New molecular bridge between RelA/p65 and NF-κB target genes via histone acetyltransferase TIP60 cofactor

The nuclear factor-κB (NF-κB) family is involved in the expressions of numerous genes, in development, apoptosis, inflammatory responses, and oncogenesis. In this study we identified four NF-κB target genes that are modulated by TIP60. We also found that TIP60 interacts with the NF-κB RelA/p65 subunit and increases its transcriptional activity through protein-protein interaction. Although TIP60 binds with RelA/p65 using its histone acetyltransferase domain, TIP60 does not directly acetylate RelA/p65. However, TIP60 maintained acetylated Lys-310 RelA/p65 levels in the TNF-α-dependent NF-κB signaling pathway. In chromatin immunoprecipitation assay, TIP60 was primarily recruited to the IL-6, IL-8, C-IAP1, and XIAP promoters in TNF-α stimulation followed by acetylation of histones H3 and H4. Chromatin remodeling by TIP60 involved the sequential recruitment of acetyl-Lys-310 RelA/p65 to its target gene promoters. Furthermore, we showed that up-regulated TIP60 expression was correlated with acetyl-Lys-310 RelA/p65 expressions in hepatocarcinoma tissues. Taken together these results suggest that TIP60 is involved in the NF-κB pathway through protein interaction with RelA/p65 and that it modulates the transcriptional activity of RelA/p65 in NF-κB-dependent gene expression.

Blood donors on teratogenic drugs and donor deferral periods in a clinical situation

Deferral of blood donors taking teratogenic drugs is critical. From March 2008 to January 2009, we analysed stored blood specimens from donors who had taken teratogenic drugs and whose blood was transfused to women of childbearing age to determine the plasma concentration at the time of donation using high-performance liquid chromatography. In total, 167 specimens were examined. The numbers of specimens exceeding the quantification limit were 7, 39, 4, 2 and 1 for finasteride, isotretinoin, acitretin, etretinate and dutasteride, respectively. Finasteride was beyond the recommended drug deferral period in one specimen. These results may help create practical deferral policies.

Cryobanking of Korean allium germplasm collections: results from a 10 year experience

This paper reviews a 10-year experience in establishing a cryopreserved Allium germplasm collection at the genebank of the National Agrobiodiversity Center, Republic of Korea. A systematic approach to Allium cryopreservation included: 1. revealing the most critical factors that affected regeneration after cryostorage; 2. understanding the mechanisms of cryoprotection by analyzing the thermal behavior of explants and cryoprotectant solutions using DSC and influx/efflux of cryoprotectants using HPLC; 3. assessing genetic stability of regenerants; and 4. revealing the efficiency of cryotherapy. Bulbil primordia, i.e. asexual bulbs formed on unripe inflorescences, proved to be the most suitable material for conservation of bolting varieties due to high post-cryopreservation regrowth and lower microbial infection level, followed by apical shoot apices from single bulbs and cloves. A total of 1,158 accessions of garlic as well as some Allium species have been cryopreserved during 2005-2010 using the droplet-vitrification technique with a mean regeneration percentage of 65.9 percent after cryostorage. These results open the door for large-scale implementation of cryostorage and for simplifying international exchange for clonal Allium germplasm.

In vivo quantitative evaluation of the transport kinetics of gold nanocages in a lymphatic system by noninvasive photoacoustic tomography

Sentinel lymph node (SLN) biopsy has emerged as a preferred method for axillary lymph node staging of breast cancer, and imaging the SLN in three-dimensional space is a prerequisite for the biopsy. Conventional SLN mapping techniques based on the injection of an organic dye or a suspension of radioactive colloids suffer from invasive surgical operation for visual detection of the dye or hazardous radioactive components and low spatial resolution of Geiger counters in detecting the radioactive colloids. This work systematically investigates the use of gold nanocages (AuNCs) as a novel class of optical tracers for noninvasive SLN imaging by photoacoustic (PA) tomography in a rat model. The transport of AuNCs in a lymphatic system and uptake by the SLN were evaluated by PA tomography on the axillary region of a rat. Quantification of AuNCs accumulated in the lymph node was achieved by correlating the data from PA imaging with the results from inductively coupled plasma mass spectrometry. Several parameters were systematically evaluated and optimized, including the concentration, size, and surface charge of the AuNCs. These results are critical to the further development of this AuNC-based PA tomography system for noninvasive SLN imaging, providing valuable information for metastatic cancer staging.

Production of human papillomavirus type 33 L1 major capsid protein and virus-like particles from Bacillus subtilis to develop a prophylactic vaccine against cervical cancer

We developed a bacterial expression system to produce human papillomavirus (HPV) type 33 L1 major capsid protein and virus-like particles from a recombinant Bacillus subtilis strain. For the first time, we have isolated self-assembled virus-like particles (VLPs) of HPV type 33 from B. subtilis, a strain generally recognized as safe (GRAS). The gene encoding the major capsid protein L1 of HPV type 33 was amplified from viral DNA isolated from a Korean patient and expressed in B. subtilis; a xylose-induction system was used to control gene activity. HPV33 L1 protein was partially purified by 40% (w/v) sucrose cushion centrifugation and strong cation exchange column chromatography. Eluted samples exhibited immunosignaling in fractions of 0.5-1.0 M NaCl. The HPV33 L1 protein was shown to be approximately 56 kDa in size by SDS-PAGE and Western blotting; recovery and purity were quantified by indirect immuno-ELISA assay. The final yield and purity were approximately 20.4% and 10.3%, respectively. Transmission electron microscopic analysis of fractions immunoactive by ELISA revealed that the L1 protein formed self-assembled VLPs with a diameter of approximately 20-40 nm. Humoral and cellular immune responses provoked by the B. subtilis/HPV33 L1 strain were approximately 100- and 3-fold higher than those of the empty B. subtilis strain as a negative control, respectively. Development of a VLP production and delivery system using B. subtilis will be helpful, in that the vaccine may be convenient production as an antigen delivery system. VLPs thus produced will be safer for human use than those purified from Gram-negative strains such as Escherichia coli. Also, use of B. subtilis as a host may aid in the development of either live or whole cell vaccines administered by antigen delivery system.

Tip60 regulates myoblast differentiation by enhancing the transcriptional activity of MyoD via their physical interactions

The progression of muscle differentiation is tightly controlled by multiple groups of transcription factors and transcriptional coregulators. MyoD is a transcription factor of the myogenic basic helix-loop-helix family required for the process of muscle cell differentiation. We now show that Tip60 is required for myoblast differentiation via enhancement of the transcriptional activity of MyoD. Knockdown of Tip60 in C2C12 cells leads to a lack of ability to switch from proliferating myoblasts to differentiated myotubes. Ectopic expression of Tip60 increased MyoD-mediated luciferase activity on the myogenic regulatory gene, myogenin. We also found that Tip60 physically interacts with MyoD using its chromo- and Zn-finger-containing region, and that these protein interactions were required for the effective transcriptional activation of MyoD. Furthermore, a chromatin immunoprecipitation assay revealed that Tip60 recruits MyoD on the myogenin promoter, and Tip60 also increases the levels of acetylated histones H3 and H4 during myogenic differentiation. Taken together, these findings suggest that Tip60 is an important co-activator for MyoD-mediated myogenesis in mouse myoblast C2C12 cells.

The bone marrow-expressed antimicrobial cationic peptide LL-37 enhances the responsiveness of hematopoietic stem progenitor cells to an SDF-1 gradient and accelerates their engraftment after transplantation

We report that the bone marrow (BM) stroma-released LL-37, a member of the cathelicidin family of antimicrobial peptides, primes/increases the responsiveness of murine and human hematopoietic stem/progenitor cells (HSPCs) to an α-chemokine stromal-derived factor-1 (SDF-1) gradient. Accordingly, LL-37 is upregulated in irradiated BM cells and enhances the chemotactic responsiveness of hematopoietic progenitors from all lineages to a low physiological SDF-1 gradient as well as increasing their (i) adhesiveness, (ii) SDF-1-mediated actin polymerization and (iii) MAPK(p42/44) phosphorylation. Mice transplanted with BM cells ex vivo primed by LL-37 showed accelerated recovery of platelet and neutrophil counts by ∼3-5 days compared with mice transplanted with unprimed control cells. These priming effects were not mediated by LL-37 binding to its receptor and depended instead on the incorporation of the CXCR4 receptor into membrane lipid rafts. We propose that LL-37, which has primarily antimicrobial functions and is harmless to mammalian cells, could be clinically applied to accelerate engraftment as an ex vivo priming agent for transplanted human HSPCs. This novel approach would be particularly important in cord blood transplantations, where the number of HSCs available is usually limited.

Gelsolin negatively regulates the activity of tumor suppressor p53 through their physical interaction in hepatocarcinoma HepG2 cells

As a transcription factor, p53 modulates several cellular responses including cell-cycle control, apoptosis, and differentiation. In this study, we have shown that an actin regulatory protein, gelsolin (GSN), can physically interact with p53. The nuclear localization of p53 is inhibited by GSN overexpression in hepatocarcinoma HepG2 cells. Additionally, we demonstrate that GSN negatively regulates p53-dependent transcriptional activity of a reporter construct, driven by the p21-promoter. Furthermore, p53-mediated apoptosis was repressed in GSN-transfected HepG2 cells. Taken together, these results suggest that GSN binds to p53 and this interaction leads to the inhibition of p53-induced apoptosis by anchoring of p53 in the cytoplasm in HepG2 cells.

Conditioning for hematopoietic transplantation activates the complement cascade and induces a proteolytic environment in bone marrow: a novel role for bioactive lipids and soluble C5b-C9 as homing factors

We have observed that conditioning for hematopoietic transplantation by lethal irradiation induces a proteolytic microenvironment in the bone marrow (BM) that activates the complement cascade (CC). As a result, BM is enriched for proteolytic enzymes and the soluble form of the terminal product of CC activation, the membrane attack complex C5b-C9 (MAC). At the same time, proteolytic enzymes induced in irradiated BM impair the chemotactic activity of α-chemokine stromal-derived factor-1 (SDF-1). As SDF-1 is considered a crucial BM chemoattractant for transplanted hematopoietic stem/progenitor cells (HSPCs), we sought to determine whether other factors that are resistant to proteolytic enzymes have a role in this process, focusing on proteolysis-resistant bioactive lipids. We found that the concentrations of sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) increase in the BM after conditioning for transplantation and that both S1P and, as we show here for the first time, C1P are potent chemoattractants for HSPCs. Next, we observed that C5-deficient mice that do not generate MAC show impaired engraftment of HSPCs. In support of a role for MAC in homing and engraftment, we found that soluble MAC enhances in a CR3 (CD11b/CD18)-dependent manner the adhesion of HSPCs to BM stromal cells and increases the secretion of SDF-1 by BM stroma. We conclude that an increase in BM levels of proteolytic enzyme-resistant S1P and C1P and activation of CC, which leads to the generation of MAC, has an important and previously underappreciated role in the homing of transplanted HSPCs.

Expression of secreted and membrane-bound mucins in the airways of piglets experimentally infected with Mycoplasma hyopneumoniae

Immunohistochemistry was used to demonstrate secreted mucins MUC2, MUC5AC and MUC5B and membrane-bound mucin MUC4 in the pulmonary bronchioles of piglets experimentally infected with Mycoplasma hyopneumoniae. Conventional status, Landrace-Duroc cross-bred piglets, 13 days of age, were randomised to two groups. One group (n=20) was infected by the intra-tracheal route with the SNU98703 strain of M. hyopneumoniae, and a group of 12 animals acted as uninfected controls. Five infected and three uninfected piglets were euthanased on the day of infection and at 7, 21, and 35 days post-inoculation (PI). Membrane-bound MUC4 and secreted MUC5AC were the predominant mucins produced in the bronchioles of the piglets in response to M. hyopneumoniae infection, but by day 35 PI, all labelled mucins had returned to pre-infection levels, contemporaneous with reduced pulmonary lesion scores. The increased mucin production may result from direct stimulation of the epithelium by mycoplasmal infection, or may arise indirectly following M. hyopneumoniae-induced ciliostasis.

Analysis of global transcriptional responses of chicken following primary and secondary Eimeria acervulina infections

Background

Characterization of host transcriptional responses during coccidia infections can provide new clues for the development of alternative disease control strategies against these complex protozoan pathogens.

Methods

In the current study, we compared chicken duodenal transcriptome profiles following primary and secondary infections with Eimeria acervulina using a 9.6K avian intestinal intraepithelial lymphocyte cDNA microarray (AVIELA).

Results

Gene Ontology analysis showed that primary infection significantly modulated the levels of mRNAs for genes involved in the metabolism of lipids and carbohydrates as well as those for innate immune-related genes. By contrast, secondary infection increased the levels of transcripts encoded by genes related to humoral immunity and reduced the levels of transcripts for the innate immune-related genes. The observed modulation in transcript levels for gene related to energy metabolism and immunity occurred concurrent with the clinical signs of coccidiosis.

Conclusions

Our results suggest that altered expression of a specific set of host genes induced by Eimeria infection may be responsible, in part, for the observed reduction in body weight gain and inflammatory gut damage that characterizes avian coccidiosis.

Expression of RUNX3 in skin cancers

BACKGROUND

Expression of Runt-related transcription factor 3 (RUNX3) is reduced in a large number of cancers. However, a few studies have reported higher expression of RUNX3 in several cancers, including basal cell carcinoma (BCC). In light of this, we explored the expression of RUNX3 in skin cancers generally, to determine whether it acts as an oncogene or a tumour-suppressor gene in skin tumours.

AIM

To investigate the expression of RUNX3 in normal skin and malignant skin tumours.

METHODS

RUNX3 expression was evaluated by western blotting in 24 specimens, comprising 6 malignant melanoma (MM), 6 squamous cell carcinoma (SCC), 6 BCC and 6 normal skin specimens. Immunohistochemical staining was carried out to analyse RUNX3 expression in 16 MM, 16 SCC and 16 BCC specimens. To identify where the protein was expressed, the cytoplasmic and nuclear protein expression of RUNX3 in skin cancer tissues was determined. A cell-proliferation study was performed on an MM line (G361) by small interfering (si)RNA transfection.

RESULTS

The western blotting experiments showed that RUNX3 was not expressed in normal skin tissues, but it was overexpressed in all MM and SCC samples, and in five of the six BCC samples. Using immunochemistry, RUNX3 was found to be overexpressed in all cancer tissues analysed. Subcellular fraction analysis revealed that RUNX3 was expressed in the nuclei but not the cytoplasm of all the skin cancer tissues analysed, and RUNX3 silencing by siRNA in G361 cells resulted in a decrease in proliferation.

CONCLUSIONS

Based on these results, we suggest that RUNX3 has an oncogenic potential and does not act as a tumour suppressor in skin cancers.

Molecular inflammation as an underlying mechanism of the aging process and age-related diseases

Aging is a biological process characterized by time-dependent functional declines that are influenced by changes in redox status and by oxidative stress-induced inflammatory reactions. An organism's pro-inflammatory status may underlie the aging process and age-related diseases. In this review, we explore the molecular basis of low-grade, unresolved, subclinical inflammation as a major risk factor for exacerbating the aging process and age-related diseases. We focus on the redox-sensitive transcription factors, NF-κB and FOXO, which play essential roles in the expression of pro-inflammatory mediators and anti-oxidant enzymes, respectively. Major players in molecular inflammation are discussed with respect to the age-related up-regulation of pro-inflammatory cytokines and adhesion molecules, cyclo-oxygenase-2, lipoxygenase, and inducible nitric oxide synthase. The molecular inflammation hypothesis proposed by our laboratory is briefly described to give further molecular insights into the intricate interplay among redox balance, pro-inflammatory gene activation, and chronic age-related inflammatory diseases. The final section discusses calorie restriction as an aging-retarding intervention that also exhibits extraordinarily effective anti-inflammatory activity by modulating GSH redox, NF-κB, SIRT1, PPARs, and FOXOs.

Comparative efficacy of commercial Mycoplasma hyopneumoniae and porcine circovirus 2 (PCV2) vaccines in pigs experimentally infected with M. hyopneumoniae and PCV2

The efficacies of two commercial Mycoplasma hyopneumoniae bacterins and porcine circovirus 2 (PCV2) vaccines were compared in conventional pigs immunized at different ages based on humoral response, pathological observation, and growth performance from birth to finishing (175 days of age) using a M. hyopneumoniae and PCV2 co-infection challenge model. One-week-old pigs (n=110) were randomly assigned to five groups: three vaccinated and challenged (VC), and one each of non-vaccinated and challenged (NVC) and negative control. A significant difference was found in the number of genomic copies of M. hyopneumoniae in nasal swabs and PCV2 in serum samples, the average daily weight gain (gram/pig/day) between 63 and 133 dpi, gross and histopathological lung lesion scores, histopathological lymph node lesion scores, and the immunohistochemical analysis of PCV2 among the three VC groups. The single dose schedule for M. hyopneumoniae bacterins and PCV2 vaccines have the advantages of (i) improving daily weight gain (122.4%) and slaughter weight (120.5%), and (ii) reducing the incidence of clinical signs and lung and lymph node lesions.

Clinical characteristics and outcomes of H1N1-associated pneumonia among adults in South Korea

BACKGROUND

Pneumonia has been reported to be the most life-threatening complication of influenza virus infection.

OBJECTIVE

to describe clinical characteristics and determine risk factors for death among patients with H1N1-associated pneumonia.

DESIGN

A retrospective cohort study included all adult patients diagnosed and treated with H1N1-associated pneumonia in 14 participating institutions between 1 May 2009 and 28 February 2010 in South Korea. Clinical outcomes were summarised and predictors for death evaluated through univariate and multivariate analysis.

RESULTS

A total of 269 adult patients with H1N1-associated pneumonia were diagnosed and treated. Hospital visits or admissions peaked in November 2009, coinciding with the peak in the 2009 H1N1 epidemic in South Korea. The patients' median age was 48 years; 143 were male. Most (n = 266, 98.9%) were admitted for treatment: 97 (36.1%) required intensive care and 28 (10.4%) needed mechanical ventilation. Despite the use of antiviral and antibacterial agents, 19 patients (7.1%) died. Risk factors predictive of death included presence of malignancy (aOR 12.0, 95%CI 2.8-51.5), and pneumonia severity index (PSI) score (aOR 1.03, 95%CI 1.01-1.04).

CONCLUSION

Deaths among adult patients with H1N1-associated pneumonia were not rare. Clinicians should be aware of the possibility of a poor prognosis among H1N1-associated pneumonia patients with underlying malignancy or high PSI score.

Synthesis of cold antihydrogen in a cusp trap

We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which consists of a superconducting anti-Helmholtz coil and a stack of multiple ring electrodes. This success opens a new path to make a stringent test of the CPT symmetry via high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atoms.

Target structure induced suppression of the ionization cross section for very low energy antiproton-hydrogen collisions

Low energy antiprotons have been used previously to give benchmark data for theories of atomic collisions. Here we present measurements of the cross section for single, nondissociative ionization of molecular hydrogen for impact of antiprotons with kinetic energies in the range 2-11 keV, i.e., in the velocity interval of 0.3-0.65 a.u. We find a cross section which is proportional to the projectile velocity, which is quite unlike the behavior of corresponding atomic cross sections, and which has never previously been observed experimentally.

Innate immunity as orchestrator of stem cell mobilization

Hematopoietic stem and progenitor cells (HSPCs), as well as other types of stem cells, circulate under steady-state conditions at detectable levels in peripheral blood (PB), with their numbers increasing in response to stress, inflammation and tissue/organ injury. This mobilization process may be envisioned as a danger-sensing response mechanism triggered by hypoxia or mechanical or infection-induced tissue damage that recruits into PB different types of stem cells that have a role in immune surveillance and organ/tissue regeneration. Mobilization is also significantly enhanced by the administration of pharmacological agents, which has been exploited in hematological transplantology as a means to obtain HSPCs for hematopoietic reconstitution. In this review we will present mounting evidence that innate immunity orchestrates this evolutionarily conserved mechanism of HSPC mobilization.

Progesterone is primary regulator of Cdk2ap1 gene expression and tissue-specific expression in the uterus

Proliferation of endometrial cells is a prerequisite step for functional differentiation in the uterus. A tumor suppressor gene, Cyclin-dependent kinase 2-associated protein 1 (Cdk2ap1) mRNA was detected in the pregnant uterus and was suggested to be involved in cell proliferation. However, its roles and the mechanisms regulating its expression are largely unknown. In this study, the role of steroid hormones in the expression of Cdk2ap1 was examined using RT-PCR, Northern blotting and in situ hybridization methods. Cdk2ap1 mRNA was highly expressed during the proestrus phase and was mainly localized in the epithelium and subepithelium. Its expression was induced by a single injection of estradiol and progesterone, but the effect of progesterone was stronger than that of estradiol. Injections of progesterone (P1,2) on 2 consecutive days induced Cdk2ap1 expression in the endometrium with the same patterns observed in the proestrus phase, but injections of estradiol (E1,2) on 2 consecutive days did not induce expression. The Cdk2ap1 mRNA level was decreased by combined treatment of progesterone and estradiol (E1+P2,3). RU486 suppressed completely the Cdk2ap1 mRNA expression in P1,2 while ICI 182,780 did not in E1+P2,3. In the uteri on day 4 of gestation, expression of Cdk2ap1 also was regulated by progesterone as expected. Cdk2ap1 mRNA expression was totally suppressed by RU486 but not by ICI 182,780. Thus, it is suggested that Cdk2ap1 expression is primarily regulated by progesterone and the progesterone receptor in uterus and is mainly localized to proliferating tissues.

Control of transferrin expression by β-amyloid through the CP2 transcription factor

Accumulation of β-amyloid protein (Aβ) is one of the most important pathological features of Alzheimer's disease. Although Aβ induces neurodegeneration in the cortex and hippocampus through several molecular mechanisms, few studies have evaluated the modulation of transcription factors during Aβ-induced neurotoxicity. Therefore, in this study, we investigated the transcriptional activity of transcription factor CP2 in neuronal damage mediated by Aβ (Aβ(1-42) and Aβ(25-35) ). An unbiased motif search of the transferrin promoter region showed that CP2 binds to the transferrin promoter, an iron-regulating protein, and regulates transferrin transcription. Ectopic expression of CP2 led to increased transferrin expression at both the mRNA and protein levels, whereas knockdown of CP2 down-regulated transferrin mRNA and protein expression. Moreover, CP2 trans-activated transcription of a transferrin reporter gene. An electrophoretic mobility shift assay and a chromatin immunoprecipitation assay showed that CP2 binds to the transferrin promoter region. Furthermore, the binding affinity of CP2 to the transferrin promoter was regulated by Aβ, as Aβ (Aβ(1-42) and Aβ(25-35) ) markedly increased the binding affinity of CP2 for the transferrin promoter. Taken together, these results suggest that CP2 contributes to the pathogenesis of Alzheimer's disease by inducing transferrin expression via up-regulating its transcription.

Adaptation of a mallard H5N2 low pathogenicity influenza virus in chickens with prior history of infection with infectious bursal disease virus

The influenza A/Mallard/Pennsylvania/10218/1984 (H5N2) virus is unable to replicate in 3-wk-old immunocompetent specific-pathogen-free chickens when a dose of 5 x 10(6) 50% egg infectious dose/ml is used. In contrast, this mallard virus shows limited replication in 3-wk-old chickens that had been previously infected at 2 days of age with, and recovered from, the immunosuppressive agent infectious bursal disease virus (IBDV; herein referred to as IBDV chickens). This limited replication in IBDV chickens allowed for the serial passage of the mallard influenza virus in chickens. After 22 passages (P22) in IBDV chickens, the resulting chicken-adapted influenza virus replicated in both immunocompetent and IBDV chickens more efficiently than the mallard influenza virus. Analysis of the outcomes of infection and the lesions caused by the two viruses at the microscopic level in a time-point study showed that the P22 virus is more virulent than the parental mallard virus in both immunocompetent and IBDV chickens. Our studies provide evidence that a previous history of IBDV infection in chickens may render them more susceptible to avian influenza virus (AIV) infections, allowing for the potential introduction of AIVs in an otherwise resistant population.

Survival of Clostridium perfringens During Baking and Holding of Turkey Stuffing

Vegetative cells of three strains of Clostridium perfringens were used as inoculum for bread and onion stuffing for eight lightweight and eight heavyweight turkeys. When stuffed turkeys were refrigerated (5 +/- 1 C for 24 +/- 2 hr), a mean count of 580 vegetative cells of C. perfringens per gram of stuffing was reduced to undetectable levels (<6 per gram) in six of the eight. An inoculum of spores of the three strains used in a second series survived refrigerated holding with no change in numbers. During cooking of the stuffed turkeys in an oven at 94 C, numbers of vegetative cells fell steadily and numbers of spores remained constant or increased slightly (2 of 16 stuffings), until the temperature of the stuffing rose above that permitting growth. Viable C. perfringens cells were recovered from the stuffings at the end of cooking plus 1 hr for the group inoculated with the spore suspension. Storage of these stuffings resulted in marked reductions in numbers after 6 days at 5 +/- 1 C and in increases after 24 +/- 2 hr at 23 +/- 1 C. Cells of a strain which produces spores not considered heat-resistant survived in stuffing in birds cooked to doneness in ovens at 94, 163, and 232 C. In accepted methods of cooking stuffed turkeys, C. perfringens contaminants may survive and create a hazard if subsequent storage is in a temperature range which permits their multiplication.