Mutagenesis Reveals That the OsPPa6 Gene Is Required for Enhancing the Alkaline Tolerance in Rice.

Alkaline stress (AS) is one of the abiotic stressful factors limiting plant's growth and development. Inorganic pyrophosphatase is usually involved in a variety of biological processes in plant in response to the abiotic stresses. Here, to clarify the responsive regulation of inorganic pyrophosphatase in rice under AS, the mutagenesis of the OsPPa6 gene encoding an inorganic pyrophosphatase in rice cv. Kitaake (Oryza sativa L. ssp. japonica) was performed by the CRISPR/Cas9 system. Two homozygous independent mutants with cas9-free were obtained by continuously screening. qPCR reveals that the OsPPa6 gene was significantly induced by AS, and the mutagenesis of the OsPPa6 gene apparently delayed rice's growth and development, especially under AS. Measurements demonstrate that the contents of pyrophosphate in the mutants were higher than those in the wild type under AS, however, the accumulation of inorganic phosphate, ATP, chlorophyll, sucrose, and starch in the mutants were decreased significantly, and the mutagenesis of the OsPPa6 gene remarkably lowered the net photosynthetic rate of rice mutants, thus reducing the contents of soluble sugar and proline, but remarkably increasing MDA, osmotic potentials and Na+/K+ ratio in the mutants under AS. Metabonomics measurement shows that the mutants obviously down-regulated the accumulation of phosphorylcholine, choline, anthranilic acid, apigenin, coniferol and dodecanoic acid, but up-regulated the accumulation of L-valine, alpha-ketoglutarate, phenylpyruvate and L-phenylalanine under AS. This study suggests that the OsPPa6 gene is an important osmotic regulatory factor in rice, and the gene-editing of CRISPR/Cas9-guided is an effective method evaluating the responsive regulation of the stress-induced gene, and simultaneously provides a scientific support for the application of the gene encoding a soluble inorganic pyrophosphatase in molecular breeding.

Monoclonal antibodies directed against VP7 protein of human group B rotavirus.

The aim of this study was to prepare and identify a monoclonal antibody that binds the viral proteins 7 (VP7 protein) of human group B rotavirus (GBRV) and to describe its immunologic characterization. Human group B rotavirus vp7 gene was successfully ligated into pGEX-KG vector and transformed into Escherichia coli TOP10 cells. The glutathione S-transferases (GST)-fusion protein GST-VP7 was induced by Isopropyl ß-D-1-thiogalactopyranoside (IPTG) and immediately purified to immunize BALB/c mice. Splenocytes were then prepared from the immunized mouse and fused with SP2/0 myeloma cell line. In the end we obtained one positive hybridoma cell line stably secreting monoclonal antibody against GST-VP7 protein by indirect enzyme-linked immunosorbent assay (ELISA) and limiting dilution. The production of the monoclonal antibody against GBRV will benefit the further study of GBRV's structures and functions and also lay a solid foundation for the research of disease prevention, clinical diagnosis, and treatment.

Development of neutralizing monoclonal antibodies against VP4 of rotavirus CC0812-1.

The G10P[15] rotavirus CC0812-1 isolated from a diarrheal woman in Wuhan, China, in 2008 is phylogenetically close to the Lanzhou lamb rotavirus (LLR) of a monovalent human rotavirus vaccine produced by the Lanzhou Institute of Biological Products, China, and rotavirus Lamb-NT. This rotavirus can be used as the backbone of the attenuated rotavirus reassortant as a rotavirus vaccine candidate. In this study, rotavirus CC0812-1 was purified from the culture supernatant of CC0812-1-infected MA104 cells and used as antigen to immunize BALB/c mice. Four hybridoma clones were developed secreting antibodies that reacted with CC0812-1, designated as 1B1, 1B8, 1F11, and 1G10, respectively. Western blot analysis indicated that the four monoclonal antibodies (MAbs) were all specific for VP4 of rotavirus CC0812-1. Isotyping revealed that MAbs 1B1, 1B8, and 1G10 belonged to the IgM class, while MAb 1F11 belonged to the IgG1 subclass. A neutralization test demonstrated that the four MAbs all had the capacity to neutralize rotavirus CC0812-1. The neutralizing titers of the BALB/c mice ascites were 1:2048, 1:1024, 1:512, and 1:512 for MAbs 1B1, 1B8, 1F11, and 1G10, respectively.

Identification of Sare0718 as an alanine-activating adenylation domain in marine actinomycete Salinispora arenicola CNS-205.

BACKGROUND: Amino acid adenylation domains (A domains) are critical enzymes that dictate the identity of the amino acid building blocks to be incorporated during nonribosomal peptide (NRP) biosynthesis. NRPs represent a large group of valuable natural products that are widely applied in medicine, agriculture, and biochemical research. Salinispora arenicola CNS-205 is a representative strain of the first discovered obligate marine actinomycete genus, whose genome harbors a large number of cryptic secondary metabolite gene clusters. METHODOLOGY/PRINCIPAL FINDINGS: In order to investigate cryptic NRP-related metabolites in S. arenicola CNS-205, we cloned and identified the putative gene sare0718 annotated "amino acid adenylation domain". Firstly, the general features and possible functions of sare0718 were predicted by bioinformatics analysis, which suggested that Sare0718 is a soluble protein with an AMP-binding domain contained in the sequence and its cognate substrate is L-Val. Then, a GST-tagged fusion protein was expressed and purified to further explore the exact adenylation activity of Sare0718 in vitro. By a newly mentioned nonradioactive malachite green colorimetric assay, we found that L-Ala but not L-Val is the actual activated amino acid substrate and the basic kinetic parameters of Sare0718 for it are K(m) = 0.1164±0.0159 (mM), V(max) = 3.1484±0.1278 (µM/min), k(cat) = 12.5936±0.5112 (min(-1)). CONCLUSIONS/SIGNIFICANCE: By revealing the biochemical role of sare0718 gene, we identified an alanine-activating adenylation domain in marine actinomycete Salinispora arenicola CNS-205, which would provide useful information for next isolation and function elucidation of the whole cryptic nonribosomal peptide synthetase (NRPS)-related gene cluster covering Sare0718. And meanwhile, this work also enriched the biochemical data of A domain substrate specificity in newly discovered marine actinomycete NRPS system, which bioinformatics prediction will largely depend on.

Monoclonal antibodies directed against Fpr3 protein as molecular chaperones.

Fpr3 is the third member of the FKBP (FK506 binding protein) family in yeast. In this study, the fpr3 gene from Saccharomyces cerevisiae was overexpressed and the protein product was purified using different methods. The recombinant Fpr3 fusion protein (rFpr3) was then used as antigen to immunize BALB/c mice for the production of monoclonal antibodies (MAb). Western blot and ELISA results indicated that rFpr3 had specific binding ability to the MAbs, and isotyping results classified the MAb as the subclass IgG1 by antibody. The MAbs obtained in this study will be used as a molecular chaperone to obtain Fpr3 crystals.

Crystal structure of the Cys2His2-type zinc finger domain of human DPF2.

DPF2 is an evolutionary highly conserved member of the d4-protein family characterized by an N-terminal 2/3 domain, a C2H2-type zinc finger (ZF), and a C-terminal tandem PHD zinc finger. DPF2 is identified as a transcription factor and may be related with some cancers in human. Here, we report the crystal structure of the C2H2-type zinc finger domain of human DPF2 with a canonical C2H2 fold, which contains two beta strands and one alpha helix. Several conserved residues, including Lys207, Lys216 and Arg217, constitute a positively charged surface in C2H2 domain, which implicates that it has the potential to bind DNA. The side chains of the residues Y209, C211, C214, K216, Y218, L224, H227 and H232 form the hydrophobic core of C2H2 domain, which indicates a potential-binding surface in the human DPF2.

Crystal structure of the mismatch-specific thymine glycosylase domain of human methyl-CpG-binding protein MBD4.

Methyl-CpG (mCpG) binding domain protein 4 (MBD4) is a member of mammalian DNA glycosylase superfamily. It contains an amino-proximal methyl-CpG binding domain (MBD) and a C-terminal mismatch-specific glycosylase domain, which is an important molecule believed to be involved in maintaining of genome stability. Herein, we determined the crystal structure of C-terminal glycosylase domain of human MBD4. And the structural alignments of other helix-hairpin-helix (HhH) DNA glycosylases show that the human MBD4 glycosylase domain has the similar active site and the catalytic mechanisms as others. But the different residues in the N-terminal of domain result in the change of charge distribution on the surface of the protein, which suggest the different roles that may relate some diseases.

[A molecular phylogeny of Shennongjia white bear based on mitochondrial cytochrome b gene sequence].

The phylogenetic relationship of Shennongjia white bear has been an open question. Total DNA was extracted and sequenced from hair and feces of Shennongjia white bear. Based on the partial Cyt b gene sequence obtained from the samples, the authors aligned them using the Clustal W software program. The MEGA software was used to analyze the divergences and base substitutions of the partial Cyt b gene among the 11 species: Shennongjia white bear, Selenarctos thibetanus, Euarctos americanus, Helarctos malayanus, Ursus arctos, Thalarctos maritimus, Melursus ursinus, Procyon lotor, Ailuropoda melanoleuca, Ailurus fulgens and Tremarctos ornatus. The phylogenetic trees constructed by multiple methods (NJ and MP) supported nearly the same topology. Our molecular results show that the sequence divergence between Shennongjia white bear and Asiatic black bear (Selenarctos thibetanus) is lower than that between other species.

[Whole sequence analysis of brain-derived neurotrophic factor gene in Asiatic Black Bear through faecal sampling].

Using our lab's improved protocol for faecal DNA extraction, the entire 753-bp DNA coding sequence of the nuclear brain-derived neurotrophic factor (BDNF) gene was cloned for the first time from Asiatic Black Bear Selenarctos thibetanus faecal samples with primers based on the reported sequence of the Malayan Bear BDNF gene. Hair was used as a positive control and the experiments were repeated several times to obtain reliable and identical results. Sequence analysis showed that the BDNF gene of Asiatic Black Bear was highly conserved compared to those of human and giant panda, with an identity of 94.5% and 98.9%, respectively. The deduced amino acid sequence of the mature protein was found to be identical to those of all the reported mammalians. According to gene sequence alignment, the giant panda appeared to be phylogenetically closer to Asiatic Black Bear than the lesser panda. This study represents the first time that a non-invasive method such as faecal sampling was used to analyze a functional nuclear BDNF gene of Asiatic Black Bear. It will not only provide important reference for the conservation and breeding of Asiatic Black Bear and open up new avenues of non-invasive sampling in the study of endangered wildlife, but also provide another molecular evidence for the study of relationship of Asiatic Black Bear and its related species.