Optimizing harvest of corn stover fractions based on overall sugar yields following ammonia fiber expansion pretreatment and enzymatic hydrolysis

Background  

Corn stover composition changes considerably throughout the growing season and also varies between the various fractions of the plant. These differences can impact optimal pretreatment conditions, enzymatic digestibility and maximum achievable sugar yields in the process of converting lignocellulosics to ethanol. The goal of this project was to determine which combination of corn stover fractions provides the most benefit to the biorefinery in terms of sugar yields and to determine the preferential order in which fractions should be harvested. Ammonia fiber expansion (AFEX) pretreatment, followed by enzymatic hydrolysis, was performed on early and late harvest corn stover fractions (stem, leaf, husk and cob). Sugar yields were used to optimize scenarios for the selective harvest of corn stover assuming 70% or 30% collection of the total available stover.     

Involvement of the Reck tumor suppressor protein in maternal and embryonic vascular remodeling in mice

Background

The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood.

Results

We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region.

Conclusion

We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution.     

Impact of UV-B Radiation on Thylakoid Membrane and Fatty Acid Profile of <Emphasis Type="Italic">Spirulina platensis</Emphasis>

Ultraviolet-B (UV-B) radiation to thylakoid membrane and fatty acid profile has been investigated in cyanobacterium, Spirulina platensis. The thylakoid membrane was isolated by mechanical disruption of the freeze-dried and lysozyme-treated cells followed by differential density gradient centrifugation and morphological variations were examined. UV radiation distorted the membrane on the outer side with reduced chlorophyll a (chl a) content compared to its untreated counterpart. Liquid chromatography-mass spectrometry (LC-MS) was used for characterization of chl a of the thylakoid membrane. UV-B exposure resulted in alterations in the pigment-protein complexes 47 kDa and 43 kDa. Furthermore, 94 kDa and 20 kDa protein appeared in UV-B-exposed thylakoid membrane of S. platensis. The composition of fatty acid in response to UV-B radiation was detected by gas chromatography–mass spectrometry having 23.5% saturated fatty acid (SFA), 76.4% monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA). In contrast to its UV-B-untreated counterpart, SFA was 46.6%, and MUFA and PUFA were 53.3%. Our findings suggest that UV-B radiation not only affects membrane morphology and its protein profile but also reduces saturated fatty acid and increases unsaturated fatty acids in S. platensis.     

Synthesis,characterization and thermoluminescence studies of (ZnS)1‐x(MnTe)x nanophosphors

The present paper reports the thermoluminescence (TL) of (ZnS)_1‐x(MnTe)_x nanophosphors that were prepared by a wet chemical synthesis method. The structure investigated by X‐ray diffraction patterns confirms the formation of a sphalerite phase whose space group was found to be F 3m. From XRD, TEM and SEM analyses the average sizes of the particles were found to be 12 nm, 11 nm and 15 nm, respectively. Initially the TL intensity increased with increasing values of x because the number of luminescence centres increased; however, for higher values of x the TL intensity decreased because of the concentration quenching. Thus the TL, mechanoluminescence and photoluminescence intensities are optimum for a particular value of x, that is for x = 0.05. Thermoluminescence of the (ZnS)_1‐x (MnTe)_x nanophosphor has not been reported previously. There were two peaks seen in the thermoluminescence glow curves in which the first peak lay at 105–100 °C and the second peak lay at 183.5–178.5 °C. The activation energies for the first and second peaks were found to be 0.45 eV and 0.75 eV, respectively.     

Demonstration of an altered phenylalanyl-tRNA synthetase in an analogue-resistant mutant of Aspergillus nidulans

Summary We have isolated and characterized a new class of p-fluorophenylalanine (FPA)-resistant mutant in Aspergillus nidulans using a phenA strain as the wild type, by optimizing the conditions of growth. All four spontaneous mutants selected on a medium containing FPA were found to be recessive to their wild-type alleles in heterozygous diploids. Complementation analyses and linkage data showed that they were allelic and mapped at a single locus (fpaU) in the facA-riboD interval on the right arm of linkage group V. Partial purification and characterization of Phe-tRNA synthetase from wild-type and mutant strains revealed that the mutant enzyme had a greatly reduced ability to activate the analogue. It is suggested that mutation in the fpaU gene brings about a structural alteration in Phe-tRNA synthetase.Abbreviations FPA DL-p-fluorophenylalanine - phenA auxotroph of phenylalanine - Phe-tRNA synthetase phenylalanyl-transfer ribonucleic acid synthetase Current address: Department of Biological Sciences (M/C 066) The University of Illinois at Chicago, Box 4348, Chicago, IL 60680, USA     

Effectiveness of selection methods in chickpea Cicer arietinum under different environments

Summary Three selection procedures, single-seed-descent, selection of the best 5% in both seed size and seed yield per plant were followed in two divergent crosses of chickpea under four environments in order to study the improvement of seed yield. Analysis of variance showed wide ranges of variability for all characters except days to maturity. Seed size (SSB) was found to be superior to single seed (SSD), followed by seed yield (YB), for developing high yielding lines. Fertility and spacing had no influence on the efficiency of any selection procedure indicating that selection under any environment is equally good. A part of the Ph.D. Thesis submitted to J. N. Krishi Vishwa Vidyalaya, Jabalpur-482 004, Madhya Pradesh, India     

Investigations on luminescence behaviour of Ce‐activated BaMgAl10O17 phosphor

The present paper describes the synthesis of cerium‐doped barium magnesium aluminate phosphor by combustion method. The crystal structure of synthesized phosphor belongs to the P6₃/mmc space group and is related to the β‐alumina structure. The photoluminescence emission spectra exhibited a broad peak centered at 440 nm showing the Ce³⁺ emission. The thermoluminescence properties of phosphors under ultraviolet irradiation were investigated. The activation energy was calculated by Chen's empirical method. Fracto‐mechanoluminescence properties were also investigated. The phosphor showed mechanoluminescence (ML) properties without irradiation and the ML intensity increased linearly with the impact height of the moving piston. Therefore this compound may have a use as a damage sensor. Copyright © 2016 John Wiley & Sons, Ltd.     

Microbial Transport, Survival, and Succession in a Sequence of Buried Sediments

Abstract Two chronosequences of unsaturated, buried loess sediments, ranging in age from <10,000 years to >1 million years, were investigated to reconstruct patterns of microbial ecological succession that have occurred since sediment burial. The relative importance of microbial transport and survival to succession was inferred from sediment ages, porewater ages, patterns of abundance (measured by direct counts, counts of culturable cells, and total phospholipid fatty acids), activities (measured by radiotracer and enzyme assays), and community composition (measured by phospholipid fatty acid patterns and Biolog substrate usage). Core samples were collected at two sites 40 km apart in the Palouse region of eastern Washington State, near the towns of Washtucna and Winona. The Washtucna site was flooded multiple times during the Pleistocene by glacial outburst floods; the Winona site elevation is above flood stage. Sediments at the Washtucna site were collected from near surface to 14.9 m depth, where the sediment age was approximately 250 ka and the porewater age was 3700 years; sample intervals at the Winona site ranged from near surface to 38 m (sediment age: approximately 1 Ma; porewater age: 1200 years). Microbial abundance and activities declined with depth at both sites; however, even the deepest, oldest sediments showed evidence of viable microorganisms. Same-age sediments had equal quantities of microorganisms, but different community types. Differences in community makeup between the two sites can be attributed to differences in groundwater recharge and paleoflooding. Estimates of the microbial community age can be constrained by porewater and sediment ages. In the shallower sediments (<9 m at Washtucna, <12 m at Winona), the microbial communities are likely similar in age to the groundwater; thus, microbial succession has been influenced by recent transport of microorganisms from the surface. In the deeper sediments, the populations may be considerably older than the porewater ages, since microbial transport is severely restricted in unsaturated sediments. This is particularly true at the Winona site, which was never flooded.     

Luminescence investigation of CaY2Al4SiO12:Dy3+ phosphor synthesized by sol–gel method

Dy³⁺-doped CaY₂Al₄SiO₁₂ phosphors were prepared using the sol–gel method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy analyses (EDS) were used to analyse the crystal structure, morphology, and elemental composition of the prepared samples. The luminescence behaviour of the sample was investigated using photoluminescence (PL) and thermoluminescence (TL) techniques. The prepared CaY₂Al₄SiO₁₂:xDy³⁺ phosphor showed a characteristic blue and yellow emission at ~480 and 583 nm, respectively, with an excitation wavelength of 350 nm. The most intense PL emission was found for a 4 mol% doping concentration of Dy³⁺ ions. The CIE diagram of the phosphor showed bluish-white colour emission. For TL studies, the prepared phosphors were irradiated with a ⁶⁰Co γ (gamma) source and the TL glow curve of the CaY₂Al₄SiO₁₂:0.04Dy³⁺ phosphor showed three overlapped peaks. For the Gaussian peaks, Chen's peak shape method was applied to determine the kinetic parameters of the samples.     

Mitogenic activity of pituitary hormones on cell cultures of normal and carcinogen-induced tumor epithelium from rat mammary glands

Cell suspension containing normal or tumor epithelium were readily obtained by enzymatically digesting rat mammary glands from perphenazine-treated (prolactin-hypersecreting) cycling, female virgin animals or hormone- responsive mammary tumors from animal treated with dimethylbenzanthracene. Cell suspensions were fractioned into predominantly epithelial and predominantly stromal cells by their differential rates of attachment to culture dishes. Both normal mammary and tumor epithelial cells were characterized by the presence of specific cell-junctional complexes, desmosome-like structures, surface microvilli, and their ability to synthesize casein. Serum-dependent protease activity was greater in cultures derived from tumors, and cells from such cultures grew in agarose whereas those from the non-neoplastic gland did not. The addition of prolactin to the culture medium stimulated DNA synthesis in primary or secondary epithelial cultures from tumors, whereas additional insulin and hydrocortisone with prolactin were required for similar levels of DNA synthesis in cultures from non-neoplastic glands. The fraction of cells synthesizing DNA was, however, smaller than that with 10 percent serum measured in the same time period. Both growth hormone and epidermal growth factor stimulated DNA synthesis but to a lesser extent than did prolactin. Prolactin with hydrocortisone and insulin were relatively inactive in promoting DNA synthesis of the nonepithelial cells whereas pituitary fibroblast growth factor was more active. These mitogenic effects were obtained when the hormones were added to the medium at near physiological concentrations, and paralleled the known activities of the hormones in control of mammary gland growth and development in the rat.