Eukaryotic Cells Have Complex Interiors

Eukaryotic cells (figures below)

are far more complex than prokaryotic cells.The hallmark of the eukaryotic cell is compartmentalization. The interiors of eukaryotic cells contain numerous organelles, membrane-bounded structures that close off compartments within which multiple biochemical processes can proceed simultaneously and independently.Plant cells often have a large membrane-bounded sac called a central vacuole, which stores proteins, pigments,and waste materials. Both plant and animal cells contain vesicles, smaller sacs that store and transport a variety of materials.Inside the nucleus, the DNA is wound tightly around proteins and packaged into compact units called chromosomes. All eukaryotic cells are supported by an internal protein scaffold, the cytoskeleton. While the cells of animals and some protists lack cell walls, the cells of fungi, plants, and many protists have strong cell walls composed of cellulose or chitin fibers embedded in a matrix of other polysaccharides and proteins. This composition is very different from the peptidoglycan that makes up bacterial cell walls. Let’s now examine the structure
and function of the internal components of eukaryotic cells in more detail.

Eukaryotic cells contain membrane-bounded organelles that carry out specialized functions.

Structure of a plant cell. A generalized illustration of a plant cell. Most mature plant cells contain large central vacuoles which occupy a major portion of the internal volume of the cell (14,000 ).

Bacteria and their strong cell walls.

Prokaryotes, the bacteria, are the simplest organisms. Prokaryotic cells are small, consisting of cytoplasm surrounded by a plasma membrane and encased within a rigid cell wall, with no distinct interior compartments (figure below). A prokaryotic cell is like a oneroom cabin in which eating, sleeping,
and watching TV all occur in the same room. Bacteria are very important in
the economy of living organisms. They harvest light in photosynthesis, break
down dead organisms and recycle their components, cause disease, and are involved
in many important industrial processes.

Structure of a bacterial cell. Generalized cell organization of a bacterium. Some bacteria have hairlike growths on the outside of the cell called pili.

Strong Cell Walls
Most bacteria are encased by a strong cell wall composed of peptidoglycan, which consists of a carbohydrate matrix (polymers of sugars) that is cross-linked by short polypeptide units. No eukaryotes possess cell walls with this type of chemical composition. With a few exceptions
like TB and leprosy-causing bacteria, all bacteria may beclassified into two types based on differences in their cell walls detected by the Gram staining procedure. The name refers to the Danish microbiologist Hans Christian Gram, who developed the procedure to detect the presence of certain disease-causing bacteria. Gram-positive bacteria have a thick, single-layered cell wall that retains a violet dye from the Gram stain procedure, causing the stained cells to appear purple under a microscope. More complex cell walls have evolved in other groups of bacteria.In them, the wall is multilayered and does not retain the purple dye after Gram staining; such bacteria exhibit the background red dye and are characterized as gramnegative.


The susceptibility of bacteria to antibiotics often depends on the structure of their cell walls. Penicillin and vancomycin, for example, interfere with the ability of bacteria to cross-link the peptide units that hold the carbohydrate chains of the wall together. Like removing all the nails from a wooden house, this destroys the integrity of the matrix, which can no longer prevent water from rushing in,swelling the cell to bursting.Cell walls protect the cell, maintain its shape, and prevent excessive uptake of water. Plants, fungi, and most protists also have cell walls of a different chemical structure, which we will discuss in later chapters.

Long chains of sugars called polysaccharides cover the cell walls of many bacteria. They enable a bacterium to adhere to teeth, skin, food—practically any surface that will support their growth. Many disease-causing bacteria secrete a jellylike protective capsule of polysaccharide around the cell.

Science and religion can coexist!

Just when you thought science and religion can’t coexist, a new worldwide study comes assuring that not all scientists are atheists.


Are all scientists atheists? Do they believe religion and science can co-exist? These questions and others were addressed in the first worldwide survey of how scientists view religion, released by researchers at Rice University.No one today can deny that there is a popular ‘warfare’ framing between science and religion, said principal investigator Elaine Howard Ecklund, adding that this is a war of words fueled by scientists, religious people and those in between.The study’s results challenge longstanding assumptions about the science-faith interface. While it is commonly assumed that most scientists are atheists, the global perspective resulting from the study shows that this is simply not the case.


Ecklund noted that more than half of scientists in India, Italy, Taiwan and Turkey self-identify as religious and it’s striking that approximately twice as many ‘convinced atheists’ exist in the general population of Hong Kong, for example, (55 percent) compared with the scientific community in this region (26 percent).
The researchers did find that scientists are generally less religious than a given general population. However, there were exceptions to this: 39 percent of scientists in Hong Kong identify as religious compared with 20 percent of the general population of Hong Kong, and 54 percent of scientists in Taiwan identify as religious compared with 44 percent of the general population of Taiwan. Ecklund noted that such patterns challenge longstanding assumptions about the irreligious character of scientists around the world.
Ecklund said that the study has many important implications that can be applied to the university’s hiring processes, how classrooms and labs are structured and general public policy.

“Science is a global endeavor,” Ecklund said. “And as long as science is global, then we need to recognize that the borders between science and religion are more permeable than most people think.”

New tool to track embryo's brain development in 3D

Researchers, including one of Indian-origin, have developed a new open-source software that can help track the embryonic development and movement of neuronal cells in 3D throughout the body of the worm.

The tool could help better understand brain development in humans, researchers said.

Although scientists have identified a number of important proteins that determine how neurons navigate during brain formation, it is largely unknown how all of these proteins interact in a living organism.  

Researchers chose Caenorhabditis elegans (C elegans), because it has only 302 neurons, 222 of which form while the worm is still an embryo.

While some of these neurons go to the worm nerve ring (brain) they also spread along the ventral nerve cord, which is broadly analogous to the spinal cord in humans. 

"We don't yet understand neurodevelopment even in the context of the humble worm, but we're using it as a simple model of how these factors work together to drive the development of the worm brain and neuronal structure," said Hari Shroff, head of the research team at the US National Institute of Biomedical Imaging and Bioengineering (NIBIB).

"We're hoping that by doing so, some of the lessons will translate all the way up to humans," said Shroff.

The team at NIBIB, in collaboration with Daniel Colon-Ramos at Yale University and Zhirong Bao at Memorial Sloan-Kettering Institute in US, developed new microscopes that improved the speed and resolution, allowing them to record the embryogenesis of these worms without damaging them through too much light exposure while still getting the resolution needed to clearly see individual cells. 

The second problem was that during development the worm begins to "twitch", moving around inside the egg. The folding and twisting makes it hard to track cells and parse out movement, the researchers said.

Finally, it can be challenging to determine where a neuron is in 3D space while looking at a two-dimensional image - especially of a worm that is folded up.

Researchers made several cells in the embryo glow with fluorescent proteins to act as markers. 

When a microscopic image of these cells is fed into the programme, the computer identifies each cell and uses the information to create a model of the worm, which it then computationally "untwists" to generate a straightened image.

The programme also enables a user to check the accuracy of the computer model and edit it if any mistakes are discovered.

"In addition, users can also mark cells or structures within the worm embryo they want the programme to track, allowing the users to follow the position of a cell as it moves and grows in the developing embryo," Ryan Christensen, a postdoctoral fellow at NIBIB, who led the project.

"This feature could help scientists understand how certain cells develop into neurons, as opposed to other types of cells, and what factors influence the development of the brain and neuronal structure," said Christensen.

The research was published in the journal eLife.    

10 percent people suffer from food-borne diseases: WHO

One out of every 10 people worldwide suffer from food-borne diseases annually, and children and the poor suffer the most, the findings of a World Health Organisation task force show."The groups most adversely affected by the foodborne diseases are children and people in low-income regions of the world," said task force leader Arie Havelaar from the University of Florida.    The announcement, made on Wednesday, comes after more than eight years of research.

"Of those who lost years to ill-health, disability or early death, 40 percent were children under five years old, even though they constitute only nine percent of the world population. Foodborne illnesses affect people on the African continent the most, followed by sub-regions of Southeast Asia and the eastern Mediterranean.    The World Health Organisation (WHO) created the Foodborne Disease Burden Epidemiology Reference Group in 2007 to study global variation in the impact of foodborne disease.       After considering the known disease-causing agents that can be transmitted by food, the group identified 31 hazards as the most necessary to include.

The group found that these 31 foodborne hazards caused 600 million foodborne illnesses and 420,000 deaths in 2010.

Results from the study indicate that up to 33 million healthy life years are lost each year due to foodborne diseases each year -- a number on par with the "big three" infectious diseases -- HIV/AIDS, malaria and tuberculosis -- and air pollution.

Diarrheal disease agents were the most frequent causes of foodborne illness - particularly norovirus and Campylobacter.

Non-typhoidal Salmonella enterica, also a diarrheal disease agent, is capable of causing blood poisoning in people with weakened immune systems and was a major cause of death among the pathogens chosen for the study.

Other major pathogens causing foodborne disease deaths included Salmonella Typhi, a subspecies of Salmonella enterica and Taenia solium, a tapeworm that comes from pork products; and the hepatitis A virus.

The findings were presented in a WHO technical report.         

Google launches new Cardboard Camera app to create 3D VR images

Google has released a new app for the Cardboard. The app called Cardboard Camera lets you create 360 degrees panoramic photos in virtual reality. Android users can download the app via Google Play Store

To take a panoramic photo using cardboard, the user has to move 360 degree in a circle. It will also record audio and the images when seen using the Cardboard will appear to be 3D. This means when you place the smartphone inside a Cardboard and view to view VR images, they will appear 3D.
Google says VR photos are three-dimensional panoramas that come with slightly different views for each eye. Near things look near and far things look far, and one can look around to explore the image in all directions.
“With Cardboard Camera, anyone can create their own VR experience. So revisit the mountaintop that took hours to hike, or the zoo where you saw (and heard) the monkeys, or your birthday party with the cake out and candles still lit. Capture the moments that matter to you and relive them anytime, from anywhere,” Google further explains in a blogpost

In September, there were reports about Microsoft also working on a Google Cardboard-rival called VR Kit. Microsoft Hololens has definitely earned some praise in the market and it is possible that the company is using the cardboard kit as a means to lower the barrier and encourage VR developer interest.
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BIODIVERSITY OF INDIA & THE CONVENTION ON BIOLOGICAL DIVERSITY (CBD)

Biodiversity is the variety of living organisms on the earth. It includes diversity within species or between species and of eco-systems. The earth’s biological resources are vital to humanity’s economic and social development. Globally, so far 1.75 million species have been identifi ed against the estimates ranging from 3 to 100 million. There is growing recognition that biodiversity is a global asset of tremendous values to present
and future generations. At the same time, the threat to species and ecosystems has never been as great as it is today, as a result of which species extinction caused by human activities continues at an alarming rate. This calls for global and national actions towards conservation of biodiversity.

India: A Treasure of Biodiversity
India is known for its rich heritage of biodiversity. In biological diversity parlance,India is one of the 17 mega-diverse countries in the world. With only 2.4% of theworld’s area, India accounts for 7-8% of the world’s recorded plant (about 45,000, of which approximately 15,000 are of known medicinal value) and animal species (about 91,000). India’s ten biogeographic zones possess an exemplary diversity of ecological
habitats like alpine forests, grasslands, wetlands, coastal and marine ecosystems, and desert ecosystems. India has four out of thirty four global biodiversity hotspots, which is an indicator of high degree of endemism (of species) in India. About 5,150 plant species and 1,837 animal species are endemic to India. India’s biodiversity includes wild relatives of agricultural crops and domesticated animals. India has 16 major types and 251 subtypes of forests. The large mosaic of distinct agro-ecosystems has contributed to
diverse cropping pattern and systems across the country.

Conservation of India’s Biodiversity:
A Progressive Framework Environment protection is enshrined in the Constitution of India [Article 48A and Article 51A (g)]. Wide-ranging policies,programmes and projects are in place, which directly or indirectly
serve to protect, conserve and sustainably use the country’s biological resources. These include the Forest (Conservation)Act, Wildlife (Protection) Act, Biological Diversity Act, National Green Tribunal Act, National Biodiversity Action Plan, National Forest Policy, National Wildlife Action Plan, National Forestry
Action Programme, National Environment Policy and National Action Plan on Climate Change.

India is committed to conservation of biodiversity. This is not only because of India’s international obligations as a signatory to the Convention on Biological Diversity, but because India believes that protecting our biodiversity is a critical national priority as it is linked to local livelihoods of millions of people
in the country. Sustainable use of our biodiversity, therefore,has both ecological and economic value. It is with this objective that India has enacted Biological Diversity Act, 2002 and set up a National Biodiversity Authority (NBA) in 2003 with an explicit mandate of promoting conservation of biological resources and associated knowledge as well as facilitating access
to them in a sustainable manner.

Fauna of India India  has some of the world's most biodiverse regions. The political boundaries of India encompass a wide range of ecozones—desert, high mountains, highlands, tropical and temperate forests, swamplands, plains, grasslands, areas surrounding rivers, as well as island archipelago. It hosts 3 biodiversity hotspots: the Western Ghats, the Himalayas and the Indo-Burma region. These hotspots have numerous endemic species.
India, for the most part, lies within the Indomalaya ecozone, with the upper reaches of the Himalayas forming part of the Palearctic ecozone; the contours of 2000 to 2500m are considered to be the altitudinal boundary between the Indo-Malayan and Palearctic zones. India displays significant biodiversity. One of eighteen megadiverse countries, it is home to 7.6% of all mammalian, 12.6% of all avian, 6.2% of all reptilian, 4.4% of all amphibian, 11.7% of all fish, and 6.0% of all flowering plant species.
The region is also heavily influenced by summer monsoons that cause major seasonal changes in vegetation and habitat. India forms a large part of the Indomalayan biogeographical zone and many of the floral and faunal forms show Malayan affinities with only a few taxa being unique to the Indian region. The unique forms includes the snake family Uropeltidae found only in the Western Ghats and Sri Lanka. Fossil taxa from the Cretaceous show links to the Seychelles and Madagascar chain of islands.The Cretaceous fauna include reptiles, amphibians and fishes and an extant species demonstrating this phylogeographical link is the purple frog. The separation of India and Madagascar is traditionally estimated to have taken place about 88 million years ago. However, there are suggestions that the links to Madagascar and Africa were present even at the time when the Indian subcontinent met Eurasia. India has been suggested as a ship for the movement of several African taxa into Asia. These taxa include five frog families (including the Myobatrachidae), three caecilian families, a lacertid lizard and freshwater snails of the family Potamiopsidae. A fossil tooth of what is believed to be of from a lemur-like primate from the Bugti Hills of central Pakistan however has led to suggestions that the lemurs may have originated in Asia. These fossils are however from the Oligocene (30 million years ago) and have led to controversy. Lemur fossils from India in the past led to theories of a lost continent called Lemuria. This theory however was dismissed when continental drift and plate tectonics became well established.

India is home to several well-known large mammals, including the Asian elephant, Bengal tiger, Asiatic lion, leopard and Indian rhinoceros. Some of these animals are engrained in culture, often being associated with deities. These large mammals are important for wildlife tourism in India, and several national parks and wildlife sanctuaries cater to these needs. The popularity of these charismatic animals have helped greatly in conservation efforts in India. The tiger has been particularly important, and Project Tiger, started in 1972, was a major effort to conserve the tiger and its habitats. Project Elephant, though less known, started in 1992 and works for elephant protection. Most of India's rhinos today survive in the Kaziranga National Park. Some other well-known large Indian mammals are: ungulates such as the water buffalo, nilgai, gaur and several species of deer and antelope. Some members of the dog family such as the Indian wolf, Bengal fox, golden jackal and the dhole or wild dogs are also widely distributed. It is also home to the striped hyaena. Many smaller animals such as macaques, langurs and mongoose species are especially well known due to their ability to live close to or inside urban areas.

Biodiversity hotspots

The Western Ghats

The Western Ghats are a chain of hills that run along the western edge of peninsular India. Their proximity to the ocean and through orographic effect, they receive high rainfall. These regions have moist deciduous forest and rain forest. The region shows high species diversity as well as high levels of endemism. Nearly 77% of the amphibians and 62% of the reptile species found here are found nowhere else. The region shows biogeographical affinities to the Malayan region, and the Satpura hypothesis proposed by Sunder Lal Hora suggests that the hill chains of Central India may have once formed a connection with the forests of northeastern India and into the Indo-Malayan region. Hora used torrent stream fishes to support the theory, but it was also suggested to hold for birds. Later studies have suggested that Hora's original model species were a demonstration of convergent evolution rather than speciation by isolation.
More recent phylogeographic studies have attempted to study the problem using molecular approaches.There are also differences in taxa which are dependent on time of divergence and geological history. Along with Sri Lanka this region also shows some fauna similarities with the Madagascan region especially in the reptiles and amphibians. Examples include the Sinophis snakes, the purple frog and Sri Lankan lizard genus Nessia which appears similar to the Madagascan genus Acontias. Numerous floral links to the Madagascan region also exist. An alternate hypothesis that these taxa may have originally evolved out-of-India has also been suggested.

Rhinoceros unicornis, Kaziranga