The short-term regulation of foraging in harvester ants

In the seed-eating ant Pogonomyrmex barbatus, the return ofsuccessful foragers stimulates inactive foragers to leave thenest. The rate at which successful foragers return to the nestdepends on food availability; the more food available, the morequickly foragers will find it and bring it back. Field experimentsexamined how quickly a colony can adjust to a decline in therate of forager return, and thus to a decline in food availability,by slowing down foraging activity. In response to a brief, 3-to 5-min reduction in the forager return rate, foraging activityusually decreased within 2–3 min and then recovered within5 min. This indicates that whether an inactive forager leavesthe nest on its next trip depends on its very recent experienceof the rate of forager return. On some days, colonies respondedmore to a change in forager return rate. The rapid colony responseto fluctuations in forager return rate, enabling colonies toact as risk-averse foragers, may arise from the limited intervalover which an ant can track its encounters with returning foragers.     

Structure–activity relationships of non-opioid [des-Arg7]-dynorphin A analogues for bradykinin receptors

In our earlier studies, bradykinin receptors (BRs) were identified as a potential target for the neuroexcitatory effects of dynorphin A (Dyn A) in the central nervous system (CNS), and [des-Arg⁷]-Dyn A-(4–11) (6) was discovered as a lead ligand to modulate Dyn A-(2–13) induced neuroexcitatory effects in the CNS as an antagonist. In an effort to gain insights into key structural features of the Dyn A for the BRs, we pursued further structure–activity relationships (SAR) study on the [des-Arg⁷]-Dyn A analogs and confirmed that all of the [des-Arg⁷]-Dyn A analogues showed good binding affinities at the BRs.     

Age-related changes in tactile spatial resolution from 6 to 16 years old

The aim of this study was to determine age-related changes in tactile spatial resolution from 6 to 16 years old. Two hundred and twenty-two healthy children (105 boys and 117 girls) were assessed. The tactile spatial resolution threshold was determined using a classic set of JVP domes with a procedure adapted for children. Preadolescence appears to be an important step in tactile spatial resolution since children aged between 6 and 9 years old had a worse tactile spatial resolution than older children. Both peripheral and central explanations for this improvement of tactile spatial resolution with age are considered. The authors suggest that cortical maturational processes are likely to explain the better results of older children.     

Systematization of ambiguous genitalia

Sex assignment in newborns depends on the anatomy of the external genitalia, despite this stage being the final in embryogenesis. According to the current view, the genital tubercle is the embryonic precursor of penis and clitoris. It originates from mesenchymal tissue, but mesenchymal cells are arranged across the embryonal body and do not have specific androgen receptors. The nature of the signal that initiates early derivation of the indifferent genital tubercle is unknown at present. The aims of this article are to improve surgical management of intersex disorders and investigate the development of the genital tubercle. Clinical examination of 114 females with various forms of DSD revealed ambiguous (bisexual) external genitalia in 73 patients, and 51 of them underwent feminizing surgery. Intersexuality (ambiguity) in 46,XY patients results from disruptors in the pathways of sex steroid hormones or receptors; in 46,XX females arises from excessive levels of androgens. Systematization of intersex disorders distinguishes the karyotype, gonadal morphology, and genital anatomy to provide a differential diagnosis and guide appropriate surgical management. Modified feminizing clitoroplasty with preservation of the dorsal and ventral neurovascular bundles to retain erogenous sensitivity was performed in females with severe virilization (Prader degree III-V). The outgrowth of the genital tubercle and the fusion of the urethral fold proceed in an ordered fashion; but in some cases of ambiguity, there was discordance due to different pathways. Speculation about the derivation of the genital tubercle have discussed with a literature review. The genital tubercle derives from the following 3 layers: the ectodermal glans of the tubercle, the mesodermal corpora cavernosa and the endodermal urogenital groove. According to the new hypothesis, during the indifferent stages, the 5 sacral somites have to recede from their segmentation and disintegrate: the sclerotomes form the pelvic bones, the fused myotomes follow with their genuine neurotomes and the angiotomes join to the corpora cavernosa of the genital tubercle. Sexual differentiation of external genitalia is final in gender embryogenesis, but surprisingly derivation of the indifferent genital tubercle from 5 somites occurs before gonadal and internal organs development.     

Considerations in Estimating Social and Economic Impacts of Immunotoxic Agents

To make appropriate regulatory policy decisions, the potential social and economic impacts of the policy must first be established. For environmental and occupational agents, social and economic impacts are derived from animal toxicology and, when available, human studies that serve as the base for risk-benefit analysis (RBA). Because immune function is associated with resistance to infectious disease, developing RBA for data derived from immunotoxicology studies will require determining the changes in the frequency or severity of infectious disease resulting from an exposure. Fortunately, considerable information is readily available for identifying the frequency of infectious diseases in the general population and its social and economic impacts and to assist the risk assessor when conducting RBA for immunotoxicology endpoints. The following is a brief review describing some issues in using immunotoxicity data when conducting RBA. It presents an economic methodology to determine the economic impacts of infectious diseases to society, sources where these types of information are available, and an example using a specific infectious disease, otitis media.     

A cross-disorder dosage sensitivity map of the human genome

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Schistosoma mansoni: partial characterization of enzyme(s) secreted from the preacetabular glands of cercariae.

Secretions from the preacetabular glands of cercariae of Schistosoma mansoni were collected over skin surface lipid on a warmed glass surface in a system providing a temperature gradient. Proteolytic activity of these secretions was linear with respect to the numbers of cercariae secreting. The enzyme was relatively storage stable in water or glycine-NaOH buffer. It was highly sensitive to the buffer system, glycine-NaOH buffer providing the highest proteolytic activity against Azocoll and gelatin substrates. In the glycine buffer, the pH optimum for the enzyme was 8.5–8.8; the temperature optimum was 51 C with the Q₁₀ for Azocoll hydrolysis in the range of 30–50 C approximately 2.2. Of the activity 0.4% was lost at 5 C, 1.7% at 35 C, and 100% at 60 C within 10–15 min. Two Sephadex column chromatography fractions showed proteolytic activity against Azocoll. The fraction with greatest activity was not associated with either of the two peaks of high absorbancy at 280 nm, but the lower proteolytic peak coincided with the lower absorbancy peak in the area of peptides below 10,000 MW. Calibration of the Sephadex column with proteins of known molecular weight showed the MW of the main proteolytic fraction of the secretion to be approximately 25,000–27,000.