A rare missense mutation in CHRNA4 associates with smoking behavior and its consequences

Using Icelandic whole-genome sequence data and an imputation approach we searched for rare sequence variants in CHRNA4 and tested them for association with nicotine dependence. We show that carriers of a rare missense variant (allele frequency=0.24%) within CHRNA4, encoding an R336C substitution, have greater risk of nicotine addiction than non-carriers as assessed by the Fagerstrom Test for Nicotine Dependence (P=1.2 × 10(-4)). The variant also confers risk of several serious smoking-related diseases previously shown to be associated with the D398N substitution in CHRNA5. We observed odds ratios (ORs) of 1.7-2.3 for lung cancer (LC; P=4.0 × 10(-4)), chronic obstructive pulmonary disease (COPD; P=9.3 × 10(-4)), peripheral artery disease (PAD; P=0.090) and abdominal aortic aneurysms (AAAs; P=0.12), and the variant associates strongly with the early-onset forms of LC (OR=4.49, P=2.2 × 10(-4)), COPD (OR=3.22, P=2.9 × 10(-4)), PAD (OR=3.47, P=9.2 × 10(-3)) and AAA (OR=6.44, P=6.3 × 10(-3)). Joint analysis of the four smoking-related diseases reveals significant association (P=6.8 × 10(-5)), particularly for early-onset cases (P=2.1 × 10(-7)). Our results are in agreement with functional studies showing that the human α4β2 isoform of the channel containing R336C has less sensitivity for its agonists than the wild-type form following nicotine incubation.

Is alpha-Synuclein Pathology a Target for Treatment of Neurodegenerative Disorders?

Alpha-synuclein is the main constituent of intra-neuronal Lewy bodies, which are characteristic of Parkinson's disease, but aggregates are also found as axonal inclusions. Alpha-synuclein pathology is found together with beta-amyloid plaques and neurofibrillary tangles in Alzheimer's disease and other neurodegenerative disorders. In spite of the fact that the biological function of this synaptic protein is not known so far, there is an increasing body of evidence indicating an interaction with amyloid peptides, but also with tau-hyperphosphorylation. A high proportion of alpha-synuclein purified from Lewy bodies is phosphorylated on Ser129. There are still different opinions about the toxicity of the alpha-synuclein aggregates. Alpha-synuclein seems to influence different intracellular signaling pathways which are in direct relation to defense mechanisms against reactive oxygen species or apoptosis. It is obvious that overproduction of alpha-synuclein, but also different mutations, are inducing the formation of aggregates. Because of the possible link to neurodegeneration, different attempts have been made to counteract alpha-synuclein aggregation. An interesting approach is utilizing beta-synuclein, a biological factor, with an aminoacid sequence closely resembling that of alpha-synuclein. Proof of concept studies indicated that overexpression of beta-synuclein is able to counteract alpha-synuclein aggregation in a transgenic animal model, while also ameliorating functional deficits. As an alternative approach, the use of low molecular beta-synuclein N-terminal peptide derivatives has been considered. Several of these structures displayed clear neuroprotective activities in tissue culture models of neurodegeneration, including beta-amyloid toxicity. Therefore it has been speculated that these compounds might have a broad therapeutic efficacy in different neurodegenerative disorders. A proof of concept study in hAPP-transgenic animals resulted in a highly significant decrease in beta-amyloid plaque load, an increase in soluble beta-amyloid peptides and a decrease in insoluble forms. There was also significant improvement of cognitive deficits in this APP transgenic mouse model following intranasal but also peripheral treatment with three of these compounds. From this study it is concluded that the observed effects of the peptides derived from beta-synuclein N-terminus are depending on both, a direct interaction with aggregation of proteins, but also with stimulation of anti-apoptotic and anti-oxidative intracellular signaling pathways.

FISHing for lung cancer: Promising findings using multi-targeted interphase fluorescence in situ hybridization (FISH) for lung cancer detection in sputum

7567

Background: Lung CT imaging shows promise for early lung cancer detection, but may be insensitive for central lesions and will create a need for complementary biomarkers to guide clinical decisions. Methods: We have been conducting a prospective study to assess the performance of various biomarkers in sputum to detect lung cancer. Within a cohort of 3,269 people at high risk for lung cancer (over 30 pack-years of cigarette use and chronic obstructive lung disease) we have conducted a nested case-control study to assay stored samples from 85 incident lung cancer cases and 73 controls for cytologic morphology, DNA methylation, and multi-targeted FISH assays (LAVysion, Vysis/Abbott Molecular). The FISH assay targeted DNA sequences from centromere 6, 5p15.2, 7p12 (EGFR), and 8q24 (cMYC). Cytology was classified as abnormal if moderate or greater atypia was observed, methylation was abnormal if three or more of 8 selected genes were methylated, and FISH was abnormal if two or more scored cells were observed to contain chromosomal aneuploidy indicated by signal gain for at least two targets or signal gain for one and signal loss for two or more targets. Results: Among all subjects, regardless of the time between sputum collection and diagnosis, FISH was abnormal in 49/87 cases (56%) and 5/73 controls (7%) (odds ratio (OR) = 17.5, 95% CI = 6.4 to 47.8). Considering only the cases for which sputum had been collected within 18 months before the lung cancer diagnosis, FISH was abnormal in 37/49 cases (75%) and in 3/38 controls (8%) (OR = 36.0, 95% CI = 9.4 to 138). For this same time period, cytological atypia was abnormal in 37% of cases and 22% of controls (OR = 2.1, 95% CI = 0.8 to 5.3) and methylation was abnormal in 64% of cases and 36% of controls (OR = 4.5, 95% CI = 1.0 to 19.8). Conclusions: The LAVysion FISH assay is more sensitive than other currently available sputum tests for the prediction of invasive carcinoma in subjects and is highly specific with a low frequency of false positive and false negative results. The results suggest that chromosomal aneuploidy and by extrapolation, missegregation, are features of advanced premalignancy and should identify patients who are proximate to clinically overt lung cancer.

[Table: see text]

Chromosomal aneusomy in sputum predicts for lung cancer in nested case-control study

7201

Background: Lung cancer usually is disseminated at diagnosis and prognosis is poor for most patients. Heavy smokers are known to be at high risk factor for lung cancer and are target population for lung cancer prevention. Sputum has long been considered a potential source of material for biomarker based early detection but no tests have been validated. Methods: Chromosome aneusomy was sought in sputum of 114 cases and 110 controls from the Colorado Sputum Screening Cohort Study, which includes heavy smokers with airflow obstruction matched on age, gender, and date of sample collection. Subject characteristics were as follows: mean age 67 (± 8 years), 75% males, 36% current smokers, mean pack-year 71.2 (± 33.5). The FISH probe LAVysion (Vysis/Abbott) was used, including the DNA targets EGFR, MYCC, 5p15 and CEP6. Results: The multi-target set showed the highest sensitivity (0.78) and specificity (0.95) rates in specimens collected within 12 months of lung cancer diagnosis. The individual probes EGFR, MYCC, 5p15 and CEP6 showed, respectively, decreasing sensitivity rates (0.78, 0.67, 0.62, and 0.29) and increasing specificity rates (0.84, 0.91. 0.86, and 0.95). Combinations of two specific probes (AND) or of any of two probes (OR) have not favorably impacted these coefficients. Proportion of abnormal sputum specimens was higher in squamous cell carcinoma than in adenocarcinoma or small cell carcinoma, both considering the set of specimens collected 12 months prior to disease diagnosis (92%, 75%, 60%) and all specimens (80%, 58%, 44%). Conclusions: Chromosomal aneusomy in sputum was demonstrated in a nested case-control cohort to be a promising marker for prediction of lung cancer risk in heavy smokers with airflow obstruction. Evaluation of four DNA targets was more effective than any single marker or combination of markers, and the test had high sensitivity in patients with squamous cell carcinoma.

[Table: see text]

Polar expression and phosphorylation of human leptin receptor isoforms in paired, syncytial, microvillous and basal membranes from human term placenta

The hormone leptin (OB) and its receptor (OB-R) are key homeostatic regulators of mammalian body weight. Two predominant isoforms of OB-R are expressed by alternative splicing: the long form, OB-RL, with full signalling capacity is highly expressed in the hypothalamus and the short, signalling-defective form, OB-Rs, is ubiquitously expressed. In a previous study we detected expression of OB-RL and OB-Rs in human syncytiotrophoblast cells using in situ hybridization and immunohistochemistry (Bodner et al., 1999). The aim of this study was to investigate leptin receptor isoform expression and phosphorylation in paired, syncytial, microvillous and basal membranes from human term placenta by Western blot analysis. Both the OB-RL and the OB-Rs isoforms were detected in the syncytial membrane preparations. The OB-RL isoform was observed exclusively in microvillous membranes, whereas the OB-Rs isoform was found in both microvillous and basal membrane preparations. No significant differences were observed between syncytial membranes from normal and type 1 diabetic pregnancies. To test the phosphorylation capacity of the OB-R isoforms, microvillous and basal membrane vesicles loaded with ATP were stimulated with leptin and the phosphorylation status of the OB-R at the tyrosine 985 (Y985) was determined. A single band at the molecular weight corresponding to the molecular weight of the OB-RL isoform was detected exclusively in the ATP-loaded microvillous vesicles. We conclude that the long form OB-RL is expressed exclusively in the microvillous membrane of the syncytiotrophoblast and is capable of being phosphorylated, suggesting that it has signal transduction capacity.

Lipoprotein profile and cholesteryl ester transfer protein in neonates

Undernourishment in utero appears to be associated with persisting changes in the metabolic, endocrine, and immune functions. In this study, we determined the influence of birth weight on the lipoprotein profile and cholesteryl ester transfer protein (CETP), which promotes a proatherogenic lipoprotein profile in plasma by determining the chemical, physical, and biologic properties of the respective lipoprotein particles. Triglyceride (TG) concentrations were highest and high-density lipoprotein (HDL)(2)-cholesterol levels were lowest in small for gestational age (SGA) neonates. CETP-mass was determined by enzyme-linked immunosorbent assay (ELISA) and CETP-activity by using exogenous lipoproteins. Cholesteryl ester transfer was determined as transfer of radiolabeled cholesteryl esters (CE) from HDL to apolipoprotein B-containing lipoproteins. CETP mass was lowest and cholesteryl ester transfer was highest in SGA neonates. CETP-activity did not differ among the neonates. Our results suggest that increased and decreased nourishment in utero affects the lipoprotein profile and CETP in neonates. High TG and low HDL(2) levels in SGA neonates might result from increased cholesteryl ester transfer and, may in part, explain the increased risk of coronary heart disease (CHD) of small for gestational age neonates in later life.

Fetal leptin and insulin levels only correlate inlarge-for-gestational age infants

OBJECTIVE

To determine whether fetal leptin levels correlate with fetal weight and whether such correlation is direct or indirect via insulin or human placental lactogen (hPL), respectively.

DESIGN

Cross-sectional study of offspring at term (n=175) with over-representation of large-for-gestational age (LGA; n=70) and small-for-gestational age (SGA; n=23) cases in a population of Caucasian women with no pregnancy pathology.

METHODS

Fetal cord blood was collected after delivery. In several cases (n=62) paired mother-fetus blood samples were obtained. Leptin, insulin and hPL levels were measured by RIA. Anthropometric data (birth weight, body mass index, placental weight) were recorded.

RESULTS AND CONCLUSIONS

Maternal insulin, hPL and leptin levels were higher than fetal concentrations. Cord blood leptin levels positively correlated with the anthropometric data with stronger correlations in female (0.54<r<0.66) than in male (0.32<r<0.39) neonates. Cord blood leptin levels did not differ between appropriate-for-gestational age (AGA; n=82) and SGA (n=23) neonates, but were higher (P<0.001) by 83% in LGA (n=70) than in AGA neonates. Among the different weight classes the correlations between fetal leptin and anthropometric data were only observed in LGAs, but not in AGAs or SGAs. Fetal, but not maternal, leptin levels strongly correlated with fetal insulin (r=0.56; P<0.001). After accounting for this close relationship insulin could no longer be used to predict birth weight (r=0.15, P=0.051). We suggest that the correlation of cord blood insulin with neonatal weight in LGAs is, in addition to insulin's direct anabolic action, indirectly mediated via leptin. It is hypothesized that fetal insulin stimulates fetal adipocyte leptin production.

Leptin receptor in human term placenta: in situ hybridization and immunohistochemical localization

In the present study, we investigated the expression and localization of leptin receptors in human term placentae. On human term placenta tissue slices, digoxigenin-UTP labelled RNA-probe detected the long form of the leptin receptor ObR(L)mRNA in syncytiotrophoblasts of the villi, whereas the haematological subtype of the leptin receptor ObR/B219.1 was detected in blood cells of the intervillous space and fetal vessels. Immunohistochemistry, with two polyclonal antibodies to the N-terminus recognizing ObR(L)and ObR(S)of the leptin receptors and one to the C-terminus recognizing the long form of the leptin receptor ObR(L), localized leptin receptor protein at the apical membrane of the syncytiotrophoblasts. Our results show that the long form of the leptin receptor ObR(L)is expressed in human term placentae. We localized the long form of leptin receptor mRNA to the cytoplasm of syncytiotrophoblasts and leptin receptor proteins in human term placentae to the apical membrane of syncytiotrophoblasts. We conclude that in term placentae, leptin could mediate a growth promoting effect in the fetoplacental unit through the long form of the leptin receptor localized in the syncytiotrophoblasts. In contrast, the haematological subtype of the leptin receptor is not expressed in placental cells, but solely by blood cells in the intervillous space and fetal vessels.

[Leptin--an interim evaluation]

The discovery of leptin, the product of the obese (ob)-gene, has broadened the horizons of research on energy balance. This hormone, produced and secreted by adipose tissue and some placental cells, finds its way to the hypothalamus, where it binds to the leptin receptors and signals satiety through the neuroendocrine axis. The fact that adipose tissue is not merely a storage depot, but also an important endocrine tissue, has revived the interest in the "lipostatic" theory of body fat regulation and has initiated many research efforts in the field of obesity, anorexia nervosa, bulimia, reproduction and haematology.

Lipoprotein lipase, LDL receptors and apo-lipoproteins in human fetal membranes at term

Ultrastructurally, all cells of human fetal membranes strongly exhibit a large amount of lipid deposits throughout pregnancy. Their origin and function is still unknown. The aim of this study was to investigate the localization of key components of lipid metabolism in this tissue. Using immunohistochemical techniques, the distribution of lipoprotein lipase (LPL), low density lipoprotein receptors (LDL receptors), and apo-lipoprotein B and E was investigated in 20 human fetal membranes at term. In addition, electron microscopy was used to study the intracellular localization of lipoprotein-sized particles. Amnionic epithelium and trophoblast cells reacted strongly for LPL. LDL receptors and apo-lipoproteins were present in amnionic epithelium and fibroblasts of the amnion. In none of the investigated cells were lipoprotein-sized particles identified. Similar results were obtained in all 20 cases. The findings indicate that lipoprotein from the amniotic fluid or from the maternal circulation may serve as substrate for lipids in human fetal membranes.

Dopamine and intestinal mucosal tissue oxygenation in a porcine model of haemorrhage

Haemorrhage is associated with intestinal mucosal hypoxia and impaired gut barrier function. Dopamine increases oxygen delivery to the intestinal mucosa and may thus counteract haemorrhage-induced mucosal hypoxia. Jejunal mucosal tissue oxygen tension (mucosal PO2) and jejunal oxygen saturation of mucosal microvascular haemoglobin (mucosal HbO2) were measured in 14 anaesthetized pigs. Seven animals served as controls (group C) and seven received continuous infusion of dopamine 16 micrograms kg-1 min-1 (group D) while 45% of blood volume was removed in three equal increments. Resuscitation was performed using shed blood and fluid. Mean arterial pressure and systemic oxygen delivery decreasing significantly during haemorrhage and returned to baseline after resuscitation in both groups. Mucosal PO2 decreased from 4.4 to 1.7 kPa after haemorrhage (P < 0.01) and further to 1.5 kPa after resuscitation (P < 0.01) in group C whereas group D showed an increase from 3.9 to 5.9 kPa after the start of the dopamine infusion (P < 0.05), but no significant difference from baseline after haemorrhage (2.3 kPa) (ns) or resuscitation (3.1 kPa) (ns). Mucosal HbO2 decreased from 52 to 32% after haemorrhage (P < 0.05) and increased to near baseline (37%) (ns) after resuscitation in group C whereas group D showed no significant changes from baseline (54%) throughout the experiment. Comparison between groups showed higher mucosal PO2 and HbO2 values for group D animals after the start of the dopamine infusion (P < 0.05 each), after the first two steps of haemorrhage (P < 0.01 each) and after resuscitation (P < 0.05 each). We conclude that i.v. dopamine 16 micrograms kg-1 min-1 improved tissue oxygenation of the small intestinal mucosa during moderate haemorrhage and subsequent resuscitation.

Location of insulin receptors in the placenta and its progenitor tissues

The insulin receptor gene is constitutively expressed, so the presence of insulin receptor proteins might be expected on all mammalian tissues, with the plasma membrane as the predominant site of receptor location. Results reviewed here indicate that insulin receptors are also present in all placental tissues and the placenta's progenitor tissues and cells, i.e., oocytes, spermatozoa, and preimplantation embryos, in most of the species studied. Receptor densities, however, vary among individual cells and cell types and at various developmental stages. Three aspects deserve emphasis. 1) In human placenta, the insulin receptor distribution pattern is characterized by a spatiotemporal change between first trimester and term. At the beginning of pregnancy, insulin receptors are found predominantly on the maternal side (apical membrane of syncytiotrophoblast, low density on cytotrophoblast); at term, however, they are on the fetal side (lining the fetal vessels). This suggests that, in the first trimester, maternal insulin regulates insulin-dependent processes, whereas, at term, it must be fetal insulin mainly controlling these processes. 2) The majority of insulin receptors is expressed on structures that are currently assumed to drive placental growth, i.e., syncytial sprouts and mesenchymal villi in first-trimester placentas and fetal endothelium at term. Therefore, we hypothesize a growth-promoting function, among others, of insulin on the placenta. 3) At present, no histologic evidence is available to demonstrate insulin receptors in structures commonly associated with receptor-mediated endocytosis. Whether placental insulin receptors are internalized, therefore, awaits clarification.

Idiotype vaccination strategies against a murine B-cell lymphoma: dendritic cells loaded with idiotype and bispecific idiotype x anti-class II antibodies can protect against tumor growth

Three strategies were used to evaluate 38C13 B-cell lymphoma-specific idiotype immunization to protect against subsequent lymphoma challenge in C3H/He mice. It was observed that tumor-specific immunity could be induced by immunization with (i) KLH-conjugated 38C13 B-cell lymphoma idiotype in complete Freund's adjuvants (survival rate 80%), (ii) dendritic cells pulsed in vitro with native idiotype protein (survival rate 80%), and (iii) bispecific antibodies composed of B-lymphoma-related idiotype and an MHC class II binding moiety (survival rate 40%). Presentation of idiotype determinants by dendritic cells or bispecific antibody resulted in lymphoma-specific immunity and obviated the requirement for carrier protein or adjuvant. Moreover, primed dendritic cells induced predominant development of a tumor-specific T-cell response. Each of these immunization strategies resulted in long-term survival without the emergence of idiotype variants or the induction of tumor dormancy.

Effects of short-term endotoxemia and dopamine on mucosal oxygenation in porcine jejunum

Effects of Escherichia coli lipopolysaccharide (2 micrograms.kg-1.20 min-1; LPS), given systemically (S) or via superior mesenteric artery (M), and consecutive dopamine infusion (16 micrograms.kg-1.20 min-1) on jejunal mucosal tissue O2 tension (PO2muc) and serosal tissue O2 tension (PO2ser; Clark-type surface electrodes) and jejunal mucosal microvascular hemoglobin O2 saturation (HbO2muc; tissue reflectance spectrophotometry) were investigated in a hemodynamically stable pig model. Twenty-one pigs were anesthetized, paralyzed, and mechanically ventilated. After laparotomy, a mesenteric venous catheter was inserted and a jejunal antimesenteric enterotomy performed. LPS-infused animals developed similar degrees of pulmonary hypertension. No differences in cardiac output and mean arterial blood pressure between groups were found. PO2muc and HbO2muc were significantly lower in M animals compared with control (C) [210 min; PO2muc: 7.12 +/- 1.81 (M), 19.01 +/- 3.12 mmHg (C); HbO2muc: 28.78 +/- 3.36 (M), 49.09 +/- 3.84% (C)], whereas S animals ranged in between (PO2muc: 13.36 +/- 2.2 mmHg; HbO2muc: 40.68 +/- 4.43%). Of measured PO2muc values, 12.6 (C), 20.6 (S), and 46.3% (M) ranged from 0 to 5 mmHg. PO2ser was lower in LPS animals compared with control [59.43 +/- 5.4 (C), 45.00 +/- 6.12 (S), 47.33 +/- 4.34 (M) mmHg]. Dopamine increased PO2muc and HbO2muc to similar absolute values and significantly decreased frequency of PO2muc (0-5 mmHg) in M animals. We conclude that LPS impairs mucosal tissue oxygenation independently of systemic hemodynamics. Mucosal microvascular dysfunction depends on regional LPS concentrations. Under conditions of compromised tissue oxygenation, dopamine significantly improves PO2muc and HbO2muc.

Immunohistochemical localization of glucose transporters and insulin receptors in human fetal membranes at term

The localization has been investigated of the isoforms GLUT1, GLUT3 and GLUT4 of glucose transporter proteins as well as of insulin receptors. Fetal membranes (n = 10) were examined by immunohistochemical methods at the light and electron microscopic levels using mono- and polyclonal antibodies. In all amnion epithelial cells, GLUT1 and GLUT3 antibodies were bound to the apical membrane. Very rarely the GLUT1 antibody also immunostained the basolateral membrane and reacted weakly with the endomembrane system and membranes of the lateral cell protrusions. Fibroblasts reacted with the antibodies against GLUT1, GLUT4 and insulin receptor, whereas they were labelled only in one case with GLUT3 antibody. Cytotrophoblast cells were only stained with antibodies against GLUT1 and GLUT3. Antibodies against GLUT4 only reacted with fibroblasts in the membranes. On amnion epithelial cells, weak immunoreactivity with insulin receptor antibodies was detected only at the electron microscopic level. The data indicate: (1) GLUT1 is located on all cells of the amnion, whereas GLUT3 is present in detectable amounts only on amnion epithelial cells and cytotrophoblast; (2) GLUT1 and GLUT3 on amnion epithelial cells are predominantly located on the apical surface; (3) GLUT4 and insulin receptors are not regularly expressed. We suggest that amnion epithelial cells cover their basal glucose requirements from the amniotic fluid and not from the maternal circulation.

Immunocytochemical analysis of the cytoskeleton of the human amniotic epithelium

The amniotic epithelium constitutes a diffusion barrier controlling the passage of solutes and water between the amniotic cavity and maternal circulation. With the present immunocytochemical approach, we have shown that several major components of the cyto-skeleton, i.e., actin, alpha-actinin, spectrin and ezrin, are preferentially associated with the apical and lateral cell surfaces of the human amniotic epithelium. Keratins are distributed throughout the entire cytoplasm, whereas vimentin mainly forms a perinuclear scaffold. These findings indicate a role of the various components of the cytoskeleton in the structural integrity and modulation of cell shape and junctional permeability.

Early intervention in low back disability among coal miners in West Virginia: negative findings

A major issue in the field of workers' compensation is cost containment, not only of medical costs, but of extended disability costs as well. For a 9-month period in 1985 to 1986, the West Virginia Workers' Compensation Fund tested an early intervention case management approach begun within 2 weeks after injury and found it not to be cost effective. In a controlled study of 284 reported back injuries among underground coal miners, medical costs increased with the case management intervention, although only to the extent of the added costs of the intervention, and disability costs and time lost from work did not decrease. Permanent partial disability awards, litigation rates, number of hospitalizations, and return to work were similar between both the experimental and control groups. Regression analyses of 25 factors identified factors most highly predictive of disability and medical costs, but in predicting extended disability, although the factors were 100% sensitive, they were only 43.6% specific. The case management approach was insufficient to prevent extended disability or to lower medical costs.

Ultrastructure of methanotrophic yeasts

The cellular structure of two yeast strains capable of growth on methane was investigated by electron microscopy. Microbodies were observed in cells of Sporobolomyces roseus strain Y and Rhodotorula glutinis strain CY when grown on methane but rarely when grown on glucose. The size of the microbodies and the number observed per cell in a thin section did not increase with culture age. No crystalline organization was observed within these organelles. Similar microbodies were also observed in cells of R. glutinis CY grown on hexadecane. The plasma membranes of both methane and hexadecane-grown cells exhibited increased invagination compared to that of glucose-grown cells. Catalase activity was detected in the microbodies of alkane-grown cells by using 3,3'-diaminobenzidine as a cytochemical stain. The data presented suggest that microbodies, and the catalase contained within them, play a role in eucaryotic methane metabolism.

Method for rapid separation of immunoglobulin M from immunoglobulin G antibodies by using reorienting gardients in vertical rotors

The parameters for the use of reorienting gradients in vertical rotors for rapid separation of immunoglobulin M from immunoglobulin G on a preparative scale for the rapid diagnosis of infectious diseases are described.

Alcohol dehydrogenase from Methylobacterium organophilum

The alcohol dehydrogenase from Methylobacterium organophilum, a facultative methane-oxidizing bacterium, has been purified to homogeneity as indicated by sodium dodecyl sulfate-gel electrophoresis. It has several properties in common with the alcohol dehydrogenases from other methylotrophic bacteria. The active enzyme is a dimeric protein, both subunits having molecular weights of about 62,000. The enzyme exhibits broad substrate specificity for primary alcohols and catalyzes the two-step oxidation of methanol to formate. The apparent Michaelis constants of the enzyme are 2.9 x 10(-5) M for methanol and 8.2 x 10(-5) M for formaldehyde. Activity of the purified enzyme is dependent on phenazine methosulfate. Certain characteristics of this enzyme distinguish it from the other alcohol dehydrogenases of other methylotrophic bacteria. Ammonia is not required for, but stimulates the activity of newly purified enzyme. An absolute dependence on ammonia develops after storage of the purified enzyme. Activity is not inhibited by phosphate. The fluorescence spectrum of the enzyme indicates that it and the cofactor associated with it may be chemically different from the alcohol dehydrogenases from other methylotrophic bacteria. The alcohol dehydrogenases of Hyphomicrobium WC-65, Pseudomonas methanica, Methylosinus trichosporium, and several facultative methylotrophs are serologically related to the enzyme purified in this study. The enzymes of Rhodopseudomonas acidophila and of organisms of the Methylococcus group did not cross-react with the antiserum prepared against the alcohol dehydrogenase of M. organophilum.