Ultrastructure of the “fringe-layer”, the innermost epidermis of cotton seed coats

Summary The inner epidermis of the inner integument of cotton seed coats (fringe-layer) and the cuticles between this cell layer and the nucellus were examined in the light and electron microscope at different times of their development. The cells of the fringe-layer contain only small vacuoles and their cytoplasm is densely packed with organelles and free and membrane-bound polysomes. The lateral walls contain many plasmodesmata. At the time when the fruit capsules stop growing, the fringe-cells produce a cell wall labyrinth, resembling that of transfer cells. The cell wall labyrinth is restricted to the lateral walls. The differentiated state of the fringe-cells is short-lived. At about the time of elaboration of the cell wall labyrinth most of them become progressively vacuolated, lignify, and lose their cytoplasmic constituents. The development of the fringe-layer is well correlated with other developmental events in the inner integument, but not with the filling of embryo and endosperm with reserve substances.At anthesis, the fringe-layer and nucellus are covered by a thin cuticle proper of about 20 nm. After anthesis, the nucellar cells start to produce a cuticular layer of considerable, but variable, thickness (0.25–2.5 m), containing a polysaccharide network.In drying seeds the cells of the fringe-layer disrupt. The thin outer tangential wall remains attached to the seed coat. The rest of the cell, together with the cuticles and the collapsed cells of the nucellus, form a protective layer around embryo and endosperm, remaining attached to the seed coat at the chalazal end.     

Ultrastructure of the new neuromuscular junctions formed during reinnervation of rat soleus muscle by a “foreign” nerve

Summary In rats the fast fibular nerve was transposed to the slow soleus muscle outside the original innervation band. Formation of new neuromuscular junctions was induced by cutting the soleus nerve after different periods of time. The morphological maturation of these junctions was studied by electron microscopy.New neuromuscular junctions do not form when the original innervation is left intact.Three to five days after denervation, vesicle-laden terminal boutons contact muscle fibers with only the basal lamina of the latter intervening. Three weeks after denervation, most boutons are larger and postsynaptic folds are present, although younger stages are also seen. Sixteen weeks after denervation, the neuromuscular junctions appear mature. This corresponds well with electrophysiological findings in the same material.The fully developed neuromuscular junctions sixteen weeks after denervation possess postsynaptic folds similar to those of normal fast muscle fibers. This suggests that the fast fibular nerve rather than the slow soleus muscle fibers determines the morphology of the postsynaptic folds.Possible trophic neuromuscular interactions are discussed.The authors are indebted to Mrs. Jorunn Line Vaaland, Miss Bjørg Riber, and Miss Berit Branil for technical assistance. Dr. T. Lømo and Dr. C. Slater have contributed constructive criticism and advice     

Ultrastructure of spermiogenesis inVampyroteuthis infernalis Chun — a relict cephalopod mollusc

Spermiogenesis in the relict deep-sea cephalopodVampyroteuthis infernalis Chun is examined using transmission electron microscopy (TEM), and the results compared with available data on other cephalopods. Early spermatids ofVampyroteuthis exhibit an ovoid nucleus (with dense irregular patches), numerous mitochondria and a pair of triplet substructure centrioles (arranged parallel to each other). Subsequently, the following morphological changes take place: (1) nuclear contents condense into a fibrous reticulum, then into thick fibres; (2) the acrosomal vesicle (presumably Golgi-derived) positions itself in a shallow depression at the nuclear apex; (3) the flagellum forms from one of the two centrioles; (4) mitochondria cluster around the flagellum at the base of the nucleus; (5) a dense, fibrous plug forms within the basal invagination of the nucleus. Microtubules surround the acrosome and condensing nucleus of spermatids. The dense plug is of special systematic importance since it also occurs in spermatids and spermatozoa ofOctopus spp., but not in any investigated species of the Sepiida, Sepiolida or Teuthida. Late spermatids and mature spermatozoa ofVampyroteuthis strongly resemble developing spermatids ofOctopus, suggesting a close phylogenetic relationship betweenVampyroteuthis (and the Vampyromorpha) and octopods.     

Ultrastructure of the “statocysts” inProtodrilus species (Polychaeta): Reconstruction of the cellular organization with morphometric data from receptor cells

Summary The statocysts inProtodrilus ciliatus, P. oculifer, P. haurakiensis andP. helgolandicus are situated in the prostomium anterior to the palps and have been investigated by electron microscopy. The sensory organs were reconstructed from serial sections, volumes were calculated from areas of consecutive section profiles, and additional data on surface area of distal receptor elements have been determined. In spite of variations in size (diameter 8–20 m) their structure is nearly identical. The organs consist of one cup-shaped supportive cell, one large bi- or multiciliated sensory cell and two small uni- or biciliated sensory cells forming an extracellular cavity. This cavity is completely filled with microvillus-like or paracrystalline structures and there are no signs of statoliths composed of extracellular material. The most striking feature is the occurrence of paracrystals made up of undulating ciliary membranes extending from the large sensory cell and occupying 75–90% of the cavity inP. ciliatus, P. oculifer andP. haurakiensis. The remaining space is filled with microvilli or dendritic processes of the sensory cells. InP. helgolandicus the ciliary paracrystals are almost completely replaced by microvillus-like branches of cilia of the corresponding sensory cell. Paracrystals fill less than 10% of the cavity and are formed of flattened membranes. These sensory organs enclose large surface areas of membranes (15,000–38,000 m²). The surface areas of the paracrystals composed of undulating membranes is almost identical to that of densely arranged arrays of microvilli (about 25 m² per m³). These sensory organs are so different from all known statocysts that it is likely that they have another function. Their greatest structural correspondence is to light-receptive organs, especially in the structure and arrangement of microvilli. The role the paracrystals play is discussed: they might bear photopigments or simply represent a lens — a transparent, refractile and crystalline structure. These sensory organs are completely different from pigmented ocelli and phaosomes occurring in some protodrilids and represent a type of sensory organ thus far undescribed in polychaetes.     

Effects of High K+ and Alkaline pH on Ultrastructure of Dunaliella salina Chloroplasts

It was reported that the growth of Dunaliella salina Teod. cultured in medium containing 1 mol/L NaC1 was almost completely inhibited by the addition of 100 mmol/L KC1. The high K+ (100 mmol/L KC1) treatment also significantly inhibited the photosynthetic rate of D. salina and decreased chlorophyll contents in algae. This study focuses on possible effects of high K+ or alkaline pH on the ultrastructural change of chloroplasts in D. salina. After D. salina was cultured in a medium containing 100 n,anol/L KC1 or in a medium with alkaline pH for 8 to 10 days, dramatic ultrastructural changes occurred in the chloroplasts including thylakoid swelling, volume increase of chloroplast, and significant accumulation of starch grains in chloroplasts. The results are consistent with our previous report indicating that the ultrastmctuml changes in chloroplast under high K + or alkaline pH may lead to an inhibitory effects on photosynthesis and overall growth of D. salina.     

Quantification of Collagen Ultrastructure after Penetrating Keratoplasty – Implications for Corneal Biomechanics

Purpose

To quantify long-term changes in stromal collagen ultrastructure following penetrating keratoplasty (PK), and evaluate their possible implications for corneal biomechanics.

Methods

A pair of 16 mm post-mortem corneo-scleral buttons was obtained from a patient receiving bilateral penetrating keratoplasty 12 (left)/28 (right) years previously. Small-angle x-ray scattering quantified collagen fibril spacing, diameter and spatial order at 0.5 mm or 0.25 mm intervals along linear scans across the graft margin. Corresponding control data was collected from two corneo-scleral buttons with no history of refractive surgery. Wide-angle x-ray scattering quantified collagen fibril orientation at 0.25 mm (horizontal)×0.25 mm (vertical) intervals across both PK specimens. Quantification of orientation changes in the graft margin were verified by equivalent analysis of data from a 13 year post-operative right PK specimen obtained from a second patient in a previous study, and comparison made with new and published data from normal corneas.

Results

Marked changes to normal fibril alignment, in favour of tangentially oriented collagen, were observed around the entire graft margin in all PK specimens. The total number of meridional fibrils in the wound margin was observed to decrease by up to 40%, with the number of tangentially oriented fibrils increasing by up to 46%. As a result, in some locations the number of fibrils aligned parallel to the wound outnumbered those spanning it by up to five times. Localised increases in fibril spacing and diameter, with an accompanying reduction in matrix order, were also evident.

Conclusions

Abnormal collagen fibril size and spatial order within the PK graft margin are indicative of incomplete stromal wound remodelling and the long term persistence of fibrotic scar tissue. Lasting changes in collagen fibril orientation in and around PK wounds may alter corneal biomechanics and compromise the integrity of the graft-host interface in the long term.     

The use of Macronet resins to recover γ-decalactone produced by Rhodotorula aurantiaca from the culture broth

During the biotransformation of castor oil into γ-decalactone, R. aurantiaca produced both the lactone form and its precursor (4-hydroxydecanoic acid). After six days of culture, a maximum yield of γ-decalactone of 6.5 g/l was obtained. The parameters of γ-decalactone adsorption on three Macronet resins (MN-202, MN-102 and MN-100) were investigated in water. Adsorption isotherms of γ-decalactone for the three Macronet resins were linear. The trapping of γ-decalactone produced by R. aurantiaca on these resins was then carried out. γ-Decalactone was effectively retained by all the studied Macronet resins. The resin MN-202 trapped γ-decalactone more efficiently than MN-102 and MN-100. The percentages of γ-decalactone adsorbed on the resins MN-202, MN-102 and MN-100 were, respectively, 85, 75 and 81%, whereas around 70% of the adsorbed γ-decalactone was then desorbed. We propose an industrial process that uses Macronet resins to extract γ-decalactone from culture broth of R. aurantiaca.     

Ultrastructure of the male reproductive organs in the interstitial annelid Sphaerosyllis hermaphrodita (”Polychaeta”, Syllidae)

 The reproductive organs of the simultaneous hermaphrodite Sphaerosyllis hermaphrodita (Syllidae, Exogoninae) were examined by TEM and reconstructed from ultrathin serial sections. Oocytes are produced in the 11–13th chaetigerous segments and then attached to the outer body surface. The male organs comprise a seminal vesicle, testes, sperm ducts and copulatory chaetae. The unpaired seminal vesicle is an uncompartmented cavity above the gut and within the chaetigerous segments 8–10. Its interior is lined with a layer of gland cells that degenerate as spermatogenesis in the vesicle proceeds. The testes are situated ventrolaterally, close to the seminal vesicle in the 9th chaetigerous segment. They contain cells at early stages of spermatogenesis, which are connected to one another by zonulae collares. The testes and seminal vesicle are enclosed in epithelia. Paired sperm ducts run ventrally from about the midline of the body under the seminal vesicle and into the parapodia of the 9th chaetigerous segment. There they open, together with the protonephridia of this segment, to the outside next to the stout copulatory chaeta. Each sperm duct consists of six cells, the luminal surface of which bears microvilli but no cilia. Only in animals with fully differentiated sperm does the small opening of the proximal duct cell in each duct give access to the seminal vesicle. The mode of sperm transfer is discussed. Accepted: 9 December 1996     

Effects of Glycerol on the Fluorescence Spectra and Chloroplast Ultrastructure of Phaeodactylum tricornutum （Bacillariophyta）

Responses of the photosynthetic activity of Phaeodactylum tricornutum （Bacillariophyta） to organic carbon glycerol were investigated. The growth rate, photosynthetic pigments, 77 K fluorescence spectra, and chloroplast ultrastructure of P. tricornutum were examined under photoautotrophic, mixotrophic, and photoheterotrophic conditions. The results showed that the specific growth rate was the fastest under mixotrophic conditions. The cell photosynthetic pigment content and values of Chl a/Chl c were reduced under mixotrophic and photoheterotrophic conditions. The value of carotenoid/Chl a was enhanced under mixotrophic conditions, but was decreased under photoheterotrophic conditions. In comparison with photoautotrophic conditions, the fluorescence emission peaks and fluorescence excitation peaks were not shifted. The relative fluorescence of photosystem （PS） Ⅰ and PS Ⅱ and the values of F685/F710 and F685/F738 were decreased. Chloroplast thylakoid pairs were less packed under mixotrophic and photoheterotrophic conditions. There was a strong correlation between degree of chloroplast thylakoid packing and the excitation energy kept in PS Ⅱ. These results suggested that the PS Ⅱ activity was reduced by glycerol under mixotrophic conditions, thereby leading to repression of the photosynthetic activity.     

Ultrastructure and elemental composition of the eggshell of Reeve’s pheasant (Syrmaticus reevesii)

The eggshell of Reeve's pheasant (Syrmaticus reevesii) collected from the Dongzhai National Nature Reserve in Henan Province,China was studied.By using scanning electron microscopy and inductively coupled plasma (ICP) spectrometry,the ultrastructure and elemental composition of the eggshell was determined.The study showed that the average thickness of the surface layer of crystals,the palisade and cone layer,and the eggshell membrane were 20.8,220.8 and 62.5 larn,respectively,accounting for 6.8%,72.6% and 20.6% of the total thickness of the eggshell.There were many vesicular holes in the palisade layer with an average diameter of 0.32±0.08 μm(n = 30).The function of these holes might be significant to air exchange.The shape of the eggshell pore on the surface layer of crystals is round or elliptical.The fracture surface of the pore is funnel-shaped.Some granules filled the upper part of the eggshell pores.The content of 21 elements in the eggshell of wild and captive Reeve's pheasants was compared and presented.It indicated that among the elements that made up the eggshell of the wild pheasant,the content of Ca,Mg,P and S was much higher,ω＞ 1 mg/g,with ω (Ca) being higher than 40% of the eggshell.The contents of Na,Si,Sr,K and A1 were ω = 0.1-1 mg/g,while Fe,Zn,Pb,Mn,Cu,V and Ti had lower concentrations (ω = 1-100 μg/g).The ω ofNi,Cr,Co,Se,Cd were lower than 1 μg/g.The elemental composition in the eggshell of the captive Reeve's pheasant kept in the Dongzhai National Natural Reserve was significantly different from that of the wild species,with a difference of over 20% on S,Cu,Fe,AI,Mn,Si,Sr,Se and Cr.The lower intake of Fe,Mn,Si and Sr on the one hand and the higher intake of S,Cu,Al and Cr on the other hand might be responsible for the low fertility of captive Reeve's pheasants in the Dongzhai National Nature Reserve.In order to ensure that the pheasants are receiving the proper amount of nutrition and to improve their breeding success,the amount of certain elements in the food should be adjusted.     

Ultrastructure of the rickettsial endosymbiont “MIDORIKO” in the green alga Carteria cerasiformis as revealed by high-pressure freezing and freeze-substitution fixation

Bacterial endosymbionts belonging to the family Rickettsiaceae were recently identified in the unicellular green alga Carteria cerasiformis, providing the first molecular evidence of rickettsial endosymbionts within photosynthetic eukaryotes. However, previous morphological studies using transmission electron microscopy (TEM) with conventional chemical fixation did not demonstrate whether the endosymbionts of C. cerasiformis have the diagnostic characteristics of the family Rickettsiaceae. In this study, we observed the rickettsial endosymbionts “MIDORIKO” within C. cerasiformis cells by TEM with high-pressure freezing and freeze-substitution fixation. The rickettsial endosymbionts resided directly in the C. cerasiformis cytoplasm without engulfing or encompassing membranes or vacuoles. The endosymbionts had a Gram-negative cell envelope composed of outer and inner bilayer membranes. The thicknesses of the outer and inner leaflets of the bacterial cell wall were almost identical. These morphological characteristics are consistent with those of the genus Rickettsia, but the cell wall structure differed from that of the genus Orientia within the family Rickettsiaceae.     

Ultrastructure de l'endomètre humain normal

Résumé L'étude du chorion cytogène de 15 endomètres humains normaux prélevés à divers moments du cycle menstruel a précisé d'importantes variations des vaisseaux et des cellules.Les vaisseaux subissent une maturation progressive: en phase proliferative moyenne, des pointes d'accroissement se forment à partir du réseau vasculaire profond activé; au milieu du cycle, elles se transforment en capillaires typiques; en phases sécrétoires moyenne et avancée, des péricytes migrent dans le chorion cytogène et se différencient en cellules choriales.Ces cellules choriales, dites fixes, ont une évolution biphasique au cours du cycle menstruel. Au milieu de chacune des phases, proliférative et surtout sécrétoire, les cellules choriales fixes, dites alors fibroblastoïdes, montrent une intense activité de synthèse. A ces périodes de synthèse succède une involution cellulaire, peu marquée en fin de phase proliferative, intense en phase sécrétoire avancée.Les cellules dites prédéciduales sont des cellules choriales fixes involuées et hyperhydratées; elles vont, en phase menstruelle, évoluer de plusieurs façons: la plupart d'entre elles régénèrent, certaines se nécrosent focalement ou totalement, d'autres font preuve d'activité macrophagique, en particulier collagénolytique.

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Ultrastructure of the normal human endometriumI. The stroma

Summary 15 human endometria during the normal menstrual cycle have been investigated. Important alterations of the vessels and the stroma cells occur.The vessels are the site of gradual maturation. In the mid proliferative phase, growing capillaries rise from the deep-seated vascular system. In the middle of the cycle, they change into typical capillaries. In the mid and late secretory phases, pericytes leave the walls of the capillaries and differentiate into stroma cells.These stroma cells undergo a biphasic cyclic evolution. The middle of the proliferative and particularly of the secretory phase is marked by an intensive synthetic activity of the stroma cells which are called, at this time, fibroblastoïd stroma cells. These two periods of synthesis are followed by cellular involution, mild in the proliferative, intense in the secretory phase.The so-called predecidual cells are hyperhydrated involuted stroma cells. In the menstrual phase they behave very differently of: the majority regenerates, some predecidual cells are the site of focal or total necrosis, others show a macrophagic activity which is conspicuous in some cells having a collagenolytic activity.

Nous remercions Monsieur le Professeur Gandar, Directeur de la Clinique Gynécologique et Obstétricale 1 de la Faculté de Médecine de Strasbourg de nous avoir confié, pour examen ultrastructural, le matériel nécessaire à cette étude.     

The dynamics of the Liverpool taxi-cab population 1971—78

The number of licensed taxi-cabs in Liverpool rose from about 300 in 1971 to about 900 in 1978. Mark-release-recapture methods gave a reasonable assessment of this change and age distributions showed that it was due to large numbers of young ‘animals’ entering the population.     

Are the most numerous sensilla of terrestrial isopods hygroreceptors? Ultrastructure of the dorsal tricorn sensilla of Porcellio scaber

The ultrastructure of the tricorn sensilla of the woodlouse Porcellio scaber was investigated in cryofixed and freeze-substituted, or chemically fixed specimens. The tricorn sensilla have a foramenized triangular-shaped outer hair and bear a poreless rod-like inner hair. The conical base of the inner hair is connected to the base of the outer hair by a complex cuticular structure. Each sensillum contains three sensory cells. The tip of one of the three dendrites contains a tubular body and is clamped between two bulges of the dendritic sheath. The two other dendrites protrude to the tip of the inner hair, flush against the cuticular wall. The microtubules in the ciliary segments are arranged in nine double tubuli that have neither osmiophilic cores nor arms. The ciliary rootlets are small. The inner segment of the largest dendrite wraps around the two smaller dendrites and one of seven enveloping cells in a mesaxon-like manner. Although this ultrastructure deviates considerably from most crustacean mechanosensitive sensilla, it nevertheless suggests a mechanosensitive function, at least for one of the sensory cells. In many aspects, the tricorn sensilla resemble the thermohygrosensilla of insects. However, our results suggest that the structural criteria for thermo-hygro-sensitivity used in insects cannot simply be applied to crustaceans.     

Ultrastructure de l'endomètre humain normal

Résumé Les auteurs ont étudié les variations morphologiques et métaboliques de 15 endomètres humains normaux prélevés à diverses phases du cycle menstruel.En phase proliférative, les cellules glandulaires ont une activité métabolique de synthèse endogène et acquièrent un important complexe ergastoplasmo-golgien.En phase sécrétoire débutante le glycogène s'accumule dans les cellules glandulaires; son catabolisme fournira les réserves métaboliques nécessaires à l'intense activité de synthèse dont font preuve les cellules glandulaires en phase sécrétoire moyenne.Le matériel synthétisé, présumé mucopolysaccharidique, apparaît dans des vacuoles golgiennes qui migrent ensuite vers le pôle apical de la cellule.L'involution débute dès le 24ème jour et se traduit par la régression de l'activité de synthèse, par l'apparition de foyers autophagiques puis par une hyperhydratation cellulaire.En phase menstruelle certaines cellules se nécrosent totalement, d'autres (les plus nombreuses) régénèrent et participent à un nouveau cycle menstruel.

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Ultrastructure of the normal human endometriumII. The glandular cells

Summary The authors have studied the cyclic morphologic and metabolic variations of 15 normal human endometria.In the phase of proliferation, the glandular cells have a metabolic activity of endogen synthesis and acquire welldeveloped ergastoplasm and Golgi-complexes.In the early phase of secretion, glycogen deposits appear in the glandular cells. Their catabolism will provide the metabolic reserves necessary for the intense synthesis occuring in the glandular cells during the mid secretory phase.The synthezised material — probably mucopolysaccharidic — appears first in Golgi vacuoles which migrate then towards the apical pole of the cell.The cellular involution begins on the 24th day and is characterized by the regression of the synthesis activity, by the appearance of focal necrosis and then by cellular hyperhydratation.In the menstrual phase, while some of the cells undergo total necrosis, others, the majority, regenerate and will participate in a new menstrual cycle.

Nous remercions Monsieur le Professeur Gandar, Directeur de la Clinique Gynécologique et Obstétricale 1 de la Faculté de Médecine de Strasbourg de nous avoir confié, pour examen ultrastructural, le matériel nécessaire à cette étude.     

Ultrastructure of the dendritic outer segments of sensory cells in poreless (‘no-pore’) sensilla of insects

Summary Poreless sensilla with inflexible sockets in insects presumably house hygro- and thermoreceptors (type-1, type-2 receptors). The dendritic outer segments of these receptor cells were studied mainly in cryofixed antennae of two species of moth (Antheraea pernyi, A. polyphemus) and one beetle (Aleochara curtula). As a rule two type-1 receptor cells are present. Their dendritic outer segments do not branch. They project into the distal cuticular parts of the sensillum and are in close contact with its four-layered wall. The segments differ in shape and microtubule density. As well, in A. curtula, the microtubules are interconnected by electron-dense material for some distance, thus forming a tubular body-like structure of 1.3 m length. The dendritic outer segment of the single type-2 receptor cell is branched and lamellated. Its lamellae are connected by structures similar to septate junctions, which occupy about 70% of the total surface of the lamellated portion of the dendrite. In tangential sections, the septa appear as parallel strands approximately perpendicular to the long axis of the dendritic segment. The structure of type-1 receptors is discussed with regard to the hypothesis for a mechano-electrical transduction. The possible functions of lamellation and junctional connections in type-2 receptors are discussed.Supported by the Deutsche Forschungsgemeinschaft (SFB 4/G1)     

Ultrastructure of spermatozoa of Solifuges (Arachnida, Solifugae): possible characters for their phylogeny?

The ultrastructure of spermatozoa is a widely accepted source of characters for phylogenetic studies. In this study the fine structure of sperm cells of representatives of six different New and Old World families (Ammotrechidae, Daesiidae, Eremobatidae, Galeodidae, Karschiidae, Solpugidae) of solifuges (Arachnida, Solifugae) were investigated in order to reveal putative characters suitable for subsequent systematic and phylogenetic analyses. The spermatozoa of solifuges represent a relatively simple type of sperm cells. In general, their spermatozoa are roundish, oval shaped (Ammotrechidae, Daesiidae, Eremobatidae, Solpugidae) or plate-shaped (Karschiidae) with or without membrane protuberances and devoid of a flagellum. Only in Galeodidae, very conspicuous thin and elongated sperm cells occur. The spermatozoa either occur as single cells (Eremobatidae, Solpugidae) or in groups of loose knit cells (Ammotrechidae) or in highly ordered groups (Karschiidae). In contrast to the other families studied here, within the Galeodidae and in the genus Blossia (Daesiidae) sperm cells surrounded by a secretion sheath, clearly representing coenospermia, could be observed.     

Ultrastructure of the spore in four Japanese species of Ptychomitrium Fürnr. (Musci)

The ultrastructure of the mature spore in four Japanese species of the acrocarpous moss genus Ptychomitrium is presented. In all species the spores have a similar pattern: there is no recognisable aperture nor sporoderm polarity, exine and perine are poorly developed, cytoplasm only occasionally shows polarity, and plastids have a well developed inner membrane system. The presence of frequent intine protrusions is a remarkable feature of this genus. A multilaminar structure of the exine, already observed in Grimmia, occurs also in these species although here it is less pronounced. The significance of these features is discussed within these species, as well as in comparison to other taxa, especially the genus Grimmia.