Allergic inflammation as a hypothesis for the expulsion of worms from tissues: A review

Introduction; comparison of studies of mice infected with Trichinella spiralis; discussion; summary; references.     

Evaluation of Streptomyces strains isolated from herbal vermicompost for their plant growth-promotion traits in rice

Six actinomycetes, CAI-13, CAI-85, CAI-93, CAI-140, CAI-155 and KAI-180, isolated from six different herbal vermi-composts were characterized for in vitro plant growth-promoting (PGP) properties and further evaluated in the field for PGP activity in rice. Of the six actinomycetes, CAI-13, CAI-85, CAI-93, CAI-140 and CAI-155 produced siderophores; CAI-13, CAI-93, CAI-155 and KAI-180 produced chitinase; CAI-13, CAI-140, CAI-155 and KAI-180 produced lipase; CAI-13, CAI-93, CAI-155 and KAI-180 produced protease; and CAI-13, CAI-85, CAI-140 and CAI-155 produced ß-1-3-glucanase whereas all the six actinomycetes produced cellulase, hydrocyanic acid and indole acetic acid (IAA). The actinomycetes were able to grow in NaCl concentrations of up to 8%, at pH values between 7 and 11, temperatures between 20 and 40 °C and compatible with fungicide bavistin at field application levels. In the rice field, the actinomycetes significantly enhanced tiller numbers, panicle numbers, filled grain numbers and weight, stover yield, grain yield, total dry matter, root length, volume and dry weight over the un-inoculated control. In the rhizosphere, the actinomycetes also significantly enhanced total nitrogen, available phosphorous, % organic carbon, microbial biomass carbon and nitrogen and dehydrogenase activity over the un-inoculated control. Sequences of 16S rDNA gene of the actinomycetes matched with different Streptomyces species in BLAST analysis. Of the six actinomycetes, CAI-85 and CAI-93 were found superior over other actinomycetes in terms of PGP properties, root development and crop productivity. qRT-PCR analysis on selected plant growth promoting genes of actinomycetes revealed the up-regulation of IAA genes only in CAI-85 and CAI-93.     

The problem of interlab variation in methods for mitochondrial disease diagnosis: enzymatic measurement of respiratory chain complexes

Due to the large importance of mitochondrial function for numerous diseases the detection of respiratory chain defects for diagnostic purposes is an important task of mitochondrial medicine. For comparing the methods, standard mitochondrial homogenate prepared from bovine skeletal muscle was sent on dry ice to 14 labs of 8 countries. Activities of complexes I, I + III, II, II + III, IV (cytochrome c oxidase) and V (F0F1ATPase) as well as of citrate synthase were measured. For all enzymes the results differed at more than one order of magnitude. From eight labs we were able to compare the results with their control values for human skeletal muscle. Four labs found normal activity of cytochrome-c-oxidase whereas three labs found higher and one lab found lower activities compared to the own controls. Since all labs used different temperatures (25, 30 and 37 degrees C) in one lab the temperature dependencies were measured experimentally. The temperature correction did not much reduce the divergence of the results. It is concluded that differences in the lab protocols are the reason for the large variation of results. Since the experimental results strongly depend on the used method a strict standardization is necessary.     

植物基因组研究进展(综述)

目前集中在模式植物拟南芥、水稻的基因组研究进展迅速,基因组测序和物理作图极大地便利了基于分子标记图的基因克隆,并增加了对植物基因组的组织、结构和进化的认识。     

Metal-humic complexes and plant micronutrient uptake: a study based on different plant species cultivated in diverse soil types

There are several studies in the literature dealing with the effect of metal-humic complexes on plant metal uptake, but none of them correlate the physicochemical properties of the complexes with agronomic results. Our study covers both aspects under various experimental conditions. A humic extract (SHE) obtained from a sapric peat was selected for preparing the metal–humic complexes used in plant experiments. Fe–, Zn– and Cu–humic complexes with a reaction stoichiometry of 2:0.25 (humic:metal, w/w) were chosen after studying their stability and solubility with respect to pH (6–9) and the humic:metal reaction stoichiometry. Wheat and alfalfa plants were greenhouse cultured in pots containing one of three model soils: an acid, sandy soil and two alkaline, calcareous soils. Treatments were: control (no additions), SHE (53 mg kg^–1 of SHE), and metal (Cu, Zn and Fe)–SHE complexes (2.5 and 5 mg kg^–1 of metal rate and a SHE concentration to make 53 mg kg ^–1). Cu- and Zn–humic complexes significantly (p0.05) increased the plant uptake and the DTPA-extractable soil fraction of complexed micronutrients in most plant–soil systems. However, these effects were associated with significant increases (p0.05) of shoot and root dry weight only in alfalfa plants. In wheat, significant increases of root and shoot dry matter were only observed in the Cu–humic treated plants growing in the acid soil, where Cu deficiency was more intense. The Fe–humic complex did not increase Fe plant assimilation in any plant–soil system, but SHE increased Fe-uptake and/or DTPA-extractable soil Fe in the wheat–calcareous soil systems. These results, taken together with those obtained from the study of the pH- and SHE:metal ratio-dependent SHE complex solubility and stability, highlight the importance of the humic:Fe complex stoichiometry on iron bioavailability as a result of its influence on complex solubility.     

Biological control of snail-borne diseases: a review

The need for alternatives to chemical control of snail-borne diseases and the growing interest in biological control methods are noted. Two groups of natural enemies of snails reviewed as especially promising for biological control are competing and predatory snails, and predatory fly larvae. Potentially useful natural enemies of the intramolluscan stages of trematodes include microsporidian infections and antagonistic trematode larvae. More unusual methods of biological control include the use of a toxic plant product (endod) and genetic manipulation of snails to decrease their susceptibility to trematode infection. The disappointing progress in biological control of snail-borne diseases in the past is attributed largely to delay in recognizing the need for alternatives to chemical control and to lack of interdisciplinary communication.     

Diseases of crayfish: a review

A systematic review of parasites, pathogens and commensals of freshwater crayfish has been conducted. All major groups of disease causing agents have been covered including viruses, bacteria, fungi, protistans and metazoans. Most agents tend to cause limited problems for crayfish. Exceptions to this include fungi, bacteria and viruses. However, in many cases, these tend to be isolated reports in either a specific geographical location or in individual animals. The apparent absence of pathology associated with these agents in crayfish should not be taken to suggest that movements of crayfish to new geographical areas is necessarily acceptable. Several examples are given where seemingly healthy animals have been moved to new areas leading to mortality of other crayfish within the same area as a direct result of transmission of pathogens to naïve hosts. Some future research needs are proposed, including the need for pathogen characterisation and production of disease-free crayfish for aquaculture.     

The dynamics of plant disease models with continuous and impulsive cultural control strategies

Plant disease mathematical models including continuous cultural control strategy and impulsive cultural control strategy are proposed and investigated. This novel theoretical framework could result in an objective criterion on how to control plant disease transmission by replanting of healthy plants and removal of infected plants. Firstly, continuous replanting of healthy plants and removing of infected plants is taken. The existence and stability of disease-free equilibrium and positive equilibrium are studied and continuous cultural control strategy is given. Secondly, plant disease model with impulsive replanting of healthy plants and removing of infected plants is also considered. Using Floquet's theorem and small amplitude perturbation, the sufficient conditions under which the infected plant free periodic solution is locally stable are obtained. Moreover, permanence of the system is investigated. Under certain parameter spaces, it is shown that a nontrivial periodic solution emerges via a supercritical bifurcation. Finally, our findings are confirmed by means of numerical simulations. The modeling methods and analytical analysis presented can serve as an integrating measure to identify and design appropriate plant disease control strategies.     

Antigen-antibody dissociation in Alzheimer disease: a novel approach to diagnosis

With the ever-increasing population of aged individuals at risk of developing Alzheimer's disease (AD), there is an urgent need for a sensitive, specific, non-invasive, and diagnostic standard. The majority of efforts have focused on auto-antibodies against amyloid-β (Aβ) protein, both as a potential treatment, and a reliable biomarker of AD pathology. Naturally occurring antibodies against Aβ are found in the CSF and plasma of patients with AD as well as healthy control subjects. To date, differences between diseased and control subjects have been highly variable. However, some of the antibody will be in preformed antigen–antibody complexes and the extent and nature of such complexes may provide a potential explanation for the variable results reported in human studies. Thus, measuring total amounts of antigen or antibody following unmasking is critical. Here, using a technique for dissociating antibody–antigen complexes, we found significant differences in serum antibodies to Aβ between AD and aged-matched control subjects. While the current study demonstrates the relevance of measuring total antibody, bound and unbound, against Aβ in AD, this technique may be applicable to diseases such as acquired immune deficiency syndrome and hepatitis B where determination of antigen and antibody levels are important for disease diagnosis and assessing disease progression.     

Tissue culture of ornamental pot plant: a critical review on present scenario and future prospects

Recent modern techniques of propagation have been developed which could help growers to meet the demand of the horticultural industry in the next century. An overview on the in vitro propagation via thin cell layer, meristem culture, regeneration via organogenesis and somatic embryogenesis is presented. Available methods for the transfer of genes could significantly simplify the breeding procedures and overcome some of the agronomic and environmental problems, which other wise would not be achievable through conventional propagation methods. The development and remarkable achievements with biotechnology in ornamental pot plants made during the three decades have been reviewed. The usefulness of the pot plants in commercial industry as well as propagation techniques, screening for various useful characteristics and selection of somaclonal variation is also discussed.     

A comparison of the LDL-cholesterol lowering efficacy of plant stanols and plant sterols over a continuous dose range: results of a meta-analysis of randomized, placebo-controlled trials

Purpose

To determine if plant stanols and plant sterols differ with respect to their low-density lipoprotein cholesterol (LDL-CH) lowering efficacies across a continuous dose range.

Methods

Dose-response relationships were evaluated separately for plant stanols and plant sterols and reductions in LDL-CH, using a first-order elimination function.

Results

Altogether, 113 publications and 1 unpublished study report (representing 182 strata) complied with the pre-defined inclusion and exclusion criteria and were included in the assessment. The maximal LDL-CH reductions for plant stanols (16.4%) and plant stanol ester (17.1%) were significantly greater than the maximal LDL-CH reductions for plant sterols (8.3%) and plant sterol ester (8.4%). These findings persisted in several additional analyses.

Discussion and conclusions

Intakes of plant stanols in excess of the recommended 2 g/day dose are associated with additional and dose-dependent reductions in LDL-CH, possibly resulting in further reductions in the risk of coronary heart disease (CHD).     

Coordination of a disubstituted alkene in a chelated d-metal-alkyl-alkene complex. Evidence for equilibrium between complexes with coordinated and free alkenes

Addition of (Cp*₂YH)₂ (4) to 2-methyl-1,4-pentadiene produced the yttrium-alkyl-alkene chelate complex Cp*₂YCH₂CH₂CH₂C(CH₃)=CH₂ (2) in which a disubstituted alkene is complexed to the metal center. Evidence for coordination of the alkene unit of 2 comes from the ¹H and ¹³C NMR chemical shifts of the vinyl units and from observation of nOe effects between Cp* protons and vinyl hydrogens. The disubstituted alkene ligand of 2 is weakly bound, and evidence for an equilibrium with substantial amounts of complex 3 with a free alkene was obtained from variable temperature ¹H NMR spectroscopy.     

Friends and foes: streptomycetes as modulators of plant disease and symbiosis

The ecological role of soil streptomycetes within the plant root environment is currently gaining increased attention. This review describes our recent advances in elucidating the complex interactions between streptomycetes, plants, pathogenic and symbiotic microorganisms. Streptomycetes play diverse roles in plant-associated microbial communities. Some act as biocontrol agents, inhibiting plant interactions with pathogenic organisms. Owing to the antagonistic properties of streptomycetes, they exert a selective pressure on soil microbes, which may not always be for plant benefit. Others promote the formation of symbioses between plant roots and microbes, and this is in part due to their direct positive influence on the symbiotic partner, expressed as, e.g., promotion of hyphal elongation of symbiotic fungi. Recently, streptomycetes have been identified as modulators of plant defence. By repressing plant responses to pathogens they facilitate root colonisation with pathogenic fungi. In contrast, other strains induce local and systemic resistance against pathogens or enhance plant growth. In conclusion, while streptomycetes have a clear potential of acting as biocontrol agents, care has to be taken to avoid strains that select for virulent pathogens or enhance disease development. We argue towards the use of an integrated screening approach in the search for efficient biocontrol agents, including assays on in vitro antagonism, plant growth, and disease suppression.     

Habitat fragmentation effects on fitness of plant populations – a review

Habitat fragmentation threatens the survival of many species and local populations. Habitat fragmentation has two major consequences: populations become more isolated and are reduced in size. Small compared with large populations have increased extinction risks because of different types stochasticity (e.g. genetic drift) and inbreeding, which can negatively affect the fitness of individuals or populations. Habitat fragmentation may also change the abiotic conditions of the surrounding landscape, which influences biotic interactions. This review gives an introduction to the theory of the effects of habitat fragmentation on mean fitness of plant populations. It intends to help bridge the gap between conservation biologists and conservation practitioners. The paper shortly introduces basic concepts of population biology, demography and genetics and cites relevant and new literature. Special attention is given to more common plant species, which have attracted far less conservation attention than rare species.     

用于肝脏疾病研究的人源化小鼠模型概述

肝脏疾病是危害人类健康的重要疾病之一,合适的小动物模型的缺乏在很大程度上制约了肝脏疾病的相关研究。人源化小鼠作为重要动物模型之一,在肝脏疾病的研究中有巨大的应用价值。本文对早期的uPA小鼠、FAH小鼠、TK-NOG小鼠和近年来的AFC8小鼠等几种应用较为广泛且有代表性的人源化小鼠模型及其在肝脏疾病研究中的应用进行了对比分析,阐述了它们各自的模型原理和优缺点,以期对人源化小鼠应用于人类肝脏疾病的研究具有较为直观的认识。     

Radioiodinated clioquinol as a biomarker for beta-amyloid: Zn complexes in Alzheimer's disease

Neocortical beta-amyloid (Abeta) aggregates in Alzheimer's disease (AD) are enriched in transition metals that mediate assembly. Clioquinol (CQ) targets metal interaction with Abeta and inhibits amyloid pathology in transgenic mice. Here, we investigated the binding properties of radioiodinated CQ ([(125)I]CQ) to different in vitro and in vivo Alzheimer models. We observed saturable binding of [(125)I]CQ to synthetic Abeta precipitated by Zn(2+) (K(d)=0.45 and 1.40 nm for Abeta(1-42) and Abeta(1-40), respectively), which was fully displaced by free Zn(2+), Cu(2+), the chelator DTPA (diethylene triamine pentaacetic acid) and partially by Congo red. Sucrose density gradient of post-mortem AD brain indicated that [(125)I]CQ concentrated in a fraction enriched for both Abeta and Zn, which was modulated by exogenous addition of Zn(2+) or DTPA. APP transgenic (Tg2576) mice injected with [(125)I]CQ exhibited higher brain retention of tracer compared to non-Tg mice. Autoradiography of brain sections of these animals confirmed selective [(125)I]CQ enrichment in the neocortex. Histologically, both thioflavine-S (ThS)-positive and negative structures were labeled by [(125)I]CQ. A pilot SPECT study of [(123)I]CQ showed limited uptake of the tracer into the brain, which did however, appear to be more rapid in AD patients compared to age-matched controls. These data support metallated Abeta species as the neuropharmacological target of CQ and indicate that this drug class may have potential as in vivo imaging agents for Alzheimer neuropathology.     

Trinuclear iridium and rhodium complexes: the solution to a puzzle involving the multiple coordination possibilities of 1,8-naphthyridine-2-one ligands

The multiple coordination possibilities of 1,8-naphthyridine-2-one (HOnapy) and 5,7-dimethyl-1,8-napthyridine-2-one (HOMe₂napy) ligands allow the synthesis of a variety of tri- di- and mononuclear complexes, showing fluxional behaviour and frequent exchange of the coordinated ML₂ fragments. Thus, reactions of [M₂(μ-OMe)₂(cod)₂] (cod = 1,5-cyclooctadiene) with HOnapy and HOMe₂napy yield the compounds of the general formula [M(μ-OR₂napy) (cod)]_n (M = Ir, R = Me (1a, 1b, H (2); M = Rh, R = Me (3a, 3b). They crystallise as inconvertible yellow (a) and purple/orange (b) forms and also show a puzzling behaviour in solution. X-ray diffraction studies on both forms (3a, 3b) and spectroscopic data reveal that the yellow forms are mononuclear complexes whilst the dark-coloured crystals contain dinuclear complexes. In solution, the nuclearity of the complexes depends on the solvent. In addition both types of complexes are fluxional. The mixed-ligand complexes [M₂(μ-OMe₂napy)₂(CO)₂(cod)] M = Ir (5), Rh (6) have been isolated and characterised; they are found to be intermediates in the synthesis of the trinuclear complexes [M₃(μ₃-OMe₂napy)₂(CO)₂(cod)₂]⁺ M = Rh (8), Ir (9). Reactions of [IrCl(CO)₂(NH₂-p-tolyl] with the complexes [Rh(μ-OR₂napy)(diolefin)]_n followed by addition of a poor donor anion is a general one-pot synthesis for the hetertrinuclear complexes [Rh₂Ir(μ₃-OR₂napy)₂(CO)₂(diolefin)₂]⁺ (R=Me, DIOLEFIN = cod (10), tetrafluorobenzo-barrelene (tfbb) (11), 2,5-norbornadiene (nbd) (12); R=H, DIOLEFIN=cod (13)). This synthesis follows a stepwise mechanism from the mononuclear to the trinuclear complexes in which mixed-ligand heterodinuclear complexes are involved as intermediates of the type [(diolefin)Rh(μ-OMe₂napy)₂Ir(CO)₂]. Heteronuclear complexes which possess the core [RhIr₂]³⁺, such as [RhIr₂(μ₃-OR₂napy)₂(CO)₂(cod)₂]BF₄ (R=Me (14), H (15)), result from the reaction of 1 or 2 with [Rh(CO)₂S_x]⁺ (S = solvent). The trinuclear complexes undergo two chemically reversible one-electron oxidation processes. The chemical oxidation of 10, 14 and 9 with silver salts gives the mixed-valence trinuclear radicals [Rh₂Ir(μ₃-OMe₂napy)₂(CO)₂(cod)₂]²⁺ (16), [RhIr₂(μ₃-OMe₂napy)₂(CO)₂(cod)₂]²⁺ (17) and [Ir₃(μ₃-OMe₂napy)₂(CO)₂(cod)₂]²⁺ (18), which have been isolated as the perchlorate and tetrafluoroborate salts. The EPR spectrum of 16 indicates that the unpaired electron is essentially in an orbital delocalised on the metals. The molecular structures of the complexes 3a, 3b, 6, 10b and 16a are described. Crystals of 3a are triclinic, P-1, with a = 9.7393(2), b = 14.0148(4), c = 16.0607(4) Å, α = 88.122(3), β = 83.924(3), γ = 87.038(3)°, Z = 4; 3b crystallises in the Pna2_i orthorhhombic space group, with a = 16.7541(3), B = 11.7500(8), c = 17.7508(7) Å, Z = 4; complex 6 is packed in the monoclinic space group P2_i/c, a = 9.6371(1), b = 11.8054(4), c = 27.2010(9) Å, β = 90.556(4)°, Z = 4; crystals of 10b are monoclinic, P2₁/n, with a = 17.546(7), b = 13.232(6), c = 17.437(8) Å, β = 106.18(1)°, Z = 4; crystals of 16a are triclinic, P-1, with a = 10.318(4), b = 12.562(6), C = 19.308(8) Å, α = 92.12(8), β = 97.65(9), γ = 90.68(5)°, Z = 2. The five different structures show the coordination versatility of the OMe₂napy molecule as ligand, which behaves as a N,N′-chelating (3a), bidentate N,O-donor (3b, 6), or as a tridentate N,N′,O-donor bridging ligand (10b, 16a).