Characterization of xanthans from selected Xanthomonas strains cultivated under constant dissolved oxygen

Seventeen wild-type Xanthomonas isolates were screened in terms of broth viscosity in shake-flasks. As culture conditions affect polymer characteristics, a fair comparison among isolates required their cultivation in a fermenter under controlled dissolved oxygen tension. Three isolates and a reference strain were studied. The mean molecular weights and molecular weight distributions of their xanthans were determined. Products showed different pyruvate (0.2–7%), acetate (5–10%) and proteinaceous nitrogen (1–3%) contents. The selected isolates exhibit properties which could improve xanthan gum production and some could be used to produce polymers with specific characteristics.     

Effect of hosts and parasite density on the egg parasiteTrichogramma pretiosum [Hym.: Trichogrammatidae]

When females ofTrichogramma pretiosum Riley were confined with host eggs at a density of 2/150 eggs, they produced 12 times more female progeny on eggs of potato tuber moth than on eggs ofHeliothis armigera (Hübner) and 13,6 times more on eggs ofSitotroga cerealella (Olivier) than on eggs ofHeliothis. At a density of 4/150 eggs, the correspondent figures were 13 and 8 times. The percentage emergence fromHeliothis eggs was from 0,29 to 0,14 times as great as from tuber moth orSitotroga. From 15 to 140 times more runts were observed amongTrichogramma fromHeliothis eggs than among those from tuber moth eggs and 8 times more thant among those fromSitotroga eggs. This may explain the low recoveries in South Africa ofT. pretiosum in eggs ofH. armigera collected in cotton fields after mass liberation of the parasite. An increase in parasite density from 1/300 eggs to 16/300 eggs resulted in a decrease from 29 to 14 in the hosts parasitised per female, a decrease in the proportion of female progeny from 72 to 39%, a decrease in the female progeny per female from 18 to 4,8, and an increase in the proportion of runts from 2,4 to 12,4%. It is suggested that in mass culture ofTrichogramma unduly high parasite densities should be avoided in order to reduce the effect of mutual interference and raise the output of female progeny.     

A computational algorithm to simulate disorganization of collagen network in injured articular cartilage

Cartilage defects are a known risk factor for osteoarthritis. Estimation of structural changes in these defects could help us to identify high risk defects and thus to identify patients that are susceptible for the onset and progression of osteoarthritis. Here, we present an algorithm combined with computational modeling to simulate the disorganization of collagen fibril network in injured cartilage. Several potential triggers for collagen disorganization were tested in the algorithm following the assumption that disorganization is dependent on the mechanical stimulus of the tissue. We found that tensile tissue stimulus alone was unable to preserve collagen architecture in intact cartilage as collagen network reoriented throughout the cartilage thickness. However, when collagen reorientation was based on both tensile tissue stimulus and tensile collagen fibril strains or stresses, the collagen network architecture was preserved in intact cartilage. Using the same approach, substantial collagen reorientation was predicted locally near the cartilage defect and particularly at the cartilage–bone interface. The developed algorithm was able to predict similar structural findings reported in the literature that are associated with experimentally observed remodeling in articular cartilage. The proposed algorithm, if further validated, could help to predict structural changes in articular cartilage following post-traumatic injury potentially advancing to impaired cartilage function.     

Luteolin protects against lead acetate-induced nephrotoxicity through antioxidant,anti-inflammatory,anti-apoptotic,and Nrf2/HO-1 signaling pathways

Molecular Biology Reports - Lead (Pb) is one of the most common heavy metal pollutants affecting living organisms. It induces nephrotoxicity with significant alterations in renal structure and...     

Evaluation of the Possible Epileptogenic Activity of Ciprofloxacin: The Role of Nigella sativa on Amino Acids Neurotransmitters

The neuroprotective effect of Nigella sativa (NS) on amino acid neurotransmitters alteration in pentylenetetrazole (PTZ) and ciprofloxacin (CFX) treated rats in different brain regions was examined. The oral administration of NS induced an elevation in aspartate and glutamate contents, whereas the levels of GABA and glycine were decreased. Furthermore, the treated groups with PTZ and CFX caused a decrease in aspartate, glutamate and total antioxidant capacity levels, while the concentrations of GABA and glycine were increased after 14 days. Moreover, the pre- and post-treatment with NS in PTZ and CFX treated rats return the levels of these parameters near control values. So, it could be concluded that the treatment with CFX induced imbalance between the excitatory and the inhibitory amino acids which may lead to the initiation of epileptic seizures and the treatment with NS was found to ameliorate these neurological defects which reflect its potent antiepileptic activity.     

Alleviation of autophagy by knockdown of Beclin-1 enhances susceptibility of hippocampal neurons to proapoptotic signals induced by amino acid starvation

Autophagy has been described as a cellular response to stressful stimuli like starvation. One of its primary functions is to recycle amino acids from degraded proteins for cellular survival under nutrient deprived conditions. Autophagy is characterized by double membrane cytosolic vesicles called autophagosomes and prolonged autophagy is known to result in autophagic (Type II) cell death. Beclin-1 is involved in the regulation of autophagy in mammalian cells. This study examined the potential impact of knockdown of Beclin-1 in an autophagic response in HT22 neurons challenged with amino acid starvation (AAS). AAS exposure induced light chain-3 (LC-3)-immunopositive and monodansylcadaverine (MDC) fluorescent dye-labeled autophagosome formation in cell bodies as early as 3 h post-AAS in wild type cells. Elevated levels of the autophagosome-targeting LC3-II were also observed following AAS. In addition, neuronal death induced by AAS in HT22-cells led to a moderate activation of caspase-3, a slight upregulation of AIF and did not alter the HtrA2 levels. Autophagy inhibition by a knockdown of Beclin-1 significantly reduced AAS-induced LC3-II increase, reduced accumulation of autophagosomes, and potentiated AAS-mediated neuronal death. Collectively, this study shows that the both apoptotic and autophagic machineries are inducible in cultured hippocampal HT22 neurons subjected to AAS. Our data further show that attenuation of autophagy by a knockdown of Beclin-1 enhanced neurons susceptibility to proapoptotic signals induced by AAS and underlines that autophagy is per se a protective than a deleterious mechanism.     

Selection of ceramic fluorapatite‐binding peptides from a phage display combinatorial peptide library: optimum affinity tags for fluorapatite chromatography

Peptide affinity tags have become efficient tools for the purification of recombinant proteins from biological mixtures. The most commonly used ligands in this type of affinity chromatography are immobilized metal ions, proteins, antibodies, and complementary peptides. However, the major bottlenecks of this technique are still related to the ligands, including their low stability, difficulties in immobilization, and leakage into the final products. A model approach is presented here to overcome these bottlenecks by utilizing macroporous ceramic fluorapatite (CFA) as the stationary phase in chromatography and the CFA‐specific short peptides as tags. The CFA chromatographic materials act as both the support matrix and the ligand. Peptides that bind with affinity to CFA were identified from a randomized phage display heptapeptide library. A total of five rounds of phage selection were performed. A common N‐terminal sequence was found in two selected peptides: F4‐2 (KPRSMLH) and F5‐4 (KPRSVSG). The peptide F5‐4, displayed by more than 40% of the phages analyzed in the fifth round of selection, was subjected to further studies. Selectivity of the peptide for the chemical composition and morphology of CFA was assured by the adsorption studies. The dissociation constant, obtained from the F5‐4/CFA adsorption isotherm, was in the micromolar range, and the maximum capacity was 39.4 nmol/mg. The chromatographic behavior of the peptides was characterized on a CFA stationary phase with different buffers. Preferential affinity and specific retention properties suggest the possible application of the phage‐derived peptides as a tag in CFA affinity chromatography for enhancing the selective recovery of proteins. Copyright © 2013 John Wiley & Sons, Ltd.     

Proteome wide evaluation of the separation ability of hydrophobic interaction chromatography by fluorescent dye binding analysis

Hydrophobic interaction chromatography (HIC) is an important tool in the industrial purification of proteins from various sources. The HIC separation behavior of individual (or model) proteins has been widely researched by others. On the contrary, this study focused on the fractionation ability of HIC when it is challenged with whole proteomes. The impact of the nature of three different proteomes, that is, yeast, soybean, and Chinese hamster ovary cells, on HIC separation was investigated. In doing so, chromatography fractions obtained under standardized conditions were evaluated in terms of their overall hydrophobicity—as measured by fluorescence dye binding. This technique allowed for the calculation of an average protein surface hydrophobicity (S₀) for each fraction; a unique correlation between S₀ and the observed chromatographic behavior was established in each case. Following a similar strategy, the effect of three different ligands (polypropylene glycol, phenyl, and butyl) and two adsorbent particle sizes (65 and 100 µm) on the chromatographic behavior of the yeast proteome was evaluated. As expected, the superficial hydrophobicity of the proteins eluted is correlated with the salt concentration of its corresponding elution step. The findings reveled how—and in which extent—the type of ligand and the size of the beads actually influenced the fractionation of the complex biological mixture. Summarizing, the approach presented here can be instrumental to the study of the performance of chromatography adsorbents under conditions close to industrial practice and to the development of downstream processing strategies. Copyright © 2013 John Wiley & Sons, Ltd.     

Comparison if the addition of multilevel vertebral augmentation to conventional therapy will improve the outcome of patients with multiple myeloma

Background

This was a prospective study to evaluate the effect of multilevel vertebral augmentation in addition to conventional therapy in multiple myeloma patients.

Methods

We treated 27 patients, whom were recently diagnosed to have multiple myeloma by two ways of treatment. Thirteen patients (group I) were treated with conventional therapy and 14 patients (group II) with adding vertebroplasty and kyphoplasty. Patients were evaluated pre-treatment and at half, one, two and 3-years post-treatment by using Oswestry Disability Index (ODI), the Stanford Score (SS) and the Spinal Instability Neoplastic Score (SINS).

Results

Mean values of ODI, SS and SINS were 31.9 (63.8%), 4.3 and 13.8 for group I and 33.2 (66.4%), 4.6 and 12.8 for group II before starting treatment. Group II showed improvement better than group I at all follow-up intervals with best results at first 6 months. P-values at the end of the study were ODI?=?0.047, SS?=?0.180 and SINS?=?0.002. Mortality rates were equal of both groups (four patients of each group).

Conclusion

Adding vertebral augmentation to conventional therapy improves multiple myeloma patients’ quality of life, but didn’t affect the mortality rate.