The evolution of H5N1 influenza viruses in ducks in southern China

The pathogenicity of avian H5N1 influenza viruses to mammals has been evolving since the mid-1980s. Here, we demonstrate that H5N1 influenza viruses, isolated from apparently healthy domestic ducks in mainland China from 1999 through 2002, were becoming progressively more pathogenic for mammals, and we present a hypothesis explaining the mechanism of this evolutionary direction. Twenty-one viruses isolated from apparently healthy ducks in southern China from 1999 through 2002 were confirmed to be H5N1 subtype influenza A viruses. These isolates are antigenically similar to A/Goose/Guangdong/1/96 (H5N1) virus, which was the source of the 1997 Hong Kong "bird flu" hemagglutinin gene, and all are highly pathogenic in chickens. The viruses form four pathotypes on the basis of their replication and lethality in mice. There is a clear temporal pattern in the progressively increasing pathogenicity of these isolates in the mammalian model. Five of six H5N1 isolates tested replicated in inoculated ducks and were shed from trachea or cloaca, but none caused disease signs or death. Phylogenetic analysis of the full genome indicated that most of the viruses are reassortants containing the A/Goose/Guangdong/1/96-like hemagglutinin gene and the other genes from unknown Eurasian avian influenza viruses. This study is a characterization of the H5N1 avian influenza viruses recently circulating in ducks in mainland China. Our findings suggest that immediate action is needed to prevent the transmission of highly pathogenic avian influenza viruses from the apparently healthy ducks into chickens or mammalian hosts.

Effects of dietary lipids and Clostridium butyricum on fat deposition and meat quality of broiler chickens

The effects of dietary lipids and Clostridium butyricum on carcass quality, fat deposition, meat quality, and fatty acid contents of breast meat in broiler chickens were investigated. One hundred sixty one-day-old broiler chicks (Arbor Acres) were divided into 4 treatment groups in a 2x2 factorial arrangement and fed 4 diets with 2 lipid sources (soybean oil or fish oil) and 2 levels of C. butyricum (0 or 5 g/kg of diets) were used. Abdominal fat was significantly reduced when chicks were fed the fish oil diet compared with the soybean oil diet (P<0.01). Fish oil diets increased drip losses of the breast and thigh muscles, thawing losses of breast muscle, and boiling losses of thigh muscle (P<0.05). Moreover, the C. butyricum diet profoundly reduced shear force of muscle (P<0.05). The supplementation of C. butyricum increased i.m. fat, the contents of C20:5n-3 (P<0.05), and total n-3 polyunsaturated fatty acids (P<0.05) in breast muscle. Additionally, there were significant interactions between lipids and C. butyricum for drip losses of breast muscle (P<0.01) and boiling losses of thigh muscle (P<0.05) and for the contents of C20:5n-3 (P<0.05) and n-3 polyunsaturated fatty acids (P<0.05) of breast muscle. The results of this study indicate that dietary inclusion of C. butyricum improves meat quality and fatty acid profiles of breast meat in male broilers, particularly interacting with a fish oil diet.

The effect of glucagon-like peptide 2 injection on performance, small intestinal morphology, and nutrient transporter expression of stressed broiler chickens

An experiment was conducted to determine the effect of injecting glucagon-like peptide 2 (GLP-2) on the small intestinal weight, morphology, and nutrient transporter expression in pharmacologically stressed broiler chickens. A total of 144 seven-day-old birds were fed either a basal diet (CTRL) or a basal diet plus 30 mg of corticosterone (CORT)/kg of diet for a total of 14 d. Half of the birds from each group were injected daily with GLP-2 (6.7 nmol/kg of BW) or saline for 14 d. The average final BW, ADG, ADFI, and the ratio of feed intake to weight gain (F:G) was recorded over 21 d for the 4 groups of 36 birds, namely CTRL + saline, CTRL + GLP-2, CORT + saline, and CORT + GLP-2. In addition, the absolute and relative small intestinal weight, villus height (VH), and crypt depth (CD) of the duodenum and jejunum, as well as the abundance of sodium and glucose co-transporter 1 (SGLT-1), vitamin D-dependent calcium-binding protein-28,000 molecular weight (CaBP-D28k), and peptide transporter 1 (PepT-1) mRNA in the duodenum and of liver fatty acid-binding protein (L-FABP) mRNA in the jejunum. The total DNA, RNA, and protein content in small intestinal mucosa were also determined. The results showed that CORT administration significantly lowered average final BW, ADG, ADFI, absolute small intestinal weight, VH, and CD of duodenum and jejunum (P < 0.05) while increasing the relative small intestinal weight, F:G, relative abundance of SGLT-1, CaBP-D28k, PepT-1, and L-FABP mRNA (P < 0.05). Glucagon-like peptide 2 injection increased the average final BW, ADG, VH, and CD in duodenum and jejunum and relative abundance of SGLT-1, CaBP-28k, PepT1, and PepT1 mRNA of broiler chickens, respectively (P < 0.05), and decreased F:G (P < 0.05). In chickens fed basal diet plus CORT, injecting GLP-2 decreased F:G (P < 0.05); increased VH and CD of duodenum and CD of jejunum; and increased relative abundance of SGLT-1, CaBP-D28k, PepT-1, and L-FABP mRNA, RNA, and total protein content in small intestine compared with the injection of saline (P < 0.05). In birds fed the basal diet, GLP-2 injection decreased F:G (P < 0.05) and increased final BW, ADG, small bowel weight, CD of jejunum, and relative abundance of CaBP-D28k and PepT-1 mRNA compared with injecting saline (P < 0.05). In conclusion, GLP-2 injection reversed the negative effect of stress on the weight and morphology and the absorptive function of small bowel of broiler chickens. Glucagon-like peptide 2 injection also had a positive effect on the growth performance of healthy broiler chickens.

Effects and mechanisms of H(2)O(2) on production of dicarboxylic acid

The system of producing long chain dicarboxylic acid (DCA) by Candida tropicalis is an aerobic and viscous fermentation system. A method to overcome the gas-liquid transport resistance and to increase oxygen supply is by adding hydrogen peroxide (H(2)O(2)) to the fermentation system. Here we report that the H(2)O(2) not only can enhance the oxygen supply but also change the metabolism by inducing cytochrome P450, the key enzyme of a, o-oxidation. When C. tropicalis was cultivated in a 3-L bioreactor using the combination of aeration and H(2)O(2) feeding, DCA production rates increased by about 10% after a short period of decrease at the beginning. Furthermore, the experiments showed that the maximum activities of P450 could be induced at 2 mM H(2)O(2), and the inducible mechanisms are also discussed. Moreover, we suggest that alkane might be oxidized through the "peroxide shunt pathway" when H(2)O(2) is present. By adding H(2)O(2), the DCA yield in a 22-L bioreactor could increase by 25.3% and reach 153.9 g/L.

Relationship between body composition, insulin resistance, and hormonal profiles in women with polycystic ovary syndrome

OBJECTIVE

To investigate how body fat influences glucose metabolism and hormone profiles in women with polycystic ovary syndrome (PCOS), compared to women without PCOS.

METHODS

We conducted a cross-sectional study of 166 women with PCOS and 139 age-matched control women at Peking University Third Hospital (Beijing, China) from March 2016 to December 2021. All participants underwent bioimpedance rate assessment of clinical, anthropometric, hormonal, and metabolic features. In particular, body composition parameters were assessed, based on the methods used in a previous study. Homeostasis model assessment-insulin resistance (HOMA-IR) and other indices calculated from fasting glucose and insulin were used to measure insulin resistance. The hormonal profiles [follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E2), prolactin (PRL), total testosterone (T), and androstenedione (A2)] were assessed by using biochemical methods. Two subgroup analyses were conducted according to waist-to-hip ratio (WHR; < 0.85, non-central obesity and ≥ 0.85, central obesity) and body fat percentage (BFP; < 35% for lean and ≥35% for obesity). The indices above were analyzed using a two-sided t-test or Wilcoxon rank sum test. Linear regression was used to investigate the effects of body composition on metabolism and sex hormones in the PCOS and control groups.

RESULTS

Compared to women without PCOS, women with PCOS and central obesity (P=0.021), PCOS and noncentral obesity (P<0.001), PCOS and high BFP (P<0.001), and PCOS and low BFP (P<0.001) had more severe glucose metabolism evaluated with HOMA-IR. Women with PCOS experienced greater insulin sensitivity impairment than did the normal population for every equal increase in BFP. LH, LH/FSH, total testosterone, and androstenedione were significantly higher in patients with PCOS than in healthy controls, regardless of WHR and BFP stratification. However, negative correlations existed between body fat indices (i.e., BFP and body mass index) and hormone indices (i.e., LH and androstenedione) in the PCOS group, but were absent in the control group.

CONCLUSIONS

Obese and non-obese women with PCOS have more severe insulin resistance and sex-hormone disorders than women without PCOS. The effect of body fat on sex-hormone disorders is only exist in women with PCOS. These findings suggested that PCOS clinical guidelines should be more specific to body fat.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/, Registration No. NCT04264832.

Electron impact mass spectral fragmentation of 2a,4-disubstituted 2-chloro/2,2-dichloro-2,2a,3,4-tetrahydro-1H-azeto[2,1-d][1,5]benzothia zepin-1-ones

The mass spectrometric behaviour of nine 2a,4-disubstituted 2-chloro/2,2-dichloro-2,2a,3,4-tetrahydro-1H-azeto[2,1-d][1,5]b enzothiazepin-1-ones has been studied with the aid of mass-analysed ion kinetic energy spectrometry and accurate mass measurements under electron impact ionization. All compounds show a tendency to eliminate a neutral chlorine atom, or a chloroketene, or neutral propene, or styrene or substituted styrene molecule, plus Cl and/or H (or Cl) atom(s), to yield [M-Cl]+ ions, 2,3-dihydro-1,5-benzothiazepine derivative ions, 4,5-dihydro-5H-1,5-benzothiazepin-4-one ions which can further lose CO to give 1,4-benzothiazine ions. Both molecular ions and [M-Cl]+ ions show a tendency to eliminate an ethyl or benzyl/substituted benzyl radical to produce 2,2a-dihydro-1H-azeto[2,1-c][1,4]benzothiazin-1-one ions. The [M-Cl]+ ions could undergo rearrangement to yield 2,2a-dihydro-1H-azeto[2,1-d][1,5]benzothiazepin-1-one ions, 2,2a,3,4-tetrahydro-1H-azeto[1,2-a]quinoline ions or 1,1a,2,3-tetrahydro-azirino[2,1-d][1,5]benzothiazepine ions by loss of an ethane or a benzene/substituted benzene, a SH radical or a CO molecule. The molecular ions could also undergo rearrangement reactions to form other small fragment ions.

An Organic-Inorganic Hybrid Pyrrolidinium Ferroelectric Based on Solvent Selective Effect

Organic-inorganic hybrid ferroelectrics (OIHFs) have fueled enormous interest benefiting from their less environmental pollution, performance-tailored functionality, low product costs as well as tunability of structures. However, the lack of material synthesis approaches and diverse targeted molecular design is a stumbling block for designing novel OIHFs rationally. Here, we report a unique organic-inorganic hybrid ferroelectric (3,3-difluoropyrrolidine)₂CdCl₄ 1 and another novel nonferroelectric crystal (3,3-difluoropyrrolidine)₂Cd₂Cl₆ 2 by changing various crystallization solvents. Significantly, 1 presents a ferroelectric phase transition behavior at ∼367 K, and the distinct symmetry breaking, i.e., mmmFm, sets up a biaxial ferroelectric with four equivalent directions of polarization, which has a P_r ∼ 0.77 μC/cm². Systematic studies prove that ferroelectricity can be ascribed to the synergistic effects of the distortion of the inorganic anion skeleton and the ordering of organic cations. This work reveals the potential of constructing novel ferroelectrics based on the solvent selective effect and pyrrolidinium as organic cations.

Tunable and parabolic piezoelectricity in hafnia under epitaxial strain

Piezoelectrics are a class of functional materials that have been extensively used for application in modern electro-mechanical and mechatronics technologies. The sign of longitudinal piezoelectric coefficients is typically positive but recently a few ferroelectrics, such as ferroelectric polymer poly(vinylidene fluoride) and van der Waals ferroelectric CuInP2S6, were experimentally found to have negative piezoelectricity. Here, using first-principles calculation and measurements, we show that the sign of the longitudinal linear piezoelectric coefficient of HfO2 can be tuned from positive to negative via epitaxial strain. Nonlinear and even parabolic piezoelectric behaviors are further found at tensile epitaxial strain. This parabolic piezoelectric behavior implies that the polarization decreases when increasing the magnitude of either compressive or tensile longitudinal strain, or, equivalently, that the strain increases when increasing the magnitude of electric field being either parallel or antiparallel to the direction of polarization. The unusual piezoelectric effects are from the chemical coordination of the active oxygen atoms. These striking piezoelectric features of positive and negative sign, as well as linear and parabolical behaviors, expand the current knowledge in piezoelectricity and broaden the potential of piezoelectric applications towards electro-mechanical and communications technology.

Electron impact mass spectral fragmentation patterns of 2a,4-disubstituted 5-benzoyl-2-chloro-2a,3,4,5-tetrahydroazeto[1,2-a][1,5]benzodiazepin-1( 2H)-ones

The mass spectrometric behaviour of six 2a,4-disubstituted 5-benzoyl-2-chloro-2a,3,4,5-tetrahydroazeto[1,2-a][1,5]benzodia zepin-1(2H)-ones has been studied with the aid of mass-analysed ion kinetic energy spectrometry and accurate mass measurements under electron impact ionization. All compounds show a tendency to eliminate a chlorine atom, a chlorine atom plus benzaldehyde, benzoyl radical, chloroketene or chlorine atom plus CO and H2O molecules to yield, respectively, [M-Cl]+ ions, 2a,4-disubstituted 2a,3-dihydroazeto[1,2-a][1,5]benzodiazepin-1(2H)-one ions, [M-PhCO]+ ions, 2,4-disubstituted 1-benzoyl-2,3-dihydro-1H-1,5-benzodiazepine ions, or 1,2,4-trisubstituted 1H-1,7-benzodiazonine ions, which could also be formed from [M-Cl]+ ions by loss of CO and H2O molecules simultaneously. The [M-Cl]+ ions could further lose benzoyl radical to form [M-Cl-PhCO]+ ions, or lose benzoyl amide and undergo a rearrangement to form 4,6-disubstituted 1-benzoazocine-2(1H)-one ions. The [M-PhCO]+ ions could eliminate NH to produce 2a,4-disubstituted 2,2a,3,4-tetrahydroazeto[1,2,-a]quinolin-1-one ions, which could further eliminate chloroketene, CO and/or HCl to produce some important ions, respectively. 2,4-Disubstituted 1-benzoyl-2,3-dihydro-1H-1,5-benzodiazepine ions could lose benzoyl radical to yield 2,4-disubstituted 2,3-dihydro-1H-1,5-benzodiazepine ions, which could further yield other small fragment ions by loss of propene/styrene or small fragments.

[Study on fermentation of long-chain dicarboxylic acid based on enzymology]

In this paper, we studied the effects of the adding time of alkane on the expression of P450 and production of dicarboxylic acid. A novel fermentation process, in which no or a little alkane was added to make the cells growing more quickly during the growth stage, followed by the addition of alkane to induce cytochromes P450 for 6-8 hours, was established. The results showed that the new process was much better than the old process on inductivities of cytochromes P450 and production of dicarboxylic acid. The new process improved nearly 14.56% expression of P450 and 14.15% production of dicarboxylic acid.

Effect of artemether on hexokinase, glucose phosphate isomerase and phosphofructokinase of Schistosoma japonicum harbored in mice

AIM

To study the effect of artemether (Art) on hexokinase (HK), glucose phosphate isomerase (GPI) and phosphofructokinase (PFK) of Schistosoma japonicum.

METHODS

Mice infected with schistosome cercariae for 4-5 wk were treated ig with Art 100 or 300 mg.kg-1 and killed 24 h or 48 h after medication for collection of schistosomes. The activities of HK, GPI and PFK of the worms were determined by measuring the formation of NADPH or consumption of NADH.

RESULTS

Worms from the infected mice treated ig with Art at a single dose of 300 mg.kg-1 the inhibition rates of HK activity of female and male worms were 33.7% and 13.7%, respectively 24 h after administration. Similar results were seen in GPI activity, but 48 h after medication, the inhibition rate of GPI increased to 46.2% (female) and 32.9% (male), respectively. Worms from mice treated with Art 100 or 300 mg.kg-1, the inhibitory effect on PFK in female worms was found much higher than that of male worms the inhibition rates of PFK were 64.9%-71.0% in female worms and 16.3%-54.2% in male worms, respectively at 24 h and 48 h after treatment.

CONCLUSION

The results suggest that in the glycolytic pathway of schistosome PFK might be one of the targets attacked by Art.

[Study on the plasmid instability of Bdellovibrio BDG-9]

A new method system was established in this paper to study the plasmid in stability of Bdellovibrio BDG-9. Using this system, it was found that when BDG-9 was cultured singly on the SMB plate, plasmid pST I was unstable although pST I still replicated and distributed to progeny cell normally. The results showed that the pST I copy number in single cell of BDG-9 decreased gradually to zero with the propagation of BDG-9. Additionally, plasmid pST I was very important for the growth of BDG-9, and with the lacking of pST I s, the growth and propagation of BDG-9 ceased.

Ferroelectric tunnel junctions integrated on semiconductors with enhanced fatigue resistance

Oxide-based ferroelectric tunnel junctions (FTJs) show promise for nonvolatile memory and neuromorphic applications, making their integration with existing semiconductor technologies highly desirable. Furthermore, resistance fatigue in current silicon-based integration remains a critical issue. Understanding this fatigue mechanism in semiconductor-integrated FTJ is essential yet unresolved. Here, we systematically investigate the fatigue performance of ultrathin bismuth ferrite BiFeO3 (BFO)-based FTJs integrated with various semiconductors. Notably, the BFO/gallium arsenide FTJ exhibits superior fatigue resistance characteristics (>108 cycles), surpassing the BFO/silicon FTJ (>106 cycles) and even approaching epitaxial oxide FTJs (>109 cycles). The atomic-scale fatigue mechanism is revealed as lattice structure collapse caused by oxygen vacancy accumulation in BFO near semiconductors after repeated switching. The enhanced fatigue-resistant behavior in BFO/gallium arsenide FTJ is due to gallium arsenide's weak oxygen affinity, resulting in fewer oxygen vacancies. These findings provide deeper insights into the atomic-scale fatigue mechanism of semiconductor-integrated FTJs and pave the way for fabricating fatigue-resistant oxide FTJs for practical applications.

Obesity is associated with lower levels of negative emotions in polycystic ovary syndrome in clinical and animal studies

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most common endocrine and metabolic disorders in women of reproductive age. It is frequently comorbid with obesity and negative emotions. Currently, there are few reports on the relationship between obesity and negative emotions in patients with PCOS. Here we performed both basic and clinical studies to study the relationship between obesity and negative emotions in PCOS.

METHODS

We performed a cross-sectional study including 608 patients with PCOS and 184 healthy participants to assess the mental health status of people with different body mass indices (BMI). Self-rated anxiety, depression, and perceived stress scales were used for subjective mood evaluations. Rat PCOS models fed 45 and 60% high-fat diets were used to confirm the results of the clinical study. Elevated plus maze and open field tests were used to assess anxiety- and depression-like behaviors in rats.

RESULTS

We observed overweight/obesity, increased depression, anxiety, and perceived stress in women with PCOS, and found that anxiety and depression were negatively correlated with BMI in patients with severe obesity and PCOS. Similar results were confirmed in the animal study; the elevated plus maze test and open field test demonstrated that only 60% of high fat diet-induced obesity partly reversed anxiety- and depression-like behaviors in PCOS rats. A high-fat diet also modulated rat hypothalamic and hippocampal luteinizing hormone and testosterone levels.

CONCLUSION

These results reveal a potential relationship between obesity and negative emotions in PCOS and prompt further investigation. The interactions between various symptoms of PCOS may be targeted to improve the overall well-being of patients.

Dominant activities of fear engram cells in the dorsal dentate gyrus underlie fear generalization in mice

Over-generalized fear is a maladaptive response to harmless stimuli or situations characteristic of posttraumatic stress disorder (PTSD) and other anxiety disorders. The dorsal dentate gyrus (dDG) contains engram cells that play a crucial role in accurate memory retrieval. However, the coordination mechanism of neuronal subpopulations within the dDG network during fear generalization is not well understood. Here, with the Tet-off system combined with immunostaining and two-photon calcium imaging, we report that dDG fear engram cells labeled in the conditioned context constitutes a significantly higher proportion of dDG neurons activated in a similar context where mice show generalized fear. The activation of these dDG fear engram cells encoding the conditioned context is both sufficient and necessary for inducing fear generalization in the similar context. Activities of mossy cells in the ventral dentate gyrus (vMCs) are significantly suppressed in mice showing fear generalization in a similar context, and activating the vMCs-dDG pathway suppresses generalized but not conditioned fear. Finally, modifying fear memory engrams in the dDG with "safety" signals effectively rescues fear generalization. These findings reveal that the competitive advantage of dDG engram cells underlies fear generalization, which can be rescued by activating the vMCs-dDG pathway or modifying fear memory engrams, and provide novel insights into the dDG network as the neuronal basis of fear generalization.

A brainstem circuit amplifies aversion

Dynamic gain control of aversive signals enables adaptive behavioral responses. Although the role of amygdalar circuits in aversive processing is well established, the neural pathway for amplifying aversion remains elusive. Here, we show that the brainstem circuit linking the interpeduncular nucleus (IPN) with the nucleus incertus (NI) amplifies aversion and promotes avoidant behaviors. IPN GABA neurons are activated by aversive stimuli and their predicting cues, with their response intensity closely tracking aversive values. Activating these neurons does not trigger aversive behavior on its own but rather amplifies responses to aversive stimuli, whereas their ablation or inhibition suppresses such responses. Detailed circuit dissection revealed anatomically distinct subgroups within the IPN GABA neuron population, highlighting the NI-projecting subgroup as the modulator of aversiveness related to fear and opioid withdrawal. These findings unveil the IPN-NI circuit as an aversion amplifier and suggest potential targets for interventions against affective disorders and opioid relapse.

[Study on the cytochrome P450 activity in alkane converting process of Candida tropicalis]

A method of reduced CO-difference spectrum was established to study the cytochrome P450 activity of the whole cell of Candida tropicalis during the alkane converting process. Using this method, the cytochrome P450 activities of the whole cells that were cultured in the different concentrations of alkane were studied. The results showed that the 5% alkane could induce the cytochrome P450 activity obviously but not inhibit the growth of cells, so it was determined preliminarily that the alkane concentration of the seed medium was 5%. The cytochrome P450 activities of dicarboxylic acid (DCA) fermentation processing were further studied. During the exponential phase of growth, the cytochrome P450 activity increased smoothly. However, during the phase of production of dicarboxylic acid, the cytochrome P450 activities increased rapidly after a sort decrease. The results still showed that the rate of production of dicarboxylic acid increased with the cytochrome P450 activity.