Patterns of Sleeping Site and Sleeping Tree Selection by Black-and-Gold Howler Monkeys (Alouatta caraya) in Northern Argentina

International Journal of Primatology - The selection of sleeping sites and sleeping trees in nonhuman primates is related to social and ecological factors. We investigate the role of body...     

Effect of dilution rate on eicosapentaenoic acid productivity ofPhaeodactylum tricornutum utex 640 in outdoor chemostat culture

Summary Eicosapentaenoic acid (EPA) volumetric productivity from an outdoor chemostat culture ofPhaeodactylum tricornutum UTEX 640 in a 50-l tubular photobioreactor varies with dilution rate, reaching a maximum of 47.8 mg l^–1 d^–1 at D=0.36 d^–1. Continuous culture at high dilution rates' is proposed as the most adequate operating mode to maximize polyunsaturated fatty acid production.     

Using FTA® cards to store avian blood samples for genetic studies. Their application in sex determination

FTA® cards were used for long‐term storage of avian blood samples. Blood DNA was extracted by a simple method and used in PCR for sex identification of adult and nestling Great Grey Shrikes Lanius excubitor.     

Plasma Biomarkers Discriminate Clinical Forms of Multiple Sclerosis

Multiple sclerosis, the most common cause of neurological disability in young population after trauma, represents a significant public health burden. Current challenges associated with management of multiple sclerosis (MS) patients stem from the lack of biomarkers that might enable stratification of the different clinical forms of MS and thus prompt treatment for those patients with progressive MS, for whom there is currently no therapy available. In the present work we analyzed a set of thirty different plasma cytokines, chemokines and growth factors present in circulation of 129 MS patients with different clinical forms (relapsing remitting, secondary progressive and primary progressive MS) and 53 healthy controls, across two independent cohorts. The set of plasma analytes was quantified with Luminex xMAP technology and their predictive power regarding clinical outcome was evaluated both individually using ROC curves and in combination using logistic regression analysis. Our results from two independent cohorts of MS patients demonstrate that the divergent clinical and histology-based MS forms are associated with distinct profiles of circulating plasma protein biomarkers, with distinct signatures being composed of chemokines and growth/angiogenic factors. With this work, we propose that an evaluation of a set of 4 circulating biomarkers (HGF, Eotaxin/CCL11, EGF and MIP-1β/CCL4) in MS patients might serve as an effective tool in the diagnosis and more personalized therapeutic targeting of MS patients.     

The medial basal hypothalamus and luteinizing hormone release in the rat: Where are the LH-RH neurons responsible for tonic gonadotropin secretion?

Careful review of the literature demonstrates conflicting results concerning the ability of the deafferented medial basal hypothalamus to support gonadotropin release in the rat and thus one may question the existence of LH-RH neurons in the medial basal hypothalamus. The direct search for the LH-RH perikarya in the rat hypothalamus has not settled the question of whether these releasing hormone neurons are located in the medial basal hypothalamus. Most investigators do agree that following complete hypothalamic deafferentation there is a reduction of the immunoassayable LH-RH in the medial basal hypothalamus; however, these results do not necessarily prove that LH-RH originates outside the hypothalamus. It is argued that the completely deafferented medial basal hypothalamus may be so altered by the deafferentation procedure that it may be inadequate as a means to study neuroendocrine function.     

Role of Asp-9 and Glu-36 in the active site of the pneumococcal CPL1 lysozyme: an evolutionary perspective of lysozyme mechanism.

The role of carboxylic amino acids Asp-9 and Glu-36 in the activity of CPL1 lysozyme was investigated by site-directed mutagenesis. The enzymatic activity of the single mutants D9E, D9N, D9H, D9K, D9A, E36D, E36Q, E36K, and E36A and of the double mutant D9A-E36A was analyzed using a highly sensitive radioactive assay. All mutants but D6K showed detectable activities. Interestingly, the mutants E36D and E36Q retained 67% and 37% activity, respectively. Amino acid replacements at position 9 turned out to be more critical for activity than at position 36. In analogy to the mechanism described for hen egg-white lysozyme, where the proton donor play a central role, we propose that, in the CPL1 lysozyme, Asp-9 might act as the proton donor for activation of the substrate, and Glu-36 could help in the stabilization of the intermediate oxocarbocation. The residual activity of lysozyme mutants lacking one or two of the acidic amino acids may be explained by the participation of a water molecule as proton donor and/or to electrostatic contributions in the active center stabilizing the transition state of the reaction. Our results are in agreement with the hypothesis that enzymes have been optimized during evolution from an ancestral protein able to bind more tightly the transition state of the substrate than the substrate itself, by the acquisition of amino acids serving a function in catalysis.     

Interspecific Introgression in Cetaceans: DNA Markers Reveal Post-F1 Status of a Pilot Whale

Visual species identification of cetacean strandings is difficult, especially when dead specimens are degraded and/or species are morphologically similar. The two recognised pilot whale species (Globicephala melas and Globicephala macrorhynchus) are sympatric in the North Atlantic Ocean. These species are very similar in external appearance and their morphometric characteristics partially overlap; thus visual identification is not always reliable. Genetic species identification ensures correct identification of specimens. Here we have employed one mitochondrial (D-Loop region) and eight nuclear loci (microsatellites) as genetic markers to identify six stranded pilot whales found in Galicia (Northwest Spain), one of them of ambiguous phenotype. DNA analyses yielded positive amplification of all loci and enabled species identification. Nuclear microsatellite DNA genotypes revealed mixed ancestry for one individual, identified as a post-F1 interspecific hybrid employing two different Bayesian methods. From the mitochondrial sequence the maternal species was Globicephala melas. This is the first hybrid documented between Globicephala melas and G. macrorhynchus, and the first post-F1 hybrid genetically identified between cetaceans, revealing interspecific genetic introgression in marine mammals. We propose to add nuclear loci to genetic databases for cetacean species identification in order to detect hybrid individuals.     

The Evolution of Exploitation in Humans: ‘Surrounded by Strangers I Thought Were My Friends’1

Early humans were obligately social, living in nested kin groups or close associations of related individuals. Theoretical and empirical research has demonstrated that group life is characterized by both costs (e.g. increased likelihood of disease transmission) and benefits (e.g. enhanced predator defense). This paper addresses the evolution of exploitation in humans (e.g. slavery, infanticide) as a response to within‐group competition for limiting resources (e.g. food, mates), a potential cost of living in groups. Exploitation is defined as one individual's use of another for selfish ends, in particular, the acquisition and/or use of another's resources for the optimization of inclusive fitness. It is argued that exploitation is most likely to occur in relationships characterized by asymmetries such as dependence, intimacy, and/or differential access to resources. A simple mathematical treatment assesses exploitation as a facultative response to local competition among relatives, providing insights into the conditions favorable and adverse to exploitation of conspecifics. Possible applications of the formulations are discussed, including the conditions under which intraspecific exploitation may be beneficial to both actor and recipient(s). Constraints on the evolution of exploitation in humans are identified, and suggestions are made for testing hypotheses related to the differential costs and benefits of exploitation to conspecifics. Future studies may promote the mitigation of exploitation's deleterious effects in Homo sapiens, a body of research which may apply, as well, to other social mammals.     

Hormone Effects on the Membrane Potential and on Sucrose-Induced Depolarization of Young Citrus Leaves

The effect of IAA, GA₃ and ABA on transmembrane potential difference(Em) and on sucrose-induced depolarization has been studiedin young Citrus leaves. The addition of any of these hormonesto the perfusion solution (short-term experiments) did not affectEm or sucrose-induced depolarization. Hormonal treatments ofyoung leaves on the tree resulted, after 4 to 16 days (long-termexperiments), in an increase of Em for GA₃- and ABA-treatedleaves, while in IAA-treated ones no hyperpolarization was found.Only in ABA treated leaves this membrane hyperpolarization couldbe related to an enhancement of sucrose uptake. (Received April 28, 1992; Accepted September 21, 1992)