Direct detection of chicken genomic DNA for gender determination by thymine-DNA glycosylase.

1. Birds, especially nestlings, are generally difficult to sex by morphology and early detection of chick gender in ovo in the hatchery would facilitate removal of unwanted chicks and diminish welfare objections regarding culling after hatch. 2. We describe a method to determine chicken gender without the need for PCR via use of Thymine-DNA Glycosylase (TDG). TDG restores thymine (T)/guanine (G) mismatches to cytosine (C)/G. We show here, that like DNA Polymerase, TDG can recognise, bind and function on a primer hybridised to chicken genomic DNA. 3. The primer contained a T to mismatch a G in a chicken genomic template and the T/G was cleaved with high fidelity by TDG. Thus, the chicken genomic DNA can be identified without PCR amplification via direct and linear detection. Sensitivity was increased using gender specific sequences from the chicken genome. 4. Currently, these are laboratory results, but we anticipate that further development will allow this method to be used in non-laboratory settings, where PCR cannot be employed.

A modular chitin-binding protease associated with hemocytes and hemolymph in the mosquito Anopheles gambiae.

Sp22D, a modular serine protease encompassing chitin binding, low density lipoprotein receptor, and scavenger receptor cysteine-rich domains, was identified by molecular cloning in the malaria vector, Anopheles gambiae. It is expressed in multiple body parts and during much of development, most intensely in hemocytes. The protein appears to be posttranslationally modified. Its integral, putatively glycosylated form is secreted in the hemolymph, whereas a smaller form potentially generated by proteolytic processing is associated with the tissues. Bacterial challenge or wounding result in low-level RNA induction, but the protein does not bind to bacteria, nor is its processing affected by infection. However, Sp22D binds to chitin with high affinity and undergoes transient changes in processing during pupal to adult metamorphosis; it may respond to exposure to naked chitin during tissue remodeling or damage.

[Anomalties of the interatrial septum and latent atrial vulnerability in unexplained ischemic stroke in young adults]. / Anomalies du septum interauriculaire et vulnérabilité auriculaire latente dans l'accident vasculaire cérébral ischémique inexpliqué du sujet jeune.

Seventy-four consecutive patients (18 to 55 years) underwent programmed atrial stimulation in the investigation of unexplained ischaemic stroke after a full work-up including transoesophageal echocardiography to exclude abnormalities of the interatrial septum (patent foramen ovale and/or atrial septal aneurysm). The parameters recorded during atrial electrophysiological investigation were: the effective atrial refractory period, loco-regional intra-atrial conduction, the index of latent atrial vulnerability and the inducibility by the extrastimulus technique. Seventy five per cent of patients with a patent foramen ovale and/or an atrial septal aneurysm were inducible compared with only 38% of patients with normal interatrial septa on transoesophageal echocardiography (p = 0.001). Fifty two per cent of patients with an anomaly of the atrial septum had latent atrial vulnerability compared with 26% of those with normal transoesophageal echocardiography (p = 0.02). These results confirm the relationship between atrial septal anomalies and latent atrial vulnerability in unexplained ischaemic stroke of young adults.

Frequency stabilization of a frequency-doubled 1556-nm source to the 5S(1/2) ? 5D (5/2) two-photon transitions of rubidium.

Improvements in the power level of sources near 1550 nm and in the efficiency of waveguide frequency doublers enabled us to lock a frequency-doubled source directly to the 5S(1/2) ? 5D(5/2) two-photon transitions near 778 nm. We obtained a sufficiently powerful second-harmonic signal, exceeding 2 mW, by doubling an external-cavity diode laser that was amplified by an erbium-doped fiber amplifier in a periodically poled LiNbO(3) channel waveguide. Our experimental scheme can be used for realizing compact, high-performance frequency standards near 1550 nm for fiber-optic communication and sensing applications.

Identification of phytoplasmas in eggs, nymphs and adults of Scaphoideus titanus Ball reared on healthy plants.

A survey for the presence of aster yellows-related phytoplasmas in the different life stages of Scaphoideus titanus was carried out by means of PCR and nested-PCR assays. Using a phytoplasma 16Srl group-specific primer pair followed by RFLP analysis of amplified products, we were able to detect and identify phytoplasmas from eggs, newly hatched nymphs, fourth and fifth instar nymphs and adults reared on ten phytoplasma-free Vicia faba seedlings. Two of these broad beans became infected, whereas PCR failed to detect phytoplasmas in the same ten plants before leafhopper rearing. These results suggest the possibility of transovarial transmission of aster yellows-related phytoplasmas in S. titanus.