod. 69, 2092-2099) for 20 h. Embryos were treated for removal of cytoplasmic lipid droplets (delipation; Nagashima et al. 1995 Nature 374, 416) at the 4- to 8-cell stages, around 50 to 54 h after activation or insemination. After culture in NCSU23 for 15 h, they were vitrified by the minimum volume cooling (MVC) method. Embryos were equilibrated with equilibration solution containing 7.5% (v/v) ethylene glycol (EG), 7.5% (v/v) dimethylsulfoxide (DMSO), and 20% (v/v) calf serum for 4 min, followed by exposure to vitrification solution containing 15% EG, 15% DMSO, 0.5 M sucrose, and 20% calf serum. Embryos were then loaded onto a Cryotop (Kitazato Supply Co., Tokyo, Japan) and immediately plunged into liquid nitrogen. Vitrified embryos were examined for viability in vitro and in vivo after warming. Their in vitro developmental competence was compared to that of corresponding control (nonvitrified) embryos. Vitrified 4- to 8-cell stage embryos, both parthenogenetic and IVF, showed developmental competence into blastocysts comparable to that of control embryos (parthenogenetic: 46.8%, 36/77 vs. 51.7%, 31/60; IVF: 40.0%, 30/75 vs. 44.3%, 35/79). Of four surrogate gilts that received a total of 251 vitrified parthenogenetic embryos, three became pregnant and had 20 fetuses (8.0%, 22 to 23 days old). Three surrogates gilts that received 267 vitrified IVF embryos all became pregnant. Of those, the one that received 47 embryos was confirmed to have eight fetuses (17.0%, 22 days old) by autopsy. The other two were examined by ultrasonography at 56 and 95 days of gestation and found to be pregnant. These results suggest that porcine embryos derived from IVM oocytes have a potential to develop into live offspring after delipation and MVC vitrification. This study was supported by PROBRAIN.

380 COMPARISON OF TRANSGENE EXPRESSIONS BY ICSI AND PRONUCLEAR MICROINJECTION IN MURINE AND PORCINE EMBRYOS

Intracytoplasmic sperm injection (ICSI) of DNA-binding sperm produces transgenic offspring as effectively as pronuclear microinjection (PNM). A significant difference in these two methods is that DNA is introduced into MII oocytes during ICSI, which is likely to allow earlier gene integration compared to PNM. This leads us to hypothesize that ICSI reduces the chance of development of a mosaic embryo, a mixture of transgene-positive and -negative cells. To test this hypothesis, we compared expression patterns of the green flourescent protein (GFP) gene introduced by ICSI and PNM into murine and porcine oocytes. For ICSI, 2 to 5 × 105/μL of sperm frozen-thawed in CZB (for mice) or NIM (for pigs) were co-incubated with 2.5 ng/μL of transgene fragments (CAG-EGFP; 3 kb) for 5 min. Murine sperm were microinjected into in vivo-matured oocytes, and porcine sperm into in vitro-matured oocytes. PNM was performed by microinjection of several picoliters of the transgene fragments (10 ng/μL) into pronuclei of in vivo-fertilized oocytes for mice and in vitro-matured and -fertilized oocytes for pigs. ICSI and PNM embryos were cultured in vitro to the morula stage and treated with 0.5% pronase to remove the zona pellucida. These morulae were disassembled into individual blastomeres by pipetting into PBS containing 100 μM EDTA and examined for GFP expression under fluorescence microscopy. As shown in Table 1, the rate of mosaicism in GFP-expressing embryos was significantly lower for ICSI than for PNM (P < 0.01). In addition, GFP-expressing ICSI embryos were likely to contain high percentages, 81 to 100%, of GFP-positive cells, whereas GFP-expressing PNM embryos were significantly less likely to contain such high percentages of GFP-positive cells (P < 0.01). From these results, we conclude that transgenesis by ICSI was less likely to produce mosaic embryos, and that produced transgenic embryos contained higher proportions of transgene-positive cells, although genomic integration remains to be determined. Table 1. Transgene expression by ICSI and pronuclear microinjection in murine and porcine embryos This work was supported by PROBRAIN.

50 PRODUCTION OF THIRD-GENERATION CLONES OF A PIG BY SOMATIC CELL NUCLEAR TRANSFER

There has been a dominant view that serial cloning, i.e., cloning of a cloned animal, is only possible for a few generations. In this study, we examined the reproduction efficiency and normality of porcine offspring generated by serial somatic cell cloning. Salivary gland progenitor (SGP) cells were collected from a 4-month-old female cloned Landrace large white Duroc (LWD) pig (first generation, G1), which had been cloned from a fibroblast, and used as nuclear donors for second-generation clones (G2). The third generation of clones (G3) was produced by nuclear transfer using SGP cells from the G2 clones. Nuclear transfer was carried out by electric cell fusion using in vitro matured oocytes as recipients. Reconstructed embryos were electroactivated 1 to 1.5 hr after nuclear transfer, cultured for 1 to 2 days, and transplanted to the oviducts of estrus-synchronized surrogate gilts. A total of 391 embryos cloned from G1 animals were transplanted to three surrogates. All of the surrogates became pregnant and gave birth to a total of 13 (3.3%) of G2 clones (including two stillbirths). The average birth weight and size of eleven live piglets were 1203.6 � 113.5 g and 27.1 � 1.2 cm, both within the standard ranges of the original donor strain (LWD). Their growths until 8 months old were comparable to those of normal piglets of the same strain. For the generation of G3 clones, transplantation of 242 G2-derived embryos to two surrogate gilts resulted in one pregnant surrogate and three G3 clones (1.2%; average weight 1196.7 � 267.1 g and average size 35.7 � 2.3 cm), including a stillbirth. These results indicate that porcine serial cloning can efficiently generate up to three generations of apparently healthy clones, when SGP cells are used as nuclear donors. This study was supported by PROBRAIN.

Recovery of Valpha24+ NKT cells after hematopoietic stem cell transplantation

Human Valpha24+ natural killer T (NKT) cells have an invariant T-cell receptor-alpha chain and are activated in a CD1d-restricted manner. Valpha24+ NKT cells are thought to regulate immune responses and to play important roles in the induction of allograft tolerance. In this report, we analyzed the recovery of Valpha24+ NKT cells after hematopoietic stem cell transplantation and its correlation with graft-versus-host disease (GVHD). Patients who received a dose-reduced conditioning regimen, antithymocyte globulin- or CAMPATH-1H-containing conditioning regimen were excluded. NKT cells were reconstituted within 1 month after transplantation in peripheral blood stem cell transplantation recipients, while their numbers remained low for more than 1 year in bone marrow transplantation (BMT) recipients. The number of Valpha24+ NKT cells in BMT recipients with acute GVHD was lower than that in patients without acute GVHD, and both the CD4+ and CD4- Valpha24+ NKT subsets were significantly reduced. With regard to chronic GVHD, BMT recipients with extensive GVHD had significantly fewer Valpha24+ NKT cells than other patients. Furthermore, the number of CD4+ Valpha24+ NKT cells was also significantly reduced in patients with chronic extensive GVHD. Our results raise the possibility that the number of Valpha24+ NKT cells could be related to the development of GVHD.

69 PRODUCTION OF CLONED PIGS BY NUCLEAR TRANSFER OF PREADIPOCYTES

Since the first success in producing cloned pigs, donor cells have been limited to fetal fibroblasts and a few other cell types. The aim of the present study was to determine if porcine preadipocytes can be efficient donor cells for somatic cell nuclear transfer (NT) in pigs. Preadipocytes established from subcutaneous adipose tissue of a male adult pig were used as nuclear donor cells. Cell cycle synchronization was carried out by serum starvation (5 days), confluency (5 days), roscovitine treatment (15 μM, 2 days), or differentiation induction by 0.5 mM 3-Isobutyl-1-methylxanthine, 0.25 μM dexamethasone, and 5 μg/mL insulin (5 days). Cell cycle synchronization and apoptosis of the donor cells were examined by flow cytometry and Annexin V staining and TUNEL. IVM oocytes were obtained from abattoir ovaries and matured in NCSU23. Donor cells were fused with the enucleated recipient oocytes by a single DC pulse of 200 V/mm for 10 μs in 0.28 M mannitol + 0.15 mM MgSO4. Reconstructed embryos were electrically activated at 1–1.5 h after the NT, followed by cytochalasin B treatment for 3 h. Development of the NT embryos was assessed by fixation/staining at 3 h after NT, culture for 7 days in NCSU23, and transfer to the oviducts of estrus-synchronized recipient gilts. The cells immediately entered the G0 phase by differentiation induction (92.5 ± 0.4%), with higher efficiency of synchronization than for the other methods (roscovitine: 80.3 ± 0.2%; confluency: 79.9 ± 0.3%, P < 0.05) except for serum starvation (89.8 ± 0.6%). The proportion of apoptotic cells in the differentiation group was significantly lower than the other groups (Annexin V: 7.7% vs. 15.7 to 19.3%, TUNEL: 8.3% vs. 12.8 to 14.0%, P < 0.05). Incidence of premature chromosome condensation following NT (88.0%) was as high as that observed after NT with fetal fibroblasts previously (data not shown). In vitro developmental rates of the NT embryos did not differ significantly among the cell cycle synchronization methods of the donor cells (7.2 to 10.8%). Cell number of the blastocysts was highest in the differentiation group (49.0 vs. 30.2 to 41.9, P < 0.05). Transfer of 1004 cloned embryos of the serum starvation group to 5 recipients resulted in the production of 4 live and 1 stillborn piglets from 1 recipient. Transfer of cloned embryos reconstructed of donor cells treated by differentiation induction is currently underway. These data demonstrate that preadipocytes collected from an adult pig are promising nuclear donor cells for pig cloning. This study was supported by PROBRAIN.

Clinical features and treatment of hematopoietic stem cell transplantation-associated gastric antral vascular ectasia

Gastric antral vascular ectasia (GAVE) may occur after hematopoietic stem cell transplantation (HSCT) and cause severe and prolonged gastric bleeding. The underlying pathology of transplant-associated GAVE (HSCT-GAVE) is poorly understood and an effective therapeutic strategy has not been established yet. We retrospectively reviewed the medical records of 230 consecutive allogeneic transplant recipients in our institution between January 1997 and June 2002. We identified five patients who developed HSCT-GAVE (2.2%). Four patients had bleeding from HSCT-GAVE and one patient had HSCT-GAVE discovered incidentally. The clinical features of these patients were similar in that they all received conditioning treatment with busulfan and had history of thrombotic microangiopathy. Furthermore, treatment with a beta-blocker apparently improved the outcome of HSCT-GAVE in three patients.

Regression of an unresectable pancreatic tumor following nonmyeloablative allogeneic peripheral-blood stem-cell transplantation

A 59-year-old female with an unresectable, large pancreatic tumor (10.0 x 8.0 cm(2) on CT scan) underwent nonmyeloablative allogeneic peripheral-blood stem-cell transplantation from her HLA-identical sibling. Pronounced tumor regression and relief from pain without acute graft-versus-host disease (GVHD) were observed following transplantation. The patient is surviving (more than 300 days) after transplantation, with extensive chronic GVHD, and has tumor regression with an 80% reduction in tumor size. The observed clinical course may suggest a graft-versus-tumor effect on the pancreatic tumor following allogeneic stem-cell transplantation.

Isolation and characterization of a dopa decarboxylase cDNA and the induction of its expression by an insect cytokine, growth-blocking peptide in Pseudaletia separata

Parasitization by the wasp, Cotesia kariyai, elevates the concentration of an insect cytokine, growth-blocking peptide (GBP), in hemolymph of last instar Pseudaletis separata larvae. The increase of epidermal and hemolymph dopamine level is associated with the GBP increase. Both GBP and dopamine disturb host development and metamorphosis (Hayakawa, 1995). Dopa decarboxylase (DDC) converts Dopa to dopamine, and its cDNA was isolated from P. separata, and the deduced amino acid sequence showed that it was highly homologous to other lepidopteran DDCs, showing 96, 90 and 86% identity with those of Mamestra brassicae, Bombyx mori, and Manduca sexta, respectively. A 3.2 kb DDC mRNA transcript was constitutively expressed at low levels in the epidermis, brain-nerve cord and hemocytes, and the expression was enhanced by injection of GBP in these tissues. Detailed characterization of the DDC mRNA expression in the epidermis showed that its expression reached a plateau 3 hr after the injection. DDC activity and DDC protein (55 kDa) level mirrored the mRNA expression. Immunocytochemistry with anti-DDC antibody confirmed that the enhanced DDC expression was localized in the epidermal cells. Dopamine concentration in the epidermis gradually increased and reached maximum 6 hr after the injection. When the epidermis of Day 1 last instar larvae was cultured in vitro in the presence of GBP, DDC mRNA increased, indicating that GBP acted on the epidermal cells directly to induce expression of the DDC gene.

Hepatitis B virus reactivation in a patient with chronic GVHD after allogeneic peripheral blood stem cell transplantation

We report a patient with fatal hepatitis B virus (HBV) reactivation after treatment for chronic graft-versus-host disease (GVHD) following allogeneic peripheral blood stem cell transplantation to treat chronic myelogenous leukemia. The presence of antibodies to hepatitis B surface antigen (HBsAb) prior to transplantation indicated previous HBV infection. Liver damage first developed 8 months after transplantation with the disappearance of HBsAb. Hepatitis B antigen was first noted during an examination of liver damage that occurred 22 months after transplantation. Retrospective examination of serum by real-time detection polymerase chain reaction (RTD-PCR) revealed HBV in both the first and second episodes of liver damage (89 copies/mL and 2 x 10(6) copies/mL, respectively). HBV may have been reactivated, leading to fatal liver damage in this HBsAb-positive patient. We propose that RTD-PCR-based analysis should be performed to diagnose liver dysfunction after hematopoietic stem cell transplantation.

Acquired storage-pool disorders occurring late after allogeneic bone marrow transplantation: partial activation of platelets in asymptomatic patients

Bone marrow transplantation (BMT) may be complicated by coagulation abnormalities. The present study evaluated whether platelets might be activated in patients who had undergone BMT without significant coagulopathy. The patients selected had received allogeneic BMTs a median of 39 months before the study (range, 11-124 months) and had not received cyclosporine, FK506 (tacrolimus), or other medication affecting cyclo-oxygenase for at least 3 months prior to the collection of blood samples. Furthermore, patients had platelet counts greater than 100 x 10(9) cells/L and normal serum creatinine levels. Twenty-five healthy volunteers acted as controls. Platelet aggregation studies and a mepacrine assay of platelets showed abnormal aggregation and decreased staining in some patients. The platelet storage-pool adenosine 5'-triphosphate (ATP) level in 15 patients after BMT was 0.45+/-0.24 micromol per 10(11) platelets, whereas the level in 18 controls was 1.03+/-0.36 micromol per 10(11) platelets (P = .00078). The total ATP levels of platelets in patients and controls were 4.33+/-1.14 and 5.63+/-1.51 micromol per 10(11) platelets, respectively (P = .016). With the exception of 1 patient, plasma levels of thrombomodulin and von Willebrand factor were all within the normal range. The average plasma level of 11-dehydrothromboxane B2 was significantly increased in 15 patients after BMT compared with controls, 20.6+/-8.2 and 10.3+/-1.2 pg/mL, respectively (P = .0004). These findings suggest a long-term process of platelet activation in patients after BMT and, following the cessation of cyclosporine, development of acquired storage-pool disorder of platelets.

Isolation and developmental expression of two nuclear receptors, MHR4 and betaFTZ-F1, in the tobacco hornworm, Manduca sexta

The cDNAs for two members of the nuclear receptor superfamily were isolated from the tobacco hornworm, Manduca sexta. The deduced amino acid sequence of MHR4 shows 93-95% identity in the DNA-binding domain and the first portion of the hinge (D) region with the germ cell nuclear factor (GCNF)-related factors (GRFs) of the silkworm, Bombyx mori, and the mealworm, Tenebrio molitor, and with a genomic sequence from the fruit fly, Drosophila melanogaster. Northern blot hybridization showed that a 7.5 kb MHR4 mRNA appeared in Manduca abdominal epidermis just as the ecdysteroid titer began to decline during the larval molt, disappeared about 12 h later, then transiently reappeared shortly before larval ecdysis. During the pupal and adult molts, a similar pattern of expression was seen (the very end of the adult molt was not studied). At peak times of expression in the epidermis, MHR4 mRNA was also present in fat body and the central nervous system (CNS). The deduced amino acid sequence of Manduca FTZ-F1 is 100% and 96% identical to that of B. mori and Drosophila betaFTZ-F1, respectively, in the DNA-binding domain and the adjacent hinge region including the FTZ-F1 box. Northern blot analysis showed that the >9.5 kb betaFTZ-F1 mRNA appeared in Manduca epidermis during the decline of the ecdysteroid titer in the larval, pupal and adult molts as the first peak of MHR4 mRNA declined, then it disappeared in the larval and pupal molts before the second peak of MHR4 appeared. betaFTZ-F1 mRNA was also found in fat body and the CNS at the time of peak expression in the epidermis during the larval and pupal molts. Both MHR4 and betaFTZ-F1 mRNAs were found in the testis during the onset of spermatogenesis in the prepupal period.

Second allogeneic peripheral blood stem cell transplantation with fludarabine-based low-intensity conditioning regimen for relapsed myelodysplastic syndrome after allogeneic bone marrow transplantation

We describe the case of a 51-year-old patient with relapsed myelodysplastic syndrome after allogeneic bone marrow transplantation (BMT), who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) after conditioning with a novel regimen consisting of fludarabine, busulfan, and antithymocyte globulin. The second PBSCT was performed early, at 3 months after the initial allogeneic BMT, but it was well tolerated and complete hematologic remission was documented. The patient did not experience any early transplantation-related organ toxicity but died from opportunistic infection 6 months after the second transplantation. Our experience suggests that this novel regimen may induce remission and could be offered to patients relapsing after the first transplantation; however, the fludarabine-containing regimen might be accompanied by profound immunosuppression.

Regulation of transcription factors MHR4 and betaFTZ-F1 by 20-hydroxyecdysone during a larval molt in the tobacco hornworm, Manduca sexta

During the last larval molt in Manduca sexta, a number of transcription factors are sequentially expressed. Unlike E75A and MHR3, whose mRNAs are induced when the ecdysteroid titer increases, the expression of MHR4 mRNA occurs transiently at the onset of the decline of ecdysteroid titer followed by betaFTZ-F1 mRNA expression when the ecdysteroid titer becomes low. When day 2 fourth epidermis was exposed to 20-hydroxyecdysone (20E) in vitro, MHR4 mRNA appeared between 12 and 21 h, peaked at 24 h, and then declined. Using the protein synthesis inhibitors cycloheximide and anisomycin both in vivo and in vitro, we found that the MHR4 transcript was directly induced by 20E and required the presence of 20E for its expression. The accumulation of MHR4 mRNA, however, did not occur until a 20E-induced inhibitory protein(s) disappeared. This control of MHR4 expression is unique among the ecdysone-induced transcription factors. When the epidermis was cultured with 20E, betaFTZ-F1 mRNA was not induced until after the removal of 20E as previously found for Drosophila and the silkworm Bombyx mori. The presence of juvenile hormone had no effect on accumulation of either transcript.

Effect of leucocyte reduction on the potential alloimmunogenicity of leucocytes in fresh-frozen plasma products

BACKGROUND AND OBJECTIVES

Adverse effects mediated by leucocytes in cellular blood products are widely recognized. There are few studies, however, concerning the effects of residual leucocytes in fresh-frozen plasma (FFP). We examined the quantities and characteristics of leucocytes in FFP in order to investigate the potential leucocyte-associated adverse effects of FFP transfusion, focusing on the risk of alloimmunization.

MATERIALS AND METHODS

The quantity of leucocytes in FFP was estimated by using the Nageotte method and flow cytometry (FCM) analysis. The viability and subsets of leucocytes were determined by FCM using propidium iodide (PI) and fluorescein-conjugated antibodies. To investigate alloimmunogenicity caused by the leucocytes in FFP, mixed lymphocyte cultures (MLC) were performed using fresh, allogeneic peripheral blood mononuclear cells (PBMCs) as responder cells and cell-concentrated thawed FFP as a stimulator. We also studied the performance of leucocyte-reduction filters with FFP products.

RESULTS

The average number of leucocytes in a single unit of FFP, derived from 200 ml of whole blood, was 2.98 x 10(6) (range 0.99-8.38 x 10(6)). The majority of these cells were PI-positive dead cells; however, a small but consistent population of PI-negative cells was present in these products. Both dead and live cells expressed human leucocyte antigen (HLA) class I antigens, and approximately 38% of these cells expressed HLA class II antigens. The average number of viable CD3+ T cells in one unit of FFP was 2.36 x 10(4). Growth of the allogeneic PBMCs increased following stimulation with highly concentrated FFP. Use of leucocyte-reduction filters significantly reduced the concentrations of both PI-positive (dead) and PI-negative (live) cells. The growth of allogeneic lymphocytes after stimulation with FFP was also completely suppressed by leucocyte filtration of FFP.

CONCLUSION

Transfusion of FFP is potentially alloimmunogenic owing to its residual leucocyte content. Leucocyte-reduction filters appear to be effective in suppressing the alloimmunogenicity of FFP.

Patterns of MHR3 expression in the epidermis during a larval molt of the tobacco hornworm Manduca sexta

MHR3, an ecdysone-induced transcription factor, was shown to appear in the abdominal epidermis of the tobacco hornworm Manduca sexta in a pattern-specific manner as the 20-hydroxyecdysone (20E) titer rises for the larval molt. The crochet epidermis that forms the hooked setae on the proleg is first to show MHR3 mRNA and protein followed sequentially by the spiracle, the dorsal intrasegmental annuli, the interannular regions, and finally the trichogen and tormogen cells. The protein appears in the nuclei about 8 h before the onset of cuticle formation, is present during the outgrowth of the setae, and disappears after epicuticle formation. In vitro studies showed that MHR3 mRNA induction in the crochet epidermis by 20E was more sensitive (EC(50) = 10(-6) M; 50% induction by 2 h exposure to 4 x 10(-6) M 20E) and did not require protein synthesis for maximal accumulation compared to the dorsal epidermis. The ecdysone receptor complex is present in both tissues at the outset of the molt and therefore is not a determining factor in these responses. Thus, in addition to the ecdysone receptor complex, region-specific factors govern both sensitivity and timing of responsiveness of MHR3 to 20E to ensure that this transcription factor will be present when needed for its differentiative role.