Background: JMML is a pediatric haematopoietic stem cell malignancy characterised by uncontrolled proliferation of myelomonocytic and progenitor compartments and a poor outcome. We comprehensively evaluated the genomic profile of JMML that presented to our hospital for diagnosis and treatment. Procedure: We developed a 51-gene (151.5kB) low-cost targeted myeloid panel based on single-molecule molecular inversion probes. A total of 50 children with clinical and pathological features of JMML were sequenced at high coverage on an Illumina MiSeq. The presenting clinical, laboratory and follow-up data were procured from the electronic medical record system of the institution. Results: The median age of our cohort was 2 years, with a male preponderance. Among the 50 patients, 43 (86%)harboured mutations in one of the RAS/MAPK-pathway genes, most frequently in PTPN11 (14, 28%), and NRAS (14, 28%), followed by NF1(11. 22%). Interestingly, 20% (10) of children had more than one mutation, with 5 cases harbouring two RAS-pathway mutations. Monosomy 7 was detected in 32% (16) patients, and five of these did not harbour any RAS-pathway mutations. The follow-up data revealed that 37 (74%) of these children had succumbed to the disease. Children with monosomy 7 showed shorter overall survival, compared to their wildtype counterparts (p=0.02). Conclusion: Our study highlights that comprehensive genomic profiling identifies at least one mutation in almost 90% of JMML patients. Performing genomic analysis early in evaluation of JMML might help in triaging patients for allogenic stem cell transplant in resource-constrained settings.

Background: Prophylactic anticoagulation was recommended for stroke prevention in patients with hypertrophic cardiomyopathy(HCM) and atrial fibrillation(AF) regardless of CHA2DS2-VASC score but the strategy was in a dilemma for patients with contraindication to antigulants. Aims: To estimate the safety and efficacy of left atrial appendage occlusion(LAAO) in HCM patients with atrial fibrillation(AF). Methods and results: This prospective study included 25 HCM patients(age 70.04±11.62years, 72% male, 16/25(64.00%) had prior stroke) with AF eligible for LAAO. Clinical outcomes and echocardiographic parameters were collected and assessed during procedure and follow-up(3, 6, and 12months post-procedure). The composite safety outcomes included all-cause death, major bleeding and procedure-related complications. The primary efficacy outcome was defined as ischemic stroke and systemic embolization. Successful implantation was achieved in 24 patients(96%) using Watchman device without severe peri-device leaks (PDL), while one patient developed new-onset thrombus before access puncture on the operative day. Median follow-up was 1.5 years with a total of 38.1 patient-years. Only one patient experienced non-disabling ischemic stroke. The occurrence of major bleeding was 1/24(4.17%), with a remarkable reduction in annual 3 bleeding risk by 56.18% compared to the predicted rate. Device-related thrombus(DRT) was detected in 3/24(12.50%) patients. Neither serious procedure-related complications nor death events were reported in our study. Conclusion: Our study suggested the feasibility and safety of LAAO in HCM patients for stroke prevention. Whereas, thrombus formation remains a concern depending on hemodynamic abnormality associated with HCM. Further follow-up visits on larger sample size would facilitate the evaluation of LAAO in this high-risk cohort.

Both acute otitis media (AOM) and tonsillitis are common presenting complaints in Primary Care and ENT setting. Tonsillitis accounts for between 5 and 10% of all cases of illness seen by the general practitioner. This has been a rather stable prevalence over the last 100 years or so (Collins, 1935). The analysis of the incidence by age shows, for both tonsillitis and sore throat, a relatively high incidence in childhood and young adults, while after that period there is a fall with age. Laryngitis, on the other hand, appears to occur more frequently among adults than among children. The incidence of tonsillitis, sore throat and other pharynx diseases is higher among females than males. There is no indication among school-age children that there is a higher incidence in women. There is a fairly regular seasonal variation in incidence as well, with higher incidence in winter and spring.Acute otitis media appears to be far more prevalent in children under the age of 10 and significantly less common from the third decade of live onwards. The UK was put into lockdown on 23 March 2020 in an unprecedented step to attempt to limit the spread of coronavirus. From an audit of over a total population of 9534 people, starting from the beginning of the lockdown to the 18 May 2020, the number of patients with diagnosis of tonsillitis was audited. The data were compared to those recorded in the 5 precedent five years during the very same period of time. Tonsillitis accounted, on average, for 8% of all cases of illness seen by the general practitioner from 2015 to 2019. The mean number of patients seen for tonsillitis was 805.8 with SD of 28.96. In 2020, the number of cases of tonsillitis was 593. From 2015 to 2020, the higher incidence in the female sex was confirmed from all the age bands>19. The greatest drop in cases was not recorded in the age group 0 to 9, but - in the order - 10 to 19, 20 to 29 and 30 to 39 with a reduction above the 30% in the first 2 age bands. Overall, the drop was seen across all the age bands (Cervoni, 2020).The same cannot be said for the diagnosis of acute otitis media in its various forms. To establish the impact of the lock-down on the diagnosis of acute otitis media, we audited a total population of 9534 people, starting from the beginning of the lock-down in March 2020, to the end of the phase 1 of the lock-down in May 2020, for the number of patients with diagnosis of AOM.  From 2015 to 2020, across the very same period of time, there has been a relatively stable prevalence with, perhaps, a slightly decreasing trend.The drop recorded during the pandemic does not reach statistical significance.Furthermore, differently from the diagnosis of tonsillitis, there is not obvious difference of incidence between males and females.  

Objective:Scapular and parascapular free tissue transfer (SFTT) is a well described reconstructive option for the head and neck. Majority of reported outcomes are of reconstruction of oromandibular and midface defects. The aim was to describe one institution’s experience with SFTT for reconstruction of PE defects. Design: Retrospective review of patients undergoing SFTT for head and neck defects between 2009 and 2014 at a tertiary medical center. The cohort included patients undergoing reconstruction of PE defects with at least 6 months follow up. Setting:Tertiary medical center Participants:Patients undergoing SFTT for PE defects. Seventeen patients (13 male and 4 female) met inclusion criteria. Main outcomes and Measures: Surgical outcomes, speech, voice outcomes, swallowing outcomes, enteral feeding and tracheoesophageal puncture usage. Results:Seventeen patients met criteria – 4 female, average age at time of surgery 64.5 (SD 9.1). Thirteen patients were Caucasian and remaining four African American. Two of 17 patients developed pharyngocutaneous fistulas (PCF) as inpatients. There was one major medical complication (pulmonary embolism) and 7 minor complications. Mean hospital length of stay was 15.7 days (SD 8.2). In post-operative setting, only one patient remained PEG-dependent, 11 patients supplemented oral intake with PEG feeds and 5 patients took nutrition solely by mouth. Four patients utilized written communication exclusively, 6 patients pursued TEP placement and 7 utilized electrolarynx. Conclusion:The SFTT is a viable option for hypopharyngeal reconstruction. All SFTT remained viable for the duration of our review. Post-operative PCF rate were comparable to that reported after laryngectomy.

Objectives To establish patient-reported outcome measures (PROM) on quality of life (QOL) for early stage floor of mouth carcinoma (FOM-CA) undergoing surgical resection and split thickness skin graft (STSG) reconstruction. Design Retrospective analysis with a validated questionnaire Setting Tertiary academic cancer center Participants Patients with pathologic stage T1/T2 FOM-CA who underwent resection and STSG reconstruction Main Outcome Measures University of Washington QOL (v4) questionnaire completed after at least 6 months since surgery Results 24 out of 49 eligible patients completed questionnaires with a mean follow up of 41 months (range: 6-88). Subsites of tumor involvement/resection included: 1) lateral FOM (L-FOM) (n = 17), 2) anterior FOM (A-FOM) (n = 4), and 3) alveolar ridge with FOM, all of whom underwent lateral marginal mandibulectomy (MM-FOM) (n = 3). All patients reported swallowing scores of 70 or better (“I cannot swallow certain solid foods”). 96% (23/24) reported speech of 70 or better (“difficulty saying some words, but I can be understood over the phone”). A-FOM patients reported worse chewing than L-FOM patients (mean: 50.0 vs. 85.3; p = 0.01). All four A-FOM patients reported a low chewing score of 50 (“I can eat soft solids but cannot chew some foods”). Otherwise, there were no significant differences between subsite groups in swallowing, speech, or taste. Conclusions STSG reconstructions for pathologic T1-T2 FOM-CA appear to result in reasonably high PROM QOL outcomes with the exception of A-FOM tumors having worse chewing outcomes.

The Facts COVID-19 is the disease associated with the 2019 novel coronavirus Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). The pandemic related to this virus has transformed life for billions of people across the globe. Using population based data from England, we recently showed a strong independent relation over time between our calculated R value for COVID-19 transmission and the number of cases identified as definitely positive in the population. We determined that 26.8% of the population of the United Kingdom (UK) possibly had been infected by late April 2020 approximating to 18.2 million people. Reflection Different modelling approaches give different answers to the question of how many people in the UK and elsewhere have actually been infected by COVID-19, which all would agree in epidemiological terms is behaving very differently from other Coronaviruses that we have seen in the past. We are learning more and more about this virus. National policy is changing rapidly and COIVD-19 antibody testing is increasingly being applied. This will facilitate better datasets from population based studies. The picture will become clearer as more data accrues over time.

Aims: To assess the appropriateness of the use and interpretation of subgroup analysis in haematology randomized clinical trials (RCT). Method: A systematic review of Medline including Haematology phase III RCT published between January 2013 and October 2019 was carried to identify subgroup analysis reported. Information related to trials characteristics, subgroup analysis reported and claims of subgroup difference were collected. Results: A total of 98 studies reporting subgroup analyses were identified. Of those, 24 RCT reported 46 claims of subgroup difference. Among them, 44 were claims for the primary outcome, of which 25 were considered strong claims and 17 were considered suggestions of a possible effect. Authors included subgroup variables for the primary outcome measured at baseline for 38 claims (n = 86.36%), used subgroup variable as stratification factor at randomization for 15 (34.09%), clearly prespecify their hypothesis for 11 (25%), the subgroup effect was one of a small number of hypothesised effects tested for 17 (38.36%), carried out a test of interaction that provide statistically significant for 18 (40.91%), documented replication of a subgroup effect with previously related studies for 11 (25%), identify consistency of a subgroup effect across related outcome for 10 (22.72%), and provided a biological rationale for the effect for 8 (18.18%). Of the 44 claims for the primary outcome, 34 (77.27%) met 4 or fewer of the 10 credibility criteria. Conclusion: Credibility of subgroup claims reported in haematology RCT lack of credibility, even when claims are strong. Information about subgroup difference should be interpreted ca

Background The adolescent and young adult (AYA) period is a time of high morbidity and mortality for persons with sickle cell disease (SCD). The goal of this study was to use implementation science combined with qualitative methods to understand the determinants of an optimal transition to adult care for AYA with SCD. Methods Sixty participants were purposefully recruited from a large hospital system and the community for 16 focus groups or semi-structured interviews. Patient-caregiver dyads and health care providers shared experiences in the health care and academic settings. Data were coded and analyzed by paired coders using an inductive coding approach in combination with an implementation research framework, the Consolidated Framework for Implementation Research (CFIR). Results At the Individual Characteristics level, AYA patients expressed challenges with adult life experiences, disease self-management, and preparation for the adult health care model. Caregivers and health care providers reported independence and autonomy as facilitators of a successful transition. At the Inner and Outer Setting levels, differences between pediatric and adult health care models were noted barriers, highlighting the gap in patient-centered care. Patient and provider communication was identified as both a barrier and facilitator. A standardized approach to transition planning and coordination was noted as a facilitator. At the Intervention Characteristics level, adaptability, incentive, and perceived attractiveness of the intervention were important components. Conclusion This study highlights which determinants of transition are most amenable to evidence-based interventions. This is imperative for rapidly improving this process for AYA with SCD and, thus, improving overall outcomes.

Introduction: Coronary artery fistula (CAF) is a rare cardiac anomaly that typically presents as a continuous murmur in an otherwise asymptomatic patient. Occasionally, it can result in congestive heart failure or bacterial endocarditis. Objective: To better delineate the course of coronary artery fistula for the first time, using the SonoVue contrast agent during transthoracic echocardiography. Method and results: A referred 46-year-old male with a known history of dyspnea on exertion for a period of almost three months was admitted to the hospital with progressive dyspnea, and assessed under suspicion of CAF. CAF, was seen with a coronary angiogram, but the exact entry point in the left ventricle or left atrial wall could not be determined. CT angiography also failed to establish the exact point of entrance to LV (left ventricle), so CAG (coronary angiography) was repeated with SonoVue contrast agent injected into LM (Left main) while using a Siemens echocardiography machine. Multiple views were obtained during the injection, and revealed unusual flow in the left ventricle just below the PML (posterior mitral leaflet) postero-lateral and passing through the fistula to LV. Conclusion: Contrast Enhanced Echocardiography is thought to be more sensitive and in affording an accurate delineation of CAF drainage into cardiac chambers, and can be utilized in a direct precise and safe way.

Testing and screening for factor deficiency using one-stage clotting assays is the most prevalent methodology, but it is susceptible to misestimating a patient’s true coagulable state due to either the clot detection methodology or the aPTT reagents involved. In our case report, a 16-year-old with mild hemophilia B had a normal aPTT and factor IX activity using a new platform in the clinical laboratory. We evaluated the impact of instrument and aPTT reagents that differed in clot detection methodology, the activator and the source of phospholipid in one stage assays (OSA) for FIX:C and aPTT using plasma from this patient.

The pandemic of the novel coronavirus disease, COVID-19 is having a serious impact on pediatric patients with cancer. Social distancing, self-quarantining and nationwide lockdown have resulted in restricted movements of patients and families across the country. This has made the optimum management of children with cancer difficult. In this clinical perspective, we discuss the issues related to COVID-19 and pediatric cancer and how we have attempted to optimize the treatment for our patients using telemedicine, reorganizing the day care services, triaging our patients and modifying their treatment plans, partnered with the NGOs and local medical centres to provide care to our patients.

Background: Pleuropulmonary blastoma (PPB) is a rare lung malignancy in children derived from mesenchyme. Single-cell RNA sequencing is used to explore the heterogeneity of tumors. Here, we used this technology to classify PPB subpopulations and predict their differentiation trajectory. Procedure: This study included 10 007 single cells from a girl with PPB. After choosing malignant tumor cells with an inferring copy number variation, we used non-negative matrix factorization and Seurat analysis to cluster the cells and divided the subgroups by their differentially expressed genes and Gene Ontology enrichment analysis. Additionally, pseudotime trajectory analysis of PPB was conducted with Monocle. Results: Tumor cells were divided into two major categories including muscle (DEShiTNNT1hiTNNI1hi) and cartilage (TWIST1hiHTRA1hiBMP4hi). In muscle lineage, satellite myogenic cells (PAX7hiMYF5hiMSChi), which were subdivided into more primitive FABP7hi one and later ITM2Ahi one, were the origin of muscle in PPB and gradually differentiated into myocytes (MYOGhiTTNhiMYL4hi). And in the cartilage lineage, SOX9hiPAX1hiPAX9hi prechondrocytes generated MGPhiOGNhi chondrocytes and DKK2hiTNMDhi chondrocytes. Conclusions: Our results demonstrated unrecognized heterogeneity in PPB at the single cell level and defined its muscle and cartilage subpopulations together with their trajectories, which would provide some basis for the molecular mechanism and treatment of PPB.

Dipeptide carboxamide bearing nitrobenzene sulphonamides offers new prospect towards the inhibition of hemoglobin degradation in erythrocytes by Plasmodium falciparum; a malaria parasite and glycosyl phosphatidyl inositol (GPI) pathway which controls the release of variable surface glycoprotein (VSG) from Trypanosoma brucei. Structural design carried out produced series of dipeptide carboxamide bearing p-nitrobenzene sulphonamide compounds formed by coupling isoleucine (Ileu) or leucine (Leu) bearing amine with p-nitrobenzene sulphonamide bearing Ileu or Leu. Variation of coupling sequence between amidated amino acids and p-nitrobenzene sulphonamide bearing amino acid generates a library of 52 amidated Leu-Ileu dipeptide carboxamides bearing p-nitrobenzene sulphonamide compounds. Antimicrobial properties were evaluated using in-silico molecular docking. Protein residues E.coli (coded: 5MMN), plasmepsin (coded: 3QSI), trypanosome brucei dihydrofolate reductase pyrimethamine (coded: 3QFX) and prostaglandin synthese (coded: 1EQG) were generated from protein data base and was used to study biological activities of the compounds on bacterial, malarial, trypanosomiasis and analgesic parasites respectively. Ofloxacin, celecoxib, chloroquine and melarsoprol were used for docking studies as reference drugs for antibacterial, analgesic, antimalarial and antitrypanosomiasis respectively. Selected compounds from docking studies were examined using ADMET to ascertain their toxicity profile. Results of the antimicrobial properties reveal that some of the compounds showed better binding affinity on plasmepsin and trypanosome brucei parasites compared to standard drug used as reference in the docking studies, making them a potential drug candidates for malaria and trypanosomiasis treatment.

Introduction: We aim to determine the influence of lower gastrointestinal bleeding (LGIB) on mortality, morbidity, length of hospital stay, and resource utilization in end-stage renal disease (ESRD) patients. Material and Methods: The National Inpatient Sample database (2016 &2017) was used for data analysis using the International Classification of Diseases, Tenth Revision codes to identify the patients with the principal diagnosis of ESRD and LGIB. We assessed the all-cause in-hospital mortality, morbidity, predictors of mortality, length of hospital stay (LOS), and total costs between propensity-matched groups of ESRD patients with LGIB versus ESRD patients. Results: We identified 2187954 ESRD patients, of whom 242075 has LGIB, and 1945879 were ESRD patients. The in-hospital mortality was higher in ESRD with LGIB (OR 2.5, 95% CI 1.5-2.2; P=0.00). ESRD with LGIB has higher odds of mechanical ventilation (OR 1.4, 95% CI 6.4-16.4; P=0.00), and shock requiring vasopressor (OR 1.2, 95% CI 4.9-5.4; P=0.002). Advanced age (OR 1.02 CI 1.02-1.03 P=0.00), anemia (OR 1.04 CI 1.59-1.91 P=0.006), acute coronary syndrome (OR 1.8 CI 1.6-2.1, P=0.00), acute respiratory failure (OR 1.29 CI 2.0-2.6, P=0.00), mechanical ventilation (OR 1.9, CI 3.5-4.4, P=0.00), and sepsis (OR 1.5, CI 4.1-5.08, P=0.00) were identified as predictors of mortality in ESRD with LGIB. Mean LOS (10.8±14.9 vs. 6.3±8.5, P<0.01) and mean total charges (37054 $ vs. 18080 $, P<0.01) were also higher. Conclusions: In this propensity-matched analysis, ESRD with LGIB was associated with higher odds of in-hospital mortality, mechanical ventilation, and shock requiring vasopressor. Mean LOS and resource utilization were also higher.

Frontline Experience against COVID-19 in a Tertiary Obstetrics and Gynaecology Hospital: A commentaryAllison Tan CS1, Lily Kho CL1, Tan Shu Qi1, Rajeswari Kathirvel 1,2, Suzanna Sulaiman1,21Department of Obstetrics and Gynaecology, KK Women’s and Children’s Hospital, Singapore2Lee Kong Chian school of Medicine, Yong Loo Lin School of Medicine and Duke NUS, SingaporeCorresponding author: Dr Lily Kho CLEmail address: kho.chye.lee@singhealth.com.sgCorrespondence: Dr Lily Kho CL, Associate Consultant, Department of Obstetrics and Gynaecology, KK Women’s and Children’s Hospital, 100 Bukit Timah Road, Singapore 229899

The coronavirus pandemic caused global devastation and put unprecedented pressure on health care facilities world-wide. The response to the pandemic differed across the world as countries faced different challenges. Due to the novelty of this virus and its global effects, published guidance is currently limited to best practice and small-scale trials, however, globally, large-scale clinical trials are now underway. This review summarises the international response to coronavirus with respect to gynaecological oncology and suggests potential interventions to limit its spread during a resurgence or in the event of a future global pandemic.

The recombinant in vitro translation system known as the PURE system has been used in a variety of cell-free experiments such as expression of native and de novo proteins as well as various display methods to select for functional polypeptides. We developed a refined PURE-based display method for the preparation of stable mRNA and cDNA-peptide conjugates and validated its utility for in vitro selection. Our conjugate formation efficiency exceeded 40%, followed by gel purification to allow minimum carry-over of components from the translation system to the downstream assay enabling clean and efficient random peptide sequence screening. As a proof-of-concept, we chose the commercially available anti-FLAG M2 antibody as a target molecule for validation. Starting from approximately 1.7 x 1012 random sequences, a round-by-round high-throughput sequencing showed clear enrichment of the FLAG epitope DYKDDD as well as revealing consensus FLAG binding motif DYK(D/L/N)(L/Y/D/N/F)D. Enrichment of core FLAG motifs lacking one of the four key residues (DYKxxD) indicates that Tyr (Y) and Lys (K) appear as the two key residues essential for binding. Furthermore, comparison between mRNA display and cDNA display method resulted in overall similar performance with slightly higher enrichment for mRNA display. The consistency of two different display methods achieved by commercially available PURE system will be useful for future studies to explore sequence and functional space of diverse polypeptides.

Respiratory failure is a common cause of death. It is proven that Extracorporeal Membrane Oxygenation (ECMO) cannulation is successful in bridging patients to lung transplantation. Here we report on a 51-year-old patient with COPD who was bridged successfully to lung transplantation using venous-venous ECMO with a Protek Duo RD™ dual lumen cannula; which contributed to our success in bridging to transplant without the need for anticoagulation. Here we confirm that the clinical application use of the cannula without IV Heparin use is safe and feasible.

Background: Controversy exists regarding durability and survival after mitral valve repair between sternotomy and a small right anterior thoracotomy approaches. Methods: Between February 2004 and July 2015, 410 patients underwent mitral valve repair via either sternotomy (ST, n=135) or small right anterior thoracotomy (RAT, n=275). Mean follow up was 72.7  38.9 months. Postoperative echocardiograms were obtained in 310 patients (75.6%) at a mean of 20.3  21.4 months. Results: Overall survival at 1, 3, 5, and 10 years were 96.3, 93.0, 93.0, and 91.4% for the ST group and 99.3, 98.9, 98.4, and 97.0% for the RAT group (Log-Rank p = 0.004). There was no difference between groups in the cumulative incidence of need for mitral valve reoperation or progression of mitral regurgitation (MR) considering death as a competing outcome over time (p=0.94 and 0.53, respectively). Propensity score weighted multivariate Cox Proportional hazard modeling built on baseline differences between the RAT and ST groups, showed presence or absence of posterior or anterior leaflet pathology was not associated with mortality, need for reoperation, or progression of MR. A RAT approach was associated with a decreased mortality on adjusted analysis (hazard ratio, 0.32, 95% confidence interval, 0.13-0.82, p=0.018), however, this result was less significant when those with coronary artery disease were removed (hazard ratio, 0.34, 95% confidence interval, 0.12-0.96, p=0.041). Conclusions: Mitral valve repair via a small right anterior thoracotomy incision in select patients can be performed with surgical results and survival that are equivalent to the sternotomy approach.

Background: Sutureless bioprothesis aortic valves simplify surgery for aortic valve replacement (AVR) but some anatomical features of the recipients aortic annulus might preclude anchoring and lead to paravalvular leak. Sub-commissural annuloplasty (SCAP) has been sporadically proposed to secure implantation under these circumstances. This study evaluated whether SCAP affects early postoperative outcomes after sutureless Perceval-S implantation. Methods: We included all patients who underwent AVR (isolated or combined with coronary bypass) with the Perceval-S valve from March 2016 to August 2019. SCAP was performed each time the surgeon deemed it useful to improve anchoring, including after primary implantation failure. Results: One hundred and three patients were included. Mean age was 73.9±7.2 years and 36(35%) were women. SCAP was performed in 34(33%) patients, significantly more frequently in patients with large aortic annulus or bicuspid aortic valve. Perceval-S implantation was successful in 100(97%) patients and SCAP allowed successful redeployment of the same Perceval S valve in 4(28%) of first implantation failures. Thirty-day mortality was 2% (n=2), of which one was related to the procedure. There was no significant difference in the incidence of postoperative conduction disorders between patients with and without SCAP (respectively, 3[9%] vs 7[10%], p=1.0). More than trivial paravalvular leak was noted in 1(1%) patient without SCAP. Postoperative peak and mean pressure gradients were lower in patients with than in those without SCAP (respectively, 19.0±7.9 mmHg vs 23.1±7.0 mmHg, p=0.001; and 10.4±4.1 versus 12.6±3.7 mmHg, p=0.001). Conclusions: SCAP is a safe, simple and reproducible technique that might facilitate Perceval-S aortic valve implantation.

The oleaginous yeast Yarrowia lipolytica is an important industrial microorganism used for the production of lipids, proteins and various chemicals. The design of effective biotechnological processes with this cell factory requires an in-depth knowledge of its metabolism. Here we present a transcriptomic study of Y. lipolytica grown in the presence of two important carbon sources, namely glycerol and glucose, as well as in a mixture of both at different carbon to nitrogen ratios. It emerged that the transcriptomic landscape of Y. lipolytica is more sensitive to the nitrogen availability than to the utilized carbon source, as evidenced by more genes being differentially expressed in lower carbon to nitrogen ratio. In particular, expression of hexokinase (HXK1) is significantly susceptible to changes in nitrogen concentrations. Moreover, high HXK1 expression in low nitrogen seems to impact the expression of other genes which are implicated in tricarboxylic acid cycle and erythritol biosynthesis. We further show that expression of HXK1 and two genes belonging to the sugar porter family might be controlled by GATA-like zinc-finger proteins.

1. Fire and frost represent two major hurdles for the persistence of trees in open grassy biomes and have both been proposed as drivers of grassland-forest boundaries in Africa. 2. We assess the response of young tree seedlings, which represent a vulnerable stage in tree recruitment, to traumatic fire and frost disturbances. 3. In a greenhouse experiment, we investigated how seedling traits predicted survival and resprouting ability in response to fire vs frost; we characterised survival strategies of seedlings in response to the two disturbances, and we documented how the architecture of surviving seedlings is affected by fire vs frost injury. 4. Survival rates were similar under both treatments. However, different species displayed different levels of sensitivity to fire and frost. Seedling survival was higher for older seedlings and seedlings with more basal leaves. Survivors of a fire event lost more biomass than the survivors of a frost event. However, the architecture of recovered fire and frost treated seedlings were mostly similar. Seedlings that recovered from fire and frost treatments were often shorter than those that had not been exposed to any disturbance, with multiple thin branches, which may increase vulnerability to the next frost or fire event. 5. Synthesis. Fire caused more severe aboveground damage compared to frost, suggesting that trees in these open grassland systems may be subjected to a seedling release bottleneck maintained by fire. However, the woody species composition will almost certainly be influenced by phenomena that affect the timing and frequency of seedling exposure to damage, as mortality was found to be dependent on seedling age. Therefore, changes in fire regime and climate (esp. changes that bring about less frost and reduced fire intensity and frequency) are likely to result in changes in the composition and the structure of the woody components of these systems.

The whitefly Bemisia tabaci is a closely related group of > 35 cryptic species that feed on the phloem sap of a broad range of host plants. Species in the complex differ in their host-range breadth, but the mechanisms involved remain poorly understood. We investigated, therefore, how six different B. tabaci species cope with the environmental unpredictability presented by a set of four common and novel host plants. Behavioural studies indicated large differences in performances on the four hosts and putative specialization of one of the species to cassava plants. Transcriptomic analyses revealed two main insights. First, a large set of genes involved in metabolism (> 85%) showed differences in expression between the six species, and each species could be characterized by its own unique expression pattern of metabolic genes. However, within species, these genes were constitutively expressed, with a low level of environmental responsiveness (i.e., to host change). Second, within each species, sets of genes mainly associated with the super-pathways “environmental information processing” and “organismal systems”, responded to the host switching events. These included genes encoding for proteins involved in sugar homeostasis, signal transduction, membrane transport and immune, endocrine, sensory and digestive responses. Our findings suggested that the six B. tabaci species can be divided into four performance/transcriptomic “Types” and that polyphagy can be achieved in multiple ways. However, polyphagy level is determined by the specific identity of the metabolic genes/pathways that are enriched and overexpressed in each species (the species’ individual metabolic “tool kit”).

Suggested Time: 50 minutes