Diversity of microbial communities correlated to physiochemical parameters in a digestion basin of a zero-discharge mariculture system

Bacterial community structure and physiochemical parameters were examined in a sedimentation basin of a zero-discharge mariculture system. The system consisted of an intensively stocked fish basin from which water was recirculated through two separate treatment loops. Surface water from the basin was pumped over a trickling filter in one loop while bottom-water was recirculated through a sedimentation basin followed by a fluidized bed reactor in the other. Ammonia oxidation to nitrate in the trickling filter and organic matter digestion together with nitrate reduction in the sedimentation basin and fluidized bed reactor, allowed zero-discharge operation of the system. Relatively high concentrations of oxygen, nitrate, sulphate and organic matter detected simultaneously in the digestion basin suggested the potential for a wide range of microbially-mediated transformation processes. In this study, physiochemical parameters were correlated to bacterial diversity and distribution in horizontal and vertical profiles within this basin in an effort to obtain a basic understanding of the chemical and microbial processes in this system. Chemical activity and microbial diversity, the latter measured by denaturing gradient gel electrophoresis (DGGE) analysis of polymerase chain reaction (PCR) amplified 16S rDNA fragments, were higher in the sludge layer than in the overlying aqueous layer of the basin. Chemical parameters in sludge samples close to the basin inlet suggested enhanced microbial activity relative to other sampling areas with evidence of both nitrate and sulphate reduction. Four of the nine DGGE bands identified in this zone were affiliated with the Bacteroidetes phylum. Detected sequences closely related to sequences of organisms involved in the sulphur cycle included Desulfovibrio, Dethiosulfovibrio and apparent sulphur oxidizers from the gamma-proteobacteria. In addition, a number of sequences from the beta and alpha-proteobacteria were identified.     

TGF-beta1 increases microbial clearance but worsens lung injury during Escherichia coli pneumonia in rats

We investigated the effects of either intravenous (IV) or intrabronchial (IB) treatment with transforming growth factor beta1 (TGF-beta1) during bacterial pneumonia in rats. Immediately following IB Escherichia coli inoculation (T0), animals (n=270) were randomized to receive a single treatment with human recombinant TGF-beta1 either via IV or IB, or via both IV and IB routes, or to receive placebo (human serum albumin, HSA) only. Blood and lung analysis was done at 6 and 168 h after E. coli inoculation. Other animals (n=40) were administered IV TGF-beta1 or HSA at T0 and 6, 12 and 24 h after E. coli inoculation to investigate the effects of multiple treatments also on survival rates alone. All animals received ceftriaxone daily. Route of administration did not influence TGF-beta1 (p=ns for the effect of TGF-beta1 comparing IV vs IB routes) and we averaged over this variable in analysis. The relative risk of death (mean +/- sem) was not altered by either single treatments administered at T0 (-0.18 +/- 0.25, p=0.47) or multiple treatments (0.40 +/- 0.50, p=0.66) of TGF-beta1. Single treatment with TGF-beta1 first decreased and then increased vascular leukocytes at 6 and 168 h, respectively, but increased alveolar leukocytes at both time points (p=0.02 comparing the differing effects of TGF-beta1 on vascular and alveolar leukocytes at 6 and 168 h). Although TGF-beta1 decreased blood and lung bacteria counts at 6 and 168 h, it also increased serum tumor necrosis factor levels and lung injury scores at these time points (p<0.05 for the effects of TGF-beta1 on each parameter at 6 and 168 h together). Thus, while increases in lung leukocyte recruitment with TGF-beta1 were associated with improved microbial clearance in this rat model of pneumonia, worsened lung injury may have negated these beneficial host defense effects, and overall survival was not significantly improved. Despite these harmful effects, additional studies may be warranted to better define the influence of exogenous TGF-beta1 on host defense during acute bacterial infections.     

Structure-activity relations of the dark-colour-inducing neurohormone of locusts

The dark-colour-inducing effect of several peptides in comparison to that of the dark-colour-inducing neurohormone (DCIN, [His(7)]-corazonin) of locusts was investigated by a bioassay based on nymphs of a DCIN-deficient albino mutant of Locusta migratoria. The study was aimed at elucidating the active part of the DCIN and to explore the contribution of its amino acids to the activity. Graded doses of all peptides were injected in oil. [Arg(7)]-corazonin and DCIN were equally effective. Certain arthropod neuropeptides having the -SXGW- partial sequence (a part of the DCIN and of [Arg(7)]-corazonin; X=His and X=Arg, respectively) yielded the following findings: Scg-AKH-II (adipokinetic hormone II of Schistocerca gregaria X=Thr), Grb-AKH ( adipokinetic hormone of Gryllus bimaculatus X=Thr) and RPCH (red pigment concentrating hormone of crustaceans X=Pro) evoked a moderate darkening response, but Lom-AKH-II (adipokinetic hormone II of L. migratoria X=Ala) was ineffective. Step by step shortening of the sequence of the DCIN at the N-terminal, from pGlu-3-11DCIN to pGlu-9-11DCIN, resulted in a decreasing activity, but even pGlu-9-11DCIN induced a weak response with high doses. Shortening of the DCIN from the C-terminal revealed a moderate activity of 1-7DCIN-NH(2) and a weak activity of 1-5DCIN-NH(2). An octadecapeptide which induces dark colour in moth larvae, having the pentamer FTPRL-NH(2) at its C-terminal, evoked no darkening in the albino locusts. We conclude that although the -SXGW- partial sequence has some role in induction of darkening, for obtaining maximal effect the whole sequence of the DCIN (or of [Arg(7)]-corazonin) is necessary.     

Recombinant Fv immunotoxins and Fv fragments as novel agents for cancer therapy and diagnosis

Recombinant immunotoxins are new agents being developed for cancer therapy. They are composed of Fv fragments of antibodies that bind to cancer cells fused to a truncated form of a very potent bacterial toxin. The antibody moiety directs the toxin to cancer cells, which are killed, while normal cells are not recognized and thus survive. The excellent preclinical results in vitro and in vivo have led to the initiation of several clinical trials.     

A simple Markov model for the assessment of host patch quality by foraging parasitoids

Insect parasitoids search for their hosts using a method that may be broken into three parts. First, they locate plants which may harbor their hosts, then they assess the quality of these plants to decide whether to search them further for hosts and, finally, if they decide to accept a plant for further search, they exploit the plant by searching for hosts and attacking them when they are found. We study the way that parasitoids assess plant quality by developing a mathematical model based on behavioral observations of foraging parasitoids that attack aphids which infest crucifers. Assessment of plants is based on the concentration of cues produced by hosts that inhabit them. Parasitoids are more likely to exploit plants on which more host cues are detected, and the willingness of a parasitoid to exploit a given plant depends on the quality of other plants that have been visited recently. Plants whose quality exceeds a certain threshold will be accepted for exploitation. The threshold for plant acceptance will change with the experience of the parasitoid, increasing when plants heavily infested with hosts are encountered, decreasing when uninfested plants are encountered. We analyze several rules that might describe how the acceptance threshold changes with parasitoid experience, and for each rule we show how the number of parasitoids willing to accept plants with various levels of infestation depends on the number of plants with various levels of infestation. We then consider different rules for exploitation of hosts on plants and find how the proportion of hosts attacked depends on host density. Received: 21 April 1998 / Accepted: 8 May 1998     

Redundant and Distinct Functions for Dynamin-1 and Dynamin-2 Isoforms

A role for dynamin in clathrin-mediated endocytosis is now well established. However, mammals express three closely related, tissue-specific dynamin isoforms, each with multiple splice variants. Thus, an important question is whether these isoforms and splice variants function in vesicle formation from distinct intracellular organelles. There are conflicting data as to a role for dynamin-2 in vesicle budding from the TGN. To resolve this issue, we compared the effects of overexpression of dominant-negative mutants of dynamin-1 (the neuronal isoform) and dynamin-2 (the ubiquitously expressed isoform) on endocytic and biosynthetic membrane trafficking in HeLa cells and polarized MDCK cells. Both dyn1(K44A) and dyn2(K44A) were potent inhibitors of receptor-mediated endocytosis; however neither mutant directly affected other membrane trafficking events, including transport mediated by four distinct classes of vesicles budding from the TGN. Dyn2(K44A) more potently inhibited receptor-mediated endocytosis than dyn1(K44A) in HeLa cells and at the basolateral surface of MDCK cells. In contrast, dyn1(K44A) more potently inhibited endocytosis at the apical surface of MDCK cells. The two dynamin isoforms have redundant functions in endocytic vesicle formation, but can be targeted to and function differentially at subdomains of the plasma membrane.     

Working with Jewish ultra-orthodox patients: Guidelines for a culturally sensitive therapy

The epistemological gap between the medical reality of mental health practitioners and the sacred reality of their Jewish ultra-orthodox patients poses a major challenge for therapy. Based on our work with psychiatric patients from the ultraorthodox community of northern Jerusalem, we propose a set of guidelines to cope with this challenge. Basically, we seek to incorporate religiously congruent elements, composed of metaphoric images, narratives and actions, into the wide range of our secular treatment modalities in order to respond to the patient's suffering, often expressed through distinctively religious idioms of distress. This endeavor calls for a temporary suspension of disbelief on both sides.The guidelines presented include three sets of factors which appear pertinent to working with ultra-orthodox patients. The first set is contextual in nature, dealing with the image of the clinic and its physical setting; the second discusses the necessary role requisites of the therapists; and the third one, accorded a central importance, deals on various levels with the therapeutic interventions administered in terms of form and content. Several case vignettes are presented to illustrate three classes of religiously informed interventions: healing rituals, dream interpretation, and the use of culturally congruent metaphors and stories. In the concluding part we discuss ethical and instrumental issues that the proposed therapeutic guidelines may raise.     

The relationship between short-term antibiotic treatments and fatigue in healthy individuals

Antibiotic treatment tends sometimes to result in sensations of fatigue and decreased physical performance. The effects of antibiotics were therefore studied in 50 healthy, male trainees, aged 18–25 years, assigned in a random, double-blind fashion to one of the following treatments: tetracycline, ampicillin, trimethoprim/sulphamethoxazole, placebo I and placebo II. Duration of treatment was five times the half-life of each agent and the placebo was matched accordingly. Muscle enzyme activity (serum glutamine oxaloacetate transaminase, lactate dehydrogenase, creatine phosphokinase), maximal aerobic capacity ( O_2max), muscle strength (MS), and rating of subjective sensation of fatigue were assessed prior to and upon conclusion of treatment. Compared to pretreatment values, plasma enzymes activity was elevated in all five groups (P<0.005). No differences in O_2max or in MS were found among the subjects treated with either one of the antibiotics or those given a placebo. A significant difference in O_2max was found between the groups treated for 1 day (antibiotic and placebo) and the groups treated for 3 days (antibiotic and placebo) (P<0.0001). The rating of subjective sensation was not affected by any of the agents. We concluded that in healthy individuals, a short-term antibiotic treatment had no deleterious effect on aerobic capacity or on muscle strength and was not associated with subjective side effects. The time interval between the two maximal tests could, however, have affected the aerobic capacity. Physiological disturbances associated with a sensation of fatigue following a longer period of antibiotics cannot be excluded.     

Type II diabetes mellitus,congestive heart failure,and zinc metabolism

Zinc status was assessed in patients with type II diabetes mellitus and congestive heart failure (CHF). Three groups of patients were enrolled into the study: Group 1: 15 patients with type II diabetes mellitus and CHF; Group 2: 20 patients with isolated type II diabetes mellitus; and Group 3: nine patients with isolated CHF. Twenty-four-hour urine was measured for creatinine, protein, and zinc, and blood was drawn for creatinine, proteins, liver enzymes, hemoglobin A₁c, and zinc. Insulin treatment and hemoglobin A₁c were comparable in the diabetic patients of groups 1 and 2, but group 1 was also treated with captopril and diuretics like the CHF patients of group 3. Plasma zinc levels were statistically similar in all three groups, but urinary zinc excretion (μmol/24 h) and urinary zinc: creatinine (μmol/mmol) ratio were significantly higher in the type II diabetics and CHF group (27.2±1.5; 1.69±0.6, respectively) compared to the diabetic patients alone (19.4±0.76; 0.97±0.3, respectively) and the CHF patients (9.7±0.3; 0.62±0.3, respectively). Patients with type II diabetes mellitus and CHF were treated with higher doses of captopril than the CHF patients (56.25±24 mg vs 18.8±11 mgP<0.05). Thus, patients with type II diabetes mellitus and CHF excrete larger amounts of zinc, which may eventually lead to zinc deficiency.     

Ubiquinone reduction and proton uptake by chromatophores of Rhodopseudomonas sphaeroides R-26. Periodicity of two in consecutive light flashes

Chromatophores of Rhodopseudomonas sphaeroides strain R-26 were subjected to a series of brief flashes of light in the presence of diaminodurene as an electron donor. Odd-numbered flashes induced the reduction of ubiquinone to the anionic semiquinone, as indicated by absorbance changes near 450 nm. This reaction was not attended by proton binding. Even-numbered flashes caused disappearance of the semiquinone, presumably by conversion to the fully reduced form. This reaction was attended by proton uptake.