Metal complexes of carboxamidrazone analogs as antitubercular agents. 1. Synthesis,X-ray crystal-structures,spectroscopic properties and antimycobacterial activity against Mycobacterium tuberculosis H(37)Rv

N¹-Benzylidene-pyridine carboxamidrazones and their metal conjugates have emerged as a new class of potential antimycobacterial agents. Nine such carboxamidrazone analogs (L₁–L₉) along with their Cu(II) (MC₁–MC₉) and Fe(III) (MC₁₀–MC₁₈) complexes were synthesized. Single crystal X-ray structures of copper complexes MC₁ and MC₅ were determined which suggest slightly distorted square planer geometries for copper complexes and octahedral geometries for ferric compounds. All compounds were evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H₃₇Rv. The results show 32–64-fold enhancement in antitubercular activity upon copper complexation.     

Improvement of a mammalian cell culture process by adaptive,model-based dialysis fed-batch cultivation and suppression of apoptosis

Both conventional and genetic engineering techniques can significantly improve the performance of animal cell cultures for the large-scale production of pharmaceutical products. In this paper, the effect of such techniques on cell yield and antibody production of two NS0 cell lines is presented. On the one hand, the effect of fed-batch cultivation using dialysis is compared to cultivation without dialysis. Maximum cell density could be increased by a factor of ~5–7 by dialysis fed-batch cultivation. On the other hand, suppression of apoptosis in the NS0 cell line 6A1 bcl-2 resulted in a prolonged growth phase and a higher viability and maximum cell density in fed-batch cultivation in contrast to the control cell line 6A1 (100)3. These factors resulted in more product formation (by a factor ~2). Finally, the adaptive model-based OLFO controller, developed as a general tool for cell culture fed-batch processes, was able to control the fed-batch and dialysis fed-batch cultivations of both cell lines.Abbreviations A membrane area (dm²) - c _Glc,F glucose concentration in nutrient feed (mmol L^–1) - c _Glc,FD glucose concentration in dialysis feed (mmol L^–1) - c _Glc,i glucose concentration in inner reactor chamber (mmol L^–1) - c _Glc,o glucose concentration in outer reactor chamber (dialysis chamber) (mmol L^–1) - c _Lac,FD lactate concentration in dialysis feed (mmol L^–1) - c _Lac,i lactate concentration in inner reactor chamber (mmol L^–1) - c _Lac,o lactate concentration in outer reactor chamber (dialysis chamber) (mmol L^–1) - c _LS,FD limiting substrate concentration in dialysis feed (mmol L^–1) - c _LS,i limiting substrate concentration in inner reactor chamber (mmol L^–1) - c _LS,o limiting substrate concentration in outer reactor chamber (dialysis chamber) (mmol L^–1) - c _Mab monoclonal antibody concentration (mg L^–1) - F _D feed rate of dialysis feed (L h^–1) - F _Glc feed rate of nutrient concentrate feed (L h^–1) - K _d maximum death constant (h^–1) - k _d,LS death rate constant for limiting substrate (mmol L^–1) - k _Glc monod kinetic constant for glucose uptake (mmol L^–1) - k _Lac monod kinetic constant for lactate uptake (mmol L^–1) - k _LS monod kinetic constant for limiting substrate uptake (mmol L^–1) - K _Lys cell lysis constant (h^–1) - K _S,Glc monod kinetic constant for glucose (mmol L^–1) - K _S,LS monod kinetic constant for limiting substrate (mmol L^–1) - µ cell-specific growth rate (h^–1) - µ _d cell-specific death rate (h^–1) - µ _d,min minimum cell-specific death rate (h^–1) - µ _max maximum cell-specific growth rate (h^–1) - P _Glc membrane permeation coefficient for glucose (dm h^–1) - P _Lac membrane permeation coefficient for lactate (dm h^–1) - P _LS membrane permeation coefficient for limiting substrate (dm h^–1) - q _Glc cell-specific glucose uptake rate (mmol cell^–1 h^–1) - q _Glc,max maximum cell-specific glucose uptake rate (mmol cell^–1 h^–1) - q _Lac cell-specific lactate uptake/production rate (mmol cell^–1 h^–1) - q _Lac,max maximum cell-specific lactate uptake rate (mmol cell^–1 h^–1) - q _LS cell-specific limiting substrate uptake rate (mmol cell^–1 h^–1) - q _LS,max maximum cell-specific limiting substrate uptake rate (mmol cell ^–1 h^–1) - q _Mab cell-specific antibody production rate (mg cell^–1 h^–1) - q _MAb,max maximum cell-specific antibody production rate (mg cell^–1 h^–1) - t time (h) - V _i volume of inner reactor chamber (culture chamber) (L) - V _o volume of outer reactor chamber (dialysis chamber) (L) - X _t total cell concentration (cells L^–1) - X viable cell concentration (cells L^–1) - Y _Lac/Glc kinetic production constant (stoichiometric ratio of lactate production and glucose uptake) (–)     

Synthesis,Characterization, Antimicrobial and Antimalarial Activities of Azines Based Schiff Bases and their Pd(II) Complexes

Herein, we report synthesis, characterization, antimicrobial and antimalarial activities of azines Schiff base ligands (L¹−L⁴) and their palladium (II) complexes ( C¹−C⁴ ) of [Pd(L)(OAc)₂] type. The azine ligands (L¹−L⁴) were prepared by condensation of carbonyl compounds with hydrazine hydrate and their complexes by the reaction of palladium acetate with L¹−L⁴ ligands in 1 : 1 molar ratio. The prepared ligands and their complexes were characterized by spectral characterization using ¹H &¹³C-NMR, FT-IR and mass spectral studies, which revealed that the ligands coordinates via azomethine nitrogen and heteroatom or aryl carbon with palladium. Moreover, Schiff bases and their palladium (II) complexes have been screened for their antibacterial (S. aureus, B. subtillis, and S. typhi, P. aeruginosa), antifungal (C. albicans, A. niger, and A. clavatus) and antimalarial (P. falciparum) activities. The Schiff base L⁴ showed good results for antibacterial against S. aureus (MIC, 50 μg/mL) and antimalarial against P. falciparum (IC₅₀, 0.83 μg/mL). The complex C¹ showed best antibacterial activity (MIC, 62.5 μg/mL) against S. typhi and the complex C⁴ exhibited remarkable antimalarial activity (IC₅₀, 0.42 μg/mL) among the tested compounds. Thus, azines based ligands and their Pd complexes can be good antimicrobial and antimalarial agents if explored further.     

Determination of cell lysis and death kinetics in continuous hybridoma cultures from the measurement of lactate dehydrogenase release

The death of the hybridoma VO 208 in a continuous culture at pH 7 and 6.8 was investigated by measuring both the appearance of visible dead cells which do not exclude the trypan blue dye and the release of lactate dehydrogenase (LDH) in the culture medium. The intracellular LDH was found to be completely released either when live cells lysed or when they were transformed into visible dead cells. No significant lysis of blue dead cells could be observed at the two different pH. Using a LDH balance over the culture system, cell lysis was found negligible at pH 7, but accounted for 20% of the total cell death at pH 6.8. A methodology is proposed to evaluate the rate constants of hybridoma lysis and total death. For the investigated cell line in continuous culture, the calculated total cell death rate constant was found to increase from 0.002 h^–1 to 0.01 h^–1 when decreasing the pH from 7 to 6.8.Abbreviations D dilution rate (h^–1) - k_b specific trypan-blue dead cells appearance rate (h^–1) - k_L specific lysis rate of viable cells (h^–1) - k_d specific death rate (h-1) - LDH₀ lactate dehydrogenase activity in the feed culture medium (IU.l^–1) - LDH lactate dehydrogenase activity in the outlet culture medium (IU.l^–1) - LDH_i intracellular lactate dehydrogenase activity of viable cells (IU.10^–9 cells) - r_LDH total rate of LDH release (IU.h^–1.L^–1) - r_b transformation rate of viable cells into blue dead cells (10⁹ cells.h^–1.L^–1) - x_v viable cell concentration (10⁹ cells.l^–1) - x_b trypan-blue dead cell concentration (10⁹ cells.l^–1)     

Effect of pH,aeration and sucrose feeding on the invertase activity of intactS. cerevisiae cells grown in sugarcane blackstrap molasses

S. cerevisiae was grown in a blackstrap molasses containing medium in batch and fed-batch cultures. The following parameters were varied: pH (from 4.0 to 6.5), dissolved oxygen (DO) (from 0 to 5.0 mg O₂L^–1) and sucrose feeding rate. When glucose concentration (S) was higher than 0.5 g L^–1 a reduction in the specific invertase activity of intact cells (v) and an oscillatory behavior of v values during fermentation were observed. Both the invertase reduction and the oscillatory behavior of v values could be related to the glucose inhibitory effect on invertase biosynthesis. The best culture conditions for attainingS. cerevisiae cells suitable for invertase production were: temperature=30°C; pH=5.0; DO=3.3 mg O₂L^–1; (S)=0.5 g L^–1 and sucrose added into the fermenter according to the equations: (V–V_o)=t²/16 or (V–V_o)=(V_f–V_o)·(e^0.6t–1)/10.This work was supported by FAPESP     

Copper (II) and zinc (ii) metal-based salicyl-, furanyl-, thienyl- and pyrrolyl-derived ONNO,NNNO, ONNS & NNNS donor asymmetrically mixed schiff-bases with antibacterial and antifungal potentials

A new series of asymmetric salicyl-, furanyl-, thienyl- and pyrrolyl-derived ONNO, NNNO, ONNS & NNNS donor antibacterial and antifungal Schiff-bases and their copper(II) and zinc(II) metal complexes have been synthesized and characterized. IR spectra indicated the ligands to act as quartdentate towards divalent metal ions via two azomethine-N, deprotonated-O of salicyl, furanyl-O, thienyl-S and/or pyrrolyl-N. The magnetic moments and electronic spectral data suggest octahedral geometry for Cu(II) and Zn(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against B. cereus, C. diphtheriae, E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa, S. typhi, S. dysenteriae and S. aureus strains and for in-vitro antifungal activity against T. schoenleinii, C. glabrata, P. boydii, C. albicans, A. niger, M. canis and T. mentagrophytes. The results of these studies show the metal complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties. Eight compounds, L₄, (1), (7), (8), (11), (17), (19) and (23) displayed potent cytotoxic activity with LD₅₀ = 1.445 × 10^{? 3}, 1.021 × 10^{? 3}, 7.478 × 10^{? 4}, 8.566 × 10^{? 4}, 1.028 × 10^{? 3}, 9.943 × 10^{? 4}, 8.730 × 10^{? 4} and 1.124 × 10^{? 3} M respectively, against Artemia salina.     

Synthesis, characterization and bioactivity of two novel trinuclear Cu(II)/Ni(II) complexes with pentadentate ligand N-2-methyl-acryloyl-salicylhydrazide

Two new trinuclear complexes, Cu₃L₂(py)₂ (1) and Ni₃L₂(py)₄ (2), have been synthesized and characterized, where L³⁻ is N-2-methyl-acryloyl-salicylhydrazidate. Central metal ion and two terminal metal ions in the two complexes are combined by two bridging deprotonated L³⁻ ligands, forming a bent trinuclear structure unit with an M-N-N-M-N-N-M core. The bent angles in complexes 1 and 2 are 167.6(1)° and 75.4(1)°, respectively. Three nickel ions in compound 2 exhibit alternating square-planar and octahedral geometries, while three copper ions in compound 1 follow square-planar mode. The studies in solution integrity and stability of compounds 1 and 2 show they are soluble and stable in DMF. UV-Vis titrations demonstrate compound 1 is stable in DMF even in the presence of excess metal ions. Antibacterial screening data indicate the two compounds all have stronger antimicrobial activities against the tested microorganisms than ligand. The trinuclear copper compound 1 is more active than monocopper compounds in the previous study, and the trinuclear nickel compound 2 is less active than tetranuclear nickel compound in the previous study.     

Complexes of 2-acetyl-gamma-butyrolactone and 2-furancarbaldehyde thiosemicarbazones: antibacterial and antifungal activity

Cobalt, nickel, copper and zinc coordination compounds of two thiosemicarbazones with general composition ML₂ (L: monodeprotonated ligand corresponding to 2-acetyl-γ-butyrolactone thiosemicarbazone, HL¹, and 2-furancarbaldehyde thiosemicarbazone, HL²) and also complexes with general composition MCl₂(HL²) were synthesized (except [NiCl₂(HL²)] and [Co(L²)₂]). The interaction of CuCl₂ with HL² gave [CuCl(HL²)], a copper(I) complex. The ligands and metal complexes were characterized by IR, ¹H and ¹³C NMR spectroscopy, and magnetic susceptibility measurements. The crystal structure of [Ni(L²)₂] · 2dmso was determined and a trans-square planar coordination of the two κ²-N,S chelate rings forming polymeric strips through H-bonds with dmso was observed. Actually, in all the reported complexes both ligands behaved as κ²-N,S chelates, except in the case of [Co(L¹)₂] in which HL¹ is tridentate κ³-N,S,O. The antimicrobial properties of all compounds were studied using a wide spectrum of bacterial and fungal strains. The copper complexes of HL² were the most active against all strains, including dermatophytes and phytopathogenic fungi. Most of the studied compounds, especially [Cu(L¹)₂], presented good activity against Haemophilus influenzae, a very harmful bacterium to humans.     

Modeling of the pyruvate production with<Emphasis Type="Italic"> Escherichia coli</Emphasis> in a fed-batch bioreactor

A family of 10 competing, unstructured models has been developed to model cell growth, substrate consumption, and product formation of the pyruvate producing strain Escherichia coli YYC202 ldhA::Kan strain used in fed-batch processes. The strain is completely blocked in its ability to convert pyruvate into acetyl-CoA or acetate (using glucose as the carbon source) resulting in an acetate auxotrophy during growth in glucose minimal medium. Parameter estimation was carried out using data from fed-batch fermentation performed at constant glucose feed rates of q_VG=10 mL h^–1. Acetate was fed according to the previously developed feeding strategy. While the model identification was realized by least-square fit, the model discrimination was based on the model selection criterion (MSC). The validation of model parameters was performed applying data from two different fed-batch experiments with glucose feed rate q_VG=20 and 30 mL h^–1, respectively. Consequently, the most suitable model was identified that reflected the pyruvate and biomass curves adequately by considering a pyruvate inhibited growth (Jerusalimsky approach) and pyruvate inhibited product formation (described by modified Luedeking–Piret/Levenspiel term).List of symbols c_A acetate concentration (g L^–1) - c_A,0 acetate concentration in the feed (g L^–1) - c_G glucose concentration (g L^–1) - c_G,0 glucose concentration in the feed (g L^–1) - c_P pyruvate concentration (g L^–1) - c_P,max critical pyruvate concentration above which reaction cannot proceed (g L^–1) - c_X biomass concentration (g L^–1) - K_I inhibition constant for pyruvate production (g L^–1) - K_I^A inhibition constant for biomass growth on acetate (g L^–1) - K_P saturation constant for pyruvate production (g L^–1) - K_P inhibition constant of Jerusalimsky (g L^–1) - K_S^A Monod growth constant for acetate (g L^–1) - K_S^G Monod growth constant for glucose (g L^–1) - m_A maintenance coefficient for growth on acetate (g g^–1 h^–1) - m_G maintenance coefficient for growth on glucose (g g^–1 h^–1) - n constant of extended Monod kinetics (Levenspiel) (–) - q_V volumetric flow rate (L h^–1) - q_VA volumetric flow rate of acetate (L h^–1) - q_VG volumetric flow rate of glucose (L h^–1) - r_A specific rate of acetate consumption (g g^–1 h^–1) - r_G specific rate of glucose consumption (g g^–1 h^–1) - r_P specific rate of pyruvate production (g g^–1 h^–1) - r_P,max maximum specific rate of pyruvate production (g g^–1 h^–1) - t time (h) - V reaction (broth) volume (L) - Y_P/G yield coefficient pyruvate from glucose (g g^–1) - Y_X/A yield coefficient biomass from acetate (g g^–1) - Y_X/A,max maximum yield coefficient biomass from acetate (g g^–1) - Y_X/G yield coefficient biomass from glucose (g g^–1) - Y_X/G,max maximum yield coefficient biomass from glucose (g g^–1) - growth associated product formation coefficient (g g^–1) - non-growth associated product formation coefficient (g g^–1 h^–1) - specific growth rate (h^–1) - _max maximum specific growth rate (h^–1)     

Copper(II) complexes of coumarin-derived Schiff bases and their anti-Candida activity

The condensation of 7-amino-4-methyl-coumarin (1) with a number of substituted salicylaldehydes yielded a series of Schiff bases (2a–2k) in good yields. Subsequent reaction of these ligands with copper(II) acetate yielded Cu(II) complexes (3a–3k) and some were characterised using X-ray crystallography. All of the free ligands and their metal complexes were tested for their anti-Candida activity. A number of the ligands and complexes exhibited anti-Candida activity comparable to that of the commercially available antifungal drugs, ketoconazole and Amphotericin B.     

Metabolic and cardiovascular adaptations in the western chipmunks, genusEutamias

Summary The metabolic and cardiac responses to temperature were studied in two species (four subspecies) of western chipmunks (genusEutamias), inhabiting boreal and alpine environments. A specially designed (Fig. 1) implantable biopential radiotransmitter was used to measure heart rate in unrestrained animals. The estimated basal metabolic rates (EBMR) were 1.78 (E. minimus borealis), 1.64 (E. m. oreocetes), 1.50 (E. m. operarius), and 1.69 ml O₂ g^–1 h^–1 (E. amoenus luteiventris), or 839, 752, 698, and 628 ml O₂ kg^–0.75 h^–1, respectively, for the four subspecies (Table 1). The two alpine species (E.m.or. andE.m.op.) had significantly lower EBMR than both of their boreal counterparts. The EBMR from all animals are 120–135% of the predicted values based on body weights of the animals. The thermal neutral zone for the four subspecies ranged from 23.5 to 32°C and the minimum thermal conductances were 0.113, 0.111, 0.112 and 0.112 ml O₂ g^–1 h^–1 °C^–1, respectively, or 54.4, 54.0, 50.4 and 52.1 ml O₂ kg^–0.75 h^–1 °C^–1, respectively (Fig. 2). No interspecific diffence in conductance was observed. These values are 72 to 85% of their weight specific values. The body temperature ranged between 35.0 and 39.5°C and was usually maintained between 36 and 38°C in all subspecies between ambient temperatures of 3 and 32°C. The estimated basal heart rates were 273, 296, 273 and 264 beats/min, respectively, for the four subspecies, 49–55% of their predicted weight specific values. The resultant oxygen pulses (metabolic rate/heart rate) were 5.49, 4.50, 4.48 and 5.56×10^–3 ml O₂/beat, respectively, which are 2 to 2.4 times their weight specific values (Table 2).The observed reduction of basal heart rate without the corresponding decreases of basal metabolic rate and body temperature indicate sufficient compensatory increases in stroke volume and/or A-V oxygen difference at rest. Such cardiovascular modifications provide extra reserves when demand for aerobic metabolism rises during bursts of activity typically observed in the western chipmunk.Abbreviations A-V arterio-venous - EBMR estimated basal metabolic rate (ml O₂ g^–1 h^–1) - HR heart rate (beats/min) - MR metabolic rate (ml O₂ g^–1 h^–1) - OP oxygen pulse (ml O₂/heart beat) - T_a, T_b ambient and body temperature (°C)     

η-N-succinimidato complexes of iron, molybdenum and tungsten as reversible inhibitors of papain

Recently we have found that the metallocarbonyl complexes (η⁵-C₅H₅)M(CO)_x(η¹-N-maleimidato) (M = Fe, Mo, W; x = 2 or 3) bearing a maleimide function were irreversible inhibitors of the enzyme papain. To get further insight into the binding mechanism of these compounds we synthesized the related complexes (η⁵-C₅H₅)M(CO)_x(η¹-N-succinimidato) (M = Fe, Mo, W; x = 2 or 3) that lacked the ethylenic bond responsible for alkylation of the cysteine 25 thiol group in the papain‘s catalytic pocket. We performed kinetic studies of the interaction of the synthesized complexes towards papain. We found that they act as reversible inhibitors of the enzyme with IC₅₀ values in the range 480–1700 μM. Docking experiments confirmed binding of these complexes to the enzyme’s catalytic pocket.     

Copper(II) Complexes Derived from Schiff Bases Containing 4-Methylbenzylamine as a Core Unit: Cytotoxicity,pBR322-DNA Studies,Biological Assays,and Quantum Chemical Parameters

Bivalent copper complexes, [Cu(SB¹)₂] 1 (SB¹=(2-(4-methylbenzylimino)methyl)-5-methylphenol, [Cu(SB²)₂] 2 (SB²=(2-(4-methylbenzylimino)methyl)-4-bromolphenol), and [Cu(SB³)₂] 3 (SB³=(2-(4-methylbenzylimino)methyl)-4,6-dibromophenol) were synthesized using the Schiff bases prepared from 4-methylbenzylamine (p-tolylmethanamine). These were characterized using a variety of spectro-analytical methods. For all copper complexes, a square planar geometry was determined through spectral analyses. Utilizing molecular orbital energies, the stability of the copper complexes was calculated from quantum chemical characteristics. The kinetic and thermal degradation parameters were calculated from the thermograms. Studies on DNA binding interactions, such as UV absorption and emission, have shown that the manner of DNA binding is intercalative, and the binding constant (K_b) order is 3 > 2 > 1 . Under oxidative and photolytic techniques, the copper complexes outperform the parent Schiff bases in their ability to cleave double-stranded pBR322 DNA. When tested for cytotoxicity on the KB3 and MCF7 cell lines, complexes displayed greater activity than their parent ligands. Studies on the complexes′ in-vitro antibacterial and antioxidant activity showed that they are significantly more powerful than the parent ligands.     

Fed-batch production of baker's yeast using millet (Pennisetum typhoides) flour hydrolysate as the carbon source

A fermentation medium based on millet (Pennisetum typhoides) flour hydrolysate and a four-phase feeding strategy for fed-batch production of baker's yeast,Saccharomyces cerevisiae, are presented. Millet flour was prepared by dry-milling and sieving of whole grain. A 25% (w/v) flour mash was liquefied with a thermostable 1,4--d-glucanohydrolase (EC 3.2.1.1) in the presence of 100 ppm Ca²⁺, at 80°C, pH 6.1–6.3, for 1 h. The liquefied mash was saccharified with 1,4--d-glucan glucohydrolase (EC 3.2.1.3) at 55°C, pH 5.5, for 2 h. An average of 75% of the flour was hydrolysed and about 82% of the hydrolysate was glucose. The feeding profile, which was based on a model with desired specific growth rate range of 0.18–0.23 h^–1, biomass yield coefficient of 0.5 g g^–1 and feed substrate concentration of 200 g L^–1, was implemented manually using the millet flour hydrolysate in test experiments and glucose feed in control experiments. The fermentation off-gas was analyzed on-line by mass spectrometry for the calculation of carbon dioxide production rate, oxygen up-take rate and the respiratory quotient. Off-line determination of biomass, ethanol and glucose were done, respectively, by dry weight, gas chromatography and spectrophotometry. Cell mass concentrations of 49.9–51.9 g L^–1 were achieved in all experiments within 27 h of which the last 15 h were in the fedbatch mode. The average biomass yields for the millet flour and glucose media were 0.48 and 0.49 g g^–1, respectively. No significant differences were observed between the dough-leavening activities of the products of the test and the control media and a commercial preparation of instant active dry yeast. Millet flour hydrolysate was established to be a satisfactory low cost replacement for glucose in the production of baking quality yeast.Nomenclature C _ox Dissolved oxygen concentration (mg L^–1) - CPR Carbon dioxide production rate (mmol h^–1) - C _s0 Glucose concentration in the feed (g L^–1) - C _s Substrate concentration in the fermenter (g L^–1) - C _s.crit Critical substrate concentration (g L^–1) - E Ethanol concentration (g L^–1) - F _s Substrate flow rate (g h^–1) - i Sample number (–) - K _e Constant in Equation 6 (g L^–1) - K _o Constant in Equation 7 (mg L^–1) - K _s Constant in Equation 5 (g L^–1) - m Specific maintenance term (h^–1) - OUR Oxygen up-take rate (mmol h^–1) - q _ox Specific oxygen up-take rate (h^–1) - q _ox.max Maximum specific oxygen up-take rate (h^–1) - q _p Specific product formation rate (h^–1) - q _s Specific substrate up-take rate (g g^–1 h^–1) - q _s.max Maximum specific substrate up-take rate (g g^–1 h^–1) - RQ Respiratory quotient (–) - S Total substrate in the fermenter at timet (g) - S ₀ Substrate mass fraction in the feed (g g^–1) - t Fermentation time (h) - V Instantaneous volume of the broth in the fermenter (L) - V ₀ Starting volume in the fermenter (L) - V _si Volume of samplei (L) - x Biomass concentration in the fermenter (g L^–1) - X ₀ Total amount of initial biomass (g) - X _t Total amount of biomass at timet (g) - Y _p/s Product yield coefficient on substrate (–) - Y _x/e Biomass yield coefficient on ethanol (–) - Y _x/s Biomass yield coefficient on substrate (–) Greek letters Moles of carbon per mole of yeast (–) - Moles of hydrogen atom per mole of yeast (–) - Moles of oxygen atom per mole of yeast (–) - Moles of nitrogen atom per mole of yeast (–) - Specific growth rate (h^–1) - _crit Critical specific growth rate (h^–1) - _E Specific ethanol up-take rate (h^–1) - _max.E Maximum specific ethanol up-take rate (h^–1)     

Synthesis and glycogen phosphorylase inhibitory activity of N-(β-d-glucopyranosyl)amides possessing 1,4-benzodioxane moiety

A series of N-(β-d-glucopyranosyl)amides 5d–i were synthesized by PMe₃ mediated Staudinger reaction of O-peracetylated β-d-glucopyranosyl azide (1) followed by acylation with carboxylic acids 3d–i and subsequent Zemplén deacetylation. The new compounds were tested for their inhibitory activity against rabbit muscle glycogen phosphorylase and the structure–activity relationships of these compounds are also discussed in this paper.     

Theoretical,in Vitro Antiproliferative,and in Silico Molecular Docking and Pharmacokinetics Studies of Heteroleptic Nickel(II) and Copper(II) Complexes of Thiosemicarbazone-Based Ligands and Pefloxacin

Twelve new heteroleptic nickel(II) and copper(II) complexes of the type [M(L^1–6)(Pfx)₂] ( 1 – 12 ), where L^1–6=2-benzylidenehydrazinecarbothioamide (L¹), 2-benzylidene-N-methylhydrazinecarbothioamide (L²), 2-benzylidene-N-phenylhydrazinecarbothioamide (L³), 2-(4-methylbenzylidene)hydrazinecarbothioamide (L⁴), 2-(4-methylbenzylidene)-N-methylhydrazinecarbothioamide (L⁵) and 2-(4-methylbenzylidene)-N-phenylhydrazinecarbothioamide (L⁶), Pfx=pefloxacin and M=Ni(II) or Cu(II) have been synthesised, and their structures were confirmed by different spectral techniques. The spectral data and density functional theory (DFT) calculations supported the bonding of pefloxacin drug molecule via one of the carboxylate oxygen atoms and the pyridone oxygen atom, and the thiosemicarbazone ligand via the imine nitrogen and the thione sulfur atoms with the metal(II) ion, forming distorted octahedral geometry. In vitro antiproliferative activity of the synthesized complexes was evaluated against three human breast cancer (T47D, estrogen negative (MDA-MB-231) and estrogen positive (MCF-7)) as well as non-tumorigenic human breast epithelial (MCF-10a) cell lines, which showed the higher activity for the copper(II) complexes. The interaction of the synthesized complexes with an oncogenic protein H-ras (121 p) was explored by in silico molecular docking studies. Further, in silico pharmacokinetics and ADMET parameters were also analysed to predict the drug-likeness as well as non-toxic and non-carcinogenic behavior, and safe oral administration of the complexes.     

Effects of copper on algal communities at different current velocities

This study examines the influence of current velocity in the toxiceffect of copper in diatom-dominated biofilms grown in artificial channels.Effects on community structure, algal biomass and photosynthesis (carbonincorporation) caused by 15 g L^–1 of copperwere tested at contrasting (1 and 15 cm s^–1)velocities. Moreover, a possible threshold on the effect of copper on algalbiomass and photosynthesis related to current velocity was examined by usingprogressively increasing current velocity (1 to 50 cms^–1) at 15 g L^–1 Cu.Chlorophyll-a decreased ca. 50% as a result of addition of15 g L^–1 Cu. Chlorophyll decrease occurredearlier at 15 cm s^–1 than at 1 cms^–1 when adding 15 g L^–1Cu. Copper also caused a remarkable decrease in carbon incorporation(from 30 to ca. 50%), which was produced earlier at 15 cms^–1 (three days) than at 1 cms^–1 (seven days). Some taxa were affected by thecombination of copper and current velocity. Both Achnanthesminutissima and Stigeoclonium tenue becomedominant at 15 cm s^–1 in the presence of copper.Significant inhibition of algal growth in 15 g L^–1Cu occurred at low (1 cm s^–1) and highvelocities (50 cm s^–1), but not at intermediatevelocity (20 cm s^–1). The experiments indicatethat current velocity triggers the effect that copper has on diatom-dominatedbiofilms, and that the effect is more remarkable at low and high than atintermediate current velocities.     

Planktonic bacterial biomass and seasonal pattern of the heterotrophic uptake and respiration of glucose and amino acids in the shallow sandpit lake of Créteil (Paris Suburb,France)

Biomass and activity of planktonic bacteria were investigated during a one year study in a shallow sandpit lake. The shallowness of the lake helped keep the water column homogeneous regarding bacterioplankton. Small free-living bacteria (0.03 µm³ cell^–1) dominated the populations throughout the period studied. Bacterial abundances varied from 1 to 11 × 10⁶ cells ml^–1. Kinetic parameters (V _max, K + S and T) were determined with ¹⁴C labelled compounds (glucose and amino acids mixture). V _max values were high and averaged 0.056 and 0.050 µgCl^–1 h^–1 for glucose and amino acids respectively. Maximal V _max values were observed in summer at the highest temperatures, but also in early spring. T values were much greater in winter. K + S values were significantly higher for amino acids (3 µg Cl^–1) than for glucose (1 µg Cl^–1). A low percentage of mineralization (about 25% for both tracers) could be the expression of the high growth efficiency expected when bacteria are growing at the expense of low molecular weight compounds as phytoplankton exudates.     

X-ray crystal structures of the copper(II), nickel(II) and silver(I) complexes of a 17-membered dibenzo macrocycle with a N3S2 donor set

The copper(II), nickel(II) and silver(I) complexes of the pentadentate 17-membered macrocycle 1, 12, 15-triaza-3, 4:9, 10-dibenzo-5,8-dithiacycloheptadecane (L¹) have been prepared as perchlorates and characterized by X-ray crystallography. The N₃S₂ ligand uses all donor atoms for complexation. The copper coordination is square pyramidal with one sulfur atom in the axial site. Ni(II) displays an octahedral coordination by an interaction with a water molecule. The Ag(I) coordination is best described as a distorted pentagonal bipyramid. In [CuL¹]²⁺ the 1, 4, 7-triazaheptane fragment of L¹ is meridionally coordinated, but facially in [NiL¹(H₂O)]²⁺ and intermediate in [AgL¹](ClO₄). Crystal data for [CuL¹](ClO₄)₂: monoclinic, space group P2₁/n, a = 13.153(8), b = 11.951(5), c = 17.880(8)Å, β = 110.29(4)°, Z = 4, R = 0.086 for 2732 independent reflections with I 2σ(I); [NiL¹(H₂O)](ClO₄)₂: monoclinic, P2₁/a, a = 10.771(2), b= 16.157(2), c = 15.286(2) Å, β =93.08(1)°, Z = 4, R = 0.085 for 1464 independent reflections with I 2σ(I); [AgL¹](ClO₄): monoclinic, P2₁/n, a = 12.708(9), b = 9.483(7), c = 19.569(13) Å, β= 103.95(6)°, Z = 4, R = 0.039 for 3600 independent reflections with I 2σ(I).