Isolation and identification of cecropin antibacterial peptides from the extracellular matrix of the insect integument

A method for the screening and isolation of antibacterial peptides from the extracellular insect cuticle using ultrafiltration and reverse-phase high-performance liquid chromatography is presented. Using this method we were able to conveniently isolate cuticular antibacterial peptides belonging to the cecropin family in 1 day. The procedure should facilitate the rapid screening of antibacterial peptides or other bioactive peptides from extracellular matrices.     

Role of the integument in insect immunity: epicuticular abrasion and induction of cecropin synthesis in cuticular epithelial cells

When the epicuticle of a silkworm larva, Bombyx mori, was lightly abraded in the presence of live Bacillus licheniformis, Enterobacter cloacae, or bacterial cell wall components, cecropin mRNAs were detected in the underlying epithelial cells and in fat body cells remote from the abraded area. Antibacterial activity due to cecropin was detected in the matrix of the lightly abraded cuticle but not in nonabraded portions of the cuticular matrix or in the hemolymph surrounding the fat body, unless a more severe cuticular abrasion was administered. A light abrasion to a larva of the giant silkworm moth, Hyalophora cecropia, in the presence of E. cloacae also induced antibacterial activity in the abraded cuticle. These data illustrate that the ectodermally derived lepidopteran larval integument, when challenged by live bacteria or their cell wall components, mounts an immune response. Hence, the insect exoskeleton, which is often considered as an inert protective armor, is indeed actively participating in defense.     

A cuticular protein from the moulting stages of an insect

A 22 kDa peptide was purified from prepupal cuticles of 5th instar Calpodes ethlius caterpillars. It was absent earlier in the stadium and from the egg and adult, i.e. it is related to cuticle turnover rather than cuticle structure. It was present at larval and metamorphic moults, showing that it is related to moulting not just metamorphosis. The cDNA corresponding to the 22 kDa peptide was isolated by antibody screening of an epidermal cDNA expression library. Hybridization to Calpodes genomic DNA showed that the gene was present as a single copy. The deduced amino acid sequence is not like any of the sequences of cuticular structural proteins that have been published, but has a 47 amino acid sequence similar to bacteriophage T7 N-acetylmuramoyl-L-alanine amidase (34% identical, 51% similar). The amino acid sequence, the timing of expression in development, and the similarity between the substrate of the bacteriophage amidase and components of insect cuticle, all suggest that the 22 kDa protein may have a role in cleaving chitin-peptide bonds as a prerequisite for digestion of the cuticle by chitinases and proteases.     

The ultrastructure of the integument of the American eel, Anguilla rostrata

The yolk sac of the little brown bat is unusual in that during the course of gestation both the inner endodermal cells (bordering the yolk sac cavity) and outer mesothelium (facing the exocelom) form simple columnar epithelia which persist throughout gestation. These endodermal cells develop an extensive system of agranular endoplasmic reticulum, numerous lipid droplets and unusual "giant" mitochondria. During development the Golgi apparatus changes position from the apical to the basal side of the nucleus, reversing the polarity of the cells. In general, the endodermal cells have cytological features suggestive of synthetic or secretory activity. The mesothelial cells develop an extensive "absorptive apparatus" in their apices, while large crystalloid-containing granules become numerous in their basal cytoplasm. The mesothelial cells have large deposits of glycogen, especially during mid-gestation, but few mitochondria and little granular endoplasmic reticulum. Endodermal cells do not absorb exogenous protein (peroxidase) even if it is injected directly into the yolk sac cavity. However, placement of peroxidase either in the exocelom or in the maternal vascular system results in the appearance of this protein in the "absorptive apparatus" of mesothelial cells as well as in macrophages in the stroma of the yolk sac. While evidence of absorption was clear, no direct evidence of transport of tracer to fetal blood vascular system was obtained. It is postulated that a major function of the hypertrophied mesothelial cells during gestation is the absorption of proteins and possibly other substances from the exocelomic fluid. The major function of the hypertrophied endodermal cells may be synthesis and secretion of substances into the fetal circulation.     

A developmental study of recall from natural categories.

27 6th graders, 25 college students, and 26 older adults (aged 57–77 yrs) were asked to list exemplars from the semantic domains of animals and occupations for 6 min each. Cumulative recall curves were found to fit a hyperbolic model of recall and to be stable over age in the animal domain; in the occupation domain, 6th graders reached asymptote earlier. A slope-difference algorithm was used to identify clusters within recall. It was found that the size of clusters was stable over time. Older adults tended to find new clusters at a faster rate in the later stages of recall, and the youngest and oldest Ss reported items within clusters at a slower rate. Results demonstrate the stability of some basic functions in semantic memory and support a production deficiency view of reported deficits in episodic memory tasks. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Traits as goal-based categories: The importance of goals in the coherence of dispositional categories.

It is argued that goals are central to the meaning and structure of many traits and help define the prototypicality structure of those traits. Partly on the basis of L. W. Barsalou's (1985) work on goal-derived categories, it was predicted that goals help define the judged prototypicality of many trait-related behaviors and the confidence with which people make trait inferences from those behaviors. Consistent with this hypothesis, ratings of the extent to which behaviors achieved the goal associated with a trait strongly predicted the typicality of the behaviors. Furthermore, the rated goal-relatedness of a behavior also strongly predicted the confidence with which people would make a trait inference from that behavior. It is suggested that goals play a major role in the conceptual coherence of traits and other social categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of memory decay on predictions from changing categories.

In contrast to the static categories assumed in most categorization experiments, many real-world categories undergo gradual and systematic change in their definitions over time. Four experiments were carried out to study such category change. In these studies, participants successfully adjusted as category change occurred, but also showed a lingering and cumulative effect of past observations. The participants' performance was closely modeled by incorporating memory decay for past observations into J. R. Anderson's (1990, 1991) rational categorization algorithm and into a version of R. M. Nosofsky's (1986) exemplar categorization model. The resulting models suggest that the decay function is closer to a power law than to an exponential and that decay occurs both by item and by time, with the item decay being stronger than the time decay. The finding of power law decay gives additional support to claims that exemplar memories are used in categorization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In vivo localization of diglycylcysteine-bearing synthetic peptides by nuclear imaging of oxotechnetate transchelation

The goal of this study was to propose a new approach of the upper tibia for intramedullary nailing. Since two years, the authors performed a transversal skin incision superior to the distal end of the patella. The patellar tendon is dissociated and the tibia is perforated through the anterior intercondylar area. The advantages of this approach versus classical techniques are discussed. This approach allows isolated tibial or femoral nailing but also both nailings during the same procedure.     

Immunohistological localization of regulatory peptides in the midgut of the female mosquito Aedes aegypti

The midgut of the female mosquito Aedes aegypti was studied immunohistologically with antisera to various regulatory peptides. Endocrine cells immunoreactive with antisera to perisulfakinin, RFamide, bovine pancreatic polypeptide, urotensin 1, locustatachykinin 2 and allatostatins A1 and B2 were found in the midgut. Perisulfakinin, RFamide and bovine pancreatic polypeptide all react with the same, about 500 endocrine cells, which were evenly distributed throughout the posterior midgut, with the exception of its most frontal and caudal regions. In addition, these antisera recognized three to five neurons in each ingluvial ganglion and their axons, which ran longitudinally over the anterior midgut, as well as axons innervating the pyloric sphincter. The latter axons appear to be derived from neurons located in the abdominal ganglia. Antisera to two different allatostatins recognized about 70 endocrine cells in the most caudal area of the posterior midgut and axons in the anterior midgut whose cell bodies were probably located in either the brain or the frontal ganglion. Antiserum to locustatachykinin 2 recognized endocrine cells present in the anterior midgut and the most frontal part of the posterior midgut, as well as about 50 cells in the most caudal region of the posterior midgut. Urotensin 1 immunoreactivity was found in endocrine cells in the same region as the perisulfakinin-immunoreactive cells, but no urotensin-immunoreactive axons were found in the midgut. Double labeling experiments showed that the urotensin and perisulfakinin immunoreactivities were located in different cells. Such experiments also showed that the locustatachykinin and allatostatin immunoreactivities in the most caudal area of the posterior midgut were present in different cells. No immunoreactivity was found in the mosquito midgut when using antisera to corazonin, allatropin or leucokinin IV. Since these peptides have either been isolated from, or can reasonably be expected to be present in mosquitoes, it was concluded that these peptides are not present in the mosquito midgut.     

Immunohistochemical localization of novel CART peptides in rat hypothalamus, pituitary and adrenal gland

CART peptide specific polyclonal antisera were raised in rabbits. The antisera were raised to CART peptide fragments that span most of the predicted CART protein. The specificity of each antisera was demonstrated by blockade of immunostaining by the immunizing peptide but not by the other CART peptide fragments. In the hypothalamus and pituitary of colchicine and noncolchicine treated rats, immunostaining was observed in cell bodies, fibers and varicosities. Clusters of cells were also stained in the adrenal medulla. It is noteworthy that cellular immunostaining was only found in areas previously shown to express CART mRNA. These findings indicate the presence of CART peptide(s) in the hypothalamus, pituitary, and adrenal gland. Furthermore, we also present evidence for the possible processing of the CART pro-peptide into smaller peptide fragments. These neuroanatomical findings suggest a role of CART peptides in hypothalamic, pituitary and adrenal function.     

The novel cuticular collagen Ovcol-1 of Onchocerca volvulus is preferentially recognized by immunoglobulin G3 from putatively immune individuals

The concentration and affinity to concanavalin A (ConA) of plasma alpha 1-acid glycoprotein (AGP) and AGP levels in extracts of liver tissues were investigated in specific-pathogen-free chickens infected with the highly virulent HPS-2 strain or virulent reference GBF-1 strain of infectious bursal disease virus. The plasma AGP value in uninfected control 3- to 7-wk-old chickens was 161.8 +/- 25.8 micrograms/ml (mean +/- SD), and ConA-unreactive and ConA-reactive AGP comprised 47% and 63% of total AGP. Increases in AGP levels in plasma and liver extracts were observed in both the HPS-2 and the GBF-1 groups, although albumin levels decreased. The plasma AGP values were higher in the HPS-2 group than in the GBF-1 group through the experimental period. In the HPS-2 group, ConA-reactive AGP reached levels 6.8-fold greater than control values and comprised 80% of total AGP at 4 days post-inoculation. In the lipopolysaccharide group, a great increase in ConA-reactive AGP was observed.     

Similar and different: The differentiation of basic-level categories.

Categories in the middle level of a taxonomic hierarchy tend to be highly differentiated in that they have both high levels of within-category similarity and low levels of between-category similarity. Research on similarity reveals a distinction between pairs of categories that are seen as dissimilar because they have few commonalities and pairs that are seen as dissimilar because they have many psychologically relevant alignable differences. The authors suggest that the low between-category similarity proposed for neighboring basic-level categories is actually a matter of having many psychologically relevant differences. In contrast, the low between-category similarity of superordinates is a result of their having few commonalities. The authors evaluate this claim in 4 experiments using a variety of natural stimuli and converging measures. The data support the importance of alignable differences for distinguishing between pairs of basic-level categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The amino-acid sequence of the three smallest CNBr peptides from p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens

After CNBr cleavage of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens, five peptides and free homoserine were isolated (see preceding paper in this journal). The amino acid sequences of the three smallest peptides, viz. CB3, CB4 and CB5, were determined by automated Edman degradation and analysis of enzymatic subdigests. These peptides form a continuous stretch of 110 residues from the N terminus: (Formula: See Text).     

Sequence studies on post-ecdysial cuticular proteins from pupae of the yellow mealworm, Tenebrio molitor

Preischemic adrenergic stimulation may affect postischemic cardiac function. Using an isolated working heart model, we investigated the effects of preischemic catecholamine treatment on postischemic recovery. Hearts from Wistar rats were perfused in working mode for 20 min, in Langendorff mode for 15 min, and again in working mode for 20 min (W2). Hearts were treated with isoproterenol (8.0 and 40.0 nmol/L), phenylephrine (0.06, 0.30, and 1.50 micromol/L), or epinephrine (16 and 80 nmol/L) during the W2 period and then arrested with St Thomas' Hospital cardioplegic solution (STH) and subjected to global ischemia (37 degrees C or 20 degrees C), followed by reperfusion. At 37 degrees C, isoproterenol had a beneficial effect at the lower dose but a harmful effect at the higher dose; phenylephrine and epinephrine had a harmful effect at all doses. At 20 degrees C, isoproterenol and epinephrine had a harmful effect at a high dose; phenylephrine had no harmful effect at any dose. In a separate study, the influence of calcium modulators (diltiazem and ryanodine, added in the STH) on the catecholamine effect was investigated. The harmful effect of preischemic treatment with isoproterenol (24.0 nmol/L) or phenylephrine (0.9 micromol/L) was abolished by the calcium modulators. Thus, preischemic beta-adrenergic or alpha + beta-adrenergic stimulation has a deleterious effect on postischemic recovery of the myocardium. The effect could be altered depending on the subtype and dose of catecholamine and the ischemic temperature. Intracellular calcium movement could be involved in the mechanism responsible for the harmful effect of preischemic catecholamine treatment.     

Attentional requirements for the selection of words from different grammatical categories.

Two grammatical classes are commonly distinguished in psycholinguistic research. The open-class includes content words such as nouns, whereas the closed-class includes function words such as determiners. A standing issue is to identify whether these words are retrieved through similar or distinct selection mechanisms. We report a comparative investigation of the allocation of attentional resources during the retrieval of words from these 2 classes. Previous studies used a psychological-refractory-period paradigm to establish that open-class word retrieval is supported by central attention mechanisms. We applied the same logic to closed-class word retrieval. French native speakers named pictures with determiner noun phrases while they concurrently identified the pitch of an auditory tone. The ease of noun and determiner retrieval was manipulated independently. Results showed that both manipulations affected picture naming and tone discrimination responses in similar ways. This suggests the involvement of central attentional resources in word production, irrespective of word class. These results argue against the commonly held hypothesis that closed-class retrieval is an automatic consequence of syntactic specific processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classifying faces by race: The structure of face categories.

This article explored the finding that cross-race (CR) faces are more quickly classified by race than same race (SR) faces. T. Valentine and M. Endo (1992) modeled this effect by assuming that face categories can be explained on the basis of node activations in a multidimensional exemplar space. Therefore, variations in exemplar density between and within face categories explain both facilitated classification of CR faces and the relationship between typicality and classification RT within face categories. The present findings from classification and visual search tasks suggest that speeded classification of CR faces is instead caused by a quickly coded race feature that marks CR but not SR faces. Also, systematic manipulations of facial typicality cause no variation in classifiability aside from slowed classification of very distinctive faces. These results suggest that the exemplar model cannot explain important aspects of face classification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emergence of action categories in the child: Evidence from verb meanings.

In adults, action categories encompass 2 kinds of instances: self-action and observed action. This article proposes a model of how adult action categories emerge in children whose early categories are specific to self- or observed action. The model posits that these categories are extended to encompass both kinds of instances as children develop the ability to note parallels between themselves and others as initiators of action. For adults, these parallels involve goals, causal efficacy, and movement. It is argued that parallels involving movement, which are directly observable, would be noted first and that parallels involving causes and goals, which are not directly observable and require inferences about internal states of other people, would be noted only later. Three studies of children's verb meanings were carried out to examine the development of action categories and to evaluate the proposed model. 103 preschoolers served as Ss. Findings show that verbs first encode children's own actions and only later encode the observed actions of other people. Further, verbs that encode characteristic movements (e.g., "walk") are extended to encompass observed action earlier than verbs that encode change (e.g., "open"), supporting the proposed model. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunohistochemical localization of epidermal growth factor receptors, epidermal-growth-factor-like and transforming-growth-factor-alpha-like peptides in chicken ovarian follicles

The purpose of this study was to determine the presence of epidermal growth factor receptor and its potential ligands epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha) in the tissues of the maturing follicles in the ovary of laying ISA-Brown hens using peptide-specific immunohistochemical methods. Cryostat sections, 6-8 microns thick, were made from fresh-frozen tissues of F1-F4 (largest to fourth largest) and large white follicles and they were immunostained for epidermal growth factor receptor, epidermal growth factor or transforming growth factor alpha using specific polyclonal antibodies. The EGF receptor and both ligands were detected in the granulosa, theca interna and theca externa layers of the follicles. The EGF receptor was localized both in the plasma membrane and cytoplasm of all cell types. EGF was predominantly cytosolic, whereas TGF-alpha was found in the plasma membranes and perinuclear areas of all cell types. The concentration of the receptor and both ligands decreased with follicular maturation. This observation is consistent with our previous observation that the response to EGF and TGF-alpha decreases as follicles mature, and thus provides further evidence that the receptor or the ligands may have a regulatory role in avian ovarian function.