scholarly journals Notes on the Early Stages of two Polychaetes, Nephthys hombergi Lamarck and Pectinaria koreni Malmgren

Author(s):  
Douglas P. Wilson

Trochosphekes of Nephthys hombergi Lamarck are readily obtainable at Plymouth when the adult worms are mature from June to September. The worms are dug out of the muddy sand on the lower regions of the shore, and their eggs and sperms obtained by slitting open the body cavity. Fertilizations are easily made in glass finger-bowls of clean sea-water. Although apparently ripe worms have been kept under sea-water circulation in the laboratory, and under a variety of conditions, none has ever been induced to spawn naturally. After some days the body walls of some individuals have split along the back and shed their genital products in that way; these, however, were probably unhealthy and abnormal. A high percentage of the eggs got by cutting open the worms have fertilized and given rise to cultures of strongly swimming larvæ. During the summers of 1932–34 much time and effort were expended in numerous attempts to rear these larvæ, but in no single instance was success obtained. It had been hoped to collect material for a detailed histological study of the development, for it may be of a straightforward and simple type that would throw light on various problems of Polychæte embryology. Although these hopes have not been realized it seems of value to describe the trochosphere of which no entirely satisfactory account exists, in spite of a few references to it by previous writers.

2016 ◽  
Vol 113 (45) ◽  
pp. 12637-12642 ◽  
Author(s):  
Netta Vidavsky ◽  
Sefi Addadi ◽  
Andreas Schertel ◽  
David Ben-Ezra ◽  
Muki Shpigel ◽  
...  

We investigated the manner in which the sea urchin larva takes up calcium from its body cavity into the primary mesenchymal cells (PMCs) that are responsible for spicule formation. We used the membrane-impermeable fluorescent dye calcein and alexa-dextran, with or without a calcium channel inhibitor, and imaged the larvae in vivo with selective-plane illumination microscopy. Both fluorescent molecules are taken up from the body cavity into the PMCs and ectoderm cells, where the two labels are predominantly colocalized in particles, whereas the calcium-binding calcein label is mainly excluded from the endoderm and is concentrated in the spicules. The presence of vesicles and vacuoles inside the PMCs that have openings through the plasma membrane directly to the body cavity was documented using high-resolution cryo-focused ion beam-SEM serial imaging. Some of the vesicles and vacuoles are interconnected to form large networks. We suggest that these vacuolar networks are involved in direct sea water uptake. We conclude that the calcium pathway from the body cavity into cells involves nonspecific endocytosis of sea water with its calcium.


2019 ◽  
Vol 8 (2) ◽  
pp. 37-40
Author(s):  
Hikmah Supriyati ◽  
Rakhmiyati Rakhmiyati ◽  
Muhammad Ja’far Luthfi

Sharks are sea water fishes belong to the class Chondrichthyes, Subclass Elasmobranchii. Sharks are cartilaginous fish that have a different osmoregulation process than any other sea water fish. Cartilaginous fish is the only vertebrate that can maintain urea. This study aims to determine the anatomical and histological structure of the kidney in the anterior, medial and posterior parts of kidney. The study was conducted by observing anatomy of the kidney. Histological preparations were made using the paraffin method. Qualitative descriptive data analysis was done. Research results show that shark kidneys consist of three parts, namely the head kidney, the body kidney, and the tail kidney. Kidney sharks are brownish red with a size of 18 cm long. Histological observations of shark kidney in the head kidney reveals many glomerulus, body kidney reveals many distal and tubule proximal contractile tubules whereas tail kidney reveals stroma that is rarely found in vertebrate kidney.


The following description is based upon dissections and preparations made in the laboratory of the Sleeping Sickness Commission at Entebbe since my arrival here at the beginning of April. I hope on my return to England to work up my material into a detailed memoir on the anatomy and histology. Time does not suffice for me to complete my work out here, but it seemed worth while, nevertheless, to bring forward as soon as possible a brief description of the general anatomy of the fly, and especially of its digestive tract, on account of its importance for the study of the evolution of the trypanosomes of Sleeping Sickness, and other tsetse-fly diseases, within the body of their invertebrate host. In this paper I do not propose to attempt to deal with either the muscular system or the respiratory tracheal system. The former of these is so complex that much more time would be required for working it out than I could afford to spend, and it is, moreover, of little or no importance for the aim in view; while the tracheal system, or at least its finer branches, are so intimately connected with the fat-body, which here, as in other insects, fills up the body-cavity, that in the process of clearing up and laying bare the organs, the tracheæ are for the most part removed. Special muscles or tracheae will be mentioned in places, but otherwise no account will be taken of these two systems.


1997 ◽  
Vol 77 (4) ◽  
pp. 1243-1246 ◽  
Author(s):  
C.J. Cornwell ◽  
J.B. Messenger ◽  
R.T. Hanlon

The chromatophore system of the small loliginid squid Alloteuthis subulata (Mollusca: Cephalopoda) is very simple and the repertoire of body patterns limited. There are red and yellow chromatophores only. On the dorsal mantle there are more yellows than reds; on the ventral mantle and there are more reds than yellows. The dorsal reds are larger than the yellows and bear more radial muscles. The significance of these findings is discussed.Alloteuthis subulata Lamarck is a small loliginid, common in shallow water near Plymouth (Holme, 1974; Lipinski, 1985; Rodhouse et al., 1988). Little is known of its natural history and behaviour and chromatophores and body patterns of adults have never been described, although the skin of this species has been used in physiological studies of colour change (Messenger, 1991; Messenger et al., 1991; Cornwell & Messenger, 1995).Over 100 adult animals of both sexes, caught by trawl at depths of 10–60 m, were examined; their mantle lengths ranged from 70 to 130 mm. Living animals were observed in large aquaria with circulating sea-water. Counts and measurements of chromatophores were made on colour photographs (taken through a Nikon dissecting microscope) of pieces of fresh skin (20×20 mm) dissected from animals killed by decapitation or after MgCl2 anaesthesia (Messenger et al., 1985). Chromatophores were counted first when fully retracted (by 1×10−3 M 5-HT) and then when fully expanded (with 1×10−3 M L-glutamate: Cornwell & Messenger, 1995). All measurements were made in the same area of the body: the central and anterior part of the mantle, dorsally and ventrally (Figure 2).


The first attempts to produce a capacity for induction in tissue which is normally incapable of performing such an action were made by Spemann and Geinitz in 1927. They grafted a fragment of presumptive ectoderm into the organization centre of another embryo, and, removing it a few hours later, found that it had been “infected” with the inducing capacity of the tissues by which it had been surrounded. The experiment inevitably suggested that the inducing capacity is the property of a chemical substance which had diffused out of the organizer tissue into the grafted ectoderm fragment. A similar hypothesis could be used to explain the observation of Mangold and Spemann (1927) that in normal development the presumptive neural plate acquires inducing capacity at the same time and in proportion as it is underlain and determined by the mesodermal organizer. The first suggestion that the non-inducing parts of a Urodele gastrula themselves possess an organizing capacity, which is masked but only awaits activation or release, emerged in the work of Dürken (1926), Bautzmann (1929, a , b ), Kusche (1929), and Holtfreter (1931), and attention was first drawn to it by Huxley (1930). The German authors showed that if fragments of the gastrula are “interplanted” into the body cavity or optic vesicle of older larvae, they may develop into something other than their presumptive fate, and in particular, presumptive epidermis or neural plate may develop into various mesodermal derivatives such as notochord or muscle. Huxley pointed out the similarity between this phenomenon, which was called bedeutungsfremde Selbstdifferenzierung , and the results of isolating parts of the axial gradient system of lower organisms, which have been particularly described by Child (summaries 1928, 1929). An isolated part of an axial gradient system reconstructs a “dominant region”; and Huxley suggested that we could account for bedeutungsfremde Selbstdifferenzierung by supposing that an isolated part of a gastrula reconstructs the dominant region, i.e ., the organization centre. In the spring of 1932 one of us (C. H. W.), while on a visit to the laboratory of Dr. O. Mangold in Berlin for the purpose of learning the technique of amphibian operations, attempted to carry the matter a step further. If Huxley’s explanation were correct, one would have to suppose that a capacity for behaving like a “dominant region”, that is, for inducing, is latent in the presumptive ectoderm, and this capacity should become manifest when the ectoderm changes into a dominant region after isolation. The following experiment was therefore made to test this point. Fragments of presumptive ectoderm from a young gastrula were interplanted into the eye-cavity of Anuran tadpoles, from which the eye-ball had previously been removed. After two days the interplanted tissue was removed and grafted by the Einsteck method into the blastocoele of young newt gastrulae, to discover whether they were capable of inducing the formation of neural plate. Three sets of controls were made. In one set organizing tissues were interplanted for two days and then tested to see whether their inducing capacity had been impaired, in the second set organizing tissue was isolated for two days in Holtfreter solution, and then tested, and in the third set presumptive ectoderm was isolated for two days in Holtfreter solution and tested for inducing capacity.


1979 ◽  
Vol 57 (1) ◽  
pp. 237-246 ◽  
Author(s):  
J. H. Youson ◽  
J. Lee ◽  
I. C. Potter

A histological study using Sudan Black B has been made of the distribution and relative density of fat in the various regions of the body of larval (ammocoete), metamorphosing, and young adult stages of the anadromous sea lamprey, Petromyzon marinus L., caught in New Brunswick. The principal sites of fat storage are located in and around the fat column, lateral to the notochord, between the notochord and either the cardinal or caudal veins, surrounding the body cavity, beneath the skin, and in the myosepta and the nephric fold. Dense but more restricted sites are present lateral to the nerve cord, between the bundles of muscle fibres, and surrounding the pharyngeal cavity. Fat is most abundant in large ammocoetes captured in May and June and in those displaying the very earliest stages of metamorphosis in July. The amount of fat declines during metamorphosis, but is still abundant in November just prior to the time when the sea lamprey can commence parasitic feeding. Fat was undetectable, however, in nearly every site in those animals in which feeding was delayed until the following May. This study shows that sea lampreys accumulate large amounts of fat at the end of larval life by employing a wide variety of different storage sites. It also demonstrates that the fat in virtually all of these sites may be exhausted when the nontrophic period following the initiation of metamorphosis is of a very long duration.


Author(s):  
А.С. Казицкая ◽  
Т.К. Ядыкина ◽  
М.С. Бугаева ◽  
А.Г. Жукова ◽  
Н.Н. Михайлова ◽  
...  

В условиях непрерывного воздействия неблагоприятных факторов окружающей и производственной среды на человека особую актуальность приобретает изучение механизмов, поддерживающих гомеостаз организма. Длительное поступление фторидов в организм приводит к формированию хронической фтористой интоксикации, патогенез которой вызывает многочисленные споры и дискуссии. До сих пор недостаточно внимания уделяется изучению висцеральной патологии, обусловленной нарушениями иммунного статуса в условиях воздействия на организм соединений фтора. Практически отсутствуют исследования по изучению иммунной реактивности, определяющей морфофункциональный характер ответной реакции печени на ранних стадиях развития фтористой интоксикации. Цель работы - изучение действий патофизиологических механизмов иммунной реактивности печени при субхроническом действии на организм соединений фтора. Методика. Опыты проведены на 210 лабораторных крысах-самцах массой 180-220 г., разделенных на 2 группы: контрольную (n=80) и группу животных с субхроническим действием фторида натрия (n=130). Экспериментальные животные в течение 12 нед имели свободный доступ к водному раствору фторида натрия (концентрация 10 мг/л, что составляет суточную дозу фтора 1,2 мг/кг массы тела). Для изучения иммунологических и биохимических показателей забирали кровь из хвостовой вены через 1, 3, 6, 9, 12 нед от начала эксперимента. Для оценки состояния гуморального звена иммунитета определяли уровень сывороточных иммуноглобулинов (IgA, IgG, IgM) иммуноферментным анализом с помощью наборов реактивов ЗАО «Вектор-Бест» (Новосибирск). Уровень сывороточных цитокинов: TNF-α, IL-1β, 2, 4, 6, 10 определяли на анализаторе Multiskan EX методом иммуноферментного анализа с использованием наборов «Вектор Бест» (Новосибирск). Подсчет общего количества лейкоцитов произведен классическим способом в камере Горяева, анализ лейкоцитарной формулы - в окрашенных мазках периферической крови. Метаболические изменения оценивали по активности ферментов в ткани печени: щелочной фосфатазы (ЩФ), аланин- и аспартатаминотрансфераз (АЛТ, АСТ), лактатдегидрогеназы (ЛДГ), гаммаглутамилтранспептидазы (γ-ГТ). Активность ферментов определяли унифицированными методами с помощью наборов реактивов ЗАО «Вектор-Бест» (Новосибирск) на фотометре PM-750 (Германия). Гистологические исследования печени осуществляли после декапитации крыс, проводимой под эфирным наркозом. Результаты. Показано, что субхроническое воздействие фторида натрия сопровождается формированием внутриклеточных и внутрисосудистых повреждений печени. Активация медиаторов воспаления и развитие иммунологических нарушений в динамике эксперимента способствуют формированию системной воспалительной реакции, которая приводит к появлению стойких морфологических нарушений в печени и изменению активности ферментов основных метаболических путей. Заключение. Полученные результаты могут быть использованы при разработке и проведении профилактических мероприятий в условиях воздействия на организм высоких концентраций фтора с последовательным применением детоксикационной, иммуномодуляторной и органопротекторной коррекции. Studying mechanisms, which maintain the body homeostasis, is particularly important in the conditions of continuous impact of adverse environmental and manufacturing factors. Long-term exposure to fluorides leads to chronic fluoric intoxication, the pathogenesis of which is a subject of multiple controversy and discussions. Not enough attention is still paid to elucidating the visceral pathology associated with fluorine-induced immune disorders. There are virtually no studies of immune reactions that define the morphofunctional nature of the liver response to early stages of fluoric intoxication. Aim. To study pathophysiological mechanisms of hepatic immune reactivity in subchronic exposure of the body to fluorine compounds. Methods. Experiments were performed on 210 male rats weighing 180-220 g. The animals were divided into two groups: 1) control (n=80) and 2) subchronic exposure to sodium fluoride (n=130). The rats had free access to a 10 mg/l aqueous solution of sodium fluoride (daily dose, 1.2 mg/kg body weight) for 12 weeks. Blood was withdrawn from the caudal vein at 1, 3, 6, 9, and 12 weeks of the experiment for immunological and biochemical tests. Histological study of the liver was performed after decapitation of rats under ether anesthesia. Results. The subchronic exposure to sodium fluoride was associated with intracellular and intravascular damage of the liver. Activation of inflammatory mediators and development of immunological disorders during the experiment contributed to a systemic inflammatory reaction, which resulted in persistent morphological injuries of the liver and changes in enzyme activities in major metabolic pathways. Conclusion. The study results can be used for development and implementation of preventive measures against the effects of high fluorine concentrations, which would include a successive use of detoxification, immunomodulation and organ protection.


2018 ◽  
Vol 18 (2) ◽  
pp. 171-175
Author(s):  
Ashraf A. ◽  
Hassan F. ◽  
Batool S. ◽  
Nadeem M. ◽  
Irshad M. ◽  
...  

The objective of present study was to analyze and compare the nephroprotective effects of petroleum ether extracts of seeds of Nigella sativa and Silybum marianum in Swiss albino mice. Petroleum ether extracts of seeds of Nigella sativa and Silybum marianum were administered (200 mg kg–1) orally for 14 days following one dose of cisplatin injection (16 mg kg–1 i.p.) on 4th day. Cisplatin toxicity was identified in mice by loss of body weight, reduced triglycerides levels, elevated blood glucose, blood urea nitrogen and creatinine levels (P < 0.05). Silybum marianum and Nigella sativa significantly enhanced the body weight (9%) of diabetic rats. Silybum marianum had significantly reduced the elevated blood glucose (–106%), and BUN levels (–9%) as compared to the Nigella sativa administration. Silybum marianum extract also significantly elevated the levels of triglycerides (257%) which were much reduced after the cisplatin injection. Histological study showed that the cisplatin treated group demonstrated the necrosis signs in the glomerulus of Bowman’s capsule, hyalinization and severe cellular damage. The animals administered with extracts showed nearly normal kidney architecture, however, the kidney tissues of Silybum marianum-treated animals showed some improvement with slight signs of cellular damages.


Author(s):  
Nora Goldschmidt ◽  
Barbara Graziosi

The Introduction sheds light on the reception of classical poetry by focusing on the materiality of the poets’ bodies and their tombs. It outlines four sets of issues, or commonplaces, that govern the organization of the entire volume. The first concerns the opposition between literature and material culture, the life of the mind vs the apprehensions of the body—which fails to acknowledge that poetry emerges from and is attended to by the mortal body. The second concerns the religious significance of the tomb and its location in a mythical landscape which is shaped, in part, by poetry. The third investigates the literary graveyard as a place where poets’ bodies and poetic corpora are collected. Finally, the alleged ‘tomb of Virgil’ provides a specific site where the major claims made in this volume can be most easily be tested.


2021 ◽  
Vol 13 (5) ◽  
Author(s):  
Viktória Mozgai ◽  
Bernadett Bajnóczi ◽  
Zoltán May ◽  
Zsolt Mráv

AbstractThis study details the non-destructive chemical analysis of composite silver objects (ewers, situlas, amphora and casket) from one of the most significant late Roman finds, the Seuso Treasure. The Seuso Treasure consists of fourteen large silver vessels that were made in the fourth–early fifth centuries AD and used for dining during festive banquets and for washing and beautification. The measurements were systematically performed along a pre-designed grid at several points using handheld X-ray fluorescence analysis. The results demonstrate that all the objects were made from high-quality silver (above 90 wt% Ag), with the exception of the base of the Geometric Ewer B. Copper was added intentionally to improve the mechanical properties of soft silver. The gold and lead content of the objects shows constant values (less than 1 wt% Au and Pb). The chemical composition as well as the Bi/Pb ratio suggests that the parts of the composite objects were manufactured from different silver ingots. The ewers were constructed in two ways: (i) the base and the body were made separately, or (ii) the ewer was raised from a single silver sheet. The composite objects were assembled using three methods: (i) mechanical attachment; (ii) low-temperature, lead-tin soft solders; or (iii) high-temperature, copper-silver hard solders. Additionally, two types of gilding were revealed by the XRF analysis, one with remnants of mercury, i.e. fire-gilding, and another type without remnants of mercury, presumably diffusion bonding.


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