Accommodating unobservability to control flight attitude with optic flow.

Attitude control is an essential flight capability. Whereas flying robots commonly rely on accelerometers1 for estimating attitude, flying insects lack an unambiguous sense of gravity2,3. Despite the established role of several sense organs in attitude stabilization3-5, the dependence of flying insects on an internal gravity direction estimate remains unclear. Here we show how attitude can be extracted from optic flow when combined with a motion model that relates attitude to acceleration direction. Although there are conditions such as hover in which the attitude is unobservable, we prove that the ensuing control system is still stable, continuously moving into and out of these conditions. Flying robot experiments confirm that accommodating unobservability in this manner leads to stable, but slightly oscillatory, attitude control. Moreover, experiments with a bio-inspired flapping-wing robot show that residual, high-frequency attitude oscillations from flapping motion improve observability. The presented approach holds a promise for robotics, with accelerometer-less autopilots paving the road for insect-scale autonomous flying robots6. Finally, it forms a hypothesis on insect attitude estimation and control, with the potential to provide further insight into known biological phenomena5,7,8 and to generate new predictions such as reduced head and body attitude variance at higher flight speeds9.

Virus-assisted directed evolution of enhanced suppressor tRNAs in mammalian cells.

Site-specific incorporation of unnatural amino acids (Uaas) in living cells relies on engineered aminoacyl-transfer RNA synthetase-tRNA pairs borrowed from a distant domain of life. Such heterologous suppressor tRNAs often have poor intrinsic activity, presumably due to suboptimal interaction with a non-native translation system. This limitation can be addressed in Escherichia coli using directed evolution. However, no suitable selection system is currently available to do the same in mammalian cells. Here we report virus-assisted directed evolution of tRNAs (VADER) in mammalian cells, which uses a double-sieve selection scheme to facilitate single-step enrichment of active yet orthogonal tRNA mutants from naive libraries. Using VADER we developed improved mutants of Methanosarcina mazei pyrrolysyl-tRNA, as well as a bacterial tyrosyl-tRNA. We also show that the higher activity of the most efficient mutant pyrrolysyl-tRNA is specific for mammalian cells, alluding to an improved interaction with the unique mammalian translation apparatus.

MicroRNA-409-3p/BTG2 signaling axis improves impaired angiogenesis and wound healing in obese mice.

Wound healing is facilitated by neoangiogenesis, a complex process that is essential to tissue repair in response to injury. MicroRNAs are small, noncoding RNAs that can regulate the wound healing process including stimulation of impaired angiogenesis that is associated with type-2 diabetes (T2D). Expression of miR-409-3p was significantly increased in the nonhealing skin wounds of patients with T2D compared to the non-wounded normal skin, and in the skin of a murine model with T2D. In response to high glucose, neutralization of miR-409-3p markedly improved EC growth and migration in human umbilical vein endothelial cells (HUVECs), promoted wound closure and angiogenesis as measured by increased CD31 in human skin organoids, while overexpression attenuated EC angiogenic responses. Bulk mRNA-Seq transcriptomic profiling revealed BTG2 as a target of miR-409-3p, where overexpression of miR-409-3p significantly decreased BTG2 mRNA and protein expression. A 3' untranslated region (3'-UTR) luciferase assay of BTG2 revealed decreased luciferase activity with overexpression of miR-409-3p, while inhibition had opposite effects. Mechanistically, in response to high glucose, miR-409-3p deficiency in ECs resulted in increased mTOR phosphorylation, meanwhile BTG-anti-proliferation factor 2 (BTG2) silencing significantly decreased mTOR phosphorylation. Endothelial-specific and tamoxifen-inducible miR-409-3p knockout mice (MiR-409IndECKO ) with hyperglycemia that underwent dorsal skin wounding showed significant improvement of wound closure, increased blood flow, granulation tissue thickness (GTT), and CD31 that correlated with increased BTG2 expression. Taken together, our results show that miR-409-3p is a critical mediator of impaired angiogenesis in diabetic skin wound healing.

Effector loss drives adaptation of Pseudomonas syringae pv. actinidiae biovar 3 to Actinidia arguta.

A pandemic isolate of Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) has devastated kiwifruit orchards growing cultivars of Actinidia chinensis. In contrast, A. arguta (kiwiberry) is not a host of Psa3. Resistance is mediated via effector-triggered immunity, as demonstrated by induction of the hypersensitive response in infected A. arguta leaves, observed by microscopy and quantified by ion-leakage assays. Isolates of Psa3 that cause disease in A. arguta have been isolated and analyzed, revealing a 51 kb deletion in the exchangeable effector locus (EEL). This natural EEL-mutant isolate and strains with synthetic knockouts of the EEL were more virulent in A. arguta plantlets than wild-type Psa3. Screening of a complete library of Psa3 effector knockout strains identified increased growth in planta for knockouts of four effectors-AvrRpm1a, HopF1c, HopZ5a, and the EEL effector HopAW1a -suggesting a resistance response in A. arguta. Hypersensitive response (HR) assays indicate that three of these effectors trigger a host species-specific HR. A Psa3 strain with all four effectors knocked out escaped host recognition, but a cumulative increase in bacterial pathogenicity and virulence was not observed. These avirulence effectors can be used in turn to identify the first cognate resistance genes in Actinidia for breeding durable resistance into future kiwifruit cultivars.

A Genetically Encoded Photocaged Cysteine for Facile Site-Specific Introduction of Conjugation-Ready Thiol Residues in Antibodies.

Antibody-drug conjugates (ADCs) have emerged as a powerful class of anticancer therapeutics that enable the selective delivery of toxic payloads into target cells. There is increasing appreciation for the importance of synthesizing such ADCs in a defined manner where the payload is attached at specific permissive sites on the antibody with a defined drug to antibody ratio. Additionally, the ability to systematically alter the site of attachment is important to fine-tune the therapeutic properties of the ADC. Engineered cysteine residues have been used to achieve such site-specific programmable attachment of drug molecules onto antibodies. However, engineered cysteine residues on antibodies often get "disulfide-capped" during secretion and require reductive regeneration prior to conjugation. This reductive step also reduces structurally important disulfide bonds in the antibody itself, which must be regenerated through oxidation. This multistep, cumbersome process reduces the efficiency of conjugation and presents logistical challenges. Additionally, certain engineered cysteine sites are resistant to reductive regeneration, limiting their utility and the overall scope of this conjugation strategy. In this work, we utilize a genetically encoded photocaged cysteine residue that can be site-specifically installed into the antibody. This photocaged amino acid can be efficiently decaged using light, revealing a free cysteine residue available for conjugation without disrupting the antibody structure. We show that this ncAA can be incorporated at several positions within full-length recombinant trastuzumab and decaged efficiently. We further used this method to generate a functional ADC site-specifically modified with monomethyl auristatin F (MMAF).

Precise Manipulation of the Site and Stoichiometry of Capsid Modification Enables Optimization of Functional Adeno-Associated Virus Conjugates.

The ability to engineer adeno-associated virus (AAV) vectors for targeted transduction of specific cell types is critically important to fully harness their potential for human gene therapy. A promising approach to achieve this objective involves chemically attaching retargeting ligands onto the virus capsid. Site-specific incorporation of a bioorthogonal noncanonical amino acid (ncAA) into the AAV capsid proteins provides a particularly attractive strategy to introduce such modifications with exquisite precision. In this study, we show that using ncAA mutagenesis, it is possible to systematically alter the attachment site of a retargeting ligand (cyclic-RGD) on the AAV capsid to create diverse conjugate architectures and that the site of attachment heavily impacts the retargeting efficiency. We further demonstrate that the performance of these AAV conjugates is highly sensitive to the stoichiometry of capsid labeling (labels per capsid), with an intermediate labeling density providing optimal activity for cRGD-mediated retargeting. Finally, we developed a technology to more precisely control the number of attachment sites per AAV capsid by selectively incorporating an ncAA into the minor capsid proteins with high fidelity and efficiency, such that AAV conjugates with varying stoichiometry can be synthesized. Together, this platform provides unparalleled control over the site and stoichiometry of capsid modification, which will enable the development of next-generation AAV vectors tailored with desirable attributes.

NbPTR1 confers resistance against Pseudomonas syringae pv. actinidiae in kiwifruit.

Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) causes a devastating canker disease in yellow-fleshed kiwifruit (Actinidia chinensis). The effector HopZ5, which is present in all isolates of Psa3 causing global outbreaks of pandemic kiwifruit canker disease, triggers immunity in Nicotiana benthamiana and is not recognised in susceptible A. chinensis cultivars. In a search for N. benthamiana nonhost resistance genes against HopZ5, we found that the nucleotide-binding leucine-rich repeat receptor NbPTR1 recognised HopZ5. RPM1-interacting protein 4 orthologues from N. benthamiana and A. chinensis formed a complex with NbPTR1 and HopZ5 activity was able to disrupt this interaction. No functional orthologues of NbPTR1 were found in A. chinensis. NbPTR1 transformed into Psa3-susceptible A. chinensis var. chinensis 'Hort16A' plants introduced HopZ5-specific resistance against Psa3. Altogether, this study suggested that expressing NbPTR1 in Psa3-susceptible kiwifruit is a viable approach to acquiring resistance to Psa3 and it provides valuable information for engineering resistance in otherwise susceptible kiwifruit genotypes.

CDKN2A/B deletion in IDH-mutant astrocytomas: An evaluation by Fluorescence in-situ hybridization.

INTRODUCTION: CDKN2A/B homozygous deletion is one of the defining features of grade 4 in IDH-mutant astrocytic tumours. AIM: To evaluate CDKN2A/B-deletion in IDH-mutant astrocytic tumours and its clinicopathological impact. MATERIALS AND METHODS: CDKN2A/B-deletion was evaluated by Fluorescence in-situ hybridisation (FISH) and interpreted by two recently accepted methods. RESULTS: Eighty-three out of 94 cases (histologically-grade 2: 3, grade 3: 46, grade 4: 34) were interpretable on FISH. Concordant CDKN2A/B-deletion was observed in 71% (27/38) of lower-grade tumours (n = 49) and 90% (27/30) of histological grade 4 tumours (n = 34). Both the interpretation methods showed good agreement (Kappa = 0.75). CDKN2A/B-deletion showed an inverse correlation for < 10% MIB-1 labeling index (p = 0.01) while that by method-2 showed a significant correlation for grade 4 (p = 0.02). No significant correlation was observed for any other clinicopathological parameters. Twenty-four patients showed progression/recurrence (including deaths), and no significant difference in frequency of CDKN2A/B deletion was observed among cases with disease progression across different histological grades. CONCLUSIONS: CDKN2A/B-deletion was observed across all the histological grades of IDH-mutant astrocytic tumours, expectedly more in the higher grade. FISH, as a method, can be used for the detection of CDKN2A/B homozygous deletion, when there is concordant interpretation.

The Benefit of Cost-Transparency Calculators Does Not Extend to Vascular Surgery Patients.

BACKGROUND: In 2021, the Centers for Medicare & Medicaid Services (CMS) mandated that every hospital create a publicly available webtool for pricing various medical services in an effort to give patients transparency in regard to their health care expenses and allow patients to "shop around" to receive the care most fitting their budget. Our objective is to investigate the utility this mandate provides for vascular surgery patients. METHODS: Standardized searches were performed to find patient cost calculators for Newsweek's Top 50 Hospitals in the United States. If the webtool was found, a list of standardized searches were performed to investigate whether the tool listed prices for the following vascular procedures: Arteriovenous fistula (AVF), varicose vein procedures, and Endovascular Aneurysm Repair (EVAR). RESULTS: Of the 50 hospitals included, all had an easily accessible web-based cost estimator tool. The average time to find the cost estimator was 33.27 sec. Of these 50 hospitals, 10% provided cost information on AVF surgery, 12% provided cost information on varicose vein procedures, and 0% provided information on EVAR. There was no difference in the hospital's likelihood to report a price based on region of the United States. Average preinsurance price for AVF surgery was $11,933.61 and $22,191 for vein procedures. CONCLUSIONS: In conclusion, despite good adherence to the CMS mandate requiring a publicly available pricing tool, these tools provide little to no information for vascular surgery patients. Overall, this discrepancy places vascular surgery patients at a significant disadvantage. As such, vascular patients do not have access to the knowledge necessary to financially prepare for surgery, and furthermore, they are not afforded the luxury to choose where to have procedures performed based on price variability. Hopefully this research will encourage hospitals to broaden the scope of their cost calculators to allow it to benefit all patients.

Societal shifts due to COVID-19 reveal large-scale complexities and feedbacks between atmospheric chemistry and climate change.

The COVID-19 global pandemic and associated government lockdowns dramatically altered human activity, providing a window into how changes in individual behavior, enacted en masse, impact atmospheric composition. The resulting reductions in anthropogenic activity represent an unprecedented event that yields a glimpse into a future where emissions to the atmosphere are reduced. Furthermore, the abrupt reduction in emissions during the lockdown periods led to clearly observable changes in atmospheric composition, which provide direct insight into feedbacks between the Earth system and human activity. While air pollutants and greenhouse gases share many common anthropogenic sources, there is a sharp difference in the response of their atmospheric concentrations to COVID-19 emissions changes, due in large part to their different lifetimes. Here, we discuss several key takeaways from modeling and observational studies. First, despite dramatic declines in mobility and associated vehicular emissions, the atmospheric growth rates of greenhouse gases were not slowed, in part due to decreased ocean uptake of CO2 and a likely increase in CH4 lifetime from reduced NO x emissions. Second, the response of O3 to decreased NO x emissions showed significant spatial and temporal variability, due to differing chemical regimes around the world. Finally, the overall response of atmospheric composition to emissions changes is heavily modulated by factors including carbon-cycle feedbacks to CH4 and CO2, background pollutant levels, the timing and location of emissions changes, and climate feedbacks on air quality, such as wildfires and the ozone climate penalty.

Oncoplastic Surgery Outcomes in the Older Breast Cancer Population: A Matched-Cohort Comparison Study.

BACKGROUND: Oncoplastic breast surgery (OBS) is a form of breast conservation surgery (BCS) that involves a partial mastectomy followed by immediate volume displacement or volume replacement surgical techniques. To date, there are few studies evaluating OBS in older patients. Therefore, we sought to determine if outcomes differed between patients 65 years and older versus younger patients who underwent oncoplastic surgical procedures. METHODS: A retrospective chart review was performed for all oncoplastic breast operations within a single health system from 2015 to 2021. Patients were stratified by age, with patients 65 years and older (OBS65+) identified and then matched with younger patients (OBS <65) based on BMI. Primary outcomes were positive margin rates and overall complication rates; secondary outcomes were locoregional recurrence (LR), distant recurrence (DR), disease-free survival (DFS), overall survival (OS), and long-term breast asymmetry. RESULTS: A total of 217 patients underwent OBS over the 6-year period, with 22% being OBS65+. Preoperatively, older patients experienced higher American Anesthesia (ASA) scores, Charlson Co-morbidity index (CCI) scores, and higher rates of diabetes mellitus, hypertension, and grade 3 breast ptosis. Despite this, no significant differences were found between primary or secondary outcomes compared to younger patients undergoing the same procedures. CONCLUSIONS: Oncoplastic breast reconstruction is a safe option in patients 65 years and older, with overall similar recurrence rates, positive margin rates, and survival when compared to younger patients. Although the older cohort of patients had greater preoperative risk, there was no difference in overall surgical complication rates or outcomes. Supporting the argument that all oncoplastic breast reconstruction techniques should be offered to eligible patients, irrespective of age.

Enhanced Directed Evolution in Mammalian Cells Yields a Hyperefficient Pyrrolysyl tRNA for Noncanonical Amino Acid Mutagenesis.

Heterologous tRNAs used for noncanonical amino acid (ncAA) mutagenesis in mammalian cells typically show poor activity. We recently introduced a virus-assisted directed evolution strategy (VADER) that can enrich improved tRNA mutants from naïve libraries in mammalian cells. However, VADER was limited to processing only a few thousand mutants; the inability to screen a larger sequence space precluded the identification of highly active variants with distal synergistic mutations. Here, we report VADER2.0, which can process significantly larger mutant libraries. It also employs a novel library design, which maintains base-pairing between distant residues in the stem regions, allowing us to pack a higher density of functional mutants within a fixed sequence space. VADER2.0 enabled simultaneous engineering of the entire acceptor stem of M. mazei pyrrolysyl tRNA (tRNAPyl ), leading to a remarkably improved variant, which facilitates more efficient incorporation of a wider range of ncAAs, and enables facile development of viral vectors and stable cell-lines for ncAA mutagenesis.

Chemical Tagging of Bioactive Amides by Cooperative Catalysis: Applications in the Syntheses of Drug Conjugates.

We disclose a practical catalytic method for arming bioactive amide-based natural products and other small-molecule drugs with various functional handles for the synthesis of drug conjugates. We demonstrate that a set of readily available Sc-based Lewis acids and N-based Brønsted bases can function cooperatively to deprotonate amide N-H bonds in polyfunctional drug molecules. An aza-Michael reaction between the resulting amidate and α,ß-unsaturated compounds produces an array of drug analogues that are equipped with an alkyne, azide, maleimide, tetrazine, or diazirine moiety under redox and pH-neutral conditions. The utility of this chemical tagging strategy is showcased through the production of drug conjugates by the click reaction between the alkyne-tagged drug derivatives and an azide-containing green fluorescent protein, nanobody, or antibody.

Fluorosulfate as a Latent Sulfate in Peptides and Proteins.

Sulfation widely exists in the eukaryotic proteome. However, understanding the biological functions of sulfation in peptides and proteins has been hampered by the lack of methods to control its spatial or temporal distribution in the proteome. Herein, we report that fluorosulfate can serve as a latent precursor of sulfate in peptides and proteins, which can be efficiently converted to sulfate by hydroxamic acid reagents under physiologically relevant conditions. Photocaging the hydroxamic acid reagents further allowed for the light-controlled activation of functional sulfopeptides. This work provides a valuable tool for probing the functional roles of sulfation in peptides and proteins.

Superficial and functional imaging of the tricipital lymphatic pathway: a modern reintroduction.

PURPOSE: The tricipital, or Caplan's, lymphatic pathway has been previously identified in cadavers and described as a potential compensatory pathway for lymphatic drainage of the upper extremity, as it may drain lymphatic fluid directly to the scapular lymph nodes, avoiding the axillary lymph node groups. The aim of this study was to map the anatomy of the tricipital pathway in vivo in patients without lymphatic disease. METHODS: A retrospective review was performed to identify patients with unilateral breast cancer undergoing preoperative Indocyanine green (ICG) lymphography prior to axillary lymph node dissection from May 2021 through January 2022. Exclusion criteria were evidence or known history of upper extremity lymphedema or non-linear channels visualized on ICG. Demographic, oncologic, and ICG imaging data were extracted from a Lymphatic Surgery Database. The primary outcome of this study was the presence and absence of the tricipital pathway. The secondary outcome was major anatomical variations among those with a tricipital pathway. RESULTS: Thirty patients underwent preoperative ICG lymphography in the study period. The tricipital pathway was visualized in the posterior upper arm in 90% of patients. In 63% of patients, the pathway had a functional connection to the forearm (long bundle variant) and in 27%, the pathway was isolated to the upper arm without a connection to the forearm (short bundle variant). In those with a long bundle, the contribution was predominantly from the posterior ulnar lymphosome. Anatomic destinations of the tricipital pathway included the deltotricipital groove and the medial upper arm channel, which drains to the axilla. CONCLUSION: When present, the tricipital pathway coursed along the posterior upper arm with variability in its connections to the forearm distally, and the torso proximally. Long-term follow-up studies will help determine the significance of these anatomic variations in terms of individual risk of lymphedema after axillary nodal dissection.

Post-Mastectomy Tissue Expander Placement Followed by Radiation Therapy: A Cost-Effectiveness Analysis of Staged Autologous Versus Implant-Based Unilateral Reconstruction.

BACKGROUND: There is no preferred approach to breast reconstruction for patients with locally advanced breast cancer (LABC) who require post-mastectomy radiation therapy (PMRT). Staged implant and autologous reconstruction both have unique risks and benefits. No previous study has compared their cost-effectiveness with utility scores. METHODS: A literature review determined the probabilities and outcomes for mastectomy and staged implant or autologous reconstruction. Utility scores were used to calculate the quality-adjusted life years (QALYs) associated with successful surgery and postoperative complications. Medicare billing codes were used to assess costs. A decision analysis tree was constructed with rollback and incremental cost-effectiveness ratio (ICER) analyses. Sensitivity analyses were performed to validate results and account for uncertainty. RESULTS: Mastectomy with staged deep inferior epigastric perforator (DIEP) flap reconstruction is costlier ($14,104.80 vs $3216.93), but more effective (QALYs, 29.96 vs 24.87). This resulted in an ICER of 2141.00, favoring autologous reconstruction. One-way sensitivity analysis showed that autologous reconstruction was more cost-effective if less than $257,444.13. Monte Carlo analysis showed a confidence of 99.99% that DIEP flap reconstruction is more cost-effective. CONCLUSIONS: For patients with LABC who require PMRT, staged autologous reconstruction is significantly more cost-effective than reconstruction with implants. Despite the decreased morbidity, staged implant reconstruction has greater rates of complication.

Variable Accessibility to Consumer Pricing Among Breast Cancer Operations.

BACKGROUND: The Centers for Medicare & Medicaid Services (CMS) mandate that every US hospital provide public online pricing information for services rendered. This allows patients to compare prices across hospital systems before establishing care. The goal of this project was to evaluate hospital compliance and patient-level accessibility to price transparency for common breast cancer surgical procedures. METHODS: A sample case of a 62-year-old female with a T2N0 breast cancer was chosen. The patient would have the option of undergoing a partial mastectomy or mastectomy, both with sentinel lymph node biopsy (SLNB). Eight Massachusetts academic medical centers were evaluated. Searches were performed by authors for each hospital system and procedure using the sample case. RESULTS: Every hospital had a cost calculator on its website. The average success rate of establishing a cost for partial mastectomy, mastectomy, and SLNB was 58, 35, and 25%, respectively. The median time to reach the cost calculator tool was 32 s (range 25-37 s). In successful attempts, the median pre-insurance estimated cost of a partial mastectomy was $16,509 (range $11,776-22,169), compared with $24,541 (range $16,921-25,543) for mastectomy and $12,342 (range $4034-20,644) for SLNB. SLNB costs varied significantly across hospitals (p = 0.025), but no statistically significant difference was observed for partial mastectomy or mastectomy. CONCLUSION: Despite new regulatory requirements by CMS for increased price transparency for surgical procedures, our results demonstrate poor success rates in obtaining cost estimates and significant variability of reported hospital charges. Further efforts to improve the quality of hospital cost estimate calculators are necessary for informed decision-making for patients with breast cancer.

External Validation of the Breast Cancer Surgery Risk Calculator (BCSRc): A Predictive Model for Postoperative Complications.

BACKGROUND: The breast cancer surgical risk calculator (BCSRc) is a prognostic tool that determines a breast cancer patient's unique risk of acute complications following each possible surgical intervention. When used in the preoperative setting, it can help to stratify patients with an increased complication risk and enhance the patient-physician informed decision-making process. The objective of this study was to externally validate the four models used in the BCSRc on a large cohort of patients who underwent breast cancer surgery. METHODS: The BCSRc was developed by using a retrospective cohort from the National Surgical Quality Improvement Program database from 2005 to 2018. Four models were built by using logistic regression methods to predict the following composite outcomes: overall, infectious, hematologic, and internal organ complications. This study obtained a new cohort of patients from the National Surgical Quality Improvement Program by utilizing participant user files from 2019 to 2020. The area under the curve, brier score, and Hosmer-Lemeshow goodness of fit test measured model performance, accuracy, and calibration, respectively. RESULTS: A total of 192,095 patients met inclusion criteria in the development of the BCSRc, and the validation cohort included 60,144 women. The area under the curve during external validation for each model was approximately 0.70. Accuracy, or Brier scores, were all between 0.04 and 0.003. Model calibration using the Hosmer-Lemeshow statistic found all p-values > 0.05. All of these model coefficients will be updated on the web-based BCSRc platform: www.breastcalc.org . CONCLUSIONS: The BCSRc continues to show excellent external-validation measures. Collectively, this prognostic tool can enhance the decision-making process, help stratify patients with an increased complication risk, and improve expectant management.

A multi-satellite framework to rapidly evaluate extreme biosphere cascades: The Western US 2021 drought and heatwave.

The increasing frequency and intensity of climate extremes and complex ecosystem responses motivate the need for integrated observational studies at low latency to determine biosphere responses and carbon-climate feedbacks. Here, we develop a satellite-based rapid attribution workflow and demonstrate its use at a 1-2-month latency to attribute drivers of the carbon cycle feedbacks during the 2020-2021 Western US drought and heatwave. In the first half of 2021, concurrent negative photosynthesis anomalies and large positive column CO2 anomalies were detected with satellites. Using a simple atmospheric mass balance approach, we estimate a surface carbon efflux anomaly of 132 TgC in June 2021, a magnitude corroborated independently with a dynamic global vegetation model. Integrated satellite observations of hydrologic processes, representing the soil-plant-atmosphere continuum (SPAC), show that these surface carbon flux anomalies are largely due to substantial reductions in photosynthesis because of a spatially widespread moisture-deficit propagation through the SPAC between 2020 and 2021. A causal model indicates deep soil moisture stores partially drove photosynthesis, maintaining its values in 2020 and driving its declines throughout 2021. The causal model also suggests legacy effects may have amplified photosynthesis deficits in 2021 beyond the direct effects of environmental forcing. The integrated, observation framework presented here provides a valuable first assessment of a biosphere extreme response and an independent testbed for improving drought propagation and mechanisms in models. The rapid identification of extreme carbon anomalies and hotspots can also aid mitigation and adaptation decisions.

A comprehensive profiling of quorum quenching by bacterial pigments identifies quorum sensing inhibition and antibiofilm action of prodigiosin against Acinetobacter baumannii.

Bacterial pigments represent a diverse group of secondary metabolites, which confer fitness advantages to the producers while residing in communities. The bioactive potential of such metabolites, including antimicrobial, anticancer, and immunomodulation, are being explored. Reckoning that a majority of such pigments are produced in response to quorum sensing (QS) mediated expression of biosynthetic gene clusters and, in turn, influence cell-cell communication, systemic profiling of the pigments for possible impact on QS appears crucial. A systemic screening of bacterial pigments for QS-inhibition combined with exploration of antibiofilm and antimicrobial action against Acinetobacter baumannii might offer viable alternatives to combat the priority pathogen. Major bacterial pigments are classified (clustered) based on their physicochemical properties, and representatives of the clusters are screened for QS inhibition. The screen highlighted prodigiosin as a potent quorum quencher, although its production from Serratia marcescens appeared to be QS-independent. In silico analysis indicated potential interactions between AbaI and AbaR, two major QS regulators in A. baumannii, and prodigiosin, which impaired biofilm formation, a major QS-dependent process in the bacteria. Prodigiosin augmented antibiotic action of ciprofloxacin against A. baumannii biofilms. Cell viability analysis revealed prodigiosin to be modestly cytotoxic against HEK293, a non-cancer human cell line. While developing dual-species biofilm, prodigiosin producer S. marcescens significantly impaired the fitness of A. baumannii. Enhanced susceptibility of A. baumannii toward colistin was also noted while growing in co-culture with S. marcescens. Antibiotic resistant isolates demonstrated varied responsiveness against prodigiosin, with two resistant strains demonstrating possible collateral sensitivity. Collectively, the results underpin the prospect of a prodigiosin-based therapeutic strategy in combating A. baumannii infection.