Structural inhibition of the colicin D tRNase by the tRNA-mimicking immunity protein

Colicins are toxins secreted by Escherichia coli in order to kill their competitors. Colicin D is a 75 kDa protein that consists of a translocation domain, a receptor-binding domain and a cytotoxic domain, which specifically cleaves the anticodon loop of all four tRNA(Arg) isoacceptors, thereby inactivating protein synthesis and leading to cell death. Here we report the 2.0 A resolution crystal structure of the complex between the toxic domain and its immunity protein ImmD. Neither component shows structural homology to known RNases or their inhibitors. In contrast to other characterized colicin nuclease-Imm complexes, the colicin D active site pocket is completely blocked by ImmD, which, by bringing a negatively charged cluster in opposition to a positively charged cluster on the surface of colicin D, appears to mimic the tRNA substrate backbone. Site-directed mutations affecting either the catalytic domain or the ImmD protein have led to the identification of the residues vital for catalytic activity and for the tight colicin D/ImmD interaction that inhibits colicin D toxicity and tRNase catalytic activity.     

Laboratory and field evaluations of transgenic soybean exhibiting high-dose expression of a synthetic Bacillus thuringiensis cry1A gene for control of Lepidoptera

Transgenic lines of soybean, Glycine max (L.) Merrill, expressing a synthetic cry1A gene (tic107) from Bacillus thuringiensis (Bt), were evaluated in screenhouse and conventional field trials for efficacy against lepidopteran pests. In screenhouse trials, Bt soybean and negative checks (isogenic segregants and parental lines) were evaluated against Anticarsia gemmatalis Hübner and Pseudoplusia includens (Walker) in the United States and against A. gemmatalis, Epinotia aporema (Walsingham), Rachiplusia nu (Guenée), and Spilosoma virginica (F.) in Argentina. Bt soybean exhibited virtually complete efficacy against each of these pests, whereas negative checks suffered significant damage. Bt soybean and negative checks also were evaluated in conventional trials against native populations of A. gemmatalis and P. includens in the southeastern United States. Each of these insects caused significant damage to negative checks in one or more locations, whereas Bt soybean exhibited virtually complete efficacy against these pests. In the laboratory, lyophilized leaf tissues from Bt soybean incorporated in artificial diet at a concentration representing a 25-fold dilution of fresh tissue caused complete mortality of A. gemmatalis and near complete mortality of P. includens neonates after 11 d, whereas mortality on negative checks did not exceed 10% for either insect. Average TIC107 expression approached or exceeded 50 microg/g fresh weight at V3 stage of growth and 200 microg/g by R6 stage of growth. These results demonstrate that expression of TIC107 in soybean can not only achieve highly efficacious control of several lepidopterans under field conditions but also provide a high dose for effective insect resistance management.     

Cataract surgery and postoperative complications in diabetic patients

Diabetes mellitus influences the function and morphology of the eye lens. The cataract is the second most common complication of diabetes mellitus on the eye. A hundred patients with cataract were examined in the prospective study. The patients were divided into two groups. The first group consisted of 50 patients with cataract who had not suffered from a system or local disease. The second group consisted of 50 patients with cataract and diabetes mellitus that had lasted for at least five years. In both groups the patients underwent identical cataract extra capsular extraction with intraocular PMMA (polymethylmethacrylate) lens implantation in camera posterior. The objective of this study was to compare the two groups of patients in order to find out the most common intraoperative or postoperative complications in diabetics. The most common postoperative complications in patients suffering from diabetes were inflammatory reactions and bleeding: postoperative keratopathy, uveitis anterior serous and uveitis anterior fibrinous with posterior sinechia and opacity of the posterior lens capsule as results. Postoperative visual acuity was worse in the patients in group II on the seventh day and six months after operation. It was diabetic retinopathy and its progression that caused deterioration of visual acuity. Diabetic retinopathy and its progression, as well as maculopathy were found only in patients who were not treated with photocoagulation before the operation.     

Visual loss as initial presentation of chronic myelogenous leukemia

A previously healthy 17-year old girl presented with sudden visual loss in both eyes. Visual acuity on the right eye was 0.3 and on the left eye 0.1. Fundoscopic examination showed bilateral optic disc edema, retinal venous tortuousity and dilatation, retinal blot and flame-shaped hemorrhages, Roth spots and on the left eye dark blot preretinal hemorrhage covering the fovea. Laboratory evaluation showed white blood cell count of 455 x 10(9) L. Bone marrow biopsy confirmed the diagnosis of chronic myelogenous leukemia. Chemotherapy was initiated and led to the improvement of visual acuity. Fundus changes had resolved except for the preretinal hemorrhage on left eye which decreased in size. Preretinal hemorrhage in fovea caused maculopathy on the left eye. Three months after admisson visual acuity was 1.0 on the right eye and 0.3 on the left eye. Leukemia should always be included in the differential diagnosis of optic disc edema and retinal hemorrhages.     

Paralytic strabismus as a manifestation of lyme borreliosis

Lyme disease is a multi-system organ disorder caused by Borrelia burgdorferi. Although ocular manifestations have been reported, these remain a rare feature of the disease. This report shows a 49-years old patient that has been bitten by a tick and as consequence of which developed symptoms of the Lyme disease. In 1998 the patient was hospitalized in our Eye Clinic due to operating treatment of the paralytic strabismus (abductal nerve paralysis), as a rare feature of the Lyme disease. Postoperative squint angle was significantly reduced, but without any temporal movement. Diplopia was still present, though slightly reduced with the use of prism eyeglasses. The improvement of the quality of life was achieved, as well as the patient's satisfaction.     

Female urethral dilatation (bougierung): a case report

Background

Primary bladder neck obstruction is a rare clinical entity, reported to be responsible for 2.7–8% of lower urinary tract symptoms. It can lead to various urinary storage and voiding symptoms. The mainstay of treatment of female urethral strictures is urethral dilatation. Despite the long history of this method, it is unclear how far the female urethra should be dilated in correlation with residual urine volume.

Case presentation

A 79-year-old Caucasian woman presented to our institute with urgency (12–15 times/day), nocturia (3 times/night), and reoccurring urinary tract infections. A physical examination revealed no anatomical malformation in her genital organs, 150 mL post-void urine retention, and a significant narrowing in the mid-segment of the urethra (4 mm). After informed consent, our patient underwent urethral dilatation ranging from Ch9 (3 mm) to Ch39 (13 mm), and reported no symptoms at the 4-week follow-up, with no post-void residual urine.

Conclusions

The relatively low (around 50%) success rate of urethral dilatation might be improved by the utilization of wider dilatators, and the relaxation of the pubourethral ligament, achieved by a gentle downward saggital push during the intervention, although long-term studies with a large number of participants are necessary to prove our hypothesis.

     

Genetic evidence for an essential role of brassinosteroids in plant development

Brassinosteroids which show high structural similarity to animal steroid hormones elicit a variety of growth responses when exogeneously applied to plant tissues. Thus far however, the function of endogeneous brassinosteroids in higher plants has been unclear. This paper describes three extremely dwarfed Arabidopsis thaliana mutants, cbb1 (dwf1-6), cbb2 and cbb3, which are impared in cell elongation controlled by brassinosteroids. While cbb1 (dwf1-6) and cbb3 can be phenotypically normalized to wild-type by feeding with brassinosteroids indicating deficiencies of brassinosteroid biosynthesis, cbb2 is brassinosteroid-insensitive and defines a function required for further metabolic conversion necessary for biological activity or for perception/signal transduction of these growth-regulating plant steroid hormones. Expression of the meri5 and TCH4 genes is low in all three cbb mutants and can be restored to wild-type levels by brassinosteroid treatment in the cbb1 (dwf1-6) and cbb3 mutants but are unaffected in the cbb2 mutant. These data indicate that brassinosteroids are essential for proper plant development and play an important role in the control of cell elongation.     

The human homologue of the Drosophila melanogaster flightless-I gene (flil) maps within the Smith-Magenis microdeletion critical region in 17p11.2.

The Smith-Magenis syndrome (SMS) appears to be a contiguous-gene-deletion syndrome associated with a proximal deletion of the short arm of chromosome 17 in band p11.2. The spectrum of clinical findings includes short stature, brachydactyly, developmental delay, dysmorphic features, sleep disturbances, and behavioral problems. The complex phenotypic features suggest deletion of several contiguous genes. However, to date, no protein-encoding gene has been mapped to the SMS critical region. Recently, the Drosophila melanogaster flightless-I gene, fliI, and the homologous human cDNA have been isolated. Mutations in fliI result in loss of flight ability and, when severe, cause lethality due to incomplete cellularization with subsequent abnormal gastrulation. Here, we demonstrate that the human homologue (FLI) maps within the SMS critical region. Genomic cosmids were used as probes for FISH, which localized this gene to the 17p11.2 region. Somatic-cell hybrid-panel mapping further localized this gene to the SMS critical region. Southern blot analysis of somatic-cell hybrids and/or FISH analysis of lymphoblastoid cell lines from 12 SMS patients demonstrates the deletion of one copy of FLI in all SMS patients analyzed.     

Validating the use of a commercial enzyme immunoassay to measure oxytocin in unextracted urine and saliva of the western lowland gorilla (<Emphasis Type="Italic">Gorilla gorilla gorilla</Emphasis>)

The neuroendocrine hormone oxytocin, which is an important physiological driver of social behavior and bonding, is increasingly being measured in conjunction with behavior to better understand primate sociality. To date no data are available on oxytocin concentrations within the genus Gorilla; however, as a result of their close genetic relatedness to humans, and tolerance-based social system, Gorilla represents an important group of study. The purpose of this study was to validate the measurement of urinary and salivary oxytocin in western lowland gorillas (Gorilla gorilla gorilla) to help facilitate future study of the interaction between oxytocin and behavior within the subspecies. The primary validation procedure was an intranasal challenge. Elevated oxytocin concentrations were observed in saliva samples taken 15–120 min post challenge. Urine levels remained within baseline range approximately 30 and 90 min following the challenge; however, elevated levels were observed 24 h post challenge. No diurnal variation was found in salivary samples taken at regular intervals throughout the day; however, morning urine samples had higher concentrations than afternoon samples. In addition, samples were collected opportunistically following three social events: play, breeding, and the death of a conspecific. Following the play bouts, salivary oxytocin was almost three times greater than baseline. Salivary oxytocin was also significantly higher 15 min post breeding compared to match-control samples. Following the death of a conspecific, the group mate’s urinary oxytocin concentrations decreased by half compared to a baseline period when the group was intact. This study provides a biological validation of the measurement of urinary and salivary oxytocin in western lowland gorillas. These results suggest that urinary oxytocin measurements are suitable for establishing baseline levels, as they represent the build up of the previous day’s concentrations, and salivary oxytocin measurements are suitable for assessing changes following specific events.