Losing weight too a gender biased affair.

fatty

In general it has been observed that women , as compared to men, find it to difficult to loose weight. Well, thats because of ‘her’ differently wired brain system, as suggested by a new study conducted by the scientists at the University of Aberdeen, UK. For more details check out here.

http://www.hindustantimes.com/health-and-fitness/it-s-not-you-it-s-your-gender-why-losing-weight-is-tough-for-women/story-NHdd7ljBjw0NOa0FWHSHAM.html

The future antibiotics: Enzybiotics

enzy
source: http://www.microbiologysociety.org

Overuse and abuse of antibiotics are largely responsible for the increasing prevalence of  multi-drug resistant bacteria. Hence, the reseachers have come up with new class of antibiotics-enzybiotics, with novel mechanism of action against drug-resistant pathogens.

The global health is gripped with numerous challenges. On one side it is facing the dire consequences of the climate change while on the other side it is dreaded with plentiful of epidemics and pandemics. One such most faced challenge is increasing number of bacterial infections that have become resistant to antibiotic regimen, as a result, superbugs like MRSA and NDM-1 have dramatically escalated statistics dreading the public safety. Thus, there is an urgent need to find an alternative way to address the problem in an efficient course of action.

Enzybiotics is a hybrid of enzyme and antibiotic. These are bacterial cell wall degrading enzymes having antibacterial and/or antifungal activity, thus, proving to be a potential subsitute over conventional antibiotics. The term was first coined in 2001 by Nelson et al. They consist of lytic enzymes of class peptidoglycan hydrolases like lysins, bacteriocins, autolysins and lysozymes. The significant characertics of enzybiotics are:

  • Their novel approach for antibacterial action.
  • Their ability to kill antibiotic-resistant bacteria, and
  • Their low probability of developing bacterial resistance.

Mode of Action

Enzybiotics majorly belong to the class peptidoglycan hydrolases. When these enzymes are added exogenously to Gram positive bacteria they cause rapid disintegration of the cell wall as there is no outer membrane present to hinder their action. But, in Gram negative bacteria outer membrane obtructs their way to to the cell wall ,thus, limiting their activity. Enzybiotics have narrow host range, therefore, they selectively target their pathogenic hosts without affecting the surrounding microflora.

Major classes of Enzybiotics

  1. Bacteriocins: Bacteriocins are proteinaceous extracellular substanaces that are produced by both Gram positive and Gram negative species. They are either produced spontaneously or induced by certain chemicals such as mitomycin C. They inhibit the growth of similar or closely related bacterial strains. These are narrow spectrum class of antibiotics. Their lethal activity involves adsorption to the specific receptors on the exterior of specific bacteria, followed by metabolic, biological and morphological changes resulting in the killing of bacteria. Bacteriocins are produced by non-pathogenic bacteria that normally resides in human body. Antibiotic use results in the loss of these harmless and useful bacteria, paving way for the opportunistic pathogens to invade the human body.
  2. Lysins: Lysins, also known as endolysins or murein hydrolases are peptidoglycan degrading enzymes released by bacteriophages that help in lysis of bacterial cell wall at the end of lytic cycle to release the progeny phage particles.They are incresingly being used as antibacterial agent owning to their high efficacy and specificity. They have characterstic lysis or cell-wall binding domain and degrade peptidoglycan with glycosidase, amidase, endopeptidase, or lytic tansglycosylase activities. They are species specific but some broad spectrum lysins have also been reported. They are highly effective against Gram positive bacteria as the outer memebrane is absent as against Gram negative where outer membrane is present.
  3. Lysozymes: Also known as muramidase or N-acetylmuramide glycanhydrolase, globular protein of 129 amino acid residues.They belong to the class glycoside hydrolase that catalyse the hydrolysis of 1,4-β-linkages. They cleave the 1,4-β-linkages between N-acetyl muramic acid and N-acetyl-D-glucosamine in peptidoglycan structure. Lysozymes have been found in secretion like tears, mucus, saliva and human milk. Egg white (albumin) is an abundant source of lysozyme. It significantly contributes to innate immunity of humans . Lysozymes are most powerful natural antibacterial and antiviral subtance. It also exhibits anti-inflammatory, anti-cancer and immunomodulatory activities.
  4. Autolysins: This enzyme hydrolysis the biological component or tissue in which it is produced. These are found in all peptidoglycan containing bacteria. The enzyme functions similar to lysozyme. It cleaves the 1,4-β-linkage between N-acetyl glucosamine and N-acetyl muramic acid. They break down the peptidoglycan matrix and assist the bacterial cell in growth and cell division. They present a promising target for the development of new type of antibiotics.
  5. Defensins and cathelicidins: These are antimicrobial peptides found in the lysosomes of macrophages and polymorphonuclear leukocytes and keratinocytes. They are a part of mammalian innate immunity system that help fight bacterial infections. Cathelicidins obliterate the lipoprotein membranes of microbes enveloped in phagosomes after fusion with lysosomes in macrophages.
  6. Virion-associated peptidoglycan hydrolases (VAPGH): These are phage encoded lytic enzymes that disintegrate the peptidoglycan of the bacterial cell wall during infection. Their mode of action involves the generation of small hole through which the phage tail enters, crosses the cell envelop and releases the phage genetic material at the onset of the infection cycle. VAPGHs are highly specific, thermostable and have high modular organisation. They serve as a potential candidates for the use as enzybiotics.

Examples

Various enzybiotics with their host range, source and types are summerised below.

Enzybiotic name Enzybiotic class Source Enzymatic specificity Antibacterial range
           Ply C         Lysin Phage C1     Amidase S. pyrogens group C and E
           P al         Lysin Phage DP     Amidase S. pneumonia
Lambda SA 2-E      Endolysin Staphylococcal phage   Endopeptidase S.aureus
           P ly G         Lysin  Phage Gamma    Amidase B.anthracis
           Lyt A     Autolysin S. pneumoniae    Amidase S.pneumoniae
            Lysostaphin    Bacteriocin S. simulans Endopeptidase S.aureus, Staphylococci
Hen egg white lysozyme    Lysozyme Hen’s egg white Muraminase Gram positive bacteria

Some Potential Applications of Enzybiotics

  1. In Food industry: Enzybiotics have been widely used in food industry as food additives and preservatives like in the production of cheese and wine. The Food and Drug Administration (FDA) has given a nod to the use of enzybiotics to control Listeria monocytogenes in cheese, classifying them as GRAS (generally recognised as safe) in the year 2006 which was later extended to enzybiotic use on all food products in 2007.
  2. In Medical industry: Their novel approach for antibacterial action, ability to kill antibiotic-resistant bacteria and very low possibility to develop bacterial resistance make them potent antibacterial and antifungal agents. They are used in eye drops, toothpastes etc. Their other uses are well documented above.
  3. In Farm industry: In the recent years the misuse and overuse of antibiotics in  food producing livestock have raised a serious alarm on increasing number of antibiotic resistant bacteria, thus, escalating the risk of antibiotic resistant infections in humans. Enzybiotics present a novel way to combat the problem. They have been successfully used in treating septicaemia and meningitis in chikens and calves and also used as biocontrol agenets to control the number of Salmonellla in poultry products.

Enzybiotics present a redoubtable cover over antibiotics. Their objectionable side effects have been rarely reported. Therefore, they are very effective to be used as antibacterial and antifungal agents. Researches are being carried out on further potentials of enzybiotics and it is hoped that they present a  promosing future to medical community by help combating the antibiotic resistant strains of pathogens.

References:

  1. Ruchi Tiwari, Kuldeep Dhama,Sandip Chakraborty, Sanjay Kapoor. Enzybiotics: New weapon in the army of antimicrobials: A review. Department of Veterinary Microbiology, College of Veterinary Sciences, Uttar Pradesh. Asian Journal of Animal and Veterinary Advances 9(3): 144-163, 2014.
  2. G K Sudhakar, venkatesh Kamath B and Aravind Pai. Enzybiotics: A review. Department of Pharmaceutical Chemistry, Manipal College of Pharmaceutical Sciences, Manipal University, Manipal. International Journal of Pharmacological Research. DOI: 10.7439/ijpr.
  3. M A Daw, F R Falkiner. Bacteriocins: Nature, function and structure. Faculty of Medicine, Alfateh University of Medical Sciences, Tripoli, Libya. Micron December 27(6): 467-479.
  4.  Enzybiotics and Phages:Safe alternatives to antibiotics in the control of food safety. http://www.microbiologysociety.org

We are the SUPERORGANISMS!Part 3: The Oral Microbiome

oral microbeThe oral cavity or mouth is the major portal into the human body. The food is taken up by the mouth, masticated and mixed with saliva, making its way to the oesophagus and intestinal tract for the process called digestion. The oral cavity or the buccal cavity habours a number of bacterial species. It includes several distinct microbial habitats like teeth, gingival sulcus, tongue, cheeks, lips, hard palate, soft palate, tongue and saliva. The oral microbiome include microorganisms found within the oral cavity to the distal end of the oesophagus. But most of the studies have been obtained from within the oral cavity.

It has been estimated that around 600-700 microbial species inhabit the oral cavity. The oral microbiome majorily includes Streptococci, Neisseria, Veillonella, Actinomyces and other obligate anerobes.These species ehibit mutalistic relationship with their host, preventing other pathogens from adhering to the oral mucosa. The gingival sulcus has the highest concentration of the anerobic species, mainly Spirochaete, Vibrio and S. melaninogenicus. 

Both Gram-negative and Gram-positive bacteria colonise the buccal cavity. Some the common species found are briefed below:

Gram-positive Bacteria

  1. ActinomycesThese are facultative anaerobes that normally inhabit the mouth. They are found in the gum region. In oral cavity they are opportunistic pathogens. Their number increases in gingivitis and are found to be associated with root caries. A. israelli , an opportunistic pathogen, causes Actinomycosis which is marked by the oral abscess and leads to a condition commonly referred to as ‘lumpy jaw’. The infection can also end up in locked jaw, where mouth does not open normally. Antibiotics like  Penicillin, Tetracyclins, Erythromycins are supplemented to curb the infectious state. The best precaution to be taken is a proper oral care and practise good oral hygiene.
  2. Lactobacillus: Lactobacilli species are found in the oral cavity in the early years of a child’s life. In adults they are found in the root caries. They are highly concentrated in the saliva, on the dorsum of the tongue, in the mucuous membrane, in dental plaque and in lesser number on the tooth surface. In general, they are known to have symbiotic relationship with their host and help in preventing the adherence of other pathogenic strains in the buccal cavity. But some strains like L.acidophillus and L.paracasei are known to possess carcinogenic properties.
  3. Streptococci: These are facultative anaerobes that are the majoroty colonizers of the oral cavity. About 25 species have been known to inhabit the mouth. In general they share a commensal relationship with their host but under special circumstances they become pathogenic.  S. mutans and S. sanguinis colonise the dental surface and gingivia. Other species include S.salivarius, S. mitis, S.angiosus.  The species are associated with dental plaques and toothe decay owning to their ability to form biofilms.

Gram-Negative Bacteria

  1. Porphyromonas: P. gingivilis is an anaerobic oral microbe. It is periodontopathic pathogen that is responsible for the inflammatory response and a condition called periodontitis. It is accumulated in and around gingival crevice.The bacterium along with Trepanoma denticola and Tenerella forsythia forms the so called “red complex” , which is strongly associated periodontal destruction. Another species P.endodontalis , anaerobe , also causes peridontitis, endodontic infections , gingivitis and tooth pulp necrosis. It colonises majorly in gingival epithelial cells.
  2. Veillonella: V.parvula  is a strict anaerobe that is normally found in buccal cavity. In general, it is non-pathogenic but have been associated to cause periodontitis.Together with S.mutans it forms biofilms that are known to cause dental plaques. It is susceptible to the antibiotic penicillin.
  3. Actinobacillus actinomycetemcomitans: It is facultative anaerobe and are found in periodontal pocket of the oral cavity. It is most completely studied periodontal bacteria. It is the major cause of periodontitis, bacterial infection of the teeth that ultimately results in tooth loss. It is associates with other oral bacteria to form biofilms.
  4. Trepenoma denticola: It is a motile anaerobic bacteria found in oral cavity, concentrated in subgingival dental plaque. It is associated periodontal disease and gum inflammation. It also interacts with other oral microflora to form biofilms.

These are some of the studied bacterial populatioin found in the oral cavity and the diseases associated with them. The most given advice by the dentists to keep away the pathogenic strains is to maintain a good and healthy oral hygiene and avoiding high sugar content food supplements.

Contagious Cancers!

contagious cancerIn general, Cancer is not contagious. But there are certain types of cancers discovered in animals that can be transmitted from animal to animal. Transmissible cancers are rare in humans. Devil Facial tumour disease (Tasmanian devil), Canine Transmissible venereal tumour (dogs), Contagious Reticulum Cell Sarcoma (Syrian hamster) and Soft Shell Clams (Mya arenaria) are contagious cancers discovered so far. Recently, reserachers have found another type of contagious cancer in Tasmanian devil. For more information check:

http://timesofindia.indiatimes.com/life-style/health-fitness/health-news/Another-contagious-cancer-type-found-in-Tasmanian-devils/articleshow/50377864.cms

We are the SUPERORGANISMS! Part 2: Skin Microbiota

skin microfloraSkin is the outermost covering of the human body. It is the largest organ with an estimated area of 20 square feet. It forms the first line of defense, protecting the body against pathogens, regulates the body temperature and enables the sensation of heat, touch and cold. It is divided into three layers: epidermis– upermost waterproof protective layer, followed by dermis-consists of connective tissues, hair follicles and sweat glands, followed by subcutaneous layer– lowermost layer composed of connective tissues. The pH and temperature of the skin depends on the area of the body it covers. In general, the pH ranges from 5.6 to 6.4 and temperature from 25 to 35 degree Celsius.

The microbes residing on the skin constitute the skin microbiota. In general, the microbes are found all over the body but dermatologists have classified the three anatomical sites on the skin for their microbiological differences.These regions are distinguised based on the pH, temperature , moisture and concentration of skin lipids. The regions are:

  1. The Dry site: Includes forearm, legs, hands and feet.Since the area is exposed to the outer environment, it has most diverse microbial population.
  2. The Moist site: Includes axilla, toe webs, groins and  beneath the breast areas.
  3. The Oily site: Includes head, neck and face. This area has sebaceous glands that secret an oily susbstance called sebum.

The oily site is more species rich than the dry and moist sites.The microflora inhabiting the skin include both bacteria and fungi e.g.Staphylococcus, Proprionibacteria, Cornybacterium, Malasezzia, Dermabacter and Micrococcus.

The Bacterial Inhabitants

According to a research the human skin is a home to 113 phylotypes that belong to six bacterial divisions. Some of the common species found are described below.

  1. Staphylococcus epidermidis : It is a Gram-positive bacterium, non-motile and facultative anaerobe found around sebaceous glands and moist areas. In general , it is not pathogenic but in immunosuppresed individuals it causes infections. The infections acquired are mostly nosocomial. It forms biofilms on catheters and other surgical implants implanted within the body. The biofilms formed are resistant to antibiotic treatments, therefore, taking the infection to an advanced level. Vancomycin have been , so far, the prefeered antibiotic that effectively helps fighting the infection.
  2. Staphylococcus aureus:  It is Gram-positive, immobile and facultative anerobe found around sebaceous glands and moist areas. It is pathogenic in nature and is the most common cause of staph infections. It is also the causative agent of mild skin infections, invasive diseases like bacteremia, wound infection, etc. and toxin-mediated diseases like food poisioning, scaled skin syndrome, etc. It also forms biofilms and is resistant to antibiotics. The emergence of its antibiotic resistant strain Methicillin resistant Staphylococcus aurues has now come in the hit-list for the researcher s and doctors as it is increasly victimising  the people.
  3. Propionibacteria: It is a Gram positive bacteria. They share a commensal relationship with humans and inhabit on the skin, majorily concentrated around sebaceous glands. In general they are non-pathogenic but often cause infections when come in contact with blood or any other body fluid. P. acnes is reponsible for acne vulgaris and is also associated with anaerobic arthritis and in some cases with osteomylitis and endocarditis.Antibiotics such as penicillin, carbapenems and clindamycin are generally used for the treatment.
  4. Cornybacteria: It is Gram-positive aerobic bacteria found in moist area of the human skin.Generally, they are non-pathogenic but some species are known to be infective. C.diptheriae is the causative agent of dipetheria, a respiratory disease mainly affecting the children.Its other pathogenic species in humans are C.amicolatum, C.striatum, C.xerosis  that mostly affect the immunosuppressed patients. The bacteria is also responsible for skin infections and endocarditis. C.striatum causes axillary odor while C.minutissimum  cause erythrasma.
  5. Proteobacteria:  It is a Gram-negative , facultative or  obligatory anaerobic. They are concentrated in the dry areas of the skin. They are mostly pathogenic and includes species like  Escheresia, Salmonella, Vibrio, Helicobacter and Yersenia. 

The Fungal Inhabitants

According to a study around 14 genera of fungi have been found to colonise human skin. Majority of the species are concentrated around heels, toenails and beween the toes. Other areas include palm, forearm and elbows. Some of the common species are Candida albicans, Torulopsis, Trichopytom rubrum, Alternaria alternata, Fusarium, Rhizopus stolonifer, Penicillum etc. Some of the common fungal infections are:

  1. Athelete’s Foot: It is caused by a microscopic fungi Trichopytom rubrum that lives on dead skin, hair , toenails and outer skin layers. The disease may be interdigital, mocassin (entire sole of the foot and may extend to the sides of foot) and Vesicular (between toes, on the heel and top of the foot). It is treated with antifungal medication.
  2. Jock Itch: It is a skin infection caused by a fungus Tinea. Since the fungus resides in warm moist area, therefore, the infection majorily occurs in genital area, inner thigh regions and buttocks. It is treated with antifungal sprays and creams.
  3. Ringworm:  It is a skin inection caused by fungus  Tinea. It can occur anywhere on the body and is contagious. Treatment generally includes antifungal creams like Lmicil, Mycelex, etc.
  4. Yeast Infections: It is caused by yeast Candida albicans.  Yeast infections are not contagious. They mostly occur in warm, moist, oily area, like armpits and groin.It is alo responsible for diaper rashes in infants and vaginal yeast infections. They are treated with anti-yeast medications.

As described above the skin is inhabited by both bacterial and fungal species, of which some are pathogenic. In defensive mode, the skin protects itself by secreting some antimicrobial peptides like cathelicidins that keep a check on the proliferation of skin microbes. These peptides reduce the microbes and also help release cytokines which induces inflammation, angiogenesis and reepitheliazation. The acidic pH of the skin due to lactic acid found in the sweat also helps to control on the microbe number.

The Band-Aid of the Future!

band aids

Image source: MIT gallery

The Twenty First century has witnessed the so-called ‘Technology Revolution’ and that too at an enormous scale. The revolution still continues. From smart phones to smart computers to smart television sets we have now the Smart Band-Aid. The stretchy hydrogel band aid designed by the MIT engineers are the band-aids of the future.These tiny stretch can incorporate temperature sensors, LED lights, other electronics along with drug delivery channels. For more details click below.

http://www.sciencedaily.com/releases/2015/12/151207113854.htm