The complete cDNA for a human mitochondrial protein designated P1, which was previously identified as a microtubule-related protein, has been cloned and sequenced. The deduced amino acid sequence of P1 shows strong homology (40 to 50% identical residues and an additional 20% conservative replacements) to the 65-kilodalton major antigen of mycobacteria, to the GroEL protein of Escherichia coli, and to the ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) subunit binding protein of plant chloroplasts. Similar to the case with the latter two proteins, which have been shown to act as chaperonins in the posttranslational assembly of oligomeric protein structures, it is suggested that P1 may play a similar role in mammalian cells. The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.Our earlier studies with mutants of Chinese hamster ovary (CHO) cells selected for resistance to the microtubule (MT) inhibitor podophyllotoxin showed that a large number of these mutants involved specific electrophoretic alteration in a major protein designated P1 (Mr, 63 kilodaltons [kDa]) (6, 7). The genetic lesion in these mutants appears to be related to the cellular action of the drug, since podophyllotoxinresistant mutants exhibit highly specific cross-resistance and collateral sensitivity to other MT inhibitors, such as colchicine, nocodazole, and taxol, and show reduced binding of the drug in cell extracts (6, 7). Immunofluorescence studies show that in interphase cells of vertebrate and invertebrate species, P1 antibody stains mitochondria, which show specific association with MTs (5, 7). Subfractionation of rat mitochondria has localized P1 to the matrix compartment (4). To help understand the cellular function of P1, cloning and sequencing of P1 cDNA from human cells was undertaken. The P1 sequence reported here shows extensive sequence and structural homology to a family of bacterial and plant proteins, termed chaperonins (8), which are involved in facilitating the posttranslational assembly of oligomeric protein complexes (1,3,8), as well as to the 65-kDa major antigenic protein of mycobacterial species (15,(18)(19)(20). The observed high degree of sequence and structural similarity between these proteins strongly indicates that P1 is the human homolog of this evolutionarily highly conserved group of proteins.Isolation of Pl-specific clones from kgtll libraries. We have previously demonstrated that our antibodies to P1 crossreact only with the P1 protein in one-and two-dimensional immunoblots of proteins from CHO and human cells (5, 7).

Despite the fact that feeding a very low birth weight (VLBW) neonate is a fundamental and inevitable part of its management, this is a field which is beset with controversies. Optimal nutrition improves growth and neurological outcomes, and reduces the incidence of sepsis and possibly even retinopathy of prematurity. There is a great deal of heterogeneity of practice among neonatologists and pediatricians regarding feeding VLBW infants. A working group on feeding guidelines for VLBW infants was constituted in McMaster University, Canada. The group listed a number of important questions that had to be answered with respect to feeding VLBW infants, systematically reviewed the literature, critically appraised the level of evidence, and generated a comprehensive set of guidelines. These guidelines form the basis of this state-of-art review. The review touches upon trophic feeding, nutritional feeding, fortification, feeding in special circumstances, assessment of feed tolerance, and management of gastric residuals, gastro-esophageal reflux, and glycerin enemas.

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The genes for two different 70-kDa heat shock protein (HSP70) homologs have been cloned and sequenced from the protozoan Giardia lambiba. On the basis of their sequence features, one of these genes corresponds to the cytoplasmic form of HSP70. The second gene, on the basis of its characteristic N-terminal hydrophobic signal sequence and C-tenal endoplasmic reticulum (ER) retention sequence (Lys-Asp-Glu-Leu), is the equivalent of ER-resident GRP78 or the Bip family of proteins. To test this hypothesis we undertook to clone HSP70 homologs from the protozoan Giardia lamblia, which lacks mitochondria (6) and which, on the basis of 16S rRNA phylogeny, constitutes the earliest diverging member within the eukaryotic lineage (7). In the present paper we describe the cloning and sequence comparison of two HSP70 homologs from G. lamblia.t One of these homologs apparently corresponds to the cytoplasmic form of the protein, whereas the other bears various characteristics of the form present in the endoplasmic reticulum (ER) (see refs. 3 and 8). Detailed comparison and phylogenetic analyses of these and other eukaryotic and prokaryotic HSP70 sequences presented here provide important insight into the origin of eukaryotic cells and of ER.

Heat shock induces the synthesis of a set of proteins in Halobacterium marismortui whose molecular sizes correspond to the known major heat shock proteins. By using the polymerase chain reaction and degenerate oligonucleotide primers for conserved regions of the 70-kDa heat shock protein (HSP70) family, we All bacterial and eukaryotic species studied to date exhibit increased synthesis of a set of proteins referred to as stress or heat shock proteins (HSPs) in response to a sudden increase in physiological temperature as well as exposure to other stressors (e.g., hypoxia, amino acid analogs, ethanol, etc.) (27,34). One of the proteins whose synthesis is greatly induced under these conditions has an apparent molecular mass of 70 kDa (HSP70; bacterial homolog known as the DnaK protein). Although the synthesis of HSP70 is greatly enhanced by various physiological stressors, it also constitutes a major protein under normal growth conditions and has been shown to be essential for cellular growth. Gene cloning and sequencing studies on HSP70 show that the primary structure of this protein has been highly conserved during evolution in species ranging from bacteria to plants to humans (27,34).In recent years, although HSP70 homologs have been cloned from numerous bacterial and eukaryotic species (1,2,4,6,12,14,18,21,32,37,38,41,42)

The Hsp60 and Hsp70 chaperones contain a number of conserved inserts that are restricted to particular phyla of bacteria. A one aa insert in the E. coli GroEL and a 21-23 insert in the DnaK proteins are specific for most Gram-negative bacteria. Two other inserts in DnaK are limited to certain groups of proteobacteria. The requirement of these inserts for cellular growth was examined by carrying out complementation studies with temperature-sensitive (T(s)) mutants of E. coli groEL or dnaK. Our results demonstrate that deletion or most changes in these inserts completely abolished the complementation ability of the mutant proteins. Studies with GroEL and DnaK from some other species that either lacked or contained these inserts also indicated that these inserts are essential for growth of E. coli. The DnaK from some bacteria contains a two aa insert that is not found in E. coli. Introduction of this insert into the E. coli DnaK also led to its inactivation, indicating that these inserts are specific for different groups. We postulate that these conserved inserts that are localized in loop regions on protein surfaces, are involved in some ancillary functions that are essential for the groups of bacteria where they are found.

Objective: The purpose of this study was to evaluate the demographic and treatment characteristics of neonates (X37 weeks' estimated gestational age) who were admitted to a neonatal intensive care unit (NICU) for a diagnosis of meconium aspiration syndrome (MAS) during the years 1997 to 2007. The goals in studying this group of neonates were to better estimate the magnitude of abnormal outcomes and to determine the proportion of these infants exposed to specific therapeutic interventions.Study Design: Retrospective review of an administrative de-identified data set.Result: A total of 415 772 neonates formed the starting data set and 162 075 (39%) were X37 weeks. Of the 162 075 term neonates, 7518 (1.8% of all neonates and 4.6% of term NICU admissions) had an admission diagnosis of MAS. In the 7518 neonates, the following outcomes were observed: 6124 (81.5%) were discharged home; 679 (9%) were acutely transferred to a higher level of intensive care; 416 (5.5%) were transferred to another clinical service within the hospital; 178 (2.4%) were transferred to another NICU for convalescent care and 88 (1.2%) died. There were 33 (0.4%) who did not have data on outcome at discharge. During the period between 2002 and 2005, acute transfer rates decreased (12.4 to 9%) and the reported rate for death remained relatively constant between 0.9 and 1.5%. There were 107 (1.4%) neonates who were treated (n ¼ 61) with, or transferred, for extracorporeal membrane oxygenation (ECMO) (n ¼ 46). Three of the sixty-one neonates (4.9%) who were treated with ECMO died. Conclusion:Term neonates who are admitted with a diagnosis of MAS continue to represent a high-risk population with significant morbidity, and they often require intensive therapies.

MicroGenomicsEvolutionary relationships among photosynthetic prokaryotes (Heliobacterium chlorum, Chloro¯exus aurantiacus, cyanobacteria, Chlorobium tepidum and proteobacteria): implications regarding the origin of photosynthesis Radhey S. Gupta, * Tariq Mukhtar and Bhag Singh Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada L8N 3Z5. SummaryThe presence of shared conserved insertions or deletions in proteins (referred to as signature sequences) provides a powerful means to deduce the evolutionary relationships among prokaryotic organisms. This approach was used in the present work to deduce the branching orders of various eubacterial taxa consisting of photosynthetic organisms. For this purpose, portions of the Hsp60 and Hsp70 genes, covering known signature sequence regions, were PCR-ampli®ed and sequenced from Heliobacterium chlorum, Chloro¯exus aurantiacus and Chlorobium tepidum. This information was integrated with sequence data for several other proteins from numerous species to deduce the branching orders of different photosynthetic taxa. Based on signature sequences that are present in different proteins, it is possible to infer that the various eubacterial phyla evolved from a common ancestor in the following order: low GC Gram-positive (H. chlorum ) ! high GC Gram-positive ! Deinococcus±Thermus ! green non-sulphur bacteria (Cf. aurantiacus ) ! cyanobacteria ! spirochaetes ! Chlamydia±Cytophaga±Aquifex ±¯avobacteria±green sulphur bacteria (Cb. tepidum ) ! proteobacteria (a, d and e) and ! proteobacteria (b and g). The members of the Heliobacteriaceae family that contain a Fe±S type of reaction centre (RC-1) and represent the sole photosynthetic phylum from the Gram-positive or monoderm group of prokaryotes are indicated to be the most ancestral of the photosynthetic lineages.Among the Gram-negative bacteria or diderm prokaryotes, green non-sulphur bacteria such as Cf. aurantiacus, which contains a pheophytin±quinone type of reaction centre (RC-2), are indicated to have evolved very early. Thus, the organisms containing either RC-1 or RC-2 existed before the evolution of cyanobacteria, which contain both these reaction centres to carry out oxygenic photosynthesis. The eubacterial divisions consisting of green sulphur bacteria and proteobacteria are indicated to have diverged after cyanobacteria. Some implications of these results concerning the origin of photosynthesis and the earliest prokaryotic fossils are discussed.