Integration of “Innate” and “Learned” Components within the IRME for Mussel Recognition in the European Bitterling Rhodeus amarus (Bloch)

The European bitterling (Rhodeus amarus Bloch) practises a rather unusual method of spawning by using the favorable conditions in the gills of a living freshwater mussel (genera Unio and Anodonta) for the embryonic development of its fry. The capacity of mussel recognition was studied in inexperienced individuals with the aid of simultaneous preference tests in which pairs of dummies with increasing similarity to mussels were presented to the animals. The frequency of mussel-referred motor patterns, which were supposed to be species-specific (Wiepkema 1961), supplied the evaluation criterion. The results revealed a hierarchy of effectiveness within the class of relevant stimuli and showed certain effects of additivity typical of an Innate Releasing Mechanism or IRM. By far the most effective stimulus consisted in the specific smell of the mussel which is composed of at least three constituents (protein, hyaluronic acid, ammonium). The water flow itself, produced by the mussel in order to maintain nutritive and respiratory functions, was effective depending on its velocity (3 < v < 12 cm/s), its orientation (suction produced no effect), its direction (vertical > horizontal) and the shape of its field (oval). Within the visual modality only two simple perceptory patterns could be detected (dark spot on a clearer surface, straight horizontal edge), but the visual shape of the mussel as a whole was ignored by inexperienced individuals. Nevertheless the bitterlings are able to learn the shape when exposed to a living mussel and, in addition, it was even possible to condition the animals to an artificial object (inverted pot of clay) by using the mussel-smell flow as a reinforcing stimulus. The final discussion deals with the question of whether it is possible to interpret these “innate” respectively “learned” components of the IRME as sensory counterparts of behavioral structures which simply serve different functions by referring to correspondingly different sectors of the environment. In such a case the epistemological dichotomy regularly associated with the notions of “innate” (= “pre-given phylogenetical knowledge”) and “learned” (= “cognitive increase during ontogeny”) would suffer incisive questioning.     

A microscopic investigation of the lymphoid organs of the beluga,Delphinapterus leucas

Lymphoid organs from belugas, Delphinapterus leucas, ranging in age from less than one to 16 years, were harvested during a sanctioned hunt to investigate morphology. The spleen is divisible into red and white pulp and a stroma consisting of a reticular network, a collagenous capsule, and trabeculae containing smooth muscle bundles. White pulp areas appear to be devoid of follicles and consist mainly of periarteriolar lymphatic sheaths (PALS), that are larger in younger than in older belugas. Definitive marginal zones between red and white pulp are difficult to discern in older belugas. Lymph nodes are similar to those of other mammals; they possess a follicular cortex surrounding a vascular medulla composed of lymphatic cords and sinuses. Smooth muscle is abundant in the medullary region, usually in close proximity to sinuses. The expansive nodular mass at the root of the mesentery, often referred to as the “pseudopancreas,” is similar to lymph nodes in microscopic architecture. Pharyngeal tonsils and gut-associated lymphoid tissue (GALT) are found along the digestive tract and display an “active” morphology. Tonsils are comprised of lobules of follicles separated by vascular connective tissue. Epithelial-lined crypts communicate with the pharyngeal lumen. GALT consists of diffuse and follicular lymphocytes within the intestinal mucosa and submucosa. The thymus is well developed in the younger belugas, with lobules divisible into densely packed cortical zones of thymocytes and more loosely arranged medullary lymphocytes. Hassall's corpuscles are occasionally visible within the medulla. Cetaceans diverged evolutionarily from other mammals over 55 million years ago. This study investigates changes in lymphoid organ morphology in a species that now inhabits a unique ecological niche. This study also lays the groundwork for functional investigation of the beluga immune system, particularly as it relates to differences between healthy and stranded animals. © 1993 Wiley-Liss, Inc.     

An “orientation sphere” visualization for examining animal head movements

1. Animal behavior is elicited, in part, in response to external conditions, but understanding how animals perceive the environment and make the decisions that bring about these behavioral responses is challenging.
2. Animal heads often move during specific behaviors and, additionally, typically have sensory systems (notably vision, smell, and hearing) sampling in defined arcs (normally to the front of their heads). As such, head‐mounted electronic sensors consisting of accelerometers and magnetometers, which can be used to determine the movement and directionality of animal heads (where head “movement” is defined here as changes in heading [azimuth] and/or pitch [elevation angle]), can potentially provide information both on behaviors in general and also clarify which parts of the environment the animals might be prioritizing (“environmental framing”).
3. We propose a new approach to visualize the data of such head‐mounted tags that combines the instantaneous outputs of head heading and pitch in a single intuitive spherical plot. This sphere has magnetic heading denoted by “longitude” position and head pitch by “latitude” on this “orientation sphere” (O‐sphere).
4. We construct the O‐sphere for the head rotations of a number of vertebrates with contrasting body shape and ecology (oryx, sheep, tortoises, and turtles), illustrating various behaviors, including foraging, walking, and environmental scanning. We also propose correcting head orientations for body orientations to highlight specific heading‐independent head rotation, and propose the derivation of O‐sphere‐metrics, such as angular speed across the sphere. This should help identify the functions of various head behaviors.
5. Visualizations of the O‐sphere provide an intuitive representation of animal behavior manifest via head orientation and rotation. This has ramifications for quantifying and understanding behaviors ranging from navigation through vigilance to feeding and, when used in tandem with body movement, should provide an important link between perception of the environment and response to it in free‐ranging animals.

     

Dietary Restraint and Control Over “Wanting” Following Consumption of “Forbidden” Food

Eating behavior can be influenced by the rewarding value of food, i.e., “liking” and “wanting.” The objective of this study was to assess in normal‐weight dietary restrained (NR) vs. unrestrained (NU) eaters how rewarding value of food is affected by satiety, and by eating a nonhealthy perceived, dessert‐specific food vs. a healthy perceived, neutral food (chocolate mousse vs. cottage cheese). Subjects (24NR age = 25.0 ± 8.2 years, BMI = 22.3 ± 2.1 kg/m²; 26NU age = 24.8 ± 8.0 years, BMI = 22.1 ± 1.7 kg/m²) came to the university twice, fasted (randomized crossover design). Per test‐session “liking” and “wanting” for 72 items divided in six categories (bread, filling, drinks, dessert, sweets, stationery (placebo)) was measured, before and after consumption of chocolate mousse/cottage cheese, matched for energy content (5.6 kJ/g) and individual daily energy requirements (10%). Chocolate mousse was liked more than cottage cheese (P < 0.05). After consumption of chocolate mousse or cottage cheese, appetite and “liking” vs. placebo were decreased in NR and NU (P < 0.03), whereas “wanting” was only decreased in NR vs. NU (P ≤ 0.01). In NR vs. NU “wanting” was specifically decreased after chocolate mousse vs. cottage cheese; this decrease concerned especially “wanting” for bread and filling (P < 0.05). To conclude, despite similar decreases in appetite and “liking” after a meal in NR and NU, NR decrease “wanting” in contrast to NU. NR decrease “wanting” specifically for a nonhealthy perceived, “delicious,” dessert‐specific food vs. a nutritional identical, yet healthy perceived, slightly less “delicious,” “neutral” food. A healthy perceived food may thus impose greater risk for control of energy intake in NR.     

Murine “housekeeping” enzyme (genetic locus:Idh-1) is regulated in an allele-specific manner

The murine “housekeeping” enzyme, cytosolic NADP-isocitrate dehydrogenase (E.C. 1.1.1.42) (genetic locus:Idh-1), exhibited a complex pattern of allele-specific expression. Protein electrophoresis on cellulose-acetate gels and determination of relative enzymatic activity by means of densitometry revealed that in heart tissue (but not liver tissue) of certain hybrid crosses the AA-homodimer was underrepresented relative to total enzymatic activity, and the degree of underrepresentation changed during development. In mixtures of homozygous tissue extracts of heart tissue (but not liver tissue) the AA-homodimer was underrepresented relative to the BB-homodimer. Relative activity of allelic isozymes varied as a function of tissue (heart versus liver), age, and the parental source of the Idh-1^a allele, but did not vary as a function of sex. Allele-specific expression was also exhibited in kidney tissue of the same animals. In adult male kidney tissue extracts from heterozygotes, the AA-hornodimer was underrepresented relative to total enzymatic activity; in adult female kidney tissue extracts from heterozygotes, a more codominant phenotype was observed. Tissue extracts from immature hybrid animals exhibited a phenotype midway between the adult male and adult female phenotypes. Tissue extracts from castrated males exhibited a phenotype equivalent to that seen in females. Relative activity of allelic isozymes in kidney varied as a function of age and sex, but did not vary as a function of the parental source of the Idh-1^a allele. While cytosolic NADP-IDH is a “housekeeping” enzyme, expressed in multiple tissues of the mouse, differences in the relative intensities of allelic isozyme bands provide evidence for tissue- and stage-specific regulatory variation.     

Petite bodies of the “robust” australopithecines

The “robust” australopithecines are often depicted as having large and powerfully built bodies to match their massive masticatory apparatus, but until 1988 the sample of postcranial remains attributed with certainty to this group was very limited. Almost nothing was known about the body of the East African “robust” australopithecine because taxonomic attribution of the postcrania was so uncertain. The body of the South African “robust” australopithecine had to be reconstructed from about a dozen isolated fragments of postcrania. Now a partial skeleton is attributed with confidence to the East African “robust” group along with several isolated bones. The South African sample has more than tripled. Analyses of this vastly expanded sample reveal that a large portion of postcrania attributed to “robust” australopithecines from Swartkrans Member 1 (35%) are from extraordinarily small-bodied individuals similar in size to a modern Pygmy weighing as little as 28 kg. These small elements include parts from the forelimb, spine, and hindlimb. About 22% of these Swartkrans 1 “robust” australopithecines are about the same size as a modern human weighing about 43 kgs and about 43% are larger than this standard but less than or equal to a 54 kg modern human. Approximately the same pattern is true for the Swartkrans 2 hominids, but taxonomic attribution is less certain. All of the Member 3 specimens are similar in size to the 45 kg standard. The partial skeleton of the East African “robust” australopithecine (KNM-ER 1500) has hindlimb joints that would correspond to a modern human of 34 kgs although the actual weight may be 5 to 10 kgs greater judging from shaft robusticity and forelimb size. The largest postcranial element attributed with some certainty to the East African “robust” australopithecine group (the talus, KNM-ER 1464) is about the same overall size as a modern human of 54 kgs, although its tibial facet is slightly smaller. Although many previous studies have hinted at the possibility that “robust” australopithecines had relatively small bodies, the new fossils provide substantial evidence that these creatures ranged from quite small to only moderate in body size relative to modern humans. These were the petite-bodied vegetarian cousins of our ancestors. Sexual dimorphism in body size appears to be greater than that in modern humans, similar to that in Pan, and less than that in Gorilla or Pongo, although such comparisons are of limited value given the small samples, poorly known body proportions, time averaging, and many other problems.     

Genesis and structure of the so-called “balbiani body” or “yolk nucleus” in the oocyte of dugesia dorotocephala (turbellaria,tricladida)

Oogenesis of the fresh-water triclad Dugesia dorotocephala has been studied by electron microscopical methods, with particular regard to the genesis and composition of the so-called “Balbiani body.” Its origin is clearly recognizable in young oocytes where the few mitochondria present seem to gather at the level of the perinuclear ooplasm. Here they surround dense masses of finely granular, fibrillar material probably coming from the nucleus. During the previtelloge ic period, mitochondria rapidly increase in number while the dense masses progressively dissolve. In the vitellogenic oocytes the Balbiani body shows its final configuration: it appears as a large area (up to 15-20 pm in diameter) consisting of innumerable densely packed mitochondria, some smooth vesicles and free ribosomes. This aggregate of cytoplasmic organelles remains unmodified in the mature oocytes. The function of the “Balbiani body” of D. dorotocephala is as yet unclear; it can only be asserted that it is not correlated with yolk production in which the endoplasmic reticulum and the Golgi complex are involved.     

Evidence of a true pharyngeal tonsil in birds: a novel lymphoid organ in Dromaius novaehollandiae and Struthio camelus (Palaeognathae)

ABSTRACT: BACKGROUND: Tonsils are secondary lymphoid organs located in the naso- and oropharynx of most mammalian species. Most tonsils are characterised by crypts surrounded by dense lymphoid tissue. However, tonsils without crypts have also been recognised. Gut-associated lymphoid tissue (GALT), although not well-organised and lacking tonsillar crypts, is abundant in the avian oropharynx and has been referred to as the "pharyngeal tonsil". In this context the pharyngeal folds present in the oropharynx of ratites have erroneously been named the pharyngeal tonsils. This study distinguishes between the different types and arrangements of lymphoid tissue in the pharyngeal region of D. novaehollandiae and S. camelus and demonstrates that both species possess a true pharyngeal tonsil which fits the classical definition of tonsils in mammals. RESULTS: The pharyngeal tonsil (Tonsilla pharyngea) of D. novaehollandiae was located on the dorsal free surface of the pharyngeal folds and covered by a small caudo-lateral extension of the folds whereas in S. camelus the tonsil was similarly located on the dorsal surface of the pharyngeal folds but was positioned retropharyngeally and encapsulated by loose connective tissue. The pharyngeal tonsil in both species was composed of lymph nodules, inter-nodular lymphoid tissue, mucus glands, crypts and intervening connective tissue septa. In S. camelus a shallow tonsillar sinus was present. Aggregated lymph nodules and inter-nodular lymphoid tissue was associated with the mucus glands on the ventral surface of the pharyngeal folds in both species and represented the Lymphonoduli pharyngeales. Similar lymphoid tissue, but more densely packed and situated directly below the epithelium, was present on the dorsal, free surface of the pharyngeal folds and represented a small, non-follicular tonsil. CONCLUSIONS: The follicular pharyngeal tonsils in D. novaehollandiae and S. camelus are distinct from the pharyngeal folds in these species and perfectly fit the classical mammalian definition of pharyngeal tonsils. The presence of a true pharyngeal tonsil differentiates these two ratite species from other known avian species where similar structures have not been described. The pharyngeal tonsils in these ratites may pose a suitable and easily accessible site for immune response surveillance as indicated by swelling and inflammation of the tonsillar tissue and pharyngeal folds. This would be facilitated by the fact that the heads of these commercially slaughtered ratites are discarded, thus sampling at these sites would not result in financial losses.     

Amoebophrya spp. from the Bloom‐forming Dinoflagellate Cochlodinium polykrikoides: Parasites not Nested in the “Amoebophrya ceratii Complex”

Members of Amoebophrya ceratii complex are known to infect a number of free‐living dinoflagellates including harmful algal bloom species. In August and October 2012, Amoebophrya infections during two bloom events of the dinoflagellate Cochlodinium polykrikoides were observed along southern coastal waters of Korea. Microscopic observations and molecular data revealed that two different Amoebophrya parasites infected the same host species. In addition, while one developed in the host's nucleus, the other in the host's cytoplasm. Phylogenetic analyses showed that the two parasites were not nested in the previously recognized “Amoebophrya ceratii complex clade”, which contained sequences of parasites infecting numerous dinoflagellate species. Instead, they branched as sister taxa to the isolate (possibly Amoebophrya) from radiolarians Hexacontium gigantheum. Our result indicates that the two Amoebophrya parasites infecting C. polykrikoides may be different species from those inside the “complex.”     

Formation and function of the “Xestoleberis‐spot” in Xestoleberis hanaii (Crustacea: Ostracoda)

The crescent sculpture of the so‐called “Xestoleberis‐spot” develops inside the calcified valve of the family Xestoleberididae. Electron microscopic observations on both, intermoult and postmoult stages of Xestoleberis species reveal that the “Xestoleberis‐spot” system consists of three elements; two calcified chambers, a vesicle of electron‐dense material and an uncalcified procuticle. The formation and function of the “Xestoleberis‐spot” system are discussed. In conclusion, the “Xestoleberis‐spot” system functions as the muscle attachment site for several antennal muscles, and provides the material for chitinous fibers in the exocuticle of outer lamella. The unique cuticular structures of the family Xestoleberididae are due to the “Xestoleberis‐spot” system.     

Defecation by the ctenophore Mnemiopsis leidyi occurs with an ultradian rhythm through a single transient anal pore

Defecation in the ctenophore Mnemiopsis leidyi is a stereotyped sequence of effector responses that occur with a regular ultradian rhythm. Here I used video microscopy to describe new features and correct previous reports of the gastrovascular system during and between defecations. Contrary to the scientific literature, individuals defecated through only one of the two anal canals which possesses the only anal pore. The anal pore was not visible as a permanent structure as depicted in textbooks, but appeared at defecation and disappeared afterward. Time intervals between repeated defecations in individual animals depended on body size, ranging from ~10 min in small larvae to ~1 hr in large adults. Differential interference contrast microscopy revealed that both the opening and closing of the anal pore resembled a reversible ring of tissue fusion between apposed endodermal and ectodermal layers at the aboral end. Individuals of M. leidyi thus appear to have an intermittent anus and therefore an intermittent through‐gut that reoccur at regular intervals. The temporality of a visible anal pore in M. leidyi is novel, and may shed light on the evolution of a permanent anus and through‐gut in animals. In addition, mirror image dimorphism of the diagonal anal complex occurs in larval ctenophores but not in adults, indicating developmental flexibility in diagonal symmetry of the anal complex.     

Impacts of “supermoon” events on the physiology of a wild bird

The position of the Moon in relation to the Earth and the Sun gives rise to several predictable cycles, and natural changes in nighttime light intensity are known to cause alterations to physiological processes and behaviors in many animals. The limited research undertaken to date on the physiological responses of animals to the lunar illumination has exclusively focused on the synodic lunar cycle (full moon to full moon, or moon phase) but the moon's orbit—its distance from the Earth—may also be relevant. Every month, the moon moves from apogee, its most distant point from Earth—and then to perigee, its closest point to Earth. Here, we studied wild barnacle geese (Branta leucopsis) to investigate the influence of multiple interacting lunar cycles on the physiology of diurnally active animals. Our study, which uses biologging technology to continually monitor body temperature and heart rate for an entire annual cycle, asks whether there is evidence for a physiological response to natural cycles in lunar brightness in wild birds, particularly “supermoon” phenomena, where perigee coincides with a full moon. There was a three‐way interaction between lunar phase, lunar distance, and cloud cover as predictors of nighttime mean body temperature, such that body temperature was highest on clear nights when the full moon coincided with perigee moon. Our study is the first to report the physiological responses of wild birds to “supermoon” events; the wild geese responded to the combination of two independent lunar cycles, by significantly increasing their body temperature at night. That wild birds respond to natural fluctuations in nighttime ambient light levels support the documented responses of many species to anthropogenic sources of artificial light, that birds seem unable to override. As most biological systems are arguably organized foremost by light, this suggests that any interactions between lunar cycles and local weather conditions could have significant impacts on the energy budgets of birds.     

Ultrastructure of the type “B” cells in the rectal pad epithelium of Locusta migratoria

The electron microscopical structure of the type “B” cells in the rectal pad epithelium of Locusta is described. The type “B” cells occur singly in the distal region of the rectal pad epithelium. They are characteristically goblet shaped and join with contiguous type “A” or rectal pad cells, near the apical surface by means of a restricted region of septate desmosomes. Type “B” cells possess a microvillate apical membrane, with the villi arranged as a rosette overlying the apical inaginations of adjacent type “A” cells. Large numbers of microtubules and vacuoles of various sizes containing an assortment of inclusions are present in the apical region of the type “B” cells. Many of the microtubules insert distally on hemidesmosomes located in the apical plasma membrane. Rough endoplasmic reticulum and mitochondria are also present but neither are abundant. The possible significance of these findings is discussed.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

Biophysical Examinations of the Bending Stability of Various Stele Types and the Upright Axes of Early “Vascular” Land Plants

Biophysical methods allow quantitative deductions as to the “bending effectivity” of various stele types and the contribution of different tissues to the stability of upright plant axes. Considering the first occurrence of the different stele types in geological history, a strong tendency towards a higher “bending effectivity” can be observed. It can be shown that Rhynia gwynne-vaughanii, Aglaophyton major (Rhynia major) and Asteroxylon mackiei as well as probably the vast majority of early “vascular” land plants were turgor systems, i.e. that the parenchyma (when fully turgescent) is by far the most important contributory factor towards the bending stability of the upright axes.     

“Reverse” sexual dichromatism in a Neotropical frog

Sexual dichromatism is widespread among animals, but examples of “reverse” sexual dichromatism, in which females are more brightly colored than males, are extremely rare. We discovered a unique case of reverse sexual dichromatism in the golden rocket frog (Anomaloglossus beebei), a diurnal Neotropical frog. Females are bright “golden” in color, and males are drab tan with brown pigmentation that darkens when they are calling. Here, we document this color variation with calibrated digital photography and further show that there is no evidence for sex‐specific habitat matching; both sexes live in the same well‐lit habitat on green bromeliad leaves. Our results suggest that color variation in this species is an intraspecific signal and provide an important exception to the general expectation that males are more visually conspicuous in species with conventional sex roles.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats.

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent. faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium-like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum, shared characteristics with Ent. columbae. The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol. Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

What are genes “for” or where are traits “from”? What is the question?

For at least a century it has been known that multiple factors play a role in the development of complex traits, and yet the notion that there are genes “for” such traits, which traces back to Mendel, is still widespread. In this paper, we illustrate how the Mendelian model has tacitly encouraged the idea that we can explain complexity by reducing it to enumerable genes. By this approach many genes associated with simple as well as complex traits have been identified. But the genetic architecture of biological traits, or how they are made, remains largely unknown. In essence, this reflects the tension between reductionism as the current “modus operandi” of science, and the emerging knowledge of the nature of complex traits. Recent interest in systems biology as a unifying approach indicates a reawakened acceptance of the complexity of complex traits, though the temptation is to replace “gene for” thinking by comparably reductionistic “network for” concepts. Both approaches implicitly mix concepts of variants and invariants in genetics. Even the basic question is unclear: what does one need to know to “understand” the genetic basis of complex traits? New operational ideas about how to deal with biological complexity are needed.