Allocation of pyloric caecum reserves in FED and starved sea stars, Pisaster giganteus (Stimpson): somatic maintenance comes before reproduction

Pyloric caeca were removed through the raytips of sea stars, Pisaster giganteus (Stimpson), beginning their seasonal period of gonad growth. Four months later their feeding rate, gonad growth, and gametogenic activity were lower than those of intact animals, while body growth rate remained the same. Removal of only the raytips also depressed feeding rate and gonad growth. When sea stars were starved, gonad growth and gametogenic activity were lower in animals without pyloric caeca, but body weight loss was the same as in intact animals. We conclude that when food is abundant, materials are utilized to enhance somatic and gonad growth. With decreasing reserves, due either to reduced food intake and/or pyloric caecum removal, somatic maintenance and growth have priority over gonad growth in material and energy allocation. Such a pattern of resource allocation is appropriate for long-lived iteroparous animals, such as these sea stars.     

Calcitonin-like immunochemical staining in the alimentary tract of Ciona intestinalis L.

Summary Calcitonin-like immunoreactivity has been found with the peroxidase-anti-peroxidase (PAP) method in cells of the epithelium of the alimentary tract as well as in nerve cells and nerve fibers in the connective tissue underlying the epithelium of the alimentary tract of Ciona intestinalis L. The nature of these cells is discussed with reference to endocrine-like cells found in the alimentary tract of other protochordates and to the possible dual role of calcitonin occurring in the gastroenteropancreatic system, on the one hand, and in the nervous system, on the other.     

The common peptides and the cytochemistry of their cells of origin

Thirtyfive biologically active peptides are products of the 40 cells of the APUD series, which constitute the Diffuse Neuroendocrine System (DNES). Twentyone of these peptides are found not only in the cells and processes of the DNES but also in the cells and the processes of the nervous system. Hence the appellation common. To the seven original common cytochemical features of the APUD cells it is possible to add the positive results of 3 subsidiary staining techniques (Lead haematoxylin, Argyrophilia, Formaldehyde-Fluorescamine), a singly cytochemical method (Formaldehyde-ozone), and an immunocytochemical molecular marker method (neuron-specific enolase; NSE). Application of this last method demonstrates NSE in the APUD cells and confirms their origin from "neuroendocrine-programmed epiblast."     

Immunofluorescent localization of calcitonin in the ultimobranchial gland of Rana temporaria and Rana pipiens

Summary Calcitonin-like immunoreactivity has been demonstrated by immunofluorescence in the cells of the ultimobranchial gland of two species of Rana, using an indirect (sandwich) technique with anti-pure porcine calcitonin serum. The possibility of cross-reactivity, between the amphibian hormone and anti-porcine calcitonin antibody, had been anticipated on account of the observation that injected porcine calcitonin lowered the plasma calcium levels in one of the species under investigation.     

The Cytochemical Localization of Oxidative Enzymes : II. Pyridine Nucleotide-Linked Dehydrogenases

Methods are presented for the intramitochondrial localization of various diphosphopyridine nucleotide and triphosphopyridine nucleotide-linked dehydrogenases in tissue sections. The cytochemical reactions studied involve the oxidation of the substrates by a specific pyridino-protein. The electron transfer of tetrazolium salt is mediated by the diaphorase system associated with the dehydrogenase. The final electron acceptor was either p-nitrophenyl substituted ditetrazole (nitro-BT) or N-thiazol-2-yl monotetrazole (MTT), the latter giving rise to metal formazan in the presence of cobaltous ions. Mitochondrial localization of the formazan precipitate could be achieved by using hypertonic incubating media containing high concentrations of substrate and co-enzyme. A fast reduction of tetrazolium salt was obtained by chemically blocking the respiratory chain enzymes beyond the flavoproteins. Although diaphorase systems are implicated in the reduction of tetrazolium salts, specific dehydrogenases are solely responsible for the distinct distribution pattern obtained in tissues with various substrates. The present findings in tissue sections are discussed in conjunction with existing biochemical evidence from differential centrifugation experiments.     

Akute Vitamin A-Intoxikation der Maus

Summary Isolated fixed liver nuclei of Rana pipiens were stained at varied pH by the acid dye, fast green FCF. The amount of nuclear protein, as determined by cytophotometric measurement of the relative absorption of the stained nuclei, was found to increase in proportion to nuclear size when the pH of the dye solution was below 4.0. Relative absorption was found to be independent of nuclear size, but proportional to the pH of the staining solutions in the pH range between 5.0 and 7.0, These data suggest a change in composition and/or structure of the nuclear protein with increasing nuclear size.This investigation was supported by a grant from the U.S. Public Health Service, GM-10003-04.Post-Doctoral Trainee under U.S. Public Health Training Grant to the Department of Pathology, University of Florida, NIH-GM-1142-03.Supported by a Career Development Award from the National Institute of Child Health and Human Development, K3-HD-6176-04.     

Sticky plant traps insects to enhance indirect defence

Plant‐provided foods for predatory arthropods such as extrafloral nectar and protein bodies provide indirect plant defence by attracting natural enemies of herbivores, enhancing top‐down control. Recently, ecologists have also recognised the importance of carrion as a food source for predators. Sticky plants are widespread and often entrap and kill small insects, which we hypothesised would increase predator densities and potentially affect indirect defence. We manipulated the abundance of this entrapped insect carrion on tarweed (Asteraceae: Madia elegans) plants under natural field conditions, and found that carrion augmentation increased the abundance of a suite of predators, decreased herbivory and increased plant fitness. We suggest that entrapped insect carrion may function broadly as a plant‐provided food for predators on sticky plants.     

Leaf drop affects herbivory in oaks

Leaf phenology is important to herbivores, but the timing and extent of leaf drop has not played an important role in our understanding of herbivore interactions with deciduous plants. Using phylogenetic general least squares regression, we compared the phenology of leaves of 55 oak species in a common garden with the abundance of leaf miners on those trees. Mine abundance was highest on trees with an intermediate leaf retention index, i.e. trees that lost most, but not all, of their leaves for 2–3 months. The leaves of more evergreen species were more heavily sclerotized, and sclerotized leaves accumulated fewer mines in the summer. Leaves of more deciduous species also accumulated fewer mines in the summer, and this was consistent with the idea that trees reduce overwintering herbivores by shedding leaves. Trees with a later leaf set and slower leaf maturation accumulated fewer herbivores. We propose that both leaf drop and early leaf phenology strongly affect herbivore abundance and select for differences in plant defense. Leaf drop may allow trees to dispose of their herbivores so that the herbivores must recolonize in spring, but trees with the longest leaf retention also have the greatest direct defenses against herbivores.     

Building up biogeography: Pattern to process

Linking pattern to process across spatial and temporal scales has been a key goal of the field of biogeography. In January 2017, the 8th biennial conference of the International Biogeography Society sponsored a symposium on Building up biogeography—process to pattern that aimed to review progress towards this goal. Here we present a summary of the symposium, in which we identified promising areas of current research and suggested future research directions. We focus on (1) emerging types of data such as behavioural observations and ancient DNA, (2) how to better incorporate historical data (such as fossils) to move beyond what we term “footprint measures” of past dynamics and (3) the role that novel modelling approaches (e.g. maximum entropy theory of ecology and approximate Bayesian computation) and conceptual frameworks can play in the unification of disciplines. We suggest that the gaps separating pattern and process are shrinking, and that we can better bridge these aspects by considering the dimensions of space and time simultaneously.     

Stock information requirements for quota management systems in commercial fisheries

Economic inefficiency and other problems associated with managing fisheries through restrictions on fishing times, places and gear have led to development of management systems based on individual fishers' quotas. But this shift from input controls to output controls calls for much more accurate and timely stock assessments. The risk of stock collapse resulting from overfishing, coupled with growing pressure for low-risk resource management policies, call for conservative quota-setting in the face of uncertain stock information. Under existing assessment systems, quotas may need to be so conservative that foregone catches could wipe out the economic gains from quota management. This problem might be overcome by taking advantage of the incentives of quota-holders to contribute to, and invest in, the gathering of information to improve stock assessments.