bluuebunny/crossref_metadata_2025 huggingface dataset:
Cluster of Cases of Severe Acute Respiratory Syndrome Among Toronto Healthcare Workers After Implementation of Infection Control Precautions: A Case Series
Authors: Ofner-Agostini Marianna , Gravel Denise , McDonald L. Clifford , Lem Marcus , Sarwal Shelley , McGeer Allison , Green Karen , Vearncombe Mary , Roth Virginia , Paton Shirley , Loeb Mark , Simor Andrew
Published: May 2006

Objective.

To review the severe acute respiratory syndrome (SARS) infection control practices, the types of exposure to patients with SARS, and the activities associated with treatment of such patients among healthcare workers (HCWs) who developed SARS in Toronto, Canada, after SARS-specific infection control precautions had been implemented.

Methods.

A retrospective review of work logs and patient assignments, detailed review of medical records of patients with SARS, and comprehensive telephone-based interviews of HCWs who met the case definition for SARS after implementation of infection control precautions.

Results.

Seventeen HCWs from 6 hospitals developed disease that met the case definition for SARS after implementation of infection control precautions. These HCWs had a mean age ( ± SD) of 39 ± 2.3 years. Two HCWs were not interviewed because of illness. Of the remaining 15, only 9 (60%) reported that they had received formal infection control training. Thirteen HCWs (87%) were unsure of proper order in which personal protective equipment should be donned and doffed. Six HCWs (40%) reused items (eg, stethoscopes, goggles, and cleaning equipment) elsewhere on the ward after initial use in a room in which a patient with SARS was staying. Use of masks, gowns, gloves, and eyewear was inconsistent among HCWs. Eight (54%) reported that they were aware of a breach in infection control precautions. HCWs reported fatigue due to an increase number and length of shifts; participants worked a median of 10 shifts during the 10 days before onset of symptoms. Seven HCWs were involved in the intubation of a patient with SARS. One HCW died, and the remaining 16 recovered.

Conclusion.

Multiple factors were likely responsible for SARS in these HCWs, including the performance of high-risk patient care procedures, inconsistent use of personal protective equipment, fatigue, and lack of adequate infection control training.
Perioperative Intranasal Mupirocin for the Prevention of Surgical-Site Infections: Systematic Review of the Literature and Meta-Analysis
Authors: Kallen Alexander J. , Wilson Chad T. , Larson Robin J.
Published: May 2006

Objective:

To review the evidence evaluating perioperative intranasal mupirocin for the prevention of surgical-site infections according to type of surgical procedure.

Design:

Systematic review and meta-analysis of published clinical trials.

Setting:

Studies included were either randomized clinical trial or prospective trials at a single institution that measured outcomes both before and after an institution-wide intervention (before-after trial). In all studies, intervention and control groups differed only by the use of perioperative intranasal mupirocin in the intervention group.

Patients:

Patients undergoing general or nongeneral surgery (eg, cardiothoracic surgery, orthopedic surgery, and neurosurgery).

Main Outcome Measure:

Risk of surgical-site infection following perioperative intranasal mupirocin versus usual care.

Results:

Three randomized and four before-after trials met the inclusion criteria. No reduction in surgical-site infection rate was seen in randomized general surgery trials (summary estimates: 8.4% in the mupirocin group and 8.1% in the control group; relative risk [RR], 1.04; 95% confidence interval [CI95], 0.81 to 1.33). In nongeneral surgery, the use of mupirocin was associated with a reduction in surgical-site infection in randomized trials (summary estimates: 6.0% in the mupirocin group and 7.6% in the control group; RR, 0.80; CI95, 0.58 to 1.10) and in before-after trials (summary estimates: 1.7% in the mupirocin group and 4.1% in the control group; RR, 0.40; CI95, 0.29 to 0.56).

Conclusions:

Perioperative intranasal mupirocin appears to decrease the incidence of surgical-site infection when used as prophylaxis in nongeneral surgery. Given its low risk and low cost, use of perioperative intranasal mupirocin should be considered in these settings.
Hair Removal Policies in Clean Surgery: Systematic Review of Randomized, Controlled Trials
Authors: Niël-Weise B. S. , Wille J. C. , van den Broek P. J.
Published: May 2006

Objective:

To determine whether certain hair removal policies are better than others to prevent surgical-site infections in patients undergoing clean surgery.

Methods:

Publications were retrieved by a systematic search of Medline, the Cochrane Library, and EMBASE up to February 2005. Additionally, the reference lists of all identified trials were examined. All randomized trials, quasi-randomized trials, and systematic reviews or meta-analyses of randomized or quasi-randomized trials comparing hair removal policies in clean surgery were selected. Trials involving patients undergoing cranial neurosurgery were excluded. Two reviewers independently assessed trial quality and extracted data. Disagreements were resolved by discussion with a third reviewer. Data from the original publications were used to calculate the relative risk or risk difference of surgical-site infection. Data for similar outcomes were combined in the analysis, where appropriate, with the use of a random effects model.

Results:

Four trials were included in the review. No eligible systematic review or meta-analysis of randomized or quasi-randomized trials was found. The quality of the trials and how they were reported were generally unsatisfactory. Evidence regarding whether preoperative hair removal has any effect was inconclusive. When hair removal was considered necessary, evidence about the best time for removal was inconclusive. There was some evidence that hair removal by clipper is superior to removal by razor.

Conclusions:

Because of insufficient evidence as a basis for recommendations, the practical consequences for ward management were essential when the Dutch Working Party on Infection Prevention formulated its recommendations for hair removal policies. Large randomized, controlled trials are needed to determine the optimal policy for preoperative hair removal.
Flâneurie on bicycles: acquiescence to women in public in the 1890s
Authors: Mackintosh Phillip Gordon , Norcliffe Glen
Published: May 2006

Although scholars have established the publicity of all types of nineteenth‐century women, their public actions are still regarded as morally constrained. We offer one group of public women, bourgeois cyclists, who after encountering public skepticism only briefly were given free rein of the streets and country roads. This propensity of women and men to ride the thoroughfares ‘a‐wheel’ we refer to as flâneurie on bicycles, a technology‐mediated form of the pedestrian variety. Similarities and differences necessarily abound because of the requirements of safe cycling and the long‐distance rambling capacity of cyclists. We argue, however, that flâneurie of the bicycle kind is largely faithful to the original in that cycling promoted peripatetic individualism, for female as well as male riders.
‘The last frontier’: rationalizing the spread of farming into the boreal woods of Canada, c. 1910–1940
Authors: Wood J. David
Published: May 2006

As the twentieth century opened, there were rumours that the cheap land underpinning the dramatic spread of settlement in the previous century might be running out. There were strong motivations, generated particularly by the large body of land seekers with a passion for farming, to hold off the demise of the famous agricultural frontier. Also wedded to the continuation of a frontier were politicians and civil servants across the country. Whether it was a subconscious expectation that the frontier would simply continue or a fear that its disappearance would lead to unpredictable social disturbance, politicians encouraged expansion beyond what was known to be good farmland. The major source of new land, from c. 1910, was the boreal forest. There was a steady accumulation of information about the North that was readily available to government officials but only indirectly to ordinary land seekers. Although the news about farming conditions in the boreal margin was unpromising except for a few pockets, independent and assisted farm settlements continued into the 1930s. The typical two‐thirds of farm failure within one generation in most of the new boreal settlements caused a great deal of settler grief and forced reluctant officials to respond to the negative scientific evidence and to reassess frontier nostalgia. The Second World War provided both a denouement of the northern farm settlement and a reason for many people to depart the ‘last frontier’.
Primate embryonic stem cells create their own niche while differentiating in three‐dimensional culture systems
Authors: Michelini M. , Franceschini V. , Sihui Chen S. , Papini S. , Rosellini A. , Ciani F. , Margolis L. , Revoltella R. P.
Published: May 2006

Abstract.   Rhesus monkey embryonic stem cells (ESCs) (R366.4), cultured on a three‐dimensional (3D) collagen matrix with or without human neonatal foreskin fibroblasts (HPI.1) as feeder cells, or embedded in the collagen matrix, formed complex tubular or spherical gland‐like structures and differentiated into phenotypes characteristic of neural, epithelial and endothelial lineages. Here, we analysed the production of endogenous extracellular matrix (ECM) proteins, cell–cell adhesion molecules, cell‐surface receptors, lectins and their glycoligands, by differentiating ESCs, forming a micro‐environment, a niche, able to positively influence cell behaviour. The expression of some of these molecules was modulated by HPI.1 cells while others were unaffected. We hypothesized that both soluble factors and the niche itself were critical in directing growth and/or differentiation of ESCs in this 3D environment. Creating such an appropriate experimental 3D micro‐environment, further modified by ESCs and modulated by exogenous soluble factors, may constitute a template for adequate culture systems in developmental biology studies concerning differentiation of stem cells.
Effect of transfection with a gene coding for the fibronectin FNIII/10 fragment upon contact inhibition of C3H10T1/2 fibroblasts
Authors: Miłoszewska J. , Szaniawska B. , Trembacz H. , Gos M. , Przybyszewska M. , Swoboda P. , Małecki M. , Janik P.
Published: May 2006

Abstract.   The density‐dependent growth inhibition of non‐transformed cells may be associated with inefficient transduction of the proliferative signal from cell adhesion molecules. To verify this concept, the C3H10T1/2 fibroblasts were stably transfected with the gene coding for the fibronectin fragment III/10 (FNIII/10). This resulted in differences in gene's expression between original C3H10T1/2 cells and their FNIII/10 transfectants. No significant differences in growth properties were observed in the original or in the transfected cells. C3H10T1/2 cells and their transfectants, when co‐cultured, displayed more cells at confluence than the cells cultured alone. Moreover, co‐cultured C3H10T1/2 cells and their transfectants showed elevated levels of phospho‐ERK1/2 compared to homogenous cultures. Results obtained indicate that cellular homogeneity is responsible for density‐dependent growth inhibition.
An evaluation of 2D‐image analysis techniques for measuring soil microporosity
Authors: Marcelino V. , Cnudde V. , Vansteelandt S. , Carò F.
Published: May 2006

To compare soil porosity measurements, manual, semiautomatic and automatic 2D‐image analyses were performed on three sets of images of the same fields. The first and second image sets were obtained, by a fluorescence microscope, on the polished surfaces of soil blocks impregnated with a fluorescent resin and on the thin sections made from them, respectively. A scanning electron microscope in backscattered mode was used to acquire the third set of images on the thin sections. In the manual image analysis procedure, image segmentation was based on the best visual impression and carried out individually for each image with the UTHSCSA Image Tool software. For the semiautomatic method, the software μCTanalySIS was used; the images were segmented by double hysteresis, after interactive selection of the thresholding values. Automatic thresholding, based on an analysis of the image intensity histogram, was performed using the image analysis software Image‐Pro® Plus. Average microporosity measurements were compared between image types and image analysis methods using marginal regression models for continuous outcomes. The mean area covered by pores was significantly different depending on the type of image and the method of image analysis. Results after the automatic procedure were significantly larger than after manual or semiautomatic thresholding. On the other hand, average porosities were larger for backscattered electron images than for fluorescent images, regardless of the image analysis procedure used. These results stress the need for standardization of image analysis protocols and warn of the dangers of comparing soil porosity measurements performed on different types of images.
Experimental transmission of sleeping disease in one‐year‐old rainbow trout, Oncorhynchus mykiss (Walbaum), induced by sleeping disease virus
Authors: Boscher S Kerbart , McLoughlin M , Le Ven A , Cabon J , Baud M , Castric J
Published: May 2006

Sleeping disease (SD) is a serious disease of rainbow trout, Oncorhynchus mykiss, reared in fresh water caused by sleeping disease virus (SDV). In this study a detailed clinical, histological, virological and serological description of the experimental reproduction of SD in 1‐year‐old rainbow trout exposed to SDV was carried out. Two hundred disease‐free fish were intraperitoneally inoculated with a SDV isolate and 100 fish were inoculated with an uninfected cell culture lysate as a negative control. Infected and control fish were randomly removed at days 4, 7, 14, 21, 42 and 70 post‐infection. Blood and tissues were collected for virus isolation, histopathological examination and serum neutralization. SDV was detected in serum, kidney and brain of infected fish from 4 to 21 days post‐infection (dpi). Characteristic pathological lesions were observed in infected fish as early as 7 dpi. Lesions were first detected in exocrine pancreas and subsequently observed in heart and skeletal muscle. Neutralizing antibodies to SDV were detected in infected fish from 14 to 70 dpi. Infected fish displayed typical signs of SD 1‐month pi and the mortality reached 18.7% within 44 days. This study experimentally reproduced all the pathognomonic features of natural outbreaks of SD in 1‐year‐old rainbow trout.
Ocular and airway symptoms related to organic acid anhydride exposure – a prospective study
Authors: Nielsen J. , Welinder H. , Bensryd I. , Rylander L. , Skerfving S.
Published: May 2006

Background:  Organic acid anhydrides (OAA) are used as hardeners in epoxy resin systems. They are powerful sensitizers giving frequent rhinitis and asthma in exposed workers. Incidence of symptoms is unknown. Here we present the first prospective study on the associations between OAA exposure, symptoms, and effects of confounding factors.

Methods:  All new employees in three plants handling OAA were followed for up to 8.5 years. Before the employment, a questionnaire reporting about symptoms of eyes and airways, smoking habits, and atopy was answered. The subjects were asked at regular medical examinations about work tasks and work‐related symptoms. Serum was analysed for specific OAA antibodies.

Results:  Mean exposures varied between 6 and 39 μg/m3. The incidence for work‐related symptoms of the eyes, nose, pharynx, and lower airways was 91, 64, 46, and 31 per 1000 years of exposure, respectively. Symptoms were found frequently, even at mean exposure level at <10 μg/m3. Smoking and atopy increased the risk of symptoms. Immunoglobulin (Ig)E sensitized workers had a significant increased risk for symptoms of the eyes and pharynx and for running nose/sneezing.

Conclusions:  Organic acid anhydrides exposure is associated with frequent ocular and airway symptoms even at mean exposure levels at <10 μg/m3. There is an important need for establishment of an occupational threshold limit. A limit value of below 5 μg/m3 is proposed.
Immunological characteristics correlating with clinical response to immunotherapy in patients with advanced metastatic melanoma
Authors: Marshall Julia A , Forster Trevor H , Purdie David M , Lanagan Catherine M , O'Connor Linda E , O'rourke Michael GE , Johnson Maree K , See Janet L , Ellem Kay AO , Martinez Nathan R , López J Alejandro , Schmidt Christopher W
Published: May 2006

Current treatment options for advanced metastatic melanoma are limited to experimental regimen that provide poor survival outcomes. Immunotherapy is a promising alternative and we recently reported a clinical trial in which 6 out of 19 patients enrolled had objective clinical responses to a fully autologous melanoma/dendritic cell vaccine. The mechanism of the vaccine is not well understood, but we hypothesized that general immunocompetence may be a determinant of clinical response. We therefore examined the immune status of an expanded series of 21 patients who displayed varying clinical responses to the melanoma/dendritic cell vaccine. Immunocompetence was assessed using in vitro assays of lymphocyte function: survival, proliferation and cytokine responses to mitogen stimulation as well as T‐cell receptor ζ expression and lymphocyte subset analysis. Although lymphocytes from patients mostly performed comparably to age‐matched and sex‐matched controls, in some assays we identified significant differences between complete clinical responders and other patients, both before and following vaccination. Surprisingly, before vaccination, only lymphocytes from clinical responder patients showed impaired in vitro survival. Following vaccination, T lymphocyte survival improved and cells recovered their ability to produce the Th1‐associated cytokines TNF and IFN‐γ in response to anti‐CD3 stimulation in vitro. No increase in Th1 cytokine production was observed in lymphocytes from patients who experienced partial clinical responses or progressive disease. We conclude that, before vaccination, patients who go on to have complete responses have immune characteristics suggestive of high cell turnover and low Th1‐associated cytokine production, and that these can be reversed with vaccination. These results have potential implications for future immunotherapeutic strategies.
Narrative Identity Processing of Difficult Life Experiences: Pathways of Personality Development and Positive Self‐Transformation in Adulthood
Authors: Pals Jennifer L.
Published: May 2006

ABSTRACT
Difficult life experiences in adulthood constitute a challenge to the narrative construction of identity. Individual differences in how adults respond to this challenge were conceptualized in terms of two dimensions of narrative identity processing: exploratory narrative processing and coherent positive resolution. These dimensions, coded from narratives of difficult experiences reported by the women of the Mills Longitudinal Study (Helson, 1967) at age 52, were expected to be related to personality traits and to have implications for pathways of personality development and physical health. First, the exploratory narrative processing of difficult experiences mediated the relationship between the trait of coping openness in young adulthood (age 21) and the outcome of maturity in late midlife (age 61). Second, coherent positive resolution predicted increasing ego‐resiliency between young adulthood and midlife (age 52), and this pattern of increasing ego‐resiliency, in turn, mediated the relationship between coherent positive resolution and life satisfaction in late midlife. Finally, the integration of exploratory narrative processing and coherent positive resolution predicted positive self‐transformation within narratives of difficult experiences. In turn, positive self‐transformation uniquely predicted optimal development (composite of maturity and life satisfaction) and physical health.
Non‐audit Services and Auditor Independence: New Zealand Evidence
Authors: Hay David , Knechel Robert , Li Vivian
Published: May 2006

Abstract:  This paper examines evidence in New Zealand about whether auditors providing more non‐audit services are less independent. Three sets of tests are used to address the issue. The first examines whether there is a relation between non‐audit fees and audit fees, the second examines whether there is a relation between non‐audit fees and audit report qualification or modification, and the third examines whether there is a relation between non‐audit fees and stability of audit tenure. The results suggest a potential for the impairment of auditor independence in appearance when auditors provide non‐audit services but no evidence of any impact on independence of mind.
UPTAKE OF SULPHUR BY MYGORRHIZAL PLANTS
Authors: MORRISON T. M.
Published: May 2006

Summary

Two experiments were consistent in showing that mycorrhizas are of no significance in sulphur accumulation by Pinus radiata even after a period of sulphur starvation. It is concluded that unlike phosphorus, sulphur has a free pathway through the mycelium of the mycorrhizal fungus.
ECOTYPIG DIFFERENTIATION OF CALLUNA VULGARIS (L.) IN RELATION TO ALTITUDE
Authors: GRANT SHEILA A. , HUNTER R. F.
Published: May 2006

Summary

Population studies of Calluna vulgaris (L.) were undertaken in order to investigate plant variations genotypic in origin. Seed was collected from ten widely separated areas in Great Britain and seedlings from each population were grown in a spaced plant trial. In a later study plants were raised from seed collected at high and low altitudes from within sixteen centres in Scotland.

Data were collected on growth habit, flowering and frost resistance.

The results indicate that ecotypic differentiation occurs and that the pattern of differentiation is ecoclinal.

(i) Variation in growth habit is continuous and the proportions of the various growth forms change with change in altitude.

(ii) Maturity type is related to the length of the growing season at the site of origin of the population. Populations originating from areas having shorter growing seasons are composed of individuals of an earlier maturity type than those from areas where the season is longer.

(iii) Observations on frost damage were made in the first study. The numbers of susceptible plants were too low to permit population comparison but susceptibility could be related to soil and climatic variation.

The significance of the variational trends is discussed.
CYTOTAXONOMIC STUDIES IN HOLCUS
Authors: JONES KEITH , CARROLL CHRISTOPHER P.
Published: May 2006

Summary

A randomized block experiment was laid down to compare the morphology of the tetraploid, pentaploid and hexaploid races of Holcus mollis. No qualitative differences have been found to distinguish the races.

Quantitative differences exist, but are not sufficiently large to allow a taxonomic separation. The morphology of the pentaploid mollis is discussed in relation to its possible hybrid origin involving H. lanatus.
PLANT GROWTH RESPONSES TO VESICULAR‐ARBUSCULAR MYCORRHIZA V. PHOSPHATE UPTAKE BY THREE PLANT SPECIES FROM P‐DEFICIENT SOILS LABELLED WITH 32P
Authors: MOSSE B. , HAYMAN D. S. , ARNOLD D. J.
Published: May 2006

The uptake of phosphorus from 32P‐labelled soil solution by three plant species, with and without mycorrhiza, was measured. All soils contained very little CaCl2‐ and NaHCO3‐soluble phosphorus. In two soils the specific activity of phosphorus taken up by mycorrhizal and non‐mycorrhizal Melinis minutiflora was very similar, indicating that even in very P‐deficient soils mycorrhizal plants used the same source of phosphate as non‐mycorrhizal. In two other soils non‐mycorrhizal Paspalum notatum and Centrosema pebescens contained no 32P activity, suggesting that they had not taken up any soil phosphorus, whereas mycorrhizal plants of both species contained 32P activity and grew much better. It is suggested that non‐mycorrhizal roots of some plant species do not utilize phosphate present at extremely low concentrations in the soil solution, but that mycorrhizal roots or fungal hyphae do. The implications of this finding for the mechanism of phosphate uptake by VA mycorrhiza are discussed.
CYTOLOGICAL STUDIES IN THE GENUS SILENE L.
Authors: BARI E. ABDEL
Published: May 2006

Chromosome counts on twenty‐two taxa of Silene L. confirmed that the genus is dibasic with ×= 10 or 12. Most European species have 2n= 24, but species of Section Conomorpha have 2n= 20. No cytodemes were found in any annual taxa, but within the perennial S. vulgaris the Mediterranean subsp. macrocarpa is tetraploid with 2n= 48. Karyotype comparisons showed the frequent presence of a satellited chromosome, and a large variation in chromosome size between species.
HEAT SENSITIVITY OF ESTERASE ISOZYMES IN THE STYLES OF LILIUM AND NICOTIANA
Authors: PANDEY KAMLA KANT
Published: May 2006

The heat sensitivity of esterase isozymes in styles was studied by the method of acrylamide gel electrophoresis in nine clones of Lilium and fifteen species of Nicotiana. The material included both self‐incompatible and self‐compatible species, strains or clones, and the Nicotiana species comprised natives of South America, Australia and South Pacific islands.

The heat response was highly specific to particular isozymes, the affected isozyme bands usually disappearing completely under treatment while the other bands usually remained unaffected. The remarkable specificity of isozymes to heat is thought to be significant in adaptation of plants to different temperature conditions. This discovery offers the possibility of using the gel electrophoretic technique for identifying heat resistant and heat sensitive genetic eco‐types for breeding high‐yielding varieties specifically suited to different environmental conditions.

In Lilium, heat response occurred exclusively in self‐incompatible clones, all self‐compatible clones showing no response. Among the South American Nicotiana species most genotypes in all self‐incompatible species showed heat response and about two‐thirds of the material in self‐compatible species showed at least some response. However, all the examined Australian species and the one South Pacific islands species, which are all self‐compatible, showed no heat response.

The heat response in the species of Australia and South Pacific islands is discussed with reference to Waddington's concept of ‘canalization’ and ‘genetic assimilation’. The possible significance of two other general characteristics of isozyme bands in these species, namely, the comparatively lower total number and their generally slower movement in the gel, is considered briefly.
A NUMERICAL ANALYSIS OF THE PAST AND PRESENT FLORA OF THE BRITISH ISLES
Authors: BIRKS H. J. B. , DEACON JOY
Published: May 2006

Lists of all the taxa of vascular plants recorded from deposits of Late‐Devensian, mid‐Flandrian, and late‐Flandrian age in twelve geographical regions of Britain were compiled. From these lists coefficients of floristic dissimilarity between the regions were calculated, and two‐dimensional dispositions of points representing the regions were found for each time interval by non‐metric multidimensional scaling. Distributional data for the present day were analysed in a similar way. The method demonstrates a marked north‐south floristic gradient in the British Isles today, and analyses of the fossil data suggest that although a gradient was present in Late‐Devensian and mid‐Flandrian times it only became well developed in late‐Flandrian times. Phytogeographical analyses of the flora in each region at each time interval also demonstrate the existence of some west‐east floristic gradients, particularly in Late‐Devensian times. It is concluded that, despite the many limitations of the primary floristic data, the numerical methods have considerable potential for handling and synthesizing large amounts of historical biogeographical data.
UPTAKE OF GLUCOSE, TREHALOSE AND MANNITOL BY LEAF SLICES OF THE ORCHID BLETILLA HYACINTHINA
Authors: SMITH S. E. , SMITH F. A.
Published: May 2006

Glucose, trehalose and mannitol were all absorbed by leaf slices of the orchid Bletilla hyacinthina. The rates of uptake of trehalose and mannitol were respectively 17.8% and 33.6% of the glucose uptake rate. Absorption of all three carbohydrates was reduced by low temperature or the presence of the inhibitor CCCP.

Glucose and trehalose were extensively metabolized within the tissues and 14C appeared in both ionized and neutral compounds. Of the latter sucrose was the most heavily labelled. In contrast mannitol was scarcely metabolized at all.

These results are compared with recently reported experiments on the germination of B. hyacinthina on glucose, trehalose or mannitol.
SOIL AERATION, NITRATE REDUCTION AND FLOODING TOLERANCE IN HIGHER PLANTS
Authors: GARCIA‐NOVO F. , CRAWFORD R. M. M.
Published: May 2006

Flood‐tolerant species from natural habitats differ from flood‐intolerant species by being able to make more effective use of nitrate as an alternative electron acceptor to oxygen during periods of partial anaerobiosis. When flooded, tolerant species show marked increases in nitrate‐reductase activity in roots and leaves. A greater ability to synthesize amino‐acids under anoxia was also found in the tolerant species than in the intolerant. It is suggested that these properties enable the flood‐tolerant species to facilitate the re‐oxidation of NADH2 under conditions of anoxia and that this is associated with the greater ability of the species to withstand a reduction in the partial pressure of oxygen.
ZINC, LEAD AND COPPER TOLERANCE IN THE GRASS STEREOCHLAENA CAMERONII (STAPF) CLAYTON
Authors: REILLY ANN , REILLY C.
Published: May 2006

Stereochlaena cameronii, a grass widely distributed in south central Africa, possesses tolerance towards heavy metals. Its tolerance and accumulation of zinc, lead, copper, iron, manganese and magnesium as well as sulphur have been studied and compared with similar phenomena in two other local metal‐tolerant grasses, Cynodon dactylon and Trachypogon spicatus, as well as in some herbs and trees. The grasses accumulate high levels of copper in their roots in contrast with the herbaceous plants which accumulate the metal in their leaves. Distribution of other metals between roots and leaves is variable and is related to soil composition. Heavy‐metal tolerance in Stereochlaena cameronii does not appear to be dependent directly on sulphur or nitrogen metabolism. In S. cameronii from zinc‐rich soil, the zinc is largely in insoluble form in the roots, but in plants from other soils about half of this metal is in soluble form.
MINERAL NUTRITION OF LYCHNIS VISCARIA
Authors: JARVIS S. C. , PIGOTT C. D.
Published: May 2006

In Britain, Lychnis viscaria is restricted to shallow soils on outcrops of basic igneous rocks and, in experiments, seedlings grow well on these soils but fail on soils from outcrops of sandstone, limestone and acid igneous rocks. The growth of seedlings in water‐culture with purified salts shows that the species does not require an unusual balance of ions and its response to trace‐elements is normal. Seedlings will only grow on acid soils (other than on basic igneous rocks) if calcium carbonate, nitrogen, potassium and phosphate are provided, and on calcareous soils if phosphate is provided. There is evidence that L. viscaria can obtain phosphate from soils on basic igneous rocks even though other species show severe deficiency.
LIMITING FACTORS IN PHOTOSYNTHESIS
Authors: JONES HAMLYN G.
Published: May 2006

The limitations of present methods for describing the relative importance of different processes in controlling rates of photosynthesis are discussed, and a new method proposed. It is suggested that‘photosynthetic limitations’, instead of resistances, should be used to describe the relative importance of different component processes at normal ambient carbon dioxide concentrations. The limitation approach is particularly relevant if the photosynthetic rate is not limited entirely by the supply of carbon dioxide.
A CONSERVATION DATA BASE
Authors: RADFORD G. L. , PANKHURST R. J.
Published: May 2006

There is an urgent need to examine the range of ecosystems that is currently protected in national parks and reserves, to point out those examples that are unprotected and to establish a rational programme of priorities for protecting as complete a series as possible. The International Biological Programme has pioneered the field of large‐scale survey work for the collection of data of relevance to this need and has contributed to the development of information retrieval techniques for handling the data. The first part of the paper discusses the rationale of the development of the data base and its modus operandi. The system is illustrated by two examples of retrieval and analysis for specific enquiries; the distribution of four species of Pinus, and the occurrence of grazing, logging and burning in national parks and equivalent reserves in the United States. The second part of the paper deals with system design, details of programming for the data base, and retrieval strategy. It is intended as an independent section which may be skipped if the reader has no interest in the finer points of the data base itself.
NOTABLE PLANT RECORDS FROM THE CROMER FOREST BED SERIES
Authors: WILSON D. GAY
Published: May 2006

A number of new plant records are described from deposits of the Cromer Forest Bed Series of East Anglia. Each species is discussed in relation to its context and to its stratigraphical position within the series. Some aspects of the flora as a whole are provisionally described.
GROWTH FACTORS PRODUCED BY GAMETOPHYTES OF POLYPODIUM VULGARE L. GROWN UNDER RED AND BLUE LIGHT
Authors: SMITH D. L. , ROBINSON P. M. , GOVIER R. N.
Published: May 2006

Filtrates from gametophyte cultures of Polypodium vulgare L. grown under red or blue light contain several substances affecting gametophyte development. Chromatograms prepared from red‐light‐grown cultures show two separate zones of inhibition while those from blue‐light‐grown cultures show a broad zone of promotive activity and a zone of inhibition. All the zones of activity affect spore germination, cell division and the transition to two‐dimensional growth. None affects cell length but the inhibitors cause a reduction in cell width. Most of the known effects of red and blue light on gametophyte morphogenesis can be interpreted in terms of the activity of these substances.
TRANSLOCATION AND DISTANCE I. THE GROWTH OF THE FRUIT OF THE SAUSAGE TREE, KIGELIA PINNATA
Authors: CANNY M. J.
Published: May 2006

The dependence of rate of translocation on the distance between source and sink was investigated. The relationship previously predicted was tested by measuring the rate of growth of sausage fruits on different lengths of stalk. It was shown that the measured rates of translocation were not at variance with the predictions, and that the spectacular fruit growth can be accounted for by the massive development of secondary phloem in the fruit stalk which need function at a level that is quite moderate compared with other known systems. The parameters of the theoretical curve needed to fit the data are fully consistent with those measured by independent techniques in other translocating systems.
THE ASSAY OF NITRATE REDUCTASE IN WHOLE CELLS OF CHLORELLA: STRAIN DIFFERENCES AND THE EFFECT OF CELL WALLS
Authors: SYRETT P. J. , THOMAS E. M.
Published: May 2006

Strains of Chlorella with a sporopollenin‐like layer in their cell‐walls differ from strains without this layer in that their chlorophyll is extracted poorly by ethanol and they fail to stain with aniline blue. Exogenous NADH is not used as an election donor for nitrate reduction by frozen/thawed organisms having this layer and it is concluded that the layer impedes the passage of NADH; malate, which presumably reduces NADH held within the cell walls, is an effective electron donor for nitrate reduction. Frozen/thawed organisms of strains without this layer in their walls reduce nitrate when NADH is added. All the tested strains with this layer and the associated properties have been classified on other criteria as belonging to C. fusca var. vacuolata; the other strains examined have been classified as C. vulgaris or C. saccharophila.
BIOCHEMICAL AND PHYSIOLOGICAL ASPECTS OF LEAF DEVELOPMENT IN COCOA (THEOBROMA CACAO) I. DEVELOPMENT OF CHLOROPHYLL AND PHOTOSYNTHETIC ACTIVITY
Authors: BAKER N. R. , HARDWICK K.
Published: May 2006

Periodicity of leaf origin, rapid leaf expansion and lack, of significant chlorophyll synthesis in expanding leaves of cocoa (Theobroma cacao) are unusual features of leaf development. Changes in chlorophyll content, photosynthetic activity and ribulose‐i1,5‐diP carboxylase activity were determined during flush leaf development. Chlorophyll synthesis was found to be closely related to leaf expansion. Photosynthesis per unit area, photosynthesis per unit chlorophyll and ribulose‐i,5‐diP carboxylase activity all developed in parallel with chlorophyll. The significance of these findings is evaluated with regard to current concepts of photosynthetic unit development. Particular features of flush leaf development suggest that cocoa is a useful plant in which to examine the role of hormones and other factors in the control of chloroplast development.
OXYGEN—POSITIVE CHEMOTROPIC FACTOR FOR FUNGI?
Authors: ROBINSON PETER M.
Published: May 2006

Tropisms related to the point of emergence of germ‐tubes and to the subsequent direction of growth of germ‐tubes have been considered to be due to labile negative chemotropic factors produced by germinating spore populations. In many assay systems used to demonstrate chemotropic responses of germinating spores the oxygen concentration in the system would be the factor most likely to inhibit growth and evidence is presented which indicates that some of these responses could be caused by a positive chemotropism to oxygen. It is suggested that marked tropic responses to oxygen occur when the oxygen concentration begins to limit spore germination and extension‐growth of the emergent germ‐tubes and a hypothesis is presented to explain the mechanism of these effects.
THE GEOMETRY OF PLANT EPIDERMAL CELLS
Authors: KORN ROBERT W. , SPALDING RICHARD M.
Published: May 2006

Six monolayer tissues from various plants were studied for the number of anticlinal walls of non‐marginal, unspecialized cells. One class of tissues, including the abaxial epidermis of the scale of Allium cepa, the adaxial epidermis of the leaf of Euonymus fortunei var. vegetus, gametophytic cells of Dryopteris filix‐mas, and the surface cells of the bud of Anacharis demo, is characterized by (a) a probability distribution curve with a peak at six walls having a frequency of around 0.40, and (b) tissue growth in two directions. A second class of tissues has the distribution peak of six walls at an approximate frequency of 0.58 and is formed by growth in either one dimension or with regular alternation in two directions, as in the leaf of Anacharis densa and for the colony of Volvox aureus.

Models for both classes of tissues were constructed in order to identify those features associated with tissue proliferation that contribute to the variability of cell geometry. Geometric models give a pictorial representation of cell arrangement and are useful in ascertaining cell division patterns whereas algebraic models aid in clarifying spatial relationships between cells. The distinction between packing types and developmental types of models is discussed in the light of the concept of form in plant morphology.
ON THE ETHYLENE‐AUXIN INTERACTION IN GROWTH CONTROL
Authors: MER C. L.
Published: May 2006

Summary

The evidence on which this proposal was made has been examined and found unconvincing. An alternative interpretation of the data is suggested, which is amenable to a simple experimental test.
PLANT GROWTH RESPONSES TO VESICULAR‐ARBUSCULAR MYCORRHIZA VII. GROWTH AND MODULATION OF SOME HERBAGE LEGUMES
Authors: CRUSH J. R.
Published: May 2006

Summary

In phosphate‐deficient soils, VA mycorrhizas strongly stimulated nodulation and growth of Centrosema pubescent, Stylosanthes guyanensis, Trifolium repens and Lotus pedunculatus. The tropical legumes were much more dependent on mycorrhizas for growth than the temperate species and this difference seems to be related to the degree of root hair development. When Trifolium repens and Lolium perenne were grown together, mycorrhizas preferentially stimulated growth of the legume.
CARBOHYDRATE METABOLISM IN HEALTHY AND RUSTED LEAVES OF COLTSFOOT
Authors: HOLLIGAN P. M. , CHEN C. , McGEE E. E. M. , LEWIS D. H.
Published: May 2006

Summary

Infection of leaves of Tussilago by Puccinia poarum results in decreased export of photosynthetic products and, when infection is severe, in increased import. Photosynthetic products move to infection sites where host metabolites are converted to specific fungal products, including mannitol, arabitol, trehalose, glycogen, glucomannan and lipids. More previously fixed 14C is translocated to the fungus in the dark than in the light since, in the dark, degradation of starch contributes to net movement of 14C.
THE THREE‐DIMENSIONAL SHAPE OF PLANT CELLS AND ITS RELATIONSHIP TO PATTERN OF TISSUE GROWTH
Authors: KORN ROBERT W.
Published: May 2006

Summary

Two geometric models were devised for the shape of plant cells, one for those cells undergoing three‐dimensional expansion and the other for cells enlarging in one dimension (elongation). Probability distributions for the number and shape of wall facets were generated from the models and compared favourably with those found for real cells by other investigators. The i‐D growth model gave averages for the facet number and geometry of cells at interphase, division and daughter cell formation that closely approximated the averages from data collected by previous workers. These two types of developmental models, that is, ones following the quantitative relationships between cells over several generations, have two advantages over the standard interpretation of cell shape as the expression of packing forces. First, shape is explicitly explained from defined positions of cell plates during divisions. Second, subtle features of cell shape have morphogenetic importance in revealing the recent history of a cell with respect to its growth and its ontogenetic relationship to neighbouring cells.
REGENERATION OF THE CAP OF PRIMARY ROOTS OF ZEA MAYS
Authors: BARLOW PETER
Published: May 2006

Summary

The entire cap can be removed from the apex of the primary root of Zea mays. When this is done the nuclei of cells of the quiescent centre are stimulated to synthesize DNA and subsequently enter mitosis; the labelling and mitotic indices reach maximum values 12 and 18 h, respectively, after decapping. Division of cells of the quiescent centre and their descendants leads to the regeneration of a new cap which is completed about 3‐4 days after decapping. At this time a new quiescent centre is also established. The development of a new cap is a consequence of the changes in the polarity of growth and division of cells at the apex. Quantitative data are presented of the changes in rates and planes of division of the cells involved in cap regeneration. The data suggest that cells of the quiescent centre, stimulated to divide by de‐capping, complete about four mitotic cycles before a new quiescent centre forms. Experiments in which decapped roots were grown in a solution of colchicine, to induce polyploid nuclei, also showed that cells of the quiescent centre have the potential to enter four or five successive mitotic cycles as, in the quiescent centre of roots so treated, nuclei with up to 64C DNA content were found after 4 days.

Mature cells of the cap of intact roots contain nuclei with an 8‐16C DNA content. In regenerating caps nuclei with an 8C DNA content were frequent on the fourth day after decapping. The pattern of [3H]glucose incorporation, as judged by quantitative autoradiography, by regenerating caps was compared with that by normal caps. On the fourth day of cap regeneration the patterns were similar. These two sets of results suggest that differentiation of the regenerating cap proceeds normally at the levels of both nucleus and cytoplasm.

It is suggested that the initials of the cap collumella constrain the growth of the cells that constitute the quiescent centre and this in some way slows their rate of mitosis. Removing the cap relieves the constraint to cell growth and allows cell division, thus providing the trigger for regeneration. The changes in the pattern of cells in the regenerating apex, that accompany the reorganization of a new cap and quiescent centre, are explained in terms of the stresses that the cells impose upon each other.
PACHYCAULY, VESSEL‐ELEMENTS, ISLANDS AND THE EVOLUTION OF ARBORESCENCE IN ‘HERBACEOUS’ FAMILIES
Authors: MABBERLEY D. J.
Published: May 2006

Summary

The literature on pachycaul wood anatomy is reviewed. A simple mathematical proof discrediting Carlquist's ‘Theory of paedomorphosis in dicotyledonous woods’ is presented. In contrast to Carlquist's notion of juvenile wood patterns in mature pachycaul plants, it is shown that the narrow‐pithed leptocauls have wood patterns much like those of the juvenile stages of pachycauls. Leptocauls do not become pachycaul on islands; arborescent plants in ‘herbaceous’ families on islands are more easily explained as derived from pachycaul microspermous ancestors undergoing tree‐building in isolation from competition on the continents.
RESPONSE OF TWO VERONICA SPECIES TO A SIMULATED WOODLAND LIGHT CLIMATE
Authors: FITTER A. H. , ASHMORE C. J.
Published: May 2006

Summary

Two species of Veronica, V. montana and V. persica, respectively a woodland perennial and an annual weed of disturbed ground, were grown in unshaded, neutral shaded, and far‐red light. The only effect on V. montana was on root growth and was similar in shaded and far‐red treatments, but V. persica showed a far‐red specific reduction in leaf area, as well as shading effects on several other parameters. When grown in deeper shade under a leaf canopy, the growth of V. persica was drastically reduced and its developmental pattern radically altered, whilst that of V. montana was much more stable. It is suggested that the adaptation of V. montana to growth in woods involves resistance to both low light intensity and enhanced far‐red light stresses.
PHOSPHOLIPIDS AND PLANT MEMBRANE PERMEABILITY
Authors: Simon E. W.
Published: May 2006

Current views on membrane construction are presented as a basis for discussing certain modifications of structure that may render membranes leaky, allowing solutes to diffuse from them. Biophysical experiments on dehydrated membranes indicate that, when their water content is reduced below 20%, they no longer adopt the lipid bilayer conformation. When dry seeds, spores or lichens are placed in water, soluble cell constituents leak from them for a few seconds or minutes until membrane integrity is re‐established; the same may apply also to the liberation of solutes from pollen grains. Moreover, there are indications that ‘dry’ in this context means having less than about 20% water.

Some plants are sensitive to chilling, their tissues becoming leaky when exposed to temperatures between 0 and 10°C. This chilling‐induced leakage, attributed to a phase change in all the phospholipids of which the membrane is composed occurs at a slightly lower temperature than the change in the activation energy of membrane‐bound enzymes.

At senescence, leaf tissues become leaky and may eventually dry out. So much phospholipid disappears from senescing cotyledons of cucumber that there is no longer sufficient to fabricate complete and intact membranes around the cells. Treating cucumber cotyledons with iodoacetate also causes a loss of phospholipids, allowing solutes to leak out of the cells.

It is possible that exposing seeds or mature plant tissues to oxygen at pressures of 1 or more atm renders them leaky because of lipid peroxidation.