Other Innovations

Recent improvements in the scanning tunneling and atomic force microscopes have enhanced their capabilities. Using a fluid cell (a specially designed container that keeps a wet or liquid sample from drying out and maintains its level of acidity or alkalinity and its salinity), for example, opens the way to techniques not otherwise possible.

New types of atomic force microscopes include the so-called lateral-force AFM, which can determine which areas on a surface are softer than others indicating a more pronounced effect of a chemical reaction.

Another remarkable new instrument is the photon tunneling microscope, developed in the late 1980s. This is a light microscope, but it can achieve better resolution than conventional optical microscopes. Under certain conditions photons ("particles" of light) will "tunnel" from the sample to an optical window on the microscope when the gap between the two is smaller than the wavelength of the light used. The resulting video image is converted into a real-time three-dimensional image of the sample's surface.

About the author: Samuel H. Cohen, a member of the Microscope Society of America and a fellow of the Royal Microscopical Society, is a research physical scientist for the U.S. Army Natick Research, Development, and Engineering Center in Natick, MA.

Source: 1994 Collier’s Year Book.

Task9. Cover the information from the previous text once more and fill in the table.

Type of microscope

The principle of work

Advantages

Task10. Answer the question: if you had such an opportunity what microscope would you prefer to use? Why? Explain the choice.

Task11. Find English equivalents to the following Russian word combinations, transcribe them and memorize.

жидкая среда

сложное вещество

вид бактерий

видимые колонии бактерий

отличаться друг от друга

конечный продукт ферментации

широко используемый метод

грамм-положительные (грамм-отрицательные) бактерии

точно сфокусированный пучок электронов

отражаться от поверхности

проводить электричество

в определенных условиях

GRAMMAR SECTION

Task1. Make up sentences out of these words.

1. Visible colonies / bacteria / to compose of / millions of cells / to derive / binary fission.

2. Various cultural technique / to develop / to aid / species identification.

3. Sufficient gas production / to result / the formation / bubbles / easily / to see.

4. Second electrons / to pick up / a detector / to convert / an image / to display / a TV monitor.

Task2. These are answers. Make up questions.

1. The formation in the agar of bubbles.

2. It consists of 1 part iodine, 2 parts potassium iodide, and 300 parts water.

3. To make bacteria more visible.

4. The bacilli that cause tuberculosis.

5. Optical sectioning can be performed in living biological samples without introducing chemicals.

Task3. Imagine you did not hear the beginning of the sentence. Ask your fellow-student; begin your questions with who or what.

1. Typical gram-positive bacteria are those staphylococci that produce boils.

2. Optical microscopes generally cannot resolve objects smaller than one-half the wavelength of the light they employ.

3. Media contain nutrients, varying from simple sugars to complex substances such as meat broth.

4. A compound microscope consists of an eyepiece (technically known as an ocular) and a second lens (called an objective).

5. Some of the most remarkable new microscopes can produce images of the atoms or molecules on the surface of things.

Task4. There is a mistake in each of these sentences. Find it and correct.

1. Various culture techniques has been developed to aid in species identification.

2. The photon tunnel microscope is a remarkable new instrument.

3. A new tool calling the confocal microscope is able to produce thin sections optically.

4. After washing with ethyl alcohol, the bacteria will either retain the strong blue color of gentian violet or be completely decolorized.

5. Solidified media generally are used purifying or isolating a single bacterial species from a mixture of different bacteria.

Task5. Fill in necessary prepositions.

1. Individual cells dividing … the surface … solidified media do not move away … each other as they do … liquid.

2. … being washed … ethyl alcohol, the bacteria will either retain the strong blue color … gentian violet or be completely decolorized.

3. … the new "scanning laser acoustic" instrument researchers were able to obtain images … … samples as thick as 1 inch.

4. … certain conditions photons ("particles" of light) will "tunnel" … the sample … an optical window … the microscope.

5. … transmission electron microscopes an electron beam passes … a thin sample.

6. The ultrasound may be reflected … the sample's surface or transmitted … the sample.

Task6. Make these questions less direct.

1. What does a conventional microscope consist of?

e.g. Can you tell me what a conventional microscope consists of?

2. What is the advantage of newly invented microscopes?

3. What methods are used as an aid to bacterial identification?

4. How can the end product of fermentation be detected?

5. How many types of electron microscopes do you know?

6. What phenomenon do physicists call electron tunneling?

Task7. Answer your partner’s questions from the previous exercise.

Task8. Render the following text into Russian.

Понимание структуры вещества всегда было заветной целью естествоиспытателей. Ученые тем или иным способом пытались выяснить структуру атомного ядра и полупроводников, ДНК и живой клетки. И когда им удавалось понять, «что у зайчика внутри» и какие микроскопические закономерности управляют макроскопическими свойствами, происходили прорывы в технологиях, открывались богатые источники энергии, рождались новые отрасли производства, появлялись удивительные приборы. Оптический и электронный микроскопы, рентгеновские аппараты, спектрографы, компьютерные томографы, сканирующие туннельные и атомно-силовые микроскопы – это лишь часть инструментальных вех, оставленных учеными и инженерами на пути в глубины мира.

Световые волны, рентгеновские лучи и пучки электронов идеально подходят на роль исследователей структуры вещества; однако эти методы зондирования, как правило, работают с группой атомов и позволяют понять её структуру только при наличии большого упорядоченного куска кристаллической решётки. Революция в изучении атомарной структуры поверхности началась с изобретением сканирующего туннельного микроскопа, использующего эффект туннелирования, или прохождения объекта сквозь стену без её разрушения. Однако вскоре стало понятно, что это не единственный способ увидеть атомы.

Следующим этапом оказалось создание атомно-силового микроскопа, способного чувствовать силы притяжения и отталкивания, существующие между отдельными атомами. Самым новым изобретением является сканирующий зондовый микроскоп, позволяющий не только видеть и трогать отдельные атомы, но и перемещать их с одного места на другое по одному.

UNIT 3.

CURRENT RESEARCH  IN MICROBIOLOGY

Task1. Read and translate the text about recent studies in bacteriology.

In recent years, bacteriology has been greatly expanded from its concentration on bacterial disease. The discovery that bacteria fix nitrogen in the root nodules of leguminous plants has led to attempts to inoculate the roots of other plant strains and thereby increase soil fertility and the productivity of food crops. Some bacteria are able to digest petroleum and other hydrocarbons; others absorb phosphorus. These bacteria are being intensively investigated as possible aids in cleaning up oil spills and removing phosphorus from sewage sludge. Other bacteria may be more efficient than yeast at producing alcohol and are being explored in the search for new energy sources. Escherichia coli, a normal inhabitant of the human intestinal tract, is the most thoroughly studied of all organisms. Studies of the mechanisms of genetic exchange and the biology of plasmids and bacteriophages of E. coli have been crucial in understanding many aspects of DNA replication and the expression of genetic material. These studies have led to the ability to insert DNA from unrelated organisms into E. coli plasmids and bacteriophages and to have that DNA replicated by the bacteria, with the genetic information it contains expressed by the bacteria. It is thus possible for bacteria to become living factories for scarce biological products such as human insulin, interferon, and growth hormone.

In 1977 scientists successfully manipulated bacteria to produce a human protein. The same year American molecular biologist Walter Gilbert found a way to accelerate dramatically the laborious task of sequencing the chemicals that make up a strand of genetic material. He shared the 1980 Nobel Prize in chemistry for this achievement. In a 1980 Scientific American article, Gilbert and American molecular biologist Lydia Villa-Komaroff described basic biotechnology techniques and their laboratory’s success in producing rat insulin with genetically engineered bacteria. Human insulin was first produced in the lab using recombinant (genetically engineered) bacteria in 1978, and five years later recombinant human insulin, used to treat diabetes mellitus, became the first biopharmaceutical on the market.