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Global climate change leads to simultaneous changes in multiple environmental drivers in the marine realm. Although physiological characterization of coccolithophores has been studied under climate change, there is limited knowledge on the biochemical responses of this biogeochemically important phytoplankton group to changing multiple environmental drivers. Here, we investigate the interactive effects of reduced phosphorus availability (4 to 0.4 µmol L−1), elevated pCO2 concentrations (426 to 946 µatm), and increasing light intensity (40 to 300 µmol photons m−2 s−1) on elemental content and macromolecules of the cosmopolitan coccolithophore Emiliania huxleyi. Reduced phosphorus availability reduces particulate organic nitrogen (PON) and protein contents per cell under 40 µmol photons m−2 s−1 but not under 300 µmol photons m−2 s−1. Reduced phosphorus availability and elevated pCO2 concentrations act synergistically to increase particulate organic carbon (POC) and carbohydrate contents per cell under 300 µmol photons m−2 s−1 but not under 40 µmol photons m−2 s−1. Reduced phosphorus availability, elevated pCO2 concentrations, and increasing light intensity act synergistically to increase the allocation of POC to carbohydrates. Under elevated pCO2 concentrations and increasing light intensity, enhanced carbon fixation could increase carbon storage in the phosphorus-limited regions of the oceans where E. huxleyi dominates the phytoplankton assemblages. In each type of light intensity, elemental-carbon-to-phosphorus (C:P) and nitrogen-to-phosphorus (N:P) ratios decrease with increasing growth rate. These results suggest that coccolithophores could reallocate chemical elements and energy to synthesize macromolecules efficiently, which allows them to regulate their elemental content and growth rate to acclimate to changing environmental conditions.

Global climate change leads to simultaneous changes in multiple environmental drivers in the marine realm. Although physiological characterization of coccolithophores has been studied under climate change, there is limited knowledge on the biochemical responses of this biogeochemically important phytoplankton group to changing multiple environmental drivers. Here, we investigate the interactive effects of reduced phosphorus availability (4 to 0.4 µmol L−1), elevated pCO2 concentrations (426 to 946 µatm), and increasing light intensity (40 to 300 µmol photons m−2 s−1) on elemental content and macromolecules of the cosmopolitan coccolithophore Emiliania huxleyi. Reduced phosphorus availability reduces particulate organic nitrogen (PON) and protein contents per cell under 40 µmol photons m−2 s−1 but not under 300 µmol photons m−2 s−1. Reduced phosphorus availability and elevated pCO2 concentrations act synergistically to increase particulate organic carbon (POC) and carbohydrate contents per cell under 300 µmol photons m−2 s−1 but not under 40 µmol photons m−2 s−1. Reduced phosphorus availability, elevated pCO2 concentrations, and increasing light intensity act synergistically to increase the allocation of POC to carbohydrates. Under elevated pCO2 concentrations and increasing light intensity, enhanced carbon fixation could increase carbon storage in the phosphorus-limited regions of the oceans where E. huxleyi dominates the phytoplankton assemblages. In each type of light intensity, elemental-carbon-to-phosphorus (C:P) and nitrogen-to-phosphorus (N:P) ratios decrease with increasing growth rate. These results suggest that coccolithophores could reallocate chemical elements and energy to synthesize macromolecules efficiently, which allows them to regulate their elemental content and growth rate to acclimate to changing environmental conditions.

Alkaline phosphatase (AP) in plants and algae is known to hydrolyze dissolved organophosphate (DOP) in order to obtain phosphorus when the preferred dissolved inorganic phosphorus (DIP) is present in limited supply. By conducting comparative analyses of physiologies and transcriptomes on a mutant of PhoA type AP (mPhoA) and wild type (WT) of the marine diatom Phaeodactylum tricornutum CCAP 1055/1 under P-replete and P-depleted conditions, we document other roles of this gene than DOP scavenging. PhoA mutation created by CRISPR/Cas9 diminished its DOP hydrolase activity but led to significant increases in cellular contents of pigment, carbon, and lipids, photosynthetic rate, growth rate, and the transcriptional levels of their corresponding metabolic pathways. All the results in concert indicate that besides P-nutrient scavenging under DIP deficiency, AP also functions, under the P-replete condition, to constrain pigment biosynthesis, photosynthesis, fatty acid biosynthesis, and cell division. These functions have important implications in maintaining metabolic homeostasis and preventing premature cell division.

The effects of ocean acidification on ecosystems remain poorly understood, because it is difficult to simulate the effects of elevated CO2 on entire marine communities. Natural systems enriched in CO2 are being used to help understand the long-term effects of ocean acidification in situ. Here, we compared biofilm bacterial communities on intertidal cobbles/boulders and bedrock along a seawater CO2 gradient off Japan. Samples sequenced for 16S rRNA showed differences in bacterial communities with different pCO2 and between habitat types. In both habitats, bacterial diversity increased in the acidified conditions. Differences in pCO2 were associated with differences in the relative abundance of the dominant phyla. However, despite the differences in community composition, there was no indication that these changes would be significant for nutrient cycling and ecosystem function. As well as direct effects of seawater chemistry on the biofilm, increased microalgal growth and decreased grazing may contribute to the shift in bacterial composition at high CO2, as documented by other studies. Thus, the effects of changes in bacterial community composition due to globally increasing pCO2 levels require further investigation to assess the implications for marine ecosystem function. However, the apparent lack of functional shifts in biofilms along the pCO2 gradient is a reassuring indicator of stability of their ecosystem functions in shallow ocean margins.

The rise of atmospheric pCO

Objective: This study is to assess the application value of information-based health education and continuity of care in patients with PU (peptic ulcer).Methods: Patients (116) with PU who have been treated in the hospital between January 2019 and October 2020 were taken as research objects and equally assigned to a control group and an observation group in a random manner. In contrast to the routine care applied to the control group, the observation group received information-based health education and continuity of care intervention. The clinical efficacy, the mastery of health knowledge, self-care ability, medication compliance, quality of life, mental state, and nursing satisfaction of the two groups were compared.Results: After the intervention, the total effective rate, health knowledge adequate rate, Exercise of Self-Care Agency (ESCA) scores of all dimensions, the MOS 36-item short-form health survey (SF-36) scores of all dimensions, medication compliance rate, and total nursing satisfaction of the observation group all notably exceeded those of the control group, with a p < 0.05. Patients of the group with continuity of care intervention showed lower Self-Rating Anxiety Scale (SAS) and Self-Rating Depression Scale (SDS) scores, as compared to the group with conventional care (p < 0.05).Conclusion: Information-based health education and continuity of care elevates the medication adherence and nursing satisfaction of patients with PU, enhances disease-related knowledge of patients and their self-care ability, and eventually ameliorates the quality of life and psychological state. It is worthy of clinical application.

The effects of seawater temperature on the physiological performance of three Halimeda species were studied for a period of 28 d. Five treatments were established for Halimeda cylindracea, Halimeda opuntia and Halimeda lacunalis, in triplicate aquaria representing a factorial temperature with 24°C, 28°C, 32°C, 34°C and 36°C, respectively. The average Fv/Fm of these species ranged from 0.732 to 0.756 between 24°C and 32°C but declined sharply between 34°C (0.457±0.035) and 36°C (0.122±0.014). Calcification was highest at 28°C, with net calcification rates (Gnet) of (20.082±2.482) mg/(g•d), (12.825±1.623) mg/(g•d) and (6.411±1.029) mg/(g•d) for H. cylindracea, H. opuntia and H. lacunalis, respectively. Between 24°C and 32°C, the specific growth rate (SGR) of H. lacunalis (0.079%–0.110% d–1) was lower than that of H. cylindracea (0.652%–1.644% d–1) and H. opuntia (0.360%–1.527% d–1). Three Halimeda species gradually bleached at 36°C during the study period. Malondialdehyde (MDA) and proline levels in tissues of the three Halimeda were higher in 34–36°C than those in 24–32°C. The results indicate that seawater temperature with range of 24–32°C could benefit the growth and calcification of these Halimeda species, however, extreme temperatures above 34°C have negative impacts. The measured physiological parameters also revealed that H. cylindracea and H. opuntia displayed broader temperature tolerance than H. lacunalis.

Marine heatwaves (MHWs) are affecting the survival of macroalgae. However, little is known regarding how the impacts of MHWs are regulated by nitrogen availability. In this study, we investigated the physiological and genetic responses of a green-tide macroalga Ulva intestinalis Linnaeus and a commercially cultivated macroalga Gracilariopsis lemaneiformis (Bory) E.Y. Dawson, AcletoFoldvik under different nitrate conditions to simulated MHWs. Under nitrogen limited conditions (LN), heatwaves did not significantly affect biomass or Fv/Fm of U. intestinalis although it led to an earlier biomass decline due to more reproduction events, and meanwhile an upregulation in genes related to TCA cycle and oxidative phosphorylation was detected, supporting sporulation. Under nitrogen replete conditions (HN), heatwaves did not change biomass, Fv/Fm or photosynthetic pigments but reduced reproduction rate along with insignificant change of oxidative phosphorylation and TCA cycle related genes. Meanwhile, genes related to photosynthesis and glutathione metabolism were upregulated. Regarding G. lemaneiformis, heatwaves reduced its Fv/Fm and photosynthetic pigments content, leading to bleaching and death, and photosynthesis-related genes were also downregulated at LN. Fv/Fm was improved and photosynthesis-related genes were up-regulated by the combination of nitrogen enrichment and heatwaves, whereas G. lemaneiformis remained bleached and died by day 12. Therefore, U. intestinalis could survive heatwaves through shifting to micropropagules at LN and protecting its photosynthesis at HN. In contrast, G. lemaneiformis died of bleaching when suffering heatwaves regardless of nitrogen availability. These findings suggest that in future oceans with eutrophication and MHWs, the harmful alga U. intestinalis may have more advantages over the economic alga G. lemaneiformis.

Ultra-short wave network communication is an important means of sea and air cooperation. In this paper, the mathematic model of ultrashort wave communication coverage is established by studying the influence of topography on the site communication coverage. On this basis, according to the principle of minimum blind zone and shortest voyage of aircraft route communication, and based on the aircraft out relevant information, the route planning model of fighter combat is established, in order to efficiently use the resources of space, time and frequency.

PURPOSE. To evaluate the circumstances of corneal sub-basal nerves (CSNs) in the affected and contralateral unaffected eyes of patients with unilateral Posner-Schlossman Syndrome (PSS) through in vivo laser scanning confocal microscopy (LSCM) analysis. METHODS. Total 74 eyes from 37 unilateral PSS patients and 38 eyes of control subjects were recruited. Sub-basal corneal nerve parameters in the in vivo LSCM, including the number and density of total nerves, main nerve trunks, and nerve branches were evaluated. Corneal epithelial and endothelial cell densities were also calculated.RESULTS. The affected eyes of the patients with unilateral PSS demonstrated a significant decrease in all CSN parameters (PPP Yet, significant reduction could only be observed in the affected and contralateral unaffected eyes of the patients with recurrent unilateral PSS. In addition, a positive correlation was found between endothelial cell density and the density of main nerve trunks in PSS-affected eyes (r = 0.33, PCONCLUSIONS. In vivo LSCM analysis revealed the reduction of CSNs in the affected and contralateral unaffected eyes of the patients with recurrent unilateral PSS. The positive correlation between corneal endothelial cell density and CSNs could suggest a potential link between corneal innervation and corneal endothelial cells.Retrospectively registered ChiCTR2000037630, August 29, 2020

Many marine organisms are exposed to decreasing O2 levels due to warming-induced expansion of hypoxic zones and ocean deoxygenation (DeO2). Nevertheless, effects of DeO2 on phytoplankton have been neglected due to technical bottlenecks on examining O2 effects on O2-producing organisms. Here we show that lowered O2 levels increased primary productivity of a coastal phytoplankton assemblage, and enhanced photosynthesis and growth in the coastal diatom Thalassiosira weissflogii. Mechanistically, reduced O2 suppressed mitochondrial respiration and photorespiration of T. weissflogii, but increased the efficiency of their CO2 concentrating mechanisms (CCMs), effective quantum yield and improved light use efficiency, which was apparent under both ambient and elevated CO2 concentrations leading to ocean acidification (OA). While the elevated CO2 treatment partially counteracted the effect of low O2 in terms of CCMs activity, reduced levels of O2 still strongly enhanced phytoplankton primary productivity. This implies that decreased availability of O2 with progressive DeO2 could boost re-oxygenation by diatom-dominated phytoplankton communities, especially in hypoxic areas, with potentially profound consequences for marine ecosystem services in coastal and pelagic oceans., Sun et al. investigate the effects of current ambient and potential future oxygen levels on phytoplankton growth and photosynthesis with field observations and mesocosm and lab experiments. Their results demonstrate positive effects of low O2 on phytoplankton growth, photosynthesis, and inorganic carbon acquisition at current and future high levels of CO2.

The identification and location of the marine moving object is a basic problem for the passive radars and it is widely used in the fields of ocean escort and salvage. In the background of our army's survey of the marine moving object, the research methods for two-ship and single ship passive locating are studied. The models of moving state for the target ship are established by the azimuth angle. Meanwhile, the possible inaccuracy is also analyzed in this essay.

There is increasing concern about the effects of ocean acidification on marine biogeochemical and ecological processes and the organisms that drive them, including marine bacteria. Here, we examine the effects of elevated CO2 on the bacterioplankton community during a mesocosm experiment using an artificial phytoplankton community in subtropical, eutrophic coastal waters of Xiamen, southern China. Through sequencing the bacterial 16S rRNA gene V3-V4 region, we found that the bacterioplankton community in this high-nutrient coastal environment was relatively resilient to changes in seawater carbonate chemistry. Based on comparative ecological network analysis, we found that elevated CO2 hardly altered the network structure of high-abundance bacterioplankton taxa but appeared to reassemble the community network of low abundance taxa. This led to relatively high resilience of the whole bacterioplankton community to the elevated CO2 level and associated chemical changes. We also observed that the Flavobacteria group, which plays an important role in the microbial carbon pump, showed higher relative abundance under the elevated CO2 condition during the early stage of the phytoplankton bloom in the mesocosms. Our results provide new insights into how elevated CO2 may influence bacterioplankton community structure.

In this paper, an optimization model and the corresponding algorithm are obtained, which require the minimum amount of time and work to irrigate a given field by using this type of irrigation system. We can find the number of sprinklers and the spacing for each of the sprinklers, which can insure the system to provide uniform water coverage. Lastly, we determine a schedule to move the pipes, including where to move them.

By combining the central manifold theorem and planar bifurcation theory, this paper studies the bifurcation limit cycles of a class of three dimensional systems with homology rings, gives the conditions for the existence of stable limit cycles, and generalizes the results of existing planar systems.

The effects of ocean acidification on ecosystems remain poorly understood, because it is difficult to simulate the effects of elevated CO

In order to study the natural contamination deposited characteristics of insulators in salt lakes of Qinghai, China, sampling of insulator contamination was carried out on 750kV Chai-Yu I, II line and 330kV Ge-Yan line in Chaerhan Salt Lake area. The characteristic values such as equivalent salt density (ESDD), gray density (NSDD), gray salt ratio, coefficient on uneven distribution of upper and lower surfaces (K E ,K N ) were obtained from the test point, and the difference of pollution accumulation where inside and outside the salt lake area was compared. Furthermore, the chemical composition of the salt lake and saline-alkali land was measured, and analyzed the composition and content of soluble salt and insoluble substances in pollution layer on insulator Surface. The results show that the pollution level reaches above d and e both in salt lake and its vicinity, and the contamination on the surface of the insulator is rapidly accumulated in the salt lake environment. The ratio of gray to salt tends to be concentrated and less than 1, and the ratio on composite insulator is 2 to 3 times than porcelain. The degree of contamination on bottom surface of each shed is much larger than that of the top surface, and the average values of K E and K N are 2.33 and 1.42 respectively. The components of the pollution are mainly composed of CaSO 4 , NaCl and CaCl 2 , the insoluble matter are mainly CaO, SiO 2 , Fe 2 O 3 , and the coefficient of effective ESDD in this area can be taken as 0.8.

By combining the means of the center manifold theorem and Planar branching theory, this paper studies the sufficient conditions for general three-dimensional systems to branch out into spatial periodic solutions under mixed perturbations, and obtains two theorems for judging the periodic solutions of general three-dimensional systems branching out from closed orbits, which generalize the results of existing planar systems.

Understanding of the molecular responses underpinning diatom responses to ocean acidification is fundamental for predicting how important primary producers will be shaped by the continuous rise in atmospheric CO2. In this study, we have analyzed global transcriptomic changes of the model diatom Phaeodactylum tricornutum following growth for 15 generations in elevated pCO2 by strand-specific RNA sequencing (ssRNA-seq). Our results indicate that no significant effects of elevated pCO2 and associated carbonate chemistry changes on the physiological performance of the cells were observed after 15 generations whereas the expression of genes encoding histones and other genes involved in chromatin structure were significantly down-regulated, while the expression of transposable elements (TEs) and genes encoding histone acetylation enzymes were significantly up-regulated. Furthermore, we identified a series of long non-protein coding RNAs (lncRNAs) specifically responsive to elevated pCO2, suggesting putative regulatory roles for these largely uncharacterized genome components. Taken together, our integrative analyses reveal that epigenetic elements such as TEs, histone modifications and lncRNAs may have important roles in the acclimation of diatoms to elevated pCO2 over short time scales and thus may influence longer term adaptive processes in response to progressive ocean acidification.

In this paper, for large and medium-sized traffic circles with heavy traffic volumes, an ordinary signalized model and a two-way stop-control model are established. It can realize the optimized volume control of a traffic circle to improve its capacity and safety, and to reduce its control delay. Finally, an optimized design is made for the time of green traffic-light.

This paper, by combining the central manifold theorem with the plane bifurcation theory, conducted a research on the homoclinic bifurcation limit circles of a class of three-dimensional system. The conditions for the existence of stable limit circles were given, and the results of the existing plane systems were generalized.

The classical functional response function is generalized to a generalized functional response function for a three-group mixed non-autonomous predator system with both predator and competitive relationships. Through the constructor and the qualitative knowledge of ordinary differential equations, this paper studies the continuity and global asymptotic stability of the system and further discusses the existence and stability of the positive almost periodic solution of the system, and obtains sufficient conditions for the existence of unique, globally asymptotically stable positive almost periodic solutions of the system, and the existing conclusions has been extended to a large extent.

There is increasing concern about the effects of ocean acidification on marine biogeochemical and ecological processes and the organisms that drive them, including marine bacteria. Here, we examine the effects of elevated CO2 on bacterioplankton community during a mesocosm experiment using an artificial phytoplankton community in subtropical, eutrophic coastal waters of Xiamen, Southern China. We found that the elevated CO2 hardly altered the network structure of the bacterioplankton taxa present with high abundance but appeared to reassemble the community network of taxa present with low abundance by sequencing of the bacterial 16S rRNA gene V3-V4 region and ecological network analysis. This led to relatively high resilience of the whole bacterioplankton community to the elevated CO2 level and associated chemical changes. We also observed that the Flavobacteriia group, which plays an important role in the microbial carbon pump, showed higher relative abundance under elevated CO2 condition during the developing stage of the phytoplankton bloom in the mesocosms. Compared to the CO2 enrichment, the phytoplankton bloom had more pronounced effects on baterioplankton community structure. Our results suggest that the bacterioplankton community in this subtropical, high nutrient coastal environment is relatively insensitive to changes in seawater carbonate chemistry.

A mesocosm experiment was conducted in Wuyuan Bay (Xiamen), China, to investigate the effects of elevated pCO2 on bloom formation by phytoplankton species previously studied in laboratory-based ocean acidification experiments, to determine if the indoor-grown species performed similarly in mesocosms under more realistic environmental conditions. We measured biomass, primary productivity and particulate organic carbon (POC) as well as particulate organic nitrogen (PON). Phaeodactylum tricornutum outcompeted Thalassiosira weissflogii and Emiliania huxleyi, comprising more than 99% of the final biomass. Mainly through a capacity to tolerate nutrient-limited situations, P. tricornutum showed a powerful sustained presence during the plateau phase of growth. Significant differences between high and low CO2 treatments were found in cell concentration, cumulative primary productivity and POC in the plateau phase but not during the exponential phase of growth. Compared to the low pCO2 (LC) treatment, POC increased by 45.8–101.9% in the high pCO2 (HC) treated cells during the bloom period. Furthermore, respiratory carbon losses of gross primary productivity were found to comprise 39–64% for the LC and 31–41% for the HC mesocosms (daytime C fixation) in phase II. Our results suggest that the duration and characteristics of a diatom bloom can be affected by elevated pCO2. Effects of elevated pCO2 observed in the laboratory cannot be reliably extrapolated to large scale mesocosms with multiple influencing factors, especially during intense algal blooms.

Objectives The purpose of this study was to determine if cholesterol crystals can injure the endothelial surface by their jagged edges altering vasoreactivity and contributing to no-reflow after intervention. Background After plaque rupture, cholesterol crystals are released into the circulation and flow downstream contacting the arterial wall. Methods Both carotid arteries from 22 rabbits were placed in a dual perfusion chamber and challenged with norepinephrine followed by acetylcholine and nitroprusside. Arterial diameters were measured before and after exposure to cholesterol crystals or microspheres and compared with diameters of normal control arteries. Arteries were examined by light, confocal, atomic force and scanning electron microscopy. Results Pre-exposure mean arterial diameter was 2.33 ± 0.27 mm. With baseline norepinephrine there was vasoconstriction of 0.82 ± 0.19 mm, 0.79 ± 0.18 mm, and 0.83 ± 0.16 mm in lumen diameter in the crystal, microsphere, and control groups, respectively. After cholesterol crystals or microspheres, vasoconstriction was significantly less for cholesterol crystals but not for microspheres (0.71 ± 0.28 mm and 0.81 ± 0.15 mm; p Conclusions Cholesterol crystals damaged the endothelium and reduced vasodilator response, potentially aggravating myocardial ischemia after interventions.

Background— It has been shown that plaque uptake of fluorodeoxyglucose is proportional to macrophage density. We tested the hypothesis that arterial thrombosis occurs in areas with high fluorodeoxyglucose uptake and that computed tomography angiography (CTA) can detect thrombi in vessels. Methods and Results— Twenty New Zealand White rabbits were studied before and after atherosclerosis induction through de-endothelialization and a high-cholesterol diet; 14 were then thrombus triggered. CTA/positron emission tomography scans were performed before cholesterol diet, at the middle diet feeding, at the end of diet feeding, and after triggering. Serum inflammatory markers were measured. Maximal standardized uptake value was measured over the thoracic and upper and lower abdominal aortas and correlated with thrombosis and macrophage density on sections from the same sites. Aortic diameters averaged 2.84±1.16 mm. The sensitivity, specificity, and accuracy of CTA for detecting thrombi were 92%, 89%, and 90%, respectively. Plasminogen activator inhibitor-1 and C-reactive protein levels increased with atherosclerosis and thrombosis triggering. Maximal standardized uptake value at baseline was 0.62±0.13, 0.96±0.33 at the middle of feeding, and 1.06±0.38 at the end of feeding. Segments that developed thrombosis had the highest maximal standardized uptake value of 1.32±0.69 (113% increase; P =0.002) and had a 129% increase in macrophage density compared with segments without thrombi ( P =0.01). Conclusions— Fluorodeoxyglucose uptake was proportional to the duration of cholesterol feeding and peaked with plaque disruption and thrombosis. CTA was highly accurate in detecting thrombi. Our findings in this animal model of atherosclerotic plaques with high macrophage density showed that CTA/positron emission tomography can be used to identify and localize inflamed plaques and thrombosis. With the currently available technology and nuclear tracers, however, many challenges remain before clinical applications are possible.

Background and Objectives Excimer laser is used clinically in arterial revascularization procedures. This study evaluated the efficacy of aspirin in reducing platelet aggregation during high-energy excimer lasing. Study Design/Materials and Methods Platelet rich plasma (PRP) from seven rabbits was circulated in a dual organ chamber with aspirin added to one and the other was control. PRP was irradiated using an excimer laser (308 nm; 45 mJ/mm2; 25 Hz; 5 minutes) via a 2.0 mm laser catheter. Platelet aggregation (particle volume) was measured by laser-light scattering. Morphology was evaluated by phase contrast and electron microscopy. Results Baseline platelet volume was 3.4 µm3 for both control and aspirin groups. Following lasing, platelet volume peaked at 102.2 ± 18.5 µm3 for control compared to 43.1 ± 49.2 µm3 for aspirin-treated PRP (P

We recently obtained evidence that cocaine- and amphetamine-regulated transcript (CART), a potent anorectic neuropeptide, is expressed in the bovine ovary. The objectives of this study were to characterize bovine ovarian CART and determine its localization, regulation, and regulatory role during follicular development. CART mRNA was detected in stroma of adult ovaries and in large follicles, but was undetectable in several peripheral tissues, fetal ovaries, and corpora lutea. Within the ovary, CART mRNA and peptide were localized to the granulosal layer of some, but not all, antral follicles, with low, but detectable, expression in oocytes and cumulus cells. CART mRNA was undetectable in granulosal cells of dominant ovulatory follicles collected before and after the preovulatory gonadotropin surge, but was detected in the granulosal layer of adjacent subordinate follicles. In addition, amounts of CART mRNA and follicular fluid concentrations of CART peptide were greater in subordinate follicles vs. dominant follicles of the first follicular wave. Furthermore, CART treatment inhibited basal estradiol production, but not progesterone production, by granulosal cells in a dose-dependent fashion, and the effect was dependent on stage of cell differentiation. We conclude that granulosal cell CART expression is temporally regulated and potentially associated with follicle health status, and CART can inhibit granulosal cell estradiol production. Thus, CART may be a novel local regulator of follicular atresia in the bovine ovary.