Use of autonomous audio recordings for the rapid inventory of birds in the white‐sand forests of the Peruvian Amazon

White‐sand forests are patchily distributed ecosystems covering just 5% of Amazonia that host many specialist species of birds not found elsewhere, and these forests are threatened due to their small size and human exploitation of sand for construction projects. As a result, many species of birds that are white‐sand specialists are at risk of extinction, and immediate conservation action is paramount for their survival. Our objective was to evaluate current survey methods and determine the relative effect of the size of patches of these forests on the presence or absence of white‐sand specialists. Using point counts and autonomous recorders, we surveyed avian assemblages occupying patches of white‐sand forest in the Peruvian Amazon in April 2018. Overall, we detected 126 species, including 21 white‐sand forest specialists. We detected significantly more species of birds per survey point with autonomous recorders than point counts. We also found a negative relationship between avian species richness and distance from the edge of patches of white‐sand forest, but a significant, positive relationship when only counting white‐sand specialists. Although we detected more species with autonomous recorders, point counts were more effective for detecting canopy‐dwelling passerines. Therefore, we recommend that investigators conducting surveys for rare and patchily distributed species in the tropics use a mixed‐method approach that incorporates both autonomous recorders and visual observation. Finally, our results suggest that conserving large, continuous patches of white‐sand forest may increase the likelihood of survival of species of birds that are white‐sand specialists.     

Molecular Forms of Acetylcholinesterase and Butyrylcholinesterase in Human Plasma and Cerebrospinal Fluid

The measurement of cholinesterase activities in either plasma or cerebrospinal fluid (CSF) may ultimately prove to be relevant in the diagnosis of neurological and neuropsychiatric disorders. However, studies to date have examined only total enzyme activities. Therefore in the present study we have examined the distribution of the individual molecular forms of both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in plasma and CSF using sucrose density gradient centrifugation. Although the total activities of AChE were of the same order of magnitude in plasma and CSF, there was a considerable difference (120-500-fold) between total BChE activity in the CSF and the BChE-rich plasma. The analysis of the individual molecular forms revealed that the predominant molecular species of AChE and BChE in the CSF--both lumbar and ventricular--was the G4 form. The G4 form also constituted the majority of the plasma BChE activity and, on average, over half (56%) of the plasma AChE activity. The significance of the AChE and BChE molecular form compositions of both plasma and CSF and their possible relationship to pathological states are discussed.     

The impact of different fixation procedures on staining of macromolecules in a microtiter system

Summary The effects of formaldehyde, glutaraldehyde, methanol, Clarke's fixative and microwave irradiation on the quantitative staining of proteins (Naphthol Yellow S) and nucleic acids (Ethyl Green—Pyronin) in a cell culture system have been investigated. Overall, glutaraldehyde rapidly yielded the highest and most consistent levels of staining when compared to all other chemical fixatives. Although microwave irradiation was found to be uneven, 4 min exposure to 700W was found to give higher levels of protein staining than those achieveable with glutaraldehyde. Time-dependent processes were observed with all procedures. In addition, dissociations in the trends of protein and nucleic acid staining were observed. It is suggested that these results domonstrate fixation events that have not previously been resolved from the effects of reagent penetration into tissue blocks.     

Transport of an Mr approximately 300,000 Plasmodium falciparum protein (Pf EMP 2) from the intraerythrocytic asexual parasite to the cytoplasmic face of the host cell membrane

The profound changes in the morphology, antigenicity, and functional properties of the host erythrocyte membrane induced by intraerythrocytic parasites of the human malaria Plasmodium falciparum are poorly understood at the molecular level. We have used mouse mAbs to identify a very large malarial protein (Mr approximately 300,000) that is exported from the parasite and deposited on the cytoplasmic face of the erythrocyte membrane. This protein is denoted P. falciparum erythrocyte membrane protein 2 (Pf EMP 2). The mAbs did not react with the surface of intact infected erythrocytes, nor was Pf EMP 2 accessible to exogenous proteases or lactoperoxidase-catalyzed radioiodination of intact cells. The mAbs also had no effect on in vitro cytoadherence of infected cells to the C32 amelanotic melanoma cell line. These properties distinguish Pf EMP 2 from Pf EMP 1, the cell surface malarial protein of similar size that is associated with the cytoadherent property of P. falciparum-infected erythrocytes. The mAbs did not react with Pf EMP 1. In one strain of parasite there was a significant difference in relative mobility of the 125I-surface-labeled Pf EMP 1 and the biosynthetically labeled Pf EMP 2, further distinguishing these proteins. By cryo-thin-section immunoelectron microscopy we identified organelles involved in the transit of Pf EMP through the erythrocyte cytoplasm to the internal face of the erythrocyte membrane where the protein is associated with electron-dense material under knobs. These results show that the intraerythrocytic malaria parasite has evolved a novel system for transporting malarial proteins beyond its own plasma membrane, through a vacuolar membrane and the host erythrocyte cytoplasm to the erythrocyte membrane, where they become membrane bound and presumably alter the properties of this membrane to the parasite's advantage.