Development and application of photoautotrophic micropropagation plant system

Research has revealed that most chlorophyllous explants/plants in vitro have the ability to grow photoautotrophically (without sugar in the culture medium), and that the low or negative net photosynthetic rate of plants in vitro is not due to poor photosynthetic ability, but to the low CO₂ concentration in the air-tight culture vessel during the photoperiod. Moreover, numerous studies have been conducted on improving the in vitro environment and investigating its effects on growth and development of cultures/plantlets on nearly 50 species since the concept of photoautotrophic micropropagation was developed more than two decades ago. These studies indicate that the photoautotrophic growth in vitro of many plant species can be significantly promoted by increasing the CO₂ concentration and light intensity in the vessel, by decreasing the relative humidity in the vessel, and by using a fibrous or porous supporting material with high air porosity instead of gelling agents such as agar. This paper reviews the development and characteristics of photoautotrophic micropropagation systems and the effects of environmental conditions on the growth and development of the plantlets. The commercial applications and the perspective of photoautotrophic micropropagation systems are discussed.     

Gut microbiota in wild and captive Guizhou snub‐nosed monkeys,Rhinopithecus brelichi

Many colobine species—including the endangered Guizhou snub‐nosed monkey (Rhinopithecus brelichi) are difficult to maintain in captivity and frequently exhibit gastrointestinal (GI) problems. GI problems are commonly linked to alterations in the gut microbiota, which lead us to examine the gut microbial communities of wild and captive R. brelichi. We used high‐throughput sequencing of the 16S rRNA gene to compare the gut microbiota of wild (N = 7) and captive (N = 8) R. brelichi. Wild monkeys exhibited increased gut microbial diversity based on the Chao1 but not Shannon diversity metric and greater relative abundances of bacteria in the Lachnospiraceae and Ruminococcaceae families. Microbes in these families digest complex plant materials and produce butyrate, a short chain fatty acid critical to colonocyte health. Captive monkeys had greater relative abundances of Prevotella and Bacteroides species, which degrade simple sugars and carbohydrates, like those present in fruits and cornmeal, two staples of the captive R. brelichi diet. Captive monkeys also had a greater abundance of Akkermansia species, a microbe that can thrive in the face of host malnutrition. Taken together, these findings suggest that poor health in captive R. brelichi may be linked to diet and an altered gut microbiota.     

Molecular cloning,expression patterns and subcellular localization of porcine <Emphasis Type="Italic">TMCO1</Emphasis> gene

The product of transmembrane and coiled-coil domains 1 (TMCO1) gene is a member of DUF841 superfamily of several eukaryotic proteins with unknown function. The partial DNA sequence of porcine TMCO1 was first cloned with a pig 567 bp ORF encoding 188 amino acids. By tissues expression analysis, the TMCO1 was found highly expressed in the liver, kidney and heart. The porcine TMCO1 protein was subsequently demonstrated to localize in the mitochondrion by confocal fluorescence microscopy. This data provides an important basis for conducing further studies on the functions and regulatory mechanisms underlying the role of TMCO1 gene.     

Evolution of the thaumastocheliform lobsters (Crustacea,Decapoda, Nephropidae)

Deep‐sea lobsters previously assigned to the family Thaumastochelidae Bate, 1888, the thaumastocheliforms, have very distinctive, greatly unequal first chelipeds, with the right side extremely elongate and pectinate, and in having short, quadrate pleonal pleura. Despite interesting morphology and a long taxonomic history, the phylogeny of the group has received little detailed analysis. Here, we conduct a species‐level phylogenetic analysis of the thaumastocheliforms based on morphological and molecular data (three mitochondrial genes: COI, 16S rDNA and 12S rDNA; two nuclear protein‐coding genes: H3 and NaK) to robustly reconstruct their evolutionary history and estimate divergence times. Separate and combined analyses of all data sources support thaumastocheliform monophyly, but as a clade deeply nested within the Nephropidae supporting recent synonymy of Thaumastochelidae with Nephropidae. Combined and molecular‐only analyses support generic monophyly of all three thaumastocheliform genera and Dinochelus as sister to Thaumastochelopsis, fully corroborating the current, morphology‐based taxonomy. In contrast, Thaumastocheles is recovered as paraphyletic in morphology‐only analyses owing to minimal character support. The Cretaceous–Paleogene Oncopareia was recovered as a stem‐lineage thaumastocheliform. The fossil record indicates that the thaumastocheliforms once lived in shallow, continental shelf depths, but moved into deeper water in the Cenozoic where they occur today. The thaumastocheliforms originated in northern Europe during the Mid‐Late Cretaceous and later dispersed westwards to the south‐eastern Pacific through the western Atlantic and eastwards to the western Pacific through the Indian Ocean. Thaumastochelopsis can be considered the most derived thaumastocheliform genus based on the degree of structural reduction relative to other thaumastocheliforms, its remote geographical occurrence (Australia) from the hypothesised place of origin (northern Europe) and its more recent estimated divergence than other genera (28 Mya for the MRCA of extant species of the genus).     

Rewiring central carbon metabolism for tyrosol and salidroside production in Saccharomyces cerevisiae

Metabolic engineering of Saccharomyces cerevisiae for high-level production of aromatic chemicals has received increasing attention in recent years. Tyrosol production from glucose by S. cerevisiae is considered an environmentally sustainable and safe approach. However, the production of tyrosol and salidroside by engineered S. cerevisiae has been reported to be lower than 2 g/L to date. In this study, S. cerevisiae was engineered with a push-pull-restrain strategy to efficiently produce tyrosol and salidroside from glucose. The biosynthetic pathways of ethanol, phenylalanine, and tryptophan were restrained by disrupting PDC1, PHA2, and TRP3. Subsequently, tyrosol biosynthesis was enhanced with a metabolic pull strategy of introducing PcAAS and EcTyrA^M53I/A354V. Moreover, a metabolic push strategy was implemented with the heterologous expression of phosphoketolase (Xfpk), and then erythrose 4-phosphate was synthesized simultaneously by two pathways, the Xfpk-based pathway and the pentose phosphate pathway, in S. cerevisiae. Furthermore, the heterologous expression of Xfpk alone in S. cerevisiae efficiently improved tyrosol production compared with the coexpression of Xfpk and phosphotransacetylase. Finally, the tyrosol yield increased by approximately 135-folds, compared with that of parent strain. The total amount of tyrosol and salidroside with glucose fed-batch fermentation was over 10 g/L and reached levels suitable for large-scale production.     

Identification of Key Factors Involved in the Biosorption of Patulin by Inactivated Lactic Acid Bacteria (LAB) Cells

The purpose of this study was to identify the key factors involved in patulin adsorption by heat-inactivated lactic acid bacteria (LAB) cells. For preventing bacterial contamination, a sterilization process was involved in the adsorption process. The effects of various physical, chemical, and enzymatic pre-treatments, simultaneous treatments, and post-treatments on the patulin adsorption performances of six LAB strains were evaluated. The pre-treated cells were characterized by scanning electron microscopy (SEM). Results showed that the removal of patulin by viable cells was mainly based on adsorption or degradation, depending on the specific strain. The adsorption abilities were widely increased by NaOH and esterification pre-treatments, and reduced by trypsin, lipase, iodate, and periodate pre-treatments. Additionally, the adsorption abilities were almost maintained at pH 2.2–4.0, and enhanced significantly at pH 4.0–6.0. The effects of sodium and magnesium ions on the adsorption abilities at pH 4 were slight and strain-specific. A lower proportion of patulin was released from the strain with higher adsorption ability. Analyses revealed that the physical structure of peptidoglycan was not a principal factor. Vicinal OH and carboxyl groups were not involved in patulin adsorption, while alkaline amino acids, thiol and ester compounds were important for patulin adsorption. Additionally, besides hydrophobic interaction, electrostatic interaction also participated in patulin adsorption, which was enhanced with the increase in pH (4.0–6.0).     

Cytotoxicity and structure–activity relationships of four α-N-heterocyclic thiosemicarbazone derivatives crystal structure of 2-acetylpyrazine thiosemicarbazone

A series of thiosemicarbazone ligands, HL¹ (2-acetylpyrazine thiosemicarbazone), HL² (2-acetylpyrazine N(4)-methylthiosemicarbazone), HL³ (2-benzoylpyridine thiosemicarbazone) and HL⁴ (2-benzoylpyridine N(4)-methylthiosemicarbazone), have been synthesized. The crystal structure of HL¹ has been determined by single-crystal X-ray diffraction. Hydrogen bonds link the different components to stabilize the crystal structure. The antitumor activity of the four ligands were tested against K562 leucocythemia and BEL7402 liver cancer cell lines. All the thiosemicarbazones showed significant antitumor activity. Different substituents on the ligands show different levels of antitumor activity. By comparison with the other thiosemicarbazone species studied, HL⁴ with substitution at N(4) position in thiosemicarbazone along with 2-benzoylpyridine is the most active thiosemicarbazone ligand with IC₅₀ = 0.002 μm in the K562 leucocythemia cell line and 0.138 μm in the BEL7402 liver cancer cell line, respectively.