Attraction of the predator,Harmonia axyridis (Coleoptera: Coccinellidae), to its prey,Myzus persicae (Hemiptera: Aphididae), feeding on Chinese cabbage

The predatory multicolored Asian lady beetle, Harmonia axyridis, was attracted to volatiles released from Chinese cabbage infested by the green peach aphid, Myzus persicae, in T-tube olfactometer choice tests. However, lady beetle adults and larvae did not respond to clean air, Chinese cabbage alone or green peach aphid alone. Of different prey densities, H. axyridis adults were most attracted to Chinese cabbage infested by 60 M. persicae adults after 24 h. However, H. axyridis larvae were not attracted to Chinese cabbage infested by M. persicae. Mechanically damaged Chinese cabbage attracted neither lady beetle adults nor larvae. Predatory adults were attracted to 60 M. persicae adults after 24 and 48 h, and to 90 M. persicae adults after 12 h, suggesting that the predatory response depends on the prey density. Lady adult beetles did not prefer the volatiles induced by Diamondback moth, Plutella xylostella, indicating that specific host insect specificity attracts respective natural enemies. It can be explained that the volatile compounds emitted from the host plant as a result of herbivore attack preferred by the specific insect species.     

Effects of varying temperature on the reproduction and damage potential of Heterodera schachtii to Chinese cabbage (Brassica rapa pekinensis)

Heterodera schachtii is a well-known, destructive pathogen of Chinese cabbage (Brassica rapa pekinensis) in Korea, and several studies have attempted to find a potential control measure against it. This study is the first to investigate the effects of varying temperature on the reproduction and damage potential of H. schachtii to Chinese cabbage. Chinese cabbage plants were inoculated with H. schachtii at different densities (1, 2, or 4 juveniles per gram of soil) and grown under three temperature regimes: constant (15, 20, or 25 °C), increasing (10, 14, and 18 °C), and fluctuating (positive, 16.7–22.0 °C; negative, 21.5–11.5 °C). At a constant temperature after 30 days of inoculation, both Chinese cabbage and H. schachtii performed best at 20 °C. However, after 60 days of inoculation, H. schachtii had a significantly higher population at 20 °C, whereas cabbage growth was best at 25 °C. With increasing temperature, the numbers of cysts and females did not change significantly, and reached maxima at an initial temperature of 14 °C. However, the number of leaves and weights of the Chinese cabbage plants significantly differed at 14 °C. Under fluctuating temperatures, temperature decreases reduced the H. schachtii population.     

The effect of Achyranthes japonica extract on larval survival and development and oviposition behavior of Plutella xylostella L. (Lepidoptera: Plutellidae)

The extract of Achyranthes japonica was tested for effects on larval survival and development and the oviposition behavior of the diamondback moth, Plutella xylostella L. Chinese cabbage dipped in A. japonica extract solution showed 51–80% antifeedant activity for 5 days against P. xylostella larvae, and more larvae were also on untreated cabbage leaves 24 h after release. The mortality of P. xylostella larvae increased proportionally to the duration of dipping time in the extract, and both pupation and emergence rates of larvae feeding only on treated cabbage were lower than those for larvae raised on untreated or with a choice of cabbage. The 20-hydroxyecdysone (20E) concentration in leaves was approximately 549, 1232, 1275, and 1426 μg/g at 6, 12, 24, and 48 h after dipping treatment, respectively. Notably, naive females laid more eggs on untreated cabbage than on treated cabbage, and females from larvae raised on treated Chinese cabbage also preferred the non-treated leaves. Our results are in contrast to those from earlier studies using various insect models that confirmed most females prefer to lay eggs on the host type that was eaten in the larval stage (Hopkins host selection principle). Cabbage dipped in the A. japonica solution for 24 h caused 59% larval mortality and inhibited both pupation and emergence rates of the larvae when exposed to plants 15 and 22 days after planting in the field, with the 20E concentration in the treated cabbage leaves at 1600.9 ± 122.36 and 1386.8 ± 24.69 μg/g, respectively. Therefore, the biological effectiveness could be attributed to the 20E in the treated cabbage leaves.     

Proteomics analysis of proteins in green alga Haematococcus lacustris (Chlorophyceae) expressed under combined stress of nitrogen starvation and high irradiance

This study is aimed at identifying the proteins that are up-regulated during astaxanthin accumulation in Haematococcus lacustris. For this H. lacustris cells were cultivated in photobioreactors under normal light irradiance of 40 μE m^?2 s^?1 for 6 days and then induced to accumulate astaxanthin for 3 days further by exposure to continuous high irradiance of 200 μE m^?2 s^?1 with fluorescent lamps as light source after the cells reached the stationary phase in a nitrogen-depleted condition. Under this condition, the average astaxanthin content per cell increased from 91 mg/l up to 406 mg/l after 3 days of induction. The proteomics data from a two-dimensional electrophoretic comparison demonstrated that a combination of nitrogen source depletion and 1 h high light have significantly changed the pattern of protein expression in H. lacustris. A total of 49 protein spots were picked after 1 h of stress induction. They consisted of 13 down-regulated proteins and 36 up-regulated proteins. Fifteen proteins which had highly up-regulated expression were further analyzed by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The results will point toward interesting proteins that can be pursued for further analysis of astaxanthin biosynthesis pathway.     

Contrast Enhancement on Cone-Beam Breast-CT for Discrimination of Breast Cancer Immunohistochemical Subtypes

PURPOSE: To evaluate whether contrast enhancement on cone-beam breast-CT (CBBCT) could aid in discrimination of breast cancer subtypes and receptor status. METHODS: This study included female patients age >40 years with malignant breast lesions identified on contrast-enhanced CBBCT. Contrast enhancement of malignant breast lesions was standardized to breast fat tissue contrast enhancement. All breast lesions were approved via image-guided biopsy or surgery. Immunohistochemical staining was conducted for expression of estrogen (ER), progesterone (PR), human epidermal growth factor receptor-2 (HER2) and Ki-67 index. Contrast enhancement of breast lesions was correlated with immunohistochemical breast cancer subtypes (Luminal A, Luminal B, HER2 positive, triple negative), receptor status and Ki-67 expression. RESULTS: Highest contrast enhancement was seen for Luminal A lesions (93.6 HU) compared to Luminal B lesions (47.6 HU, P = .002), HER2 positive lesions (83.5 HU, P = .359) and triple negative lesions (45.3 HU, P = .005). Contrast enhancement of HER2 positive lesions was higher than Luminal B lesions (P = .044) and triple negative lesions (P = .039). No significant difference was evident between Luminal B and triple negative lesions (P = .439). Lesions with high Ki-67 index showed lower contrast enhancement than those with low Ki-67 index (P = .0043). ER, PR and HER2 positive lesions demonstrated higher contrast enhancement than their receptor negative counterparts, although differences did not reach statistical significance (P = .1714; P = .3603; P = .2166). CONCLUSIONS: Contrast enhancement of malignant breast lesions on CBBCT correlates with immunohistochemical subtype and proliferative potential. Thereby, CBBCT might aid in selecting individualized treatment strategies for breast cancer patients based on pre-operative imaging.     

Ultrastructural studies of Phellinus sulphurascens infection of Douglas-fir roots and immunolocalization of host pathogenesis-related proteins

Interactions between roots of Douglas-fir (DF; Pseudotsuga menziesii) seedlings and the laminated root rot fungus Phellinus sulphurascens were investigated using scanning and transmission electron microscopy and immunogold labelling techniques. Scanning electron micrographs revealed that P. sulphurascens hyphae colonize root surfaces and initiate the penetration of root epidermal tissues by developing appressoria within 2 d postinoculation (dpi). During early colonization, intra- and intercellular fungal hyphae were detected. They efficiently disintegrate cellular components of the host including cell walls and membranes. P. sulphurascens hyphae penetrate host cell walls by forming narrow hyphal tips and a variety of haustoria-like structures which may play important roles in pathogenic interactions. Ovomucoid–WGA (wheat germ agglutinin) conjugated gold particles (10 nm) confirmed the occurrence and location of P. sulphurascens hyphae, while four specific host pathogenesis-related (PR) protein antibodies conjugated with protein A–gold complex (20 nm) showed the localization and abundance of these PR proteins in infected root tissues. A thaumatin-like protein and an endochitinase-like protein were both strongly evident and localized in host cell membranes. A DF-PR10 protein was localized in the cell walls and cytoplasm of host cells while an antimicrobial peptide occurred in host cell walls. A close association of some PR proteins with P. sulphurascens hyphae suggests their potential antifungal activities in DF roots.     

Relative suitability of the common pistachio psyllid,Agonoscena pistaciae (Hemiptera: Aphalaridae), as prey for the two-spotted ladybird,Adalia bipunctata (Coleoptera: Coccinellidae)

The suitability of Agonoscena pistaciae Burckhardt & Lauterer as a prey for Adalia bipunctata (Linnaeus) was evaluated by studying the predator’s development and reproduction on this species in comparison to reference diets of nymphs of Myzus persicae (Sulzer) and eggs of Ephestia kuehniella Zeller. Both larval and adult A. bipunctata fed voraciously on A. pistaciae. The development time of the ladybird was shorter when fed on M. persicae and A. pistaciae and longer on E. kuehniella. The survival rate was 87% on M. persicae and 85% on A. pistaciae, both significantly greater than on E. kuehniella eggs (63%). The ladybirds were heaviest at eclosion and their fecundity was higher on M. persicae than on A. pistaciae or E. kuehniella. Both the aphid and psyllid diets yielded higher R₀, r_m values and lower T and DT values than E. kuehniella eggs. Based on total development time, immature survival and adult fecundity, the relative suitability for A. bipunctata was M. persicae > A. pistaciae > E. kuehniella. When ladybirds were reared on psyllids, they showed no preference between aphid or psyllid diets, but when raised on M. persicae, they preferred an aphid diet. A field experiment showed that A. bipunctata preferred to oviposit on pistachio trees at a height of 150–200 cm, i.e. towards the top. The results indicate that A. pistaciae constitutes a complete food for A. bipunctata, supporting both completed development and successful reproduction.     

Effect of crude oil petroleum hydrocarbons on protein expression of the prawn Macrobrachium borellii

Hydrocarbon pollution is a major environmental threat to ecosystems in marine and freshwater environments, but its toxicological effect on aquatic organisms remains little studied. A proteomic approach was used to analyze the effect of a freshwater oil spill on the prawn Macrobrachium borellii. To this aim, proteins were extracted from midgut gland (hepatopancreas) of male and female prawns exposed 7 days to a sublethal concentration (0.6 ppm) of water-soluble fraction of crude oil (WSF). Exposure to WSF induced responses at the protein expression level. Two-dimensional gel electrophoresis (2-DE) revealed 10 protein spots that were differentially expressed by WSF exposure. Seven proteins were identified using MS/MS and de novo sequencing. Nm23 oncoprotein, arginine methyltransferase, fatty aldehyde dehydrogenase and glutathione S-transferase were down-regulated, whereas two glyceraldehyde-3-phosphate dehydrogenase isoforms and a lipocalin-like crustacyanin (CTC) were up-regulated after WSF exposure. CTC mRNA levels were further analyzed by quantitative real-time PCR showing an increased expression after WSF exposure. The proteins identified are involved in carbohydrate and amino acid metabolism, detoxification, transport of hydrophobic molecules and cellular homeostasis among others. These results provide evidence for better understanding the toxic mechanisms of hydrocarbons. Moreover, some of these differentially expressed proteins would be employed as potential novel biomarkers.     

Formulation of a soil biofungicide for control of damping-off of Chinese cabbage (Brassica chinensis) caused by Rhizoctonia solani

A granulate biofungicide named PBGG was developed by combining Pseudomonas boreopolis with Brassica seed pomace, glycerin and sodium alginate. Application of 1.0% (w/w) of PBGG to the soil infested with Rhizoctonia solani AG-4 significantly reduced the percentage of colonization of cabbage seeds by the pathogen and stimulated proliferations of actinomycetes. Among Streptomyces populations, Streptomyces padanus (strain SS-07) and Streptomyces xantholiticus (strain SS-09) were the two most effective strains with strong antagonistic effects to R. solani. Application of 1% (w/w) PBGG in soil significantly increased population densities of S. padanus and S. xantholiticus. Treating soil with S. padanus (strain SS-07) or S. xantholiticus (strain SS-09) alone or in combination with 1% (w/w) PBGG significantly reduced the percentage of colonization of cabbage seeds by R. solani, compared to untreated controls. S. padanus was the most effective agent in reducing the percentage of seed colonization by the pathogen. Results of greenhouse tests showed that the most effective treatment was the amendment of pathogen-infested soil by S. padanus + 1% (w/w) PBGG which resulted in a disease incidence of 6.5–8.6%, compared to 27.8–31.7% for the treatment of S. xantholiticus + 1% (w/w) PBGG, 36.9–38.6% for the treatment of 1% (w/w) PBGG alone, and 61.8–64.8% for the treatment of control (unamended soil). Results of greenhouse and field tests also showed that soil amendment of 1% (w/w) PBGG alone or 1% (w/w) PBGG mixed with S. padanus (strain SS-07) or S. xantholiticus (strain SS-09) was not harmful to seed germination of Chinese cabbage. The study suggests that amendment of R. solani infested soil with S. padanus + 1% (w/w) PBGG prior to sowing is an effective method for control of damping-off of Chinese cabbage.     

Differential gel electrophoresis (DIGE) to quantitatively monitor early symbiosis- and pathogenesis-induced changes of the Medicago truncatula root proteome

Symbiosis- and pathogenesis-related early protein induction patterns in the model legume Medicago truncatula were analysed with two-dimensional differential gel electrophoresis. Two symbiotic soil microorganisms (Glomus intraradices, Sinorhizobium meliloti) were used in single infections and in combination with a secondary pathogenic infection by the oomycete Aphanomyces euteiches. Proteomic analyses performed 6 and 24 h after inoculations led to identification of 87 differentially induced proteins which likely represent the M. truncatula root ‘interactome’. A set of proteins involved in a primary antioxidant defense reaction was detected during all associations investigated. Symbiosis-related protein induction includes a typical factor of early symbiosis-specific signalling (CaM-2), two Ran-binding proteins of nucleocytoplasmic signalling, and a set of energy-related enzymes together with proteins involved in symbiosis-initiated C- and N-fixation. Pathogen-associated protein induction consists of mainly PR proteins, Kunitz-type proteinase inhibitors, a lectin, and proteins related to primary carbohydrate metabolism and phytoalexin synthesis. Absence of PR proteins and decreased pathogen-induced protein patterns during mixed symbiotic and pathogenic infections indicate bioprotective effects due to symbiotic co-infection. Several 14-3-3 proteins were found as predominant proteins during mixed infections. With respect to hormone-regulation, A. euteiches infection led to induction of ABA-related pathways, while auxin-related pathways are induced during symbiosis.     

Wheat quality related differential expressions of albumins and globulins revealed by two-dimensional difference gel electrophoresis (2-D DIGE)

Comparative proteomics analysis offers a new approach to identify differential proteins among different wheat genotypes and developmental stages. In this study, the non-prolamin expression profiles during grain development of two common or bread wheat cultivars (Triticum aestivum L.), Jing 411 and Sunstate, with different quality properties were analyzed using two-dimensional difference gel electrophoresis (2-D DIGE). Five grain developmental stages during the post-anthesis period were sampled corresponding to the cumulative averages of daily temperatures (°C: 156 °C, 250 °C, 354 °C, 447 °C and 749.5 °C). More than 400 differential protein spots detected at one or more of the developmental stages of the two cultivars were monitored, among which 230 proteins were identified by MS. Of the identified proteins, more than 85% were enzymes possessing different physiological functions. A total of 36 differential proteins were characterized between the two varieties, which are likely to be related to wheat quality attributes. About one quarter of the proteins identified expressed in multiple spots with different pIs and molecular masses, implying certain post-translational modifications (PTMs) of proteins such as phosphorylations and glycosylations. The results provide new insights into biochemical mechanisms for grain development and quality.     

Improved production of two expansin-like proteins in Pichia pastoris and investigation of their functional properties

The genes encoding expanin-like proteins from Trichoderma reesei (TrSwo1) and Bacillus subtilis (BsEXLX1) were successfully expressed in Pichia pastoris. The yields of two recombinant proteins were significantly improved by the use of PMSF (phenylmethylsulfonyl fluoride) and a commercial protease inhibitor cocktail. Under the optimum culture conditions, the highest TrSwo1/BsEXLX1 expression level reached was approximately 120/860 mg l⁻¹, which was almost 2.4/86-fold as much as the highest expression level in other host cells. Purified BsEXLX1/TrSwo1 displayed synergism in cellulose hydrolysis with endoglucanase, and the maximum amount of reducing sugars released was almost 2.0/2.5-fold as high as those in reaction mixtures without expansin-like proteins. The synergistic effect reached the maximum level when 1 mg of target protein per g of filter paper was loaded. Both proteins exhibited relatively high thermal stability at temperatures of 50, 70 and 90 °C, and retained more than 45% residual activities after 1 h of pre-incubation at 100 °C, suggesting remarkable heat tolerance. They also showed resistance to denaturation by urea and SDS. Under several enzymatic hydrolysis conditions, the synergistic activity of TrSwo1 was higher than that of BsEXLX1, indicating stronger disrupting activity of TrSwo1 on cellulose than BsEXLX1. This is the first study to report high-efficient expression and unreported properties of BsEXLX1/TrSwo1.     

Influence of host plant nitrogen fertilization on hemolymph protein profiles of herbivore Spodoptera exigua and development of its endoparasitoid Cotesia marginiventris

Nitrogen has complex effects on plant–herbivore–parasitoid tritrophic interactions. The negative effects of low nitrogen fertilization in host plants on insect herbivores can be amplified to the higher trophic levels. In the present study, we examined the impact of varying nitrogen fertilization (42, 112, 196, and 280 ppm) of cotton plants (Gossypium hirsutum L.) on the interactions between the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), and the hymenopteran endoparasitoid Cotesia marginiventris (Cresson) (Hymenoptera: Braconidae). We predicted that the development and fitness of C. marginiventris would be adversely affected by low host plant nitrogen fertilization through the herbivore S. exigua. The percentage of C. marginiventris offspring developing to emerge and spin a cocoon, and total mortality of parasitized S. exigua larvae were unaffected by nitrogen level. The developmental time of C. marginiventris larvae in S. exigua larvae feeding on low (42 ppm) nitrogen cotton plants was approximately 30% longer than that of those feeding on higher (112, 196, and 280 ppm) nitrogen plants. Parasitoid size (length of right metathoracic tibia), a proxy for fitness, of C. marginiventris males was positively affected by nitrogen level. Total amounts of S. exigua hemolymph proteins were not affected by nitrogen level, but were reduced by parasitism by C. marginiventris. Two proteins with molecular weights of ca. 84 and 170 kDa dominated the S. exigua larval hemolymph proteins. Concentrations of the 170 kDa hemolymph protein were unaffected by nitrogen treatment, but parasitism reduced concentrations of the 170 kDa protein. Concentrations of the 84 kDa protein, on the other hand, were interactively affected by parasitism and nitrogen treatment: higher nitrogen fertilization (112, 196, and 280 ppm) increased protein concentrations relative to the 42 ppm treatment for unparasitized S. exigua larvae, whereas nitrogen treatment had no effects on parasitized larvae. For S. exigua larvae feeding on 42 ppm nitrogen plants, parasitism increased concentration of the 84 kDa protein, while for those feeding on 112, 196, and 280 ppm nitrogen plants, parasitism decreased concentrations of the protein. Possible mechanisms and ecological consequences for the extended development of C. marginiventris on S. exigua hosts grown on low-nitrogen plants are discussed.     

Differential protein expression for geothermal Agrostis scabra and turf-type Agrostis stolonifera differing in heat tolerance

Heat stress is a major factor limiting the growth of cool-season grasses in warm climatic regions by affecting many physiological processes, including protein metabolism. Protein degradation often occurs with increasing temperatures, but certain specific proteins such as heat shock proteins (HSPs) may be induced or enhanced in their expression under supraoptimal temperatures. The objectives of this study were to determine the critical temperature that causes protein induction or degradation in two Agrostis grass species differing in heat tolerance and to compare protein profiles between the two species under different temperature regimes. Plants of heat-tolerant Agrostis scabra and two cultivars of heat-sensitive Agrostis stolonifera (‘L-93’ and ‘Penncross’) were exposed to constant day/night temperatures of 20, 30, 35, 40, or 45 °C for 14 d. Leaf photochemical efficiency (Fv/Fm), chlorophyll and carotenoid contents, and soluble protein content declined with increasing temperatures. The decreases were the least severe for A. scabra, intermediate for ‘L-93’, and the most severe for ‘Penncross’, indicating interspecific and intraspecific variations in heat tolerance in Agrostis species. Protein degradation was observed at 30–45 °C in both cultivars of A. stolonifera, and at 40–45 °C in A. scabra.HSPs were induced or enhanced at 35–45 °C in ‘L-93’ and A. scabra, and at 40–45 °C in ‘Penncross’. Immunoblotting also revealed stronger expressions of HSP60 and HSP70 in A. scabra or ‘L-93’ than in ‘Penncross’ at 35–45 °C after 3 d. The results suggested the superior heat tolerance of Agrostis grass species and cultivars could be attributed to the early induction of HSPs, particularly small molecular weight (23 kDa), at a lower level of heat stress and the maintenance of protein thermostability, particularly high-molecular weight proteins (83 kDa and large units of Rubisco).     

Thermolabile antifreeze protein produced in Escherichia coli for structural analysis

Inclusion bodies of recombinant human growth hormone (r-hGH) were isolated from Escherichia coli, enriched and solubilized in 100 mM Tris buffer containing 6 M n-propanol and 2 M urea. Around 4 mg/ml of r-hGH from inclusion bodies were solubilized in 6 M n-propanol-based buffer containing 2 M urea. Existence of native-like secondary structure of r-hGH in 6 M n-propanol solution was confirmed by CD and fluorescence spectra. Solubilized r-hGH was subsequently refolded by pulsatile dilution, purified to homogeneity and found to be functionally active. Tris buffer containing 6 M n-propanol and 2 M urea also effectively solubilized a number of proteins expressed as inclusion bodies in E. coli. Mild solubilization of inclusion body proteins, chaotropic effect of n-propanol at high concentration and kosmotropic effect at lower concentration helped in improved refolding of the solubilized protein. Around 40% of the r-hGH in the form of inclusion body aggregates was refolded into bioactive form while using n-propanol as solubilization agent. Solubilization with 6 M n-propanol solution thus can be a viable alternative for achieving high throughput recovery of bioactive protein from inclusion bodies of E. coli.