Synaptic connections of the centrifugal fibers in the pigeon retina

The centrifugal fibers in the pigeon retina end in the inner nuclear layer and form two kinds of terminals, convergent and divergent. In the inner nuclear layer the fibers synapse with amnacrine and displaced ganglion cells. Because of their great number and their even distribution these fibers appear to constitute a system for the localized centrifugal control of the retinal functions.

Familial occurrence of persistent Mullerian structures in otherwise normal males

Eight cases of males with persistent Müllerian structures are reported in four pairs of unrelated siblings. A genetically inherited failure to produce or to respond to the Müllerian-inhibiting substance elaborated by the fetal testis is postulated.

Biogeography rather than association with cyanobacteria structures symbiotic microbial communities in the marine sponge Petrosia ficiformis

The sponge Petrosia ficiformis is ubiquitous in the Mediterranean Sea and Eastern Atlantic Ocean, hosting a diverse assemblage of bacteria, including, in illuminated sites, cyanobacteria. Two closely related sponge color morphs have been described, one inside caves and at their entrance (white/pink), and one on the rocky cliffs (violet). The presence of the different morphs and their ubiquity in the Mediterranean (from North-West to South-East) provides an opportunity to examine which factors mostly affect the associated microbial communities in this species: (i) presence of phototrophic symbionts or (ii) biogeography. 16S rRNA gene tag pyrosequencing data of the microbial communities revealed that Chloroflexi, Gammaproteobacteria, and Acidobacteria dominated the bacterial communities of all sponges analyzed. Chlorophyll a content, TEM observations and DNA sequence data confirmed the presence of the cyanobacterium Synechococcus feldmannii in violet and pink morphs of P. ficiformis and their absence in white color morphs. Rather than cyanobacterial symbionts (i.e., color morphs) accounting for variability in microbial symbiont communities, a biogeographic trend was observed between P. ficiformis collected in Israel and Italy. Analyses of partial 18S rRNA and mitochondrial cytochrome c oxidase subunit I (COX1) gene sequences revealed consistent genetic divergence between the violet and pink-white morphotypes of P. ficiformis. Overall, data indicated that microbial symbiont communities were more similar in genetically distinct P. ficiformis from the same location, than genetically similar P. ficiformis from distant locations.

Glass-Coated Tungsten Microelectrodes

Unusually rugged microelectrodes for recording the activity of single nerve cells or fibers can be constructed from tapered tungsten wire on which a glass capillary is collapsed and surface bonded. Tip diameter in the range between 1 and 5 microns provides relatively low impedance detection of extracellular potentials.

Effects of metal oxide nanoparticles on soil properties

In recent years the behavior and properties of nanoparticles released to the environment have been studied extensively to better assess the potential consequences of their broad use in commercial products. The fate, transport and mobility of nanoparticles in soil were shown to be strongly dependent on environmental conditions. However, little is known about the possible effects of nanoparticles on soil chemical, physical and biological properties. In this study, two types of metal oxide nanoparticles, CuO and Fe(3)O(4) were mixed into two types of soil and the effects of the nanoparticles on various soil properties were assessed. Metal oxide nanoparticles were shown previously to catalyze the oxidation of organic pollutants in aqueous suspensions, and they were therefore expected to induce changes in the organic material in the soil, especially upon addition of an oxidant. It was found that the nanoparticles did not change the total amount of organic materials in the soil or the total organic carbon in the soil extract; however, three-dimensional fluorescence spectroscopy demonstrated changes in humic substances. The nanoparticles also affected the soil bacterial community composition, based on denaturing gradient gel electrophoresis (DGGE) fingerprinting, but had little impact on the macroscopic properties of the soil.

Seasonal effect and anthropogenic impact on the composition of the active bacterial community in Mediterranean orchard soil

Several anthropogenic interventions, common in agriculture, may influence active bacterial communities in soil without affecting their total composition. Therefore, the composition of an active bacterial community in soil may reflect its relation to biogeochemical processes. This issue was addressed during two consecutive years in olive-orchard soil, irrigated with treated wastewater (TWW) in a Mediterranean climate, by following the active (rRNA) and total (rRNA gene) bacterial community in the soil. Although TWW irrigation did not affect the composition of the total soil bacterial community, it had an effect on the active fraction of the community. These results, based on 16S rRNA data, indicate that the organic matter and minerals in TWW were not directly utilized for the rapid proliferation of specific taxonomic groups. Activity levels, manifested by variance in the relative abundance of the active and total communities of selected operational taxonomic units, revealed annual and seasonal fluctuations and fluctuations dependent on the type of irrigation. The potential activity (nitrification rates) and community composition of ammonia-oxidizing bacteria were affected by TWW irrigation, and this group of bacteria was therefore further explored. It was concluded that irrigation with TWW had little effect on "who is there", i.e. which bacteria were present, but influenced "who is active", with a distinct effect on bacteria associated with the biochemical cycling of nitrogen.

Host Specificity and Spatial Distribution Preference of Three Pseudomonas Isolates

Plant hosts recruit and maintain a distinct root-associated microbiota based on host and bacterium traits. However, past studies disregarded microbial strain-host specificity and spatial micro-heterogeneity of the root compartment. Using genetic manipulation, confocal laser scanning microscopy, real-time quantitative PCR, and genome sequencing we characterized the colonization patterns of three Pseudomonas spp. isolates native to wheat roots, on the micro-scale. Namely, isolates P. fluorescens NT0133, P. stutzeri NT124, and P. stutzeri NT128. All three isolates preferentially colonized wheat over cucumber roots that served as control for host specificity. Furthermore, not only had the isolates strong host specificity but each isolate had a distinct spatial distribution on the root, all within a few millimeters. Isolate P. stutzeri-NT0124 preferentially colonized root tips, whereas P. fluorescens-NT0133 showed a preference for zones distant from the tip. In contrast, isolate P. stutzeri-NT0128 had no preference for a specific niche on the root. While all isolates maintained genetic potential for motility and biofilm formation their phenotype varied significantly and corresponded to their niche preference. These results demonstrate the importance of spatial colonization patterns, governed by both niche and bacterial characteristics which will have great importance in future attempts to manipulate the plant microbiome by constructing synthetic microbial consortia.

The effect of prophylaxis with ertapenem versus cefuroxime/metronidazole on intestinal carriage of carbapenem-resistant or third-generation-cephalosporin-resistant Enterobacterales after colorectal surgery

OBJECTIVES

Compared to cephalosporin-based prophylaxis, ertapenem prophylaxis lowers the risk of surgical site infection among carriers of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PEs) undergoing colorectal surgery. We aimed to determine whether ertapenem prophylaxis leads to increased postoperative colonization with carbapenem-resistant Enterobacterales (CREs) and third-generation-cephalosporin-resistant Enterobacterales (3GCR-Es).

METHODS

This study was nested within a quality improvement study of prophylaxis for ESBL-PE carriers undergoing colorectal surgery. Patients were screened 4-6 days after surgery for carriage of ESBL-PEs or other 3GCR-Es and CREs. When CREs were detected, pre- and postsurgical clones were compared using Fourier-transform infrared (FT-IR) spectroscopy.

RESULTS

The sample consisted of 56 patients who carried ESBL-PEs before surgery and received cefuroxime/metronidazole prophylaxis (Group 1), 66 who carried ESBL-PEs before surgery and received ertapenem (Group 2), and 103 ESBL-PE non-carriers who received cefuroxime/metronidazole prophylaxis (Group 3). CRE carriage was detected postoperatively in one patient (1.5%) in Group 2 versus eight patients (14.3%) in Group 1 (RD -12.8%; 95%CI -22.4% to -3.1%). For seven out of nine patients, preoperative ESBL-PE and postoperative CRE isolates were compared; in five of them, the pre- and postoperative clones were identical. Postoperative 3GCR-E carriage was detected in 37 patients (56.1%) in Group 2 versus 46 patients in Group 1 (82.1%) (aRD -20.7%, 95%CI -37.3% to -4.1%).

CONCLUSIONS

Among ESBL-PE carriers undergoing colorectal surgery, detection of short-term postsurgical colonization by CREs and 3GCR-Es was significantly lower among patients who received ertapenem prophylaxis than those who received cephalosporin-metronidazole prophylaxis. Resistance development in a colonizing bacterial clone, rather than carbapenemase acquisition, was the major mechanism of carbapenem resistance.

Plasma cortisol levels in malnourished children with and without superimposed acute stress

Plasma cortisol levels were measured in 13 children with marasmus, in 7 with kwashiorkor, and in 24 normal children. Cortisol levels in the malnourished children did not differ from those of the normal group, either before or after 15 or 30 days of treatment, unless there was superimposed acute stress. Stress caused by complications such as hypoglycaemia, infection, hypothermia, or acidosis led to raised plasma cortisol levels.

Investigation of Outbreaks of Extended-Spectrum Beta-Lactamase-Producing Klebsiella Pneumoniae in Three Neonatal Intensive Care Units Using Whole Genome Sequencing

Infections caused by extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) are on a constant rise and are a noted cause of outbreaks in neonatal intensive care units (NICUs). We used whole genome sequencing (WGS) to investigate the epidemiology of consecutive and overlapping outbreaks caused by ESBL-KP in NICUs in three hospitals in close proximity. Clonality of 43 ESBL-KP isolates from 40 patients was determined by BOX-PCR. Short-read sequencing was performed on representative isolates from each clone. The dominant clones from each NICU were sequenced using long-read sequencing. Bioinformatics methods were used to define multilocus sequence type (MLST), analyze plasmid content, resistomes, and virulence factors. In each NICU, we found a unique dominant clone (ST985, ST37, and ST35), each belonging to a distinct sequence type (ST), as well as satellite clones. A satellite strain in NICU-2 (ST35) was the dominant strain in NICU-3, where it was isolated four weeks later, suggesting transmission. NICU-1- and NICU-2-dominant strains had bla_CTX-M-15 carried on a similar transposable element (Tn3-ISEcp1) but at different locations: on a plasmid and on the chromosome, respectively. We concluded that the overlapping ESBL-KP outbreaks were a combination of clonal transmission within NICUs, possible transposable element transmission between NICUs, and repeated importation of ESBL-KP from the community.

The primate median eminence. II. Correlative high-voltage transmission electron microscopy

The ultrastructure of the normal median eminence of the male rhesus monkey (Macaca mulatta) is described using high-voltage electron microscopy. Surface specializations of ependymal cells lining the infundibular recess included cilia, apical extrusions, and microvilli. Supraependymal cells were predominantly macrophage-like, but examples of lymphocytic types were also seen. Tanycytes had long, branching, basal processes filled with numerous microtubules, some lipid droplets, and granules. The zona interna was composed of large unmyelinated neurosecretory fibers. A few myelinated fibers were also seen, but their character as neurosecretory fibers could not be established. The zona externa was composed of densely-packed profiles of neuro secretory fibers of small diameter, was well-vascularized and contained the terminations of tanycytes. Perivascular glial cells, vesiculated elements, pituicytes, and cellular elements common to connective tissue were observed. The intricate relationships between both the cellular and fibrous elements of the median eminence can be appreciated with the capability of high-voltage electron microscopy to discern ultrastructure in sections 10 times thicker than those used for low-voltage electron microscopy. The median eminence of this primate species has an ultrastructural organization similar to that described for most other species.

Safety and efficacy of a rice-based oral rehydration salt solution in the treatment of diarrhea in infants less than 6 months of age

The safety and efficacy of a rice-based oral rehydration salt (ORS) solution for the treatment of acute diarrhea in infants < 6 months of age was compared to those of a standard glucose-based ORS solution. A total of 97 infants aged 1-6 months who had a history of acute diarrhea for 120 h or less and showed signs of mild to moderate dehydration and no complications was recruited. Subjects were assigned to two treatment groups and received either standard glucose-based ORS solution or rice-based ORS solution until cessation of diarrhea. There was no significant difference between the two treatment groups with regard to the main outcome variables, including total stool output (84 [95% confidence interval (CI), 56-126] vs. 106 (95% CI, 76-148) g/kg], total ORS solution intake [171 (95% CI, 149-197) vs. 187 (95% CI, 161-218) ml/kg], or duration of diarrhea (35 +/- 31 vs 38 +/- 32 h). In addition, the fact that there was no difference between treatment groups in the presence of reducing substances in the stools suggests that rice was digested and absorbed by these infants. The results of our study support the conclusion that for infants < 6 months of age, rice-based ORS solution is safe and as efficacious as standard glucose-based ORS solution in the treatment of acute diarrhea.

"Hybrid" synapses formed by foreign innervation of parasympathetic neurons: a model for selectivity during competitive reinnervation

Selectivity of synapse formation after nerve regeneration was tested in the parasympathetic cardiac ganglion of frogs (Rana pipiens). First, we tested the ability of somatic motor axons to establish synaptic connections with denervated ganglion cells by implanting the hypoglossus nerve into the vagotomized heart. After several weeks, stimulation of the implanted hypoglossus mediated a parasympathetic-like inhibition of the heart rate, and synaptic responses produced by hypoglossal stimulation were recorded intracellularly in ganglion cells. Light and electron microscopy indicated that implanted hypoglossal nerve terminals contacted parasympathetic ganglion cells only on their axons and not on the cell body (where most vagal synapses are found in control animals). Second, we tested whether regenerating vagal preganglionic axons would complete with foreign (hypoglossal) terminals for innervation of cardiac ganglion cells. We allowed the vagus nerve to regenerate in animals in which the implanted hypoglossus had established functional contacts with the cardiac ganglion. Vagal axons were able to reinnervate the heart and reestablish synaptic connections on the cell bodies of ganglion cells. Furthermore, functional transmission at the foriegn (hypoglossal) terminals disappeared concomitant with vagal reinnervation.

Renal function in protein-energy malnutrition

So far, most studies on renal function in children with advanced protein-energy malnutrition have shown an impairment of glomerular filtration rate and renal plasma flow, as well as diminished ability to excrete an acid load and a concentrated urine. Investigation of these functions in eight marasmic infants and eight children with kwashiorkor once they were free of obvious infections and acute electrolyte disturbances has shown a practically normal renal performance.

Localization of neurophysin in the rat supraoptic nucleus. I. Ultrastructural immunocytochemistry using the post-embedding technique

Localization of neurophysin in neurons of the supraoptic nucleus was accomplished using an unlabeled-antibody, post-embedding, immunoperoxidase technique. Neurophysin was exclusively associated with neurosecretory granules within cell bodies of supraoptic neurons and their processes.

Multiplex lateral flow immunochromatographic assay is an effective method to detect carbapenemases without risk of OXA-48-like cross reactivity

BACKGROUND

It is essential to detect carriers of carbapenemase-producing Enterobacterales in order to implement infection control measures. The objectives of this study was to evaluate the NG-Test® CARBA 5 (CARBA 5) assay for detection of five carbapenemases and to assess the cross reactivity of other OXA-type carbapenemases with the OXA-48-like specific antibodies.

METHODS

A total of 197 Enterobacterales isolates were tested. To evaluate the cross reactivity, 73 carbapenem-resistant A. baumannii, harboring OXA-type variants, were tested. Polymerase chain reaction (PCR) served as gold standard for carbapenemase identification.

RESULTS

Excellent agreement was found between PCR and CARBA 5, for all but one isolate. The single false positive result (a blaSME positive S. marcescens isolate) was incorrectly positive for blaOXA-48 by CARBA 5. No cross reactivity was observed. The sensitivity and specificity were 100.0% and 98.0%, respectively.

CONCLUSIONS

The CARBA 5 assay is highly sensitive and specific and is recommended as a tool for the detection of the main carbapenemases of interest in clinical microbiology laboratories.

Increased Capsule Thickness and Hypermotility Are Traits of Carbapenem-Resistant Acinetobacter baumannii ST3 Strains Causing Fulminant Infection

Background

Acinetobacter baumannii is a successful nosocomial pathogen, causing severe, life-threatening infections in hospitalized patients, including pneumonia and bloodstream infections. The spread of carbapenem-resistant Acinetobacter baumannii (CRAB) strains is a major health threat worldwide. The successful spread of CRAB is mostly due to its highly plastic genome. Although some virulence factors associated with CRAB have been uncovered, many mechanisms contributing to its success are not fully understood.

Methods

Here we describe strains of CRAB that were isolated from fulminant cases in 2 hospitals in Israel. These isolates show a rare hypermucoid (HM) phenotype and were investigated using phenotypic assays, comparative genomics, and an in vivo Galleria mellonella model.

Results

The 3 isolates belonged to the ST3 international clonal type and were closely related to each other, as shown by Fourier-transform infrared spectroscopy and phylogenetic analyses. These isolates possessed thickened capsules and a dense filamentous extracellular polysaccharides matrix as shown by transmission electron microscopy (TEM), and overexpressed the capsule polysaccharide synthesis pathway-related wzc gene.

Conclusions

The HM isolates possessed a unique combination of virulence genes involved in iron metabolism, protein secretion, adherence, and membrane glycosylation. HM strains were more virulent than control strains in 2 G. mellonella infection models. In conclusion, our findings demonstrated several virulence factors, all present in 3 CRAB isolates with rare hypermucoid phenotypes.

Metabolic adaptation in protein-energy malnutrition

The metabolic response to chronic undernutrition covers a wide spectrum that ranges from decreased growth velocity in mild cases to profound distortion of body silhouette and composition and functional derangements in advanced stages of the protein-energy malnutrition-infection complex. A wide gamut of molecular, enzymatic, and hormonal processes assure a temporary availability of endogenous nutrients and the maintenance of vital functions.

Serum-ionized calcium in mexican protein-energy malnourished children

BACKGROUND

Hypocalcemia occurring in children with severe primary protein-energy malnutrition (PEM) has previously been shown to merely reflect a reduction in the protein-bound fraction of serum calcium. On the other hand, ultrafilterable, i.e., nonprotein bound calcium (Ca(U)), remains unaffected. The aim of the present investigation was to test the hypothesis that in infantile PEM, ionized calcium, which represents the major and physiologically most important component of Ca(U), is also kept within a normal concentration, whatever the total serum calcium levels.

METHODS

Three milliliters of peripheral venous blood were obtained on admission and periodically afterward from 18 fasting marasmic infants and 6 children with the edematous form of PEM (kwashiorkor). Ionized calcium was determined in 125 microL aliquots of blood serum with ion-selective electrodes. The measurement of related elements and molecules was carried out with customary laboratory procedures.

RESULTS

On admission, as well as during the ensuing stages of nutritional recovery, ionized serum calcium exhibited a normal concentration, with the exception of two initial samples. Total calcium, total protein, albumin, and inorganic phosphate concentrations were decreased in a variable degree according to the clinical type, ascending to normal levels during recovery.

CONCLUSIONS

Ionized calcium serum concentration remains within normal limits in severe infantile PEM.

OXA-900, a Novel OXA Sub-Family Carbapenemase Identified in Citrobacter freundii, Evades Detection by Commercial Molecular Diagnostics Tests

Using whole-genome sequencing and cloning of the target gene, we identified bla_OXA-900 carbapenemase, a novel bla_OXA belonging to a distant and distinct sub-family of bla_OXA-48-like. The plasmid-mediated gene was identified in a C. freundii isolate with elevated carbapenem MICs that evaded detection by commercial DNA-based methods. The novel gene, an OXA-48 family carbapenem-hydrolyzing class D β-lactamase, OXA-900, likely originates from marine environmental Shewanella. Since this plasmid-mediated gene has entered a member of the Enterobacterales and evades detection by commonly used tests, it may gain wide dissemination among Enterobacterales.