Numerous Golgi Complexes Research Articles

An Ultrastructural Study of Tegumental Glands of the Fifth Pereiopods of Aegla Platensis (Anomura: Aeglidae)

Abstract Tegumental glands are a ubiquitous feature of the decapod cuticle. In the fifth pair of pereiopods (P5) of Aegla platensis Schmitt, 1942, these tegumental glands (PeTG's) are similar to those described in other decapod crustaceans. Type 1 PeTG's, with mucous and serous cells and type 2 PeTG's, with serous cells only are organized into proximal, medial and distal clusters along the appendage. Both types of PeTG's possess secretory cells arranged concentrically around a central duct. These secretory cells have well developed Rough endoplasmic reticulum (RER) and numerous Golgi Complexes, and possess electron-lucid and electron dense vesicles. The finely granular aspect of the electron-lucid vesicles suggest they contain a mucous-like substance, while electron-dense vesicles probably contain a substance of a proteinaceous nature. Despite various hypotheses, there are few indications that these substances act as cleaning agents. However, the cytoplasm of the secretory cells appear to be composed of c...

Ovaries of Petrobius brevistylis (Archaeognatha, Machilidae) and Tricholepidion gertschi (Zygentoma, Lepidotrichidae): Morphology, ultrastructure and phylogenetic implications

Summary The ovaries of Petrobius brevistylis (Archaeognatha) and Tricholepidion gertschi (Zygentoma) are composed of seven metamerically arranged panoistic ovarioles that are covered with the external epithelial sheath (=tunica externa) and the basal lamina (=tunica propria). The germaria are small and enclose oogonial cells and somatic prefollicular cells. The vitellaria contain 10–15 linearly arranged oocytes that are surrounded by a one-layered follicular epithelium. Oocyte nuclei (=germinal vesicles) are large and possess giant, compact ( P. brevistylis ) or lobate ( T. gertschi ) nucleoli. In both studied species the majority of yolk is incorporated to the oocyte via endocytosis; however, appearance of numerous Golgi complexes and rough endoplasmic reticulum cisternae at the onset of vitellogenesis suggests the involvement of these organelles in synthesis of yolk precursors. The obtained results are discussed in the phylogenetic context and support the idea that Lepidotrichidae are the most basal zygentoman clade.

Structural Characteristics of Cardiomyocytes in the Right Atrium of NISAG Rats

Electron microscopy and stereomorphometric analysis of hypertrophic cardiomyocytes in the right atrium of NISAG rats revealed signs of activation of biosynthetic processes: increased relative volume of euchromatin (compared to Wistar rats), high density of nuclear pores, presence of large numerous Golgi complexes, and well-developed endoplasmic reticulum. The numerical density of secretory granules in the cytoplasm of cardiomyocytes in NISAG rats significantly surpassed that in Wistar rats. However, these granules in NISAG rats were smaller than in Wistar rats. The presence of numerous secretory granules and increased ratio of forming and dissolving structures suggest that this pool is characterized by high turnover rate, i.e., intensive synthesis and rapid elimination (consumption) of natriuretic peptide. Hypertrophy and hyperactivity of endocrine function in atrial cardiomyocytes of NISAG rats can be considered as a compensatory reaction to hypertension.

Morphological features of different regions in frog crista ampullaris (Rana esculenta).

The cellular organization of different regions of the crista epithelium from the frog posterior semicircular canal was studied by light, transmission and scanning microscopy. The sensory epithelium consists of hair cells surrounded by supporting cells and basal cells located close to the basement membrane. Three types of hair cells, namely club-like, cylindrical and pear-like cells differentially distributed along the crista could be recognized on the basis of their shape. Club-like cells are located only in the peripheral regions, cylindrical cells both in the central and in the peripheral regions, and pear-like cells appear segregated into the intermediate regions. Sensory cells of the central region are characterized by a ciliary apparatus consisting of stereocilia usually shorter--and in some cases less numerous--than those of cells of the other regions. The presence of large evaginations of the apical membrane of hair cells and of several vesicles of microexocytosis demonstrates that receptor cells have a considerable secretory activity. This secretory activity is also proven by the presence in the supranuclear region of hair cells of numerous Golgi complexes. Moreover, the presence of two kinds of Golgi complexes, one constituted by dilated cisternae containing a moderately electron-dense material and the other made up of flattened electron-transparent cisternae, suggests a diversified secretion of material by the hair cells. This heterogeneous material may provide substances important for cupula formation and the composition of the endolymph.

Ultrastructure of growing oocytes and accessory cells in Austrognathia (Gnathostomulida, bursovaginoidea)

The ovary of Austrognathia cf. riedli consists of 4–6 oocytes which are located in the mid-body region between the epidermis and the gut epithelium. The ovary is not enveloped by a tunica and each growing oocyte is surrounded by one or more accessory cells, the function of which is hypothesized in this study. Oogenesis is not synchronous and can be subdivided into a previtellogenic phase and a vitellogenic phase. Previtellogenic oocytes undergo a number of cell differentiations which consist mainly of an increase in size of the nucleus and nucleolus and the appearance in the cytoplasm of chromatoid bodies, annulate lamellac and short cisternae of rough endoplasmic reticulum (RER). Vitellogenic oocytes are characterized by the increase of RER, the appearance of numerous Golgi complexes and the accumulation of electron-dense globules, glycogen and lipid droplets. The electron-dense globules have been interpreted as yolk on the basis of both their localization and composition. Yolk synthesis occurs mainly by an endogenous mechanism and, to a lesser extent, by micropinocytosis. No shell-granules have been identified in the oocytes. The present ultrastructural findings are discussed in comparison with those from other lower metazoans.

The fine structure and possible functions of scolex gland cells inTrilocularia acanthiaevulgaris (Cestoda, tetraphyllidea)

The ultrastructure of the scolex glands ofTrilocularia acanthiaevulgaris is described with the aid of transmission electron microscopy. The syncytial scolex gland cells exhibit an ultrastructure which is typical of secretory cells, in that they contain extensive and distended cisternae of granular endoplasmic reticulum (GER), numerous Golgi complexes and secretory vesicles. The vesicles are transported via microtubule-lined ducts to the apex of the scolex where they are released from the tegumental surface by an eccrine process. The secretion is often accumulated in reservoirs created by a lateral swelling of the ducts. Cytochemical studies show that the secretion has a glycoprotein nature. It is suggested that the secretion probably acts as an adhesive, aiding attachment of the worm to the host mucosa. This may be more important in juvenile worms which have less well-developed scoleces.

A persistent, TTX-sensitive sodium current in an invertebrate neuron with neurosecretory ultrastructure

In the CNS of the giant barnacle (Balanus nubilus) a single pair of large neuronal somata (cross-commissural, or CC, cells), located near the entry of the median ocellar nerve, occasionally displays a prominent whitish luster. These somata have ultrastructure typical of neurosecretory cells: numerous Golgi complexes and abundant, large dense-cored vesicles (DCVs; size range, 75-275 nm). Injection of a CC cell with cobalt tracer shows that it arborizes over a 7 mm length of the contralateral peripheral nerve out of which it projects. The processes of the arbor are profuse and varicose; the varicosities are packed with DCVs similar to those in the soma. Stimulation of a single CC cell causes a substantial decrease in the number of DCVs and increases the incidence of clusters of small electron-lucent vesicles, as well as the occurrence of large electron-lucent vesicles and membrane-bound cisternae. We studied ionic currents flowing across this cell's somatic membrane with a single-electrode voltage clamp. Unusual among these currents is an inward current that is blocked by TTX but is essentially noninactivating. In current clamp, this "persistent" current causes the action potential to be prolonged (seconds) if opposing outward current is blocked with 4-aminopyridine. The inward current is carried by Na. Its amplitude depends on the external Na concentration, it is blockable by TTX, and it persists when the cell is bathed in Ca-free saline and/or Co. Other currents present in this cell include an outward current similar to molluscan A-current and a Ca current that contributes to the action potential (Stockbridge and Ross, 1986). The persistent Na current is partially activated at the cell's resting potential and, thus, may participate in determining the frequency of its impulse activity.

An Ultrastructural and Immunocytochemical Study of Gastrodermal Cell Types in Microstomum lineare (Turbellaria, Macrostomida)

AbstractThe gastrodermal cell types of Microstomum lineare (Turbellaria, Macrostomida) were studied by electron microscopy. Their immunoreactivity (IR) to bovine pancreatic peptide (BPP), FMRF‐amide and vasotocin, somatostatin, neurotensin, ACTH, CCK, bombesin, secretin, gastrin/CCK and insulin antisera was tested by light microscopic immunocytochemical methods. In addition to granular club cells and phagocytic cells, neurons and neoblasts occur in the gastroderm of this turbellarian species. This is the first observation of neurons in the gastroderm of a flatworm. Dense‐core vesicles (70–100 nm diameter), electron lucent cytoplasm and numerous Golgi complexes characterize the neurons. Unpolarized two‐way synapses, neuromuscular junctions and polarized chemical synapses can be observed in the gastroderm. Neoblasts with large nuclei and scanty cytoplasm and differentiating cells containing clusters of basal bodies occur next to the basal lamina of the gastroderm. BPP‐like, FMRF‐amide‐like and vasotocin‐like immunoreactivity is demonstrated in the gastroderm. Both BPP and FMRF‐amide IR is restricted to the basal cytoplasm of the granular club cells, while a different location for IR to vasotocin antiserum is observed. The status of the neuronal cell in the gastroderm of M. lineare is discussed in relation to endocrine (paracrine) cells and neurons in the gastroderm of invertebrates.

Altered Purkinje cell maturation in rats exposed prenatally to ethanol: I. Cytology

Sprague-Dawley pregnant rats received a liquid ethanol diet that was nutritionally balanced and provided 35% of calories in ethanol, beginning on day 6 of gestation. Control animals were pair-fed the same diet except that maltose-dextrins were substituted for ethanol. At birth pups of both ethanol-exposed and pair-fed groups were fostered by surrogate mothers which received normal rat chow ad libitum. An average of eight alcohol-exposed and eight pair-fed pups were killed at 0–1, 5, 7, 10, 14, 21, 28, and 42 days. Their fixed cerebella were bisected in the midvermal plane and one-half embedded in Araldite. Thin sections were cut from lobules II III and stained with uranyl acetate and lead citrate and visualized with the electron microscope to evaluate the effect of ethanol on Purkinje cell growth and maturation. Although the basic layering of the cerebellar cortex was not altered, alignment of Purkinje neurons to form a monocellular layer was delayed associated with disorientation of some neurons in the ethanol-exposed pups. Delayed differentiation of Purkinje neurons in the experimental animals was also noted as evidenced by the ribosomal accumulation at the basal aspect of the cell at 14 days postnatally, resembling a 7-day control pup. Purkinje neurons of control pups were well differentiated at 14 21 days, with a centralized nucleus surrounded by a cytoplasm containing Nissl bodies, numerous Golgi complexes, and mitochondria. The ethanol-exposed pups at 14 21 days showed delayed maturation indicated by a basal ribosomal mass, with few segments of rough endoplasmic reticulum. At 28 42 days the Purkinje neurons of the controls showed a greater degree of differentiation and maturation in contrast to the reduced protein-synthesizing machinery, i.e., poorly developed endoplasmic reticulum and Nissl bodies, in the experimental pups. These studies showed delayed differentiation and maturation of Purkinje neurons as a consequence of ethanol exposure.

Oogenesls in the terrestrial hermit crab, coenobita clypeatus (decapoda, anomura): II. Vitellogenesis.

Oocytes from the land hermit crab, Coenobita clypeatus, in various stages of vitellogenesis were examined by light and electron microscopy. Early vitellogenic oocytes are characterized by accumulations of discrete vesicles of endoplasmic reticulum in the perinuclear cytoplasm. As oocytes develop, the endoplasmic reticulum becomes abundant, and numerous Golgi complexes are seen. There is a well developed Golgi-endoplasmic reticulum interaction. Within the confines of the reticulum are discrete intracisternal granules, which can be seen coalescing into electron-dense yolk bodies. Lipid accumulation is seen throughout the cytoplasm. Coincident with the burst of intra-oocytic metabolism are oolemma modifications and micropinocytosis, which provide ultrastructural evidence for extra-oocytic yolk production. The mature oocyte contains numerous yolk and lipid vesicles of varying electron density that comprise both intra- and extra-oocytic substrates.

The formation of glandular secretion in larval Austramphilina elongata (Amphilinidea)

The ultrastructure of three types of gland cells of embryos and free-swimming larvae of Austramphilina elongata is described. Type I gland cells contain large, more or less round electron-dense granules which are formed by numerous Golgi complexes. Type II gland cells contain thread-like, membrane-bound secretory granules with longitudinally arranged microtubules inside the granules; secretory droplets are produced by Golgi complexes and the microtubules apparently condense in the cytoplasm or in the droplets. Type III gland cells contain irregular-ovoid membrane-bound granules with coiled up microtubules which have an electron-dense core; the granules are formed by secretionderived from Golgi complexes and the microtubules aggregate around and migrate into the secretion; microtubules are at first hollow and the early secretory granules have a central electron-dense region.

Mast cell "disappearance" in chronic murine graft-vs-host disease (GVHD)-ultrastructural demonstration of "phantom mast cells".

Mast cells were studied during the induction of chronic graft-vs-host disease (GVHD) induced in mice across minor histocompatibility barriers. B10.D2 spleen cells (or control BALB/c cells) were injected into irradiated (600 rad) BALB/c recipients. Serial skin biopsies were taken over 26 days, during which time changes occurred resembling scleroderma, namely, dermal fibrosis, a mononuclear cell infiltrate, and loss of fat and appendages. Mast cells, when stained with toluidine blue, "disappeared" from GVHD, but not from control skin. Ultrastructural analysis showed that mast cells in GVHD skin were indeed present but underwent degranulation. Some mast cells showed only pale expanded sacs, indicating granule depletion. Because these cells could not be seen by toluidine blue staining but were plainly present, we have called them "phantom mast cells." Cellular activation occurred in many GVHD mast cells as shown by increased cytoplasmic activity, with numerous Golgi complexes, ribosomes, granular endoplasmic reticulum, and small vesicles. No identifiable mast cells were seen after day 19. No significant changes were seen in the mast cells of syngeneic control mice. We believe that immunologic processes in chronic GVHD cause a slow release of mast cell granule contents, which is different from anaphylactic degranulation. The depleted mast cells (invisible by toluidine blue staining) are also activated, perhaps in an attempt to replete their stores of granule contents. We discuss the relation of mast cell changes to fibrosis.

Is the nuclear envelope a 'generator' of membrane? Developmental sequences in cytomembrane elaboration.

Early diplotene oocytes from Necturus maculosus ranging from approximately 0.2 to 0.5 mm in diameter were examined by electron microscopy. In the smallest oocytes of this range, the cytoplasm is largely devoid of membranes, but contains primarily ribosomes and mitochondria. In slightly larger oocytes, smooth-surfaced cytomembranes first appear in the perinuclear cytoplasm. At this time, the outer layer of the germinal vesicle nuclear envelope (GVNE) shows frequent connections with long membranous lamellae that extend for considerable, but variable distances into the juxtanuclear ooplasm. The number of smooth membranous lamellae increases tremendously as the oocytes increase in diameter. In such oocytes as well, frequent continuities are observed between the outer membrane of the GVNE and many of the cytoplasmic membranes. Eventually, as the ooplasm becomes populated with extensive numbers of membranous lamellae, instances of continuity between the membranous lamellae and nuclear envelope now become sparse and eventually non-existent. The frequent connections observed between membranous lamellae and the outer membrane of the GVNE during a circumscribed interval of diplotene strongly implicate the GVNE in the generation of extensive amounts of cytoplasmic membrane. The ooplasm of larger oocytes in the size range indicated contain numerous Golgi complexes and large quantities of annulate lamellae most of which are positioned in the peripheral or subcortical ooplasm, as well as extensive quantities of smooth membranes of the endoplasmic reticulum and lipid droplets.

The formation of the pronuclei and their associated perinuclear cytoplasm; the determination of the phases of the first cleavage cycles inCrepidula fornicata(Mollusca, Gastropoda)

Summary The behaviour of the male and the female pronuclei in Crepidula fornicata is studied, beginning at the formation of the second polar body. Shortly after the extrusion of the second polar body the female pronucleus is formed, and then the male pronucleus enters the yolk-free cytoplasm near the animal pole. Both pronuclei are enveloped by a typical nuclear membrane, and increase in size until the prophase; a zygote nucleus is not formed (“Ascaris type” of fertilization). In the meantime, the chromatin of both pronuclei is arranged in a meshwork in the centre of the pronuclei. Shortly after the formation of the second polar body a special cytoplasm, the “perinuclear cytoplasm”, is formed in the vicinity of each of the pronuclei. During the early stages of the first cleavage cycle this cytoplasm is composed of numerous Golgi complexes, small dense Golgi vesicles, smooth endoplasmic reticulum vesicles, mitochondria and rosettes of glycogen-like granules. At later stages, when the pronuclei have met and their plasms coalesced, the number of Golgi elements decreases; at the same time, the small dense Golgi vesicles increase in number and aggregate in clusters. The phases of the first three cleavage cycles are determined by cytophotometry. The nuclear DNA of the male pronucleus and that in the nuclei of the blastomeres of the 2- and the 4-cell stage is reduplicated between 7 and 33% of the normalized cleavage cycles; the G2-phase is between 33 and 57%, while the mitotic phase occupies the last part of each cleavage cycle and the first 7% of the next cleavage cycle. There is no G j-phase. Since the female pronucleus lies just beneath the polar bodies, its DNA content could not be measured separately.

The ultrastructure of oogenesis inCulex theileri

The 12-36 h post blood meal (PBM) oocyte in C. theileri is characterized by a dramatic increase in the quantity of protein with concomitant changes in the adjacent follicular epithelium. The cytoplasm shows a preponderance of mitochondria and rough endoplasmic reticulum in proportion to free ribosomes. Numerous Golgi complexes, which bud off secretory granules, are also found scattered in the cytoplasm. These changes are concerned with the deposition of the vitelline membrane and by 36 h PBM, a continuous vitelline membrane is formed at the follicle cell-oocyte interface. Vitellogenesis appears to be completed by 48 h PBM and the final maturation stages are concerned solely with deposition of the chorionic membrane. In C. theileri the chorionic membrane seems to be synthesized in a similar manner to the vitelline membrane; namely from the aggregation of secretory droplets and only proceeds once the vitelline membrane formation is completed. The chorionic membrane is made up of an endochorion and an exochorion. Although the structural complexity of the follicular epithelium is maintained at 48 h PBM, its appearance at 60 h PBM is indicative of degenerative changes. By 60 h PBM synthesis of both the vitelline and chorionic membranes has been completed and vitellogenesis has ceased. This stage then represents the complete maturation of the ovum in C. theileri.

Ultrastructure of Brachycoelium salamandrae Gastrodermis with Observations on the Effects of Starvation

The fine structure of the digestive tract of the digenetic trematode Brachycoelium salamandrae was studied. The digestive tract consisted of a foregut region whose lining was cytoarchitecturally similar to the general body tegument. Glands opened into the lumen of the foregut via microtubular-supported ducts. The junction between the foregut and the cellular gastrodermis was marked by a prominent desmosome. The apical plasma membranes of the gastrodermal cells were amplified by means of lamellae. The cells display an extensive rough endoplasmic reticulum, mitochondria, and numerous Golgi complexes. Two types of vesicles were observed. One type was a vesicle with a homogeneous matrix that appeared to be associated with the emitting face of Golgi complexes. Another structure was the multivesicular body that displayed acid phosphatase activity. This latter organelle was observed at times to be associated with autophagic vacuoles and is believed to be a part of the lysosome system of the gastrodermis. Starvation of the worms resulted in an increase in the disintegration of gastrodermal cells as well as an increase in the number of autophagic vacuoles in the cytoplasm. Ultrastructural organization of the adult diges- tive tract representative of nine families and 22 species of digenetic trematodes has been described to date (Fujino and Ishii, 1979). A number of cytochemical studies have supplemented the morphological studies and have provided invaluable information pertaining to the func- tion of portions of the digestive tracts of these organisms (see Erasmus, 1977, for a review). The objective of the present investigation was to study the ultrastructure of the digestive tract of Brachycoelium salamandrae, a trematode family whose ultrastructure has hitherto not been described. Preliminary cytochemical studies were made in order to compare distribution of acid phosphatase activity in both normal and starved worms. This aspect of the study was designed to provide greater understanding of the function of certain organelles associated with the digestive tract as well as provide a base for comparison of the distribution of the enzyme in B. salamandrae with that found in other digenea.

Ultrastructure of the ovary and oogenesis in the polychaete Capitella jonesi (Hartman, 1959).

Ultrastructural features of the ovary and oogenesis in the polychaete Capitella jonesi (Hartman, '59) have been described. The ovaries are paired, sac-like follicles suspended by mesenteries in the ventral coelom throughout the midbody region of the mature worm. Oogenesis is unsynchronized and occurs entirely within the ovary, where developing gametogenic stages are segregated spatially within a germinal and a growth zone. Multiplication of oogonia and differentiation of oocytes into the late stages of vitellogenesis occur in the germinal region of the ovary, whereas late-stage vitellogenic oocytes and mature eggs are located in a growth zone. Follicle cells envelop the oocytes in the germinal zone of the ovary and undergo hypertrophy and ultrastructural changes that correlate with the onset of vitellogenesis. These changes include the development of extensive arrays of rough ER and numerous Golgi complexes, formation of microvilli along the surface of the ovary, and the initiation of extensive endocytotic activity. Oocytes undergo similar, concomitant changes such as the differentiation of surface microvilli, the formation of abundant endocytotic pits and vesicles along the oolemma, and the appearance of numerous Golgi complexes, cisternae of rough ER, and yolk bodies. Yolk synthesis appears to occur by both autosynthetic and heterosynthetic processes involving the conjoined efforts of the Golgi complex and rough ER of the oocyte and the probable addition of extraovarian (heterosynthetic) yolk precursors. Evidence is presented that implicates the follicle cells in the synthesis of yolk precursors for transport to the oocytes. At ovulation, mature oocytes are released from the overy after the overlying follicle cells apparently withdraw. Bundles of microfilaments within the follicle cells may play a role in this withdrawal process.

Age changes in the fine structure of rat trophoblast giant-cells.

The fine structure of trophoblast giant-cells from the junctional zone of rat placentas was examined at intervals during two periods, namely, from 12 days of pregnancy (by which time the chorioallantoic placenta has differentiated into junctional zone and labyrinthine regions) until 21 days, and from term (at 23 days) until 4 days beyond term in living conceptuses experimentally restrained in utero beyond littermate delivery. Giant cells appeared viable throughout both periods in that they possessed numerous Golgi complexes, abundant free polyribosomes and mitochondria, and an euchromatic nucleus which was delimited by a nuclear envelop with prevalent nuclear pores. In that many free polyribosomes and few cisterns of endoplasmic reticulum were present giant cells had an undifferentiated appearance at 12 days; they appeared actively phagocytotic through day 18. Both forms of the reticulum were present, but variably so, throughout both periods that were examined; neither was markedly abundant at any stage. Correlation has been sought between the prevelence of agranular and granular cisterns of the reticulum and the relative amounts of secretion, respectively, of placental somatomammotropin and steroid. There was some correlation between development of granular reticulum and known somatomammotropic production, but none between agranular reticulum and what is known about placental progresterone levels during pregnancy in rats. A lack of an elaborately developed agranular endoplasmic reticulum in these giant elements suggests that the cholesterol necessary for progesterone synthesis is itself synthesized elsewhere.

SPERMATOGENESIS IN A TRICHUROID NEMATODE,TRICHURIS MURIS.II. FINE STRUCTURE OF PRIMARY SPERMATOCYTE AND FIRST MEIOTIC DIVISION

Ultrastructural observations indicate that the primary spermatocyte of Trichuris muris is larger than the spermatogonial stage with an increased cytoplasm to nucleus ratio. The cytoplasm contains an extensive reticular system, mitochondria, numerous free ribosomes and prominent Golgi complexes which may contribute to the formation of a sub-surface, vesicular complex. Although only two spermatocytes were seen to be linked by a cytoplasmic bridge it is suggested that the number of conjoined cells is probably greater. The rearrangement of mitochondria in a ring around the nucleus and the indentation and vesiculation of the nuclear envelope preceeded its disappearance and indicated the onset of meiosis. Centrioles were frequently resolved at this stage. They were composed of nine peripheral doublets surrounded by a dense pericentriolar sheath. Three dense chromatin areas indicative of haploid chromosomes were present in later meiotic stages. Each chromosome was surrounded by a number of mitochondria and there...

Human diploid fibroblast-like cells (CF-3) as a model system for the study of Golgi biogenesis.

Human diploid fibroblast-like cells were maintained in an arrested, essentially non-mitotic state for extended periods of time in culture by lowering the serum concentration in the medium from 10 to 0.5%. These arrested cells re-entered the proliferative state when subcultivated in medium containing 10% serum. The morphological distribution and enzyme activities associated with the Golgi complex were examined during growth, arrest, and recovery. Cells grown in medium containing 10% serum possessed a well-developed Golgi complex consisting of parallel arrays of membranes and associated vesicles. Galactosyl transferase activity was highest after 3 days growth (17.5 +/- 5.0 nmol galactose transferred/45 min/mg protein) and declined to 9.8 +/- 3.0 at day 7. When the serum concentration was reduced to 0.5%, Golgi complexes were rarely observed by electron microscopy and galactosyl transferase activity was further reduced into medium containing 10% serum recovered from the arrested state and ultrastructurally resembled cells continuously cultured at the higher serum level. Numerous Golgi complexes reappeared and galactosyl transferase activity increased to 13.0 +/- 3.34 days after subcultivation. These results indicate that the Golgi complex can be experimentally manipulated in human diploid fibroblast-like cells in a manner which may be useful for the study of the biogenesis of this organelle.