Pancreatic lipases: evolutionary intermediates in a positional change of catalytic carboxylates?

Comparison of the fold of lipases from Geotrichum candidum and from human pancreas identified a high degree of similarity which was not expected on the basis of their amino acid sequences. Although both enzymes utilize a serine protease-like catalytic triad, they differ in the topological position of the acid. We speculate that these proteins are evolutionarily related and that the pancreatic lipase is an evolutionary intermediate in the pathway of migration of the catalytic acid to a new position within the fold

Insights into interfacial activation from an open structure of Candida rugosa lipase.

The structure of the Candida rugosa lipase determined at 2.06-A resolution reveals a conformation with a solvent-accessible active site. Comparison with the crystal structure of the homologous lipase from Geotrichum candidum, in which the active site is covered by surface loops and is inaccessible from the solvent, shows that the largest structural differences occur in the vicinity of the active site. Three loops in this region differ significantly in conformation, and the interfacial activation of these lipases is likely to be associated with conformational rearrangements of these loops. The "open" structure provides a new image of the substrate binding region and active site access, which is different from that inferred from the structure of the "closed" form of the G. candidum lipase

Cloning and expression of Geotrichum candidum lipase II gene in yeast. Probing of the enzyme active site by site-directed mutagenesis.

The three-dimensional structure of lipase II of Geotrichum candidum strain ATCC34614 (GCL II) has provided insights with respect to the nature of the catalytic machinery of lipases. To support these structural observations, we have carried out an analysis of GCL II by mutagenesis. The gene encoding lipase II of Geotrichum candidum strain ATCC34614 (GCL II) was amplified using the polymerase chain reaction, cloned, and sequenced. The intronless lipase gene was expressed and secreted from Saccharomyces cerevisiae at approximately 5 mg/liter of culture. Recombinant GCL II was purified by immunoaffinity chromatography and characterized using a combination of substrates and independent analytical methods. The recombinant enzyme and the enzyme isolated from its natural source have comparable specific activities against triolein of about 1000 mumol of oleic acid released/min/mg of protein. The putative catalytic triad Ser217-His463-Glu354 was probed by site-directed mutagenesis. The substitution of Ser217 by either Cys or Thr and of His463 by Ala led to a complete elimination of the activity against both triolein and tributyrin. Substitution of Glu354 by either Ser, Ala or Gln renders the enzyme inactive and also perturbs the enzyme stability. However, the enzyme with the conservative replacement Glu354 Asp is stable and displays only a small decrease of triolein activity but a 10-fold decrease in activity against tributyrin. There was no appreciable difference in esterase activity between the native, recombinant wild type, and Glu354 Asp mutant. These results confirm that the triad formed by Ser217-Glu354-His463 is essential for catalytic activity. They also show that the active site of GCL II is more tolerant to a conservative change of the carboxylic side chain within the triad than are other hydrolases with similar catalytic triads

Screening performance of abbreviated versions of the UPSIT smell test.

“This is a post-peer-review, pre-copyedit version of a protocol published in Journal of Neurology. The final publication is available at https://doi.org/10.1007/s00415-019-09340-x"BACKGROUND: Hyposmia can develop with age and in neurodegenerative conditions, including Parkinson's disease (PD). The University of Pennsylvania Smell Identification Test (UPSIT) is a 40-item smell test widely used for assessing hyposmia. However, in a number of situations, such as identifying hyposmic individuals in large populations, shorter tests are preferable. METHODS: We assessed the ability of shorter UPSIT subsets to detect hyposmia in 891 healthy participants from the PREDICT-PD study. Shorter subsets included Versions A and B of the 4-item Pocket Smell Test (PST) and 12-item Brief Smell Identification Test (BSIT). Using a data-driven approach, we evaluated screening performances of 23,231,378 combinations of 1-7 smell items from the full UPSIT to derive "winning" subsets, and validated findings separately in another 191 healthy individuals. We then compared discriminatory UPSIT smells between PREDICT-PD participants and 40 PD patients, and assessed the performance of "winning" subsets containing discriminatory smells in PD patients. RESULTS: PST Versions A and B achieved sensitivity/specificity of 76.8%/64.9% and 86.6%/45.9%, respectively, while BSIT Versions A and B achieved 83.1%/79.5% and 96.5%/51.8%. From the data-driven analysis, 2 "winning" 7-item subsets surpassed the screening performance of 12-item BSITs (validation sensitivity/specificity of 88.2%/85.4% and 100%/53.5%), while a "winning" 4-item subset had higher sensitivity than PST-A, -B, and even BSIT-A (validation sensitivity 91.2%). Interestingly, several discriminatory smells featured within "winning" subsets, and demonstrated high-screening performances for identifying hyposmic PD patients. CONCLUSION: Using abbreviated smell tests could provide a cost-effective means of large-scale hyposmia screening, allowing more targeted UPSIT administration in general and PD-related settings

SARS Surveillance during Emergency Public Health Response, United States, March–July 2003

In response to the emergence of severe acute respiratory syndrome (SARS), the United States established national surveillance using a sensitive case definition incorporating clinical, epidemiologic, and laboratory criteria. Of 1,460 unexplained respiratory illnesses reported by state and local health departments to the Centers for Disease Control and Prevention from March 17 to July 30, 2003, a total of 398 (27%) met clinical and epidemiologic SARS case criteria. Of these, 72 (18%) were probable cases with radiographic evidence of pneumonia. Eight (2%) were laboratory-confirmed SARS-coronavirus (SARS-CoV) infections, 206 (52%) were SARS-CoV negative, and 184 (46%) had undetermined SARS-CoV status because of missing convalescent-phase serum specimens. Thirty-one percent (124/398) of case-patients were hospitalized; none died. Travel was the most common epidemiologic link (329/398, 83%), and mainland China was the affected area most commonly visited. One case of possible household transmission was reported, and no laboratory-confirmed infections occurred among healthcare workers. Successes and limitations of this emergency surveillance can guide preparations for future outbreaks of SARS or respiratory diseases of unknown etiology

Evaluation of lymph node numbers for adequate staging of Stage II and III colon cancer

<p>Abstract</p> <p>Background</p> <p>Although evaluation of at least 12 lymph nodes (LNs) is recommended as the minimum number of nodes required for accurate staging of colon cancer patients, there is disagreement on what constitutes an adequate identification of such LNs.</p> <p>Methods</p> <p>To evaluate the minimum number of LNs for adequate staging of Stage II and III colon cancer, 490 patients were categorized into groups based on 1-6, 7-11, 12-19, and ≥ 20 LNs collected.</p> <p>Results</p> <p>For patients with Stage II or III disease, examination of 12 LNs was not significantly associated with recurrence or mortality. For Stage II (HR = 0.33; 95% CI, 0.12-0.91), but not for Stage III patients (HR = 1.59; 95% CI, 0.54-4.64), examination of ≥20 LNs was associated with a reduced risk of recurrence within 2 years. However, examination of ≥20 LNs had a 55% (Stage II, HR = 0.45; 95% CI, 0.23-0.87) and a 31% (Stage III, HR = 0.69; 95% CI, 0.38-1.26) decreased risk of mortality, respectively. For each six additional LNs examined from Stage III patients, there was a 19% increased probability of finding a positive LN (parameter estimate = 0.18510, p < 0.0001). For Stage II and III colon cancers, there was improved survival and a decreased risk of recurrence with an increased number of LNs examined, regardless of the cutoff-points. Examination of ≥7 or ≥12 LNs had similar outcomes, but there were significant outcome benefits at the ≥20 cutoff-point only for Stage II patients. For Stage III patients, examination of 6 additional LNs detected one additional positive LN.</p> <p>Conclusions</p> <p>Thus, the 12 LN cut-off point cannot be supported as requisite in determining adequate staging of colon cancer based on current data. However, a minimum of 6 LNs should be examined for adequate staging of Stage II and III colon cancer patients.</p

Group B Streptococcus vaccine development: present status and future considerations, with emphasis on perspectives for low and middle income countries.

Globally, group B Streptococcus (GBS) remains the leading cause of sepsis and meningitis in young infants, with its greatest burden in the first 90 days of life. Intrapartum antibiotic prophylaxis (IAP) for women at risk of transmitting GBS to their newborns has been effective in reducing, but not eliminating, the young infant GBS disease burden in many high income countries. However, identification of women at risk and administration of IAP is very difficult in many low and middle income country (LMIC) settings, and is not possible for home deliveries. Immunization of pregnant women with a GBS vaccine represents an alternate pathway to protecting newborns from GBS disease, through the transplacental antibody transfer to the fetus in utero. This approach to prevent GBS disease in young infants is currently under development, and is approaching late stage clinical evaluation. This manuscript includes a review of the natural history of the disease, global disease burden estimates, diagnosis and existing control options in different settings, the biological rationale for a vaccine including previous supportive studies, analysis of current candidates in development, possible correlates of protection and current status of immunogenicity assays. Future potential vaccine development pathways to licensure and use in LMICs, trial design and implementation options are discussed, with the objective to provide a basis for reflection, rather than recommendations

Multi-ancestry genome-wide association meta-analysis of Parkinson?s disease

Although over 90 independent risk variants have been identified for Parkinson’s disease using genome-wide association studies, most studies have been performed in just one population at a time. Here we performed a large-scale multi-ancestry meta-analysis of Parkinson’s disease with 49,049 cases, 18,785 proxy cases and 2,458,063 controls including individuals of European, East Asian, Latin American and African ancestry. In a meta-analysis, we identified 78 independent genome-wide significant loci, including 12 potentially novel loci (MTF2, PIK3CA, ADD1, SYBU, IRS2, USP8, PIGL, FASN, MYLK2, USP25, EP300 and PPP6R2) and fine-mapped 6 putative causal variants at 6 known PD loci. By combining our results with publicly available eQTL data, we identified 25 putative risk genes in these novel loci whose expression is associated with PD risk. This work lays the groundwork for future efforts aimed at identifying PD loci in non-European populations

Structure and Function of Macromolecular Antifreezes (Peptide, Glycopeptide, Fish)

100 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.Many polar fishes are protected from freezing by peptide or glycopeptide antifreezes which inhibit ice growth. The relationship between the structures of these molecules and the mechanism by which they work in investigated in this thesis.Glycopeptide antifreezes range in molecular weight from 2600-33,000 daltons and most are polymers of the tripeptide ala-ala-thr. Each threonine is glycosidically linked to the disaccharide galactose-N-acetylgalactosamine. The glycopeptide antifreezes from Microgadus tomcod and Eleginus gracilis are unique, however, in that they contain arginine. Determination of the amino acid sequences of these antifreezes indicates that glycopeptide antifreeze structure is highly conserved. Arginine occasionally replaces the glycosidically linked threonine in these sequences, but the basic tripeptide repeat is otherwise maintained.The large glycopeptides are more efficient inhibitors of ice growth than are the small proline containing glycopeptides. Although the secondary structures of the glycopeptides are uncertain, some investigators have proposed some ordered structures and have suggested that the proline residues of the small glycopeptides may disrupt this structure and reduce their effectiveness. The results presented in this study, however, indicate that the observed differences in effectiveness between different sizes of glycopeptide antifreezes can be attributed entirely to differences in molecular size rather than differences in conformation.A model of peptide antifreeze function is based on the structure of the winter flounder peptide. Polar amino acids are periodically spaced in this peptide and the spacing of the polar residues in a helical conformation is presumed to allow efficient hydrogen bonding of the antifreeze of the ice surface. Some investigators predicted that all peptide antifreezes would be similarly arranged. Peptide antifreezes were isolated from the zoarcids Rhigophila dearborni and Lycodes polaris. No periodic placement of polar groups is evident in the amino acid sequences and CD indicates little or no helical structure in these peptides. The secondary structure of these peptides remains uncertain, but a large amount of (beta)-structure is predicted from the amino acid sequences. Peptide antifreeze structures clearly show substantial variation.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD