An Essay on Evolution: Evolution and The Origin of Life are Separate and Distinct Concepts

Two years ago on a Saturday morning, I was asked quite pointedly by two friends how I could be both spiritual and a scientist. My questioning friends felt that these qualities were incompatible. It turned out their church taught that scientists were ‘the enemy’ because scientists believe in evolution. Since that time, Letters to the Editor regarding evolution have attracted my attention. Many of the published letters stated that the author did not believe in evolution, and argued in support of his/her position that God had created life. The authors thoroughly confuse two concepts which are separate and distinct: Evolution and the Origin of Lif

How Science Makes America Great

The proposed Federal Budget cuts funding for NIH, NSF, and CDC by 16% each and for the EPA by a whopping 31%. Ouch! The situation seems ironic because of President Trump’s slogan “Make America great again!”, which I agree with wholeheartedly. In addition to being a scientist, I also love history (especially military history) and science is at the top of my list of what has made the United States great. ... Why do we do it? I’m in science because it is rewarding. It is invigorating to discover how nature works. Scientists may act individually and in relative obscurity, but collectively we really do benefit society. Topics with * indicate the contributions of my grandfather, my father, and myself. I view science as a family value, with a little pioneer spirit

How Science Makes America Great

The proposed Federal Budget cuts funding for NIH, NSF, and CDC by 16% each and for the EPA by a whopping 31%. Ouch! The situation seems ironic because of President Trump’s slogan “Make America great again!”, which I agree with wholeheartedly. In addition to being a scientist, I also love history (especially military history) and science is at the top of my list of what has made the United States great. ... Why do we do it? I’m in science because it is rewarding. It is invigorating to discover how nature works. Scientists may act individually and in relative obscurity, but collectively we really do benefit society. Topics with * indicate the contributions of my grandfather, my father, and myself. I view science as a family value, with a little pioneer spirit

Purification of Poly-3-Hydroxybutyrate by Density Gradient Centrifugation in Sodium Bromide

Fractionation of fully sporulated cultures of Bacillus thuringiensis by density gradient centrifugation in NaBr produced two bands which were identified as poly- β -hydroxybutyrate. This technique generated high yields of membranebound and unbound granules of exceptional purity and degree of polymerization

The \u3ci\u3eBacillus thuringiensis\u3c/i\u3e Insecticidal Toxin Binds Biotin-Containing Proteins

Brush border membrane vesicles from larvae of the tobacco hornworm, Manduca sexta, contain protein bands of 85 and 120 kDa which react directly with streptavidin conjugated to alkaline phosphatase. The binding could be prevented either by including 10 μM biotin in the reaction mixture or by prior incubation of the brush border membrane vesicles with an activated 60- to 65-kDa toxin from Bacillus thuringiensis HD-73. The ability of B. thuringiensis toxins to recognize biotin-containing proteins was confirmed by their binding to pyruvate carboxylase, a biotin-containing enzyme, as well as to biotinylated ovalbumin and biotinylated bovine serum albumin but not to their nonbiotinylated counterparts. Activated HD-73 toxin also inhibited the enzymatic activity of pyruvate carboxylase. The biotin binding site is likely contained in domain III of the toxin. Two highly conserved regions within domain III are similar in sequence to the biotin binding sites of avidin, streptavidin, and a biotin-specific monoclonal antibody. In particular, block 4 of the B. thuringiensis toxin contains the YAS biotin-specific motif. On the basis of its N-terminal amino acid sequence, the 120-kDa biotin-containing protein is totally distinct from the 120-kDa aminopeptidase N reported to be a receptor for Cry1Ac toxin

The \u3ci\u3eBacillus thuringiensis\u3c/i\u3e Insecticidal Toxin Binds Biotin-Containing Proteins

Brush border membrane vesicles from larvae of the tobacco hornworm, Manduca sexta, contain protein bands of 85 and 120 kDa which react directly with streptavidin conjugated to alkaline phosphatase. The binding could be prevented either by including 10 μM biotin in the reaction mixture or by prior incubation of the brush border membrane vesicles with an activated 60- to 65-kDa toxin from Bacillus thuringiensis HD-73. The ability of B. thuringiensis toxins to recognize biotin-containing proteins was confirmed by their binding to pyruvate carboxylase, a biotin-containing enzyme, as well as to biotinylated ovalbumin and biotinylated bovine serum albumin but not to their nonbiotinylated counterparts. Activated HD-73 toxin also inhibited the enzymatic activity of pyruvate carboxylase. The biotin binding site is likely contained in domain III of the toxin. Two highly conserved regions within domain III are similar in sequence to the biotin binding sites of avidin, streptavidin, and a biotin-specific monoclonal antibody. In particular, block 4 of the B. thuringiensis toxin contains the YAS biotin-specific motif. On the basis of its N-terminal amino acid sequence, the 120-kDa biotin-containing protein is totally distinct from the 120-kDa aminopeptidase N reported to be a receptor for Cry1Ac toxin

Quorum sensing in \u3ci\u3eCandida albicans\u3c/i\u3e: farnesol versus farnesoic acid

Candida albicans is a clinically important dimorphic fungus that exhibits either a budding yeast or a mycelial-hyphal or pseudohyphal growth, depending on environmental conditions. The yeast-to-mycelia morphologic transition, which is generally regarded as an important virulence determinant, depends on the inoculum size of liquid cultures. The yeast form is favored when cultures are inoculated at \u3e 106 cells∙mL–1, whereas the mycelial form is favored at inoculum densities \u3c 106∙mL–1. Farnesoic acid (FA) and farnesol (FOH) are two related sesquiterpene quorum- sensing molecules that, upon accumulation, prevent the yeast-to-mycelial conversion. Oh et al. showed that C. albicans strain ATCC 10231 excretes FA, while Hornby et al. showed that C. albicans A72 and SC5314 excrete FOH. Subsequent work indicated that 10231 was the only isolate of C. albicans that fails to produce detectable FOH. Moreover, when tested on C. albicans A72, FA had only 3.2% of the hyphal-inhibitory activity relative to FOH. These observations raised two questions: 1., Do FOH and FA block mycelial development via the same molecular mechanism; and 2., What is the biochemical or physiologic difference in strain 10231 that underlies excretion of FA and not FOH? Do farnesol and farnesoic acid share a common mechanism of action? An apparent paradox in the regulation of hyphal morphogenesis by CaPho81p Why does C. albicans strain 10231 secrete farnesoic acid, while other C. albicans strains secrete farnesol

Microbiology of Oil Fly Larvae

One animal beautifully adapted to the viscous asphalt of the La Brea tar pits is the oil fly Helaeomyia petrolei (Syn. Psilopa). As a normal part of its carnivorous existence the oil fly larval guts are filled with tar, with no adverse effects. Surface sterilized larvae 5 contained ca. 2 x 10 heterotrophic bacteria per larva. These bacteria have been identified as a mixture of enteric bacteria, most commonly Providencia rettgeri, and Acinetobacter spp. These bacteria were clearly growing because their numbers in the larval guts were 100 to 1,000 times greater than in free oil/asphalt. There is no evidence yet that these bacteria can degrade the complex aromatic hydrocarbons of the tar/asphalt. However, the bacteria isolated are highly solvent tolerant and they remain a potential source of hydrocarbon/solvent tolerant enzymes. Likely of greatest evolutionary interest, these bacteria were naturally resistant to 9 of 23 common antibiotics tested. This finding suggests that the oil fly bacteria have an active efflux pump for aromatic hydrocarbons, due to the constant selective pressure of La Brea’s solvent-rich environment. We suggest that the oil fly bacteria and their genes for solvent tolerance may provide a microbial reservoir for antibiotic resistance genes

Enhanced Production of Farnesol by \u3ci\u3eCandida albicans\u3c/i\u3e Treated with Four Azoles

The dimorphic fungus Candida albicans excretes farnesol, which is produced enzymatically from the sterol biosynthetic intermediate farnesyl pyrophosphate. Inhibition of C. albicans by four azole antifungals, fluconazole, ketoconazole, miconazole, and clotrimazole, caused elevated farnesol production (10- to 45-fold). Furthermore, farnesol production occurs in both laboratory strains and clinical isolates (J. M. Hornby et al., Appl. Environ. Microbiol. 67:2982-2992, 2001) of C. albicans

Eight Gram-negative bacteria are 10,000 times more sensitive to cationic detergents than to anionic detergents

In liquid culture, eight typical Gram-negative bacteria were ca. 10,000-fold more sensitive to cationic detergents than to the anionic detergent sodium dodecyl sulfate. Cetyltrimethylammonium bromide (CTAB) was inhibitory at concentrations ranging from 0.0006% to 0.01%. Four pseudomonads able to form biofilms were ca. 1000-fold more resistant to CTAB on Luria–Bertani agar plates than they were in liquid culture. A lasI mutant of Pseudomonas aeruginosa was only able to tolerate 0.1% CTAB on Luria–Bertani agar plates but could tolerate 5% CTAB when supplemented with homoserine lactone containing culture supernatants. En culture liquide, huit bactéries Gram négatif typiques étaient ca. 10,000 fois plus sensible aux détergents cationiques qu\u27au détergent anionique dodécyl sulfate de sodium. Le bromure de cétyltriméthylammonium (CTAB) était inhibiteur à des concentrations allant de 0,0006% à 0,01%. Quatre pseudomonades capables de former des biofilms étaient ca. 1000 fois plus résistant au CTAB sur des plaques de gélose Luria – Bertani qu\u27en culture liquide. Un mutant lasI de Pseudomonas aeruginosa ne pouvait tolérer que 0,1% de CTAB sur des plaques de gélose Luria-Bertani, mais pouvait tolérer 5% de CTAB lorsqu\u27il était complété par des surnageants de culture contenant de l\u27homosérine lactone