Randomized clinical trial of Appendicitis Inflammatory Response score-based management of patients with suspected appendicitis.

BACKGROUND: The role of imaging in the diagnosis of appendicitis is controversial. This prospective interventional study and nested randomized trial analysed the impact of implementing a risk stratification algorithm based on the Appendicitis Inflammatory Response (AIR) score, and compared routine imaging with selective imaging after clinical reassessment. METHOD: Patients presenting with suspicion of appendicitis between September 2009 and January 2012 from age 10 years were included at 21 emergency surgical centres and from age 5 years at three university paediatric centres. Registration of clinical characteristics, treatments and outcomes started during the baseline period. The AIR score-based algorithm was implemented during the intervention period. Intermediate-risk patients were randomized to routine imaging or selective imaging after clinical reassessment. RESULTS: The baseline period included 1152 patients, and the intervention period 2639, of whom 1068 intermediate-risk patients were randomized. In low-risk patients, use of the AIR score-based algorithm resulted in less imaging (19·2 versus 34·5 per cent; P < 0·001), fewer admissions (29·5 versus 42·8 per cent; P < 0·001), and fewer negative explorations (1·6 versus 3·2 per cent; P = 0·030) and operations for non-perforated appendicitis (6·8 versus 9·7 per cent; P = 0·034). Intermediate-risk patients randomized to the imaging and observation groups had the same proportion of negative appendicectomies (6·4 versus 6·7 per cent respectively; P = 0·884), number of admissions, number of perforations and length of hospital stay, but routine imaging was associated with an increased proportion of patients treated for appendicitis (53·4 versus 46·3 per cent; P = 0·020). CONCLUSION: AIR score-based risk classification can safely reduce the use of diagnostic imaging and hospital admissions in patients with suspicion of appendicitis. Registration number: NCT00971438 ( http://www.clinicaltrials.gov).

Morphological and physiological analysis of type-5 and other bipolar cells in the Mouse Retina.

Retinal bipolar cells are second-order neurons in the visual system, which initiate multiple image feature-based neural streams. Among more than ten types of bipolar cells, type-5 cells are thought to play a role in motion detection pathways. Multiple subsets of type-5 cells have been reported; however, detailed characteristics of each subset have not yet been elucidated. Here, we found that they exhibit distinct morphological features as well as unique voltage-gated channel expression. We have conducted electrophysiological and immunohistochemical analysis of retinal bipolar cells. We defined type-5 cells by their axon terminal ramification in the inner plexiform layer between the border of ON/OFF sublaminae and the ON choline acetyltransferase (ChAT) band. We found three subsets of type-5 cells: XBCs had the widest axon terminals that stratified at a close approximation of the ON ChAT band as well as exhibiting large voltage-gated Na(+) channel activity, type-5-1 cells had compact terminals and no Na(+) channel activity, and type-5-2 cells contained umbrella-shaped terminals as well as large voltage-gated Na(+) channel activity. Hyperpolarization-activated cyclic nucleotide-gated (HCN) currents were also evoked in all type-5 bipolar cells. We found that XBCs and type-5-2 cells exhibited larger HCN currents than type-5-1 cells. Furthermore, the former two types showed stronger HCN1 expression than the latter. Our previous observations (Ichinose et al., 2014) match the current study: low temporal tuning cells that we named 5S corresponded to 5-1 in this study, while high temporal tuning 5f cells from the previous study corresponded to 5-2 cells. Taken together, we found three subsets of type-5 bipolar cells based on their morphologies and physiological features.

Assessment of the AAV-mediated expression of channelrhodopsin-2 and halorhodopsin in brainstem neurons mediating auditory signaling.

The physiology and circuitry associated with dorsal cochlear nucleus neurons (DCN) have been well described. The ability to remotely manipulate neuronal activity in these neurons would represent a step forward in the ability to understand the specific function of DCN neurons in hearing. Although, optogenetics has been used to study the function of pathways in other systems for several years, in the auditory system only neurons in the auditory cortex have been studied using this technique. Adeno-associated viral vectors with either channelrhodopsin-2 fused with GFP (ChR2-GFP) or halorhodopsin fused with mCherry (HaloR-mCherry), capable of expressing light sensitive cation channels or chloride pumps, respectively, were delivered into the dorsal cochlear nucleus (DCN). One to 18 months later, expression of ChR2 and HaloR was observed throughout the DCN. Rhodopsin distribution within the DCN was determined to be within several cell types identified based on morphology and location within the DCN. Expression of ChR2-GFP and HaloR-mCherry was found at both the injection site as well as in regions receiving projections from the site. Wavelength appropriate optical stimulation in vivo resulted in neuronal activity that was significantly increased over pre-stimulation levels with no return to baseline levels during the time of the light exposure. We also examined the effects of optically driven neuronal activity on subsequent tone driven responses in the DCN. In the DCN 75% of the 16 electrode sites showed decreased neuronal activity in response to a tone immediately following light stimulation while six percent were decreased following tone stimulation and 19% of the electrode sites showed no change. This is in contrast to tone driven neuronal activity prior to the light exposure in which the majority of electrode sites showed increased neuronal activity. Our results indicate that expression and activation of rhodopsin within neurons involved in auditory processing does not appear to have deleterious effects on hearing even 18 months following expression. In addition, virally targeted rhodopsins may be useful as tract tracers to delineate as well as modulate the activity of pathways and specific neurons. In the future rhodopsins can be targeted to specific subpopulations of auditory neurons. Ultimately, photostimulation may provide a physiologically relevant method for modulating the function of auditory neurons and affecting hearing outcomes. This article is part of a Special Issue entitled Optogenetics (7th BRES).

Vesicular glutamate transporters: spatio-temporal plasticity following hearing loss.

An immunocytochemical comparison of vGluT1 and vGluT3 in the cochlear nucleus (CN) of deafened versus normal hearing rats showed the first example of vGluT3 immunostaining in the dorsal and ventral CN and revealed temporal and spatial changes in vGluT1 localization in the CN after cochlear injury. In normal hearing rats vGluT1 immunostaining was restricted to terminals on CN neurons while vGluT3 immunolabeled the somata of the neurons. This changed in the ventral cochlear nucleus (VCN) 3 days following deafness, where vGluT1 immunostaining was no longer seen in large auditory nerve terminals but was instead found in somata of VCN neurons. In the dorsal cochlear nucleus (DCN), while vGluT1 labeling of terminals decreased, there was no labeling of neuronal somata. Therefore, loss of peripheral excitatory input results in co-localization of vGluT1 and vGluT3 in VCN neuronal somata. Postsynaptic glutamatergic neurons can use retrograde signaling to control their presynaptic inputs and these results suggest vGluTs could play a role in regulating retrograde signaling in the CN under different conditions of excitatory input. Changes in vGluT gene expression in CN neurons were found 3 weeks following deafness using qRT-PCR with significant increases in vGluT1 gene expression in both ventral and dorsal CN while vGluT3 gene expression decreased in VCN but increased in DCN.

Simvastatin modulates TNFalpha-induced adhesion molecules expression in human endothelial cells.

Adhesion and transendothelial migration of leukocytes into the vascular wall is a crucial step in atherogenesis. Expression of cell adhesion molecules by endothelial cells plays a leading role in this process. We investigated the effect of simvastatin, an inhibitor of HMG-CoA reductase administered to reduce plasma levels of LDL-cholesterol, on the expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) by human umbilical vein endothelial cells (HUVEC) stimulated with tumor necrosis factor alpha (TNFalpha). We found the expression to be significantly inhibited by the drug in a time and concentration-dependent manner and to a greater extent in the case of VCAM-1 as compared with ICAM-1. In TNFalpha-stimulated HUVEC, simvastatin decreased VCAM-1 and ICAM-1 mRNA levels, inhibited TNFalpha-induced activation of nuclear factor kappaB (NF-kappaB) and enhanced expression of peroxisome proliferator-activated receptor alpha (PPARalpha). These effects were associated with reduction of adherence of monocytes and lymphocytes to HUVEC. The present findings suggest that the benefits of statins in vascular disease may include the inhibition of expression of VCAM-1 and ICAM-1 through effects on NF-kappaB.

Humoral and cellular immunity rates in chemical plant workers producing dust pesticides.

BACKGROUND: Exposure to pesticides may affect humoral and cell-mediated immunity. MATERIAL AND METHODS: The study group was composed of 24 men employed in the production of dust pesticides and 23 females performing ancillary jobs under conditions of lower pesticide exposure. Chronic bronchitis was diagnosed in 10 males (41.7%) and 13 females (56.5%). The workers were exposed to: triazines, carbamates and dithiocarbamates, carbendazim, captan, dodine, dichlorophenoxy acetic acid (2,4-D), and cupric oxychloride. Silica, kaolin, chalk, and talc were used as carriers. The average workplace air concentrations of pesticides did not exceed the MAC. The serum concentrations of immunoglobulins G, A and M, complement component C3, and circulating immune complexes (CIC) were estimated. The peripheral blood leukocyte count and percentage of CD3, CD4, CD8, CD19 lymphocytes were evaluated. RESULTS: IgA and CIC concentrations in the female group were higher as compared to controls, whereas the percentage of CD3, CD4, CD8 cells was significantly lower, as opposed to an increased percentage of CD19 cells. The male group showed lower CIC concentrations, and the C3 complement component level was significantly higher. The decreased percentage of CD3 cells was accompanied by a higher CD19 cells ratio. The white blood cell count was higher in the males. No significant changes were found in other immunity parameters. CONCLUSIONS: The results of the study showed changes in some components of humoral and cellular immunity, which may influence damage to the respiratory system.

[Renal dysfunction in chemical plant workers producing dust pesticides]. / Dysfunkcja nerek u pracowników zakladu chemicznego produkujacych pyliste srodki ochrony roslin.

The study covered workers of a chemical plant producing dust pesticides. A study group included 24 men, aged 29-54 years, employed directly in the production, and 22 women, aged 31-52 years, performing auxiliary jobs and handling only closed packages. In order to assess the renal function in the workers, the concentrations of serum creatinine and uric acid, protein, albumin and alpha 1-microglobulin, as well as the activity of alkaline phosphatase (AP) and N-acetyl-beta-glucosaminidase (NAG) in urine were determined. The average air dust concentration at the workplaces was 0.42-16.66 mg/m3. The active substances with concentrations ranging from 10 to 75% in the final product were as follows: triazines, dithiocarbamates, carbendazim and thiophanate-methyl, captan, phenylureas, cupric oxychloride and occasionally also carbamates, dodine and 2,4-D. As compared to the results in the control groups of 31 healthy men and 22 women, free from occupational exposure to chemical noxas, a significantly higher serum creatinine concentration (in none of the subjects creatinine concentration exceeded the upper normal limit) and higher urinary protein, albumin and alpha 1-microglobulin concentrations, and higher enzyme activity were found in men, while in women only urine enzyme activity was significantly increased. The results speak in support of a discreet subclinical kidney impairment.

[Thyroid gland function after therapy of the laryngeal cancer: prospective examinations]. / Funkcja hormonalna tarczycy po leczeniu raka krtani--badania prospektywne.

The paper presents the results of the study concerning thyroid gland function of the patients suffering from larynx cancer treated with: a) surgery only (n = 31), b) surgery with further radiotherapy with radical doses 5400-7000 cGy (n = 44), c) radiotherapy along with radical doses 6400-7000 cGy (n = 7). 82 patients (M-73, F-9) were examined. Average age was 58 (min. 30, max. 80). Thyroid gland function was evaluated by measurement of: a) hTSH, fT3, fT4, b) serum lipids concentration. The examinations mentioned above were performed before as well as after the treatment at: a) 1, b) 1-6, c) 6-12, d) 12-24, e) longer than 24 months after completion of treatment. The longest period of observation involved 8 years. Our results show that hypothyroidism (mostly subclinical) occurs seldom (6% of all the cases) in the early phase (up to 1 month) after surgical treatment. After radiotherapy only--no subclinical hypothyroidism was observed. The combined treatment seems to be the most frequent cause of subclinical hypothyroidism. Its frequency increases (up to 27%) with the length of time since the conclusion of treatment. We also tried to explain the pathogenesis of subclinical hypothyroidism on the basis of histopathologic examination of thyroid tissue (n = 13) derived from the patients after various ways of treatment. The studies were compared to the results of histological examinations of the thyroid sections obtained during autopsy (n = 20) from the control group (not suffered from thyroid diseases).

[Hormonal function of the thyroid gland after therapy for laryngeal cancer]. / Funkcja hormonalna tarczycy po leczeniu raka krtani.

The paper presents the results of the study concerning thyroid gland function of the patients suffering from larynx cancer treated with: a) surgery only, b) surgery with further radiotherapy with radical doses 5000-6500 cGy, c) radiotherapy along with radical doses 6500-7200 cGy. Thyroid gland function was evaluated by measurement of: a) hTSH, FT3, FT4, b) serum lipids concentration. The hTSH concentration was evaluated by immunoradiometric method whereas FT3 and FT4 by DELFIA techniques (deleted fluorescence). 162 patients (M-148, F-14) were examined. Average age was 57 (min.-30, max.-80). The patients were divided into two groups. The first group (n = 90) involved those who had been examined once at different time since the end of treatment (retrospective examinations). The patients who had been examined before as well as after treatment were established as the second group (n = 72) (prospective examinations). In this case the examinations are still being continued and they are carried out at: a) 1, b) 1-6, c) 6-12, d) 12-24, e) longer than 24 months after completion of treatment. Our preliminary data show that hypothyroidism (mostly subclinical) occurs seldom (7% of all the cases) in the early phase (up to 1 month) after surgical treatment and gets normal spontaneously (up to 6 months). After radiotherapy only--no subclinical hypothyroidism was observed. Interestingly, the combined treatment seems to be the most frequent cause of subclinical hypothyroidism. Its frequency increases (up to 47%) with the length of time since the conclusion of treatment (2 years and longer). Because of continuation of our examinations the presented data are still preliminary and they will be verified in the next paper. We also tried to explain the pathogenesis of subclinical hypothyroidism on the basis of histopathologic examination of thyroid tissue derived from the patients (after combined treatment and after radiotherapy) during further total laryngectomy performed because of neoplasm renewal.

5T4 oncofetal antigen in gastric carcinoma and its clinical significance.

OBJECTIVE: To evaluate the role of 5T4 antigen in gastric cancer progression and prognosis. DESIGN: A prospective study of 5T4 antigen expression in primary, secondary and recurrent gastric carcinoma, the relationship to selected prognostic parameters and the course of disease. PATIENTS: Eighty six patients operated on for gastric cancer. TISSUE: One hundred and twenty two gastric tumours were studied, including 86 primary carcinomas, 32 coexisting lymph node metastases and four recurrent carcinomas. METHODS: Immunohistochemistry using 5T4 monoclonal antibody on frozen sections. RESULTS: The 5T4 antigen was detected in 41% of primary gastric tumours including early gastric cancer. A strong relationship was found between 5T4 positivity and tumour histology. Thus, 52% of gastric carcinomas of intestinal type expressed 5T4 antigen compared with 28% of the diffuse type (P = 0.028). Among 16 sets of primary gastric carcinomas and regional lymph node metastases, coordinate 5T4 expression was seen in 14 cases; the other two showed acquisition of positivity on metastatic tumour cells (carcinomas of diffuse type). 5T4 antigen was detected more frequently in carcinomas with p53 accumulation compared with those with undetectable p53 levels (P = 0.015). The presence of 5T4 in cancer cells was correlated with poor short-term prognosis (24% vs 49% of 2 year survival for 5T4 positive and negative tumours respectively, P = 0.024). The effect on survival was evident in the p53 negative group, with patients 5T4 positive showing worse survival (28% vs 60% in 2 years). CONCLUSIONS: Our results suggest that the assessment of 5T4 expression in gastric carcinoma can be helpful in identifying patients with poor short-term prognosis.

Humoral and cellular immunity rates in chemical plant workers employed in the production of liquid pesticides.

In order to assess the immunological system of the chemical plant workers certain rates of cellular and humoral immunity were estimated. The study group was composed of 19 males employed in the production of liquid pesticides, and 18 females performing ancillary jobs and handling closed containers. They were alternatively exposed to phosphoroorganic compounds and pyrethroides, and to chlorinated hydrocarbons, carbamates, nitrophenols and organic solvents, however exposure to the latter was lower. Chronic bronchitis was observed in 7 (37%) males and 4 (22%) females. Serum concentrations of immunoglobulins G, A and M, complement protein Cs, and circulating immune complexes were estimated. The peripheral blood leukocyte count and percentage, the granulocyte adherence and phagocytic activity, spontaneous NBT-dye reduction as well as cytochemical reactions to alkaline and acid phosphatase, beta-glucuronidase, myeloperoxidase and catalase of neutrophils were evaluated; the lymphocyte subpopulations CD3, CD4, CD8, CD16 were also estimated. As compared to controls, a significantly increased serum IgG concentration was found, together with elevated IgM in males and IgA in females. The leukocyte count in males was significantly higher. A considerable decrease in the percentage of neutrophils was accompanied by a significantly greater spontaneous NBT-dye reduction in both groups. Neutrophil adherence impairment was observed in males. Cytochemical reactions to beta-glucuronidase and catalase in both sexes, to alkaline and acid phosphatase in females, and to myeloperoxidases in males were significantly lowered, whereas the reaction to acid phosphatase in males was significantly enhanced. The percentages of lymphocytes CD3, CD4 and the CD4/CD8 ratio were significantly decreased.

Spectral evidence for cytochrome o in the brown membrane of Halobacterium halobium.

The brown membrane domain of Halobacterium halobium is a developmental precursor of the purple membrane and it contains a b-type cytochrome in addition to bacterio-opsin. In this report we provide spectroscopic evidence that the majority of the cytochrome content is a halobacterial cytochrome o. This cytochrome has absorption spectral properties in the oxidized, reduced, and CO liganded states which are characteristic of cytochrome o. The CD spectra show a complex bilobed pattern in the Soret spectral region which reflects the similarity of the heme environment to those of other b-type cytochromes involved in electron transport. We have also demonstrated a positive cooperativity of CO binding which, combined with CD spectral results, suggests two interacting heme moieties per cytochrome o. Size exclusion HPLC of solubilized brown membrane preparations shows a heme b containing protein with an Mr 42,000-46,000. The cytochrome may be easily separated from bacterio-opsin using a hydroxyapatite elution method on Triton X-100 solubilized preparations. The relative ease with which brown membrane disks may be oriented in high optical quality films should make the brown membrane a valuable model system for future spectroscopic investigations of cytochrome o.

Role of the capsule produced by Bacillus megaterium ATCC 19213 in the accumulation of metallic cations.

A study was undertaken to determine if the capsule produced by Bacillus megaterium ATCC 19213 was capable of binding metallic ions. For non-toxic metallic ions, this was accomplished by determining the relative concentrations of Fe2+, Ca2+, Zn2+, Mg2+, and Mn2+ removed from a chemically defined medium by the normally capsulated parent strain and two mutants with much smaller capsules. For toxic metals, the rates of respiration of the parent strain and a small capsule mutant in the presence of Cu2+, Hg2+, and Ag1+ were compared. It was found that the parent strain accumulated more Ca2+, Mg2+, and Mn2+. Accumulation of Fe2+ and Zn2+ was similar for the parent strain and the small capsule mutants. Respiration of the parent strain was less inhibited by Cu2+, Hg2+, and Ag1+, indicating that these metals are also bound to the capsule.

Nonspecific immunosuppression by cultured lymphocyte supernates of cancer patients.

A nonspecific immunosuppressive factor, lymphocyte immunosuppive substance (LIS), has been correlated with cancer patients. Significant suppression of IgM antibody production of sheep erythrocyte immune Swiss mice lymphocytes was found when the immune lymphocytes were treated with cultured peripheral blood lymphocyte supernates of tumor-bearing patients. A lesser amount of LIS activity was also demonstrated with patients who had cancer in the past, but were clinically free of disease at the time of testing. This suppressive activity has been demonstrated with several solid tumors including breast CA, colon CA, melanoma, uterine CA, and ovarian CA. A possible use of this suppression test for detecting recurrences is suggested from the data.

Isolation and partial characterization of a glucose-binding protein from Bacillus megaterium.

Attempts were made to use the osmotic shock procedure established for Gram-negative micro-organisms on a Gram-positive micro-organisms, Bacillus megaterium ATCC 19213. The procedure did not appear to shock the cells osmotically. The procedure, in fact, appeared to enhance binding of both glucose and fructose by the organism. The binding of glucose was greater by cells, whether grown on fructose or glucose, than it was for fructose. A procedure was developed for removing and isolating a protein capable of binding glucose. This involved solubilizing the cytoplasmic membrane of the organism with the nonionic detergent Triton X-100, and then isolating it by gel filtration on a Bio-Gel A 1.5 column with 0.05 M pyrophosphate containing 1% (v/v) Triton X-100 as the eluting buffer. This is the first isolation of such a protein in a Gram-positive organism. Isolated protein was demonstrated to have a specificity only for glucose. The protein did not bind to either the monosaccharides fructose and galactose, or the disaccharide sucrose. This was in comparison to whole cells which demonstrated ability to take up fructose. The protein was estimated to have a molecular weight between 24,000 and 30,000 daltons by gel filtration techniques.

Morphological abnormalities of lymphocytes from patients with advanced solid tumours.

Characteristic morphological abnormalities were found to be present on lymphocytes from patients with advanced solid tumours. Numerous microprojections were characteristically present on human peripheral blood lymphocytes from cancer patients while non-cancer subject control lymphocytes ('normal' lymphocytes) appeared significantly smoother. Incubation of normal lymphocytes in cancer serum resulted in increased occurrence of these microprojections whereas incubation of normal cells in normal heterologous serum resulted in no apparent surface changes. Incubation of cancer lymphocytes in levamisole, an immunostimulant, did not abrogate surface projections.

Anti-tumour cytotoxicity of poly(A)-containing messenger RNA isolated from tumour-specific immunogenic RNA.

The transfer of tumour-specific cytotoxicity against a murine fibrosar-coma has been demonstrated in vitro using xenogeneic RNA extracted from tumour-cell-immune animals. Poly(A)-tailed messenger RNA from immunogenic RNA was isolated by passage through an oligo(dT)-cellulose column, and evaluated to determine whether the same tumour-specific cytotoxicity could be transferred. Aliquots of normal C3H mouse lymphocytes were treated with poly(A)-containing immune RNA, whole-cell immune RNA lacking poly(A) and total cellular immune RNA. Treated cells were tested in vitro using an adaptation of the Takasugi and Klein microcytotoxicity assay. Percent cytotoxicity was calculted using cells treated with fractions of normal RNA as control. An increase in tumour cytotoxicity was found with poly(A)-containing immune RNA. The optimum dose of poly(A)-tailed immune RNA was estimated as 6.5 microgram of RNA per 4 x 10(6) lymphocytes. Populations of lymphocytes were separated using glass and nylon wool. T- and B-enriched populations were treated with various RNA components. The adherent cell population showed no significant cytotoxicity, whilst treatment of the nonadherent population with poly(A)-tailed immune RNA produced high levels of cytotoxicity.

Ultrastructure of the capsule of Bacillus megaterium ATCC 19213.

The ultrastructure of the firmly adherent capsule produced by Bacillus megaterium cultured on fructose mineral salts medium was examined using thin sectioning, freeze-etching, and critical point drying by transmission and scanning electron microscopy. The capsule material was shown to be fibrillar, with most fibrils containing bulbous protrusions. Two types of fibres were resolved. These were termed primary and cross-linking fibres. Primary fibres originated at the cell wall and had a diameter of 34-50 nm. They also contained bulbous protrusions and enlarged areas where branching occurred. Cross-linking fibres connected the primary fibres. The cross-linking fibres were much smaller, usually 15 micro m in diameter, and contained few enlarged areas. The primary fibres originated at sites on the cell wall approximately equidistant and 0.26 micro m apart.

Divalent cation mobility throughout exponential growth and sporulation of Bacillus megaterium.

Each of the five elements considered was taken up by Bacillus megaterium during exponential growth. Initial Mg and Mn uptake was rapid and ended by mid-log. For Ca, Fe, and Zn, uptake continued throughout exponential growth. Elements were released from the cells immediately following initial uptake. For Mn, egression continued to t2, with release of 36% of total accumulated. Secondary uptake followed immediately and continued through stage V. Magnesium egression continued to t1 with release of 33% accumulated. Secondary uptake began by t5 (stage IV) and continued slowly through sporulation. Calcium egression ceased by t4 with release of 25% total accumulated. Secondary uptake began by t6 (stage V) and continued until depleted. Zinc egression stopped by t5 with release of 34% accumulated with some secondary uptake by stage V. Iron egression terminated at t4 with release of 59% of total accumulated. This was followed by secondary uptake after t12 (stage VI).

Pathway of glucose catabolism in Caulobacter crescentus.

Glucose when present as a sole organic carbon source in a mineral salts medium is dissimilated by Caulobacter crescentus ATCC 15252 (strain CB-2) by the Entner-Doudoroff pathway throughout the culture cycle (exponential, transition, and stationary phase). Most of the available glucose that is present at the onset of exponential growth is assimilated by the cells during the transition phase or the period associated with stalk cell development. Swarmer cell development is minimized during this phase. During this same period the pH drops from 6.1 to 4.9 as a result of an abundant excretion of acetic acid. Simultaneously, poly-beta-hydroxybutyrate accumulates within the cells at an accelerated rate. An NADP-dependent glyceraldehyde-3-phosphate dehydrogenase is also present throughout the culture cycle which subsumes the presence of the subsequent enzymes of the Embden-Meyerhof-Parnas pathway in pyruvate formation. An operative tricarboxylic acid cycle is associated with cells throughout the culture cycle.