Cerebrovascular reactivity MRI as a biomarker for cerebral small vessel disease-related cognitive decline: Multi-site validation in the MarkVCID Consortium.

INTRODUCTION: Vascular contributions to cognitive impairment and dementia (VCID) represent a major factor in cognitive decline in older adults. The present study examined the relationship between cerebrovascular reactivity (CVR) measured by magnetic resonance imaging (MRI) and cognitive function in a multi-site study, using a predefined hypothesis. METHODS: We conducted the study in a total of three analysis sites and 263 subjects. Each site performed an identical CVR MRI procedure using 5% carbon dioxide inhalation. A global cognitive measure of Montreal Cognitive Assessment (MoCA) and an executive function measure of item response theory (IRT) score were used as outcomes. RESULTS: CVR and MoCA were positively associated, and this relationship was reproduced at all analysis sites. CVR was found to be positively associated with executive function. DISCUSSION: The predefined hypothesis on the association between CVR and a global cognitive score was validated in three independent analysis sites, providing support for CVR as a biomarker in VCID. HIGHLIGHTS: This study measured a novel functional index of small arteries referred to as cerebrovascular reactivity (CVR). CVR was positively associated with global cognition in older adults. This finding was observed in three independent cohorts at three sites. Our statistical analysis plan was predefined before beginning data collection.

Role of gender in short- and long-term outcomes after surgery for type A aortic dissection: analysis of a multicentre European registry.

OBJECTIVES: Gender difference in the outcome after type A aortic dissection (TAAD) surgery remains an issue of ongoing debate. In this study, we aimed to evaluate the impact of gender on the short- and long-term outcome after surgery for TAAD. METHODS: A multicentre European registry retrospectively included all consecutive TAAD surgery patients between 2005 and 2021 from 18 hospitals across 8 European countries. Early and late mortality, and cumulative incidence of aortic reoperation were compared between genders. RESULTS: A total of 3902 patients underwent TAAD surgery, with 1185 (30.4%) being females. After propensity score matching, 766 pairs of males and females were compared. No statistical differences were detected in the early postoperative outcome between genders. Ten-year survival was comparable between genders (47.8% vs 47.1%; log-rank test, P = 0.679), as well as cumulative incidences of distal or proximal aortic reoperations. Ten-year relative survival compared to country-, year-, age- and sex-matched general population was higher among males (0.65) compared to females (0.58). The time-period subanalysis revealed advancements in surgical techniques in both genders over the years. However, an increase in stroke was observed over time for both populations, particularly among females. CONCLUSIONS: The past 16 years have witnessed marked advancements in surgical techniques for TAAD in both males and females, achieving comparable early and late mortality rates. Despite these findings, late relative survival was still in favour of males.

Aortic arch surgery for DeBakey type 1 aortic dissection in patients aged 60 years or younger.

BACKGROUND: Extended aortic repair is considered a key issue for the long-term durability of surgery for DeBakey type 1 aortic dissection. The risk of aortic degeneration may be higher in young patients due to their long life expectancy. The early outcome and durability of aortic surgery in these patients were investigated in the present study. METHODS: The subjects of the present analysis were patients under 60 years old who underwent surgical repair for acute DeBakey type 1 aortic dissection at 18 cardiac surgery centres across Europe between 2005 and 2021. Patients underwent ascending aortic repair or total aortic arch repair using the conventional technique or the frozen elephant trunk technique. The primary outcome was 5-year cumulative incidence of reoperation on the distal aorta. RESULTS: Overall, 915 patients underwent surgical ascending aortic repair and 284 patients underwent surgical total aortic arch repair. The frozen elephant trunk procedure was performed in 128 patients. Among 245 propensity score-matched pairs, total aortic arch repair did not decrease the rate of distal aortic reoperation compared to ascending aortic repair (5-year cumulative incidence, 6.7% versus 6.7%, subdistributional hazard ratio 1.127, 95% c.i. 0.523 to 2.427). Total aortic arch repair increased the incidence of postoperative stroke/global brain ischaemia (25.7% versus 18.4%, P = 0.050) and dialysis (19.6% versus 12.7%, P = 0.003). Five-year mortality was comparable after ascending aortic repair and total aortic arch repair (22.8% versus 27.3%, P = 0.172). CONCLUSIONS: In patients under 60 years old with DeBakey type 1 aortic dissection, total aortic arch replacement compared with ascending aortic repair did not reduce the incidence of distal aortic operations at 5 years. When feasible, ascending aortic repair for DeBakey type 1 aortic dissection is associated with satisfactory early and mid-term outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04831073.

Ongoing introgression of a secondary sexual plumage trait in a stable avian hybrid zone.

Hybrid zones are dynamic systems where natural selection, sexual selection, and other evolutionary forces can act on reshuffled combinations of distinct genomes. The movement of hybrid zones, individual traits, or both are of particular interest for understanding the interplay between selective processes. In a hybrid zone involving two lek-breeding birds, secondary sexual plumage traits of Manacus vitellinus, including bright yellow collar and olive belly color, have introgressed asymmetrically ~50 km across the genomic center of the zone into populations more genetically similar to Manacus candei. Males with yellow collars are preferred by females and are more aggressive than parental M. candei, suggesting that sexual selection was responsible for the introgression of male traits. We assessed the spatial and temporal dynamics of this hybrid zone using historical (1989 - 1994) and contemporary (2017 - 2020) transect samples to survey both morphological and genetic variation. Genome-wide SNP data and several male phenotypic traits show that the genomic center of the zone has remained spatially stable, whereas the olive belly color of male M. vitellinus has continued to introgress over this time period. Our data suggest that sexual selection can continue to shape phenotypes dynamically, independent of a stable genomic transition between species.

The three-dimensional structure of DapE from Enterococcus faecium reveals new insights into DapE/ArgE subfamily ligand specificity.

DapE is a Zn2+-metallohydrolase recognized as a drug target for bacterial control. It is a homodimer that requires the exchange of interface strands by an induced fit essential for catalysis. Identifying novel anti-DapE agents requires greater structural details. Most of the characterized DapEs are from the Gram-negative group. Here, two high-resolution DapE crystal structures from Enterococcus faecium are presented for the first time with novel aspects. A loosened enzyme intermediate between the open and closed conformations is observed. Substrates may bind to loose state, subsequently it closes, where hydrolysis occurs, and finally, the change to the open state leads to the release of the products. Mutation of His352 suggests a role, along with His194, in the oxyanion stabilization in the mono-metalated Zn2+ isoform, while in the di-metalated isoform, the metal center 2 complements it function. An aromatic-π box potentially involved in the interaction of DapE with other proteins, and a peptide flip could determine the specificity in the Gram-positive ArgE/DapE group. Finally, details of two extra-catalytic cavities whose geometry changes depending on the conformational state of the enzyme are presented. These cavities could be a target for developing non-competitive agents that trap the enzyme in an inactive state.

Bilateral Inferior Rectus Schwannoma and Strabismus: A Case Report.

Schwannomas, also known as neurilemomas, are peripheral nerve sheath neoplasms. They can be sporadic or associated with genetic syndromes including neurofibromatosis type 2 (NF2). Schwannomas may lead to symptoms by exerting pressure on nearby structures, such as nerve and muscle fibers. In this study, we present the case of a 22-year-old female with a history of NF2 who, upon examination, presented with a visibly enlarged salmon-colored mass involving the left inferior rectus that she had since the age of 12 years. Ocular examinations revealed a small left hypertropia and exotropia in all gazes. Magnetic resonance imaging confirmed bilateral involvement of the inferior rectus muscles. She had a partial excisional biopsy of the mass involving the left inferior rectus muscle that confirmed the presence of schwannoma. This case highlights the importance of comprehensive evaluation of sensory and motor functions as well as considering orbital schwannomas in cases of strabismus, especially within the context of neurofibromatosis.

Anorectal Infections in Neutropenic Leukemia Patients: A Common Clinical Challenge.

Anorectal infections in neutropenic leukemia patients are a significant and potentially life-threatening complication. The pathogenesis of this condition is not entirely understood and believed to be multifactorial, including mucosal injury as a result of cytotoxic drugs, profound neutropenia and impaired host defense. Establishing an early diagnosis is key and often made clinically on the basis of signs and symptoms, but also from imaging studies demonstrating perianal inflammation or fluid collection. The management of anorectal infections in neutropenic leukemia patients is not straightforward, as there are no well-conducted studies on this entity. This review seeks to provide a framework into the pathophysiology and clinical presentation of anorectal infections in neutropenic leukemia patients, propose a diagnostic approach and to discuss controversies in the management of this condition.

Infection-associated gene regulation of L-tartrate metabolism in Salmonella enterica serovar Typhimurium.

Enteric pathogens such as Salmonella enterica serovar Typhimurium experience spatial and temporal changes to the metabolic landscape throughout infection. Host reactive oxygen and nitrogen species non-enzymatically convert monosaccharides to alpha hydroxy acids, including L-tartrate. Salmonella utilizes L-tartrate early during infection to support fumarate respiration, while L-tartrate utilization ceases at later time points due to the increased availability of exogenous electron acceptors such as tetrathionate, nitrate, and oxygen. It remains unknown how Salmonella regulates its gene expression to metabolically adapt to changing nutritional environments. Here, we investigated how the transcriptional regulation for L-tartrate metabolism in Salmonella is influenced by infection-relevant cues. L-tartrate induces the transcription of ttdBAU, genes involved in L-tartrate utilization. L-tartrate metabolism is negatively regulated by two previously uncharacterized transcriptional regulators TtdV (STM3357) and TtdW (STM3358), and both TtdV and TtdW are required for the sensing of L-tartrate. The electron acceptors nitrate, tetrathionate, and oxygen repress ttdBAU transcription via the two-component system ArcAB. Furthermore, the regulation of L-tartrate metabolism is required for optimal fitness in a mouse model of Salmonella-induced colitis. TtdV, TtdW, and ArcAB allow for the integration of two cues, i.e., substrate availability and availability of exogenous electron acceptors, to control L-tartrate metabolism. Our findings provide novel insights into how Salmonella prioritizes the utilization of different electron acceptors for respiration as it experiences transitional nutrient availability throughout infection. IMPORTANCE: Bacterial pathogens must adapt their gene expression profiles to cope with diverse environments encountered during infection. This coordinated process is carried out by the integration of cues that the pathogen senses to fine-tune gene expression in a spatiotemporal manner. Many studies have elucidated the regulatory mechanisms of how Salmonella sense metabolites in the gut to activate or repress its virulence program; however, our understanding of how Salmonella coordinates its gene expression to maximize the utilization of carbon and energy sources found in transitional nutrient niches is not well understood. In this study, we discovered how Salmonella integrates two infection-relevant cues, substrate availability and exogenous electron acceptors, to control L-tartrate metabolism. From our experiments, we propose a model for how L-tartrate metabolism is regulated in response to different metabolic cues in addition to characterizing two previously unknown transcriptional regulators. This study expands our understanding of how microbes combine metabolic cues to enhance fitness during infection.

Femoral arterial cannulation for surgical repair of stanford type A aortic dissection.

BACKGROUND: The benefits and harms associated with femoral artery cannulation over other sites of arterial cannulation for surgical repair of acute Stanford type A aortic dissection (TAAD) are not conclusively established. METHODS: We evaluated the outcomes after surgery for TAAD using femoral artery cannulation, supra-aortic arterial cannulation (i.e., innominate/subclavian/axillary artery cannulation), and direct aortic cannulation. RESULTS: 3751 (96.1%) patients were eligible for this analysis. In-hospital mortality using supra-aortic arterial cannulation was comparable to femoral artery cannulation (17.8% vs. 18.4%; adjusted OR 0.846, 95% CI 0.799-1.202). This finding was confirmed in 1028 propensity score-matched pairs of patients with supra-aortic arterial cannulation or femoral artery cannulation (17.5% vs. 17.0%, p = 0.770). In-hospital mortality after direct aortic cannulation was lower compared to femoral artery cannulation (14.0% vs. 18.4%, adjusted OR 0.703, 95% CI 0.529-0.934). Among 583 propensity score-matched pairs of patients, direct aortic cannulation was associated with lower rates of in-hospital mortality (13.4% vs. 19.6%, p = 0.004) compared to femoral artery cannulation. Switching of the primary site of arterial cannulation was associated with increased rate of in-hospital mortality (36.5% vs. 17.0%; adjusted OR 2.730, 95% CI 1.564-4.765). Ten-year mortality was similar in the study cohorts. CONCLUSIONS: In this study, the outcomes of surgery for TAAD using femoral arterial cannulation were comparable to those using supra-aortic arterial cannulation. However, femoral arterial cannulation was associated with higher in-hospital mortality than direct aortic cannulation. TRIAL REGISTRATION: ClinicalTrials.gov registration code: NCT04831073.

Nature of Neurological Complications and Outcome After Surgery for Type A Aortic Dissection.

Surgery for type A aortic dissection (TAAD) is frequently complicated by neurologic complications. The prognostic impact of neurologic complications of different nature has been investigated in this study. The subjects of this analysis were 3,902 patients who underwent surgery for acute TAAD from the multicenter European Registry of Type A Aortic Dissection (ERTAAD). During the index hospitalization, 722 patients (18.5%) experienced stroke/global brain ischemia. Ischemic stroke was detected in 539 patients (13.8%), hemorrhagic stroke in 76 patients (1.9%) and global brain ischemia in 177 patients (4.5%), with a few patients having had findings of more than 1 of these conditions. In-hospital mortality was increased significantly in patients with postoperative ischemic stroke (25.6%, adjusted odds ratio [OR] 2.422, 95% confidence interval [CI] 1.825 to 3.216), hemorrhagic stroke (48.7%, adjusted OR 4.641, 95% CI 2.524 to 8.533), and global brain ischemia (74.0%, adjusted OR 22.275, 95% CI 14.537 to 35.524) compared with patients without neurologic complications (13.5%). Similarly, patients who experienced ischemic stroke (46.3%, adjusted hazard ratio [HR] 1.719, 95% CI 1.434 to 2.059), hemorrhagic stroke (62.8%, adjusted HR 3.236, 95% CI 2.314 to 4.525), and global brain ischemia (83.9%, adjusted HR 12.777, 95% CI 10.325 to 15.810) had significantly higher 5-year mortality than patients without postoperative neurologic complications (27.5%). The negative prognostic effect of neurologic complications on survival vanished about 1 year after surgery. In conclusion, postoperative ischemic stroke, hemorrhagic stroke, and global cerebral ischemia increased early and midterm mortality after surgery for acute TAAD. The magnitude of risk of mortality increased with the severity of the neurologic complications, with postoperative hemorrhagic stroke and global brain ischemia being highly lethal complications.

Glucuronic acid confers colonization advantage to enteric pathogens.

Glucuronidation is a detoxification process to eliminate endo- and xeno-biotics and neurotransmitters from the host circulation. Glucuronosyltransferase binds these compounds to glucuronic acid (GlcA), deactivating them and allowing their elimination through the gastrointestinal (GI) tract. However, the microbiota produces ß-glucuronidases that release GlcA and reactivate these compounds. Enteric pathogens such as enterohemorrhagic Escherichia coli (EHEC) and Citrobacter rodentium sense and utilize galacturonic acid (GalA), an isomer of GlcA, to outcompete the microbiota promoting gut colonization. However, the role of GlcA in pathogen colonization has not been explored. Here, we show that treatment of mice with a microbial ß-glucuronidase inhibitor (GUSi) decreased C. rodentium's colonization of the GI tract, without modulating bacterial virulence or host inflammation. Metagenomic studies indicated that GUSi did not change the composition of the intestinal microbiota in these animals. GlcA confers an advantage for pathogen expansion through its utilization as a carbon source. Congruently mutants unable to catabolize GlcA depict lower GI colonization compared to wild type and are not sensitive to GUSi. Germfree mice colonized with a commensal E. coli deficient for ß-glucuronidase production led to a decrease of C. rodentium tissue colonization, compared to animals monocolonized with an E. coli proficient for production of this enzyme. GlcA is not sensed as a signal and doesn't activate virulence expression but is used as a metabolite. Because pathogens can use GlcA to promote their colonization, inhibitors of microbial ß-glucuronidases could be a unique therapeutic against enteric infections without disturbing the host or microbiota physiology.

Evaluation of targeting αVß3 in breast cancers using RGD peptide-based agents.

Patients with HER2-positive and triple negative breast cancer (TNBC) are associated with increased risk to develop metastatic disease including reoccurring disease that is resistant to standard and targeted therapies. The αVß3 has been implicated in BC including metastatic disease. The aims of this study were to investigate the potential of αVß3-targeted peptides to deliver radioactive payloads to BC tumors expressing αVß3 on the tumor cells or limited to the tumors' neovascular. Additionally, we aimed to assess the pharmacokinetic profile of the targeted α-particle therapy (TAT) agent [225Ac]Ac-DOTA-cRGDfK dimer peptide and the in vivo generated decay daughters. The expression of αVß3 in a HER2-positive and a TNBC cell line were evaluated using western blot analysis. The pharmacokinetics of [111In]In-DOTA-cRGDfK dimer, a surrogate for the TAT-agent, was evaluated in subcutaneous mouse tumor models. The pharmacokinetic of the TAT-agent [225Ac]Ac-DOTA-cRGDfK dimer and its decay daughters were evaluated in healthy mice. Selective uptake of [111In]In-DOTA-cRGDfK dimer was shown in subcutaneous tumor models using αVß3-positive tumor cells as well as αVß3-negative tumor cells where the expression is limited to the neovasculature. Pharmacokinetic studies demonstrated rapid accumulation in the tumors with clearance from non-target organs. Dosimetric analysis of [225Ac]Ac-DOTA-cRGDfK dimer showed the highest radiation absorbed dose to the kidneys, which included the contributions from the free in vivo generated decay daughters. This study shows the potential of delivering radioactive payloads to BC tumors that have αVß3 expression on the tumor cells as well as limited expression to the neovascular of the tumor. Furthermore, this work determines the radiation absorbed doses to normal organs/tissues and identified key organs that act as suppliers and receivers of the actinium-225 free in vivo generated α-particle-emitting decay daughters.

Prognostic Value of Lymph Node Ratio in Patients with Uterine Carcinosarcoma.

Uterine carcinosarcoma is a rare high-grade endometrial cancer. Controversy has surrounded a number of aspects in the diagnosis and management of this unique clinicopathological entity, including the efficacy of adjuvant therapy, which has been questioned. An unusual surgico-pathological parameter with prognostic significance in a number of tumour sites is the lymph node ratio (LNR). The availability of data in this respect has been scarce in the literature. The primary aim of this collaborative study was to evaluate the prognostic value of LNR in patients with uterine carcinosarcoma. LNR is a recognized lymph node metric used to stratify prognosis in a variety of malignancies. In this European multinational retrospective study, 93 women with uterine carcinosarcoma were included in the final analysis. We used t-tests and ANOVA for comparison between quantitative variables between the groups, and chi-square tests for qualitative variables. A multivariate analysis using Cox regression analysis was performed to determine potential prognostic factors, including the LNR. Patients were grouped with respect to LNR in terms of 0%, 20% > 0% and >20%. The analysis revealed LNR to be a significant predictor of progression-free survival (HR 1.69, CI (1.12-2.55), p = 0.012) and overall survival (HR 1.71, CI (1.07-2.7), p = 0.024). However, LNR did not remain a significant prognostic factor on multivariate analysis. Due to limitations of the retrospective study, a prospective large multinational study, which takes into effect the most recent changes to clinical practice, is warranted to elucidate the value of the pathophysiological metrics of the lymphatic system associated with prognosis.

C1–C2 intraarticular distraction with anterior cervical cages for basilar invagination realignment: Operative technique nuances and review of literature

Neurosurgical management of basilar invagination (BI) has traditionally been aimed at direct cervicomedullary decompression through transoral dens resection or suboccipital decompression with supplemental instrumented fixation. Dr. Goel introduced chronic atlantoaxial dislocation (AAD) as the etiology in most cases of BI and described a technique for distracting the C1–C2 joint with interfacet spacers to achieve reduction and anatomic realignment. We present our modification to Goel’s surgical technique, in which we utilize anterior cervical discectomy (ACD) cages as C1–C2 interfacet implants. A young adult male presented to our institution with BI, cervicomedullary compression, occipitalization of C1, and Chiari 1 malformation. There was AAD of C1 over the C2 lateral masses. This reduced some with preoperative traction. He underwent successful C1–C2 interfacet joint reduction and arthrodesis with anterior cervical discectomy (ACD) cages and concomittant occiput to C2 instrumented fusion. BI can be effectively treated through reduction of AAD and by utilizing ACD cages as interfacet spacers. (AU)

El tratamiento neuroquirúrgico tradicional para la impresión basilar es principalmente a través de un abordaje trans-oral para la resección del proceso odontoide, seguido de una descompresión suboccipital con instrumentación posterior cervical. Dr. Goel presenta la dislocación atlanto-axial (AA) como una de las etiologías principales en los casos de impresión basilar. A su vez, describió la técnica quirúrgica que incluye la distracción de la articulación AA con cajas para fusión permitiendo la reducción y reajuste anatómico cervical. En este artículo presentamos una variación a la técnica quirúrgica del Dr. Goel en el cual utilizamos implantes utilizados en la discectomía y fusión cervical anterior (DFCA) para la articulación facetaria de C1–C2. Presentamos un paciente adulto masculino que evaluamos en nuestra institución con impresión basilar, compresión cérvico-medular, fusión occipital con el atlas y malformación de Chiari tipo 1. En adición, el paciente tenía evidencia radiográfica de dislocación AA. Se logro obtener reducción mínima de la impresión basilar con tracción cervical pre-operatoria. Luego, se sometió al tratamiento quirúrgico que consistió en el uso de implantes cervicales para la reducción y fusión de la articulación facetaria de C1–C2 complementado por instrumentación y fusión craneocervical. Esta técnica presentada sugiere que la reducción y reajuste anatómico cervical de la dislocación AA con implantes utilizados para DFCA puede ser efectivo para el tratamiento de impresión basilar. (AU)

Classification of the Urgency of the Procedure and Outcome of Acute Type A Aortic Dissection.

Surgery for type A aortic dissection (TAAD) is associated with a high risk of early mortality. The prognostic impact of a new classification of the urgency of the procedure was evaluated in this multicenter cohort study. Data on consecutive patients who underwent surgery for acute TAAD were retrospectively collected in the multicenter, retrospective European Registry of TAAD (ERTAAD). The rates of in-hospital mortality of 3,902 consecutive patients increased along with the ERTAAD procedure urgency grades: urgent procedure 10.0%, emergency procedure grade 1 13.3%, emergency procedure grade 2 22.1%, salvage procedure grade 1 45.6%, and salvage procedure grade 2 57.1% (p <0.0001). Preoperative arterial lactate correlated with the urgency grades. Inclusion of the ERTAAD procedure urgency classification significantly improved the area under the receiver operating characteristics curves of the regression model and the integrated discrimination indexes and the net reclassification indexes. The risk of postoperative stroke/global brain ischemia, mesenteric ischemia, lower limb ischemia, dialysis, and acute heart failure increased along with the urgency grades. In conclusion, the urgency of surgical repair of acute TAAD, which seems to have a significant impact on the risk of in-hospital mortality, may be useful to improve the stratification of the operative risk of these critically ill patients. This study showed that salvage surgery for TAAD is justified because half of the patients may survive to discharge.

Gene regulation of infection-associated L-tartrate metabolism in Salmonella enterica serovar Typhimurium.

Enteric pathogens such as Salmonella enterica serovar Typhimurium experience spatial and temporal changes to the metabolic landscape throughout infection. Host reactive oxygen and nitrogen species non-enzymatically convert monosaccharides to alpha hydroxy acids, including L-tartrate. Salmonella utilizes L-tartrate early during infection to support fumarate respiration, while L-tartrate utilization ceases at later time points due to the increased availability of exogenous electron acceptors such as tetrathionate, nitrate, and oxygen. It remains unknown how Salmonella regulates its gene expression to metabolically adapt to changing nutritional environments. Here, we investigated how the transcriptional regulation for L-tartrate metabolism in Salmonella is influenced by infection-relevant cues. L-tartrate induces the transcription of ttdBAU, genes involved in L-tartrate utilization. L-tartrate metabolism is negatively regulated by two previously uncharacterized transcriptional regulators TtdV (STM3357) and TtdW (STM3358), and both TtdV and TtdW are required for sensing of L-tartrate. The electron acceptors nitrate, tetrathionate, and oxygen repress ttdBAU transcription via the two-component system ArcAB. Furthermore, regulation of L-tartrate metabolism is required for optimal fitness in a mouse model of Salmonella-induced colitis. TtdV, TtdW, and ArcAB allow for the integration of two cues, substrate availability and availability of exogenous electron acceptors, to control L-tartrate metabolism. Our findings provide novel insights into how Salmonella prioritizes utilization of different electron acceptors for respiration as it experiences transitional nutrient availability throughout infection.

Structural and functional properties of uridine 5'-monophosphate synthase from Coffea arabica.

In higher eukaryotes and plants, the last two sequential steps in the de novo biosynthesis of uridine 5'-monophosphate (UMP) are catalyzed by a bifunctional natural chimeric protein called UMP synthase (UMPS). In higher plants, UMPS consists of two naturally fused enzymes: orotate phosphoribosyltransferase (OPRTase) at N-terminal and orotidine-5'-monophosphate decarboxylase (ODCase) at C-terminal. In this work, we obtained the full functional recombinant protein UMPS from Coffea arabica (CaUMPS) and studied its structure-function relationships. A biochemical and structural characterization of a plant UMPS with its two functional domains is described together with the presentation of the first crystal structure of a plant ODCase at 1.4 Å resolution. The kinetic parameters measured of CaOPRTase and CaODCase domains were comparable to those reported. The crystallographic structure revealed that CaODCase is a dimer that conserves the typical fold observed in other ODCases from prokaryote and eukaryote with a 1-deoxy-ribofuranose-5'-phosphate molecule bound in the active site of one subunit induced a closed conformation. Our results add to the knowledge of one of the key enzymes of the de novo biosynthesis of pyrimidines in plant metabolism and open the door to future applications.

C1-C2 intraarticular distraction with anterior cervical cages for basilar invagination realignment: Operative technique nuances and review of literature.

Neurosurgical management of basilar invagination (BI) has traditionally been aimed at direct cervicomedullary decompression through transoral dens resection or suboccipital decompression with supplemental instrumented fixation. Dr. Goel introduced chronic atlantoaxial dislocation (AAD) as the etiology in most cases of BI and described a technique for distracting the C1-C2 joint with interfacet spacers to achieve reduction and anatomic realignment. We present our modification to Goel's surgical technique, in which we utilize anterior cervical discectomy (ACD) cages as C1-C2 interfacet implants. A young adult male presented to our institution with BI, cervicomedullary compression, occipitalization of C1, and Chiari 1 malformation. There was AAD of C1 over the C2 lateral masses. This reduced some with preoperative traction. He underwent successful C1-C2 interfacet joint reduction and arthrodesis with anterior cervical discectomy (ACD) cages and concomittant occiput to C2 instrumented fusion. BI can be effectively treated through reduction of AAD and by utilizing ACD cages as interfacet spacers.

Genomics and conservation: Guidance from training to analyses and applications.

Environmental change is intensifying the biodiversity crisis and threatening species across the tree of life. Conservation genomics can help inform conservation actions and slow biodiversity loss. However, more training, appropriate use of novel genomic methods and communication with managers are needed. Here, we review practical guidance to improve applied conservation genomics. We share insights aimed at ensuring effectiveness of conservation actions around three themes: (1) improving pedagogy and training in conservation genomics including for online global audiences, (2) conducting rigorous population genomic analyses properly considering theory, marker types and data interpretation and (3) facilitating communication and collaboration between managers and researchers. We aim to update students and professionals and expand their conservation toolkit with genomic principles and recent approaches for conserving and managing biodiversity. The biodiversity crisis is a global problem and, as such, requires international involvement, training, collaboration and frequent reviews of the literature and workshops as we do here.

Genomic analysis supports Cape Lion population connectivity prior to colonial eradication and extinction.

Cape lions (Panthera leo melanochaitus) formerly ranged throughout the grassland plains of the "Cape Flats" in what is today known as the Western Cape Province, South Africa. Cape lions were likely eradicated because of overhunting and habitat loss after European colonization. European naturalists originally described Cape lions as "black-maned lions" and claimed that they were phenotypically distinct. However, other depictions and historical descriptions of lions from the Cape report mixed or light coloration and without black or extensively developed manes. These findings suggest that, rather than forming a distinct population, Cape lions may have had phenotypic and genotypic variation similar to other African lions. Here we investigate Cape lion genome characteristics, population dynamics, and genetic distinctiveness prior to their extinction. We generated genomic data from 2 historic Cape lions to compare to 118 existing high-coverage mitogenomes, and low-coverage nuclear genomes of 53 lions from 13 African countries. We show that, before their eradication, lions from the Cape Flats had diverse mitogenomes and nuclear genomes that clustered with lions from both southern and eastern Africa. Cape lions had high genome-wide heterozygosity and low inbreeding coefficients, indicating that populations in the Cape Flats went extinct so rapidly that genomic effects associated with long-term small population size and isolation were not detectable. Our findings do not support the characterization of Cape lions as phylogeographically distinct, as originally put forth by some European naturalists, and illustrates how alternative knowledge systems, for example, Indigenous perspectives, could potentially further inform interpretations of species histories.