Macrophomina phaseolina – Meloidogyne javanica disease complex in balsam (Impatiens balsamina): a new report

Balsam seedlings were inoculated with root-knot nematode Meloidogyne javanica Race-2 and Macrophomina phaseolina either individually or concomitantly, as well as sequentially with an interval of 15?days between the nematode or fungal inoculations to determine whether the interaction was concomitant or sequential. The greater reduction in plant growth characters was observed in the plants inoculated with M. javanica and M. phaseolina, either concomitantly or sequentially as compared to their individual inoculation. However, the highest reduction in plant growth characters were recorded in the plants inoculated with M. javanica Race-2 15?days prior to M. phaseolina followed by concomitant-inoculated M. javanica Race-2 and M. phaseolina, and M. phaseolina 15?days prior to M. javanica. The number of galls/root system and the reproduction factor of the root-knot nematode was reduced in the presence of root-rot fungus. The intensity of root-rot caused by M. phaseolina increased in the presence of root-knot nematode M. javanica as compared to when M. phaseolina was inoculated individually. Moreover, stem and collar-rot symptoms caused by M. phaseolina appeared only in the presence of root-knot nematode.     

Cadmium-induced early changes in O2 •−, H2O2 and antioxidative enzymes in soybean (Glycine max L.) leaves

Cadmium-induced initial changes in the production of reactive oxygen species (ROS) and antioxidant mechanism were investigated in soybean (Glycine max L. cv. Don Mario 4800 RR) leaves. Whole plants (WP) and plants without roots (PWR) were exposed to 0.0, 10.0 and 40.0 μM Cd for 0, 4, 6 and 24 h. Compared to PWR, a higher level of endogenous Cd in WP was associated with a lower oxidative stress measured in terms of lipid peroxidation. Furthermore, O₂ ^•− content decreased in the leaves of Cd-treated WP, whereas it increased in those of Cd-treated PWR. Although O₂ ^•− accumulation in PWR was associated with a decrease in superoxide dismutase (SOD) activity, O₂ ^•− diminution in WP leaves was not related to any increase in SOD activity. H₂O₂ content increased in the leaves of both Cd-treated WP and PWR, and it was concomitant with a corresponding decline in catalase (CAT) and ascorbate peroxidase (APX) activities. When diphenyl iodonium (DPI), an inhibitor of NADPH oxidase, was added, H₂O₂ content remained unchanged in Cd-treated WP, suggesting that NADPH oxidase does not participate in the early hours of Cd toxicity. Taken together, our results showed that early ROS evolution and oxidative damage were different in WP and PWR. This suggests that the response in soybean leaves during the early hours of Cd toxicity is probably modulated by the root.     

O2 sensitivity and H2 production activity of hydrogenases—A review

Hydrogenases are metalloproteins capable of catalyzing the interconversion between molecular hydrogen and protons and electrons. The iron–sulfur clusters within the enzyme enable rapid relay of electrons which are either consumed or generated at the active site. Their unparalleled catalytic efficiency has attracted attention, especially for potential use in H₂ production and/or fuel cell technologies. However, there are limitations to using hydrogenases, especially due to their high O₂ sensitivity. The subclass, called [FeFe] hydrogenases, are particularly more vulnerable to O₂ but proficient in H₂ production. In this review, we provide an overview of mechanistic and protein engineering studies focused on understanding and enhancing O₂ tolerance of the enzyme. The emphasis is on ongoing studies that attempt to overcome O₂ sensitivity of the enzyme while it catalyzes H₂ production in an aerobic environment. We also discuss pioneering attempts to utilize the enzyme in biological H₂ production and other industrial processes, as well as our own perspective on future applications.     

Cloning of AAC(3) and AAD(2″) genes fromAcinetobacter: differential expression in the host strain

The mechanism of resistance to gentamicin and tobramycin in a clinical isolate ofAcinetobacter baumannii, in which aminoglycoside-modifying enzymes were not detected, was investigated. For increase of the resistance gene product, DNA prepared from theA. baumannii isolate was cloned into pUC18 and introduced intoEscherichia coli by transformation. Gentamicin-resistant transformants were screened for aminoglycoside-modifying enzymes. This approach identified two genes encoding AAC(3) and AAD(2) activity, respectively. To determine whether both genes are expressed in the hostAcinetobacter strain, we extracted total cellular RNA from this strain, and Northern blots were hybridized with the cloned AAC(3) and AAD(2) structural genes. mRNA transcribed from the AAC(3) gene alone was detected. This shows that cloning a functional resistance gene is not sufficient in itself to investigate mechanisms of resistance in bacterial strains without detectable aminoglycoside-modifying activity. Furthermore, this study suggests a potential limitation of antibiotic resistance gene probes for studying mechanisms of resistance.     

Resonance Raman studies of the peroxotitanate(IV) complexes K2(Ti(O2)(SO4)2)·5H2O and K2(Ti(O2)(C2O4)2)·3H2O

The resonance Raman spectra of K₂(Ti(O₂)(SO₄)₂)·5H₂O and K₂(Ti(O₂)(C₂O₄)₂)·3H₂O are recorded. The results are consistent with the triangular structure of the peroxotitanium unit, Ti(O₂), with C_2ν symmetry. The ν(OO), ν_s(TiO) and ν_as(TiO) are observed around 890, 610 and 535 cm⁻¹, respectively. The resonance effects are shown to be associated with the 425 nm absorption band. This band is assigned to the O₂²⁻ → Ti(IV) charge-transfer transition. The calculated force constant values for the O₂²⁻ and TiO bonds are 320 and 275 N m⁻¹, respectively.     

Nitric Oxide Production by Necrotrophic Pathogen Macrophomina phaseolina and the Host Plant in Charcoal Rot Disease of Jute: Complexity of the Interplay between Necrotroph–Host Plant Interactions

M. phaseolina, a global devastating necrotrophic fungal pathogen causes charcoal rot disease in more than 500 host plants. With the aim of understanding the plant-necrotrophic pathogen interaction associated with charcoal rot disease of jute, biochemical approach was attempted to study cellular nitric oxide production under diseased condition. This is the first report on M. phaseolina infection in Corchorus capsularis (jute) plants which resulted in elevated nitric oxide, reactive nitrogen species and S nitrosothiols production in infected tissues. Time dependent nitric oxide production was also assessed with 4-Amino-5-Methylamino-2′,7′-Difluorofluorescein Diacetate using single leaf experiment both in presence of M. phaseolina and xylanases obtained from fungal secretome. Cellular redox status and redox active enzymes were also assessed during plant fungal interaction. Interestingly, M. phaseolina was found to produce nitric oxide which was detected in vitro inside the mycelium and in the surrounding medium. Addition of mammalian nitric oxide synthase inhibitor could block the nitric oxide production in M. phaseolina. Bioinformatics analysis revealed nitric oxide synthase like sequence with conserved amino acid sequences in M. phaseolina genome sequence. In conclusion, the production of nitric oxide and reactive nitrogen species may have important physiological significance in necrotrophic host pathogen interaction.     

Limiting mechanisms in the regeneration of the Chilean matorral – Experiments on seedling establishment in burned and cleared mesic sites

The Chilean matorral is characterized by multispecific shrub clumps in dry areas but has a continuous canopy in wetter sites. It has been hypothesized that this difference is due to easier recolonization of open patches by shrub seedlings under more mesic conditions. Within the mesic range of the matorral we designed a field experiment to compare shrub seedling emergence, growth, and survival under the closed canopy of a secondary forest versus three types of open patches: burned, cleared of shrubs but with a herbaceous layer present, and clear without a herbaceous layer. After the first summer, survival of Quillaja saponaria seedlings was 75% in the burned site, 30% in the cleared patch without herbaceous vegetation, and 15% with herbaceous vegetation present, whereas there was 0% survival under the secondary forest canopy. After eight years, the percentages had dropped to: 22%, 12% and 3%, respectively. These results contrast strongly with the seedling establishment patterns in drier areas of the matorral where early seedling survival is higher under the shade of large shrubs. In the experimental mesic sites, seedlings did best on the burned site, not only in terms of survival, but also in terms of growth. After one year, seedling mean height was 10.2 cm in the burned site, whereas 3.8 cm and 5.3 cm in the cleared patches without and with herbaceous respectively. After eight years, mean height differences between treatments had increased further: 147.7 cm in the burned site, 40.3 cm in the cleared patch without herbaceous cover and 13 cm in the cleared patch with herbs. Our results indicate that the facilitative effect of nurse shrubs on seedling establishment found in dry ranges of the matorral is less important in more mesic sites. This difference may explain the continuous shrub cover in relatively mesic areas as opposed to the characteristic patchy structure of the matorral in its drier range.     

Phylogeny of the Alismatales (Monocotyledons) and the relationship of Acorus (Acorales?)

A phylogenetic analysis of the early branching lineages of the monocotyledons is performed using data from two plastid genes (rbcL and matK), five mitochondrial genes (atp1, ccmB, cob, mttB and nad5) and morphology. The complete matrix includes 93 terminals representing Acorus, the 14 families currently recognized within Alismatales, and numerous lineages of monocotyledons and other angiosperms. Total evidence analysis results in an almost completely resolved strict consensus tree, but all data partitions, genomic as well as morphological, are incongruent. The effects of RNA editing and potentially processed paralogous sequences are explored and discussed. Despite a decrease in incongruence length differences after exclusion of edited sites, the major data partitions remain significantly incongruent. The 14 families of Alismatales are all found to be monophyletic, but Acorus is found to be included in Alismatales rather than being the sister group to all other monocotyledons. The placement is strongly supported by the mitochondrial data, atp1 in particular, but it cannot be explained as an artifact caused by patterns of editing or by sampling of processed paralogues.     

Microsolvation and hydration enthalpies of CaC2O4(H2O) n (n = 0-16) and C2O4 2-(H2O) n (n = 0-14): an ab initio study

We studied hydrated calcium oxalate and its ions at the restricted Hartree–Fock RHF/6-31G* level of theory. Performing a configurational search seems to improve the fit of the HF/6-31G* level to experimental data. The first solvation shell of calcium oxalate contains 13 water molecules, while the first solvation shell of oxalate ion is formed by 14 water molecules. The first solvation shell of Ca(II) is formed by six water molecules, while the second shell contains five. At 298.15 K, we estimate the asymptotic limits (infinite dilution) of the total standard enthalpies of hydration for Ca(II), oxalate ion and calcium oxalate as ?480.78, –302.78 and –312.73 kcal mol^?1, resp. The dissociation of hydrated calcium oxalate is an endothermic process with an asymptotic limit of +470.84 kcal mol^?1.

Lack of correlation between TBARS production and PUFA degradation during incubation of membrane erythrocytes in an OH⋅ (Fe2+/H2O2) generator system

We investigated the effects of an OH^⋅ (Fe²⁺/H₂O₂) generator system of erythrocyte membrane, particularly the time-course of lipid peroxidation as estimated by measurement of conjugated dienes, thiobarbituric reactive substances (TBARS), lipofuscin-like pigments, and α-tocopherol. Polyunsaturated fatty acids (PUFAs), especially arachidonic acid (20∶4 ω 6) and docosahexenoic acid (22∶6 ω 3), were also measured. Erythrocyte membranes were suspended in phosphate buffer containing Fe²⁺ (200 μM) and H₂O₂ (1.42 mM), and incubated in a shaking water bath at 37°C. Initially, there was an increase in TBARS and lipofuscin-like pigments, two well-known end products of PUFA oxidative degradation, whereas PUFAs remained unchanged (incubation time: 1 h). After two or more hours of incubation, marked lipid peroxidation was noted, with the appearance of conjugated dienes and a decrease of PUFAs, indicating that lipid peroxidation had occurred after a lag phase during which TBARS were not produced from PUFAs. This suggests that another OH^⋅ target was involved.     

Development and fecundity of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on different soybean cultivars

The life history of Spodoptera exigua was studied under laboratory conditions at temperature of 25°C ± 1°C, relative humidity (RH) of 60% ± 5% and a photoperiod of 16:8 h (Light:Dark) on nine soybean (Glycine max L.) cultivars: 032, 033, Hill, M4, M7, M9, M11, TMS and Zan. Larval and pupal development times were longest on M7 cultivar (14.09 ± 0.078 and 7.78 ± 0.090 days) and shortest on 033 cultivar (11.98 ± 0.054 and 7.033 ± 0.090 days). The longest and shortest female and male longevities were observed on Hill and Zan cultivars, respectively. The results showed that the whole life span varied from 32.80 ± 0.89 to 37 ± 0.98 days for females and from 33.3 ± 0.66 to 38.74 ± 0.95 days for males. The highest daily fecundity was obtained on M9 (102. 38 eggs), and the lowest on Hill (75.87 eggs). Mean total fecundity per female during adult life was highest on 033 (1156.20 eggs) and lowest on M7 cultivars (841.68 eggs). Clustering analysis of the biological parameters of S. exigua confirmed that 033 and Hill cultivars were the susceptible and the resistant cultivars, respectively.     

Commercial production of β-glucuronidase (GUS): a model system for the production of proteins in plants

We have generated transgenic maize seed containing -glucuronidase(GUS) for commercial production. While many other investigators have demonstrated the expression of GUS as a scoreable marker, this is one of the first cases where a detailed characterization of the transgenic plants and the protein were performed which are necessary to use this as a commercial source of GUS. The recombinant -glucuronidase was expressed at levels up to 0.7% of water-soluble protein from populations of dry seed, representing one of the highest levels of heterologous proteins reported for maize. Southern blot analysis revealed that one copy of the gene was present in the transformant with the highest level of expression. In seeds, the majority of recombinant protein was present in the embryo, and subcellular localization indicated that the protein was dispersed throughout the cytoplasm. The purified recombinant -glucuronidase (GUS) was compared to native -glucuronidase using SDS-PAGE and western blot analysis. The molecular mass of both the recombinant and native enzymes was 68 000 Da. N-terminal amino acid sequence of the recombinant protein was similar to the sequence predicted from the cloned Escherichia coli gene except that the initial methionine was cleaved from the recombinant GUS. The recombinant and native GUS proteins had isoelectric points (pI) from 4.8 to 5.0. The purified proteins were stable for 30 min at 25, 37, and 50 ° C. Kinetic analysis of the recombinant and native GUS enzymes using 4-methylumbelliferyl glucuronide (MUG) as the substrate was performed. Scatchard analysis of these data demonstrated that the recombinant enzyme had a K_m of 0.20 mM and a V_max of 0.29 mM MUG per hour, and the native enzyme had a K_m and V_max of 0.21 mM and 0.22 mM/h respectively. Using D-saccharic acid 1,4-lactone, which is an inhibitor of -glucuronidase, the K_i of the native and recombinant enzymes was determined to be 0.13 mM. Thus, these data demonstrate that recombinant GUS is functionally equivalent to native GUS. We have demonstrated the expression of high levels of GUS can be maintained in stable germlines and have used an efficient recovery system where the final protein product, GUS, has been successfully purified. We describe one of the first model systems for the commercial production of a foreign protein which relies on plants as the bioreactor.     

Simultaneous detection of NADPH consumption and H2O2 production using the Ampliflu™ Red assay for screening of P450 activities and uncoupling

Applied Microbiology and Biotechnology - Cytochrome P450s belong to a large and diverse group of heme-containing enzymes. These monooxygenases catalyze the incorporation of a single atom of...     

Weak coherent radiation of OH and ortho- H2O space masers as a carrier in biocommunication: the ortho/para-conversion of H2O spin isomers?

A conception of biocommunication based on the principle of radiophysics stating that the carrier modulation takes place at the resonance frequency in the transmission-receiver system has been substantiated and proved. The coherent radiation of space OH-masers (1.6-1.7 GHz) and ortho-H2O-maser (22.3 GHz) is proposed as a source of the carrier frequency. The narrow lines of rotational transition of H2O and OH molecules in liquid water were proposed to be considered as an analog of selective resonances of transmitter and receiver in radiocommunication. The possibility of the ortho-para conversion of H2O spin isomers, induced by weak electromagnetic fields, is discussed.     

Roles of Protein Kinase C δ in the Accumulation of P53 and the Induction of Apoptosis in H 2 O 2 -treated Bovine Endothelial Cells

To clarify the signaling pathways of oxidative stress-induced apoptosis in bovine aortic endothelial cells (BAEC), we treated cells with 1 mM H 2 O 2 and investigated the roles of protein kinase C &#105 (PKC &#105 ) and Ca 2+ in the accumulation of p53 associated with apoptosis. The treatment of cells with H 2 O 2 caused the accumulation of p53, which was inhibited by rottlerin (a PKC &#105 inhibitor) but not by BAPTA-AM (an intracellular Ca 2+ chelator). PKC &#105 itself was activated through the phosphorylation at tyrosine residues. H 2 O 2 induced the release of cytochrome c and the activation of caspases 3 and 9, and these apoptotic signals were inhibited by rottlerin and BAPTA-AM. These results suggest that PKC &#105 contributes to the accumulation of p53 and that Ca 2+ plays a role in downstream signals of p53 leading to apoptosis in H 2 O 2 -treated BAEC.     

What is the economic threshold of soybean aphids (Hemiptera: Aphididae) in enemy-free space?

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a serious pest of soybean, Glycine max (L.) Merr., in the North Central United States. Current management recommendations rely on the application of insecticides based on an economic threshold (ET) of 250 aphids per plant. Natural enemies are important in slowing the increase of aphid populations and can prevent them from reaching levels that can cause economic losses. However, biological control of A. glycines is inconsistent and can be affected negatively by the intensity of agricultural activity. We measured the impact of a natural-enemy-free environment on the capacity of the current ET to limit yield loss. In 2008 and 2009, caged microplots were assigned to one of three treatments: plants kept aphid-free (referred to as the control), plants that experienced a population of 250 aphids per plant (integrated pest management [IPM]), and plants that experienced unlimited aphid population growth (unlimited). The population growth rate of aphids in the unlimited treatment for the 10 d after the application of insecticides to the IPM treatment was calculated using linear regression. The linear equation was solved to determine the mean number of days between the ET and the EIL for an aphid population in absence of predators. The number of days was determined to be 6.97 +/- 1.11 d. The 2-yr average yield for the IPM treatment was 99.93% of the control treatment. Our study suggests the current soybean aphid ET of 250 aphids per plant can effectively protect yield even if the impact of natural enemies is reduced.     

Speciation of dimethyltin(IV) – and trimethyltin(IV) – carbocysteinate and – glutamate systems in aqueous media

Abstract

The formation of complex species in the dimethyltin(IV) and trimethyltin(IV)-carboxymethyl-L-cysteinate (carbocysteinate) systems in NaCl_aq, at different ionic strengths, and in a multicomponent Na⁺, K⁺, Ca²⁺ ,Mg²⁺, Cl^? and SO₄^2-? medium representative of the seawater major composition, is discussed. Experimental results give evidence for the formation of the following species (L = carbocysteinate): [(CH₃)₂Sn(L)]⁰, [(CH₃)₂Sn(HL)]⁺, [(CH₃)₂Sn(OH)(L)]^?, [(CH₃)₂Sn(OH)₂(L)]^2? in the DMT–CCYS system, and [(CH₃)₃Sn(HL)]⁰, [(CH₃)₃Sn(L)]^? and [(CH₃)₃Sn(OH)(L)]^2? in the TMT-CCYS system. The ionic strength dependence of formation constants was taken into account by an extended Debye Hückel type equation and by the SIT (Specific ion Interaction Theory). Measurements were carried out also on the dimethyltin(IV)-glutamate and trimethyltin(IV)-glutamate systems in NaCl_aq, owing the strict similarity of glutamate and carbocysteinate. Results obtained show the formation of complex species having the same stoichiometry as those formed in the DMT- and TMT-carbocysteinate systems, with very similar stability, confirming that carbocysteinate behaves as a dicarboxylic amino acid without involving the sulfur-bridge potential binding site in metal coordination.