Bacillus cavernae sp. nov. isolated from cave soil.

A Gram-stain-positive, spore-forming, motile, strictly aerobic, rod-shaped bacterium, designated strain L5T, was isolated from soil of Tenglong cave, China. 16S rRNA gene sequence analysis showed that strain L5T was related most closely to Bacillus asahii MA001T (96.5 %) (the highest 16S rRNA gene sequence similarity), Bacillus kribbensis BT080T (96.4 %) and Bacillus deserti ZLD-8T (96.2 %). The DNA G+C content of strain L5T was 45.6 mol%. The major menaquinone was MK-7. The major fatty acids were iso-C14 : 0, anteiso-C15 : 0 and iso-C16 : 0, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. In addition, strain L5T had different characteristics compared with the other Bacillus strains such as pink colony colour, low growth temperature and low nutrient requirement. The results indicate that strain L5T represents a novel species of the genus Bacillus, for which the name Bacillus cavernae sp. nov. is proposed. The type strain is L5T ( = KCTC 33637T = CCTCC AB 2015055T).

Sphingomonas faucium sp. nov., isolated from canyon soil.

A Gram-stain-negative, strictly aerobic, non-motile, yellow, rod-shaped bacterium, designated strain E62-3T, was isolated from soil of Enshi Grand Canyon, Hubei province, PR China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain E62-3T was most closely related to Sphingomonas laterariae LNB2T. Strain E62-3T exhibited the highest 16S rRNA gene sequence similarity to Sphingosinicella vermicomposti YC7378T (96.0 %), Sphingobium xanthum NL9T (95.8 %), Sphingobium boeckii 469T (95.7 %) and Sphingomonas laterariae LNB2T (95.5 %) within the family Sphingomonadaceae. The major fatty acids (>5 %) of strain E62-3T were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and C14 : 0 2-OH. The predominant respiratory quinone and polyamine were ubiquinone Q-10 and homospermidine, respectively. The predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The genomic DNA G+C content was 66.4 mol%. The genotypic, chemotaxonomic and phenotypic data revealed that the isolate represents a novel species of the genus Sphingomonas, for which the name Sphingomonas faucium sp. nov. is proposed. The type strain is E62-3T (=KCTC 42834T=CCTCC AB 2015300T).

[Isolation and characterization of promoter of ADS from Artemisia annua].

OBJECTIVE: To try to find the ways to enhance the expression of ADS gene encoding amorpha-4,11-diene synthase, a key enzyme in artemisinin biosynthesis pathway catalyzing the formation of amorpha-4,11-diene from farnesyl diphosphate, and accelerate the artemisinin synthesis, the promoter of ADS was isolated and characterized. METHOD: 5' untranslated regions of ADS were isolated from Artemisia annua with PCR. For functional characterization, the isolated fragment was fused with GUS reporter gene and introduced into Nicotiana tabacum by Agrobacterium-mediated transformation. The GUS expression regulated by 5' untranslated regions of ADS in transgenic N. tabacum under the normal or stressed conditions were detected by histochemical staining and quantitative spectrophotometry assay. RESULT: The 2 448 bp DNA fragment upstream of ADS coding sequence was isolated from A. annua and introduced into N. tabacum. Histochemical staining showed that the isolated fragment conferred stable GUS expression in transgenic plants. The quantitative results showed that the GUS activity in transgenic tobacco plants treated by low-temperature (4 degrees C) and ultraviolet irradiation were 1. 6 and 2.2 folds higher than that in the controls. CONCLUSION: It was suggested that the isolated fragment had promoter activity and maybe responsive to adverse environmental stresses.

Comamonas testosteroni antA encodes an antimonite-translocating P-type ATPase.

Antimony, like arsenic, is a toxic metalloid widely distributed in the environment. Microbial detoxification of antimony has recently been identified. Here we describe a novel bacterial P1B-type antimonite (Sb(III))-translocating ATPase from the antimony-mining bacterium Comamonas testosterone JL40 that confers resistance to Sb(III). In a comparative proteomics analysis of strain JL40, an operon (ant operon) was up-regulated by Sb(III). The ant operon includes three genes, antR, antC and antA. AntR belongs to the ArsR/SmtB family of metalloregulatory proteins that regulates expression of the ant operon. AntA belongs to the P1B family of the P-type cation-translocating ATPases. It has both similarities to and differences from other members of the P1B-1 subfamily and appears to be the first identified member of a distinct subfamily that we designate P1B-8. Expression AntA in E. coli AW3110 (Δars) conferred resistance to Sb(III) and reduced the intracellular concentration of Sb(III) but not As(III) or other metals. Everted membrane vesicles from cells expressing antA accumulated Sb(III) but not As(III), where uptake in everted vesicles reflects efflux from cells. AntC is a small protein with a potential Sb(III) binding site, and co-expression of AntC with AntA increased resistance to Sb(III). We propose that AntC functions as an Sb(III) chaperone to AntA, augmenting Sb(III) efflux. The identification of a novel Sb(III)-translocating ATPase enhances our understanding of the biogeochemical cycling of environmental antimony by bacteria.

Senescent leaves of Artemisia annua are one of the most active organs for overexpression of artemisinin biosynthesis responsible genes upon burst of singlet oxygen.

To dissect and penetrate complexicity regarding the tissue-specific and environment-induced expression modes of cytosolic and plastidial terpene biosynthetic genes in A. annua, corresponding mRNAs relevant to terpene biosynthesis were quantitatively compared among distinctive organs and during different growth stages. Although all examined mRNAs gradually elevate from June to August in tested organs, a putative artemisinin biosynthesis responsible DBR2 mRNA represents the most abundant transcript anyplace and anytime. Apart from others, senescent leaves endow global activation of artemisinin biosynthetic genes and ultimately lead to enhanced artemisinin production. Direct measurement of (1)O (2) burst from senescent leaves strongly supports an involvement of (1)O (2) in conversion from precursor(s) to artemisinin. In the context of environmental stresses, physical and chemical stress signals that include those invoking (1)O (2) burst were evaluated as if inducing artemisinin biosynthetic genes. The quantitative data have reiterated a common pattern of modulating artemisinin production in A. annua by triggering (1)O (2) burst during senescence and under chilling acclimatization. In conclusion, a missing link concatenating senescence-coupled (1)O (2) generation to (1)O (2)-induced upregulation of artemisinin biosynthetic genes has been re-established, which would provide a fertile base for future endeavors pursuing further enhancements of artemisinin production.

Cloning of artemisinin biosynthetic cDNAs and novel ESTs and quantification of low temperature-induced gene overexpression.

To isolate and verify novel genes from qinghao (Artemisia annua) based on the development-specific and environment-induced transcriptomics, leaves have been harvested from the flowering A. annua plants and exposed to low temperature for isolation of total RNAs and cloning of full-length cDNAs and cDNA fragments, or expressed sequence tags (ESTs). After being sequenced and browsed for homology, these sequences have been submitted to GenBank. Among the accessed 75 sequences, 4 full-length cDNAs are highly homologous to the known A. annua genes, but 71 ESTs are absent in the sequence records of A. annua genes, in which 34 sequences are homologous to other plant genes, including 24 identified protein-coding sequences and 10 unidentified protein-coding sequences, while other 37 sequences are not present in the sequence records of any plant genes, representing the first cloned plant genes. In order to investigate the responsive patterns of A. annua genes to extreme environmental stresses, especially low temperature, the expression levels of 3 critical qinhaosu (artemisinin) biosynthetic genes, ADS, CYP71AV1 and CPR, have been measured in pre-and post-chilling A. annua seedlings cultured in vitro by semi-quantitative PCR (SQ-PCR). Consequently, ADS and CYP71AV1 genes are strongly induced by chilling, but CPR gene is not significantly affected by such treatment. Furthermore, induction of these genes by chilling can be potently suppressed by Ca2+ channel inhibitor LaCl3 or Ca2+ chelator EGTA, suggesting a putative involvement of Ca2+-CaM signal transduction pathway in chilling-induced overexpression of ADS and CYP71AV1 genes. The real-time fluorescent quantitative PCR (RFQ-PCR) assay of A. annua seedlings exposed to chilling has shown that the expression level of CaM gene is up-regulated for more than 2.5 folds, thereby confirming our above inference on the relevance of Ca2+-CaM-mediated signal transduction to chilling-induced gene overexpression. Finally, 7 newly isolated A. annua ESTs have been functionally annotated by RFQ-PCR, which indicates that the chilling stress-induced overexpression levels of D/LTSRP, UBE, AR/DAP and POD1 genes are augmented approximately for 8, 5, 2.3, and 1.5 folds, respectively, but those of CHI and RGP genes are not predominantly up-or down-regulated. The present study has preliminarily explored the chilling-induced overexpression patterns of 3 artemisinin biosynthetic genes and 7 novel A. annua ESTs at the transcriptional level, which should further facilitate our understanding of the intrinsic rule and mechanism underlying the coordinative regulation manner of artemisinin biosynthesis and accumulation, and yield substantial insight into improvement of A. annua by the metabolic engineering-guided breeding strategy.

Mutations outside the YMDD motif in the P protein can also cause DHBV resistant to Lamivudine.

AIM: To observe the Lamivudine resistance character of a DHBV strain in vitro and in vivo, and to analyze if the Lamivudine resistance character is caused by gene mutation or by abnormity of the Lamivudine metabolism. METHODS: Congenitally DHBV-negative Guangdong brown ducks and duck embryo liver cells were respectively taken as animal and cell model. The Lamivudine-susceptive DHBV and Lamivudine-resistant DHBV (LRDHBV) were infected and Lamivudine was administrated according to the divided groups. The changes of DHBV quantity in the animal and cell model were tested. Three Lamivudine-resistant and two Lamivudine-susceptive DHBV complete genomes were successfully amplified, sequenced and then submitted to GenBank. All the DHBV complete sequences in the GenBank at present were taken to align with the three LRDHBV to analyze the mutational points related to the Lamivudine-resistant mutation. RESULTS: Both the animal and cell model showed that the large and the small dosage Lamivudine have no significant inhibitory effect on the LRDHBV. Five sequences of DHBV complete genomes were successfully cloned. The GenBank accession numbers of the three sequences of LRDHBV are AY521226, AY521227, and AY433937. The two strains of Lamivudine-susceptive DHBV are AY392760 and AY536371. The correlated mutational points are KorR86Q and AorE591T in the P protein. CONCLUSION: The Lamivudine resistance character of this DHBV strain is caused by genome mutation; the related mutational points are KorR86Q and AorE591T and have no relations with the YMDD motif mutation.

Quantitative transcript profiling reveals down-regulation of A sterol pathway relevant gene and overexpression of artemisinin biogenetic genes in transgenic Artemisia annua plants.

To investigate the dynamic fluctuation of terpenoid relevant transcriptomics in transgenic ARTEMISIA ANNUA plants that express the genomic integrated antisense squalene synthase gene ( ASSS), we have quantified the transcript levels of the sterol anabolic SS gene as well as artemisinin biogenetic amorphadiene synthase (ADS), cytochrome P450 monooxygenase (CYP71AV1) and cytochrome P450 reductase (CPR) genes by real-time fluorescent quantitative polymerase chain reaction (RFQ-PCR). The SS mRNA level in transgenic plants sharply droped to 7.4 % - 55.3 % (i. e., 44.7 - 92.6 % reduction as the wild-type control), strongly implying that the expression of endogenous SS gene is significantly suppressed by the exogenous ASSS gene. In a synchronous fashion, ADS, CYP71AV1 and CPR mRNA levels elevated with the decline of SS mRNA level in transgenic plants, and the maximal ADS, CYP71AV1 and CPR mRNA levels in transgenic plants were 3.0-, 4.4- and 2.5-fold, respectively, higher than those in the control. Without a lethal effect but with a distinguishable impact on the organogenesis and morphology of transgenic plants, the down-regulation of SS gene has also led to the coordinated overexpression of ADS, CYP71AV1 and CPR genes together with the overproduction of artemisinin although no fully perfect correlation among the available experimental data has been shown.

[Cloning, soluble expression and mutant activity analysis of lactate dehydrogenase gene from Plasmodium falciparum].

To establish a platform for high throughput screening and in vitro evaluating novel metabolic enzyme-targeted inhibitors towards anti-malarial drugs, a lactate dehydrogenase gene of Plasmodium falciparum (PfLDH) was amplified from the Hainan isolate FCC1/HN. The fusion expression vectors, pGEX-2TK and pET-29a( + ), were utilized to introduce the PfLDH gene into strains of Escherichia coli, BL21 and BL21 (DE3), for over-expression. Consequently, the enzymatic activity of PfLDH was successfully detected in the suspension of lytic bacteria. The PfLDH gene cloned in pGEX-2TK was mainly expressed as inclusion bodies, while the same gene cloned in pET-29a( + ) was nearly expressed in a soluble form of PfLDH, demonstrating the latter vehicle might be more suitable for the large-scale preparation of recombinant PfLDH. Furthermore, according to the electrophoregram of SDS-PAGE and the sequencing data, a series of truncated PfLDH sequences generated randomly from gene amplification were screened and cloned, from which four pre-matured genes with a terminator mutation, PfLDH-delta271, -delta236, -delta167 and -delta53 coding for 45, 80, 149 and 263 amino acid residues, were individually recovered. Through the gene expression and enzymatic activity measurement, the effect of pre-matured terminator mutation on the activity of PfLDH was evaluated, which should pave the way for probing the relationship between structure and function of PfLDH.

[Establishment of stably expressed human RANTES gene in prunella vulgaris cell clone].

To express interesting human genes in herbal cells for boosting their specific pharmacological activities, RANTES gene cloned from human peripheral blood lymphocyte (PBL) mRNA was introduced into A. tumefaciens strain LBA4404 harboring pAL4404 plasmid via tumor-inducing (Ti) plasmid-derived intermediate expression vector pROKII. In vitro cultured P. vulgaris cells were transformed by leaf-disk cocultivation procedure. Integration of RANTES gene in the genome of transformed cells was confirmed by Southern blotting, and expression of RANTES gene in transformed cells was analyzed by RT-PCR amplification, Western blotting and enzyme-linked immunosorbent assay (ELISA). The peroxidase activity of PBL was utilized as a detection index of cellular chemotropism induction by recombinant RANTES. The results have shown the RANTES gene was integrated in transgenic P. vulgaris cells, and RANTES gene-stably expressed cell clones were available, which could pave the way to obtain transgenic P. vulgaris plants demonstrating specific pharmacological activities.