Parallel gene synthesis in a microfluidic device

The ability to synthesize custom de novo DNA constructs rapidly, accurately and inexpensively is highly desired by researchers, as synthetic genes and longer DNA constructs are enabling to numerous powerful applications in both traditional molecular biology and the emerging field of synthetic biology. However, the current cost of de novo synthesis—driven largely by reagent and handling costs—is a significant barrier to the widespread availability of such technology. In this work, we demonstrate, to our knowledge, the first gene synthesis in a microfluidic environment. The use of microfluidic technology greatly reduces reaction volumes and the corresponding reagent and handling costs. Additionally, microfluidic technology enables large numbers of complex reactions to be performed in parallel. Here, we report the fabrication of a multi-chamber microfluidic device and its use in carrying out the syntheses of several DNA constructs. Genes up to 1 kb in length were synthesized in parallel at minute starting oligonucleotide concentrations (10–25 nM) in four 500 nl reactors. Such volumes are one to two orders of magnitude lower than those utilized in conventional gene synthesis. The identity of all target genes was verified by sequencing, and the resultant error rate was determined to be 1 per 560 bases.Massachusetts Institute of Technology. Center for Bits and AtomsNational Science Foundation (U.S.) (CBA grant CCR-0122419

A questionnaire elicitation of surgeons' belief about learning within a surgical trial

PMID: 23145113 [PubMed - indexed for MEDLINE] PMCID: PMC3493499 Free PMC ArticlePeer reviewedPublisher PD

First-trimester or second-trimester screening, or both, for Down's syndrome

BACKGROUND: It is uncertain how best to screen pregnant women for the presence of fetal Down's syndrome: to perform first-trimester screening, to perform second-trimester screening, or to use strategies incorporating measurements in both trimesters.METHODS: Women with singleton pregnancies underwent first-trimester combined screening (measurement of nuchal translucency, pregnancy-associated plasma protein A [PAPP-A], and the free beta subunit of human chorionic gonadotropin at 10 weeks 3 days through 13 weeks 6 days of gestation) and second-trimester quadruple screening (measurement of alpha-fetoprotein, total human chorionic gonadotropin, unconjugated estriol, and inhibin A at 15 through 18 weeks of gestation). We compared the results of stepwise sequential screening (risk results provided after each test), fully integrated screening (single risk result provided), and serum integrated screening (identical to fully integrated screening, but without nuchal translucency).RESULTS: First-trimester screening was performed in 38,167 patients; 117 had a fetus with Down's syndrome. At a 5 percent false positive rate, the rates of detection of Down's syndrome were as follows: with first-trimester combined screening, 87 percent, 85 percent, and 82 percent for measurements performed at 11, 12, and 13 weeks, respectively; with second-trimester quadruple screening, 81 percent; with stepwise sequential screening, 95 percent; with serum integrated screening, 88 percent; and with fully integrated screening with first-trimester measurements performed at 11 weeks, 96 percent. Paired comparisons found significant differences between the tests, except for the comparison between serum integrated screening and combined screening.CONCLUSIONS: First-trimester combined screening at 11 weeks of gestation is better than second-trimester quadruple screening but at 13 weeks has results similar to second-trimester quadruple screening. Both stepwise sequential screening and fully integrated screening have high rates of detection of Down's syndrome, with low false positive rates

The Sec1/Munc18 protein Vps45 regulates cellular levels of its SNARE binding partners Tlg2 and Snc2 in Saccharomyces cerevisiae

Intracellular membrane trafficking pathways must be tightly regulated to ensure proper functioning of all eukaryotic cells. Central to membrane trafficking is the formation of specific SNARE (soluble N-ethylmeleimide-sensitive factor attachment protein receptor) complexes between proteins on opposing lipid bilayers. The Sec1/Munc18 (SM) family of proteins play an essential role in SNARE-mediated membrane fusion, and like the SNAREs are conserved through evolution from yeast to humans. The SM protein Vps45 is required for the formation of yeast endosomal SNARE complexes and is thus essential for traffic through the endosomal system. Here we report that, in addition to its role in regulating SNARE complex assembly, Vps45 regulates cellular levels of its SNARE binding partners: the syntaxin Tlg2 and the v-SNARE Snc2: Cells lacking Vps45 have reduced cellular levels of Tlg2 and Snc2; and elevation of Vps45 levels results in concomitant increases in the levels of both Tlg2 and Snc2. As well as regulating traffic through the endosomal system, the Snc v-SNAREs are also required for exocytosis. Unlike most vps mutants, cells lacking Vps45 display multiple growth phenotypes. Here we report that these can be reversed by selectively restoring Snc2 levels in vps45 mutant cells. Our data indicate that as well as functioning as part of the machinery that controls SNARE complex assembly, Vps45 also plays a key role in determining the levels of its cognate SNARE proteins; another key factor in regulation of membrane traffic

A substantial prehistoric European ancestry amongst Ashkenazi maternal lineages

The origins of Ashkenazi Jews remain highly controversial. Like Judaism, mitochondrial DNA is passed along the maternal line. Its variation in the Ashkenazim is highly distinctive, with four major and numerous minor founders. However, due to their rarity in the general population, these founders have been difficult to trace to a source. Here we show that all four major founders, similar to 40% of Ashkenazi mtDNA variation, have ancestry in prehistoric Europe, rather than the Near East or Caucasus. Furthermore, most of the remaining minor founders share a similar deep European ancestry. Thus the great majority of Ashkenazi maternal lineages were not brought from the Levant, as commonly supposed, nor recruited in the Caucasus, as sometimes suggested, but assimilated within Europe. These results point to a significant role for the conversion of women in the formation of Ashkenazi communities, and provide the foundation for a detailed reconstruction of Ashkenazi genealogical history

Concert recording 2014-04-08

[Track 01]. Madama Butterfly. Un bel di vedremo / Glacomo Puccini -- [Track 02]. Hello again. Tom / Michael John LaCiusa -- [Track 03]. Mein schoner stern! (my lovely star) / Robert Schumann -- [Track 04]. Into the night / Robert Schumann -- [Track 05]. Per la Gloria / Giovanni B. Bonocirii -- [Track 06]. Bonjour, Suzon! / Leo Delibes -- [Track 07]. Die Winterreise. Erstarrung (numbness) / Franz Schubert -- [Track 08]. West Side Story. Something\u27s coming / Leonard Bernstein -- [Track 09]. Un ballo in maschera. Saper vorreste / Giuseppe Verdi -- [Track 10]. O del mio amato ben / Stefeno Donaudy -- [Track 11]. O del mio dolce ardor / Christoph W. von Gluck -- [Track 12]. My fair lady. I could have danced all night / Loewe & Lerner -- [Track 13]. Vergebliches standchen (The vain suit) / Johannes Brahms

Pharmacoepidemiology and the Australian regional prevalence of multiple sclerosis

Background: Over some 50 years, field surveys have shown that the prevalence of multiple sclerosis (MS) increases with increasing distance from the equator in both the northern and the southern hemispheres. Such a latitudinal gradient has been found in field surveys of MS prevalence carried out at different times in various local regions of Australia

Concert recording 2013-04-01

[Track 01]. What can we poor females do / Henry Purcell -- [Track 02]. The telephone. Lucy\u27s aria / Gian Carlo Menotti -- [Track 03]. Every time I feel de spirit / arranged by Harry T. Burleigh -- [Track 04]. Carmen. L\u27amour est un oiseau rebelled (Habanera) / Georges Bizet -- [Track 05]. O del mio dolce ardor / Chistoph W. von Gluck -- [Track 06]. Semele. Where e\u27er you walk / George F. Handel -- [Track 07]. Go lovely Rose / Roger Quilter -- [Track 08]. Man is for the Woman made / Henry Purcell -- [Track 09]. Les Contes D\u27Hoffman. Elle a fui, la tourterelle! / Jacques Offenbach -- [Track 10]. Der Schauspieldirektor. Bester Yungling / Wolfgang A. Mozart -- [Track 11]. Der Erlkonnig / Franz Schubert -- [Track 12]. Faust. Avant de quitter ce lieux / Charles Gounod -- [Track 13]. Give a man a horse he can ride / Geoffrey O\u27Hara -- [Track 14]. Icis-bas / Gabriel Faure -- [Track 15]. The negro speaks of rivers / Margaret Bonds -- [Track 16]. Romeo et Juliette. Ah! Je veux vivre / Charles Gounod -- [Track 17]. The 25th annual Putnam County spelling bee. I speak six languages / Feldman ; Finn

Diffuse small bowel thickening in aids patient - a case report

<p>Abstract</p> <p>Background</p> <p>Diarrhea is common in HIV/AIDS patients, caused by both classic enteric pathogens and different opportunistic agents. <it>Infection with these different pathogens may lead to similar radiological findings, thus causing diagnostic confusion</it>.</p> <p>Case presentation</p> <p>A 30-yr-old female with AIDS presented with chronic diarrhea of 4 months duration. She had diffuse small bowel thickening present on CT scan of her abdomen, with stool examination showing no parasites. She was erroneously diagnosed as abdominal tuberculosis and given antituberculosis drugs with which she showed no improvement. Repeat stool examination later at a specialized laboratory revealed <it>Cryptosporidium parvum </it>infection.</p> <p>The patient was given an extended course of nitazoxanide treatment, as her stool examination was positive for <it>Cryptosporidium parvum </it>even after 2 weeks of drug consumption. Parasite clearance was documented after 10 weeks of treatment. Interestingly, the bowel thickening reversed with parasitological clearance.</p> <p>Conclusions</p> <p><it>Cryptosporidium parvum </it>may lead to small bowel thickening in AIDS patients. This small bowel thickening may reverse following parasitological clearance.</p