Fourier transform infrared spectroscopy as a non-destructive method for analysing herbarium specimens.

Dried plant specimens stored in herbaria are an untapped treasure chest of information on environmental conditions, plant evolution and change over many hundreds of years. Owing to their delicate nature and irreplaceability, there is limited access for analysis to these sensitive samples, particularly where chemical data are obtained using destructive techniques. Fourier transform infrared (FTIR) spectroscopy is a chemical analysis technique which can be applied non-destructively to understand chemical bonding information and, therefore, functional groups within the sample. This provides the potential for understanding geographical, spatial and species-specific variation in plant biochemistry. Here, we demonstrate the use of mid-FTIR microspectroscopy for the chemical analysis of Drosera rotundifolia herbarium specimens, which were collected 100 years apart from different locations. Principal component and hierarchical clustering analysis enabled differentiation between three main regions on the plant (lamina, tentacle stalk and tentacle head), and between the different specimens. Lipids and protein spectral regions were particularly sensitive differentiators of plant tissues. Differences between the different sets of specimens were smaller. This study demonstrates that relevant information can be extracted from herbarium specimens using FTIR, with little impact on the specimens. FTIR, therefore, has the potential to be a powerful tool to unlock historic information within herbaria.

Red trap colour of the carnivorous plant Drosera rotundifolia does not serve a prey attraction or camouflage function.

The traps of many carnivorous plants are red in colour. This has been widely hypothesized to serve a prey attraction function; colour has also been hypothesized to function as camouflage, preventing prey avoidance. We tested these two hypotheses in situ for the carnivorous plant Drosera rotundifolia. We conducted three separate studies: (i) prey attraction to artificial traps to isolate the influence of colour; (ii) prey attraction to artificial traps on artificial backgrounds to control the degree of contrast and (iii) observation of prey capture by D. rotundifolia to determine the effects of colour on prey capture. Prey were not attracted to green traps and were deterred from red traps. There was no evidence that camouflaged traps caught more prey. For D. rotundifolia, there was a relationship between trap colour and prey capture. However, trap colour may be confounded with other leaf traits. Thus, we conclude that for D. rotundifolia, red trap colour does not serve a prey attraction or camouflage function.

Reliance on prey-derived nitrogen by the carnivorous plant Drosera rotundifolia decreases with increasing nitrogen deposition.

• Carnivory in plants is presumed to be an adaptation to a low-nutrient environment. Nitrogen (N) from carnivory is expected to become a less important component of the N budget as root N availability increases. • Here, we investigated the uptake of N via roots versus prey of the carnivorous plant Drosera rotundifolia growing in ombrotrophic bogs along a latitudinal N deposition gradient through Sweden, using a natural abundance stable isotope mass balance technique. • Drosera rotundifolia plants receiving the lowest level of N deposition obtained a greater proportion of N from prey (57%) than did plants on bogs with higher N deposition (22% at intermediate and 33% at the highest deposition). When adjusted for differences in plant mass, this pattern was also present when considering total prey N uptake (66, 26 and 26 µg prey N per plant at the low, intermediate and high N deposition sites, respectively). The pattern of mass-adjusted root N uptake was opposite to this (47, 75 and 86 µg N per plant). • Drosera rotundifolia plants in this study switched from reliance on prey N to reliance on root-derived N as a result of increasing N availability from atmospheric N deposition.

Environmental differences between sites control the diet and nutrition of the carnivorous plant Drosera rotundifolia.

BACKGROUND AND AIMS: Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for Drosera rotundifolia L. METHODS: We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.62 g m-2 yr.-1, 353 µg l-1), Whixall Moss (1.37 g m-2 yr.-1, 1505 µg l-1). The total N amount per plant and the contributions of prey/root N to the plants' N budget were calculated using a single isotope natural abundance method. RESULTS: Plants at Whixall Moss invested less in carnivory, were less likely to capture prey, and were less reliant on prey-derived N (25.5% compared with 49.4%). Actual prey capture did not differ between sites. Diet composition differed - Cors Fochno plants captured 62% greater proportions of Diptera. CONCLUSIONS: Our results show site-level differences in plant diet and nutrition consistent with differences in resource availability. Similarity in actual prey capture may be explained by differences in leaf stickiness and prey abundance.

Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia.

Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant-prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific.

Cytochemically assayable Na+,K+-ATPase inhibition by Milan hypertensive rat plasma.

The ability of plasma from 3- and 9-week-old Milan hypertensive rats and their normotensive controls to inhibit Na+,K+-adenosine triphosphatase (ATPase) was studied using cytochemical bioassay techniques in fresh tissue. With a validated cytochemical bioassay that measures the capacity of biological samples to stimulate glucose-6-phosphate dehydrogenase activity in guinea pig proximal tubules as an indication of their capacity to inhibit Na+,K+-ATPase, the mean glucose-6-phosphate dehydrogenase-stimulating ability of the plasma of the 9-week-old Milan hypertensive rats and their normotensive controls was 586.0 +/- 88 and 23.4 +/- 8.3 U/ml (n = 7; p less than 0.001), while that of the 3-week-old Milan hypertensive rats (before the main rise in arterial pressure) and their normotensive controls was 99.9 +/- 27.4 and 7.8 +/- 1.8 U/ml (n = 7; p less than 0.001). With the use of a semiquantitative cytochemical assay that measures Na+,K+-ATPase activity directly, plasma from the adult hypertensive rats had a much greater capacity to inhibit Na+,K+-ATPase than the plasma of the control rats. The significantly raised levels found in the young hypertensive rats before the main rise in arterial pressure are consistent with the hypothesis that the rise in the ability of plasma to inhibit Na+,K+-ATPase is due to an inherited renal difficulty in excreting sodium.

Ouabainlike Na+,K+-ATPase inhibitor in the plasma of normotensive and hypertensive humans and rats.

Acute volume expansion, increased sodium intake, and restraint on sodium excretion endow the plasma with an increased capacity to inhibit sodium transport. Cytochemical techniques can detect the presence of Na+K+-adenosine triphosphatase (ATPase) inhibitor in the plasma of normal humans and rats, the concentration of which is controlled by salt intake. The substance responsible appears to originate in the hypothalamus, where the concentration is also controlled by salt intake. The plasma concentration of the cytochemically detectable Na+,K+-ATPase inhibitor is substantially raised in the plasma of patients with essential hypertension, spontaneously hypertensive rats (SHR) and of Milan hypertensive rats. The concentration of activity in the hypothalamus of SHR is also considerably raised. These findings demonstrate that these forms of hypertension are associated with a rise in the concentration of a cytochemically detectable circulating Na+,K+-ATPase inhibitor that under normal circumstances is controlled by salt intake.

Na-K-ATPase-inhibiting and glucose-6-phosphate dehydrogenase-stimulating activity of plasma and hypothalamus of the Okamoto spontaneously hypertensive rat.

The plasma of normal man and the rat, and an acetone extract of hypothalamus from the rat, have an ability to inhibit Na-K-ATPase which is related directly to salt intake. The ability of the plasma to inhibit Na-K-ATPase is raised in essential hypertension. The ability of plasma and of an acetone extract of hypothalamus from six spontaneously hypertensive (SHR) rats and six normotensive control (WKY) rats to inhibit Na-K-ATPase of fresh guinea-pig kidney was studied using cytochemical bioassay techniques. With a validated assay, which measures the capacity of biological samples to stimulate glucose-6-phosphate dehydrogenase (G6PD) as an index of their capacity to inhibit Na-K-ATPase, the mean G6PD-stimulating ability of the plasma from the SHR and the WKY rat was 772.3 +/- 48.1 units/ml and 12.5 +/- 2.6 units/ml respectively (P less than 0.01) and of the hypothalamic extracts it was 2.2 +/- 1.7 X 10(8) and 4.5 +/- 1.8 X 10(4) units/hypothalamus (P less than 0.01). With a semi-quantitative cytochemical assay, which measures Na-K-ATPase activity directly, plasma and an acetone extract of hypothalamus from the spontaneously hypertensive rat had much greater capacities to inhibit Na-K-ATPase than plasma and extract from the WKY rat. These raised levels of Na-K-ATPase inhibitory activity in the plasma of the SHR rat are similar to the highest values found in the plasma of patients with essential hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Extraction and characterization of a cytochemically assayable Na+/K+-ATPase inhibitor/glucose-6-phosphate dehydrogenase stimulator in the hypothalamus and plasma of man and the rat.

Some physicochemical properties of partially purified hypothalamic material from the spontaneously hypertensive rat, and of plasma from man and the rat, have been characterized using a validated cytochemical bioassay which measures the ability of biological fluids to stimulate fresh guinea-pig kidney glucose-6-phosphate dehydrogenase (G6PD) after 2 min of exposure to the test substance, as an indication of their ability to inhibit Na+/K+ adenosine triphosphatase (Na+/K+-ATPase) after 4-6 min of exposure. The G6PD-stimulating activity of both hypothalamic extract and plasma is soluble in water and insoluble in chloroform. During electrophoresis the activity from both sites appears in the same fractions and travels considerably further than lysine. After high-pressure liquid chromatography the activity of hypothalamic extract appears in a discreet fraction which does not absorb u.v. light. The activity of both the hypothalamic extract and plasma survives boiling and acid hydrolysis, but is substantially inhibited by prior incubation with digoxin antibody. From ultrafiltration studies, the substance responsible for the ability to stimulate G6PD appears to have a molecular weight of less than 500. The G6PD-stimulating activity of hypothalamic extracts was destroyed by ashing and by base hydrolysis. The ability of plasma of high activity to stimulate G6PD is considerably increased by incubating at 37 degrees C for 15 min and destroyed by incubation for 45 min. It is concluded that these and several other previously noted similarities suggest that the cytochemically assayable Na+/K+-ATPase-inhibiting/G6PD-stimulating activity in the plasma and hypothalamus may be due to the same ouabain-like substance.

Evidence that the hypothalamus may be a source of a circulating Na+-K+-ATPase inhibitor.

Acetone extracts from a variety of rat tissues were tested for their ability to stimulate renal glucose-6-phosphate dehydrogenase (G6PD) activity at 2 min in an in-vitro cytochemical assay which is a marker of the sodium potassium-dependent adenosine triphosphatase (Na+-K+-ATPase) inhibiting activity. Extracts of the hypothalamus were the only ones found to be active in this system. Acetone extract of hypothalamus also inhibited renal Na+-K+-ATPase activity in vitro. The G6PD-stimulating activity from one hypothalamus was about 10000 to 100000 times greater than that of 1 ml plasma. The G6PD-stimulating activity of hypothalamic extracts from rats which had been on a high sodium intake for 4 weeks were approximately 150 times more active than those obtained from rats which had been on a low sodium diet. The G6PD-stimulating activity of the corresponding plasma was sixfold more active. These findings suggest that a circulating sodium transport inhibitor(s) may be secreted from the hypothalamus.

Cytochemically detectable glucose-6-phosphate dehydrogenase-stimulating/Na-K-ATPase-inhibiting activity of plasma and hypothalamus in reduced renal mass hypertension.

Plasma from normal humans and rats on a high sodium intake, and from patients and rats suffering from hereditary hypertension has an increased cytochemically detectable glucose-6-phosphate dehydrogenase (G6PD)-stimulating/Na-K-ATPase inhibiting activity. The hypothalamic content of this activity is also increased by a high sodium intake and in the spontaneously hypertensive rat (SHR). Using cytochemical techniques, the ability of plasma and the hypothalamus of reduced renal mass hypertensive rats to stimulate G6PD activity and to inhibit Na-K-ATPase was measured. The mean G6PD-stimulating capacity of the plasma from the hypertensive and normotensive groups of rats was 351 +/- 67 and 11.42 +/- 1.98 G6PD-stimulating units/mL respectively (P less than .001). The time courses of the ability of plasma from a hypertensive and a normotensive rat to inhibit fresh tissue Na-K-ATPase after 2, 4, 6, and 8 min of exposure demonstrated that the hypertensive rat plasma had a greater capacity to inhibit Na-K-ATPase. The mean G6PD-stimulating capacity of the hypothalamus from the hypertensive and normotensive groups of rats was 252,263 +/- 147,958 X 10(3) and 6.38 +/- 2.35 X 10(3) G6PD-stimulating units per hypothalamus, respectively (P less than .01). It is proposed that the raised concentration of cytochemically detectable G6PD-stimulating/Na-K-ATPase-inhibiting substance in both genetic and nongenetic forms of hypertension may be a manifestation of a communal hypertensinogenic mechanism. Thus, the raised plasma concentration would have a direct peripheral vascular constricting effect and the high hypothalamic concentration would be responsible for a central nervous hypertensinogenic effect.

Feulgen-hydrolysis profiles in cells exfoliated from the cervix uteri: a potential aid in the diagnosis of malignancy.

By varying the time of hydrolysis for the Feulgen reaction, done under conditions that protect the backbone of the DNA, it is possible to distinguish three species of DNA that are characterised by their lability to acid hydrolysis. The most labile DNA was found, in greatest proportions, in malignant cells; this may be helpful in diagnostic cytology. The fact that the cytologically normal cells, in grade V smears, also show this labile DNA may well facilitate cytological screening even in those smears that contain very few neoplastic cells.

Lysosomal naphthylamidase activity as a possible aid in cytological screening.

Lysosomal naphthylamidase activity has been measured microdensitometrically in cells in samples obtained by cervical and vaginal irrigation from 22 cases cytologically graded I and II, 28 graded III (moderate to severe dysplasia), 22 graded IV (carcinoma in situ), and 15 cases (grade V) of invasive carcinoma. There was a statistically significant difference in this activity in the cells from cases of grade V as against those in the relatively normal samples (grades I and II; p < 0.001) and as against those of grade IV (p < 0.005). The method is sufficiently robust for routine use provided that it is recognised that elevated activities can be found as a consequence of other factors such as previous surgical intervention and infection with herpes simplex.

Reorganization of a burn unit in response to underutilization: a critical assessment.

The incidence of burn injury in the United States has declined over the past few years, resulting in a dramatic decrease in the number of admissions to burn centers. This decrease has generated considerable concern, leading to a variety of proposals to modify burn units to control the cost of inpatient care. In 1986 Albany Medical Center Hospital, a 654-bed regional academic health sciences center, closed its burn unit and implemented a program to manage thermally injured patients in the intensive and progressive care areas of the medical center. A retrospective study was performed to compare patient outcomes and length of stay for the dedicated burn unit and the integrated burn program. Between the year before and the year after this change there was no significant difference in mortality rate, length of stay, or number of positive blood cultures. The relationship between burn severity and length of stay was unaltered by the burn program change. A comparison of data collected just after the change to those collected 2 years later again showed no difference, except that the annual census had dropped more than 50%. The results suggest that burn units can be converted to integrated burn programs without compromising patient care outcomes, although the lack of a cohesive burn team and the unavailability of beds designated for patients with burns ultimately resulted in a deemphasis of the burn program and consequent marked reduction in the number of patients with burns seen in the institution.

Do competition and herbivory alter the internal nitrogen dynamics of birch saplings?

Deciduous trees recycle nitrogen within their tissues. The aim of this study was to test the hypothesis that reductions in plant growth, caused by competition and herbivory, reduce the sink strength for N during autumn nutrient withdrawal, and reduce the storage capacity and hence the amount of N remobilized in the following spring. We used (15)N-labelled fertilizer to quantify N uptake, leaf N withdrawal and remobilization. Betula pubescens saplings were grown with either Molinia caerulea or Calluna vulgaris, and subjected to simulated browsing damage. Competition reduced B. pubescens leaf N withdrawal and remobilization, with C. vulgaris having a greater effect than M. caerulea. However, simulated browsing had no significant effect on sapling N dynamics. The patterns of leaf N withdrawal and remobilization closely followed sapling dry mass. We conclude that the effect of competition on sapling mass reduces their N-storage capacity. This reduces sink strength for leaf N withdrawal and the source strength for remobilized N. The ability of saplings to compensate for browsing damage removed any potential effect of browsing on N dynamics.