Staphylococcus aureus

Staphylococcus   aureus

                                  

-Etymology :

  Staph    : Greek word Meaning “ Grape like cluster”

  Coccus : berry (spherical shape)

  aureus :  Latin word meaning “ Golden” (gives golden  yellow color colonies )    

   

- Discovery             

S. aureus was discovered by the surgeon Sir Alexander Ogston (1880), Scotland in pus from surgical abscesses 

-Habitat: Ubiquitous in nature and normal inhabitant of the skin and nose( mucous membranes ) of health persons. S. aureus is infectious to both animals and humans and may only survive on dry skin. Spread through contaminated surfaces, air and people.

                                          Morphology 

-Gram Positive Organism 

- Cocci -  O -  in shape 

- Size : 1 to 2  μm in diameter

- Non- motile

- Non- Spore forming

- Appear in single, pair and short chains

- Some are have capsule. 

                                         Cultural characteristics

-          -Grow on ordinary medium eg. nutrient agar

-        -  Growth temperature is 10 ^° C  - 42^° C

-         - Optimum temperature is 37^°C

-         - Aerobes and facultative anaerobes

-         - pH range 7.4 to 7.6

-          -Nutrient agar :   It produces Circular, smooth, Convex and opaque colonies.

-         - Blood agar :  It produces marked hemolytic (β- hemolysis) colony. (Sheep blood)

-          -Mannitol Salt agar (MSA) : It produce yellow colonies with yellow zones, whereas   other Staphylococci  produce pink or red colonies without color change of the medium

-          -Liquid medium :  Uniform turbidity

-          -Selective medium: Salt milk agar ,Salt broth

Nutrient Agar

Blood Agar

 

Mannitol Salt Agar (MSA)

Salt Milk Agar

                                                                         Biochemical Test

Catalase Test: Positive

Coagulase Test: Positive

Coagulase is an enzyme-like protein and causes plasma to clot by converting fibrinogen to fibrin in palsma. 

Carbohydrate fermentation : S. aureus ferment mostly  mannitol sugar and produce acid without gas.

                                           Pathogenicity

Infections & Diseases

Skin & Soft Tissue:  Boils, Abscess, Wound infection, Impetigo, Cellulitis, Folliculitis

Musculoskeletal:  Osteomyelitis, Arthritis, Pyomyositis

Respiratory: Tonsillitis, Pharyngitis, Sinusitis, and Bronchopneumonia

Central nervous system:  meningitis, abscess

Endovascular: Bactremia, Septcemia, Endocarditis

Urinary Tract Infection : Uncommon

TSS: Toxic Shock Syndrome (Multisystem disease) symptoms are Fever, Vomiting, Diarrhea, Rashes

SSSS: Staphylococcal Scaled Skin Syndrome is Outer layer of epidermis get separated. 

Virulence Factors

Cell surface proteins:

Protein A: Anti- phagocycotic, Anti- complimentary and damages the platelets.

                  Clumping factor: in slide test coagulate the plasma

Extra Cellular Enzymes: Lipases (Hydrolysis the lipids),

                                          Hyaluronidases (Breakdown the Hyaluronic acid present in the  

                                        tissues),

                                        Nucleases (Breakdown nucleic acid)

Toxins:      Cytolytic cytotoxins; 

                            hmolysins ,

                            Leucocidine

                   Enterotoxin: Causes Staphylococcus food poisoning

                                      Types are A, B, C_1-3, D, E & F

                                       Present in Mil products, meat etc., 

Laboratory Diagnosis

Collection of Samples:  Skin Scrapping, Pus, Food samples, Throat and nasal swabs.

Microscopic observation: Gram staining

Culture: Nutrient agar, Blood agar, Mannitol Salt agar (MSA)

Biochemical Test: Catalase Test,

                              Coagulase Tests (Slide and Tube Test)

Antibiotic Sensitivity Test  ( Kirby bauer Method ) :

            Drugs  : Penicillin,

                          Methicillin (Some strains are resistant against Methicillin are called MRSA)

                          Coaxacillin,  Bacitracin, Vancomycin, Rifampicin, Cephalosporins ,                    

                           Erythromycin, Tetracyclines  etc.

Other diagnosis methods: 

             Phage Typing: Phage typing is a method used for detecting single strains of bacteria. It is used to trace the source of outbreaks of infections. The viruses that infect bacteria are called bacteriophages.

            Molecular Typing : Using RFLP, RAPD, MLST , REP-PCR, Real time PCR 

                 MALDI-TOF:  emerging technique to identify the unkown bacteria

Fundamentals of Entrepreneurship Book PDF

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http://www.unishivaji.ac.in/uploads/distedu/SIM2013/B.%20Com.%20Part-II%20Fundamentals%20of%20Entrepreneurship%20English%20Version.pdf

Role of Entrepreneurs

1. Employment opportunities

Entrepreneurs employ labour for managing their business activities and provides employment opportunities to a large number of people. They remove unemployment problem.

2. Balanced Regional Development

Government promotes decentralized development of industries as most of the incentives are granted for establishing industries in backward and rural areas. Thus, the entrepreneurs to avail the benefits establish industries in backward and rural areas.

They remove regional disparities and bring balanced regional development. They also help to reduce the problems of congestion, slums, sanitation and pollution in cities by providing employment and income to people living in rural areas. They help in improving the standard of living of the people residing in suburban and rural areas.

3. Mobilization Of Local Resources

Entrepreneurs help to mobilize and utilize local resources like small savings and talents of relatives and friends, which might otherwise remain idle and unutilized. Thus they help in effective utilization of resources.

4. Optimization Of Capital

Entrepreneurs aim to get quick return on investment. They act as a stabilizing force by providing high output capital ratio as well as high employment capital ratio.

5. Promotion of Exports

Entrepreneurs reduce the pressure on the country’s balance of payments by exporting their goods they earn valuable foreign exchange through exports.

6. Consumer Demands

Entrepreneurs produce a wide range of products required by consumers. They meet the demand of the consumers without creating a shortage for goods.

7. Social Advantage

Entrepreneurs help in the development of the society by providing employment to people and paves for independent living They encourage democracy and self-governance. They are adept in distributing national income in more efficient and equitable manner among the various participants of the society.

8. Increase per capita income

Entrepreneurs help to increase the per capita income of the country in various ways and facilitate development of backward areas and weaker sections of the society.

9. Capital formation

A country can attain economic development only when there is more amount of investment and production. Entrepreneurs help in channelizing their savings and savings of the public to productive resources by establishing enterprises. They promote capital formation by channelizing the savings of public to productive resources.

10. Growth of capital market

Entrepreneurs raises money for running their business through shares and debentures. Trading of shares and debentures by the public with the help of financial services sector leads to capital market growth.

11. Growth of infrastructure

The infrastructure development of any country determines the economic development of a country, Entrepreneurs by establishing their enterprises in rural and backward areas influence the government to develop the infrastructure of those areas.

12. Development of Trader

Entrepreneurs play an important role in the promotion of domestic trade and foreign trade. They avail assistance from various financial institutions in the form of cash credit, trade credit, overdraft, short term loans, secured loans and unsecured loans and lead to the development of the trade in the country.

13. Economic Integration

Entrepreneur reduces the concentration of power in a few hands by creating employment opportunities and through equitable distribution of income. Entrepreneurs promote economic integration in the country by adopting certain economic policies and laws framed by the government. They help in removing the disparity between the rich and the poor by adopting the rules and regulation framed by the government for the effective functioning of business in the country.

14. Inflow of Foreign Capital

Entrepreneurs help to attract funds from individuals and institutions residing in foreign countries for their businesses.

Concepts and Definitions of Entrepreneurship

CONCEPTS OF ENTREPRENEURSHIP : 

Various economists, sociologists and psychologists have used different approaches to explain the concept of entrepreneurship. These approaches are summarized below :

1. Economic Approach : Economists like Richard Cantillon, Adam Smith, J.B. Say, Carl Menger, Joseph Schumpeter have explained the concept of entrepreneurship from the economic point of view. According to the economic approach entrepreneurship is the process of initiating a new venture by organizing the resources required and accepting the risk involved therein. Entrepreneurship and ultimately economic development takes place when the economic condition is favourable. An entrepreneur buys the factors of production at a certain price, converts them into products and sells them at an uncertain price. Thus, economists have emphasized two main aspects, viz. innovation and risk bearing. The entrepreneurs create new things, use new technology, find new sources of raw material, source of new markets and so on. By the innovation function entrepreneurs make available new products to the people and help to raise their standard of living.

2. Sociological Approach : Sociologists have emphasized the impact of social system, ethics, values, customs, and perception on entrepreneurship. They hold that entrepreneurship flourishes in those societies, which recognize the services of entrepreneurs, respect them and give approval to the business and wealth creation. According to them entrepreneur represents society’s model personality.

3. Psychological Approach : According to the psychological approach entrepreneurship is influenced by factors like high achievement, motive, self-reliance, creativity, desire to regain the lost status. The psychological approach is developed by Macmilan and Hansen.

4. Modern Approach : The modern approach states that entrepreneurs have to function under adverse conditions. There is a scarcity of labour, shortage of capital and uncertain market. Hence they require to possess organizing skills, innovative ability, decision making ability, risk bearing capacity .

Definition of Entrepreneurship :

Let us now study select definitions of entrepreneurship

 :1. Higgins B : Entrepreneurship is the function of seeking investment and production opportunity, organizing an enterprise to undertake a new production, process, raising capital, hiring labour, arranging the supply of raw materials, finding site, introducing new techniques and commodities, discovering new sources of raw materials, and selecting top managers of day-to-day operations of the enterprise.

2. Joseph Schumpeter : Entrepreneurship essentially consists in doing things that are not generally done in the ordinary course of business routine.

3. Peter Drucker : Entrepreneurship occurs when resources are redirected to progressive opportunities not used to ensure administrative efficiency. Entrepreneurship is not natural; it is not creative. It is work. Entrepreneurship requires entrepreneurial management.

4. John Kao : Entrepreneurship is an attempt to create value through recognition of business opportunity, the management of risk taking appropriate to the opportunity and through the communicative and managerial skills to mobilize human, financial and material resources

பூஞ்சை - தாவரமா ?

பூஞ்சைகள் மற்றும் காளான்கள் தாவர குடும்பத்தைச் சேர்ந்தவையா?   

இல்லை. அவைகள் முதலில் தாவரங்களின் கீழ் வகைப்படுத்தப்பட்டிருந்தன. (மண்ணில் இருந்து வளர்வதாலும், நாம் உண்ணும் காளான்கள் தாவரங்களைப் போலிருப்பதாலும்). இப்போது பூஞ்சை விலங்குகள் மற்றும் தாவரங்களுக்கு இணையான தனிக் குடும்பமாக (kingdom) இருக்கிறது. 

பூஞ்சைகக்காளான்களின் பெரும்பாலான குணங்கள் விலங்குகளையே ஒத்திருக்கிறது.  பூஞ்சைகளின் செல் சுவர் (cell wall) கைட்டின் (chitin) எனப்படும் பொருளால் ஆனது. இந்த கைட்டின் சில வகை பூச்சிகள் மற்றும் நண்டுகளின் ஓடு போன்றவற்றிலுள்ளது. தாவரகளின் செல் சுவர் செல்லுலோஸால் (cellulose) ஆனது. பூஞ்சைகள்  கிளைகோஜென் எனப்படும் பொருளை சேமித்து வைத்துப் பயன்படுத்துகிறது. இக்கிளைகோஜெனை உபயோகிக்கும் வழக்கம் தாவரங்களில் இல்லை.

குளோரோஃபில் (chlorophyll) என்னும் தாவரங்களில் காணப்படும் பச்சைய நிறமிகள்  பூஞ்சைகளில் இருப்பதில்லை. பூசணம் என்றழைக்கபடும் இப்பூஞ்சைகள் உணவுகளைத் தானே தயாரிக்காமல், பிற உயிரினங்களிலிருந்து நொதிகளின் உதவியுடன் உறிஞ்சி எடுத்துக் கொள்கிறது, எனவே இவை சார்பூட்ட உயிரிகள் (heterotrophs) என அழைக்கப்படுகிறது.

     பூஞ்சைகளைப் பற்றிய படிப்பிற்க்கு மைக்காலஜி (mycology) என்று பெயர்.

Centrifugation PPT

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PAPER CHROMATOGRAPHY

Aim:

To separate and identify the amino acids in mixture by Paper chromatography

Introduction:

Chromatography is a physicochemical method for separation of complex mixtures and was discovered in 1903 by Russian-Italian botanist M. S. Tswett. It is the most powerful technique to separate and identify the substances in to the individual from the mixture based on their physicochemical properties. The compounds are separated on the basis of their partition coefficient between two immiscible phases.  The stationary phase is may be a solid or liquid, mobile phase is may be a solid, liquid or gas.

In paper chromatography the solutes applied to a piece of filter paper, the edge of the paper is immersed in a solvent, and the solvent moves up the paper by capillary action. Components of the mixture are carried along with the solvent up the paper to varying degrees, depending on the compound's preference to be adsorbed onto the paper versus being carried along with the solvent. The paper is composed of cellulose to which polar water molecules are adsorbed, while the solvent is less polar, usually consisting of a mixture of water and an organic liquid. The paper is called the stationary phase while the solvent is referred to as the mobile phase. Performing a chromatographic experiment is basically a three-step process: 1) application of the sample, 2) "developing" the chromatogram by allowing the mobile phase to move up the paper, and 3) calculating Rf values and making conclusions. In order to obtain a measure of the extent of movement of a component in a paper chromatography experiment, we can calculate an "Rf value" for each separated component in the developed chromatogram. An Rf value is a number that is defined as:

Materials Required:

Amino acid solution (2% each)

Solvent mixture of  n- butanol, acetic acid and water in the ratio 4:1:5 by volume.

Ninhydrin reagent.

Chromatography chamber

Micro syringe or capillary tube

Ninhydrin sprayer/ Atomiser

Procedure:

1. Whatman filter paper was cut into a rectangular piece of desired measurement.

2. A line of origin was marked approximately 2 cm from the bottom.

3. The given amino acid samples were placed as spots on the line of origin.

4. The paper was placed in a tank/chamber containing the solvent n butanol, acetic acid and  

     water.

5. The setup was left undisturbed for capillary action to draw the solvent up the paper until it is   

    approximately 1 cm from   the end.

5. After this process removed the paper and immediately drawn a pencil line across the solvent   

    top and allowed  the paper to dry.

6. Sprayed the locating reagent ninhydrin and dried the paper in oven at 105°C for 5 min.

7. Spots were located and the Rf value was determined using the formula.

Result:

The given amino acids were identified as ______   based on Rf value and results were tabulated.