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.     

Trispyrazolylmethane piano stool complexes of iron(II) and cobalt(II)

A series of cationic trispyrazolylmethane complexes of the general form [Tm^RM(CH₃CN)₃]²⁺ (Tm = tris(pyrazolyl)methane, 1, R = 3,5-Me₂, M = Fe(II); 2, R = 3-Ph, M = Fe(II); 3, R = 3,5-Me₂, M = Co(II); 4, R = 3-Ph, M = Co(II)) with ‘piano-stool’ structures was prepared by the reaction of the N₃tripodal ligands (Tm^R)with [(CH₃CN)₆M](BF₄)₂ in a 1:1 stoichiometric ratio. Magnetic susceptibility measurements indicate that all four complexes with BF₄⁻ counter anions are paramagnetic, high-spin systems in the solid state with μ_eff at high temperatures of 5.2 (1, S = 2), 5.4 (2, S = 2), 4.9 (3, S = 3/2) and 4.6 (4, S = 3/2) BM, respectively. Comparisons of bond lengths from the metal centre to the Tm^R nitrogen donors, and from the metal centre to the acetonitrile nitrogen donors indicate that the neutral tripodal ligands appear to be more weakly coordinated to the metal centre than are the acetonitrile ligands. Reactions of these tripodal complexes with bidentate phosphine ligands, such as 1,2-diphosphinoethane or 1,2-bis(diallylphosphino)ethane leads to displacement of the tripodal ligand, or to the formation of more thermally stable bis-ligand complexes M(Tm^R)₂ (R = 3,5-dimethyl).     

Rhizobium indicum sp. nov., isolated from root nodules of pea (Pisum sativum) cultivated in the Indian trans-Himalayas

Three strains of rhizobia isolated from effective root nodules of pea (Pisum sativum L.) collected from the Indian trans-Himalayas were characterized using 16S rRNA, atpD and recA genes. Phylogeny of the 16S rRNA genes revealed that the newly isolated strains were members of the genus Rhizobium with ≥99.9% sequence similarity to the members within the “Rhizobium leguminosarum” group. Phylogenetic analyses based on the concatenated sequences of atpD and recA gene, and 92 core genes extracted from the genome sequences indicated that strains JKLM 12A2^T and JKLM 13E are grouped as a separate clade closely related to R. laguerreae FB206^T. In contrast, the strain JKLM 19E was placed with “R. hidalgonense” FH14^T. Whole-genome average nucleotide identity (ANI) values were 97.6% within strains JKLM 12A2^T and JKLM 13E, and less than 94% with closely related species. The digital DNA-DNA hybridization (dDDH) values were 81.45 within the two strains and less than 54.8% to closely related species. The major cellular fatty acids were C_18:1w7c in summed feature 8, C_{14:0 3OH}/C_{16:1 iso I} in summed feature 2, and C_18:0. The DNA G + C content of JKLM 12A2^T and JKLM 13E was 60.8 mol%. The data on genomic, chemotaxonomic, and phenotypic characteristics indicates that the strains JKLM 12A2^T and JKLM 13E represent a novel species, Rhizobium indicum sp. nov. The type strain is JKLM 12A2^T (= MCC 3961^T = KACC 21380^T = JCM 33658^T). However, the strain JKLM 19E represents a member of “R. hidalgonense” and the symbiovar viciae.     

Evaluation of (Z)-2-((1-benzyl-1H-indol-3-yl)methylene)-quinuclidin-3-one analogues as novel,high affinity ligands for CB1 and CB2 cannabinoid receptors

A small library of N-benzyl indolequinuclidinone (IQD) analogs has been identified as a novel class of cannabinoid ligands. The affinity and selectivity of these IQDs for the two established cannabinoid receptor subtypes, CB1 and CB2, was evaluated. Compounds 8 (R = R² = H, R¹ = F) and 13 (R = COOCH₃, R¹ = R² = H) exhibited high affinity for CB2 receptors with K_i values of 1.33 and 2.50 nM, respectively, and had lower affinities for the CB1 receptor (K_i values of 9.23 and 85.7 nM, respectively). Compound 13 had the highest selectivity of all the compounds examined, and represents a potent cannabinoid ligand with 34-times greater selectivity for CB2R over CB1R. These findings are significant for future drug development, given recent reports demonstrating beneficial use of cannabinoid ligands in a wide variety of human disease states including drug abuse, depression, schizophrenia, inflammation, chronic pain, obesity, osteoporosis and cancer.     

Metabolic engineering of Saccharomyces cerevisiae for the biotechnological production of succinic acid

The production of bio-based succinic acid is receiving great attention, and several predominantly prokaryotic organisms have been evaluated for this purpose. In this study we report on the suitability of the highly acid- and osmotolerant yeast Saccharomyces cerevisiae as a succinic acid production host. We implemented a metabolic engineering strategy for the oxidative production of succinic acid in yeast by deletion of the genes SDH1, SDH2, IDH1 and IDP1. The engineered strains harbor a TCA cycle that is completely interrupted after the intermediates isocitrate and succinate. The strains show no serious growth constraints on glucose. In glucose-grown shake flask cultures, the quadruple deletion strain Δsdh1Δsdh2Δidh1Δidp1 produces succinic acid at a titer of 3.62 g L^?1 (factor 4.8 compared to wild-type) at a yield of 0.11 mol (mol glucose)^?1. Succinic acid is not accumulated intracellularly. This makes the yeast S. cerevisiae a suitable and promising candidate for the biotechnological production of succinic acid on an industrial scale.     

Energy landscape of the intact and destabilized FMO antennas from C. tepidum and the L122Q mutant: Low temperature spectroscopy and modeling study

We discuss the excitonic energy landscape of the typically studied wild-type (WT) Fenna-Matthews-Olson (FMO) antenna protein from the green sulfur bacterium Chlorobaculum tepidum (referred to as WT_M), which is described as a mixture of intact (WT_I) and destabilized (WT_D) complexes. Optical spectra of WT_M and the L122Q mutant (where leucine 122 near BChl 8 is replaced with glutamine) are compared to WT_I FMO. We show that WT_M and L122Q samples are mixtures of two subpopulations of proteins, most likely induced by protein conformational changes during the isolation/purification procedures. Absorption, emission, and HB spectra of WT_M and L122Q mutant are very similar, in which the low-energy trap (revealed by the nonresonant HB spectra) shifts to higher energies as a function of fluence, supporting a mixture model. No fluence-dependent shift is observed in the WT_I FMO trimers. New Hamiltonians are provided for WT_I and WT_D proteins. Resonant HB spectra show that the internal energy relaxation times in the WT_M and L122Q mutant are similar, and depend on excitation frequency. Fast average relaxation times (excited state lifetimes) are observed for burning into the main broad absorption band near 805 nm. Burning at longer wavelengths reveals slower total dephasing times. No resonant bleach is observed at λ_B ≤ 803 nm, implying much faster (femtosecond) energy relaxation in this spectral range in agreement with 2D electronic spectroscopy frequency maps.     

Haematopoietic TLR4 deletion attenuates perivascular brown adipose tissue inflammation in atherosclerotic mice

AimsTo investigate whether haematopoietic TLR4 deletion attenuates perivascular brown adipose tissue inflammation in atherosclerotic mice.Methods and ResultsExperiments were performed using irradiated LDL receptor-deficient (LDLR^−/−) mice with marrow from either TLR4-deficient (TLR4^−/−) or age-matched wild-type (WT) mice. After 12 weeks of being fed a high-cholesterol diet, TLR4^−/− → LDLR^−/− mice developed fewer atherosclerotic lesions in the aorta compared to WT → LDLR^−/− mice. This effect was associated with an increase in multilocular lipid droplets and mitochondria in perivascular adipose tissue (PVAT). Immunofluorescence analysis confirmed that there was an increase in capillary density and M2 macrophage infiltration, accompanied by a decrease in tumour necrosis factor (TNF)-α expression in the localized PVAT of TLR4^−/− → LDLR^−/− mice. In vitro studies indicated that bone marrow-derived macrophages (BMDMs) from WT mice demonstrated an M1-like phenotype and expression of inflammatory cytokines induced by palmitate. These effects were attenuated in BMDMs isolated from TLR4^−/− mice. Furthermore, brown adipocytes incubated with conditioned medium (CM) derived from palmitate-treated BMDMs, exhibited larger and more unilocular lipid droplets, and reduced expression of brown adipocyte-specific markers and perilipin-1 compared to those observed in brown adipocytes exposed to CM from palmitate-treated BMDMs of TLR4^−/− mice. This decreased potency was primarily due to TNF-α, as demonstrated by the capacity of the TNF-α neutralizing antibody to reverse these effects.ConclusionsThese results suggest that haematopoietic-specific deletion of TLR4 promotes PVAT homeostasis, which is involved in reducing macrophage-induced TNF-α secretion and increasing mitochondrial biogenesis in brown adipocytes.     

Methyl-palladium(II) complexes of pyridine-bridged bis(nucleophilic heterocyclic carbene) ligands: Substituent effects on structure,stability, and catalytic performance

A series of discrete, mononuclear palladium(II)–methyl complexes, together with several palladium(II)–chloro analogues, of pyridine-functionalised bis-NHC ligands have been prepared via ligand transmetallation from the silver(I)-NHC complexes. The reported complexes comprise examples with both the methylene-bridged 2,6-bis[(3-R-imidazolin-2-yliden-1-yl)methyl]pyridine (_RC^∧N^∧C; R = Mes, dipp, ^tBu) and planar 2,6-bis(3-R-imidazolin-2-yliden-1-yl)pyridine (_RCNC; R = Mes, dipp) ligands and, when combined with the previously reported _MeC^∧N^∧C/_MeCNC examples, cover a broad spectrum of ligand substituent steric and electronic properties, including the bulky Mes and dipp groups frequently used in catalytic applications. The palladium(II) complexes have been characterised by a variety of methods, including single crystal X-ray crystallography, with the shielding of the Pd–Me groups in the proton NMR spectra of some of the N-aryl substituted examples correlated with the proximity of the aryl rings to the methyl group in the solid state structures. The [PdMe(_RC^∧N^∧C/_RCNC)]⁺ complexes undergo thermal degradation via reductive methyl-NHC coupling to give 2-methyl-3-R-imidazolium-1-yl species with relative stabilities in the order of [PdMe(_MesC^∧N^∧C)]BF₄ > [PdMe(_MeC^∧N^∧C)]BF₄ ≈ [PdMe(_MesCNC)]BF₄ > [PdMe(_MeCNC)]BF₄ > [PdMe(_tBuC^∧N^∧C)]BF₄ ≫ [PdMe(_tBuCNC)]BF₄ (not isolable). A comparison of the activity of the complexes as precatalysts in a model Heck coupling reaction shows greatest activity in those species bearing bulkier N-substituents, with complexes bearing _RC^∧N^∧C ligands generally more efficient precatalysts than those bearing _RCNC ligands.     

Glucagon receptor is required for long-term survival: A natural history study of the Mahvash disease in a murine model

Background and aimWe have described a novel Mahvash disease of hyperglucagonemia and pancreatic neuroendocrine tumors (PNETs) associated with an inactivating glucagon receptor mutation, and identified the glucagon receptor-deficient (Gcgr^?/?) mice as its murine model. We aim to elucidate the natural history of the rare Mahvash disease by long-term observation of the Gcgr^?/? mice.Materials and methodWild type (WT) (n = 52), heterozygous (n = 127), and Gcgr^?/? (n = 56) mice living under standard vivarium conditions were observed without specific treatments over 22 months. Autopsy was performed on dead animals.ResultsThe WT and heterozygous mice did not exhibit any measurable differences. The Gcgr^?/? mice became progressively lethargic and cachexic after 12 months. Random glucose levels were stable in WT and heterozygous mice but decreased with age in the Gcgr^?/? mice. At the end of observation, 28/56 Gcgr^?/?, 7/52 WT, and 24/127 heterozygous mice died. The survival curve of Gcgr^?/? mice began to separate from those of WT and heterozygous mice at 12 months and the survival difference widened with age. At 18 months, survival probability was 17% for Gcgr^?/? mice but 77% for WT and 81% for heterozygous mice. Autopsy revealed numerous PNETs up to 15 mm in diameter in most well-preserved Gcgr^?/? pancreata (17/20) but none in WT or heterozygous ones. Four Gcgr^?/? mice developed liver or subcutaneous metastasis.ConclusionThe untreated Mahvash disease may cause cachexia, severe hypoglycemia, and early death. Patients with Mahvash disease need to undergo life-long surveillance for PNETs. Functional glucagon receptor is thus required for long-term survival.     

Synthesis and PGE2 production inhibition of s-triazine derivatives as a novel scaffold in RAW 264.7 macrophage cells

We present the synthesis and biological evaluation of a collection of s-triazine derivatives as a novel scaffold of compounds with the capability to inhibit the PGE₂ production in LPS-induced RAW 264.7 macrophage cells. A total of 12 derivatives were synthesized and assayed for PGE₂ reduction at 10 μM concentration. Two compounds (7b and 7i) exhibiting >90% inhibition of PGE₂ production were found to have IC₅₀ values of 5.76 and 5.52 μM, respectively. They were counter screened for inhibition on COX-2 activity in a cell free assay. Specifically, compound 7i (R¹ = 4-Bn-Ph, R² = Cl, R³ = Ph, R⁵ = CO₂Me) was highly active in cells while maintaining little COX-2 inhibition (∼0% at 10 μM). Molecular docking study provides the possibility that compound 7i could inhibit PGE₂ production by blocking the PGH₂ binding site of mPGES-1 instead of COX-2 enzyme. Based on this result, our synthetic efforts will focus on intensive structure–activity relationship (SAR) study of s-triazine scaffold to discovery a potential PGE₂ synthesis inhibitor.     

Cytochrome c peroxidase is a mitochondrial heme-based H2O2 sensor that modulates antioxidant defense

Hydrogen peroxide (H₂O₂) is a key signaling molecule that also induces apoptosis. Thus, cells must rapidly sense and tightly control H₂O₂ levels. Well-characterized cellular responses to exogenous H₂O₂ involve oxidation of specific cytosolic protein-based thiols but sensing of H₂O₂ generated by mitochondrial respiration is less well described. Here we provide substantial biochemical evidence that the heme enzyme Ccp1 (cytochrome c peroxidase), which is targeted to the intermembrane space, functions primarily as a mitochondrial H₂O₂ sensing and signaling protein in Saccharomyces cerevisiae. Key evidence for a sensing role for Ccp1 is the significantly higher H₂O₂ accumulation in ccp1-null cells(ccp1Δ) vs ccp1^W191F cells producing the catalytically inactive Ccp1^W191F variant. In fact, intracellular H₂O₂ levels (ccp1Δ>wildtype >ccp1^W191F) correlate inversely with the activity of the mitochondrial (and peroxisomal) heme catalase, Cta1 (ccp1Δ<wildtype <ccp1^W191F). Mitochondrial Sod2 activity also varies in the three strains (ccp1Δ>wildtype >ccp1^W191F) and ccp1Δ cells exhibit low superoxide levels. Notably, Ccp1^W191F is a more persistent H₂O₂ signaling protein than wild-type Ccp1, and this enhanced mitochondrial H₂O₂ signaling decreases the mitochondrial fitness of ccp1^W191F cells. However, these cells are fully protected from a bolus (0.4 mM) of exogenous H₂O₂ added after 12 h of growth, whereas the viability of ccp1Δ cells drops below 20%, which additionally associates Ccp1 with Yap1-dependent H₂O₂ signaling. Combined, our results strongly implicate Ccp1, independent of its peroxidase activity, in mitochondrial H₂O₂ sensing and signaling to maintain reactive oxygen species homeostasis.     

Detection of nickel in maize roots: A novel nondestructive approach by reflectance spectroscopy and colorimetric models

In this paper, a novel method capable of assessing nickel (Ni) uptake in intact plant roots is proposed and validated. Dimethylglyoxime (DMG) was used to stain roots of seven-day-old maize (Zea mays L.) seedlings grown in solutions containing 0, 0.025, 0.1, 0.2, and 0.5 mM Ni²⁺. A nondestructive approach by using reflectance spectroscopy and CIE XYZ and CIE L*a*b* color systems was used to investigate their optical properties. The maximum intensity in reflectance spectra at 545 nm (A₅₄₅) was used to monitor the development of DMG–Ni complexes. The values of A₅₄₅ were polynomially related to the concentration of Ni²⁺ in the growing solution (R² = 0.98), and significant correlations were also observed between A₅₄₅ and the two indicators of phytotoxicity, namely, root growth inhibition (I) and variations in the shoot-to-root ratio (S/R). The variation of dominant wavelength (λ_d) and excitation purity (P_e) graphically derived from the x, y color gamut in the CIE XYZ system paralleled the two highest Ni concentrations. Most of the color parameters in the CIE L*a*b* system were closely related to both Ni²⁺ concentrations in plant growing medium and the values of (I) and (S/R) used here as markers of Ni toxicity. The revealed dependences confirm that the prelaminar method proposed here is capable of nondestructive estimating of Ni concentrations in intact root tissue. The values of A₅₄₅ in the reflectance spectra of stained roots and color parameters, namely, opponent redness–greenness (a^*), integral color difference (ΔE)^*, lightness color difference (ΔL)^*, and hue angle difference (ΔH)^*, showed the highest potential for diagnostic purposes.     

N-1 and C-3 substituted indole Schiff bases as selective COX-2 inhibitors: synthesis and biological evaluation

A group of N-1 and C-3 disubstituted-indole Schiff bases bearing an indole N-1 (R′ = H, CH₂Ph, COPh) substituent in conjunction with a C-3 –CHN–C₆H₄–4-X (X = F, Me, CF₃, Cl) substituent were synthesized and evaluated as inhibitors of cyclooxygenase (COX) isozymes (COX-1/COX-2). Within this group of Schiff bases, compounds 15 (R¹ = CH₂Ph, X = F), 17 (R¹ = CH₂Ph, X = CF₃), 18 (R¹ = COPh, X = F) and 20 (R¹ = COPh, X = CF₃) were identified as effective and selective COX-2 inhibitors (COX-2 IC₅₀’s = 0.32–0.84 μM range; COX-2 selectivity index (SI) = 113 to >312 range). 1-Benzoyl-3-[(4-trifluoromethylphenylimino)methyl]indole (20) emerged as the most potent (COX-1 IC₅₀ >100 μM; COX-2 IC₅₀ = 0.32 μM) and selective (SI >312) COX-2 inhibitor. Furthermore, compound 20 is a selective COX-2 inhibitor in contrast to the reference drug indomethacin that is a potent and selective COX-1 inhibitor (COX-1 IC₅₀ = 0.13 μM; COX-2 IC₅₀ = 6.9 μM, COX-2 SI = 0.02). Molecular modeling studies employing compound 20 showed that the phenyl CF₃ substituent attached to the CN spacer is positioned near the secondary pocket of the COX-2 active site, the CN nitrogen atom is hydrogen bonded (N?NH = 2.85 Å) to the H90 residue, and the indole N-1 benzoyl is positioned in a hydrophobic pocket of the COX-2 active site near W387.     

Characterization of subventricular zone-derived progenitor cells from mild and late symptomatic YAC128 mouse model of Huntington's disease

Huntington's disease (HD) is caused by an expansion of CAG repeats in the HTT gene, leading to expression of mutant huntingtin (mHTT) and selective striatal neuronal loss, frequently associated with mitochondrial dysfunction and decreased support of brain-derived neurotrophic factor (BDNF). New neurons derived from the subventricular zone (SVZ) are apparently not able to rescue HD pathological features. Thus, we analyzed proliferation, migration and differentiation of adult SVZ-derived neural stem/progenitor cells (NSPC) from mild (6 month-old (mo)) and late (10 mo) symptomatic HD YAC128 mice expressing full-length (FL)-mHTT versus age-matched wild-type (WT) mice. SVZ cells derived from 6 mo YAC128 mice exhibited higher migratory capacity and a higher number of MAP2 + and synaptophysin + cells, compared to WT cells; MAP2 labeling was enhanced after exposure to BDNF. However, BDNF-evoked neuronal differentiation was not observed in 10 mo YAC128 SVZ-derived cells. Interestingly, 6 mo YAC128 SVZ-derived cells showed increased intracellular Ca²⁺ levels in response to KCl, which was potentiated by BDNF, evidencing the presence of differentiated neurons. In contrast, KCl depolarization-induced intracellular Ca²⁺ increase in 10 mo YAC128 SVZ-derived cells was shown to be increased only in BDNF-treated YAC128 SVZ-derived cells, suggestive of decreased differentiation capacity. In addition, BDNF-untreated NSPC from 10 mo YAC128 mice exhibited lower mitochondrial membrane potential and increased mitochondrial Ca²⁺ accumulation, in relation with NSPC from 6 mo YAC128 mice. Data evidence age-dependent reduced migration and decreased acquisition of a neuronal phenotype, accompanied by decreased mitochondrial membrane potential in SVZ-derived cells from YAC128 mice through HD symptomatic phases.     

Nanomechanical phenotype of chondroadherin-null murine articular cartilage

Chondroadherin (CHAD), a class IV small leucine rich proteoglycan/protein (SLRP), was hypothesized to play important roles in regulating chondrocyte signaling and cartilage homeostasis. However, its roles in cartilage development and function are not well understood, and no major osteoarthritis-like phenotype was found in the murine model with CHAD genetically deleted (CHAD^−/−). In this study, we used atomic force microscopy (AFM)-based nanoindentation to quantify the effects of CHAD deletion on changes in the biomechanical function of murine cartilage. In comparison to wild-type (WT) mice, CHAD-deletion resulted in a significant ≈ 70–80% reduction in the indentation modulus, E_ind, of the superficial zone knee cartilage of 11 weeks, 4 months and 1 year old animals. This mechanical phenotype correlates well with observed increases in the heterogeneity collagen fibril diameters in the surface zone. The results suggest that CHAD mainly plays a major role in regulating the formation of the collagen fibrillar network during the early skeletal development. In contrast, CHAD-deletion had no appreciable effects on the indentation mechanics of middle/deep zone cartilage, likely due to the dominating role of aggrecan in the middle/deep zone. The presence of significant rate dependence of the indentation stiffness in both WT and CHAD^−/− knee cartilage suggested the importance of both fluid flow induced poroelasticity and intrinsic viscoelasticity in murine cartilage biomechanical properties. Furthermore, the marked differences in the nanomechanical behavior of WT versus CHAD^−/− cartilage contrasted sharply with the relative absence of overt differences in histological appearance. These observations highlight the sensitivity of nanomechanical tools in evaluating structural and mechanical phenotypes in transgenic mice.     

Hexokinase—A limiting factor in lipid production from fructose in Yarrowia lipolytica

Microbial biolipid production has become an important part of making biofuel production economically feasible. Genetic engineering has been used to improve the ability of Yarrowia lipolytica, an oleaginous yeast, to produce lipids using glucose-based media. However, few studies have examined lipid accumulation by Y. lipolytica׳s ability to utilize other hexose sugars, and as of yet, the rate-limiting steps in this process are unidentified. In this study, we investigated the de novo accumulation of lipids by Y. lipolytica when grown in glucose, fructose, and sucrose. Three Y. lipolytica wild-type (WT) strains of varied origin differed significantly in their lipid production, growth, and fructose utilization. Hexokinase (ylHXK1p) activity partially explained these differences. Overexpression of the ylHXK1 gene led to increased hexokinase activity (6.5–12 times higher) in the mutants versus the WT strains; a pronounced reduction in cell filamentation in mutants grown in fructose-based media; and improved biomass production, particularly in the mutant whose parent had shown the lowest growth capacity in fructose (French strain W29). All mutants showed improved lipid yield and production when grown on fructose, although the effect was strain dependent (23–55% improvement). Finally, we overexpressed ylHXK1 in a highly modified strain of Y. lipolytica W29 engineered to optimize oil production. This modification was combined with Saccharomyces cerevisiae invertase gene expression to evaluate the resulting mutant׳s ability to produce lipids using cheap industrial substrates, namely sucrose (a major component of molasses). Sucrose turned out to be a better substrate than either of its building blocks, glucose or fructose. Over its 96 h of growth in the bioreactors, this highly modified strain produced 9.15 g L⁻¹ of lipids, yielding 0.262 g g⁻¹ of biomass.     

A multi-tolerant low molecular weight mannanase from Bacillus sp. CSB39 and its compatibility as an industrial biocatalyst

Bacillus sp. CSB39, isolated from popular traditional Korean food (Kimchi), produced a low molecular weight, thermostable mannanase (MnCSB39); 571.14 U/mL using locust bean gum galactomannan as a major substrate. It was purified to homogeneity using a simple and effective two-step purification strategy, Sepharose CL-6B and DEAE Sepharose Fast Flow, which resulted in 25.47% yield and 19.32-fold purity. The surfactant-, NaCl-, urea-, and protease-tolerant monomeric protein had a mass of ∼30 kDa as analyzed by SDS-PAGE and galactomannan zymography. MnCSB39 was found to have optimal activity at pH 7.5 and temperature of 70 °C. The enzyme showed ˃55% activity at 5.0–15% (w/v) NaCl, and ˃93% of the initial activity after incubation at 37 °C for 60 min. Trypsin and proteinase K had no effect on MnCBS39. The enzyme showed ˃80% activity in up to 3 M urea. The N-terminal amino acid sequence, ALKGDGX, did not show identity with reported mannanases, which suggests the novelty of our enzyme. Activation energy for galactomannan hydrolysis was 26.85 kJmol⁻¹ with a K_cat of 142.58 × 10⁴ s⁻¹. MnCSB39 had K_m and V_max values of 0.082 mg/mL and 1099 ± 1.0 Umg⁻¹, respectively. Thermodynamic parameters such as ΔH, ΔG, ΔS, Q₁₀, ΔG_E-S, and ΔG_E-T supported the spontaneous formation of products and the high hydrolytic efficiency and feasibility of the enzymatic reaction, which strengthen its novelty. MnCSB39 activity was affected by metal ions, modulators, chelators, and detergents. Mannobiose was the principal end-product of hydrolysis. Bacillus subtilis CSB39 produced a maximum of 1524.44 U mannanase from solid state fermentation of 1 g wheat bran. MnCSB39 was simple to purify, was active at a wide pH and temperature range, multi-stress tolerant and catalyzes a thermodynamically possible reaction, characteristics that suggests its suitability for application as an industrial biocatalyst.     

Methylnickel compounds containing 2-phosphinylethanolato ligands – Syntheses,properties, and ethene coupling reactions

Combining dimethylphosphinylethanols HO(R¹R²)CCH₂PMe₂ (1: R¹ = R² = C₆H₅; 2: R¹ = R² = 4-OMe–C₆H₄; 5: R¹ = R² = 4-NMe₂–C₆H₄) with methyl(methoxo)(trimethylphosphine)nickel gave mononuclear methyl(trimethylphosphine)nickel(chelate) compounds 7–9. Ligand 6 (R¹ = Me, R² = 4-OMe–C₆H₅) afforded a dinuclear methylnickel compound 14. By reacting (TMEDA)lithium-dimethylphosphinylmethanide with ketones OC(R¹R²), the dimethylphosphinylethanols HO(R¹R²)CCH₂PMe₂ (3: R¹R² = 9-fluorenyl; 4: R¹ = H, R² = C₆H₅) were synthesized as prechelate ligands. Under otherwise similar conditions, the fluorenyl substituted anion in 3 gave rise to a mononuclear complex 10 which was found to act as a source of trimethylphosphine forming dinuclear 11 and at the same time to act as an acceptor of trimethylphosphine forming pentacoordinate 10 · PMe₃. Ni(COD)(PMe₃)₂ was used as a scavenger of PMe₃ in converting 8 or 9 to the dinuclear methylnickel compounds 12 and 13, respectively. Modifying the P,O chelating unit of a methyl nickel compound by introducing 2-phosphinylethanolato ligands leads to novel single-component catalysts for ethene oligomerization showing moderate reactivity and thermal stability.     

Climatic dependency of soil organic carbon isotopic composition along the S–N Transect from 34°N to 52°N in central-east Asia

We explored the relationships between surface-soil (1–20 cm) organic carbon isotopic signatures and associated climatic factors in central-east Asia in an attempt to develop transfer functions that can be used to retrieve the paleoclimatic information stored in the thick eolian–paleosol sequences within the area. Our analysis shows that the negative correlation between the surface-soil organic δ¹³C values and the mean annual precipitation is robust (R² = 0.453; n = 196; p < 0.05) and the negative correlation with the growing-season (April–September) precipitation is more significant (R² = 0.4966; n = 196; p < 0.05). Our study further shows that the positive correlation between the surface-soil organic δ¹³C values and mean growing-season aridity is most significant (R² = 0.5805; n = 196; p < 0.05). We have smoothed both the organic δ¹³C values and the mean growing-season aridity values using a 3-point moving-window average-filter method in an attempt to remove some of random errors and found that the positive correlation between the two is further increased (R² =  0.7784; n =  192; p < 0.05). These robust linear relationships demonstrate their value in reconstructing paleoclimate changes in the study area. The documented climatic dependency of the surface-soil carbon isotopic composition in the study area might have resulted both from the humidity-related isotopic enrichment processes of the dominant C₃ plants (stomatal conductance and photosynthetic discrimination) and from the aridity-related abundance of C₄ plants (mainly Chenopodiaceae species) along the S–N bioclimatic gradient.     

Effects of shell morphological traits on the weight trait of the orange strain of the Manila clam

A new strain of Manila clam with orange shell color was produced after selection within a full-sib family for two generations. In the present study, the shell length, height, and width, and the live body weight of the orange strain were measured, and their correlation coefficients were calculated. The shell morphological traits were used as independent variables, and the live body weight was used as the dependent variable for calculating the path coefficients, correlation index, and determination coefficients. The results showed that the correlation coefficients between each shell morphological trait and the live body weight were all highly significant (P < 0.01). The correlation indices (R²) of morphological traits against the live body weight of clams were larger than 0.85, indicating that the morphology traits were the main factors affecting the body weight. Multiple regression equations were obtained to estimate shell length X₁ (cm), shell height X₂ (cm), and shell width X₃ (cm) against live body weight Y (g): Y = ? 2.62 + 0.34 X₁ + 0.145 X₂, (X₁ < 0.05, X₂ < 0.05). The results suggest that the shell length could be used as the main trait for selective breeding and could indirectly make a large improvement in the weight trait.