bluuebunny/crossref_metadata_2025_split huggingface dataset:
The recovery from anaerobic metabolism in invertebrates
Authors: Ellington W. Ross 
Published: June 2005

AbstractThe duration and completeness of recovery from anaerobic metabolism is of important functional consequence in invertebrates. Two basic processes occur during recovery: (1) recharging of the phosphagen and ATP pools and (2) disposal of end products by excretion, oxidation, or conversion back to anaerobic substrates. The recovery process in invertebrates is largely aerobic, as is evidenced by the near universality of the oxygen debt phenomenon. However, there is often a lack of correlation between end product accumulation and the magnitude of the oxygen debt. Typically, ATP and phosphagen levels are recharged very rapidly during recovery–ATP (0.25 to 1.0 hr) and phosphagens (0.5 to 4 hr). Excretion of propionate, acetate, and, occasionally succinate, is relatively common in annelids and has also been observed in a number of bivalve molluscs. Nitrogen‐containing end products do not appear to be excreted. Cephalopods and large arthropods show elevated hemolymph end product levels following anoxia/hypoxia. In arthropods, these end products display a protracted return to control levels during recovery. In cephalopods, some octopine may be rapidly taken up and metabolized by the heart, brain, and gill. The sites of lactate metabolism in arthropods are unclear. In contrast to the situation in cephalopods and arthropods, most end products in the adductor muscles of bivalve molluscs do not appear to be exported, but are metabolized within the tissue itself. End ducts such as octopine, succinate, and alanine thus appear to be metabolized at the site of their production. Octopine and lactate appear to be gluconeogenic substrates in cephalopods and arthropods, respectively. Although many of the enzymes involved in gluconeogenesis are present in bivalve molluscs, this process has not been demonstrated in this group. Recovery from anaerobic metabolism remains a fruitful area for future research. Of special interest is the identification of sites of gluconeogenesis in the larger, more active species.
Growth and reproduction of two species of Akodon and their hybrids
Authors: Merani María Susana , Vercellini O. , Acuña Ana maría , Horgan C. , Roldan E. R. S. 
Published: June 2005

AbstractGrowth and reproduction of Akodon molinae (A.m.), A. dolores (A.d.) (Rodentia: Cricetidae), and their hybrids are described. A.d. showed less fertility under animal room conditions, fewer “successful” matings, similar litter sizes, and an altered sex proportion as compared to A.m.; A.d. ovulatory index is supposed to be higher than mean litter size. X‐linked lethal gene(s) and chromosome polymorphisms are possible causes of these variations. Interspecific crosses showed a marked seasonal (summer) tendency in parturitions. Intraspecific matings also produced young during winter. F1 hybrids showed a reversed tendency, while F2 matings returned to the parental pattern. A.d. ♀ × A.m. ♂ and F1 crosses presented larger litter sizes than the other pairings.A.m. exhibited sexual differences in weight after 60 days of age. A.d. and F1 hybrids did not show significant differences in weight of both sexes at any age. A.m. males and females were heavier than A.d. individuals except 12 months after birth. F1 hybrids born to A.m. ♀ were heavier at birth than the A.d. ♀ s interspecific offspring, and may be interpreted as a maternal influence of the A.m. females. Hybrids were heavier than their parents at birth and some of them were also heavier at 21 days, and probably is due to pseudoheterosis. The comparison of body measurements between sexes of both species did not give conclusive results. A.m. females were larger than females of A.d. Males of both species showed similar total lengths; A.m. males had larger body lengths and shorter tails. Body measurements were not related to weight variations. However, differences in weight and measurements between sexes appeared simultaneously at 2–6 months. This probably reflected the attainment of maturity.
Genetic similarity between species of Akodon (Rodentia, Cricetidae)
Authors: Apfelbaum Liliana I. , Blanco Antonio 
Published: June 2005

AbstractGenetic similarity between species of rodents of the Akodon genus (A. dolores, A. molinae, and A. azarae) has been estimated by analysis of electrophoretic zymograms corresponding to 23 loci. Nei's coefficient between A. dolores and A. molinae was within the range usually found in conspecific populations. This evidence plus the successful production of “hybrids” (Merani et al., J. Exp. Zool., 206:343–346, '78) suggests that A. dolores and A. molinae may represent geographic races of the same species.
Negative correlation of age and the levels of pineal melatonin, pineal N‐acetylserotonin, and serum melatonin in male rats
Authors: Pang S. F. , Tang F. , Tang P. L. 
Published: June 2005

AbstractPineal concentrations of N‐acetylserotonin and melatonin and serum levels of melatonin were studied in 3‐wk‐old (prepubertal), 8‐wk‐old (adult), and 17‐mo‐old (senile) male rats. They were adapted to a photoperiod of 12 h light/12 h darkness for a minimum of 1 wk and killed at mild‐light and mid‐dark. Melatonin and N‐acetylserotonin were determined by radioimmunoassay. The concentrations of pineal N‐acetylserotonin and melatonin were high in the dark period and low in the light period. Statistical analysis indicated that pineal N‐acetylserotonin and melatonin levels per 100 gm body weight declined with age. Similarly, serum melatonin demonstrated diurnal changes in all the age groups studied. In addition, there was a significant reduction in the levels of serum melatonin with age. The parallel patterns of decrease in pineal and serum melatonin levels with age suggest a decline in pineal secretion of melatonin in the older animals.
Preparation and some respiratory properties of coupled mitochondria from ribbed mussel (Modiolus demissus) gill tissue
Authors: Burcham James M. , Ritchie Al , Bishop Stephen H. 
Published: June 2005

AbstractPreliminary experiments with 2,4‐dinitrophenol (DNP), 2,4,6‐trinitrophenol (TNP), and sodium azide (NaN3) indicated that most of the oxygen consumption by ribbed mussel gill tissue is the result of mitochondrial respiration. A procedure utilizing isoosmotic sucrose, EGTA, defatted serum albumin, and HEPES as the isolation medium was devised for the preparation of fully coupled ribbed mussel gill mitochondria. Optimal rates of respiration and respiratory coupling required substrate, ADP, inorganic phosphate, and a fairly high KCl concentration (90 mM) in the assay medium. Glutamate, proline, malate, and succinate stimulated oxygen consumption with high respiratory control indices and P/O of 3, 3, 3 and 2, respectively. Pyruvate was a weak stimulator of mitochondrial respiration and showed a low respiratory control index with a low P/O. Preparation of gill mitochondria in isoosmotic solutions containing high KCl concentrations (150 mM) yielded mitochondria showing state 2 respiration, slow partially uncoupled ATP synthesis during state 3 respiration and no state 4 respiration. D‐mannitol was not used in the mitochondrial isolation or assay medium because of the probable presence of a D‐mannitol oxidase in these gill mitochondria.
Autoradiographic demonstration of adrenergic innervation to scale melanophores of a teleost fish, Oryzias latipes
Authors: Yamada Koji , Miyata Seiji , Katayama Heizaburo 
Published: June 2005

AbstractThe possibility of adrenergic innervation to melanophores in scales of Oryzias latipes was investigated using 3H‐norepinephrine (3H‐NE) by light microscopic autoradiography. When isolated scales were incubated in 3H‐NE, there was observed plexus of varicose fibers labeled with 3H‐NE which intimately enclosed the stellate processes and cell bodies of melanophores. These labeled fibers could not be detected in cocaine‐treated or denervated scales. Potassium ions caused a considerable reduction in the labeling of varicose fibers, which was accompanied with aggregation of melanosomes within melanophores. These findings suggest that the labeled fibers observed are compatible with adrenergic nerve fibers that control the melanosome movements within melanophores.
Monoclonal antibodies developed against Botryllus blood cell antigens bind to cells of distinct lineages during embryonic development
Authors: Schlumpberger J. M. , Weissman I. L. , Scofield V. L. 
Published: June 2005

AbstractMonoclonal antibodies that bind to adult Botryllus blood cell surface antigens were used to detect and localize identical or cross‐reacting antigenic determinants on Botryllus embryonic cells. These anti‐Botryllus monoclonal reagents could be divided into three categories: 1) those that bound to most embryonic cell types, including all very early embryonic cells; 2) those that bound only to embryonic blood cells and a few other embryonic cell types; and 3) those that did not bind detectably to any embryonic cells.
Timing of early morphogenetic events in tetraploid starfish embryos
Authors: Mita I. , Obata C. 
Published: June 2005

AbstractWhen starfish eggs were treated with caffeine, they developed parthenogenetically as tetraploid embryos. The timing of cleavages and gastrulation was compared between these tetraploid embryos and control diploid embryos. The following results were obtained: 1) The number of synchronous cleavages was ten in controls but nine in tetraploid embryos; 2) tetraploid embryos began to gastrulate at almost the same time after first cleavage as did control embryos; 3) the average number of constituent cells of tetraploid gastrulae was about 2,300, whereas that of control gastrulae was about 4,000. These results indicate that 1) the initiation of asynchronous cleavages is closely associated with the nucleocytoplasmic ratio; and 2) the timing of gastrulation is not determined by the number of cell divisions. These conclusions are in good accord with the results of a previous study on timing of early morphogenetic events in half eggs whose cytoplasm was decreased to half that of normal eggs (Mita, '83).
Determination of the plane of bilateral symmetry in the teleost fish, Oryzias latipes
Authors: Long Wilbur L. , Speck Nancy A. 
Published: June 2005

AbstractGravitational factors appear to influence the establishment of bilateral symmetry in amphibia, birds, elasmobranchs, chondrostean fishes, and teleostean fishes. Correlations between the plane of symmetry and the planes of the first or second cleavage have similarly been noted. Evidence is presented indicating that neither the direction of gravity nor the first or second cleavage planes can be correlated with the orientation of bilateral symmetry in the Japanese ricefish, Oryzias latipes. An alternative explanation for the previous data supporting a gravitational influence in teleostean fishes is offered.
The modifications of cortical endoplasmic reticulum during in vitro maturation of Xenopus laevis oocytes and its involvement in cortical granule exocytosis
Authors: Campanella C. , Andreuccetti P. , Taddei C. , Talevi R. 
Published: June 2005

AbstractIn Xenopus laevis eggs, cisternae shells which surround cortical granules (CG) are part of a cortical endoplasmic reticulum (ER) network. In this paper the origin of such ER shells has been studied in full‐grown, progesterone‐exposed Xenopus oocytes. Furthermore, the possible role of the cortical ER in the activation process has been investigated by pricking maturing oocytes. It has been shown that in full‐grown ovarian oocytes ER CG shells are absent and ER cisternae are extensively and randomly distributed throughout the peripheral cytoplasm, where they appear to be continuous with annulate lamellae (AL). Following hormone treatment, the AL completely disaggregate and the ER cisternae gradually migrate to the cortex where they surround the CG constituting the typical cortical network described in uterine eggs. Furthermore, it has been found that 8 h after progesterone treatment (before the first polar body extrusion) the response to pricking (CG exocytosis) occurs only at the animal half; there is no observable response in the vegetal half. At this time ER shells surround CG only in the animal hemisphere. A complete CG exocytosis occurs following the first polar body emission, when the cortical ER is well organized in the whole oocyte cortex. The correlation between the differentiation of the cortical ER and the arousal in the oocyte of the ability to respond to a pricking stimulus is discussed in the light of an involvement of the cortical ER in the propagation of CG exocytosis.
Calcium ultrastructural localization in Xenopus laevis eggs following activation by pricking or by calcium ionophore A 23187
Authors: Andreuccetti P. , Denis‐Donini S. , Burrini A. G. , Campanella C. 
Published: June 2005

AbstractIn the egg of Xenopus laevis a cortical network of smooth endoplasmic reticulum (SER) surrounds and interconnects each cortical granule (CG) (Campanella and Andreuccetti, '77). This network is a possible intracellular site of calcium storage to be called into action for CG exocytosis. In our experiments, Xenopus eggs, unfertilized or activated by pricking or by calcium ionophore A 23187, have been fixed in osmium‐pyroantimonate for calcium localization.Our data show that deposits can be detected only in activated egs. The calcium chelator edetate (EGTA) and x‐ray microprobe analysis demonstrate that they contain calcium. Deposits are found on liposomes and on all intraovular cytomembranes, which therefore appear to be possible sites of calcium sequestration. In the case of ionophore‐activated eggs, deposits are detectable independently of the presence of extracellular calcium. These data show that in Xenopus at activation an intracellular liberation of calcium occurs similar to that described in other species.Furthermore, the fact that antimony deposits are observed only after activation makes Xenopus eggs appropriate material in which to follow the temporal and spatial sequence of appearance of the deposits during the early stages of activation. Our results show that antimony deposits appear first in SER vesicles between the plasma membrane and CGs and then spread to the rest of the egg cytomembranes. These data corroborate our hypothesis that in Xenopus the cortical SER network is the first intracellular site where calcium is released at activation. The possible mechanism of calcium release and propagation along the egg cortex is discussed.
Effects of hypophysectomy on some osmoregulatory parameters of the catfish, Heteropneustes fossilis (Bloch)
Authors: Parwez Iqbal , Goswami Shashi V. , Sundararaj Bangalore I. 
Published: June 2005

AbstractThe catfish, H. fossilis, survives for long periods after hypophysectomy, although with impaired osmoregulatory mechanisms. Plasma osmolarity and cortisol levels decline significantly within 2 hr after hypophysectomy and attain the lowest values by about 27 hr. Hypophysectomy also results in a marked decrease in urine flow rate principally due to reduced glomerular filtration. The reduction in the ability of the kidney of hypophysectomized catfish to eliminate water results in hyperhydration of blood and muscle. Urine osmolarity and sodium concentration increase due to reduced tubular reabsorption of sodium. There is, however, no net change in the total urinary sodium loss. The catfish survives in fresh water after hypophysectomy presumably because its tissues can tolerate significant dilution of the body fluids.
Neuroendocrine changes in male hamsters following photostimulation
Authors: Steger R. W. , Bartke A. , Matt K. S. , Soares M. J. , Talamantes Frank 
Published: June 2005

AbstractTransfer of gonadally regressed male golden hamsters from a short (5 L:19 D) to a stimulatory (14 L:10 D) photoperiod elicits, within 24 hr, significant changes in hypothalamic dopamine, serotonin, and possibly norepinephrine metabolism. Hypothalamic LHRH content was significantly elevated in short‐photoperiod animals, but within 24 hr of transfer to a 14:10 photoperiod, LHRH declined to levels not different from those in hamsters maintained continuously in a long photoperiod. Plasma FSH levels were also significantly elevated within 24 hr of transfer, but increases in plasma LH were somewhat slower. Chronic treatment with the tyrosine hydroxylase inhibitor, α‐methyl tyrosine (αMPT), which inhibits catecholamine synthesis, blocked the effect of a stimulatory photoperiod on plasma FSH levels, while treatment of 5:19 hamsters with the catecholamine precursor, L‐dopa, mimicked the effects of photostimulation on plasma FSH levels. Testicular weights were not affected by αMPT or L‐dopa treatment for 1 week. From these data, it appears that endocrine events associated with photoperiod‐induced testicular recrudescence are under the control of hypothalamic neurotransmitters.
Effects of house fly oostatic hormone on egg development neurosecretory hormone action in Aedes atropalpus
Authors: Kelly Thomas J. , Birnbaum Mark J. , Woods Charles W. , Borkovec Alexej B. 
Published: June 2005

AbstractOostatic hormone, prepared from mature female house flies, Musca domestica, was examined for its effect on processes mediated by egg development neurosecretory hormone (EDNH). When injected into newly emerged adult female mosquitoes, Aedes atropalpus, oostatic extracts inhibited vitellogenic growth of the ovaries. Comparison of oostatic activities in heads, thoraces, and abdomens of house flies showed that the major portion was present in the abdomens, apparently associated with the ovaries. In contrast to untreated vitellogenic females, no ecdysone or 20‐hydroxyecdysone could be detected in female mosquitoes injected with the oostatic extract. Vitellogenic growth and ecdysteroid levels were suppressed in decapitated females injected with a mixture of extracts containing EDNH and oostatic activities. Since the normal vitellogenic and steroidogenic responses to EDNH can be suppressed by simultaneous injection of EDNH and oostatic material, it is suggested that oostatic hormone acts at a level subsequent to EDNH release. However, we cannot rule out at this time that EDNH release, itself, is also affected.
Abdominal positioning interneurons in crayfish: Projections to and synaptic activation by higher CNS centers
Authors: Larimer James L. , Moore Darrell 
Published: June 2005

AbstractIntracellular recording, stimulation, and Lucifer dye injections were used to characterize abdominal positioning interneurons from the neuropile of the second through sixth abdominal ganglia of the crayfish, Procambarus clarkii. Motor outputs of these cells were recorded with extracellular electrodes placed on various flexion and extension roots along the nerve cord. In an effort to assess the functional relationships between the postural interneurons in the abdomen and those known to exist in the circumesophageal connectives (CECs), a stimulus pulse train was delivered to each of the CECs while monitoring the intracellular responses of the impaled interneurons. Abdominal positioning interneurons were grouped into four general categories based on their responses to CEC stimulation: 1) those that projected their axons directly through the CECs; 2) those that were remotely activated to spiking; 3) those locally activated to produce EPSPs or IPSPs; and 4) those that were not affected by CEC stimulation.The majority of abdominal positioning interneurons encountered in this study evoked flexion (N = 82), with relatively fewer evoking extension (N = 29). A major difference appeared between the two classes. Whereas 39% of the flexion interneurons had axons coursing to the brain, only 7% of the axons of extension interneurons coursed rostrally beyond the thoracic level. Finally, the large majority of those flexion and extension interneurons that lacked processes in the CEC received synaptic inputs at various levels along the lower CNS from other CEC neurons. Thus, control of abdominal positioning involves neurons at all levels in the CNS—some sequentially organized, others forming “through” pathways, but all with multiple input sites.
Demonstration of H‐2 antigens on preimplantation mouse embryos using conventional antisera and monoclonal antibody
Authors: Warner Carol M. , Spannaus Donna J. 
Published: June 2005

AbstractMouse embryos at the 2‐cell, 8‐cell, and blastocyst stages of development were examined for the presence of H‐2 antigens by immunoperoxidase labeling and transmission electron microscopy. Conventional antisera made in congenic mouse strains were used to study embryos of four different haplotypes: b, a, k, and d. Blastocysts showed uniform heavy labeling of all cells of the trophectoderm, 8‐cell embryos showed lighter labeling of only some of the cells, and 2‐cell embryos showed no labeling. Similar results were found for all four haplotypes studied. In addition, monoclonal antibody 11–4.1 (anti‐Kk) was reacted with homologous (H‐2k) and heterologous (H‐2b) blastocysts. Positive results with the monoclonal antibody corroborates the concept that H‐2 antigens are expressed on early mouse embryos.
In vitro development of the embryonic mouse inner ear following exposure to trypsin
Authors: Saver Jeffrey L. , Van De Water Thomas R. 
Published: June 2005

AbstractTrypsin has been shown to disrupt normal in vitro morphogenesis of embryonic organ rudiments. Otic tissues derived from 11‐, 12‐, and 13‐day‐old mouse embryos were exposed to either Ca++‐ and Mg++‐free PBS or 0.25% trypsin dissolved in Ca++‐ and Mg++‐free PBS prior to explantation into organ culture. Trypsin treatment of otic explants disrupted the expression of the normal pattern of inner‐ear development in vitro. There was a direct correlation between the embryonic age at time of exposure to trypsin and the severity of dysmorphogenesis of the inner ear. The younger explants showed abnormalities of both vestibular and auditory structures, whereas with increasing embryonic age, abnormalities were confined more to the auditory portion of the inner ear. The results suggest that integrity of the otocyst basal lamina and epitheliomesenchymal tissue interactions are important factors in early otic development. It is postulated that the major effect of trypsin on inner‐ear morphogenesis is through disruption of these factors, which may act to regulate the progressive expression of early otic development.
Long‐term effects of hypothalamic lesions on the pituitary and its target organs in the killifish Fundulus heteroclitus: II. Darkening
Authors: Pickford Grace E. , Knight W. Rea , Knight Janet N. , Baker Bridget I. 
Published: June 2005

AbstractPresumed lesions in the area of the nucleus preopticus (NPO) of male Fundulus heteroclitus resulted in chronic darkening in 12 fish. Sections revealed that all dark fish were severely injured in the nucleus opticus hypothalami (NOH) (Repérant et al., '82); in 11 cases there was injury to the optic tracts but in one the tracts were uninjured. Seven dark fish were tested on a white background: four were unable to assume pallor but three gradually paled. A caudal band remained dark in the four fish that did not fade but paled in the three that became slowly paler. It is concluded that the pathway to the thalamic paling center was destroyed but that low levels in melanophore‐concentrating hormone (MCH) persisted in the three fish whose denervated caudal bands faded. Darkening was not due to proliferation of new melanocytes or to the synthesis of new melanin, but solely to a chronic state of melanophore dispersion. Pituitary melanocytes appeared mainly normal, and secretion of the melanophore‐dispersing hormone was probably not excessive.