Effects of a manganese complex with lysine and glutamic acid on growth performance, manganese deposition and emission, antioxidant capacity and metacarpal strength in weaned piglets.

The present study sought to assess the effects of manganese complexes with lysine and glutamic acid (Mn-LG) as manganese (Mn) sources on growth performance, trace element deposition, antioxidant capacity, and metacarpal strength in weaned piglets. The study involved 288 healthy Duroc × Landrace × Yorkshire piglets that were weaned at 25-28 days of age and weighed 8.66±0.96 kg. These piglets were randomly divided into six groups: a control group (Mn-LG-0, receiving a basal diet without Mn supplementation), a Mn sulfate group (basal diet supplemented with 40 mg·kg-1 diet of Mn, Mn-S-40 group), and four Mn-LG groups (Mn-LG-20, Mn-LG-40, Mn-LG-60, Mn-LG-80, supplemented with 20, 40, 60, and 80 mg·kg-1 Mn from Mn-LG in the basal diet). Grouping began at weaning as the 0th day of the experiment. The corn-soybean-based basal diet during the early (d 0-14) and late (d 15-42) phases of the experiment contained 20.88 and 30.12 mg·kg-1 Mn, respectively. Blood samples were collected on days 14 and 42, and pigs were sacrificed for sample collection on day 42. The results indicated no significant differences in average daily gain, average daily feed intake, or feed-to-gain ratio among the groups (P > 0.05). The diarrhea rates of all Mn-LG groups and the Mn-S-40 group were significantly lower in the 0-14 d and during the entire experimental period than in the Mn-LG-0 group (P < 0.001). The Mn-LG-40 group exhibited a significant increase in liver Mn concentration and serum Mn superoxide dismutase (Mn-SOD) activity on d 42 (P < 0.01), as well as a significant decrease in fecal Mn concentration (P < 0.05), compared to those of the Mn-S-40 group. Significant differences (P < 0.05) were detected in the serum, liver, and fecal Mn concentrations, as well as in the serum and liver Mn-SOD activity, across the different Mn-LG groups. The serum and fecal Mn concentrations and serum Mn-SOD activity increased linearly or quadratically (P < 0.01) with increasing Mn-LG supplementation. No significant differences (P > 0.05) were found in kidney, heart, or metacarpal bone Mn concentrations or in bone strength indices. In summary, compared with the Mn-LG-0 diet, dietary supplementation with Mn-LG enhanced serum Mn deposition and Mn-SOD activity and decreased the incidence of diarrhea. Additionally, the fecal Mn concentration was lower in the Mn-LG group than in the inorganic group at equivalent dosages.

Imaging and quantification of neuropeptides in mouse pituitary tissue by atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry.

RATIONALE: Atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI) mass spectrometry has enabled the untargeted analysis and imaging of neuropeptides and proteins in biological tissues under ambient conditions. Sensitivity in AP-MALDI can be improved by using sample-specific preparation methods. METHODS: A comprehensive and detailed optimization strategy including instrument parameters, matrix spraying and sample tissue washing pretreatment was implemented to enhance the sensitivity and coverage of neuropeptides in mouse pituitary tissues by commercial AP-MALDI mass spectrometry imaging (MSI). RESULTS: The sensitivity of a commercial AP-MALDI system for endogenous neuropeptides in mouse pituitary was enhanced by up to 15.2-fold by shortening the transmission gap from the sample plate to the inlet, attaching copper adhesive tape to an indium tin oxide-coated glass slide, optimizing the matrix spray solvent and using sample tissue washing pretreatment. Following careful optimization, the distributions of nine endogenous neuropeptides were successfully visualized in the pituitary. Furthermore, the quantitative capability of AP-MALDI for neuropeptides was evaluated and the concentrations of neuropeptides oxytocin and vasopressin in the pituitary posterior lobe were increased approximately twofold under hypertonic saline stress. CONCLUSION: Mouse pituitary neuropeptides have emerged as important signaling molecules due to their role in stress response. This work indicates the potential of modified AP-MALDI as a promising AP MSI method for in situ visualization and quantification of neuropeptides in complex biological tissues.

Development of Transmission Ambient Pressure Laser Desorption Ionization/Postphotoionization Mass Spectrometry Imaging.

Laser-based high-resolution mass spectrometry imaging at ambient conditions has promising applications in life science. However, the ion yield during laser desorption/ablation is poor. Here, transmission atmospheric pressure laser desorption ionization combined with a compact postphotoionization (t-AP-LDI/PI) assembly with a krypton discharge lamp was developed for the untargeted imaging of various biomolecules. The spatial distributions of numerous lipid classes, fatty acids, neurotransmitters, and amino acids in the subregions of mouse cerebellum tissue were obtained. Compared with single laser ablation, the sensitivities for most analytes were increased by 1 to 3 orders of magnitude by dopant-assisted postphotoionization. After careful optimization, a spatial resolution of 4 µm could be achieved for the metabolites in mouse hippocampus tissue. Finally, the melanoma tissue slices were analyzed using t-AP-LDI/PI MSI, which revealed the metabolic heterogeneity of the melanoma microenvironment and exhibited the phenomenon of abnormal proliferation and invasion trends in tumor cells.

Construction of a co-expression network affecting intramuscular fat content and meat color redness based on transcriptome analysis.

Introduction: Intramuscular fat content (IFC) and meat color are vital indicators of pork quality. Methods: A significant positive correlation between IFC and redness of meat color (CIE a* value) indicates that these two traits are likely to be regulated by shared molecular pathways.To identify candidate genes, hub genes, and signaling pathways that regulate these two traits, we measured the IFC and CIE a* value in 147 hybrid pigs, and selected individuls with extreme phenotypes for transcriptome analysis. Results: The results revealed 485 and 394 overlapping differentially expressed genes (DEGs), using the DESeq2, limma, and edgeR packages, affecting the IFC and CIE a* value, respectively. Weighted gene co-expression network analysis (WGCNA) identified four modules significantly correlated with the IFC and CIE a* value. Moreover, we integrated functional enrichment analysis results based on DEGs, GSEA, and WGCNA conditions to identify candidate genes, and identified 47 and 53 candidate genes affecting the IFC and CIE a* value, respectively. The protein protein interaction (PPI) network analysis of candidate genes showed that 5 and 13 hub genes affect the IFC and CIE a* value, respectively. These genes mainly participate in various pathways related to lipid metabolism and redox reactions. Notably, four crucial hub genes (MYC, SOX9, CEBPB, and PPAGRC1A) were shared for these two traits. Discussion and conclusion: After functional annotation of these four hub genes, we hypothesized that the SOX9/CEBPB/PPARGC1A axis could co-regulate lipid metabolism and the myoglobin redox response. Further research on these hub genes, especially the SOX9/CEBPB/PPARGC1A axis, will help to understand the molecular mechanism of the co-regulation of the IFC and CIE a* value, which will provide a theoretical basis for improving pork quality.

Effects of Extruded Corn with Different Gelatinization Degrees on Feed Preference, Growth Performance, Nutrient Digestibility, and Fecal Microbiota of Weaning Piglets.

Preference and performance trials were conducted to investigate the effects of extruded corn with different degrees of gelatinization on the feed preference, growth performance, nutrient digestibility, and fecal microbiota of weaning piglets. In the preference trial, 144 piglets who were 35 days old were weighed and allotted to six treatments with four replications per treatment. Piglets in each treatment group were allowed to choose two of the following four corn-supplemented diets: conventional corn (NC) or extruded corn with low (LEC; 41.82% gelatinization), medium (MEC; 62.60% gelatinization), or high (HEC; 89.93% gelatinization) degrees of gelatinization for 18 days. The results showed that the piglets preferred diets supplemented with a low degree of gelatinization of extruded corn. In the performance trial, 144 piglets who were 35 days old were weighed and allotted into four treatments with six replications per treatment. Piglets in each treatment were fed one of the four diets for 28 days. The results showed that LEC and MEC decreased the feed:gain ratio at 14-28 days and 0-28 days, respectively, and increased the apparent total tract digestibility (ATTD) of crude protein compared with NC. Meanwhile, LEC increased the total protein and globulin content in the plasma on day 14, and MEC increased the ATTD of ether extract (EE) compared with NC. Extruded corn with low and medium degrees of gelatinization increased the abundance of Bacteroidetes at the phylum level and Lactobacillus, Alloprevotella, Prevotellaceae_UCG-03, and Prevotella_2 at the genus level. The results showed that extruded corn can improve feed preference, increase growth performance and nutrient digestibility, and modify gut microbiota, and the ideal degree of gelatinization is approximately 41.82-62.60%.

Enhanced imaging of endogenous metabolites by negative ammonia assisted DESI/PI mass spectrometry.

In this work, endogenous metabolites in mouse brain tissue were imaged by negative desorption electrospray ionization (DESI), ammonia assisted DESI (aa-DESI), DESI/post-photoionization (DESI/PI), and ammonia assisted DESI/PI (aa-DESI/PI) mass spectrometry imaging (MSI) strategies. The combined effect of ammonia additive and post-photoionization was found to play an important role in the enhancement of sensitivity and coverage for endogenous analytes under ambient conditions. Compared with DESI, aa-DESI/PI can provide increased signal intensities for metabolites up to 37.1-fold, as well as the imaging of nine more small metabolites (m/z < 350) (26 for aa-DESI/PI and 17 for DESI) in mouse brain tissue. The results of Pearson correlation analysis and KEGG pathway analysis showed that the enhanced imaging strategy of aa-DESI/PI can facilitate the study of endogenous metabolic pathways and molecular networks. Moreover, the imaging results of mouse tumor tissue demonstrated the promising application of aa-DESI/PI in tumor research.

Enhanced Coverage and Sensitivity of Imprint DESI Mass Spectrometry Imaging for Plant Leaf Metabolites by Post-photoionization.

Plant metabolites exhibit a variety of different chemical properties, physiological activities, and biological functions. However, untargeted imaging of highly diverse metabolic profiles is still a great challenge. Here, metabolites in plant leaves were imaged via imprint, followed by desorption electrospray ionization/post-photoionization (imprint DESI/PI) mass spectrometry imaging. In contrast to the traditional imprint DESI method, quite a few metabolites, such as terpenoids, flavonoids, glycosides, alkylphenols, amino acids, phenolic acids, tannins, and lipids, in fresh sage leaves, ginkgo leaves, and tea leaves were well detected and imaged by imprint DESI/PI. More than 80 metabolites were additionally identified, and more than 1 order of magnitude higher signal intensities were obtained for most metabolites in the negative ion mode. By virtue of the significant improvement of coverage and sensitivity of PI, the catechin biosynthesis network in fresh tea leaves could be clearly illustrated, indicating the potential applicability of imprint DESI/PI in exploring the sites and pathways of plant metabolic conversion.

Effects of Growth Stage and Rearing Pattern on Pig Gut Microbiota.

Understanding the developmental period or the patterns of gut microbiota is important for nutritionists when designing a feed formula or adjusting a feeding strategy. The effects of growth stage or rearing pattern on pig gut microbiota have not been fully investigated. Herein, 39 fecal samples from pigs aged 3-9 months under two rearing patterns were collected to analyze the gut microbiome. Samples were clustered into three distinct groups, namely, early (3 months), middle (5 months), and late (7 and 9 months) stages, using principal coordinate analysis and analysis of similarities test. The rearing-pattern effects were very minimal, and no differences were observed in the alpha diversity [observed operational taxonomic units (OTUs) and Shannon index] of gut microbiota. From early and middle to late stage, Shannon index gradually decreased and OTUs gradually increased. Pigs at early stage were enriched with bacteria from family Prevotellaceae, including the genera Prevotella_9 and Prevotellaceae_NK3B31, whereas pigs at late stage were enriched with family Ruminococcaceae, including genera Ruminococcaceae_UCG-005 and Oscillospira. Pigs in the semi-free-grazing farm group were significantly enriched with bacteria from order Clostridiales. Growth stage better explained the changes in porcine gut microbiota than rearing patterns.

A Trajectory Tracking Control Based on a Terminal Sliding Mode for a Compliant Robot with Nonlinear Stiffness Joints.

A nonlinear stiffness actuator (NSA) can achieve high torque/force resolution in the low stiffness range and high bandwidth in the high stiffness range. However, for the NSA, due to the imperfect performance of the elastic mechanical component such as friction, hysteresis, and unmeasurable energy consumption caused by former factors, it is more difficult to achieve accurate position control compared to the rigid actuator. Moreover, for a compliant robot with multiple degree of freedoms (DOFs) driven by NSAs, the influence of every NSA on the trajectory of the end effector is different and even coupled. Therefore, it is a challenge to implement precise trajectory control on a robot driven by such NSAs. In this paper, a control algorithm based on the Terminal Sliding Mode (TSM) approach is proposed to control the end effector trajectory of the compliant robot with multiple DOFs driven by NSAs. This control algorithm reduces the coupling of the driving torque, and mitigates the influence of parametric variation. The closed-loop system's finite time convergence and stability are mathematically established via the Lyapunov stability theory. Moreover, under the same experimental conditions, by the comparison between the Proportion Differentiation (PD) controller and the controller using TSM method, the algorithm's efficacy is experimentally verified on the developed compliant robot. The results show that the trajectory tracking is more accurate for the controller using the TSM method compared to the PD controller.

A gentamicin-thioctic acid multifunctional hydrogel for accelerating infected wound healing.

Bacterial infections remain a major concern during wound healing and tissue bonding. The excessive proliferation of bacteria will seriously hinder the repair of the wound and even lead to death. Generally, surgical sutures might cause damage to the surrounding tissues and inevitable infection due to the unfixed shape of the wound. Thus, it is urgent to develop novel antibacterial skin dressing with self-healing and strong adhesion properties. Herein, we prepared an antibacterial and self-healable hydrogel with strong adhesion activity through natural small molecules, including thioctic acid TA and gentamicin (GM). The rapid ring-opening-polymerization of the TA (PTA) forms the backbone of macromolecules, and the functional hydrogel was constructed with the crosslinking of GM, termed as G-PTA, which offers hydrogen bonding interactions between the amino and hydroxyl groups of GM and carboxylic group side chains of poly(TA). The synthesized hydrogel exhibited rapid self-healing ability and strong tissue adhesion due to the internal dynamic disulfide bonds and multiple hydrogen bonds. Importantly, the introduction of GM enabled the G-PTA hydrogel to sustainably release antibiotics and exhibit a durative antibacterial effect with the degradation of PTA, which further shorten the therapeutic time and enhance tissue regeneration in a wound infection model. The in vitro and in vivo experiments demonstrate that the G-PTA hydrogel has potential as a surgical antibacterial biological adhesive, especially for bacterial wound infections.

Effects of dopants in the imaging of mouse brain by desorption electrospray ionization/post-photoionization mass spectrometry.

Desorption electrospray ionization/post-photoionization (DESI/PI) is a newly developed ionization method by the combination of DESI and post-photoionization for the simultaneous imaging of polar and nonpolar compounds in biological tissues. Dopants are of great importance in DESI/PI for the enhancement of signal intensities through ion-molecule reactions. In this work, to evaluate the performance of dopants in DESI/PI, an efficient homogenate model was developed, and four kinds of dopants (toluene, chlorobenzene, bromobenzene, and anisole) were tested using homogenate of mouse brain tissue as target sample. The influences of the dopants on the signal enhancements of different compounds were explained reasonably by the ionization mechanism. Then, the dopants with their optimum volume contents were applied to the mass spectrometry imaging (MSI). For a comprehensive imaging of various compounds with different polarities, methanol/toluene/formic acid (7:3:0.1) was chosen as the best choice. Finally, the stronger quantitative ability of DESI/PI with toluene as dopant for a few compounds in mouse brain tissue was demonstrated.

Other-Dehumanization Rather Than Self-Dehumanization Mediates the Relationship Between Violent Video Game Exposure and Aggressive Behavior.

Recent experimental studies demonstrated playing violent video games induced denying humanness to other people and suggested that other-dehumanization might account for the effect of violent video games on aggressive behavior. However, whether long-term violent video game exposure (VVGE) correlates with other-dehumanization has not been confirmed and the role of self-dehumanization in this effect is still controversial. Thus, this study attempted to provide correlational evidence and examined direct and indirect associations of VVGE and aggressive behavior through self- or other-dehumanization in 612 adolescents. We revealed other-dehumanization was linked with VVGE and it mediated the relationship between VVGE and aggressive behavior. In addition, we did not observe the predictive effect of VVGE for self-dehumanization. Our study suggested the short-term effect of playing a violent video game on other-dehumanization, observed in previous experimental investigations, could be extended to the long-term effect of VVGE. Perceiving others as less human, but not the players themselves, accounted for the effect of VVGE on aggressive behavior.

Recent Advances of Ambient Mass Spectrometry Imaging and Its Applications in Lipid and Metabolite Analysis.

Ambient mass spectrometry imaging (AMSI) has attracted much attention in recent years. As a kind of unlabeled molecular imaging technique, AMSI can enable in situ visualization of a large number of compounds in biological tissue sections in ambient conditions. In this review, the developments of various AMSI techniques are discussed according to one-step and two-step ionization strategies. In addition, recent applications of AMSI for lipid and metabolite analysis (from 2016 to 2021) in disease diagnosis, animal model research, plant science, drug metabolism and toxicology research, etc., are summarized. Finally, further perspectives of AMSI in spatial resolution, sensitivity, quantitative ability, convenience and software development are proposed.

FNDC5 expression closely correlates with muscle fiber types in porcine longissimus dorsi muscle and regulates myosin heavy chains (MyHCs) mRNA expression in C2C12 cells.

BACKGROUND: Irisin (a glycosylated protein) is cleaved from fibronectin type III domain-containing protein 5 (FNDC5), which is expressed mainly in animal muscle tissues and has multiple metabolic regulatory activities. However, their roles in controlling myofiber types in skeletal muscle remain unclear. METHODOLOGY: Two different commercial hybridized pigs, LJH (a crossed pig containing Chinese native pig genotypes) and DLY (Duroc × Landrace × Yorkshire) were selected to analyze FNDC5 mRNA expression and the mRNA composition of four adult myosin heavy chain (MyHC) isoforms (IIIaIIxIIb) in the longissimus dorsi (LD) muscle. C2C12 myoblasts were cultured to investigate the effects of FNDC5 on the four MyHCs mRNA expressive levels, using small interfering RNA for depletion and a eukaryotic expression vector carrying FNDC5 for overexpression. ZLN005 (a small molecule activator of FNDC5's upstream control gene PGC1α) or recombinant human irisin protein were also used. RESULTS: In LD muscle, LJH pigs had the higher FNDC5 mRNA level, and MyHC I or IIa proportion than DLY pigs (P <  0.05). For C2C12 cells in vitro, small interfering RNA (si-592) silencing of FNDC5 expression markedly reduced MyHC IIa mRNA levels (P <  0.05), while FNDC5 overexpression significantly increased MyHC IIa mRNA levels (P <  0.05). Exogenous irisin increased the mRNA levels of PGC1α (peroxisome proliferator-activated receptor gamma coactivator 1-alpha), FNDC5, MyHCI, MyHCIIa, NRF1 (nuclear respiratory factor 1), VEGF (vascular endothelial growth factor), and TFAM (mitochondrial transcription factor A,) (P <  0.05), and the enzyme activities of SDH (succinate dehydrogenase), CK (creatine kinase), and MDH (malate dehydrogenase) in C2C12 myotubes (P <  0.05). These results showed that FNDC5 mRNA expression had a significant association with the characteristics of myofiber types in porcine muscle, and participated in regulating MyHCs mRNA expression of C2C12 myogenic differentiation cells in vitro. FNDC5 could be an important factor to control muscle fiber types, which provides a new direction to investigate pork quality via muscle fiber characteristics.

Online Monitoring the Key Intermediates and Volatile Compounds Evolved from Green Tea Roasting by Synchrotron Radiation Photoionization Mass Spectrometry.

Online monitoring of the volatile compounds during the tea roasting process is crucial to find the optimum roasting conditions and improve the quality of green tea. In this work, synchrotron radiation photoionization mass spectrometry (SR-PIMS) was utilized to online monitor the evolved gaseous compounds during the tea roasting process. By virtue of "soft" ionization and fast data acquisition characteristics of SR-PIMS, dozens of aroma compounds including alcohols, aldehydes, furans, and nitrogen- and sulfur-containing species were detected and identified in real time. Moreover, 5-hydroxymethylfurfural (5-HMF), the key intermediate of Maillard reactions, was found with high sensitivity. Evolution processes of all the products could be observed via the time- and temperature-resolved profiles in N2 and the air. Dehydration was found to be the first step during roasting. Oxygen in the air was found to accelerate the formation rate of various stable species and intermediates in the course of the thermal treatment of fresh green tea. The formation mechanisms of evolved compounds such as three sulfur-containing compounds, i.e., dimethyl sulfide, hydrogen sulfide, and methanethiol, could be proposed according to the step-by-step formation process. The time-resolved results were demonstrated to be applicable in the evaluation of different roasting processes by statistical analysis. The optimum tea roasting temperature and duration are proposed to be around 200 °C and 1000 s.

Cholesterol was identified as a biomarker in human melanocytic nevi using DESI and DESI/PI mass spectrometry imaging.

The rapid differentiation between diseased tissue and healthy normal tissue is of great importance for the intraoperative diagnosis. Herein, desorption electrospray ionization (DESI) and DESI/post-photoionization (DESI/PI) mass spectrometry imaging were combined to in situ visualize the distribution of biochemicals within the tissue regions of human melanocytic nevi under the ambient condition with a spatial resolution of around 200 µm. Plenty of polar and nonpolar lipids were found to be specifically distributed in melanocytic nevi with statistical significance and could be used to differentiate the healthy normal tissue and melanocytic nevi. Cholesterol was further confirmed to be a potential biomarker for melanocytic nevi diagnosis by multivariate statistical analysis and immunohistochemistry of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and translocator protein (TSPO) enzymes. This work provides a visual way for the diagnosis of human melanocytic nevi by lipid profiling, which benefits the understanding of the pathological mechanism of melanocytic nevi and provides a new insight to control melanin growth from the synthesis, transport, and metabolism of cholesterol.

Simvastatin impairs hippocampal synaptic plasticity and cognitive function in mice.

Lipophilic statins which are blood brain barrier (BBB) permeable are speculated to affect the cholesterol synthesis and neural functions in the central nervous system. However, whether these statins can affect cholesterol levels and synaptic plasticity in hippocampus and the in vivo consequence remain unclear. Here, we report that long-term subcutaneous treatments of simvastatin significantly impair mouse hippocampal synaptic plasticity, reflected by the attenuated long-term potentiation of field excitatory postsynaptic potentials. The simvastatin administration causes a deficiency in recognition and spatial memory but fails to affect motor ability and anxiety behaviors in the mice. Mass spectrometry imaging indicates a significant decrease in cholesterol intensity in hippocampus of the mice receiving chronic simvastatin treatments. Such effects of simvastatin are transient because drug discontinuation can restore the hippocampal cholesterol level and synaptic plasticity and the memory function. These findings may provide further clues to elucidate the mechanisms of neurological side effects, especially the brain cognitive function impairment, caused by long-term usage of BBB-permeable statins.

Rearing pattern alters porcine myofiber type, fat deposition, associated microbial communities and functional capacity.

BACKGROUND: The Chinese believe that the meat of pigs reared in the past with free range tastes better than that of the pigs reared indoor on a large scale today. Gastrointestinal microflora is closely associated with the main factor of meat flavour, including fibre characteristics and lipid metabolism. Our method in this study involved different raising patterns within the semi free-grazing farm (FF) or indoor feeding farm (DF), the measurement of fat deposition and myofiber type by paraffin section and reverse transcription polymerase chain reaction and the identification of microbiome and functional capacities associated with meat quality through metagenomic sequencing. RESULTS: Results showed that the fat area in muscle and adipose tissue and the myofiber density significantly increased in the pigs of the FF group. The relative abundance of bacteria associated with lipid metabolism, such as g_Oscillibacter, in the feces of the FF group was higher than that in DF group, and the relative abundance of some bacteria with probiotic function, including g_Lactobacillus and g_Clostridium, was lower than that in DF group. The abundance of g_Clostridium was significantly positively correlated with the intramuscular fat area, whereas health-related bacteria, such as g_Butyricicoccus, g_Eubacterium, g_Phascolarctobacterium and g_Oribacterium, was significantly negatively correlated with abdominal fat area, myofiber density and adipose triglyceride lipase (ATGL) mRNA expression. KEGG analysis showed that pigs raised in semi free-grazing farm can activate the pathway of inosine monophosphate (IMP) biosynthesis, glycolysis/gluconeogenesis and alanine, aspartate and glutamate metabolism. CONCLUSIONS: Free range feeding improves meat quality by changing the fibre type, myofiber density and metabolic pathways related to flavour amino acids, IMP or glycolysis/gluconeogenesis in muscle. However, prolonged feeding cycle increases fat deposition and associated microbial communities.

Imaging of Polar and Nonpolar Species Using Compact Desorption Electrospray Ionization/Postphotoionization Mass Spectrometry.

Desorption electrospray ionization (DESI) mass spectrometry imaging (MSI) can simultaneously record the 2D distribution of polar biomolecules in tissue slices at ambient conditions. However, sensitivity of DESI-MSI for nonpolar compounds is restricted by low ionization efficiency and strong ion suppression. In this study, a compact postphotoionization assembly combined with DESI (DESI/PI) was developed for imaging polar and nonpolar molecules in tissue sections by switching off/on a portable krypton lamp. Compared with DESI, higher signal intensities of nonpolar compounds could be detected with DESI/PI. To further increase the ionization efficiency and transport of charged ions of DESI/PI, the desorption solvent composition and gas flow in the ionization tube were optimized. In mouse brain tissue, more than 2 orders of magnitude higher signal intensities for certain neutral biomolecules like creatine, cholesterol, and GalCer lipids were obtained by DESI/PI in the positive ion mode, compared with that of DESI. In the negative ion mode, ion yields of DESI/PI for glutamine and some lipids (HexCer, PE, and PE-O) were also increased by several-fold. Moreover, nonpolar constituents in plant tissue, such as catechins in leaf shoots of tea, could also be visualized by DESI/PI. Our results indicate that DESI/PI can expand the application field of DESI to nonpolar molecules, which is important for comprehensive imaging of biomolecules in biological tissues with moderate spatial resolution at ambient conditions.

Differential effects of clomipramine on depression-like behaviors induced by the chronic social defeat paradigm in tree shrews.

BACKGROUND: Anhedonia is a hallmark symptom in major depression that reflects deficits in hedonic capacity and it is also linked to motivation for reward. However, studies of the features of motivation in depressed tree shrews are rather sparse. AIMS: The study aimed to investigate the core feature of depression including lack of interest, motivation reduction, and social avoidance in tree shrews. Furthermore, the effects of the treatment using clomipramine on these depression-like behaviors were assessed. METHODS: The paradigm of chronic social defeat in tree shrews was used to evaluate the core feature of depression through examining their sucrose preference, break-point for reward, and social interaction. RESULTS: The results showed that social defeat lowered the curves of the sucrose preference and the break-point, as well as decreased social interaction. The results suggested that the subordinate animals exhibited interest loss, motivational reduction, and social avoidance. After oral treatment with clomipramine (50 mg/kg/day) for four weeks, most of the depression-like behaviors were reversed, whereas the motivational reduction was not clearly affected. Notably, the motivational reduction appeared obviously during the first week after the social defeat, and the conventional tricyclic antidepressant clomipramine did not reverse the reduced motivation. CONCLUSIONS: These findings imply that motivational variation might be applied as a more sensitive behavioral index in subordinate animals and could furthermore be used to evaluate potential agents as antidepressants.