Tropical Bioscience and Biotechnology Research Institute

Covering: Up to the end of 2019.Agarwood is a resinous portion of Aquilaria trees, which is formed in response to environmental stress factors such as physical injury or microbial attack. It is very sought-after among the natural incenses, as well as for its medicinal properties in traditional Chinese and Ayurvedic medicine. Interestingly, the chemical constituents of agarwood and healthy Aquilaria trees are quite different. Sesquiterpenes and 2-(2-phenethyl)chromones with diverse scaffolds commonly accumulate in agarwood. Similar structures have rarely been reported from the original trees that mainly contain flavonoids, benzophenones, xanthones, lignans, simple phenolic compounds, megastigmanes, diterpenoids, triterpenoids, steroids, alkaloids, etc. This review summarizes the chemical constituents and biological activities both in agarwood and Aquilaria trees, and their biosynthesis is discussed in order to give a comprehensive overview of the research progress on agarwood.

Summary Plants have served as sources providing humans with metabolites for food and nutrition, biomaterials for living, and treatment for pain and disease. Plants produce a huge array of metabolites, with an immense diversity at both the population and individual levels. Dissection of the genetic bases for metabolic diversity has attracted increasing research attention. The concept of genome‐wide association study ( GWAS ) was extended to studies on the diversity of plant metabolome that benefitted from the development of mass‐spectrometry‐based analytical systems and genome sequencing technologies. Metabolic genome‐wide association study ( mGWAS ) is one of the most powerful tools for global identification of genetic determinants for diversity of plant metabolism. Recently, mGWAS has been performed for various species with continuous improvements, providing deeper insights into the genetic bases of metabolic diversity. In this review, we discuss fully the achievements to date and remaining challenges that are associated with both mGWAS and mGWAS ‐based multi‐dimensional analysis. We begin with a summary of GWAS and its development based on statistical methods and populations. As variation in targeted traits is essential for GWAS , we review metabolic diversity and its rise at both the population and individual levels. Subsequently, the application of mGWAS for plants and its corresponding achievements are fully discussed. We address the current knowledge on mGWAS ‐based multi‐dimensional analysis and emerging insights into the diversity of metabolism.

The chloroplast-localized SIB1 protein was previously identified by its interaction with SIGMA FACTOR 1 (SIG1), a component of the RNA polymerase machinery responsible for transcription of plastid genes. The physiological function of SIB1 is little known. We found that expression of SIB1 is induced by infection with Pseudomonas syringae, suggesting its possible involvement in the defence response. The sib1 loss-of-function mutation compromises induction of some defence-related genes triggered by pathogen infection and the treatments with salicylic acid (SA) and jasmonic acid (JA), two key signalling molecules in the defence response. Conversely, constitutive over-expression of SIB1 causes the plants to hyper-activate defence-related genes following pathogen infection or the SA and JA treatments, leading to enhanced resistance to infection by P. syringae. SIB1 is a member of the large plant-specific VQ motif-containing protein family, and might act as a link to connect defence signalling with chloroplast function.

Recently, oncolytic virus (OV) therapy has shown great promise in treating malignancies. However, intravenous safety and inherent lack of immunity are two significant limitations in clinical practice. Herein, we successfully developed a recombinant Newcastle disease virus with porcine α1,3GT gene (NDV-GT) triggering hyperacute rejection. We demonstrated its feasibility in preclinical studies. The intravenous NDV-GT showed superior ability to eradicate tumor cells in our innovative CRISPR-mediated primary hepatocellular carcinoma monkeys. Importantly, the interventional clinical trial treating 20 patients with relapsed/refractory metastatic cancer (Chinese Clinical Trial Registry of WHO, ChiCTR2000031980) showed a high rate (90.00%) of disease control and durable responses, without serious adverse events and clinically functional neutralizing antibodies, further suggesting that immunogenicity is minimal under these conditions and demonstrating the feasibility of NDV-GT for immunovirotherapy. Collectively, our results demonstrate the high safety and efficacy of intravenous NDV-GT, thus providing an innovative technology for OV therapy in oncological therapeutics and beyond.

A new surfactin isomer (1) was isolated from a mangrove bacteria strain 'Bacillus sp'. Its structure was identified, and full assignments of (1)H and (13)C NMR spectral data were achieved for the first time by a combination of mass spectrometry and 1D and 2D NMR experiments including DEPT, (1)H-(1)H COSY, HSQC, HMBC, TOCSY, ROESY, and HSQC-TOCSY. The NMR spectral data of eight known analogs (2-9) are also reported.

Fusarium wilt of banana, which is caused by Fusarium oxysporum f. sp. cubense, is one of the most serious diseases of banana. F. oxysporum f. sp. cubense race 1 (Foc1) and race 4 (Foc4) are the most prevalent pathogens of banana cultivars in the world. To understand the differences in the infection processes between Foc1 and Foc4, green fluorescent protein-tagged strains of F. oxysporum f. sp. cubense tropical race 4 (FocTR4) and Foc1 were used to inoculate 'Brazil Cavendish' banana. At 2 days postinoculation (dpi), it was observed that the spores and hyphae of both Foc1 and Foc4 attached to the root hairs and root epidermis. At 3 dpi, the hyphae of both Foc1 and Foc4 were found in the vascular tissues of roots. However, Foc4 was observed in the parenchymal cells of banana root, whereas Foc1 was not found in parenchymal cells at 7 dpi. Furthermore, few Foc1 hyphae were observed in a few xylems whereas many more Foc4 hyphae were present in many xylems and phloems. Foc4 was observed in the vascular tissues of banana rhizomes, whereas no Foc1 was found in rhizomes 2 months after inoculation. The attachment process in F. oxysporum f. sp. cubense infection was further studied with scanning electron microscopy. Foc4 was observed to penetrate into banana roots from the intercellular space of the epidermis and wounds, whereas Foc1 mainly penetrated from the wounds but not from the intercellular space of the epidermis. Therefore, direct root penetration and rhizome vascular colonization by F. oxysporum f. sp. cubense are the key steps in the successful infection of Brazil Cavendish.

Rice bacterial blight (BB) is a devastating rice disease. The Xa21 gene confers a broad and persistent resistance against BB. We introduced Xa21 into Oryza sativa L ssp indica (rice 9311), through multi-generation backcrossing, and generated a nearly isogenic, blight-resistant 9311/Xa21 rice. Using next-generation sequencing, we profiled the transcriptomes of both varieties before and within four days after infection of bacterium Xanthomonas oryzae pv. oryzae. The identified differentially expressed (DE) genes and signaling pathways revealed insights into the functions of Xa21. Surprisingly, before infection 1,889 genes on 135 of the 316 signaling pathways were DE between the 9311/Xa21 and 9311 plants. These Xa21-mediated basal pathways included mainly those related to the basic material and energy metabolisms and many related to phytohormones such as cytokinin, suggesting that Xa21 triggered redistribution of energy, phytohormones and resources among essential cellular activities before invasion. Counter-intuitively, after infection, the DE genes between the two plants were only one third of that before the infection; other than a few stress-related pathways, the affected pathways after infection constituted a small subset of the Xa21-mediated basal pathways. These results suggested that Xa21 primed critically important genes and signaling pathways, enhancing its resistance against bacterial infection.

Six new prenylated hydroquinones of ganocalidin A–F (<bold>1–6</bold>) and two new compounds of ganocalicine A (<bold>7</bold>) and B (<bold>8</bold>), together with sixteen known compounds (<bold>9–24</bold>) were isolated from an extract of the fruiting body of <italic>Ganoderma calidophilum</italic>.

Abstract The polyhydroxylated ergostane‐type sterol 9 , its derivatives 10 – 15 , and the fatty acid esters 1 – 8 were isolated from a fungus strain which was collected from mangrove areas at Wenchang, Hainan Province, P. R. China, exhibited potent cytotoxic activity, and was identified as Aspergillus awamori. The structures of 1 – 15 were elucidated by spectroscopic and chemical methods. Among them, the six steryl esters 1 – 6 of fatty acids were new compounds, i.e. , (3 β ,5 α ,6 α ,22 E )‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐palmitate ( 1 ), (3 β ,5 α ,6 α ,22 E )‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐stearate ( 2 ), (3 β ,5 α ,6 α ,22 E )‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐oleate ( 3 ), (3 β ,5 α ,6 α ,22 E )‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐linoleate ( 4 ), (3 β ,5 α ,6 β ,22 E )‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐palmitate ( 5 ), and (3 β ,5 α ,6 β ,22 E )‐ergosta‐7,22‐diene‐3,5,6‐triol 6‐stearate ( 6 ). The related known fatty acids stearic acid (=octadecanoic acid) and palmitic acid (=octadecanoic acid) were also obtained. A speculative biogenetic relationship of the metabolites is proposed. The known polyhydroxylated sterols and derivatives showed cytotoxic activities, in agreement with earlier reports. The cytotoxic activities against B16 and SMMC‐7721 cell lines of the new steryl esters 1 – 6 by the MTT method were weak.

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory disease that comprises ulcerative colitis (UC) and Crohn's disease (CD). IBD involves the ileum, rectum, and colon, and common clinical manifestations of IBD are diarrhea, abdominal pain, and even bloody stools. Currently, non-steroidal anti-inflammatory drugs, glucocorticoids, and immunosuppressive agents are used for the treatment of IBD, while their clinical application is severely limited due to unwanted side effects. Chinese medicine (CM) is appealing more and more attention and investigation for the treatment of IBD owing to the potent anti-inflammation pharmacological efficacy and high acceptance by patients. In recent years, novel drug delivery systems are introduced apace to encapsulate CM and many CM-derived active constituents in order to improve solubility, stability and targeting ability. In this review, advanced drug delivery systems developed in the past and present to deliver CM for the treatment of IBD are summarized and future directions are discussed.

Two new oxidized sterols 1 and 2 were obtained from the active fraction of a mangrove fungus Aspergillus awamori isolated from the soils around the mangrove plant Acrostichum speciosum. Their structures were elucidated using spectroscopic methods as 22E-7alpha-methoxy-5alpha,6alpha-epoxyergosta-8(14),22-dien-3beta-ol (1) and 22E-3beta-hydroxy-5alpha,6alpha,8alpha,14alpha-diepoxyergosta-22-en-7-one (2). The NMR data and complete assignments for both DMSO-d(6) and CDCl(3) were given. Their cytotoxic activity against A549 cell line was evaluated. Furthermore, the detailed conformation analysis for ring B (cyclohexene oxide system) of sterol 1 was given on the basis of NOEs. The endo-boat conformation was considered as the preferred conformation for ring B rather than half-chair conformation.

Duckweed species have a great potential to develop into fast-growing crops for water remediation and bioenergy production. Seed production and utilization of hybrid vigour are essential steps in this process. However, even in the extensively-studied duckweed species, Lemna gibba, flower primordia were often aborted prior to maturation. Salicylic acid (SA) and agar solidification of the medium promoted flower maturation and resulted in high flowering rates in L. gibba 7741 and 5504. Artificial cross-pollination between individuals of L. gibba 7741 yielded seeds at high frequencies unlike that in L. gibba 5504. In contrast to clone 7741, the anthers of 5504 did not dehisce upon maturation, its artificially released pollen grains had pineapple-like exine with tilted spines. These pollens were not stained by 2,5-diphenylmonotetrazoliumbromide (MTT) and failed to germinate. Therefore, clone 5504 is male sterile and has potential application with respect to hybrid vigour. Moreover, pollination of flowers of 5504 with 7741 pollen grains resulted in intraspecific hybrid seeds, which was confirmed by inter-simple sequence repeat (ISSR) markers. These hybrid seeds germinated at a high frequency, forming new clones.

A high-density cell culture method to produce human angiostatin has been successfully established by constitutive expression of the protein in Pichia pastoris. The fermentation was carried out in a 20 l bioreactor with a 10 l working volume, using a high-density cell culture method by continuously feeding with 50% glycerol-0.8% PTM4 to the growing culture for 60 h at 30 degrees C. Dissolved oxygen level was maintained at 25-30% and pH was controlled at 5 by the addition of 7 M NH4OH. Angiostatin was constitutively expressed during the fermentation by linking its expression to the P. pastoris constitutive GAP promoter (pGAP). But after 36 h of fermentation, the peak biomass growth was 305 as measured by absorption of 600 nm, while the peak angiostatin expression was 176 mg/l. Similar to the product expressed from inducible system [24], angiostatin produced from constitutive system also inhibited the angiogenesis on the CAM and suppressed the growth of B16 melanoma in C57BL/6J mouse. The above results suggest that GAP promoter is more efficient than AOX1 promoter for the expression of angiostatin in P. pastoris by shake flask culture or high-density cell fermentation and is likely to be an alternative to AOX1 promoter in large-scale expression of angiostatin and other heterologous proteins.

A mark-release-recapture experiment was conducted in a small isolated village on Hainan Island, China, to examine the dispersal and movement of adult Aedes aegypti (L.). Two cohorts of mosquitoes marked with uniquely colored fluorescent dye were released at two different sites and recaptured for 6 d at every house in the village using human bait collections. The distribution pattern of houses around release site affected dispersal. The recapture rate of females released at the center of the village was higher (3.49%) than females released at the edge of the village (2.47%). The average day of recapture differed significantly between sexes, but not cohorts. The average day of recapture of females and males released at the center was 2.5 and 1.54 d, respectively. The total number of mosquitoes recaptured was the greatest at premises near the release site, and decreased at a constant rate of 0.43-0.48 with increasing distance from the release site. The proportion of nulliparous females decreased during the first 4 d and proportion of females with developing or mature ovaries increased during the latter half of the experiment. The daily survival rate for females and males released at the center of the village was estimated by log-regression to be 0.763 and 0.52, respectively.

This study demonstrated the protective effects of noni fruit and its fermented juice with different fermentation times against the acute liver injury caused by alcohol. In vitro trials were conducted to assess the antioxidant activities of noni fruit and fermented juice, while protective effects were confirmed by in vivo trials using mice model. The results showed that fresh noni fruit had higher antioxidant capacities (1,1-diphenyl-2-picrylhydrazyl scavenging activity, hydroxyl-radical scavenging ability, and reducing power) than fermented noni juice. However, in vivo experiments demonstrated that fermented noni juice had a comprehensive preventive effect on acute alcohol-induced liver injury, based on the histopathological analysis and the measurements of markers of serum and liver. The markers include aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, high density lipoprotein cholesterol, low density lipoprotein cholesterol, total cholesterol, and triglyceride. This study provides positive insights into the potential role of noni fruit and fermented juice in combating challenges presented by alcohol consumption and highlights the potential of noni fruit as functional food.

Abstract Salt stress is a major environmental threat to meeting the food demands of an increasing global population. The identification and exploitation of salt adaption mechanisms in plants are therefore vital for crop breeding. We here define the rice mutant ( sstm1 ) whose salt sensitivity was unambiguously assigned to a single T‐DNA insertion through segregational analysis following backcrossing to the wild type line. Insertion was within OsTSD2 , which encoded a pectin methyltransferase. The sstm1 and allelic mutants, collectively known as tsd2 , displayed higher content of Na + and lower level of K + in the shoot, which is likely to lead to reduced salt tolerance. Molecular analysis revealed reduced expression of the genes maintaining K + /Na + homeostasis in tsd2 , including OsHKT1;5 , OsSOS1 , and OsKAT1 . Furthermore, OsTSD2 influenced ion distribution between the hull and the rice seed, which could improve food safety with heavy metal pollution. Amino acid levels tended to be increased in tsd2 mutants, implicating a role of pectin in the regulation of metabolism. Taken together, we have demonstrated an important facet of salt tolerance, which implicated OsTSD2 ‐mediated cell wall pectin modification as a key component that could be widely applied in crop science.

A four-week feeding trial, followed by a challenge test, was conducted to evaluate the effects of Lactococcus lactis and astaxanthin on the growth performance, digestive ability, antioxidant capacity, immunity, and disease resistance of Litopenaeus vannamei against Vibrio alginolyticus. Specifically, shrimp were randomly allocated into 12 tanks (100 shrimp per tank), and divided into 4 groups with 3 replicates. Shrimp were fed on either a control (CK) or three other treatment diets by supplementing L. lactis at 1 × 108 CFU g−1 diet (L), astaxanthin at 250 mg kg−1 diet (A) and L. lactis at 1 × 108 CFU g−1 diet combined with astaxanthin 250 mg kg−1 diet (LA). Results indicated that treatment diets significantly improved growth performance and increased the activity of digestive enzymes relative to the control diet. Particularly, the highest parameters were recorded in shrimp fed on astaxanthin alone. Moreover, statistical analysis revealed significant differences in antioxidant and immune enzymes activities between shrimp in the CK and A groups. From the results of the challenge test, shrimp fed on treatment diets all had significantly lower mortality as compared to the control diet, and shrimp fed on astaxanthin alone had the lowest mortality. Dietary supplementation of astaxanthin alone significantly increased the relative expression of Cru, Pen-3α, SOD and LZM and decreased the relative expression of proPO in the gut of shrimp as compared to the control diet. The results indicates that the relative expression levels of most selected immune-related genes were significantly up-regulated in shrimp fed on astaxanthin alone, which may explain the best disease resistance observed in this group. Taken together, the findings of this study suggest that astaxanthin can positively affect the growth performance, digestive ability, antioxidant capacity, immunity, and disease resistance of L. vannamei against V. alginolyticus. Notably, these effects are superior to those induced by L. lactis alone or in combination with L. lactis.

Laticifers are highly specialized cells that synthesize and store natural rubber. Rubber trees (Hevea brasiliensis Muell. Arg.) contain both primary and secondary laticifers. Morphological and functional differences between the two types of laticifers are largely unknown, but such information is important for breeding and cultivation practices. Morphological comparison using paraffin sections revealed only distribution differences: the primary laticifers were distributed randomly, while the secondary laticifers were distributed in concentric rings. Using isolated laticifer networks, the primary laticifers were shown to develop via intrusive "budding" and formed necklace-like morphology, while the secondary laticifers developed straight and smooth cell walls. Comparative transcriptome analysis indicated that genes involved in cell wall modification, such as pectin esterase, lignin metabolic enzymes, and expansins, were highly up-regulated in the primary laticifers and correspond to its necklace-like morphology. Genes involved in defense against biotic stresses and rubber biosynthesis were highly up-regulated in the primary laticifers, whereas genes involved in abiotic stresses and dormancy were up-regulated in the secondary laticifers, suggesting that the primary laticifers are more adequately prepared to defend against biotic stresses, while the secondary laticifers are more adequately prepared to defend against abiotic stresses. Therefore, the two types of laticifers are morphologically and functionally distinct.

The red tide in Hongsha Bay caused by Skeletonema costatum (S. costatum) from April 27 to May 4, 2006, was monitored in this study. The dynamic variety of environmental factors, including chlorophyll a (chl a), temperature, salinity, pH, dissolved oxygen, chemical oxygen demand, nitrate, ammonium, nitrite, phosphate (PO43−), silicate, and iron (Fe), was observed and analyzed during the red tide in Hongsha Bay for the first time. The results indicated that the concentration of dissolved inorganic nitrogen was high (26.34 μmol/L) in Hongsha Bay. Because of the heavy rainfall from April 13 to 15, a large input of nutrients surged into the bay, causing an increase in the concentration of various nutrients, especially PO43−, which showed an obvious increase (from 0.72 to 1.45 μmol/L). The abundant nutrients provided fundamental nutrient supply for the rapid proliferation of S. costatum. Three critical environmental factors, including water temperature, and PO43− and Fe concentration, played an important role in this red tide. Water temperature had a significant positive correlation with chl a. The water temperature shift was one of the critical environmental factors affecting the S. costatum red tide in Hongsha Bay. With the occurrence of the red tide, the concentration of PO43− rapidly decreased. Inorganic PO43− was rapidly depleted at the blooming stage, causing the red tide to gradually dissipate. Phosphate was the limiting factor of S. costatum proliferation in this red tide. Iron was also a factor. Salinity shift had little effect on the growth of S. costatum.

A 6-week growth trial was conducted to evaluate the influences of dietary valine (Val) levels on growth, protein utilisation, immunity, antioxidant status and gut micromorphology of juvenile hybrid groupers. Seven isoenergetic, isoproteic and isolipidic diets were formulated to contain graded Val levels (1·21, 1·32, 1·45, 1·58, 1·69, 1·82 and 1·94 %, DM basis). Each experimental diet was hand-fed to triplicate groups of twelve hybrid grouper juveniles. Results showed that weight gain percentage (WG%), protein productive value, protein efficiency ratio, and feed efficiency were increased as dietary Val level increased, reaching a peak value at 1·58 % dietary Val. The quadratic regression analysis of WG% against dietary Val levels indicated that the optimum dietary Val requirement for hybrid groupers was estimated to be 1·56 %. Gut micromorphology and expression of growth hormone in pituitary, insulin-like growth factor 1, target of rapamycin and S6 kinase 1 in liver were significantly affected by dietary Val levels. In serum, fish fed 1·58 % dietary Val had higher superoxide dismutase, catalase, lysozyme activities and IgM concentrations than fish fed other dietary Val levels. Fish fed 1·58 % dietary Val had higher expression of NF-E2-related factor 2 in head kidney than fish fed other dietary Val levels. Generally, the optimum dietary Val requirement for maximal growth of hybrid groupers was estimated to be 1·56 % of DM, corresponding to 3·16 % of dietary protein, and dietary Val levels affected growth, protein utilisation, immunity and antioxidant status in hybrid groupers.