Naturopathy: a critical appraisal

"Naturopathic medicine" is a recent manifestation of the field of naturopathy, a 19th-century health movement espousing "the healing power of nature." "Naturopathic physicians" now claim to be primary care physicians proficient in the practice of both "conventional" and "natural" medicine. Their training, however, amounts to a small fraction of that of medical doctors who practice primary care. An examination of their literature, moreover, reveals that it is replete with pseudoscientific, ineffective, unethical, and potentially dangerous practices. Despite this, naturopaths have achieved legal and political recognition, including licensure in 13 states and appointments to the US Medicare Coverage Advisory Committee. This dichotomy can be explained in part by erroneous representations of naturopathy offered by academic medical centers and popular medical Web sites.     

The Taguchi methodology as a statistical tool for biotechnological applications: a critical appraisal

Success in experiments and/or technology mainly depends on a properly designed process or product. The traditional method of process optimization involves the study of one variable at a time, which requires a number of combinations of experiments that are time, cost and labor intensive. The Taguchi method of design of experiments is a simple statistical tool involving a system of tabulated designs (arrays) that allows a maximum number of main effects to be estimated in an unbiased (orthogonal) fashion with a minimum number of experimental runs. It has been applied to predict the significant contribution of the design variable(s) and the optimum combination of each variable by conducting experiments on a real-time basis. The modeling that is performed essentially relates signal-to-noise ratio to the control variables in a 'main effect only' approach. This approach enables both multiple response and dynamic problems to be studied by handling noise factors. Taguchi principles and concepts have made extensive contributions to industry by bringing focused awareness to robustness, noise and quality. This methodology has been widely applied in many industrial sectors; however, its application in biological sciences has been limited. In the present review, the application and comparison of the Taguchi methodology has been emphasized with specific case studies in the field of biotechnology, particularly in diverse areas like fermentation, food processing, molecular biology, wastewater treatment and bioremediation.     

Taxonomy and fossils: a critical appraisal

Many compendia at the species, genus and family levels document the fossil record, but these are not standardized, nor usually critical in content, and few are available on the World Wide Web. The sampling of the available record is good for organisms with fossilizable parts, but preservational constraints on the entire morphology, life history and geographical distribution lead to difficulties in recognizing and naming species. We recommend abandoning some of the palaeontological species concepts such as chronospecies and stratospecies, and we advocate species recognition based on unique combinations of characters. The compilation of species lists is extremely time consuming, and given the inherent problems we suggest that compilation of generic lists is a more achievable goal because genera are recognized by definitive morphological characters. In calculating taxon duration, care must be taken to distinguish between mono-, para- and polyphyletic groups, the first being the only reliable unit for use in calculating diversity curves. We support the inclusion of fossils into classifications based on Recent organisms, but we recognize some of the problems this may pose for standard Linnaean classifications. Web-based taxonomy is the way forward, having the advantages of speed and currency of information dissemination, universal access with links to primary literature and increasingly sophisticated imagery. These advantages over conventional outlets will only be realized with careful Web design and a commitment to maintenance.     

Microbial biosynthesis and secretion of l-malic acid and its applications

l-Malic acid has many uses in food, beverage, pharmaceutical, chemical and medical industries. It can be produced by one-step fermentation, enzymatic transformation of fumaric acid to l-malate and acid hydrolysis of polymalic acid. However, the process for one-step fermentation is preferred as it has many advantages over any other process. The pathways of l-malic acid biosynthesis in microorganisms are partially clear and three metabolic pathways including non-oxidative pathway, oxidative pathway and glyoxylate cycle for the production of l-malic acid from glucose have been identified. Usually, high levels of l-malate are produced under the nitrogen starvation conditions, l-malate, as a calcium salt, is secreted from microbial cells and CaCO₃ can play an important role in calcium malate biosynthesis and regulation. However, it is still unclear how it is secreted into the medium. To enhance l-malate biosynthesis and secretion by microbial cells, it is very important to study the mechanisms of l-malic acid biosynthesis and secretion at enzymatic and molecular levels.     

Effectiveness of instruction in critical appraisal (evidence-based medicine) skills: a critical appraisal

OBJECTIVE: To examine the evidence that the teaching of critical appraisal (evidence-based medicine) skills to undergraduate medical students or residents will result in significant gains in knowledge and increased use of the literature in clinical decision-making. DATA SOURCES: Articles published from 1966 to 1995, retrieved through a MEDLINE search supplemented by manual searches; review of bibliographies maintained by individuals involved in teaching critical appraisal skills; and a previous methodological review. STUDY SELECTION: Articles were selected if the study involved some form of control group, although strict randomization was not required, and a measure of performance followed the intervention. Articles were excluded if they simply reported the process of teaching critical appraisal skills or used some form of "happiness index." DATA SYNTHESIS: There were 10 studies of the impact of teaching critical appraisal skills, 6 involving medical students and 4 involving residents. Results from 3 of the studies were nearly uninterpretable and thus were excluded; the remaining 7 were methodologically acceptable. Analysis showed that interventions implemented in undergraduate programs resulted in significant gains in knowledge, as assessed by a written test (mean gain 17.0%; standard deviation [SD] 4.0%). Conversely, studies at the residency level consistently showed a small change in knowledge (mean gain 1.3%; SD 1.7%). Two studies that examined residents'' use of the literature were unable to demonstrate any positive changes. CONCLUSIONS: Studies of the effect of teaching critical appraisal skills on gains in knowledge at the undergraduate level showed consistent improvement. By contrast, changes in knowledge at the residency level were small. Several suggestions from the educational literature are offered to increase effectiveness of critical appraisal interventions.     

The evolution of molluscan photosymbioses: a critical appraisal

Partnerships between animals and photosynthesizing microbes have evolved repeatedly, although their history, adaptations, and ecology remain controversial and little understood. In a critical review of 17 fossil and living clades of shell‐bearing molluscs with photosymbionts (two of them newly inferred), adaptive shell modifications and ecological aspects are discussed in the broader context of photosymbioses in other phyla. Fossil candidates have characteristics that are rare or unknown in living photosymbiotic molluscs, including cementation, porous shell microstructure, and epifaunal habits on carbonate muds. Many ancient photosymbioses may have lived in planktonically more productive environments than are typical of living tropical forms. This may be related to the late appearance (Early Eocene) of the dinoflagellate Symbiodinium, which can thrive under highly oligotrophic conditions. Living photosymbiotic molluscs represent a small and atypical sample of all the photosymbiotic clades that have evolved. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 497–511.     

Comparative biochemistry and physiology in Brazil: a critical appraisal

Brazil stood out as the country with the highest number of submissions to the editorial project dedicated to Latin America by the journal Comparative Biochemistry and Physiology. Therefore, we felt that it was important to critically discuss the state of comparative biochemistry and physiology in this country. Our study is based on data collected from the ISI Web-of-Science. We analyzed publication trends through time, availability of novel approaches and techniques, patterns of collaboration among different geographical regions, patterns of collaboration with researchers abroad, and relative efforts dedicated to the study of biochemical and physiological adaptation of native fauna representing different terrestrial Brazilian biomes. Overall, our data shows that comparative biochemistry and physiology is a lively and productive discipline, but that some biases limit the scope of the field in Brazil. Some important limitations are the very heterogeneous distribution of research nuclei throughout the country and the absence of some important approaches, such as remote sensing and the use of molecular biology techniques in a comparative or evolutionary context. We also noticed that international collaboration far surpasses interregional collaboration, and discuss the possible causes and consequences of this situation. Finally, we found that Brazilian comparative biochemistry and physiology is biome-biased, as the Amazonian fauna has received far more attention than the whole pool of fauna representing other terrestrial biomes. We discuss the possible causes of these biases, and propose some directions that may contribute to invigorate the field in the country.     

Characterization of a key aminoglycoside phosphotransferase in gentamicin biosynthesis

Gentamicin is an aminoglycoside antibiotic obtained from cultures of Micromonospora as the important anti-infective agents. Gentamicin which lacks 3′-hydroxyl group can avoid the attack from the modification enzymes of antibiotic-resistant bacteria in clinic. Consequently, C-3′ dehydroxylation is the key step in gentamicins biosynthesis. We suppose that there are some enzymes responsible for converting intermediate JI-20A to 3′,4′-bisdehydroxylated final product gentamicin C_1a, while phosphorylation of 3′-OH is possibly the first step for C-3′ dehydroxylation. The gentamicin biosynthetic gene gntI, encoding an aminoglycoside phosphotransferase, was cloned from Micromonospora echinospora ATCC15835 and overexpressed in Escherichia coli. The resulting phosphotransferase was purified, and the kinetic parameters for Kanamycin A, Kanamycin B, Neomycin B and Amikacin were determined. Elucidation of NMR data of phosphorylated kanamycin B has unambiguously demonstrated a regiospecific phosphorylation of 3′-hydroxyl of the 6-aminohexose ring. The results described here partly confirm that the 3′-dehydroxylation step is preceded by a 3′ phosphorylation step. It is predicted that GntI belongs to a new aminoglycoside phosphotransferase group involved with aminoglycoside antibiotics biosynthesis pathway.     

Microbial xylanases and their industrial applications: a review

Despite an increased knowledge of microbial xylanolytic systems in the past few years, further studies are required to achieve a complete understanding of the mechanism of xylan degradation by microorganisms and their enzymes. The enzyme system used by microbes for the metabolism of xylan is the most important tool for investigating the use of the second most abundant polysaccharide (xylan) in nature. Recent studies on microbial xylanolytic systems have generally focussed on induction of enzyme production under different conditions, purification, characterization, molecular cloning and expression, and use of enzyme predominantly for pulp bleaching. Rationale approaches to achieve these goals require a detailed knowledge of the regulatory mechanism governing enzyme production. This review will focus on complex xylan structure and the microbial enzyme complex involved in its complete breakdown, studies on xylanase regulation and production and their potential industrial applications, with special reference to biobleaching.     

Using marine macroalgae for carbon sequestration: a critical appraisal

There has been a good deal of interest in the potential of marine vegetation as a sink for anthropogenic C emissions (“Blue Carbon”). Marine primary producers contribute at least 50% of the world’s carbon fixation and may account for as much as 71% of all carbon storage. In this paper, we analyse the current rate of harvesting of both commercially grown and wild-grown macroalgae, as well as their capacity for photosynthetically driven CO₂ assimilation and growth. We suggest that CO₂ acquisition by marine macroalgae can represent a considerable sink for anthropogenic CO₂ emissions and that harvesting and appropriate use of macroalgal primary production could play a significant role in C sequestration and amelioration of greenhouse gas emissions.     

Bacterial alginates: biosynthesis and applications

Alginate is a copolymer of β-d-mannuronic acid and α-l-guluronic acid (GulA), linked together by 1–4 linkages. The polymer is a well-established industrial product obtained commercially by harvesting brown seaweeds. Some bacteria, mostly derived from the genus Pseudomonas and belonging to the RNA superfamily I, are also capable of producing copious amounts of this polymer as an exopolysaccharide. The molecular genetics, regulation and biochemistry of alginate biosynthesis have been particularly well characterized in the opportunistic human pathogen Pseudomonas aeruginosa, although the biochemistry of the polymerization process is still poorly understood. In the last 3 years major aspects of the molecular genetics of alginate biosynthesis in Azotobacter vinelandii have also been reported. In both organisms the immediate precursor of polymerization is GDP-mannuronic acid, and the sugar residues in this compound are polymerized into mannuronan. This uniform polymer is then further modified by acetylation at positions O-2 and/or O-3 and by epimerization of some of the residues, leading to a variable content of acetyl groups and GulA residues. In contrast, seaweed alginates are not acetylated. The nature of the epimerization steps are more complex in A. vinelandii than in P. aeruginosa, while other aspects of the biochemistry and genetics of alginate biosynthesis appear to be similar. The GulA residue content and distribution strongly affect the physicochemical properties of alginates, and the epimerization process is therefore of great interest from an applied point of view. This article presents a survey of our current knowledge of the molecular genetics and biochemistry of bacterial alginate biosynthesis, as well as of the biotechnological potential of such polymers. Received: 14 March 1997 / Received revision: 7 May 1997 / Accepted: 11 May 1997     

The presence of actin in nuclei: a critical appraisal.

To assess the significance of actin associations with nuclei, we have examined Amoeba proteus nuclei for the presence of labeled actin under a variety of circumstances without (in most instances) isolating nuclei or breaking up cytoplasms prior to the extraction of proteins.We first established that: the 42,000 dalton proteins (presumed to be actin) present in cytoplasm and non-isolated nuclei are identical electrophoretically; the putative actin of amebas has the same size and almost the same isoelectric point as rat muscle actin; and the peptide “fingerprints” of putative ameba actin and rat actin are very similar after tryptic digestion. We therefore concluded that the 42,000 dalton protein of ameba is actin.We determined that: the concentrations of actin in the cytoplasm and nucleus of amebas are the same; actin is readily lost from nuclei that are released from lysed cells; shortly after a ³⁵S-labeled nucleus is transplanted into unlabeled cytoplasm, or an unlabeled nucleus is transplanted into ³⁵S-labeled cytoplasm, the concentration of ³⁵S-actin in nucleus and cytoplasm is the same; and when cells containing ³⁵S-actin are subjected to long chase periods on unlabeled food, the concentrations of ³⁵S-actin in nucleus and cytoplasm fall in parallel. These observations taken together suggest that actin is not tightly associated with nuclei. Rather, actin may associate with nuclei for the trivial reason that the nuclear envelope is no barrier to free movement of that protein between the two compartments.We conclude that the mere presence of actin in nuclei is insufficient grounds for assuming that it has any role in nuclear functions, such as, for example, chromosome condensation.     

Microbial processes for ascorbic acid biosynthesis: a review.

L-Ascorbic acid is an important product currently made using the Reichstein process, which is mainly chemical. Recently, bacteria have been identified that are able to transform in a very efficient way glucose to 2,5-keto-D-gluconic acid and this product to 2-keto-L-idonic acid, precursor of L-ascorbic acid. When the corresponding strains are used together, it is possible to get 2-keto-L-idonic acid directly from glucose. Moreover, new strains have been constructed by introducing a gene from a strain responsible for the second step into a strain responsible for the first step. By using one of the new strains, the transformation can be performed in a single step with only one strain. However, the classical process still remains the most competitive.     

Microbial biosynthesis of halometabolites

Halometabolites are compounds that are commonly found in nature and they are produced by many different organisms. Whereas bromometabolites can mainly be found in the marine environment, chlorometabolites are predominately produced by terrestrial organisms; iodo- and fluorocompounds are only produced infrequently. The halogen atoms are incorporated into organic compounds by enzyme-catalyzed reactions with halide ions as the halogen source. For over 40 years haloperoxidases were thought to be responsible for the incorporation of halogen atoms into organic molecules. However, haloperoxidases lack substrate specificity and regioselectivity, and the connection of haloperoxidases with the in vivo formation of halometabolites has never been demonstrated. Recently, molecular genetic investigations showed that, at least in bacteria, a different class of halogenases is involved in halometabolite formation. These halogenases were found to require FADH2, which can be produced from FAD and NADH by unspecific flavin reductases. In addition to FADH2, oxygen and halide ions (chloride and bromide) are necessary for the halogenation reaction. The FADH2-dependent halogenases show substrate specificity and regioselectivity, and their genes have been detected in many halometabolite-producing bacteria, suggesting that this type of halogenating enzymes constitutes the major source for halometabolite formation in bacteria and possibly also in other organisms.