Transcription factor WOX11 modulates tolerance to cyst nematodes via adventitious lateral root formation.

The transcription factor WUSCHEL-RELATED HOMEOBOX 11 (WOX11) in Arabidopsis (Arabidopsis thaliana) initiates the formation of adventitious lateral roots upon mechanical injury in primary roots. Root-invading nematodes also induce de novo root organogenesis leading to excessive root branching, but it is not known if this symptom of disease involves mediation by WOX11 and if it benefits the plant. Here, we show with targeted transcriptional repression and reporter gene analyses in Arabidopsis that the beet cyst nematode Heterodera schachtii activates WOX11-mediated adventitious lateral rooting from primary roots close to infection sites. The activation of WOX11 in nematode-infected roots occurs downstream of jasmonic acid-dependent damage signaling via ETHYLENE RESPONSE FACTOR109, linking adventitious lateral root formation to nematode damage to host tissues. By measuring different root system components, we found that WOX11-mediated formation of adventitious lateral roots compensates for nematode-induced inhibition of primary root growth. Our observations further demonstrate that WOX11-mediated rooting reduces the impact of nematode infections on aboveground plant development and growth. Altogether, we conclude that the transcriptional regulation by WOX11 modulates root system plasticity under biotic stress, which is one of the key mechanisms underlying the tolerance of Arabidopsis to cyst nematode infections.

Use of Carotid Web Angioarchitecture for Stroke Risk Assessment.

OBJECTIVE: To examine the usefulness of carotid web (CW), carotid bifurcation and their combined angioarchitectural measurements in assessing stroke risk. METHODS: Anatomic data on the internal carotid artery (ICA), common carotid artery (CCA), and the CW were gathered as part of a retrospective study from symptomatic (stroke) and asymptomatic (nonstroke) patients with CW. We built a model of stroke risk using principal-component analysis, Firth regression trained with 5-fold cross-validation, and heuristic binary cutoffs based on the Minimal Description Length principle. RESULTS: The study included 22 patients, with a mean age of 55.9 ± 12.8 years; 72.9% were female. Eleven patients experienced an ischemic stroke. The first 2 principal components distinguished between patients with stroke and patients without stroke. The model showed that ICA-pouch tip angle (P = 0.036), CCA-pouch tip angle (P = 0.036), ICA web-pouch angle (P = 0.036), and CCA web-pouch angle (P = 0.036) are the most important features associated with stroke risk. Conversely, CCA and ICA anatomy (diameter and angle) were not found to be risk factors. CONCLUSIONS: This pilot study shows that using data from computed tomography angiography, carotid bifurcation, and CW angioarchitecture may be used to assess stroke risk, allowing physicians to tailor care for each patient according to risk stratification.

Post-translational modifications of ATG8 proteins - an emerging mechanism of autophagy control.

Autophagy is a recycling mechanism involved in cellular homeostasis with key implications for health and disease. The conjugation of the ATG8 family proteins, which includes LC3B (also known as MAP1LC3B), to autophagosome membranes, constitutes a hallmark of the canonical autophagy process. After ATG8 proteins are conjugated to the autophagosome membranes via lipidation, they orchestrate a plethora of protein-protein interactions that support key steps of the autophagy process. These include binding to cargo receptors to allow cargo recruitment, association with proteins implicated in autophagosome transport and autophagosome-lysosome fusion. How these diverse and critical protein-protein interactions are regulated is still not well understood. Recent reports have highlighted crucial roles for post-translational modifications of ATG8 proteins in the regulation of ATG8 functions and the autophagy process. This Review summarizes the main post-translational regulatory events discovered to date to influence the autophagy process, mostly described in mammalian cells, including ubiquitylation, acetylation, lipidation and phosphorylation, as well as their known contributions to the autophagy process, physiology and disease.

From root to shoot: quantifying nematode tolerance in Arabidopsis thaliana by high-throughput phenotyping of plant development.

Nematode migration, feeding site formation, withdrawal of plant assimilates, and activation of plant defence responses have a significant impact on plant growth and development. Plants display intraspecific variation in tolerance limits for root-feeding nematodes. Although disease tolerance has been recognized as a distinct trait in biotic interactions of mainly crops, we lack mechanistic insights. Progress is hampered by difficulties in quantification and laborious screening methods. We turned to the model plant Arabidopsis thaliana, since it offers extensive resources to study the molecular and cellular mechanisms underlying nematode-plant interactions. Through imaging of tolerance-related parameters, the green canopy area was identified as an accessible and robust measure for assessing damage due to cyst nematode infection. Subsequently, a high-throughput phenotyping platform simultaneously measuring the green canopy area growth of 960 A. thaliana plants was developed. This platform can accurately measure cyst nematode and root-knot nematode tolerance limits in A. thaliana through classical modelling approaches. Furthermore, real-time monitoring provided data for a novel view of tolerance, identifying a compensatory growth response. These findings show that our phenotyping platform will enable a new mechanistic understanding of tolerance to below-ground biotic stress.

Comparative genomics among cyst nematodes reveals distinct evolutionary histories among effector families and an irregular distribution of effector-associated promoter motifs.

Potato cyst nematodes (PCNs), an umbrella term used for two species, Globodera pallida and G. rostochiensis, belong worldwide to the most harmful pathogens of potato. Pathotype-specific host plant resistances are essential for PCN control. However, the poor delineation of G. pallida pathotypes has hampered the efficient use of available host plant resistances. Long-read sequencing technology allowed us to generate a new reference genome of G. pallida population D383 and, as compared to the current reference, the new genome assembly is 42 times less fragmented. For comparison of diversification patterns of six effector families between G. pallida and G. rostochiensis, an additional reference genome was generated for an outgroup, the beet cyst nematode Heterodera schachtii (IRS population). Large evolutionary contrasts in effector family topologies were observed. While VAPs (venom allergen-like proteins) diversified before the split between the three cyst nematode species, the families GLAND5 and GLAND13 only expanded in PCNs after their separation from the genus Heterodera. Although DNA motifs in the promoter regions thought to be involved in the orchestration of effector expression ("DOG boxes") were present in all three cyst nematode species, their presence is not a necessity for dorsal gland-produced effectors. Notably, DOG box dosage was only loosely correlated with the expression level of individual effector variants. Comparison of the G. pallida genome with those of two other cyst nematodes underlined the fundamental differences in evolutionary history between effector families. Resequencing of PCN populations with different virulence characteristics will allow for the linking of these characteristics to the composition of the effector repertoire as well as for the mapping of PCN diversification patterns resulting from extreme anthropogenic range expansion.

Neuroprotective association of preoperative renin-angiotensin system blocking agents use in patients undergoing carotid interventions.

OBJECTIVE: The optimal medical management strategy in the periprocedural period for patients undergoing carotid artery interventions is not well described. Renin-angiotensin-system blocking (RASB) agents are considered to be among the first line anti-hypertensive agents; however, their role in the perioperative period is unclear. The objective of this study was to examine the relationship between the use of RASB agents on periprocedural outcomes in patients undergoing carotid interventions-carotid endarterectomy (CEA), transfemoral carotid artery stenting (CAS), and transcervical carotid artery revascularization (TCAR). METHOD: The Society for Vascular Surgery Quality Initiative database was queried for all patients undergoing CAS, CEA, and TCAR between 2003 and 2020. Patients were stratified into two groups based upon their use of RASB agents in the periprocedural period. The primary endpoint was periprocedural neurologic events (including both strokes and transient ischemic attacks (TIAs)). The secondary endpoints were peri-procedural mortality and significant cardiac events, including myocardial infarction, dysrhythmia, and congestive heart failure. RESULTS: Over 150,000 patients were included in the analysis: 13,666 patients underwent TCAR, 13,811 underwent CAS, and 125,429 underwent CEA for carotid artery stenosis. Overall, 52.2% of patients were maintained on RASB agents. Among patients undergoing CEA, patients on RASB agents had a significantly lower rate of periprocedural neurologic events (1.7% versus 2.0%, p =0.001). The peri-procedural neurological event rate in the TCAR cohort was similarly reduced in those treated with RASB agents, but did not reach statistical significance (2.0% vs 2.4%, p = 0.162). Among patients undergoing CAS, there was no difference in perioperative neurologic events between the RASB treated and untreated cohorts (3.4% vs 3.2%, p = 0.234); however, the use of RASB agents was significantly associated with lower mortality (1.2% vs 1.7%, p =0.001) with CAS. The use of preoperative RAS-blocking agents did not appear to affect the overall rates of adverse cardiac events with any of the three carotid intervention types, or periprocedural mortality following CEA or TCAR. On multivariable analysis, the use of RAS-blocking agents was independently associated with lower rates of post-procedural neurologic events in patients undergoing CEA (OR 0.819, CI 0.747-0.898; p = 0.01) and TCAR (OR 0.869, CI 0.768-0.984; p = 0.026), but not in those undergoing CAS (OR 0.967, CI 0.884-1.057; p = 0.461). CONCLUSION: The use of peri-procedural RASB agents was associated with a significantly decreased rate of neurologic events in patients undergoing both CEA and TCAR. This effect was not observed in patients undergoing CAS. As carotid interventions warrant absolute minimization of perioperative complications in order to provide maximum efficacy with regard to stroke protection, the potential neuro-protective effect associated with RASB agents use following CEA and TCAR warrants further examination.

Root architecture plasticity in response to endoparasitic cyst nematodes is mediated by damage signaling.

Plant root architecture plasticity in response to biotic stresses has not been thoroughly investigated. Infection by endoparasitic cyst nematodes induces root architectural changes that involve the formation of secondary roots at infection sites. However, the molecular mechanisms regulating secondary root formation in response to cyst nematode infection remain largely unknown. We first assessed whether secondary roots form in a nematode density-dependent manner by challenging wild-type Arabidopsis plants with increasing numbers of cyst nematodes (Heterodera schachtii). Next, using jasmonate-related reporter lines and knockout mutants, we tested whether tissue damage by nematodes triggers jasmonate-dependent secondary root formation. Finally, we verified whether damage-induced secondary root formation depends on local auxin biosynthesis at nematode infection sites. Intracellular host invasion by H. schachtii triggers a transient local increase in jasmonates, which activates the expression of ERF109 in a COI1-dependent manner. Knockout mutations in COI1 and ERF109 disrupt the nematode density-dependent increase in secondary roots observed in wild-type plants. Furthermore, ERF109 regulates secondary root formation upon H. schachtii infection via local auxin biosynthesis. Host invasion by H. schachtii triggers secondary root formation via the damage-induced jasmonate-dependent ERF109 pathway. This points at a novel mechanism underlying plant root plasticity in response to biotic stress.

Use of Smartphones to Increase Safe Sexual Behavior in Youths at Risk for HIV.

In Mexico, young people continue to experience problems due to a lack of correct and consistent condom use during sexual intercourse. OBJECTIVE: to evaluate the effect of a randomized controlled clinical trial with the use of smartphones to increase safe sex intentions and safe sexual behavior. METHODS: experimental design with two treatment groups with 177 young people who requested the rapid HIV test in a non-governmental organization in the city of Monterrey, Mexico. The experimental group was given Respect M-Health with the use of mobile devices; the control group was given similar counseling without the use of mobile technology and 8 pencil and paper instruments were used. RESULTS: the effect of the experimental group was greater in safe sexual behavior reflected in the means at pre-test M=64.80 (SD=1.86), post-test M=85.33 (SD=1.54), and at 30 days M=87.40 (SD=1.52), and in the safe sex intentions factor at pre-test M=78.50 (SD=3.07), post-test M=94.70 (SD=2.46), and at 30 days M=95.74 (SD=2.29). CONCLUSIONS: Smartphone use was an effective tool as a support to increase safe sexual behavior in youth.

En México, los jóvenes siguen presentando problemas debido a la falta de uso correcto y consistente del preservativo durante las relaciones sexuales. OBJETIVO: evaluar el efecto de un ensayo clínico controlado y aleatorizado con el uso de teléfonos inteligentes para aumentar las intenciones de sexo seguro y la conducta sexual segura. Métodos: diseño experimental con dos grupos de tratamiento con 177 jóvenes que solicitaron la prueba rápida de VIH en una Organización no Gubernamental en la ciudad de Monterrey, México. Al grupo experimental se le brindó Respeto M-Salud para el uso de dispositivos móviles; al grupo control se le entregó una herramienta similar, pero sin el uso de tecnología móvil, y se utilizaron 8 instrumentos de lápiz y papel. RESULTADOS: el efecto del grupo experimental fue mayor en la conducta sexual segura reflejado en las medias del pre-test M=64.80 (SD=1.86), post-test M=85.33 (SD=1.54) y a los 30 días M=87.40 (SD=1.52); y en el factor de intenciones de sexo seguro, se reflejó de esta manera en el pre-test M=78.50 (SD=3.07), post-test M=94.70 (SD=2.46) y a los 30 días M=95.74 (SD=2.29). CONCLUSIONES: El uso de teléfonos inteligentes fue una herramienta eficaz como apoyo para aumentar la conducta sexual segura en los jóvenes.

The genome and lifestage-specific transcriptomes of a plant-parasitic nematode and its host reveal susceptibility genes involved in trans-kingdom synthesis of vitamin B5.

Plant-parasitic nematodes are a major threat to crop production in all agricultural systems. The scarcity of classical resistance genes highlights a pressing need to find new ways to develop nematode-resistant germplasm. Here, we sequence and assemble a high-quality phased genome of the model cyst nematode Heterodera schachtii to provide a platform for the first system-wide dual analysis of host and parasite gene expression over time, covering all major parasitism stages. Analysis of the hologenome of the plant-nematode infection site identified metabolic pathways that were incomplete in the parasite but complemented by the host. Using a combination of bioinformatic, genetic, and biochemical approaches, we show that a highly atypical completion of vitamin B5 biosynthesis by the parasitic animal, putatively enabled by a horizontal gene transfer from a bacterium, is required for full pathogenicity. Knockout of either plant-encoded or now nematode-encoded steps in the pathway significantly reduces parasitic success. Our experiments establish a reference for cyst nematodes, further our understanding of the evolution of plant-parasitism by nematodes, and show that congruent differential expression of metabolic pathways in the infection hologenome represents a new way to find nematode susceptibility genes. The approach identifies genome-editing-amenable targets for future development of nematode-resistant crops.

The Arabidopsis transcription factor TCP9 modulates root architectural plasticity, reactive oxygen species-mediated processes, and tolerance to cyst nematode infections.

Infections by root-feeding nematodes have profound effects on root system architecture and consequently shoot growth of host plants. Plants harbor intraspecific variation in their growth responses to belowground biotic stresses by nematodes, but the underlying mechanisms are not well understood. Here, we show that the transcription factor TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR-9 (TCP9) modulates root system architectural plasticity in Arabidopsis thaliana in response to infections by the endoparasitic cyst nematode Heterodera schachtii. Young seedlings of tcp9 knock-out mutants display a significantly weaker primary root growth inhibition response to cyst nematodes than wild-type Arabidopsis. In older plants, tcp9 reduces the impact of nematode infections on the emergence and growth of secondary roots. Importantly, the altered growth responses by tcp9 are most likely not caused by less biotic stress on the root system, because TCP9 does not affect the number of infections, nematode development, and size of the nematode-induced feeding structures. RNA-sequencing of nematode-infected roots of the tcp9 mutants revealed differential regulation of enzymes involved in reactive oxygen species (ROS) homeostasis and responses to oxidative stress. We also found that root and shoot growth of tcp9 mutants is less sensitive to exogenous hydrogen peroxide and that ROS accumulation in nematode infection sites in these mutants is reduced. Altogether, these observations demonstrate that TCP9 modulates the root system architectural plasticity to nematode infections via ROS-mediated processes. Our study further points at a novel regulatory mechanism contributing to the tolerance of plants to root-feeding nematodes by mitigating the impact of belowground biotic stresses.

The Autophagy, Inflammation and Metabolism Center international eSymposium - an early-career investigators' seminar series during the COVID-19 pandemic.

The Autophagy, Inflammation and Metabolism (AIM) Center organized a globally accessible, virtual eSymposium during the COVID-19 pandemic in 2020. The conference included presentations from scientific leaders, as well as a career discussion panel, and provided a much-needed platform for early-career investigators (ECIs) to showcase their research in autophagy. This Perspective summarizes the science presented by the ECIs during the event and discusses the lessons learned from a virtual meeting of this kind during the pandemic. The meeting was a learning experience for all involved, and the ECI participants herein offer their thoughts on the pros and cons of virtual meetings as a modality, either as standalone or hybrid events, with a view towards the post-pandemic world.

Macroautophagy and aging: The impact of cellular recycling on health and longevity.

Aging is associated with many deleterious changes at the cellular level, including the accumulation of potentially toxic components that can have devastating effects on health. A key protective mechanism to this end is the cellular recycling process called autophagy. During autophagy, damaged or surplus cellular components are delivered to acidic vesicles called lysosomes, that secure degradation and recycling of the components. Numerous links between autophagy and aging exist. Autophagy declines with age, and increasing evidence suggests that this reduction plays important roles in both physiological aging and the development of age-associated disorders. Studies in pharmacologically and genetically manipulated model organisms indicate that defects in autophagy promote age-related diseases, and conversely, that enhancement of autophagy has beneficial effects on both healthspan and lifespan. Here, we review our current understanding of the role of autophagy in different physiological processes and their molecular links with aging and age-related diseases. We also highlight some recent advances in the field that could accelerate the development of autophagy-based therapeutic interventions.

LC3B phosphorylation: autophagosome's ticket for a ride toward the cell nucleus.

Macroautophagy/autophagy is a multi-step process that leads to cargo degradation via the fusion of hydrolases-containing lysosomes with cargo-loaded autophagosomes. For this process to occur, autophagosomes are directionally transported by molecular motors toward the nucleus, where they fuse with lysosomes for cargo degradation. The molecular basis for this regulation, including the cell machinery required for this directional transport, has not been fully identified. Using a combination of proteomic and live-imaging approaches in mammalian cells, including primary neurons, we describe that the phosphorylation of the autophagosome protein Atg8/LC3B by the Hippo kinase STK4/MST1, an event we previously reported to be required for autophagy completion, reduces the binding of the transport-related protein FYCO1 to MAP1LC3B/LC3B. This event in turn allows the proficient microtubule-based transport of autophagosomes toward the perinuclear area, thus facilitating the contact of autophagosomes with lysosomes. In the absence of LC3B phosphorylation, autophagosomes undergo aberrant transport including increased movement toward the cell periphery resulting in reduced autophagosome-lysosome colocalization. Thus, LC3B phosphorylation modulates the directional transport of autophagosomes to meet with lysosomes in the perinuclear area, a crucial event in ensuring autophagic degradation of cargo.

Systemic Inflammatory Response Syndrome is Associated with Hematoma Expansion in Intracerebral Hemorrhage.

OBJECTIVES: Systemic inflammatory response syndrome (SIRS) and hematoma expansion are independently associated with worse outcomes after intracerebral hemorrhage (ICH), but the relationship between SIRS and hematoma expansion remains unclear. MATERIALS AND METHODS: We performed a retrospective review of patients admitted to our hospital from 2013 to 2020 with primary spontaneous ICH with at least two head CTs within the first 24 hours. The relationship between SIRS and hematoma expansion, defined as ≥6 mL or ≥33% growth between the first and second scan, was assessed using univariable and multivariable regression analysis. We assessed the relationship of hematoma expansion and SIRS on discharge mRS using mediation analysis. RESULTS: Of 149 patients with ICH, 83 (56%; mean age 67±16; 41% female) met inclusion criteria. Of those, 44 (53%) had SIRS. Admission systolic blood pressure (SBP), temperature, antiplatelet use, platelet count, initial hematoma volume and rates of infection did not differ between groups (all p>0.05). Hematoma expansion occurred in 15/83 (18%) patients, 12 (80%) of whom also had SIRS. SIRS was significantly associated with hematoma expansion (OR 4.5, 95% CI 1.16 - 17.39, p= 0.02) on univariable analysis. The association remained statistically significant after adjusting for admission SBP and initial hematoma volume (OR 5.72, 95% CI 1.40 - 23.41, p= 0.02). There was a significant indirect effect of SIRS on discharge mRS through hematoma expansion. A significantly greater percentage of patients with SIRS had mRS 4-6 at discharge (59 vs 33%, p=0.02). CONCLUSION: SIRS is associated with hematoma expansion of ICH within the first 24 hours, and hematoma expansion mediates the effect of SIRS on poor outcome.

LC3B phosphorylation regulates FYCO1 binding and directional transport of autophagosomes.

Macroautophagy (hereafter referred to as autophagy) is a conserved process that promotes cellular homeostasis through the degradation of cytosolic components, also known as cargo. During autophagy, cargo is sequestered into double-membrane vesicles called autophagosomes, which are predominantly transported in the retrograde direction to the perinuclear region to fuse with lysosomes, thus ensuring cargo degradation.1 The mechanisms regulating directional autophagosomal transport remain unclear. The ATG8 family of proteins associates with autophagosome membranes2 and plays key roles in autophagy, including the movement of autophagosomes. This is achieved via the association of ATG8 with adaptor proteins like FYCO1, involved in the anterograde transport of autophagosomes toward the cell periphery.1,3-5 We previously reported that phosphorylation of LC3B/ATG8 on threonine 50 (LC3B-T50) by the Hippo kinase STK4/MST1 is required for autophagy through unknown mechanisms.6 Here, we show that STK4-mediated phosphorylation of LC3B-T50 reduces the binding of FYCO1 to LC3B. In turn, impairment of LC3B-T50 phosphorylation decreases starvation-induced perinuclear positioning of autophagosomes as well as their colocalization with lysosomes. Moreover, a significantly higher number of LC3B-T50A-positive autophagosomes undergo aberrant anterograde movement to axonal tips in mammalian neurons and toward the periphery of mammalian cells. Our data support a role of a nutrient-sensitive STK4-LC3B-FYCO1 axis in the regulation of the directional transport of autophagosomes, a key step of the autophagy process, via the post-translational modification of LC3B.

Sedentary Plant-Parasitic Nematodes Alter Auxin Homeostasis via Multiple Strategies.

Sedentary endoparasites such as cyst and root-knot nematodes infect many important food crops and are major agro-economical pests worldwide. These plant-parasitic nematodes exploit endogenous molecular and physiological pathways in the roots of their host to establish unique feeding structures. These structures function as highly active transfer cells and metabolic sinks and are essential for the parasites' growth and reproduction. Plant hormones like indole-3-acetic acid (IAA) are a fundamental component in the formation of these feeding complexes. However, their underlying molecular and biochemical mechanisms are still elusive despite recent advances in the field. This review presents a comprehensive overview of known functions of various auxins in plant-parasitic nematode infection sites, based on a systematic analysis of current literature. We evaluate multiple aspects involved in auxin homeostasis in plants, including anabolism, catabolism, transport, and signalling. From these analyses, a picture emerges that plant-parasitic nematodes have evolved multiple strategies to manipulate auxin homeostasis to establish a successful parasitic relationship with their host. Additionally, there appears to be a potential role for auxins other than IAA in plant-parasitic nematode infections that might be of interest to be further elucidated.

Beyond Autophagy: The Expanding Roles of ATG8 Proteins.

The ATG8 family proteins are critical players in autophagy, a cytoprotective process that mediates degradation of cytosolic cargo. During autophagy, ATG8s conjugate to autophagosome membranes to facilitate cargo recruitment, autophagosome biogenesis, transport, and fusion with lysosomes, for cargo degradation. In addition to these canonical functions, recent reports demonstrate that ATG8s are also delivered to single-membrane organelles, which leads to highly divergent degradative or secretory fates, vesicle maturation, and cargo specification. The association of ATG8s with different vesicles involves complex regulatory mechanisms still to be fully elucidated. Whether individual ATG8 family members play unique canonical or non-canonical roles, also remains unclear. This review summarizes the many open molecular questions regarding ATG8s that are only beginning to be unraveled.

Cerebral Venous Sinus Thrombosis in the COVID-19 Pandemic.

BACKGROUND: Recent studies have noted concern for increased thromboembolic events in the setting of Coronavirus Disease 2019 (COVID-19). Cerebral venous sinus thrombosis (CVST) is a form of thromboembolism that has been observed as a neuro-ophthalmologic complication of COVID-19. METHODS: Review of the scientific literature. RESULTS: In this article, we report an overview of CVST epidemiology, clinical presentation, diagnostics, disease pathophysiology, and management in the setting of COVID-19. CONCLUSION: CVST is an uncommon thromboembolic event with variable phenotypes and multiple etiologies. Neurologic complications can be severe, including significant visual deficits and death. Current observations suggest that the risk of CVST may be profoundly impacted by this novel COVID-19 pandemic, thus prompting increased attention to disease presentation, pathogenesis, and management.

The production of national defense and the macroeconomy.

This study investigates the interactions between defense production and the rest of the economy. We develop a two-sector dynamic stochastic general equilibrium model with military and nonmilitary production. Inputs (capital and labor) are distributed between the two sectors. Calibration of the model to key targets of the US economy results in an elasticity of substitution between consumption of goods and services and national defense services of 0.56. The estimated complementarity between consumption goods and defense services results in positive spillovers across military and final goods production sectors, even when the nonmilitary production function is not directly related to military spending. We find that military spending is procyclical and that military spending as a percentage of output is countercyclical. Finally, investment-specific technological shocks to military equipment have a positive impact on nonmilitary output, although they reduce business investment.