Annexin II enhances cytomegalovirus binding and fusion to phospholipid membranes

A number of studies have suggested that the anionic phospholipid (anPL)-binding protein annexin II may play a role in cytomegalovirus (CMV) infection. Since annexin II has been shown to mediate aggregation and fusion of certain membranes, we investigated whether these properties could be exploited by CMV directly. The experiments showed that purified annexin II, but not the homologous protein annexin V (AnV), can mediate the binding of 35S-CMV (strain AD169) to anPL-coated microtiter wells. This association required Ca2+, could be titrated by varying either annexin II (apparent Kd = 4 x 10(-)8 M) or 35S-CMV, was inhibited by unlabeled CMV, and was observed for the heterotetrameric or monomeric form of annexin II. In experiments utilizing the fluorescence dequenching of octadecyl rhodamine incorporated into the CMV envelope, annexin II was furthermore found to enhance the rate of virus-anPL vesicle fusion. The observed fusion was dependent on the concentration of annexin II, Ca2+, and anPL and was mediated principally by the heterotetramer. Interestingly, AnV was observed to inhibit the effects of annexin II on CMV fusion but not binding to anPL, which indicates that annexin II enhances these processes by distinct mechanisms. The results presented here provide the first direct evidence that annexin II has the capacity to bridge CMV to a phospholipid membrane and to enhance virus-membrane fusion. These observations furthermore suggest that AnV may regulate the fusogenic function of annexin II.     

Fluorescence microscopy of mycobacteria in pleural effusions

The diagnostic advantage of fluorescence microscopy (FM) of Papanicolaou-stained cytological specimens obtained by bronchoscopy has been described previously. This study was designed to evaluate the method's diagnostic benefit in cytological preparations of pleural effusions in cases of active pulmonary tuberculosis. In contrast to bronchial material there is no advantage in cytological evaluation of pleural effusions by FM.     

Cloning and characterization of SK2 channel from chicken short hair cells

In the inner ear of birds, as in mammals, reptiles and amphibians, acetylcholine released from efferent neurons inhibits hair cells via activation of an apamin-sensitive, calcium-dependent potassium current. The particular potassium channel involved in avian hair cell inhibition is unknown. In this study, we cloned a small-conductance, calcium-sensitive potassium channel (gSK2) from a chicken cochlear library. Using RT-PCR, we demonstrated the presence of gSK2 mRNA in cochlear hair cells. Electrophysiological studies on transfected HEK293 cells showed that gSK2 channels have a conductance of approximately 16 pS and a half-maximal calcium activation concentration of 0.74±0.17 M. The expressed channels were blocked by apamin (IC₅₀=73.3±5.0 pM) and d-tubocurarine (IC₅₀=7.6±1.0 M), but were insensitive to charybdotoxin. These characteristics are consistent with those reported for acetylcholine-induced potassium currents of isolated chicken hair cells, suggesting that gSK2 is involved in efferent inhibition of chicken inner ear. These findings imply that the molecular mechanisms of inhibition are conserved in hair cells of all vertebrates.     

Electron spin resonance of some bacterial respiratory membranes

Electron spin resonance measurements have been carried out on extracts from eight different bacterial respiratory membranes. The available evidence suggests that the copper is probably associated with the terminal cytochromes. From the Fe^3* (g=4.3) signal, copper: cytochrome ratios and the absence of any detectable copper in the ESR spectra at 77° K under varying oxidation and reduction conditions, it is concluded that most of the copper in the membranes is paired with other coppers or more probably with a high-spin ferric ion with the copper-metal distance not greater than 5 Å.     

Brain Response to Food Stimulation in Obese,Normal Weight,and Successful Weight Loss Maintainers

As many people struggle with maintenance of weight loss, the study of successful weight loss maintainers (SWLM) can yield important insights into factors contributing to weight loss maintenance. However, little research has examined how SWLM differ from people who are obese or normal weight (NW) in brain response to orosensory stimulation. The goal of this study was to determine if SWLM exhibit different brain responses to orosensory stimulation. Brain response to 1‐min orosensory stimulation with a lemon lollipop was assessed using functional magnetic resonance imaging among 49 participants, including SWLM (n = 17), NW (n = 18), and obese (n = 14) controls. Significant brain responses were observed in nine brain regions, including the bilateral insula, left inferior frontal gyrus, left putamen, and other sensory regions. All regions also exhibited significant attenuation of this response over 1 min. The SWLM exhibited greater response compared with the other groups in all brain regions. Findings suggest that the response to orosensory stimulation peaks within 40 s and attenuates significantly between 40 and 60 s in regions associated with sensation, reward, and inhibitory control. Greater reactivity among the SWLM suggests that greater sensory reactivity to orosensory stimulation, increased anticipated reward, and subsequently greater inhibitory processing are associated with weight loss maintenance.     

Amount of Food Group Variety Consumed in the Diet and Long‐Term Weight Loss Maintenance

Objective: Decreases in variety of foods consumed within high‐fat‐dense food groups and increases in variety of foods consumed within low‐fat‐dense food groups are associated with lower energy intake and greater weight loss during obesity treatment and may assist with weight loss maintenance. This study examined food group variety in 2237 weight loss maintainers in the National Weight Control Registry, who had lost 32.2 ± 18.0 kg (70.9 ± 39.5 lbs) and maintained a weight loss of at least 13.6 kg (30 lbs) for 6.1 ± 7.7 years. Research Methods and Procedures: At entry into the registry, registry members completed a food frequency questionnaire from which amount of variety consumed from different food groups was assessed. To provide a context for interpreting the level of variety occurring in the diet of registry participants, food group variety was compared between registry participants and 96 individuals who had recently participated in a behavioral weight loss program and had lost at least 7% of initial body weight. Results: Registry members reported consuming a diet with very low variety in all food groups, especially in those food groups higher in fat density. Registry participants consumed significantly (p < 0.001) less variety within all food groups, except fruit and combination foods, than recent weight losers after 6 months of weight loss treatment. Discussion: These results suggest that successful weight loss maintainers consume a diet with limited variety in all food groups. Restricting variety within all food groups may help with consuming a low‐energy diet and maintaining long‐term weight loss.