Insects in agroecosystems – an introduction

Agroecology is the study of linkages in agricultural systems and it derives from the need to understand and restore natural connections and ecological complexity to control insect and other pest populations. The present special issue addresses a rich variety of agroecosystems spanning the globe, involving the roles of a range of insects on a great many crops. The overview will further improve our understanding of the complex ecology of the players and the ecological complexity of the crop systems.     

Aquaporins in development – a review

Water homeostasis during fetal development is of crucial physiologic importance. It depends upon maternal fetal fluid exchange at the placenta and fetal membranes, and some exchange between fetus and amniotic fluid can occur across the skin before full keratinization. Lungs only grow and develop normally with fluid secretion, and there is evidence that cerebral spinal fluid formation is important in normal brain development. The aquaporins are a growing family of molecular water channels, the ontogeny of which is starting to be explored. One question that is of particular importance is how well does the rodent (mouse, rat) fetus serve as a model for long-gestation mammals such as sheep and human? This is particularly important for organs such as the lung and the kidney, whose development before birth is very much less in rodents than in the long-gestation species.     

Prebiotic Syntheses Under Shock in the Water – Formamide – Potassium Bicarbonate – Sodium Hydroxide System

Origins of Life and Evolution of Biospheres - Syntheses under shock in nitrogen bubbled samples of the water – formamide – bicarbonate – sodium hydroxide system at...     

Hyperthermia in cervical cancer – current status

BackgroundThis article reviews the salient features of recent results of clinical studies. It puts a special emphasis on technical aspects, mechanisms of action together with radiotherapy and chemotherapy and points out areas for additional investigation.AimTo present the current state of knowledge on hyperthermia (HT) and to highlight its role in the treatment of cervical cancer.Materials and methodsThe literature on the clinical use of combined hyperthermia for cervical cancer was analyzed. Clinical outcomes together with the technical aspects and the role of HT were also evaluated.ResultsClinically randomized trials have demonstrated benefit including survival with the addition of hyperthermia to radiation or chemotherapy in the treatment of cervical cancer without significant acute or late morbidities. The technological advances have led to an effective and safer treatment delivery, thermal treatment planning, thermal dose monitoring and online adaptive temperature modulation.ConclusionsDue to rapid development over the last decade of hyperthermia systems and new studies at the basic science and clinical level, the perception of hyperthermia as a part of multimodality treatment in cervical cancer has been changed. However, there is still a need for multicentre randomized clinical trials.     

Artemisietea vulgaris in Romania – An overview

This paper summarizes present knowledge of the synanthropic nitrophilous communities dominated by tall herbs on the basis of the present Artemisietea vulgaris database. Floristic variability was examined also in detrended correspondence analysis. Each cluster was inspected for its ecological and floristic consistency. The final interpretable solution comprises five clusters. Species to clusters fidelity was calculated using ? coefficient. The ecological interpretation of the five groups was based on the average Pignatti indicator values. Groups were compared by using Tukey's honest significant difference test in conjunction with ANOVA. Finally, based on the statistical analysis, we established five alliances: Onopordionacanthii, Matricario-Chenopodion, Dauco-Melilotion, Arctionlappae, and Convolvuloarvensis-Elytrigionrepenti.     

Trends in inulinase production – a review

This article highlights the research work carried out in the production of inulinases from various inulin substrates using strains of bacteria, yeast and fungi. Inulin is one of the numerous polysaccharides of plant origin that contains glucose or fructose. It is used as a substrate in industrial fermentation processes and in food industries due to its relatively cheap and abundant source for the microbiological production of high-fructose syrups, ethanol and acetone–butanol. The various oligosaccharides derived from inulin also find their application in the medical and dietary sector. The inulinase acts on the β-(2,1)-D-fructoside links in inulin releasing D-fructose. Hence, this article illustrates the capability of various microbes in hydrolyzing the carbon at its optimum nutrient concentration and operating condition towards inulinase production.     

Growth in Crustacea – twenty years on

Developments during the past 20 years are reviewed for four aspects of crustacean growth. These are the hormonal control of moulting, the effects of external factors on growth rate, the patterns of growth and the determination of age. Hormonal control. The nature and structure of Moult Inhibiting Hormone has been determined, though the mechanism by which it inhibits crustecdysone production is still unclear. A role in moult control by Crustacean Hyperglycaemic Hormone has been demonstrated, but needs clarification. Methyl farnesoate, a juvenile hormone like substance, occurs in Crustacea: however, a clear function as a juvenile hormone has yet to be shown. External factors. The effect of increased temperature in reducing moult increments is supported by further data. Reduced food supply causes smaller moult increments and longer intermoult periods: the latter effect is generally proportionately greater. A role for CHH in this process is hypothesised. Patterns of growth. Little advance has occurred in understanding the rationale for the diversity of growth patterns. Computer modelling offers promise, but is constrained by lack of data on natural mortality for validation. Determination of age. The basic methods available remain size frequency analysis and tagging programmes. There have been advances in technology and methods of analysis, but no major breakthrough. Novel methods include radionuclide ratios (expensive, complex and give only duration of current intermoult), lipofuschin pigment assay (promising, but needs further validation), and annular structures in the infra-cerebral organ (still very speculative).     

Potassium in agriculture – Status and perspectives

In this review we summarize factors determining the plant availability of soil potassium (K), the role of K in crop yield formation and product quality, and the dependence of crop stress resistance on K nutrition. Average soil reserves of K are generally large, but most of it is not plant-available. Therefore, crops need to be supplied with soluble K fertilizers, the demand of which is expected to increase significantly, particularly in developing regions of the world. Recent investigations have shown that organic exudates of some bacteria and plant roots play a key role in releasing otherwise unavailable K from K-bearing minerals. Thus, breeding for genotypes that have improved mechanisms to gain access to this fixed K will contribute toward more sustainable agriculture, particularly in cropping systems that do not have access to fertilizer K. In K-deficient crops, the supply of sink organs with photosynthates is impaired, and sugars accumulate in source leaves. This not only affects yield formation, but also quality parameters, for example in wheat, potato and grape. As K has beneficial effects on human health, its concentration in the harvest product is a quality parameter in itself. Owing to its fundamental roles in turgor generation, primary metabolism, and long-distance transport, K plays a prominent role in crop resistance to drought, salinity, high light, or cold as well as resistance to pests and pathogens. Despite the abundance of vital roles of K in crop production, an improvement of K uptake and use efficiency has not been a major focus of conventional or transgenic breeding in the past. In addition, current soil analysis methods for K are insufficient for some common soils, posing the risk of imbalanced fertilization. A stronger prioritization of these areas of research is needed to counter declines in soil fertility and to improve food security.     

The use of charcoal in in vitro culture – A review

Activated charcoal is commonly used in tissue culture media. Its addition to culture medium may promote or inhibit in vitro growth, depending on species and tissues used. The effects of activated charcoal may be attributed to establishing a darkened environment; adsorption of undesirable/inhibitory substances; adsorption of growth regulators and other organic compounds, or the release of growth promoting substances present in or adsorbed by activated charcoal.     

What is truth – in science and beyond

Truth is threatened in our societies and one might wish that scientists should stand up for truth, but in order to do so, one needs to know what is truth and how it can be recognized. The oldest and most widely accepted concept of truth is the Correspondence Theory requesting a fit of propositions and reality. In the Coherence Theory truth is a consistent property of a whole system of propositions. In the Pragmatic Theory truth works in practical terms. Scientists have defined criteria to verify true statements by experiments and by the simplicity of theories. Aristotle proposed parsimony claiming the superiority of theories which derive from fewer hypotheses. David Hume suggested probability arguments to assess the force of evidence. Nicolai Hartmann elaborated a model based on the congruence of a priori logical arguments with a posteriori empirical observations. Karl Popper introduced the falsification of testable theories as a way to better theories. The analysis shows that scientific and medical research uses classical philosophical criteria of truth in their daily work. Humanities use different, hermeneutic criteria of truth. Finally, societies need for their coherence a dialectic approach to truth based on honest discussion of opposing views.     

Bioinformatics in microbial biotechnology – a mini review

The revolutionary growth in the computation speed and memory storage capability has fueled a new era in the analysis of biological data. Hundreds of microbial genomes and many eukaryotic genomes including a cleaner draft of human genome have been sequenced raising the expectation of better control of microorganisms. The goals are as lofty as the development of rational drugs and antimicrobial agents, development of new enhanced bacterial strains for bioremediation and pollution control, development of better and easy to administer vaccines, the development of protein biomarkers for various bacterial diseases, and better understanding of host-bacteria interaction to prevent bacterial infections. In the last decade the development of many new bioinformatics techniques and integrated databases has facilitated the realization of these goals. Current research in bioinformatics can be classified into: (i) genomics – sequencing and comparative study of genomes to identify gene and genome functionality, (ii) proteomics – identification and characterization of protein related properties and reconstruction of metabolic and regulatory pathways, (iii) cell visualization and simulation to study and model cell behavior, and (iv) application to the development of drugs and anti-microbial agents. In this article, we will focus on the techniques and their limitations in genomics and proteomics. Bioinformatics research can be classified under three major approaches: (1) analysis based upon the available experimental wet-lab data, (2) the use of mathematical modeling to derive new information, and (3) an integrated approach that integrates search techniques with mathematical modeling. The major impact of bioinformatics research has been to automate the genome sequencing, automated development of integrated genomics and proteomics databases, automated genome comparisons to identify the genome function, automated derivation of metabolic pathways, gene expression analysis to derive regulatory pathways, the development of statistical techniques, clustering techniques and data mining techniques to derive protein-protein and protein-DNA interactions, and modeling of 3D structure of proteins and 3D docking between proteins and biochemicals for rational drug design, difference analysis between pathogenic and non-pathogenic strains to identify candidate genes for vaccines and anti-microbial agents, and the whole genome comparison to understand the microbial evolution. The development of bioinformatics techniques has enhanced the pace of biological discovery by automated analysis of large number of microbial genomes. We are on the verge of using all this knowledge to understand cellular mechanisms at the systemic level. The developed bioinformatics techniques have potential to facilitate (i) the discovery of causes of diseases, (ii) vaccine and rational drug design, and (iii) improved cost effective agents for bioremediation by pruning out the dead ends. Despite the fast paced global effort, the current analysis is limited by the lack of available gene-functionality from the wet-lab data, the lack of computer algorithms to explore vast amount of data with unknown functionality, limited availability of protein-protein and protein-DNA interactions, and the lack of knowledge of temporal and transient behavior of genes and pathways.     

Hatching glands in cephalopods – A comparative study

Hatching of embryos from their eggs involves either mechanical and/or chemical support. In particular enzymes are widely used in the animal kingdom to weaken the egg layers and facilitate the embryo's escape. Although numerous morphological and biochemical studies exist on the hatching glands of invertebrates (such as sea urchins, ascidians, insects) and vertebrates (teleosts, amphibians, and mammals), little is known about the morphology of the hatching glands (Hoyle organs) in cephalopod hatchlings.In this study, the internal gland structure and the external appearance of the Hoyle organ are compared among several cephalopod species (Idiosepius pygmaeus; Euprymna scolopes; Sepia officinalis; Loligo gahi; Sepioteuthis lessoniana; Architeuthis sp.; Octopus vulgaris; Tremoctopus gracilis; Argonauta hians). In almost all cases the glandular system is restricted to the posterior part of the dorsal mantle surface. Only Octopus and Argonauta lack a specific glandular structure in this body region and the animals apparently use other mechanisms to penetrate the egg layers.In all decapod species (Idiosepius; Euprymna; Sepia; Loligo; Sepioteuthis; Architeuthis) as well as in Tremoctopus only one specific cell type is present in the Hoyle organ, which synthesizes granular material. The secretory droplets are more or less uniform in electron density in Idiosepius, Euprymna and Tremoctopus but exhibit translucent inclusions in the other decapods. The time of gland development, first synthesis of secretory products and later degeneration after hatching vary between the species.The present study contributes to our knowledge of glandular systems in cephalopods and allows comparison with hatching structures in other invertebrates and vertebrates.     

Saponins in Tribulus terrestris – Chemistry and Bioactivity

Tribulus terrestris is a valuable herb known for its application in the folk medicine in many parts of the world. Furostanol and spirostanol saponins of tigogenin, neotigogenin, gitogenin, neogitogenin, hecogenin, neohecogenin, diosgenin, chlorogenin, ruscogenin and sarsasapogenin type are frequently found in this plant. Four sulphated saponins of tigogenin and diosgenin type are also isolated. Extracts and steroidal saponins have been found to possess various pharmacological activities. Preparations based on the saponin fraction of T. terrestris are used for treatment of infertility and libido disorders in men and women, as well as for treatment of cardiac diseases. Food supplements containing T. terrestris extracts are on sale in USA and Europe with claim of a general stimulating action. In this review the steroidal saponins found in T. terrestris are presented, covering the literature up to 2004. The data reveal clear difference in the saponin composition of samples from this plant species collected from different geographical regions. A comprehensive account on the biological activity of extracts and individual saponins is also included.     

Bioclimatic conditions in Mexico City – an assessment

 Bioclimatic conditions have been assessed for a large urban area located in the tropical highlands of central Mexico using the indices (in °C) of resultant temperature (RT) and effective temperature (ET). The well-developed heat island effect the city generates, reduces the number of nights categorized as cold (ET between 5 and 15° C) to cool (ET from 15 to 18.5° C). Most days fall in the cold to cool range and during the warm season (April to June) the bioclimate of Mexico City is mostly within the neutral (comfort) range. The effect of the nocturnal (to the west) and daytime (to the east of the town) heat island is noticeable in the central and northern sectors. The daytime heat island located in these regions, albeit small (urban air temperature 2–3° C greater than rural), compared with the nocturnal heat island intensity (9–10° C) still adds energy to the already heated afternoon urban air. ET values in the north and central sectors approach the threshold for comfort (ET of 25° C) during the warm months around noon. It is not surprising to find that as the nocturnal heat island has increased over the years (1921–1985) as the city grew, so has the ET for the central district and indicating the dominating role of temperature in the ET index. Assessment of the diurnal cycle of bioclimatic conditions in downtown Mexico City by means of two empirical indices (effective temperature and thermopreferendum) throughout the years gave similar results to those obtained from the application of Fanger’s predicted mean vote (PMV) model. An attempt has been made to characterize four bioclimatic zones in the capital city. Received: 8 March 1994 / Revised: 15 July 1996 / Accepted: 9 September 1996     

Elefantenhaltung in Europa und Indien – ein Vergleich

In none of the countries of origin Asian elephants are taken any more from the wild. Instead breeding stations arise. In India the methods of keeping elephants have become subject of scientific investigations. As a result elephants in the long run will be allowed to be held only in forest camps. The concepts of elephant husbandry are discussed and developed also outside the countries of origin. Under consideration of their biological, ecological and social requirements elephants have to be managed in groups. It is the author's opinion that protected contact will be the method of the future.