The matrix plays a prominent role in expanding the ability
of matrix
assisted laser desorption/ionization mass spectrometry (MALDI MS).
However, on account of the unclarity of necessary properties of the
matrix in MALDI MS, development of a new matrix is still in the exploratory
stage and lacks systematic theoretical guidance. Meanwhile, most of
the existing matrices are unable to simultaneously detect various
high-molecular-weight (high-MW) lipids including (poly-)phosphoinositides,
cardiolipins, and gangliosides. In this study, we have successfully
screened and optimized the application of commercially available IR-780
as a novel matrix for simultaneously profiling and imaging high-MW
lipids in brain tissues by MALDI MS for the first time. The properties
of IR-780 related to the matrix of MALDI MS, mainly including the
optical properties (UV absorption, fluorescence emission, and photothermal
efficiency), proton affinity, collision cross-sections (CCSs), salt-tolerance
ability, and homogeneity, were comprehensively characterized, which
demonstrated that high photothermal ability and large CCSs might guarantee
the superior performance of IR-780 as matrix for the analysis of high-MW
lipids in biological samples. This work provided some references for
the development of a novel matrix, and especially, the concept of
CCS was first introduced as a parameter for the development of a matrix.
In addition, the simultaneous identification and imaging of endogenous
high-MW lipids in rat brain tissues subjected to traumatic brain injury
were successfully performed.
This study investigates the preparation of ligustrazine hydrochloride carboxymethyl chitosan and collagen microspheres. This experiment investigates effects of the ratio of carboxymethyl chitosan and collagen blend, water to oil ratio, stirring speed, and other factors on the microsphere properties. The experiment had the following conditions: a 1:2 proportion of carboxymethyl chitosan and collagen, a 1:2 proportion of drugs and materials, a 5:1 proportion of oil phase and water phase, 0.5% of span80, a 600r/min stirring speed, 3 ml of a cross-linking agent, 3 h of crosslinking curing, 1.25 § 0.05 mm diameter LTH microcapsules, a 54.08% envelop rate, and a 14.16% carrier rate. The microspheres release rate reached 66% within 1 h, then steadily released within 5 h in vitro. The experimental results showed that the ligustrazine hydrochloride microsphere production process was stable and exhibited a good release effect compared with other ligustrazine hydrochloride tablets and pills.
A novel ribonuclease (RNase) A superfamily gene (Rdronc) has been cloned from the frog Rana dybowskii. The deduced amino acid sequence shows that it belongs to the ribonuclease A superfamily, with the highest identity, 73%, to Rana pipiens onconase. Adaptive evolution analysis based on maximum likelihood models of codon substitution has been conducted on 10 members of the Rana RNases of subcluster B. Rapid adaptive evolution and multiple positive selection sites have been detected, which indicates that these genes may be evolving under positive selection pressure. Functional assay demonstrates that the recombinant Rdronc protein possesses antimicrobial activity against Gram-negative Escherichia coli and Pseudomonas aeruginosa and weaker antimicrobial activity against Gram-positive Staphylococcus aureus and yeast Candida albicans. Our findings support the hypothesis that ribonuclease A superfamily members may function in host defense of early-diversified vertebrates.
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