LEA Gene Introns: is the Intron of Dehydrin Genes a Characteristic of the Serine-Segment?

Dehydrins, which belong to group 2 LEA proteins, are a family of intrinsically unstructured plant proteins that accumulate during the late stages of embryogenesis and in response to abiotic stresses. We have previously reported that the OpsDHN1 gene, encoding an SK₃-type acidic dehydrin protein from Opuntia streptacantha, contains an intron inserted within the sequence encoding the S-motif. Herein, we present an in silico analysis of intron sequences in dehydrin genes from mono- and dicotyledonous plants that reveals a preference for insertion within the nucleotide sequence encoding the S-motif. Sequence comparison of ten Dhn genes from Arabidopsis thaliana and the orthologous genes in Arabidopsis lyrata revealed that introns maintain considerable sequence identity and conserve the insertion pattern. Furthermore, syntenic regions were identified among eight orthologous genes of A. thaliana and A. lyrata, showing that correlated gene arrangements are conserved between these Arabidopsis species. Our study shows that most SKn-type dehydrins contain one intron that is conserved in phase and location; this intron is linked to the nucleotide sequence that encodes the S-motif.     

On the altitudinal limits of birds on BasilC Peak (Bioko Island; Equatorial Guinea)

Pérez del Val, J. 2000. On the altitudinal limits of birds on Basile Peak (Bioko Island; Equatorial Guinea). Ostrich 71(1 & 2): 342.

The lower altitudinal limit of the montane avifauna in Africa has generally been set at 1 500- 800 m, corresponding to vegetation belts of the main mountain ranges of East Africa. However, much lower limits have been reported from the East Usambaras (Tanzania), Mount Cameroon, and Bioko Island. Basilé Peak is a volcano of 3 011 m which constitutes the northern half of Bioko Island. Below 400–900 m the forest has been logged and largely replaced by cocoa plantations, but the vegetation is relatively undisturbed at higher altitudes. Annual rainfall ranges between 2 000 mm and 3 500 mm. From January 1990 to July 1992 mist-nets were set at 13 standardised stations on Basilé Peak; 1 427 birds of 71 species were captured. Previous data from non-standardised mist-netting at 6 other localities, together with sight and sound records, published data, and 1 047 skins in the collections of Museo Naçional de Ciençias Naturales (Madrid), Estacion Biologica de Donaiia (Sevilla) and the Natural History Museum (Tring) were also used to compile distribution lists. From published botanical surveys, I recognised four vegetation zones: Lowland Rain Forest up to 800 m; Mountain Rain Forest at 80CL1 800 m; Araliaceus Forest 1 800–2 500 m; and Ericaceus Stands above 2 500 m. An analysis of similarity (using the index of Czechanowski) grouped 68 bird species into altitudinal classes at 200 m intervals. This suggests a division between lowland and montane birds at 800–1 000 m, broadly coinciding with the change between Lowland and Mountain Rain Forest. There does not seem to be a discrete bird community restricted to either of the upper zones (Araliaceus Forest or Ericaeus Stands), with only the Yellow Bishop Euplectes capensis restricted to the upper 500 m of the mountain. Most species which reach the summit are found in all vegetation zones, notably the endemic subspecies of the African Goshawk Accipiter tachiro lopezi. It is suggested that low temperatures, high rainfall, and in particular the seasonal distribution of rainfall, may explain the lower altitudinal limits of the montane avifauna on Bioko and on Mount Cameroon.     

Structural Changes in Dengue Virus When Exposed to a Temperature of 37°C

Previous binding studies of antibodies that recognized a partially or fully hidden epitope suggest that insect cell-derived dengue virus undergoes structural changes at an elevated temperature. This was confirmed by our cryo-electron microscopy images of dengue virus incubated at 37°C, where viruses change their surface from smooth to rough. Here we present the cryo-electron microscopy structures of dengue virus at 37°C. Image analysis showed four classes of particles. The three-dimensional (3D) map of one of these classes, representing half of the imaged virus population, shows that the E protein shell has expanded and there is a hole at the 3-fold vertices. Fitting E protein structures into the map suggests that all of the interdimeric and some intradimeric E protein interactions are weakened. The accessibility of some previously found cryptic epitopes on this class of particles is discussed.     

On the limitations of standard statistical modeling in biological systems: A full Bayesian approach for biology

One of the most important scientific challenges today is the quantitative and predictive understanding of biological function. Classical mathematical and computational approaches have been enormously successful in modeling inert matter, but they may be inadequate to address inherent features of biological systems. We address the conceptual and methodological obstacles that lie in the inverse problem in biological systems modeling. We introduce a full Bayesian approach (FBA), a theoretical framework to study biological function, in which probability distributions are conditional on biophysical information that physically resides in the biological system that is studied by the scientist.     

Immunologic evaluation and validation of methods using synthetic peptides derived from Mycobacterium tuberculosis for the diagnosis of tuberculosis infection

The goal of this study was to demonstrate the usefulness of an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of pulmonary tuberculosis (PTB) and extrapulmonary TB (EPTB). This assay used 20 amino acid-long, non-overlapped synthetic peptides that spanned the complete Mycobacterium tuberculosis ESAT-6 and Ag85A sequences. The validation cohort consisted of 1,102 individuals who were grouped into the following five diagnostic groups: 455 patients with PTB, 60 patients with EPTB, 40 individuals with non-EPTB, 33 individuals with leprosy and 514 healthy controls. For the PTB group, two ESAT-6 peptides (12033 and 12034) had the highest sensitivity levels of 96.9% and 96.2%, respectively, and an Ag85A-peptide (29878) was the most specific (97.4%) in the PTB groups. For the EPTB group, two Ag85A peptides (11005 and 11006) were observed to have a sensitivity of 98.3% and an Ag85A-peptide (29878) was also the most specific (96.4%). When combinations of peptides were used, such as 12033 and 12034 or 11005 and 11006, 99.5% and 100% sensitivities in the PTB and EPTB groups were observed, respectively. In conclusion, for a cohort that consists entirely of individuals from Venezuela, a multi-antigen immunoassay using highly sensitive ESAT-6 and Ag85A peptides alone and in combination could be used to more rapidly diagnose PTB and EPTB infection.     

Callus induction and shoot organogenesis from anther cultures of Curcuma attenuata Wall

Curcuma attenuata is a highly valued ornamental. This study provides the first report on C. attenuata shoot organogenesis and plant regeneration. Immature anthers derived from 5 to 7?cm long inflorescences were isolated and cultured on different variations of Murashige and Skoog (MS) media to induce callus and then shoot organogenesis. When the 2-mm long anthers in which microspores were at the uninucleate developmental stage were cultured in the dark on MS medium containing 13.6???M 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.3???M kinetin (KT) for 15?days and then transferred to 40???mol?m^?2?s^?1 fluorescent light for 30?days, the percentage callus induction reached 33.3?%. After callus was transferred to various differentiation media and cultured in the light, 33.1?% of all callus cultures could differentiate into adventitious shoots on MS medium supplemented with 22.0???M 6-benzyladenine (BA), 0.53???M ??-naphthaleneacetic acid (NAA) and 1.4???M thidiazuron (TDZ) after culturing for 60?days. Over 95?% of plantlets survived after transplanting plantlets into trays with a mixture of sand and perlite (2: 1) for 20?days. Chromosome number, determined from the root tips of young plantlets, indicated that all plantlets were diploid (2n?=?84).     

Reproductive measures and chick provisioning of Cory's Shearwater Calonectris diomedea borealis in the Azores

Capsule Timing of breeding influenced wing-length at fledging, and egg size may be an indicator of fledging weight and the amount of food received by chicks.

Aims To investigate chick growth, temporal patterns of chick food provisioning and the importance of indices of parental condition or quality, egg size and hatching date, to predict nestling body mass and wing-length at fledging, and compare breeding and chick feeding characteristics between colonies in the northeast Atlantic.

Methods A survey of Cory's Shearwater nests was carried out at Vila islet. A sample of 52 chicks, ringed and weighed at hatching, was selected to study chick growth and food provisioning.

Results Hatching success (51%) was much lower than fledging success (87%). Both hatching date and egg size contributed to explain wing-length at fledging, but hatching date, which was negatively correlated with wing-length at fledging, had the most important contribution (22%). There was some indication that egg size may explain variation in fledging weight and the amount of food received by chicks. Food delivery and feeding frequency of chicks varied throughout the chick development stage and three phases were distinguished: (1) 0–29 days, the highest feeding frequency values and a linear increase in food delivery; (2) 30–69 days, an oscillation in food delivery and medium feeding frequencies; (3) 70–90+ days, a sharp decrease in both food delivery and feeding frequency.

Conclusion Variation in food availability did not seem sufficient to override the overall importance of indices of parental quality in determining reproductive measures and chick provisioning. Breeding and feeding characteristics were similar between colonies in the northeast Atlantic, with variability in chick provisioning higher further south.     

The emergence of neural activity and its role in the development of the enteric nervous system

The enteric nervous system (ENS) is a vital part of the autonomic nervous system that regulates many gastrointestinal functions, including motility and secretion. All neurons and glia of the ENS arise from neural crest-derived cells that migrate into the gastrointestinal tract during embryonic development. It has been known for many years that a subpopulation of the enteric neural crest-derived cells expresses pan-neuronal markers at early stages of ENS development. Recent studies have demonstrated that some enteric neurons exhibit electrical activity from as early as E11.5 in the mouse, with further maturation of activity during embryonic and postnatal development. This article discusses the maturation of electrophysiological and morphological properties of enteric neurons, the formation of synapses and synaptic activity, and the influence of neural activity on ENS development.     

Discovery and SAR of PF-4693627, a potent,selective and orally bioavailable mPGES-1 inhibitor for the potential treatment of inflammation

Inhibition of mPGES-1, the terminal enzyme in the arachidonic acid/COX pathway to regulate the production of pro-inflammatory prostaglandin PGE2, is considered an attractive new therapeutic target for safe and effective anti-inflammatory drugs. The discovery of a novel series of orally active, selective benzoxazole piperidinecarboxamides as mPGES-1 inhibitors is described. Structure–activity optimization of lead 5 with cyclohexyl carbinols resulted in compound 12, which showed excellent in vitro potency and selectivity against COX-2, and reasonable pharmacokinetic properties. Further SAR studies of the benzoxazole ring substituents lead to a novel series of highly potent compounds with improved PK profile, including 23, 26, and 29, which were effective in a carrageenan-stimulated guinea pig air pouch model of inflammation. Based on its excellent in vitro and in vivo pharmacological, pharmacokinetic and safety profile and ease of synthesis, compound 26 (PF-4693627) was advanced to clinical studies.