Microclimate and Animal Life in the Equatorial Mountains

The venom apparatus in both species of Dendroaspis shows great similarity to that described in other proteroglyphs. There is a posterior bulbous portion or main gland and an anterior narrower portion, the accessory gland, that surrounds the secretory duct. The gland is enclosed in a very tough connective tissue capsule. Fibres from the m. adductor externus superficialis insert on the connective tissue capsule on the dorsal aspect of the venom gland. They serve to compress the gland and expel the venom when the snake strikes. Ventrally, fibres of the m. pterygoideus are also inserted on the investing sheath. This muscle supports the gland ventrally and also appears to play some role in venom ejection. The arrangement of the jaw musculature is similar in both species of Dendroaspis. Since the m. adductor externus superficialis is closely associated with the venom gland it has become highly specialized and exhibits great variation among snakes. This muscle in Dendroaspis differs from that in other proteroglyphs in the extension of its origin in a ventral direction over the postorbital bone to the maxilla. As in other elapids, the m. levator anguli oris is absent in both species of Dendroaspis.     

The Effects of Salivary Gland Extracts from <Emphasis Type="Italic">Boophilus microplus</Emphasis> Ticks on Mitogen-stimulated Bovine Lymphocytes

The effect of salivary gland extract (SGE) from the tick Boophilus microplus was examined in mitogen-stimulated lymphocytes in vitro. SGE was added to lymphocytes of seven cattle together with the mitogens concanavalin A (ConA), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). Semi-purified B cells from another seven cattle were stimulated with the mitogen lipopolysaccharide (LPS). PHA and ConA stimulated proliferation of lymphocytes to the same extent, but the inhibition due to SGE of Boophilus microplus on the proliferative response stimulated by PHA (39.0% ± 9.3%) was less than the inhibition of proliferative response stimulated by ConA (75.4% ± 6.9%). In contrast, SGE of B. microplus stimulated the proliferation of B cells in the presence of LPS in a dose-dependent manner. Enhanced stimulation of B cells by SGE at >4 μg in culture was greater than twice that observed when B cells were stimulated by LPS alone. SGE does not have a direct suppressive effect on bovine B cell proliferation; however, in vivo the effectiveness of B cell responses might be influenced by other immune factors, such as cytokine profiles.     

Staining properties of the luminal epithelium of the isthmus and shell gland of the oviduct of the hen Gallus domesticus during the passage of an egg

The effect of a developing egg on the staining properties of the luminal epithelium of the isthmus and shell gland of the oviduct of the hen Gallus domesticus is described, with special reference to the red region. Using histochemical methods for the demonstration of complex mucopolysaccharides, the staining reactions in the surface epithelium adjacent to an egg were found to be similar to those seen in an empty oviduct. With the empirical methods for intracellular calcium, a staining reaction was seen in cells which were adjacent to an egg. There was no reaction in an empty oviduct. If an egg lay between the red region and the shell gland, methods for the demonstration of acid mucopolysaccharides or intracellular calcium showed a more pronounced reaction in an area of surface cells at the neck of the shell gland. These results are based on recently defined anatomical regions.     

Expression of oestrogen and progesterone receptors in canine sebaceous gland tumours

Sebaceous gland oestrogen α (ERα) and progesterone (PR) receptor expression was examined immunohistochemically in 26 and 32 dogs respectively with sebaceous gland hyperplasia/adenomas, epitheliomas and carcinomas, and in the glands of 10 healthy controls. The mean percentage of ERα positive nuclei in control sebaceous glands was 21.31% compared with 11.5% in hyperplasia/adenoma‐type lesions, although these values were not statistically different. In sebaceous gland epitheliomas and carcinomas, positive basal cells represented 7.86% and 3.53% of neoplastic cells respectively and these mean percentages were significantly lower in epitheliomas (P < 0.024) and carcinomas (P < 0.015) than in controls. The mean percentage of PR‐positive nuclei in control sebaceous glands was 23.96%, similar to the 22.07% found in hyperplasia/adenoma‐type lesions. In sebaceous gland epitheliomas and carcinomas, positive cells were scarce and represented 13.5% and 4.06% of neoplastic cells respectively. Differences in the percentage of positive cells between normal and pathological glands reached statistical significance for carcinomas (P < 0.043). In the control group there was greater PR (P < 0.001) and ERα expression (P < 0.014) in sebaceous glands in female dogs. The PR and ERα immunoreactivity in each category of neoplastic lesions could not be analysed because sample size was too small but when all the sebaceous gland tumours were grouped and analysed, no sex difference was found. The results suggest that oestrogen and progesterone receptor expression is reduced in some canine sebaceous gland tumours. These changes may represent a contributing factor for tumour growth or simply be a consequence of tumour progression.     

Treating Animal Bites: Susceptibility of Staphylococci from Oral Mucosa of Cats

Infected wounds determined by cats’ bites represent high costs to public health, and their adequate treatment relies on the knowledge of the antimicrobial susceptibility of bacterial agents found in the oral microbiota. Members of the genus Staphylococcus sp. belong to the microbiota of the oral mucosa of cats and are frequently involved in secondary infections of these wounds. This study aimed to evaluate the antimicrobial susceptibility of Staphylococcus species isolated from oral mucosa of cats. Samples were collected from 200 clinically healthy cats and processed by standard bacteriological methods and tested for susceptibility to a panel of 16 antimicrobials. A total of 212 staphylococci isolates were obtained from 141 of the 200 cats (70.5%), and more than one colony was recognized in 53 cases. Coagulase‐negative species were most frequently found (89.6%) distributed among Staphylococcus xylosus (50.9%), Staphylococcus felis (27.4%), Staphylococcus simulans (6.1%) and Staphylococcus sciuri (5.2%). Coagulase‐positive species (10.4%) were distributed among Staphylococcus aureus (4.7%) and Staphylococcus intermedius group (SIG) (5.7%). Regarding to antimicrobial resistance, 178 isolates (83.9%) were resistant to at least one antimicrobial, and rifampicin showed the best results with 100% of sensitive strains. Conversely, high rates of resistance were observed for penicillin and tetracycline (56.1%). The 212 staphylococci isolates and 30 (14.1%) strains were resistant to methicillin (on the disc susceptibility test) and may be preliminarily considered as methicilin‐resistant staphylococci. In conclusion, this study reports important rates of antimicrobial resistance among the species of Staphylococcus isolated from clinical specimens of cats, which must be considered for the treating of cats’ bites in humans.     

金黄色葡萄球菌诱发建立乳房炎小鼠病理模型

为了建立小鼠乳房炎模型,将30只昆明小鼠随机分成3组,分别经第4对乳腺注入50μL的生理盐水、1.0×105CFU/mL和2.0×105CFU/mL的金黄色葡萄球菌,观察乳腺组织的外形和组织切片的变化;结果表明,注菌后24 h,小鼠出现明显的临床症状,乳腺出现不同程度的炎性症状,组织病理学显示腺泡腔内有大量嗜中性粒细胞浸润,泡腔间隔增宽。说明金黄色葡萄球菌能够诱发试验性乳房炎。     

Protein and mRNA expression of follicle‐stimulating hormone receptor and luteinizing hormone receptor during the oestrus in the yak (Bos grunniens)

Follicle‐stimulating hormone (FSH) and luteinizing hormone (LH) have a central role in follicle growth, maturation and oestrus, but no clear pathway in the seasonal oestrus of yak (Bos grunniens) has been found. To better understand the role of FSH and LH in seasonal oestrus in the yak, six yaks were slaughtered while in oestrus, and the pineal gland, hypothalamus, pituitary gland, and gonads were collected. Using real‐time PCR and immunohistochemical assays, we determined the mRNA and protein expression of the FSH and LH receptors (FSHR and LHR) in these organs. The analysis showed that the FSHR mRNA expression level was higher in the pituitary gland tissue compared with LHR (p < .01) during oestrus. By contrast, there was low expression of FSHR and LHR mRNA in the pineal gland and hypothalamus. FSHR mRNA expression was higher than that of LHR (p < .05) in the ovary, whereas LHR mRNA expression was higher than that of FSHR (p < .01) in the uterus. FSHR and LHR proteins were located in the pinealocyte, synaptic ribbon and synaptic spherules of the pineal gland and that FSH and LH interact via nerve fibres. In the hypothalamus, FSHR and LHR proteins were located in the magnocellular neurons and parvocellular neurons. FSHR and LHR proteins were localized in acidophilic cells and basophilic cells in the pituitary gland, and in surface epithelium, stromal cell and gland epithelium in the uterus. In the ovary, FSHR and LHR protein were present in the ovarian follicle. Thus, we concluded that FSHR and LHR are located in the pineal gland, hypothalamus, pituitary and gonad during oestrus in the yak. However, FSHR was mainly expressed in the pituitary gland and ovaries, whereas LHR was mainly expressed in the pituitary gland and uterus.     

Light and Electron Microscopic Study of Perineal Gland in the Grasscutter (Thryonomys Swinderianus, Temminck 1827)

The perineal glands were identified in the zona cutanea of the anal canal of males more than 4 months old. These glands are organized on a lobular model made up of sebaceous cells and isolated by connective parietal cells. The paler in colour the sebaceous cells, the more lipid vacuoles they contain. PAS-negative and Sudan III-positive secretions were demonstrated in these cells. Electron microscopy showed that the intracellular organelles were well-developed, which is a mark of high metabolic activity and storage by the glandular cells. Cystic vesicles were found in the lobules. The size and number of these cysts were variable. The position of the cyst cells and the variability of their size suggest that they are formed after lysis of some holocrine secretory cells. These observations suggest a progressive maturation of the gland towards its secretory site. No specific secretory duct for the purpose of draining secretions was observed, however, there were possible discharge pathways, although with no real walls, as is found for the biliary canaliculi.     

Anatomical and Immunohistochemical Characteristics of the Prostate Gland in the Greater Cane Rat (Thryonomys swinderianus)

This study examined the morphology and immunohistochemical features of the prostate gland in 15 captive‐reared male greater cane rat of known reproductive and medical history. Samples of the glands were taken after gross examination and routinely prepared for both histological and ultrastructural analysis. Immunohistochemistry was also carried out on paraffin‐embedded sections of the glands using rabbit polyclonal antibodies against oestrogen receptors (ERα and ERβ) and mouse monoclonal antibody for the progesterone receptor (PR). The prostate, which constitutes 0.04% of the body weight, was a paired, lobulated, brownish gland having three left and four right lobes that partly cover the pelvic urethra. Based on the amount and arrangement of the secretory epithelial folding and relative to their distances to the urethra, two histological zones, the central and peripheral, were identified. However, the epithelium of both zones was lined by predominantly simple cuboidal cells with occasional basal cells. The main ultrastructural features of these cuboidal cells were the presence of several nuclear pores on the nucleus, moderately well‐developed, short microvilli and bleb‐like apical projections, as well as inter‐cellular lacunae seen between these cells and the basal cells. The cuboidal epithelial cells also showed positive nuclear staining for ERα and ERβ but not for PR. It is however interesting that the ERα‐positive staining was more at the epithelial cells, which is uncommon. These findings highlight the peculiarities in the structure and ultrastructure as well as the unique expression of the oestrogen receptors in the prostate gland of the greater cane rat.     

Ex vivo generation of mature equine monocyte-derived dendritic cells

Dendritic cells (DCs) are innate immune cells specialized in antigen detection and presentation. They perform an essential role in initiating and guiding the immune response, the direction of which largely depends upon the activation state of the DCs. The objective of this study was to generate mature equine monocyte-derived DCs and, in doing so, to develop a method for measuring the activation state of these cells. Equine DCs were stimulated with UV-inactivated Escherichia coli (E. coli), and the activation status was measured by analyzing cell surface marker expression, cytokine production, and endocytic capacity. Comparisons for each parameter measured were performed between macrophages, non-stimulated DCs and stimulated DCs. Equine monocyte-derived DCs may be distinguished from macrophages based on cell surface expression of MHC class II (p < 0.0001) and CD206 (p < 0.0001), their capacity for endocytosis of FITC-dextran (p < 0.05), and production of TNF-α upon stimulation (p < 0.001). Furthermore, stimulated DCs can be distinguished from non-stimulated DCs based on increased cell surface expression of MHC class II (p < 0.0001) and upregulation of pro-inflammatory cytokine mRNA, particularly IL-12/IL-23p40 (p < 0.05) and IL-23p19 (p < 0.05). The ability to measure DC activation state will facilitate future investigations of equine DC function.     

Some toxicity thresholds for the clinical effects of common tiger snake (Notechis scutatus) envenomation in the dog

SUMMARY Common tiger snake (Notechis scutatus) venom was administered experimentally to dogs at doses from 0.25 lethal dose (LD) to 20 LD. Haemolysis and increased creatine kinase values occurred rapidly after injection of sublethal (subparalytic) doses, but the clotting time of blood was extended and blood became incoagulable only when dogs were dosed with 10 LD or more of venom. Haemolysis, although of a low threshold of toxicity, was not severe and should not greatly affect the lethality of the venom. Coagulopathy is a sign that the dog has been lethally envenomed and will need to be given antivenom if skeletal muscle paralysis is to be overcome.     

Blood and milk cellular immune responses of mastitic non-periparturient cows inoculated with Staphylococcus aureus

Lymphocyte function and phenotype of peripheral blood and mammary gland cells were evaluated in non-periparturient cows before and at 1, 4 to 8 and 9 to 14 d after inoculation with Staphylococcus aureus, as expressed by percentage of CD3+, CD2+, and CD45R+ cells, antigen density of these markers per lymphocyte, and mitogen-induced blastogenesis. Milk bacterial counts and somatic cell counts (SCC) were also assessed. Mitogen-induced blastogenic responses were strong in blood and weak in mammary gland cells in all observations and positively correlated with the percent of CD45R+ cells. Significantly greater percentages of milk CD3+ lymphocytes and increased CD3, CD2, and CD45R antigen density per cell were observed after challenge. The blood CD3 and CD2 antigen density per lymphocyte and the milk CD2+ lymphocyte percent were negatively correlated with SCC (P ≤ 0.01). No mastitis (SCC ≤ 500 000 cells/mL) was observed in cows showing blood lymphocyte CD2 and CD3 antigen density indices ≥ 2.5 and 6, respectively. Forty-one percent of SCC values were predicted by the combined blood CD2 and milk CD3 antigen density (P ≤ 0.01). These findings support the hypotheses that mitogen-induced lymphocyte blastogenesis is not a valid test to assess mammary gland immunocompetence and that CD2 expression may facilitate immune responses by decreasing the number of T cell receptors required to achieve full activation.     

The ultrastructural localisation of acid phosphatase in the avian shell gland

The location of non‐specific acid phosphatase in the shell gland of the laying fowl was investigated at ultrastructural level. Free acid phosphatase occurred principally in the basal non‐ciliated surface epithelial cells during the first four hours of calcium deposition. Membrane‐bound acid phosphatase (i.e. lysosomal) was observed only in the tubular gland cells. A cyclical fluctuation in lysosome numbers was noted.     

Apoptosis of resident and inflammatory macrophages before and during the inflammatory response of the virgin bovine mammary gland

Background

Macrophages may play a prominent role in defense of the bovine mammary gland, and their functionality is necessary for successful eradication of bacterial pathogens. In contrast to necrosis, however, apoptosis has not yet been studied in macrophages from bovine mammary glands. Therefore, the aim of this study was to confirm the occurrence of apoptosis in macrophages from resting heifer mammary glands and during the inflammatory response.

Methods

Inflammatory response was induced by phosphate buffered saline (PBS) and by lipopolysaccharide (LPS). Resident macrophages (_RESMAC) were obtained before and inflammatory macrophages (_INFMAC) 24, 48, 72 and 168 hours after inducing inflammatory response in mammary glands of unbred heifers. Cell samples were analyzed for differential counts, apoptosis and necrosis using flow cytometry.

Results

Populations of _RESMAC and _INFMAC contained monocyte-like cells and vacuolized cells. Apoptosis was detected differentially in both morphologically different types of _RESMAC and _INFMAC and also during initiation and resolution of the inflammatory response. In the _RESMAC population, approximately one-tenth of monocyte-like cells and one-third of vacuolized cells were apoptotic. In the _INFMAC population obtained 24 h after PBS treatment, approximately one-tenth of monocyte-like cells and almost one-quarter of vacuolized cells were apoptotic. At the same time following LPS, however, we observed a significantly lower percentage of apoptotic cells in the population of monocyte-like _INFMAC and vacuolized _INFMAC. Moreover, a higher percentage of apoptotic cells in _INFMAC was detected during all time points after PBS in contrast to LPS. Comparing _RESMAC and _INFMAC, we observed that vacuolized cells from populations of _RESMAC and _INFMAC underwent apoptosis more intensively than did monocyte-like cells.

Conclusions

We conclude that apoptosis of virgin mammary gland macrophages is involved in regulating their lifespan, and it is involved in the resolution process of the inflammatory response.     

Effects of Thymomimetic Drugs and Zinc Supplementation on the Cellular Immune Response in Hydrocortisone‐suppressed Mice

The studies were carried out on Balb/c mice (5–6 weeks of age) exposed to immunosuppression by a single intraperitoneal dose (125 mg/kg) of hydrocortisone. Prior to hydrocortisone injection the mice were treated with diethyldithiocarbamate (DTC) intra‐peritoneally at a dose of 20 mg/kg, five times at 48 h intervals or calf thymus extract (TFX) at a dose of 10 mg/kg, 10 times at 24 h intervals. The two drugs were used per se or in zinc ions interactions, by adding zinc ions (as sulphate salt) to drinking water at a dose of 72 μg/mouse per day. The results obtained in the study show that hydrocortisone injection drastically decreases the number of thymocytes and splenocytes, which is also accompanied by a decreasing weight ratio of the thymus and spleen. The decreasing number of thymic and spleen cells corresponds to a decreasing percentage of CD⁴⁺, CD⁸⁺ and CD¹⁹⁺ splenocytes and double positive CD4⁺CD⁸⁺ thymocytes. Changes in the number of thymic cells affect their activity, which is expressed in a decreased proliferative response of thymocytes stimulated in vitro with concanavalin A (Con A) and phytohaemagglutinin (PHA). It has also been found that a single hydrocortisone dose decreases interleukin (IL)‐1 production by murine intraperitoneal macrophages stimulated in vitro with lipopolysaccharide (LPS) from Escherichia coli. TFX or DTC counteract hydrocortisone‐induced immunosuppression, which is expressed in partial normalization of the total number of thymic and spleen cells, accelerated regeneration of the two lymphatic organs, shorter suppressive action of hydrocortisone on the percentage of CD⁴⁺, CD⁸⁺ splenocytes and double positive (CD4⁺CD⁸⁺) and CD⁴⁺ thymocytes. Furthermore, total counteraction against the suppressive action of hydrocortisone to proliferative activity of thymocytes stimulated in vitro with Con A and PHA was observed. TFX administered prior to hydrocortisone injection partially prevented the suppressive action of the drug on IL‐1 production by intraperitoneal macrophages, but such an effect was not observed with DTC. The immunorestorative effect of TFX and DTC was augmented by zinc supplementation. The results obtained in the study show that neither TFX nor DTC administration per se and in interaction with zinc supplementation were able to change the suppressive effect of hydrocortisone on the percentage of B splenocytes (CD19⁺ cells).     

Histochemical Analysis of Glycoconjugates in the Skin of a Catfish (Arius Tenuispinis, Day)

A histochemical study using conventional carbohydrate histochemistry (periodic‐acid staining including diastase controls, alcian blue staining at pH 1 and 2.5) as well as using a battery of 14 fluorescein isothiocyanate (FITC)‐labelled lectins to identify glycoconjugates present in 10 different areas of the skin of a catfish (Arius tenuispinis) was carried out. The lectins used were: mannose‐binding lectins (Con A, LCA and PSA), galactose‐binding lectins (PNA, RCA), N‐acetylgalactosamine‐binding lectins (DBA, SBA, SJA and GSL I), N‐acetylglucosamine‐binding lectins (WGA and WGAs), fucose‐binding lectins (UEA) and lectins which bind to complex carbohydrate configurations (PHA E, PHA L). Conventional glycoconjugate staining (PAS staining, alcian blue at pH 1 and 2.5) showed that the mucous goblet cells contain a considerable amount of glycoconjugates in all locations of the skin, whereas the other unicellular gland type, the club cells, lacked these glycoconjugates. The glycoproteins found in goblet cells are neutral and therefore stain magenta when subjected to PAS staining. Alcian blue staining indicating acid glycoproteins was distinctly positive at pH 1, but gave only a comparable staining at pH 2.5. The mucus of the goblet cells therefore also contains acid glycoproteins rich in sulphate groups. Using FITC‐labelled lectins, the carbohydrate composition of the glycoproteins of goblet cells could be more fully characterized. A distinct staining of the mucus of goblet cells was found with the mannose‐binding lectins LCA and PSA; the galactosamine‐binding lectins DBA, SBA and GLS I; the glucosamine‐binding lectin WGA; and PHA E which stains glycoproteins with complex carbohydrate configurations. No reaction occurred with the fucose‐binding lectin UEA and the sialic acid‐specific lectin SNA. In addition, the galactose‐binding lectins PNA and RCA showed only a weak or completely negative staining of the mucus in the goblet cells. The specificity of the lectin staining could be proved by inhibiting binding of the lectins by competitive inhibition with the corresponding sugars. From these data, we can conclude that the mucus produced by the epidermal goblet cells of A. tenuispinis is rich in mannose, N‐acetylgalactosamine and N‐acetylglucosamine residues.     

Microbial Pollution in Water and Its Effect on Fish

Abstract

A systematic study of microbial contamination of fish grown in ponds in and around Calcutta was initiated as part of the wetland management project in the city. Ponds were either sewage-fed or conventional (i.e., fed by rain and groundwater). Fish from these ponds are used for human consumption, and therefore a quantitative analysis of their microbial content is necessary. When concentrations of Escherichia coli, Salmonelleae (unidentified species), and Staphylococcus aureus in water and different organs of fish from sewage-fed and conventional ponds were compared, water and fish organs from conventional ponds contained about two orders of magnitude more bacterial cells. We tested for Salmonelleae and S. aureus, in addition to E. coli, because of persistent reports from Calcutta hospitals that most enteric and other infectious diseases in this region are caused by these bacteria. Significant linear correlations were found between concentrations of these bacteria in pond water and their recovery from several tissues of the fish.     

MicroRNA‐145 regulates immune cytokines via targeting FSCN1 in Staphylococcus aureus‐induced mastitis in dairy cows

Dairy cow mastitis is a detrimental factor in milk quality and food safety. Mastitis generally refers to inflammation caused by infection by pathogenic microorganisms. Our studies in recent years have revealed the role of miRNA regulation in Staphylococcus aureus‐induced mastitis. In the present study, we overexpressed and suppressed miR‐145 to investigate the function of miR‐145 in Mac‐T cells. Flow cytometry, ELISA and EdU staining were used to detect changes in the secretion of several Mac‐T cytokines and in cell proliferation. We found that overexpression of miR‐145 in Mac‐T cells significantly reduced the secretion of IL‐12 and TNF‐α, but increased the secretion of IFN‐γ; the proliferation of bovine mammary epithelial cells was also inhibited. Using quantitative real‐time PCR (qRT‐PCR), Western blotting and luciferase multiplex verification techniques, we found that miR‐145 targeted and regulated FSCN1. Knock‐down of FSCN1 significantly increased the secretion of IL‐12, while the secretion of TNF‐α was significantly downregulated in Mac‐T cells. Upon S. aureus infection of mammary gland tissue, the body initiated inflammatory responses; Bta‐miR‐145 expression was downregulated, which reduced the inhibitory effect on the FSCN1 gene; and upregulation of FSCN1 expression promoted mammary epithelial cell proliferation to allow the recovery of damaged tissue. The results of the present study will aid in understanding the immune mechanism opposing S. aureus infection in dairy cows and will provide a laboratory research basis for the prevention and treatment of mastitis.     

Purification of equine neutrophil lysozyme and its antibacterial activity against Gram-positive and Gram-negative bacteria

Lysozyme from equine neutrophil granulocytes was isolated in a pure form by fast performance liquid chromatography, i.e. ion-exchange chromatography and reversed-phase chromatography. The lysozyme lysed Micrococcus luteus, Bacillus subtilis and Staphylococcus lentus and was also bactericidal against the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae, Bordetella bronchiseptica, and Serratia marcescens. Staphylococcus aureus and Staphylococcus epidermidis were not lysed. The lysozyme was only very slightly bactericidal for S. epidermidis and S. aureus. Equine neutrophil lysozyme was found to be bactericidal for Gram-positive as well as for Gram-negative bacteria without further treatment. Equine and chicken egg white lysozymes were found to be immunologically related when examined using specific antisera against each of them. Both lysozymes also had very similar specific enzymatic activities against M. luteus membranes.