Studying the cytotoxicity and oxidative stress induced by two kinds of bentonite particles on human B lymphoblast cells in vitro

The aim of the present study was to evaluate the cytotoxicity and oxidative stress induced by native and active bentonite particles (BPs) on human B lymphoblast cells using seven assays. Our results showed that the order of cytotoxicity was: active BPs > native BPs > quartz particles (DQ-12) > gypsum, according to the IC50 values in CCK-8 assay and neutral red uptake (NRU) assay. The lactate dehydrogenase (LDH) leakage, the proportions of early apoptotic cells, the reactive oxygen species (ROS) generation, the superoxide dismutase (SOD) inhibition and the malondialdehyde (MDA) release in the native and active BPs groups were significantly higher than those in the gypsum and DQ-12 groups (P < 0.05 or P < 0.01). Moreover, the cytotoxicity of active BPs with higher adsorption capacity of phenol was higher than that of native BPs with relatively lower adsorption capacity of phenol. The oxidative stress induced by active BPs was significantly higher than that induced by native BPs (P < 0.05 or P < 0.01). The water-soluble fractions of BPs did not induce the cytotoxicity and ROS generation. These findings indicated that active and native BPs could induce significantly the cytotoxic effects and oxidative stress on human B lymphoblast cells in vitro. The cytotoxic difference between active BPs and native BPs may be associated with the adsorption capacity of BPs and oxidative stress induced by BPs to a certain extent. The insoluble particle fractions may play a main role in the cytotoxic effects and oxidative stress induced by BPs.     

Class II α-mannosidase from Aspergillus fischeri: Energetics of catalysis and inhibition

Energetics of the catalysis of Class II α-mannosidase (E.C.3.2.1.24) from Aspergillus fischeri was studied. The enzyme showed K_cat/K_m for Man (α1-3) Man, Man (α1-2) Man and Man (α1-6) Man as 7488, 5376 and 3690 M^?1 min^?1, respectively. The activation energy, E_a was 15.14, 47.43 and 71.21 kJ/mol for α1-3, α1-2 and α1-6 linked mannobioses, respectively, reflecting the energy barrier in the hydrolysis of latter two substrates. The enzyme showed K_cat/K_m as 3.56 × 10⁵ and 4.61 × 10⁵ M^?1 min^?1 and E_a as 38.7 and 8.92 kJ/mol, towards pNPαMan and 4-MeUmbαMan, respectively. Binding of Swainsonine to the enzyme is stronger than that of 1-deoxymannojirimycin.     

Association of TP53 codon 72 and CDH1 genetic polymorphisms with colorectal cancer risk in Bangladeshi population

Till now no pharmacogenetic study of TP53 codon 72 (Arg72Pro) and CDH1 rs16260 (-160C<A) genes has been reported on Bangladeshi population relating those with colorectal cancer. So the aim of the study is to determine whether there is an elevated risk of colorectal cancer development with TP53 codon 72 and CDH1 rs16260 genetic polymorphism in Bangladeshi population for the first time. To investigate the association of these two SNPs, we conducted a case-control study with 288 colorectal cancer patients and 295 healthy volunteers by using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method. We found an increased risk of association between Arg/Pro heterozygosity (adjusted OR = 2.58, 95% CI = 1.77–3.77, p < 0.05) and Pro/Pro mutant homozygosity (adjusted OR = 2.92, 95% CI = 1.78–4.78, p < 0.05) along with the combined genotype (Arg/Pro + Pro/Pro) (adjusted OR = 2.70, 95% CI = 1.90–3.82, p < 0.05) and colorectal cancer predisposition. In case of CDH1 rs16260 polymorphism, C/A heterozygous and A/A mutant homozygous are significantly (p < 0.05) found to be associated with colorectal cancer risk with adjusted OR of 1.94 and 2.63, respectively. The combined genotype of C/A and A/A was also found to be strongly associated with colorectal cancer risk compared to C/C genotype (adjusted OR = 2.02, 95% CI = 1.42–2.87, p < 0.05). In conclusion, heterozygosity and mutant homozygosity as well as the combination of both TP53 Arg72Pro and CDH1 rs16260 polymorphisms are responsible to increase the risk of colorectal cancer development in Bangladeshi population.     

Stabilization of Escherichia coli uridine phosphorylase by evolution and immobilization

Mutation and immobilization techniques were applied to uridine phosphorylase (UP) from Escherichia coli in order to enhance its thermal stability and hence productivity in a biocatalytic reaction. UP was evolved by iterative saturation mutagenesis. Compared to the wild type enzyme, which had a temperature optimum of 40 °C and a half-life of 9.89 h at 60 °C, the selected mutant had a temperature optimum of 60 °C and a half-life of 17.3 h at 60 °C. Self-immobilization of the native UP as a Spherezyme showed a 3.3 fold increase in thermostability while immobilized mutant enzyme showed a 4.4 fold increase in thermostability when compared to native UP. Combining UP with the purine nucleoside phosphorylase from Bacillus halodurans allows for synthesis of 5-methyluridine (a pharmaceutical intermediate) from guanosine and thymine in a one-pot transglycosylation reaction. Replacing the wild type UP with the mutant allowed for an increase in reaction temperature to 65 °C and increased the reaction productivity from 10 to 31 g l⁻¹ h⁻¹.     

Effects of selenium compounds on proliferation and epigenetic marks of breast cancer cells

Breast cancer is a global public health problem and the most frequent cause of cancer death among women. Mammary carcinogenesis is driven not only by genetic alterations but also by epigenetic disturbances. Because epigenetic marks are potentially reversible they represent promising molecular targets for breast cancer prevention interventions. Selenium is a promising anti-breast cancer trace element that has shown the modulation of DNA methylation and histone post-translational modifications in other malignancies. This study aimed to evaluate the effects of selenium compounds [methylseleninic acid (MSA) and selenite] on cell proliferation and death, expression of the tumor suppressor gene RASSF1A and epigenetic marks in MCF-7 human breast adenocarcinoma cells. Treatment with MSA or selenite markedly inhibited (P < 0.05) in a dose-dependent manner the proliferation of MCF-7 cells. MSA induced (P < 0.05) G2/M cell arrest while selenite presented the opposite effect. Regarding cell death induction, MSA acted mainly by inducing apoptosis (P < 0.05), while selenite only induced necrosis (P < 0.05). Furthermore selenite, but not MSA, markedly induced (P < 0.05) cytotoxicity and increased (P < 0.05) RASSF1A expression. Both selenium compounds inhibited (P < 0.05) DNMT1 expression. MSA decreased (P < 0.05) H3K9me3 and increased (P < 0.05) H4K16ac, while selenite decreased (P < 0.05) this latter histone mark. To the best of our knowledge this is the first report showing that selenite and MSA modulate epigenetic marks specifically in breast cancer cells. Our data reinforce the anti-breast cancer potential of selenium that is dependent on its chemical form. Furthermore the data show that epigenetic mechanisms represent relevant molecular targets involved in selenium inhibitory effects in breast cancer cells.     

Apolipoprotein A-I inhibits chemotaxis,adhesion, activation of THP-1 cells and improves the plasma HDL inflammatory index

The anti-inflammatory effects of high density lipoprotein (HDL) are well described, however, such effects of Apolipoprotein A-I (ApoA-I) are less studied. Building on our previous study, we further explored the mechanism of anti-inflammatory effects of ApoA-I, and focused especially on the interaction between monocyte and endothelial cells and plasma HDL inflammatory index in LPS-challenged rabbits. Our results show that ApoA-I significantly decreased LPS-induced MCP-1 release from THP-1 cells and ox-LDL-induced THP-1 migration ratio (P < 0.01, respectively). ApoA-I significantly decreased sL-selectin, sICAM-1 and sVCAM-1 release (P < 0.01, P < 0.01, P < 0.05, respectively) from LPS-stimulated THP-1 cells. Furthermore, ApoA-I significantly inhibited LPS-induced CD11b and VCAM-1 expression on THP-1 cells (P < 0.01, P < 0.05, respectively). ApoA-I diminished LPS-induced mCD14 expression (P < 0.01) and NFκB nuclear translocation in THP-1 cells. After single dose treatment of ApoA-I, the value of plasma HDL inflammatory index in LPS-challenged rabbits was improved significantly (P < 0.05). These results suggest that ApoA-I can inhibit chemotaxis, adhesion and activation of human monocytes and improve plasma HDL inflammatory index with presenting beneficial anti-inflammatory effects.     

Testing genotoxicity and cytotoxicity strategies for the evaluation of commercial radiosterilized fetal calf sera

Effects of 18 commercial lots of fetal calf serum (FCS) after γ-irradiation and their non-irradiated counterparts were comparatively analyzed on CHO-K1 and MDBK MDL1 cells for genotoxicity [sister chromatid exchange (SCE), micronuclei (MNi), and single cell gel electrophoresis (SCGE)], cytotoxicity [cell-cycle progression (CCP), proliferative replication index (PRI), mitotic index (MI), growth promotion (GP), and plating efficiency (PE)], and microbiological properties (mycoplasma and bovine viral diarrhea virus contamination). SCE and SCGE were the most informative end-points for genotoxicity since significant differences were found in 44.4% (P < 0.05–0.001, Student's t-test) and 61.1% (P < 0.05–0.001, χ² test) samples, respectively. MI was the cytotoxicity assay revealing the greatest variation, showing differences in 66.7% (P < 0.05–0.001, χ² test) samples. Thus, these three end-points for screening bioproducts such as FCS were found most suitable for detecting potential geno-cytotoxicants in biological samples; their simultaneous use could be strongly recommended.     

The effect of pH,bile and calcium on the adhesion ability of probiotic enterococci of animal origin to the porcine jejunal epithelial cell line IPEC-J2

Examination of adhesion ability using a quantitative assay based on radiolabelled bacteria showed that 10 Enterococcus strains exhibited adhesion ability from 2 to 4%. Enterococcus faecium EF2019 (isolate from rabbit faeces, deponed to Czech Culture of Microorganisms in Brno, CCM 7420) showed the highest adhesion ability (4.0 ± 0.4%). With regard to survival, all strains displayed good resistance towards 0.3% oxgall and HCl (pH 3.0). Pretreatment of strains with HCl (pH 3.0) significantly reduced their adhesion. Pretreatment of strains by oxgall significantly reduced the adhesion capacity of E. faecium EF2019, EF1839 and EF319 strains, while the adhesion ability of E. faecium EE3 (isolate from canine feed) slightly increased. Furthermore, addition of calcium (200 mmol/l) significantly increased (P < 0.001) the adhesion ability for all strains tested. The adhesion ability of the isolates from rabbits, EF1839 and EF529, as well as the isolate EE3 (strain from canine feed) increased from 2–3% up to 50–55% upon calcium addition. Despite, in general low adhesive properties, strains can survive passage through the gastrointestinal tract.     

Deletion of psbJ leads to accumulation of Psb27–Psb28 photosystem II complexes in Thermosynechococcus elongatus

The life cycle of Photosystem II (PSII) is embedded in a network of proteins that guides the complex through biogenesis, damage and repair. Some of these proteins, such as Psb27 and Psb28, are involved in cofactor assembly for which they are only transiently bound to the preassembled complex. In this work we isolated and analyzed PSII from a ΔpsbJ mutant of the thermophilic cyanobacterium Thermosynechococcus elongatus. From the four different PSII complexes that could be separated the most prominent one revealed a monomeric Psb27–Psb28 PSII complex with greatly diminished oxygen-evolving activity. The MALDI-ToF mass spectrometry analysis of intact low molecular weight subunits (< 10 kDa) depicted wild type PSII with the absence of PsbJ. Relative quantification of the PsbA1/PsbA3 ratio by LC-ESI mass spectrometry using ¹⁵N labeled PsbA3-specific peptides indicated the complete replacement of PsbA1 by the stress copy PsbA3 in the mutant, even under standard growth conditions (50 μmol photons m^? 2 s^? 1). This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.     

O2 reduction by photosystem I involves phylloquinone under steady-state illumination

O₂ reduction was investigated in photosystem I (PS I) complexes isolated from cyanobacteria Synechocystis sp. PCC 6803 wild type (WT) and menB mutant strain, which is unable to synthesize phylloquinone and contains plastoquinone at the quinone-binding site A₁. PS I complexes from WT and menB mutant exhibited different dependencies of O₂ reduction on light intensity, namely, the values of O₂ reduction rate in WT did not reach saturation at high intensities, in contrast to the values in menB mutant. The obtained results suggest the immediate phylloquinone involvement in the light-induced O₂ reduction by PS I.     

Two new rotenoids from the roots of Millettia speciosa

Two new rotenoids, named millettiaosas A–B (1–2), together with four known compounds were isolated from the roots of Millettia speciosa. Their structures were elucidated on the basis of spectroscopic analysis including 1D and 2D NMR techniques and HRESIMS. Evaluation of the two new compounds for cytotoxicity against four human cancer cell lines (MCF-7, HCT-116, A549 and HepG-2) showed moderate activities (10 μM < IC₅₀ < 26 μM).     

Esculentin-2CHa: A host-defense peptide with differential cytotoxicity against bacteria,erythrocytes and tumor cells

The host-defense peptide, esculentin-2CHa (GFSSIFRGVA¹⁰KFASKGLGK D²⁰LAKLGVDLVA³⁰ CKISKQC) shows potent (MIC ≤ 6 μM) growth inhibitory activity against clinical isolates of multidrug-resistant strains of Staphylococcus aureus, Acinetobacter baumannii, and Stenotrophomonas maltophilia and differential cytotoxic activity against human erythrocytes (LC₅₀ = 150 μM) and human non-small cell lung adenocarcinoma A549 cells (LC₅₀ = 10 μM). Esculentin-2CHa significantly (P < 0.01) stimulates the release of the anti-inflammatory cytokine IL-10 by mouse lymphoid cells and elevates its production after stimulation with concanavalin A and significantly (P < 0.05) stimulates TNF-α production by peritoneal macrophages. Effects on IL-6 and IL-1β production were not significant. Removal of the hydrophobic N-terminal hexapeptide (GFSSIF) from esculentin-2CHa results in abolition of growth inhibitory activity against S. aureus and cytotoxic activity against erythrocytes and A549 cells as well as a marked (≥16-fold) reduction in potency against A. baumannii and S. maltophilia. The primary structure of esculentin-2 has been poorly conserved between frog species but evolutionary pressure has acted to maintain the hydrophobic character of this N-terminal hexapeptide sequence. Removal of the cyclic C-terminal domain (CKISKQC) and replacement of the Cys³¹ and Cys³⁷ residues by serine resulted in appreciable decreases in cytotoxicity against all microorganisms and against mammalian cells. The more cationic [D20K, D27K] analog showed a modest increase in potency against all microorganisms (up to 4-fold) but a marked increase in cytotoxicity against erythrocytes (LC₅₀ = 11 μM) and A549 cells (LC₅₀ = 3 μM).     

Design,synthesis and biological evaluation of new 5-nitro benzimidazole derivatives as AT1 antagonists with anti-hypertension activities

The design, synthesis, in vitro and in vivo evaluation of 5-nitro benzimidazole with 1,4-disubsituted or 1,5-disubsituted indole derivatives as novel angiotensin II receptor antagonist is outlined. Radioligand binding assays showed that 2-(4-((2-butyl-5-nitro-1H-benzo[d]imidazol-1-yl)methyl)-1H-indol-1-yl)benzoic acid, compound 3, displayed a high affinity for the angiotensin II type 1 receptor with IC₅₀ value of 1.03 ± 0.26 nM. The biological evaluation on spontaneously hypertensive rats and renal hypertensive rats showed that 3 could cause significant decrease on MBP in a dose dependent manner, whose maximal response lowered 30 mmHg of MBP at 5 mg/kg and 41 mmHg of MBP at 10 mg/kg after oral administration, and the significant antihypertensive effect lasted beyond 24 h, which is better than Losartan. Taken together 3 could be considered as an effective and durable anti-hypertension drug candidate. These encouraging results are deserved of further investigation towards its use for therapeutic benefit.     

A new strategy for strain improvement of Aurantiochytrium sp. based on heavy-ions mutagenesis and synergistic effects of cold stress and inhibitors of enoyl-ACP reductase

Developing a strain with high docosahexaenoic acid (DHA) yield and stable fermenting-performance is an imperative way to improve DHA production using Aurantiochytrium sp., a microorganism with two fatty acid synthesis pathways: polyketide synthase (PKS) pathway and Type I fatty acid synthase (FAS) pathway. This study investigated the growth and metabolism response of Aurantiochytrium sp. CGMCC 6208 to two inhibitors of enoyl-ACP reductase of Type II FAS pathway (isoniazid and triclosan), and proposed a method of screening high DHA yield Aurantiochytrium sp. strains with heavy ion mutagenesis and pre-selection by synergistic usage of cold stress (4 °C) and FAS inhibitors (triclosan and isoniazid). Results showed that (1) isoniazid and triclosan have positive effects on improving DHA level of cells; (2) mutants from irradiation dosage of 120 Gy yielded more DHA compared with cells from 40 Gy, 80 Gy treatment and wild type; (3) DHA contents of mutants pre-selected by inhibitors of enoyl-ACP reductase of Type II FAS pathway (isoniazid and triclosan)at 4 °C, were significantly higher than that of wild type; (4) compared to the wild type, the DHA productivity and yield of a mutant (T-99) obtained from Aurantiochytrium sp. CGMCC 6208 by the proposed method increased by 50% from 0.18 to 0.27 g/Lh and 30% from 21 to 27 g/L, respectively. In conclusion, this study developed a feasible method to screen Aurantiochytrium sp. with high DHA yield by a combination of heavy-ion mutagenesis and mutant-preselection by FAS inhibitors and cold stress.     

High-level production of erythritol by mutants of osmophilic Moniliella sp.

An erythritol-producing osmophilic yeast-like fungus, Moniliella sp. 440, was isolated from honey and then successively mutated with iterative rounds of N-methyl-N′-nitro-N-nitrosoguanidine (NTG) treatment and selection. Six generations of mutants, named N12115-6, N21105-6, N31074-3, N42208-2, N53199-9, and N61188-12, were selected for and produced erythritol at 151.0, 157.2, 177.8, 191.4, 196.6, and 237.8 g/L, respectively, while the wild type strain produced 113.0 g/L erythritol in media containing 40% glucose and 1% yeast extract. The mutant cells were found to have a short rod-like shape, while the wild type cells have a long rod-like shape. The most efficient erythritol producer, N61188-12, assimilated myo-inositol and weakly assimilated erythritol. However, the wild type strain did not assimilate myo-inositol and assimilated erythritol well. In 250-L and 2000-L pilot-scale fermentors, the erythritol production by N61188-12 was 151.4 g/L and 152.4 g/L, respectively. A simple fed-batch culture of strain N61188-12 in a 2000-L fermentor increased erythritol production to 189.4 g/L after 10 days fermentation.     

Effect of thermal stress on HSP70 expression in dermal fibroblast of zebu (Tharparkar) and crossbred (Karan-Fries) cattle

The present studies were conducted to investigate the difference response of dermal fibroblasts to heat stress in Tharparkar and Karan-Fries cattle. Skin is the most important environmental interface providing a protective envelope to animals. In skin, dermal fibroblasts are the most regular cell constituent of dermis that is crucial for temperature homeostasis. The study aimed to examine the reactive oxygen species (ROS) formation, cytotoxicity (%) and heat shock protein 70 (HSP70) genes expression in dermal fibroblast of Tharparkar and Karan-Fries cattle and to assess whether resistance of dermal fibroblast to heat stress is breed specific. Dermal fibroblasts from ear pinna of Tharparkar and Karan-Fries cattle were exposed at 25 °C, 37 °C, 40 °C and 44 °C for 3 h to measure the ROS, cytotoxicity (%) and HSP 70 (HSPA1A, HSPA2 and HSPA8) genes’ expression. The results showed that ROS formation at low temperature (25 °C) decreased in both breeds as compared to control (37 °C) and the differences were significant (P<0.0001). Heat stress at 40 °C did not increase ROS formation significantly in Tharparkar but increased significantly (P<0.001) in Karan-Fries cattle. The overall cytotoxicity (%) was also found to be significantly different (P<0.001) between Tharparkar and Karan-Fries cattle, and on exposure to different temperatures (P<0.001). The cytotoxicity (%) in dermal fibroblast cells of Karan-fries cows was more than Tharparkar. The expression studies indicated that all HSP70 genes (HSPA8, HSPA1A and HSPA2) were up-regulated at different temperatures in both breeds. In Tharparkar, the relative mRNA expression of HSPA8 gene was higher but HSPA1A and HSPA2 genes were low as compared to Karan-Fries cattle. At 40 and 44 °C, the relative expressions of inducible HSP 70 genes (HSPA1A and HSPA2) were higher in Karan-Fries than Tharparkar. In summary, dermal fibroblast resistance to heat shock differed between breeds. Dermal fibroblasts of Tharparkar were observed to be more heat tolerant than crossbred Karan-Fries cattle. The study concludes that zebu cattle (Tharparkar) dermal fibroblasts are more adapted to tropical climatic condition than crossbreed cattle (Karan-Fries). Differences exist in dermal fibroblasts of heat adapted and non-adapted cattle.     

Field-to-laboratory transport protocol impacts subsequent physiological biomarker response in the marine mussel,Perna canaliculus

The transfer of mussels from field to laboratory, or transplantation between clean and contaminated field settings, is a common protocol in ecotoxicology. However, collection and transport of mussels could lead to stress that may impact biomarker responses, and thus confound interpretation of results. Physiological responses (clearance rate, absorption efficiency, excretion rate, respiration rate and scope-for-growth) of green-lipped mussels (Perna canaliculus) exposed to four different transportation protocols were investigated. These protocols included immersion in site seawater (SSW), immersion in artificial seawater (ASW), and emersion (aerial transport; EMS) at two temperatures (15 °C and 5 °C). Physiological measurements were conducted after a simulated 24 h “transport” phase and a 48 h “recovery” phase. Clearance rates were significantly inhibited by the EMS 5 °C and ASW protocols relative to SSW treatment, although the clearance rate of the latter recovered after 48 h. A similar pattern was observed for excretion and respiration rates for ASW. Decreased excretion rates for EMS 15 °C and respiration rates for EMS 5 °C were also recorded relative to values for SSW following “recovery”. Negative scope-for-growth was observed for all treatments except EMS 15 °C. These data suggest transport emersed at ambient air temperatures is the best method to maintain physiological health of green-lipped mussels.     

Retinopathy is a Strong Determinant of Atherosclerosis in Type 2 Diabetes: Correlation with Carotid Intima Media Thickness

ObjectiveWe investigated the correlation between the severity of diabetic retinopathy (DR) and carotid intima media thickness (IMT) as a marker of atherosclerosis in patients with type 2 diabetes.MethodsThe study group consisted of 140 normo-tensive Egyptian patients (68 males and 72 females) with type 2 diabetes and DR. Carotid IMT was evaluated using high-resolution B-mode ultrasonography. DR was assessed and graded using colored fundus photography and fundus fluorescein angiography, as either nonproliferative DR (NPDR) or proliferative DR (PDR).ResultsCarotid IMT was greater in patients with PDR compared to those with NPDR (1.094 ± 0.142 mm vs. 0.842 ± 0.134 mm; P < .001). Carotid IMT showed positive correlation with diabetes duration (P < .01), systolic blood pressure (P < .001), diastolic blood pressure (P < .01), fasting blood glucose (P < .01), postprandial blood glucose (PPBG) (P < .001), glycated hemoglobin (P < .01), total cholesterol (P < .01), triglycerides (TGs) (P < .001), and DR (P < .0001). No significant difference was found between males and females in any of the studied parameters. Multiple regression analysis revealed that the determinants of carotid IMT in the studied group were age (P < .01), PPBG (P < .01), TGs (P < .001), and DR (P < .0001).ConclusionOur study proves that both NPDR and PDR are strong determinants of carotid IMT and atherosclerosis in patients with type 2 diabetes. (Endocr Pract. 2015;21:226-230)     

Evaluation of distant carbon sources in biosurfactant production by a gamma ray-induced Pseudomonas putida mutant

Pseudomonas putida 33 wild strain, subjected to gamma ray mutagenesis and designated as P. putida 300-B mutant was used as microbial rhamnolipid-producer by using distant carbon sources (viz. hydrocarbons, waste frying oils ‘WFOs’, vegetable oil refinery wastes and molasses) in the minimal media under shake flask conditions. The behavior of glucose as co-substrate and growth initiator was examined. The 300-B mutant strain showed its ability to grow on all the substrates tested and produced rhamnolipid surfactants to different extents however; soybean and corn WFOs were observed to be preferred carbon sources followed by kerosene and paraffin oils, respectively. The best cell biomass (3.5 g l⁻¹) and rhamnolipids yield (4.1 g l⁻¹) were obtained with soybean WFO as carbon source and glucose as growth initiator under fed-batch cultivation showing an optimum specific growth rate (μ) of 0.272 h⁻¹, specific product yield (q_p) of 0.318 g g⁻¹ h and volumetric productivity (P_V) of 0.024 g l⁻¹ h. The critical micelle concentration of its culture supernatant was observed to be 91 mg rhamnolipids l⁻¹ and surface tension as 31.2 mN m⁻¹.     

Growth performance and carcass traits of forage-fed hair sheep wethers

The objective of the present study was to compare live animal performance and carcass characteristics of 3/4 or 7/8 Dorper (DO; n = 30), purebred Katahdin (KA; n = 20), purebred St. Croix (SC; n = 17) and purebred Suffolk (SU; n = 10) lambs born in the spring and fall of 2001. After weaning, lambs were supplemented with up to 680 g of a corn-soybean meal supplement while grazing bermudagrass pastures overseeded with ryegrass. Lambs were slaughtered at approximately 210 d of age. From birth to weaning, DO lambs gained faster (P < 0.001) than KA or SC lambs, whereas KA lambs had higher (P < 0.001) ADG than SC lambs. Additionally, DO and SU wethers had greater (P < 0.02) ADG from weaning to slaughter than SC or KA wethers. Suffolk lambs were heavier (P < 0.001) at slaughter and produced heavier (P < 0.001) carcasses than lambs from hair-sheep breeds. Carcasses of KA lambs were fatter (actual fat thickness; P < 0.02) resulting in higher yield grades (P < 0.03) than carcasses of DO, SC, or SU lambs. Carcasses of DO and SU had larger (P < 0.001) longissimus muscle (LM) areas than those of KA or SC carcasses, whereas kidney fat weight and percentage were greater (P < 0.001) in carcasses from KA and SC than DO and SU lambs. Lean maturity was similar (P = 0.32) among breed-types. However, skeletal maturity was greater (P < 0.001) in SU than hair-sheep carcasses. Flank-streaking scores were similar (P = 0.19) among the breed-types, but conformation scores were higher (P < 0.001) for DO and SU carcasses and resulted in higher (P < 0.001) quality grades than SC carcasses. The LM of SU lambs was lighter (higher L^* values; P < 0.05) than that of KA and SC lambs, whereas the LM from DO lambs was redder (higher a^* values; P < 0.001) than SC and SU and more (P < 0.001) yellow than that of the other breed-types. Chops from SU lambs were tougher (higher shear force values; P < 0.007) than chops from the hair-sheep breeds. Results of this study indicate that ADG, carcass muscularity and meat quality were similar between DO and SU lambs, and, although fatter, carcass muscularity of KA was similar to that of DO lambs.