[Research progress on early warning model of influenza]

Influenza is an acute respiratory infectious disease caused by influenza virus. It usually exhibits seasonal transmission, but the novel influenza strain can lead to a pandemic with severe human health and socioeconomic consequences. Early warning of influenza epidemic is an important strategy and means for influenza prevention and control. On the basis of reviewing the main influenza surveillance and early warning systems, this study summarizes the principles, applications, advantages and disadvantages, and development prospects of common influenza early warning models, in order to provide reference for research and application of early warning technology for influenza and other acute respiratory infectious diseases.

[Evaluation of demand of resources for laboratory testing and prevention and control of COVID-19 in the context of global pandemic]

Objective: To rapidly evaluate the level of healthcare resource demand for laboratory testing and prevention and control of corona virus disease 2019 (COVID-19) in different epidemic situation, and prepare for the capacity planning, stockpile distribution, and funding raising for infectious disease epidemic response. Methods: An susceptible, exposed, infectious, removed infectious disease dynamics model with confirmed asymptomatic infection cases and symptomatic hospitalized patients was introduced to simulate different COVID-19 epidemic situation and predict the numbers of hospitalized or isolated patients, and based on the current COVID-19 prevention and control measures in China, the demands of resources for laboratory testing and prevention and control of COVID-19 were evaluated. Results: When community or local transmission or outbreaks occur and total population nucleic acid testing is implemented, the need for human resources is 3.3-89.1 times higher than the reserved, and the current resources of medical personal protective equipment and instruments can meet the need. The surge in asymptomatic infections can also increase the human resource demand for laboratory testing and pose challenge to the prevention and control of the disease. When vaccine protection coverage reach ≥50%, appropriate adjustment of the prevention and control measures can reduce the need for laboratory and human resources. Conclusions: There is a great need in our country to reserve the human resources for laboratory testing and disease prevention and control for the response of the possible epidemic of COVID-19. Challenges to human resources resulted from total population nucleic acid testing and its necessity need to be considered. Conducting non-pharmaceutical interventions and encouraging more people to be vaccinated can mitigate the shock on healthcare resource demand in COVID-19 prevention and control.

Isolation and characterization of polymorphic microsatellite markers for the chub mackerel (Scomber japonicus) and cross-species amplification in the blue mackerel (S. australasicus)

In this study, 10 polymorphic microsatellite markers were developed in Scomber japonicus and were examined on 30 individuals collected from the North Pacific. The number of alleles per locus ranged from 4 to 17. The observed and expected heterozygosities per locus ranged from 0.2759 to 0.8621 and from 0.43071 to 0.9177, respectively. The polymorphism information content (PIC) was from 0.3931 to 0.8939. One locus showed moderate polymorphism (0.25 < PIC < 0.5), while the rest were highly polymorphic (PIC > 0.5). Two loci showed significant deviation from Hardy-Weinberg equilibrium after Bonferroni corrections (P < 0.005). No linkage disequilibrium was detected among the loci. Results of cross-species amplification showed that 10 microsatellite markers were successfully amplified in 29 individuals of S. australasicus and 9 indicated polymorphisms. These markers will be useful for investigating the genetic structure, gene flow, and species identification of S. japonicus and S. australasicus, its closely related species.

RESEARCH ARTICLE Molecular cloning and expression analysis of a matrix Gla protein gene in the spinyhead croaker, Collichthys lucidus

The matrix Gla (gamma-carboxyglutamic acid-rich) protein (MGP), a vitamin K-dependent and Gla-containing protein, is a calcification inhibitor that mainly functions in tissue calcification and mineralization. In this study, we obtained the complete cDNA sequence of MGP from the spinyhead croaker (Collichthys lucidus), which we named Cl-MGP. Cl-MGP was 923 bp long with a 384-bp open reading fragment that encoded 127 amino acids. The predicted MGP protein sequence contained a 19-residue hydrophobic signal peptide, suggesting that it possesses secretory characteristics. The Gla domain and the invariant unit ErraEtCedyspC, which has been identified in all known vitamin K-dependent vertebrate proteins, were highly conserved in Cl-MGP, suggesting that it uses the same mechanism to function as the known proteins. An alignment analysis revealed that Cl-MGP had the highest identity with Larimichthys crocea (93%), which had lost five amino acid residues in the C-terminal. A quantitative real-time polymerase chain reaction revealed that Cl-MGP expression was highest in the gill, followed by the cholecyst and spleen, with almost no expression in the blood, muscle, or testes. The high Cl-MGP expression in the gill is similar to that observed in other fish species, but the relatively high expression found in the cholecyst and spleen is not seen in all species. Future studies should investigate the tissue distributions of both mRNA and proteins in different species, in order to understand the function and evolution of MGP in different species.

Characterization of the complete mitochondrial genome and phylogenetic relationships of the three-spot swimming crab (Portunus sanguinolentus)

In this study, we determined the whole mitochondrial genome profile of the three-spot swimming crab (Portunus sanguinolentus) and elucidated phylogenetic relationships between representative species in the order Decapoda. The mitochondrial genome was 16,024 bp in length and consisted of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a putative control region. Of the 37 genes, 23 were encoded by the heavy strand while 14 were encoded by the light strand. Four types of start codons were identified; ATG initiated nine genes, ATT initiated two genes, and ATC and GTG each started one gene. Nine protein-coding genes ended with a complete TAA or TAG stop codon, and four genes ended with an incomplete T or TA codon. Fourteen non-coding regions were found, which ranged from 1 to 34 bp in length. Nine overlaps were observed, with lengths between 1 and 7 bp. Phylogenetic analysis suggested that P. sanguinolentus is genetically closest to P. trituberculatus and P. pelagicus. Charybdis feriata, C. japonica, and Thalamita crenata formed a single cluster, and were close to the genera Callinectes and Portunus. Therefore, the genera Charybdis and Thalamita should be classified into the subfamily Portuninae.

Optimization of selective breeding through analysis of morphological traits in Chinese sea bass (Lateolabrax maculatus)

Determining correlations between certain traits of economic importance constitutes an essential component of selective activities. In this study, our aim was to provide effective indicators for breeding programs of Lateolabrax maculatus, an important aquaculture species in China. We analyzed correlations between 20 morphometric traits and body weight, using correlation and path analyses. The results indicated that the correlations among all 21 traits were highly significant, with the highest correlation coefficient identified between total length and body weight. The path analysis indicated that total length (X₁), body width (X₅), distance from first dorsal fin origin to anal fin origin (X₁₀), snout length (X₁₆), eye diameter (X₁₇), eye cross (X₁₈), and slanting distance from snout tip to first dorsal fin origin (X₁₉) significantly affected body weight (Y) directly. The following multiple-regression equation was obtained using stepwise multiple-regression analysis: Y = -472.108 + 1.065X₁ + 7.728X₅ + 1.973X₁₀ - 7.024X₁₆ - 4.400X₁₇ - 3.338X₁₈ + 2.138X₁₉, with an adjusted multiple-correlation coefficient of 0.947. Body width had the largest determinant coefficient, as well as the highest positive direct correlation with body weight. At the same time, high indirect effects with six other morphometric traits on L. maculatus body weight, through body width, were identified. Hence, body width could be a key factor that efficiently indicates significant effects on body weight in L. maculatus.

Characterization of the complete mitochondrial genome of Portunus pelagicus with implications for phylogenomics

This study determined the mitochondrial genome structure of the blue swimming crab (Portunus pelagicus), and elucidated its phylogenetic relationships among the species within the order Decapoda. The complete mitochondrial genome was 16,155 bp long, and contained 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 DNA control region. The gene order of the genome was the same as that found within the family Portunidae. Twenty-three genes were on the heavy strand and 14 were on the light strand. Almost all of the protein-coding genes were initiated by an ATG codon, except for three genes (ATP6, ND1, and ND3) that started with a rare ATT codon. Of the 13 protein-coding genes, 10 ended with complete TAA or TAG stop codons and three ended with an incomplete T codon. Thirteen non-coding regions were identified that ranged from 1 to 30 bp in length. Nine overlaps were found, which ranged 1 to 7 bp in length. Phylogenetic analyses based on 12 concatenated protein-coding genes revealed that P. pelagicus formed a monophyletic group with Portunus trituberculatus, which were in a larger group with Callinectes sapidus, while the genera Charybdis and Thalamita formed another group. These two groups clustered together and grouped with the genus Scylla. The phylogenetic analysis supported the inclusion of Charybdis in subfamily Portuninae of the family Portunidae, and revealed a close relationship between Charybdis and Thalamita. We suggest that Thalamita should also be classified into the subfamily Portuninae. The results can be used in the study of phylogenetic, population genetic and conservation genetics of P. pelagicus.

Molecular cloning and gene expression analysis of cystatin C-like proteins in spinyhead croaker Collichthys lucidus

Cystatins are natural tight-binding reversible inhibitors of cysteine proteases. In this study, a cDNA library was constructed from Collichthys lucidus using the SMART technique. A complete cDNA sequence with high identity to the conserved sequence of the cystatin C gene was cloned from the library using EST analysis and rapid amplification of cDNA ends (RACE), then subjected to further investigation. The full-length cDNA of cystatin C from C. lucidus (Clcys) was 699 bp long, including a 5'-terminal untranslated region (5'-UTR) of 52 bp, a 3'-UTR of 290 bp, and an open-reading frame of 357 bp. The gene encoded a polypeptide of 118 amino acids, constituting a predicted molecular weight of 12.875 kDa and a theoretical isoelectric point of 8.81. The amino acid sequence of Clcys possessed typical features of type II cystatins and had the highest identity with cystatin C of Pseudosciaena crocea (89%); therefore, it clustered with the cystatin C group in the UPGMA phylogenetic tree. Quantitative real-time reverse transcription analysis revealed that the highest expression was found in the kidney, followed by the liver, heart, and testis, with the lowest expression in muscle. Interestingly, Clcys had relatively low identity with cystatin C genes from other fish and mammals, and its expression pattern did not possess features of a housekeeping gene. Based on these findings, we suspect that the classification of cystatins in fish is somewhat confusing, and the identification of more cystatin gene sequences is needed before a definite conclusion can be drawn.

Spin-orbit coupling of light in asymmetric microcavities

When spinning particles, such as electrons and photons, undergo spin-orbit coupling, they can acquire an extra phase in addition to the well-known dynamical phase. This extra phase is called the geometric phase (also known as the Berry phase), which plays an important role in a startling variety of physical contexts such as in photonics, condensed matter, high-energy and space physics. The geometric phase was originally discussed for a cyclically evolving physical system with an Abelian evolution, and was later generalized to non-cyclic and non-Abelian cases, which are the most interesting fundamental subjects in this area and indicate promising applications in various fields. Here, we enable optical spin-orbit coupling in asymmetric microcavities and experimentally observe a non-cyclic optical geometric phase acquired in a non-Abelian evolution. Our work is relevant to fundamental studies and implies promising applications by manipulating photons in on-chip quantum devices.

Characterization, molecular cloning, and expression analysis of Ecsit in the spinyhead croaker, Collichthys lucidus

Evolutionarily conserved signaling intermediate in Toll pathways (Ecsit) is reported to play an essential role in innate immunity, embryogenesis, and assembly or stability of the mitochondrial complex I. In this study, the full-length cDNA of Ecsit was cloned from the spinyhead croaker Collichthys lucidus based on the expressed sequence tags from our cDNA library constructed using the SMART technique. The cDNA was 1669 bp long, including a 5'-terminal untranslated region (UTR) of 121 bp, a 3'-terminal UTR of 183 bp, and an open reading frame of 1365 bp encoding a 454-amino acid polypeptide. The estimated molecular weight of C. lucidus Ecsit (ClEcsit) was 52.50 kDa with an isoelectric point of 6.14, and contained a typical Ecsit domain that is conserved in other Ecsits. Multiple alignment of ClEcsit with other selected Ecsits suggested that some amino acid residues were highly conserved. Phylogenetic analysis indicated that ClEcsit was more similar to its identities in Sciaenidae and grouped with Ecsits from other Perciformes. Quantitative real-time reverse transcription PCR analysis revealed broad expression of ClEcsit and the transcript was strongly expressed in the gill and weakly expressed in other tissues.

Characteristics of growth traits and their effects on body weight of G₁ individuals in the mud crab (Scylla paramamosain)

The mud crab (Scylla paramamosain) is considered a potentially important marine crab species for selective breeding. Here, we first examined sex ratio and differences in 16 growth traits between females and males in a G1 population of S. paramamosain, and we then analyzed the correlation between these growth traits and their effects on body weight (BW). Of these growth traits, nine were significantly different between sexes. In females, the correlation coefficients in all trait pairs ranged from 0.524 to 0.997. The traits carapace length (CL) and distance between lateral spine 2 (DLS2) significantly affected BW directly, with the path coefficients being 1.124 and -0.186, respectively. The determination coefficients of traits CL and DLS2 to BW were 1.263 and 0.035 with the total value being 0.951, indicating that the two traits were the key factors affecting BW. In males, the correlation coefficients in all trait pairs ranged from 0.881 to 0.999. The three traits body height (BH), fixed finger height of the claw (FFHC), and meropodite length of pereopod 2 (MLP2) significantly affected BW directly, with the path coefficients being 0.484, 0.300, and 0.225, respectively. The determination coefficients of traits BH, FFHC and MLP2 to BW were 0.234, 0.090 and 0.051, with the total value being 0.967, indicating that these three traits played a key role in affecting BW. Moreover, we constructed two best-fit linear regression equations, which were Y (BW) = 4.969 X1 (CL) - 0.758 X2 (DLS2) - 140.177 and Y (BW) = 3.806 X1 (BH) + 2.371 X2 (FFHC) + 1.725 X3 (MLP2) - 123.559 in females and males, respectively.

Development and testing of 13 polymorphic microsatellite markers in Larimichthys polyactis (Sciaenidae) using 5' anchored PCR

Larimichthys polyactis is a commercially important marine fish species in southeast Asia. The population crashed due to overfishing in the 1970s, but has since recovered. We developed 13 novel polymorphic microsatellite markers in L. polyactis using 5' anchored PCR. The characteristics of these loci were estimated by analyzing a sample of 30 individuals. A total of 74 alleles were detected, with a mean of 5.7 alleles per locus. There were 2 to 12 alleles, 0.2760 to 0.8247 polymorphism information content, and 0.3214 to 1.000 observed and 0.3097 to 0.8567 expected heterozygosity per locus. The mean observed and expected heterozygosity was 0.6816 and 0.6724, respectively. Three loci deviated significantly from Hardy-Weinberg equilibrium after Bonferroni's correction, and no significant linkage disequilibrum between pairs of loci was found. This information will be useful for the analysis of population genetic diversity, and the management of this important fish resource.

Effects of enzyme addition on the nutritive value of broiler diets containing hulled or dehulled Chinese double-low rapeseed meals

An in vitro and a feeding trial was conducted to investigate the effect of fibre-degrading enzymes A (xylanase + β-glucanase), B (xylanase) and C (xylanase + cellulase) on the nutritive value of broiler diets containing either hulled (22.5% and 23.5% for 4–21 days and 22–42 days of age, respectively) or dehulled (20% and 21.5%) Chinese double-low rapeseed meals (DLRM). Overall, in vitro digestibility of dry matter (DM) or neutral digestibility fibre (NDF) did not differ (p > 0.05) because of meal types; both crude protein (CP) and NDF digestibility was improved (p < 0.05) because of addition of enzymes B or C either to hulled or dehulled DLRM diets. Birds fed dehulled DLRM diets had a higher (p < 0.05) growth rate, feed efficiency and lower (p < 0.05) feed intake than those fed hulled DLRM diets during the overall phase. Enzyme C addition to dehulled DLRM diets resulted in improved (p < 0.05) growth rate and feed efficiency during 4–21 days of age. Enzymes A and B addition elicited a positive response in feed intake and weight gain (p < 0.05), respectively, but did not affect (p > 0.05) feed efficiency. It would appear that the nutritive value of broiler diets containing Chinese DLRM could be improved by appropriate xylanase-based enzymes. Responses of broilers to fibre-degrading enzymes could be highlighted by hull removal of fed DLRM.

[Structure determination of three saponins from the stem bark of Albizzia julibrissin Durazz]

Three new saponins named Julibroside J1, J2 and J3 were isolated from the stem bark of Albizzia julibrissin Durazz (Albizziae Cortex). Based on chemical and spectral methods, e.g. 1H- and 13C-NMR, DEPT, COSY CH-COSY, TOCSY, HMQC-COSY, HMQC-TOCSY, NOESY, HMBC, their structures have been identified as; Julibroside J1 (one triterpene, nine sugars, two monoterpenes I); Julibroside J2(one triterpene, eight sugars two monoterpenes II); Julibroside J3(one triterpene, nine sugars two monoterpenes III).

[Separation and identification of the flavonoids from Buddleia officinalis Maxim]

The flowers of Buddleia officinalis Maxim have been used to cure eye inflammation in China. Eight flavonoid compounds were isolated from them. Their structures were characterized as acacetin (1), apigenin (2), luteolin (3), neobudofficide (4), linarin (acaciin 5), luteolin-7-O-rutinoside (6), luteolin-7-O-glucoside (7) and cosmosiin (8), on the basis of chemical and spectral evidences. The new compound 4 was identified as 5,7-dihydroxy-4'-O-methoxyflavone-7-O-alpha-L-rhamnopyranosyl (1-->2)-[alpha-L-rhamnopyranosyl (1-->6)]-beta-D-glucopyranoside and named neobudofficide. All the compounds were isolated from B. officinalis for the first time, except linarin and acacetin.

Triterpenoid saponins from Bupleurum smithii var. parvifolium

Four triterpenoidal saponins, prosaikogenin A and saikosaponins b1, n and o, were isolated from the roots of the title plant for the first time. Saikosaponin O is a new compound, which was identified as 3 beta,16 beta,23,28-tetrahydroxyolean-11,12(18)-diene-3-O-beta-D-glucopy ran osyl-(1-->2)-beta-D-glucopyranosyl-(1--> 6)-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranoside.

Flavonol glycosides from Epimedium koreanum

A novel flavonol glycoside named caohuoside-B was isolated from the aerial parts of Epimedium koreanum, along with a known flavonol glycoside, epimedokoreanoside-I. Their structures were established by spectroscopic methods. The new compound was elucidated as anhydroicaritin 3-O-beta-D-(4,6-O- diacetyl)glucopyranosyl-(1-->3)-alpha-L-(4"-O-acetylrhamnopyranoside+ ++)-7-O-beta- D-glucopyranoside.

Structure and expression of the human XPBC/ERCC-3 gene involved in DNA repair disorders xeroderma pigmentosum and Cockayne's syndrome

The human XPBC/ERCC-3 was cloned by virtue of its ability to correct the excision repair defect of UV-sensitive rodent mutants of complementation group 3. The gene appeared to be in addition implicated in the human, cancer prone repair disorder xeroderma pigmentosum group B, which is also associated with Cockayne's syndrome. Here we present the genomic architecture of the gene and its expression. The XPBC/ERCC-3 gene consists of at least 14 exons spread over approximately 45 kb. Notably, the donor splice site of the third exon contains a GC instead of the canonical GT dinucleotide. The promoter region, first exon and intron comprise a CpG island with several putative GC boxes. The promoter was confined to a region of 260 bp upstream of the presumed cap site and acts bidirectionally. Like the promoter of another excision repair gene, ERCC-1, it lacks classical promoter elements such as CAAT and TATA boxes, but it shares with ERCC-1 a hitherto unknown 12 nucleotide sequence element, preceding a polypyrimidine track. Despite the presence of (AU)-rich elements in the 3'-untranslated region, which are thought to be associated with short mRNA half-life actinomycin-D experiments indicate that the mRNA is very stable (t 1/2 greater than 3h). Southern blot analysis revealed the presence of XPBC/ERCC-3 cross-hybridizing fragments elsewhere in the genome, which may belong to a related gene.