Bone Marrow Depletion as a Coincidental Finding to Hypothermia in Macaca mulatta

Three of 16 juvenile rhesus monkeys (Macaca mulatta) and 1 rhesus of 79 adult rhesus and cynomolgus monkeys (Macaca fascicularis) were found comatose in a state of profound hypothermia after a heating failure occurred in the room in which they were housed. One juvenile monkey died shortly thereafter. The three other monkeys were revived with gradual warming and supportive therapy but later experienced separate acute clinical crises manifesting shock and died at 19, 31, and 51 days after the initial episode. Histopathologic findings of severe bone marrow depletion were observed in each of the three monkeys that died after the initial episode.     

High Numbers of Prosthecate Bacteria in Pulp Mill Waste Aeration Lagoons

Prosthecate bacteria comprised 0.6 to 10.5% of the bacterial community in samples from 11 pulp mill waste aeration lagoons. Because of their distinct morphology, the genera Ancalomicrobium, Caulobacter, Prosthecobacter, Prosthecomicrobium, Stella, and Hyphomicrobium or Hyphomonas could be identified and enumerated by direct microscopic examination. Monthly samples from one lagoon showed that several genera varied from undetectable to predominant among the appendaged organisms. Temperature (season), type of wood pulped, and pulping process did not significantly affect the density of prosthecate bacteria.     

Functional group contributions to the partitioning of phenols between liposomes and water

The temperature dependency of the partitioning of p-alkylphenols and p-halophenols has been determined between dimyristoyl phosphatidylcholine liposomes and 0.15 M NaCl. Partition coefficients increased as a function of temperature below the endothermic phase transition temperature (T_c) of the phospholipid but decreased above this temperature. The transfer process was found to be entropy-dominated below and enthalpy-dominated above the T_c, although large negative entropy changes were observed. Regular changes in the thermodynamic functions, partition coefficients and functional group free energies occurred as a function of the alkyl chain length or size of the halogen substituent below but not above the T_c. This has tentatively been attributed to increased phenol-phospholipid interaction at the higher temperatures. The partitioning of p-fluorophenol behaved in a manner expected of fluorinated compounds, yielding relatively low partition coefficients, but it produced an additional effect of markedly lowering the T_c of dimyristoyl phosphatidylcholine. Good correlations of the partition coefficients in liposomes with those in bulk organic solvents and with molecular size of the solute have been obtained.     

Evidence for a highly differentiated sex chromosome heteromorphism in the salamander Necturus maculosus (Rafinesque)

The mitotic chromosomes of the neotenic (sensu Gould, 1977, and Alberch et al., 1979) salamander Necturus maculosus (Rafinesque) have been examined using a C-band technique to demonstrate the distribution of heterochromatin. The C-banded mitotic chromosomes provide evidence of a highly differentiated XY male/XX female sex chromosome heteromorphism, in which the X and Y chromosomes differ greatly in size and morphology, and in the amount and distribution of C-band heterochromatin. The X chromosome represents one of the largest biarmed chromosomes in the karyotype and is indistinguishable from similar sized autosomes on the basis of C-band heterochromatin. The Y chromosome, on the other hand, is diminutive, morphologically distinct from all other chromosomes of the karyotype, and is composed almost entirely of C-band heterochromatin. The discovery of an X/Y chromosome heteromorphism in this species is consistent with the observation by King (1912) of a heteromorphic spermatogenic bivalent. Karyological and phylogenetic implications are discussed.     

Unusual Modification of Bacteriophage Mu DNA

Bacteriophage Mu DNA was labeled after induction in the presence of [2-(3)H]adenine or [8-(3)H]adenine. Both Mu mom(+).dam(+) DNA and Mu mom(-).dam(+) DNA have similar N(6)-methyladenine (MeAde) contents, as well as similar frequencies of MeAde nearest neighbors. Both DNAs are sensitive to in vitro cleavage by R.DpnI but resistant to cleavage by R.DpnII. These results indicate that the mom(+) protein does not alter the sequence specificity of the host dam(+) methylase to produce MeAde at new sites. However, we have discovered a new modified base, denoted A(x), in Mu mom(+).dam(+) DNA; approximately 15% of the adenine residues are modified to A(x). Although the precise nature of the modification is not yet defined, analysis by electrophoresis and chromatography indicates that the N(6)-amino group is not the site of modification, and that the added moiety contains a free carboxyl group. A(x) is not present in Mu mom(+).dam(+) or Mu mom(-).dam(+) phage DNA or in cellular DNA from uninduced Mu mom(+).dam(+) lysogens. These results suggest that expression of the dam(+) and mom(+) genes are required for the A(x) modification and that this modification is responsible for protecting Mu DNA against certain restriction nucleases. Mu mom(+).dam(-) DNA and Mu mom(-).dam(-) DNA contain a very low level of MeAde (ca. 1 MeAde per 5,000 adenine residues). Since the only nearest neighbor to MeAde appears to be cytosine, we suggest that the methylated sequence is 5'... C-A(*)-C... 3' and that this methylation is mediated by the EcoK modification enzyme.     

Granulocyte macrophage-colony stimulating factor stimulates the synthesis of membrane and nuclear proteins in murine neutrophils

The effect of granulocyte macrophage-colony stimulating factor (GM-CSF), a well-characterized hemopoietic regulator, on protein synthesis in murine bone marrow neutrophils is described. Bone marrow neutrophils in excess of 95% purity were obtained by fluorescence-activated cell sorting. While GM-CSF did not appear to slow the rate of dying of peritoneal exudate neutorphils or thymus cells, the viability of bone marrow neutrophils after 17 hr was enhanced (40%) by GM-CSF. GM-CFS had no effect on total 35S-methionine incorporation by thymocytes or peritoneal exudate neutrophils over a 17-hr incubation period; however, bone marrow neutrophils showed increased incorporation (approximately 10%) at all times between 5-17 hr. As viability and 35S-methionine incorporation of bone marrow neutrophils at 5 hr were minimally affected by GM-CSF, this time point was chosen to study the effect of GM-CSF on the synthesis of particular proteins. Two-dimensional polyacrylamide gels of 35S-methionine-labelled lysates were prepared from whole cells, isolated nuclei, and membranes. Quantitative analysis of the fluorograms obtained from the two-dimensional electropherograms by a computer-linked optical data digitiser indicated that out of a total of 180 proteins, the amount of label contained in 11 proteins was significantly higher in the presence of GM-CSF, while three proteins, apparently of cytoplasmic origin, contained less label than control cells. Eight of these proteins were identified as nuclear, and one was membrane derived. Attempts have been made to identify some of the inducible proteins and to correlate results with other studies of normal hemopoietic and leukemic cells. The significance and multiple functions of GM-CSF in hemopoiesis are discussed.     

Multiphasic activation of smooth muscle adenylate cyclase by pretreatment with guanyl-5′-yl imidodiphosphate (Gpp(NH)p) suggests multiple enzyme populations

The activation of uterine smooth muscle adenylate cyclase was studied by pretreating the particulate form of the enzyme with the GTP analog guanyl-5′-yl imidodiphosphate (Gpp(NH)p). Pretreatment with Gpp(NH)p left the enzyme in an irreversibly activated state which survived subsequent washing in guanyl nucleotide-free buffer. Activation under these conditions was multiphasic with rapid and slow components. At 23 °C slow activation proceeded at about $\text{1}\text{10}\text{th}$ the rate of rapid activation. The onset of the slow phase took longer at lower temperatures. Routine adenylate cyclase assay conditions (conversion of [³²P]ATP to cyclic [³²P]AMP) carried out without pretreatment probably characterized the rapidly activated component. The simplest kinetic model suggests not only the generally accepted two-step association reaction, but also implies the existence of more than one enzyme form, each of which is characterized by a separate activation rate. The complex kinetics of activation might be explained by a heterogeneous mixture of unassociated and preassociated nucleotide binding and catalytic subunits.     

The effect of AZT on in vitro lymphokine-activated killer (LAK) activity in human immunodeficiency virus type-1 (HIV-1) infected individuals

Human immunodeficiency virus type-1 (HIV-1)-infected individuals exhibit functional impairment in various forms of cell-mediated cytotoxicities (CMC) at all stages of disease. The purpose of this study was to determine (i) if peripheral blood mononuclear cells (PBMC) obtained from HIV-1-infected patients could be stimulated in vitro to yield lymphokine-activated killer (LAK) activity; (ii) if non-MHC-restricted gp120-specific CMC could be preserved; and (iii) what effect zidovudine (AZT) would have on LAK activity. Fourteen asymptomatic HIV-1 seropositive adults and five healthy seronegative adults (controls) were evaluated. PBMCs were isolated and incubated in media or supplemented with IL-2 for 4 or 72 hr. Lysis of the NK resistant target cell line, Daudi, was similar for the control and experimental group. The increase in activity after stimulation was elevated to a similar degree in both seronegative and seropositive groups (P less than 0.001). LAK activity was significantly decreased (P = 0.011) when AZT was added to LAK cultures. In addition, virus production may not have been completely inhibited by AZT in LAK cultures. Thus, PBMCs from asymptomatic HIV-1-infected patients could be stimulated to yield LAK activity. However, AZT can impair LAK generation. It is unclear if LAK activation results in virus production that cannot be inhibited by AZT in this system. Further definition in other patient populations is required prior to applying this information to clinical trials.