Occurrence of Diadegma semiclausum,a parasitoid of diamondback moth in lowlands of Syria

The parasitoid, Diadegma semiclausum (Hymenoptera: Ichneumonidae) is one of the most effective parasitoids of diamondback moth (DBM) in the highlands (> 1600 m above sea level) of Asia. A Diadegma population from the lowland areas of Homs, Syria (about 203–487 m above sea level) was examined to determine if it differs at the species-level from the D. semiclausum and other Diadegma populations present in different countries using molecular diagnostic tools. Phylogenetic analysis based on the neighbor-joining method using the mitochondrial cytochrome oxidase I (COI) and the nuclear internal transcribed spacer 2 (ITS2) sequences grouped the Homs (Syria) Diadegma population with D. semiclausum populations from other countries. The results suggest that D. semiclausum occurs in the lowland conditions in Homs (Syria), where the temperature is higher. The Homs (Syria) strain did not show any variations in the parasitism when the parasitized host (DBM) larvae were exposed to varying temperatures for 24 h. It could not survive when the parasitized DBM larvae were continuously reared at 35 °C; however it inflicted significantly higher parasitism when the parasitized DBM larvae were reared at day and night temperatures of 35 °C and 20 °C, respectively. Preliminary results indicate that the D. semiclausum strain from Homs (Syria) possesses some level of heat tolerance, which could be exploited for successful management of DBM in the tropical lowlands.     

Morphological and morphometrical analysis of Heterodera spp. populations in Jordan

Phenotypic diversity of five Jordanian populations of cyst nematodes, Heterodera spp. collected from five regions from Jordan (Ar-Ramtha, Madaba, Dana, Al-Karak, and Jerash) was investigated. Soil samples were collected from one representative field in each region. Morphological and morphometrical characteristics revealed that Heterodera latipons is dominated in cereal fields at Ar-Ramtha, Madaba, Dana and Al-Karak regions and Heterodera schachtii in Jerash. Cysts populations from all cereal fields had bifenestrate vulval cone and a strong underbridge. Wherever, cysts of the cabbage population had ambifenestrate vulval cone with long vulval slit. The bullae were absent in Ar-Ramtha, Madaba and Dana populations, but present in Al-Karak and Jerash. Based on 12 morphometrical characters, the first three functions in canonical discriminant analysis accounted 99.3% of the total variation. Distance from dorsal gland duct opening to stylet base, underbridge length, a = L/W (body length/midbody width) and length of hyaline tail tip had strong and significant contributions in the first function. While the second function was strongly influenced by length of hyaline tail, fenestral length, fenestral width and tail length. However, the third canonical discriminate function was found to be influenced by stylet length, fenestral length, a = L/W (body length/midbody width) and underbridge width. The graphical representation of the distribution of the samples showed that the first canonical discriminant function clearly separated H. schachtii from Jerash from other populations. Whereas, H. latipons collected from Madaba and Dana were clearly separated in the second function. The results indicated that differences at morphological and morphometrical levels revealed diverse populations of Heterodera spp. in Jordan.     

Syntheses,structures, and magnetic properties of heterobimetallic complexes based on tetracyanometallic building blocks

Two tetracyanometalate building blocks, [Fe(5,5′-dmbipy)(CN)₄]^? (2) and [Fe(4,4′-dmbipy)(CN)₄]^? (3) (5,5′-dmbipy = 5,5′-dimethyl-2,2′-bipyridine; 4,4′-dmbipy = 4,4′-dimethyl-2,2′-bipyridine), and two cyano-bridged heterobimetallic complexes, [Cu₂(bpca)₂(H₂O)₂Fe₂(5,5′-dmbipy)₂(CN)₈] · 2[Cu(bpca)Fe(5,5′-dmbipy)(CN)₄] · 4H₂O (4) and [Cu(bpca)Fe(4,4′-dmbipy)(CN)₄]_n (5) (bpca = bis(2-pyridylcarbonyl)amidate), have been synthesized and structurally characterized. Complex 4 contains two dinuclear and one tetranuclear heterobimetallic clusters in an asymmetric unit whereas the structure of complex 5 features a one-dimensional heterobimetallic zigzag chain. The Cu(II) ion is penta-coordinated in the form of a distorted square-based pyramid. Magnetic studies show ferromagnetic coupling between Cu(II) and Fe(III) ions with g = 2.28, J₁ = 2.64 cm^?1, J₂ = 5.40 cm^?1 and TIP = ?2.36 × 10^?3 for complex 4, and g = 2.17, J = 4.82 cm^?1 and zJ′ = 0.029 cm^?1 for complex 5.     

Rectangular two-dimensional antiferromagnetic systems: Analysis of copper(II) pyrazine dibromide and dichloride

The structure of copper pyrazine dibromide (or dichloride) consists of dihalide-bridged copper chains parallel to the c-axis with the copper sites linked in a perpendicular direction by bridging pyrazine molecules parallel to the b-axis. Superexchange interactions are propagated through both halides and pyrazine so the magnetic structure is a rectangular layer with two exchange strengths, J and J′ (J′ = αJ), where 0 < α < 1. The susceptibility of a rectangular antiferromagnetic Heisenberg lattice with S = 1/2 has been simulated using Quantum Monte Carlo techniques and the results compared to the experimental data. Best fits of the magnetic susceptibility data to the simulated data yield: for Cu(pz)Br₂, α = 0.20(5), C = 0.430(1) emu K/mol, 2J = ?46(1) K, and 2J′ = ?9(2) K and for Cu(pz)Cl₂, α = 0.30(5), C = 0.426(1) emu K/mol, 2J = ?28(1) K, and 2J′ = ?8(2)) K. The values are in good agreement with the literature and thus demonstrate the effectiveness of the technique for rectangular lattices.     

Evaluation of the association of mercury(II) with some dicysteinyl tripeptides

The present study was undertaken to gain insight into the associations of mercury(II) with dicysteinyl tripeptides in buffered media at pH 7.4. We investigated the effects of increasing the distance between cysteinyl residues on mercury(II) associations and complex formations. The peptide–mercury(II) formation constants and their associated thermodynamic parameters in 3-(N-morpholino)propanesulfonic acid (MOPS) buffered solutions were evaluated by isothermal titration calorimetry. Complexes formed in different relative ratios of mercury(II) to cysteinyl peptides in ammonium formate buffered solutions were characterized by LTQ Orbitrap mass spectrometry. The results from these studies show that n-alkyl dicysteinyl peptides (CP 1–4), and an aryl dicysteinyl peptide (CP 5) can serve as effective “double anchors” to accommodate the coordination sites of mercury(II) to form predominantly one-to-one Hg(peptide) complexes. The aryl dicysteinyl peptide (CP 5) also forms the two-to-two Hg₂(peptide)₂ complex. In the presence of excess peptide, Hg(peptide)₂ complexes are also detected. Notably, increasing the distance between the ligating groups or “anchor points” in CP 1–5 does not significantly affect their affinity for mercury(II). However, the enthalpy change (ΔH) values (ΔH₁ ∼ −91 kJ mol⁻¹ and ΔH₂ ∼ −66 kJ mol⁻¹) for complex formation between CP 4 and 5 with mercury(II) are about one and a half times larger than the related values for CP 1, 2 and 3 (ΔH₁ ∼ −66 kJ mol⁻¹ and ΔH₂ ∼ 46 kJ mol⁻¹). The corresponding entropy change (ΔS) values (ΔS₁ ∼ −129 J K⁻¹ mol⁻¹ and ΔS₂ ∼ −116 J K⁻¹ mol⁻¹) of the structurally larger dicysteinyl peptides CP 4 and 5 are less entropically favorable than for CP 1, 2 and 3 (ΔS₁ ∼ −48 J K⁻¹ mol⁻¹ and ΔS₂ ∼ −44 J K⁻¹ mol⁻¹). Generally, these associations result in a decrease in entropy, indicating that these peptide–mercury complexes potentially form highly ordered structures. The results from this study show that dicysteinyl tripeptides are effective in binding mercury(II) and they are promising motifs for the design of multi-cysteinyl peptides for binding more than one mercury(II) ion per peptide.     

Genetic diversity and population structure in Vallisneria spinulosa (Hydrocharitaceae)

Vallisneria spinulosa is a dominant submerged macrophyte in lakes of the middle–lower reaches of the Yangtze River. Allozyme variation, clonal diversity and population genetic structure were investigated for a total of 396 individuals sampled from 10 extant populations. V. spinulosa maintained high levels of genetic variation both at the species (P = 46.2, A = 1.69, H_e = 0.23) and at the population level (P = 46.2, A = 1.58, H_e = 0.21). Although aquatic macrophytes commonly exhibit low genetic variation within populations, the obligately outcrossing mating system of V. spinulosa and pervasive gene flow likely account for the high levels of diversity maintained within populations. All V. spinulosa populations contained high clonal diversity with a mean proportion of distinguishable genotypes of 0.57 and a mean Simpson's diversity index of 0.95, indicating that populations were founded sexually or that successful seedling recruitment occurred after initial colonization. Partitioning of genetic diversity revealed a surprisingly low population differentiation (G_ST = 0.06) as compared to other hydrophilous angiosperms. No evidence of isolation-by-distance was found (r = 0.056, P = 0.312), suggesting that gene flow was not restricted geographically. The UPGMA cluster analysis revealed that several widely separated populations grouped together, suggesting long-distance gene flow among populations. The high vagility of V. spinulosa and extensive hydrologic connectivity among populations have facilitated long-distance gene flow and resulted in the pattern of population genetic structure in V. spinulosa.     

Genetic variation and clonal diversity in populations of Nelumbo nucifera (Nelumbonaceae) in central China detected by ISSR markers

To obtain accurate estimates of population structure for purposes of conservation planning for wild lotus (Nelumbo nucifera Gaertn.) in central China, genetic diversity among and within six populations, and clonal diversity within another two populations of the species were analyzed. The genetic diversity was high (percentage of polymorphic bands, PPB = 90.0%; Shannon's information index, I = 0.383 ± 0.234) at the species level, but low within individual study populations (PPB = 35.8%; Shannon's information index I = 0.165 ± 0.241). The mean coefficient of gene differentiation (G_st) was 0.570, indicating that 43.0% of the genetic diversity resided within the population. Analysis of molecular variance (AMOVA) indicated that 50.47% of the genetic diversity among the study populations was attributed to geographical location while 12.3% was attributed to differences in their habitats. An overall value of mean estimated number of gene flow (N_m = 0.377) indicated that there was limited gene flow among the sampled populations. The level of clonal diversity found within the populations was considerably high (Simpson's diversity index, D = 0.985) indicating that clonal diversity contributes to a major extent to the overall genetic variation in the genetic structure of N. nucifera. On the basis of the high G_st and D values detected in this study we recommend that any future conservation plans for this species should be specifically designed to include those representative populations with the highest genetic variation for both in situ conservation and germplasm collection expeditions.     

Magnetic properties of six-coordinated high-spin cobalt(II) complexes: Theoretical background and its application

In this contribution we study and analyse the influence of the different parameters involved in the magnetic susceptibility of six-coordinated high-spin Co(II) complexes. We propose an empirical expression to fit the magnetic susceptibility of polycrystalline samples of mononuclear Co(II) complexes with an axial distortion, the variable parameters being Δ (axial distortion), α (orbital reduction factor) and λ (spin–orbit coupling). This expression avoids solving the 12 × 12 matrix associated to the distortion of the ⁴T_1g term. In order to take into account the magnetic coupling (J) in the polynuclear Co(II) complexes, a perturbational approach is proposed to describe their magnetic susceptibility in the whole temperature range (2–300 K) as a function of J, Δ, α and λ. This approach is valid in the limit of the weak magnetic coupling as compared to the spin–orbit coupling, |J/λ| < 0.1. The model allows the treatment of each cobalt(II) ion in axial symmetry as an effective spin S_eff = 1/2. That causes a drastic reduction of the matrix size of the polynuclear compounds from 12ⁿ × 12ⁿ to 2ⁿ × 2ⁿ, n being the number of Co(II) ions in the complex. The main advantage of the model is to make possible the fit of the magnetic susceptibility data of those polynuclear Co(II) complexes whose high nuclearity involved intractable matrices.     

Anti-angiogenic activity of julibroside J8, a natural product isolated from Albizia julibrissin

PurposeThe purpose of this study was to investigate the anti-angiogenic properties of julibroside J₈, a triterpenoid saponin isolated from Albizia julibrissin.MethodsIn the presence of juliborside J_8, the growth of human microvascular endothelial cells (HMEC-1), four human tumor cell lines, and a normal cell line (MRC-5) was evaluated by MTT assay. The in vivo anti-angiogenic effect of julibroside J₈ was evaluated on a chorioallantoic membrane (CAM) and in transplanted colon carcinoma cells in a nude mice neovascularisation model.ResultsTreatment with 0.5–4 μg/ml julibroside J₈ resulted in dose-dependent inhibition of growth, migration, and tube formation in HMEC-1 cells; julibroside J₈ also inhibited the formation of microvessels on CAM at a concentration of 10–50 μg/egg and reduced vessel density within tumor at a concentration of 0.5–3 mg/kg.ConclusionsJulibroside J₈ may be a potent anti-angiogenetic and cytotoxic drug; further investigation is warranted.     

Synthesis,structures and magnetic properties of pentanuclear and trinuclear heterometallic complexes with bended and linear cyano-bridges (tren = tris(2-aminoethyl)amine)

The reaction of [Cu(tren)(OH₂)](ClO₄)₂ with KCN gave a mononuclear complex [Cu(tren)(CN)](ClO₄) (1) (tren = tris(2-aminoethyl)amine). Using 1 as a building block, one pentanuclear compound, [{Cu(tren)(NC)}₄Ni](ClO₄)₆ (2) and two trinuclear complexes, [{Cu(tren)NC}₂Co(tren)](ClO₄)₅ · 2H₂O (3), [{Cu(tren)CN}₂NiL](ClO₄)₄ (4) (L = 3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane) were prepared and characterized by single crystal X-ray analysis. In 1, Cu(II) atom adopts a distorted trigonal bipyramidal (TBP) geometry. In 2, the Ni(II) atom occupies the center of the pentanuclear compound with a square-planar coordination geometry. In 3, the six-coordinated Co(III) atom presents a distorted octahedral geometry with four nitrogen atoms from tren and two carbon atoms of bridged cyano groups in cis-positions. In 4, the nickel atom is located in an inversion center and coordinated with two [(tren)CuCN]⁺ moieties through cyano-bridging ligands. Magnetic susceptibility measurements of 2–4 show that the magnetic interactions between the heterometallic ions are antiferromagnetical coupling through the cyano bridges with g = 2.25, J = −0.142 cm⁻¹ and J′ = −0.167 cm⁻¹ for 2, g = 2.06, J = −0.094 cm⁻¹ for 3, and g = 2.20, J = −33.133 cm⁻¹ for 4. The correlations between the structures and the J values are discussed.     

Crystal structure,magnetic and thermal properties of the one-dimensional complex [Nd(pzam)3(H2O)Mo(CN)8] · H2O

The new d–f cyanido-bridged 1D assembly [Nd(pzam)₃(H₂O)Mo(CN)₈] · H₂O was prepared by self-assembly of pyrazine-2-carboxamide (pzam), Nd(NO₃) · nH₂O and (Bu₃NH)₃[Mo(CN)₈] · 4H₂O in acetonitrile. X-ray crystallographic studies indicate that the complex comprises chains of alternating, cyanido-bridged [Nd(pzam)₃(H₂O)]³⁺ and Mo(CN)₈]^3? fragments. The magneto-structural properties have been studied by field-dependent magnetization and specific heat measurements at low temperatures (?0.3 K). Below ≈10 K the Nd(III) moment is well approximated by an effective spin S = 1/2, with anisotropic g-tensor. The exchange coupling between the Nd(III) and the Mo(V) spins S = 1/2 along the structural chains is found to be ferromagnetic, with J/k_B = 1.8 ± 0.2 K and approximately XY (planar) anisotropy. No evidence for 3D interchain magnetic ordering is found. A comparison with magneto-structural data of other cyanido-bridged complexes involving the Nd(III) ion is presented.     

High allozymic diversity in natural populations of Mycoheterotrophic Orchid Gastrodia elata,an endangered medicinal plant in China

Gastrodia elata Blume, a mycoheterotrophic orchid native to the Far East, is an endangered medicinal plant in China. Genetic variation among 19 natural populations of G. elata was examined in central China by using allozyme polymorphism (16 loci in six enzymatic systems). The species exhibited high level of genetic diversity (P = 56.3%, A = 2.2 and H_E = 0.221), which was mainly attributed to its perennial habit and mixed reproduction system (both sexual and asexual). Evident genetic differentiation in G. elata natural populations was suggested by F_ST = 0.241. AMOVA analysis showed 31.3% of the total molecular variation was attributed to inter-population differentiation. Obvious genetic structure and genetic depauperation of some populations indicate forest fragmentation and over-collection have affected genetic variation of G. elata. A conservation strategy, which is conserving populations with great genetic distinction or high level of genetic variation from four management units, is recommended.     

Alexandrium pacificum Litaker sp. nov (Group IV): Resting cyst distribution and toxin profile of vegetative cells in Bizerte Lagoon (Tunisia,Southern Mediterranean Sea)

A high spatial resolution sampling of Alexandrium pacificum cysts, along with sediment characteristics (% H₂O, % organic matter (OM), granulometry), vegetative cell abundance and environmental factors were investigated at 123 study stations in Bizerte Lagoon (Tunisia). Morphological examination and ribotyping of cells obtained from a culture called ABZ1 obtained from a cyst isolated in lagoon sediment confirmed that the species was A. pacificum. The toxin profile from the ABZ1 culture harvested during exponential growth phase was simple and composed of the N-sulfocarbamoyl toxins C1 (9.82 pg toxin cell⁻¹), the GTX6 (3.26 pg toxin cell⁻¹) and the carbamoyl toxin Neo-STX (0.38 pg toxin cell⁻¹). The latter represented only 2.8% of the total toxins in this strain.High abundance of A. pacificum cysts correlated with enhanced percentages of water and organic matter in the sediment. In addition, sediment fractions of less than 63 μm were examined as a favorable potential seedbed for initiation of future blooms and outbreaks of A. pacificum in the lagoon. A significant difference in the cyst distribution pattern was recorded among the lagoon's different zones, with the higher cyst abundance occurring in the inner waters. Also, no correlation due to the specific hydrodynamics of the lagoon was observed in the spatial distribution of A. pacificum cysts and vegetative cells.     

Extended rhodamine photosensitizers for photodynamic therapy of cancer cells

Extended thio- and selenorhodamines with a linear or angular fused benzo group were prepared. The absorption maxima for these compounds fell between 640 and 700 nm. The extended rhodamines were evaluated for their potential as photosensitizers for photodynamic therapy in Colo-26 cells. These compounds were examined for their photophysical properties (absorption, fluorescence, and ability to generate singlet oxygen), for their dark and phototoxicity toward Colo-26 cells, and for their co-localization with mitochondrial-specific agents in Colo-26 and HUT-78 cells. The angular extended rhodamines were effective photosensitizers toward Colo-26 cells with 1.0 J cm⁻² laser light delivered at λ_max ± 2 nm with values of EC₅₀ of (2.8 ± 0.4) × 10⁻⁷ M for sulfur-containing analogue 6-S and (6.4 ± 0.4) × 10⁻⁸ M for selenium-containing analogue 6-Se. The linear extended rhodamines were effective photosensitizers toward Colo-26 cells with 5 and 10 J cm⁻² of broad-band light (EC₅₀’s ⩽ 2.4 × 10⁻⁷ M).     

Synthesis,structures and characterization of the dinuclear nickel(II) complexes containing N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane and an azide ion

Two dinuclear nickel(II) complexes, [Ni₂(L-Et)(N₃)(H₂O)₃](NO₃)₂ · 2H₂O (1) and [Ni₂(L-Et)(μ-1,3-N₃)(H₂O)₂](NO₃)₂ · 4H₂O (2) containing (HL-Et = N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane), have been synthesized and characterized by their IR and UV–Vis spectra and magnetic susceptibilities. The crystal structures of [Ni₂(L-Et)(N₃)(H₂O)₃](NO₃)₂ · CH₃OH (1′) and [Ni₂(L-Et)(μ-1,3-N₃)(H₂O)₂](NO₃)₂ · 2C₂H₅OH (2′) similar to 1 and 2 were determined by X-ray crystallography. In 1′, the two nickel(II) ions are bridged by only an alkoxo group of L-Et⁻, while an azido and an alkoxo connect two nickel(II) ions in 2′. Magnetic susceptibility measurements (2–300 K) showed a weak ferromagnetic exchange coupling between the two nickel(II) ions (2J = 10.1 cm⁻¹) for 1. On the other hand, antiferromagnetic interactions were observed for 2 (2J = −15.8 cm⁻¹).     

Characterization of genetic variance within and among five populations of Sperata seenghala (Skyes, 1839) revealed by random amplified polymorphic DNA markers

The genetic diversity among five populations (Bhadbada reservoir, Mohinisagar reservoir, Bansagar reservoir, Bargi reservoir and Gandhisagar reservoir) was revealed using random amplified polymorphic DNA markers. 10 random primers screened, 5 primers revealed various banding patterns and yielded 71 total loci as an average of which 39.60 (55.77%) were polymorphic between the population and 86.84% within the population of Sperata seenghala. Population wise the highest genetic polymorphism was obtained in Bhadbada reservoir as 67.61% whereas the lowest was in Gandhisagar reservoir as 49.30%. However, Analysis of Molecular Variance indicated low genetic diversity (H_pop = 0.0921 ± 0.1249; I = 0.1584 ± 0.1942) in Bansagar reservoir. Relative genetic differentiation (G_ST = 0.3993) and restricted gene flow (N_m = 0.7523) as an average indicated low gene diversity among the fish populations. The un-weighted pair group method with averages (UPGMA) dendrogram showed 05 major clusters, each cluster representing a population. Fish population of Mohinisagar reservoir showed high genetic distance (0.3981) with respective Bargi reservoir population and highest genetic identity (0.8846) reflected between Bansagar and Gandhisagar reservoir. Highest genetic distance between Mohinisagar and Bargi reservoir fish populations shows no significant correlation between genetic and geographical distance of the genotypes collected from different lentic and geographical isolated water bodies. This investigation indicated that lowest genetic diversity existed in different geographic populations of S. seenghala. All the five populations were found to be low in genetic variation, which is useful information for future conservation measures of S. seenghala confined in natural water bodies of Madhya Pradesh.     

Monitoring of acaricide resistance of Tetranychus urticae (Acari: Tetranychidae) from Korean apple orchards

Tetranychus urticae populations were collected from ten commercial apple orchards and their susceptibilities to 12 acaricides were tested using a leaf disc bioassay. The resistance of each T. urticae population was reported as the LC₅₀ value, the resistance ratio (RR) and the slope of the probit–concentration regression. Cross resistances of T. urticae populations were estimated using the Spearman's rank correlation coefficient. Most local populations showed low resistance levels (RR ≤ 10). Development of resistance to METI and pyrethroid acaricides differed among local populations. The highest RR value (154.6) was found in the Uiseong population to tebufenpyrad. The Geochang population was highly resistant, especially to METI and pyrethroid acaricides. T. urticae populations collected from Suwon, Chungju, Yeongju and Geochang showed moderate resistance (10 < RR ≤ 40) to more than two acaricides. Resistance ratios to abamectin, chlorfenapyr, fenbutatin-oxide and milbemectin were low (RR ≤ 10) in all populations. The LC₅₀ values of abamectin, chlorfenapyr, fenbutatin-oxide and milbemectin ranged from 0.06 to 0.2 mg/l, from 0.67 to 3.38 mg/l, from 10.12 to 40.85 mg/l and from 0.47 to 3.01 mg/l, respectively. We discuss possible cross-resistance to acaricides using Spearman's rank correlation coefficient.     

Synthesis of (benzimidazol-2-yl)aniline derivatives as glycogen phosphorylase inhibitors

A series of (benzimidazol-2-yl)-aniline (1) derivatives has been synthesized and evaluated as glycogen phosphorylase (GP) inhibitors. Kinetics studies revealed that compounds displaying a lateral heterocyclic residue with several heteroatoms (series 3 and 5) exhibited modest inhibitory properties with IC₅₀ values in the 400–600 μM range. Arylsulfonyl derivatives 7 (Ar: phenyl) and 9 (Ar: o-nitrophenyl) of 1 exhibited the highest activity (series 2) among the studied compounds (IC₅₀ 324 μM and 357 μM, respectively) with stronger effect than the p-tolyl analogue 8.     

Structural characterization of thermostable,solvent tolerant,cytosafe tannase from Bacillus subtilis PAB2

Tannase production by Bacillus subtilis PAB2, was investigated under solid state fermentation using tamarind seed as sole carbon source and it was found as the highest titer (73.44 U/gds). The enzyme was purified to homogeneity, which showed the molecular mass around 52 kDa (K_m = 0.445 mM, V_max = 125.8 mM/mg/min and K_cat = 2.88 min^–1). The enzyme was found stable in a range of pH (3.0–8.0) and temperature (30–70 °C) with an optimal activity at pH 5.0, pI of 4.4 and at 40 °C temperature. It exhibited half-life (t_1/2) of 4.5 h at 60 °C. The enzyme comprised a typical secondary structure containing α-helix (9.3%), β-pleated sheet (33.6%) and β-turn (17.2%). The native conformation of the enzyme was alike a 44 nm spherical nanoparticle upon aggregation. Thermodynamic parameters of tannase revealed that it was stable at 40 °C and showed Q₁₀, ΔG_d and ΔS_d values of 2.08, 99.37 KJ/mol and 252.38 J mol⁻¹ K⁻¹, respectively. Organic solvents were stimulatory with regard to enzyme activity. Moreover, the altered enzyme activity was determined to be correlated with the changes in structural conformation in presence of inducer and inhibitor. Tannase was explored to have no cytotoxicity on Vero cell line as well as rat model study.     

Population genetics and conservation of the Azorean tree Picconia azorica

Picconia azorica (Tutin) Knobl. (Oleaceae) is an endangered species, endemic to the Azores. Samples from 31 populations in 8 islands were genotyped using 8 newly developed nuclear microsatellite markers. From the amplified loci, 81% were polymorphic across all populations and the species showed a relatively high total genetic diversity (H_T = 0.7). Several populations were close to Hardy–Weinberg equilibrium while others presented positive F_IS values (0.02–0.2). The largest proportion of genetic variation (98%) occurred within populations and the level of differentiation between populations, was generally low, although 27% of the population pairwise comparisons showed relatively high differentiation values (0.25 ≤ R_ST ≤ 0.65). Relatively high levels of gene flow were also found among most populations. Using the Bayesian clustering method implemented in STRUCTURE we found a particular genetic pattern in Corvo samples, and also similarities between Santa Maria, São Miguel and Flores populations. Considerable levels of genetic admixture within P. azorica populations might have resulted from: (i) fruit dispersal by native birds; and/or (ii) human mediated dispersal between islands. Our results revealed the existence of some genetically depauperate populations needing specific conservation measures, and indicate that arbitrary translocation of individuals between islands should be avoided.