Printer Friendly

Histological comparison of some fish tissue as biomarker to evaluate water quality from the Red Sea Coast, Jeddah Governorate.

Most of the wadis and the coastal area in Kingdom Saudi Arabia are polluted due to industrial activity. Agriculture activities also contribute to the aquatic pollution mainly due to large-scale use of pesticides and other agrochemicals in this sector. The effects of pesticides and insecticides on fishes and their tolerance, mortality, behavior, accumulation in tissues and induced biochemical and pathological changes have been investigated by some workers from Saudi Arabia (Al-Akel and Shamsi, 2000).

Jeddah is the second largest city in Saudi Arabia located on the eastern coast of the Red Sea and is the major urban center of western Saudi Arabia (Magram, 2009). The city has a population of more than 3.5 million. With the population increase, the amount of sewage became a major problem as the capacity of the sewage treatment plants is largely insufficient and much of the raw sewage (~146,000 [m.sup.3]/day, representing 12 tons of organic matter, PERSGA, 2006) is dumped into the coastal area creating a dramatic environmental impact (El-Rayis, 1990; Basaham, 1998; El-Sayed and Niaz, 1999; El-Sayed, 2002; Turki et al, 2002 and Al-Farawati, 2010).

Histopathological alterations can be used as indicators for the effects of various anthropogenic pollutants on organisms and a reflection of the overall health of the entire population in the ecosystem (Mabika and Barson, 2014).

There have been numerous reports of histopathological changes in liver of fish exposed to a wide range of organic compounds and heavy metals (Abdel, 2012; Au D.W.T, 2004)

Various histological studies have been performed on different fish species in the Red Sea, Jeddah coast (Bin-Dohaish et al, 2004).

Al-Shoaibah area was chosen as the study site because it is "near pristine" aquatic ecosystems as apparently with a rich biodiversity of aquatic ecosystem and was chosen Al-Kumrah site as a polluted area because it is area an slow rate of water turnover and flow of sewage water which is released without any treatment.

The Al-Shoaibah area, therefore serves as an ideal reference site for the description of the histomorphological of various organs in different fish species sampled from an apparently unpolluted natural environment that could be a valuable reference for future toxicological studies.

Two economically important fish species were collected from the Al-Kumrah and Al-Shoaibah regions of the Red Sea. These included L. harak (Forsskal, 1775) and T. jarbua (Forsskal, 1775). They were chosen as sentinel species because they form an integral part of the small-scale commercial, subsistence and recreational fisheries in this ecosystem. Furthermore, many seawater fish species in the sites studied in particular, and in other aquatic ecosystems, are increasingly being used as bio-indicator species for the management of water quality. This is because fish are sensitive to their environment, are easily attainable and have a relatively long lifespan compared to other aquatic organisms, these factors allow for diagnosis of both acute and chronic effects of exposure to pollutants (Abdelrahim et al., 2011; Alturiqi and Albedair, 2012).

The general purpose of this study is to evaluate the effect of different pollutants on the histological structure to the liver, muscles and gills in fish (L. harak and T. jarbua) which collected from two locations (Al-Kumrah and Al-Shoaibah) in Jeddah District along Saudi Arabia Red Sea Coast at summer season 2014 to describe histological abnormalities potential.

To get information about the threat imposed by these spills and influents to these fish species and know whether it is safe for consumption.


Study areas

Sampling sites were selected according to the polluted or unpolluted water concentrations detected during field surveys performed in summer 2013, where the samples were collected between December 2013 and September 2014.

Fish sampling

The fishes sampled were Black-spot emperor (L. harak) and Jarbua terapon (T jarbua) collected from two sampling sites (Al-Kumrah and Al-Shoaibah).

The fishes were identified and collected with the assistance of a staff of the department of biological sciences, University of King Abdulaziz (KAU).

The description of fish species that were collected from different sites is shown in Table (1). Histological examination of the tissues

Portions of the liver, gill and muscles of fishes were fixed immediately on removal from the fish in 10% buffered neutral formalin (BNF) for 72 hours at room temperature. The tissues were grossed on the gross board and placed inside stainless tissue cassettes.

The cassettes were arranged carefully inside the automated tissue processor. Thereafter the tissues were subjected to the following treatments:

Dehydration: to remove of extractable water from the tissue. It was achieved by placing the tissues in ascending grades of alcohol i.e. 50%, 60%, 75%, 80%, 90% and two changes of absolute alcohol, followed by clearing using xylene to remove alcohol, followed by impregnation involved passing the tissues through molten paraffin wax in order to remove xylene, the next step was embedding which was carried out using a wax dispenser. Vertical and horizontal sections were cut using the rotary microtome (5 mm). The last stage was staining and this was achieved by the haematoxylin/eosin (H/E) staining technique. Each sample was observed under light microscopy (Olympus BH-2 microscope) connected to a performed computer. A software known as Cell Sens Dimension within the computer provided images for a further analysis and each image was captured using a digital camera. Five images are taken from each slide. Each image corresponded to a slide viewed using an objective lens of 20x magnification for tissues structure overview and 40x magnification for a detailed tissues structures. An immersion oil was used for 100x magnification that allowed an easy detection of organelles.

The image analysis consisted of comparing tissues structures of liver, muscles and gills that were exposed to pollution with those tissues belonging to the unpolluted area. The objective of this analysis was to identify any histopathological alterations in the tissues.



A photograph of the microscopic liver tissue for L. harak and T. jarbua, which collected from the studied area were represented in figures (3-6a,b).

Varieties of histological alterations were identified in the liver tissue of L. harak and T. jarbua, these alterations included vacuolated hepatocytes, fatty change, adipocytes, vacuolated foci, inflammatory response, degeneration of hepatocytes, sinusoidal dilation and frank necrosis were noted in fish specimen collected from Al-Kumrah site as shown in figures (5a,b-6a,b).

The hepatic specimen revealed hyperplastic biliary epithelium cholestasis, periductal fibrosis and edema in some portal areas accompanied by focal necrotic areas.

Other hepatic tissue exhibited acute cell swelling or steatosis in the majority of the hepatic cells together with focal interstitial lymphocytic aggregations.

Sometimes, the hepatic sinusoids and blood vessels were dilated with the presence of telangectiasis and numerous melanomacrophages centers were seen scattered among of generated hepatic cells. Hepatopancreas acinus cells were inactive side presence of dilated blood vessels. Other portal areas contained mononuclear cells and fibro blast with probabilities to in vade the adjacent interlobular hepatic tissues.

Pyknosis and karyorrhexis of the nuclei are seen, the pancreatic acinus was degenerated, and the swelling of central vein which has caused happens blood lake.

Huge of kupffer cell by inflammations, chromatin collected behind nucleolus envelope and shrinkage. Liver showing focal hemorrhage, Dark brown pigments are noticed.

The liver tissue exhibited the most histologically alterations than any other selected target organs. Structural changes were identified only in fish samples collected from Al-Kumrah site.


A photograph of the microscopic gill tissue for L. harak and T. jarbua which collected from the studied area. A variety of histological alterations were identified in the gill tissue of L. harak and T. jarbua, these alterations included necrosis, epithelial lifting, telangiectasia, the proliferation of chloride cells, crash or disappears of primary lamellae, fusion and irregulation of secondary lamellae and hyperplasia of epithelial cells and these structural changes were identified in fish samples collected from Al-Kumrah site.


A photograph of the microscopic muscle tissue for L. harak and T. jarbua which collected from the studied area was represented in fig. (11-14). Varieties of histological alterations were identified in the muscle tissue of L. harak and T. jarbua, these alterations included hyaline degeneration represented by swollen muscle fibers, the longitudinal section lack both cross and longitudinal striations, disappear intermediate disk and nucleus a lot of spaces between fiber, the bulge in connective tissue in muscle fiberboard and fragmentation of muscle fibers, these structural changes were noted and identified in the fish specimen collected from Al-Kumrah site.


In the current study regressive changes, inflammatory changes and focal cellular alterations were identified. The histological responses in the liver were mostly associated with regressive changes. Regressive changes included vacuolation, fatty change, necrosis and intracellular deposits.

Vacuolated hepatocytes are associated with the inhibition of protein synthesis, energy, depletion, disaggregation in microtubule or shift in substrate utilization (Hinton and Lauren, 1990). This alteration along with fatty degeneration was observed in both fish species collected from Al-Kumrah site in this study. Vacoulation as well as fatty change, have been reported in previous studies (Muthukumaravel and Rajaraman, 2013; Chamarthi et al., 2014; Van Dyk et al., 2009).

Inflammatory responses were mainly noted in the fish specimen from Al-Kumrah site.

Necrosis as stated by Roberts, (1989) is where cellular damage is not immediately lethal and the changes are often reversible when the source of damage is removed. Necrotic changes, as well as Pyknosis and Karyorrhexis, have been reported in previous studies (Radhakrishnan and Hemalatha, 2010; Adams et al., 2010).

Degeneration of hepatocytes and sinusoidal dilation alterations were identified in both fish species collected from Al-Kumrah site in the study. Atamanalp et al. (2008) and Velmurugan et al. (2007) have previously reported the occurrence of this alteration.

Melanomacrophages alterations were identified in both fish species collected from Al-Kumrah site in the study. Marchand et al. (2009) have previously reported the occurrence of this alteration.

Generally, L. harak and T. jarbua specimens from the Al-Kumrah site showed a higher liver alteration occurrence than Al-Shoaibah site. Macroscopic observations support these findings as several liver abnormalities were observed in Al-Kumrah area.

The gills are sensitive indicators of environmental stress, including exposure to harmful compounds present in aquatic ecosystems because of anthropogenic activities (Hinton et al., 1992). The gills in fish are vulnerable to toxicants and irritants because they are in direct contact with the surrounding water and have a rich blood supply to pick up oxygen for respiration from the water (Roberts, 2001). Therefore, functional impairment of gills caused by pollutants can jeopardize the health status of the fish.

In the current study, histological alterations in varying degrees were identified in gill. These were mostly focal circulatory disturbances and progressive changes. Circulatory disturbances are related to pathological conditions of blood and tissue fluid flow. Epithelial lifting in focal areas was noted in both fish species collected from Al-Kumrah site in the study. Epithelial lifting is characterized by the detachment of epithelial cells due to the outflow of serous fluids into the interstices of gill tissue (Van Dyk et al., 2009). This alteration has been observed in various other studies (Schmidt et al., 1999; Fanta et al., 2003; Monteiro et al., 2008 and Boran et al., 2010).

Telangiectasis of the secondary lamellae was noted in both (L. harak and T jarbua) fish species collected from Al-Kumrah site. This appearance of the secondary lamellae results from a collapse of the pillar cell system and the breakdown of vascular integrity with a release of large quantities of blood that pushes the lamellae epithelium outward (Alazemi, et al., 1996). Telangiectasia has been reported in some fishes in polluted system or under exposed conditions (Saenphet et al., 2009 and Van Dyk et al., 2009).

Progressive changes identified in the study included hyperplasia of mucous and epithelial cells. Cengiz (2006) stated that gill hyperplasia might serve as a defensive mechanism leading to a decrease in the respiratory surface and increase in the toxicant-blood diffusion distance. This defense mechanism takes place at the expense of the respiratory efficiency of the gills and eventually, the respiratory impairment must outweigh any protective effect against pollution uptake. Van Dyk et al. (2009) identified mucous hyperplasia in fish from a polluted stream while hyperplasia of the epithelium has been reported by several authors (Benli et al., 2008; Camargo and Martinez, 2007 and Boran et al, 2010).

Structural alterations in the form of lamellar fusion were also identified. This alteration has previously been identified in fish (Boran et al., 2010; Benli et al., 2008 and Chamarthi et al., 2014) and polluted streams (Van Dyk et al., 2009).

Proliferation and bulge of chloride cells were only identified in the L. harak. Pantung et al. (2008) and Chezhian et al. (2009) observed this phenomenon following exposure to cadmium and chemical factory effluent respectively.

On the basis of literature, these alterations could be related to exposure to various chemicals and poor water quality. However, these alterations could also be understood as a form of defensive mechanism against exposure to pollutants rather than as irreversible toxic effects.

Generally, L. harak and T. jarbua specimens collected from Al-Kumrah site showed a higher gill alteration occurrence than Al-Shoaibah site. Macroscopic observations support these findings as several gill abnormalities were observed in Al-Kumrah area.

The alterations in muscle has previously been identified in fish exposed to different pollutants by several authors (Fatma, 2009; Abbas and Ali, 2007; Sia Su et al. 2013 and Ramesh and Nagarajan, 2013)

Generally, L. harak and T. jarbua specimens collected from Al-Kumrah site showed a higher muscle alteration occurrence than Al-Shoaibah site. Macroscopic observations support these findings as several muscle abnormalities were observed in Al-Kumrah area.


(1.) Abbas, H. and Ali, F., Study the effect of hexavalent chromium on some biochemical, cytological and histopathological aspects of Oreochromis spp fish. Pak. J. Biol. Sci. 2007; 10: 3973-3982.

(2.) Abdel-Moneim, A. M.; Al-Kahtani, M. A. and Dlmenshawy, O. M., Histopathological biomarkers in gills and liver of Oreochromis niloticus from polluted wetland environments, Saudi Arabia. Chemosphere, 2012; 88: 1028-1035.

(3.) Abdelrahim, A.; Ali, Elhadi.; Elazein, M. and Mohamed, A., Determination of Heavy Metals in Four Common Fish, Water and Sediment Collected from Red Sea at Jeddah Isalmic Port Coast. J. Appl. Environ. Biol. Sci., 2011; 1(10): 453-459.

(4.) Adams, D. H.; Sonne, C.; Basu, N.; Dietz, R.; Nam, D-H.; Leifsson, P. S. and Jensen, A. L., Mercury contamination in spotted seatrout, Cynoscion nebulosis: an assessment of liver, kidney, blood, and nervous system health' Science of the Total Environment., 2010; 408(23): 5808-5816.

(5.) Al-Akel, A. S. and Shamsi, M. J. K., Comparative study of toxicity of carbaryl and its impact on the behavior and carbohydrate metabolism of cichlid fish, Oreochromis njloticus and catfish Clarias gariepinus from Saudi Arabia. Egypt J. Aquat Biol A Fisk., 2000; 4(2):211-227.

(6.) Alazemi, B. M.; Lewis, J. W. and Andrews, E. Gill damage in the freshwater fish Gnathonemus petersii (family: Mormyridae) exposed to selected pollutants: an ultrastructural study. Environ. Technol., 1996; 17(3): 225-238.

(7.) Al-Farawati, R., Environmental conditions of the coastal waters of Southern Corinche, Jeddah, Eastern red sea: Physico-chemical approach. Aust. J. Basic Applied Sci., 2010; 4: 3324-3337.

(8.) Atamanalp, M.; Sisman, T.; Geyikoglu. and Topal, A., The Histopathological Effects of Copper Sulphate on Rainbow Trout Liver (Oncorhynchus mykiss). Journal of Fisheries and Aquatic Science, 2008; 3: 291-297.

(9.) Au, D.W.T., The application of histocytopathological biomarkers in marine pollution monitoring: a review, Marine Pollution Bulletin, 2004; 48: 817-834.

(10.) Basaham, A.S., Distribution and behavior of some heavy metals in the surface sediments of Al-Arbaeen lagoon, Jeddah, Red Sea coast. UJ. KAU: Earth. Sci.U, 1998; 10: 59-71.

(11.) Benli, A.; Koksal, G. and Ozkul, A., Sublethal ammonia exposure of Nile tilapia (Oreochromis niloticus): Effects on gill, liver and kidney histology. Chemosphere, 2008; 72: 1355-1358.

(12.) Bin-Dohaish, E.; Abdel-Aziz, E. and EL-Ghazaly, N., The Toxic Effect of Pollutants in the Aquatic Environment on the Kidney and Blood Picture of Rabbit Fish Siganus rivulatus (Forsskal) from the Red Sea, Jeddah, Saudi Arabia., JKAU;Mar Sci., 2004; 15: 3-22.

(13.) Boran, H.; Capkin, E.; Altinok, I. and Terzi, E. Assessment of acute toxicity and histopathology of the fungicide captan in rainbow trout Experimental and Toxicologic Pathology 2010; 64 (3): 175-179.

(14.) Camargo, M. M. P. and Martinez, C. B. R., Histopathology of gills, kidney and liver of a Neotropical fish caged in an urban stream. Neotropical Ichthyology, 2007; 5(3):327-336.

(15.) Cengiz, E. I., Gill and kidney histopathology in freshwater fish Cyprinus carpio after acute exposure to deltamethrin. Environ. Toxicol. Pharm., 2006; 22: 200-204.

(16.) Chamarthi, R. R.; Bangeppagari, M.; Gooty, J. M.; Mandala, S.; Tirado, J. O. and Marigoudar, S. R., Histopathological alterations in the gill, liver and brain of cyprinus carpio on exposure to quinalphos American Journal of Life Sciences 2014; 2(4): 211-216.

(17.) Chezhian, A.; Kabilan, N.; and Kumar, S., Impact of chemical factory effluent on the structural changes in gills of freshwater fish Cyprinus carpio var communis (Linnaeus, 1758). Journal of Basic and Applied Biology, 2009; 3(1&2):28-35.

(18.) El-Rayis, O. A., Distribution of some heavy metals in sediments, water and different trophic levels from Jeddah coast, red sea. J. King Abdul Aziz Univ. Mar. Sci, 1990; 3: 33-45.

(19.) El-Sayed, M. A., Distribution and behavior of the dissolved species of nitrogen and phosphorus in two coastal Red Sea lagoons receiving domestic sewage. J. King Abdul Aziz Univ. Mar. Sci., 2002; 13: 47-73.

(20.) El-Sayed, M. A. and. Niaz, G., Study of sewage pollution profile along the Southern Coast of Jeddah: Study of some organic and inorganic pollutants. Report, KAU, SRC, 1999; 111.

(21.) Fanta, E.; Rios, F. S. A.; Romao, S.; Vianna, A. C. C. and Freiberger, S., Histopathology of the Fish Corydoras paleatus Contaminated with Sublethal Levels of Organophosphorus in Water and Food, Ecotoxicology and environmental safety, 2003; 54(2): 119-130.

(22.) Fatma, A. S. M., Histopathological studies on Tilapia zillii and Solea vulgaris from Lake Qarum, Egypt. World J. Fish. Mari. Sci. 2009; 1(1): 29-39.

(23.) Hinton, D. E. and Lauren, J. L., Integrative histopathological approaches to detecting effects of environmental stressors on fishes. Am. Fish. Soc. 1990; 8:51-66.

(24.) Hinton, D. E.; Baumann, P. C.; Gardner, G. R.; Hawkins, W. E.; Hendricks, J. D.; Murchelano, R. A. and Okihiro, M. S., Histopathologic biomarker. In Biomarkers: Biochemical, Physiological and Histological markers of Anthropogenic Stress. Edited by Huggett, R. J., Kimerle, R.A., Mehrle J. r, and P.M. and Bergman, H.L. Lewis publishers, 1992.

(25.) Mabika, N. and Barson, M., A Surey of Gill Histopathology of Thirteen Common Fish Species in the Sanyati basin, Lake Karabia, Zimbabwe. Zoologica Poloniae., 2014; 59(1-4): 25-34.

(26.) Magram, S. F., A review on the environmental issues in Jeddah, Saudi Arabia with special focus on water pollution. J. Environ. Sci. Technol., 2009; 2: 120-132.

(27.) Marchand, M. J.; van Dyk, J. C.; Pieterse, G. M.; Barnhoorn, I. E. J. and Bornman, M. S., Histopathological alterations in the liver of the sharptooth catfish Clarias gariepinus from polluted aquatic systems in Environ. Toxicol, 2009; 24: 133-147.

(28.) Monteiro, S. M.; Rocha, E.; Fontainhas-Fernandes, A. and Sousa, M., Quantitative histopathology of O. niloticus gills after copper exposure. Journal of Fish Biology. 2008; 73: 1376-1392.

(29.) Muthukumaravel, K. and Rajaraman, P., Astudy of the toxicity of chromium on the histology of gill and liver of fresh water fish Labeo rohita., J. Pure Appl. Zool., 2013; 1(2): 122-126.

(30.) Pantung, N.; Helander, K. G.; Helander, H. F. and Cheevaporn, V., Histopathological alterations of hybrid walking catfish (Clarias macrocephalus x Clarius gariepinus) in acute and sub-acute cadmium exposure. Environmental Asia 2008; 1:22-27.

(31.) PERSGA (Regional Organization for the Conservation of the Environment of the Red Sea and Gulf of Aden)., State of the marine environment, Report for the red sea and Gulf of Aden. PERSGA, Jeddah, Saudi Arabia, 2006; 260; 861.

(32.) Radhakrishnan, M. V and Hemalatha, S., sublethal toxicity effects of cadmium chloride to liver of freshwater fish Channa striatus (Bloch) Am-Emuras. J. Toxicol. Sci., 2010; 2(1): 54-56.

(33.) Ramesh, F. and Nagarajan, K., Histopathological Changes in the Muscle Tissue of the Fish Clarias batrachus exposed to Untreated and Treated Sago Effluent Advances in Bioscience and Bioengineering 2013; 1(2): 74-80.

(34.) Roberts, R. J., Fish pathology. 2nd edn. London: Bailliere Tindal, 1989.

(35.) Roberts, R. J., Fish pathology. W.B. Saunders: Harcourt Publishers Ltd, 2001.

(36.) Saenphet, K.; Supap, S. and Thaworn, W., Histopathological alterations of the gills, liver and kidneys in Anabas testudineus (Bloch) fish living in an unused lignite mine LI district. Lamphun Province, Thailand Southeast Asian. J Trop Med Public Health, 2009; 40:1121-1126.

(37.) Schmidt, D. C. and Weber, L. J., Metabolism and biliary excretion of sulfobromophthalein by rainbow trout (Salmo gairdneri). J. Fish. Res. Bd. Can., 1973; 30:1301-1308.

(38.) Sia Su, G. L.; Ramos, G. B. and Sia Su, M. L. L. Bioaccumulation and histopathological alteration of total lead in selected fishes from Manila Bay, Philippines Saudi Journal of Biological Sciences 2013; 20: 353-355.

(39.) Turki, A.; El-Sayed, M. A.; Al-Farawati, R. and Basaham, A. S., Study on the distribution, dispersion and mode association of some organic and inorganic pollutants in a coastal lagoon receiving sewage disposal. Report KAU, SRC, 2002.

(40.) Van Dyk, J. C.; Marchand, M. J.; Smit, N. J. and Pieterse, G. M., A histology-based fish health assessment of four commercially and ecologically important species from the Okavango Delta panhandle, Botswana African Journal of Aquatic Science, 2009; 34(3): 273-282.

(41.) Velmurugan, B.; Selvanayagam, M.; Cengiz, E. I. and Unlu, E., Histopathology of lambda-cyhalothrin on tissues (gill, kidney, liver and intestine) of Cirrhinus mrigala. Environ Toxicol Pharmacol, 2007; 24: 286-291.

Esam O. Al-Wesabi [1,2,3] *, Osama A. Abu Zinadah [1], Talal A. Zari [1] and Zaki M. Al-Hasawi [1]

[1] Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.

[2] Center of Excellence in Environmental Studies, King Abdulaziz University, Jeddah, Saudi Arabia.

[3] Al-Hodeidah University, Republic of Yemen.

(Received: 27 May 2015; accepted: 06 August 2015)

* To whom all correspondence should be addressed. E-mail:

Table 1. The ecological characteristics and recorded
morphometric measures of examined fish species

Scientific   English, common name     Local      Feeding
Name                                   Name     habitats

L. harak     Black-spot Emperor,      Shoara    Carnivore
               Thumbprint emperor    bunoqtah
T. jarbua    Jarbua terapon,         Garboa,    Carnivore
               Thornfish, Tigerfish   makhtout

Scientific   Model of    No. of          Length
Name           life      samples          (cm)
                                    mean [+ or -] SE

L. harak      Pelagic      66      27.3 [+ or -] 1.05

T. jarbua    Epiplagic     66      27.4 [+ or -] 0.88

Scientific         Weight
Name                 (g)
              mean [+ or -] SE

L. harak     218.6 [+ or -] 4.39

T. jarbua    207.7 [+ or -] 8.23

SE: Standard Error
COPYRIGHT 2015 Oriental Scientific Publishing Company
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2015 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Wesabi, Esam O. Al-; Zinadah, Osama A. Abu; Zari, Talal A.; Hasawi, Zaki M. Al-
Publication:Journal of Pure and Applied Microbiology
Article Type:Report
Geographic Code:7SAUD
Date:Sep 1, 2015
Previous Article:Effect of weakly alkaline salt pretreatment on bio-boards for medicine safety.
Next Article:Prevalence of extended-spectrum beta-lactamase producing Enterobacteriaece from various clinical isolates in Al-ansar hospital, Medina, Saudi Arabia.

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters