Impacts of Dry Season and Forest Fire 1997-1998 Episodes on Mixed Dipterocarp Forest at Bukit Bangkirai, East Kalimantan*[pengaruh Musim Kering Dan Kebakaran Hutan Episode 1997-1998 Terhadap Hutan Dipterocarp Campuran Di Bukit Bangkirai, Kalimantan Timur]

Kawasan Kalimantan Timur mengalami musim kemarau panjang yang merangsang terjadinya kebakaran hutan yang luas pada 1982-1983 dan 1997-1998.Naskah ini mengemukakan hasil penelitian di Bukit Bangkirai, Kalimantan Tengah mengenai dampak dari kemarau panjang dan kebakaran hutan 1997-1998 terhadap diversitas tumbuhan pohon hutan dipterokarp campuran.Penelitian dilakukan dengan cara memperbandinkan hasil pencacahan tumbuhan pohon berlingkar batang setinggi dada lebih daripada 15cm yang terdapat dalam tiga petak penelitian, masing-masing: lha di hutan alam yang tidak terbakar (K-plot), 0,3 ha di hutan yang terbakar ringan (LD) dan lha di hutan yang terbakar berat (HD).Hasil penelitian menunjukkan bahwa musim kemarau panjang 1997-1998 menyebabkan 12,02% mortalitas individual pohon di hutan alam yang tidak terbakar, yang terlihat dari pohon mati berdiri tegak akibat kekeringan, atau kehilangan 21,67% dari total basal area. Secara keseluruhan terlihat bahwa kebakaran hutan menyebabkan kerusakan berat terhadap struktur dan komposisi hutan. Secara kumulatif, kemarau panjang dan kebakaran hutan menyebabkan mortalitas individual pohon berkisar 36-70% dan kehilangan total basal area antara 45-85% dan menyebabkan lantai hutan terbuka terhadap penyinaran matahari langsung karena menurunnya penutupan tajuk sebesar 23-79%.Kebakaran hutan juga berdampak terhadap penurunan biodiversitas tumbuhan pohon sebesar 23-79% pada tingkat jenis, 53-66% pada tingkat marga dan 18-21% pada tingkat suku.Tercatat Perubahan komposisi jenis pada hutan yang terbakar; dominasi jenis Dipterocarpaceae dipetak hutan tak terbakar (K) menjadi dominasi pionir sekunder Macaranga gigantea-Vernonia arborea di petak terbakar berat (HD) dan dominasi Macaranga gigantea-Shorea smilhiana di petak terbakar ringan (LD).Beberapa jenis seperti Durio acutifolius dan Syzygium incarnaium mungkin dapat digolongkan sebagai jenis yang relative lebih tahan terhadap api

Characterisation of a recombinant β-xylosidase (xylA) from Aspergillus oryzae expressed in Pichia pastoris

β-xylosidases catalyse the hydrolysis of short chain xylooligosaccharides from their non-reducing ends into xylose. In this study we report the heterologous expression of Aspergillus oryzae β-xylosidase (XylA) in Pichia pastoris under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The recombinant enzyme was optimally active at 55°C and pH 4.5 with Km and Vmax values of 1.0 mM and 250 μmol min−1 mg−1 respectively against 4-nitrophenyl β-xylopyranoside. Xylose was a competitive inhibitor with a Ki of 2.72 mM, whereas fructose was an uncompetitive inhibitor reducing substrate binding affinity (Km) and conversion efficiency (Vmax). The enzyme was characterised to be an exo-cutting enzyme releasing xylose from the non-reducing ends of β-1,4 linked xylooligosaccharides (X2, X3 and X4). Catalytic conversion of X2, X3 and X4 decreased (Vmax and kcat) with increasing chain length

Planet Sensitivity from Combined Ground- and Space-based Microlensing Observations

To move one step forward toward a Galactic distribution of planets, we present the first planet sensitivity analysis for microlensing events with simultaneous observations from space and the ground. We present this analysis for two such events, OGLE-2014-BLG-0939 and OGLE-2014-BLG-0124, which both show substantial planet sensitivity even though neither of them reached high magnification. This suggests that an ensemble of low to moderate magnification events can also yield significant planet sensitivity and therefore probability to detect planets. The implications of our results to the ongoing and future space-based microlensing experiments to measure the Galactic distribution of planets are discussed.Comment: 10 pages, 5 figures, 1 table; ApJ in pres

Heterotopic gastrointestinal cyst mimicking chronic cholecystitis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Heterotopic gastric mucosa is described almost everywhere in the gastrointestinal tract, from the oral cavity to the rectum. The occurrence of heterotopic gastric tissue in the gallbladder is rare. A choristoma can be defined as a new growth developing from a displaced anlage not normally present in the anatomical site where it developed. We present an extremely uncommon case of a cyst (choristoma) attached to the gallbladder, which contained gastric and intestinal mucosa.</p> <p>Case presentation</p> <p>A 33-year-old woman was hospitalized with clinical symptoms of chronic cholecystitis. The laboratory findings were within the normal range. Abdominal ultrasonography revealed a thickened gallbladder wall and a stone in the cystic duct was suspected. In the course of laparoscopic cholecystectomy, a cyst was visualized in the vicinity of the duct and the gallbladder neck. Microscopic examination of the removed cyst revealed evidence of gastric, duodenal and small-intestinal mucosa. The immunohistochemical study revealed many endocrine cells, which were positive for several endocrine cell markers such as chromogranin, serotonin, gastrin and so on. It can be inferred that the observed cyst had arisen from the foregut early in the development of the gastrointestinal tract.</p> <p>Conclusion</p> <p>The presence of endocrine cells together with epithelial cells supports the hypothesis that these had developed simultaneously, and that the endocrine cells had probably supported the development of the epithelial cells by the release of hormones and growth factors. To the best of the authors' knowledge, this report is the first to report a gastrointestinal cyst choristoma with endocrine cells in the region of the cystic duct and gallbladder.</p

Generation of Germline-Competent Rat Induced Pluripotent Stem Cells

Recent progress in rat pluripotent stem cell technology has been remarkable. Particularly salient is the demonstration that embryonic stem cells (ESCs) in the rat (rESCs) can contribute to germline transmission, permitting generation of gene-modified rats as is now done using mouse ESCs (mESCs) or mouse induced pluripotent stem cells (iPSCs; miPSCs). However, determinations of whether rat iPSCs (riPSCs) can contribute to germ cells are not published. Here we report the germline competency of riPSCs.We generated riPSCs by transducing three mouse reprogramming factors (Oct3/4, Klf4, and Sox2) into rat somatic cells, followed by culture in the presence of exogenous rat leukemia inhibitory factor (rLIF) and small molecules that specifically inhibit GSK3, MEK, and FGF receptor tyrosine kinases. We found that, like rESCs, our riPSCs can contribute to germline transmission. Furthermore we found, by immunostaining of testis from mouse-rat interspecific chimeras with antibody against mouse vasa homolog, that riPSCs can contribute to embryonic development with chimera formation in mice (rat-mouse interspecific chimeras) and to interspecific germlines.Our data clearly demonstrate that using only three reprogramming factors (Oct3/4, Klf4, and Sox2) rat somatic cells can be reprogrammed into a ground state. Our generated riPSCs exhibited germline transmission in either rat-rat intraspecific or mouse-rat interspecific chimeras

A novel xylan degrading β-D-xylosidase: purification and biochemical characterization

Aspergillus ochraceus, a thermotolerant fungus isolated in Brazil from decomposing materials, produced an extracellular b-xylosidase that was purified using DEAE-cellulose ion exchange chromatography, Sephadex G-100 and Biogel P-60 gel filtration. b-xylosidase is a glycoprotein (39 % carbohydrate content) and has a molecular mass of 137 kDa by SDS-PAGE, with optimal temperature and pH at 70 C and 3.0–5.5, respectively.b-xylosidase was stable in acidic pH (3.0–6.0) and 70 C for 1 h. The enzyme was activated by 5 mM MnCl2 (28 %)and MgCl2 (20 %) salts. The b-xylosidase produced by A. ochraceus preferentially hydrolyzed p-nitrophenyl-b- D-xylopyranoside, exhibiting apparent Km and Vmax values of 0.66 mM and 39 U (mg protein)-1 respectively, and to a lesser extent p-nitrophenyl-b-D-glucopyranoside. The enzyme was able to hydrolyze xylan from different sources,suggesting a novel b-D-xylosidase that degrades xylan. HPLC analysis revealed xylans of different compositions which allowed explaining the differences in specificity observed by b-xylosidase. TLC confirmed the capacity.This work was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), and the Conselho de Desenvolvimento Científico e Tecnológico (CNPq). J. A. J. and M. L. T. M. P are Research Fellows of CNPq. M. M. was a recipient of a FAPESP fellowship and this work is part of her Doctoral Thesis. It is also part of the project SISBIOTA CNPq: 563260/2010-6 and FAPESP: 2010/52322-3

Adaptation and Validation of QUick, Easy, New, CHEap, and Reproducible (QUENCHER) Antioxidant Capacity Assays in Model Products Obtained from Residual Wine Pomace

Evaluation of the total antioxidant capacity of solid matrices without extraction steps is a very interesting alternative for food researchers and also for food industries. These methodologies have been denominated QUENCHER from QUick, Easy, New, CHEap, and Reproducible assays. To demonstrate and highlight the validity of QUENCHER (Q) methods, values of Q-method validation were showed for the first time, and they were tested with products of well-known different chemical properties. Furthermore, new QUENCHER assays to measure scavenging capacity against superoxide, hydroxyl, and lipid peroxyl radicals were developed. Calibration models showed good linearity (R2 > 0.995), proportionality and precision (CV < 6.5%), and acceptable detection limits (<20.4 nmol Trolox equiv). The presence of ethanol in the reaction medium gave antioxidant capacity values significantly different from those obtained with water. The dilution of samples with powdered cellulose was discouraged because possible interferences with some of the matrices analyzed may take place.The autonomous government of Castilla y León (Project BU268A11-2

microRNA-Mediated Messenger RNA Deadenylation Contributes to Translational Repression in Mammalian Cells

Animal microRNAs (miRNAs) typically regulate gene expression by binding to partially complementary target sites in the 3′ untranslated region (UTR) of messenger RNA (mRNA) reducing its translation and stability. They also commonly induce shortening of the mRNA 3′ poly(A) tail, which contributes to their mRNA decay promoting function. The relationship between miRNA-mediated deadenylation and translational repression has been less clear. Using transfection of reporter constructs carrying three imperfectly matching let-7 target sites in the 3′ UTR into mammalian cells we observe rapid target mRNA deadenylation that precedes measureable translational repression by endogenous let-7 miRNA. Depleting cells of the argonaute co-factors RCK or TNRC6A can impair let-7-mediated repression despite ongoing mRNA deadenylation, indicating that deadenylation alone is not sufficient to effect full repression. Nevertheless, the magnitude of translational repression by let-7 is diminished when the target reporter lacks a poly(A) tail. Employing an antisense strategy to block deadenylation of target mRNA with poly(A) tail also partially impairs translational repression. On the one hand, these experiments confirm that tail removal by deadenylation is not strictly required for translational repression. On the other hand they show directly that deadenylation can augment miRNA-mediated translational repression in mammalian cells beyond stimulating mRNA decay. Taken together with published work, these results suggest a dual role of deadenylation in miRNA function: it contributes to translational repression as well as mRNA decay and is thus critically involved in establishing the quantitatively appropriate physiological response to miRNAs

Mathematical modeling of microRNA-mediated mechanisms of translation repression

MicroRNAs can affect the protein translation using nine mechanistically different mechanisms, including repression of initiation and degradation of the transcript. There is a hot debate in the current literature about which mechanism and in which situations has a dominant role in living cells. The worst, same experimental systems dealing with the same pairs of mRNA and miRNA can provide ambiguous evidences about which is the actual mechanism of translation repression observed in the experiment. We start with reviewing the current knowledge of various mechanisms of miRNA action and suggest that mathematical modeling can help resolving some of the controversial interpretations. We describe three simple mathematical models of miRNA translation that can be used as tools in interpreting the experimental data on the dynamics of protein synthesis. The most complex model developed by us includes all known mechanisms of miRNA action. It allowed us to study possible dynamical patterns corresponding to different miRNA-mediated mechanisms of translation repression and to suggest concrete recipes on determining the dominant mechanism of miRNA action in the form of kinetic signatures. Using computational experiments and systematizing existing evidences from the literature, we justify a hypothesis about co-existence of distinct miRNA-mediated mechanisms of translation repression. The actually observed mechanism will be that acting on or changing the limiting "place" of the translation process. The limiting place can vary from one experimental setting to another. This model explains the majority of existing controversies reported.Comment: 40 pages, 9 figures, 4 tables, 91 cited reference. The analysis of kinetic signatures is updated according to the new model of coupled transcription, translation and degradation, and of miRNA-based regulation of this process published recently (arXiv:1204.5941). arXiv admin note: text overlap with arXiv:0911.179

Spitzer Observations Of Ogle-2015-blg-1212 Reveal A New Path Toward Breaking Strong Microlens Degeneracies

Spitzer microlensing parallax observations of OGLE-2015-BLG-1212 decisively break a degeneracy between planetary and binary solutions that is somewhat ambiguous when only ground-based data are considered. Only eight viable models survive out of an initial set of 32 local minima in the parameter space. These models clearly indicate that the lens is a stellar binary system possibly located within the bulge of our Galaxy, ruling out the planetary alternative. We argue that several types of discrete degeneracies can be broken via such space-based parallax observations