Increased demand for NAD+ relative to ATP drives aerobic glycolysis

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Chimpanzee feeding ecology and fallback food use in the montane forest of Nyungwe National Park,Rwanda

Almost all primates experience seasonal fluctuations in the availability of key food sources. However, the degree to which this fluctuation impacts foraging behavior varies considerably. Eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda, live in a montane forest environment characterized by lower primary productivity and resource diversity than low‐elevation forests. Little is known about chimpanzee feeding ecology in montane forests, and research to date predominantly relies on indirect methods such as fecal analyses. This study is the first to use mostly observational data to examine how seasonal food availability impacts the feeding ecology of montane forest chimpanzees. We examine seasonal changes in chimpanzee diet and fallback foods (FBFs) using instantaneous scan samples and fecal analyses, supported by inspection of feeding remains. Chimpanzee fruit abundance peaked during the major dry season, with a consequent change in chimpanzee diet reflecting the abundance and diversity of key fruit species. Terrestrial herbaceous vegetation was consumed throughout the year and is defined as a “filler” FBF. In contrast to studies conducted in lower‐elevation chimpanzee sites, figs (especially Ficus lutea) were preferred resources, flowers were consumed at seasonally high rates and the proportion of non‐fig fruits in the diet were relatively low in the current study. These divergences likely result from the comparatively low environmental diversity and productivity in higher‐elevation environments.     

Azide-resistant mutants in Acinetobacter calcoaceticus A2 are defective in protein secretion

Abstract Azide, an inhibitor of ATPase, and a specific inhibitor of protein export was used in order to select for protein secretion mutants in Acinetobacter calcoaceticus A2. Two such mutants were isolated that were azide-resistant and defective in the general protein transport system. The mutation also conferred additional phenotypic changes, including an inability to grow on minimal media or at 40°C. The existence of protein secretion mutants with a selectable phenotype may be useful for the genetic study of protein export.     

Structural and functional variability among DQ β alleles of DR2 subtypes

Homozygous lymphoblastoid cell lines representing various Dw subtypes of DR2 were examined for polymorphism at the DQ locus by molecular and cellular techniques. The subtypes studied included Dw2, Dw12, and a group heterogenous by cellular typing that we shall refer to as non-Dw2/non-Dw12. Restriction fragment length polymorphism analysis of cell lines representing these subtypes revealed DQ -specific patterns consistent with cellular typing. Two-dimensional gel electrophoresis of DQ molecules from representative cell lines revealed a structural polymorphism of DQ among the three subtypes. The DQ chain migrated to a position that was unique to each subtype and was consistent among various representative cell lines of each subtype. Nucleotide sequence analysis of cDNA clones of DQ from Dw2, Dw12, and non-Dw2/non-Dw12 lines confirmed that the variability resided at the genetic level. Variability was found in the form of numerous scattered nucleotide substitutions throughout the first domain of these alleles. The DQ gene of the non-Dw2/non-Dw12 cell line AZH was further found to be almost identical with the DQ gene of a DR1 line (Bell et al. 1985b), implicating a common evolutionary origin of these alleles. The only difference between these two sequences was due to an apparent gene conversion event at amino acid 57. T-cell cloning experiments resulted in the derivation of Epstein-Barr virus-specific, DQw1-restricted clones that proliferated against only those cell lines that exhibited the DQ gene common to AZH and the DR1 cell line. Thus, the polymorphism among DQ alleles within DR2 results in subtype-specific restriction.     

Blidingia ramifera stat. nov. (Chlorophyta): a new marine alga for eastern North America

Blidingia minima var. ramifera is reported for the first time in eastern North America. It occurs in the Gulf of St. Lawrence, Nova Scotia and in Maine. In the estuary of the West and Rights Rivers (Antigonish Harbour, Nova Scotia) it is the most common intertidal alga and during its maximum growth period (June-August) covers 75–90% of the intertidal zone for several km of shoreline at the mouth of the Rights River. In culture, spore germination and early development were typical of the taxon as described from Europe. The taxon is raised to specific status as Blidingia ramifera stat. nov. Blidingia subsalsa is confirmed from New England based on observations of spore germination in plants from Maine and Connecticut.     

N1-Methyl-2-125I-Lysergic Acid Diethylamide, a Preferred Ligand for In Vitro and In Vivo Characterization of Serotonin Receptors

Methylation of 2-125I-lysergic acid diethylamide (125I-LSD) at the N1 position produces a new derivative, N1-methyl-2-125I-lysergic acid diethylamide (125I-MIL), with improved selectivity and higher affinity for serotonin 5-HT2 receptors. In rat frontal cortex homogenates, specific binding of 125I-MIL represents 80-90% of total binding, and the apparent dissociation constant (KD) for serotonin 5-HT2 receptors is 0.14 nM (using 2 mg of tissue/ml). 125I-MIL also displays a high affinity for serotonin 5-HT1C receptors, with an apparent dissociation constant of 0.41 nM at this site. 125I-MIL exhibits at least 60-fold higher affinity for serotonin 5-HT2 receptors than for other classes of neurotransmitter receptors, with the dopamine D2 receptor as its most potent secondary binding site. Studies of the association and dissociation kinetics of 125I-MIL reveal a strong temperature dependence, with very slow association and dissociation rates at 0 degree C. Autoradiographic experiments confirm the improved specificity of 125I-MIL. Selective labeling of serotonin receptors was observed in all brain areas examined. In vivo binding studies in mice indicate that 125I-MIL is the best serotonin receptor label yet described, with the highest frontal cortex to cerebellum ratio of any serotonergic radioligand. 125I-MIL is a promising ligand for both in vitro and in vivo labeling of serotonin receptors in the mammalian brain.