Polyethylene glycol precipitation for recovery of pathogenic viruses, including hepatitis A virus and human rotavirus, from oyster, water, and sediment samples.

Polyethylene glycol 6000 precipitation was found to be an effective concentration method that enhanced the chances for detecting human virus pathogens in environmental samples. Percent recoveries from eluates of fresh and estuarine waters with 8% polyethylene glycol 6000 averaged 86 for hepatitis A virus, 77 for human rotavirus Wa, 87 for simian rotavirus SA11, and 68 for poliovirus. Percent recoveries of 97, 40, 97 and 105, respectively, for the same viruses were obtained from oyster eluates by the same procedure. Percent recoveries of 97 for hepatitis A virus and 78 for human rotavirus Wa were obtained from sediment eluates containing 2 M NaNO3 with a final concentration of 15% polyethylene glycol 6000. The polyethylene glycol method was shown to be more effective than the organic flocculation method for recovery of hepatitis A virus and rotaviruses Wa and SA11, but not of poliovirus 1 in laboratory studies. In field trials, hepatitis A virus or rotavirus or both were recovered from 12 of 18 eluates by polyethylene glycol, compared with recovery from 9 of 18 eluates by organic flocculation from fresh and estuarine waters subject to pollution.     

A two-step procedure for purification of papain from extract of papaya latex

A method is presented for purifying papain from extracts of papaya latex. The procedure involves precipitation of the extract of papaya latex with sodium chloride followed by affinity chromatography of the redissolved precipitate. Precipitation of the protein from the latex extract is necessary to separate the papain from material which interferes with the binding of papain to the affinity column. During affinity chromatography, the affinity column is overloaded to insure absence in the final product of impurities which are capable of binding to the affinity column.The papain prepared by this procedure yielded an amino acid analysis and an N-terminal amino acid analysis expected for a sample of pure papain. No Met was detected on amino acid analysis nor was the presence of N-terminal residues other than He detected. On polyacrylamide disc gel electrophoresis at pH 4.3, papain prepared by the method described in this work was indistinguishable from crystalline papain which was prepared by the method of Kimmel and Smith, and further purified by affinity chromatography. Both disc gel patterns consisted of a single band and a trailing shadow which was less than 5% of the main band. In routine spectrophotometric assays, the specific activity toward N,α-benzoyl-l-arginine ethyl ester of papain prepared by the procedure described in this work was indistinguishable from crystalline papain prepared by the method of Kimmel and Smith, and further purified by affinity chromatography. Values of 24 sec^?1' and 15 mm were obtained from the turnover number and K_m for the papain-catalyzed hydrolysis of N,α-benzoyl-l-arginine ethyl ester at 25 °C, pH 6.00, $\text{Γ}\text{2 0.30}$ using a pH stat.     

Absorption and metabolism of nicotine from cigarettes.

Eight men volunteers each smoked a single cirgarette containing 14C-nicotine and gave arterial blood samples during and for 50 minutes after smoking. The maximum concentration of nicotine in the arterial blood ranged from 31 to 41 mug/l in four regular cigarette smokers who inhaled. Two non-smokers achieved maximum levels of 2 and 4 mug/l. On a separate occasion two of the inhalers received 1 mg. 14C-nicotine in 10 divided doses injected intravenously. In both cases the peak arterial nicotine concentrations bore a similar relationship to the intravenous dose, as did the peak nicotine concentrations to the retained doses during smoking.     

Species identity of insect cell lines

Summary Three mosquito cell cultures designated as Suitor's clone ofAedes aegypti, Culiseta inornata andAedes vexans were shown to be moth by immunological, karyological, and isozyme analyses. The cells reacted with rabbit antimoth serum but not rabbit antimosquito serum. Chromosome analyses indicated Lepidopteran rather than Dipteran morphology, and three isozyme systems were confirmative. Any one of these assays would be sufficient to indicate that contamination had occurred and could be used as a periodic check for identity of cell cultures. Morphology and growth characteristics are also valid criteria to distinguish between these particular orders of insect cells. These studies were supported by Grant CA-04953-12 from the National Cancer Institute; General Research Support Grant FR-5582 from the National Institues of Health; and Grant-in-Aid Contract M-43 from the State of New Jersey. Recipient of Research Career Award 5-K3-16,749. from the National Institutes of Health.     

Ubiquitin-conjugating Enzyme Cdc34 and Ubiquitin Ligase Skp1-Cullin-F-box Ligase (SCF) Interact through Multiple Conformations

In the ubiquitin-proteasome system, protein substrates are degraded via covalent modification by a polyubiquitin chain. The polyubiquitin chain must be assembled rapidly in cells, because a chain of at least four ubiquitins is required to signal for degradation, and chain-editing enzymes in the cell may cleave premature polyubiquitin chains before achieving this critical length. The ubiquitin-conjugating enzyme Cdc34 and ubiquitin ligase SCF are capable of building polyubiquitin chains onto protein substrates both rapidly and processively; this may be explained at least in part by the atypically fast rate of Cdc34 and SCF association. This rapid association has been attributed to electrostatic interactions between the acidic C-terminal tail of Cdc34 and a feature on SCF called the basic canyon. However, the structural aspects of the Cdc34-SCF interaction and how they permit rapid complex formation remain elusive. Here, we use protein cross-linking to demonstrate that the Cdc34-SCF interaction occurs in multiple conformations, where several residues from the Cdc34 acidic tail are capable of contacting a broad region of the SCF basic canyon. Similar patterns of cross-linking are also observed between Cdc34 and the Cul1 paralog Cul2, implicating the same mechanism for the Cdc34-SCF interaction in other members of the cullin-RING ubiquitin ligases. We discuss how these results can explain the rapid association of Cdc34 and SCF.     

Population status and habitat occupancy of endangered river dolphins in the Karnali River system of Nepal during low water season

Ganges river dolphin abundance has undergone a predominant decline across its range since monitoring began. In Nepal, disappearance from some of the rivers it once used has already occurred. Today this species can only be found in three river systems in Nepal, the Karnali, Sapta Koshi, and Narayani, but numbers are low in these locations. To determine the abundance of dolphins remaining in the Karnali system (which includes the Karnali, Geruwa, and Mohana), and factors affecting dolphin habitat use, we conducted surveys where we recorded dolphin presence. Dolphins within this river system were sighted only in the Karnali and an abundance estimate of 5.04 ± 0.753 SE was calculated. This pattern of ranging differed from that previously reported (from previous sightings only in the Geruwa to current sightings only in the Karnali). River depth likely contributed to the presence or absence of dolphins. Shifts in available habitat between the Geruwa and Karnali have resulted from changes in the course of the main stream Karnali following construction of the Chisapani irrigation intake. Because of the low numbers of dolphins reported, there is great concern that loss of this species in Nepal is likely in the near future.     

A Framework for Understanding and Generating Integrated Solutions for Residential Peak Energy Demand

Supplying peak energy demand in a cost effective, reliable manner is a critical focus for utilities internationally. Successfully addressing peak energy concerns requires understanding of all the factors that affect electricity demand especially at peak times. This paper is based on past attempts of proposing models designed to aid our understanding of the influences on residential peak energy demand in a systematic and comprehensive way. Our model has been developed through a group model building process as a systems framework of the problem situation to model the complexity within and between systems and indicate how changes in one element might flow on to others. It is comprised of themes (social, technical and change management options) networked together in a way that captures their influence and association with each other and also their influence, association and impact on appliance usage and residential peak energy demand. The real value of the model is in creating awareness, understanding and insight into the complexity of residential peak energy demand and in working with this complexity to identify and integrate the social, technical and change management option themes and their impact on appliance usage and residential energy demand at peak times.     

Vascular Factors and Multiple Measures of Early Brain Health: CARDIA Brain MRI Study

Objective

To identify early changes in brain structure and function that are associated with cardiovascular risk factors (CVRF).

Design

Cross-sectional brain Magnetic Resonance I (MRI) study.

Setting

Community based cohort in three U.S. sites.

Participants

A Caucasian and African-American sub-sample (n= 680; mean age 50.3 yrs) attending the 25 year follow-up exam of the Coronary Artery Risk Development in Young Adults Study.

Primary and Secondary Outcomes

3T brain MR images processed for quantitative estimates of: total brain (TBV) and abnormal white matter (AWM) volume; white matter fractional anisotropy (WM-FA); and gray matter cerebral blood flow (GM-CBF). Total intracranial volume is TBV plus cerebral spinal fluid (TICV). A Global Cognitive Function (GCF) score was derived from tests of speed, memory and executive function.

Results

Adjusting for TICV and demographic factors, current smoking was significantly associated with lower GM-CBF and TBV, and more AWM (all <0.05); SA with lower GM-CBF, WM-FA and TBV (p=0.01); increasing BMI with decreasing GM-CBF (p<0003); hypertension with lower GM-CBF, WM-FA, and TBV and higher AWM (all <0.05); and diabetes with lower TBV (p=0.007). The GCS was lower as TBV decreased, AWM increased, and WM-FA (all p<0.01).

Conclusion

In middle age adults, CVRF are associated with brain health, reflected in MRI measures of structure and perfusion, and cognitive functioning. These findings suggest markers of mid-life cardiovascular and brain health should be considered as indication for early intervention and future risk of late-life cerebrovascular disease and dementia.