Miracle-dz/UniFAR-FTUs huggingface dataset:
Cobalamin-dependent methionine synthase from Escherichia coli: involvement of zinc in homocysteine activation.

Methionine synthase (MetH) is a modular protein with at least four distinct regions; amino acids 2-353 comprise a region responsible for binding and activation of homocysteine, amino acids 345-649 are thought to be involved in the binding and activation of methyltetrahydrofolate, amino acids 650-896 are responsible for binding of the prosthetic group methylcobalamin, and amino acids 897-1227 are involved in binding adensylmethionine and are required for reductive activation of enzyme in the cob(II)alamin form. Previous studies have shown that mutations of Cys310 or Cys311 to either alanine or serine result in loss of all detectable catalytic activity. These mutant proteins retain the ability to catalyze methyl transfer from methyltetrahydrofolate to exogenous cob(I)alamin, but have lost the ability to transfer methyl groups from exogenous methylcobalamin to homocysteine [Goulding, C. W. , Postigo, D. , and Matthews, R. G. (1997) Biochemistry 36, 8082-8091]. We now demonstrate that both MetH holoenzyme and a truncated MetH(2-649) protein, which lacks a cobalamin prosthetic group, contain 0.9 equiv of zinc, while the Cys310Ser and Cys311Ser mutant proteins contain less than 0.05 equiv of zinc. Addition of l-homocysteine to MetH(2-649) is accompanied by release of 1 equiv of protons/mol of protein, while addition of l-homocysteine to the Cys310Ser and Cys311Ser mutant truncated proteins does not result in proton release. The Cys310Ala and Cys311Ala mutant methylcobalamin holoenzymes have completely lost the ability to transfer the methyl group from methylcobalamin to homocysteine, suggesting that zinc is required for this reaction. Further evidence that zinc is required for catalytic activity comes from experiments in which the zinc is removed from MetH(2-1227). Removal of zinc from methylated wild-type holoenzyme by treatment with methyl methanethiolsulfonate and then with dithiothreitol and EDTA results in loss of the ability of the protein to catalyze methyl transfer from methyltetrahydrofolate to homocysteine. Reconstitution of the zinc-depleted holoenzyme results in incorporation of 0.4 equiv of zinc/mol of protein and partial restoration of the ability of the protein to catalyze homocysteine methylation.
Expression and functional properties of unique inward rectifier K+ channel Kir7.1 in the porcine iris and retinal pigment epithelium

Purpose. To investigate the membrane functional properties of porcine iris pigment epithelial cells (IPE), and compare the characters of inward rectifier potassium (Kir) channel in the IPE with those in the retinal pigment epithelial cells (RPE). Methods. IPE and RPE were acutely dissociated from porcine eyes. Functional properties of Kir channels were characterized using whole cell patch clamp recording techniques. Expression of Kir7.1 mRNA in both cells was detected by reverse transcription-polymerase chain reaction (RT-PCR). Results. Whole cell current in the IPE exhibited a mild inward K + rectification, and showed little dependence on [K + ] o. Unusual high (7.04 ± 1.7) Rb + to K + inward conductance ratio indicated that Kir7.1 subunit was expressed in the IPE as the same as RPE cells. Also, Kir7.1 mRNA was detected in both porcine IPE and RPE by RT-PCR. However, functional expression of Kir conductance in IPE cells (21.7 S/F) was much smaller than that in RPE cells (205.6 S/F). Conclusions. The Kir7.1 subunit was predominantly expressed in the acutely dissociated porcine IPE and its functional properties are similar to those in the RPE. However, the current density seems too small to fulfill the task of the Kir function of RPE.
Cooperative spectrum sensing with enhanced energy detection under GAUSSIAN noise uncertainty in cognitive radios

This paper presents optimization issues of energy detection (ED) thresholds in cooperative spectrum sensing (CSS) with regard to general Gaussian noise. Enhanced ED thresholds are proposed to overcome sensitivity of multiple noise uncertainty. Two-steps decision pattern and convex samples thresholds have been put forward under Gaussian noise uncertainty. Through deriving the probability of detection (Pd) and the probability of false alarm (Pf ) for independent and identical distribution (i.i.d.) SUs, we obtain lower total error rate (Qe) with proposed ED thresholds at low signal-to-noise-ratio (SNR) condition. Furthermore, simulation results show that proposed schemes outperform most other noise uncertainty plans.
N. M. A.

Inevitably, reading is one of the requirements to be undergone. To improve the performance and quality, someone needs to have something new every day. It will suggest you to have more inspirations, then. However, the needs of inspirations will make you searching for some sources. Even from the other people experience, internet, and many books. Books and internet are the recommended media to help you improving your quality and performance.
Development of retrovirus vectors useful for expressing genes in cultured murine embryonal cells and hematopoietic cells in vivo

A series of retrovirus vectors were constructed in which cellular promoter elements derived from the chicken beta-actin and human histone H4 genes were introduced within the proviral transcriptional unit of Moloney murine leukemia virus in order to promote expression of inserted sequences. Each of these vectors gave rise to high titer of virus capable of transferring the expected proviral structure to cells. Inclusion of normal 5' splice sequences or a portion of viral gag sequences in these constructions resulted in significant increases in virus titer. Each construction was transcriptionally active in NIH 3T3 cells and in undifferentiated F9 cells. One of the vectors, HSG-neo, which contained the human histone H4 promoter, was shown to be transcriptionally active in hematopoietic cells derived from long-term reconstituted bone marrow transplant recipients engrafted with transduced stem cells. These vectors should be of general use for obtaining efficient gene expression in embryonal and hematopoietic cells.
Tetranucleotide repeats identify novel virulence determinant homologues in Neisseria meningitidis.

Numerous outer membrane components of Neisseria meningitidis and N. gonorrhoeae exhibit phase variable expression (the rapid, reversible on/off switching of phenotypic expression). Many of the genes encoding these outer membrane components contain simple repetitive DNA motifs (mononucleotides, dinucleotides, tetranucleotides and other repeats) which mediate this variation. One such repeat motif, the tetranucleotide 5;-(GCAA)n-3;, is associated with phase-variable LPS biosynthetic genes in the pathogen Haemophilus influenzae. We have previously shown that N. meningitidis strain MC58 contains this repeat motif in at least three distinct genetic loci. In this study all three of these loci were investigated: two were cloned and identified as novel loci and designated nmrep1 and nmrep2. The third locus was assigned to a previously cloned gene and here is designated nmrep3. The distribution of these loci, and the number of repeat units at each locus was investigated in a range of strains. This analysis revealed that the nmrep1 and nmrep2 loci are present in all 45 strains examined, with 41/45 containing nmrep3. Sequences associated with nmrep1 showed no homology with reported proteins, but amino acid sequences of open reading frames of nmrep2 and nmrep3 exhibited sequence homology to the adhesins Aida of Escherichia coli and Prn of Bordetella sppand IcsA of Shigella flexneri which is involved in intracellular spread.
Identification of dissolved organic matter in raw water supply from reservoirs and canals as precursors to trihalomethanes formation

The characteristic and quantity of dissolved organic matter (DOM) as trihalomethanes precursors in water from the U-Tapao Basin, Songkhla, Thailand was investigated. The sources of water in the basin consisted of two reservoirs and the U-Tapao canal. The canal receives water discharge from reservoirs, treated and untreated wastewater from agricultural processes, communities and industries. Water downstream of the canal is utilized as a raw water supply. Water samples were collected from two reservoirs, upstream and midstream of the canal, and the raw water supply in the rainy season and summer. The DOM level in the canal water was higher than that of the reservoir water. The highest trihalomethane formation potential (THMFP) was formed in the raw water supply. Fourier-transform infrared peaks of the humic acid were detected in the reservoir and canal waters. Aliphatic hydrocarbon and organic nitrogen were the major chemical classes in the reservoir and canal water characterized by a pyrolysis gas chromatography mass spectrometer. The optimal condition of the poly aluminum chloride (PACl) coagulation was obtained at a dosage of 40 mg/L at pH 7. This condition could reduce the average UV-254 to 57%, DOC to 64%, and THMFP to 42%. In the coagulated water, peaks of O-H groups or H-bonded NH, C˭O of cyclic and acyclic compounds, ketones and quinines, aromatic C˭C, C-O of alcohols, ethers, and carbohydrates, deformation of COOH, and carboxylic acid salts were detected. The aliphatic hydrocarbon, organic nitrogen and aldehydes and ketones were the major chemical classes. These DOM could be considered as the prominent DOM for the water supply plant that utilized PACl as a coagulant.
Screening of phytochemical content of commercial apricot- and orange-based beverages and its relationship with antioxidant capacity.

The aim of the present research study was to compare the antioxidant properties of beverages based on apricot and orange fruits as well as to establish if the combination of these resulted in a beverage with high antioxidant content. For this purpose, the quantification of some antioxidants (total phenolic compounds (TP), ascorbic acid (AA) and proanthocianidins (PA)) using colorimetric assays and the determination of antioxidant activities of apricotand orange-based beverages as well as their mixture were performed. The results revealed that the combination of apricotand orange-based beverages had antagonistic effect on TP and AA content, unlike PA content. Moreover, these antioxidants correlated positively with total antioxidant capacity. The principal component analysis showed cumulative variance of approximately 85% which mean that the chosen parameters had a high discriminate power and they can be a useful criterion for the determination of quality of commercial beverages.
A Beginner's Guide to Structural Equation Modeling

tical methods. The book does a good job explaining some fundamental computational methods in statistics and econometrics. I have no doubt that this book will serve students well as a reference book for upper-level undergraduate courses or graduate courses in computational statistics, time series analysis, or econometrics. Students will appreciate the material, and I will certainly list this book as a reference book for my first-year graduate computational statistics class.
Amino acid intrinsic α‐helical propensities III: Positional dependence at several positions of C terminus

In this study, we have analyzed experimentally the helical intrinsic propensities of noncharged and nonaromatic residues at different C‐terminal positions (C1, C2, C3) of an Ala‐based peptide. The effect was found to be complex, resulting in extra stabilization or destabilization, depending on guest amino acid and position under consideration. Polar (Ser, Thr, Cys, Asn, and Gln) amino acids and Gly were found to have significantly larger helical propensities at several C‐terminal positions compared with the α‐helix center (−1.0 kcal/mole in some cases). Some of the nonpolar residues, especially β‐branched ones (Val and Ile) are significantly more favorable at position C3 (−0.3 to −0.4 kcal/mole), although having minor differences at other C‐terminal positions compared with the α‐helix center. Leu has moderate (−0.1 to −0.2 kcal/mole) stabilization effects at position C2 and C3, whereas being relatively neutral at C1. Finally, Met was found to be unfavorable at C1 and C2 ( +0.2 kcal/mole) and favorable at C3 (−0.2 kcal/mole). Thus, significant differences found between the intrinsic helical propensities at the C‐terminal positions and those in the α‐helix center must be accounted for in helix/coil transition theories and in protein design.
Merkel cell carcinoma: recent insights and new treatment options

Purpose of review Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin demonstrating a high propensity of recurrence and metastasis. Its 5-year disease-specific survival rate is only about 60%. Although MCC is still regarded as a very rare tumor entity, its incidence is rapidly increasing. In this regard, the American Cancer Society estimated almost 1500 new cases in the United States in 2008. Recent findings The newly identified Merkel cell polyomavirus (MCV) has been found associated to most MCC cases. Nevertheless, the distinct molecular pathogenesis of MCC and its link to MCV is not yet fully understood. Moreover, the impact of MCV positivity on the course of disease and prognosis of MCC patients is controversially discussed. Summary This review summarizes recent findings on MCC pathogenesis with a special emphasis on the impact of MCV, presents an overview of clinical aspects, and discusses treatment options.
The association between obstructive sleep apnea and neurocognitive performance--the Apnea Positive Pressure Long-term Efficacy Study (APPLES).

STUDY OBJECTIVES To determine associations between obstructive sleep apnea (OSA) and neurocognitive performance in a large cohort of adults. STUDY DESIGN Cross-sectional analyses of polysomnographic and neurocognitive data from 1204 adult participants with a clinical diagnosis of obstructive sleep apnea (OSA) in the Apnea Positive Pressure Long-term Efficacy Study (APPLES), assessed at baseline before randomization to either continuous positive airway pressure (CPAP) or sham CPAP. MEASUREMENTS Sleep and respiratory indices obtained by laboratory polysomnography and several measures of neurocognitive performance. RESULTS Weak correlations were found for both the apnea hypopnea index (AHI) and several indices of oxygen desaturation and neurocognitive performance in unadjusted analyses. After adjustment for level of education, ethnicity, and gender, there was no association between the AHI and neurocognitive performance. However, severity of oxygen desaturation was weakly associated with worse neurocognitive performance on some measures of intelligence, attention, and processing speed. CONCLUSIONS The impact of OSA on neurocognitive performance is small for many individuals with this condition and is most related to the severity of hypoxemia.
Slowing of relaxation and [Ca2+]i during prolonged tetanic stimulation of single fibres from Xenopus skeletal muscle.

1. Parvalbumin (PA) has been proposed to take up Ca2+ and enhance skeletal muscle relaxation in brief contractions; as the duration of the contraction is increased, PA will become saturated with Ca2+ and no longer contribute to relaxation which therefore will be slowed. The rate of Ca2+ loading of PA is determined by the Mg2+ off rate (about 4 s‐1 at 22 degrees C). In the present study we produced prolonged tetani in intact, single fibres of Xenopus frogs while measuring force and the free myoplasmic [Ca2+] ([Ca2+]i) with indo‐1. 2. Mean rate constants of slowing of force relaxation with increasing tetanus duration ranged between 3.2 and 4.8 s‐1, thus, similar to the Mg2+ off rate of PA. 3. The amplitude of the tail of [Ca2+]i after tetani increased with tetanus duration. This increase developed with a rate constant similar to the Mg2+ off rate of PA 4. Steady‐state force‐[Ca2+]i curves were produced from tetani of various frequencies and tetani produced when force was depressed after fatiguing stimulation. These curves were used to convert [Ca2+]i records into Ca(2+)‐derived force. Relaxation of Ca(2+)‐derived force was slowed following a time course similar to that of real force. The lag between Ca(2+)‐derived and real force during relaxation was not affected by tetanus duration. 5. Tails of elevated [Ca2+]i after tetani were used to analyse the function of the SR Ca2+ pumps. This analysis showed a marked decline in the rate of Ca2+ uptake with prolonged tetani. 6. In conclusion, in Xenopus fibres the slowing of relaxation with increasing tetanus duration can be explained by altered Ca2+ handling due to PA Ca2+ loading and impaired SR Ca2+ uptake. This contrasts to our previous results in mouse fibres and the difference can be explained by a markedly lower rate of SR Ca2+ uptake resulting in higher tetanic [Ca2+]i in Xenopus fibres.
The use of irony as a subversive element in suffrage theatre

ABSTRACT This article seeks to explore how the use of comic irony in suffrage plays might be understood as a subversive element. Pro-suffrage playwrights wrote their propaganda plays in such a way as to ensure that they were funny, mocking and entertaining, whilst at the same time critiquing the social situation of women. Comic irony was used as a tool to convince audiences of the legitimate grievances of women through the use of humour, thereby turning irony into a subversive tool.
Seasonal spermatogenic cycle and morphology of germ cells in the viviparous lizard Mabuya brachypoda (Squamata, Scincidae)

We describe seasonal variations of the histology of the seminiferous tubules and efferent ducts of the tropical, viviparous skink, Mabuya brachypoda, throughout the year. The specimens were collected monthly, in Nacajuca, Tabasco state, Mexico. The results revealed strong annual variations in testicular volume, stages of the germ cells, and diameter and height of the epithelia of seminiferous tubules and efferent ducts. Recrudescence was detected from November to December, when initial mitotic activity of spermatogonia in the seminiferous tubules were observed, coinciding with the decrease of temperature, photoperiod and rainy season. From January to February, early spermatogenesis continued and early primary and secondary spermatocytes were developing within the seminiferous epithelium. From March through April, numerous spermatids in metamorphosis were observed. Spermiogenesis was completed from May through July, which coincided with an increase in temperature, photoperiod, and rainfall. Regression occurred from August through September when testicular volume and spermatogenic activity decreased. During this time, the seminiferous epithelium decreased in thickness, and germ cell recruitment ceased, only Sertoli cells and spermatogonia were present in the epithelium. Throughout testicular regression spermatocytes and spermatids disappeared and the presence of cellular debris, and scattered spermatozoa were observed in the lumen. The regressed testes presented the total suspension of spermatogenesis. During October, the seminiferous tubules contained only spermatogonia and Sertoli cells, and the size of the lumen was reduced, giving the appearance that it was occluded. In concert with testis development, the efferent ducts were packed with spermatozoa from May through August. The epididymis was devoid of spermatozoa by September. M. brachypoda exhibited a prenuptial pattern, in which spermatogenesis preceded the mating season. The seasonal cycle variations of spermatogenesis in M. brachypoda are the result of a single extended spermiation event, which is characteristic of reptilian species. J. Morphol. © 2012 Wiley Periodicals, Inc.
Feeling Pain in the Rubber Hand: Integration of Visual, Proprioceptive, and Painful Stimuli

The visual capture phenomenon has recently been explored, especially in the context of the rubber-hand illusion (RHI)—an illusion in which tactile sensations are referred to an illusory limb. We have induced the RHI with the difference that tactile-painful stimuli were added in order to verify the interaction between vision, touch, proprioception, and pain. Thirty volunteers were used. We found that tactile-painful stimuli could cause the same illusion as purely tactile stimuli. This result suggests that localisation of pain may also be distorted by spurious visual cues. The implications of this finding for distorted human proprioception (as in amputees with phantom pain or limbs) are discussed.
Is the fast/slow allozyme variation at the Adh locus of Drosophila melanogaster an ancient balanced polymorphism?

Any general model of population genetics must be able to accommodate observations both of standing variation (polymorphism) and of evolutionary history (divergence). Interpretation of the connection (or lack thereof) between these two kinds of data impinges directly on our ideas of evolutionary mechanism. Studies of the alcohol dehydrogenase locus (Adh) in Drosophila melanogaster and its close relatives provide what is perhaps our most detailed description of variation and evolution of a gene at the molecular and phenotypic levels. There is abundant evidence that two common electrophoretic variants in D. melanogaster populations caused by a threonine (Fast)/lysine (Slow) polymorphism at codon 192 have different biochemical properties and are currently under some form of variable selection (reviewed in Powell 1997). Other polymorphisms at the locus may also be current targets of natural selection (Berry and Kreitman 1993), and epistatic effects among some of these polymorphisms must be considered (Stam and Laurie 1996). Molecular population genetic studies of Adh have revealed at least four interesting patterns. First, some fraction of the amino acid evolution in the melanogaster subgroup has been caused by natural selection (McDonald and Kreitman 1991). Second, a peak of excess silent polymorphisms is found at nucleotide sites that are closely linked to the Fast/ Slow polymorphism in D. melanogaster. The excess polymorphisms are incompatible with neutral molecular evolution; however, a model of balancing selection fits the data well (Kreitman and Hudson 1991). Third, the Fast electromorph in D. melanogaster appears to have increased in frequency in the recent past, as Fast haplotypes harbor little silent polymorphism and show little sequence divergence from Slow haplotypes (Kreitman 1983; Aquadro et al. 1986). Finally, correlated evolution of particular sites among different lineages suggests that epistatic selection acts on some property of Adh transcripts (Parsch, Tanda, and Stephan 1997). One message from these molecular analyses is that the evolutionary history of Adh is as complex as it is interesting. Despite the wealth of accumulated knowledge about Adh polymorphism and divergence, several questions remain. One of the mysteries associated with Adh nucleotide variation in D. melanogaster is the observation by Kreitman and Aguade (1986) and Kreitman and Hudson (1991)