Conformation of amylose in water. I. Light-scattering and sedimentation-equilibrium measurements

The conformation of amylose in aqueous solution has been found to be dependent on its molecular weight. When the molecular weight of amylose is outside of the so-called “dissolving gap” described by Burchard (6500<M_r<160,000) it behaves as a random coil, whereas when its molecular weight is within the “dissolving gap,” it easily aggregates forming a rigid coil which is the B-type (retrograded) amylose. The conformation of this rigid coil is suggested to be a double helix.     

Maternal feeding strategies, child eating behaviors, and child BMI in low-income African-American preschoolers

Objective: To test the hypothesis that low‐income African‐American preschool children would have a higher BMI if their mothers reported greater “restriction” and “control” in feeding and if mothers reported that children showed greater “food responsiveness” and “desire to drink.” In addition, to test whether higher maternal “pressure to eat” would be associated with lower child BMI. Research Methods and Procedures: A questionnaire was completed by 296 low‐income African‐American mothers of preschool children. It assessed three constructs on maternal feeding strategies (“restriction,” “pressure to eat,” and “control”) and two on child eating behaviors (“food responsiveness” and “desire to drink”). Children's BMI was measured, and mothers’ BMI was self‐reported. Results: The mean (standard deviation) BMI z‐score of the children was 0.34 (1.5), and 44% of the mothers were obese (BMI ≥30 kg/m²). Only maternal “pressure to eat” had a significant overall association with child BMI z‐score (r = ?0.16, p < 0.01). Both maternal “restriction” and “control” were positively associated with children's BMI z‐score in the case of obese mothers (r = 0.20, p = 0.03 and r = 0.24, p = 0.007, respectively), but this was not so in the case of non‐obese mothers (r = ?0.16, p = 0.05 and r = ?0.07, p = 0.39, respectively). Discussion: Among low‐income African Americans, the positive association between maternal restriction and control in feeding and their preschoolers’ BMI was limited to obese mothers. Relations between parent feeding strategies and child weight status in this population may differ on the basis of maternal weight status.     

The passage and absorption of dietary and endogenous nitrogen in different regions of the digestive tract of rats given a single meal of 15N-labelled barley

Based on previously performed in vitro studies, which showed that hulless barley varieties could reduce large intestinal Salmonella Typhimurium var. Copenhagen proliferation in pigs, two in vivo experiments were conducted to prove these observations. In Experiment (Exp.) 1, 126 weaning piglets were randomly allocated into pens of seven animals each and fed one of six experimental diets. Three diets contained (75% as-fed) one of three hulless barley varieties with β-glucan (BG) contents ranging from 5 to 11% and amylose from 5 to 40%, and two diets contained a low BG and amylose hulless barley supplemented with isolated barley BG or raw potato starch. A hulled barley diet served as a control. Two piglets per pen (“Trojan” pigs) were orally infected with Salmonella Typhimurium var. Copenhagen (ST). The remaining five pigs per pen were designated “Contact” pigs. The ST shedding was determined over one week after infection. On day 6, the two Trojans and two random Contacts from each pen were euthanised and intestinal contents and mesenteric lymph nodes cultured for ST. Intestinal volatile fatty acids and microbial composition were determined. In Exp. 2, 126 piglets were assigned to one of three diets based on hulled or hulless barleys. The timeline, infection, sampling and analyses were similar as in Exp. 1 except samples were taken from four Contact pigs. Hulless barley varieties with high BG and amylose tended to decrease ST persistence in Exp. 1. Clostridia from cluster I in the colon were reduced with high amylose hulless barley or diets supplemented with potato starch (p < 0.05), whereas other microbial groups were not. Propionate increased (p < 0.05) and acetate decreased (p < 0.05) with hulless barley inclusion. Exp. 2 revealed a reduced ST shedding and reduced number of clostridia for high BG hulless barley as compared to common hulled barley and a low BG variety (p < 0.05). In conclusion, high BG hulless barley do not prevent ST colonisation but might help to reduce transmission in pigs, likely by supporting an intestinal environment limiting growth of this zoopathogen.     

Studies on the Extracellular Polysaccharides (EPS) Produced in vitro by Pseudomonas phaseolicola I. Indications for a Polysaccharide Resembling Alginic Acid in Seven P. syringae Pathovars

Extracellular polysaccharides (EPS) produced by Pseudomonas syringae pv. phaseolicola are obviously composed of two main components: the long known levan consisting of fructose, and a mannuronan consisting mainly of mannuronic acid (manA), thus resembling alginic acid (alginate). The identification of manA was established by TLC utilizing different developing systems, and by cellulose acetate electrophoresis in different buffers. References were authentic uronic acids and hydrolyzed authentic alginate. A rough quantification of the “alginate” present in crude EPS was achieved with a selective colour reaction which largely excluded compounds other than uronic acids. Levan was only synthesized with sucrose as primary carbon source. When grown on several other sugars and related compounds “alginate” was the predominant component of the EPS. Additionally, rhamnose, fucose, glucose and amino sugars were found in some instances in hydrolysates of crude EPS, suggesting the release of lipopolysaccharides (LPS) from the bacterial cell walls during culture. Growth on carbon sources not related to sugars resulted in these “LPS” as the main constituent of EPS. After cultivation with sucrose, the “alginate” was restricted to the “slime” fraction of the EPS. In the “capsular” fraction, levan was predominating. A screening program revealed the capacity to synthesize the “alginate” in six additional P. syringae pathovars: pisi, lachrymans, aptata, tomato, syringae, and glycinea. All of the strains tested so far produced levan from sucrose, however, the “alginate” was formed not by all of them. There was a tendency that fresh isolates produced more “alginate” than strains subcultured for an extended time in vitro. This was also true for the total amount of EPS.     

CELL SIZE DIFFERENTIATION IN THE BLOOM-FORMING DINOFLAGELLATE GYMNODINIUM CF. NAGASAKIENSE1

Two subpopulations differing essentially by their mean cell size were observed regularly in cultures and natural samples of the naked dinoflagellate Gymnodinium cf. nagasakiense Takayama et Adachi (currently known as Gyrodinium aureolum Hulburt), a species which frequently forms red tides in North European seas. “Large” cells represented the typical forms; they were morphologically similar to cells of the closely related Japanese species G. nagasakiense, which did not form any subpopulation of reduced size. “Small” and “large” cells of G. cf. nagasakiense had the same DNA content, but the nucleus of the former appeared to be much more condensed during interphase. Each cell type was able to divide and had its own growth dynamics; therefore, any intermediary between pure populations of “small” and of “large” cells were observed in culture. The “large” form generated a “small” cell by an atypical budding-like division, whereas the “small” form gave back a “large” form, once it ceased to divide, by simple enlargement of its cell body. Factory inducing cell size differentiation are yet unclear. Neither nitrogen nor phosphorus starvation induced a significant increase in the relative proportion of “small” and budding cells. Although cell size differentiation is associated with the formation of gametes in a variety of dinoflagellates, we demonstrated that “small” cells of G. cf. nagasakiense are able to divide asexually, in contrast to gametes of most other species. The high proliferative power of “small” cells as compared with normal cells suggests that they could play a significant role during red tides of G. cf. nagasakiense; in contrast, cells of the Japanese species G. Nagasakiense could sustain high growth rates with larger cell size because this species generally blooms in waters much warmer than those found in northern Europe.     

Molecular configuration of amylose and its complexes in aqueous solutions. Part II. Relation between the DP of helical segments of the amylose–iodine complex and the equilibrium concentration of free iodine

The iodine which is added to an aqueous amylose solution is bound only partly by the amylose while forming the blue complex and partly remains free. The equilibrium normality of the free and the bound iodine at half-saturation of amylose by iodine is designated as [I_f]_v and [I_b]_w, respectively. The stability of the poly iodine chain formed within the axis of amylose helices depends on its length, i.e., indirectly on the DP of the amylose helices: the greater this stability, the lower the [I_f]_v value. The amylose molecule consists of helical segments. Such a molecule may behave as a random coil. The average length of the helical segments in freshly prepared amylose-iodine complexes depends on temperature, pH, iodide concentration, the presence of other complex-forming agents, and the DP of the amylose. This latter factor is investigated in the present paper. By the aid of an automatically recording photometrictitrating device the coherent values of [I_b] and [I_f] were determined. Plotting these values against DP _n for mechanochemically degraded as well as for periodateo-xidized amyloses resulted in curves consisting of two linear sections. The break of the curves occurred between DP _n 110 and 130. It was concluded that below DP _n = 100 the DP of helical segments (= sDP _n) is identical to the DP _n of the total molecule, i.e., the molecule consists of only a single, relatively stiff helix. Above this limit the molecule contains several helical segments. The DP of these helical segments can be calculated as follows: sDP _n = 141.1 ? 10.2 × 10⁵[I_f]_v. This equation is considered to be valid for 0.5–0.6 mg. amylose in 100 ml. 0.1N HCl at 20°C., λ = 650 mμ, euuvet diameter 3.4 cm., the feed rate of the iodate-iodide titrating solution (in acid medium resulting in a 5 × 10^?3N I₂ solution with a molar iodide to iodine ratio of 1.5) is 0.4ml./min. Amylose molecules of, e.g., DP ⁿ = 1380 consist of an average of 11.4 segments having a DP of about 120 and consisting of an average of 15–18 helical turns.     

Morphological clines across a karyotypic zone of house mice in Central Italy

Multivariate morphometric differentiation between chromosomal races of the mouse Mus domesticus in Central Italy was investigated using a population of 2n = 22 “CB” karyotype, three populations of standard 2n = 40 karyotype, five populations of 2n = 22 “CD” karyotype and three populations from the hybrid zone between the latter two karyotypes. Whilst populations of different karyotype generally have significantly different morphometry, canonical analysis does not reveal that the populations ordinate into distinct aggregations based on karyotype, largely because the 2n = 22 “CD” populations are so diverse. Nevertheless, canonical analysis does reveal a significant cline in morphology across the contact zone between the 2n = 40 and 2n = 22 “CD” mice. The nature of this transition, i. e. a cline 1. within the 2n = 40 range, 2. within the hybrid range (but unrelated to chromosome number) and 3. within the 2n = 22 “CD” range, tends to indicate that the morphometric divergence is due to adaptation to the different ecological regimes across which these mice are distributed rather than the phylogenetic divergence of the karyotypic races.     

X-Ray diffraction of oriented amylose fibers. II. Structure of V amyloses

Oriented amylose fibers in the V form were prepared and subjected to x-ray analysis. Unit cells and the probable space group of P2₁2₁2₁ were determined for the V anhydrous and V hydrate forms of amylose; the analysis confirms previous predictions of these structures based on x-ray powder patterns. Chain folding in V amyloses is discussed in view of crystallographic evidence and folding experiments conducted with space-filling models. Reported also is evidence for amylose helices having diameters intermediate between 13.0 and 13.7 A.     

Corallite wall and septal microstructure in scleractinian reef corals: Comparison of molecular clades within the family Faviidae

Recent molecular phylogenies conflict with traditional scleractinian classification at ranks ranging from suborder to genus, challenging morphologists to discover new characters that better agree with molecular data. Such characters are essential for including fossils in analyses and tracing evolutionary patterns through geologic time. We examine the skeletal morphology of 36 species belonging to the traditional families Faviidae, Merulinidae, Pectiniidae, and Trachyphylliidae (3 Atlantic, 14 Indo‐Pacific, 2 cosmopolitan genera) at the macromorphological, micromorphological, and microstructural levels. Molecular analyses indicate that the families are not monophyletic groups, but consist of six family‐level clades, four of which are examined [clade XV = Diploastrea heliopora; clade XVI = Montastraea cavernosa; clade XVII (“Pacific faviids”) = Pacific faviids (part) + merulinids (part) + pectiniids (part) + M. annularis complex; clade XXI (“Atlantic faviids”) = Atlantic faviids (part) + Atlantic mussids]. Comparisons among molecular clades indicate that micromorphological and microstructural characters (singly and in combination) are clade diagnostic, but with two exceptions, macromorphologic characters are not. The septal teeth of “Atlantic faviids” are paddle‐shaped (strong secondary calcification axes) or blocky, whereas the septal teeth of “Pacific faviids” are spine‐shaped or multidirectional. Corallite walls in “Atlantic faviids” are usually septothecal, with occasional trabeculothecal elements; whereas corallite walls in “Pacific faviids” are usually trabeculothecal or parathecal or they contain abortive septa. Exceptions include subclades of “Pacific faviids” consisting of a) Caulastraea and Oulophyllia (strong secondary axes) and b) Cyphastrea (septothecal walls). Diploastrea has a diagnostic synapticulothecal wall and thick triangular teeth; Montastraea cavernosa is also distinct, possessing both “Pacific faviid” (abortive septa) and “Atlantic faviid” (paddle‐shaped teeth) attributes. The development of secondary axes is similar in traditional Atlantic faviids and mussids, supporting molecular results placing them in the same clade. Subclades of “Pacific faviids” reveal differences in wall structure and the arrangement and distinctiveness of centers of rapid accretion. J. Morphol. 272:66–88, 2011. © 2010 Wiley‐Liss, Inc.     

Dietary Restraint and Control Over “Wanting” Following Consumption of “Forbidden” Food

Eating behavior can be influenced by the rewarding value of food, i.e., “liking” and “wanting.” The objective of this study was to assess in normal‐weight dietary restrained (NR) vs. unrestrained (NU) eaters how rewarding value of food is affected by satiety, and by eating a nonhealthy perceived, dessert‐specific food vs. a healthy perceived, neutral food (chocolate mousse vs. cottage cheese). Subjects (24NR age = 25.0 ± 8.2 years, BMI = 22.3 ± 2.1 kg/m²; 26NU age = 24.8 ± 8.0 years, BMI = 22.1 ± 1.7 kg/m²) came to the university twice, fasted (randomized crossover design). Per test‐session “liking” and “wanting” for 72 items divided in six categories (bread, filling, drinks, dessert, sweets, stationery (placebo)) was measured, before and after consumption of chocolate mousse/cottage cheese, matched for energy content (5.6 kJ/g) and individual daily energy requirements (10%). Chocolate mousse was liked more than cottage cheese (P < 0.05). After consumption of chocolate mousse or cottage cheese, appetite and “liking” vs. placebo were decreased in NR and NU (P < 0.03), whereas “wanting” was only decreased in NR vs. NU (P ≤ 0.01). In NR vs. NU “wanting” was specifically decreased after chocolate mousse vs. cottage cheese; this decrease concerned especially “wanting” for bread and filling (P < 0.05). To conclude, despite similar decreases in appetite and “liking” after a meal in NR and NU, NR decrease “wanting” in contrast to NU. NR decrease “wanting” specifically for a nonhealthy perceived, “delicious,” dessert‐specific food vs. a nutritional identical, yet healthy perceived, slightly less “delicious,” “neutral” food. A healthy perceived food may thus impose greater risk for control of energy intake in NR.     

Solvent‐dependent conformation of amylose tris(phenylcarbamate) as deduced from scattering and viscosity data

The z‐average mean‐square radius of gyration 〈S²〉_z, the particle scattering function P(k), the second virial coefficient, and the intrinsic viscosity [η] have been determined for amylose tris(phenylcarbamate) (ATPC) in methyl acetate (MEA) at 25°C, in ethyl acetate (EA) at 33°C, and in 4‐methyl‐2‐pentanone (MIBK) at 25°C by light and small‐angle X‐ray scattering and viscometry as functions of the weight‐average molecular weight in a range from 2 × 10⁴ to 3 × 10⁶. The first two solvents attain the theta state, whereas the last one is a good solvent for the amylose derivative. Analysis of the 〈S²〉_z, P(k), and [η] data based on the wormlike chain yields h (the contour length or helix pitch per repeating unit) = 0.37 ± 0.02 and λ^?1 (the Kuhn segment length) = 15 ± 2 nm in MEA, h = 0.39 ± 0.02 and λ^?1 = 17 ± 2 nm in EA, and h = 0.42 ± 0.02 nm and λ^?1 = 24 ± 2 nm in MIBK. These h values, comparable with the helix pitches (0.37–0.40 nm) per residue of amylose triesters in the crystalline state, are somewhat larger than the previously determined h of 0.33 ± 0.02 nm for ATPC in 1,4‐dioxane and 2‐ethoxyethanol, in which intramolecular hydrogen bonds are formed between the C?O and NH groups of the neighbor repeating units. The slightly extended helices of ATPC in the ketone and ester solvents are most likely due to the replacement of those hydrogen bonds by intermolecular hydrogen bonds between the NH groups of the polymer and the carbonyl groups of the solvent. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 729–736, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Molecular configuration of amylose and its complexes in aqueous solutions. Part IV. Determination of DP of amylose by measuring the concentration of free iodine in solution of amylose–iodine complex

In aqueous solutions of the amylase–iodine complex the concentration of free iodine [I_f]_v after reaching equilibrium (or closely approximating it) is determined by the following factors: temperature, pH, concentration of iodide ions and amylose, and DP of amylose. In the present paper the role of temperature, amylose concentration, and DP has been investigated. At half-saturation of amylose by iodine, the reciprocal value of free iodine defines the equilibrium constant: 1/[I_f]_v = K. The relation between [I_f]_v, in normality and temperature is the following: 5 + log [I_f]_v = ?(2.132/T) + 8.52, for DP _n = 1290, 0.4 mg. amylose in 100 ml. 0.1N HCl. The value of the energy of activation E_a between 2 and 52°C. is 9.72 kcal./mole. The influence of amylose concentration [Am] on photometrically determined [I_f]_v, at 20°C, in the range of 0.1–1.2 mg./100 ml. 0.1 N HCl for DP _n = 1290 is: 5 + log [I_f]_v = 0.209 ? 0.047 log [Am]. At [Am] = 0.6 mg. amylose/ 100 ml. 0.1 N HCl and 20°C, the value of [I_f]_v depends on DP _n as follows: 5 + log [I_f]_v = 0.085 = + 0.222 log (10⁴/DP _n). These above equations are summarized by the relation: [I_f]_v = exp {16.865 ? (E_a/RT)}[Am]^0.047(10⁴/DP _n)^0.222 ×10^?5 Considering that the determination of [I_f]_v by automatic photometric titration can be performed quickly and with appropriate reproducibility, this method is convenient for a rapid empirical and approximate determination of DP of amylose on a microscale. The iodine-binding capacity [IBC] as well as the value of λ_max, have been also investigated as functions of DP _n, by photometric and by amperometric titration.     

FRESHWATER DINOFLAGELLATES OF BELIZE,C.A.

Freshwater dinoflagellates have not previously been reported from Belize, although there has been extensive work with marine dinoflagellates and some work with other freshwater groups. Freshwater dinoflagellates are more frequently observed in standing water and none have been observed in the several streams and rivers sampled since 1990. The goal in 1998 was to examine water samples from small ponds within hours of collection to improve the chance of observing swimming dinoflagellates. A plankton net was used and whole water samples also were collected. A small brown water pond on a peninsula and 30m from the Caribbean yielded a bloom of Thompsodinium intermedium. Dinoflagellates, including Peridinium centenniale, Katodinium sp., and Peridinium sp. in the Umbonatum Group, were observed within “Crocodile pond” and “Lily pond” on the mainland.     

Fluorescence of proteins in aqueous neutral salt solutions. II. Influence of monovalent cation chlorides, particularly cesium chloride.

The effects of varying concentrations of monovalent cation chlorides on the fluorescence of nine proteins were studied. These are discussed in terms of “direct” or “indirect” interactions with the aromatic amino acid residues. Cs⁺ is the only cation that quenches fluorescence of proteins due to “direct” interaction with aromatic amino acid residues. Quenching is due to collisional processes. An agreement with the Stern-Volmer relationship is shown and the values of [(K_Q)eff] and [(f_a)eff] are calculated. These values confirm that the fraction of fluorescence accessible to Cs⁺ belongs to the “exposed” fluorophors. The mechanism of quenching by Cs⁺ is due to the heavy-atom effect because phosphorescence enhancement is also seen at the same time. The chlorides of Na⁺, K⁺, Rb⁺, NH₄⁺, and Li⁺ do not have a similar effect on the fluorescence of all proteins. For a given protein a gradation of the same effect (i.e., quenching or dequenching) is seen. Interactions with factors that “inderectly” affect fluorescence of any protein are involved and the structural features of the protein are responsible for such “indirect” effects. The results indicate that neutral salts can act in more than one manner. The changes in fluorescence are indicative of electrostatic and lyotropic effects of ions. Only electrostatic interactions which occur in the vicinity of tryptophan in proteins are reflected. Li⁺ shows strong interactions with proteins. In 4 M LiCl, BSA, papain, and trypsin show fluorescence changes that are indicative of changes in protein structure.     

SYNTHETIC AGROPYRON-ELYMUS HYBRIDS: III. ELYMUS CANADENSIS X AGROPYRON CANINUM,A. TRACHYCAULUM,AND A. STRIATUM

Hybrids were produced with relative ease from controlled crosses of Elymus canadensis L. with European Agropyron caninum (L.) Beauv., North American A. trachycaulum (Link) Malte ex H. F. Lewis, and Asian A. striatum Nees ex Steud. All hybrids appeared to be completely sterile and were, for the most part, morphologically intermediate between their parents. The E. canadensis × A. caninum hybrids were exceptionally vigorous and leafy and may have some potential as forage grasses if fertility can be achieved. All parent plants were tetraploid, 2n = 28, and they behaved cytologically as alloploids. Chromosome pairing in the hybrids indicated that both E. canadensis genomes were closely homologous with those of A. trachycaulum and somewhat less homologous with those of A. caninum. Interchanged and inverted chromosome segments apparently constitute the major differences between E. canadensis, A. trachycaulum, and A. caninum genomes; however, cryptic structural differences must also exist. Partial homologies were detected between one A. striatum and E. canadensis genome, but their other genomes were distinctly different. The genome relations between the parent species were expressed in terms of the following genome formulas: E. canadensis, S₁S₁X₁X₁; A. trachycaulum, S₂S₂X₂X₂; A. caninum, S₃S₃X₃X₃ : and A. striatum S₄S₄YY or X₄X₄YY, where “S” refers to a genome derived from A. spicatum and “X” and “Y” are genomes of unknown origin.     

Helicobacter pylori outer inflammatory protein A (OipA) suppresses apoptosis of AGS gastric cells in vitro

Outer inflammatory protein A (OipA) is an important virulence factor associated with gastric cancer and ulcer development; however, the results have not been well established and turned out to be controversial. This study aims to elucidate the role of OipA in Helicobacter pylori infection using clinical strains harbouring oipA “on” and “off” motifs. Proteomics analysis was performed on AGS cell pre‐infection and postinfection with H. pylori oipA “on” and “off” strains, using liquid chromatography/mass spectrometry. AGS apoptosis and cell cycle assays were performed. Moreover, expression of vacuolating cytotoxin A (VacA) was screened using Western blotting. AGS proteins that have been suggested previously to play a role or associated with gastric disease were down‐regulated postinfection with oipA “off” strains comparing to oipA “on” strains. Furthermore, oipA “off” and ΔoipA cause higher level of AGS cells apoptosis and G0/G1 cell‐cycle arrest than oipA “on” strains. Interestingly, deletion of oipA increased bacterial VacA production. The capability of H. pylori to induce apoptosis and suppress expression of proteins having roles in human disease in the absence of oipA suggests that strains not expressing OipA may be less virulent or may even be protective against carcinogenesis compared those expressing OipA. This potentially explains the higher incidence of gastric cancer in East Asia where oipA “on” strains predominates.     

Techniques for Universal Evaluation of Astringency of Green Tea Infusion by the Use of a Taste Sensor System

A practical method for universal evaluation of the astringency of green tea infusion by a taste sensor system was established. The use of EGCg aqueous solution as a standard enabled analysis with high accuracy and reproducibility. The sensor output was converted into taste-intensity on the basis of Weber’s and Weber-Fechner laws, which was named the “EIT _ast ” value (“EIT” and “ast” are abbreviations for “Estimated Intensity of Taste” and “astringency” respectively). It was clarified that green tea infusion is to be classified into eight grades on the EIT _ast scale. Furthermore, the high correlation of the EIT _ast value with the human gustatory sense and the high stability of the taste sensor were proved.     

Anatomical and biochemical aspects of interaction between roots of chickpea and Fusarium oxysporum f. sp. ciceris race 2

Roots of the susceptible “JG-62” and resistant “WR-315” chickpeas (Cicer arietinum L.) were inoculated with a conidial suspension of Fusarium oxysporum f. sp. ciceris. Anatomical and biochemical studies were carried out in a time-course manner to elucidate the infection process and plant defence reactions. Scanning electron microscope images revealed fungal colonisation in the root hair region. Early occurrence of fungal biofilms associated with the infected “JG-62” root epidermis was also visualised. After 96 h of inoculation, a gradual accumulation of polysaccharide positive deposits was observed in the xylem vessels of the infected “JG-62” roots. Fungal mycelium was observed in the vessel lumen of infected “JG-62” after 22 days of inoculation. Due to fungal invasion during this period, some of the vessels also appeared collapsed in “JG-62”, whereas vessels in “WR-315” remained intact. The host plant defence responses specifically linked to the susceptible interactions were the induction of ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase in roots and shoots.     

Study of artemisinin and sugar accumulation in Artemisia vulgaris and Artemisia dracunculus “hairy” root cultures

We studied the effect of genetic transformation on biologically active compound (artemisinin and its co-products (ART) as well as sugars) accumulation in Artemisia vulgaris and Artemisia dracunculus “hairy” root cultures. Glucose, fructose, sucrose, and mannitol were accumulated in A. vulgaris and A. dracunculus “hairy” root lines. Genetic transformation has led in some cases to the sugar content increasing or appearing of nonrelevant for the control plant carbohydrates. Sucrose content was 1.6 times higher in A. vulgaris “hairy” root lines. Fructose content was found to be 3.4 times higher in A. dracunculus “hairy” root cultures than in the control roots. The accumulation of mannitol was a special feature of the leaves of A. vulgaris and A. dracunculus control roots. A. vulgaris “hairy” root lines differed also in ART accumulation level. The increase of ART content up to 1.02?mg/g DW in comparison with the nontransformed roots (up to 0.687?mg/g DW) was observed. Thus, Agrobacterium rhizogenes-mediated genetic transformation can be used for obtaining of A. vulgaris and A. dracunculus “hairy” root culture produced ART and sugars in a higher amount than mother plants.