bluuebunny/crossref_metadata_2025 huggingface dataset:
1992 from the perspective of the UK food manufacturer
Authors: PICKLES LES
Published: October 2007

According to a recent survey*, ‘British companies are not perceived to be a major threat by rival European firms. In contrast, the UK is a heavily targeted market for foreign companies’.

Real expenditure on food is increasing but at a lower rate than total consumer spending. Food expenditure as a percentage of total consumer spending has dropped to 14% in the UK. This is the lowest of any European country but still a few points higher than in the USA.

Expenditure on food consumed outside the home is also increasing at a much faster rate than expenditure on food for consumption at home. This type of expenditure now amounts to 30% (much less in terms of the quantity of food consumed, of course) of consumer spending, compared with 45% in the USA and is still growing.

Within household food consumption, an increasing proportion of expenditure is going on convenience products.

Throughout Europe similar trends are apparent — increased opportunities for prepared products offering high quality, high nutritional value, freshness' and convenience. The balance between the various attributes most valued by consumers has varied over time within countries and differs between countries at any given time.

The UK is one of the most developed markets in terms of expenditure on convenience foods, ownership of freezers and microwave ovens. (Fig. 1) This provides home companies with a large base from which to export and an attractive target for continental companies looking for diversification from staple products.
1992 The impact on farming
Authors: HAWORTH MARTIN
Published: October 2007

Agriculture has been subject to European influence via the Common Agricultural Policy since 1962. Goods like grain and milk already circulate relatively freely in Europe. Transport of goods will benefit from the lifting of restrictions and the opening of the Channel Tunnel. The removal of monetary Compensatory Amounts will benefit British farmers if currency fluctuations are removed. The abolition of frontier health checks on plants and animals in favour of checks by exporting countries is alarming, but experts are confident about the prospects of greatly reducing the incidence of serious disease. The impact of 1992 on farming will be slight compared with the effect on the food industry. The question is will 1992 bring an efficient low‐cost food industry on the American model or will Europe's diversify be retained?
Meeting the challenges for the UK Food and Drink Industry in a single European Market
Authors: GALAMA KEITH
Published: October 2007

The removal of barriers to trade will generate ‘marketing wars’ in which profits will come from value added products of high controlled quality. Investments must be made in understanding the new markets and finding marketing niches. Specialist products will benefit from the economies of scale in manufacturing for an enlarged market.
n‐3 fatty acids and coronary heart disease Epidemiology from Eskimos to Western populations
Authors: KROMHOUT D.
Published: October 2007

The original cross‐cultural comparisons between Greenland Eskimos and Danes and between Japan and Western countries suggested that a high fish intake was associated with low mortality rates from coronary heart disease. More comprehensive cross‐cultural studies, eg the Seven Countries Study showed that the saturated fat content of the diet is more important than the amount of fish in explaining differences in coronary heart disease mortality between countries. Cohort studies carried out in cultures with a low level of fish consumption showed that persons who eat fish once or twice a week had lower mortality rates from coronary heart disease than persons who did not eat fish. The results of the epidemiological studies carried out so far suggest that a diet low in saturated fat in combination with a low level of fish consumption may be of importance for coronary heart disease prevention.
Structure and texture — their importance in food quality
Authors: KILCAST DAVID , LEWIS DAVID F.
Published: October 2007

Texture is important in determining the eating quality of foods and can have a strong influence on food intake and nutrition. Perceived texture is closely related to the structure and composition of the food, and both microscopic and macroscopic levels of structure can influence texture. A complete description of food texture can only be achieved using sensory methods, but difficulties associated with such methods have led to the development of rapid, inexpensive but less satisfactory instrumental methods. New techniques based on instrumental measurement made on human subjects during chewing promise to open up a new understanding of food texture.
Oxygen radicals in living systems and in food
Authors: DONNELLY JUDITH K. , ROBINSON DAVID S.
Published: October 2007

Oxygen‐derived free radicals are produced both within cells of living systems and in fresh and processed foods by electron transfer reactions usually catalysed by enzymes or transition metal ions, or by ultraviolet or other types of radiation. The production of free radicals is a normal biochemical event, but if reactive radicals are allowed to come into contact with susceptible molecules this may result in damage, e.g. to DNA, enzymes and other proteins, as well as polyunsaturated fatty acids (PUFA) in cell membranes. Reactive free radicals cause deterioration of the nutritional value of foods through free radical chain reactions which may also be responsible for the alteration of the colour and flavour of food. The deleterious action of free radicals in living tissue and during the storage or processing of fresh foods may be prevented by their rapid conversion to non‐radical (stable) products; this may occur through radical‐radical interactions or by the action of antioxidants.
Observations on Bovine Spongiform Encephalopathy
Authors: SYMONDS HERB
Published: October 2007

Public concern over bovine spongiform encephalopathy, or BSE, stems from the fear that, because the disease is transmissible between some animal species there may be a potential risk to man from the consumption of beef. It cannot be claimed that there is no risk to man because the information necessary to make such a statement is not yet available. However there is considerable evidence which indicates that the potential risk to man is very low. This article reviews the evidence from laboratory and epidemiological studies on both animal and human encephalopathies.
Myco‐protein —a new food
Authors: SADLER MICHÈLE
Published: October 2007

Until recently the main contribution of micro‐organisms to the human diet has been through fermentation, which is the basis of many traditional foods and drinks. The successful production of myco‐protein marks a new role in the diet for microfungi, and is a good example of the modern application of biotechnology to food production.
Calcium
Authors: HALLIDAY ANNE
Published: October 2007

Calcium is the most abundant mineral in the body and has important structural and metabolic roles. In the average British diet, milk and other dairy products and fortified white bread provide the major supply. The average intake in the UK is well above the current recommended daily amount although the intakes of some school girls are quite low and may be a cause for concern. The amount of calcium which is absorbed and excreted is affected by a number of dietary and physiological factors. The plasma ionized calcium concentration is maintained by the concerted action of 3 hormones, parathyroid hormone, vitamin D and calcitonin. Dietary calcium has been implicated in the development of osteoporosis through failure to achieve an adequate peak base mass during early years or an increased rate of bone loss in later life. The first possibility has not yet been addressed and the second has not yet been resolved. Calcium requirements are difficult to determine confidently and further research on the relationship between calcium and the attainment of peak bone mass in early life and of the ability of individuals to adapt to different calcium intake is needed.
Diet and cancer — experimental evidence
Authors: CONNING DAVID M.
Published: October 2007

There is much evidence that nutrients can influence the outcome of studies of carcinogenesis in experimental animals. At present, much of the information is contradictory and of uncertain relevance to man. This is because different nutrients appear to affect different stages of the cancerous process and there may be many interactions between the nutrients, and between the nutrients and the cancer‐causing agents. It is unlikely that such agents will ever be entirely eliminated from the human diet but there is a real possibility that several classes of nutrients have a protective effect.
Thirty foods a day — is this the well‐balanced way?
Authors: MATSUMURA MACHIKO , RYLEY JANICE
Published: October 2007

It is 35 years since the Japanese diet started to show the effects of increased availability of milk and meat products but there are still major differences in the food and nutrient composition of the Japanese and UK diets. The Japanese now live longer than the British with only a third of the UK death rate from heart disease and a little more than half the UK death rate from cancer. Notwithstanding the problems inherent in comparing national statistics and the hazards of interpreting epidemiological correlations, such major differences remain thought provoking.
Food for thought — hindsight in history
Authors: SEAMAN ALAN
Published: October 2007

The Emperor Tiberius asked what song the Sirens sang. Sir Thomas Browne cautiously said this was ‘not beyond all conjecture’. In recent times scientists have applied their specialities to conjecture on historic events and peoples. Famous people attract such attention and in some cases their death or illness may be food related. Ten such cases are presented here.
Quality, safety and choice: a European food policy for the 1990s
Authors: SAUNDERS BARBARA
Published: October 2007

The European Community is fortunate to have sufficient food to be able to address the issues of quality, safely and choice rather than sufficiency alone. When the EC was founded in 1958, agricultural issues dominated, with the need to secure a regular supply of food high on the political agenda. It was that concern which produced the Common Agricultural Policy. Now, in a more prosperous, high tech age, consumers are able to concentrate on how food is produced, what they want to buy, and the level of safety appropriate. It is in this context that the European Community's food policy, and the action necessary if the Community (that is the 12 Member States, with their 350 million consumers) is to establish a food policy which will suit the twenty‐first century, is considered.
Towards the introduction of health practices in catering
Authors: SIMPSON ANNE
Published: October 2007

Caterers have the necessary craft skills to implement Healthy Catering Practice providing: (i) it is taught consistently, (ii) they have access to dietitians who understand their problems, and (iii) that the various government bodies liaise to ensure that they receive the necessary clear guidelines and help.
Public notions on nutrition and the role of food scientists
Authors: GRENBY T. H.
Published: October 2007

The Food Chemistry Group of the Industrial Division of the Royal Society of Chemistry was invited to organise a session at the Annual Meeting of the British Association for the Advancement of Science, Plymouth, 26–30 August 1991, with the key object of explaining the importance of chemistry and other scientific disciplines in assuring the safety and quality of our food supply. This article is based on one of the presentations, outlining the need for scientific input to the food industry, the public's sources of information on food, some of the major advances that have been made by food chemists in recent years, and the industry's need for scientists and technologists.
Rapid methods of detection and enumeration of food poisoning micro‐organisms
Authors: WAITES WILL , DODD CHRIS , STEWART GORDON
Published: October 2007

Traditional methods of microbial detection and enumeration of food poisoning micro‐organisms can take up to seven days. In this time a product with a short shelf‐life can be distributed, sold and eaten. There is, therefore, an urgent need for more rapid methods, preferably those producing results at least within an eight hour working day. This article discusses the rapid methods of detection and enumeration which are currently under development. In particular, antibody‐linked probes, DNA hybridization, the polymerase chain reaction and the lux gene system will be examined, with a view to indicating where major advances could occur.
Adaptable and sustainable? Male farm service and the agricultural labour force in midland and southern England, c.1850–19251
Authors: HOWKINS ALUN , VERDON NICOLA
Published: October 2007

This article argues that farm service was an adaptable and sustainable system of hiring labour in areas of midland and southern England after 1850, having much in common with the model recently identified for northern England and Scotland. Analysing the Census Enumerators Books from selected parishes in seven counties in 1851, 1871, and 1891, we reveal an intricate pattern of farm service ‘survival’ both within and between counties. We then use a range of reports printed between the 1860s and 1920s to examine the national picture. The later regional persistence of farm service has implications for broader debates on the rural workforce and social relations.
Toward a Feminist State: What Does ‘Effective’ Prosecution of Domestic Violence Mean?
Authors: Dempsey Michelle Madden
Published: October 2007

This article examines domestic violence criminal prosecutions and addresses what ‘effective’ prosecutorial action means in such cases. The argument elaborates on a point recently articulated by the UN Special Rapporteur on Violence against Women, which links effective prosecution of violence against women to the creation of a less patriarchal society. The article concludes that ‘effective’ prosecution of domestic violence means prosecution which constitutes the State as less patriarchal ceteris paribus.
A longitudinal study over 5 to 10 years of clinical outcomes in women with idiopathic detrusor overactivity
Authors: Morris AR , Westbrook JI , Moore KH
Published: October 2007

Objective  To evaluate the long‐term clinical outcome in women with idiopathic detrusor overactivity (IDO) and to identify significant prognostic factors.

Design  Longitudinal study incorporating retrospective case note review and a postal questionnaire.

Setting  Tertiary referral urogynaecology clinic in Australia.

Population  Women with a sole urodynamic diagnosis of IDO.

Methods  Audit of urodynamic records and case notes. Postal questionnaire incorporating validated disease‐specific quality‐of‐life (QoL) instruments.

Main outcome measure  Subjective assessment of overall improvement on a 4‐point scale followed by scoring of short forms of the urogenital distress inventory and incontinence impact questionnaire.

Results  One hundred and thirty two women were identified following examination of 1975 consecutive records with 76 (67%) returning questionnaires. Median follow up was 8 years (6–9), and the duration of symptoms was 13 years (9–18). Improvement was achieved in 25 (35%) women. Disease symptoms fluctuated in severity and QoL were worse in nonresponders to therapy (P < 0.0001). Urge incontinence at presentation was associated with treatment failure (P= 0.001) as was nocturia (P= 0.04), but urodynamic variables were not associated with outcome. Only 3 of 46 (6.5%) women not responding to therapy thought that their symptoms would improve with time.

Conclusions  IDO seldom resolves and fluctuates in severity. Individual response is unpredictable, although the presence of urge incontinence is associated with a significantly worse prognosis.
Review article: Epigenetic control of fetal gene expression
Authors: Nafee TM , Farrell WE , Carroll WD , Fryer AA , Ismail KMK
Published: October 2007

Each differentiated cell type has its own epigenetic signature, which reflects its genotype, developmental history, and environmental influences, and is ultimately reflected in the phenotype of the cell and organism. Some cells undergo major epigenetic ‘reprogramming’ during fetal development. The proper, or improper, handling of these highly sensitive periods may have significant short‐term and long‐term effects on the newborn and his/her progeny. This review highlights the impact of environmental and nutritional factors on the epigenome and the potential effect of epigenetic dysregulation on maternal and fetal pregnancy outcomes, as well as possible long‐term implications.
Assessment of glomerular filtration rate during pregnancy using the MDRD formula
Authors: Smith MC , Moran P , Ward MK , Davison JM
Published: October 2007

It is now recommended practice to use estimated glomerular filtration rate (eGFR) values to screen for and monitor chronic renal disease. The most frequently used formula in the general population is that described following the Modification of Diet in Renal Disease (MDRD) study whereby serum creatinine is adjusted for age, gender and race. This study evaluates the performance of the MDRD formula in pregnancy by comparing eGFR with measured values obtained by inulin clearance studies in early and late normal pregnancy and in pregnancies complicated by renal disease or pre‐eclampsia. Our results indicate that in all situations, MDRD substantially underestimates glomerular filtration rate during pregnancy and cannot be recommended for use in clinical practice.
One‐year infant outcome in women with early‐onset hypertensive disorders of pregnancy
Authors: Rep A , Ganzevoort W , Van Wassenaer AG , Bonsel GJ , Wolf H , De Vries JIP ,   PETRA investigators
Published: October 2007

Objectives  To evaluate the role of plasma volume expansion on 1‐year infant outcome after severe hypertensive disorders of pregnancy and to determine prognostic factors for adverse neurodevelopmental infant outcome.

Design  Randomised controlled trial, observational prognostic study.

Setting  Two university hospitals in Amsterdam, The Netherlands.

Population  One hundred and seventy‐two infants alive of 216 mothers with severe hypertensive disorders of pregnancy who were randomised for a temporising management strategy with or without plasma volume expansion.

Methods  At 1 year of corrected age, a neurological examination according to Bayley (mental development index [MDI] and psychomotor development index [PDI]) and Touwen was performed.

Main outcome measures  Adverse neurodevelopmental infant outcome was defined as a MDI/PDI score below 70 and/or an abnormal Touwen. Risk factors for adverse neurodevelopmental outcome were explored by univariate and multivariate analyses.

Results  Adverse neurodevelopmental infant outcome was observed in 31 infants (18%). There were no differences between the randomisation groups. In multivariate analysis, an association with abnormal umbilical artery/middle cerebral artery Doppler ratio higher than the median, major neonatal morbidity, higher education of the parents, multiparity and Caucasian ethnicity was observed.

Conclusion  Nearly 70% of the infants were alive at 1 year without adverse neurodevelopmental outcome. Maternal plasma volume expansion during pregnancy has no effect on 1‐year infant outcome. The prediction of adverse outcome at 1 year by perinatal parameters is limited.
Characterization of nine microsatellite loci in the sea star Astropecten aranciacus and cross‐species amplification for related taxa
Authors: ZULLIGER D. , RUCH M. , TANNER S. , RIBI G.
Published: October 2007

So far, only few microsatellite markers have been developed and extensively tested for echinoderms. To study the population genetic structure of the sea star Astropecten aranciacus, we developed primers for nine polymorphic microsatellite loci and tested them on two populations from Faro in Portugal (N = 25) and from La Herradura in Spain (N = 20). Within populations, allele numbers varied from four to 20, while expected and observed heterozygosities ranged from 0.593 to 0.936 and from 0.222 to 0.900, respectively. Additional cross‐species amplifications were polymorphic at some loci, indicating their potential usefulness for related taxa.
A PCR assay for gender assignment in dugong (Dugong dugon) and West Indian manatee (Trichechus manatus)
Authors: MCHALE M. , BRODERICK D. , OVENDEN J. R. , LANYON J. M.
Published: October 2007

Gender assignment for some aquatic mammals in the field is difficult. Molecular sexing from tissue biopsies is possible as males are heterogametic. Here we describe a multiplex PCR assay that amplifies the male specific SRY gene and differentiates ZFX and ZFY gametologues in two sirenian species, dugong (Dugong dugon) and West Indian manatee (Trichechus manatus). The assay was validated with animals of known gender and proved accurate and robust to experimental failure.
Protective effect of melatonin on Ca2+ homeostasis and contractility in acute cholecystitis
Authors: Gomez‐Pinilla Pedro J. , Camello Pedro J. , Pozo María J.
Published: October 2007

Abstract:  Impaired Ca2+ homeostasis and smooth muscle contractility co‐exist in acute cholecystitis (AC) leading to gallbladder dysfunction. There is no pharmacological treatment for this pathological condition. Our aim was to evaluate the effects of melatonin treatment on Ca2+ signaling pathways and contractility altered by cholecystitis. [Ca2+]i was determined by epifluorescence microscopy in fura‐2 loaded isolated gallbladder smooth muscle cells, and isometric tension was recorded from gallbladder muscle strips. Malondialdehyde (MDA) and reduced glutathione (GSH) contents were determined by spectrophotometry and cycloxygenase‐2 (COX‐2) expression was quantified by western blot. Melatonin was tested in two experimental groups, one of which underwent common bile duct ligation for 2 days and another that was later de‐ligated for 2 days. Inflammation‐induced impairment of Ca2+ responses to cholecystokinin and caffeine were recovered by melatonin treatment (30 mg/kg). This treatment also ameliorated the detrimental effects of AC on Ca2+ influx through both L‐type and capacitative Ca2+ channels, and it was effective in preserving the pharmacological phenotype of these channels. Despite its effects on Ca2+ homeostasis, melatonin did not improve contractility. After de‐ligation, Ca2+ influx and contractility were still impaired, but both were recovered by melatonin. These effects of melatonin were associated to a reduction of MDA levels, an increase in GSH content and a decrease in COX‐2 expression. These findings indicate that melatonin restores Ca2+ homeostasis during AC and resolves inflammation. In addition, this indoleamine helps in the subsequent recovery of functionality.
Role of nitric oxide and prostacyclin as vasoactive hormones released by the endothelium
Authors: Mitchell Jane A. , Ali Ferhana , Bailey Lucy , Moreno Laura , Harrington Louise S.
Published: October 2007

The endothelium lines the luminal surface of every blood vessel, allowing it contact with circulating blood elements, as well as the underlying vascular smooth muscle layer. In healthy vessels, the endothelium expresses constitutive forms of nitric oxide synthase (NOSIII) and cyclo‐oxygenase (COX‐1), which produce the vasoactive hormones NO and prostacyclin, respectively. Both NO and prostacyclin relax blood vessels and inhibit platelet activation. The actions of prostacyclin are mediated by cell surface prostacyclin (IP) receptors and/or intracellular peroxisome proliferator‐activated receptors (PPAR)β. The actions of NO are mediated predominately by activation of intracellular guanylyl cyclase, leading to the formation of cGMP. In platelets, the actions of NO and prostacyclin are synergistic, but in vessels their actions are additive. In diseased vessels, inducible forms of NOS (NOSII) and cyclo‐oxygeanse (COX‐2) are expressed in vascular smooth muscle, resulting in the release of large amounts of NO, prostacyclin and prostaglandin E2. The relative contribution of NOSII and COX‐2 to vascular inflammation is still debated, but is likely to result in both protective and damaging responses. The relative contribution of constitutive forms of NOS and COX, as well as interactions between IP, PPARβ and guanylyl cyclase pathways in vessels and platelets, is discussed.
Thermal Optimization of an Internally Finned Tube Using Analytical Solutions Based on a Porous Medium Approach
Authors: Do Kyu Hyung , Min Jung Yim , Kim Sung Jin
Published: October 2007

The present work deals with thermal optimization of an internally finned tube having axial straight fins with axially uniform heat flux and peripherally uniform temperature at the wall. The physical domain was divided into two regions: One is the central cylindrical region of the fluid extending to the tips of the fins and the other constituted the remainder of the tube area. The latter region including the fins was modeled as a fluid-saturated porous medium. The Brinkman-extended Darcy equation for fluid flow and two-equation model for heat transfer were used in the porous region, while the classical Navier–Stokes and energy equations were used in the central cylindrical region. The analytical solutions for the velocity and temperature profiles were in close agreement with the corresponding numerical solution as well as with existing theoretical and experimental data. Finally, optimum conditions, where the thermal performance of the internally finned tube is maximized, were determined using the developed analytical solutions.
An Experimental Study of Shell-and-Tube Heat Exchangers With Continuous Helical Baffles
Authors: Peng B. , Wang Q. W. , Zhang C. , Xie G. N. , Luo L. Q. , Chen Q. Y. , Zeng M.
Published: October 2007

Two shell-and-tube heat exchangers (STHXs) using continuous helical baffles instead of segmental baffles used in conventional STHXs were proposed, designed, and tested in this study. The two proposed STHXs have the same tube bundle but different shell configurations. The flow pattern in the shell side of the heat exchanger with continuous helical baffles was forced to be rotational and helical due to the geometry of the continuous helical baffles, which results in a significant increase in heat transfer coefficient per unit pressure drop in the heat exchanger. Properly designed continuous helical baffles can reduce fouling in the shell side and prevent the flow-induced vibration as well. The performance of the proposed STHXs was studied experimentally in this work. The heat transfer coefficient and pressure drop in the new STHXs were compared with those in the STHX with segmental baffles. The results indicate that the use of continuous helical baffles results in nearly 10% increase in heat transfer coefficient compared with that of conventional segmental baffles for the same shell-side pressure drop. Based on the experimental data, the nondimensional correlations for heat transfer coefficient and pressure drop were developed for the proposed continuous helical baffle heat exchangers with different shell configurations, which might be useful for industrial applications and further study of continuous helical baffle heat exchangers. This paper also presents a simple and feasible method to fabricate continuous helical baffles used for STHXs.
Numerical Evaluation of Fin Performance Under Dehumidifying Conditions
Authors: Comini G. , Nonino C. , Savino S.
Published: October 2007

A numerical model of moist air cooling in compact heat exchangers is presented. The model requires the solution of a coupled problem, since interface temperatures, obtained from the solution of the energy equation in adjacent fluid and solid regions, are used to set the appropriate boundary conditions for the transport equation of water vapor in moist air. The approach is completely general, even if the finite-element method is used for the simulations reported in the paper. The numerical results are favorably compared with the corresponding experimental results concerning the rectangular and wavy fins under dehumidifying conditions.
The Parametric Study of an Innovative Offset Strip-Fin Heat Exchanger
Authors: De Losier Clayton Ray , Subramanian Sundaresan , Ponyavin Valery , Chen Yitung , Hechanova Anthony E. , Peterson Per F.
Published: October 2007

Offset strip-fin heat exchangers have numerous applications throughout various industries because they can provide a large amount of heat transfer area in a small volume. The widespread use of the offset strip-fin design has ensured that there are numerous dimensional variations and shown that changes in dimensional parameters affect performance. It is then important to understand how the geometry of an offset strip-fin heat exchanger can affect its performance. Therefore, an investigation into the parametric effects on the global performance of an innovative high-temperature offset strip-fin heat exchanger was numerically performed in this study, where the numerical solution was obtained through a finite-volume method. Computations were carried out for each of the heat exchanger’s geometrical parameters: fin thickness (t), fin length (l), channel height (H), spanwise pitch (px), and the newly introduced gap parameter (g). Also, the effects of rounding the fins leading and trailing edges were investigated, while the heat exchanger’s volume, mass flow rates, and inlet temperatures were kept constant. The results are presented in the form of pressure drops and heat transfer rates, and the coefficient of performance parameter shows that fins with rounded leading and trailing edges outperform fins with rectangular edges.
The Modeling of Viscous Dissipation in a Saturated Porous Medium
Authors: Nield D. A.
Published: October 2007

A critical review is made of recent studies of the modeling of viscous dissipation in a saturated porous medium, with applications to either forced convection or natural convection. Alternative forms of the viscous dissipation function are discussed. Limitations to the concept of fully developed convection are noted. Special attention is focused on the roles of viscous dissipation and work done by pressure forces (flow work) in natural convection in a two-dimensional box with either lateral or bottom heating.
Autoscreening of Restriction Endonucleases for PCR-Restriction Fragment Length Polymorphism Identification of Fungal Species, with
Pleurotus
spp. as an Example
Authors: Yang Zhi-Hui , Huang Ji-Xiang , Yao Yi-Jian
Published: October 2007

A molecular method based on PCR-restriction fragment length polymorphism (RFLP) analysis of internal transcribed spacer (ITS) ribosomal DNA sequences was designed to rapidly identify fungal species, with members of the genus
Pleurotus
as an example. Based on the results of phylogenetic analysis of ITS sequences from
Pleurotus
, a PCR-RFLP endonuclease autoscreening (PRE Auto) program was developed to screen restriction endonucleases for discriminating multiple sequences from different species. The PRE Auto program analyzes the endonuclease recognition sites and calculates the sizes of the fragments in the sequences that are imported into the program in groups according to species recognition. Every restriction endonuclease is scored through the calculation of the average coefficient for the sequence groups and the average coefficient for the sequences within a group, and then virtual electrophoresis maps for the selected restriction enzymes, based on the results of the scoring system, are displayed for the rapid determination of the candidate endonucleases. A total of 85 haplotypes representing 151 ITS sequences were used for the analysis, and 2,992 restriction endonucleases were screened to find the candidates for the identification of species. This method was verified by an experiment with 28 samples representing 12 species of
Pleurotus
. The results of the digestion by the restriction enzymes showed the same patterns of DNA fragments anticipated by the PRE Auto program, apart from those for four misidentified samples. ITS sequences from 14 samples (of which nine sequences were obtained in this study), including four originally misidentified samples, confirmed the species identities revealed by the PCR-RFLP analysis. The method developed here can be used for the identification of species of other living microorganisms.
Low Densities of Epiphytic Bacteria from the Marine Alga
Ulva australis
Inhibit Settlement of Fouling Organisms
Authors: Rao Dhana , Webb Jeremy S. , Holmström Carola , Case Rebecca , Low Adrian , Steinberg Peter , Kjelleberg Staffan
Published: October 2007

Bacteria that produce inhibitory compounds on the surface of marine algae are thought to contribute to the defense of the host plant against colonization of fouling organisms. However, the number of bacterial cells necessary to defend against fouling on the plant surface is not known.
Pseudoalteromonas tunicata
and
Phaeobacter
sp. strain 2.10 (formerly
Roseobacter gallaeciensis
) are marine bacteria often found in association with the alga
Ulva australis
and produce a range of extracellular inhibitory compounds against common fouling organisms.
P. tunicata
and
Phaeobacter
sp. strain 2.10 biofilms with cell densities ranging from 10
2
to 10
8
cells cm
−2
were established on polystyrene petri dishes. Attachment and settlement assays were performed with marine fungi (uncharacterized isolates from
U. australis
), marine bacteria (
Pseudoalteromonas gracilis
,
Alteromonas
sp., and
Cellulophaga fucicola
), invertebrate larvae (
Bugula neritina
), and algal spores (
Polysiphonia
sp.) and gametes (
U. australis
). Remarkably low cell densities (10
2
to 10
3
cells cm
−2
) of
P. tunicata
were effective in preventing settlement of algal spores and marine fungi in petri dishes.
P. tunicata
also prevented settlement of invertebrate larvae at densities of 10
4
to 10
5
cells cm
−2
. Similarly, low cell densities (10
3
to 10
4
cells cm
−2
) of
Phaeobacter
sp. strain 2.10 had antilarval and antibacterial activity. Previously, it has been shown that abundance of
P. tunicata
on marine eukaryotic hosts is low (<1 × 10
3
cells cm
−2
) (T. L. Skovhus et al., Appl. Environ. Microbiol. 70:2373-2382, 2004). Despite such low numbers of
P. tunicata
on
U. australis
in situ, our data suggest that
P. tunicata
and
Phaeobacter
sp. strain 2.10 are present in sufficient quantities on the plant to inhibit fouling organisms. This strongly supports the hypothesis that
P. tunicata
and
Phaeobacter
sp. strain 2.10 can play a role in defense against fouling on
U. australis
at cell densities that commonly occur in situ.
Molecular Dissection of a Bifidobacterial Replicon
Authors: Cronin Michelle , Knobel Moritz , O'Connell-Motherway Mary , Fitzgerald Gerald F. , van Sinderen Douwe
Published: October 2007

The 2.1-kb cryptic plasmid pCIBAO89 from
Bifidobacterium asteroides
harbors a 1.4-kb segment which is sufficient for its autonomous replication. The segment is divided into two parts, the presumed replication origin,
ori89
, and the
rep
gene encoding the putative 41-kDa Rep89 replication initiation protein. This minimal replication region of pCIBAO89 was functionally dissected by transcriptional analyses as well as by DNA-binding studies, and the information obtained was exploited to create a number of
Escherichia coli
-
Bifidobacterium
shuttle vectors capable of transforming various bifidobacteria with an efficiency of up to 10
6
transformants/μg DNA.
Effects of Dried Distillers’ Grain on Fecal Prevalence and Growth of
Escherichia coli
O157 in Batch Culture Fermentations from Cattle
Authors: Jacob M. E. , Fox J. T. , Drouillard J. S. , Renter D. G. , Nagaraja T. G.
Published: October 2007

Distillers’ grains (DG), a by-product of ethanol production, are fed to cattle. Associations between
Escherichia coli
O157 prevalence and feeding of DG were investigated in feedlot cattle (
n
= 379) given one of three diets: steam-flaked corn (SFC) and 15% corn silage with 0 or 25% dried distillers’ grains (DDG) or SFC with 5% corn silage and 25% DDG. Ten fecal samples were collected from each pen weekly for 12 weeks to isolate
E. coli
O157. Cattle fed 25% DDG with 5 or 15% silage had a higher (
P
= 0.01) prevalence of
E. coli
O157 than cattle fed a diet without DDG. Batch culture ruminal or fecal microbial fermentations were conducted to evaluate the effect of DDG on
E. coli
O157 growth. The first study utilized microbial inocula from steers fed SFC or dry-rolled corn with 0 or 25% DDG and included their diet as the substrate. Ruminal microbial fermentations from steers fed DDG had higher
E. coli
O157 contents than ruminal microbial fermentations from steers fed no DDG (
P
< 0.05) when no substrate was included. Fecal fermentations showed no DDG effect on
E. coli
O157 growth. In the second study with DDG as a substrate, ruminal fermentations with 0.5 g DDG had higher (
P
< 0.01)
E. coli
O157 concentrations at 24 h than ruminal fermentations with 0, 1, or 2 g DDG. In fecal fermentations, 2 g DDG resulted in a higher concentration (
P
< 0.05) at 24 h than 0, 0.5, or 1 g DDG. The results indicate that there is a positive association between DDG and
E. coli
O157 in cattle, and the findings should have important ramifications for food safety.
Effects of Granule-Associated Protein PhaP on Glycerol-Dependent Growth and Polymer Production in Poly(3-Hydroxybutyrate)-Producing
Escherichia coli
Authors: de Almeida Alejandra , Nikel Pablo I. , Giordano Andrea M. , Pettinari M. Julia
Published: October 2007

Polyhydroxyalkanoates (PHAs) are accumulated as intracellular granules by many bacteria under unfavorable conditions, enhancing their fitness and stress resistance. Poly(3-hydroxybutyrate) (PHB) is the most widespread and best-known PHA. Apart from the genes that catalyze polymer biosynthesis, natural PHA producers have several genes for proteins involved in granule formation and/or with regulatory functions, such as phasins, that have been shown to affect polymer synthesis. This study evaluates the effect of PhaP, a phasin, on bacterial growth and PHB accumulation from glycerol in bioreactor cultures of recombinant
Escherichia coli
carrying
phaBAC
from
Azotobacter
sp. strain FA8. Cells expressing
phaP
grew more, and accumulated more PHB, both using glucose and using glycerol as carbon sources. When cultures were grown in a bioreactor using glycerol, PhaP-bearing cells produced more polymer (2.6 times) and more biomass (1.9 times) than did those without the phasin. The effect of this protein on growth promotion and polymer accumulation is expected to be even greater in high-density cultures, such as those used in the industrial production of the polymer. The recombinant strain presented in this work has been successfully used for the production of PHB from glycerol in bioreactor studies, allowing the production of 7.9 g/liter of the polymer in a semisynthetic medium in 48-h batch cultures. The development of bacterial strains that can efficiently use this substrate can help to make the industrial production of PHAs economically feasible.
Density Gradient Enrichment of
Escherichia coli
Conditional
msbA
Mutants
Authors: Doerrler William T.
Published: October 2007

Insight into the mechanism of lipid transport to the outer membrane of gram-negative bacteria has been hampered by the lack of an effective genetic screen for defective mutants. This work demonstrates an enrichment of conditional mutants defective in lipopolysaccharide export by Ludox density gradient centrifugation and selection for detergent resistance. New temperature-sensitive mutants with lipid export defects were isolated with single missense mutations in
msbA
. The results demonstrate the power of this approach for the study of lipid export in
Escherichia coli
.
Role of DNA Mismatch Repair and Double-Strand Break Repair in Genome Stability and Antifungal Drug Resistance in
Candida albicans
Authors: Legrand Melanie , Chan Christine L. , Jauert Peter A. , Kirkpatrick David T.
Published: October 2007

Drug resistance has become a major problem in the treatment of
Candida albicans
infections. Genome changes, such as aneuploidy, translocations, loss of heterozygosity, or point mutations, are often observed in clinical isolates that have become resistant to antifungal drugs. To determine whether these types of alterations result when DNA repair pathways are eliminated, we constructed yeast strains bearing deletions in six genes involved in mismatch repair (
MSH2
and
PMS1
) or double-strand break repair (
MRE11, RAD50, RAD52
, and
YKU80
). We show that the
mre11
Δ/
mre11
Δ,
rad50
Δ/
rad50
Δ, and
rad52
Δ/
rad52
Δ mutants are slow growing and exhibit a wrinkly colony phenotype and that cultures of these mutants contain abundant elongated pseudohypha-like cells. These same mutants are susceptible to hydrogen peroxide, tetrabutyl hydrogen peroxide, UV radiation, camptothecin, ethylmethane sulfonate, and methylmethane sulfonate. The
msh2
Δ/
msh2
Δ,
pms1
Δ/
pms1
Δ, and
yku80
Δ/
yku80
Δ mutants exhibit none of these phenotypes. We observed an increase in genome instability in
mre11
Δ/
mre11
Δ and
rad50
Δ/
rad50
Δ mutants by using a
GAL1
/
URA3
marker system to monitor the integrity of chromosome 1. We investigated the acquisition of drug resistance in the DNA repair mutants and found that deletion of
mre11
Δ/
mre11
Δ,
rad50
Δ/
rad50
Δ, or
rad52
Δ/
rad52
Δ leads to an increased susceptibility to fluconazole. Interestingly, we also observed an elevated frequency of appearance of drug-resistant colonies for both
msh2
Δ/
msh2
Δ and
pms1
Δ/
pms1
Δ (MMR mutants) and
rad50
Δ/
rad50
Δ (DSBR mutant). Our data demonstrate that defects in double-strand break repair lead to an increase in genome instability, while drug resistance arises more rapidly in
C. albicans
strains lacking mismatch repair proteins or proteins central to double-strand break repair.
Kinetics of Polynucleotide Phosphorylase: Comparison of Enzymes from
Streptomyces
and
Escherichia coli
and Effects of Nucleoside Diphosphates
Authors: Chang Samantha A. , Cozad Madeline , Mackie George A. , Jones George H.
Published: October 2007

We examined the activity of polynucleotide phosphorylase (PNPase) from
Streptomyces coelicolor
,
Streptomyces antibioticus
, and
Escherichia coli
in phosphorolysis using substrates derived from the
rpsO-pnp
operon of
S. coelicolor
. The
Streptomyces
and
E. coli
enzymes were both able to digest a substrate with a 3′ single-stranded tail although
E. coli
PNPase was more effective in digesting this substrate than were the
Streptomyces
enzymes. The
k
cat
for the
E. coli
enzyme was ca. twofold higher than that observed with the
S. coelicolor
enzyme.
S. coelicolor
PNPase was more effective than its
E. coli
counterpart in digesting a substrate possessing a 3′ stem-loop structure, and the

K
m

for the
E. coli
enzyme was ca. twice that of the
S. coelicolor
enzyme. Electrophoretic mobility shift assays revealed an increased affinity of
S. coelicolor
PNPase for the substrate possessing a 3′ stem-loop structure compared with the
E. coli
enzyme. We observed an effect of nucleoside diphosphates on the activity of the
S. coelicolor
PNPase but not the
E. coli
enzyme. In the presence of a mixture of 20 μM ADP, CDP, GDP, and UDP, the

K
m

for the phosphorolysis of the substrate with the 3′ stem-loop was some fivefold lower than the value observed in the absence of nucleoside diphosphates. No effect of nucleoside diphosphates on the phosphorolytic activity of
E. coli
PNPase was observed. To our knowledge, this is the first demonstration of an effect of nucleoside diphosphates, the normal substrates for polymerization by PNPase, on the phosphorolytic activity of that enzyme.
The Metalloprotease ofListeria monocytogenesIs Activated by Intramolecular Autocatalysis
Authors: Bitar Alan Pavinski , Cao Min , Marquis Hélène
Published: October 2007

The metalloprotease (Mpl) ofListeria monocytogenesis a thermolysin-like protease that mediates the maturation of a broad-range phospholipase C, whose function contributes to the ability of this food-borne bacterial pathogen to survive intracellularly. Mpl is made as a proprotein that undergoes maturation by proteolytic cleavage of a large N-terminal prodomain. In this study, we identified the N terminus of mature Mpl and generated Mpl catalytic mutants to investigate the mechanism of Mpl maturation. We observed that Mpl activity was a prerequisite for maturation, suggesting a mechanism of autocatalysis. Furthermore, using a strain ofL. monocytogenesexpressing both the wild-type form and a catalytic mutant form of Mpl simultaneously, we determined that in vivo maturation of Mpl occurs exclusively by an intramolecular autocatalysis mechanism.
Effects of Single-Strand DNases ExoI, RecJ, ExoVII, and SbcCD on Homologous Recombination of
recBCD
+
Strains of
Escherichia coli
and Roles of SbcB15 and XonA2 ExoI Mutant Enzymes
Authors: Thoms Brigitte , Borchers Inka , Wackernagel Wilfried
Published: October 2007

To assess the contributions of single-strand DNases (ssDNases) to recombination in a
recBCD
+
background, we studied 31 strains with all combinations of null alleles of exonuclease I (Δ
xon
), exonuclease VII (
xseA
), RecJ DNase (
recJ
), and SbcCD DNase (
sbcCD
) and exonuclease I mutant alleles
xonA2
and
sbcB15
. The
xse recJ sbcCD
Δ
xon
and
xse recJ sbcCD sbcB15
quadruple mutants were cold sensitive, while the quadruple mutant with
xonA2
was not. UV sensitivity increased with ssDNase deficiencies. Most triple and quadruple mutants were highly sensitive. The absence of ssDNases hardly affected P1 transductional recombinant formation, and conjugational recombinant production was decreased (as much as 94%) in several cases. Strains with
sbcB15
were generally like the wild type. We determined that the
sbcB15
mutation caused an A183V exchange in exonuclease motif III and identified
xonA2
as a stop codon eliminating the terminal 8 amino acids. Purified enzymes had 1.6% (SbcB15) and 0.9% (XonA2) of the specific activity of wild-type Xon (Xon
+
), respectively, with altered activity profiles. In gel shift assays, SbcB15 associated relatively stably with 3′ DNA overhangs, giving protection against Xon
+
. In addition to their postsynaptic roles in the RecBCD pathway, exonuclease I and RecJ are proposed to have presynaptic roles of DNA end blunting. Blunting may be specifically required during conjugation to make DNAs with overhangs RecBCD targets for initiation of recombination. Evidence is provided that SbcB15 protein, known to activate the RecF pathway in
recBC
strains, contributes independently of RecF to recombination in
recBCD
+
cells. DNA end binding by SbcB15 can also explain other specific phenotypes of strains with
sbcB15
.
Interactions of the Energy Transducer TonB with Noncognate Energy-Harvesting Complexes
Authors: Brinkman Kerry K. , Larsen Ray A.
Published: October 2007

The TonB and TolA proteins are energy transducers that couple the ion electrochemical potential of the cytoplasmic membrane to support energy-dependent processes at the outer membrane of the gram-negative envelope. The transfer of energy to these transducers is facilitated by energy-harvesting complexes, which are heteromultimers of cytoplasmic membrane proteins with homologies to proton pump proteins of the flagellar motor. Although the cognate energy-harvesting complex best services each transducer, components of the complexes (for TonB, ExbB and ExbD; for TolA, TolQ and TolR) are sufficiently similar that each complex can imperfectly replace the other. Previous investigations of this molecular cross talk considered energy-harvesting complex components expressed from multicopy plasmids in strains in which the corresponding genes were interrupted by insertions, partially absent due to polarity, or missing due to a larger deletion. These questions were reexamined here using strains in which individual genes were removed by precise deletions and, where possible, components were expressed from single-copy genes with native promoters. By more closely approximating natural stoichiometries between components, this study provided insight into the roles of energy-harvesting complexes in both the energization and the stabilization of TonB. Further, the data suggest a distinct role for ExbD in the TonB energy transduction cycle.