BmNPV Resistance of Silkworm Larvae Resulting from the Ingestion of TiO2 Nanoparticles

Bombyx mori nucleopolyhedrovirus (BmNPV) causes infection in the silkworm that is often lethal. The infection is hard to prevent, partly because of the nature of the virus particles and partly because of the different strains of B. mori. Titanium dioxide nanoparticles (TiO₂ NPs) have been demonstrated to have antimicrobial properties. The present study investigated whether TiO₂ NPs added to an artificial diet can increase the resistance of B. mori larvae to BmNPV and examined the molecular mechanism behind any resistance shown. The results indicated that ingested TiO₂ NPs decreased reactive oxygen species and NO accumulation in B. mori larvae under BmNPV infection, which in turn led to a decrease in their growth inhibition and mortality. In addition, the TiO₂ NPs significantly promoted the expression of resistance-related genes, including those encoding superoxide dismutase, catalase, glutathione peroxidase, acetylcholine esterase, carboxylesterase, heat shock protein 21, glutathione S transferase o1, P53, and transferring and of genes encoding cytochrome p302 and nitric oxide synthase. These findings are a useful addition to the understanding of the mechanism of BmNPV resistance of B. mori larvae in response to TiO₂ NPs addition. Such information also provides a theoretical basis for the use of TiO₂ NPs in sericulture.     

Effects of nanosized titanium dioxide on the photosynthetic metabolism of fenugreek (Trigonella foenum-graecum L.)

The potential toxicity of nanoparticles in plants is scarce and contradictory. Despite the diversity of research efforts, a detailed explanation of the TiO₂NPS effects in plant photosynthesis is still missing. The present work gives a new approach to examine the impact of the TiO₂NPs on crop production (development and photosynthesis) and plant protection (tolerance and defense systems) in fenugreek (Trigonella foenum graecum L.). Seedlings were assessed in greenhouse trials to estimate the influence of TiO₂NPs on physiological characters for 16 days. They were treated with TiO₂NPs at a size less than 20 nm. The results revealed that there were no significant effects on seedlings growth and biomass of stem, but a decrease in the fresh weight of leaves after TiO₂NPs treatment. Plants treated with 100 mg·L^?1 of TiO₂NPs presented a reduction and chlorosis in leaf area due to a significant decrease in the chlorophyll a and b contents. The highest value of the photosynthetic pigments was recorded at 50 mg·L^?1 of TiO₂NPs. However, the treatment with 100 mg·L^?1 of TiO₂NPs caused a decrease in the levels of chlorophyll a, b and of carotenoids. Both doses of TiO₂NPs induced an accumulation of anthocyanins compared to the control after 16 days of seedling development. A nano-stress significantly decreased the flavonoids level, but increased that of polyphenols compared to control after 16 days of exposure. The decrease in the translocation ratio of flavonoids suggests that many of them contain an enediol group, which suggests that they may act as bidentate ligands for anatase TiO₂NPs. Accordingly, nano-stressed leaves exhibited significantly enhanced GPOX, CAT and APX activity levels. On the contrary, GPOX and CAT activities were reduced substantially in stems treated with 100 mg·L^?1 TiO₂NPs. The accumulation of MDA was found to be higher in stems than in leaves. This could be explained by the accumulation of nanoparticles in different organs; it could be that the stems are the favored targets of nanoparticles. These results underline the necessity for a deeper estimation of nanoparticle ecotoxicity and particularly concerning their interaction with plants.     

Purification,modification and inhibition mechanism of angiotensin I-converting enzyme inhibitory peptide from silkworm pupa (Bombyx mori) protein hydrolysate

Angiotensin I-converting enzyme (ACE) inhibitory peptide from silkworm pupa (Bombyx mori) was purified, modified, as well as inhibition mechanism by using molecular docking analysis. Silkworm pupa protein was hydrolyzed by neutral protease and the obtained hydrolysate was subjected to various types of chromatography to acquire peptide isolate. Then the molecular mass and amino acid sequence of the peptide was determined by MALDI-TOF/TOF MS. Subsequently, thermal and digestive stability of the peptide were explored through a high temperature processing and a simulated gastrointestinal digestion. Finally, the peptide was modified to smaller peptides and investigated their potentiate activities. Results showed that the peptide from silkworm pupa was determined to be Gly-Asn-Pro-Trp-Met (603.7 Da) with IC₅₀ 21.70 μM. Stability testing showed that ACE inhibitory activities were not significantly changed at temperature from 40 to 80 °C as well as during in vitro gastrointestinal digestion. The inhibitory activity of four modified peptides were Trp-Trp > Gly-Asn-Pro-Trp-Trp > Asn-Pro-Trp-Trp > Pro-Trp-Trp, and the IC₅₀ of Trp-Trp was 10.76 μM Docking simulation revealed that the inhibitory activity was closely related to the spatial structure of peptide and zinc ions. The purified peptide and four modified peptides may be beneficial as functional food or drug for treating hypertension.     

Structural and diffusion properties of formamide/water mixture interacting with TiO2 surface

The photoreaction and adsorption properties on surfaces, thermal decomposition, chemical transformation, and other properties of the formamide molecule are widely used to understand the origins of the formation of biological molecules (nucleosides, amino acids, DNA, monolayers, etc.) needed for life. The titanium oxide (TiO₂) surface can act both as a template on which the accumulation of adsorbed molecules like formamide occurs through the concentration effect, and as a catalytic material that lowers the activation energy needed for the formation of intermediate products. In this paper, a formamide–water solution interacting with TiO₂ (anatase) surface is simulated using the molecular dynamics method. The structural, diffusion and density properties of formamide–water mixture on TiO₂ are established for a wide temperature range from T = 250 K up to T = 400 K.     

Synthesis,spectral and magnetical characterization of monomeric [Cu(2-NO2bz)2(3-pyme)2(H2O)2] and polymeric [Cu{3,5-(NO2)2bz}2(3-pyme)2]n

Two new complexes of composition [Cu(2-NO₂bz)₂(3-pyme)₂(H₂O)₂] (1) and/or [Cu{3,5-(NO₂)₂bz}₂(3-pyme)₂] (2) (3-pyme = 3-pyridylmethanol, ronicol or 3-pyridylcarbinol, 2-NO₂bz = 2-nitrobenzoate and 3,5-(NO₂)₂bz = 3,5-dinitrobenzoate) have been prepared and studied by elemental analysis, electronic, infrared and EPR spectroscopy, magnetic susceptibility measurements and the structure of both complexes has been solved. Complex (1) shows an unusual molecular type of structure consisting of the [Cu(2-NO₂bz)₂(3-pyme)₂(H₂O)₂] molecules held together by hydrogen bonds and van der Waals interactions. Complex (2) exhibits a polymeric chain-like structure [Cu{3,5-(NO₂)₂bz}₂(3-pyme)₂]_n with copper atoms doubly bridged by two 3-pyridylmethanol molecules and the polymeric molecules are held together by van der Waals interactions. Complex (1) exhibits a magnetic moment μ_eff = 1.84 B.M. at 300 K that remains nearly constant within the temperature region (5–300 K). Further cooling results in lowering the magnetic moment to μ_eff = 1.82 B.M. at 1.8 K. The magnetic susceptibility temperature dependence obeys Curie–Weiss law with Curie constant of 0.423 cm³ K mol⁻¹ and with Weiss constant of −0.06 K. The magnetic moment of (2) exhibits a small increase with a decrease in the temperature (μ_eff = 1.80 B.M. at 300 K and μ_eff = 1.85 B.M. at 1.8 K) with Curie constant of 0.409 cm³ K mol⁻¹ and with Weiss constant of +1.1 K, which can indicate a very weak ferromagnetic interaction between the copper atoms within the chain. Applying the molecular field model resulted in obtaining zJ′ values −0.08 cm⁻¹ for complex (1), and −0.07 cm⁻¹ for complex (2), respectively, that could characterize intermolecular and interchain interactions transmitted through π–π stacking.     

Synthesis and SAR of derivatives based on 2-biarylethylimidazole as bombesin receptor subtype-3 (BRS-3) agonists for the treatment of obesity

This Letter describes a series of potent and selective BRS-3 agonists containing a biarylethylimidazole pharmacophore. Extensive SAR studies were carried out with different aryl substitutions. This work led to the identification of a compound 2-{2-[4-(pyridin-2-yl)phenyl]ethyl}-5-(2,2-dimethylbutyl)-1H-imidazole 9 with excellent binding affinity (IC₅₀ = 18 nM, hBRS-3) and functional agonist activity (EC₅₀ = 47 nM, 99% activation). After oral administration, compound 9 had sufficient exposure in diet induced obese mice to demonstrate efficacy in lowering food intake and body weight via BRS-3 activation.     

Bromeliothrix metopoides,a boom and bust ciliate (Ciliophora,Colpodea) from tank bromeliads

We investigated the recently described colpodid ciliate Bromeliothrix metopoides in a series of laboratory experiments to reveal the environmental factors that constrain this species to its peculiar habitat, i.e. the tanks of bromeliads. Our results demonstrated that the various life stages of this ciliate (bacterivorous theronts and microstome trophonts, flagellate-feeding macrostomes) have specific demands in terms of food quality and quantity. Bromeliothrix required a high food threshold (>1.4 mg C L^?1) in order to thrive. Food quality also affected resting cyst formation of B. metopoides when the experimental containers dried out. Its maximum growth rates (μ_max = 4.71 d^?1, i.e. 6.8 doublings d^?1) belong to the highest ones recorded thus far for free-living ciliates. The pH niche of B. metopoides was relatively wide (pH ～4 to >9) under optimal food conditions. However, its high sensitivity to unfavourable environmental conditions let the population collapse within several hours. We conclude that B. metopoides is a boom and bust ciliate that is specifically adapted to its peculiar habitat but virtually unviable in other environments.     

Protective role against hydrogen peroxide and fibroblast stimulation via Ce-doped TiO2 nanostructured materials

BackgroundCerium oxide (CeO₂) and Ce-doped nanostructured materials (NMs) are being seen as innovative therapeutic tools due to their exceptional antioxidant effects; nevertheless their bio-applications are still in their infancy.MethodsTiO₂, Ce–TiO₂ and CeO₂–TiO₂ NMs were synthesized by a bottom-up microemulsion-mediated strategy and calcined during 7 h at 650 °C under air flux. The samples were compared to elucidate the physicochemical characteristics that determine cellular uptake, toxicity and the influence of redox balance between the Ce^3 +/Ce^4 + on the cytoprotective role against an exogenous ROS source: H₂O₂. Fibroblasts were selected as a cell model because of their participation in wound healing and fibrotic diseases.ResultsCe–TiO₂ NM obtained via sol–gel reaction chemistry of metallic organic precursors exerts a real cytoprotective effect against H₂O₂ over fibroblast proliferation, while CeO₂ pre-formed nanoparticles incorporated to TiO₂ crystalline matrix lead to a harmful CeO₂–TiO₂ material. TiO₂ was processed by the same pathways as Ce–TiO₂ and CeO₂–TiO₂ NM but did not elicit any adverse or protective influence compared to controls.ConclusionsIt was found that the Ce atoms source and its concentration have a clear effect on material's physicochemical properties and its subsequent influence in the cellular response. It can induce a range of biological reactions that vary from cytotoxic to cytoprotective.General significanceEven though there are still some unresolved issues and challenges, the unique physical and chemical properties of Ce-based NMs are fascinating and versatile resources for different biomedical applications.     

The CCKB antagonist CI988 reduces food intake in fasted rats via a dopamine mediated pathway

Studies have shown a reduction of food intake following peripheral and brain injection of CCK. However, it remains to be established whether endogenous central CCK is involved in the regulation of food intake. We investigated the role of central CCK in the regulation of food intake by pharmacological manipulation of the CCK_B (CCK₂) receptor system. Intracerebroventricularly (ICV) cannulated male Sprague Dawley rats were fasted for 24 h and received an ICV injection of the CCK_B receptor antagonist CI988 at a dose of 10 nmol or 49 nmol or vehicle. Another group received two consecutive ICV injections consisting of the corticotropin-releasing factor (CRF) receptor-1 (CRF₁) antagonist, CP376395 (3 nmol) or the CRF₂ receptor antagonist, K41498 (2 nmol) alone, or followed by CI988 (49 nmol). Lastly, another group of rats received an intraperitoneal (IP) injection of the dopamine antagonist, flupentixol (∼197 and ∼493 nmol/kg) alone, or followed by CI988 (49 nmol, ICV). Cumulative food intake was assessed for 11 h. Vehicle injected rats showed a robust feeding response. CI988 at 49 nmol reduced food intake by 30% starting at 2 h post injection. CP376395 and K41498 had no effect on food intake. Flupentixol injected IP at a dose of 197 and 493 nmol/kg alone did not modulate food intake whereas the higher dose blocked the CI988-induced reduction of feeding. During the dark phase, CI988 had no effect on food intake in unfasted rats. In summary, CCK_B signaling is involved in the regulation of food intake after a fast likely by downstream dopamine signaling.     

Bombyx mori cathepsin D expression is induced by high temperature and H2O2 exposure

Cathepsin D is involved in the metamorphosis of the silkworm, Bombyx mori. Here, we show the expression profile of B. mori cathepsin D (BmCatD) in the fat body during exposure to stressors, such as high temperature and H₂O₂. Exposure of larvae in the fifth instar stage to high temperature (28 °C) led to accelerated metamorphosis and shortened larval stage compared to control larvae grown at 23 °C. Concomitantly, the expression level of BmCatD mRNA was greatly increased during exposure to high temperature. We also detected significantly elevated H₂O₂ levels in the hemolymph of larvae treated with high temperature. To confirm that oxidative stress induces BmCatD expression, B. mori larvae were injected with H₂O₂. As predicted, we observed increased expression of BmCatD following H₂O₂ exposure. Based on these results, we conclude that BmCatD expression is induced by high temperature and H₂O₂ exposure and that this stress-induced BmCatD expression leads to early metamorphosis.     

Energy metabolism and thermoregulation in pygmy lorises (Nycticebus pygmaeus) from Yunnan Daweishan Nature Reserve

The pygmy loris (Nycticebus pygmaeus) is a small prosimian living in Vietnam, Laos, eastern Cambodia and the south part of China. In China it is only found in Pingbian, Hekou, Jinping, Luchun of Yunnan. As N. pygmaeus is seriously threatened by hunting, trade and habitat destruction, it is listed in Appendix II of CITES, and in 2006 the IUCN classified it as “vulnerable”. In order to understand the characteristics of energy metabolism and thermoregulation of N. pygmaeus, the resting metabolic rate (RMR) and body temperature (T_b) at different ambient temperature (T_a) of pygmy lorises, as well as body mass, energy intake, digestable energy intake, digestability and the thermal conductance were measured in captivity. The results obtained mainly are as follows: (1) Pygmy loris feed dry food averaged 12.90 ± 1.02 g/d. They could gain 214.87 ± 16.65 kJ/d from food intake, and earned 200.15 ± 16.36 kJ digestable energy intake per day with 90.13 ± 1.34% of the digestability. (2) The T_b at room temperatures was a little low (35.23 ± 0.16 °C) and varied with T_a from 25 °C to 35 °C. There was a positive relationship between T_b and T_a, which was described as: T_b = 27.22 + 0.34T_a (r = 0.880). (3) The resting metabolic rate (RMR) of the pygmy loris was 0.3844 ± 0.0162 mlO₂/g/h, which was 51.91 ± 1.90% of the previous predicted rate by Kleiber (1961) [21]. (4) The average thermal conductance of the pygmy loris (N. pygmaeus) was 0.0449 ± 0.0031 mlO₂/g/h/°C. These characteristics of energy metabolism and thermoregulation of N. pygmaeus in Yunnan Daweishan Nature Reserve might be considered as the adaptive characteristics to their environment in tropical semi-evergreen forests and secondary forests.     

Morphological abnormalities and lethality in silkworm (Bombyx mori) larvae treated with high concentrations of insect growth-blocking peptide

Insect growth-blocking peptides (GBPs) exhibit growth-blocking and paralytic activity. Low concentrations of GBP stimulate larval growth, whereas high concentrations of GBP significantly retard larval growth. Here, we show that morphological abnormalities and lethality were induced in silkworm (Bombyx mori) larvae by high concentrations of GBP. Active B. mori GBP (BmGBP) was produced by treating recombinant proBmGBP (expressed in baculovirus-infected insect cells) with bovine factor Xa. When silkworm larvae on day 1 of the fifth-instar stage were injected between the seventh and eight abdominal segments with BmGBP (100 or 500 ng/larva), the larval–pupal and pupal–adult transformations of these silkworms were delayed in a dose-dependent manner. However, a high concentration (2000 ng/larva) of BmGBP or Spodoptera exigua GBP (SeGBP) acutely induced morphological abnormalities and death in silkworm larvae. In silkworm larvae treated with high concentrations of GBPs, the ingested food excessively accumulated in the foregut, which caused extreme swelling in both the thorax and the foregut and resulted in larval death. Therefore, these results not only provide insight into the effect of insect GBPs on gut physiology but also reveal a novel function of insect GBPs.     

Digestive capacities allow the Mexican long-nosed bat (Leptonycteris nivalis) to live in cold environments

Digestive capabilities of nectar-feeding vertebrates to assimilate sugars affect their ability to acquire and store energy and could determine the minimal temperatures at which these animals can survive. Here, we described the sugar digestive capability of Leptonycteris nivalis and related it with its capacity to live in cold environments. We measured the enzymatic activity, food intake rate and changes in body mass of bats feeding at four different sucrose concentrations (from 5 to 35% wt./vol.). Additionally, we used a mathematical model to predict food intake and compared it with the food intake of bats. L. nivalis was able to obtain ~ 111.3 kJ of energy regardless of the sugar concentration of their food. Also, bats gained ~ 2.57 g of mass during the experimental trials and this gain was independent of sugar concentration. The affinity (1 / K_m) of sucrase (EC 3.2.1.48) was one order of magnitude higher relative to that reported for its sister species Leptonycteris yerbabuenae (0.250 and 0.0189 mmol^? 1 L, respectively), allowing this species to have a higher energy intake rate. We propose that the high ability to acquire energy conferred L. nivalis the faculty to invade cold environments, avoiding in this way the ecological competition with its sympatric species L. yerbabuenae.     

Electronic structure of [Ga2(tren)2(CAsq,cat)](BPh4)2(BF4): An EPR,ENDOR, and density functional study

The bimetallic [M₁M₂(tren)₂(CA^n?)]^m+ series, where M = Ga^III or Cr^III and CA is the chloranilate ligand which can take on diamagnetic (CA^cat,cat)^4? or paramagnetic (CA^sq,cat)^3? forms, comprises an electronically diverse series of compounds ranging from the closed-shell [Ga₂(tren)₂(CA^cat,cat)]²⁺ to the S = 5/2 ground state of [Cr₂(tren)₂(CA^sq,cat)]³⁺. This report deals with the interpretation of the EPR and ENDOR spectra of [Ga₂(tren)₂(CA^sq,cat)](BPh₄)₂(BF₄) (2) and the related derivative [Ga₂(tren)₂(DHBQ)](BPh₄)₂(BF₄) (2a) (where DHBQ is the fully deprotonated trianionic form of 2,5-dihydroxy-1,4-benzoquinone) in an effort to further characterize the electronic structure of this radical species. The X-band (～9.5 GHz) EPR spectrum of complex 2 acquired in a butyronitrile/propionitrile glass at 4 K reveals a rhombic g-tensor with g_xx = 2.0100, g_yy = 2.0097, and g_zz = 2.0060 with hyperfine interactions due to spin delocalization onto the two Ga nuclei (a_xx = 4.902 G, a_yy = 4.124 G, a_zz = 3.167 G); the origin of the hyperfine coupling was confirmed by analysis of the room temperature spectra of complexes 2 and 2a. The low-temperature spectrum of complex 2 also indicates the presence of a triplet electronic state characterized by a g-value of 2.009 and axial zero-field splitting of D = 150 G (0.012 cm^?1) as determined from measurements carried out at both X- and W-band (～95 GHz) frequencies. This triplet state is believed to arise due to a weak intermolecular Heisenberg exchange interaction between two aggregating complexes. ENDOR measurements on complex 2a at 20 K allowed for a determination of the magnitude of hyperfine coupling to the protons associated with the radical bridge as well as providing a rare example of an ENDOR signal arising from coupling to a gallium nucleus. Finally, these results were combined with literature data on the free semiquinone form of the bridging ligand in order to assess the extent to which density functional theory can predict unpaired spin density distribution in a complex molecule of this type. Although differences between theory and experiment were noted, DFT was able to provide a reasonably accurate picture of the electronic structure of this system as well as provide insight into the spin polarization mechanism(s) responsible for the observed hyperfine interactions.     

Dietary supplementation of green synthesized manganese-oxide nanoparticles and its effect on growth performance,muscle composition and digestive enzyme activities of the giant freshwater prawn Macrobrachium rosenbergii

The green synthesized Mn₃O₄ nanoparticles (manganese-oxide nanoparticles) using Ananas comosus (L.) peel extract was characterized by various techniques. HR-SEM photograph showed that manganese-oxide nanoparticles (Mn-oxide NPs) were spherical in shape, with an average size of 40–50 nm. The Zeta potential revealed the surface charge of Mn-oxide NPs to be negative. Further, the Mn-oxide NPs were dietary supplemented for freshwater prawn Macrobrachium rosenbergii. The experimental basal diets were supplemented with Mn-oxide NPs at the rates of 0 (control), 3.0, 6.0, 9.0, 12, 15 and 18 mg/kg dry feed weight. The as-supplemented Mn-oxide NPs were fed in M. rosenbergii for a period of 90 days. The experimental study demonstrated that prawns fed with diet supplemented with 3–18 mg Mn-oxide NPs/kg shows enhanced (P < 0.05) growth performance, including final weight and weight gain (WG). Significant differences (P < 0.05) in feed conversion ratio (FCR) were observed in prawn fed with different diets. Additionally, prawns fed with 3.0–18 mg/kg Mn-oxide NPs supplemented diets achieved significant (P < 0.05) improvement in growth performance, digestive enzyme activities and muscle biochemical compositions, while, the prawns fed with 16 mg/kg of Mn-oxide NPs showed enhanced performance. Prawns fed on diet supplemented with 16 mg/kg Mn-oxide NPs showed significantly (P < 0.05) higher total protein level. The antioxidants enzymatic activity (SOD and CAT) metabolic enzymes status in muscle and hepatopancreas showed no significant (P > 0.05) alterations in prawns fed with 3.0–18 mg/kg of Mn-oxide NPs supplemented diets. Consequently, the present work proposed that 16 mg/kg of Mn-oxide NPs could be supplemented for flexible enhanced survival, growth and production of M. rosenbergii. Therefore, the data of the present study recommend the addition of 16 mg/kg of Mn-oxide NPs diet to developed prawn growth and antioxidant defense system.     

Intravenous injection of urocortin 1 induces a CRF2 mediated increase in circulating ghrelin and glucose levels through distinct mechanisms in rats

Urocortins (Ucns) injected peripherally decrease food intake and gastric emptying through peripheral CRF₂ receptors in rodents. However, whether Ucns influence circulating levels of the orexigenic and prokinetic hormone, ghrelin has been little investigated. We examined plasma levels of ghrelin and blood glucose after intravenous (iv) injection of Ucn 1, the CRF receptor subtype involved and underlying mechanisms in ad libitum fed rats equipped with a chronic iv cannula. Ucn 1 (10 μg/kg, iv) induced a rapid onset and long lasting increase in ghrelin levels reaching 68% and 219% at 0.5 and 3 h post injection respectively and a 5-h hyperglycemic response. The selective CRF₂ agonist, Ucn 2 (3 μg/kg, iv) increased fasting acyl (3 h: 49%) and des-acyl ghrelin levels (3 h: 30%) compared to vehicle while the preferential CRF₁ agonist, CRF (3 μg/kg, iv) had no effect. <!-- no-mfc -->Ucn 1's<!-- /no-mfc --> stimulatory actions were blocked by the selective CRF₂ antagonist, astressin₂-B (100 μg/kg, iv). Hexamethonium (10 mg/kg, sc) prevented Ucn 1-induced rise in total ghrelin levels while not altering the hyperglycemic response. These data indicate that systemic injection of Ucns induces a CRF₂-mediated increase in circulating ghrelin levels likely via indirect actions on gastric ghrelin cells that involves a nicotinic pathway independently from the hyperglycemic response.     

Effect of TiO2 NPs on the growth,anatomic features and biochemistry parameters of Baby sun rose (Aptenia cordifolia)

Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium dioxide (TiO₂). TiO₂ NPs have photocatalytic nature and can affect plant growth. The current study investigated the morphological, anatomical and biochemical features of Baby sun rose (Aptenia cordifolia) after exposure to different concentrations of TiO₂ nanoparticles (0, 1, 5, 10 and 20 mg L⁻¹). Treatment with TiO₂ NPs showed changes in the morphological features and increased photosynthetic pigmentation within the plant. An increase in the level of phenolics (12%) and flavonoid compounds (13%) was observed when plants were treated with moderate levels of TiO₂ NPs. A reduction in the diameter of the vascular bundles and increased thickening of the transverse wall were observed in several samples. The number of scattered vascular bundles in the stems increased. The morphological, biochemical, and anatomical responses of Baby sun rose indicates that plants can adapt to environments contaminated with up to 20 mg L⁻¹ TiO₂ NPs_. The cultivation of Baby sun rose plants in environments polluted with TiO₂ NPs is recommended. This study enhances the knowledge of the effect of TiO₂ NPs on the growth of Baby sun rose which is an ornamental plant, widely cultivated in different regions of Iran. The results of this study suggest that contaminated environments up to 20 mg L⁻¹ TiO₂ NPs can be managed by phytoremediation. Further studies are needed to investigate this plant''s tolerance strategies against stress caused by TiO₂ NPs and bulk TiO₂ as well as the effect of other nanoparticles on plant.     

Molecular docking,a tool to determine interaction of CuO and TiO2 nanoparticles with human serum albumin

BackgroundWe study the human serum albumin (HSA) protein-CuO nanoparticle interaction to identify the specific binding site of protein with CuO nanoparticles by molecular docking and compared it with HSA-TiO₂ nanoparticle interaction.MethodsThe protein structural data that was obtained using Autodock 4.2.ResultsIn case of CuO np-HSA interaction, the distances from the centre of Subdomain IIIA to Arg-472 is 2.113 Å and Lys 475, Glu 492, Ala 490, Cys 487, Ala 490 are the bound neighbouring residues with Lys 475, Glu 492 at aliphatic region. The binding energy generated was ?1.64 kcal mol^?1. However, for TiO₂ nanoparticle, the binding region is surrounded by Arg 257, Ala 258, Ser 287, His 288, Leu 283, Ala 254, Tyr 150 (subdomain II A) as neighbouring residue. Moreover, Glu 285, Lys 286 forms aliphatic grove for TiO₂-HSA, Ser-287 at the centre region form hydrogen bond with nanoparticle and Leu 283, Leu 284 forming hydrophopobic grove for TiO₂ nanoparticle-HSA interaction. The binding energy generated was ?2.47 kcal mol^?1.ConclusionsAnalysis suggests that CuO bind to suldow site II i.e subdomain III A of HSA protein where as TiO₂ nanoparticle bind to suldow site I i.e subdomain IIA of HSA protein.General significanceThe structural information that derives from this study for CuO and TiO₂ nanoparticles may be useful in terms of both high and low-affinity binding sites when designing these nanoparticles based drugs delivery system.     

The complete mitogenome of Bombyx mori strain Dazao (Lepidoptera: Bombycidae) and comparison with other lepidopteran insects

The complete mitochondrial genome (mitogenome) of Bombyx mori strain Dazao (Lepidoptera: Bombycidae) was determined to be 15,653 bp, including 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and a A + T-rich region. It has the typical gene organization and order of mitogenomes from lepidopteran insects. The AT skew of this mitogenome was slightly positive and the nucleotide composition was also biased toward A + T nucleotides (81.31%). All PCGs were initiated by ATN codons, except for cytochrome c oxidase subunit 1 (cox1) gene which was initiated by CGA. The cox1 and cox2 genes had incomplete stop codons consisting of just a T. All the tRNA genes displayed a typical clover-leaf structure of mitochondrial tRNA. The A + T-rich region of the mitogenome was 495 bp in length and consisted of several features common to the lepidopteras. Phylogenetic analysis showed that the B. mori Dazao was close to Bombycidae.