The complexation between holothurian triterpene glycosides and Chl as the basis for lipid-saponin carriers of subunit protein antigens

The ability of holothurian triterpene glycosides (cucumarioside A₂-2 from Cucumaria japonica, cucumarioside G₁ from C. fraudatrix, frondoside A from C. frondosa, and holotoxin A₁ from Apostichopus japonicus) to form supramolecular lipid-saponin complexes was studied. TEM demonstrated that all the studied compounds form supramolecular cholesterol-saponin complexes (nanoparticles) in aqueous medium. The complexes formed by cucumarioside A₂-2, holotoxin A₁, and frondoside A had a tubular structure and fundamentally differed in the structure from the particles produced by cucumarioside G₁. The morphology of the nanoparticles formed by cucumarioside A₂-2, holotoxin A₁, and cucumarioside G₁ changed depending on the fraction of cholesterol in the lipid-saponin system; however, this pattern was not observed for frondoside A. At the same molar fraction of cholesterol in the lipid-saponin system, cucumarioside A₂-2 formed the particles with the most pronounced tubular structure; the cholesterol-saponin complexes of holotoxin A₁ had a less pronounced tubular structure, whereas the structure of frondoside A particles was extremely heterogeneous. Comparative analysis of the morphology of the described supramolecular complexes and specific structural features of the glycosides demonstrated that the structure of the corresponding nanoparticles depended on the degree of branching of the carbohydrate moiety in the glycoside molecule and the complexation with cholesterol was determined by the specific features of aglycone structure. Thus, the feasibility of producing new generation antigen carriers using the complexes in question was proved.     

Immunostimulatory characteristics of a novel adjuvant on the basis of cucumarioside A<Subscript>2</Subscript>-2 and monogalactosyldiacylgycerol

A novel antigen carrier has been formulated on the basis of a cucumarioside-A₂-2 triterpene glycoside (CD) complex with cholesterol and monogalactosyldiacylglycerol from Ahnfeltia tobuchiensis (MGDGAt) and Ulva fenestrate (MGDGUf). Morphological and immunostimulative characteristics of the carrier were studied. Electron microscopy experiments demonstrated the formation of homogeneous tubular structures in a mixture of CD, cholesterol, and MGDG in molar ratio of 1: 2: 3. In animals immunized by the carrier bearing pore forming protein monomer of pseudotuberculosis agent CD and MGDG synergically affected synthesis of specific antibodies, interleukin-2, and γ-interferon and delayed hypersensitivity reaction when compared to Freund’s complete adjuvant or to immunostimulatory complexes between Quillaja saponaria saponins and phosphatidylcholine from egg yolk. The immunostimulatory effect depends upon the composition of polyunsaturated fatty acids of MGDG. The new tubular adjuvant carrier is a competitive adjuvant, as it includes CD obtained from far-eastern sea cucumber commercial species Cucumaria japonica, and MGDG from seaweed.     

Influence of Daily Short-Term Temperature Drops on Respiration to Photosynthesis Ratio in Chilling-Sensitive Plants

Cucumber (Cucumis sativus L.), tomato (Solanum lycopersicum L.), and sweet pepper (Capsicum annuum L.) plants were subjected daily over 13 days to short-term (2 h) temperature drops to 12, 8, 4, and 1°C (DROP treatments) at the end of night periods, and effects of these chilling treatments on the ratio of dark respiration in leaves (R_d) to gross photosynthesis (A_g) were examined. The results showed that DROP treatments affected the R_d/A_g ratio in leaves: this ratio increased significantly in cucumber and tomato plants and was slightly affected in pepper plants. When the temperature drops to 12°C were applied, the increase in R_d/A_g ratio in cucumber and tomato plants was entirely due to the rise in R_d. In the case of temperature drops to 8°C and below, the increase in R_d/A_g was determined by both elevation of R_d and the concurrent decrease in Ag. In cucumber plants, the extent of Ag and R_d changes increased with the DROP severity, i.e., with lowering the temperature of DROP treatment. The inhibition of photosynthesis by DROP treatment in cucumber plants was accompanied by the diminished efficiency of light energy use for photosynthesis and by the increase in the light compensation point. The elevation in R_d/A_g ratio in cucumber plants was accompanied by the decline in growth characteristics, such as accumulation of aboveground biomass, plant height, and leaf area. It was concluded that the R/A ratio is an important indicator characterizing the adaptive potential of chilling-sensitive plant species and their response to daily short-term temperature drops.     

A new commensal ostracod <Emphasis Type="Italic">Asterositus ohtsukai</Emphasis> n. g., n. sp. (Paradoxostomatidae) on the sea star <Emphasis Type="Italic">Sclerasterias euplecta</Emphasis> (Fisher) (Asteriidae) and its feeding habits

A new commensal ostracod Asterositus ohtsukai n. g., n. sp. (Podocopida: Cytheroidea: Paradoxostomatidae) is described. This new taxon occurs on the ambulacral grooves and wreath of pedicellariae around superomarginal spines of the sea star Sclerasterias euplecta (Fisher) (Asteroidea: Forcipulatida: Asteriidae). Although the family Paradoxostomatidae Brady & Norman, 1889 contains four ectoparasitic or commensal genera, the association with asteroideans has never hitherto been reported. Morphological observations suggested that A. ohtsukai n. g., n. sp. is closely associated with the host sea star as it typically has distal hooks on the antenna and fifth to seventh limbs, and specialised mandibula and maxillula structures that are considered adaptations to a commensal life-style. In addition, this study discussed the feeding habits of A. ohtsukai n. g., n. sp. based on comparison with previous works. The extremely reduced palp and endites of maxillula of A. ohtsukai n. g., n. sp. imply that they have unique feeding habits that are not based on the feeding function of maxillula. From morphological comparisons with siphonostomatoid copepods, we suggest that A. ohtsukai n. g., n. sp. may feed on the body of host sea star by injuring them with styliform needle-like mandibular coxa and sucking the tissues, body fluid, or mucus with the suctorial disc on the oral cone.     

Polyhydroxylated steroid compounds from the Far Eastern starfish <Emphasis Type="Italic">Distolasterias nipon</Emphasis>

Two new steroid glycosides: distolasteroside D₆, (24S)-24-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6α,8,15β,16β,24-hexaol, and distolasteroside D₇, (22E,24R)-24-O-(β-D-xylopyranosyl)-5α-cholest-22-ene-3β,6α,8,15β,24-pentaol were isolated along with the previously known distolasterosides D₁, D₂, and D₃, echinasteroside C, and (25S)-5α-cholestane-3β4β,6α,7α,8,15α,16β,26-octaol from the Far Eastern starfish Distolasterias nipon. The structures of new compounds were elucidated by NMR spectroscopy and MALDI TOF mass spectrometry. Like neurotrophins, distolasterosides D₁, D₂, and D₃ were shown to induce neuroblast differentiation in a mouse neuroblastoma C1300 cell culture.     

Genetic population structure and low genetic diversity in the over-exploited sea cucumber <Emphasis Type="Italic">Holothuria edulis</Emphasis> Lesson, 1830 (Echinodermata: Holothuroidea) in Okinawa Island

Understanding genetic connectivity is fundamental for ecosystem-based management of marine resources. Here we investigate the metapopulation structure of the edible sea cucumber Holothuria edulis Lesson, 1830 across Okinawa Island, Japan. This species is of economic and ecological importance and is distributed from the Red Sea to Hawai‘i. We examined sequence variation in fragments of mitochondrial cytochrome oxidase subunit I (COI) and 16S ribosomal RNA (16S), and nuclear histone (H3) at six locations across Okinawa Island. We found higher haplotype diversity for mtDNA (COI: Hd = 0.69 and 16S: Hd = 0.67) and higher heterozygosity of nDNA (H3: H _E = 0.39) in populations from the west coast of Okinawa compared to individuals from populations on the east coast (COI: Hd = 0.40; 16S: Hd = 0.21; H3: H _E = 0.14). Overall population structure was significant (AMOVA results for COI: Φ _ST = 0.49, P < 0.0001; 16S: Φ _ST = 0.34, P < 0.0001; H3: Φ _ST = 0.12, P < 0.0001). One population in the east, Uruma, showed elevated pairwise Φ _ST values in comparisons with all other sites and a marked reduction of genetic diversity (COI: Hd = 0.25 and 16S: Hd = 0.24), possibly as a consequence of a shift to a more dominant asexual reproduction mode. Recent reports have indicated that coastal development in this area influences many marine organisms, and ecosystem degradation in this location could cause the observed decrease of genetic diversity and isolation of H. edulis in Uruma. Our study should provide valuable data to help with the urgently needed management of sea cucumber populations in Okinawa, and indicates particular attention needs to be paid to vulnerable locations.     

Description of Four New Species of Genus <Emphasis Type="Italic">Acanthaegilips</Emphasis> Ashmead, 1897 (Hymenoptera: Figitidae: Anacharitinae) from Colombia

There are four new species of the Neotropical Anacharitinae genus Acanthaegilips Ashmead, 1897: A. boyacensis sp. n., A. curvis sp. n., A. timidus sp. n., and A. truncatus sp. n. The diagnostic characters of this new species and data about their morphological variability and similarities with other Acantahegilips species are discussed. An updated key of genus Acanthaegilips is included.     

Effect of <Emphasis Type="Italic">Codonopsis pilosula</Emphasis> on Immune and Digestion in Sea Cucumber, <Emphasis Type="Italic">Apostichopus japonicus</Emphasis>

A 8-week trial was conducted to evaluate the effect of Codonopsis pilosula on immune and digestion in sea cucumber. The results showed that the total coelomocytes counts (TCC), phagocytic activity and superoxide anion production (O₂^-), superoxide dismutase (SOD), acid phosphatase (ACP), phenoloxidase (PO) activities in coelomocytes of sea cucumbers were improved significantly after 28 or 42 days. Again dietary C. pilosula had a positive impact by activating the RNA expression levels of complement component 3 (C3), lysozyme and protease, amylase and alginase activities in the gut. Finally the resistance of A. japonicus against Vibrio splendidus was enhanced.     

Diversity of <Emphasis Type="Italic">A</Emphasis> mating type in <Emphasis Type="Italic">Lentinula edodes</Emphasis> and mating type preference in the cultivated strains

Diversity of A mating type in Lentinula edodes has been assessed by analysis of A mating loci in 127 strains collected from East Asia. It was discovered that hypervariable sequence region with an approximate length of 1 kb in the A mating locus, spanning 5′ region of HD2-intergenic region-5′ region of HD1, could represent individual A mating type as evidenced by comprehensive mating analysis. The sequence analysis revealed 27 A mating type alleles from 96 cultivated strains and 48 alleles from 31 wild strains. Twelve of them commonly appeared, leaving 63 unique A mating type alleles. It was also revealed that only A few A mating type alleles such as A1, A4, A5, and A7 were prevalent in the cultivated strains, accounting for 62.5% of all A mating types. This implies preferred selection of certain A mating types in the process of strain development and suggests potential role of A mating genes in the expression of genes governing mushroom quality. Dominant expression of an A mating gene HD1 was observed from A1 mating locus, the most prevalent A allele, in A1-containing dikaryons. However, connections between HD1 expression and A1 preference in the cultivated strains remain to be verified. The A mating type was highly diverse in the wild strains. Thirty-six unique A alleles were discovered from relatively small and confined area of mountainous region in Korean peninsula. The number will further increase because no A allele has been recurrently observed in the wild strains and thus newly discovered strain will have good chances to contain new A allele. The high diversity in small area also suggests that the A mating locus has evolved rapidly and thus its diversity will further increase.     

Genetic structure of Japanese sea cucumbers (<Emphasis Type="Italic">Apostichopus japonicus</Emphasis>) along the Sanriku coast supports the effect of earthquakes and related tsunamis

The Japanese common sea cucumber (Apostichopus japonicus) is a major marine product from Sanriku, Japan, but its populations were severely affected by the 2011 Tohoku earthquake, possibly decreasing its genetic diversity and increasing its extinction risk. In this study, we estimated the genetic structure and diversity of sea cucumbers from Touni and Yamada Bays of Sanriku over 4 years after the earthquake. The between-population genetic structure was estimated using two mitochondrial DNA regions (cytochrome c oxidase subunit I and 16S rDNA). Genetic differentiation (as measured by pairwise F_ST) was not significant between locations. Thus, even after the tsunami, gene flow and genetic diversity among the two sea cucumber populations were maintained. Our data also suggested that sea cucumbers in Sanriku experienced population expansion of about 0.20–0.24 million years ago, during the stable Mindel-Riss interglacial period. We conclude that A. japonicus populations in Sanriku could maintain their genetic structure throughout multiple disastrous tsunamis over the past several 1000 years. The high dispersal ability of planktonic larvae may enable the entrance of new recruits, thereby reducing risks associated with genetic structure and diversity changes stemming from mass die-offs in a given body of water from the past to the present.     

QTL mapping of domestication and diversifying selection related traits in round-fruited semi-wild Xishuangbanna cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L. var. <Emphasis Type="Italic">xishuangbannanesis</Emphasis>)

Key message

QTL analysis revealed 11 QTL underlying flowering time and fruit size variation in the semi-wild Xishuangbanna cucumber, of which, FT6.2 and FS5.2 played the most important roles in determining photoperiod-dependent flowering time and round-fruit shape, respectively.

Abstract

Flowering time and fruit size are two important traits in domestication and diversifying selection in cucumber, but their genetic basis is not well understood. Here we reported QTL mapping results on flowering time and fruit size with F₂ and F_2:3 segregating populations derived from the cross between WI7200, a small fruited, early flowering primitive cultivated cucumber and WI7167, a round-fruited, later flowering semi-wild Xishuangbanna (XIS) cucumber. A linkage map with 267 microsatellite marker loci was developed with 138 F₂ plants. Phenotypic data of male and female flowering time, fruit length and diameter and three other traits (mature fruit weight and number, and seedling hypocotyl length) were collected in multiple environments. Three flowering time QTL, FT1.1, FT5.1 and FT6.2 were identified, in which FT6.2 played the most important role in conferring less photoperiod sensitive early flowering during domestication whereas FT1.1 seemed more influential in regulating flowering time within the cultivated cucumber. Eight consensus fruit size QTL distributed in 7 chromosomes were detected, each of which contributed to both longitudinal and radial growth in cucumber fruit development. Among them, FS5.2 on chromosome 5 exhibited the largest effect on the determination of round fruit shape that was characteristic of the WI7167 XIS cucumber. Possible roles of these flowering time and fruit size QTL in domestication of cucumber and crop evolution of the semi-wild XIS cucumber, as well as the genetic basis of round fruit shape in cucumber are discussed.

     

Glyceriformia (Annelida) from the deep sea of the Atlantic sector of the Southern Ocean

The faunas living in the vast deep sea regions around the Antarctic are very poorly known. This is especially true for the biodiversity of polychaetes inhabiting these remote areas. Therefore, we report new morphological data of Glyceriformia from the ANDEEP cruises to the South Atlantic Ocean and the Southern Ocean. Based on benthos samples from three expeditions aboard R/V POLARSTERN, two species of Glyceridae (Glycera capitata, G. diva) and four species of Goniadidae (Bathyglycinde sibogana, B. stepaniantsae, Goniada maculata, Progoniada regularis) were studied. Furthermore, new morphological details (especially for the previously unknown tail) for the rarely found taxon B. stepaniantsae are given. The distribution patterns of the different taxa demonstrated that some species have a high dispersal capability and show an extended level of eurybathy, whereas other species are restricted to the deep sea.     

The effects of condensed tannins derived from senescing <Emphasis Type="Italic">Rhizophora mangle</Emphasis> leaves on carbon,nitrogen and phosphorus mineralization in a <Emphasis Type="Italic">Distichlis spicata</Emphasis> salt marsh soil

Background and aims

Low nitrogen negatively affects soil fertility and plant productivity. Glucose-6-phosphate dehydrogenase (G6PDH) and Epichloë gansuensis endophytes are two factors that are associated with tolerance of Achnatherum inebrians to abiotic stress. However, the possibility that E. gansuensis interacts with G6PDH in enhancing low nitrogen tolerance of host grasses has not been examined.

Methods

A. inebrians plants with (E+) and without E. gansuensis (E?) were subjected to different nitrogen concentration treatments (0.1, 1, and 7.5 mM). After 90 days, physiological studies were carried out to investigate the participation of G6PDH in the adaption of host plants to low nitrogen availability.

Results

Low nitrogen retarded the growth of A. inebrians. E+ plants had higher total dry weight, chlorophyll a and b contents, net photosynthesis rate, G6PDH activity, and GSH content, while having lower plasma membrane (PM) NADPH oxidase activity, NADPH/NADP⁺ ratios, and MDA and H₂O₂ than in E? A. inebrians plants under low nitrogen concentration.

Conclusions

The presence of E. gansuensis played a key role in maintaining the growth of the A. inebrians plants under low nitrogen concentration by regulating G6PDH activity and the NADPH/NADP⁺ ratio and improving net photosynthesis rate.

     

Biosynthesis of two quercetin <Emphasis Type="Italic">O</Emphasis>-diglycosides in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Various flavonoid glycosides are found in nature, and their biological activities are as variable as their number. In some cases, the sugar moiety attached to the flavonoid modulates its biological activities. Flavonoid glycones are not easily synthesized chemically. Therefore, in this study, we attempted to synthesize quercetin 3-O-glucosyl (1→2) xyloside and quercetin 3-O-glucosyl (1→6) rhamnoside (also called rutin) using two uridine diphosphate-dependent glycosyltransferases (UGTs) in Escherichia coli. To synthesize quercetin 3-O-glucosyl (1→2) xyloside, sequential glycosylation was carried out by regulating the expression time of the two UGTs. AtUGT78D2 was subcloned into a vector controlled by a Tac promoter without a lacI operator, while AtUGT79B1 was subcloned into a vector controlled by a T7 promoter. UDP-xyloside was supplied by concomitantly expressing UDP-glucose dehydrogenase (ugd) and UDP-xyloside synthase (UXS) in the E. coli. Using these strategies, 65.0 mg/L of quercetin 3-O-glucosyl (1→2) xyloside was produced. For the synthesis of rutin, one UGT (BcGT1) was integrated into the E. coli chromosome and the other UGT (Fg2) was expressed in a plasmid along with RHM2 (rhamnose synthase gene 2). After optimization of the initial cell concentration and incubation temperature, 119.8 mg/L of rutin was produced. The strategies used in this study thus show promise for the synthesis of flavonoid diglucosides in E. coli.     

The effects of polymorphisms in <Emphasis Type="Italic">growth hormone</Emphasis> and <Emphasis Type="Italic">growth hormone receptor</Emphasis> genes on production and reproduction traits in Aberdeen-Angus cattle (<Emphasis Type="Italic">Bos taurus</Emphasis> L., 1758)

The study was aimed to analyze the relation between individual genotypes and allelic variants of SNPs g.2141C>G of growth hormone gene, g.914T>A and g.257A>G of growth hormone receptor gene with growth and reproduction traits and to evaluate the populationgenetic structure in Aberdeen-Angus cattle (Bos taurus L., 1758) sample of Eastern Ukraine according SNPs studied. Allele C of SNP g.2141C>G has a positive correlation with birth weight, body stature, bigger rump, udder and total exterior evaluation score, shorter calving interval and better calve birth weight and negative correlation with calve average daily gain. Allele T of SNP g.914T>A has positive correlation with the muscle and udder size; live weight in each age, average daily gain, weight and average daily gain of calves born conform to the principle AA>TT≥TA. SNP g.257A>G showed a positive correlation for G allele with muscle size. The population is in equilibrium for SNPs g.2141C>G and g.257A>G, and in disequilibrium for SNP g.914T>A. The analysis showed no linkage disequilibrium between SNPs g.914T>A and g.257A>G. Inbreeding coefficient F_ST in Aberdeen-Angus group studied was 16.1%.     

Two new steroid glycosides from the Far East starfish <Emphasis Type="Italic">Hippasteria kurilensis</Emphasis>

Two new steroid glycosides were isolated from the Far East starfish Hippasteria kurilensis collected in the Sea of Okhotsk. They were characterized as (22E,24R)-3-O-(2-O-methyl-β-D-xylopyranosyl)-24-O-[2-O-methyl-β-D-xylopyranosyl-(1→5)-α-L-arabinofuranosyl]-5α-cholest-22-ene-3β,4β,6α,7α,8,15β,24-heptaol (kurilensoside I) and (24S)-3-O-(2-O-methyl-β-D-xylopyranosyl)-24-O-(α-L-arabinofuranosyl)-5α-cholestane-3β,4β,6β,15α,24-pentaol (kurilensoside J). In addition, the earlier known glycosides linkosides F and L1, leviusculoside G, forbeside L, desulfated echinasteroside, and granulatoside A were isolated and identified. The structures of the new compounds were established with the help of two-dimentional NMR spectroscopy and mass- spectrometry.     

Simple generalisation of a mesophyll resistance model for various intracellular arrangements of chloroplasts and mitochondria in C<Subscript>3</Subscript> leaves

The classical definition of mesophyll conductance (g _m) represents an apparent parameter (g _m,app) as it places (photo)respired CO₂ at the same compartment where the carboxylation by Rubisco takes place. Recently, Tholen and co-workers developed a framework, in which g _m better describes a physical diffusional parameter (g _m,dif). They partitioned mesophyll resistance (r _m,dif = 1/g _m,dif) into two components, cell wall and plasmalemma resistance (r _wp) and chloroplast resistance (r _ch), and showed that g _m,app is sensitive to the ratio of photorespiratory (F) and respiratory (R _d) CO₂ release to net CO₂ uptake (A): g _m,app = g _m,dif/[1?+?ω(F?+?R _d)/A], where ω is the fraction of r _ch in r _m,dif. We herein extend the framework further by considering various scenarios for the intracellular arrangement of chloroplasts and mitochondria. We show that the formula of Tholen et al. implies either that mitochondria, where (photo)respired CO₂ is released, locate between the plasmalemma and the chloroplast continuum or that CO₂ in the cytosol is completely mixed. However, the model of Tholen et al. is still valid if ω is replaced by ω(1?σ), where σ is the fraction of (photo)respired CO₂ that experiences r _ch (in addition to r _wp and stomatal resistance) if this CO₂ is to escape from being refixed. Therefore, responses of g _m,app to (F?+?R _d)/A lie somewhere between no sensitivity in the classical method (σ =1) and high sensitivity in the model of Tholen et al. (σ =0).