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Understanding the ecophysiological and nutrient-use strategies of dominant species is important for clarifying plant growth and an ecological process in their community under unbalanced N and P inputs. This study investigated effects of N and P addition [main plot: 0, 25, 50, and 100 kg(N) ha-1 year-1; subplot: 0, 20, 40, and 80 kg(P) ha-1 year-1] on leaf N and P contents (LNCa and LPCa), photosynthetic capacity (PNmax) and photosynthetic N- and P-use efficiencies (PNUE and PPUE) in three species (Stipa bungeana, Bothriochloa ischaemum, and Lespedeza davurica) in a semiarid grassland in China. At the assessing time, N addition alone significantly increased LNCa and LNCa/LPCa ratio of Stipa bungeana (C3 grass) only, while PNmax increased significantly in all three species. Under N addition, P addition caused significantly lower LNCa, but higher PNUE and PNmax in Bothriochloa ischaemum (C4 grass) and Stipa bungeana. The LNCa, PNmax, and PNUE of Lespedeza davurica (C3 legume) increased significantly after P addition regardless of N application. The LNCa/LPCa for optimum PNUE changed with species. The PNmax and PNUE of Bothriochloa ischaemum and Stipa bungeana had a peak when LNCa/LPCa attained ~ 11 and ~ 20. Lespedeza davurica tended to retain greater PNmax and PNUE at lower LNCa/LPCa. Our results indicated that the C3 grass was more sensitive to N and P addition than the C4 grass and the C3 legume in terms of leaf N and P contents and PNmax. Such interspecific variations of nutrient use in response to N and/or P addition are favorable for maintaining the diversity and the stability of the grassland community. [ABSTRACT FROM AUTHOR]

We examine a simple model of the liquid state of an electrorheological fluid, with emphasis on the role of many-particle (local-field) effects. The induced dipole moments are treated as internal degrees of freedom. The distribution function for these dipole moments is calculated self-consistently within the mean-spherical approximation (MSA). The present MSA formalism is more rigorous and slightly more general than the ‘‘mean-field’’ treatment by Adriani and Gast [Phys. Fluids 31, 2757 (1988)]. We also use a more accurate MSA correlation function which leads to numerical results suggestive of a phase transition out of the liquid state at a critical value of the dimensionless dipole interaction strength. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the expression of kir6.2 subunit of the sarcKATP channel in exercise-induced myocardial injury and to elucidate the underlying mechanism of myocardial protection by sarcKATP channels. MATERIALS AND METHODS: Healthy male Sprague Dawley(SD) rats were divided into the Control (C) and the Exhaustive Exercise (EE) group. The one-time exhaustive exercise-induced myocardial injury model was established on a treadmill at a speed of 35 m/min. Alterations in myocardial ischemia and hypoxia were examined by hematoxylin-basic fuchsin-picric acid (HBFP) staining and the concentration of cardiac Troponin I (cTnl), a sensitive and specific marker for myocardial injury, was detected using immunochemiluminescence analysis. The mRNA expression level, localization, and protein expression of sarcKATP channel subunit kir6.2 were determined by quantitative reverse transcriptase- polymerase chain reaction (qRT-PCR), immunofluorescence, and Western blot analysis, respectively. RESULTS: When compared to Group C, rats in Group EE demonstrated significantly increased areas of myocardial ischemia and hypoxia. Moreover, increased serum levels of cTnI were detected. Increased kir6.2 expression was found on the surface of cardiomyocytes and kir6.2 protein expression was also significantly increased. CONCLUSIONS: Exercise-induced myocardial injury did not result in noticeable alterations in kir6.2 mRNA expression. However, kir6.2 protein expression was significantly increased and resulted in increased numbers of sarcKATP channel openings in the myocardium, thereby further inhibiting exercise-induced myocardial injury. [ABSTRACT FROM AUTHOR]

Bothriochloa ischaemum L. is an important species in many temperate regions, but information about the interactive effects of water stress and fertilization on its photosynthetic characteristics was inadequate. A pot experiment was conducted to investigate the effects of three water [80% (HW), 40% (MW), and 20% (LW) of field capacity (FC)] and four fertilization regimes [nitrogen (N), phosphorus (P), nitrogen with phosphorus (NP), and no fertilization] on leaf photosynthesis. Leaf gas exchange and photosynthetic light-response curves were measured at the flowering phase of B. ischaemum. Water stress decreased not only the leaf gas-exchange parameters, such as net photosynthetic rate ( PN), stomatal conductance ( gs), transpiration rate ( E), and water-use efficiency (WUE) of B. ischaemum, but also downregulated PN-photosynthetically active radiation (PAR) curve parameters, such as light-saturated net photosynthetic rate ( PNmax), apparent quantum efficiency (AQE), and light compensation point (LCP). Fertilization (N, P, and NP) enhanced the daily mean PN values and PNmax under the HW regime. Addition of N (either alone or with P) improved the photosynthetic capacity of B. ischaemum under the MW and LW regimes by increasing PN, PNmax, and AQE and reducing dark respiration rate and LCP, but the addition of P alone did not significantly improve the photosynthetic performance. Decline in PN under each fertilization regime occurred during the day and it was caused mainly by nonstomatal limitation. Our results indicated that water was the primary limiting factor for photosynthesis in B. ischaemum, and that appropriate levels of N fertilization improved its potential photosynthetic capacity under water-deficit conditions. [ABSTRACT FROM AUTHOR]

Perennial forage legumes, particularly lucerne ( Medicago sativa L.), play a significant role in crop/livestock mixed farming systems in the semiarid region of the Loess Plateau of China as stock feed and a source of nitrogen for subsequent crops. However, there is evidence that lucerne reduces soil water deep in the soil profile, thereby reducing subsequent crop productivity. From 2004 to 2010, this study evaluated the forage productivity and water use of two locally adapted perennial legume species, milk vetch ( Astragalus adsurgens Pall.) and bush clover ( Lespedeza davurica S.), compared with lucerne. The 7-year total and average annual forage yield of milk vetch were 56 and 8 t ha−1 and bush clover was 42 and 6 t ha−1, respectively, significantly lower than lucerne at 91 and 13 t ha−1. However, despite lower water-use efficiencies (16 and 12 kg ha−1 mm−1 for milk vetch and bush clover, respectively, compared to 22 kg ha−1 mm−1 for lucerne), the total 7-year water use in milk vetch and bush clover was 3500 mm and 3490 mm, respectively, which was 135-140 mm less than lucerne. After 7 years, lucerne had extracted water from the upper 5 m soil, whereas bush clover used water mainly from the upper 2 m of the soil profile and milk vetch still had some water available below 3 m. We conclude that while the locally adapted forage legumes were not as productive as lucerne as a source of fodder in mixed cropping/livestock system in this region, they use less water, which may be advantageous in drier regions. [ABSTRACT FROM AUTHOR]

Poly(ℇ-caprolactone) was characterized by size exclusion chromatography on-line with a right-angle laser-light scattering photometer and a four-capillary bridge design differential viscometer (SEC/RI/RALLS/DV) in tetrahydrofuran (THF) at 25°C. The dependence of intrinsic viscosity and radius of gyration of poly(ℇ-caprolactone) on molecular weight was established, and Flory's characteristic ratio C ∞ was calculated for this polymer from these data. The results show that THF is a good solvent for poly(ℇ-caprolactone). Poly(ℇ-caprolactone) exhibits a random-coil conformation in THF, and SEC with online RALLS and DV detectors offer an easy way to obtain information on chain flexibility. The C ∞ results are in good accord with previously reported values for this polymer. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of shackling and wing flapping on stress, postmortem metabolism, AMP-activated protein kinase (AMPK), and quality of broiler pectoralis major. Before slaughter, a total of 80 Arbor Acres broilers was randomly categorized into 2 replicate pens (40 broilers per pen) and each pen randomly divided into 2 groups (shackling, T; control, C). Corticosterone, creatine kinase, and lactate dehydrogenase were determined on blood plasma parameters. Pectoralis major were removed after evisceration and used for determination of energy metabolism, meat quality, and AMPK phosphorylation. In this study, shackling and wing flapping increased (P  < 0.05) plasma corticosterone level, creatine kinase activity, and lactate dehydrogenase activity. Shackling and wing flapping increased (P  < 0.05) AMPKα(Thr172) and acetyl-CoA carboxylase (ACC) phosphorylation, followed by rapid glycolysis and accumulation of lactic acid, and leading to a fast pH decline in the initial postmortem meat. Shackling and wing flapping have an adverse effect on final meat quality, which increased (P  < 0.05) muscle lightness, drip loss, and cooking loss. The results indicate that antemortem shackling and wing flapping increased stress and AMPKα(Thr172) phosphorylation, which may accelerate glycolysis and lead to a low water-holding capacity of broiler meat. [ABSTRACT FROM AUTHOR]

Cardiac endothelial cells (ECs) are important targets for cardiovascular gene therapy. However, the approach of stably transducing ECs in vivo using different vectors, including adeno-associated virus (AAV), remains unexamined. Regarding this unmet need, two AAV libraries from DNA shuffling and random peptide display were simultaneously screened in a transgenic mouse model. Cardiac ECs were isolated by cell sorting for salvage of EC-targeting AAV. Two AAV variants, i.e., EC71 and EC73, enriched in cardiac EC, were further characterized for their tissue tropism. Both of them demonstrated remarkably enhanced transduction of cardiac ECs and reduced infection of liver ECs in comparison to natural AAVs after intravenous injection. Significantly, persistent transgene expression was maintained in mouse cardiac ECs in vivo for at least 4 months. The EC71 vector was selected for delivery of the endothelial nitric oxide synthase (eNOS) gene into cardiac ECs in a mouse model of myocardial infarction. Enhanced eNOS activity was observed in the mouse heart and lung, which was correlated with partially improved cardiac function. Taken together, two AAV capsids were evolved with more efficient transduction in cardiovascular endothelium in vivo , but their endothelial tropism might need to be further optimized for practical application to cardiac gene therapy., Competing Interests: The authors declare no competing interests., (© 2021 The Author(s).)

Developing alternatives to antibiotics is an urgent need in livestock production. Antimicrobial peptides (AMPs) are regarded as powerful antibiotic substitutes (ASs) because AMPs have broad-spectrum antimicrobial activities and growth-promoting ability. Here, we aimed to comprehensively assess the effects of AMPs on the growth performance, diarrhea rate, intestinal morphology and immunity of healthy or challenged piglets, compared with an antibiotics group or negative control group. We performed a set of meta-analyses of feeding trials from database inception to 27 May 2019. Among the 1379 identified studies, 20 were included in our meta-analyses (56 arms and 4067 piglets). The meta-analyses revealed that (1) compared with the negative control group, AMPs significantly improved the healthy piglets' average daily gain (ADG), average daily feed intake (ADFI), gain : feed ratio (G/F), levels of immune globulin (Ig) IgM and IgG, and intestinal villus height : crypt depth ratio (V/C) (P < 0.05). Meanwhile, AMPs significantly increased the challenged piglets' ADG, ADFI, G/F and V/C of the jejunum and ileum, and notably deceased the diarrhea rate (P < 0.05); (2) compared with antibiotics group, the effects of AMPs were slightly weaker than those of antibiotics in the healthy piglets, but AMPs have similar effects to those of antibiotics in challenged piglets. In a higher purity, the optimal dose of AMPs may be approximately 0.01%. Our findings indicate that AMPs can improve piglet growth performance, enhance immunity, benefit intestinal morphology and decrease the diarrheal rate. AMPs could be great ASs especially under infection conditions.

The effectiveness of Lactobacillus sakei B-2 inoculated as a protective culture on the inhibition of spoilage bacteria on sliced vacuum packed cooked ham was investigated by using culture-dependent and -independent approaches. Total microbial DNA was directly extracted from both control and treatment samples, and subjected to a nested PCR protocol, PCR-DGGE analysis was used to identify and monitor the dynamic changes in the microbial population, followed by partial 16S rDNA sequencing. The DGGE profile demonstrated that the protective culture effectively suppressed growth of predominant spoilage bacteria L. sakei, Lactobacillus curvatus and Leuconostoc mesenteroides in cooked ham during storage at 4°C, however, growth of uncultured Leuconostoc was not inhibited. The shelf-life of this product inoculated with L. sakei B-2, at levels of 5.91±0.04log(10)CFUg(-1) was 35 days, compared to 15 days of control samples, when the ham was stored at 4°C.

Laron syndrome [growth hormone (GH) insensitivity syndrome] is a hereditary dwarfism resulting from defects in the GH receptor (GHR) gene. GHR deficiency has not been reported in mammals other than humans. Many aspects of GHR dysfunction remain unknown because of ethical and practical limitations in studying humans. To create a mammalian model for this disease, we generated mice bearing a disrupted GHR/binding protein (GHR/BP) gene through a homologous gene targeting approach. Homozygous GHR/BP knockout mice showed severe postnatal growth retardation, proportionate dwarfism, absence of the GHR and GH binding protein, greatly decreased serum insulin-like growth factor I and elevated serum GH concentrations. These characteristics represent the phenotype typical of individuals with Laron syndrome. Animals heterozygous for the GHR/BP defect show only minimal growth impairment but have an intermediate biochemical phenotype, with decreased GHR and GH binding protein expression and slightly diminished insulin-like growth factor I levels. These findings indicate that the GHR/BP-deficient mouse (Laron mouse) is a suitable model for human Laron syndrome that will prove useful for the elucidation of many aspects of GHR/BP function that cannot be obtained in humans.

Specific serine and threonine residues of recombinant human beta-casein produced in Escherichia coli were shown to be phosphorylated in vivo when human casein kinase II was coexpressed in the same plasmid. All of the phosphorylated forms found in the native protein were also detected in the recombinant protein. The phosphorylation of recombinant human beta-casein was confirmed by immunoblots, fast protein liquid chromatography, urea-polyacrylamide gel electrophoresis, SDS-polyacrylamide gel electrophoresis, and liquid chromatography-mass spectrometry. The results indicate that the substrate specificity of casein kinase II in vivo was unaffected in its recombinant form. This is the first demonstration of in vivo phosphorylation of specific residues of a multiphosphorylated protein produced in E. coli with a single plasmid.

Following the growth hormone (GH) and GH receptor (R) interaction, the receptor and Janus tyrosine kinase 2 (JAK2) become tyrosine phosphorylated along with other intracellular proteins. Previously, we reported that GH induces tyrosine phosphorylation of intracellular proteins with molecular masses of approx 95 kDa (pp95) in mouse 3T3-F442A preadipocytes and in mouse L-cells that express recombinant GHRs. We have studied this GH-induced phosphorylation event in greater detail. Three proteins with apparent molecular masses of 93, 95, and 96 kDa showed increased tyrosine phosphorylation in a time-dependent manner following GH treatment of cells that express GH receptors. GH-induced tyrosine phosphorylation of these proteins is independent of activation of protein kinase C (PKC). Cell fractionation studies revealed that the majority of tyrosine-phosphorylated pp95/96 is located in the cytoplasm. pp95 and pp96 have pIs of approx 6.2. Immunoprecipitation and Western blot analyses revealed that pp93 and pp95/96 are not immunologically related with Stat1, Stat3, Stat4, JAK2, and GHR. Thus, pp93 and pp95/96 may be important GH signal transducers independent of PKC activation and different from the characterized members in the JAK-STAT pathway.