Fast atom bombardment combined with tandem mass spectrometry for the determination of nucleosides

The positive and negative ion fast atom bombardment (FAB) mass spectra and fast atom bombardment collisionally activated decomposition (CAD) spectra of a series of nucleosides and two dinucleotides are reported. The nucleosides studied are substituted forms of guanosine, adenosine, nebularine, tubercidin, uridine, and related pyrimidines. The FAB and CAD data both contain similar information. The CAD spectra are found to provide some structural information not found in the FAB mass spectra. Tandem mass spectrometry also allows emphasis to be put on weak fragments which are either not observed in the FAB mass spectrum or are lost in the matrix ion signals.     

Contribution of α- -galactopyranosyl end groups to attachment of highly and low metastatic murine fibrosarcoma cells to various substrates

There are much greater numbers of cell surface terminal, non-reducing α- -galactorpyranosyl groups in highly malignant (metastatic) cells than are found in low malignant cells derived from the same murine fibrosarcoma. We have examined the contribution of these residues to attachment of the cells to various collagens and to plastic. Removal of these carbohydrate groups with α-galactosidase or blocking them with lectins from Griffonia simplicifolia seeds or with anti-blood group B antiserum all dramatically inhibited the attachment of both the highly malignant and the low malignant cells. Following removal with the enzyme, the α- -galactopyranosyl end groups were rapidly resynthesized. This resynthesis was inhibited by tunicamycin, an inhibitor of de novo glycoprotein synthesis. This antibiotic also impaired cell attachment and, when used in addition to treatment with α-galactosidase, it inhibited cell attachment more than did treatment with the enzyme alone. The effects of all treatments on cell attachment were greater for the highly malignant than for the low malignant cells. With the latter cells, inhibition by lectin was seen only in the absence of serum, whereas the adhesion of highly malignant cells was affected in both the presence and the absence of serum. On their surface membrane the highly malignant cells express much more than do the low malignant cells of a glycoprotein that cross-reacts immunologically with laminin. The basement membrane glycoprotein laminin promotes cell attachment to collagen, and both glycoproteins contain terminal, non-reducing α- -galactopyranosyl groups. Attachment of cells is a requirement for the formation of a metastasis, and thus the laminin-like molecule and the α- -galactopyranosyl end groups (whether on the laminin-related moiety or on other cell surface molecules) may both be important for expression of the most malignant phenotype.     

Regulation of human leukocyte microsomal hydroxymethylglutaryl-CoA reductase activity by a phosphorylation and dephosphorylation mechanism

The activity of microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.34), obtained from cultured human IM-9 lymphoid cells or freshly isolated human peripheral blood leukocytes, is modulated by a phosphorylation/dephosphorylation mechanism. Addition of MgATP + ADP to IM-9 cell microsomal reductase leads to a time-dependent loss of enzyme activity. Inactivated reductase is reactivated by rat liver reductase phosphatase. Kinase-dependent IM-9 cell microsomal reductase, prepared by heating IM-9 microsomes for 15 min at 50°C, is inactivated in the presence of MgATP and ADP only after addition of cytosolic reductase kinase from either IM-9 cells, freshly isolated leukocytes or rat liver. Inactivation is time-dependent and dependent on the cytosolic protein concentration. Inactivated reductase is reactivated by rat liver reductase phosphatase. For cultured IM-9 cells and freshly isolated leukocytes incubated with culture medium for 2 h, the ratios of active (unphosphorylated) to total (phosphorylated + unphosphorylated) reductase activity are 0.22 and 0.43, respectively. Thus, in addition to its regulation by changes in the amount of total enzyme protein, human leukocyte reductase activity is also modulated by a phosphorylation/dephosphorylation mechanism.     

Organogenesis in callus derived from stem and leaf tissues of apple and cherry rootstocks

Callus formation from stem internodes of the apple rootstocks M.9, M.25, M.26, M.27 and the cherry rootstock Colt, and from pith of Nicotiana tabacum cv. Wisconsin 38 was initiated on 4 -naphthaleneacetic acid (NAA)-based media (2.0–10.0 mg1^-1). Transfer of callus to corresponding media lacking NAA allowed regeneration of shoots from callus of M.25, M.27, Colt and tobacco but not of M.9 and M.26. With M.25 phloroglucinol (PG) depressed regeneration from 30 to 10% and no regeneration was observed in cultures grown in the presence of casein hydrolysate (CH) and glutathione (GSH).Organogenesis was also obtained from leaf discs of M.27 employing 6-benzyl-aminopurine (BAP) at 5.0mg 1^-1 and 2,4-dichlorophenoxy acetic acid (2,4-D) at 0.1 mg1^-1. The regenerated shoots have been multiplied and rooted.Organogenesis also occurred in M.26 from small (1–2mm), green, compact embryoid-like structures derived from stem and leaf surfaces of excised axillary shoots. These structures differentiated into shoots at a low frequency (< 1%) on media containing BAP (1.0mg1^-1) and indole-3-butyric acid (IBA) (0.1 mg1^-1) and could also be micropropagated by subsequent axillary shoot proliferation.     

Growth,graviresponsiveness and abscisic-acid content of Zea mays seedlings treated with Fluridone

Ten-d-old seedlings of Zea mays L. cv. Tx 5855 treated with 1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone (Fluridone) were analyzed for abscisic acid (ABA) content using high-performance liquid chromatography with an analysis sensitivity of 2.5 ng ABA g^-1 fresh weight (FW). Seedlings were divided into three portions: leaves, detipped roots, and root tips (terminal 1.5 mm). Control plants (water treatment only; no Fluridone) were characterized by the following amounts of ABA: leaves, 0.114±0.024 (standard deviation) g ABA g^-1 FW; detipped roots, 0.260±0.039±g ABA g^-1 FW; root tips, no ABA detected. We did not detect any ABA in tissues of Fluridone-treated plants. Primary roots of treated and untreated seedlings were strongly graviresponsive, with no significant differences between the curvatures or the growth rates of primary roots of Fluridone-treated and control seedlings. These results indicate that 1) Fluridone completely inhibits ABA synthesis, and 2) ABA is not necessary for positive gravitropism by primary roots of Zea mays.Abbreviations ABA abscisic acid - Fluridone 1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone - FW fresh weight - SD standard deviation     

Aulacotheca collicola n.sp. (medullosaceae) from the early Pennsylvanian of the Illinois basin

Compressed synangia referable to the medullosan pollen organ genus Aulacotheca Halle have been discovered in Early Pennsylvanian sediments from Rock Island County, Illinois, U.S.A. Specimens were recovered from localized shales containing floral elements suggesting an upland environment. Based on synangial size, morphology, sporangial number, and prepollen type, two distinct forms, A. collicola n.sp. and Aulacotheca sp., are recognized. Synangia of A. collicola are 11–17 × 2.5 – 4.0 mm and have four to six sporangia. Free sporangial tips are acutely pointed and dehiscence is through a longitudinal slit to the inside of the synangium. Prepollen averages 181 × 129 μm and has a monolete suture with median deflection. Sexine on proximal and distal surfaces shows narrow, closely spaced, anastomosing inpockets; distal and lateral walls are separated by a deep, encircling fold. Synangia of Aulacotheca sp. are 21–33 × 3.8 – 5.5 mm and have 4–6 sporangia. Distally, free sporangial tips have a narrow extension, giving a mucronate appearance. Features of these species suggest that greater morphological diversity in synangial and pollen structure occurs in Aulacotheca and the medullosan pteridosperms than previously recognized.     

A survey of dermatophytes isolated from human patients in the United States from 1979 to 1981 with chronological listings of worldwide incidence of five dermatophytes often isolated in the United States

A survey of dermatophytes isolated from patients seeking medical advice was made from 1979 to 1981 in the United States. The survey included 54 locations with data from 40 cities and 2 states. Correlations of these data with that of the other localities of the world were made to illustrate the dynamic epidemiology of several common dermatophytes. The most often isolated dermatophyte in this survey was Trichophyton rubrum having 53.66% of the total for these three calendar years. In a chronological listing of ringworm infections caused by this organism, many areas of the world have reported similar increased incidence of this pathogen. Trichophyton tonsurans was isolated 27.85% of the total. A dramatic increase of this pathogen as a cause of tinea capitis has been observed in most cities of the United States. It has been isolated in 25 different countries of the world. The percentage of isolation of Trichophyton mentagrophytes was 8.56%. This percentage may not be near the true incidence of infection by this dermatophyte because the infections are mild and respond to treatment without the individual seeking medical advice. Since the 1950s the percentage of isolations of the total has dropped for T. mentagrophytes in the United States. Epidermophyton floccosum accounted for 4.36% of the total. In a few areas of the world it causes over 30% of the total of dermatophytoses. Microsporum canis was isolated 3.72% of the total in the United States. It has recently been reported to be the dominant agent of tinea capitis in several South American countries, Tucson, Arizona and Kuwait. Once the dominant pathogen of tinea capitis in children in the United States, it was replaced by Microsporum audouinii before 1960. Today in the United States, M. audouinii only accounts for 0.30% of the total. It is considered eliminated as a pathogen in England. In this survey, isolated less than 1.0% of the total were Microsporum gypseum, Microsporum ferrugineum, Microsporum nanum, Microsporum fulvum and Trichophyton schoenleinii. Trichophyton meginii and Trichophyton terrestre were reported isolated but no numerical data were available.     

The physiology and morphology of two types of electrosensory neurons in the weakly electric fishApteronotus leptorhynchus

Summary Previous anatomical and physiological studies of the gymnotoid electrosensory lateral line lobe (ELLL) suggest that the anatomically identified basilar and non-basilar pyramidal cells correspond to the physiologically defined E and I cells. Intracellular injection of horseradish peroxidase (HRP) into physiologically identified E and I cells confirms this hypothesis. The morphologies and physiological responses of the basilar and non-basilar pyramidal cells were compared. Both types of pyramidal cells have extensive apical dendritic trees that interact with a parallel fiber network in the ELLL. The apical dendritic trees of the non-basilar pyramidal cells have a wider spread along the rostrocaudal axis of the ELLL than those of the basilar pyramidal cells. This difference is discussed in reference to the interaction of these cell types with the parallel fibers of the ELLL. The density of apical dendritic branches was measured and related to the distance of these branches from the cell body. No obvious differences were seen between the dendritic density patterns of basilar and non-basilar pyramidal cells. An interesting correlation, however, exists between the atypical physiological characteristics of two basilar pyramidal cells and their dendritic density patterns. Two cells of the medial (ampullary) segment of the ELLL were analyzed. Like the pyramidal cells of the three lateral (tuberous) regions of the ELLL, the physiology of these cells appears to be related to the presence of an extended basilar process. The ampullary cells, however, have apical dendritic trees that are oriented orthogonally to the dendritic trees of the pyramidal cells.Abbreviations AM amplitude modulation - DML dorsal molecular layer - ELLL electrosensory lateral line lobe - EOD electric organ discharge - HRP horseradish peroxidase - LC lobus caudalis - Npd nucleus praeeminentialis dorsalis - PSTH post stimulus time histogram     

External auditory structures in two species of neotropical notodontid moths

Summary Two species of neotropical moths,Antaea lichyi Franclemont andHapigia curvilinea Schaus (Notodontidae) from Panamá possess paired, cup-like extensions of their pleural segments, reminiscent of mammalian pinnae, that project laterally from the perimeter of the tympanic membrane. These cups are homologous with the post-spiracular abdominal hoods of typical noctuid moths, and may be related to the orientation of the notodontid ear, where the tympanic membrane faces ventrally toward the mid-line of the moth's body and potentially reduces the reception of incident sound energy.Removal of the cups did not alter the neurologically determined best frequencies of either species, nor did it affect the shape ofH. curvilinea's directional sensitivity or its spatial point of maximal sensitivity. Polar threshold curves to stimulus tones of 30 kHz, however, revealed a reduced overall directionality, and thus indicate that the cups may impart a degree of sound localization ability.Both removal and blockage of the external structures result in reduced sensitivities (i.e. increased thresholds) to frequencies higher than approximately 30 kHz. All individuals ofH. curvilinea tested became deaf to tones over 115 kHz when the cups were ablated or blocked.Neotropical moths are exposed to potentially heavy predation pressure from insectivorous bats that characteristically emit faint and/or high frequency echolocation signals, some in excess of 70 kHz (e.g., foliage-gleaning Phyllostomatidae). In certain notodontids, the development of external auditory adaptations that enhance the reception of faint, high frequency sounds may be an evolutionary response to predation pressures by these bats.