In vitro culture of rediae of Echinostoma caproni.

Rediae of Echinostoma caproni (Egyptian strain) were dissected from Biomphalaria glabrata snails at intervals from 13-34 days post-exposure and co-cultured for up to 51 days with cells of the B. glabrata embryonic (Bge) cell line. Rediae readily ingested Bge cells and survived longer when co-cultured with cells than in cell-free cultures. Rediae released mostly motile cercariae throughout the observation period when in Bge medium and cells. Rediae cultured in 199 medium with Bge cells also produced progeny throughout most of the observation period. In the latter medium, progeny were much more likely to include rediae as well as cercariae. Some cercariae produced in vitro encysted as metacercariae. Rediae consumed cercariae released into culture but were not observed to attack one another or rediae of a different echinostome species.     

Histopathology, ultrastructure and immunohistochemistry of Coregonus lavaretus hearts naturally infected with Ichthyocotylurus erraticus (Trematoda)

Histopathological, ultrastructural and immunohistochemical investigations were conducted on 26 specimens of powan Coregonus lavaretus (L.) from Loch Lomond (Scotland). The hearts of all 26 powan (15 females and 11 males) investigated harboured metacercariae of the digenean trematode Ichthyocotylurus erraticus (Rudolphi, 1809). The vast majority of metacercariae were located either singly or as an aggregation of white cysts on the surface of the bulbus arteriosus. The intensity of infection ranged from 2 to 200 larvae heart(-1), although the number of metacercariae found on male powan did not exceed 13. Histochemically, the parasite cyst wall gave a strong positive reaction with periodic acid schiff (PAS) and a faint positive signal with Azan-Mallory stain. All the metacercariae cysts were embedded in a granulomatous proliferation of heart epicardium tissue, forming a reactive fibroconnective capsule around the parasite. The capsule enclosing the parasite (produced by the host's reaction to the parasite) measured 13.57 to 90.20 microm (37.43 +/- 3.56) in thickness. Within the capsule wall, eosinophilic granular cells (EGCs), granulocytes, melanocytes and, in some instances, partially degenerated or vacuolated epithelioid cells were observed in close proximity to the cyst wall. Pigment-bearing macrophages were scattered throughout the granulomatous host-tissue reaction and as macrophage aggregates (MAs) within the capsules surrounding parasites. Immunohistochemical tests were applied to infected heart sections using 12 different antisera. Nerve fibres immunoreactive to bombesin, substance P (SP), and atrial natriuretic peptide (ANP) antisera were observed in close proximity to the parasite larvae. The presence of a serotonin-like substance was also observed within host immune-cells surrounding trematode cysts. Large cells of the epicardium were found to be immunoreactive to met-enkephalin and vasoactive intestinal peptide (VIP) antisera but not immunoreactive to anti-protein gene-product 9.5 (PGP9.5) sera.     

EXOCYTOSIS OF LATEX BEADS DURING THE ENCYSTMENT OF ACANTHAMOEBA

Cells of Acanthamoeba castellanii (Neff) are known to form mature cysts characterized by a cellulose-containing cell wall when transferred to a nonnutrient medium. Amebas which engulfed latex beads before encystment formed mature cysts essentially devoid of bead material. The encystment of bead-containing cells appeared to be similar to that of control cells since no important differences between the two were observed with respect to cellular levels of glycogen or protein, cellulose synthetase activity, the amount of cyst wall polysaccharide formed, or the percentage of cysts formed. Actinomycin D and cycloheximide inhibited encystment as well as bead expulsion. Ultrastructural analysis revealed that the beads, which initially were contained in phagocytic vesicles, were released from the cell by fusion of vesicular membranes with the plasma membrane. Exocytosis was observed in cells after 3 hr of encystment, with most of the beads being lost before cyst wall formation. Each bead-containing vesicle involved in expulsion was conspicuously demarcated by an area of concentrated cytoplasm, which was more homogeneously granular than the surrounding cytoplasm. Beads were not observed in the cytoplasm of mature cysts but were occasionally found in the cyst wall.     

The outer cyst wall ofBdellovibrio bdellocysts is made de novo and not from preformed units from the prey wall

Bdellovibrio sp. strain W bdellocysts were produced inEscherichia coli using three sources of³H-diaminopimelic acid (DAP) for incorporation into the cyst wall peptidoglycan: (a) labeledE. coli peptidoglycan, (b) labeledBdellovibrio peptidoglycan, and (c) exogenous³H-DAP in the encystment medium. After cysts were produced, they were either sonicated to remove the prey cell wall, or germinated to solubilize the cyst wall. The results show that label was incorporated into the cyst wall preferentially from the exogenous DAP in the medium, and not from the bdellovibrio or bdelloplast peptidoglycan. The encysting bdellovibrio does not therefore incorporate existing peptidoglycan units from the bdelloplast for synthesis of the cyst wall.     

Axenic culture of Schistosoma mansoni sporocysts in low O2 environments.

Recent successes in culturing intramolluscan larval stages of Schistosoma mansoni have relied on synxenic culture with a cell line (Bge) developed from embryos of a molluscan host Biomphalaria glabrata. To further facilitate progress toward control of schistosomiasis, a system for axenic in vitro culture of the parasite has now been developed. When culture media were preconditioned by Bge cells, sporocysts lived longer in vitro and produced more offspring. Because Bge-derived components could be protecting sporocysts from oxidative stress, axenic sporocysts were cultured at lowered O2 levels. In an hypoxic environment, S. mansoni sporocysts grew well and produced daughter sporocysts continuously under axenic conditions and in a medium completely lacking host molecules. Sporocyst production occurs independently of host influence.     

Plasmatocytes from the moth Pseudoplusia includens induce apoptosis of granular cells

The primary immune response toward internal parasites and other large foreign objects that enter the insect hemocoel is encapsulation. Prior studies indicated that granular cells and plasmatocytes are the two hemocyte types required for capsule formation by the moth Pseudoplusia includens (Lepidoptera: Noctuidae). Capsules formed by P. includens also have a defined architecture with primarily granular cells attaching directly to the target, multiple layers of plasmatocytes adhering to this inner layer of granular cells, and a monolayer of granular cells attaching to the capsule periphery. Dye-exclusion assays indicated that granular cells die shortly after attaching to the capsule periphery, leaving a basal lamina-like layer around the capsule. In examining the mechanisms underlying granular cell death, we found that culture medium preconditioned by plasmatocytes induced apoptosis of granular cells. Characteristics of plasmatocyte-induced apoptosis included condensation of chromatin, cell surface blebbing and fragmentation of nuclear DNA. Plasmatocyte-conditioned medium did not induce apoptosis of other hemocyte types, and medium conditioned by other hemocyte types did not induce apoptosis of granular cells. The adhesive state of granular cells and plasmatocytes also affected levels of apoptosis. Conditioned medium from spread plasmatocytes induced higher levels of granular cell apoptosis than medium conditioned by unspread plasmatocytes. Reciprocally, spread granular cells underwent significantly higher rates of apoptosis than unspread granular cells in medium conditioned by spread plasmatocytes. In situ analysis indicated that granular cells on the periphery of capsules also undergo apoptosis. Collectively, our results suggest that spread plasmatocytes release one or more factors that induce apoptosis of granular cells, and that this response is important in the final phases of capsule formation.     

Immunohistological localisation of two hydatid antigens (antigen 5 and antigen b) in the cyst wall, brood capsules and protoscoleces of Echinococcus granulosus (ovine and equine) and E. multilocularis using immunoperoxidase methods.

Cyst wall, brood capsules and evaginated protoscoleces of E. granulosus (ovine and equine) and E. multilocularis were fixed in 10% formol-saline, embedded in paraffin and cut at 8 micrometer. Specific rabbit antisera to antigen 5 and antigen B of hydatid cyst fluid were used with immunoperoxidase methods to localise the antigens in the histological sections. Antigen 5 was found in all parasites and was associated with cells of the subtegumental area of the protoscolex, the brood capsule wall and the germinal membrane. The labelled antigen appeared as distinct granules in all areas. It is suggested that antigen 5 may be synthesised in all of these sites and that a source of the antigen in cyst fluid may be the germinal and brood capsule membranes. The laminated membranes of E. granulosus (ovine and equine) were, except for the superficial layers, free from antigen 5. Antigen B was present in all parasites. It was distributed diffusely throughout the laminated membrane, germinal membrane and brood capsule wall. There were areas of densely labelled antigen B on the surface of the distal cytoplasm of the protoscolex tegument and the surface of calcareous corpuscles. The distribution of antigen B in relation to PAS positive material and possible complement activating substances is discussed. The laminated membrane of E. granulosus was apparently more permeable to antigen B than to antigen 5. It is suggested that differences in the diffusion of these antigens through the laminated membranes of hydatid cysts in the same or different host species may account for variable serological responses during infection.     

Bovine joint capsule and fibroblasts derived from joint capsule express aggrecanase activity.

Bovine joint capsule was maintained in explant culture in the presence of bovine aggrecan monomer and it was shown that the aggrecan monomer was degraded. Amino-terminal sequence analysis of the resulting aggrecan core protein fragments revealed that the core protein was cleaved at five specific sites attributed to glutamyl endopeptidases referred to as aggrecanase activity. Fibroblast cultures were established from explant cultures of joint capsule and when these cells were exposed to aggrecan, cleavage of the core protein of aggrecan at the aggrecanase sites was observed. Inclusion of either retinoic acid or interleukin-1alpha in medium of either joint capsule explant cultures or fibroblast cultures did not increase the rate of cleavage of exogenous aggrecan present in the culture medium. When aggrecan monomer was incubated with conditioned medium from explant cultures of joint capsule maintained in medium, degradation could be detected after 10 min. After a 6-h incubation period the same fragments of aggrecan core protein were observed as those for tissue or cells incubated directly with aggrecan monomer. RT-PCR analysis of mRNA extracted from joint capsule fibroblasts showed that these cells express both aggrecanase-1 and -2 [ADAMTS-2 (Tang) and ADAMTS-5].     

Turnover of proteoglycans by chick lens epithelial cells in cell culture and intact lens

Chick lens epithelial cells were cultured on plastic and type IV collagen substrata, and the confluent cultures were labeled continuously with [35S]sulfate for 20 h. Intact lenses were also labeled in the same way. 35S-Proteoglycans isolated from those cultures were compared for their molecular sizes and glycosaminoglycan compositions. The results have shown that: 1) Proteoglycans synthesized by cells on type IV collagen were significantly smaller than those by cells on plastic. 2) Proteoglycans of intact lens showed a broad distribution of molecular size and contained a high proportion of chondroitin sulfate in the medium fraction compared to those of the two cell cultures. In order to explain such differences between proteoglycans from cultures, label-chase experiments with [35S]sulfate were done for proteoglycans synthesized. 35S-Proteoglycans isolated at each chase time 0, 2.5, and 17 h) were compared and the following results were found: 1) The cell layers of both "plastic" and "type IV collagen" cultures contained glycosaminoglycan species predominantly at each chase time rather than proteoglycans. 2) Changes in the glycosaminoglycan compositions of medium fractions of cell cultures were observed during the chase period; in medium of the "plastic" culture, proteoheparan sulfate increased with chase time, whereas in medium of the "type IV collagen" culture, chondroitin sulfate glycosaminoglycan (not proteoglycan) increased with chase time. 3) In intact lens culture, lens capsule fraction at every chase time contained a proteoglycan unique in molecular size, which was not found in cell culture fractions. 4) All fractions from intact lens cultures contained a higher content of chondroitin sulfate at every chase time than the respective fractions from cell cultures. These results suggest that adhesion of the cells to type IV collagen or lens capsule influences the degradation and secretion of proteoglycans. In addition, they can account partially for the above-described differences in molecular sizes and glycosaminoglycan compositions between 35S-proteoglycans from various cultures continuously labeled with [35S]sulfate.     

Cyst formation in a freshwater strain of the choanoflagellate Desmarella moniliformis Kent

Cyst formation in a freshwater strain of the colonial freshwater choanoflagellate Desmarella moniliformis Kent (Protozoa: Choanoflagellida) has been studied with light and electron microscopy for the first time. Batch cultures inoculated with motile vegetative cells start to produce cysts within 3 days during the exponential phase of growth. Cyst production proceeds until in late stationary phase there is a preponderance of cysts. Transfer of cysts to fresh medium results in limited excystment. Encystment involves the production of electron-dense fibrillar wall material, firstly around the neck of the cell and then around the posterior end. As the wall material is deposited the neck of the cell elongates and the dictyosome rotates from the horizontal to vertical plane. The number of mitochondrial profiles seen in individual sections of cells increases. Finally the neck of the cell is retracted, the flagellum and collar tentacles are withdrawn, and the bottom of the neck of the cyst wall is sealed with a diaphragm of wall material. Excystment, which has not been observed directly, appears to involve the disruption of the wall at the base of the neck, the remainder of the cyst wall remains intact. Comparisons are made between encystment in Desmarella and cyst development in other protists.     

Similarity in cyst wall protein (CWP) trafficking between encysting Giardia duodenalis trophozoites and CWP-expressing human embryonic kidney-293 cells

Cyst wall proteins 1 and 2 (CWP1 and CWP2) are major constituents of the giardial cyst wall and are expressed with similar kinetics by encysting trophozoites. In the present study, we were interested to determine if the expression of giardial CWPs as heterologous proteins in a higher eukaryotic cell would result in their trafficking across the secretory pathway, as is the case in encysting trophozoites. Recombinant (r)CWP1 and rPro-CWP2 were detected in the lysate and culture media of transfected HEK-293 cells. We then conducted intracellular localization experiments using confocal microscopy and found that the proteins were trafficked in membrane enclosed vesicles across the secretory pathway and released to the culture medium by transfected HEK-293 cells. We then dissected the rCWP1 and rPro-CWP2 molecules to identify the portion(s) responsible for their secretion and found that the putative N-terminal signal peptide was sufficient for directing the secretion of rCWP1, while both the putative N-terminal signal peptide and the 13kDa C-terminal regions were necessary for the secretion of rPro-CWP2 by transfected HEK-293 cells. Taken together, these results demonstrate the degree of conservation of signal peptide recognition between lower and higher eukaryotes.     

Cell Wall Turnover at the Hemispherical Caps of Bacillus subtilis

Cell walls made by Bacillus subtilis bacteria grown in D(2)O medium have buoyant densities in CsCl which are different from walls made by cells grown in H(2)O medium. Cell wall turnover was studied by measuring the change in wall buoyant density after a B. subtilis culture was shifted from growth in D(2)O medium to aeration in H(2)O medium. Walls from the hemispherical caps were isolated after preferential digestion of wall from the cylindrical regions using the B. subtilis autolytic amidase. The walls from the polar regions were found to turn over extensively.     

Adenylate cyclase activity during growth and encystment of Acanthamoeba castellanii

The adenylate cyclase activity of Acanthamoeba castellanii (Neff) was studied in extracts prepared after breaking cells in the Potter-Elvehjem homogenizer. The adenylate cyclase activity of cells is low during the exponential growth phase, but then rises 2–4-fold during the stationary phase to a peak, roughly at the time that cyst forms are detectable in the culture. A 2–4-fold activity rise to a peak also occurs 4–8 h after late log cells are transferred to a non-nutrient encystment medium, a time which is shortly before numbers of cyst forms can be detected in the culture. The pattern of activity observed when stationary phase cells are transferred to encystment medium is complex and depends in part on whether the cultures have exhibited the peak of cyclase activity and have begun to initiate cyst formation prior to the transfer. Within the usual time frame after transfer to encystment medium, early logarithmic phase cells do not exhibit a 2–4-fold rise of cyclase activity and they do not encyst. The results suggest a relationship between encystment and the pattern of rise and fall in cyclase specific activity. Fractionation of the homogenate of trophozoites indicated that adenylate cyclase activity was associated with the particulate microsomal fraction.     

Induction of wall ingrowths of transfer cells occurs rapidly and depends upon gene expression in cotyledons of developing Vicia faba seeds

Summary. Abaxial epidermal cells of developing faba bean (Vicia faba) cotyledons are modified to a transfer cell morphology and function. In contrast, the adaxial epidermal cells do not form transfer cells but can be induced to do so when excised cotyledons are cultured on an agar medium. The first fenestrated layer of wall ingrowths is apparent within 24 h of cotyledon exposure to culture medium. The time course of wall ingrowth formation was examined further. By 2 h following cotyledon excision, a 350 nm thick wall was deposited evenly over the outer periclinal walls of adaxial epidermal cells and densities of cytoplasmic vesicles increased. After 3 h in culture, 10% of epidermal cells contained small projections of wall material on their outer periclinal walls. Thereafter, this percentage rose sharply and reached a maximum of 90% by 15 h. Continuous culture of cotyledons on a medium containing 6-methyl purine (an inhibitor of RNA synthesis) completely blocked wall ingrowth formation. In contrast, if exposure to 6-methyl purine was delayed for 1 h at the start of the culture period, the adaxial epidermal cells were found to contain small wall ingrowths. Treating cotyledons for 1 h with 6-methyl purine at 15 h following cotyledon excision halted further wall ingrowth development. We conclude that transfer cell induction is rapid and that signalling and early events leading to wall ingrowth formation depend upon gene expression. In addition, these gene products have a high turnover rate. Correspondence and reprints: School of Environmental and Life Sciences, Biology Building, University of Newcastle, Callaghan, NSW 2308, Australia.     

Ultrastructural immunocytochemical localization of two hydatid fluid antigens (antigen 5 and antigen B) in the brood capsules and protoscoleces of ovine and equine Echinococcus granulosus and E. multilocularis.

The unlabelled antibody method was used in the ultrastructural localization of two hydatid fluid antigens, antigen 5 and antigen B, in brood capsules and protoscoleces of Echinococcus granulosus and E. multilocularis. Antigen 5 was found in the parenchyma cells of the protoscolex and brood capsule wall and to a lesser extent in the walls of the flame cells and collecting ducts of the excretory system and in the surrounding interstitial material. It is suggested that, while some excretion of this antigen may occur from the protoscolex, it could also be liberated into the cystic cavity by degeneration of protoscoleces and parenchymal cells of the brood capsule wall. Antigen B was found mainly in the distal cytoplasm and perinuclear cytoplasm of the tegument anterior to the suckers. It is apparently secreted to the outside and was present in the brood capsule contents; it adheres to the anterior surface and the posterior periodic acid-Schiff (PAS)-positive glycocalyx of the protoscolex and to the inner surface of the brood capsule wall. The protoscolex tegument posterior to the suckers was negative. The parenchyma cells of the protoscolex and brood capsule wall were also positive although the intensity of the reaction product was variable.     

Synthesis and secretion of bacterial alpha-amylase by the yeast Saccharomyces cerevisiae

Alpha-amylase from Bacillus amyloliquefaciens, synthesized in yeast Saccharomyces cerevisiae without substitution of the signal sequence, is efficiently secreted from yeast cells: 60-70% of the overall amount of the enzyme is found in the culture fluid. In contrast to many yeast secretory proteins, which accumulate in the periplasmic space and in the cell wall, intracellular alpha-amylase is localized mainly in the cytoplasm. Obviously, transfer across the cell wall is not a rate-limiting step in alpha-amylase export from the cell. The glycosylated forms of proteins are predominantly found both inside the cell and in the culture medium.     

A light and electron microscopic study of tissue interactions between a parasitic copepod, Scolecodes huntsmani (Henderson), and its host ascidian, Styela gibbsii (Stimpson)

The structure of the cellular cyst which encapsulates the parasitic copepod, Scolecodes huntsmani, in the subendostylar blood vessel of the ascidian, Styela gibbsii, is described from light and electron microscopic studies. The cells comprising the cyst are contributed by the ascidian. The cells are columnar, contain large central reservoirs of glycogen and lipid, and have a conspicuous Golgi apparatus, many small cisternae of smooth endoplasmic reticulum and peripheral mitochondria. The cells are held together by complex basal interdigitations and a short apical zonula occludens. Long cilia emerge in circular clusters from the cell apices and beat in the lumen of the cyst. As atypical of a columnar epithelial layer, the nuclei are staggered in position in the cells and there is no basal lamina. One end of the cyst is blind, but the other end, which may be either anterior or posterior with respect to the longitudinal axis of the host, narrows to a profusely ciliated duct which opens through the wall of the blood vessel to the atrium of the ascidian by a ciliated funnel. The effective beat of the cilia of the duct and the funnel is outward toward the atrium. The first nauplii of the copepod emerge from the incubatory pouch of the adult and pass to the exterior sea water through the cyst funnel and the atrium and atrial siphon of the ascidian. As in other notodelphyid copepods, the life cycle of this incarcerated form also involves free-living naupliar stages followed by two free-living copepodid stages. The provision of an egress for the first nauplii is, therefore, important to the survival of the species. The adult females of Scolecodes, which range in length from 2 to 14.6 mm, are sluggish when removed from the cyst and fail to survive in sea water for more than 24 hours. The males, which have only been obtained when parasitic fifth copepodids molt in culture, are much smaller, averaging 0.8 mm, and are very active. Since one dead male has been found inside the cyst of an adult female and females are often found with attached spermatophores, it is suggested that the funnel of the cyst may also serve as an entrance for the males. Evidence is presented for the formation of the cyst as an accumulation of totipotent lymphocytes around the copepod. Cysts of parasitic developmental stages (third through fifth copepodids) are also described. All of these cysts and those of immature adult females lack funnels to the atrium. The funnel of the cyst of mature females is formed, in part, by modified cells of the wall of the blood vessel, but is induced after the major portion of the cellular cyst has been formed. Cells in the general circulation of the ascidian and those inside the lumen of the cyst are compared. The cells in the lumen of the mature cyst do not arise by diapedesis of blood cells from the subendostylar blood vessel, but by conversion and migration of cells composing the cyst proper. These cells have been found in the guts of the copepods and they may serve as a nutritive source. The ascidian appears not to be harmed by the association, but the copepod gains in many ways.     

Export of an invertase by yeast Candida utilis cells

Export and accumulation of various forms of invertase (EC 3.2.1.26) in the cell wall and culture medium of the yeast Candida utilis was investigated. It was found that there is the high-molecular-weight invertase in the cell wall (CW-form). This form is not exported into the culture medium, and it is by a third more glycosylated than the previously described exported S-form. It was shown that one of the two forms of invertase exported into the culture medium—the glycosylated S-form—is retained in the cell wall, while the other one-the nonglycosylated F-form—was not detected in the cell wall. Based on these results, as well as data on the distribution dynamics of the enzyme in the culture medium and in the cell wall during different growth stages of a yeast culture, we suggested that the nonglycosylated form was exported into the culture medium via the zone of abnormal cell wall permeability and the glycosylated forms of this enzyme (both exported and nonexported) did not use this pathway and the degree of N-glycosylation is an important factor determining the final localization of the enzyme.     

Microencapsulation of human fibroblasts in a water-insoluble polyacrylate

Viable human diploid fibroblasts have been micro-encapsulated in EUDRAGIT RL, a commercially available water-insoluble polyacrylate, by an interfacial precipitation technique. Cells in medium and polymer solution (in diethyl phthalate) were coextruded and formed into droplets by a coaxial air stream. The droplets fell into a corn-oil/mineral-oil mixture to extract the solvent to precipitate the polymer around the cells. Capsules were ca. 500 mum in diameter depending on the air flowrate with a ca. 10-mum thick wall. When collagen (1 mg/mL) was added to the cell suspension prior to encapsulation and base-washed corn oil was used, cell growth occurred with one doubling achieved after five to six days as the collagen gel contracted inside the capsule. In the absence of collagen, cells spread on the inner wall of the capsule but did not grow, presumably because the surface charge on the capsule was inadequate. In similar fashion fibroblasts spread but did not grow on films of EUDRAGIT RL but did grow on blends of EUDRAGIT RL and EUDRAGIT E containing 10-30% of the latter more highly aminated polyacrylate. Although not suitable for anchorage-dependent cell growth by itself, EUDRAGIT RL has been suitable as a model polymer to demonstrate the feasibility of using water insoluble polyacrylates and organic solvents and nonsolvents for the micro-encapsulation of fibroblasts. Such microcapsules are of potential interest as a mode of large scale tissue culture for the production of novel therapeutic agents.     

Changes in wall-bound polysaccharidase activities during the culture cycle of a Rubus fruticosus cell suspension

Several hydrolytic enzyme activities were detected in the wall of developing cells of Rubus truticosus in suspension culture. The corresponding substrates of the enzymes are mostly polysaccharide wall constituents, except for chitinase activity. The activities measured when the enzymes were in the free state or wall-bound showed the positive influence of the cell wall micro-environment. Changes in the activities during a cell culture cycle demonstrated that those enzymes acting on xyloglucans behaved differently from the others, and suggest that xyloglucans undergo modifications in vivo over a longer period of time during the exponential growth phase. The same activities were identified in the culture medium. Endo-1,4-β-d-glucanase activities which depolymerized car☐ymethylcellulose (CMC) and xyloglucans (XG) were assayed viscosimetrically. It was found that XG oligosaccharides exhibited an inhibitory effect on the depolymerization of xyloglucans but not on that of CMC. This suggests that true xyloglucanases are present in the culture of Rubus cells.