Miracle-dz/UniFAR-FTUs huggingface dataset:
Optimization of dextran production by Leuconostoc mesenteroides NRRL B‐512 using cheap and local sources of carbohydrate and nitrogen

Using pure components for the fermentation medium in dextran production imposes high costs on the industry. In the present study, the economic production of dextran using local and cheap sources of carbohydrate and nitrogen was investigated. Different concentrations of molasses and wheat‐bran extract, after filtration, steam sterilization and pH adjustment, were inoculated with a fresh suspension of Leuconostoc mesenteroides. Cultures were incubated, and then diluted with an equal volume of ethanol. The bacteria were pelleted, and an aliquot of the supernatant was diluted with ethanol and dextran was precipitated. The supernatant was removed and the precipitate was dissolved in a minimal volume of water. Activated charcoal was added and the solution was boiled. The solution was filtered and protein impurities removed by 2‐methylbutan‐2‐ol/chloroform extraction. Dextran was again precipitated with cold ethanol as described above, and the precipitate was dried in a desiccator. Optimum conditions and composition of culture media for dextran production using sugar‐beet molasses and wheat bran were determined. The best results were obtained when 20% (w/v) molasses and 15% (w/v) wheat bran were used. The optimal initial pH for dextran production was 7.5.
Constitutive HSP70: Oligomerization and its dependence on ATP binding

The constitutive HSP70 purified from CHO cells, which indicated a single band in SDS‐polyacrylamide gel electrophoresis, showed multiple bands in native‐polyacrylamide gel electrophoresis. These results indicate that the protein may exist in oligomeric forms. After crosslinking the oligomers with glutaraldehyde, SDS‐polyacrylamide gel electrophoresis showed three protein bands of molecular weight 70 kDa, 153 kDa, and 200 kDa corresponded to monomer, dimer, and trimer, respectively. The relative amount of oligomeric forms was dependent upon ATP concentrations: it increased upon hydrolysis of ATP or decreased upon incubation with high concentrations of ATP (1–10 mM). Autoradiographic analysis of the native polyacrylamide gel electrophoresis of HSP70 following incubation with [γ‐32P]ATP revealed that ATP bound to only monomer. These results suggest that the equilibrium between oligomeric forms is dependent on ATP concentrations. Nonetheless, during heat shock, both monomer and oligomer might be indistinguishably associated with some proteins, probably denatured proteins. © 1992 Wiley‐Liss, Inc.
Role for Nhp6, Gcn5, and the Swi/Snf Complex in Stimulating Formation of the TATA-Binding Protein-TFIIA-DNA Complex

ABSTRACT The TATA-binding protein (TBP), TFIIA, and TFIIB interact with promoter DNA to form a complex required for transcriptional initiation, and many transcriptional regulators function by either stimulating or inhibiting formation of this complex. We have recently identified TBP mutants that are viable in wild-type cells but lethal in the absence of the Nhp6 architectural transcription factor. Here we show that many of these TBP mutants were also lethal in strains with disruptions of either GCN5, encoding the histone acetyltransferase in the SAGA complex, or SWI2, encoding the catalytic subunit of the Swi/Snf chromatin remodeling complex. These synthetic lethalities could be suppressed by overexpression of TOA1 and TOA2, the genes encoding TFIIA. We also used TFIIA mutants that eliminated in vitro interactions with TBP. These viable TFIIA mutants were lethal in strains lacking Gcn5, Swi2, or Nhp6. These lethalities could be suppressed by overexpression of TBP or Nhp6, suggesting that these coactivators stimulate formation of the TBP-TFIIA-DNA complex. In vitro studies have previously shown that TBP binds very poorly to a TATA sequence within a nucleosome but that Swi/Snf stimulates binding of TBP and TFIIA. In vitro binding experiments presented here show that histone acetylation facilitates TBP binding to a nucleosomal binding site and that Nhp6 stimulates formation of a TBP-TFIIA-DNA complex. Consistent with the idea that Nhp6, Gcn5, and Swi/Snf have overlapping functions in vivo, nhp6a nhp6b gcn5 mutants had a severe growth defect, and mutations in both nhp6a nhp6b swi2 and gcn5 swi2 strains were lethal.
On-line spatio-temporal independent component analysis for motion correction in renal DCE-MRI

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) renography, in common with other medical imaging techniques, is influenced by respiratory motion. As a result, data quantification may be inaccurate. This work presents a novel on-line approach for motion correction by implementing a spatio-temporal independent component analysis method (STICA). This methodology firstly results in removal of motion artefacts and secondly provides independent components that have physiological characteristics. The STICA was applied to 10 healthy volunteers' renal DCE-MRI data. The results were evaluated using independent component curve gradients (lCGs) from different regions of interest and by comparing them with the Rutland-Patlak (RP) analysis. The r2 values for the lCGs were significantly higher compared to the RP curves. The standard deviations of the IC curve gradients also showed less dispersion with comparison to the RP curve gradients across all the ten volunteers' renal data.
Acidosis Counteracts the Negative Inotropic Effect of K+ on Ventricular Muscle Strips from the Toad Bufo marinus

Strenuous activity is associated with acidosis, increased extracellular potassium concentration ([K+]o), and elevated levels of circulating catecholamines. Acidosis and elevated [K+]o are normally considered harmful to cardiac function, and a high sympathetic tone on the heart may lead to arrhythmia. During activity, however, the heart must be able to increase rate and strength of contraction. While the individual effects of [K+]o, acidosis, and adrenaline on contractile properties of cardiac muscle have been characterized for some ectothermic species, less information is available on their interactions. Here we examine the isolated and combined effects of [K+]o, acidosis, and adrenaline on ventricular muscle strips from the toad Bufo marinus. This study showed that increased [K+]o significantly reduced twitch force, while lactic acid significantly increased twitch force and more than counteracted the negative inotropic effects of elevated [K+]o. There was no inotropic effect of Na‐lactate (neutralized lactic acid), which suggests that lactic acid stimulated twitch force through reduced pH and not by serving as a substrate. Adrenaline had a positive effect on twitch force in all preparations. Irrespective of treatment, twitch force decreased as stimulation rate increased. During high [K+]o, there was a severe reduction in maximal frequency of toad ventricular strips that was not alleviated by lactic acidosis and/or adrenaline, which suggests that high [K+]o influences twitch force and maximal rate by different mechanisms. In vivo levels of lactic acid, [K+]o, adrenaline, and heart rate previously observed during forced activity in Bufo did not significantly affect the contractile properties of heart muscle strips in vitro. Thus, although [K+]o significantly decreased twitch force, this detrimental effect was more than counteracted by the positive inotropic effect of lactic acid and adrenaline.
Effects of circulating IGF-I on glucose and amino acid kinetics in the ovine fetus.

To investigate the role of insulin-like growth factor I (IGF-I) in the regulation of fetal metabolism, the kinetics of leucine, phenylalanine, and glucose were assessed in the chronically catheterized ovine fetus (0.85 gestation) before and during infusion of recombinant human IGF-I (rhIGF-I). Substrate kinetics were determined by tracer dilution. rhIGF-I was infused at 6.7 nmol.kg fetus-1.h-1. Fetal insulin and growth hormone concentrations were significantly decreased by 50% during rhIGF-I infusion. Net umbilical glucose uptake was unchanged, and glucose rate of appearance increased in the fed state only. There were no changes in the net umbilical uptakes of leucine or phenylalanine, but the rates of appearance of both declined during rhIGF-I infusion, indicative of decreased fetal protein breakdown (Ra,Leu 45.4 +/- 1.40 to 40 +/- 1.4 mumol/min in the fed state, 43 +/- 1.5 to 37 +/- 1.5 mumol/min in the fasted state; Ra,Phe 10.7 +/- 0.3 to 10.4 +/- 0.3 mumol/min in the fed state and from 10.7 +/- 0.3 to 9.8 +/- 0.3 mumol/min in the fasted state). Leucine oxidation was also decreased (8.90 +/- 0.76 to 6.52 +/- 0.81 mumol/min, P = 0.025), more so in the fasted than the fed state. These results indicate a significant antiproteolytic endocrine effect for IGF-I in the late-gestation mammalian fetus.
Coping With the Demographic Challenge: Fewer Children and Living Longer

Due to demographic changes, the U.S. Social Security system will face financial challenges in the near future. Declining fertility rates and increasing life expectancies are causing the U.S. population to age. Today 12 percent of the total population is aged 65 or older, but by 2080, it will be 23 percent. At the same time, the working-age population is shrinking from 60 percent today to a projected 54 percent in 2080. Consequently, the Social Security system is experiencing a declining worker-to-beneficiary ratio, which will fall from 3.3 in 2005 to 2.1 in 2040 (the year in which the Social Security trust fund is projected to be exhausted). This presents a significant challenge to policymakers. One policy option that could help keep the Social Security system solvent is to reduce retirement benefits, either by raising the normal retirement age or through life expectancy indexing, to reflect the fact that people are living longer. However, these reductions in benefits have the potential to harm economically vulnerable retirees. Other options, such as progressive price indexing proposals, explicitly protect the retirement benefits of low lifetime earners. Still other options would seek to raise additional revenue for the system. Since individuals will be living longer in retirement, many policymakers believe it is important to encourage older workers to delay retirement so that they can maintain a quality standard of living throughout their retirement. One proposal to encourage continued work would be to increase the early eligibility age for Social Security benefits from age 62 to age 65. This could possibly hurt individuals who need to retire from physically demanding jobs but would ensure that people receive higher benefit amounts once they were able to fully retire. Other proposals that could promote more work at older ages include expanding phased retirement options and reforming pension and defined contribution systems to create incentives to work and save.
Synthesis of the Escherichia coli K‐12 nucleoid‐associated DNA‐binding protein H‐NS is subjected to growth‐phase control and autoregulation

Mutations in the structural gene (hns) for the Escherichia coli nucleoid‐associated DNA‐binding protein H‐NS cause highly pleiotropic effects on gene expression, site‐specific recombination, transposition of phage Mu, the stability of the genetic material and the topological state of the DNA. We have investigated the regulation of hns expression and found that hns transcription is subjected to stationary phase induction and negative autoregulation. A set of hns–lacZ protein and operon fusions was constructed in vitro and integrated in single copy into the attB site of the bacterial genome. Quantification of β‐galactosidase activity along the bacterial growth curve showed that hns expression increases approximately 10‐fold in stationary phase compared with exponentially growing cells. Immunological detection of the H‐NS protein in growing and stationary phase cells supported the genetic data and showed that H‐NS synthesis varies with growth phase. In addition, primer extension experiments demonstrated that the amount of hns mRNA is elevated in stationary phase cultures and that hns transcription is directed by a unique promoter functioning in both log and stationary phase. Disruption of the hns gene by an insertion mutation led to the derepression (approximately fourfold) of the expression of an hns–lacZ operon fusion integrated at the attB site, showing that hns transcription is subjected to negative regulation by its own gene product. Autoregulation of hns expression is particularly pronounced in log phase. Both stationary phase control and autoregulation of hns transcription are associated with a 130 bp fragment that contains the hns promoter. In order to study the interaction of H‐NS with its own regulatory region, we developed an efficient overproduction procedure and a simple purification scheme for H‐NS. DNA gel retardation assays showed that the H‐NS protein can preferentially interact with a restriction fragment carrying the hnspromoter. This restriction fragment showed features of curved DNA as judged by two‐dimensional polyacrylamide gel electrophoresis performed at 4°C and 60°C.
CORONARY ARTERY DISEASE Original Studies Evaluation of the PercuSurge GuardWire Plus Temporary Occlusion and Aspiration System During Primary Angioplasty in Acute Myocardial Infarction

Thirty patients with acute myocardial infarction (AMI) underwent primary angioplasty under distal protection of PercuSurge GuardWire Plus Temporary Occlusion and Aspiration System. Before angioplasty, protection of the distal circulation was achieved with the system, followed by balloon angioplasty and/or stenting and debris aspiration. Technical device success was 100%. Distal occlusion was well tolerated in all patients. Mean total distal occlusion time was 7.3 5.4 min. Macroscopically visible debris was aspirated from 29 cases (96.7%). Postprocedural Thrombolysis in Myocardial Infarction flow grade 3 was achieved in all cases (100%, vs. 16.7% at baseline). Myocardial blush flow grade 3 was achieved in 26 cases (86.7%). Regression of ST segment elevation ≥ 50% was shown in 23 cases (76.7%). No patient developed angiographic evidence of no-reflow or distal embolization. Both angiographic and procedural success were 100%. The system is feasible, safe, and effective for distal protection against embolism during primary angioplasty in AMI. Catheter Cardiovasc Interv 2003;60:443–451. © 2003 Wiley-Liss, Inc.
Effet des ponceaux forestiers sur la distribution de la diversité génétique chez l'omble de fontaine au sein d'un bassin versant boréal.

Consequence directe de l'expansion humaine et des amenagements qui en decoulent, le phenomene de fragmentation des habitats figure aujourd'hui parmi les enjeux majeurs en biologie de la conservation. Les routes constituent l'une des principales sources de fragmentation des habitats aquatiques puisqu'elles engendrent, en milieu riverain, l'installation de nombreuses traverses de cours d'eau. L'objet principal de cette etude etait de mesurer l'effet des barrieres anthropiques liees aux infrastructures de transport (ponceaux) sur la distribution de la diversite genetique chez l'omble de fontaine (Salvelinus fontinalis) et dans un second temps, de le comparer a celui resultant de la presence de barrieres naturelles aux flux de genes (chutes naturelles). Au cours de l'ete 2012, 25 sites ont ete echantillonnees dans un bassin versant boreal fragmente par des chutes naturelles et des ponceaux forestiers. Au total, 996 individus ont ete genotypes a l'aide de 16 marqueurs microsatellites. En tenant compte de l'influence relative de differents facteurs environnementaux, nous avons teste si la presence de chutes naturelles et de ponceaux forestiers resultait en une diminution de la diversite genetique des populations situees en amont de ces barrieres et en une augmentation de la differenciation genetique entre ces dernieres. Par ailleurs, considerant que les ponceaux constituent effectivement un obstacle aux flux geniques, nous avons teste si les caracteristiques physiques de ces structures avaient une influence sur le degre de connectivite genetique entre les localites echantillonnees. Les resultats temoignent d'une differenciation genetique plus importante entre les sites separes par des barrieres (chutes et ponceaux) ainsi que d'une diversite genetique plus faible en amont de ces dernieres. D'apres nos analyses, l'effet des ponceaux sur la distribution de la diversite genetique chez l'omble de fontaine etait legerement plus prononce que celui des chutes naturelles. Par ailleurs, les analyses ont permis de mettre en evidence un effet cumulatif des ponceaux forestiers avec des indices genetiques negativement correles au nombre de ponceaux situees a l'aval (diversite genetique) ou entre (differenciation genetique) les sites echantillonnes. Nos resultats indiquent egalement que la presence d'une chute d'eau a l'extremite aval des ponceaux accentue l'impact de ces structures sur les flux geniques. A notre connaissance cette etude est la premiere a illustrer l'effet des ponceaux forestiers sur la distribution de la diversite genetique chez l'omble de fontaine dans un bassin versant boreal.
A Random Change Point Model for Cognitive Decline in Alzheimer’s Disease and Mild Cognitive Impairment

Background: We present a random change point model to characterize decline in cognition among community-based elderly who developed Alzheimer’s disease (AD) or amnestic mild cognitive impairment (MCI), and to examine how decline varies with age, sex, education, and APOE status. Methods: Using longitudinal cohort data on cognitive function, we fit a piecewise linear trajectory with a random change point that allows different rates of cognitive decline before and after the change point. We estimated the change point that signals the onset of cognitive impairment, and examined the association of risk factors with the location of the change point as well as the rates of decline before and after the change point. Results: Among participants who were dementia free at enrollment and developed incident AD, the change point occurred on average 5.7 years after enrollment and the rate of cognitive decline after the change point nearly quadrupled. Age, education, and APOE status play important but different roles in the timing of the onset of cognitive impairment and in the rates of decline before and after its onset. Results were similar among participants who were cognitively unimpaired at enrollment but later developed amnestic MCI or AD. Conclusions: The random change point model provides a more comprehensive understanding of the relation of risk factors with the onset of cognitive impairment and rates of decline before and after its onset.
Cardiac energetics, cell volumes, sodium fluxes, and membrane permeability: NMR studies of cold ischemia.

Intracellular sodium accumulation, cellular swelling, and energy deficiency are ischemia-associated processes that participate in the transition to irreversible ischemic injury. This study aims to determine the relationship among these parameters in intact rat hearts during global ischemia at 4 degrees C. High-energy phosphates were determined by 31P nuclear magnetic resonance, intracellular sodium accumulation was measured by 23Na spectroscopy with the shift reagent dysprosium triethyl tetraaminohexaacetic acid [Dy(TTHA)3(-)], and cell volumes were measured by 59Co and 1H spectroscopy with use of the extracellular marker Co(CN)3-(6). Intracellular sodium flux rates were 1.53 +/- 0.17, 0.17 +/- 0.05, and 0.30 +/- 0.06 mumol.g dry wt-1.min-1 at 0-1.5, 2-7, and 9-12 h, respectively. Sodium influx resulted in accumulation of the ion: 10% after 4 h, 16% after 10 h, and 29% after 12 h. Water followed sodium into the cells at two constant molar ratios (Na+/H2O): 3.80 +/- 0.15 x 10(-3) during the first 8 h of ischemia and 7.8 x 10(-3) at 8-12 h. Relative to initial intracellular volume, cells swelled by 38% after 8 h and 46% after 12 h; reperfusion reduced cellular swelling to 25 and 36%, respectively. (ABSTRACT TRUNCATED AT 250 WORDS)
Screening of N-ras gene mutations in urothelial cell carcinomas of the urinary bladder in the Kashmiri population.

BACKGROUND AND AIMS The objective of this study was to assess the frequency of specific-point mutations in N-ras of the RAS gene family in a group of Kashmiri patients with bladder cancer and to observe any association with clinicopathological parameters. METHODS Paired tumor and normal tissue specimens of 55 consecutive patients with urothelial cell carcinoma were screened and DNA was extracted for detection of N-ras activating mutations in exons 1 and 2. In addition, blood was also collected from all the cases to rule out any germ line mutation. RESULTS Specific point mutations of activated N-ras were detected in 9% (5 of 55) of the bladder cancer patients, all being missense. The base substitutions identified included three transversions (two G toT and one A to T) and two transitions ( A-G). Sixty % of the mutations were detected in codon 61 and 40% in codon 12. No significant correlations were found between the mutations and clinical features. CONCLUSION Although N-ras gene mutation might be one of the mechanisms underlying oncogenesis of urothelial cancer, it seems to be a relatively rare event in Kasmiris, pointing to involvement of different etiological factors in the induction of bladder tumor in this population.
Genes involved in the regulation of beta-lactamase production in enterococci and staphylococci

In enterococci, the structural gene for beta-lactamase (blaZ) is identical to blaZ from Staphylococcus aureus. However, in the enterococci studied to date, beta-lactamase is produced constitutively, whereas in staphylococci it is often inducible. Recent reports have revealed the presence of two adjacent genes upstream of the staphylococcal blaZ thought to be the antirepressor (blaR1) and repressor (blaI) genes. In the present study, beta-lactamase expression mutants of the staphylococcal beta-lactamase plasmid pI524 were generated by transposon mutagenesis with the transposon Tn917. Tn917 insertions upstream of blaZ in either blaR1 or blaI resulted in constitutive beta-lactamase production, indicating that the repressor function is lost with insertion of Tn917 into either gene. This finding supports the concept that the staphylococcal beta-lactamase regulatory genes are encoded on a polycistronic mRNA. The corresponding region upstream of the enterococcal blaZ from Enterococcus faecalis HH22 was sequenced and compared with the staphylococcal blaR1 sequence. The two sequences were identical for 893 nucleotides, and then the sequences diverged completely. Therefore, in strain HH22, only 51% of the putative antirepressor gene is present and the repressor gene is also absent. In conclusion, constitutive beta-lactamase production in HH22 appears to be due to a lack of the regulatory genes blaR1 and blaI which regulate expression of blaZ in staphylococci.
IGF2/ApaI polymorphism associated with birth weight in children of the region of Petrolina–PE, Brazil

Insulin-like growth factor 2 (IGF2) gene has an important role in fetal growth. It was investigated association of the IGF2/ApaI polymorphism with low birth weight and normal birth weight (as control) in children attended in Hospital Dom Malan Petrolina, PE-Brazil. The genotype frequencies did not differ statistically between low birth weight (AA = 16.22%, AG = 43.24%, GG = 40.54%) and control (AA = 20% AG = 35%, GG= 45% groups) and the allele frequencies were not significantly different (p > 0.05). The observed genotype frequencies in both groups did not deviate significantly from Hardy–Weinberg equilibrium. Then, no significant correlation was found for this polymorphism in the population studied.