Volatile-compound fingerprinting and discrimination of positional isomers in stamp-pad ink tracing using HS-GC-IMS combined with multivariate statistical analysis.

The rising crime rate associated with document forgery has a significant impact on public safety and social stability. In document fraud cases, determining the origin of a particular stamp-pad ink is the most important objective. In this study, a comprehensive analysis of the volatile compounds in quick-drying stamp-pad inks from six commonly used brands were performed for the first time, utilizing a combination of headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and multivariate statistical analysis methods. Visual and comparative analysis of the differential volatile components among different stamp-pad ink samples was conducted using fingerprints and volcano plots. A total of 127 volatile compounds were accurately identified, with ketones, esters, alcohols, and aldehydes being the most abundant compounds in the stamp-pad inks. Hierarchical clustering analysis (HCA), including dendrograms and clustering heatmaps, was utilized to explore the correlations between these compounds and the samples. Additionally, the precise identification of positional isomers and functional group isomers of aliphatic compounds was achieved. To achieve accurate discrimination of various stamp-pad ink samples, a multivariate statistical analysis method was utilized to establish a classification model for them. Based on the results obtained from HS-GC-IMS, effective discrimination among different brands of stamp-pad ink samples was achieved through principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). The model exhibited excellent performance, with the fit index of dependent variables (R2Y) and the predictive index of the model (Q2) values of 0.99 and 0.984, respectively. These results provided significant theoretical evidence for the application of HS-GC-IMS as an efficient technique in the analysis of volatile compounds, identification of positional isomers and functional group isomers, as well as tracing the origin of stamp-pad ink and analyzing the formation time of documents.

Advances in forensic diagnosis of electric shock death in the absence of typical electrical marks.

Electrical injury is a relatively uncommon but potentially devastating form of multi-system injury with high morbidity and mortality. In common electric injury cases, it is usually difficult to find characteristic changes of electric injury in major organs by using routine histopathological test methods unless there are landmark traces of electric injury, known as electric marks. How to determine electric shock death, especially in the absence of typical electrical marks on the body surface in some cases (which account for about two-thirds of electric injury cases), remains a challenging problem in forensic practice. Our summary shows that many current related studies have focused their efforts to find characteristic histopathological changes in major organs of the body caused by electric injury. Based on the results obtained through comparison of the literature, we find that it may be more urgent and important to find the optimal autopsy or sampling sites in cases with no typical electric marks, knowing that these sites may often reflect the most significant histopathological changes of electric injury, for instance anatomy and sampling of the anterior wrist and the medial malleolus in cases involving the hand-to-foot electric circuit pathway. In this article, we make a summary of advances in identification methods of electric injury, hoping that it could provide some new insights for further research in this field.

[Study on the Antioxidant Activity of Aloe-Emodin Metal Complex].

OBJECTIVE: To synthesize three kinds of metal complexes of aloe-emodin and compare the antioxidant activities of the ligands and the complexes. METHODS: Three kinds of aloe emodin metal complex, the aloe-emodin-iron (Ⅱ), the aloe-emodin-copper (Ⅱ) and the aloe-emodin-magnesium (Ⅱ) complexes, were synthesized by dissolving and stirring in anhydrous ethanol solvent, and their structures were characterized. The Fe 2+-H 2O 2-methylene blue method, the diphenyl bitter hydrazine radical method (DPPH method) and other assays were used to determine the clearance effect of ligands and complexes on superoxide radicals (O 2 －•), hydroxyl radicals (•OH) and phenyl bitter hydrazine radical (DPPH•). RESULTS: Three kinds of aloe emodin metal complex, the aloe-emodin-iron (Ⅱ), the aloe-emodin-copper (Ⅱ) and the aloe-emodin-magnesium (Ⅱ) complexes, were successfully synthesized. According to the results of structural characterization, we speculated that the aloe-emodin metal complexes were formed at the site between the two molecules of aloe-emodin and one molecule of metal ions (Fe 2+, Mg 2+, Cu 2+) via the 9 th carbonyl and 8 th hydroxyl groups of the aloe-emodin molecules. Both the complex and the ligand have clearance effects on three kinds of free radicals, and the complex showed stronger effects than its ligand ( P<0.05). CONCLUSION: Coordination of aloe-emodin with metal ions, such as Fe 2+, Cu 2+, and Mg 2+, could enhance the antioxidant activity of the ligand itself.

Haplotype analysis of 36 Y-STR loci in a Chinese Han population from Anhui Province, Eastern China.

We analyzed haplotypes for 36 Y chromosomal STRs (Y-STRs), including 27 Yfiler Plus loci and 9 additional STRs (DYS549, DYS643, DYS508, DYS447, DYS596, DYS444, DYS557, and DYS527a/b) in 2018 unrelated Chinese Han individuals from Anhui Province using DNATyperTM 36Y Kit. Phylogenetic analysis was performed to determine the genetic relationship of the Anhui Han population with other neighboring and/or linguistically close populations.

Revisit of gastromalacia: a report of three cases and review of the literature.

Gastromalacia, a postmortem dissolution of the stomach, is caused by endogenous enzymes resulting in thinning and softening of the stomach wall with focal perforation. Thus, identifying gastromalacia and differentiating it from other causes of gastric perforation is essential to avoid misdiagnosis. Herein, three cases of gastromalacia are described. The victims died due to hyperthermia, leukemia complicated by cerebral hemorrhage, and asphyxia due to inhaled vomitus, respectively. The macroscopic and microscopic appearance in three cases indicated gastromalacia, although multiple factors confused the diagnosis. Furthermore, the differential diagnosis and the underlying mechanism are discussed.

microRNA221 is Involved in Human Placental Development by Targeting DDIT4.

BACKGROUND/AIMS: miR221 might have an important role in human embryo development. However, little is known about the function of miR221 in the human embryo. The aim of this study was to evaluate miR221 expression in human placental tissue, and to analyze the relationship between miR221 and target genes. METHODS: The human placentas tissue samples were collected from healthy pregnant women who were willing to terminate their pregnancy. The total RNA isolation and microRNA reverse transcription quantification were performed by TaqMan microRNA assay and qRT-PCR. RESULTS: The results showed that miR221 expression was significantly higher in 55- to 71-day placenta (mean value=0.1049) than that in 38- to 54- day (the mean value=0.0133) (p<0.001). miR221 targeting genes, such as PIK3R1, CDKN1B, CDKN1C, DDIT4, and FOS, were detected in human placenta tissue, but only DDIT4 was significantly decreased with development (mean value: 0.0101 for 38∼54 days, 0.0021 for 55∼71 days, p<0.001). Further analysis showed that only DDIT4 was negatively correlated with miR221 expression (DDIT4: r=-0.396, p=0.033; PI3KR: r=0.322, p=0.089; CDKN1B: r=0.298, p=0.128; CDKN1C: r=0.198, p=0.304; FOS: r=0.171, p=0.347). CONCLUSION: These findings indicate that miR221 might play an important role in human placental development by precisely regulating the DDIT4 expression.

Mir-382 Promotes Differentiation of Rat Liver Progenitor Cell WB-F344 by Targeting Ezh2.

BACKGROUND/AIMS: Liver progenitor cells (LPCs) were considered as a promising hepatocyte source of cell therapy for liver disease due to their self-renewal and differentiation capacities, while little is known about the mechanism of LPC differentiate into hepatocytes. This study aims to explore the effect of miR-382, a member of Dlk1-Dio3 microRNA cluster, during hepatic differentiation from LPCs. METHODS: In this study, we used rat liver progenitor cell WB-F344 as LPC cell model and HGF as inducer to simulate the process of LPCs hepatic differentiation, then microRNAs were quantified by qPCR. Next, WB-F344 cell was transfected with miR-382 mimics, then hepatocyte cell trait was characterized by multiple experiments, including that periodic acid schiff staining and cellular uptake and excretion of indocyanine green to evaluate the hepatocellular function, qPCR and Western Blotting analysis to detect the hepatocyte-specific markers (ALB, Ttr, Apo E and AFP) and transmission electron microscopy to observe the hepatocellular morphology. Moreover, Luciferase reporter assay was used to determine whether Ezh2 is the direct target of miR-382. RESULTS: We found that miR-382 increased gradually and was inversely correlated with the potential target, Ezh2, during WB-F344 hepatic differentiation. In addition, functional studies indicated that miR-382 increased the level of hepatocyte-specific genes. CONCLUSIONS: This study demonstrates that miR-382 may be a novel regulator of LPCs differentiation by targeting Ezh2.

Population genetic analysis of the Globalfiler STR loci in 3032 individuals from the Altay Han population of Xinjiang in northwest China.

The genetic polymorphisms of 21 autosomal short tandem repeat (STR) loci included in the GlobalFiler™ PCR Amplification Kit were evaluated in 3032 unrelated individuals Altay Han of Xinjiang, northwest China. All of the loci reached the Hardy-Weinberg equilibrium. These loci were examined to determine allele frequencies and forensic statistical parameters. SE33 showed the greatest power of discrimination in Altay Han population, whereas TPOX showed the lowest. The combined discrimination power and probability of excluding paternity of the 21 autosomal STR loci were 0.999999999999999999999999889838 and 0.999999996664704, respectively. Both pairwise genetic distance and phylogenetic methods indicated that the Altay Han had the closest genetic relationship with the Han origin and Hui populations. The present results revealed that the GlobalFiler system had a high level of polymorphism in Altay Han population and hence could be a powerful tool for forensic application and population genetic study.

Toward Understanding the Cold, Hot, and Neutral Nature of Chinese Medicines Using in Silico Mode-of-Action Analysis.

One important, however, poorly understood, concept of Traditional Chinese Medicine (TCM) is that of hot, cold, and neutral nature of its bioactive principles. To advance the field, in this study, we analyzed compound-nature pairs from TCM on a large scale (>23 000 structures) via chemical space visualizations to understand its physicochemical domain and in silico target prediction to understand differences related to their modes-of-action (MoA) against proteins. We found that overall TCM natures spread into different subclusters with specific molecular patterns, as opposed to forming coherent global groups. Compounds associated with cold nature had a lower clogP and contain more aliphatic rings than the other groups and were found to control detoxification, heat-clearing, heart development processes, and have sedative function, associated with "Mental and behavioural disorders" diseases. While compounds associated with hot nature were on average of lower molecular weight, have more aromatic ring systems than other groups, frequently seemed to control body temperature, have cardio-protection function, improve fertility and sexual function, and represent excitatory or activating effects, associated with "endocrine, nutritional and metabolic diseases" and "diseases of the circulatory system". Compounds associated with neutral nature had a higher polar surface area and contain more cyclohexene moieties than other groups and seem to be related to memory function, suggesting that their nature may be a useful guide for their utility in neural degenerative diseases. We were hence able to elucidate the difference between different nature classes in TCM on the molecular level, and on a large data set, for the first time, thereby helping a better understanding of TCM nature theory and bridging the gap between traditional medicine and our current understanding of the human body.

[Species Identification of Puparium Samples of Common Sarcosaphagous Flies Based on Molecular Marker Analysis].

OBJECTIVE: To investigate the application value of empty puparia in species identification of common sarcosaphagous flies. METHODS: Fifty-five samples of adult flies and their empty puparia were collected. All the samples were identified as 2 families, 6 genera and 8 species by morphological characteristics. The samples were divided into 3 groups according to their time period between eclosion and our analyses: less than 2 years (n = 23), 2-5 years (n = 20), and more than 5 years (n = 12). The mtDNA of each sample was extracted by CTAB method. The purity and concentration of DNA were tested. PCR products were amplified using two sets of primers. Two sequences of CO I gene (sequence I: 498 bp, sequence II : 841 bp) from each sample were compared to the sequences in GenBank using BLAST for species identification. RESULTS: The mtDNA was extracted successfully from all the samples. DNA concentration of adult chest muscle preserved less than or equal to 5 years and empty puparia preserved less than 2 years ranged from 1.0 to 3.0 µg/µl, and the value of A260/A280 ranged from 1.6 to 1.8. The purity and concentration was lower than 1.6 and 1.0 µg/µl, when the adult chest muscle and empty puparia preserved more than 5 years and 2 years, respectively. DNA concentration of the samples significantly decreased with the prolonged preservation time (P < 0.01). Two sequences of CO I gene was amplified in adult chest muscle and empty puparia which preserved less than 2 years. The success rates of amplification decreased with the prolonged preservation time, especially for the sequence II (P < 0.01). The morphological identification of 8 species did not match exactly with the results based on the COI gene, correct species identification occurred in 6 and 7 species out of 8 based on the two sequences, respectively, and their Max ident value exceeded 97% CONCLUSION: Empty puparium samples can be used to extract mtDNA and identify species.

Magnetic bead-based separation of sperm from buccal epithelial cells using a monoclonal antibody against MOSPD3.

Forensic DNA analysis of sexual assault evidence requires unambiguous differentiation of DNA profiles in mixed samples. To investigate the feasibility of magnetic bead-based separation of sperm from cell mixtures using a monoclonal antibody against MOSPD3 (motile sperm domain-containing protein 3), 30 cell samples were prepared by mixing 10(4) female buccal epithelial cells with sperm cells of varying densities (10(3), 10(4), or 10(5) cells/mL). Western blot and immunofluorescence assays showed that MOSPD3 was detectable on the membrane of sperm cells, but not in buccal epithelial cells. After biotinylated MOSPD3 antibody was incubated successively with the prepared cell mixtures and avidin-coated magnetic beads, microscopic observation revealed that each sperm cell was bound by two or more magnetic beads, in the head, neck, mid-piece, or flagellum. A full single-source short tandem repeat profile could be obtained in 80% of mixed samples containing 10(3) sperm cells/mL and in all samples containing ≥10(4) sperm cells/mL. For dried vaginal swab specimens, the rate of successful detection was 100% in both flocked and cotton swabs preserved for 1 day, 87.5% in flocked swabs and 40% in cotton swabs preserved for 3 days, and 40% in flocked swabs and 16.67% in cotton swabs preserved for 10 days. Our findings suggest that immunomagnetic bead-based separation is potentially a promising alternative to conventional methods for isolating sperm cells from mixed forensic samples.

The effect of dietary fat levels on the size and development of Chrysomya megacephala (Diptera: Calliphoridae).

Variation in the type of tissue that larvae feed on can produce marked differences in developmental rate and body size, which can compromise predictions of minimum postmortem interval. A series of experiments were conducted to investigate the effect of fat content in the diet on larval growth in Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), an important forensic blowfly species in China. Bionomical parameters such as body size, development time, mortality, and sex ratio were observed. The results indicated that fat content in the diet has a dramatic effect on the body size and larval development. More dietary fat content was beneficial for development of larvae in first and early second instar. But it was adverse in the later third instar. Significantly, a high-fat diet resulted in increased development rates and the production of undersized larvae and adults. Overall mortality of larvae and pupa was higher when more fat was added to the diet, but sex ratio of adults was not negatively affected. This study highlights that the fat content in the diet should be considered in the entomological research and forensic application when estimating minimum postmortem interval on the basis of larval body size and developmental stage.

[Effect of diets with different fat levels on the body size and development of Lucilia sericata].

OBJECTIVE: To observe the effect of diets with different fat levels on the body size and development of Lucilia sericata. METHODS: Under the constant temperature of 28 degrees C, the larvae were reared on the diets containing 0% (G0), 10% (G1), 30% (G3), 50% (G5) and 80% (G8) fat tissues (fat/muscle ratio), respectively. Length and weight of larvae and pupae were measured at 12 h interval since 16 h after eclosion. Length of inter-medial cross vein (m-m) of adult left wing was measured. 10 samples were collected in each group. The developmental duration time, mortality and sex ratios of adults were recorded. RESULTS: The mean maximal larval length [(13.3 +/- 1.2), (12.0 +/- 1.1), (10.2 +/- 0.9) and (8.8 +/- 0.8) mm, respectively] and mean maximal larval weight [(72.8 +/- 6.1), (62.2 +/- 5.7), (47.2 +/- 4.3), and (34.9 +/- 5.7) mg] in G1, G3, G5 and G8 groups were significantly less than that of the G0 group [(14.8 +/- 1.3) mm and (80.4 +/- 8.1) mg](P < 0.01). The body size of pupae and adults was also significantly less than that of G0 group (P < 0.01). The total duration time of G5 and G8 groups [(293.3 +/- 22.2) and (285.2 +/- 24.6) h] were significantly shorter than that of G0 group [(312.8 +/- 20.1)h] (P < 0.01). The mortality of larvae [(32.6 +/- 5.6)% and (44.3 +/- 7.7)%] and pupae [(28.6 +/- 5.5)% and (43.5 +/- 6.2)%] of G5 and G8 group were also significantly higher than that of G0 group [(5.7 +/- 3.3)% and (4.5 +/- 1.9)%] (P < 0.01). There was no significant difference in sex ratio among the 5 groups (P > 0.05). CONCLUSION: The body size of larvae, pupae and adults of Lucilia sericata is smaller, the development time is shorter and mortality is higher when the food substrate contains more fat tissues.

Y-STR analysis of highly degraded DNA from skeletal remains over 70 years old.

The goal of the following study is to clarify whether the skeletal remains over 70 years old from missing persons and their alleged relatives shared identical Y-STR loci. Nowadays, advances in ancient DNA extraction techniques and approaches of using multiple different Y-STRs have significantly increased the possibility of obtaining DNA profiles from highly degraded skeletal remains. Given the ages and conditions of the skeletal remains, ancient DNA extraction methods can be used to maximize the probability of DNA recovery. Considering that information about distant relatives is more relevant for long-term missing persons and alleged family members are male, Y-STR loci analysis is considered the most appropriate and informative approach for determining paternal lineage relationship. In this study, Y-STR genotypes obtained from these alleged relatives were identical to each other and to the alleles of missing persons' consensus profiles at more than 22 loci examined, whilst not being found in Y-STR population database from Y-Chromosome STR Haplotype Reference Database. Therefore, Missing Person No.7 and Missing Person No.18 have a patrilineal relationship with reference samples from Family1 and Family2, respectively. In addition, the fact that Y-STR haplotypes obtained from skeletal remains of missing persons and reference samples are not found in the Han Chinese people from East Asian demonstrates its rarity and further supports a paternal lineage relationship amongst them.

Synergistic effects of exogenous IAA and melatonin on seed priming and physiological biochemistry of three desert plants in saline-alkali soil.

To investigate the synergistic effect of IAA and melatonin (MT) on three plants to alleviate the effects of salt damage on plants, we aim to determine the optimal concentrations of exogenous hormone treatments that improve salinity resistance for each species. In this experiment, three desert plants, Sarcozygium xanthoxylon, Nitraria tangutorum, and Ammopiptanthus mongolicus, which are common in Wuhai City, were used as plant materials. Two time periods (12 h,24 h) of exogenous hormone IAA (100 µmol/L) and exogenous melatonin concentration (0, 100, 200, 300 µmol/L) were used to treat the three desert plants in saline soil under different conditions of exogenous IAA and exogenous melatonin. The results indicate that under different concentrations of exogenous IAA and melatonin, the germination rate and vigor of the three desert plant species in saline-alkaline soil improved. However, as the concentration of melatonin increased, the germination rate and vigor of these desert plants were inhibited. Whereas, plant height, root length, leaf length, fresh weight, dry weight, and root vigor of the three desert plants were alleviated under different conditions of exogenous IAA and exogenous melatonin. under the action of two exogenous hormones, the low concentration of melatonin decreased their malondialdehyde content and increased their proline content. As melatonin levels increased, the activity of antioxidant enzymes also rose initially, followed by a subsequent decline. This study highlights the synergistic effects of two exogenous hormones on the critical role of cell osmomodulators and antioxidant enzyme activity in combating salinity damage in three desert plants.

Analysis and discrimination of adhesive species using ATR-FTIR combined with Raman, and HS-GC-IMS together with multivariate statistical analysis.

Identifying the species and origin of adhesives in criminal investigations aids in narrowing inquiry scope and supporting case detection. This study introduces two advanced combined analytical techniques for distinguishing adhesive species, including attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) combined with Raman spectroscopy, and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) together with multivariate statistical analysis. ATR-FTIR categorized seven adhesives into three groups based on the base materials, with further differentiation achieved via Raman spectra. Analysis of volatile components identified 79 volatile organic compounds (VOCs), with esters being the most concentrated. The fingerprint profile clearly illustrated the characteristic fingerprint sequence and unique marker compounds of each adhesive, effectively enabling their differentiation. Multivariate statistical analysis methods, including principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), heatmap, and hierarchical cluster analysis (HCA), were utilized to visually interpret the classification of adhesives. This integrated analytical approach provides a comprehensive analysis of adhesive compositions, facilitating the diversification and precision of adhesive species identification, and broadening the scope for detecting and analyzing trace evidence in forensic science.

Insect chitosan/pullulan/gallium photo-crosslinking hydrogels with multiple bioactivities promote MRSA-infected wound healing.

Methicillin-resistant Staphylococcus aureus (MRSA) and other drug-resistant bacteria have become more common in recent years, which has made it extremely difficult to treat and heal many different kinds of wounds and caused enormous financial losses. Because of its unique "Trojan horse" function, Ga3+ has been recognized as a new possible candidate for inhibiting and eradicating drug-resistant bacteria. Furthermore, natural polysaccharide materials with outstanding biological characteristics, such as insect chitosan (CS) and pullulan (PUL), have attracted significant interest. In this study, we used quaternized-catechol chitosan (QDCS-PA), methacrylate-dialdehyde pullulan (DPUL-GMA), and gallium ion (Ga) to create a multi-crosslinked photo-enhanced hydrogel (Q-D/Ga/UV) with antimicrobial, hemostatic, self-healing, and injectable properties for promoting MRSA-infected wound healing. In vitro, the Q-D/Ga/UV hydrogels demonstrated good mechanical properties, antioxidant capabilities, biocompatibility, hemostatic properties, and antibacterial activity. The addition of gallium ions enhanced the hydrogels' mechanical properties, hemostatic capabilities, antibacterial activity, and ability to induce wound healing. Q-D/Ga/UV hydrogel significantly promoted wound contraction, collagen deposition, and angiogenesis while also suppressing inflammation in a whole-skin wound model of MRSA-infected rats. In conclusion, Q-D/Ga/UV hydrogels demonstrate significant promise for healing wounds infected with drug-resistant bacteria.

Mucoadhesive and thermosensitive Bletilla striata polysaccharide/chitosan hydrogel loaded nanoparticles for rectal drug delivery in ulcerative colitis.

Ulcerative colitis (UC) is a chronic disease with diffuse mucosal inflammation limited to the colon. A topical drug delivery system that could be facilely performed and efficiently retained at colon are attractive for clinical ulcerative colitis treatment. Herein, a novel platform for rectal administration of thermosensitive hydrogel co-loaded with nanoparticles to treat ulcerative colitis was developed. Thiolated-hyaluronic acid was synthesized, and prepared nanoparticles with zein and Puerarin. And the Bletilla striata polysaccharide with colonic mucosa repair effect was oxidized, and mixed with chitosan and ß-sodium glycerophosphate to prepare thermosensitive hydrogel. Thermosensitive hydrogels were combined with nanoparticles to investigate their mucosal adhesion, retention, and permeability, as well as their therapeutic effects on ulcerative colitis. Thiolated-hyaluronic acid nanoparticles had good stability, and could be quickly converted into hydrogel at body temperature when combined with thermosensitive hydrogel. The nanoparticles-loaded thermosensitive hydrogel also was excellent at mucosal penetration, enhancing the retention time of drugs in colon, and effectively controlling drug release. In vivo ulcerative colitis treatment revealed that the nanoparticles-loaded hydrogel significantly repaired the colonic mucosa and inhibit colonic inflammation. Therefore, the thermosensitive hydrogel co-loaded nanoparticles will have a promising application in effective treatment of ulcerative colitis by topical administration.

Characteristics and Comparative Analysis of Six Mitogenomes of Genus Kiefferulus Goetghebuer, 1922 (Diptera: Chironomidae).

Chironomidae is a cosmopolitan and species-rich family of insects, with many species serving as useful indicators of aquatic ecosystem health. In this study, we newly sequenced six species of Kiefferulus Goetghebuer, 1922 (Chironomidae: Chironominae) by high-throughput sequencing technology. We analyzed characters of the mitochondrial genome, including the sequence length, nucleotide composition, and evolutionary rates of this genus. The size of the newly obtained sequences ranged from 15,588 to 15,767 bp, and all of them included 22 tRNAs, 13 PCGs, 2 rRNAs, and 1 CR. The CR showed the highest AT content relative to the PCGs, rRNAs, and tRNAs. Relative synonymous codon usage analysis showed that UUA, UUU, and AUU are the preferred codons. The ratio of nonsynonymous (Ka) to synonymous (Ks) substitution rates showed that all Ka/Ks of PCGs were lower than 1, with ATP8 having the highest evolution rate, while COX1 exhibited the lowest evolution rate. We reconstructed the phylogenetic relationship of the genus Kiefferulus based on eight species (six ingroups and two outgroups), using five matrices and employing Maximum likelihood and Bayesian inference approaches. Phylogenetic analysis of the Kiefferulus showed that six species within this genus were classified into a monophyletic clade.

Odor Fingerprinting of Chitosan and Source Identification of Commercial Chitosan: HS-GC-IMS, Multivariate Statistical Analysis, and Tracing Path Study.

Chitosan samples were prepared from the shells of marine animals (crab and shrimp) and the cell walls of fungi (agaricus bisporus and aspergillus niger). Fourier-transform infrared spectroscopy (FT-IR) was used to detect their molecular structures, while headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was employed to analyze their odor composition. A total of 220 volatile organic compounds (VOCs), including esters, ketones, aldehydes, etc., were identified as the odor fingerprinting components of chitosan for the first time. A principal component analysis (PCA) revealed that chitosan could be effectively identified and classified based on its characteristic VOCs. The sum of the first three principal components explained 87% of the total variance in original information. An orthogonal partial least squares discrimination analysis (OPLS-DA) model was established for tracing and source identification purposes, demonstrating excellent performance with fitting indices R2X = 0.866, R2Y = 0.996, Q2 = 0.989 for independent variable fitting and model prediction accuracy, respectively. By utilizing OPLS-DA modeling along with a heatmap-based tracing path study, it was found that 29 VOCs significantly contributed to marine chitosan at a significance level of VIP > 1.00 (p < 0.05), whereas another set of 20 VOCs specifically associated with fungi chitosan exhibited notable contributions to its odor profile. These findings present a novel method for identifying commercial chitosan sources, which can be applied to ensure biological safety in practical applications.