Lactobacillus Casei
Relevant issue/subject identified and appropriately introduced
In the backdrop of high cases of civilization diseases, industry and science in general direct their effort toward food products. In particular, interest is directed toward research beyond the regular nutritional function to deliver additional health benefits. In essence, science is trying to minimize risk of diseases. This has led to the emergence of what is commonly referred to as functional foods. The term encompasses a broad range of products and relates to foods that possess a potentially positive impact on health past basic nutrition. Probiotics or bifidobacteria are an example. The consumption of lyophilized or living cultures of bifidobacteriais known to have several benefits including enhancing the immune system action and prevent coronary diseases as well as cancer. The beneficial consequences of bifidobacteria on gastroeneteretis, bowel syndrome, hyperlipidemia, inflammatory bowel disease, diarrhea and hepatic disease are well known. Nevertheless, the most frequently used probiotic products include bio-yoghurts retailed by wholesalers and others. Worth noting is that besides the archetypal yoghurt strains including Streptococcus thermophilus and lactobacillus delbrueckii ssp bulgaricus, bio-yoghurts contain cultures of live bifidobacteria such as lactobacillus casei and others. This indicates a rising consumer interest in such products in addition to commercial competition that has meant that producers are competing in diversifying range of goods/products. In most cases, the assortment takes the form of new and exciting flavor achieved through adding rare fruit. Without a doubt, such actions are taken to ensure competiveness in the complex market of today’s world. However, while research on probiotics has increased over the last decades, few works exist describing the manner in which they function leading to the desired health benefits. In essence, majority of researchers are yet to establish the manner in which such probiotics as lactobacillus casei function thus affecting human health. Rather, available scientific studies on probiotics focuses on the products containing them including yoghurts. This has meant that the effects lactobacillus and others on human system has been given a peripheral role in the studies. It follows that while consumers are aware of some of the benefits derived from consuming related products, many do not know the best products to choose from the saturated market. In sum, studies are yet to provide concrete evidence on the manner in which lactobacillus casei and others function thus enhancing the human system in one way or the other.
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Concise and clear discussion of the current status of knowledge in the chosen subject area.
Lactobacillus casei strains represent gram-positive, facultative anaerobic, industrially significant LAB (lactic acid bacteria) that has been principally used as fibidobacterias and specialty cultures for various products development. In fact, it has been suggested that their wide commercial applications may be a reflection of their extraordinary ecological adaptability to different habitats. Nevertheless, Lactobacillus casei may be isolated out of raw as well as fermented dairy products (including yoghurts) and animal products. Despite all these findings, many dimensions or subjects involving the topic of Lactobacillus casei are at infancy or unknown altogether. As mentioned above, few works exist describing the manner in which probiotics function leading to the desired health benefits. In most cases, such a situation results from the failure to understand the genetic basis regarding the ecological flexibility in lactobacillus casei and others. Currently, the field of probiotics is filled with comparative genomic studies suggesting extensive gene loss as well as gene acquisitions throughout evolution of lactobacilli –presumably through bacteriophage or conjugation mediated hgts (horizontal gene transfers) that may have facilitated the adaptation to different ecological niches (Makarova 2006, p 15611-15616). For instance, milk as well as vegetable-associated sub-species of lactobacillus has been found to contain high level of genetic heterogeneity. As well, correlations have been demonstrated between specific gene acquisition or loss and the capacity of the species to inhabit specific habitats. Worth noting is that these are pure attempts to explain the manner in which probiotics including lactobacillus casei may affect human system (Makarova 2006, p 15611-15616). What is more, comparative genomic examination on lactobacillus strains of different sources show genomic regions with atypical base composition pinpointing evolutionarily recent acquisitions (Makarova 2006, p 15611-15616). In sum, it becomes evident that current knowledge does not add up and the manner in which lactobacillus casei and others affect human system is far from clear.
Worth noting is that molecular typing of Lactobacillus casei is vital to comprehending the evolutionary adaptation of the species to various ecological niches including the manner in which it helps our body system. What is more, definitive identification of Lactobacillus casei at the strain level is crucial for a range of industrial applications because it facilitates tracking of various strains with such industrially relevant characteristics as probiotic and antimicrobial elements. Currently, a number of molecular typing methods including randomly amplified polymorphic DNA, temporal temperature-gradient electrophoresis as well as pulsed-filed gel electrophoresis have been used in Lactobacillus casei (Farnworth 2008, p 49-54). The latter approach has been reported to show the highest discriminatory influence. Nevertheless, these the approaches have less effectiveness in describing underlying phylogenetic associations and thus making it difficult to establish how Lactobacillus casei and others work leading to health benefits. In essence, current approaches have proved to be of little use as far as the area of human health is concerned. In total, current knowledge in the area of probiotics is non-conclusive with regard to the manner in which it positively influences body system.
Evidence of wide range of reading
Most strains related to lactobacillus casei including shirota are rod-spaped and occur either singly or in pairs. In addition, they have been found to occur in short chains constituting 3 or 4 cells. Normally, lactobacillus casei strains are capable of growing at temperatures ranging from 27 through 43 degrees (Gaynor 2012, p 10). The strains can grow at low ph level of 3.5, but optimal ph is 6.5. Lactobacillus casei is a facultative homo-fermentative lactic acid bacteria, and produces 2 lactic acid molecules out of every glucose molecule – though it also generates small quantities of ethanol, acetate and diacetyl. Nevetheles, regarding the fermentative characteristic of lactobacillus casei strains, lactic acid is generated from adonitol, ribose, d-glucose, galactose, mannitol, D-mannose, salicin, turanose and sorbitol (Gaynor 2012, p 10). In addition, it is weakly generated from sucrose and inositol, but from inulin, glycerol, glycogen, starch and xylitol.
Lactobacillus casei relates to a harmless and non-pathogenic microorganism that is broadly recognized for its properties and attributes that have been shown to be beneficial to the human body. As a type of bacteria, lactobacillus casei helps to boost human body defense system through restricting the development of certain types of dangerous bacteria that lead to infection. This means that lactobacillus casei is beneficial and occurs naturally in human’s mouth as well as intestines. Essentially, the bacteria is known to produce amounts of lactic acid which is helpful in lowering the levels of ph in human’s digestive system thus impending the development of harmful bacteria. In addition, lactobacillus casei may be present if fermented dairy as well as fermented and fresh plant products. Such sources may include yoghurt and other food sources including fermented green olives. Different findings indicate that scientists have found the bacteria to have beneficial characteristics that improve human health. In particular, the bacteria is not only able to improve but also promote digestion. In addition, some strains associated with lactobacillus casei help manage diarrhea and others have an anti-inflammatory influence on the gut (Probiotic.org 2009, web). There are several other benefits linked to the bacteria as far as human health is concerned including alleviating constipation, lactose intolerance and general modulation of human immune system. In sum, lactobacillus casei is classified under friendly bacteria that are significant to proper functioning of the immune system, digestion and absorption of nutrients as well as protection against microorganisms that lead to disease. As such, ensuring that the body receives an appropriate level of lactobacillus casei is important. Nonetheless, probiotic strains including lactobacillus casei are selected to give beneficial impacts on the host as well as on the metabolism or composition of the intestinal microbiota without necessarily inflicting adverse transformations including production of toxins and epithelial cell invasion –effects that would imperil the nutritional or health status of the host. Resultantly, lactobacilli have been ingested on a daily basis since fermentation of milk was discovered. This includes the probiotic utilization of various lactobacillus species for decades, and possibly was ingested from the earliest history since they normally inhabit green plant material (Gaynor 2012, p 20). Research indicates that lactobacilli are ever-present because they are found in virtually all carbohydrate rich substances. Several authors also report that in healthy persons, lactobacilli are normal and found in the ileum, the oral cavity as well as the colon. In addition, they are dominant microorganism in human’s vagina. In sum, their close relation with human health is evident and their long application as probiotics without risk to humans has been noted. In fact, their significance is underlined by the fact that no pathogenic characteristic has been associated with them.
A discussion by Cabana et al (2006, p 407) observed that while probiotic’s optimal dose remains an area under investigation, there exists no reports of toxicity linked to exceeding a specific dose. This indicates that their pathogenic characteristic is quite low or non-existent altogether. On the other hand, Vandenplas et al (2007, p 46) noted that such probiotics as lactobacillus casei never colonize human’s grastro-intestinal tract because they become undetectable shortly after stopping the administration. The outcome is the absence of risks for long-term side effects. Bearnadeu et al (2008, p 157) noted that the risk –if any- of bacteremia from bifidobacteria and probiotic lactobacilli is 1 in a million. It can be concluded that the overall risk from lactobacillus and others presents a negligible imperil to consumers of such products as yoghurt. This also includes negligible risk to immune- compromised hosts. In addition, the bibliographical data has been shown to promote the hypothesis that the consumption of lactobacillus strains is not in any hazardous because lactobacillemia induced through food (including fermented dairy products) is extremely rare (Bearnadeu et al 2008, p 157).
According to Guerin-Danan et al (2000, 111-117 am jpdf), yoghurt is explained as a fermented milk obtained through specific fermentation of lactic acid –via the action of streptococcus thermophilus as well as lactobacillus bulgaricus. Ingestion of related products induces transformations in the equilibrium as well as metabolism of the microflora and may therefore a healthful effect on the host. Nevertheless, Guerin-Danan et al (2000, 111-117) notes that fermented milks including yoghurt have substantial health benefits and can be included in human’s diet from an early age. In fact, they act as good sources of vitamins and minerals and have small amounts of lipids. What is more, fermented milks including yoghurt help control the intake of dietary nitrogen elements in human body as well as supply many lactic acids. Nonetheless, the consumed lactic acid bacteria in some measure resist gastric acidity as well as bile salts. This means that it passes live via the gastrointestinal tract in which they may regulate the metabolism and balance of endogenous microflora. The regulation of such modifications is crucial to health because microflora (mouth and intestinal) can exert either advantageous or disadvantageous effects on the host. Guerin-Danan et al (2000, 111-117) also note that other lactic acid bacteria –particularly those related to lactobacillus – can be included in yoghurt to create fermented milks with definite desirable characteristics including new flavor. Additionally, various lactic acid bacteria are incorporated for the properties – signifying that probiotics can lead to benefits beyond basic nutrition.
According to Wu et al (2011, 1031-1039), lactobacillus casei strains have conventionally been recognized as probiotics. In addition, they have been frequently utilized as adjunct culture in fermented milks in which lactic acid stress is a commonly encountered environmental condition. Lactic acid bacteria relates to a heterogeneous group of bacteria that are applied to create fermented foods (including yoghurt), and are generally accepted as safe. In addition, lactic acid bacteria comprise a collection of microbes related via common metabolic functionality (i.e the creation of lactic acid as a major metabolic end product related to carbohydrate metabolism) and common physiological characteristics. These microbes are Gram positive, catalase-negative, non-spore forming as well as devoid of cytochromes all of which underline their potential in promoting health (Gaynor 2012, p 20). As well, they are preferential non-aerobes, but are acid- tolerant, aero tolerant and strictly fermetative. Even though they are not a closely efined group, lactic acid bacteria usually are considered to constitute a phylogenetically related general such as streptococcus and others. As a result of resemblance in its physiology, ecology and biochemistry, the genus (bifidobacterium) is frequently considered as a lactic acid bacteria – though it may be phylogenetically unrelated. With the exception of some species and strains including streptococcus and enterococcus, most lactic acid bacteria strains are deemed to have no pathogenic potential. Indeed, they are normally found in human’s oral cavity as well as digestive tract. In addition, the bacteria has conventionally known as a probiotic thus used in such commercial products as yoghurts for its health promoting as well as nutritional characteristics. Yet, similar to other lactic acid bacteria, lactobacillus casei encounters a number of stress conditions through industrial processes as well as in the gastrointestinal tract- among which acid stress is an important challenge to its survival. This means that lactobacillus strains including casei are faced with many challenges from the environment and may not survive after all. In some cases, combination of environmental factors may make them harmful altogether.
Attempts to evaluate/appraise cited literature
Besselink et al (2008, p 651-659) cite a publication which claimed to have found higher mortality among persons with acute pancreatitis when treated with strains from bifidobacterium species. In fact, some people questioned the safety of such probiotics as lactobacillus casei. However, a review of the study was conducted and established that- for various reasons- the findings should not make anyone call into question the usefulness of lactobacillus casei and other species. First, it was revealed that the subject in the study were critically ill with a condition that had a mortality rate of up to 30 percent (Besselink et al 2008, p 651-659). In addition, the path of probiotic administration was nasojejunal, rather than oral. In sum, sources that have attemped to disapprove the usefulness and safety of lactobacillus strains have been found to have fundamental flaws as indicated above. In fact, several reserachers have subsequently analyzed such studies and suggested that the high mortality may have been caused by the introduction of enteral solution into the intestine with a huge number of lactic acid-generating bacteria. Worth noting is that fermentation of the enteral nutrition solution via the bacteria may have resulted in the development of semi-solid mass, and lead to bowel ischemia. Besselink et al (2008, p 651-659) notes that the fermented nutrition solution could have remained in the small intestines at the optimal condition with the bacteria without being absorbed. All of this points to a widespread misunderstanding as to the manner in which lactobacillus strains function, thus improving human health.
Other researchers have supported the fact that lactobacillus strains have little or no risk to human health. In fact, Nissen et al (2009, p 290) notes that mucins secreted for intestinal cell membrane are highly complex glycoproteins offering structures as well as viscosity to the mucus layer covering the intestinal epithelial surface. Primarily, this layer is meant to safeguard the underlying cells from such dangers as corrosive gastric acids, invasion by harmful microflora as well as shear forces created by the digestive system. Nevertheless, Nissen et al (2009) claims that probiotic lactic acid bacteria has been evaluated and found to have no ability to corrupt gastric mucin. Indeed, cases of lactic acid bacterial infection are quite rare. The safety associated with strains such as lactobacillus casei and others has been labeled as remarkable given that up to 20 billion administrations are done yearly (Reid and Hammond 2005, p 1491). In sum, as literature indicates, it is evident that lactobacillus strains including casei not only have benefits to human health but also are considered generally safe. The majority of cases questioning safety and usefulness of lactobacillus strains occur in subjects with severely compromised immune status or those with underlying conditions including diabetes, heart disease and other terminal illnesses. In particular, lactobacillus casei found in various food products including yoghurt has been shown to have additional health benefits. Lastly, while some strains of lactobacillus may lead to questions as far as safety is concerned, lactobacillus casei has been found to be quite useful in virtually all environments.
Gap in knowledge identified which could form a project/dissertation
As evidenced in the above literature review, there exists considerable gap in knowledge as far as safety of lactobacillus strains is concerned. In essence, existing studies are yet to link the dots and provide a conclusive report indicating the manner in which such lactobacillus strains as casei lead to improved human health. This also means that different studies often give conflicting findings as evidenced above. For instance, Besselink et al (2008, p 651-659) note cases in which studies want us to believe that some products of lactobacilli- including lactobacillus case- could lead to adverse effects. However, a closer look into the study reviews provided in this paper reveal that lactobacillus strains are rather safe. In fact, the gap in the knowledge is evidenced by studies claiming that lactobacillus species have no detrimental effect whatsoever. This means that humans should consume them is large quantities without the fear that they could affect them in one way or the other. Possibly, this gap, results from the fact that few studies have ventured into investigating the manner in which lactobacillus casei functions, and thus helping humans. In essence, studies are yet to reveal the chemical reactions and or combinations of these strains in humans leading to desired health benefits. nonetheless, this calls for further investigation or projects to test various bifidobacteria-containing products and show how they help improve one’s health.
Specific purpose of your proposed investigation
The purpose of the proposed investigation is to bridge the gap in knowledge specifically by illustrating whether and how lactobacillus casei –and other lactobacillus species- work to improve overall health. In turn, the investigation will provide useful information on whether we should trust lactobacilli-containing products’ safety.
Specific data/information to be investigated identified
Some of the data and or information making up the proposed investigation include strains and growth conditions in which lactobacillus casei, including yoghurt, growth is to be investigated. Investigation the growth of this train is crucial in understanding the manner in which lactobacillus casei influence human health positively. In addition, acid challenge and acid tolerance analysis is to be covered in this investigation to find out the manner in which acids –including those constituting lactic acid bacteria- affect species development and or functioning given different conditions. For instance, using the information, this investigation will seek to establish whether human intestinal conditions could lead to any undesirable effects on the species. As well, information on measurement of epithelial/membrane lateral diffusion will constitute part of the investigation. This will also include investigation of conditions likely to affect the membrane in one way or the other. In addition, fatty acid extraction as well as analysis will form part of the investigation. The information in this part will include a certain technique to identify the manner in which saturation and extraction of fatty acid occurs. Last but not the least, information on examination of inner membrane permeability will be included to assess the permeability through cells. Ultimately, the information will be helpful in revealing lactobacillus species’ functionality in humans and how it leads to improved health.
How will investigation take place? Details of sampling/collection/analysis of data.
The investigation will involve a test involving the effect of lactic acid stress (LAS) on the lactobacillus casei cell membrane as well as its acid resistant mutant (Lbz-2). The test will largely involve data sampling (Cai et al, 2007, p 2655). The two strains lactobacillus casei and acid-resistant mutant will be grown under certain conditions in chemostats. Steady-state chemostat cells –at pH 6.5- will be harvested.
Ethical issues surrounding the proposal
Ethical considerations are usually part of any project, and particularly those involving laboratory tests. In the proposal, cell integrity is crucial in maintaining cell viability as well as metabolic function. For instance, the data analysis and tests will have to ensure that subjects are handled with utmost care to ensure that wastage and stress is minimized. In addition, ethical considerations surrounding the proposal will include honesty and fairness. The two aspects are crucial in ensuring that integrity of the entire project is compromised. In conclusion, lactobacillus casei and other species are known to have myriad benefits to human health. The project will reveal the way lactobacillus species, in particular casei, affect human systems including cell membrane functionality.
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