Detoxification of polycyclic aromatic hydrocarbons by fungi

Summary The polycyclic aromatic hydrocarbons (PAHs) are a group of hazardous environmental pollutants, many of which are acutely toxic, mutagenic, or carcinogenic. A diverse group of fungi, includingAspergillus ochraceus, Cunninghamella elegans, Phanerochaete chrysosporium, Saccharomyces cerevisiae, andSyncephalastrum racemosum, have the ability to oxidize PAHs. The PAHs anthracene, benz[a]anthracene, benzo[a]pyrene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene, as well as several methyl-, nitro-, and fluoro-substituted PAHs, are metabolized by one or more of these fungi. Unsubstituted PAHs are oxidized initially to arene oxides,trans-dihydrodiols, phenols, quinones, and tetralones. Phenols andtrans-dihydrodiols may be further metabolized, and thus detoxified, by conjugation with sulfate, glucuronic acid, glucose, or xylose. Although dihydrodiol epoxides and other mutagenic and carcinogenic compounds have been detected as minor fungal metabolites of a few PAHs, most transformations performed by fungi reduce the mutagenicity and thus detoxify the PAHs.     

Reductions of neural activities to upper airway muscles after elevations in static lung volume.

We evaluated the hypothesis that the tonic discharge of pulmonary stretch receptors significantly influences the respiratory-modulated activities of cranial nerves. Decerebrate and paralyzed cats were ventilated with a servo-respirator, which produced changes in lung volume in parallel with integrated phrenic activity. Activities of the facial, hypoglossal, and recurrent laryngeal nerves and nerves to the thyroarytenoid muscle and triangularis sterni were recorded. After a stereotyped pattern of lung inflation, tracheal pressure was held at 1, 2, 4, or 6 cmH2O during the subsequent ventilatory cycle. Increases in tracheal pressure caused progressive reductions in both inspiratory and expiratory cranial nerve activities and progressive elevations in triangularis sterni discharge; peak levels of phrenic activity declined modestly. Similar changes were observed in normocapnia and hypercapnia. We conclude that the tonic discharge of pulmonary stretch receptors is an important determinant of the presence and magnitude of respiratory-modulated cranial nerve activity. This reflex mechanism may maintain upper airway patency and also regulate expiratory airflow.     

HOST EFFECTS ON FERTILITY AND REPRODUCTIVE SUCCESS OF DENDROCTONUS PONDEROSAE HOPKINS (COLEOPTERA: SCOLYTIDAE)

Mountain pine beetles from lodgepole and limber pine in western Canada were crossbred. We compared data about reproductive success and fecundity of parents as well as development, mortality, and fertility of their progeny to determine whether there was reproductive isolation among beetle populations in these hosts. Three factors, directly or indirectly related to the host, influenced reproductive performance of parents (reproductive success, egg gallery length, fecundity, and number of eggs laid per centimeter of gallery) as well as the mortality, dry weight, and fat content of the progeny: (1) the host species in which progeny were reared, (2) the host species in which the female parent was reared, and (3) whether both parents originated from the same or different host species. Limber pine appears to be a better host for Dendroctonus ponderosae reproduction and survival than lodgepole pine. Nonetheless, beetles reared from lodgepole and limber pine can reproduce in either host and will mate with each other. Progeny of all crosses were fertile. Thus, there is no apparent barrier to prevent beetles from the two host species from interbreeding in the field.     

Urokinase and tissue type plasminogen activators in human keratinocyte culture

Using immunocytochemical and biochemical techniques, we have demonstrated that cultured human epidermal keratinocytes contain both urokinase and tissue type plasminogen activators. In subconfluent colonies the distribution of the two enzymes differed. Tissue type plasminogen activator (tPA) was distributed evenly throughout the colony, while, as we have demonstrated previously, urokinase type plasminogen activator (uPA) was preferentially localized at the migrating edges of the colony. Using zymographic analyses, both tPA and uPA activities were detected in cell extracts. Depending on the procedure used to prepare cell extracts, tPA was detected either as free enzyme or in complex with PA inhibitor type 1. PA inhibitor type 1 was deposited onto the extracellular matrix of the keratinocyte cultures and formed a complex with cell-associated tPA when cells and matrix were extracted together. The most differentiated keratinocytes in the culture, which were spontaneously shed from the culture surface, also contained both tPA and uPA. However, these spontaneously shed cells had a higher ratio of tPA:uPA than did the less differentiated cells from the same culture. In conjunction with our previous studies, these results demonstrate the complex nature of the plasminogen activator system, including enzymes and inhibitors, that is present in human keratinocytes. In addition, our data suggest that the relative amounts of uPA and tPA in epidermal cells vary with differentiation state.     

Predominance of picoplankton and nanoplankton in eutrophic Calder Lake

A study was conducted to examine factors regulating the biomass of algal picoplankton in Calder Lake, a small eutrophic lake in southern New York state. A particular focus was a current paradigm which suggests that larger cells may dominate in nutrient-rich waters, while smaller cells may predominate only in oligotrophic waters. Over two years, phytoplankton biomass consisted predominantly (74% on average) of very small organisms; nanoplankton (<20 to 2 µm: 39%) and picoplankton (<2 µm to 0.2 µm: 35%), despite the presence of surface blooms of colonial cyanobacteria (Microcystis aeruginosa, Anabaena limnetica), and dense metalimnetic populations of the dinoflagellate Ceratium hirundinella. This dimictic system is characterized by relatively high levels of total P (max = 85, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\] = 9.7 µg P/L), inorganic P (max = 26, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\] = 4.5 µg P/L), and total inorganic N (max = 285, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGabmiEayaara% aaaa!3702!\[\bar x\] = 85 µg P/L), but larger forms were rarely the most abundant. Unlike some marine systems, greater abundance of algal picoplankton was not associated with deeper strata (low light), or warmer temperatures. Data suggest that midsummer nutrient limitation, especially P-limitation, favors the development of pico- and nanoplankton in the limnetic zone of eutrophic lakes.     

Territory size and distribution of newly-emerged Atlantic salmon (Salmo salar)

Newly emerged Atlantic salmon (Salmo salar) were observed from May to August 1981 at six isolated redds in Washington County, Maine, USA. Territorial size and distribution were measured. At the end of the emergence period (12 to 28 May), fish maintained positions (stations) at redds where water velocity did not exceed 52 cm s^–1 By 12 June, most salmon (80–96%) had moved off the redds of origin and had established territories 1 to 5 m from the redd. The area defended increased substantially after mid-June, but territorial aggression diminished by 15 July, and the fry dispersed downstream. All fish observed were territorial, and the percentage of time during which stations were held decreased from 89 in mid-May to as low as 40% in mid-June.Cooperators are the Maine Department of Inland Fisheries and Wildlife, University of Maine, U.S. Fish and Wildlife Service, and the Wildlife Management Institute     

Proton NMR studies of transforming and nontransforming H-ras p21 mutants

One- and two-dimensional nuclear magnetic resonance spectroscopy (1D and 2D NMR) and site-directed mutagenesis were used to study the influence of mutations on the conformation of the H-ras oncogene product p21. No severe structural differences between the different mutants, whether they were transforming or nontransforming, could be detected. Initially, selective incorporation of 3,5-deuterated tyrosyl residues into p21 and 2D NMR were used to identify the resonances representing the spin systems of the imidazole rings of the three histidyl residues in the protein, of six of the nine tyrosyl rings, and of four of the five phenylalanyl rings. The spin systems of the phenyl rings of Phe28, Phe78, and Phe82 could be assigned by using mutant proteins, since no severe structure-induced spectral changes in the aromatic part of the spectra of the mutant proteins were detected. Sequence-specific assignments of the histidine imidazole resonances could be obtained by comparison of the distance information obtained by nuclear Overhauser enhancement spectroscopy (NOESY) experiments with the crystal structure. The change in the chemical shift values of the Hl' proton and the alpha-phosphate of the bound GDP in the NMR spectra of the p21(F28L) mutant and the 28-fold increase in the GDP dissociation rate constants of this mutant suggest a strong interaction between Phe28 and the p21-bound nucleotide. In solution, the p21-bound GDP.Mg2+ has an anti conformation, and the phenyl ring of Phe28 is close to the ribose of the bound GDP.Mg2+.     

Neotypification of Amellus villosus,the identity of a bradbury collection,and typification of some other goldenasters (Compositae: Astereae)

Nomenclatural problems involving closely related North American goldenasters are resolved. No original type material (a collection by John Bradbury) is known forAmellus villosus Pursh, which is the basionym for the taxon referred to asChrysopsis villosa and more recently asHeterotheca villosa. The species is the first-described taxon inHeterotheca sect.Phyllotheca. A collection by Bradbury (LIV) was found to belong inH. camporum and does not match Pursh's protologue. A neotype (PH) was selected from collections by Thomas Nuttall. A problem in the typification of the second oldest taxon in sect.Phyllotheca was encountered. The specimen filed at K as the type ofDiplopappus hispidus Hook. was not the specimen cited in the protologue. A lectotype has been designated from collections by Richardson at BM. Other taxa placed in synonymy are also typified.     

A locus for familial hypertrophic cardiomyopathy is closely linked to the cardiac myosin heavy chain genes, CRI-L436, and CRI-L329 on chromosome 14 at q11-q12

We report that a gene responsible for familial hypertrophic cardiomyopathy (HC) is closely linked to the cardiac alpha and beta myosin heavy chain (MHC) genes on chromosome 14q11. We have recently shown that probe CRI-L436, derived from the anonymous DNA locus D14S26, detects a polymorphic restriction fragment that segregates with familial HC in affected members of a large Canadian family. Using chromosomal in situ hybridization, we have mapped CRI-L436 to chromosome 14 at q11-q12. Because the cardiac MHC genes also map to this chromosomal band, we have determined the genetic distances between the cardiac beta MHC gene, D14S26, and the familial HC locus. Data presented here show that these three loci are linked within 5 centimorgans on chromosome 14 at q11-q12. The possibility that defects in either the cardiac alpha or beta MHC genes are responsible for familial HC is discussed.     

Determination of 4-hydroxyproline in collagen by gas chromatography/mass spectrometry

Derivatization of 4-hydroxyproline (Hyp) in collagen using trifluoroacetylation and methanol esterification produces two derivatives when analyzed by gas chromatography/mass spectrometry (GC/MS). The diacyl derivative N,O-bis(trifluoroacetyl)-4-hydroxy-L-proline methyl ester (N,O-TFA-Hyp) formed in this manner has a shorter retention time and different fragmentation pattern by GC/MS as compared to the slower eluting monoacetylated species N-trifluoroacetyl-4-hydroxy-L-proline methyl ester (N-TFA-Hyp). By selected ion monitoring of the appropriate ions of either N,O-TFA-Hyp (m/z 164, 278) or N-TFA-Hyp (m/z 164, 182) efficient quantitation of Hyp in collagen is possible within the broad range of 5-1000 ng with a lower limit of detection of 0.5 ng per injection. Measurement of 18O2 incorporation into collagen is possible by selected ion monitoring of the m/z 182 ion formed only from the monoacetylated derivative, N-TFA-Hyp, produced by methanol solvolysis of the N,O-TFA-Hyp derivative, as proposed herein.