Biotechnology Research and Innovation最新文献

In order to meet global food security demands in the next decades, considerable changes are required for sustainable agriculture in the context of plant disease, with sufficient food production depending on the development of durable genetically disease resistant crops. For this, further advances are required in our understanding of the plant innate immune system and how plants respond to invading pathogenic micro-organisms. Over the past 20 years, considerable research has been conducted into the characterization and cloning of plant nucleotide-binding, leucine-rich repeat (NLR) immune receptors. These intracellular receptors can recognize directly or indirectly pathogen effector proteins, resulting in effector-triggered immunity (ETI). Elucidation, however, of the diversity of NLR resistance gene families and the molecular basis of NLR-driven effector recognition and defense signaling is incomplete. Here, we present a summary of the understanding of NLR structure, function, genomic organization and diversity in plants. Recent advances in target enrichment approaches for NLR characterization and function validation are highlighted in the context of NLR engineering possibilities for accelerated durable genetic resistance to biotic stresses.

Integrative mechanisms involving photosynthetic and antioxidant protection regulated by light intensity during in vitro and ex vitro plantlets acclimatization are poorly understood. Tobacco plantlets grown under in vitro and ex vitro environments were exposed to different light regimes to evaluate the role of photosynthesis and antioxidant protection. In vitro plantlets displayed a narrow photosynthetic capacity to cope with light as revealed by low net CO₂ assimilation (P_N), decreased actual quantum efficiency of photosystem II (ΦPSII) associated with non-induction of non-photochemical quenching (NPQ). In contrast, acclimated ex vitro plants showed strong stimulation in P_N whereas ΦPSII and NPQ remained at high levels. In vitro plantlets exposed to moderate light suffered strong oxidative stress associated with increased activities of superoxide dismutases, catalases and ascorbate peroxidases, revealing an ineffective antioxidant system. In contrast, ex vitro plants presented lower oxidative damage in parallel to unchanged enzymatic activities, indicating an efficient antioxidant steady state. The levels of reduced ascorbate (ASC) and glutathione (GSH) were also increased only in ex vitro plants in response to excess light. An integrative study based on correlation networks and principal component analyses (PCA) corroborate that the two plant groups indeed displayed contrasting acclimation processes. In conclusion, during in vitro to ex vitro transition, tobacco plantlets exposed to increasing light display physiological adjustments involving photosynthesis and improvement of the enzymatic and non-enzymatic antioxidant systems. These findings highlight the importance of integrative approaches to understand ex vitro acclimatization to environmental stimuli.

Plants form a substantive portion of human diet that contains a plethora of structurally diverse polyphenols. These polyphenols extend both nutritional as well as disease preventive benefits to the consumer. Many ancient medicinal systems like Ayurveda reiterate the consumption of particular polyphenol rich plant in specific medical condition. Therefore, it is necessary to create a database of the contents of different polyphenols in various plants. This study compiles a bibliographic review of polyphenol distribution in different plants along with their statistical analysis like Pearson's correlation matrix, cluster analysis, principal component and factor analysis, and non-metric multidimensional scaling. It was observed that caffeic acid and quercetin were the most abundant polyphenols in the plants. A significant positive correlation of umbelliferone was found with kaempferol and epicatechin. Species having close proximities on the basis of polyphenols were Parthenium hysterophorus, Rumex dentatus, Achyranthus aspera, Chenopodium ambrosoides, Cannabis sativa, Rhododendron arboreum, Alternanthera philoxeroides, Debregeasia longifolia and C. album. Factor analysis showed four underlying factors for polyphenols. Factor-1 had maximum loadings on epicatechin, umbelliferone and kaempferol. Gallic acid and catechin had maximum loadings on factor-2. Factor-3 had maximum loadings on chlorogenic acid and quercetin, and factor-4 had maximum loading on coumaric acid.

Preparations containing mainly lignified cell walls are effective adsorbents of hydrophobic carcinogens in vitro. Therefore, this innovative study aimed to structurally modify lignocellulosic materials in an enzymatic and environmentally friendly manner to improve the efficiency of sequestering three polycyclic aromatic hydrocarbons (PAHs) by adsorption. Submerged fermentations were performed to produce lignin peroxidase (LiP) in medium supplemented with three different lignocellulosic wastes (0.5% (w/v); açai seed, sugarcane bagasse, and seed coat of Brazil nut), followed by posterior hydrolysis of these three residues and subsequent adsorption to generate hydrolysate wastes. Among the three wastes, the açai seed was the most favourable carbon source for LiP production because a high enzyme activity peak was quickly achieved. Sugarcane bagasse residue was most readily hydrolysed (82.44%), and it had the highest increase in adsorption of the three PAHs tested dissolved in olive oil, from 15.67% of benzo[a]pyrene adsorbed before treatment to 39.45% after treatment. The depolymerisation of wastes may have increased binding sites for olive oil favouring the adsorption of PAHs on hydrolysed residues.

In the recent past, use of fossil fuel is on the rise and has triggered global energy crisis. So, renewable bioenergy is viewed as one of the means to tackle this problem. In this context, interest in microbial fuel cells (MFCs) is increasing and gaining popularity due to their ability to convert the organic wastes into renewable energy. Present investigation is on the bioelectricity production by a marine actinobacterium isolated from the Havelock island of the Andamans. Actinobacterial colonies were isolated from the sediment samples, using Kuster's agar. 19 morphologically distinct strains were subjected to cellulase enzyme screening. Among them, higher cellulose degradation capacity was found in the strain MHA15. This potential strain was selected and identified as a species close to Actinoalloteichus cyanogriseus. The strain was subjected to bioelectricity generation using sugarcane bagasse as substrate and was evaluated in a dual chambered microbial fuel cell. In the MFC, initial voltage output started at 160 mV and it gradually increased, reaching a maximum of 257 mV at the 3rd hour in the actinobacterial incubated bagasse solution. From the MFC analyzed sludge bagasse, microbial diversity was searched using different media and only actinobacterial colonies were observed. Conventional taxonomic characters of the isolates were identical to the potential actinobacterial strain MHA15 which produced bioelectricity from bagasse. Marine actinobacteria, with their unique nature, differ very much in many aspects from their terrestrial counterparts and are known to produce diverse spectra of novel and useful substances and excellent bioactivity. Results of the present study have ascertained that the marine actinobacterial strain Actinoalloteichus sp. MHA15 is capable of generating bioelectricity and there is much scope for utilizing such marine actinobacteria for large scale production of bioelectricity, after further in-depth studies.

The medicinal plant Avicennia marina was evaluated for their immunostimulatory activity on Pseudomonas fluorescens infested fish, Labeo rohita. The fish was dosed intraperitoneally at 10, 20 and 30 ppm concentrations of ethanolic leaves extract of A. marina and control. After 10, 20 and 30 days of treatments, the immunological, hematological and serum protein level of fish was assessed in control and treatments. All the concentration of plant leaves extract significantly enhanced the agglutination, hematological parameters and total serum protein on 30th days after treatment. The highest agglutination activity was observed in the group treated with 30 ppm concentration of A. marina on 20 days. The WBC, RBC and hemoglobin content was increased with increasing concentration of the treatments. The results, clearly indicates that A. marina leaves extract will be used as immunostimulatory agent to aquaculture for mass production of healthy fish.

Nematodes are pathogens of many important crops, including soybean. The main species found in Brazil are root-knot (Meloidogyne spp.), cyst (Heterodera glycines), root lesion (Pratylenchus brachyurus) and reniform (Rotylenculus reniformis) nematodes. Ureases are traditionally known for catalyzing the hydrolysis of urea to ammonia and carbon dioxide. Besides the main function, they present other independent biological roles, including toxic activities against insects, specially Coleoptera and Hemiptera, and fungi. In previous work, the DNA sequence encoding an insecticidal peptide - named Jaburetox - was identified in a Canavalia ensiformes urease gene. The recombinant Jaburetox exhibited toxicity against insects. Subsequently, the DNA sequence corresponding to Jaburetox was identified as part of the soybean Eu4 urease gene, with the resulting peptide named Soyuretox. In the present study, explants of soybean were transformed with Agrobacterium rhizogenes and ‘composite’ plants produced consisting of wild-type shoots and transgenic hairy roots overexpressing Soyuretox. Thereafter soybean plants overexpressing Soyuretox were obtained through bombardment transformation. Due to similarity between nematode and insect digestion mechanisms, we challenged composite and whole-transgenic plants with the nematode Meloidogyne javanica. Hairy roots overexpressing Soyuretox exhibited a significant reduction (48 %; p < 0.05) in the average reproductive factor when compared with empty-vector transformed hairy roots. Transgenic plants overexpressing Soyuretox also exhibited significant reduction (37.5 %; p < 0.05) in reproductive factor when compared with non-transformed plants. This study demonstrates the potential of Soyuretox in confering resistance against nematodes, representing a new alternative control method for nematodes in economically important crops.

Red propolis is a natural resin mixture produced by honeybees and presents a source of active compounds with a variety of biological activities. In this study, we describe the chemical characterization and potential antitumor activity of total extract of Brazilian red propolis and its fractions. Fractions were obtained through column chromatography revealing 14 different compounds in all samples, which were determined and distinguished of other isobar molecules by fragmentation pathways by ESI-MS/MS in positive mode. Some molecules as cis-asarone or trans-isoelemicin were identified and distinguish from elemicin compound and vestitol or isovestitol were also distinguished from neovestitol by fragmention pathway. Other important compounds as liquiritigenin was differentiated from isoliquiritigenin and formononetin from dalbergin.

MTT viability assay showed different toxicity in cell lines after exposition to total extract and fractions. Fractions 05 and 06 had more selectivity against HT-29 and HCT-116 cancer cells, respectively, in relation to normal cells. IC₅₀ (ranging of 72.45 ± 6.57 to 73.58 ± 1.00 μg/mL) in cancer cells were lower than reported in total extracts of propolis. May-Grunwald/Giemsa staining revealed cellular morphological changes after exposition to higher concentrations of red propolis extracts. Fractionation techniques can contribute to reduce chemical diversity verified in propolis mixtures, generating fractions with improved biological activity and contributing to the development of new strategies for discovery of natural compounds against cancer.