In Vitro Antibacterial Effect of Traditional Chinese Medicine on Main Pathogenic Bacteria of Recessive Mastitis in Dairy Cows

The inhibition zone diameter, minimal inhibitory concentration （MIC） and minimum bactericidal concentration （MBC） of 20 kinds of traditional Chi- nese medicine on Staphylococcus aureus and Streptococcus agalactiae isolated from recessive mastitis were studied using plate test and tube test. The results showed that S. aureus and S. agalactiae were sensitive to all these 20 kinds of traditional Chinese medicine, and were more sensitive to seven kinds of traditional Chinese medicine, including Taraxtwum mongolicum, Coptis chinensis, Forsythia suspense, Andrographis paniculata, Carthamus tinctorius, Scutellaria baicalensis and Den- dranthema indicum.

In vitro assessment of the synergism between extracts of Cocos nucifera husk and some standard antibiotics

Objective: To evaluate the interactions between the crude extracts of Cocos nucifera(C.nucifera) and six front line antibiotics(ampicillin sodium salt, penicillin G sodium,amoxicillin, chloramphenicol, ciprofloxacin and tetracycline hydrochloride), against some bacterial pathogens linked with human infection.Methods: The pulverized husk of C.nucifera was dissolved in 95% n-hexane and extracted using Soxhlet extraction method and sterile distilled water(aqueous).The antibacterial susceptibility of the crude extracts of C.nucifera was tested against environmental and clinical strains(6) obtained from the South African Bureau of Standards(SABS), Vibrio(6) and Listeria pathogens(6).The agar-well diffusion method was used for screening the extracts for their antibacterial activity.The minimum inhibitory concentration and minimum bactericidal concentration of the extracts were determined.Time-kill assay was used to evaluate bactericidal and/or bacteriostatic activity.The synergistic effect of the crude extracts and antibiotics was assessed and evaluated by adopting the checkerboard methods.Results: With the time-kill assay, the highest bactericidal activity was observed on Vibrio fluvialis EL041 with a-5.6 ± 0.2 log_(10)CFU/mL decrease in cell density as a result of the combination of the extracts and chloramphenicol at two-fold minimum inhibitory concentrations.Synergisms using the time-kill assay constituted about 72%, while indifference constituted about 28%.The checkerboard method revealed synergistic interaction in 67% of the combinations, and indifference in 33%.There was no specificity in the observed synergy to a particular class of antibiotics.Conclusions: This investigation suggests the crude extracts of C.nucifera to be a potential broad spectrum antimicrobial compound.Therefore, further study is needed to isolate the pure compounds from these crude extracts.

Antimicrobial Activity of Purified Toxins from Yellow Wasp Polistes flavus (Vespidae) against Certain Bacteria and Fungi

Yellow Wasp Polistes flavus venom toxins were isolated and purified on a Sepharose CL-6B 200 column. Purified proteins were investigated for its antibacterial and antifungal activity against 13 infectious microbial pathogens. Paper disc diffusion and serial micro-dilution assays were performed for the determination of inhibition zone (DIZ) diameters and minimal inhibitory concentration, respectively. Triton X-100 (0.1%) proved to be a good solubilizing agent for toxin/proteins. Higher protein solubilization was observed in the supernatant than in the residue, except TCA (tri-chloroacetic acid). The elution pattern of purified and homogenized sting glands exhibited two major peaks at 280 nm in fraction No. 41 - 61 and 81 - 101. The total yield of protein was 69.21% and specific activity was determined in each fraction. Molecular weights in protein fractions were ranging from 6 - 70 kD. MIC (Minimum Inhibitory Concentration) values were 12.3 μg/ml against K. pneumonia 12.3 μg/ml against E. coli and L. acidophilus, 24.6 μg/ml against B. cereus;49.24 μg/ml against S. aureus and M. luteus. By agar disc diffusion method, the diameter of inhibition zones in mm in presence of yellow wasp toxins is at a concentration range of 98.56 - 6.9 μg/ml E. coli 18.36 ± 0.14, Bacillus cereus 14.566 ± 0.21, L. acidophilus 18.10 ± 0.21, Micrococcus luteus 18.76 ± 0.19, S. aeurus 17.36 ± 0.43, Klebsiella pneuminiae 19.56 ± 0.21, Salmonella typhi 19.96 ± 0.31, Vibrio cholera 21.83 ± 0.22, Pseudomonas aeruginosa 22.90 ± 0.09, Aspergillus niger 21.66 ± 0.16, Candida albicans 23.33 ± 0.26, Rhizopus stolonifer 24.96 ± 0.16 respectively. The antibacterial and antifungal activity of venom toxin may be due to action on cell membrane, its destruction and cell lysis. The wasp toxins may be used as strong biological agents to control microbes.

Medicinal Plants, A promising Source of Natural Fungicides against <i>Magnaporthe oryzae Triticum</i>, Causal Agent of Wheat Blast

Wheat blast, caused by a fungal pathogen, Magnaporthe oryzae Tritichum (MoT) pathotype (wheat isolates), was first reported in Bangladesh among Asian countries in 2016. It is a serious disease of wheat causing yield failures and significant economic losses during epidemic years. Extensive use of persistent synthetic pesticides to control notorious wheat blast imposes enormous threat to human health and environment. In addition, the increasing demand for organic food has stimulated people to look for alternative methods. Nowadays, the need for synthetic chemical-free agricultural practices is gaining importance due to effective in managing crop pests, inexpensive, biodegradable, easily available and have low toxicity to non-target organisms. In order to identify active plants, 12 kinds of methanol extracts obtained from 12 medicinal plants were conducted in vitro to test the effect against Magnaporthe oryzae Triticum (MoT) pathotype. The remarkable inhibitory activity {(29.6 ± 01.5) mm, (25.1 ± 01.0) mm and (20.0 ± 02.0) mm zone of inhibition)} exhibited by the extracts (5 mg/disk) obtained from Artemisia indica (Nagdona), Persicaria orientalis (Bishkatali) and Clerodendrum indicum (Bamonhati), respectively. Other medicinal plant extracts did not show any significant or no activity at all. Therefore, the three plant extracts might be a promising source for developing natural fungicides against wheat blast.

Biology of tooth replacement in amniotes

Tooth replacement is a common trait to most vertebrates, including mammals. Mammals, however, have lost the capacity for continuous tooth renewal seen in most other vertebrates, and typically have only 1-2 generations of teeth. Here, we review the mechanisms of tooth replacement in reptiles and mammals, and discuss in detail the current and historical theories on control of timing and pattern of tooth replacement and development.

Assessment of bactericidal role of epidermal mucus of Heteropneustes fossilis and Clarias batrachus (Asian cat fishes) against pathogenic microbial strains

This research was directed to understand the bactericidal effect of epidermal mucus of two Asian cat fish species viz.Clarias batrachus and Heteropneustes fossilis.Epidermal mucus extracts(raw and diluted)of both cat fish species were tested against several Gram negative(Pseudomonas aeruginosa,Escherichia coli,Klebsiella pneumonia,A.hydrophila)and Gram positive bacterial strains(Bacillius cereus,Staphylococcus aureus,S.epidermidis)and antibacterial results were also compared with two standard antibiotics viz.amikacin and chloramphenicol used as positive control.An A.hydrophila challenge experiment was also performed on all selected test fish species to examine the change in the amount of mucus production and its bactericidal impact..Both epidermal mucus extracts(raw and diluted)of all selected normal and bacterial challenged test objects showed potent bactericidal effect against all pathogenic bacterial strains taken under study.However,former was more effective than later.Also raw epidermal mucus extracts of both normal and bacterial challenged cat fish species exhibited significantly higher ZOI values against all selected microbial strains than diluted mucus extracts and antibiotic chloramphenicol.Hence,these outcomes have clearly revealed that this cost effective natural product acquired from fishes is the key component of their defensive system.Therefore,it could be utilized as a novel‘antimicrobial’in human as well as veterinary sector for combating against several bacterial diseases.

A green synthesis of antimicrobial compounds from marine microalgae Nannochloropsis oculata

Objective:To determine the antibacterial and anti-candidal activities of fatty acid methyl esters(FAME)extracted from marine microalga Nannochloropsis oculata and evaluate the inhibition activity of DNA isolated from test pathogenic microorganism.Methods:FAME was synthesized by transesterification of oil using immobilized lipase and characterized using gas chromatography-mass spectrometer.The FAME profile was determined using gas chromatography.The antimicrobial effect was tested by disc diffusion method against Gram-positive bacteria Staphylococcus aureus,Bacillus subtilis,Gram-negative bacteria Escherichia coli,Pseudomonas aeruginosa and yeast Candida albicans,at varying concentrations of 10,20 and 30μL/disc.Results:The results shown that palmitic acid(C16:0),oleic acid(C18:1)and arachidic acid(C20:0)were dominant in Nannochloropsis oculata oil.The study revealed that FAME was more active against Gram-negative than against Gram-positive and yeast.DNA inhibition activity results also confirmed that FAME had the bactericidal effect that was revealed by sheared fragments of DNA.Conclusions:The results indicated that microalgal FAME could be potentially utilized as a newer and good source of therapeutic agent in pharmaceutical industry.