The human microbiome contains a vast array of microbes and genes that show greater complexity than the host's own karyome; the functions of many of these microbes are beneficial and show co-evolution with the host, while others are detrimental. The microbiota that colonises the gut is now being considered as a virtual organ or emergent system, with properties that need to be integrated into host biology and physiology. Unlike other organs, the functions that the gut microbiota plays in the host are as yet not fully understood and can be quite easily disrupted by antibiotics, diet or surgery. In this review, we look at some of the best-characterised functions that only the gut microbiota plays and how it interacts with the host's endocrine system and we try to make it clear that the 21st-century biology cannot afford to ignore this facet of biology, if it wants to fully understand what makes us human.

The authors have identified important clinical predictors of admission in acute bronchiolitis. This information has been used to develop a simple clinical risk scoring system to aid decision making in the emergency department.

Major technologic advances in magnetic resonance (MR) imaging, including the advent of novel pulse sequences (eg, diffusion-weighted and steady-state free precession sequences) and the use of hepatocyte-specific contrast agents, have led to better image quality and shorter acquisition times, resulting in dramatic improvements in the noninvasive detection and characterization of hepatic lesions, particularly hypervascular neoplasms. However, as the role of MR imaging in clinical evaluation of the liver continues to evolve, keeping abreast of new developments can be daunting as well as confusing. A systematic approach that makes use of a simple decision algorithm can help differentiate hypervascular hepatic lesions on the basis of their distinguishing MR imaging characteristics and related clinical information.

Cured meat products are subject to a type of bacterial spoilage in which the cured meat pigment is oxidized to a greenish or faded color. The microorganisms responsible for this effect appear to be a fairly restricted group of catalasenegative, salt-tolerant microorganisms that are capable of growing at low temperatures, and are able to oxidize certain substrates in the meat product with the accumulation of hydrogen peroxide. The most common organism isolated in this laboratory that is associated with this type of spoilage has been a heterofermentative Lactobacillum described by Niven, Castelani, and Alanson (1949). On the basis of detailed physiological and serological studies, this organism appeared to be a hitherto undescribed species. The cultures were reported to grow rather poorly in a wide variety of laboratory media. In view of the economic importance of this organism and its apparently unusual nutritive requirements, an investigation of its nutrition has been undertaken.

The aetiology of Parkinson's disease (PD) is yet to be fully understood but it is becoming more and more evident that neuronal cell death may be multifactorial in essence. The main focus of PD research is to better understand substantia nigra homeostasis disruption, particularly in relation to the wide-spread deposition of the aberrant protein α-synuclein. Microarray technology contributed towards PD research with several studies to date and one gene, ALDH1A1 (Aldehyde dehydrogenase 1 family, member A1), consistently reappeared across studies including the present study, highlighting dopamine (DA) metabolism dysfunction resulting in oxidative stress and most probably leading to neuronal cell death. Neuronal cell death leads to increased inflammation through the activation of astrocytes and microglia. Using our dataset, we aimed to isolate some of these pathways so to offer potential novel neuroprotective therapeutic avenues. To that effect our study has focused on the upregulation of P2X7 (purinergic receptor P2X, ligand-gated ion channel, 7) receptor pathway (microglial activation) and on the NOS3 (nitric oxide synthase 3) pathway (angiogenesis). In summary, although the exact initiator of striatal DA neuronal cell death remains to be determined, based on our analysis, this event does not remain without consequence. Extracellular ATP and reactive astrocytes appear to be responsible for the activation of microglia which in turn release proinflammatory cytokines contributing further to the parkinsonian condition. In addition to tackling oxidative stress pathways we also suggest to reduce microglial and endothelial activation to support neuronal outgrowth.

The Editorial Board of this Bulletin (1 954) has s u m m a rized concisely the c u r r e n t status of the generic names Micrococcus and Staphylococcus, and has asked f o r comments and suggestions.The first auestion r a i s e d is whether Microcbccus luteus (Schroeter) C o b is a recognizable species. Breed [m) has reviewed the l i t e r a t u r e and indicates that this species should be defined a s non-liquefying, non-nitrate reducing, yellow-pigmented coccus capable of utilizing ammoniacal nitrogen as a sole source of nitrogen. He a l s o suggests that ATCC culture 398 would make a satisfactory type culture. Gibson (1953) r e j e c t s the validity of this species because the suggested type s t r a i n does not grow in an ammonium t a r t r a t e -salts medium .We have studied recently ATCC culture 398, in addition to a collection of named s t r a i n s of micrococci, kindly supplied by Dr. Breed. In confirmation with Dr. Gibson's claim, s t r a i n 398 failed to grow i n Cohn's ammonium t a rt r a t e medium o r on Hucker's ammonium phosphate-glucose medium. Nine of the s t r a i n s in the collection w e r e reported to have grown in such media when first isolated, but at the p r e s e n t time only 2 of these 9 s t r a i n s retained this characteristic.F u r t h e r investigation revealed that the cultures failed to grow because of their inability to utilize t a r t r a t e or glucose a s an energy source. Our present knowledge of the nutrition of these organisms a l s o indicates that these t e s t s a r e dependent upon carrying over the required vitamins i n the inoculum. Therefore, we consider such t e s t s for a mmonia utilization inapplicable to this group of organisms. Journal paper No. 113, American Meat I n s t i t u t e Foundat ion.

Most aerobic and facultative bacteria contain a cytochrome system that serves as a terminal electron carrier during aerobic respiration. The majority of these bacteria also produce catalase that can decompose any hydrogen peroxide that might be produced by flavoprotein oxidases. These two iron-porphyrin systems generally are not present in anaerobic bacteria or in lactic acid bacteria. This correlation has led to employment of the simple test for catalase as a general test for iron-porphyrin systems, and a negative catalase test is a common criterion for differentiating lactic acid bacteria from morphologically similar organisms. However, catalase-positive lactic acid bacteria have been described (

The standard diagnostic test for differentiating staphylococci from micrococci is based on the ability of the former to produce acid anaerobically in a glucose-containing growth medium. This test has been modified to provide greater convenience, easier interpretation of results, and better correlation with deoxyribonucleic acid (DNA) base composition. In the modified test, shake cultures in Brewer's fluid thioglycolate medium with 0.3% agar added are observed for growth in the anaerobic zone of the tubes. This test was applied to 125 strains of staphylococci and micrococci, and all except two strains gave results that were consistent with other criteria. Of particular interest were eight strains of Micrococcus saprophyticus and three strains of M. lactis that have a DNA composition of 30 to 37% guanine plus cytosine (GC). All 11 of these cultures produced anaerobic growth and thus would be classified as staphylococci. Strains of M. lactis that have a high GC content in their DNA grew only aerobically. Some cultures of staphylococci produced characteristic band patterns of anaerobic growth and other cultures produced only a few anaerobic colonies from an inoculum of 106 to 107 cells. These observations suggest some interesting genetic and metabolic capabilities in such cultures.