Combination therapy of niclosamide with gemcitabine inhibited cell proliferation and apoptosis via Wnt/β-catenin/c-Myc signaling pathway by inducing β-catenin ubiquitination in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a type of cancer with high morbidity and mortality rates worldwide. Owing to a lack of therapeutic options, the overall survival rate of patients with pancreatic cancer is low. Gemcitabine has been mainly used to treat patients with pancreatic cancer, but its efficacy is limited by chemoresistance. Therefore, a novel therapeutic agent for PDAC therapy is urgently needed. An anthelminthic drug, niclosamide, has already been researched in breast, lung, colon, and pancreatic cancer as an anti-cancer purpose by re-positioning its original purpose. However, combination therapy of gemcitabine and niclosamide was not informed yet. Here, we found that niclosamide co-administered with gemcitabine significantly inhibited tumorigenesis of pancreatic cancer compared to gemcitabine alone. Further, combining niclosamide and gemcitabine inhibited cell proliferation and induced apoptosis. Niclosamide induced cell cycle arrest at the G1 phase, and the levels of CDK4/6 and cyclin D1 were lowered after gemcitabine treatment. In addition, the combination of these chemical compounds more effectively increased the binding level of activated β-catenin destruction complex and β-catenin to enable phosphorylation, compared to gemcitabine alone. After phosphorylation, niclosamide - gemcitabine upregulated the ubiquitin level, which caused phosphorylated β-catenin to undergo proteasomal degradation; the combination was more potent than gemcitabine alone. Finally, the combination more effectively suppressed tumor growth in vivo, compared to gemcitabine alone. Altogether, our results indicate that niclosamide synergistically enhances the antitumor effect of gemcitabine in pancreatic cancer, by inducing the degradation of β-catenin with ubiquitination. Therefore, this drug combination can potentially be used in PDAC therapy.

The role of LOXL2 induced by glucose metabolism-activated NF-κB in maintaining drug resistance through EMT and cancer stemness in gemcitabine-resistant PDAC

Gemcitabine is considered a standard treatment for pancreatic cancer, but developing drug resistance greatly limits the effectiveness of chemotherapy and increases the rate of recurrence. Lysyl oxide-like 2 (LOXL2) is highly expressed in pancreatic cancer and is involved in carcinogenesis and EMT regulation. However, studies on the role of LOXL2 in drug resistance are limited. Here, we investigated the mechanism of LOXL2 induction and the effect of LOXL2 on EMT and CSC in gemcitabine-resistant pancreatic cancer. Glucose metabolism was activated in gemcitabine-resistant pancreatic cancer cells, and NF-κB signaling was regulated accordingly. Activated NF-κB directly induces transcription by binding to the promoters of LOXL2 and ZEB1. The EMT process was significantly inhibited by the coregulation of ZEB1 and LOXL2. In addition, LOXL2 inhibition reduced the expression of cancer stemness markers and stemness by regulating MAPK signaling activity. LOXL2 inhibits tumor growth of gemcitabine-resistant pancreatic cancer cells and increases the sensitivity to gemcitabine in mouse models. KEY MESSAGES: We identified a specific mechanism for inducing LOXL2 overexpression in gemcitabine-resistant pancreatic cancer. Taken together, our results suggest LOXL2 has an important regulatory role in maintaining gemcitabine resistance and may be an effective therapeutic target to treat pancreatic cancer.

SLC38A5 Modulates Ferroptosis to Overcome Gemcitabine Resistance in Pancreatic Cancer

Pancreatic cancer is characterized by a poor prognosis, with its five-year survival rate lower than that of any other cancer type. Gemcitabine, a standard treatment for pancreatic cancer, often has poor outcomes for patients as a result of chemoresistance. Therefore, novel therapeutic targets must be identified to overcome gemcitabine resistance. Here, we found that SLC38A5, a glutamine transporter, is more highly overexpressed in gemcitabine-resistant patients than in gemcitabine-sensitive patients. Furthermore, the deletion of SLC38A5 decreased the proliferation and migration of gemcitabine-resistant PDAC cells. We also found that the inhibition of SLC38A5 triggered the ferroptosis signaling pathway via RNA sequencing. Also, silencing SLC38A5 induced mitochondrial dysfunction and reduced glutamine uptake and glutathione (GSH) levels, and downregulated the expressions of GSH-related genes NRF2 and GPX4. The blockade of glutamine uptake negatively modulated the mTOR-SREBP1-SCD1 signaling pathway. Therefore, suppression of SLC38A5 triggers ferroptosis via two pathways that regulate lipid ROS levels. Similarly, we observed that knockdown of SLC38A5 restored gemcitabine sensitivity by hindering tumor growth and metastasis in the orthotopic mouse model. Altogether, our results demonstrate that SLC38A5 could be a novel target to overcome gemcitabine resistance in PDAC therapy.

CD74 Promotes a Pro-Inflammatory Tumor Microenvironment by Inducing S100A8 and S100A9 Secretion in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive form of pancreatic cancer with a poor prognosis and low survival rates. The prognostic and predictive biomarkers of PDAC are still largely unknown. The receptor CD74 was recently identified as a regulator of oncogenic properties in various cancers. However, the precise molecular mechanism of CD74 action in PDAC remains little understood. We investigated the role of CD74 by silencing CD74 in the pancreatic cancer cell line Capan-1. CD74 knockdown led to reductions in cell proliferation, migration, and invasion and increased apoptosis. Moreover, silencing CD74 resulted in the decreased expression and secretion of S100A8 and S100A9. An indirect co-culture of fibroblasts and tumor cells revealed that fibroblasts exposed to conditioned media from CD74 knockdown cells exhibited a reduced expression of inflammatory cytokines, suggesting a role of CD74 in influencing cytokine secretion in the tumor microenvironment. Overall, our study provides valuable insights into the critical role of CD74 in regulating the oncogenic properties of pancreatic cancer cells and its influence on the expression and secretion of S100A8 and S100A9. Taken together, these findings indicate CD74 as a potential diagnostic biomarker and therapeutic target for pancreatic cancer.

Ivermectin and gemcitabine combination treatment induces apoptosis of pancreatic cancer cells via mitochondrial dysfunction

Pancreatic cancer is an aggressive cancer characterized by high mortality and poor prognosis, with a survival rate of less than 5 years in advanced stages. Ivermectin, an antiparasitic drug, exerts antitumor effects in various cancer types. This is the first study to evaluate the anticancer effects of the combination of ivermectin and gemcitabine in pancreatic cancer. We found that the ivermectin–gemcitabine combination treatment suppressed pancreatic cancer more effectively than gemcitabine alone treatment. The ivermectin–gemcitabine combination inhibited cell proliferation via G1 arrest of the cell cycle, as evidenced by the downregulation of cyclin D1 expression and the mammalian target of rapamycin (mTOR)/signal transducer and activator of transcription 3 (STAT-3) signaling pathway. Ivermectin–gemcitabine increased cell apoptosis by inducing mitochondrial dysfunction via the overproduction of reactive oxygen species and decreased the mitochondrial membrane potential. This combination treatment also decreased the oxygen consumption rate and inhibited mitophagy, which is important for cancer cell death. Moreover, in vivo experiments confirmed that the ivermectin–gemcitabine group had significantly suppressed tumor growth compared to the gemcitabine alone group. These results indicate that ivermectin exerts synergistic effects with gemcitabine, preventing pancreatic cancer progression, and could be a potential antitumor drug for the treatment of pancreatic cancer.

Intraoperative radiation therapy induces immune response activity after pancreatic surgery

Background

Pancreatic cancer has highly aggressive features, such as local recurrence that leads to significantly high morbidity and mortality and recurrence after successful tumour resection. Intraoperative radiation therapy (IORT), which delivers targeted radiation to a tumour bed, is known to reduce local recurrence by directly killing tumour cells and modifying the tumour microenvironment.

Methods

Among 30 patients diagnosed with pancreatic cancer, 17 patients received IORT immediately after surgical resection. We investigated changes in the immune response induced by IORT by analysing the peritoneal fluid (PF) and blood of patients with and without IORT treatment after pancreatic cancer surgery. Further, we treated three pancreatic cell lines with PF to observe proliferation and activity changes.

Results

Levels of cytokines involved in the PI3K/SMAD pathway were increased in the PF of IORT-treated patients. Moreover, IORT-treated PF inhibited the growth, migration, and invasiveness of pancreatic cancer cells. Changes in lymphocyte populations in the blood of IORT-treated patients indicated an increased immune response.

Conclusions

Based on the characterisation and quantification of immune cells in the blood and cytokine levels in the PF, we conclude that IORT induced an anti-tumour effect by activating the immune response, which may prevent pancreatic cancer recurrence.

Clinical trial registration

NCT03273374.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08807-3.

1357 Ankle Blocks: Improving Day Case Efficiency

Introduction

The COVID pandemic has exerted unprecedented pressure on hospital resources. Resulting in cancellation of elective operative services, increased patient waiting lists, limited surgical training opportunities along with reduced availability of staff, theatre, and in-patient bed capacity. A novel approach for day case forefoot surgery under ankle block, to mitigate the pandemic service limitations without compromising care, was developed.

Method

This is a 3-month, multi-centre, prospective cohort study evaluating the novel ankle block day case forefoot surgery pathway. Patients had a minimum of three months clinical follow up with outcome scores. They were matched to a cohort undergoing similar surgery prior to the COVID pandemic.

Results

The utilisation of an ankle block pathway resulted in an average reduction of inpatient stay by 2 days per patient. Over the study period conservative savings of £26,659 were calculated. Anecdotally we observed a reduction in morbidity (wound complications, SSI’s) although not statistically significant.

Conclusions

Our novel surgical pathway has enabled continued elective operating for procedures that previously required hospital admission during a period of severe restrictions within the NHS. We observed significant reductions in cost, surgical inpatient bed utilisation and total operative time with staff, resource, and time savings. We hypothesise that prehabilitation with physiotherapy, ankle instead of thigh tourniquets and early mobilisation may have contributed to improved morbidity scores. The findings of this project have implications for training, upper limb services and are transferrable as a template to improve service efficiency while maintaining high quality care.

Clinical evaluation of anesthesia for high-risk cesarean section at a tertiary medical center: retrospective study for 8 years (2009-2016)

Objective

The number of high-risk pregnancies is increasing in tertiary medical centers. Therefore, we investigated perioperative outcomes based on risk factors to ascertain proper maternal and neonatal management.

Methods

We reviewed the medical records of patients receiving cesarean sections over an 8-year period. Clinical parameters for anesthesia and the neonatal outcome were compared among high-risk groups after subdivision by the number of clinical risk factors. The groups were as follows: group A (one risk factor), group B (two risk factors), and group C (three or more risk factors).

Results

Patient age, estimated blood loss (EBL), and volume of transfused red blood cell (RBC) were higher in group B than group A. Birth weight, 1- and 5-minute Apgar scores, and gestational age were lower while the frequency of neonatal intensive care unit (NICU) admission was higher in group B than group A. Group C patients were significantly older than group A or B patients. Birth weight, 1- and 5-minute Apgar scores and gestational age were significantly lower while frequency of NICU admission was higher in group C than group A and B.

Conclusion

The number of maternal risk factors was positively associated with adverse outcomes in the neonates.

Acute Abdomen in a Cervical Spinal Cord Injury Patient: A Case Report and Review of the Literature

Acute abdomen, including appendicitis, is an emergent condition requiring early detection and, often, immediate surgical intervention. Although patients with spinal cord injury (SCI) have an incidence of acute abdomen similar to that of the general population, diagnosing them is even more difficult and complex than it is in the general population. Because of the disruption of normal sensory pathways, the early symptoms are subtle and physical examination of the abdomen is often not helpful. In addition, because of concomitant common conditions in SCI patients, such as urinary tract infection, atelectasis, pneumonia, and decubitus ulcer, laboratory results are not reliable. Delayed diagnoses lead to higher mortality rates among SCI patients with acute abdomen than those of the general population. We report a case of appendicitis in a patient with cervical SCI and discuss the clinical characteristics and diagnostic pitfalls of acute abdomen in SCI patients.

Proteolytic degradation and potential role of onconeural protein cdr2 in neurodegeneration

Cerebellar degeneration-related protein 2 (cdr2) is expressed in the central nervous system, and its ectopic expression in tumor cells of patients with gynecological malignancies elicits immune responses by cdr2-specific autoantibodies and T lymphocytes, leading to neurological symptoms. However, little is known about the regulation and function of cdr2 in neurodegenerative diseases. Because we found that cdr2 is highly expressed in the midbrain, we investigated the role of cdr2 in experimental models of Parkinson's disease (PD). We found that cdr2 levels were significantly reduced after stereotaxic injection of 1-methyl-4-phenylpyridinium (MPP(+)) into the striatum. cdr2 levels were also decreased in the brains of post-mortem PD patients. Using primary cultures of mesencephalic neurons and MN9D cells, we confirmed that MPP(+) reduces cdr2 in tyrosine hydroxylase-positive dopaminergic neuronal cells. The MPP(+)-induced decrease of cdr2 was primarily caused by calpain- and ubiquitin proteasome system-mediated degradation, and cotreatment with pharmacological inhibitors of these enzymes or overexpression of calcium-binding protein rendered cells less vulnerable to MPP(+)-mediated cytotoxicity. Consequently, overexpression of cdr2 rescued cells from MPP(+)-induced cytotoxicity, whereas knockdown of cdr2 accelerated toxicity. Collectively, our findings provide insights into the novel regulatory mechanism and potentially protective role of onconeural protein during dopaminergic neurodegeneration.

Genetic differences between the wild and hatchery-produced populations of Korean short barbeled grunter (Hapalogenys nitens) determined with microsatellite markers

Short barbeled grunter, Hapalogenys nitens, is an economically important fishery resource. In Korea, this fish is in the early stage of domestication, and it has been regarded as the candidate marine fish species for prospective aquaculture diversification. This study presents a preliminary investigation of the future viability of sustainable fry production from short barbeled grunter. We used 12 polymorphic nuclear microsatellite DNA loci to analyze the possible genetic variability between the wild and hatchery-produced populations of short barbeled grunter from Korea and identified 91 alleles. Compared to the wild population, significant genetic changes including reduced genetic diversity (average allele number: 7.42 vs 3.75; average expected heterozygosity: 0.713 vs 0.598, Wilcoxon signed-rank test; P < 0.05) and differentiation [overall fixation index (FST) = 0.088, P < 0.01] occurred in the hatchery-produced population, as indicated by the observation of allele richness, unique allele, heterozygosity, FST, and results of molecular analysis of variance. These findings indicate that genetic drift may have promoted the differentiation between these 2 populations, which may have negative effects on sustainable fry production. Therefore, genetic variations of the wild and hatchery-produced populations should be monitored and subjected to control inbreeding through a commercial breeding program. The information presented by this paper would provide a useful genetic basis for future sustainable culturing planning and management of H. nitens.

Effects of serial passage on the characteristics and chondrogenic differentiation of canine umbilical cord matrix derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) are often known to have a therapeutic potential in the cell-mediated repair for fatal or incurable diseases. In this study, canine umbilical cord MSCs (cUC-MSCs) were isolated from umbilical cord matrix (n = 3) and subjected to proliferative culture for 5 consecutive passages. The cells at each passage were characterized for multipotent MSC properties such as proliferation kinetics, expression patterns of MSC surface markers and self-renewal associated markers, and chondrogenic differentiation. In results, the proliferation of the cells as determined by the cumulative population doubling level was observed at its peak on passage 3 and stopped after passage 5, whereas cell doubling time dramatically increased after passage 4. Expression of MSC surface markers (CD44, CD54, CD61, CD80, CD90 and Flk-1), molecule (HMGA2) and pluripotent markers (sox2, nanog) associated with self-renewal was negatively correlated with the number of passages. However, MSC surface marker (CD105) and pluripotent marker (Oct3/4) decreased with increasing the number of subpassage. cUC-MSCs at passage 1 to 5 underwent chondrogenesis under specific culture conditions, but percentage of chondrogenic differentiation decreased with increasing the number of subpassage. Collectively, the present study suggested that sequential subpassage could affect multipotent properties of cUC-MSCs and needs to be addressed before clinical applications.

Isolation and Genetic Analysis of anAgrobacterium tumefaciensAvirulent Mutant with a Chromosomal Mutation Produced by Transposon Mutagenesis

A transposon 5 (Tn5) insertion was introduced into the genome of A. tumefaciens (A-208 strain harboring a nopaline type Ti-plasmid) using a conjugative pJB4JI plasmid containing Tn5. Five thousand transconjugants were assayed for virulence on carrot (Daucus carota L.) disks; 54 isolates were avirulent or very attenuated. The cellular localization (plasmid or chromosome) of the Tn5 insertion in those isolates were identified by Southern hybridization analysis. An avirulent mutant (B-90 strain) with the Tn5 insertion in the chromosome was selected and characterized. The mutant had the same growth rate as that of the parent strain in L-broth. The mutant and the parent strain had similar attachment ability to carrot root cells. Tn5 was inserted into one site of the chromosome. The wild-type target chromosomal region (1281 base pairs) was cloned and sequenced. An open reading frame (ORF) consisting of 395 base pairs was identified. The wild-type DNA fragment (1.6 kb) containing the ORF introduced into B-90 strain complemented the avirulent phenotype of the strain. A soluble protein was predicted from the ORF. The Tn5 was inserted near the 3'-terminal of the ORF. Homology search of this ORF found no significant homology to known genes and proteins. Thus, the ORF identified in this paper seems to be a new chromosomal virulence gene of A. tumefaciens.

Risks related with withholding and resuming anticoagulation in patients with non-variceal upper gastrointestinal bleeding while on warfarin therapy

BACKGROUND

The use of warfarin is growing for the prevention or treatment of cardiovascular or cerebrovascular diseases. The risk of haemorrhagic side effects is increased in patients taking warfarin.

AIMS

To evaluate risks related with withholding and resuming anticoagulation in patients with upper gastrointestinal bleeding (UGIB) while on warfarin therapy and the role of the second-look endoscopic examination (SEE).

METHODS

Records of 58 patients with native valvular heart diseases who presented with non-variceal UGIB during chronic anticoagulation with warfarin were retrospectively reviewed. Age- and gender-matched patients with non-variceal UGIB during aspirin therapy because of ischaemic heart disease were recruited as the control group.

RESULTS

Development of both recurrent bleeding and thromboembolic events were more frequent in warfarin group than in control group (7.0% vs. 0% with p = 0.03 and 16.7% vs. 2.4% with p < 0.01, respectively). One of four cases of recurrent bleeding in warfarin group was found by SEE performed in an asymptomatic patient. There were six thromboembolic events which occurred on the 21st, 27th, 28th, 31st, 58th and 75th day from the presentation out of 36 patients who ceased anticoagulation. In contrast, only one from 41 in whom aspirin was discontinued experienced myocardial infarction. There was no difference in the failure of endoscopic haemostasis necessitating angiographic embolisation or surgery, hospital stay, the need of transfusion and overall mortality.

CONCLUSIONS

Anticoagulation is recommended to be resumed before the 20th day from the cessation to prevent thromboembolic events. A routine SEE before resuming anticoagulation might be helpful to detect asymptomatic recurrent bleeding.

Calculus fragmentation in laser lithotripsy

The intracorporeal treatment of urinary calculi with lasers is presented, which describes laser-calculus interactions associated with lithotripsy. Reliable fragmentation of calculi with diverse compositions and minimal collateral tissue damage are primarily contingent upon laser parameters (wavelength, pulse duration, and pulse energy) and physical properties of calculi (optical, mechanical, and chemical). The pulse duration governs the dominant mechanism in calculi fragmentation, which is either photothermal or photoacoustical/photomechanical. Lasers with long pulse durations (i.e. > tens of micros) induce a temperature rise in the laser-affected zone with minimal acoustic waves; material is removed by means of vaporization, melting, mechanical stress, and/or chemical decomposition. Short-pulsed laser ablation (i.e. < 10 micros), on the other hand, produces shock waves, and the resultant mechanical energy fragments calculi. Work continues throughout the world to evaluate the feasibility of advanced lasers in lithotripsy and to optimize laser parameters and light delivery systems pertinent to efficient fragmentation of calculi.

Targeting of MPEG-protected polyamino acid carrier to human E-selectin in vitro

Targeted diagnostic agents are expected to have a significant impact in molecular imaging of cell-surface associated markers of proliferation, inflammation and angiogenesis. In this communication, we describe a new class of targeted polyamino acid-based protected graft copolymers (PGC) of poly-(L-lysine) and methyl poly-(ethylene glycol) (PGC) covalently conjugated with a monoclonal antibody fragment, F(ab')(2). We utilized targeted PGC conjugates as carriers of near-infrared indocyanine fluorophores (Cy5.5) for optical imaging of endothelial cell populations expressing IL-1 beta inducible proinflammatory marker E-selectin. We compared two conjugation chemistries, involving either introduction of sulfhydryl group to F(ab')(2), or via direct attachment of the antibody fragment directly to the chemically activated PGC. Both PGC-based targeted agents demonstrated high binding specificity (20-30 fold over non-specific uptake) and were utilized for imaging E-selectin expression on human endothelial cells activated with IL-1 beta.

Tobacco clones derived from tissue culture with supersensitivity to ozone

At least two supersensitive tobacco somaclones were obtained from tissue culture (TC) , when this approach was used to asexually propagate Bel-W3 tobacco indicator plants. These somaclones can detect as low as 30 ppb ozone for a 4-h exposure duration both within CSTR exposure chambers and in ambient air. Comparison of the injury index and their coefficient of variance showed that the TC plantlets usually have more uniform performance in response to ozone in addition to their higher sensitivity. A quick regeneration procedure was established to preserve the supersensitive germplasm immediately when it was found. The TC plantlets will flower and produce seed similar to seed-grown tobacco. The TC approach proved to be a better propagation system for valuable indicator plant species. The mechanism that causes the variation and the possible difference in their genome from seed-grown tobacco is still unknown. Further studies are needed in the future to determine if factors in the TC system may be responsible for the sensitivity difference.

Inhibitory action of water soluble fraction of Terminalia chebula on systemic and local anaphylaxis

We investigated the effects of the water soluble fraction of Terminalia chebula (Combretaceae) (WFTC) on systemic and local anaphylaxis. WFTC administered 1h before compound 48/80 injection inhibited compound 48/80-induced anaphylactic shock 100% with doses of 0.01-1.0 g/kg. When WFTC was administered 5 or 10 min after compound 48/80 injection, the mortality also decreased in a dose-dependent manner. Passive cutaneous anaphylaxis was inhibited by 63.5+/-7.8% by oral administration of WFTC (1.0 g/kg). When WFTC was pretreated at concentrations ranging from 0.005 to 1.0 g/kg, the serum histamine levels were reduced in a dose-dependent manner. WFTC (0.01-1.0 mg/ml) also significantly inhibited histamine release from rat peritoneal mast cells (RPMC) by compound 48/80. However, WFTC (1.0 mg/ml) had a significant increasing effect on anti-dinitrophenyl IgE-induced tumor necrosis factor-alpha production from RPMC. These results indicate that WFTC may possess a strong antianaphylactic action.

Fabrication of porous gelatin scaffolds for tissue engineering

A novel method which employs water present in swollen hydrogels as a porogen for shape template was suggested for preparing porous materials. Biodegradable hydrogels were prepared through crosslinking of gelatin with glutaraldehyde in aqueous solution, followed by rinsing and washing. After freezing the swollen hydrogels, the ice formed within the hydrogel network was sublimated by freeze-drying. This simple method produced porous hydrogels. Irrespective of any rinsing and washing processes, water was homogeneously distributed into the hydrogel network, allowing the hydrogel network to uniformly enlarge and the ice to act as a porogen during the freezing process. Different porous structures were obtained by varying the freezing temperature. Hydrogels frozen in liquid nitrogen, had a two-dimensionally ordered structure, while the hydrogels prepared at freezing temperatures near -20 degrees C, showed a three-dimensional structure with interconnected pores. As the freezing temperature was lowered, the hydrogel structure gradually became more two-dimensionally ordered. These results suggest that the porosity of dried hydrogels can be controlled by the size of ice crystals formed during freezing. It was concluded that the present freeze-drying procedure is a bio-clean method for formulating biodegradable sponges of different pore structures without use of any additives and organic solvents.

Phylogenetic analysis of Erwinia species based on 16S rRNA gene sequences

The phylogenetic relationships of the type strains of 16 Erwinia species were investigated by performing a comparative analysis of the sequences of the 16S rRNA genes of these organisms. The sequence data were analyzed by the neighbor-joining method, and each branch was supported by moderate bootstrap values. The phylogenetic tree and sequence analyses confirmed that the genus Erwinia is composed of species that exhibit considerable heterogeneity and form four clades that are intermixed with members of other genera, such as Escherichia coli, Klebsiella pneumoniae, and Serratia marcescens. Cluster I includes the type strains of Erwinia herbicola, Erwinia milletiae, Erwinia ananas, Erwinia uredovora, and Erwinia stewartii and corresponds to Dye's herbicola group. Cluster II consists of Erwinia persicinus, Erwinia rhapontici, Erwinia amylovora, and Erwinia cypripedii. Cluster III consists of Erwinia carotovora subspecies and Erwinia chrysanthemi and is characterized by the production of pectate lyases and cellulases. Erwinia salicis, Erwinia rubrifaciens, and Erwinia nigrifluens form the cluster that is most distantly related to other Erwinia species. The data from the sequence analyses are discussed in the context of biochemical and DNA-DNA hybridization data.

Cellular localization and functional analysis of the protein encoded by the chromosomal virulence gene(acvB) of Agrobacterium tumefaciens

A chromosomal virulence gene, acvB, of Agrobacterium tumefaciens [J. Bacteriol., 175, 3208-3212 (1993)] was over-expressed in Escherichia coli. A 47-kDa protein was produced and localized in the periplasmic space of E. coli. Amino acid sequence analysis of its N-terminal demonstrated that a signal peptide of 24 amino acids was cleaved from the pre AcvB protein to produce the mature 47-kDa protein. Western-blot analysis using the antiserum against the AcvB protein detected a 47-kDa protein in the periplasmic space only with strain A208 (acvB+). The amount of AcvB protein synthesized was not increased in strain A208 by induction with acetosyringone (100 microM). There was observed no significant difference in induction by acetosyringone of virB::lacZ, virD::lacZ, and virE::lacZ fusion genes regardless of the presence or absence of the acvB gene. The T-strand (lower strand of T-DNA) was detected in strains A208 as well as B119 (acvB-) which were cultured in induction medium containing acetosyringone. AcvB protein bound to single-stranded DNAs with no apparent sequence specificity. The results suggest that AcvB protein binds to the T-strand in periplasm and mediates the transfer of the T-strand from A. tumefaciens to the host plant cell.

Isolation and characterization of a new chromosomal virulence gene of Agrobacterium tumefaciens

A mutant (strain B119) of Agrobacterium tumefaciens with a chromosomal mutation was isolated by transposon (Tn5) mutagenesis. The mutant exhibited growth rates on L agar and minimal medium (AB) plates similar to those of the parent strain (strain A208 harboring a nopaline-type Ti plasmid). The mutant was avirulent on all host plants tested: Daucus carota, Cucumis sativus, and Kalanchoe diagremontiana. The mutant was not impaired in attachment ability to carrot cells. The mutant had one insertion of Tn5 in its chromosome. The avirulent phenotype of B119 was shown to be due to the Tn5 insertion in the chromosome by the marker exchange technique. A wild-type target chromosomal segment (3.0 kb) which included the site of mutation was cloned and sequenced. Two open reading frames, ORF-1 (468 bp) and ORF-2 (995 bp), were identified in the 3.0-kb DNA segment. Tn5 was inserted in the middle of ORF-2 (acvB gene). Introduction of the acvB gene into the mutant B119 strain complemented the avirulent phenotype of the strain. Homology search found no genes homologous to acvB, although it had some similarity to the open reading frame downstream of the virA gene on the Ti plasmid. Thus, the acvB gene identified in this study seems to be a new chromosomal virulence gene of A. tumefaciens.

Pulmonary lymphangioleiomyomatosis in a male

Pulmonary lymphangioleiomyomatosis has been observed almost exclusively in women, usually in their reproductive years. Exacerbations with pregnancy and after hormonal manipulation have been documented, and it has been suggested that its pathogenesis is due to the influence of hormonal(estrogenic) stimulus. The clinical, roentgenographic, and histopathologic features of this case of pulmonary lymphangioleiomyomatosis in a 22-year-old male are all characteristic of those described in prior reports, except for the patient's sex. With the following case of pulmonary lymphangioleiomyomatosis in a male, we suggest the possibility of the existence of an additional pathogenetic mechanism.