The Cys-2088-Arg mutation in the ACCase gene and enhanced metabolism confer cyhalofop-butyl resistance in Chinese sprangletop (Leptochloa chinensis).

Acetyl-CoA carboxylase (ACCase)-inhibiting herbicides are among the most commonly used herbicides to control grassy weeds, especially Leptochloa chinensis, in rice fields across China. Herein, we collected a suspected resistant (R) population of L. chinensis (HFLJ16) from Lujiang county in Anhui Province. Whole plant dose response tests showed that, compared with the susceptible (S) population, the R population showed high resistance to cyhalofop-butyl (22-fold) and displayed cross-resistance to metamifop (9.7-fold), fenoxaprop-P-ethyl (18.7-fold), quizalofop-P-ethyl (7.6-fold), clodinafop-propargyl (12-fold) and clethodim (8.4-fold). We detected an amino acid substitution (Cys-2088-Arg) in the ACCase of resistant L. chinensis. However, ACCase gene expression levels were not significantly different (P > 0.05) between R plants and S plants, without or with cyhalofop-butyl treatment. Furthermore, pretreatment with piperonyl butoxide (PBO, a cytochrome P450 monooxygenase (CYP450) inhibitor) or 4-chloro-7-nitrobenzoxadiazole (NBD-Cl, a glutathione-S-transferase (GST) inhibitor), inhibited the resistance of the R population to cyhalofop-butyl significantly (by approximately 60% and 26%, respectively). Liquid chromatography tandem mass spectrometry analysis showed that R plants metabolized cyhalofop-butyl and cyhalofop acid (its metabolite) significantly faster than S plants. Three CYP450 genes, one GST gene, and two ABC transporter genes were induced by cyhalofop-butyl and were overexpressed in the R population. Overall, GST-associated detoxification, CYP450 enhancement, and target-site gene mutation are responsible for the resistance of L. chinensis to cyhalofop-butyl.

Cytochrome P450s-Involved Enhanced Metabolism Contributes to the High Level of Nicosulfuron Resistance in Digitaria sanguinalis from China.

Large crabgrass (Digitaria sanguinalis (L.) Scop.) is one of the major malignant grass weeds in Chinese maize (Zea mays L.) fields, and it has recently developed resistance to the acetolactate synthase (ALS)-inhibiting herbicide nicosulfuron. This study focused on a suspected nicosulfuron-resistant (R) population (LJ-01) of D. sanguinalis, collected from Lujiang County in Anhui Province, China, to explore the resistance level and potential resistance mechanism. Whole-plant dose-response testing confirmed that the LJ-01 population evolved a high level of resistance to nicosulfuron (11.5-fold) compared to the susceptible (S) population, DY-02. The ALS gene sequencing and relative expression assay of the R plants indicated that target gene mutation and overexpression were not responsible for the resistance phenotype. However, pretreatment with malathion, a known cytochrome P450 monooxygenase (P450) inhibitor, alleviated the resistance of the R population to nicosulfuron by approximately 36%. High-performance liquid chromatography (HPLC) analysis revealed that the R plants metabolized nicosulfuron faster than the S plants. Moreover, cross-resistance testing suggested that the R population exhibited low levels of resistance to thifensulfuron-methyl and pyrazosulfuron-ethyl, but it remained susceptible to rimsulfuron. Multiple resistance patterns showed that the R population evolved low resistance to the photosystem inhibitors bromoxynil octanoate and atrazine and sensitivity to the acetyl-CoA carboxylase (ACCase) inhibitor cyhalofop-butyl and the 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors tembotrione, mesotrione, and topramezone. This study reports, for the first time, the simultaneous resistance to ALS and different photosystem inhibitors in D. sanguinalis. The nicosulfuron resistance observed in the R population could primarily be attributed to an enhanced metabolism involving P450 enzymes.

Altered resting-state brain activity in major depressive disorder comorbid with subclinical hypothyroidism: A regional homogeneity analysis.

BACKGROUND: Major depressive disorder (MDD), a common mental disorder worldwide, frequently coexists with various physical illnesses, and recent studies have shown an increased prevalence of subclinical hypothyroidism (SHypo) among MDD patients. However, the neural mechanisms shared and unique to these disorders and the associated alterations in brain function remain largely unknown. This study investigated the potential brain function mechanisms underlying comorbid MDD and SHypo. METHOD: Thirty MDD patients (non-comorbid group), 30 MDD patients comorbid with SHypo (comorbid group), 26 patients with SHypo, and 30 healthy controls were recruited for resting-state functional magnetic resonance imaging (rs-fMRI). We used regional homogeneity (ReHo) to examine differences in internal cerebral activity across the four groups. RESULTS: Compared with the non-comorbid group, the comorbid group exhibited significantly higher ReHo values in the right orbital part of the middle frontal gyrus (ORBmid) and bilateral middle frontal gyrus; decreased ReHo values in the right middle temporal gyrus, right thalamus, and right superior temporal gyrus, and right insula. Within the comorbid group, serum TSH levels were negatively associated with the ReHo values of the right insula; the ReHo values of the right Insula were negatively associated with the retardation factor score; the ReHo values of the right ORBmid were positively correlated with the anxiety/somatization factor scores. CONCLUSIONS: These findings provide valuable clues for exploring the shared neural mechanisms between MDD and SHypo and have important implications for understanding the pathophysiological mechanisms of the comorbidity of the two disorders.

Attenuated post-movement beta rebound reflects psychomotor alterations in major depressive disorder during a simple visuomotor task: a MEG study.

BACKGROUND: Psychomotor alterations are a common symptom in patients with major depressive disorder (MDD). The primary motor cortex (M1) plays a vital role in the mechanism of psychomotor alterations. Post-movement beta rebound (PMBR) in the sensorimotor cortex is abnormal in patients with motor abnormalities. However, the changes in M1 beta rebound in patients with MDD remain unclear. This study aimed to primarily explore the relationship between psychomotor alterations and PMBR in MDD. METHODS: One hundred thirty-two subjects were enrolled in the study, comprising 65 healthy controls (HCs) and 67 MDD patients. All participants performed a simple right-hand visuomotor task during MEG scanning. PMBR was measured in the left M1 at the source reconstruction level with the time-frequency analysis method. Retardation factor scores and neurocognitive test performance, including the Digit Symbol Substitution Test (DSST), the Making Test Part A (TMT-A), and the Verbal Fluency Test (VFT), were used to measure psychomotor functions. Pearson correlation analyses were used to assess relationships between PMBR and psychomotor alterations in MDD. RESULTS: The MDD group showed worse neurocognitive performance than the HC group in all three neurocognitive tests. The PMBR was diminished in patients with MDD compared to HCs. In a group of MDD patients, the reduced PMBR was negatively correlated with retardation factor scores. Further, there was a positive correlation between the PMBR and DSST scores. PMBR is negatively associated with the TMT-A scores. CONCLUSION: Our findings suggested that the attenuated PMBR in M1 could illustrate the psychomotor disturbance in MDD, possibly contributing to clinical psychomotor symptoms and deficits of cognitive functions.

Gray matter reduction is associated with cognitive dysfunction in depressed patients comorbid with subclinical hypothyroidism.

Introduction: To explore the association between regional gray matter volume (GMV) and cognitive impairments and ascertain whether the regional brain alterations related to cognitive impairments occur in major depressive disorder (MDD) patients with comorbid subclinical hypothyroidism (SHypo). Methods: We enrolled 32 MDD patients, 32 MDD patients with comorbid SHypo, and 32 normal controls and subjected them to thyroid function tests, neurocognitive tests, and magnetic resonance imaging (MRI). Using voxel-based morphometry (VBM) analysis, we examined the pattern of gray matter (GM) in these participants. We also used ANOVA to detect group differences and partial correlation to explore the potential association between GMV alterations and cognitive tests in comorbid patients. Results: The comorbid patients exhibited significantly smaller GMV in the right middle frontal gyrus (MFG) than the non-comorbid group. Furthermore, the partial correlation analysis showed that GMV of the right MFG was associated with poor executive function (EF) performance in comorbid patients. Conclusion: These findings provide valuable insight into the relationship between the alteration of GMV and cognitive dysfunction of MDD patients with comorbid SHypo.

Alterations of regional spontaneous neuronal activity and corresponding brain circuits related to non-suicidal self-injury in young adults with major depressive disorder.

BACKGROUND: Major depressive disorder (MDD) with non-suicidal self-injury (NSSI)(MDD/NSSI) has been found to differ from simple MDD without NSSI (sMDD). This study analyzes the amplitude of low-frequency fluctuations (ALFF) to explore the NSSI-relevant local neural activity, and uses functional connectivity (FC) analysis to explore the NSSI-relevant circuits corresponding to alterations in local regions in young adult patients with MDD/NSSI. METHODS: A total of 54 patients with MDD/NSSI, 68 patients with sMDD, and 66 matched healthy controls (HCs) were recruited. ALFF and seed-based FC analyses were employed. The NSSI-relevant brain alteration and its associations with clinical variables were examined. RESULTS: Compared with the sMDD group, the MDD/NSSI group showed higher ALFF in the right lingual gyrus and right middle occipital gyrus; lower ALFF in the right superior frontal gyrus; higher FC values between the right lingual gyrus and left precentral gyrus; and lower FC values between the right middle occipital gyrus and right paracentral gyrus. Within the MDD/NSSI group, ALFF values of the right superior frontal gyrus and right lingual gyrus were positively correlated with the frequency and severity of NSSI. LIMITATIONS: The sample size was small, and the potential influence of medicine on brain activity was not excluded. CONCLUSIONS: Our preliminary findings indicate that NSSI-relevant ALFF in the right lingual gyrus, right middle occipital gyrus, and right superior frontal gyrus, as well as the alteration FCs in corresponding brain circuits, may play an important role in the neural basis of MDD/NSSI.

Diurnal mood variation symptoms in major depressive disorder associated with evening chronotype: Evidence from a neuroimaging study.

BACKGROUND: Major depressive disorder (MDD) is often accompanied with classic diurnal mood variation (DMV) symptoms. Patients with DMV symptoms feel a mood improvement and prefer activities at dusk or in the evening, which is consistent with the evening chronotype. Their neural alterations are unclear. In this study, we aimed to explore the neuropathological mechanisms underlying the circadian rhythm of mood and the association with chronotype in MDD. METHODS: A total of 126 depressed patients, including 48 with DMV, 78 without, and 67 age/gender-matched healthy controls (HC) were recruited and underwent a resting-state functional magnetic resonance imaging. Spontaneous neural activity was investigated using amplitude of low-frequency fluctuation (ALFF) and region of interest (ROI)-based functional connectivity (FC) analyses were conducted. The Morningness-Eveningness Questionnaire (MEQ) was utilized to evaluate participant chronotypes and Pearson correlations were calculated between altered ALFF/FC values and MEQ scores in patients with MDD. RESULTS: Compared with NMV, DMV group exhibited lower MEQ scores, and increased ALFF values in the right orbital superior frontal gyrus (oSFG). We observed that increased FC between the left suprachiasmatic nucleus (SCN) and supramarginal gyrus (SMG). ALFF in the oSFG and FC of rSCN-SMG were negatively correlated with MEQ scores. LIMITATION: Some people's chronotypes information is missing. CONCLUSION: Patients with DMV tended to be evening type and exhibited abnormal brain functions in frontal lobes. The synergistic changes between frontotemporal lobe, SCN-SMG maybe the characteristic of patients with DMV symptoms.

The Correlation Between Thyroid Function, Frontal Gray Matter, and Executive Function in Patients With Major Depressive Disorder.

The present study was aimed to investigate the relationships between serum thyroid hormones (THs), frontal gray matter volume, and executive function in selected patients with major depressive disorder (MDD). One hundred and four MDD patients and seventy-five healthy controls (HCs) were subjected to thyroid-stimulating hormone (TSH), free Triiodothyronine (fT3), free Thyroxine (fT4), and executive function tests and underwent structural magnetic resonance imaging (MRI). Voxel-based morphometry (VBM) analysis was performed to compare group differences in the gray matter for the frontal lobe. Furthermore, mediation analysis was used to investigate whether gray matter volumes of the frontal gyrus mediated the relationship between serum THs and executive function in MDD patients. MDD patients exhibited significant gray matter volume reduction in several brain regions, including the left rectus, right middle frontal cortex, and left middle frontal cortex. Serum TSH levels are positively associated with altered regional gray matter volume patterns within MFG and executive function. Importantly, gray matter in the right MFG was a significant mediator between serum TSH levels and executive function. These findings expand our understanding of how thyroid function affects brain structure changes and executive function in MDD patients.

Sex differences in the association between symptom profiles and cognitive functioning in patients with depressive disorder.

OBJECTIVE: Depressive disorder (DD) is a heterogeneous disease with sex differences in symptom profiles and cognitive performance. However, sex differences in cognitive dysfunction associated with different symptom profiles have received little systematic study. This study aimed to explore the association between clinical symptoms and cognitive deficits in patients with DD. METHODS: A cohort of 222 hospitalized patients with DD (males/females = 114/108) and 173 healthy controls (males/females = 80/93) were enrolled. Cognitive function was measured using a comprehensive neuropsychological battery. Depression was assessed using the 17-item Hamilton Rating Scale for Depression (HAMD-17). According to different genders, the relationship between symptom profiles and cognitive deficits was identified using partial correlation analysis and multiple regression analysis. RESULTS: Patients with DD performed significantly worse than healthy controls in all cognitive domains investigated (all p < 0.05). Remarkably, female patients scored better than male patients on information processing speed (p < 0.05). Multivariate regression analyses showed that the retardation factor score was independently associated with attention and cognitive flexibility, and the sleep disturbance factor score was independently associated with information processing speed in male patients. Furthermore, the anxiety/somatization factor score was independently associated with working memory in female patients. CONCLUSION: In the present study, we showed that significant sex differences in the association between symptom profiles and cognitive impairment are present in DD patients. Understanding how DD patients' clinical features and cognitive performance are linked from a sex perspective may have clinical implications for predicting and interfering with the outcome of depression.

Increased prevalence of subclinical hypothyroidism in female hospitalized patients with depression.

BACKGROUNDS: Sex differences in depressive disorder (DD) and subclinical hypothyroidism (SCH) have been well recognized. However, few studies focus on the sex differences in DD patients with SCH. The purpose of this study is to address the sex differences in DD inpatients with SCH and further investigate the clinical characteristics and associations between DD and SCH among female and male depressed inpatients. METHODS: A total of 1787 hospitalized patients with a diagnosis of DD were recruited. Depression was assessed using the Hamilton Depression Rating Scale-17 items (HAMD), and anxiety was assessed using the Hamilton Anxiety Rating Scale. Blood test, including serum thyroid hormone levels, was measured. According to different genders, associations between DD and the presence of SCH were estimated using binary logistic regression. RESULTS: In the 1787 hospitalized patients with DD, the prevalence of SCH was 11.8%; the prevalence of SCH in female depressed inpatients is approximately two times that of male inpatients (14.6 vs. 7.4%, P < 0.05). Logistic regression showed that recurrent episodes and high BMI were associated with SCH in female inpatients (both P < 0.05). Spearman correlation analysis showed that thyroid stimulating hormone levels were associated with BMI (P < 0.05), total cholesterol levels (P < 0.05), and low-density lipoprotein cholesterol levels (P < 0.05) in female inpatients. CONCLUSIONS: Our present study showed that the prevalence of SCH among female hospitalized patients with depression is approximately two times that of male inpatients. Recurrent and high-BMI female depressed inpatients are at high risk to develop SCH. More attention should be paid to the thyroid function of female inpatients with DD in future clinical work.