Monoassociation with Lactobacillus acidophilus UFV-H2b20 stimulates the immune defense mechanisms of germfree mice

Probiotics are formulations containing live microorganisms or microbial stimulants that have some beneficial influence on the maintenance of a balanced intestinal microbiota and on the resistance to infections. The search for probiotics to be used in prevention or treatment of enteric infections, as an alternative to antibiotic therapy, has gained significant impulse in the last few years. Several studies have demonstrated the beneficial effects of lactic acid bacteria in controlling infection by intestinal pathogens and in boosting the host's nonspecific immune response. Here, we studied the use of Lactobacillus acidophilus UFV-H2b20, a lactic acid bacterium isolated from a human newborn from Vi?osa, Minas Gerais, Brazil, as a probiotic. A suspension containing 10(8) cells of Lactobacillus acidophilus UFV-H2b20 was inoculated into groups of at least five conventional and germfree Swiss mice to determine its capacity to stimulate the host mononuclear phagocytic activity. We demonstrate that this strain can survive the stressing conditions of the intestinal tract in vivo. Moreover, the monoassociation of germfree mice with this strain for seven days improved the host's macrophage phagocytic capacity, as demonstrated by the clearance of a Gram-negative bacterium inoculated intravenously. Monoassociated mice showed an undetectable number of circulating E. coli, while 0.1% of the original inoculum was still present in germfree animals. Mice treated with viable or heat-killed Lactobacillus acidophilus UFV-H2b20 presented similarly improved clearance capacity when compared with germfree controls. In addition, monoassociated mice had twice the amount of Kupffer cells, which are responsible for the clearance of circulating bacteria, compared to germfree controls. These results suggest that the L. acidophilus strain used here stimulates a nonspecific immune response and is a strong candidate to be used as a probiotic.     

Interleukin-9 is involved in host protective immunity to intestinal nematode infection

Murine studies have demonstrated that, as with other nematodes, infection with the intestinal nematode Trichinella spiralis is associated with a pronounced intestinal mastocytosis, eosinophilia and an elevation in serum levels of total IgE. Both interleukin (IL)-4 and IL-5 are clearly important in the generation of IgE responses and eosinophilia, respectively, but the control of mucosal mastocytosis in vivo is not as well defined. Mucosal mast cells appear to be particularly important with regard to T. spiralis infections as there is good evidence to suggest their involvement in expulsion of the parasite from the host. In this study we examined the effect of the overproduction of the Th2 cytokine IL-9 on infection with this nematode. We demonstrate that naive IL-9-transgenic mice have an intense intestinal mastocytosis and high serum levels of mouse mast cell protease-1. Moreover, upon infection high titers of parasite-specific IgG1 were observed with a heightened mast cell response, which was associated with the rapid expulsion of T. spiralis from the gut. Furthermore, as depression of this mast cell response, using anti-c-kit antibodies, resulted in the inability of these mice to expel the parasite, this study clearly demonstrates an activity of IL-9 on mucosal mastocytosis and the host protective immune response in vivo.     

Prognostic importance of gram-negative intestinal colonization preceding pancreatic infection in severe acute pancreatitis. Results of a controlled clinical trial of selective decontamination

OBJECTIVES: To establish, firstly, whether gram-negative (re)-colonization of the gut leads to an increased risk of gram-negative pancreatic infections and whether this event is time-related and, secondly, whether the difference in the quantity and quality of micro-organisms colonizing the digestive tract influences morbidity and mortality. DESIGN: Prospective analysis of the results of systematic semi-quantitative cultures of several body areas taken from patients with severe acute pancreatitis, during a controlled multicenter trial of adjuvant selective decontamination. SETTING: Surgical intensive care units of 16 hospitals. PATIENTS: A total of 2,159 semi-quantitative cultures from the oropharynx, rectum and pancreatic tissues taken from 90 patients were analyzed. Interventions: Surveillance cultures from the oropharynx and rectum were taken on admission and repeated twice weekly and from the (peri)-pancreatic devitalized tissues (i. e. necrosis) at every relaparotomy and from drainage. MEASUREMENTS AND RESULTS: All gram-negative pancreatic infections were preceded by intestinal colonization with the same micro-organisms. The risk of developing a pancreatic infection following gram-negative intestinal colonization (15/42 patients) was significantly higher as compared to patients without gram-negative colonization (0/10 patients) (p < 0.001) or to patients in whom E. coli was the only intestinal micro-organism cultured (0/30 patients) (p < 0.001). The occurrence of intestinal E. coli did not increase the risk of pancreatic infection. Gram-negative colonization of the rectum and oropharynx significantly correlated with the later development of pancreatic infection: relative risks 73.7 (p < 0.001) and 13.6 (p < 0.001), respectively. However, when both areas were evaluated simultaneously, the rectum was more significant (p < 0.001). The severity of intestinal intestinal colonization until the moment of pancreatic infection showed an increase in time in all 15 patients. In 11 of 15 patients (73%) these infections occurred within 1 week following the first isolation from the digestive tract. Gram-negative intestinal colonization was associated with a 3.7 fold increased mortality risk (p = 0.004). CONCLUSIONS: Gram-negative intestinal colonization, E. coli excepted, is an early prognostic parameter in patients in whom pancreatic infection has not yet occurred and represents a significantly increased risk of pancreatic infections and mortality.     

Generation and characterization of an IGFBP-7 antibody: identification of 31kD IGFBP-7 in human biological fluids and Hs578T human breast cancer conditioned media

The cDNA encoding mac25 (IGFBP-7) was firsr derived from mRNA isolated from leptomeningial and senescent human mammary epithelial cells (1,2). The open reading frame was shown to predict a protein with homology to the amino terminus of the IGF binding proteins, (IGFBP)1-6. Studies in our laboratory have shown that baculovirus generated mac25 binds IGF-I and-II in a specific manner, leading to the renaming of mac25 as IGFBP-7 (3). Further studies at the cellular level, to identify the involvement of IGFBP-7 in IGF regulation and cell growth, require a specific antibody against the protein, which has yet to be identified in either cultured cells or in vivo. We have now generated three polyclonal antibodies against the purified baculovirus peptide and, by western immunoblots and immunoprecipitation, demonstrated the existence of a specific 31,000 dalton protein. It is a secreted protein, and can be identified in the conditioned media of Hs578T breast cancer cells, as well as in normal human urine, cerebrospinal fluid and amniotic fluid. Subsequent studies with these antibodies should help elucidate the physiological role(s) of this protein.     

Administration of interleukin 13 to simian immunodeficiency virus-infected macaques: induction of intestinal epithelial atrophy

Increase Th2 cytokine production may contribute to some clinical manifestations of HIV infection, and studies have suggested that IL-13 rather than IL-4 is involved in these conditions. We directly tested this hypothesis by administrating IL-13 to SIV-infected macaques. SIV-infected rhesus macaques received a daily subcutaneous injection for 21 days of either IL-13 (10 microg/kg/day) or a placebo. The four macaques treated with IL-13 experienced body weight loss (9.95 +/- 0.71%) related to intestinal tract damage: they all suffered from a complete atrophy of duodenal villi. This was presumably due to premature epithelial cell death: proliferating Ki67+ cells in glandular crypts were as numerous as in control animals, but many epithelial cells developed apoptosis. The duodenal mucosa was infiltrated with cells expressing CD56 and PEN5, two markers of NK cells, and there was a deregulation of local cytokine and chemokine production characterized by a decrease in IL-10 gene expression (25% of controls) and an increase in gene expression for IFN-gamma (4-fold control), MIP-1alpha (8-fold control), and MIP-1beta (13-fold control). Thus, IL-13 can induce digestive epithelial cell injury in vivo in primates infected with a retrovirus. Therefore, its role should be considered in digestive manifestations of HIV infection as well as in other disorders associated with intestinal epithelial atrophy.     

Evaluation of Triage screening for drugs of abuse in postmortem blood and urine samples

BACKGROUND: Impaired changes in gastric epithelium proliferation have been described in Helicobacter pylori infection, and a progressive increase of proliferating cells has been shown with the progression of mucosal lesions. AIMS: Purpose of this investigation was to study the effect of eradication on bacterium-induced proliferative changes, evaluated by the proliferating cell nuclear antigen labelling index (PCNA LI) and its relationship to the ras oncoprotein p21, involved in early events of gastric carcinogenesis. PATIENTS AND METHODS: This retrospective study was performed, before and after therapy, in five different groups of patients with progressive stages of Helicobacter pylori damage (N: normality; HG: histological gastritis with normal endoscopy; EHG: histological gastritis with endoscopic chronic erosions; CIM: complete intestinal metaplasia; IIM: incomplete intestinal metaplasia). RESULTS: Six months after eradication, a normalization of PCNA LI was observed in the areas of gastritis, but not in those of intestinal metaplasia, which showed on unchanged type. Moreover, immunohistochemical membrane expression of ras oncoprotein p21 was only associated to intestinal metaplasia. The protein was also expressed in the cytoplasm in 3 patients with incomplete type. CONCLUSIONS: These results suggest that the development of intestinal metaplasia may be associated with an alteration in the control of gastric epithelium proliferation and could represent an initial stage in gastric carcinogenesis. Nevertheless, further genetic changes are necessary for a complete progression to neoplastic disease. A long-term follow-up on extension, type, proliferative situation and oncoprotein expression in areas of intestinal metaplasia may be helpful to explain whether the present data provide new information on the mechanism of Helicobacter pylori induced gastric carcinogenesis.     

Effectiveness of drug therapy alone or its combination with plasmapheresis in patients with severe angina pectoris

The influence of difuracil (PAP-49), a novel nitrofuran, on saprotrophic and normal digestive tract microflora was studied in vitro and in vivo by comparison with that of furazolidone. It was shown that the minimum inhibitory concentration of both the drugs ranged from 0.01 to 1.56 micrograms/ml. The experiments on rabbits with the use of the drugs in doses of 5 and 10 mg/ kg body weight revealed that unlike furazolidone difuracil induced no noticable qualitative or quantitative changes in the intestinal microflora composition.     

Persistent baculovirus infection results from deletion of the apoptotic suppressor gene p35

Infection with the wild-type baculovirus Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) results in complete death of Spodoptera frugiperda (Sf) cells. However, infection of Sf cells with AcMNPV carrying a mutation or deletion of the apoptotic suppressor gene p35 allowed the cloning of surviving Sf cells that harbored persistent viral genomes. Persistent infection established with the virus with p35 mutated or deleted was blocked by stable transfection of p35 in the host genome or by insertion of the inhibitor of apoptosis (iap) gene into the viral genome. These artificially established persistently virus-infected cells became resistant to subsequent viral challenge, and some of the cell lines carried large quantities of viral DNA capable of early gene expression. Continuous release of viral progenies was evident in some of the persistently virus-infected cells, and transfection of p35 further stimulated viral activation of the persistent cells, including the reactivation of viruses in those cell lines without original continuous virus release. These results have demonstrated the successful establishment of persistent baculovirus infections under laboratory conditions and that their establishment may provide a novel continuous, nonlytic baculovirus expression system in the future.     

Antibody response of children with enteropathogenic Escherichia coli infection to the bundle-forming pilus and locus of enterocyte effacement-encoded virulence determinants

Enteropathogenic Escherichia coli (EPEC) express a plasmid-encoded type IV pilus termed bundle-forming pilus, which is associated with the formation of bacterial microcolonies on cultured epithelial cells. Bacterial attachment and effacement of the enterocyte brush border membrane is attributed to a surface outer membrane protein adhesin termed intimin and EPEC-secreted proteins EspA, EspB, and EspD. Except for intimin, production in vivo or antibody response against these virulence determinants during natural EPEC infections in young children has not been demonstrated. Antibody responses against BfpA, intimin, EspA, and EspB were investigated in Brazilian children naturally infected with EPEC. Generally, IgG antibodies against BfpA and EspB were the most commonly found, followed by anti-EspA and intimin antibodies. Thus, bundle-forming pilus and locus of enterocyte attachment-encoded products are produced in vivo during natural EPEC infections and elicit an immune response against heterologous EPEC virulence determinants. These findings have important implications in the immunoprophylaxis against EPEC infections.     

Baculovirus-mediated gene transfer in the presence of human serum or blood facilitated by inhibition of the complement system

Baculovirus vectors are efficient tools for gene transfer into hepatocytes in vitro. However, gene transfer is strongly reduced in the presence of native sera, providing an explanation for the failure of direct application of the virus in vivo. In this study, we define the role of the complement (C) system (C) as a major cause for baculovirus inactivation in human serum. Baculoviruses most likely activate the classical pathway of the C system and assembly of very late C components is required for inactivation of the vector. We demonstrate the survival of baculovirus vectors in human serum through treatment with a functional blocking antibody against C component 5. Inactivation of baculovirus in human plasma and whole blood was prevented by treatment with cobra venom factor. The data reveal various interactions of baculovirus vectors with the C system and will lead to facilitation of baculovirus-mediated gene transfer into hepatocytes in vivo by protection of the vector from C inactivation.     

Inhibition of reaper-induced apoptosis by interaction with inhibitor of apoptosis proteins (IAPs)

IAPs comprise a family of inhibitors of apoptosis found in viruses and animals. In vivo binding studies demonstrated that both baculovirus and Drosophila IAPs physically interact with an apoptosis-inducing protein of Drosophila, Reaper (RPR), through their baculovirus IAP repeat (BIR) region. Expression of IAPs blocked RPR-induced apoptosis and resulted in the accumulation of RPR in punctate perinuclear locations which coincided with IAP localization. When expressed alone, RPR rapidly disappeared from the cells undergoing RPR-induced apoptosis. Expression of P35, a caspase inhibitor, also blocked RPR-induced apoptosis and delayed RPR decline, but RPR remained cytoplasmic in its location. Mutational analysis of RPR demonstrated that caspases were not directly responsible for RPR disappearance. The physical interaction of IAPs with RPR provides a molecular mechanism for IAP inhibition of RPR's apoptotic activity.     

Transport of glucose and leucine by intestinal membrane vesicles in genetic diabetes

Na+-dependent D-glucose and L-leucine uptakes by isolated small intestinal brush-border membrane vesicles were studied in normal and genetically diabetic mice (C57BL/KsJ-dbm). Vesicles from normal mice demonstrated transport characteristics and morphological appearances identical to those from other mammalian small intestinal brush-border membrane isolates. There was no difference found between genetically diabetic mice and their littermate controls. These data suggest that the small intestinal brush-border membrane transport is not altered in genetic diabetes in contrast to that found in drug-induced diabetes.     

Treatment of arterial femoropopliteal obstructions with Palmaz midsize stents]

We evaluated the dose-dependent (saturable) gastrointestinal absorption of cefatrizine, an aminocephalosporin transported by peptide carriers, in rats by a physiological mechanism-based approach to clarify its absorption characteristics and to examine the in vitro (in situ)-in vivo correlation in intestinal transport. With an increase in oral dose (mumol/5 ml/kg) from 5 (low) to 50 (high), the intestinal absorption rate constant (ka), which was estimated by analysis of gastrointestinal disposition, decreased markedly, from 0.301 to 0.056 min-1. This decrease was ascribable to the saturability of intestinal membrane transport, of which the concentration dependency in the perfused intestine was similar in extent to the dose dependency in ka. However, the apparent absorption rate constant (ka'), which was estimated by analysis of plasma concentrations after oral administration, decreased only modestly from 0.037 to 0.023 min-1. This was associated with the result that, at the low dose, ka' was far smaller than ka and comparable with k(g) (gastric emptying rate constant), suggesting gastric emptying-limited absorption. At the high dose, where intestinal cefatrizine absorption was less efficient, ka' was closer to ka than k(g). It was also observed that the bioavailability was close to unity, independent of dose, suggesting that the intestinal transit time is long enough to achieve complete absorption, even at the high dose, where intestinal cefatrizine absorption is less efficient. Thus, it was found that the effect of saturability in the intestinal transport of cefatrizine is apparently attenuated in its overall gastrointestinal absorption because of the involvement of gastric emptying and intestinal transit time as additional physiological factors to define absorption. It was also found that a scaling factor is required to correlate the intestinal membrane transport between in vitro (in situ) and in vivo, though this remains to be verified to be utilized for developing oral drug delivery strategies and optimizing oral drug therapy.     

Helix pomatia lectin, an inducer of Drosophila immune response, binds to hemomucin, a novel surface mucin

We describe the isolation and initial characterization of hemomucin, a novel Drosophila surface mucin that is likely to be involved in the induction of antibacterial effector molecules after binding a snail lectin (Helix pomatia A hemagglutinin). Two proteins of 100 and 220 kDa were purified from the membrane fraction of a Drosophila blood cell line using lectin columns. The two proteins are products of the same gene, as demonstrated by peptide sequencing. The corresponding cDNAs code for a product that contains an amino-terminal putative transmembrane domain, a domain related to the plant enzyme strictosidine synthase, and a mucin-like domain in the carboxyl-terminal part of the protein. The gene is expressed throughout development. In adult flies, high expression is found in hemocytes, in specialized regions of the gut, and in the ovary, where the protein is deposited onto the egg surface. In the gut, the mucin co-localizes with the peritrophic membrane. The cytogenetic location of the gene is on the third chromosome in the region 97F-98A.     

Functionality and cell anchorage dependence of the African swine fever virus gene A179L, a viral bcl-2 homolog, in insect cells

The African swine fever virus gene A179L has been shown to be a functional member of the ced9/bcl-2 family of apoptosis inhibitors in mammalian cell lines. In this work we have expressed the A179L gene product (p21) under the control of the baculovirus polyhedrin promoter using a baculovirus system. Expression of the A179L gene neither altered the baculovirus replication phenotype nor delayed the shutoff of cellular protein synthesis, but it extended the survival of the infected insect cells to very late times postinfection. The increase in cell survival rates correlated with a marked apoptosis reduction after baculovirus infection. Interestingly, prevention of apoptosis was observed when recombinant baculovirus infections were carried out in monolayer cell cultures but not when cells were infected in suspension, suggesting a cell anchorage dependence for p21 function in insect cells. Cell survival was enhanced under optimal conditions of cell attachment and cell-to-cell contact as provided by extracellular matrix components or poly-D-lysine. Since it was observed that cytoskeleton organization varied depending on culture conditions of insect cells (grown in monolayer versus grown in suspension), these results suggested that A179L might regulate apoptosis in insect cells only when the cytoskeletal support of intracellular signaling is maintained upon cell adhesion. Thus, cell shape and cytoskeleton status might allow variations in intracellular transduction of signals related to cell survival in virus-infected cells.     

Biochemical composition of human peripheral arteries examined with near-infrared Raman spectroscopy

OBJECTIVE: To describe the clinical, serologic, and immunogenetic features of familial idiopathic inflammatory myopathy (IIM) and to compare these with the features of sporadic IIM. METHODS: Clinical signs and symptoms, autoantibodies, HLA-DRB1 and DQA1 alleles, and GM/KM phenotypes were compared among 36 affected and 28 unaffected members of 16 unrelated families in which 2 or more blood relatives developed an IIM. In addition, findings in patients with familial IIM were compared with those in 181 patients with sporadic IIM. The families included 3 pairs of monozygotic twins with juvenile dermatomyositis, 11 families with other siblings or relatives with polymyositis or dermatomyositis, and 2 families with inclusion body myositis. RESULTS: The clinical features of familial IIM were similar to those of sporadic IIM, although the frequency of myositis-specific autoantibodies was lower in familial than in sporadic IIM. DRB1*0301 was a common genetic risk factor for familial and sporadic IIM, but contributed less to the genetic risk of familial IIM (etiologic fraction 0.35 versus 0.51 in sporadic IIM). Homozygosity at the HLA-DQA1 locus was found to be a genetic risk factor unique to familial IIM (57% versus 24% of controls; odds ratio 4.2, corrected P = 0.002). CONCLUSION: These findings emphasize that 1) familial muscle weakness is not always due to inherited metabolic defects or dystrophies, but may be the result of the development of IIM in several members of the same family, and 2) multiple genetic factors are likely important in the etiology and disease expression of familial IIM, as is also the case for sporadic myositis, but DQA1 homozygosity is a distinct risk factor for familial IIM.     

Cardiovascular dysfunction related to threat, avoidance, and vigilant work: application of event-related potential and critique

Bacillus thuringiensis is a Gram-positive bacterium, widely used in agriculture as a biological pesticide. The biocidal activity mainly resides in a parasporal protein inclusion body, or crystal. The inclusion is composed of one or more types of delta-endotoxins (Cry and Cyt proteins). Cry proteins are selectively toxic to different species from several invertebrate phyla: arthropods (mainly insects), nematodes, flatworms and protozoa. The mode of action of the insecticidal proteins is still a matter of investigation; generally, the active toxin is supposed to bind specific membrane receptors on the insect midgut brush-border epithelium, leading to intestinal cell lysis and subsequent insect death by starvation or septicemia. The toxin-encoding cry genes have been extensively studied and expressed in a large number of prokaryotic and eukaryotic organisms. The expression of such genes in transgenic plants has provided a powerful alternative for crop protection.     

Olfactory receptor proteins. Expression, characterization and partial purification

A rat olfactory epithelium cDNA library was screened for olfactory receptor clones. One of the positively hybridizing cDNA clones was sequenced and found to encode a new member of the olfactory receptor superfamily. This cDNA, termed olp4, was used as a model of olfactory receptor for expression, both in vitro and in vivo. Expression of olp4, as well as of another previously cloned olfactory receptor (F5), was monitored by immunoprecipitation was a monoclonal antibody directed against a Flag peptide epitope tag, inserted at the N-terminus of the open reading frame, and a specific polyclonal antibody against a C-terminal peptide of olp4. Translation in vitro, followed by immunoprecipitation, showed a major olp4-specific band of 27-29 kDa. The olp4 and F5 polypeptides were found to be inserted into microsomal membranes as expected for integral membrane proteins. Expression in vivo of Flag-olp4 in Sf9 insect cells, using the baculovirus expression system, showed a specific polypeptide of the same size as the in vitro species, with an additional band of 34 kDa, which is most likely a glycosylated form. Fluorescence cytometry and immunohistochemical assays demonstrated the localization of the Flag-olp4 product on the cell surface of the infected host Sf9 cells, with the N-terminus and C-terminus in the proper orientation. Affinity chromatography was used for the partial purification of the olp4 polypeptide from infected Sf9 cells. The identification and purification of this expressed olfactory receptor polypeptide could open the way for further characterization and functional studies of the olfactory receptor superfamily members.     

Effect of aging on the intestinal transport of hydrophilic drugs in the rat small intestine

The effect of aging on the intestinal transport of hydrophilic drugs (and probe compounds) was investigated in the rat small intestine. Passive transport was suggested to be unchanged with aging from 8 (young) to 54 (old) and further to 101 (very old) weeks old, as shown for D-xylose and urea in single-pass intestinal perfusion (under urethane anesthesia), where steady-state transport across the intestinal membrane into the blood stream was evaluated. The passive transports of cephradine, 5-fluorouracil (5-FU) and L-glucose were also unchanged, though they were compared only between the young and the old. Consistently, the passive uptake in the intestinal everted sacs, where the entry process into the membrane was evaluated for 5-FU, D-xylose, urea and polyethylene glycol (PEG) 900, was unchanged with aging from the young to the very old. The carrier-mediated transport of cephradine was also unchanged with aging from the young to the old in perfusion under anesthesia, though that of D-glucose was declined by about 50% with aging from the young to the old and thereafter remained constant in the very old. In perfusion in unanesthetized rats, age independency in passive transport (examined for cephradine, L-glucose and D-xylose) and an age-dependent decline in D-glucose transport were also observed, suggesting that the findings under anesthesia are not qualitatively distorted. These results suggest that, although carrier-mediated transport may moderately decline with aging, the barrier function of the intestinal membrane to passive permeation of hydrophilic drugs (with molecular weight below 1000) may be unaffected by aging, supporting the suggestion from our previous in vivo studies that age-dependent increases in the orally absorbed fraction may be predicted for incompletely absorbed drugs because of delayed intestinal transit rather than increased intestinal transport (membrane permeability).     

Quantitative analysis of the intrinsic muscles of the foot

In the Homopteran order of insects, the plant xylem feeders exhibit a highly differentiated part of their digestive tract known as the filter chamber. In this tissue, water crosses plasma membranes through a transepithelial osmotic gradient. In previous studies on the filter chamber of Cicadella viridis, we purified and characterized from the plasma membranes a 25 kDa protein that we demonstrated to be an aquaporin (or water channel, member of the major intrinsic protein family, a group of membrane channels for small solutes). We called this protein AQPcic for Cicadella aquaporin. In the present study, we used polyclonal antibody anti-AQPcic in Western blotting and immunocytochemical analysis of the intestinal tract of Cercopis sanguinolenta, Philaenus spumarius, Aphrophora alni (Cercopidae), Euscelidius variegatus, and Scaphoideus titanus (Jassidae). Western blotting experiments revealed that immunologically related AQPcic proteins are found in those species. The molecular weight of these proteins is 15-26 kDa. Immunocytochemical studies on ultrathin filter-chamber sections revealed that the anti-AQPcic antibody systematically labelled the membrane microvilli of epithelial cells. A good correlation thus exists between the physiology of these cells and the presence of aquaporin-related proteins in their membranes.