Method for direct discrimination of intra- and intermolecular hydrogen bonds, and characterization of the G(:A):G(:A):G(:A):G heptad, with scalar couplings across hydrogen bonds

Discrimination of intra- and intermolecular hydrogen bonds in a symmetric multimer has not been accomplished yet, although such discrimination would provide a crucial basis for construction of the multimeric architecture of nucleic acids by NMR. We have developed a direct and unambiguous method for such discrimination involving the use of scalar couplings across hydrogen bonds. The method has been validated with a symmetric dimer of d(GGGCTTTTGGGC), for which the structure including both intra- and intermolecular hydrogen bonds was already reported. This has demonstrated that our method can clearly discriminate these two kinds of hydrogen bonds. Then, the method was applied to a symmetric dimer of d(GGAGGAGGAGGA) and has provided decisive information on its multimeric architecture. Additionally, the values for scalar couplings across hydrogen bonds for G:G and G:A base pairs in the G(:A):G(:A):G(:A):G heptad formed by d(GGAGGAGGAGGA) were determined for the first time. This determination has provided an insight into the nature of the heptad.     

Review: Gastric cancer: Basic aspects

Gastric cancer is still one of the most prevalent and deadliest cancers in the world. Although our knowledge about the disease has progressed extraordinarily, this has not been accompanied by our capacity to effectively treat the disease. In the last years, immunotherapy made its way into the cancer field and was responsible for major changes in the treatment success rates for several cancer types. Although gastric cancer was not among the first successful targets of this type of therapy, the relationship between this type of cancer, immunosurveillance and immunotherapy is now being actively researched. In this article, we review the literature of the past year regarding the relationship between gastric cancer, its immune microenvironment and response to immunotherapy. Published data indicate that the immune microenvironment influences the clinical behaviour of gastric cancer, and is correlated with its histologic and molecular subtypes with an emphasis on the microsatellite‐ and EBV‐positive tumour subgroups. Although the literature regarding response to immunotherapy is scarce, there is good evidence that patient stratification for immunotherapy is going to become a reality in gastric cancer.     

CAMPATH: from concept to clinic

Lymphocyte depletion has a long history in the area of therapeutic immunosuppression. CAMPATH-1H (alemtuzumab) was generated in an attempt to replace anti-lymphocyte globulins in the transplant arena. Its efficacy in killing lymphocytes has established it as a licensed drug for the management of chronic lymphocyte leukaemia. Short-term therapy with alemtuzumab has demonstrated long-term benefit in a number of autoimmune conditions. This drug has the potential to facilitate recruitment of tolerance processes so enabling drug minimization in transplantation, autoimmune and hypersensitivity diseases.     

Perspective: reverse evolution

For some time, the reversibility of evolution was primarily discussed in terms of comparative patterns. Only recently has this problem been studied using experimental evolution over shorter evolutionary time frames. This has raised questions of definition, experimental procedure, and the hypotheses being tested. Experimental evolution has provided evidence for multiple population genetic mechanisms in reverse evolution, including pleiotropy and mutation accumulation. It has also pointed to genetic factors that might prevent reverse evolution, such as a lack of genetic variability, epistasis, and differential genotype-by-environment interactions. The main focus of this perspective is on laboratory studies and their relevance to the genetics of reverse evolution. We discuss reverse evolution experiments with Drosophila, bacterial, and viral populations. Field studies of the reverse evolution of melanism in the peppered moth are also reviewed.     

Growth and development of Encarsia formosa (Hymenoptera: Aphelinidae) in the greenhouse whitefly, Trialeurodes vaporariorum (Homoptera: Aleyrodidae): effect of host age

The tiny parasitoid wasp, Encarsia formosa, has been used successfully to control greenhouse whiteflies (GHWFs) in greenhouses in many countries throughout the world. Therefore, there has been considerable interest in developing methods for artificially rearing this wasp. However, little information is available concerning the regulation of its development including the host-parasitoid interactions that are required for the parasitoid to complete its life cycle. Here we confirm that parasitoid developmental rates differ significantly based upon the host instar parasitized. Development was faster when 3rd and 4th instar GHWFs were offered for parasitization than when 1st or 2nd instars were used. Our results show that it is primarily the embryo and the first two parasitoid instars that exhibit prolonged developmental times when 1st and 2nd instar whiteflies are parasitized. Although percent emergence was not affected by host age at the time of parasitization, adult longevity as well as adult emergence pattern varied greatly depending upon the instar parasitized. When 3rd and 4th instar GHWFs were selected for oviposition, adult wasps lived significantly longer than when 1st or 2nd instars were used; also, there was a sharp emergence peak on the 2nd day after emergence was first observed (reduced or absent when 1st or 2nd instar GHWFs were parasitized) and the emergence period was reduced from between 8 and 11 days to 5 days. In general, the younger the host instar parasitized, the less synchronous was parasitoid development. Previous reports that E. formosa will not molt to the 2nd instar until the host has reached its 4th instar were not confirmed. When 1st instar host nymphs were parasitized, 2nd instar parasitoids were detected in 3rd instar hosts. Importantly, however, no matter which instar was parasitized, the parasitoid never molted to its last instar until the host had reached Stage 5 of its last instar, a stage in which host pharate adult formation has been initiated. It appears, then, that a condition(s) associated with host pharate adult formation is required for the parasitoid's final larval molt. Results reported here should facilitate the development of in vitro rearing systems for E. formosa.     

Computer assisted screening: effect on the patient and his consultation.

The initial impact of computer assisted preventive screening in general practice consultations has been monitored. The technology has not been found stressful by patients, and the power of the consultation to alleviate low arousal has been increased by computer use. No appreciable increase in the durations of consultation was detected, despite an average computer initiated input of two minutes eight seconds. The computer has successfully prompted preventive screening and health education with a sixfold increase in the number of potentially relevant procedures being mentioned. The actual information presented by the computer has been shown to be crucial, with the terminal''s mere presence an ineffective reminder. The computer terminal was used in 65% of the consultations for which it was available, which, if sustained, represents an effective screening programme for attending patients.     

Phylogeography: retrospect and prospect

Phylogeography has grown explosively in the two decades since the word was coined and the discipline was outlined in 1987. Here I summarize the many achievements and novel perspectives that phylogeography has brought to population genetics, phylogenetic biology and biogeography. I also address future directions for the field. From the introduction of mitochondrial DNA assays in the late 1970s, to the key distinction between gene trees and species phylogenies, to the ongoing era of multi-locus coalescent theory, phylogeographic perspectives have consistently challenged conventional genetic and evolutionary paradigms, and they have forged empirical and conceptual bridges between the formerly separate disciplines of population genetics (microevolutionary analysis) and phylogenetic biology (in macroevolution).     

Collagen fibrils: nanoscale ropes

The formation of collagen fibrils from staggered repeats of individual molecules has become "accepted" wisdom. However, for over thirty years now, such a model has failed to resolve several structural and functional questions. In a novel approach, it was found, using atomic force microscopy, that tendon collagen fibrils are composed of subcomponents in a spiral disposition-that is, their structure is similar to that of macroscale ropes. Consequently, this arrangement was modeled and confirmed using elastic rod theory. This work provides new insight into collagen fibril structure and will have wide application-from the design of scaffolds for tissue engineering and a better understanding of pathogenesis of diseases of bone and tendon, to the conservation of irreplaceable parchment-based museum exhibits.     

CREATINE KINASE FROM BRAIN: KINETIC ASPECTS

Abstract— Creatine kinase derived from rabbit brain has been re-examined with respect to its kinetic features. The enzyme from brain has lower Michaelis constants for both ADP and creatine phosphate than does the enzyme from rabbit muscle. Substrate inhibition by excess creatine phosphate occurs at a concentration approximating that found in the tissue. The enzyme from muscle is less sensitive to substrate inhibition.
The crude mitochondrial fraction from rat brain was centrifuged in a sucrose density gradient and the distribution of enzymatic activities among the subfractions was determined. The distribution of creatine kinase resembled that of two glycolytic enzymes; no evidence for a mitochondrial localization was found.     

Timeline: Neurospora: a model of model microbes

In the 1940s, studies with Neurospora pioneered the use of microorganisms in genetic analysis and provided the foundations for biochemical genetics and molecular biology. What has happened since this orange mould was used to show that genes control metabolic reactions? How did it come to be the fungal counterpart of Drosophila? We describe its continued use during the heyday of research with Escherichia coli and yeast, and its emergence as a biological model for higher fungi.     

A Cretaceous crane-fly (Diptera: Tipulidae): 93 million years of stasis

A new fossil species of crane-fly, Helius botswanensis :Diptera: Tipulidaey is described. The specimen was discovered recently in reliably dated. Cretaceous sediments from Botswana. Ii is extremely well preserved, has a distinctive morphology, and is identified as belonging to the extant genus Helius. The single specimen puts the origin of the subfamily Limoniinae and the genus well into the Cretaceous Period, and provides data on the southern African Cretaceous palaeoenvironment. The conservative nature of a dipteran of such antiquity, assignable to an extant genus which has an association with flowers, has implications for evolutionary theory.     

Suicide gene therapy with an adenovirus expressing the fusion gene CD::UPRT in human glioblastomas: different sensitivities correlate with p53 status

BACKGROUND: Several gene therapy strategies have been designed for cancer treatment. Intra-tumoral injection of adenoviruses expressing pro-drug-converting enzymes is one such strategy. Although the efficacy of these therapies was tested in animal models, little work has been devoted to the determination of critical variables for success. In this work, we aimed at better understanding variables that affect the cytosine deaminase::uracil phosphoribosyl transferase (CD::UPRT)-based strategy in two human glioblastomas. METHODS: We have constructed two adenoviruses expressing either CD or the fusion protein CD::UPRT. We have tested their anti-tumor activity in combination with 5-fluorocytosine (5-FC) in the glioblastoma cell lines U87 and U251, which are p53-wt and p53-deficient, respectively. Anti-tumor activity has also been investigated in spheroid structures. RESULTS: The superiority of CD::UPRT over CD was confirmed in both glioblastoma cells. We found that the pro-drug concentration required for anti-tumor activity was 9-fold higher in U251 than in U87, while multiplicity of infection (MOI) as low as 6 was sufficient to achieve 50% killing. Bystander activity was observed with as few as 2 and 6% transduced cells for U87 and U251, respectively. Differences in sensitivity between U87 and U251 were not due to differences in transduction, transgene expression, or intercellular transport, but were related to 5-FU sensitivity and p53 status. Also, it is noteworthy that, in contrast to U87, U251 spheroids barely responded to the treatment, whereas their monolayer counterparts were very sensitive. CONCLUSIONS: Our study has shown that p53 status is important for CD::UPRT/5-FC treatment. Moreover, this study demonstrated that the three-dimensional spheroid model is a more stringent in vitro model for suicide gene therapy evaluation than are monolayer cultures.     

Legionelbacagar: opportunities and prospects

Studies results about characteristics of growth medium for Legionella cultivation--legionelbacagar--are presented in article. It was shown that the medium has good growth characteristics and prolonged shelf life. Successful use of this medium for cultivation of Legionella pneumophila strains isolated during outbreak in Sverdlovsk region in 2007 was demonstrated. Feasibility of its use for isolation of Legionella from environment and clinical samples was discussed.     

Therapy of Chlorpromazine Melanosis: A Preliminary Report

Melanosis observed in association with prolonged chlorpromazine therapy has become a serious problem in mental institutions. Skin pigmentation has produced an appearance which is cosmetically undesirable. Ocular deposits have caused visual impairment. Diffuse visceral involvement has been accompanied by functional disturbances of the involved organs.Withholding chlorpromazine did not diminish the pigment deposits already present in eight patients with chlorpromazine-induced melanosis. Therefore therapy for existing cases and means of preventing this side effect were investigated. A method of blocking melanin synthesis by depressing tyrosinase activity was devised. A copperchelating agent, D-penicillamine, was administered for a period of four weeks (300 mg. three times daily for six days each week, with mineral supplement substituted on the seventh day). Four of six days patients thus treated improved markedly as evidenced by diminution of skin pigmentation. Urinary copper excretion was substantially increased during the trial period. An alternative method of treatment designed to stimulate melatonin production by the pineal gland was employed. Two patients were kept in darkness for a period of four weeks. One improved markedly, the other only slightly.     

Decision-Making Therapy in HIV/AIDS: The African Experience

The challenge of providing relevant and sophisticated counseling interventions to people with HIV/AIDS in Africa has greatly intensified. The task has shifted from what it was deemed to entail at the first decade of the disease. Then, it was understood to involve the process of bringing healing to the emotional situation of the client demoralized by the news of infection. In addition, at that time, the emphasis was on information and education as the most commanding weapon for preventing the spread of the AIDS pandemic. But professional experiences in the second decade of the disease has clearly shown that as we work for prevention we must also develop strategies for responding to the needs and problems of people already in contact with the disease, requiring that they be started on antiviral therapy. The present article is intended to highlight and discuss the critical issues that attend and challenge the decision-making therapy of people with HIV disease in Africa.     

Melanin standard method: particle description.

Melanin isolated from the ink sac of Sepia officinalis (Sepia melanin) has been proposed as a standard for natural eumelanin. There are no standard methods for the isolation, purification, and storage of melanins. Mild methods designed to preserve the native composition and structure of melanin are needed. The specific aim of the present work, using Sepia melanin, was to develop a mild and generally applicable protocol for the isolation and purification of melanins. It is well established that melanin polymers contain a large number of free carboxylic acid residues. These anionic residues are responsible for the cation exchange properties observed for melanins. Heating melanins with hydrochloric acid at reflux has been demonstrated to lead to extensive decarboxylation. Indeed, heat alone has been shown to cause decarboxylation, and care must be exercised to avoid such conditions. By analogy with cation exchange resins, melanins should be isolated and named according to the associated counterion (e.g., Sepia melanin--K+ form). The method reported here avoided extremes in pH and temperature, and was designed to yield melanin in the K+ form. Physical disaggregation of particulate melanin using a wet milling step was also found to facilitate removal of significant quantities of adsorbed protein. The following physical parameters were used to monitor the purification and to characterize the resultant melanin: pH, conductance, particle size, and diffuse reflectance spectroscopy.     

Wake-promoting agents: search for next generation modafinil: part I

In search of a next generation molecule to the novel wake promoting agent modafinil, a series of bi-phenyl derived wakefulness enhancing agents (in rat) was developed. From this work, compound 17 has been selected for additional studies.     

Bio-folio: applying portfolio theory to biodiversity

Genes, species and ecosystems are often considered to be assets. The need to ensure a sufficient diversity of this asset is being increasingly recognised today. Asset managers in banks and insurance companies face a similar challenge. They are asked to manage the assets of their investors by constructing efficient portfolios. They deliberately make use of a phenomenon observed in the formation of portfolios: returns are additive, while risks diversify. This phenomenon and its implications are at the heart of portfolio theory. Portfolio theory, like few other economic theories, has dramatically transformed the practical work of banks and insurance companies. Before portfolio theory was developed about 50 years ago, asset managers were confronted with a situation similar to the situation the research on biodiversity faces today. While the need for diversification was generally accepted, a concept that linked risk and return on a portfolio level and showed the value of diversification was missing. Portfolio theory has closed this gap. This article first explains the fundamentals of portfolio theory and transfers it to biodiversity. A large part of this article is then dedicated to some of the implications portfolio theory has for the valuation and management of biodiversity. The last section introduces three development openings for further research.     

Gene therapy in India: A focus

Gene therapy refers to the treatment of genetic diseases using normal copies of the defective genes. It has the potential to cure any genetic disease with long-lasting therapeutic benefits. It remained an enigma for a long period of time, which was followed by a series of setbacks in the late 1990s. Gene therapy has re-emerged as a therapeutic option with reports of success from recent clinical studies. The United States and Europe has been pioneers in this field for over two decades. Recently, reports of gene therapy have started coming in from Asian countries like China, Japan and Korea. This review focuses on the current status of gene therapy in India.