Electron microscopy of the uredinial and telial stages of the rust fungus, Puccinia imperatae.

The purpose of this work was to assess the morphology and ontogeny of Puccinia imperatae urediniospores and teliospores growing on its host, Imperata cylindrica, for the first time using scanning (SEM) and transmission (TEM) electron microscopy. The first evidence of uredinial development is the aggregation of hyphae in host intercellular spaces under the epidermis to form an uredinial initial. Uredinial primordia become evident as compact masses of fungal hyphae. The mycelia are dikaryotic and originated from dikaryotic urediniospores, which infect a new host. Dikaryotic sporogenous cells begin to form from dikaryotic mycelium as the uredinium develops further. The fundamental cell in the urediniospore and teliospore formation is the sporogenous cell. The teliospores with their persistent pedicels arise from dense dikaryotic sporogenous tissue, which later becomes highly vacuolated. The sporogenous cell forms a spore bud, which later divides into a pedicel and teliospore mother cell with two nuclei that produce the mature teliospore. SEM examination revealed that the urediniospores are echinulate bearing conical spines on their surfaces, sometimes curving near their tips, and the echinulate ornaments are distributed over the entire urediniospore surface. SEM examination also indicated that the teliospore surface shows rugose ornamentations. This investigation proved that the morphology of the uredinia of different Puccinia species is not related to the host species, but to the rust species. The possibility of using this fungus as a biological control agent for the noxious weed, Imperata cylindrica, was also discussed.

Biological and molecular characterization of fEg-Eco19, a lytic bacteriophage active against an antibiotic-resistant clinical Escherichia coli isolate.

Characterization of bacteriophages facilitates better understanding of their biology, host specificity, genomic diversity, and adaptation to their bacterial hosts. This, in turn, is important for the exploitation of phages for therapeutic purposes, as the use of uncharacterized phages may lead to treatment failure. The present study describes the isolation and characterization of a bacteriophage effective against the important clinical pathogen Escherichia coli, which shows increasing accumulation of antibiotic resistance. Phage fEg-Eco19, which is specific for a clinical E. coli strain, was isolated from an Egyptian sewage sample. Phage fEg-Eco19 formed clear, sharp-edged, round plaques. Electron microscopy showed that the isolated phage is tailed and therefore belongs to the order Caudovirales, and morphologically, it resembles siphoviruses. The diameter of the icosahedral head of fEg-Eco19 is 68 ± 2 nm, and the non-contractile tail length and diameter are 118 ± 0.2 and 13 ± 0.6 nm, respectively. The host range of the phage was found to be narrow, as it infected only two out of 137 clinical E. coli strains tested. The phage genome is 45,805 bp in length with a GC content of 50.3% and contains 76 predicted genes. Comparison of predicted and experimental restriction digestion patterns allowed rough mapping of the physical ends of the phage genome, which was confirmed using the PhageTerm tool. Annotation of the predicted genes revealed gene products belonging to several functional groups, including regulatory proteins, DNA packaging and phage structural proteins, host lysis proteins, and proteins involved in DNA/RNA metabolism and replication.

Identification and Functional Analysis of Temperate Siphoviridae Bacteriophages of Acinetobacter baumannii.

Acinetobacter baumannii is an opportunistic pathogen that presents a serious clinical challenge due to its increasing resistance to all available antibiotics. Phage therapy has been introduced recently to treat antibiotic-incurable A. baumannii infections. In search for new A. baumannii specific bacteriophages, 20 clinical A. baumannii strains were used in two pools in an attempt to enrich phages from sewage. The enrichment resulted in induction of resident prophage(s) and three temperate bacteriophages, named vB_AbaS_fEg-Aba01, vB_AbaS_fLi-Aba02 and vB_AbaS_fLi-Aba03, all able to infect only one strain (#6597) of the 20 clinical strains, were isolated. Morphological characteristics obtained by transmission electron microscopy together with the genomic information revealed that the phages belong to the family Siphoviridae. The ca. 35 kb genomic sequences of the phages were >99% identical to each other. The linear ds DNA genomes of the phages contained 10 nt cohesive end termini, 52-54 predicted genes, an attP site and one tRNA gene each. A database search revealed an >99% identical prophage in the genome of A.baumannii strain AbPK1 (acc. no. CP024576.1). Over 99% identical prophages were also identified from two of the original 20 clinical strains (#5707 and #5920) and both were shown to be spontaneously inducible, thus very likely being the origins of the isolated phages. The phage vB_AbaS_fEg-Aba01 was also able to lysogenize the susceptible strain #6597 demonstrating that it was fully functional. The phages showed a very narrow host range infecting only two A.baumannii strains. In conclusion, we have isolated and characterized three novel temperate Siphoviridae phages that infect A.baumannii.

Outbreak of Middle East Respiratory Syndrome at Tertiary Care Hospital, Jeddah, Saudi Arabia, 2014.

During March-May 2014, a Middle East respiratory syndrome (MERS) outbreak occurred in Jeddah, Saudi Arabia, that included many persons who worked or received medical treatment at King Fahd General Hospital. We investigated 78 persons who had laboratory-confirmed MERS during March 2-May 10 and documented contact at this hospital. The 78 persons with MERS comprised 53 patients, 16 healthcare workers, and 9 visitors. Among the 53 patients, the most probable sites of acquisition were the emergency department (22 patients), inpatient areas (17), dialysis unit (11), and outpatient areas (3). Infection control deficiencies included limited separation of suspected MERS patients, patient crowding, and inconsistent use of infection control precautions; aggressive improvements in these deficiencies preceded a decline in cases. MERS coronavirus transmission probably was multifocal, occurring in multiple hospital settings. Continued vigilance and strict application of infection control precautions are necessary to prevent future MERS outbreaks.

Intracellular tubulo-reticular structures of peripheral blood mononuclear cells as an ultra-structural marker of disease activity in systemic lupus erythematosus: a pilot study.

OBJECTIVE: Under physiological stress, the membranes of organelles undergo conformational change to tubulo-reticular structures (TRS) for gaining survival advantage. We aim to explore whether TRS formation in the peripheral blood mononuclear cells (PBMCs) of patients with systemic lupus erythematosus (SLE) correlates with more active disease where physiological stress prevails. METHODS: To mimic the intracellular impact of interferon-alpha (IFN-α) on lymphocytes, human B-lymphocyte cell line was stimulated by recombinant IFN-α in concentrations of 100, 1000 and 10 000 IU/mL for 72 h. TRS within the lymphocytes was then quantified by transmission electron microscopy (TEM). Upon confirming TRS formation under IFN-α influence, PBMCs of lupus patients were isolated, fixed and quantified for TRS under TEM. The frequency of TRS in lupus PBMCs was compared with that of healthy controls and correlated with the clinical SLE disease activity index (SLEDAI). RESULTS: After 72 h, an increase in TRS frequency was observed in a dose-response fashion when the human B-lymphocyte cell line was stimulated by increasing concentrations of IFN-α. In lupus patients, their PBMCs had a significantly higher TRS frequency than healthy controls (P = 0.037). The frequency of TRS was positively associated with the SLEDAI (Spearman ρ = 0.632, P = 0.012), which remained statistically significant after adjustment for daily prednisolone dose (Pearson r = 0.747, P = 0.002). CONCLUSIONS: While the clinical significance of TRS formation in lupus PBMCs deserves further investigation, these preliminary findings suggest a significant relationship between the disease severity of SLE and intracellular physiological stress. These results underscore the potential of TRS in PBMCs as an ultra-structural disease activity biomarker of SLE.

Occurrence of Puccinia isiacae on Phragmites australis in Saudi Arabia and its possibility as a biological control agent.

During the summer of 2002, symptoms of rust disease were observed for the first time on Phragmites australis in Saudi Arabia. Light brown lesions of regular shape indicating uredinia of Puccinia isiacae appeared on the leaves. The morphology and characteristics of the fungus were described in detail with both light and scanning electron microscopy. The possibility of using this fungus as a biological control agent was also discussed.

Ultrastructure of intercellular hypha and haustorium of the rust fungus, Uromyces euphorbiae.

The ultrastructure of intercellular hyphae and dikaryotic haustoria of Uromyces euphorbiae, and the host response to haustorial invasion was investigated. The intercellular hyphae share common characteristics with those of other uredinial stages of rust fungi. Three types of septa were recognized inside the intercellular hypha. This study showed that the extrahaustorial membrane was possibly formed before the development of the haustorium. The periodic acid-thiocharbohydrazide-silver proteinate technique showed that the haustorial mother cell wall at the penetration site, and the haustorial wall contained more carbohydrates than other fungal structures. In addition, the neckband, present around the haustorial neck, contains different material from those of the rest of the haustorial neck wall. The close associations of host organelles, such as the nucleus, chloroplasts, mitochondria, endoplasmic reticulum and microtubules, with the haustorium, is described.

Medical informatics on the Internet: creating the sci.med. informatics newsgroup.

A Usenet newsgroup, sci.med.informatics, has been created to serve as an international electronic forum for discussion of issues related to medical informatics. The creation process follows a set of administrative rules set out by the Usenet administration on the Internet and consists of five steps: 1) informal discussion, 2) request for formal discussion, 3) formal discussion, 4) voting, and 5) posting of results. The newsgroup can be accessed using any news reader via the Internet.

LabTalk/2: a middleware approach to HIS integration.

LabTalk/2 is an intelligent interface between a legacy order-entry system and a legacy laboratory information system. Unlike other interfaces, LabTalk/2 does more than just transform data from one format to another; it transforms the manner in which data is processed. Utilizing the "middleware" concept, it sits independently between the two systems, decoupling their maintenance needs. Implementation has been successful.

Histochemistry of normal and diseased human lymph nodes.

Gomori's metal precipitate technique was used to demonstrate the phosphatase activity of the human cervical lymph node in health and disease, using four different phosphate esters (sodium beta-glycerophosphate and adenosine triphosphate at pH 9, riboflavin 5'-phosphate at pH 9.2 and 5'-monophosphoric acid at pH 8.3). In fetal lymph nodes, using 5'-monophosphoric acid, an outstanding positive activity was noticed in the lymphatic follicles. With the other three substrates there was either no nodular reaction or just a narrow rim of positive activity around the follicles, the internodular tissue being negative with all four substrates used. With chronic non-specific lymphadenitis the enzyme hydrolysing the three substrates (beta-glycerophosphate, riboflavin 5'-phosphate and adenosine triphosphate) began to make their appearance. It seems that with lymphadenitis, a qualitative change of the phosphatase activity takes place. A special characteristic pattern of phosphatase activity has been described in both 'early' and 'caseating' tuberculous lymphadenitis. In malignant lymphomas it was noticed that no activity was encountered with any of the four substrates in reticulum cell sarcoma. However, in lymphosarcoma a positive activity was obtained when either beta-glycerophosphate or adenosine triphosphate substrates was used, to the extent that one can depend upon this characteristic phosphatase activity in differentiating between reticulum cell sarcoma and lymphosarcoma. However, no enzymatic activity was obtained when the other two phosphate esters were used.

Alkaline phosphatase in the thymus.

(1) Fetal thymuses, organs from patients who died from diseases that are not clinically known to be associated with concomitant lymphoid tissue involvement, as well as thymuses from patients dying from diseases which effect the lymphatic complex of the body, one way or another, have been investigated for their alkaline phosphatase activity, using Gomori technique and applying four different phosphate esters as substrates. (2) Three substrates (beta-glycerophophate, riboflavin 5-phosphate and adenosine triphosphate) showed essentially the same pattern of activity in which the cortex and Hassall's corpuscles were reactive, while the medulla was negative. A reversal of this pattern was demonstrated with 5-monophosphoric acid. (3) Before the age of 32-36 weeks of intra-uterine life there is no alkaline phosphatase activity in the thymus; therafter, the enzyme begins to make its first appearance. (4) There is a definite increase in the intensity of the reaction with advance of intra-uterine life. This increase in phosphatase content is continued postnatally, to reach its maximum at about the age of 10 years: after that, the enzyme activity gradually subsides. (5) There is a tremendous augmentation of phosphatase activity in the case of disease which are known to affect the lymphoid complex. (6) The phosphatase activity of the thymus has been discussed in relation to the prevailing concepts about the function of the thymus, with special emphasis on a possible association with 'lymphocyte-stimulating factor' production and/or secretion.

Alkaline phosphatase activity in the human tonsils and its relation to tonsillar diseases.

Alkaline phosphatase activity was examined in the human tonsils in fetal life and after repeated attacks of acute tonsillitis and in quinsy. Gomori's metal precipitate technique was used to demonstrate the phosphatase activity using four different substrates: sodium beta-glycerophosphate and adenosine triphosphate at pH 9, riboflavin 5-phosphate at pH 9.2 and 5-monophosphoric acid at pH 8.3. (2) The phosphatase activity differs somewhat according to the phosphate ester used as a substrate illustrating an example of 'substrate specificity'. (3) Alkaline phosphatase activity was increased in the case of both acute and chronic inflammation. This increase has been discussed in relation to such phenomena as transformation of lymphocytes into macrophages and antibody formation.

Cholinesterase activity in some human lymphatic organs.

(1) Cholinesterase activity was investigated in some human lymphatic organs (palatine tonsil, 'normal' spleen, 'bilharzial' spleen, thymus, lymph node and appendix) using GOMORI'S modification of KOELLE and FRIEDENWALD'S thiocholine iodide method, hydrolyzing acetylthiocholine iodide and butyrylthiocholine iodide. (a) Acetyl- and butyrylcholinesterases seemed to be different enzymes; but when they have the same pattern of activity, the latter generally offers a weaker reaction. (b) All the lymphatic follicles of the tonsil, those found in the cortex of the cervical lymph nodes as well as those present in the appendix, were stainable with both acetyl- and butyrylcholinesterase. (c) Acetylcholinesterase activity was not demonstrated in the Malpighian bodies of the 'normal' spleen, but the reaction was strongly present in the blood vessels (including the central arterioles) as well as in the capsule and the different components of the trabecular system. (d) In 'bilharzial' splenomegaly a relatively strong activity started to appear in the Malpighian corpuscles, manifested as a brownish precipitate in their centres. Also some patchy positive areas began to make their appearance in the tissue of the red pulp and had a particular arrangement around the Malpighian corpuscules, in such a way as to 'wall them off' from the tissue of the red pulp. (e) In the thymus no acetylcholinesterase activity was encountered, except in Hassal's corpuscles and in the trabeculae between the thymic lobules. (2) The data obtained in this work were discussed in relation to previous works in other laboratories and it seems that a species difference exists. (3) Cholinesterases may be present in the lymphatic tissue in order to get rid of some potentially toxic esters resulting from the necrobiotic phenomena accompanying the high mitotic activity found especially in the germinal centres of the lymphoid follicles. (4) There are many unanswered questions about the coexistence of the phosphatases and cholinesterases in the same places; their concomitant association in the lymphatic tissue may represent a special case within the framework of a more general mechanism.