Production and optimization of L-asparaginase by Bacillus sp. KK2S4 from corn cob

L-Asparaginase (L-asparagine amido hydrolase, E.C.3.5.1.1) is an important enzyme which has antitumor properties. This paper describes the production and optimization of L-asparaginase by Bacillus sp. KK2S4 utilization of ground corn cob waste as substrate to reduce and manage the waste in our environment. Thirty-nine (39) bacterial isolates were screened for their L-asparaginase productivity and protein content. Only Bacillus sp. KK2S4 was identified before and selected as the most potent isolate. Modified M9 (MM9) minimal complete medium (glucose free) was used as production media for enzyme production. The highest enzyme production was detected at pH 5.0 in presence of lactose and NaNO3 as the best carbon and nitrogen sources with high activity increasing percentage of 1058.9, 377.3 and 566.7%, respectively.Keywords: L-Asparaginase production, corn cob waste, enzyme optimization, anti-tumor agentAfrican Journal of Biotechnology Vol. 12(19), pp. 2654-265

Thermodynamics of trapped interacting bosons in one dimension

On the basis of Bethe ansatz solution of bosons with delta-function interaction in a one-dimensional potential well, the thermodynamics equilibrium of the system in finite temperature is studied by using the strategy of Yang and Yang. The thermodynamics quantities, such as specific heat etc. are obtained for the cases of strong coupling limit and weak coupling limit respectively.Comment: RevTEX, 7 pages, 0 figur

Surface Morphological and Nanomechanical Properties of PLD-Derived ZnO Thin Films

This study reports the surface roughness and nanomechanical characteristics of ZnO thin films deposited on the various substrates, obtained by means of atomic force microscopy (AFM), nanoindentation and nanoscratch techniques. ZnO thin films are deposited on (a- and c-axis) sapphires and (0001) 6H-SiC substrates by using the pulsed-laser depositions (PLD) system. Continuous stiffness measurements (CSM) technique is used in the nanoindentation tests to determine the hardness and Young’s modulus of ZnO thin films. The importance of the ratio (H/Efilm) of elastic to plastic deformation during nanoindentation of ZnO thin films on their behaviors in contact-induced damage during fabrication of ZnO-based devices is considered. In addition, the friction coefficient of ZnO thin films is also presented here

Food commodity derivatives: a new cause of malnutrition?

Poverty causes malnutrition, but malnutrition also contributes to poverty through increased morbidity, impaired development in children, and reduced capacity for work and productivity in adults. In rich countries food is a relatively small part of household consumption (10–15%). But in poor countries many households (especially those of wage labourers and landless people) use a large share of their income (40% or more) to buy food, so food price rises adversely affect purchasing power by reducing real income. There is compelling evidence that the recently expanded market in food-commodity derivatives has led to large increases in speculative investment, pushing global food prices far higher than predicted by demand-supply effects. This paper is an attempt to analyze the relationship between food commodity derivatives and food prices

Human pluripotent stem cell-based models suggest preadipocyte senescence as a possible cause of metabolic complications of Werner and Bloom Syndromes.

Werner Syndrome (WS) and Bloom Syndrome (BS) are disorders of DNA damage repair caused by biallelic disruption of the WRN or BLM DNA helicases respectively. Both are commonly associated with insulin resistant diabetes, usually accompanied by dyslipidemia and fatty liver, as seen in lipodystrophies. In keeping with this, progressive reduction of subcutaneous adipose tissue is commonly observed. To interrogate the underlying cause of adipose tissue dysfunction in these syndromes, CRISPR/Cas9 genome editing was used to generate human pluripotent stem cell (hPSC) lacking either functional WRN or BLM helicase. No deleterious effects were observed in WRN-/- or BLM-/- embryonic stem cells, however upon their differentiation into adipocyte precursors (AP), premature senescence emerged, impairing later stages of adipogenesis. The resulting adipocytes were also found to be senescent, with increased levels of senescent markers and senescence-associated secretory phenotype (SASP) components. SASP components initiate and reinforce senescence in adjacent cells, which is likely to create a positive feedback loop of cellular senescence within the adipocyte precursor compartment, as demonstrated in normal ageing. Such a scenario could progressively attenuate adipose mass and function, giving rise to "lipodystrophy-like" insulin resistance. Further assessment of pharmacological senolytic strategies are warranted to mitigate this component of Werner and Bloom syndromes

Morphological stability in epitaxially strained films on a substrate with finite thickness

Abstract This paper investigates the morphological stability of epitaxial films growing heteroepitaxially on ultra-thin substrates. The misfitting strain model is incorporated into the quasi-static mechanical equilibrium system. The interfacial evolution equation between the vapour and film phases is used to solve the film evolution. The perturbation method of normal modes is used to derive the analytical form of the normal-mode growth rate. Additionally, this paper investigates the dynamic behaviour of the vapour-film interface. The results of the study show that a decrease in substrate thickness tends to stabilize the system regardless of whether the stiffness ratio, ρ (i.e. the ratio of film stiffness to substrate stiffness) is less than, equal to or greater than unity. Furthermore, it is found that the effects of a finite substrate thickness on the stability behaviour of the system are quite profound, and that this is particularly true when the film thickness is close to h c with values of stiffness ratio greater than unity

Evaluation of human dermal fibroblasts directly reprogrammed to adipocyte-like cells as a metabolic disease model.

Adipose tissue is the primary tissue affected in most single gene forms of severe insulin resistance, and growing evidence has implicated it as a site at which many risk alleles for insulin resistance identified in population-wide studies might exert their effect. There is thus increasing need for human adipocyte models in which to interrogate the function of known and emerging genetic risk variants. However, primary adipocyte cultures, existing immortalised cell lines and stem-cell based models all have significant biological or practical limitations. In an attempt to widen the repertoire of human cell models in which to study adipocyte-autonomous effects of relevant human genetic variants, we have undertaken direct reprogramming of skin fibroblasts to adipocyte-like cells by employing an inducible recombinant lentivirus overexpressing the master adipogenic transcription factor PPARγ2. Doxycycline-driven expression of PPARγ2 and adipogenic culture conditions converted dermal fibroblasts into triglyceride-laden cells within days. The resulting cells recapitulated most of the crucial aspects of adipocyte biology in vivo, including the expression of mature adipocyte markers, secreted high levels of the adipokine adiponectin, and underwent lipolysis when treated with isoproterenol/3-isobutyl-1-methylxanthine (IBMX). They did not, however, exhibit insulin-inducible glucose uptake, and withdrawal of doxycycline produced rapid delipidation and loss of adipogenic markers. This protocol was applied successfully to a panel of skin cells from individuals with monogenic severe insulin resistance; however, surprisingly, even cell lines harbouring mutations causing severe, generalised lipodystrophy accumulated large lipid droplets and induced adipocyte-specific genes. The direct reprogramming protocol of human dermal fibroblasts to adipocyte-like cells we established is simple, fast and efficient, and has the potential to generate cells which can serve as a tool to address some, though not all, aspects of adipocyte function in the presence of endogenous disease-causing mutations

A New Method to Search for High-redshift Clusters Using Photometric Redshifts

We describe a new method (Poisson probability method, PPM) to search for high-redshift galaxy clusters and groups by using photometric redshift information and galaxy number counts. The method relies on Poisson statistics and is primarily introduced to search for megaparsec-scale environments around a specific beacon. The PPM is tailored to both the properties of the FR I radio galaxies in the Chiaberge et al. sample, which are selected within the COSMOS survey, and to the specific data set used. We test the efficiency of our method of searching for cluster candidates against simulations. Two different approaches are adopted. (1) We use two z ~ 1 X-ray detected cluster candidates found in the COSMOS survey and we shift them to higher redshift up to z = 2. We find that the PPM detects the cluster candidates up to z = 1.5, and it correctly estimates both the redshift and size of the two clusters. (2) We simulate spherically symmetric clusters of different size and richness, and we locate them at different redshifts (i.e., z = 1.0, 1.5, and 2.0) in the COSMOS field. We find that the PPM detects the simulated clusters within the considered redshift range with a statistical 1\u3c3 redshift accuracy of ~0.05. The PPM is an efficient alternative method for high-redshift cluster searches that may also be applied to both present and future wide field surveys such as SDSS Stripe 82, LSST, and Euclid. Accurate photometric redshifts and a survey depth similar or better than that of COSMOS (e.g., I < 25) are required

Body mass index and risk of pancreatic cancer in a Chinese population

10.1371/journal.pone.0085149PLoS ONE91-POLN

Cluster Candidates around Low-power Radio Galaxies at z ~ 1-2 in COSMOS

We search for high-redshift (z ~1-2) galaxy clusters using low power radio galaxies (FR I) as beacons and our newly developed Poisson probability method based on photometric redshift information and galaxy number counts. We use a sample of 32 FR Is within the Cosmic Evolution Survey (COSMOS) field from the Chiaberge et al. catalog. We derive a reliable subsample of 21 bona fide low luminosity radio galaxies (LLRGs) and a subsample of 11 high luminosity radio galaxies (HLRGs), on the basis of photometric redshift information and NRAO VLA Sky Survey radio fluxes. The LLRGs are selected to have 1.4 GHz rest frame luminosities lower than the fiducial FR I/FR II divide. This also allows us to estimate the comoving space density of sources with L 1.4 ~= 1032.3 erg s-1 Hz-1 at z ~= 1.1, which strengthens the case for a strong cosmological evolution of these sources. In the fields of the LLRGs and HLRGs we find evidence that 14 and 8 of them reside in rich groups or galaxy clusters, respectively. Thus, overdensities are found around ~70% of the FR Is, independently of the considered subsample. This rate is in agreement with the fraction found for low redshift FR Is and it is significantly higher than that for FR IIs at all redshifts. Although our method is primarily introduced for the COSMOS survey, it may be applied to both present and future wide field surveys such as Sloan Digital Sky Survey Stripe 82, LSST, and Euclid. Furthermore, cluster candidates found with our method are excellent targets for next generation space telescopes such as James Webb Space Telescope