Solid state fermentation for production of α-amylase byBacillus megaterium 16M

Summary The ratio of buffer to wheat bran, incubation temperature and initial pH influence -amylase production byBacillus megaterium 16M under solid state fermentation. The enzyme, with pH and temperature optima at 6.0 and 70°C, is formed at a level of 30,000 units/g dry bacterial bran without coproduction of proteases and cellulases.     

Solid state fermentation for cellulases and β-glucosidase production by Aspergillus niger

Production of cellulases and β-glucosidase was studied using locally-isolated Aspergillus niger on various cheap sources of cellulose like bagasse, corn corbs, computer cards and sawdust, by solid state fermentation (SSF) and by liquid state fermentation (LSF). Enzyme activities were increased about 30–80% by SSF in comparison with conventional LSF. Enzyme production was further improved by various pretreatments, making cellulosic material easily accessible. The best results were obtained with 5 M NaOH treatment.     

Solid state fermentation of straw withNeurospora crassa for CMCase and β-glucosidase production

Summary CMCase and -glucosidase were produced by the mutantNeurospora crassa 40b cultivated on untreated wheat straw in a solid state fermentation. Best enzyme activities were observed when the growth medium was composed of wheat straw mixed with certain mineral solutions at a ratio 1:2 (w/v). A partially purified enzyme preparation showed optimum enzyme activities of CMCase and -glucosidase at pH 4.0 and 5.0 and temperature 50 and 60°C respectively. The apparent Km values for the same enzymes were 16.8 g/l and 1.03x10^–4 M respectively. At optimum growth and enzyme assay conditions yields as high as 586.2 U CMCase and 58.4 U -glucosidase per gram of straw were obtained.     

Marine and estuarine gradients — An overview

The Proceedings of the ECSA 21 symposium on Marine and Estuarine Gradients are reviewed. It is emphasised that this is probably the first time that a full set of papers on the tidal freshwater sections of estuaries has appeared. There is however some ambiguity in the terminology applied to such waters, and a more consistent terminology is proposed. In particular the estuary is defined as reaching upstream as far as the tidal limit, irrespective of salinity. A wide variety of gradients within estuaries and coastal waters are considered, but it is apparent that the crucial spatial gradients are based on salinity, oxygen and turbidity, and that many other gradients are co-variables with these parameters. Temperature is also important for temporal gradients.     

Technology and economics of fermentation alcohol — An update

Fermentation alcohol is being widely studied as an alternative fuel, and production is increasing, especially in Brazil, where the goal is more than 10 billion litres per year by 1985.Fuel markets are hundreds of times greater than the traditional ethanol markets which the existing industry supplies. To make a material contribution to fuel supply, fermentation ethanol must be treated as a major chemical and produced in large-volume, highly efficient plants. Such plants must be assured of a continuous supply of low-cost raw materials for which suitable processes have been developed and commercially proven. Sugar cane in the tropics and grains in some temperate countries meet these requirements; cellulosics do not qualify at present, nor will they in the foreseeable future, without major breakthroughs.Using techniques borrowed from the starch sweetener industry, starchy materials may be economically hydrolysed to fermentable sugars; rapid acid hydrolysis may prove superior to enzymatic processes. Major projects are under way to replace traditional batch or cascade fermentations with rapid, single-vessel continuous units, but these have not yet been fully proven. Where suitable, yeast recycle is being used as a means of increasing alcohol yields, and energy-efficient distillation methods of the petrochemical industry are being adopted. The consequent large reduction in steam consumption greatly reduces the appeal of other methods which have been proposed to remove water.Opportunities for process improvements abound, especially in developing (1) the means to provide cellulosic raw materials in large quantities at acceptable costs, (2) economically effective methods of pretreating and hydrolysing cellulosics, (3) practical organisms for converting five-carbon sugars to ethanol and (4) higher fermentation yields and efficiencies using bacteria or immobilized yeast.     

Solid state fermentation for the production of α-amylase from Penicillium chrysogenum using mixed agricultural by-products as substrate

Production of α-amylase from local isolate, Penicillium chrysogenum, under solid-state fermentation (SSF) was carried out in this study. Different agricultural by-products, such as wheat bran (WB), sunflower oil meal (SOM), and sugar beet oil cake (SBOC), were used as individual substrate for the enzyme production. WB showed the highest enzyme activity (750 U/gds). Combination of WB, SOM, and SBOC (1:3:1 w/w/w) resulted in a higher enzyme yield (845 U/gds) in comparison with the use of the individual substrate. This combination was used as mixed solid substrate for the production of α-amylase from P. chrysogenum by SSF. Fermentation conditions were optimized. Maximum enzyme yield (891 U/gds) was obtained when SSF was carried out using WB + SOM + SBOC (1:3:1 w/w/w), having initial moisture of 75%, inoculum level of 20%, incubation period of 7 days at 30°C. Galactose (1% w/w), urea and peptone (1% w/w), as additives, caused increase in the enzyme activity.     

An overview of the multispecies VPA — theory and applications

Summary Multispecies virtual population analysis is an attempt to take species interactions into account when assessing the status of fish stocks. It was introduced primarily with the aim of lowering the uncertainty in the natural mortality rate as used in single species VPA and to take account of variability between years and ages by calculating inside the model the part of the mortality rate caused by predation. The output of the MSVPA is therefore —in addition to stock sizes and fishing mortality rates as in single species VPA —the amounts consumed of the various species by the predators included in the analysis.The MSVPA model of the predation interactions results in a set of coupled non-linear equations which must be solved for each time step in the analysis. Key parameters in the model are the so-called suitability coefficients, measuring the relative suitability of one species as prey for another species. These parameters must be estimated inside the model and this estimation requires data on the stomach contents of the predators in the model. The MSVPA makes two key assumptions: constant ration size (i.e. independent of time for each species-age combination) and hence fixed weights-at-age and a model of prey selection which leads to a type ii functional feeding response. These assumptions do not hold for all areas and therefore limit the applicability of the MSVPA in its present form.The MSVPA is probably one of the more successful multispecies models in fisheries. Its main application to date has been to the North Sea, and although it has not been used directly as a management tool it has provided input values of parameters used in assessment models as well as valuable insights into the system. For example, it has demonstrated that an increase in mesh size can result in lower long-term yields, an effect opposite to what is predicted if species interactions are ignored. Such insights into the dynamics of the system are useful and MSVPA may therefore have an indirect role to play in management. Nevertheless, due to many uncertainties involved in multispecies modelling in general and MSVPA in particular, it seems doubtful that the use of MSVPA in fisheries management will be much greater in the immediate future than it is at present.     

Polyphasic approach of bacterial classification — An overview of recent advances

Classification of microorganisms on the basis of traditional microbiological methods (morphological, physiological and biochemical) creates a blurred image about their taxonomic status and thus needs further clarification. It should be based on a more pragmatic approach of deploying a number of methods for the complete characterization of microbes. Hence, the methods now employed for bacterial systematics include, the complete 16S rRNA gene sequencing and its comparative analysis by phylogenetic trees, DNA-DNA hybridization studies with related organisms, analyses of molecular markers and signature pattern(s), biochemical assays, physiological and morphological tests. Collectively these genotypic, chemotaxonomic and phenotypic methods for determining taxonomic position of microbes constitute what is known as the ‘polyphasic approach’ for bacterial systematics. This approach is currently the most popular choice for classifying bacteria and several microbes, which were previously placed under invalid taxa have now been resolved into new genera and species. This has been possible owing to rapid development in molecular biological techniques, automation of DNA sequencing coupled with advances in bioinformatic tools and access to sequence databases. Several DNA-based typing methods are known; these provide information for delineating bacteria into different genera and species and have the potential to resolve differences among the strains of a species. Therefore, newly isolated strains must be classified on the basis of the polyphasic approach. Also previously classified organisms, as and when required, can be reclassified on this ground in order to obtain information about their accurate position in the microbial world. Thus, current techniques enable microbiologists to decipher the natural phylogenetic relationships between microbes.     

Interdisciplinary integration in biology? An overview

Philosophical theories about reduction and integration in science are at variance with what is happenign in science. A realistic approach to science show that possibilities for reduction and integration are limited. The classical ideal of a unified science has since long been rejected in philosophy. But the current emphasis on interdisciplinary integration in philosophy and in science shows that it survives in a different guise. It is necessary to redress the balance, specifically in biology. Methodological analysis shows that many of the grand interdisciplinary theories involving biology actually represent pseudo-integration covered up by inappropriate, overgeneral concepts. Integrationism is not bad, but it must be kept within reasonable bounds. If the present analysis is appropriate, there will have to be fundamental changes in research strategy both in science and in the philosophy of science.     

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.     

An overview on 5α-reductase inhibitors

Benign prostatic hyperplasia (BPH) is the noncancerous proliferation of the prostate gland associated with benign prostatic obstruction and lower urinary tract symptoms (LUTS) such as frequency, hesitancy, urgency, etc. Its prevalence increases with age affecting around 70% by the age of 70 years. High activity of 5α-reductase enzyme in humans results in excessive dihydrotestosterone levels in peripheral tissues and hence suppression of androgen action by 5α-reductase inhibitors is a logical treatment for BPH as they inhibit the conversion of testosterone to dihydrotestosterone. Finasteride (13) was the first steroidal 5α-reductase inhibitor approved by U.S. Food and Drug Administration (USFDA). In human it decreases the prostatic DHT level by 70-90% and reduces the prostatic size. Dutasteride (27) another related analogue has been approved in 2002. Unlike Finasteride, Dutasteride is a competitive inhibitor of both 5α-reductase type I and type II isozymes, reduced DHT levels >90% following 1 year of oral administration. A number of classes of non-steroidal inhibitors of 5α-reductase have also been synthesized generally by removing one or more rings from the azasteroidal structure or by an early non-steroidal lead (ONO-3805) (261). In this review all categories of inhibitors of 5α-reductase have been covered.     

β-Glucosidase production by Aspergillus phoenicis in solid state fermentation

Summary -glucosidase production was studied in solid-state cultivation by Aspergillus phoenicis on sugar beet pulps. The experiments were carried out in column incubators aerated with humidified air, at 30 °C. Results of physiological studies showed that the production of -glucosidase from beet pulps in the solid state fermentation required : 70% moisture content, initial pH of about 4, and 10⁷ spores/g substrate. -glucosidase produced under these conditions could be removed from the solid medium with water, or stored in the form of a dried fermented product, for a direct use in the saccharification reactions.     

Bolboforma — an overview

A summary of the present knowledge ofBolboforma is presented in this paper. The genusBolboforma contains a diverse group of marine, mostly single-chambered enigmatic microfossils (phytoplankton, possibly Chrysophyta) which produced calcitic monocrystalline spheroidal tests with or without inner cysts and with various types of ornamentation. The genusBolboforma occurs in the time interval between late Early Eocene to Late Pliocene, at middle and higher latitudes, and thus, has not been recorded in Quaternary to Recent Sediments. The genus is represented globally, but the first and the last occurrence of the genus appear to be spatially diachronous in both hemispheres.Bolboforma started in the southern hemisphere at the Campbell Plateau (SW Pazific) during the Early Eocene approximately 53 Ma ago, and the genus lived there until latest Miocene times (5.3 Ma at the Kerguelen Plateau, Southern Indian Ocean). The first occurrence ofBolboforma in the northern hemisphere is observed in Upper Eocene Sediments (ca. 36.5 Ma) in the Labrador Sea (North Atlantic), and its youngest occurrence is observed in the Hatton-Rockall Basin (North Atlantic) in the Late Pliocene at 2.84 Ma. Well established and common species permit the definition of nineteenBolboforma zones/subzones. Not all of these are observed in both hemispheres. In the southern hemisphere all four Paleogene zones, but only eight Neogene zones are present, in the northern hemisphere only one Paleogene zone, but fourteen Neogene zones have been determined. Bolboforma distribution, which appears to be broadly bipolar in temperate to cool regions at middle to higher latitudes, aso seems to be linked to the evolution of surface watermasses and their boundaries.      

An editorial overview： HIV/AIDS in China

China has come a long way in fighting against HIV/AIDS epidemic. The Chinese government has taken an active role in combating this detrimental disease and such a welcome attitude by the Chinese government will certainly provide a positive spin on its effort in reducing the HIV/AIDS epidemic in China.     

Stereochemical facets of clinical β-blockers: An overview

The modern β-adrenergic agonists (β-blockers) possess one or more than one chiral center in their structure. Two enantiomers exhibit distinct pharmacodynamic and pharmacokinetic behaviors. Current progress in drug designing has resulted in the ability to understand the role of chirality in modern therapeutics. Furthermore, with a greater understanding of the molecular structure of precise drug targets, development of new drugs is directed towards the pure enantiomers instead of its racemates. The present review deals with a discussion on the stereochemical facets of chiral clinical β-blockers. This review provides details of stereo-selectivity in the pharmacological behavior of some of β-blockers and their metabolites. An effort has been made on highlighting the distinction between the therapeutic behavior of the racemic mixtures and pure enantiomers.     

Cytokinins and auxins in plant-pathogen interactions – An overview

Alterations in plant development are frequently observed following pathogen infection. Infection by virus frequently results in stunting of growth, and the chlorosis and abscission of leaves; infection by fungi is often notable for green island formation and growth malformations; and infection by some bacteria results in the formation of galls. While the area of plant-pathogen interactions is currently receiving considerable attention and some plant-pathogen interactions are well characterised with both cytokinins and auxins being implicated (infection by Agrobacterium tumefaciens being the obvious example), there has been relatively little published in the recent literature pertaining to the involvement of cytokinins and auxins in viral, fungal and other forms of bacterial pathogenesis. This overview focuses on what is known concerning the strategies utilised by gall-forming bacteria, and fungal and viral phytopathogens to manipulate the endogenous cytokinin and/or auxin content of their host plant.