Studies of the reproductive physiology of Cimicidae (Hemiptera)—II. Artificial insemination and the function of the seminal fluid

Cimex lectularius L. was artificially inseminated by injecting sperm and seminal fluid into the spermalege. The fecundity of females inseminated in this way is about the same as normally inseminated females. Insemination may be made directly into the haemocoele but the resulting mortality is high. Seminal fluid is essential in insemination; without it spermatozoa do not migrate. Spermatozoa in seminal fluid in vitro become active and aggregate into dense masses from which the tails extend and move actively. The waves originate at the end of the tail and move towards the head. In vitro activity of the sperm resembles that observed in vivo. Spermatozoa can be activated in 0·07 M sodium citrate containing seminal fluid. Seminal fluid of various other cimicids can activate the sperm of C. lectularius. Artificial insemination may be done using activated sperm masses washed free of seminal fluid. The principal function of the spermalege is probably to hold the semen until activation occurs. Once activated the sperm pass through the haemocoele as a mass. Injection of activated sperm masses into the haemocoele is usually harmless and results in fecundation. Injection of unactivated sperm into the haemocoele often results in the death of the female and no eggs are produced. Eggs do not mature unless spermatozoa reach the upper part of the reproductive tract; this region is probably the source of the stimulus activating the corpus allatum.     

The maxillary palp of Drosophila : ultrastructure and physiology depends on the lozenge gene

The ultrastructure and physiology of the maxillary palp of Drosophila melanogaster have been studied in wild-type and lozenge mutants. Olfactory physiology in the maxillary palp is shown to depend upon the lozenge(lz) gene. Reduced response amplitudes were recorded for all odorants tested, and the physiological defect was shown to map to the lz locus. The structure of the maxillary palp sensilla is described by scanning electron microscopy (SEM) at high magnification, initially in the wild-type. A linear arrangement of pores, connected by furrows, was found in one class of sensilla, the basiconic sensilla. In the lz ³ mutant, morphological alterations in the basiconic sensilla and duplications of sensilla are documented by SEM. The correlation of structural abnormalities in the lz sensilla and physiological abnormalities in odorant response are consistent with an olfactory role for the basiconic sensilla of the maxillary palp. Accepted: 10 September 1996     

The cave bear’s hibernation: reconstructing the physiology and behaviour of an extinct animal

Abstract

When studying an extinct species such as the cave bear (Ursus spelaeus ROSENMÜLLER 1794), it is possible to apply a variety of molecular biology techniques such as the study of stable isotopes or mitochondrial DNA (mDNA) to infer patterns of behaviour or physiology that would otherwise remain concealed. Throughout Europe and along time, differences in the isotopic values (δ¹³C and δ¹⁵N) of cave bears arise from environmental differences and the Pleistocene climatic evolution. The climate determines the hibernation length, during which the cave bears undergo a particular physiology that can be related to an increase in δ¹⁵N during climate cooling. In order to verify whether hibernation affected the isotopic values, we compared cave bears in different ontogenetic stages. The results show that perinatal values reflect the values for mothers during hibernation, while juveniles show differences in maternal investment. A previous study in the literature based on complete mitochondrial DNA sequences of several individuals collected from closely situated caves showed that each cave housed, almost exclusively, a single lineage of haplotypes. This pattern suggests extreme fidelity to the birth site, or homing behaviour, and that cave bears formed stable maternal social groups, at least for the purpose of hibernation. Studies of this type offer unexpected data on the palaeobiology of this extinct animal.     

Centers and peripheries: The development of British physiology, 1870–1914

Conclusions By 1910 the Cambridge University physiology department had become the kernel of British physiology. Between 1909 and 1914 an astonishing number of young and talented scientists passed through the laboratory. The University College department was also a stimulating place of study under the dynamic leadership of Ernest Starling.I have argued that the reasons for this metropolitan axis within British physiology lie with the social structure of late-Victorian and Edwardian higher education. Cambridge, Oxford, and University College London were national institutions attracting students from all over England and Wales. In contrast, the provincial colleges drew their clientele from relatively narrow geographic radii. Generally, also, these institutions were regarded as socially inferior to the longer-established universities.A brief survey of the biographies of some British physiologists demonstrates how physiology, as an occupation, became, over the later decades of the century, socially elite. The scientists who achieved full-time posts in the 1870s generally came from somewhat marginal backgrounds. Foster, like his mentors T. H. Huxley and William Sharpey, came from a non-conformist family. Edward Schäfer was also a dissenter and, like Foster, began his professional career as a general practitioner.Physiologists of the succeeding generation, however, came from wealthy families with established intellectual traditions. John Scott Haldane, nephew of John Burdon Sanderson, was the brother of the politician R. B. Haldane and uncle of the historian A. R. B. Haldane.⁷¹ Joseph Barcroft was one of the most affluent of all physiologists.⁷² His family's wealth derived from linen manufacturing. He attended the Ley's School Cambridge, where his schoolmates included Henry Dale, later Director of the National Institute for Medical Research; F. A. Bainbridge, who eventually became Professor of Physiology at St. Bartholomew's Hospital; and the Cambridge historian J. H. Clapham. A. V. Hill, Professor of Physiology at Manchester and, subsequently, London, married Margaret Keynes, sister of John Maynard Keynes and niece of Sir Walter Langdon Brown, Professor of Physic at Cambridge. Margaret Keynes's younger brother, the surgeon Sir Geoffrey Keynes, married a granddaughter of Charles Darwin; their son Richard Keynes also became a physiologist at Cambridge.These families were part of a new class emerging during the late Victorian period, descendants of the great reforming radicals of the 1830s, who had begun to achieve power through positions in the universities, the professions, and the civil service. Their social prestige rested upon their intellectual expertise. Physiology was an appealing research discipline to these groups because of its clear dissociation from industry and commerce. And because physiology's practical face was medicine, its acceptability was reinforced by professional ties.The nature of the Physiological Society confirms this image of physiology as an elite science. By the turn of the century the Society had taken on some of the characteristics of a dining club. The scientific meetings were generally followed by dinner: if the Society met at Oxford, they were entertained at Burdon Sanderson's college, Magdalen.⁷³ Through a black ball system, unwanted candidates could be excluded. In 1912, when the question of admitting foreigners was discussed, E. H. Starling wrote to Edward Schäfer: the Society has very much in it the nature of a club, and a certain amount of personal knowledge of the candidate is always desirable.⁷⁴.The developing institutional structure of physiology in late Victorian Britain indicates, therefore, that we must look beyond the achievements of individuals and departments to understand why physiology flourished. The discipline became part of a new social order in which the professional middle classes assumed increasing power. These groups valued intellectual skill, especially in the pure scienes, as forces both for self-advancement and for progress within society.     

Morphology and anatomy of the Cephalocereus columna-trajani cephalium: why tilting?

The morphology and anatomy of the Cephalocereus columna-trajani flowering region was described and compared with data on other species. The vegetative and reproductive regions were described in detail. The results showed that after the flowering region is differentiated, morphological changes take place which are correlated with anatomical changes. The flowering region in this species is termed a lateral cephalium because of its reduced interareolar space, increased areole size and abundant long bristles and trichomes in the areoles. Periderm development near the apical meristem, lack of chlorenchyma and a delay in xylem fiber differentiation are also traits characteristic of a lateral cephalium. The lateral cephalium of C. columna-trajani shared the same combination of morpho-anatomical characters with its sister taxon, C. senilis, except for the number of ribs in the cephalium. Both species survive in high temperature environments and their cephalium faces north; however, only C. columna-trajani tilts, thus we hypothesize that incorporation of fewer ribs associated with periderm development in the cephalium contributes to stem tilting.     

Biosynthesis of the alkaloids of Chelidonium majus—II. : The formation of chelidonine from stylopine

The tetrahydroprotoberberine alkaloid, stylopine, has been synthesized with carbon-14 label at C-6. The chelidonine isolated from Chelidonium majus L. plants which had been fed dl-stylopine-6-¹⁴C was radioactive (0.7%, incorporation), and systematic degradation established that all the activity was located at C-11. This result provides strong support for the hypothesis that the tetrahydroprotoberberines are precursors of the benzo[c]phenanthridine alkaloids.     

The microscopic anatomy and ultrastructure of the nephridium of the sipunculan Themiste hexadactyla Satô 1930) (Sipuncula: Sipunculidea)

The microscopic anatomy and ultrastructure of the nephridia of the sipunculan Themiste hexadactyla (Satô, 1930) from the Sea of Japan were studied by the histological and electron microscopic methods. The fine structures of the ciliary funnel, muscular “tongue,” excretory sac, and excretory tube of the nephridium were described. The ultrastructural features of the excretory epithelium, cupola-shaped epithelial infoldings, excretory canals, and muscular layer in the extracellular matrix of the nephridial wall were examined and described in detail. The ultrastructure of the nephridial coelomic epithelium composed of podocytes with long processes and multiciliary cells was also examined and illustrated. Characteristic cell contacts between the processes of podocytes, viz., paired “double diaphragms,” were described and illustrated for the first time.     

The carotenoids of blue-green algae—II. : The carotenoids of Aphanizomenon flos-aquae

The carotenoid composition of Aphanizomenon flos-aquae has been re-examined in a quantitative manner. The epiphasic fraction comprised β-carotene (I), flavacin, aphanin and aphanicin. The last two were shown to be identical with echinenone (IV) and canthaxanthin (VI) respectively. The hypophasic fraction contained in addition to aphanizophyll small amounts of myxoxanthophyll. Aphanizophyll and myxoxanthophyll are different pigments.     

The polyphenols of Nothofagus species—II.: The heartwood of Nothofagus fusca

From the heartwood of Nothofagus fusca were isolated taxifolin, catechin, aromadendrin, quercetin, kaempferol, naringenin, ellagic acid, gallic acid, resveratrol, 3,3′-di-O-methyl ellagic acid and a compound “nothofagin” with properties consistent with those of a mono-C-glycoside of 4,2′,4′,6′-tetrahydroxy-dihydrochalcone. Another compound “konnanin” appears to be a C-glycoside of 3,4,2′,4′,6′-pentahydroxy-dihydrochalcone. Afzelechin, epicatechin, protocatechuic acid, p-hydroxybenzoic acid and phloroglucinol have been identified chromatographically. The possible taxonomic significance of the dimethyl ellagic acid is discussed. Spectral and chromatographic properties of the known dihydrochalcones are described.     

Some mathematical aspects of chemotherapy—II: The distribution of a drug in the body

In a previous paper (Bellman, Jacquez, and Kalaba,Bull. Math. Biophysics,22: 181–198, 1960) a model of the processes occurring in the exchange of a drug between capillary plasma, extracellular space and intracellular space was developed. This included the possibility of a reaction between the drug and a component of the intracellular space. The equations developed thus describe the events within a capillary bed. In the present paper, a simplified model of the body is set up. Each organ is treated as a single capillary bed and is linked to other organs via the circulation, in the parallel and/or series arrangements found in the body. Mixing in the circulation is included at the simplest possible level. The concentration of drug entering any one capillary bed is determined by the concentrations leaving all other capillary beds, the time lags, and mixing involved in the circulation. The equations describing these processes in conjunction with the equations of the processes occurring within each capillary bed lead to a large set of differential-difference equations.