Effects of monoclonal antibodies directed against murine T lymphocyte cell surface antigens on lymphokine production by cloned T lymphocytes reactive with class I MHC or Mls alloantigens

Monoclonal antibodies recognizing murine T lymphocyte cell surface structures implicated in T lymphocyte-mediated cytolysis, including Lyt-2, L3T4, LFA-1, and a cytolytic T lymphocyte (CTL) clonotypic determinant, were used as probes to investigate the role of these structures in lymphokine production by T cell clones induced by antigen or lectin. The clone-specific antibody 384.5 bound to and inhibited antigen-induced lymphokine production by the L3 CTL clone, but did not affect lymphokine production by other T cell clones. Antibodies against the T cell surface structures Lyt-2 or L3T4, which are expressed by mutually exclusive T cell subsets, inhibited antigen-induced lymphokine production by class I major histocompatibility complex (MHC) antigen-reactive CTL clones or an M1s-reactive helper T lymphocyte (HTL) clone, respectively. Antibody against the broadly distributed LFA-1 molecule inhibited antigen-induced lymphokine production by all of the clones tested. Lectin-induced lymphokine production by cloned T cells was not inhibited by the clonotypic antibody, anti-Lyt-2, or anti-LFA-1; slight inhibition of the HTL clone was observed with the anti-L3T4 antibody. None of these structures appear to be uniquely involved with a particular functional response. Our results suggest that each of these structures is involved with the interactions between the effector cell and the stimulating cell leading to lymphokine production.     

Environmental control of reproductive phenology and the effect of pollen supplementation on resource allocation in the cleistogamous weed, Ruellia nudiflora (Acanthaceae)

• Background and Aims Mixed reproductive strategies may have evolved as a response of plants to cope with environmental variation. One example of a mixed reproductive strategy is dimorphic cleistogamy, where a single plant produces closed, obligately self-pollinated (CL) flowers and open, potentially outcrossed (CH) flowers. Frequently, optimal environmental conditions favour production of more costly CH structures whilst economical and reliable CL structures are produced under less favourable conditions. In this study we explore (1) the effect of light and water on the reproductive phenology and (2) the effect of pollen supplementation on resource allocation to seeds in the cleistogamous weed Ruellia nudiflora.• Methods Split-plot field experiments were carried out to assess the effect of shade (two levels: ambient light vs. a reduction of 50 %) and watering (two levels: non-watered vs. watered) on the onset, end and duration of the production of three reproductive structures: CH flowers, CH fruit and CL fruit. We also looked at the effect of these environmental factors on biomass allocation to seeds (seed weight) from obligately self-pollinated flowers (CL), open-pollinated CH flowers and pollen-supplemented CH flowers.• Key Results CH structures were produced for a briefer period and ended earlier under shaded conditions. These conditions also resulted in an earlier production of CL fruit. Shaded conditions also produced greater biomass allocation to CH seeds receiving extra pollen.• Conclusions Sub-optimal (shaded) conditions resulted in a briefer production period of CH structures whilst these same conditions resulted in an earlier production of CL structures. However, under sub-optimal conditions, plants also allocated more resources to seeds sired from CH flowers receiving large pollen loads. Earlier production of reproductive structures and relatively larger seed might improve subsequent success of CL and pollen-supplemented CH seeds, respectively.     

Production of extracellular fibers by tobacco leaf epidermal protoplasts

Protoplasts prepared from the upper epidermis of tobacco (Nicotiana tabacum L.) leaves produce tubular structures which are highly fluorescent in the presence of Calcofluor white. The presence of Ca²⁺ in the incubation medium appears to be necessary for the production of these fibers. A commercial cellulase preparation destroyed these structures and inhibited their production.     

Production and localization of restrictocin in Aspergillus restrictus.

The production and secretion of restrictocin (a cytotoxin that cleaves ribosomal RNA) by cultures of the fungus Aspergillus restrictus was investigated. Previous studies have indicated that restrictocin production in liquid culture coincides with the appearance of differentiated cell structures. A study of the correlation between the appearance of differentiated structures and restrictocin production was conducted with A. restrictus grown on agar medium. Restrictocin was found to be associated with the cell mass of the agar-grown culture (in contrast to liquid cultures), and was first observed when aerial hyphae emerged. Restrictocin levels increased until the time of conidiation, after which they fell off sharply. No restrictocin could be found in the agar medium. The presence of restrictocin upon and within various cell structures was determined by immunofluorescent laser microscopy. This study showed that restrictocin became localized to the conidiophores and phialides during the process of conidiation. Prior to this, restrictocin was found within the hyphae in localized concentrations that may correspond to secretory vesicles.     

Concentrically arranged endoplasmic reticulum containing some lamellae (bar-like structure) in alveolar type II cells of rat lung

We examined in vivo the effect of pilocarpine (a cholinergic agent) and cycloheximide (an inhibitor of protein synthesis) on the "bar-like structures" in alveolar type II cells of rat lung to clarify their origin and significance in pulmonary surfactant production and secretion. Lungs were examined with an electron microscope using ultrathin sectioning, freeze-fracture technique, and morphometry. The bar-like structures in type II cells consisted of a concentrically arranged endoplasmic reticulum containing some amount of osmiophilic periodic material similar to the lamellae of lamellar bodies. Pilocarpine induced the accumulation of lamellar bodies of normal size which paralleled the increase in the number of bar-like structures in the cytoplasm of the type II cells. Cycloheximide induced a decrease in size of the lamellar bodies and an enlargement of the bar-like structures. Our morphological findings suggest that: The phospholipid that would normally be incorporated into the lamellar bodies might be sequestered instead in the concentrically arranged endoplasmic reticulum, forming the bar-like structures, and The enlargement and the increased number of bar-like structures may be responsible in part for the changed metabolic process of surfactant production by alveolar type II cells.     

Antiviral RNA interference responses induced by Semliki Forest virus infection of mosquito cells: characterization, origin, and frequency-dependent functions of virus-derived small interfering RNAs

RNA interference (RNAi) is an important mosquito defense mechanism against arbovirus infection. In this paper we study the processes underlying antiviral RNAi in Aedes albopictus-derived U4.4 mosquito cells infected with Semliki Forest virus (SFV) (Togaviridae; Alphavirus). The production of virus-derived small interfering RNAs (viRNAs) from viral double-stranded RNA (dsRNA) is a key event in this host response. dsRNA could be formed by RNA replication intermediates, by secondary structures in RNA genomes or antigenomes, or by both. Which of these dsRNAs is the substrate for the generation of viRNAs is a fundamental question. Here we used deep sequencing of viRNAs and bioinformatic analysis of RNA secondary structures to gain insights into the characteristics and origins of viRNAs. An asymmetric distribution of SFV-derived viRNAs with notable areas of high-level viRNA production (hot spots) and no or a low frequency of viRNA production (cold spots) along the length of the viral genome with a slight bias toward the production of genome-derived viRNAs over antigenome-derived viRNAs was observed. Bioinformatic analysis suggests that hot spots of viRNA production are rarely but not generally associated with putative secondary structures in the SFV genome, suggesting that most viRNAs are derived from replicative dsRNA. A pattern of viRNAs almost identical to those of A. albopictus cells was observed for Aedes aegypti-derived Aag2 cells, suggesting common mechanisms that lead to viRNA production. Hot-spot viRNAs were found to be significantly less efficient at mediating antiviral RNAi than cold-spot viRNAs, pointing toward a nucleic acid-based viral decoy mechanism to evade the RNAi response.     

Three-dimensional structures of enzymes useful for beta-lactam antibiotic production

Significant advances have been made in the structure-based engineering of enzymes useful for beta-lactam antibiotic production. Structure-based engineering of penicillin G acylase and cephalosporin acylase has resulted in improved enzymes for use in enzymatic production processes. The structures of many other enzymes that could be used in the production of beta-lactam antibiotics, such as enzymes from the beta-lactam biosynthetic pathway and beta-lactam antibiotic-converting enzymes, have been determined. The interest in these structures suggests that the future may see an even more extensive use of rationally engineered biocatalysts in antibiotic production than today.     

A transient tobacco expression system coupled to MALDI-TOF-MS allows validation of the impact of differential targeting on structure and activity of a recombinant therapeutic glycoprotein produced in plants

Tobacco-based transient expression was employed to elucidate the impact of differential targeting to subcellular compartments on activity and quality of gastric lipase as a model for the production of recombinant glycoproteins in plants. Overall N-linked glycan structures of recombinant lipase were analyzed and for the first time sugar structures of its four individual N-glycosylation sites were determined in situ by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) on a trypsin digest without isolation or deglycosylation of the peptides. Three glycosylation sites contain both complex-type N-glycans and high-mannose-type structures, the fourth is exclusively linked to high-mannose glycans. Although the overall pattern of glycan structures is influenced by the targeting, our results show that the type of glycans found linked to a given Asn residue is largely influenced by the physico-chemical environment of the site. The transient tobacco system combined with MALDI-TOF-MS appears to be a useful tool for the evaluation of glycoprotein production in plants.     

Differentiation and melanin production in hyaline and pigmented strains of Microdochium bolleyi

The effect of various compounds on growth, melanin biosynthesis and cell differentiation was studied in a hyaline (SH25) and a pigmented (SH25B) strain of Microdochium bolleyi. Dark pigment production by the hyaline strain was induced by the presence of DOPA and indole in the medium, both of which are intermediates in the tyrosine pathway of melanin biosynthesis. These substrates also induced conidia and chlamydospore production, structures which were not normally seen in the hyaline strain. The systemic fungicide, tricyclazole, inhibited melanin synthesis in the pigmented strain but not the development of chlamydospore-like cell structures.     

Evidence of sustained populations of a small reef fish on artificial structures. Does depth affect production on artificial reefs?

The length frequencies and age structures of resident Pseudanthias rubrizonatus (n = 407), a small protogynous serranid, were measured at four isolated artificial structures on the continental shelf of north-western Australia between June and August 2008, to determine whether these structures supported full (complete size and age-structured) populations of this species. The artificial structures were located in depths between 82 and 135 m, and growth rates of juveniles and adults, and body condition of adults, were compared among structures to determine the effect of depth on potential production. All life-history stages, including recently settled juveniles, females and terminal males, of P. rubrizonatus were caught, ranging in standard length (L(s)) from 16·9 to 96·5 mm. Presumed ages estimated from whole and sectioned otoliths ranged between 22 days and 5 years, and parameter ±s.e. estimates of the von Bertalanffy growth model were L(∞) = 152 ± 34 mm, k = 0·15(±0·05) and t(0) = -1·15(±0·15). Estimated annual growth rates were similar between shallow and deep artificial structures; however, otolith lengths and recent growth of juveniles differed among individual structures, irrespective of depth. The artificial structures therefore sustained full populations of P. rubrizonatus, from recently settled juveniles through to adults; however, confirmation of the maximum age attainable for the species is required from natural populations. Depth placement of artificial reefs may not affect the production of fish species with naturally wide depth ranges.     

Parasexually produced hybrids between female and male plants of Griffithsia tenuis C. Agardh,a red alga

Somatic cell fusion between vegetative cells of a male and a female isolate of Griffithsia tenuis, a marine red alga, has been obtained. Hybrid cells have been isolated and they have regenerated new plants. Almost all these hybrid plants made reproductive structures. In nearly half these cases the first 3–10 cells of the hybrid filament produced reproductive structures chracteristic of the tetrasporic (diploid) phase rather than the sexual (haploid) phase of the life cycle of this alga. However as these filaments continued to grow, cells further along the filament began to produce sexual, either female or male, reproductive structures. The observations suggest that the production of tetrasporangial branches does not require the fusion of male and female nucleic; rather, male and female nucleic remaining separate, act in concert to produce these structures, and in subsequent cell divisions the nuclei of one sex may be left behind allowing the nuclei of the remaining sex to direct the production of sexual branches.     

Free radical production by hydroxy-salen manganese complexes studied by ESR and XANES

Three salen-Mn(II) complexes bearing hydroxyl groups in either the ortho, para or meta positions have been synthesized and the structures of the metal complexes and their potential to produce free radicals investigated by electron spin resonance (ESR) and X-ray absorption near edge structures (XANES) spectroscopy. All three compounds were shown to generate a high level of superoxide anions in dimethyl sulfoxide (DMSO) solution. The production of oxygen radicals results from a one electron process oxidation of Mn(II) species leading to the formation Mn(III) redox state species, as revealed by a higher XANES edge energy of 2.7 eV. The formation of superoxide anion was characterized by ESR, both directly and via the use of a spin-trapping method. Under reductive condition in the presence of ascorbic acid, the reduction of Mn(III) to Mn(II) leads to the production of hydroxyl radicals by the ortho and para compounds. The efficient production O(2)*- by such salen-Mn complexes could be useful to evaluate the scavenging properties of antioxidant molecules.     

Plants as concept generators for biomimetic light-weight structures with variable stiffness and self-repair mechanisms

1 Introduction Over the last few years, plants have proved to be areal treasure trove as models for the construction of bio-logically inspired technical structures and materials [1–5].One ongoing project of the Competence Network ‘Plantsas Concept Generators for Biomimetic Materials andTechnologies’deals with the construction of light-weightstructures with variable stiffness and rapid self-repairmechanisms based on plant structures [6, 7] …     

Patterns of resource allocation in the dioecious alpine herb Aciphylla simplicifolia (Apiaceae)

Abstract Patterns of reproductive and vegetative biomass allocation were compared in male and female plants of the alpine herb Aciphylla simplicifolia. Male and female plants had similar vegetative biomass but differed in the pattern of resource allocation. Inflorescences of males and females were similar in weight at the time of flowering, but differed in biomass allocation to some structures within the inflorescences, particularly those associated with ovule production and pollinator attraction (number and size of flowers). At the time of fruit production, female inflorescences were 2.6 times heavier than at flowering with developing fruit six times heavier than flowers. In addition to the increase in biomass allocated to structures associated with the provisioning and dissemination of seed, support structures (main and side stalks) were also heavier. As a result of this additional investment of resources at the time of fruit production, the reproductive effort (RE) of female plants was much higher than that of males: 37% of above ground biomass compared with 21% for males. Differences in RE did not change with plant size; however, allocation to reproduction appeared to be a constant proportion of biomass over nearly all plant sizes sampled. These results show that sex‐specific resource allocation can be a complex of temporal and morphological patterns.     

Functional Groups Determine Biochar Properties (pH and EC) as Studied by Two-Dimensional 13C NMR Correlation Spectroscopy

While the properties of biochar are closely related to its functional groups, it is unclear under what conditions biochar develops its properties. In this study, two-dimensional (2D) ¹³C nuclear magnetic resonance (NMR) correlation spectroscopy was for the first time applied to investigate the development of functional groups and establish their relationship with biochar properties. The results showed that the agricultural biomass carbonized to biochars was a dehydroxylation/dehydrogenation and aromatization process, mainly involving the cleavage of O-alkylated carbons and anomeric O-C-O carbons in addition to the production of fused-ring aromatic structures and aromatic C-O groups. With increasing charring temperature, the mass cleavage of O-alkylated groups and anomeric O-C-O carbons occurred prior to the production of fused-ring aromatic structures. The regression analysis between functional groups and biochar properties (pH and electrical conductivity) further demonstrated that the pH and electrical conductivity of rice straw derived biochars were mainly determined by fused-ring aromatic structures and anomeric O-C-O carbons, but the pH of rice bran derived biochars was determined by both fused-ring aromatic structures and aliphatic O-alkylated (HCOH) carbons. In summary, this work suggests a novel tool for characterising the development of functional groups in biochars.     

Two new isoflavonoid glucosides from the roots of Achyranthes bidentata and their activities against nitric oxide production

Two new isoflavonoid glucosides, Achyranthosides A and B, were isolated from the roots of Achyranthes bidentata. Their structures were established through extensive analyses using ¹H, ¹³C NMR, HSQC, HMBC, NOESY, and HREISMS spectroscopic data. The structures of the new compounds are characterized by the methoxyl groups substituted on the specific positions of the phenyl rings. The two compounds were evaluated for their anti-inflammatory activities on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 murine macrophage cells. The compounds showed significant inhibition on LPS-induced NO production.     

Water-based nanoparticulate polymeric system for protein delivery

This article features a new production technology for nanoparticles comprised of multicomponent polymeric complexes that are candidates for delivery vehicles of biological molecules such as proteins and drugs. Biocompatible and mostly natural polymers are fabricated into thermodynamically stable nanoparticles insoluble in water and buffered media, in the absence of organic solvents, using two types of processing: batch and continuous. Careful choice of construction materials and the superposition of several interacting principles during their production allow for the customization of the physicochemical properties of the structures. Detailed experiments in batch and continuous systems allowed time-dependent stoichiometric characterization of the production process and an understanding of fundamental assembly principles of such supramolecular structures. Continuous-flow production is shown to provide more consistent data in terms of product quality and consistency, with further possibility of process development and commercialization. The development of nanoparticles using the described methodology is expected to lead to a flexible nanoparticle drug delivery system for medical applications, which has particular bearing to the slow release of drugs, antigens (for vaccine design), and genes (for gene therapy). Several chemistries of particles are presented. Copyright John Wiley & Sons, Inc.     

Coronatine elicits phytoalexin production in rice leaves (Oryza sativa L.) in the same manner as jasmonic acid

The phytotoxin coronatine induced the accumulation of the flavonoid phytoalexins sakuranetin and momilactone A in rice leaves. Coronatine-inducible sakuranetin production was under the control of kinetin and ascorbic acid (AsA), as observed with jasmonic acid (JA). The effects of kinetin and AsA on the activity of coronatine indicated that coronatine might elicit sakuranetin production in a manner similar to JA. The similarity of both their structures and the manner of elicitation of coronatine and JA suggest that they might interact at the same active site(s) to lead to phytoalexin production.     

Assessing the influence of physical,geochemical and biological factors on anaerobic microbial primary productivity within hydrothermal vent chimneys

Chemosynthetic primary production supports hydrothermal vent ecosystems, but the extent of that productivity and its governing factors have not been well constrained. To better understand anaerobic primary production within massive vent deposits, we conducted a series of incubations at 4, 25, 50 and 90 °C using aggregates recovered from hydrothermal vent structures. We documented in situ geochemistry, measured autochthonous organic carbon stable isotope ratios and assessed microbial community composition and functional gene abundances in three hydrothermal vent chimney structures from Middle Valley on the Juan de Fuca Ridge. Carbon fixation rates were greatest at lower temperatures and were comparable among chimneys. Stable isotope ratios of autochthonous organic carbon were consistent with the Calvin–Benson–Bassham cycle being the predominant mode of carbon fixation for all three chimneys. Chimneys exhibited marked differences in vent fluid geochemistry and microbial community composition, with structures being differentially dominated by gamma (γ) or epsilon (ε) proteobacteria. Similarly, qPCR analyses of functional genes representing different carbon fixation pathways showed striking differences in gene abundance among chimney structures. Carbon fixation rates showed no obvious correlation with observed in situ vent fluid geochemistry, community composition or functional gene abundance. Together, these data reveal that (i) net anaerobic carbon fixation rates among these chimneys are elevated at lower temperatures, (ii) clear differences in community composition and gene abundance exist among chimney structures, and (iii) tremendous spatial heterogeneity within these environments likely confounds efforts to relate the observed rates to in situ microbial and geochemical factors. We also posit that microbes typically thought to be mesophiles are likely active and growing at cooler temperatures, and that their activity at these temperatures comprises the majority of endolithic anaerobic primary production in hydrothermal vent chimneys.     

Role of exopolysaccharides in Pseudomonas aeruginosa biofilm formation and architecture

Pseudomonas aeruginosa is an opportunistic human pathogen and has been established as a model organism to study bacterial biofilm formation. At least three exopolysaccharides (alginate, Psl, and Pel) contribute to the formation of biofilms in this organism. Here mutants deficient in the production of one or more of these polysaccharides were generated to investigate how these polymers interactively contribute to biofilm formation. Confocal laser scanning microscopy of biofilms formed in flow chambers showed that mutants deficient in alginate biosynthesis developed biofilms with a decreased proportion of viable cells than alginate-producing strains, indicating a role of alginate in viability of cells in biofilms. Alginate-deficient mutants showed enhanced extracellular DNA (eDNA)-containing surface structures impacting the biofilm architecture. PAO1 ΔpslA Δalg8 overproduced Pel, and eDNA showing meshwork-like structures presumably based on an interaction between both polymers were observed. The formation of characteristic mushroom-like structures required both Psl and alginate, whereas Pel appeared to play a role in biofilm cell density and/or the compactness of the biofilm. Mutants producing only alginate, i.e., mutants deficient in both Psl and Pel production, lost their ability to form biofilms. A lack of Psl enhanced the production of Pel, and the absence of Pel enhanced the production of alginate. The function of Psl in attachment was independent of alginate and Pel. A 30% decrease in Psl promoter activity in the alginate-overproducing MucA-negative mutant PDO300 suggested inverse regulation of both biosynthesis operons. Overall, this study demonstrated that the various exopolysaccharides and eDNA interactively contribute to the biofilm architecture of P. aeruginosa.