Effect of inoculating mixed starter cultures of Lactobacillus and Staphylococcus on bacterial communities and volatile flavor in fermented sausages

The objective of this study was to explore the effects of the inoculation of mixed starter cultures of Lactobacillus and Staphylococcus(labeled L-S)on microbial community and flavor in fermented sausages during the ripening process.Culture-dependent(colony count)and culture-independent(high-throughput sequencing)methods were employed to evaluate bacterial communities.Volatile compounds were identified by gas chromatography-mass spectrometry,and the results were analyzed by principal component analysis(PCA).The identified bacteria with high relative abundance included Lactobacillus and Pediococcus,and the relative abundances of Leuconostoc and Weissella in fermented sausages were remarkably decreased at the end of the ripening process.At the end of ripening,2-nonenal,tetradecanal,ethylstearate and terpinyl acetate played substantial roles in the flavor development of the L-S fermented sausages.Sensory evaluation showed a high score in the L-S fermented sausages.Sausages can be inoculated with L-S starter culture to improve the safety and flavor of meat products.

Cobalt Sulfide Confined in N-Doped Porous Branched Carbon Nanotubes for Lithium-Ion Batteries

Lithium-ion batteries(LIBs) are considered new generation of large-scale energy-storage devices.However,LIBs suffer from a lack of desirable anode materials with excellent specific capacity and cycling stability.In this work,we design a novel hierarchical structure constructed by encapsulating cobalt sulfide nanowires within nitrogen-doped porous branched carbon nanotubes(NBNTs)for LIBs.The unique hierarchical Co9S8@NBNT electrode displayed a reversible specific capacity of 1310 mAhg-1 at a current density of 0.1 Ag-1,and was able to maintain a stable reversible discharge capacity of 1109 mAhg-1 at a current density of 0.5 Ag-1 with coulombic efficiency reaching almost 100% for 200 cycles.The excellent rate and cycling capabilities can be ascribed to the hierarchical porosity of the one-dimensional Co9S8@NBNT internetworks,the incorporation of nitrogen doping,and the carbon nanotube confinement of the active cobalt sulfide nanowires offering a proximate electron pathway for the isolated nanoparticles and shielding of the cobalt sulfide nanowires from pulverization over long cycling periods.

Genome-wide identification and expression analysis of NIN-like Protein(NLP)genes reveals their potential roles in the response to nitrate signaling in watermelon

To balance the relationship between high yield and low nitrogen supply,the nitrogen utilization efficiency of watermelon needs to be improved urgently.Nodule inception-like Protein(NLP)transcription factors play a key node role in nitrate response and growth and development of plant,however,comprehensive analysis of the NLP gene family in watermelon is unclear.This study explored the functional classification,evolutionary characteristics,and expression profile of the ClNLP gene family.Three ClNLPs were categorized into three groups according to their gene structure and phylogeny.All of them contained the conserved RWP-RK and PB1 domains.Evolutionary analysis of ClNLPs revealed that ClNLP1 and ClNLP3 underwent strong purified selection.In addition,cis-acting elements related to plant hormones and abiotic stresses were present in the ClNLP promoter.According to tissue-specific analysis ClNLP was widely expressed in roots,stems,leaves,flowers and fruits,and ClNLP1 was significantly induced in the roots of different nitrogen utilization varieties under different nitrate nitrogen supply.The SRTING functional protein association network suggested that ClNLP1 is associated with most genes,such as NRT1.1,NRT2.1,NIA1,and NIR1,and the dual-luciferase reporter assay found that ClNLP1 positively regulates the expression of ClNRT2.1.We speculated that ClNLP1 might play a central role in regulating the response of watermelon to nitrate nitrogen.

Selection of nitrite-degrading and biogenic amine-degrading strains and its involved genes

Objectives:Accumulation of nitrite and biogenic amines(BAs)in fermented meat products is a matter of public health concern.The study aimed to screen nitrite-degrading and BA-degrading strains from sour porridges and sausages and bacon products in China.Materials and Methods:After screening out 12 strains,the degradation of nitrite,the degradation of BAs,the activities of nitrite-reducing enzymes,and the detection of genes involved in the BAs were assessed by spectrophotometry method with hydrochloric acid naphthalene ethylenediamine,high-performance liquid chromatography,GENMED kit,and polymerase chain reaction,respectively.Results:Pediococcus pentosaceus labelled M SZ12 and M GC 2,Lactobacillus plantarum labelled M SZ22,and Staphylococcus xylosus labelled Y CC 3 were selected.The activity of nitrite-reducing enzyme in M SZ22 was 2.663 units/mg.The degradation rate of total BAs of M SZ22 was 93.24%.The degradation rates of nitrite and BAs of M SZ12 were 86.49%and 37.87%,respectively.The activity of nitrite-reducing enzyme in M SZ12 was up to 1.962 units/mg.M GC 2 showed higher degradation rates of nitrite(89.19%)and Y CC 3 showed higher degradation rates of BAs(36.16%).The genes encoding the multicopper oxidases(suf I/D2EK17)were detected in the four strains,which also did not contain BAs(histidine decarboxylase(hdc),tyrosine decarboxylase(tdc),ornithine decarboxylase(odc),lysine decarboxylase(ldc))formation encoding genes.Conclusion:These four strains(M SZ12,M GC 2,M SZ22,and Y CC 3)are promising candidates to use as starter cultures for nitrite and BAs in fermented sausages.

Crystallographically-Oriented Nanoassembly by ZnS Tricrystals and Subsequent Three-Dimensional Epitaxy

Chemistry gives us the ability to manipulate atoms and molecules into nanometer and micrometer scale building blocks,while the science of crystallography is concerned with the spatial arrangement of atoms,ions,and molecules and thus the morphology and structures of materials.Complex three-dimensional ZnS nanostructures have been fabricated via step-by-step crystallographically-controlled chemical processes.Tricrystals of ZnS whiskers were prepared via a controlled thermal evaporation process,and then the tricrystals were thermally treated in an atmosphere formed by evaporating B N O precursors into N2/NH3 to afford BN-coated arrays of nanobranches.The ZnS nanobranches grew epitaxially on the ternary facets and extended in three[0001]directions forming ordered nanostructures.Meanwhile,the protecting insulating sheath of BN formed on the ZnS nanostructures confined the growth of the nanospines and enhanced their stability.The method may be extended to fabricate other semiconductor nanomaterials with novel structures.