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Chinese Journal of Biology
Volume 2014 (2014), Article ID 219392, 7 pages
http://dx.doi.org/10.1155/2014/219392
Research Article

Antimicrobial Activity of Cladonia verticillaris Lichen Preparations on Bacteria and Fungi of Medical Importance

1Departamento de Bioquímica, CCB, Universidade Federal de Pernambuco, Avenida Professor Moraes Rego s/n, Cidade Universitária, 50670-420 Recife, PE, Brazil
2Departamento de Ciências Animais, Universidade Federal Rural do Semi-Árido, 59625-900 Mossoró, RN, Brazil

Received 22 October 2013; Accepted 27 November 2013; Published 22 January 2014

Academic Editors: B. Martinac and Z. Qiusheng

Copyright © 2014 Dalila de Brito Marques Ramos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Cladonia verticillaris lichen lectin (ClaveLL) was purified using a previously established protocol and then evaluated for its potential antimicrobial activity. Initially, the autochthonous lichen was submitted to extraction with sodium phosphate buffer pH 7.0, followed by filtration and centrifugation to obtain crude extract. A salt fractionation was performed with 30% ammonium sulfate. After centrifugation, the protein fraction was loaded onto molecular exclusion chromatography using Sephadex G-100 matrix to purify active lectin. ClaveLL showed antibacterial activity against Gram-positive (Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis) and Gram-negative (Escherichia coli and Klebsiella pneumoniae) assayed strains, with greater inhibitory effect on growth of E. coli (MIC of 7.18 μg mL−1). The lowest minimum bactericidal concentration (MBC, 57.4 μg mL−1) was detected against E. faecalis. The antifungal assay performed with Trichophyton mentagrophytes, Microsporum gypseum, Trichophyton rubrum, Trichosporon cutaneum, and Trichosporon asahi evaluated crude extract, fraction, and ClaveLL preparations. ClaveLL was the most active against T. rubrum with an inhibition percentage of 35% compared to negative control (phosphate buffer). Extract and fraction showed better activity on growth inhibition of T. mentagrophytes (35%). The results indicate the potential of ClaveLL and other C. verticillaris preparations as antimicrobial agents useful for applications focusing on human health.

1. Introduction

The treatment of diseases caused by bacteria and fungi is becoming an issue of concern, due to the growing emergence of microorganism strains resistant to drugs and opportunistic fungi that cause serious infections in humans [1, 2]. Microbial resistance is a genetic phenomenon, in which the microorganisms have genes that encode biochemical mechanisms which prevent drug actions. It may be caused by mutations in the reproductive process of the microorganisms or by imported genes acquired through transduction, conjugation, and transformation mechanisms [3]. Microbial resistance is sometimes due to natural evolution of microorganisms; however, it gains importance through the excessive use of antimicrobial substances in medical, agricultural, and veterinary practices [4]. Therefore, the search for new antibiotics from natural sources has increased as an alternative to commercial drugs.

Lichens are symbiotic associations between fungus and one or more algae and/or cyanobacteria [5]. Species of the genus Cladonia have been used in folk medicine to treat respiratory diseases such as throat irritation, cough, asthma, and tuberculosis [6, 7]. The use of lichens in medicine is based on the fact that they contain unique and various biologically active substances, mainly with antimicrobial actions [8, 9]. Cladonia verticillaris is a lichen of cosmopolitan distribution and represents a rich source of lectin (carbohydrate-binding protein). The protocol established for isolation of C. verticillaris lichen lectin (ClaveLL) is simple and yields milligram quantities of protein (18 mg from 20 g of lichen flour) free of secondary metabolites. ClaveLL showed insecticidal activity on termite Nasutitermes corniger [10].

The lichen C. verticillaris produces bioactive secondary metabolites, such as fumarprotocetraric and protocetraric acids. The fumarprotocetraric acid has demonstrated biological actions, such as expectorant, antioxidant, and allelopathic effect [11, 12]. However, little has been done with respect to lichen lectins and their biological properties and potential biotechnological applications.

Lectins with potential for biotechnological applications as antibiotics have been isolated and their structures have been characterized [1315]. Lectins are a heterogeneous group of proteins from no immune origin, containing two or more binding sites for mono or oligosaccharides [16]. Gomes et al. [17] isolated a lectin from leaves of Schinus terebinthifolius that showed antibacterial activity against human pathogenic bacteria and the fungus Candida albicans. Besides being applied to control bacteria and fungi growth, lectins can be used for detection and typing of microorganisms due to the selective interaction between lectins and microorganisms [18].

Fungi known as dermatophytes of the genus Trichophyton and Microsporum cause superficial mycoses affecting the hair, nails, and skin. Trichosporon species have contributed to increased mortality in immunocompromised individuals [19]. Thus, the aim of this study was to evaluate the antimicrobial activity of purified C. verticillaris lichen lectin (ClaveLL) against human pathogenic bacteria Gram-positive (Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Klebsiella pneumoniae) as well as against dermatophyte fungi (Trichophyton mentagrophytes, Microsporum gypseum, Trichophyton rubrum, Trichosporon cutaneum, and Trichosporon asahi).

2. Materials and Methods

2.1. Purification of ClaveLL

C. verticillaris lichen was collected at Alhandra City, State of Paraíba in the Northeastern of Brazil, and gently identified by Dr. Eugênia Cristina Gonçalves Pereira (Departamento de Ciências Geográficas, Centro de Filosofia e Ciências Humanas, UFPE). C. verticillaris lichen lectin (ClaveLL) was obtained through a sequential purification protocol according to Silva et al. [10]. Lichen was dried at 28°C and an overnight extraction (10%, w/v) for 16 h at 28°C was performed in 0.15 M sodium phosphate buffer pH 7.0 containing 0.15 M NaCl (PBS), followed by filtration and centrifugation (3000 g, 4°C, 15 min). The lichen extract was treated with 30% (w/v) ammonium sulphate for 4 h at 28°C. The 0–30% precipitate fraction was obtained by centrifugation (3000 g, 4°C, 15 min), dialyzed for salt removal, submitted to protein quantification, and loaded (18 mg of protein) onto a gel filtration chromatography containing 100 mL of Sephadex G-100 ( cm). The molecular exclusion column was performed using with PBS at a flow rate of 20 mL/h. The collected fractions were monitored for absorbance at 280 nm and hemagglutinating activity.

2.2. Hemagglutinating Activity

Hemagglutinating activity was determined according to method described by Correia et al. [20]. The sample (50 µL) was twofold serially diluted in 0.15 M NaCl on microplate wells. Next, a suspension of 2.5% glutaraldehyde-treated rabbit erythrocytes [21] was added (50 µL) to each well. One hemagglutination unit (titer−1) was defined as the reciprocal of the highest sample dilution which promoted full erythrocyte agglutination. Specific hemagglutinating activity was defined as the ratio between the titer and protein concentration (mg·mL−1).

2.3. Protein Content

Protein concentration was determined according to Lowry et al. [22] using bovine serum albumin as standard (31.25–500 μg mL−1).

2.4. Antibacterial Activity

Gram-positive (Bacillus subtilis ATCC-6633, Staphylococcus aureus ATCC-6538 and Enterococcus faecalis ATCC-6057), and Gram-negative (Escherichia coli ATCC-25922 and Klebsiella pneumoniae ATCC-29665) bacterial strains were provided by the Departamento de Antibióticos, Universidade Federal de Pernambuco, Brazil. Stationary cultures were maintained in nutrient agar (NA) and stored at 4°C. Bacteria were cultured in nutrient broth (NB) and incubated under permanent shaking at 37°C overnight. The culture concentrations were adjusted turbidimetrically at a wavelength of 490 nm to 105-106 colony forming units (CFU)mL−1.

An aliquot of ClaveLL (100 µL; 0.184 µg) was diluted 1 : 1 in NB and then submitted to a series of ten double dilutions, until a final ratio of 1 : 2048. Next, a 180 µL aliquot of each dilution was dispensed into each well of a 96-well microplate. All wells were inoculated with 20 µL of the bacterial culture and incubated at 37°C for 24 h. Assay for each concentration was performed in triplicate. Control wells contained only NB medium and microorganism. After incubation, the optical density at 490 nm (OD490) was measured using a microplate reader. Minimal inhibitory concentration (MIC) was determined as the lowest lectin concentration at which there was ≥50% reduction in OD490 in comparison with the control [23].

To determine the minimal bactericidal concentration (MBC), inoculations (10 µL) from the sample wells at which inhibition of bacterial growth was detected were transferred to NA plates and incubated at 37°C for 24 h. The MBC corresponded to the lowest sample concentration at which no bacterial growth was observed. The assay was performed in triplicate.

2.5. Antifungal Activity

Trichophyton mentagrophytes (URM5541), Microsporum gypseum (URM6199), Trichophyton rubrum (URM5145), Trichosporon cutaneum (URM5743), and Trichosporon asahi (URM5781) were obtained from the Cultures Collection of University Recife Mycologia (URM) from the Departamento de Micologia of the Universidade Federal of Pernambuco (UFPE), Brazil. Antifungal activity was performed according to Wong and Ng [24] with modifications. Fungi were grown at 28°C on potato dextrose agar (PDA) in Petri plates for an 8–15-day period until the surfaces of the plates were completely covered by them. Fungal mycelium discs (0.625 cm in diameter) were removed from the peripheral part of the colonies. ClaveLL (100 µL; 1.67 mg mL−1), lichen extract (100 µL; 9.43 mg mL−1), and 0–30% fraction (100 µL; 40.45 mg mL−1) were spread on solidified PDA medium in Petri plates ( mm2) and a fungal mycelium disk was disposed in the center of the Petri plates. All assays were carried out in triplicate. PBS and nystatin (1 mg/mL) were used as negative and positive controls, respectively. The plates were incubated at 28°C for 72 h. Antifungal activity was indicated by reduction of the fungal growth zone (diameter) in the plates.

2.6. Statistical Analysis

Standard deviations (SD) were calculated using GraphPad Prism version 4.0 for Windows (GraphPad Software, San Diego, CA, USA) and data were expressed as a mean of replicates ± SD. Significant differences between treatment groups from the antifungal assays were analysed by Student’s -test (significance at ) using the Origin 6.0 program.

3. Results and Discussion

Extraction and isolation of pharmacologically active compounds with medicinal importance have received attention in the search for new economically viable alternatives for treating human infections. ClaveLL was purified through a preestablished protocol by Silva et al. [10] using molecular exclusion chromatography on Sephadex G-100 matrix; the column is a viable approach since the same array can be reused efficiently at least 30 times to purify ClaveLL.

Treatment of lichen extract with ammonium sulphate yielded a precipitated protein fraction (0–30% fraction). Chromatography of 0–30% fraction on Sephadex G-100 separated two peaks (Figure 1): the first (corresponding to fractions 7–22) was colorless and showed hemagglutinating activity of 64, corresponding to ClaveLL, with a purification factor of 13.1 times (Table 1). A total of 8.28 mg of ClaveLL were purified from 10 g of C. verticillaris, yield similar to that obtained by Silva et al. [10]. The second peak showed a strong color similar to the fraction and did not show hemagglutinating activity.

tab1
Table 1: Summary of ClaveLL purification.
219392.fig.001
Figure 1: ClaveLL isolated from 0–30% fraction through molecular exclusion chromatography using Sephadex G-100 column (HA in log scale).

ClaveLL revealed antibacterial activity against all tested species, both Gram-positive and Gram-negative. The values for MIC and MBC are shown in Table 2. The antibacterial activity of lectins may occur through the interaction with N-acetylglucosamine (GlcNAc), N-acetylmuramic acid (MurNAc), and tetrapeptides linked to MurNAc present in the cell wall of Gram-positive bacteria or to lipopolysaccharide present in the cell walls of Gram-negative bacteria [25].

tab2
Table 2: MIC and MBC of ClaveLL against bacteria species.

Among the bacteria tested, ClaveLL showed the best inhibitory activity against the Gram-negative bacteria E. coli with MIC value of 7.18 µg mL−1 and the best bactericidal activity against Gram-positive bacteria B. subtilis and E. faecalis with MBC value of 57.4 µg mL−1. Thus, ClaveLL was more efficient in killing Gram-positive than Gram-negative bacteria. Similarly, the isolated lectin from leaves of S. terebinthifolius was more efficient against the Gram-positive Staph. aureus than Gram-negative bacteria such as E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enteritidis [17]. The difference in the susceptibility of Gram-positive and Gram-negative bacteria may be linked to the difficulty of lectins to cross the Gram-negative bacteria outer cell wall to reach the periplasmic space [15]. Additionally, the high level of peptidoglycan (which contains GlcNac) in the cell wall of Gram-positive bacteria may provide more interaction sites for N-acetyl-glucosamine-binding lectins, such as ClaveLL [10].

Costa et al. [14] studied the leaf lectin of Phthirusa pyrifolia (PpyLL) and found MBC of approximately 10 times higher (500 µg mL−1) than ClaveLL for B. subtilis. Instead, Sá et al. [13] found MIC of 2.34 µg mL−1 of the Myracrodruon urundeuva heartwood lectin (MuHL) for this same bacterium, corresponding to a concentration 10 times lower than that of ClaveLL (28 µg mL−1).

Although several lectins purified from various natural sources have shown antibacterial activity [14, 2628], its mechanism of action was not elucidated in detail. It has been proposed that lectins with antibacterial activity form pores in the cell membrane and cell dies as a result of a outflowing of cellular contents [29, 30].

The lichen extract (Figure 2(a)) inhibited the growth of T. mentagrophytes (35%), fungus that was not inhibited by ClaveLL, revealing that the antimicrobial activity of C. verticillaris involves more than one active principle which was removed during lectin purification protocol. Perry et al. [31], studying the antimicrobial activity of 69 species of lichens from New Zealand, found that Cladonia fimbriata extract also inhibited the growth of T. mentagrophytes.

fig2
Figure 2: Growth zones (mm) of the fungi T. mentagrophytes (a), M. gypseum (b), T. rubrum (c), T. cutaneum (d), and T. asahi (e) in PDA medium (-axis) throughout the incubation hours. Each point represents the mean ± SD of three experiments.

The 0–30% fraction was the sample that showed the highest antifungal activity (Figures 2 and 3), inhibiting growth of T. mentagrophytes (37.5%), M. gypseum (42.5%), T. rubrum (38.2%), and T. cutaneum (25%).

fig3
Figure 3: Antifungal activity of lichen extract (a), 0–30% fraction (b), and ClaveLL (c) observed as percentage of growth inhibition in comparison with growth in control. The histograms representing average values of tree measurement of inhibition zones. The * indicates significant differences between treatments and control.

ClaveLL showed highest antifungal activity against T. rubrum (35.3% of inhibition) (Figures 2 and 3). However, ClaveLL (170 μg) was not active against T. mentagrophytes, M. gypseum, and T. cutaneum (Figures 2 and 3). The inhibition of fungi growth can occur through lectin binding to hyphae resulting in poor absorption of nutrients as well as by interference on spore germination process [13]. Antifungal activity of lectins is related to their property to bind carbohydrates such as chitin, a large polymer of N-acetyl-glucosamine, and component of fungal cell wall [20]. The binding of N-acetyl-glucosamine-binding lectins can lead to rupture of the fungal cell wall [32].

The antibacterial and antifungal activities of extract, 0–30% fraction, and ClaveLL are not correlated with secondary metabolites since Silva et al. [10] showed that all these preparations were absent from this class of compounds. The antifungal activity detected for extract and fraction from C. verticillaris  encourages further studies to isolate other lichen compounds to find the chemical constituents responsible for such activity.

4. Conclusion

In conclusion, the lectin purified from C. verticillaris showed antibacterial activity, particularly against Gram-positive bacteria; also, it was able to inhibit the growth of the dermatophyte fungus T. rubrum. ClaveLL and other C. verticillaris preparations are potential antimicrobial agents to be applied for treating human infections.

Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

Acknowledgments

The authors express their gratitude to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for research grants and fellowships (PMGP and LCBBC). The authors are also grateful to the Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE), the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and the Ministério da Ciência, Tecnologia e Inovação (MCTI) for financial support. The authors thank Maria Barbosa Reis da Silva for technical assistance.

References

  1. D. Marchaim, L. Lemanek, S. Bheemreddy, K. S. Kaye, and J. D. Sobel, “Fluconazole-resistant Candida albicans vulvovaginitis,” Obstetrics & Gynecology, vol. 120, pp. 1407–1414, 2012.
  2. N. H. Yim, Y. P. Jung, W. K. Cho et al., “Screening of aqueous extracts of medicinal herbs for antimicrobial activity against oral bacteria,” Integrative Medicine Research, vol. 2, no. 1, pp. 18–24, 2013.
  3. J. Davies and D. Davies, “Origins and evolution of antibiotic resistance,” Microbiology and Molecular Biology Reviews, vol. 74, no. 3, pp. 417–433, 2010. View at Publisher · View at Google Scholar · View at Scopus
  4. P. Srivastava, D. K. Upreti, T. N. Dhole, A. K. Srivastava, and M. T. Nayak, “Antimicrobial property of extracts of Indian lichen against human pathogenic bacteria,” Interdisciplinary Perspectives on Infectious Diseases, vol. 2013, Article ID 709348, 6 pages, 2013. View at Publisher · View at Google Scholar
  5. U. Kaasalainen, D. P. Fewer, J. Jokela, M. Wahlsten, K. Sivonen, and J. Rikkinen, “Cyanobacteria produce a high variety of hepatotoxic peptides in lichen symbiosis,” Proceedings of the National Academy of Sciences of the United States of America, vol. 109, no. 15, pp. 5886–5891, 2012. View at Publisher · View at Google Scholar · View at Scopus
  6. I. Ziment, “Herbal antitussives,” Pulmonary Pharmacology & Therapeutics, vol. 15, no. 3, pp. 327–333, 2002. View at Publisher · View at Google Scholar · View at Scopus
  7. B. Q. Lin, P. B. Li, Y. G. Wang et al., “The expectorant activity of naringenin,” Pulmonary Pharmacology & Therapeutics, vol. 21, no. 2, pp. 259–263, 2008. View at Publisher · View at Google Scholar
  8. N. T. Manojlovic, S. Solujic, and S. Sukdolak, “Antimicrobial activity of an extract and anthraquinones from Caloplaca schaereri,” The Lichenologist, vol. 34, no. 1, pp. 83–85, 2002. View at Publisher · View at Google Scholar · View at Scopus
  9. M. T. Saenz, M. D. Garcia, and J. G. Rowe, “Antimicrobial activity and phytochemical studies of some lichens from south of Spain,” Fitoterapia, vol. 77, no. 3, pp. 156–159, 2006. View at Publisher · View at Google Scholar · View at Scopus
  10. M. D. C. Silva, R. A. Sá, T. H. Napoleão et al., “Purified Cladonia verticillaris lichen lectin: insecticidal activity on Nasutitermes corniger (Isoptera: Termitidae),” International Biodeterioration & Biodegradation, vol. 63, no. 3, pp. 334–340, 2009. View at Publisher · View at Google Scholar · View at Scopus
  11. A. M. Yano-Melo, C. Vicente, and L. Xavier-Filho, “Allelopathic efect of the Cladonia verticillaris lichen extracts and fumarprotocetraric acid on the early growth of germinated seedlings in Allium cepa L.,” Tropical Bryology, vol. 17, pp. 133–139, 1999.
  12. G. M. B. Alves, M. B. S. Maia, E. S. Franco et al., “Expectorant and antioxidant activities of purified fumarprotocetraric acid from Cladonia verticillaris lichen in mice,” Pulmonary Pharmacology & Therapeutics, 2013. View at Publisher · View at Google Scholar
  13. R. A. Sá, F. S. Gomes, T. H. Napoleão et al., “Antibacterial and antifungal activities of Myracrodruon urundeuva heartwood,” Wood Science and Technology, vol. 43, no. 1-2, pp. 85–95, 2009. View at Publisher · View at Google Scholar · View at Scopus
  14. R. M. P. B. Costa, A. F. M. Vaz, M. L. V. Oliva, L. C. B. B. Coelho, M. T. S. Correia, and M. G. Carneiro-da-Cunha, “A new mistletoe Phthirusa pyrifolia leaf lectin with antimicrobial properties,” Process Biochemistry, vol. 45, no. 4, pp. 526–533, 2010. View at Publisher · View at Google Scholar · View at Scopus
  15. E. D. S. Nunes, M. A. A. Souza, A. F. D. M. Vaz et al., “Purification of a lectin with antibacterial activity from Bothrops leucurus snake venom,” Comparative Biochemistry and Physiology B, vol. 159, no. 1, pp. 57–63, 2011. View at Publisher · View at Google Scholar · View at Scopus
  16. P. M. G. Paiva, E. V. Pontual, T. H. Napoleão, and L. C. B. B. Coelho, “Effects of plant lectins and trypsin inhibitors on development, morphology and biochemistry of insect larvae,” in Larvae: Morphology, Biology and Life Cycle, Nova Science, New York, NY, USA, 2012.
  17. F. S. Gomes, T. F. Procópio, T. H. Napoleão, L. C. B. B. Coelho, and P. M. G. Paiva, “Antimicrobial lectin from Schinus terebinthifolius leaf,” Journal of Applied Microbiology, vol. 114, no. 3, pp. 672–679, 2013. View at Publisher · View at Google Scholar
  18. P. M. G. Paiva, F. S. Gomes, T. H. Napoleão, R. A. Sá, M. T. S. Correia, and L. C. B. B. Coelho, “Antimicrobial activity of secondary metabolites and lectins from plants,” in Current Research, Technology and Education Topics in Applied Microbiology and Microbial Biotechnology, pp. 396–406, Formatex Research Center, Badajoz, Spain, 2010.
  19. C. Girmenia, L. Pagano, B. Martino et al., “Invasive infections caused by Trichosporon species and Geotrichum capitatum in patients with hematological malignancies: a retrospective multicenter study from Italy and review of the literature,” Journal of Clinical Microbiology, vol. 43, no. 4, pp. 1818–1828, 2005. View at Publisher · View at Google Scholar · View at Scopus
  20. M. T. S. Correia, L. C. B. B. Coelho, and P. M. G. Paiva, “Lectins, carbohydrate recognition molecules: are they toxic?” in Recent Trends in Toxicology, Y. H. Siddique, Ed., vol. 37, pp. 47–59, Transworld Research Network, Kerala, India, 2008.
  21. D. H. Bing, J. G. Weyand, and A. B. Stavitsky, “Hemagglutination with aldehyde-fixed erythrocytes for assay of antigens and antibodies,” Proceedings of the Society for Experimental Biology and Medicine, vol. 124, no. 4, pp. 1166–1170, 1967. View at Scopus
  22. O. H. Lowry, N. J. Rosebrough, A. L. Farr, and R. J. Randall, “Protein measurement with the Folin phenol reagent,” The Journal of Biological Chemistry, vol. 193, no. 1, pp. 265–275, 1951. View at Scopus
  23. D. Amsterdam, “Susceptibility testing of antimicrobials in liquid media,” in Antibiotics in Laboratory Medicine, V. Loman, Ed., pp. 52–111, Williams & Wilkins, Baltimore, Md, USA, 4th edition, 1996.
  24. J. H. Wong and T. B. Ng, “Sesquin, a potent defensin-like antimicrobial peptide from ground beans with inhibitory activities toward tumor cells and HIV-1 reverse transcriptase,” Peptides, vol. 26, no. 7, pp. 1120–1126, 2005. View at Publisher · View at Google Scholar · View at Scopus
  25. R. Dziarski, M. M. Rasenick, and D. Gupta, “Bacterial peptidoglycan binds to tubulin,” Biochimica et Biophysica Acta, vol. 1524, no. 1, pp. 17–26, 2000. View at Publisher · View at Google Scholar · View at Scopus
  26. A. S. Riera, A. Daud, A. Gallo, S. Genta, M. Aybar, and S. Sánchez, “Antibacterial activity of lactose-binding lectins from Bufo arenarum skin,” Biocell, vol. 27, no. 1, pp. 37–46, 2003. View at Scopus
  27. K. G. Takahashi, T. Kuroda, and K. Muroga, “Purification and antibacterial characterization of a novel isoform of the Manila clam lectin (MCL-4) from the plasma of the Manila clam, Ruditapes philippinarum,” Comparative Biochemistry and Physiology B, vol. 150, no. 1, pp. 45–52, 2008. View at Publisher · View at Google Scholar · View at Scopus
  28. S. M. Kawsar, S. M. Mamun, M. S. Rahman, H. Yasumitsu, and Y. Ozeki, “In-vitro antibacterial and antifungal effects of a 30 kDa D-galactoside-specific lectin from the Demosponge, Halichondria okadai,” International Journal of Biological Sciences, vol. 6, no. 1, pp. 31–37, 2010.
  29. T. Santi-Gadelha, C. A. A. Gadelha, K. S. Aragão et al., “Purification and biological effects of Araucaria angustifolia (Araucariaceae) seed lectin,” Biochemical and Biophysical Research Communications, vol. 350, no. 4, pp. 1050–1055, 2006. View at Publisher · View at Google Scholar · View at Scopus
  30. M. D. L. Oliveira, C. A. S. Andrade, N. S. Magalhães et al., “Purification of a lectin from Eugenia uniflora L. seeds and its potential antibacterial activity,” Letters in Applied Microbiology, vol. 46, no. 3, pp. 371–376, 2008. View at Publisher · View at Google Scholar · View at Scopus
  31. N. B. Perry, M. H. Benn, N. J. Brennan et al., “Antimicrobial, antiviral and cytotoxic activity of New Zealand lichens,” The Lichenologist, vol. 31, no. 6, pp. 627–636, 1999. View at Publisher · View at Google Scholar · View at Scopus
  32. D.-J. Yun, J. I. Ibeas, H. Lee et al., “Osmotin, a plant antifungal protein, subverts signal transduction to enhance fungal cell susceptibility,” Molecular Cell, vol. 1, no. 6, pp. 807–817, 1998. View at Scopus