Effects of L-lysine·H2SO4 product on the intestinal morphology and liver pathology using broiler model

Background: Lysine is used widely in livestock production due to the shortage of feed protein resources.Llysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus.However,there are few articles about L-lysine·H2SO4 product regarding intestinal morphology and liver pathology of broiler chickens.In this article,we focus on the absorption and metabolism of L-lysine·H2SO4 revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H2SO4.Methods: To evaluate the tolerance of broilers for L-lysine·H2SO4,240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0,1%,4%,7% or 10% L-lysine·H2SO4(L-lysine content = 55%).Results: Supplementation of 1% L-lysine·H2SO4 in the diet had no negative effects.However,4%,7% or 10% Llysine·H2SO4 supplementation produced negative responses on broiler performance,carcass characteristics,blood biochemistry,and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet.Conclusion: Our results show that supplementation with 1% L-lysine·H2SO4 had no negative effects on performance,carcass characteristics,blood biochemistry,intestinal morphology and liver pathology in broilers,but supplementation with 4%,7% or 10% L-lysine·H2SO4 produced a negative response,particularly with respect to intestinal morphology and liver pathology.

Escherichia coli Protoplast Fusion and Screening of High L-Lysine-Producing Strain

[Objectives]Protoplast fusion of two parental strains with weak L-lysine production ability was carried out to obtain new fusion strains with strong L-lysine production ability.[Methods]The effects of bacterial age,lysozyme concentration,enzymolysis temperature and time on the protoplast formation rate and regeneration rate were investigated by single factor experiments.On this basis,with the protoplast formation rate as an index,the protoplast preparation process was optimized by an orthogonal experiment.[Results]Bacterial age and enzymolysis time had a greater impact on the protoplast formation rate,followed by enzymolysis temperature and lysozyme concentration.The optimal process for the preparation of L-lysine-producing Escherichia coli protoplasts was to prepare parental protoplasts from bacterial cells cultured for 15 h in the late logarithmic growth phase by enzymolysis with 0.8 mg/ml lysozyme at 37℃for 180 min and promote fusion with PEG6000.In order to facilitate the screening of fusion protoplasts,the empty plasmids p ET-28a and p ET-Duet were transformed into L-lysine-producing E.coli,respectively,and strains p ET-28a-lys01 and p ET-Duet-lys01 were obtained.Fusion strains were then obtained through protoplast fusion.Double-resistance KA1-10were screened on plates containing kanamycin and ampicillin,and a high-yielding fusion strain KA8,which produced L-lysine,was screened by fermentation experiments finally.[Conclusions]The results of this study provide a reference method for further improving the yield of L-lysine and other amino acid strains.

Effect of L-lysine in culture medium on nodule formation by bone marrow cells

The aim of this study was to estimate the effect of L-lysine on nodule formation by rat bone marrow cells in vitro. In this study, L-lysine was added to medium for mesenchymal stem cell culture to promote proliferation and differentiation of the cells, and then nodule formation was estimated in an in vitro rat bone marrow cell culture. Bone marrow cells from the bone shafts of the femora of Fischer 344 rats were cultured in minimum essential medium with 20 μl of L-lysine solution at 10﹣4, 10﹣5, 10﹣6, 10﹣7 or 10﹣8 M. Dexamethasone was also added to the medium at 10 nM for differentiation of stem cells from bone marrow into osteoblast progenitor cells. The subculture was performed for 2 weeks. The quantity of osteocalcin in rat bone marrow cell culture with dexamethasone was 392 ng/ml. In the medium with dexamethasone and 10﹣8 M L-lysine, the quantity of osteocalcin was 437 ng/ml. Nodules only formed upon addition of 20 μl of L-lysine at 10﹣8 M. It was indicated that 10﹣8 M L-lysine should be the optimal concentration for calcification. For nodule formation by rat bone marrow cells in vitro, the optimum concentration of L-lysine in culture medium might be 20 μl of 10﹣8 M. L-lysine could play an important role in matrix production for bone formation in vitro.

Dissolution of highly molecular weight cellulose isolated from wheat straw in deep eutectic solvent of Choline/L-Lysine hydrochloride

Green solvents for cellulose dissolution is a key topic for green chemistry,especially natural cellulose with high molecular weight,and there are scarce solvents reported.Deep eutectic solvent(DES)is a typical kind of green solvent that has been attracted much attention recently.Here,high molecular weight natural cellulose(DP>3000)was first isolated from wheat straw and then be directly dissolved in the choline/L-lysine(Ch/Lys)DES.The solution owns excellent stability,and the solubility reaches^5%.Rheological studies revealed that the natural cellulose can be well dispersed in the DES solution and showed gelation at high concentrations.The dissolved cellulose can be regenerated when the dilute acid aqueous solution was added into the solution.It provides an energy conversation and an environmentally friendly route to prepare a cellulose solution,which makes it possible to convert cellulose to valuable chemicals and materials in its homogeneous solution.

A NEW BIFUNCTIONAL CHELATING AGENT α,ε-N,N'-BIS(L-CYSTEINYL)-L-LYSINE FOR RADIOLABELLING OF MONOCLONAL ANTIBODIES WITH TECHNETIUM-99M

α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment F(ab')_2 of anti-gastric tumor monoclonal antibody 3G9.The radiolabelled antibody was satisfactorily stable and immunoreactive.

De novo transcriptome assembly of Aureobasidium melanogenum CGMCC18996 to analyze theβ-poly(L-malic acid)biosynthesis pathway under the CaCO_(3) addition

β-Poly(L-malic acid)(PMLA)is a water-soluble biopolymer used in food,medicine and other industries.To date,the biosynthesis pathway of PMLA has not been fully elucidated.In this study,we sequenced the transcriptom e of strain Aureobasidium melanogenum under 20 g/L CaCO_(3) addition.The resulting sequencing reads were assembled and annotated for the differentially expressed genes(DEGs)analysis and novel transcripts identification.The result indicated that with the CaCO_(3) addition,the tricarboxylic cycle(TCA)cycle and glyoxylate pathway were up-regulated,and it also found that a non-ribosomal peptide synthetase(NRPS)like protein was highly expressed.The DEGs analysis showed a high expression level of malate dehydrogenase(MDHC)and phosphoenolpyruvate carboxykinase(PCKA)in the CaCO_(3) group,which indicated a cytosolic malate activity.We speculated that the malate should be transported to or synthesized in the cytoplasm,which was then polymerized to PMLA by the NRPS-like protein,accompanied by the up-regulated TCA cycle providing ATP for the polymerization.Depending on the analysis,we assumed that an NRPS-like protein,the TCA cycle,and the cytosolic malate together are contributing to the PMLA biosynthesis.

Synthesis and Hydrophilic Performance of Poly(Lactic Acid)-Poly(Ethylene Glycol) Block Copolymers

Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and 1H nuclear magnetic resonance (1H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.

Photodegradation Behavior of Polycaprolactone-Poly(ethylene glycol)Block Copolymer

The biodegradation behavior in vitro and in vivo of polycaprolactone-poly (ethylene glycol) block copolymer (PCE) was reported in detail. In this paper, photodegradation test of PCE was performed by exposure to UV light. The mechanical properties and the inherent viscosity of PCE samples which are subjected to photodegradation were determined. The experimental results indicated that poly (ethylene glycol) (PEO) segment in PCE copolymer is photosensitive. The photodegra-dation rate of the PCE was increased with increasing poly (ethylene glycol) content.

High-gravity technology intensified Knoevenagel condensation-Michael addition polymerization of poly (ethylene glycol)-poly (n-butyl cyanoacrylate) for blood-brain barrier delivery

Poly(ethylene glycol)-poly(n-butyl cyanoacrylate)(PEG-PBCA)is a remarkable drug delivery carrier for permeating blood-brain barrier.In this work,a novel high-gravity procedure was reported to intensify Knoevenagel condensation-Michael addition polymerization of PEG-PBCA.A series of PEG-PBCA containing different block ratios were synthesized with narrow molecular weight distribution of polydispersity indexes less than 1.1.Furthermore,the reaction time reduced 60%compared to conventional stirred tank reactor process.Chemical structures of as-prepared polymers were characterized.In vitro drug delivery performance was evaluated.The cytotoxicity of PEG-PBCA to brain microvessel endothelial cells(BMVEC)decreases with the extension of the PEG chain and the shortening of the PBCA chain.The polymer cellular uptake to BMVECs was better after improving hydrophilicity by PEG block.Results of bloodbrain barrier permeability demonstrated that medium length of PBCA chain and short PEG chain are favorable for hydrophobic Nile red permeation,while long PEG chain and short PBCA chain are beneficial to delivery water-soluble doxorubicin hydrochloride(Dox).The average apparent permeability coeffi-cient increased 1.7 and 0.25 times than that of raw Nile red and Dox,respectively.High-gravity intensi-fied condensation polymerization should have great potential in brain drug delivery system.

Mechanical, Thermal and Morphology Properties of Thermoplastic Polyurethane Copolymers Incorporating α,ω-Dihydroxy-[poly(propyleneoxide)-poly (dimethylsiloxane)-poly(propyleneoxide)] of Varying Poly(propyleneoxide) Molecular Weight

Novel segmented thermoplastic polyurethane (TPU) copolymers were synthesized using two-step solventless bulk polymerization. 4,4’-methylenediphenyl diisocyanate (MDI) and 1,4-Butanediol (BDO) were used to form hard segment of TPU and α,ω-dihydroxy-[poly(propyleneoxide)-poly (dimethylsiloxane)-poly(propyleneoxide)] (α,ω-dihydroxy-(PPO-PDMS-PPO)) was used to form soft segment of TPU, where the molar ratio of the –N=C=O/OH was 1.02 and the hard segment weight percentage was 30%. A series of TPUs were characterized by fourier transform infrared spectroscopy (FT-IR). The investigation of triblock oligomer’s PPO molecular weight impact on the derived TPU’s mechanical properties, thermal performance, surface water repellency and morphology performance was carried by Instron material tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), water contact angles (WCA), scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDX) and wide angle X-ray diffraction (WAXD), respectively. FT-IR confirmed α,ω-dihydroxy-(PPO-PDMS-PPO) well cooperating into urethane structure and analyzed hydrogen bonding between N-H group with hard segment C=O group and N-H group with soft segment C-O-C group. DSC and WAXD results showed α,ω-dihydroxy-(PPO-PDMS-PPO) segments crystallization. SEM-EDX results showed that the presence of a spherulitic morphology, which arose from the crystallization of the PPO segments. The thermal properties measured by TGA and DSC were slightly affected by molecular weight of PPO and microphase separation. The weight loss of TPUs started between 294°C and 300°C, and Tg was in the range of -70°C to -107°C. TPU copolymers’ surface hydrophobicity property was excellent with WCA range of 95°?to 112°. TPU-3 with 1000 molecular weight PPO has the optimized mechanical properties with tensile strength 16.4 MPa and the modulus at 100% elongation 6.2 MPa and elongation 398%.

ε-Poly(L-lysine)-based Hydrogels with Fast-acting and Prolonged Antibacterial Activities

Bacterial infections and the associated morbidity and mortality due to bacterial pathogens in wounds and medical implants have been increasing as most of current coatings cannot fulfill all the requirements including excellent intrinsically antibacterial activity, low cytotoxicity, and favorable physical properties. Herein, we present a kind of antibacterial bydrogel based on e-poly（L-lysine） （EPL） grafted carboxymethyl chitosan （CMC-g-EPL） as the inherently antibacterial matrix and the surplus EPL as highly efficient antimicrobial agent. Such hydrogels possess tunable swelling abilities with water absorption percentages of 800%-2000% and modulus varying from 10 kPa to 100 kPa, and exhibit two-stage excellent antibacterial behavior. First, the free EPL can be released from the hydrogel network for quick and highly efficient bacteria killing with 99.99% of efficacy; second, the grafted EPL endows bydrogel matrix with prolonged intrinsically antibacterial activity, especially when most of free EPL is released from the hydrogel. Overall, we provide a new insight for preparing highly effective antibacterial hydrogels.

Scale-up Efficient Synthesis of α-Poly(L-lysine)

α-Poly(_(L)-lysine)(α-PLL)is a water-soluble cationic biopolymer containing the monomeric unitα-_(L)-lysine,which not only possesses excellent intrinsic properties but also can be modified via facile reactions between the side amine groups and many other functional moieties.Ring-opening polymerization(ROP)is the most prevalently used technique for the synthesis of PL_(L)-based polypeptides,which involves initial conversion of theε-primary amine-protectedα-_(L)-lysine to the _(L)-lysine NCA monomer.However,obtaining N-carboxyanhydrides(NCAs)in high purity has been a formidable challenge for over 50 years,let alone the large-scale synthesis.Herein,we show an unprecedented scale-up synthesis of _(L)-Cbz-LysNCA monomer and its polymers,generating linearα-poly(_(L)-lysine)with molecular weight(MW)up to 13.4 kDa.This easy operated scale-up strategy will lay the foundations for the industrial preparation of _(L)-Cbz-LysNCA and its polymers,and further extend the realm of existing applications,offering a paradigm for scale-up synthesis of other polypeptides.

A study on α-ketoadipic aciduria by gas chromatographic-mass spectrometry

INTRODUCTIONα-ketoadipate(α-KA),an intermediate in thecatabolism of L-lysine,hydroxylysine,and L-tryptophan,undergoes oxidative deearboxylation toform glutaryl-CoA and then dehydrogenates to formcrotonyl-CoA,the latter undergoes furtherdegradation and enters in TCA cycle,as shown inFigure 1.α-ketoadipic aciduria (Mckusick 245130)is a rare inborn error in the metabolism of α-KA

Green synthesis of gold nanoclusters using papayajuice for detection of L-lysine

Gold nanoclusters were rapid synthesized within 3 min at 120 ℃ by using papaya juice as a capping and reducing agent(P-AuNCs). The properties of the fluorescent probe were characterized by fluorescent spectroscopy, UV-vis spectroscopy, dynamic light scattering and transmission electron microscope.Based on the surface electron density increase-induced fluorescence enhancing principle, a high selective method for detection of L-lysine was developed with the as-prepared P-AuNCs coupling the fluorescence emission at 440 nm. The fluorescent probe showed high stability and good biocompatibility. Its fluorescence intensity was found to be linearly dependent on the L-lysine concentration in the range of 10.0μmol/L to 1000.0 μmol/L(R^2=0.969) with a limit of detection of 6.0μmol/L. Furthermore, the PAuNCs based approach was applied for monitoring the urine L-lysine contents, demonstrating great potential of fluorescent probes in real samples analysis.

FABRICATION AND AFM/FFM STUDIES OF C_(60)-CONTAINING POLYELECTROLYTE SELF-ASSEMBLED FILMS

An initial investigation on the roughness and frictional properties of the self-assembled thin films from polyelectrolytes is presented. Star-shaped C-60-Poly(styrene-maleic anhydride) was successful prepared. The multilayer thin films have been fabricated on mica with diazoresin as the cationic polyelectrolyte and hydrolyzed star-shaped C-60-poly(styrene-maleic anhydride) as the anionic polyelectrolyte via self-assembly technique. The crosslinking structure of the films is formed from the conversion of ionic bond to covalent bond after UV irradiation. AFM/FFM investigations provide insights into the roughness and frictional properties on a microscale. The roughness depends strongly on the number of film layers in the case of C-60-containing films. The frictional forces of the films exhibited a well behaved non-linear relationship in response to the change of applied load. It supports the prediction of enhanced load-bearing property Of C60-containing thin films.

Syntheses and Characterization of Metal Complexes of L－Lysine－N，N，N＇，N＇－tetraacetic Acid and L－Lysine－N，N，N＇，N＇－tetramethylenepho sphonic Acid

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L-Lysine/imidazole-catalyzed Multicomponent Cascade Reaction： Facile Synthesis of C5-substituted 3-Methylcyclohex-2-enones

A facile and simple route for the direct preparation of substituted 3-methylcyclohex-2-enone via Aldol- Robinson cascade reaction of aldehydes and acetones catalyzed by the new catalytic system of L-lysine/imidazole in n-heptane with 0.5% water was reported. A variety of substrates can participate in the process efficiently. The merits of this method included inexpensive and easily available starting materials and catalyst, the good yield of products and the straightforward work-up.

Interfacial synthesis and properties of L-lysine-derived optically active poly(ester-imide)s

L-Lysine hydrochloride was transformed to ethyl L-lysine dihydrochloride.This salt was reacted with trimellitic anhydride to yield the corresponding diacid（1）.Intertacial polycondensation results novel poly（ester-imide）s（PEI_（a-i））.These polymers have inherent viscosities in the range of 0.23-0.47 dl g^（-1）,display optical activity,and are readily soluble in polar aprotic solvents.They start to decompose（T_（10%）） above 350℃and display glass-transition temperatures at 100.42-172.81℃.All of the above polymers were fully characterized by UV,FT-IR and ~1H NMR spectroscopy,elemental analysis,TGA,DSC,inherent viscosity measurement and specific rotation.

Composite Eu-MOF@CQDs“off&on”ratiometric luminescent probe for highly sensitive chiral detection of l-lysine and 2-methoxybenzaldehyde

The high amount of l-lysine can increase the potential risk of cardiovascular disease.Additionally,2-methoxy benzaldehyde(2-MB)has high toxicity and can easily pollute the environment.In this work,carbon quantum dots(CQDs)can be encapsulated into Eu-BTB(H_(3)BTB=1,3,5-tri(4-carboxyphenyl)benzene),forming the multi-emission composite material Eu-BTB@CQDs.It has two emissions peaks(617 nm for Eu and 470 nm for CQDs).Eu-BTB@CQDs can be applied as bi-functional ratiometric“off&on”luminescent sensor for l-lysine and 2-MB with high sensitivity and selectivity,the low limit of detection(LOD)for l-lysine is 3.68μmol/L and for 2-MB is 0.54μmol/L,respectively.Additionally,Eu-BTB@CQDs can quantitatively discriminate l-lysine in the mixed d-and l-lysine water solutions(five different concentrations ratio of l/d-lysine has been set)makes the chiral detection of l-lysine are more meaningful.On the other hand,Eu-BTB@CQDs also can detect 2-MB over 4-methoxybenzaldehyde(4-MB)with high selectivity.Further the detection of 2-MB and l-lysine in the lake water real samples with the reasonable recovery rate.Finally,the detection mechanisms for l-lysine and 2-MB were also investigated and discussed in detail.

Co-delivery of resveratrol and docetaxel via polymeric micelles to improve the treatment of drug-resistant tumors

Co-delivery of anti-cancer drugs is promising to improve the efficacy of cancer treatment.This study was aiming to investigate the potential of concurrent delivery of resveratrol(RES)and docetaxel(DTX)via polymeric nanocarriers to treat breast cancer.To this end,methoxyl poly(ethylene glycol)-poly(D,L-lactide)copolymer(mPEG-PDLA)was prepared and characterized using FTIR and 1H NMR,and their molecular weights were determined by GPC.Isobologram analysis and combination index calculation were performed to find the optimal ratio between RES and DTX to against human breast adenocarcinoma cell line(MCF-7 cells).Subsequently,RES and DTX were loaded in the mPEG-PDLA micelles simultaneously,and the morphology,particle size distribution,in vitro release,pharmacokinetic profiles,as well as cytotoxicity to the MCF-7 cells were characterized.IC50 of RES and DTX in MCF-7 cells were determined to be 23.0μg/ml and 10.4μg/ml,respectively,while a lower IC50 of 4.8μg/ml of the combination of RES and DTX was obtained.The combination of RES and DTX at a ratio of 1:1(w/w)generated stronger synergistic effect than other ratios in the MCF-7 cells.RES and DTX loaded mPEG-PDLA micelles exhibited prolonged release profiles,and enhanced cytotoxicity in vitro against MCF-7 cells.The AUC(0→t)of DTX and RES in mPEG-PDLA micelles after i.v.administration to rats were 3.0-fold and 1.6-fold higher than that of i.v.injections of the individual drugs.These findings indicated that the co-delivery of RES and DTX using mPEG-PDLA micelles could have better treatment of tumors.