Conversion of monoclonal IgG to dimeric and secretory IgA restores neutralizing ability and prevents infection of Omicron lineages

The emergence of Omicron lineages and descendent subvariants continues to present a severe threat to the effectiveness of vaccines and therapeutic antibodies. We have previously suggested that an insufficient mucosal immunoglobulin A (IgA) response induced by the mRNA vaccines is associated with a surge in breakthrough infections. Here, we further show that the intramuscular mRNA and/or inactivated vaccines cannot sufficiently boost the mucosal secretory IgA response in uninfected individuals, particularly against the Omicron variant. We thus engineered and characterized recombinant monomeric, dimeric, and secretory IgA1 antibodies derived from four neutralizing IgG monoclonal antibodies (mAbs 01A05, rmAb23, DXP-604, and XG014) targeting the receptor-binding domain of the spike protein. Compared to their parental IgG antibodies, dimeric and secretory IgA1 antibodies showed a higher neutralizing activity against different variants of concern (VOCs), in part due to an increased avidity. Importantly, the dimeric or secretory IgA1 form of the DXP-604 antibody significantly outperformed its parental IgG antibody, and neutralized the Omicron lineages BA.1, BA.2, and BA.4/5 with a 25- to 75-fold increase in potency. In human angiotensin converting enzyme 2 (ACE2) transgenic mice, a single intranasal dose of the dimeric IgA DXP-604 conferred prophylactic and therapeutic protection against Omicron BA.5. Thus, dimeric or secretory IgA delivered by nasal administration may potentially be exploited for the treatment and prevention of Omicron infection, thereby providing an alternative tool for combating immune evasion by the current circulating subvariants and, potentially, future VOCs.

Design, structure and plasma binding of ancestral β-CoV scaffold antigens

We report the application of ancestral sequence reconstruction on coronavirus spike protein, resulting in stable and highly soluble ancestral scaffold antigens (AnSAs). The AnSAs interact with plasma of patients recovered from COVID-19 but do not bind to the human angiotensin-converting enzyme 2 (ACE2) receptor. Cryo-EM analysis of the AnSAs yield high resolution structures (2.6-2.8 Å) indicating a closed pre-fusion conformation in which all three receptor-binding domains (RBDs) are facing downwards. The structures reveal an intricate hydrogen-bonding network mediated by well-resolved loops, both within and across monomers, tethering the N-terminal domain and RBD together. We show that AnSA-5 can induce and boost a broad-spectrum immune response against the wild-type RBD as well as circulating variants of concern in an immune organoid model derived from tonsils. Finally, we highlight how AnSAs are potent scaffolds by replacing the ancestral RBD with the wild-type sequence, which restores ACE2 binding and increases the interaction with convalescent plasma.

19n01, a broadly neutralizing antibody against Omicron BA.1, BA.2, BA.4/5, and other SARS-CoV-2 variants of concern

This study reports the isolation and characterization of a human monoclonal antibody (mAb) called 19n01. This mAb was isolated by using single-cell RNAseq of B cells from donors infected with the ancestral strain. This mAb possesses a potent and broad capacity to bind and neutralize all previously circulating variants of concern (VOCs), including Omicron sublineages BA.1, BA.2, and BA.4/5. The pseudovirus neutralization assay revealed robust neutralization capacity against the G614 strain, BA.1, BA.2, and BA.4/5, with inhibitory concentration (IC50) values ranging from 0.0035 to 0.0164 μg/mL. The microneutralization assay using the G614 strain and VOCs demonstrated IC50 values of 0.013-0.267 μg/mL. Biophysical and structural analysis showed that 19n01 cross-competes with ACE2 binding to the receptor-binding domain (RBD) and the kinetic parameters confirmed the high affinity against the Omicron sublineages (K_D of 61 and 30 nM for BA.2 and BA.4/5, respectively). These results suggest that the 19n01 is a remarkably potent and broadly reactive mAb.

Lactobacilli Downregulate Transcription Factors in Helicobacter pylori That Affect Motility, Acid Tolerance and Antimicrobial Peptide Survival

Helicobacter pylori infection triggers inflammation that may lead to gastritis, stomach ulcers and cancer. Probiotic bacteria, such as Lactobacillus, have been of interest as treatment options, however, little is known about the molecular mechanisms of Lactobacillus-mediated inhibition of H. pylori pathogenesis. In this work, we investigated the effect of Lactobacillus culture supernatants, so-called conditioned medium (CM), from two gastric isolates, L. gasseri and L. oris, on the expression of transcriptional regulators in H. pylori. Among the four known two-component systems (TCSs), i.e., ArsRS, FlgRS, CheAY and CrdRS, the flagellar regulator gene flgR and the acid resistance associated arsS gene were down-regulated by L. gasseri CM, whereas expression of the other TCS-genes remained unaffected. L. gasseri CM also reduced the motility of H. pylori, which is in line with reduced flgR expression. Furthermore, among six transcription factors of H. pylori only the ferric uptake regulator gene fur was regulated by L. gasseri CM. Deletion of fur further led to dramatically increased sensitivity to the antimicrobial peptide LL-37. Taken together, the results highlight that released/secreted factors of some lactobacilli, but not all, downregulate transcriptional regulators involved in motility, acid tolerance and LL-37 sensitivity of H. pylori.

Lactate causes downregulation of Helicobacter pylori adhesin genes sabA and labA while dampening the production of proinflammatory cytokines

Chronic inflammation induced by Helicobacter pylori is strongly associated with gastric cancer development, which is influenced by both bacterial virulence and host genetics. The sialic acid-binding adhesin SabA and the MUC5AC-binding adhesin LabA are important H. pylori virulence factors that facilitate adhesion of the bacterium, which is a crucial step in colonization. Lactate utilization has been reported to play a key role in the pathogenicity of different bacterial species. However, this is poorly understood in H. pylori. In this study, we investigated the effect of lactate on H. pylori adhesin gene expression and the regulation of host inflammatory cytokines. We show that the bacterial adhesins SabA and LabA were downregulated at the transcriptional level during incubation of H. pylori with lactate. Downregulation of sabA required the involvement of the two-component system ArsRS, while labA was regulated via the CheA/CheY system, indicating differences in the regulation of these genes in response to lactate. The levels of the proinflammatory cytokines TNF and IL-6 in H. pylori-stimulated macrophages were reduced when lactate was present. Interestingly, glucose did not prevent the secretion of these cytokines. Taken together, our data suggest that lactate affects H. pylori adhesin gene expression and the host response upon infection.

Genetic and immunologic evaluation of children with inborn errors of immunity and severe or critical COVID-19

BACKGROUND

Most severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals are asymptomatic or only exhibit mild disease. In about 10% of cases, the infection leads to hypoxemic pneumonia, although it is much more rare in children.

OBJECTIVE

We evaluated 31 young patients aged 0.5 to 19 years who had preexisting inborn errors of immunity (IEI) but lacked a molecular diagnosis and were later diagnosed with coronavirus disease 2019 (COVID-19) complications.

METHODS

Genetic evaluation by whole-exome sequencing was performed in all patients. SARS-CoV-2-specific antibodies, autoantibodies against type I IFN (IFN-I), and inflammatory factors in plasma were measured. We also reviewed COVID-19 disease severity/outcome in reported IEI patients.

RESULTS

A potential genetic cause of the IEI was identified in 28 patients (90.3%), including mutations that may affect IFN signaling, T- and B-cell function, the inflammasome, and the complement system. From tested patients 65.5% had detectable virus-specific antibodies, and 6.8% had autoantibodies neutralizing IFN-I. Five patients (16.1%) fulfilled the diagnostic criteria of multisystem inflammatory syndrome in children. Eleven patients (35.4%) died of COVID-19 complications. All together, at least 381 IEI children with COVID-19 have been reported in the literature to date. Although many patients with asymptomatic or mild disease may not have been reported, severe presentation of COVID-19 was observed in 23.6% of the published cases, and the mortality rate was 8.7%.

CONCLUSIONS

Young patients with preexisting IEI may have higher mortality than children without IEI when infected with SARS-CoV-2. Elucidating the genetic basis of IEI patients with severe/critical COVID-19 may help to develop better strategies for prevention and treatment of severe COVID-19 disease and complications in pediatric patients.

Heterologous immunization with inactivated vaccine followed by mRNA-booster elicits strong immunity against SARS-CoV-2 Omicron variant

The recent emergence of the Omicron variant has raised concerns on vaccine efficacy and the urgent need to study more efficient vaccination strategies. Here we observed that an mRNA vaccine booster in individuals vaccinated with two doses of inactivated vaccine significantly increased the plasma level of specific antibodies that bind to the receptor-binding domain (RBD) or the spike (S) ectodomain (S1 + S2) of both the G614 and the Omicron variants, compared to two doses of homologous inactivated vaccine. The level of RBD- and S-specific IgG antibodies and virus neutralization titers against variants of concern in the heterologous vaccination group were similar to that in individuals receiving three doses of homologous mRNA-vaccine or a boost of mRNA vaccine after infection, but markedly higher than that in individuals receiving three doses of a homologous inactivated vaccine. This heterologous vaccination regime furthermore significantly enhanced the RBD-specific memory B cell response and S1-specific T cell response, compared to two or three doses of homologous inactivated vaccine. Our study demonstrates that mRNA vaccine booster in individuals vaccinated with inactivated vaccines can be highly beneficial, as it markedly increases the humoral and cellular immune responses against the virus, including the Omicron variant.

Lung function before and after COVID-19 in young adults: A population-based study

Background

There is limited evidence on the long-term impact of mild-to-moderate coronavirus disease 2019 (COVID-19) on lung function among young adults.

Objectives

We aimed to assess whether COVID-19 has a negative impact on lung function in young adults and whether asthma, allergic sensitization, or use of inhaled corticosteroids (ICSs) modifies a potential association.

Methods

Participants from the population-based BAMSE (Barn, Allergi, Miljö, Stockholm, Epidemiologi) cohort with spirometry assessed before (2016-2019) and after onset of the COVID-19 pandemic (2020-2021) were included. Serum levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain-specific IgG, IgM, and/or IgA (determined with ELISA) defined seropositivity. Mean change in lung function (ie, change in FEV₁, forced vital capacity [FVC], and FEV₁/FVC ratio expressed as percent of predicted [pp]) from before to after onset of the pandemic were compared between the seronegative and seropositive participants. In seropositive participants, change in lung function was assessed in relation to allergic sensitization and self-reported ICS use.

Results

Of the 853 included participants, 29% (n = 243) were seropositive. There were no differences in change in lung function between the seronegative and seropositive participants (for mean change in FEV₁ pp [SD], seropositivity = 0.87% [4.79%] and seronegativity = 1.03% (4.76%) [P = .66] for difference using a t test; FVC pp (SD), seropositivity = 1.34% (4.44%) and seronegativity = 1.29% (4.27%) [P = .87]; and for FEV₁/FVC pp (SD), seropositivity = -0.25% (3.13%) and seronegativity = -0.13% (3.15%) [P = .61]). Similar results were observed among participants with asthma (n = 147 [17%]). Among seropositive participants, allergic sensitization or ICS use did not influence lung function.

Conclusion

We found no evidence of mild-to-moderate COVID-19 affecting lung function long term in a population-based cohort of young adults. Moreover, neither asthma nor allergic sensitization nor ICS use affected the results.

Human serum from SARS-CoV-2-vaccinated and COVID-19 patients shows reduced binding to the RBD of SARS-CoV-2 Omicron variant

BACKGROUND

The COVID-19 pandemic is caused by the betacoronavirus SARS-CoV-2. In November 2021, the Omicron variant was discovered and immediately classified as a variant of concern (VOC), since it shows substantially more mutations in the spike protein than any previous variant, especially in the receptor-binding domain (RBD). We analyzed the binding of the Omicron RBD to the human angiotensin-converting enzyme-2 receptor (ACE2) and the ability of human sera from COVID-19 patients or vaccinees in comparison to Wuhan, Beta, or Delta RBD variants.

METHODS

All RBDs were produced in insect cells. RBD binding to ACE2 was analyzed by ELISA and microscale thermophoresis (MST). Similarly, sera from 27 COVID-19 patients, 81 vaccinated individuals, and 34 booster recipients were titrated by ELISA on RBDs from the original Wuhan strain, Beta, Delta, and Omicron VOCs. In addition, the neutralization efficacy of authentic SARS-CoV-2 wild type (D614G), Delta, and Omicron by sera from 2× or 3× BNT162b2-vaccinated persons was analyzed.

RESULTS

Surprisingly, the Omicron RBD showed a somewhat weaker binding to ACE2 compared to Beta and Delta, arguing that improved ACE2 binding is not a likely driver of Omicron evolution. Serum antibody titers were significantly lower against Omicron RBD compared to the original Wuhan strain. A 2.6× reduction in Omicron RBD binding was observed for serum of 2× BNT162b2-vaccinated persons. Neutralization of Omicron SARS-CoV-2 was completely diminished in our setup.

CONCLUSION

These results indicate an immune escape focused on neutralizing antibodies. Nevertheless, a boost vaccination increased the level of anti-RBD antibodies against Omicron, and neutralization of authentic Omicron SARS-CoV-2 was at least partially restored. This study adds evidence that current vaccination protocols may be less efficient against the Omicron variant.

Immunity to SARS-CoV-2 up to 15 months after infection

Information concerning the longevity of immunity to SARS-CoV-2 following natural infection may have considerable implications for durability of immunity induced by vaccines. Here, we monitored the SARS-CoV-2 specific immune response in COVID-19 patients followed up to 15 months after symptoms onset. Following a peak at day 15–28 postinfection, the IgG antibody response and plasma neutralizing titers gradually decreased over time but stabilized after 6 months. Compared to G614, plasma neutralizing titers were more than 8-fold lower against variants Beta, Gamma, and Delta. SARS-CoV-2-specific memory B and T cells persisted in the majority of patients up to 15 months although a significant decrease in specific T cells, but not B cells, was observed between 6 and 15 months. Antiviral specific immunity, especially memory B cells in COVID-19 convalescent patients, is long-lasting, but some variants of concern may at least partially escape the neutralizing activity of plasma antibodies.

•

Plasma neutralizing antibodies persist in the majority of patients up to 15 months

•

Neutralizing activity is lower against variants of concern Delta, Beta, and Gamma

•

Specific memory B and T cells were present in 95% of patients up to 15 months

•

Specific T cells, but not B cells, were decreased between 6 and 15 months

Factors associated with treatment escalation among MS specialists and general neurologists: Results from an International cojoint study

BACKGROUND

Previous studies in multiple sclerosis (MS) showed that therapeutic inertia (TI) affects 60-90% of neurologists and up to 25% of daily treatment decisions. The objective of this study was to determine the most common factors and attribute levels associated with decisions to treatment escalation in an international study in MS care.

METHODS

300 neurologists with MS expertise from 20 countries were invited to participate. Participants were presented with 12 pairs of simulated MS patient profiles described by 13 clinically relevant factors. We used disaggregated discrete choice experiments to estimate the weight of factors and attributes affecting physicians' decisions when considering treatment selection. Participants were asked to select the ideal candidate for treatment escalation from modest to higher-efficacy therapies.

RESULTS

Overall, 229 neurologists completed the study (completion rate: 76.3%). The top 3 weighted factors associated with treatment escalation were: previous relapses (20%), baseline expanded disability status scale [EDSS] (18%), and MRI activity (13%). Patient demographics and desire for pregnancy had a modest influence (≤ 3%). We observed differences in the weight of factors associated with treatment escalation between MS specialists and non-MS specialists.

CONCLUSIONS

Our results provide critical information on factors influencing neurologists' treatment decisions and should be applied to continuing medical education strategies.

Inherited IFNAR1 Deficiency in a Child with Both Critical COVID-19 Pneumonia and Multisystem Inflammatory Syndrome

Background

Inborn errors of immunity (IEI) and autoantibodies to type I interferons (IFNs) underlie critical COVID-19 pneumonia in at least 15% of the patients, while the causes of multisystem inflammatory syndrome in children (MIS-C) remain elusive.

Objectives

To detect causal genetic variants in very rare cases with concomitant critical COVID-19 pneumonia and MIS-C.

Methods

Whole exome sequencing was performed, and the impact of candidate gene variants was investigated. Plasma levels of cytokines, specific antibodies against the virus, and autoantibodies against type I IFNs were also measured.

Results

We report a 3-year-old child who died on day 56 of SARS-CoV-2 infection with an unusual clinical presentation, combining both critical COVID-19 pneumonia and MIS-C. We identified a large, homozygous loss-of-function deletion in IFNAR1, underlying autosomal recessive IFNAR1 deficiency.

Conclusions

Our findings confirm that impaired type I IFN immunity can underlie critical COVID-19 pneumonia, while suggesting that it can also unexpectedly underlie concomitant MIS-C. Our report further raises the possibility that inherited or acquired dysregulation of type I IFN immunity might contribute to MIS-C in other patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10875-022-01215-7.

SARS-CoV-2-specific B- and T-cell immunity in a population-based study of young Swedish adults

Background

Young adults are now considered major spreaders of coronavirus disease 2019 (COVID-19) disease. Although most young individuals experience mild to moderate disease, there are concerns of long-term adverse health effects. The impact of COVID-19 disease and to which extent population-level immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exists in young adults remain unclear.

Objective

We conducted a population-based study on humoral and cellular immunity to SARS-CoV-2 and explored COVID-19 disease characteristics in young adults.

Methods

We invited participants from the Swedish BAMSE (Barn [Children], Allergy Milieu, Stockholm, Epidemiology) birth cohort (age 24-27 years) to take part in a COVID-19 follow-up. From 980 participants (October 2020 to June 2021), we here present data on SARS-CoV-2 receptor-binding domain–specific IgM, IgA, and IgG titers measured by ELISA and on symptoms and epidemiologic factors associated with seropositivity. Further, SARS-CoV-2–specific memory B- and T-cell responses were detected for a subpopulation (n = 108) by ELISpot and FluoroSpot.

Results

A total of 28.4% of subjects were seropositive, of whom 18.4% were IgM single positive. One in 7 seropositive subjects was asymptomatic. Seropositivity was associated with use of public transport, but not with sex, asthma, rhinitis, IgE sensitization, smoking, or body mass index. In a subset of representative samples, 20.7% and 35.0% had detectable SARS-CoV-2 specific B- and T-cell responses, respectively. B- and T-cell memory responses were clearly associated with seropositivity, but T-cell responses were also detected in 17.2% of seronegative subjects.

Conclusions

Assessment of IgM and T-cell responses may improve population-based estimations of SARS-CoV-2 infection. The pronounced surge of both symptomatic and asymptomatic infections among young adults indicates that the large-scale vaccination campaign should be continued.

Building on existing tools to improve chronic disease prevention and screening in public health: a cluster randomized trial

BACKGROUND

The BETTER (Building on Existing Tools to Improve Chronic Disease Prevention and Screening in Primary Care) intervention was designed to integrate the approach to chronic disease prevention and screening in primary care and demonstrated effective in a previous randomized trial.

METHODS

We tested the effectiveness of the BETTER HEALTH intervention, a public health adaptation of BETTER, at improving participation in chronic disease prevention and screening actions for residents of low-income neighbourhoods in a cluster randomized trial, with ten low-income neighbourhoods in Durham Region Ontario randomized to immediate intervention vs. wait-list. The unit of analysis was the individual, and eligible participants were adults age 40-64 years residing in the neighbourhoods. Public health nurses trained as "prevention practitioners" held one prevention-focused visit with each participant. They provided participants with a tailored prevention prescription and supported them to set health-related goals. The primary outcome was a composite index: the number of evidence-based actions achieved at six months as a proportion of those for which participants were eligible at baseline.

RESULTS

Of 126 participants (60 in immediate arm; 66 in wait-list arm), 125 were included in analyses (1 participant withdrew consent). In both arms, participants were eligible for a mean of 8.6 actions at baseline. At follow-up, participants in the immediate intervention arm met 64.5% of actions for which they were eligible versus 42.1% in the wait-list arm (rate ratio 1.53 [95% confidence interval 1.22-1.84]).

CONCLUSION

Public health nurses using the BETTER HEALTH intervention led to a higher proportion of identified evidence-based prevention and screening actions achieved at six months for people living with socioeconomic disadvantage.

TRIAL REGISTRATION

NCT03052959 , registered February 10, 2017.

Advancing mechanistic understanding and bioengineering of probiotic lactobacilli and bifidobacteria by genome editing

Typical traditional probiotics lactobacilli and bifidobacteria are gaining great interest to be developed as living diagnostics and therapeutics for improving human health. However, the mechanistic basis underlying their inherent health beneficial property remain incompletely understood which can slow down the translational pipeline in the functional food and pharmaceutical field. Efficient genome editing will advance the understanding of the molecular mechanism of the probiotics' physiological properties and their interaction with the host and the host microbiota, thereby further promote the development of next-generation designer probiotics with improved robustness and tailored functionalities. With the expansion of genome editing strategies such as CRISPR-Cas-based tools and IPSD assisted genome engineering as well as other synthetic biology technologies, the research and application of these health-promoting bacteria for the food and pharmaceutical industry will be further enhanced.

A randomized surgical trial of mitral valve repair with leaflet resection versus leaflet preservation on functional mitral stenosis – primary results of the CAMRA CardioLink-2 trial

Background

The gold standard treatment for mitral valve regurgitation due to prolapse involves surgery with annuloplasty and either leaflet resection or leaflet preservation, with placement of artificial neochordae. It has been suggested that leaflet resection may be prone to functional mitral stenosis, whereby a patient may have a higher mitral gradient at peak exercise compared to a leaflet preservation strategy. Although both techniques are widely used, there has been no prospective randomized study conducted to compare these two techniques, particularly in regard to functional mitral stenosis.

Methods

A total of 104 patients with posterior leaflet prolapse were randomized to undergo mitral repair with either leaflet resection (N=54) or leaflet preservation (N=50) at 7 specialized Canadian cardiac centers. Patient age, proportion of female patients, and mean Society of Thoracic Surgeons risk score was 63.9±10.4 years, 19%, and 1.4% for those who underwent leaflet resection, and 66.3±10.8 years, 16%, and 1.9% for those who underwent leaflet preservation, respectively. The primary endpoint was the mean trans-mitral repair gradient at peak exercise 12-months after repair.

Results

Baseline characteristics were similar between the groups. At 12-months, the mean trans-mitral repair gradient at peak exercise in patients who underwent leaflet resection and preservation was 9.1±5.2 and 8.3±3.3 mmHg (P=0.4), respectively. The two groups had similar mean mitral valve gradient at rest (3.2±1.9 mmHg following resection and 3.1±1.1 mmHg following leaflet preservation, P=0.7). There was no between-group difference for the 6-minute walk distance (451±147 m and 481±95 m for the resection and preservation groups, respectively, P=0.3).

Conclusion

We report the first prospective surgical randomized trial to evaluate commonly used mitral valve repair strategies for posterior leaflet prolapse. Leaflet resection and leaflet preservation both yield acceptable results with no difference in postoperative valve gradient and functional status 12-months after surgical mitral valve repair.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Heart and Stroke Foundation of Canada

Role of Sortase A in Lactobacillus gasseri Kx110A1 Adhesion to Gastric Epithelial Cells and Competitive Exclusion of Helicobacter pylori

We have previously shown that Lactobacillus gasseri Kx110A1, a human stomach isolate, can colonize mouse stomach and reduce the initial colonization of Helicobacter pylori. Here, we investigated the role of sortase-dependent proteins (SDPs) involved in these functions by the construction of a mutant for srtA, the gene encoding the housekeeping sortase that covalently anchors SDPs to the cell surface. The srtA mutant showed a decrease in hydrophobicity and autoaggregation under acidic conditions, indicating the effect of SDPs on cell surface properties. Correspondingly, the srtA mutant lost the capacity to adhere to gastric epithelial cells, thus resulting in an inability to provide a physical barrier to prevent H. pylori adherence. These results indicate that sortase A is a key determinant of the cell surface properties of L. gasseri Kx110A1 and contributes to Lactobacillus-mediated exclusion of H. pylori. Understanding the molecular mechanisms by which lactobacilli antagonize H. pylori might contribute to the development of novel therapeutic strategies that take advantage of health-promoting bacteria and reduce the burden of antibiotic resistance.

P5602Comparison of innominate vs axillary artery cannulation for cerebral protection on neurocognitive outcomes in aortic surgery: a pre-specified analysis of the ACE CardioLink-3 randomised trial

Background

Success after aortic surgery depends on avoidance of neurocognitive dysfunction, thus novel adjuncts to proximal aortic surgery must be evaluated for efficacy of cerebral protection during circulatory arrest. We report the primary neurocognitive results from the ACE CardioLink-3 randomised controlled trial comparing innominate to axillary artery cannulation for cerebral protection (NCT02554032).

Methods

The primary safety endpoint was the proportion of patients with new radiologically severe ischaemic cerebral lesions found on post-operative versus pre-operative diffusion weighted magnetic resonance imaging (DW-MRI). Neurocognitive outcomes were assessed using the Mini-Mental State Exam (MMSE), and the Montreal Cognitive Assessment (MoCA). Continuous and binary outcomes were analysed using ANCOVA (controlling for baseline score) and chi-square/Fisher's exact tests.

Results

Of the 111 patients randomised, 102 patients were included in the primary safety per-protocol analysis. The primary safety outcome (significant new ischaemic lesions on DW-MRI) occurred in 34% in the innominate group and 38.8% in the axillary group (OR 0.81; 0.41 to 1.60; P=0.0009 for non-inferiority). Rates of post-operative stroke/transient ischaemic attack, seizure, delirium, and encephalopathy were similar between groups. The rate of patients with a post-operative MoCA score less than 26 was 44.9% and 39.1% in the innominate and axillary groups respectively (P=0.807). A post-operative MMSE score of less than 24 was observed in 2% vs. 6.5% of the patients in the innominate and axillary groups respectively (P=0.866). A >1-point decrease in the MoCA score from pre-operatively to post-operatively was seen in 32.7% and 34.8% in the innominate and axillary groups respectively (P=0.962). A >1-point decrease in the MMSE score from pre-to post-operative was observed in 20.4% in the innominate artery group compared with 30.4% in the axillary group (P=0.346).

Conclusion

Post-operative neurocognitive dysfunction and DW-MRI incidence of severe ischaemic lesions did not differ in patients randomised to innominate artery cannulation vs, conventional axillary artery cannulation, though the burden of new severe ischaemic lesions is high in both groups.

P3753Does empagliflozin modulate the autonomic system among patients with type 2 diabetes and coronary artery disease? Insights from the Holter sub-study of the EMPA-Heart CardioLink-6 Randomised Trial

Introduction

The mechanism behind how empagliflozin, a sodium-glucose co-transporter 2 (SGLT2) inhibitor, reduces all-cause and cardiovascular mortality among patients with type 2 diabetes (T2DM) and coronary artery disease (CAD) is unknown. Autonomic tone, as reflected by changes in heart rate variability (HRV), is an established prognosticator in patients with CAD and/or heart failure.

Purpose

To assess if empagliflozin treatment changes HRV in subjects with T2DM and CAD.

Methods

In the double-blind EMPA-Heart trial, 97 subjects with T2DM and CAD were randomised to empagliflozin 10 mg/day or placebo for 6 months and underwent 24-hour Holter monitoring at baseline and 6 months. Using automated algorithms, time and frequency HRV domain measures were obtained (standard deviation of NN intervals (SDNN); SD of the average NN intervals for each 5-minute segment (SDANN); root mean square of successive RR interval differences (rMSSD); % interval differences of successive NN intervals >50 ms (pNN50); ratio of low to high frequency (LF/HF)). Changes of these HRV parameters were calculated over 6 months. Between-group differences in HRV parameters were compared using ANCOVA.

Results

Complete Holter data (baseline and 6-month) were available for 68% (n=66) of the cohort. The average heart rate (HR) at baseline/6 months was 69.5±9.8 bpm/72.8±8.1 bpm and 76±10.4 bpm/76.5±10.6 in the placebo group and empagliflozin group, respectively. Both groups had similar changes in average HR over 6 months. Key Holter data are summarised in the table. SDNN and SDANN were higher in the placebo vs. empagliflozin group at 6 months; no significant difference was noted for all other measures.

Empagliflozin 10 mg/day (n=33) Placebo (n=33) Adjusted difference between Empagliflozin and Placebo (ANCOVA) Baseline, Mean (SD) 6-month, Mean (SD) Baseline, Mean (SD) 6-month, Mean (SD) Mean, (95% CI) P-value SDNN (ms) 100.49 (43.74) 98.05 (38.86) 109.35 (30.02) 125.08 (43.83) −18.55 (−34.28, −2.82) 0.022 SDANN (ms) 86.84 (39.34) 83.76 (35.53) 94.70 (28.52) 118.28 (77.41) −20.24 (−37.27, −3.21) 0.021 rMSSD (ms) 27.00 (11.84) 27.22 (13.48) 28.00 (11.58) 27.17 (9.38) −1.23 (−6.02, 3.55) 0.608 pNN50 (%) 7.81 (7.59) 8.32 (9.51) 8.26 (7.8) 6.93 (5.35) 0.51 (−2.61, 3.62) 0.746 LF/HF ratio 1.63 (0.52) 1.65 (0.51) 1.53 (0.43) 1.83 (0.82) −0.08 (−0.38, 0.22) 0.602

Conclusions

Among subjects with T2DM and CAD, changes in HRV over 6 months were similar in the empagliflozin and placebo arms suggesting that the mortality benefit conferred by empagliflozin is not associated with positive modulation of autonomic tone.

Acknowledgement/Funding

This trial was supported by an unrestricted investigator-initiated study grant from Boehringer Ingelheim.

An exploratory pilot study evaluating the supplementation of standard antibiotic therapy with probiotic lactobacilli in south African women with bacterial vaginosis

Background

To reduce acquisition and relapse of bacterial vaginosis (BV), lactobacilli must be maintained in the vaginal microbiome. Probiotic lactobacilli may aid this purpose. We investigated whether vaginal probiotics (containing Lactobacillus rhamnosus DSM 14870 and Lactobacillus gasseri DSM 14869) would result in vaginal colonisation with lactobacilli in women with and without BV.

Methods

This prospective, partially randomised, exploratory pilot study was conducted in Soweto, South Africa. Thirty-nine sexually-active, HIV negative women were enrolled from October 2014 to May 2016 into three arms. Women who did not have BV (Group 1, n = 13) self-administered probiotic capsules vaginally once daily for 30 days, then once a week until Day 190. Women diagnosed with BV were randomized into Group 2 (n = 12) or Group 3 (n = 14) and treated with the triple oral antibiotic combination for vaginal discharge syndrome per South African guidelines (cefixime 400 mg stat, doxycycline 100 mg BD for 7 days and metronidazole 2 g stat). Immediately after antibiotic treatment, women in Group 2 self-administered probiotic capsules vaginally once daily for 30 days then vaginally once a week until Day 190. Women in Group 3 were not given lactobacilli.

Results

During the study, L. rhamnosus DSM 14870 or L. gasseri DSM 14869, were isolated in 5/13 (38.5%) women in Group 1 compared to 10/12 (83.3%) women in Group 2 (p = 0.041). The 1-month and 6-month BV cure rates were similar (P >  0.05) between Group 2 (42 and 25%) compared to Group 3 (36 and 25%). In Group 2, no correlation was observed between the frequency of isolation of the two Lactobacillus strains and the 1-month or 6-month cure rate.

Conclusions

Supplementation with vaginal probiotic capsules resulted in colonisation of the vagina by the Lactobacillus strains (L. rhamnosus DSM 14870 and L. gasseri DSM 14869) contained in the capsules. We observed low initial cure rates of BV after a stat dose of metronidazole and that the probiotic did not improve BV cure rates or alleviate recurrence which could be due to treatment failure or very limited power of the study.

Trial registration

Registered at the Pan African Clinical Trial Registry (www.pactr.org) on April 13, 2018 (retrospectively registered). Trial identification number: PACTR201804003327269.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4425-1) contains supplementary material, which is available to authorized users.

Comparison of mRNA expression from Y-chromosome X-degenerate region genes in taurine cattle, yaks and interspecific hybrid bulls

The yattle (dzo) is an interspecific hybrid of the taurine cattle (Bos taurus) and the domestic yak (Bos grunniens). F₁ hybrid yattle bulls are sterile due to spermatogenic arrest and have misregulation of spermatogenesis genes in the testes. However, the expression pattern of Y chromosome-linked genes in cattle, yaks and yattle testes is still unknown. In this study, we analyzed the mRNA expression pattern of 10 genes known to be present as single copies in the X-degenerate region of the bovine male-specific region of the Y chromosome. Using male-specific primers and reverse transcription quantitative PCR, the ubiquitously transcribed tetratricopeptide repeat gene, Y-linked (UTY), oral-facial-digital syndrome 1, Y-linked (OFD1Y) and ubiquitin specific peptidase 9, Y-linked (USP9Y) genes were ubiquitously expressed and significantly more highly expressed in yattle than in cattle and yaks testes (P < 0.001). RNA binding motif protein, Y-linked (RBMY) had testes-specific expression, and eukaryotic translation initiation factor 1A, Y-linked (EIF1AY) was expressed mainly in testis, whereas yattle and cattle did not show significant differences with respect to the expression of RBMY and EIF1AY. Thus, based on the model of yattle bull sterility, the high expression of UTY, OFD1Y and USP9Y may be associated with yattle infertility.

Inducible Plasmid Self-Destruction (IPSD) Assisted Genome Engineering in Lactobacilli and Bifidobacteria

Genome engineering is essential for application of synthetic biology in probiotics including lactobacilli and bifidobacteria. Several homologous recombination system-based mutagenesis tools have been developed for these bacteria, but still have many limitations in different species or strains. Here we developed a genome engineering method based on an inducible self-destruction plasmid delivering homologous DNA into bacteria. Excision of the replicon by induced recombinase facilitates selection of homologous recombination events. This new genome editing tool called inducible plasmid self-destruction (IPSD) was successfully used to perform gene knockout and knock-in in lactobacilli and bifidobacteria. Due to its simplicity and universality, the IPSD strategy may provide a general approach for genetic engineering of various bacterial species.

Exopolysaccharide-Producing Bifidobacterium adolescentis Strains with Similar Adhesion Property Induce Differential Regulation of Inflammatory Immune Response in Treg/Th17 Axis of DSS-Colitis Mice

Intestinal bifidobacteria benefit human health by promoting and modulating the gut flora, and boosting therapeutic efficiency for chronic metabolic diseases and cancer. Recently, Bifidobacterium adolescentis strains with high adhesion to intestinal epithelial cells were associated with induction of T-helper 17 (Th17) cells in humans and rodents. Here, two B. adolescentis strains with similar adhesive ability but different aggregation properties were investigated for specific immunoregulatory effects, including the underlying cellular pathway, on macrophage and T-regulatory (Treg)/Th17 axis activation in vitro and in the colon of dextran sodium sulfate (DSS)-colitis mice in vivo. In-vitro, the auto-aggregative B. adolescentis strain IF1-11 induced significantly higher IL-6 and lower IL-10 secretion from immune cells, and it induced abundant Th17 cells. The non-aggregating strain IF1-03 induced significantly higher IL-10, less IL-6 and a high proportion of Treg/Th17 cells compared to total T cells. In vivo, orally administered IF1-03 protected DSS-colitis mice via activation of dendritic cells or macrophages and skewing of Treg/Th17 cells, consistent with Treg cell induction in vitro. IF1-03 exopolysaccharides showed a functional recognition pattern similar to IF1-03 for IL-10 cytokine secretion and Treg cell-differentiation induction, both dependent on the toll-like receptor 2–ERK/p38 MAPK-signaling cascade for macrophage activation. We suggest that B. adolescentis exopolysaccharide-associated enterocyte adhesion/aggregation phenotypes determine strain-specific adaptive immune responses in the gut via the macrophage-regulated Treg/Th17 axis.

Deletion of D-Lactate Dehydrogenase A in Neisseria meningitidis Promotes Biofilm Formation Through Increased Autolysis and Extracellular DNA Release

Neisseria meningitidis is a Gram-negative bacterium that asymptomatically colonizes the human nasopharyngeal mucosa. Pilus-mediated initial adherence of N. meningitidis to the epithelial mucosa is followed by the formation of three-dimensional aggregates, called microcolonies. Dispersal from microcolonies contributes to the transmission of N. meningitidis across the epithelial mucosa. We have recently discovered that environmental concentrations of host cell-derived lactate influences N. meningitidis microcolony dispersal. Here, we examined the ability of N. meningitidis mutants deficient in lactate metabolism to form biofilms. A lactate dehydrogenease A (ldhA) mutant had an increased level of biofilm formation. Deletion of ldhA increased the N. meningitidis cell surface hydrophobicity and aggregation. In this study, we used FAM20, which belongs to clonal complex ST-11 that forms biofilms independently of extracellular DNA (eDNA). However, treatment with DNase I abolished the increased biofilm formation and aggregation of the ldhA-deficient mutant, suggesting a critical role for eDNA. Compared to wild-type, the ldhA-deficient mutant exhibited an increased autolytic rate, with significant increases in the eDNA concentrations in the culture supernatants and in biofilms. Within the ldhA mutant biofilm, the transcription levels of the capsule, pilus, and bacterial lysis genes were downregulated, while norB, which is associated with anaerobic respiration, was upregulated. These findings suggest that the absence of ldhA in N. meningitidis promotes biofilm formation and aggregation through autolysis-mediated DNA release.

Transcriptomic analysis of Bifidobacterium longum subsp. longum BBMN68 in response to oxidative shock

Bifidobacterium longum strain BBMN68 is sensitive to low concentrations of oxygen. A transcriptomic study was performed to identify candidate genes for B. longum BBMN68's response to oxygen treatment (3%, v/v). Expression of genes and pathways of B. longum BBMN68 involved in nucleotide metabolism, amino acid transport, protein turnover and chaperones increased, and that of carbohydrate metabolism, translation and biogenesis decreased to adapt to the oxidative stress. Notably, expression of two classes of ribonucleotide reductase (RNR), which are important for deoxyribonucleotide biosynthesis, was rapidly and persistently induced. First, the class Ib RNR NrdHIEF was immediately upregulated after 5 min oxygen exposure, followed by the class III RNR NrdDG, which was upregulated after 20 min of exposure. The upregulated expression of branched-chain amino acids and tetrahydrofolate biosynthesis-related genes occurred in bifidobacteria in response to oxidative stress. These change toward to compensate for DNA and protein damaged by reactive oxygen species (ROS). In addition, oxidative stress resulted in improved B. longum BBMN68 cell hydrophobicity and autoaggregation. These results provide a rich resource for our understanding of the response mechanisms to oxidative stress in bifidobacteria.

Characterization of a lactose-responsive promoter of ATP-binding cassette (ABC) transporter gene from Lactobacillus acidophilus 05-172

A novel lactose-responsive promoter of the ATP-binding cassette (ABC) transporter gene Lba1680 of Lactobacillus acidophilus strain 05-172 isolated from a traditionally fermented dairy product koumiss was characterized. In L. acidophilus 05-172, expression of Lba1680 was induced by lactose, with lactose-induced transcription of Lba1680 being 6.1-fold higher than that induced by glucose. This is in contrast to L. acidophilus NCFM, a strain isolated from human feces, in which expression of Lba1680 and Lba1679 is induced by glucose. Both gene expression and enzyme activity assays in L. paracasei transformed with a vector containing the inducible Lba1680 promoter (PLba1680) of strain 05-172 and a heme-dependent catalase gene as reporter confirmed that PLba1680 is specifically induced by lactose. Its regulatory expression could not be repressed by glucose, and was independent of cAMP receptor protein. This lactose-responsive promoter might be used in the expression of functional genes in L. paracasei incorporated into a lactose-rich environment, such as dairy products.

Heterologous Expression and Delivery of Biologically Active Exendin-4 by Lactobacillus paracasei L14

Exendin-4, a glucagon-like protein-1 (GLP-1) receptor agonist, is an excellent therapeutic peptide drug for type 2 diabetes due to longer lasting biological activity compared to GLP-1. This study explored the feasibility of using probiotic Lactobacillus paracasei as an oral vector for recombinant exendin-4 peptide delivery, an alternative to costly chemical synthesis and inconvenient administration by injection. L. paracasei transformed with a plasmid encoding the exendin-4 gene (L. paracasei L14/pMG76e-exendin-4) with a constitutive promotor was successfully constructed and showed efficient secretion of exendin-4. The secreted exendin-4 significantly enhanced insulin secretion of INS-1 β-cells, along with an increment in their proliferation and inhibition of their apoptosis, corresponding to the effect of GLP-1 on these cells. The transcription level of the pancreatic duodenal homeobox-1 gene (PDX-1), a key transcription factor for cellular insulin synthesis and secretion, was upregulated by the treatment with secreted exendin-4, paralleling the upregulation of insulin gene expression. Caco-2 cell monolayer permeability assay showed a 34-fold increase in the transport of exendin-4 delivered by L. paracasei vs. that of free exendin-4 (control), suggesting effective facilitation of exendin-4 transport across the intestinal barrier by this delivery system. This study demonstrates that the probiotic Lactobacillus can be engineered to secrete bioactive exendin-4 and facilitate its transport through the intestinal barrier, providing a novel strategy for oral exendin-4 delivery using this lactic acid bacterium.

[Effectiveness of bupropion and counseling for smoking cessation]

OBJECTIVE

To evaluate the effectiveness of bupropion for smoking cessation among Chinese smokers at a smoking cessation clinic.

METHODS

A prospective observational study was conducted in a hospital located in Beijing during 2008 and from 28 to 31 October 2014. A total of 287 smokers (265 men and 22 women) were assessed using data from structured questionnaires at baseline and were followed up at 1 and 6 months. Trained physician counselors provided free brief education and individual counseling sessions for all participants at the first visit. A total 131 participants were prescribed bupropion in addition to counseling. The counseling plus bupropion group was compared with the group who underwent counseling without bupropion. Outcomes were self-reported 7-day point prevalence abstinence rates at 1- and 6-month follow-up and continuous abstinence rates at 6-month follow-up. Smoking reduction rates at 1 and 6 months were also measured.

RESULTS

By intention-to-treat analysis, the 7-day point prevalence abstinence rate of the bupropion group at 1 and 6 months was higher than for the counseling-only group: at 1-month follow-up, 26.0% (34/131) vs. 15.4% (24/156), with OR (95% CI) 1.93(1.07-3.46); these rates at 6-month follow-up were 27.8% (35/131) vs. 15.4% (24/156), with OR (95% CI) 2.01(1.12-3.59). The 1-month continuous abstinence rate at 6 months was higher in the bupropion group: 26.0% (34/131) vs. 14.7% (23/156), with OR (95%CI) 2.03(1.12-3.66). Participants in the bupropion group also had a higher smoking reduction rate at 1 month than those in the counseling-only group: 55.0% (72/131) vs. 38.5% (60/156), with OR (95%CI) 1.95 (1.22-3.13).

CONCLUSION

Prescription of bupropion at this smoking cessation clinic was effective in doubling the quitting rates and smoking reduction rates among Chinese smokers.

Recombinant Lactococcus lactis NZ9000 secretes a bioactive kisspeptin that inhibits proliferation and migration of human colon carcinoma HT-29 cells

Background

Proteinaceous bioactive substances and pharmaceuticals are most conveniently administered orally. However, the facing problems are the side effects of proteolytic degradation and denaturation in the gastrointestinal tract. In recent years, lactic acid bacteria (LAB) have been verified to be a promising delivery vector for susceptible functional proteins and drugs. KiSS-1 peptide, a cancer suppressor, plays a critical role in inhibiting cancer metastasis and its activity has been confirmed by direct administration. However, whether this peptide can be functionally expressed in LAB and exert activity on cancer cells, thus providing a potential alternative administration manner in the future, has not been demonstrated.

Results

A recombinant Lactococcus lactis strain NZ9000-401-kiss1 harboring a plasmid containing the gene of the tumor metastasis-inhibiting peptide KiSS1 was constructed. After optimization of the nisin induction conditions, the recombinant strain efficiently secreted KiSS1 with a maximum detectable amount of 27.9 μg/ml in Dulbecco’s Modified Eagle medium. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide and would healing assays, respectively, indicated that the secreted KiSS1 peptide remarkably inhibited HT-29 cell proliferation and migration. Furthermore, the expressed KiSS1 was shown to induce HT-29 cell morphological changes, apoptosis and reduce the expression of matrix metalloproteinase 9 (MMP-9) at both mRNA and protein levels.

Conclusions

A recombinant L. lactis NZ9000-401-kiss1 successfully expressing the human kiss1 was constructed. The secreted KiSS1 peptide inhibited human HT-29 cells’ proliferation and migration probably by invoking, or mediating the cell-apoptosis pathway and by down regulating MMP-9 expression, respectively. Our results suggest that L. lactis is an ideal cell factory for secretory expression of tumor metastasis-inhibiting peptide KiSS1, and the KiSS1-producing L. lactis strain may serve as a new tool for cancer therapy in the future.

A randomized trial testing the efficacy of modifications to the nutrition facts table on comprehension and use of nutrition information by adolescents and young adults in Canada

INTRODUCTION

Given the proposed changes to nutrition labelling in Canada and the dearth of research examining comprehension and use of nutrition facts tables (NFts) by adolescents and young adults, our objective was to experimentally test the efficacy of modifications to NFts on young Canadians' ability to interpret, compare and mathematically manipulate nutrition information in NFts on prepackaged food.

METHODS

An online survey was conducted among 2010 Canadians aged 16 to 24 years drawn from a consumer sample. Participants were randomized to view two NFts according to one of six experimental conditions, using a between-groups 2 x 3 factorial design: serving size (current NFt vs. standardized serving-sizes across similar products) x percent daily value (% DV) (current NFt vs. "low/med/high" descriptors vs. colour coding). The survey included seven performance tasks requiring participants to interpret, compare and mathematically manipulate nutrition information on NFts. Separate modified Poisson regression models were conducted for each of the three outcomes.

RESULTS

The ability to compare two similar products was significantly enhanced in NFt conditions that included standardized serving-sizes (p ≤ .001 for all). Adding descriptors or colour coding of % DV next to calories and nutrients on NFts significantly improved participants' ability to correctly interpret % DV information (p ≤ .001 for all). Providing both standardized serving-sizes and descriptors of % DV had a modest effect on participants' ability to mathematically manipulate nutrition information to calculate the nutrient content of multiple servings of a product (relative ratio = 1.19; 95% confidence limit: 1.04-1.37).

CONCLUSION

Standardizing serving-sizes and adding interpretive % DV information on NFts improved young Canadians' comprehension and use of nutrition information. Some caution should be exercised in generalizing these findings to all Canadian youth due to the sampling issues associated with the study population. Further research is needed to replicate this study in a more heterogeneous sample in Canada and across a range of food products and categories.

Comparative genome-based identification of a cell wall-anchored protein from Lactobacillus plantarum increases adhesion of Lactococcus lactis to human epithelial cells

Adhesion to host cells is considered important for Lactobacillus plantarum as well as other lactic acid bacteria (LAB) to persist in human gut and thus exert probiotic effects. Here, we sequenced the genome of Lt. plantarum strain NL42 originating from a traditional Chinese dairy product, performed comparative genomic analysis and characterized a novel adhesion factor. The genome of NL42 was highly divergent from its closest neighbors, especially in six large genomic regions. NL42 harbors a total of 42 genes encoding adhesion-associated proteins; among them, cwaA encodes a protein containing multiple domains, including five cell wall surface anchor repeat domains and an LPxTG-like cell wall anchor motif. Expression of cwaA in Lactococcus lactis significantly increased its autoaggregation and hydrophobicity, and conferred the new ability to adhere to human colonic epithelial HT-29 cells by targeting cellular surface proteins, and not carbohydrate moieties, for CwaA adhesion. In addition, the recombinant Lc. lactis inhibited adhesion of Staphylococcus aureus and Escherichia coli to HT-29 cells, mainly by exclusion. We conclude that CwaA is a novel adhesion factor in Lt. plantarum and a potential candidate for improving the adhesion ability of probiotics or other bacteria of interest.

Combination of heterogeneous catalase and superoxide dismutase protects Bifidobacterium longum strain NCC2705 from oxidative stress

Bifidobacteria are generally sensitive to oxidative stress caused by reactive oxygen species (ROS). To improve oxidative-stress tolerance, the superoxide dismutase (SOD) gene from Streptococcus thermophilus (StSodA) and the heme-dependent catalase (KAT) gene from Lactobacillus plantarum (LpKatL) were heterologously expressed in Bifidobacterium longum strain NCC2705. Three types of strain NCC2705 transformants were obtained: with transgenic SOD expression, with transgenic KAT expression, and with coexpression of the two genes. Intracellular expression of the genes and their functional role in oxidative-stress resistance were evaluated. In response to oxidative stress, B. longum NCC2705/pDP401-LpKatL (expressing LpKatL) and NCC2705/pDP-Kat-Sod (coexpressing LpKatL and StSodA) rapidly degraded exogenous H2O2 and the peroxides generated as a byproduct of aerobic cultivation, preventing oxidative damage to DNA and RNA. Individual expression of StSodA or LpKatL both improved B. longum NCC2705 cell viability. Survival rate of strain NCC2705 was further improved by combining SOD and KAT expression. The two enzymes played complementary roles in ROS-scavenging pathways, and coexpression led to a synergistic beneficial effect under conditions of intensified oxidative stress. Our results illustrate that heterogeneous expression of heme-dependent KAT and Mn(2+)-dependent SOD is functional in the B. longum oxidative-stress response, and synergistic protection is achieved when their expressions are combined.

Mechanism of the reversal effect of mifepristone on drug resistance of the human cervical cancer cell line HeLa/MMC

We examined the ability of mifepristone to reverse the in vitro drug resistance of human cervical cancer cells resistant to mitomycin-C (HeLa/MMC) cells and investigated the mechanism of this effect. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to detect the drug resistance of HeLa/MMC cells and the reversed drug resistance in vitro. Expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and glucosylceramide synthase (GCS) were measured in HeLa and HeLa/MMC cells. The resistance index of HeLa/MMC cells on MMC was reduced from 5.02 to 1.46 after 10 mg/mL mifepristone exposure. A combination of mifepristone upregulated the Bax/Bcl-2 protein expression ratio and apoptosis in HeLa/MMC cells. GCS expression was significantly higher in HeLa/MMC cells than in HeLa cells (P < 0.01), but distinctly declined in both cell lines after mifepristone application (P < 0.01). Mifepristone reversed the resistance of HeLa/MMC cells to MMC in vitro; the overexpression of the GCS gene and the increased expression of apoptosis-related protein Bcl-2 may play important roles in the formation of multidrug resistance in cervical cancer.

Developing human capital for successful implementation of international marine scientific research projects

The oceans play a crucial role in the global environment and the sustainability of human populations, because of their involvement in climate regulation and provision of living and non-living resources to humans. Maintenance of healthy oceans in an era of increasing human pressure requires a high-level understanding of the processes occurring in the marine environment and the impacts of anthropogenic activities. Effective protection and sustainable resource management must be based, in part, on knowledge derived from successful research. Current marine research activities are being limited by a need for high-quality researchers capable of addressing critical issues in broad multidisciplinary research activities. This is particularly true for developing countries which will require the building of capacity for marine scientific research. This paper reviews the current activities aimed at increasing marine research capacity in developing and emerging countries and analyses the challenges faced, including: appropriate alignment of the research goals and societal and policy-relevant needs; training in multidisciplinary research; increasing capacity for overall synthesis of scientific data; building the capacity of technical staff; keeping highly qualified personnel in marine scientific research roles; cross-cultural issues in training; minimising duplication in training activities; improving linkages among human capital, project resources and infrastructure. Potential solutions to these challenges are provided, along with some priorities for action aimed at improving the overall research effort.

Oxidative stress-related responses of Bifidobacterium longum subsp. longum BBMN68 at the proteomic level after exposure to oxygen

Bifidobacterium longum subsp. longum BBMN68, an anaerobic probiotic isolated from healthy centenarian faeces, shows low oxygen (3 %, v/v) tolerance. To understand the effects of oxidative stress and the mechanisms protecting against it in this strain, a proteomic approach was taken to analyse changes in the cellular protein profiles of BBMN68 under the following oxygen-stress conditions. Mid-exponential phase BBMN68 cells grown in MRS broth at 37 °C were exposed to 3 % O2 for 1 h (I) or 9 h (II), and stationary phase cells were subjected to 3 % O2 for 1 h (III). Respective controls were grown under identical conditions but were not exposed to O2. A total of 51 spots with significant changes after exposure to oxygen were identified, including the oxidative stress-protective proteins alkyl hydroperoxide reductase C22 (AhpC) and pyridine nucleotide-disulfide reductase (PNDR), and the DNA oxidative damage-protective proteins DNA-binding ferritin-like protein (Dps), ribonucleotide reductase (NrdA) and nucleotide triphosphate (NTP) pyrophosphohydrolases (MutT1). Changes in polynucleotide phosphorylase (PNPase) plus enolase, which may play important roles in scavenging oxidatively damaged RNA, were also found. Following validation at the transcriptional level of differentially expressed proteins, the physiological and biochemical functions of BBMN68 Dps were further proven by in vitro and in vivo tests under oxidative stress. Our results reveal the key oxidative stress-protective proteins and DNA oxidative damage-protective proteins involved in the defence strategy of BBMN68 against oxygen, and provide the first proteomic information toward understanding the responses of Bifidobacterium and other anaerobes to oxygen stress.

[Study of deletion and mutation of p16 gene in primary hepatocellular carcinoma]

OBJECTIVE

To investigate the role the deletion and mutation of p16 gene plays in the pathogenesis of human primary hepatocarcinoma.

METHODS

Thirty-one cases of human hepatocarcinoma, 31 cases of adjacent noncancerous liver cirrhosis and the leukocytes of 8 normal human subjects were analyzed for deletion and mutation in p16 gene exons 1, 2 and introns 1, 2 with comparative multiple PCR and PCR-SSCP.

RESULTS

Deletion of p16 gene exon 1 and partial intron 1 was found in 4 of 31 cases (13/%). No deletion of exon 2 or intron 2 was found. Three patterns of p16 gene intron 1 and 18 bp-flanking sequence in exon 2 at SSCP analysis were observed in hepatocellular carcinoma and corresponding adjacent noncancerous cirrhosis, and two patterns were found in human normal leukocyte DNA. No aberrant single strand at SSCP in p16 gene exon 1 or most part of exon 2 or intron 2 was detected.

CONCLUSION

Low frequency of deletion and rare mutation of p16 suppressor gene occurred in hepatocellular carcinoma.

Determination of 14 chemical constituents in the traditional Chinese medicinal preparation Huangqin-Tang by high performance liquid chromatography

The high performance liquid chromatographic (HPLC) method for the identification and determination of baicalin (BG), wogonoside (WG), oroxylin-A-glucoside (OG), baicalein (B), wogonin (W), orxylin-A (O), paeoniflorin (PF), glycyrrhizic acid (GL), glycyrrhetinic acid (GA), liquiritin (LG), isoliquirition (ILG), liquiritigenin (L), isoliquiritigenin (IL) and ononin (ON) in Huangqin-Tang [Chinese characters: see text] was established. The samples were separated with a Wakosil C18 column (4.6 x 150 mm) by linear gradient elution using A (MeOH-HAC 100:1, v/v)-B (Water-HAC 100:1, v/v) (0 min, 30:70; 15 min, 40:60; 30 min, 60:40; 45 min, 80:20; 60 min, 100:0) as the mobile phase at a flow-rate of 1.0 ml/min. The detection was by diode-array UV/Vis detector (DAD), and the wavelength was set at the range of 200-400 nm. Satisfactory results were obtained within 60 min for the simultaneous determination of the 14 constituents. The repeatability (RSD) of the method was generally less than 2% (n=5, interday and intraday). The recovery of BG was 96.9+/-1.71, WG was 98.9+/-2.99, PF was 99.7+/-0.52, LG was 95.3+/-2.67, GL was 96.7+/-3.44, and GA was 94.8+/-4.16, respectively.

Global analysis of gene expression in pulmonary fibrosis reveals distinct programs regulating lung inflammation and fibrosis

The molecular mechanisms of pulmonary fibrosis are poorly understood. We have used oligonucleotide arrays to analyze the gene expression programs that underlie pulmonary fibrosis in response to bleomycin, a drug that causes lung inflammation and fibrosis, in two strains of susceptible mice (129 and C57BL/6). We then compared the gene expression patterns in these mice with 129 mice carrying a null mutation in the epithelial-restricted integrin beta6 subunit (beta6(-/-)), which develop inflammation but are protected from pulmonary fibrosis. Cluster analysis identified two distinct groups of genes involved in the inflammatory and fibrotic responses. Analysis of gene expression at multiple time points after bleomycin administration revealed sequential induction of subsets of genes that characterize each response. The availability of this comprehensive data set should accelerate the development of more effective strategies for intervention at the various stages in the development of fibrotic diseases of the lungs and other organs.

Development of muscarinic analgesics derived from epibatidine: role of the M4 receptor subtype

Epibatidine, a neurotoxin isolated from the skin of Epipedobates tricolor, is an efficacious antinociceptive agent with a potency 200 times that of morphine. The toxicity of epibatidine, because of its nonspecificity for both peripheral and central nicotinic receptors, precludes its development as an analgesic. During the synthesis of epibatidine analogs we developed potent antinociceptive agents, typified by CMI-936 and CMI-1145, whose antinociception, unlike that of epibatidine, is mediated via muscarinic receptors. Subsequently, we used specific muscarinic toxins and antagonists to delineate the muscarinic receptor subtype involved in the antinociception evoked by these agents. Thus, the antinociception produced by CMI-936 and CMI-1145 is inhibited substantially by 1) intrathecal injection of the specific muscarinic M4 toxin, muscarinic toxin-3; 2) intrathecally administered pertussis toxin, which inhibits the G proteins coupled to M2 and M4 receptors; and 3) s.c. injection of the M2/M4 muscarinic antagonist himbacine. These results demonstrate that the antinociception elicited by these epibatidine analogs is mediated via muscarinic M4 receptors located in the spinal cord. Compounds that specifically target the M4 receptor therefore may be of substantial value as alternative analgesics to the opiates.