Accessory cells induce a polyphosphatidylinositol response when cultured with mitogen-activated T lymphocytes

Monocytes (MO) influenced phosphoinositide metabolism when human T lymphocytes, isolated from peripheral blood, were activated by polyclonal mitogens. In the 3 hr immediately following mitogenic challenge, the synthesis of phosphatidylinositol (PI) was augmented and the synthesis of PI-4-phosphate (PIP) and PI-4,5-bisphosphate (PIP2) was induced in cultures of T lymphocytes and MO. In addition, MO induced a rapid and transient degradation of PIP and PIP2 in T cells prelabeled with [32P]PL and subsequently activated by mitogen. Induction of a PIP/PIP2 response correlated well with induction of DNA replication by MO when T cells were activated by phytohemagglutinin or by neuraminidase plus galactose oxidase. MO did not influence polyphosphoinositide metabolism when T cells were stimulated by the nonmitogenic lectin wheat germ agglutinin. Interleukin 1 could not substitute for monocytes in inducing a polyphosphoinositide response. By causing a rapid and transient release of the second messengers diacylglycerol and inositol phosphates and by subsequently increasing their cellular precursors, MO may induce the interleukin 2 responsive state in T lymphocytes.     

A New Enzymatic Cycling Technique for Glutamate Determination in Brain Microdialysates

A quantitative analysis of glutamate in brain dialysate was made by using an enzymatic cycling technique. This method made it possible to measure the concentration of glutamate in dialysate collected at 30-s intervals. Dialysates were collected from Mongolian gerbil hippocampus before, during, and after two 90-s ischemic insults at an interval of 5 min. An extracellular increase in levels of glutamate was already observed in samples collected during a 30-60 s period after the onset of each ischemia, and the levels of glutamate were maximal at the end of each period of ischemia (approximately a fourfold increase). The increased levels of glutamate rapidly returned almost to preischemic levels by 30 s of recirculation. This method will provide more precise information about temporal changes in the extracellular glutamate concentration in the brain during ischemia.     

Isolation of aldosterone synthase cytochrome P-450 from zona glomerulosa mitochondria of rat adrenal cortex

A cytochrome P-450 capable of producing aldosterone from 11-deoxycorticosterone was purified from the zona glomerulosa of rat adrenal cortex. The enzyme was present in the mitochondria of the zona glomerulosa obtained from sodium-depleted and potassium-repleted rats but scarcely detected in those from untreated rats. It was undetectable in the mitochondria of other zones of the adrenal cortex from both the treated and untreated rats. The cytochrome P-450 was distinguishable from cytochrome P-45011 beta purified from the zonae fasciculata-reticularis mitochondria of the same rats. Molecular weights of the former and the latter cytochromes P-450, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were 49,500 and 51,500, respectively, and their amino acid sequences up to the 20th residue from the N terminus were different from each other at least in one position. The former catalyzed the multihydroxylation reactions of 11-deoxycorticosterone giving corticosterone, 18-hydroxydeoxycorticosterone, 18-hydroxycorticosterone, and a significant amount of aldosterone as products. On the other hand, the latter catalyzed only 11 beta- and 18-hydroxylation reactions of the same substrate to yield either corticosterone or 18-hydroxydeoxycorticosterone. Thus, at least two forms of cytochrome P-450, which catalyze the 11 beta- and 18-hydroxylations of deoxycorticosterone, exist in rat adrenal cortex, but aldosterone synthesis is catalyzed only by the one present in the zona glomerulosa mitochondria.     

Diamine Oxidase from Cultured Roots of Hyoscyamus niger: Its Function in Tropane Alkaloid Biosynthesis

Diamine oxidase was partially purified from cultured roots of Hyoscyamus niger L. that produce considerable amounts of tropane alkaloids, and then characterized. N-Methylated amines inhibited the activity of the enzyme more strongly than the corresponding primary amines. N-Methylputrescine was the best substrate of those studied, the respective K_m values for it and for putrescine and cadaverine being 0.33, 2.85, and 6.25 millimolar. The specificity constants V_max/K_m for putrescine and cadaverine were 11 and 1% of the constant for N-methylputrescine. Marked specificity for the N-methylated diamine would enable the Hyoscyamus enzyme to function specifically in tropane alkaloid biosynthesis.     

A note on the present situation of the primate fauna found from south-eastern Cameroon to northern Congo

Brief results of a survey are reported for the primate fauna in south-eastern Cameroon and northern Congo. The survey was carried over the period from October 1988 to January 1989. I confirmed the occurrence ofMandrillus sphinx in the south-eastern part of Cameroon, viz. the south bank of the Dja river, the occurrence ofCercocebus albigena in almost all the survey areas, the occurrence ofCercopithecus cephus, C. nictitans, C. pogonias, andGorilla g. gorilla throughout the areas, and the occurrence ofCercopithecus neglectus andColobus badius near Bomassa, 70 km north of Ouesso, in Congo. I also confirmedColobus polykomos satanas in some parts of Cameroon, but this species is declining. Local people provided information onCercocebus galeritus agilis, Colobus guereza, andPan troglodytes in almost all the areas, in some of which I confirmed the animals directly. They also provided information aboutCercocebus torquatus on the north bank of the Dja river in Cameroon andMiopithecus talapoin in Sembe in Congo, although I could not confirm these species myself. Human activities had begun reducing the populations of the above primates, particularly those ofMandrillus sphinx, Colobus polykomos satanas, andGorilla g. gorilla, in south-eastern Cameroon and in northern Congo despite the low density of the human populations.     

Demography of agile gibbons (Hylobates agilis)

Demographic processes and the structure of a population of agile gibbons (Hylobates agilis) were investigated over 6 years in the Gunung Palung Reserve, Indonesia. Estimates of population size, density, and biomass revealed a population whose groups were stable in size and composition. Demographic processes place gibbons at risk, however, to short-term changes in their environment. Patterns of survival, fecundity, mortality, and dispersal combined to produce negative rates of growth. In addition, a top-heavy age-class distribution, with adults forming a large fraction of animals, makes it unlikely that this population could recover rapidly from a decline in numbers. Two behavioral factors, territoriality and monogamy, account for the size and stability of gibbon groups. Monogamy imposes limits on group size, while mating patterns and territoriality decrease the impact of sources of high mortality common in other primate species. These relationships underscore the fundamental importance of behavioral influence on demographic processes and social structure.     

The Thermostable Direct Hemolysin Gene (tdh) of Vibrio hollisae Is Dissimilar in Prevalence to and Phylogenetically Distant from the tdh Genes of Other Vibrios: Implications in the Horizontal Transfer of the tdh Gene

Vibrio hollisae strains isolated recently from patients in various locations were examined for the presence of the thermostable direct hemolysin gene (tdh) using nucleic acid hybridization and polymerase chain reaction assays. The results were consistent with the previous finding that all strains of V. hollisae carry the tdh gene. In contrast, the tdh gene has been detected in a minority of strains for other Vibrio species (V. parahaemolyticus, V. cholerae non-O1, and V. mimicus). Detailed phylogenetic analysis showed that the tdh genes of the non-V. hollisae species were very closely related to each other and that the tdh gene of V. hollisae was distantly related to the tdh genes of the non-V. hollisae species. These results and the proposed insertion sequence-mediated tdh transfer mechanism suggest that the tdh gene may have been maintained stably in V. hollisae and that the tdh genes of the non-V. hollisae species may have been involved in recent horizontal transfer.     

High-resolution solution structure of siamycin II: Novel amphipathic character of a 21-residue peptide that inhibits HIV fusion

Summary The 21-amino acid peptides siamycin II (BMY-29303) and siamycin I (BMY-29304), derived from Streptomyces strains AA3891 and AA6532, respectively, have been found to inhibit HIV-1 fusion and viral replication in cell culture. The primary sequence of siamycin II is CLGIGSCNDFAGCGYAIVCFW. Siamycin I differs by only one amino acid; it has a valine residue at position 4. In both peptides, disulfide bonds link Cys¹ with Cys¹³ and Cys⁷ with Cys¹⁹, and the side chain of Asp⁹ forms an amide bond with the N-terminus. Siamycin II, when dissolved in a 50:50 mixture of DMSO and H₂O, yields NOESY spectra with exceptional numbers of cross peaks for a peptide of this size. We have used 335 NOE distance constraints and 13 dihedral angle constraints to generate an ensemble of 30 siamycin II structures; these have average backbone atom and all heavy atom rmsd values to the mean coordinates of 0.24 and 0.52 Å, respectively. The peptide displays an unusual wedge-shaped structure, with one face being predominantly hydrophobic and the other being predominantly hydrophilic. Chemical shift and NOE data show that the siamycin I structure is essentially identical to siamycin II. These peptides may act by preventing oligomerization of the HIV transmembrane glycoprotein gp41, or by interfering with interactions between gp41 and the envelope glycoprotein gp120, the cell membrane or membrane-bound proteins [Frèchet, D. et al. (1994) Biochemistry, 33, 42–50]. The amphipathic nature of siamycin II and siamycin I suggests that a polar (or apolar) site on the target protein may be masked by the apolar (or polar) face of the peptide upon peptide/protein complexation.Abbreviations ABNR adopted basis Newton Raphson - AIDS acquired immunodeficiency syndrome - CW continuous wave - DMSO dimethylsulfoxide - DQF-COSY two-dimensional double-quantum-filtered correlation spectroscopy - HIV human immunodeficiency virus - HSQC heteronuclear single-quantum coherence - NOE nuclear Overhauser enhancement - NOESY two-dimensional nuclear Overhauser enhancement spectroscopy - ppm parts per million - P.E.-COSY two-dimensional primitive exclusive correlation spectroscopy - REDAC redundant dihedral angle constraint - rf radio frequency - rmsd root-mean-square difference - SIV simian immunodeficiency virus - sw spectral width - _m mixing time - TOCSY two-dimensional total correlation spectroscopy - TSP trimethylsilyl-2,2,3,3-²H₄-propionate - 2D two-dimensional