In Vitro HIV-1 LTR Integration into T-Cell Activation Gene CD27 Segment and the Decoy Effect of Modified-Sequence DNA

Integration into the host genome is an essential step in the HIV-1 life cycle. However, the host genome sequence that is favored by HIV-1 during integration has never been documented. Here, we report that CD27, a T cell activation gene, includes a sequence that is a target for in vitro HIV-1 cDNA integration. This sequence has a high affinity for integrase, and the target nucleotides responsible for this higher affinity were identified using a crystal microbalance assay. In experiments involving a segment of the CD27 gene, integration converged in the target nucleotides and flanking sequence DNA, indicating that integration is probably dependent upon the secondary structure of the substrate DNA. Notably, decoy modified CD27 sequence DNAs in which the target nucleotides were replaced suppressed integration when accompanying the original CD27 sequence DNA. Our identified CD27 sequence DNA is useful for investigating the biochemistry of integrase and for in vitro assessment of integrase-binding inhibitors.     

Axial Diffusivity of the Corona Radiata at 24 Hours Post-Stroke: A New Biomarker for Motor and Global Outcome

Fractional anisotropy (FA) is an effective marker of motor outcome at the chronic stage of stroke yet proves to be less efficient at early time points. This study aims to determine which diffusion metric in which location is the best marker of long-term stroke outcome after thrombolysis with diffusion tensor imaging (DTI) at 24 hours post-stroke. Twenty-eight thrombolyzed patients underwent DTI at 24 hours post-stroke onset. Ipsilesional and contralesional FA, mean (MD), axial (AD), and radial (RD) diffusivities values were calculated in different Regions-of-Interest (ROIs): (1) the white matter underlying the precentral gyrus (M1), (2) the corona radiata (CoRad), (3) the posterior limb of the internal capsule (PLIC) and (4) the cerebral peduncles (CP). NIHSS scores were acquired at admission, day 1, and day 7; modified Rankin Scores (mRS) at 3 months. Significant decreases were found in FA, MD, and AD of the ipsilesional CoRad and M1. MD and AD were also significantly lower in the PLIC. The ratio of ipsi and contralesional AD of the CoRad (CoRad-rAD) was the strongest diffusion parameter correlated with motor NIHSS scores on day 7 and with the mRS at 3 months. A Receiver-Operator Curve analysis yielded a model for the CoRad-rAD to predict good outcome based on upper limb NIHSS motor scores and mRS with high specificity and sensitivity. FA values were not correlated with clinical outcome. In conclusion, axial diffusivity of the CoRad from clinical DTI at 24 hours post-stroke is the most appropriate diffusion metric for quantifying stroke damage to predict outcome, suggesting the importance of early axonal damage.     

Regional excitatory and inhibitory amino acid levels in epileptic El mouse brain

Inbred mutant El mice are highly susceptible to convulsive seizures upon tossing stimulation. The levels of excitatory (e.g. glutamate and aspartate) and inhibitory amino acids [e.g. -aminobutyrate (GABA)] were examined in discrete regions of stimulated El mice [El(+)] non-stimulated El mice [El(-)] and ddY mice, which do not have convulsive disposition. In comparison with ddY, a general increased levels of aspartate, glutamate, glutamine, and taurine were detected in brain regions of El(-). The levels of GABA and glycine were almost the same in ddY and El(-). Compared to El(+), the levels of aspartate, glutamate, glutamine, and GABA in El(-) were either the same or higher. In the case of taurine and glycine, the levels in El(-) were either the same or lower than El(+). Alanine is special in that El(-) have a higher level than El(+) in hippocampus but lower in cerebellum. Furthermore, while marked changes were registered in several brain regions, none of the amino acids investigated showed any significant differences in the hypothalamus of three different groups of mice.     

Increased choline acetyltransferase activity by Chinese herbal medicine Sho-saiko-to-go-keishi-ka-shakuyaku-to in aged rat brain

The effect of a Chinese herbal medicine Sho-saiko-to-go-keishi-ka-shakuyaku-to (TJ-960) on the brain choline acetyltransferase (CAT) activity was studied in adult (3.5 months of age) and aged (24 months of age) rats. After oral administration of 5% TJ-960 solution for 3 months, CAT activity in the hippocampus, pons-medulla oblongata and striatum of aged rats was significantly lower than that of adult rats. CAT activity in the cerebellum, however, was significantly higher in the aged rats, as compared to the adult rats. TJ-960 significantly increased CAT activity in the hippocampus and striatum of aged rats, but did not affect the activity of the enzyme in the adult rat brain.     

Neutrophil polarisation in plasma differs to that induced by endogenous chemoattractants with regard to frequency of uropod formation and requirement for divalent cations.

Human neutrophils suspended in Hanks' balanced salt solution (37° C, 20 mM Hepes, pH 7.2) produced extensions, elongated and developed a polarised morphology with both a pseudopod and uropod when exposed to C5a (10 nM), leukotriene B4 (10 nM), platelet activating factor (40 nM) or interleukin-8 (12.5 nM). Responses to each mediator were generally enhanced or unaffected by chelators of extracellular Ca²⁺ and Mg²⁺. Neutrophils suspended in heparinised plasma (90-10% v/v in Hanks' balanced salt solution) produced extensions, elongated and developed a pseudopod, but rarely developed a uropod unless additional Mg²⁺ ions (0.5-5 mM) were added. These findings demonstrate that the polarisation of neutrophils in plasma is significantly different to that induced by endogenous chemoattractants with regard to the frequency of uropod formation and requirement for extracellular divalent cations.     

药用寄生植物菟丝子属,列当属和无根藤属氨基酸的分析

本文测定了菟丝子属、列当属和无根藤属某些种的种子和植株氨基酸的种类组成和含量。结果表明,3个属种子和植株氨基酸均在15种以上,且含量丰富,特别是必需氨基酸的含量较高。文中讨论了氨基酸的药用和在种子鉴定与化学分类上的作用,探讨了开发应用的前景。     

Environmental vibrio phage–bacteria interaction networks reflect the genetic structure of host populations

Phages depend on their bacterial hosts to replicate. The habitat, density and genetic diversity of host populations are therefore key factors in phage ecology, but our ability to explore their biology depends on the isolation of a diverse and representative collection of phages from different sources. Here, we compared two populations of marine bacterial hosts and their phages collected during a time series sampling program in an oyster farm. The population of Vibrio crassostreae, a species associated specifically to oysters, was genetically structured into clades of near clonal strains, leading to the isolation of closely related phages forming large modules in phage–bacterial infection networks. For Vibrio chagasii, which blooms in the water column, a lower number of closely related hosts and a higher diversity of isolated phages resulted in small modules in the phage–bacterial infection network. Over time, phage load was correlated with V. chagasii abundance, indicating a role of host blooms in driving phage abundance. Genetic experiments further demonstrated that these phage blooms can generate epigenetic and genetic variability that can counteract host defence systems. These results highlight the importance of considering both the environmental dynamics and the genetic structure of the host when interpreting phage–bacteria networks.     

Homologous and heterologous regulation of the helodermin/vasoactive-intestinal-peptide response in the murine radiation leukemia-virus-induced lymphoma cell line BL/VL3

1. Functional vasoactive intestinal peptide (VIP)/helodermin receptors and beta 2-adrenoceptors coexist in membranes from a cultured cloned BL/VL3 cell line of murine T-cell lymphoma induced by a radiation leukemia virus (see preceding paper in this journal). 2. Short-term (5-30 min) exposures of BL/VL3 cells to VIP or isoproterenol induced both homologous and heterologous desensitization. The potency of VIP and isoproterenol to desensitize was similar to their potency to occupy receptors and activate adenylate cyclase. 3. Long-term (16-h) exposure of BL/VL3 cells to VIP induced homologous down regulation only, whereas isoproterenol induced both homologous and heterologous down regulation. The potency of VIP, peptide histidine isoleucinamide, helodermin, helospectin, and [D-Phe2]VIP on the one hand, and of isoproterenol on the other hand, to decrease homologous responses was comparable to their potency for receptor occupancy and adenylate cyclase activation.