Hopf bifurcation, stability switches and chaos in a prey-predator system with three stage structure and two time delays.

A three stage-structured prey-predator model with digestion delay and density dependent delay for the predator is investigated. The stability of the equilibrium point and the Hopf bifurcation of the system by choosing time delay as a bifurcation parameter in five cases are considered, and the conditions for the positive equilibrium occurring local Hopf bifurcation are given in each case. Numerical results show that delayed system considered has not only periodic oscillation, stability switches but also chaotic oscillation, even unbounded oscillation. Finally, delays induced Hopf bifurcation, stability switches, complicated dynamic behaviors of the system are discussed in detail.

Deciphering transcriptome profile of the yellow catfish (Pelteobagrus fulvidraco) in response to Edwardsiella ictaluri.

Edwardsiella ictaluri is one of the most important pathogens posing a serious threat for yellow catfish (Pelteobagrus fulvidraco), a highly valuable fish species of increasing commercial interest in China. Here, a transcriptomic strategy was undertaken to investigate the yellow catfish gene expression profile against infection by the bacterial pathogen E. ictaluri. Comparison of the transcriptome profiles between the infected and uninfected samples showed that a massive gene expression change occurred in yellow catfish following bacterial exposure. A total of 5527 differentially expressed genes (DEGs) were detected, of which 2265 showed up-regulation and 3262 down-regulation. Gene set enrichment analysis revealed the presence of canonical pathways directly linked to innate and adaptive immune response, such as pattern recognition receptor (PRR) signaling pathways, complement and coagulation cascades, as well as T-cell receptor (TCR) and B-cell receptor (BCR) signaling pathways. Additionally, 47,526 putative EST-liked simple sequence repeats (SSRs) markers were retrieved for use in genetic studies. This study establishes the first molecular clues to understand the potential mechanisms of yellow catfish resistance to E. ictaluri, thus enabling future efforts on disease control programs in this valuable aquaculture species.

De novo annotation of the immune-enriched transcriptome provides insights into immune system genes of Chinese sturgeon (Acipenser sinensis).

Chinese sturgeon (Acipenser sinensis), one of the oldest extant actinopterygian fishes with very high evolutionary, economical and conservation interest, is considered to be one of the critically endangered aquatic animals in China. Up to date, the immune system of this species remains largely undetermined with little sequence information publicly available. Herein, the first comprehensive transcriptome of immune tissues for Chinese sturgeon was characterized using Illumina deep sequencing. Over 67 million high-quality reads were generated and de novo assembled into the final set of 91,739 unique sequences. The annotation pipeline revealed that 25,871 unigenes were successfully annotated in the public databases, of which only 2002 had significant match to the existing sequences for the genus Acipenser. Overall 22,827 unigenes were categorized into 52 GO terms, 12,742 were classified into 26 KOG categories, and 4968 were assigned to 339 KEGG pathways. A more detailed annotation search showed the presence of a notable representation of immune-related genes, which suggests that this non-teleost actinopterygian fish harbors the same intermediates as in the well known immune pathways from mammals and teleosts, such as pattern recognition receptor (PRR) signaling pathway, JAK-STAT signaling pathway, complement and coagulation pathway, T-cell receptor (TCR) and B-cell receptor (BCR) signaling pathways. Additional genetic marker discovery led to the retrieval of 20,056 simple sequence repeats (SSRs) and 327,140 single nucleotide polymorphisms (SNPs). This immune-enriched transcriptome of Chinese sturgeon represents a rich resource that adds to the currently nascent field of chondrostean fish immunogenetics and furthers the conservation and management of this valuable fish.

[Fechtner syndrome, a nonmuscle myosin heavy chain 9 gene mutation related disease: a case report and literature review].

OBJECTIVE: To improve the recognition of Fechtner syndrome. METHODS: The clinical and laboratory data and family survey of a patient with Fechtner's syndrom was reported. RESULTS AND CONCLUSION: Giant platelets, thrombocytopenia and characteristic granulocyte inclusion bodies (Döhle-like bodies) were found in both peripheral blood and bone marrow smears of the patient. Clinically the patient had renal damage, nervous deafness, and vitreous lesions. There was a family genetic tendency on family survey the diagnosis of Fechtner syndrome is established.

[Enhancement of As-accumulation by Pteris vittata L. affected by microorganisms].

A pot experiment was carried out to study the root character and As accumulation of Pteris vittata L. affected by actinomycete PSQ, shf2 and bacteria Ts37, C13. The results indicated that growth of the fern was improved by the microorganisms. The biomass, root activity and root volume of shf2 treatment were 11.5 g/pot, 2.01 microg/(g x h), 38.3 mL, which were higher than those of other microorganisms treatments. Arsenic concentrations in the plants treated by the microorganisms were higher than that of the control treatment. The As concentration of leaves in Ts37 treatment was up to 837 mg/kg, 206% more than that of the control. The As concentration of root treated by shf2 is 427 mg/kg, 88% more than that of the control. The arsenic accumulation by the plant in microorganism treatments was higher than that of the control, especially shf2 treatment up to 5804 microg/pot, 136% more than that of the control. The phytoremediation efficiency of the fern in greenhouse experiment after 45d was from 8.9% to 11.3%. The ability of As-accumulation of Pteris vittata is greatly enhanced by application of microorganism, and actinomycete shf2 is proved as the perfect one.

Using protein design to dissect the effect of charged residues on metal binding and protein stability.

Ca2+ controls biological processes by interacting with proteins with different affinities, which are largely influenced by the electrostatic interaction from the local negatively charged ligand residues in the coordination sphere. We have developed a general strategy for rationally designing stable Ca2+- and Ln3+-binding proteins that retain the native folding of the host protein. Domain 1 of cluster differentiation 2 (CD2) is the host for the two designed proteins in this study. We investigate the effect of local charge on Ca2+-binding affinity based on the folding properties and metal-binding affinities of the two proteins that have similarly located Ca2+-binding sites with two shared ligand positions. While mutation and Ca2+ binding do not alter the native structure of the protein, Ca2+ binding specifically induced changes around the designed Ca2+-binding site. The designed protein with a -5 charge at the binding sphere displays a 14-, 20-, and 12-fold increase in the binding affinity for Ca2+, Tb3+, and La3+, respectively, compared to the designed protein with a -3 charge, which suggests that higher local charges are preferred for both Ca2+ and Ln3+ binding. The localized charged residues significantly decrease the thermal stability of the designed protein with a -5 charge, which has a T(m) of 41 degrees C. Wild-type CD2 has a T(m) of 61 degrees C, which is similar to the designed protein with a -3 charge. This decrease is partially restored by Ca2+ binding. The effect on the protein stability is modulated by the environment and the secondary structure locations of the charged mutations. Our study demonstrates the capability and power of protein design in unveiling key determinants to Ca2+-binding affinity without the complexities of the global conformational changes, cooperativity, and multibinding process found in most natural Ca2+-binding proteins.

Construction of a transposon-mediated baculovirus vector Hanpvid and a new cell line for expressing barnase.

In this study we developed the transposon-mediated shuttle vector 'Hanpvid', which composed of HaNPV (Heliothis armigera nuclear polyhedrosis virus) genomic DNA and a transposon cassette from Bacmid of Bac-to-Bac system. Hanpvid replicates in E. coli in the same way as Bacmid and retains infective function in cotton bollworm cells (Hz-AM1). Using Hanpvid we constructed a recombinant virus, which could infect Hz-AM1 cells and generate recombinant HaNPV (rHa-Bar) containing the barnase gene, a ribonuclease gene from Bacillus amyloliquefaciens. Since the expression vector carrying barnase gene cannot replicate in the absence of barstar, a specific inhibitor of barnase, we constructed a new cotton bollworm cell line (AM1-NB) using the marker rescue method. In AM1-NB barstar was integrated into the cellular chromosome to sustain the replication of rHa-Bar. To screen out recombinant HaNPV for potential use as biopesticide, Hz-AM1 and AM1-NB cell lines were infected with rHa-Bar, respectively. The results obtained indicate that Viral progenies in AM1-NB were 23 and 160 times greater than those in Hz-AM1 48 h and 72 h after infection, respectively. With additional insertion of the polyhedron gene from AcNPV (Autographa californica nuclear polyhedrosis virus) into the Hanpvid genome, rHa-Bar regained the polyhedron phenotype and its pest-killing rate greatly improved. Toxic analysis showed that the lethal dosages (LD(50)) and the lethal time(s) (LT(50)) of rHa-Bar were reduced by 20 % and 30 %, respectively, compared to wt-HaNPV in the third instar larvae of cotton bollworm. This study shows that in AM1-NB barnase can be effectively produced and used as pest-killing agent for the biological control of cotton pests.

Design of a calcium-binding protein with desired structure in a cell adhesion molecule.

Ca2+, "a signal of life and death", controls numerous cellular processes through interactions with proteins. An effective approach to understanding the role of Ca2+ is the design of a Ca2+-binding protein with predicted structural and functional properties. To design de novo Ca2+-binding sites in proteins is challenging due to the high coordination numbers and the incorporation of charged ligand residues, in addition to Ca2+-induced conformational change. Here, we demonstrate the successful design of a Ca2+-binding site in the non-Ca2+-binding cell adhesion protein CD2. This designed protein, Ca.CD2, exhibits selectivity for Ca2+ versus other di- and monovalent cations. In addition, La3+ (Kd 5.0 microM) and Tb3+ (Kd 6.6 microM) bind to the designed protein somewhat more tightly than does Ca2+ (Kd 1.4 mM). More interestingly, Ca.CD2 retains the native ability to associate with the natural target molecule. The solution structure reveals that Ca.CD2 binds Ca2+ at the intended site with the designed arrangement, which validates our general strategy for designing de novo Ca2+-binding proteins. The structural information also provides a close view of structural determinants that are necessary for a functional protein to accommodate the metal-binding site. This first success in designing Ca2+-binding proteins with desired structural and functional properties opens a new avenue in unveiling key determinants to Ca2+ binding, the mechanism of Ca2+ signaling, and Ca2+-dependent cell adhesion, while avoiding the complexities of the global conformational changes and cooperativity in natural Ca2+-binding proteins. It also represents a major achievement toward designing functional proteins controlled by Ca2+ binding.