[Bacterial community diversity in Dermatophagoides farinae using high-throughput sequencing]

OBJECTIVE

To investigate the bacterial community diversity in Dermatophagoides farinae.

METHODS

Laboratory-cultured D. farinae was collected, and the composition of microbial communities was determined by sequence analyses of the V4 region in the bacterial 16S ribosomal RNA (16S rRNA) gene on an Illumina PE250 high-throughput sequencing platform. Following quality control and filtering of the raw sequence files, valid reads were obtained and subjected to operational taxonomic units (OTU) clustering and analysis of the composition of microbial communities and alpha diversity index using the Usearch software, Silva database, and Mothur software.

RESULTS

A total of 187 616 valid reads were obtained, and 469 OTUs were clustered based on a sequence similarity of more than 97%. OTU annotation showed that the bacteria in D. farinae belonged to 26 phyla, 43 classes, 100 orders, 167 families and 284 genera. The bacteria in D. farinae were mainly annotated to five phyla of Proteobacteria, Firmicutes, Bacteroidota, Actinobacteriota, and Acidobacteriota, with Proteobacteria as the dominant phylum, and mainly annotated to five dominant genera of Ralstonia, norank-f-Mitochondria, Staphylococcus and Sphingomonas, with Wolbachia identified in the non-dominant genus.

CONCLUSIONS

A high diversity is identified in the composition of the bacterial community in D. farinae, and there are differences in bacterial community diversity and abundance among D. farinae.

[DNA barcoding of 4 species of cheyletid mites based on COI and 18S rRNA gene sequences]

OBJECTIVE

To analyze the sequences of mitochondrial cytochrome C oxidase subunit I gene (COI) and 18S ribosomal RNA gene (18S rRNA), so as to identify the feasible DNA barcodes for 4 species of cheyletid mites and improve the DNA barcoding database for cheyletid mites.

METHODS

Cheyletid mite samples were collected from small-scale flour mills in Fuyang, Wuhu and Tongling cities of Anhui Province from May 2018 to July 2019, extracted and morphologically identified. Then, genomic DNA was extracted from a single cheyletid mite, and the COI and 18S rRNA gene sequences were obtained by PCR amplification, cloning and sequencing. The obtained sequences were aligned using the BLAST software. Multiple sequence alignment was done using the software ClustalX version 1.83 using the known gene sequences from cheyletid mites. The genetic distance was calculated using the software MEGA X, and the phylogenetic tree was created using the maximum likelihood method.

RESULTS

The DNA barcoding results of Cheyletus malaccensis, C. carnifex and Cheletomorpha lepidopterorum were consistent with the morphological identification, while no sequences pertaining to Eucheyletia reticulate were retrieved in the GenBank database. The proportions of A + T were 69.6% and 55.1% in the COI and 18S rRNA sequences of 4 cheyletid mites species, respectively, and the numbers of base substitutions were 137 and 46, respectively. There were 154 to 321 and 58 to 99 inter-species variation loci in the COI and 18S rRNA gene sequences of 4 cheyletid mites species, respectively, and the intra-species genetic distance was all 0.020 or less in the COI and 18S rRNA gene sequences of 4 cheyletid mites species, with inter-species genetic distance of 0.235 to 0.583 and 0.078 to 0.114, respectively. Phylogenetic analysis based on COI and 18S rRNA genes showed that all four species of cheyletid mites were clustered into a branch with a 100% supportive rate, which was consistent with the morphological identification.

CONCLUSIONS

Mitochondrial COI gene is superior to 18S rRNA gene as DNA barcodes for 4 species of cheyletid mites, which is more suitable to be used to investigate the phylogenetic relationship of at genus and species levels.

[Changes in some elements, enzymes and energy charge in skeletal muscle of rats with spleen qi deficiency]

In order to investigate the relationship between spleen and muscle, the changes of trace elements, enzyme activity, adenine nucleotides and energy charge (EC) in the skeletal muscle of rats with Syndrome of Spleen Qi Deficiency (SQD) were studied, the curative effects of Sijunzi Tang (SJZT) for SQD were observed too. Results showed that in comparing with normal rats, the levels of ATP and EC lowered significantly (ATP P < 0.01, EC P < 0.001), the enzyme activity of the anaerobic glycolysis increased significantly (P < 0.05), the zinc and iron concentrations were higher (P < 0.01) while the copper, potassium and sodium concentrations were lower than normal significantly (P < 0.05). These changes could be corrected after treatment with SJZT for strengthening spleen and tonifying qi. Above-mentioned results suggested that the mechanism of spleen qi deficiency is closely related to the abnormal energy metabolism, and the TCM theory of spleen dominating muscles might have its scientific basis.

An immunocytochemical study of the FMRFamide neuropeptide gene products in Drosophila

We have mapped protein expression of the FMRFamide neuropeptide gene in Drosophila with polyclonal antisera against three small peptides whose sequences were derived from the Drosophila proFMRFamide precursor. One antiserum was affinity-purified and extensively characterized. The enriched antibodies labeled 15-21 bilaterally symmetric pairs of neurons in a pattern that corresponded very closely to the pattern of in situ hybridization that was determined previously (Schneider et al. [1991] J. Comp. Neurol. 304:608-622; O'Brien et al. [1991] J. Comp. Neurol. 304:623-638). The other antisera produced complementary results. These findings suggest that the antisera specifically label cells that express the FMRFamide gene. In larvae we consistently observed strong staining in identified interneurons and neuroendocrine cells, and moderate to weak staining in neurons of unknown function. The adult pattern of expression included both larval neurons whose immunoreactivity persisted through metamorphosis and adult-specific neurons. During metamorphosis, we observed transient staining in a small number of neurons and in specific neuropil regions that included the central body, the protocerebral bridge, and the optic ganglia. Based on these morphological features, we suggest that the FMRFamide-like neuropeptides in Drosophila play a number of functional roles, perhaps affecting both physiological and developmental phenomena. Such roles include general modulation throughout all post-embryonic stages, via the blood, and also more stage- and region-specific modulation within the CNS.

Characterization of 3-carboxy-5-phosphono-1,2,3,4-tetrahydroisoquinoline (SC-48981), a potent competitive (NMDA) receptor antagonist, in vitro and in vivo

(+/-)-3-Carboxy-5-phosphono-1,2,3,4-tetrahydroisoquinoline (SC-48981), a conformationally restricted analog of the potent competitive N-methyl-D-aspartate (NMDA) antagonist, 2-amino-5-phosphonopentanoate (AP-5), potently inhibited the binding of [3H]glutamate to the N-methyl-D-aspartate (NMDA) receptors with a Ki of 1.6 mcM, but with minimal affinity for kaininate and quisqualate receptors (Ki greater than 50 mcM), in vitro. Consistent with its ability to antagonize the NMDA receptor, SC-48981 decreased the binding of [3H]glycine and [3H]TCP [1-(2-thienyl)cyclohexylpiperidine] to the NMDA-associated glycine and phencyclidine (PCP) recognition sites, in vitro. SC-48981 attenuated levels of basal cGMP and harmaline-induced increases in levels of cGMP in the mouse cerebellum, in vivo, in a competitive manner, with ED50 values of 5.5 and 8.7 mg/kg, i.p. Direct intracerebellar injection of SC-48981 (0.5 microgram) attenuated increases in levels of cGMP induced by central injection of the NMDA-associated glycine receptor agonist, D-serine and by NMDA itself. Parenteral administration of SC-48981 (25 mg/kg, s.c.) decreased basal levels of cGMP for up to 3 h. These results indicate that SC-48981 represents a novel bioavailable competitive NMDA antagonist with a long duration of action.

Neuropharmacological characterization of 1-aminocyclopropane-1-carboxylate and 1-aminocyclobutane-1-carboxylate, ligands of the N-methyl-D-aspartate-associated glycine receptor

Following intravenous administration, 1-aminocyclobutane-1-carboxylate (ACBC, 100 mg/kg), a N-methyl-D-aspartate (NMDA)-associated glycine receptor antagonist, was eliminated with a T1/2 of 5 min in mouse brain and 4 min in rat cerebrospinal fluid (CSF). 1-Aminocyclopropane-1-carboxylate (ACC), a NMDA-associated glycine receptor agonist, was found to have a T1/2 of less than 5 min in mouse brain. ACC and ACBC did not alter basal cerebellar cGMP. Glycine and D-serine increased cGMP, and 1-hydroxy-3-aminopyrrolidone-2 (HA-966), a glycine antagonist, reversed the D-serine-induced increases in cGMP. In contrast, ACBC did not reverse the D-serine-induced increases in cGMP. These data suggest that despite their brain bioavailability and marked potency at the glycine receptor in vitro, ACC and ACBC are rapidly inactivated and thus have limited in vivo utility.

Synthesis of analogues of the carboxyl protease inhibitor pepstatin. Effects of structure on inhibition of pepsin and renin

Analogues of the carboxyl protease inhibitor, pepstatin, were synthesized from optically pure forms of N-(tert-butoxycarbonyl)-4-amino-3-hydroxy-6-methylheptanoic acid (Boc-Sta), and the inhibition of pepsin and renin was determined. In addition, the new amino acid (3S,4S)-4-amino-3-hydroxy-5-phenylpentanoic acid [AHPPA] was synthesized and the stereochemistry of the 3 and 4 positions established. The tripeptides isovaleryl-L-valyl-(3S,4S)-4-amino-3-hydroxy-6-methylheptanoyl-L-alanine isoamylamide [Iva-Val-(3S,4S)-Sta-Ala-NHiC5H11] and Iva-Val-(3S,4S)-AHPPA-Ala-NHiC5H11 were found to be potent inhibitors of pepsin with Ki = 1 x 10(-9) and 0.9 x 10(-9) M, respectively. Changing the chirality of the (3S)-hydroxy group to 3R or shortening the peptide chain diminished binding to pepsin over 100-fold. Three structural requirements necessary for potent inhibition of pepsin are proposed.