4,150 research outputs found
Uniqueness Of Larval Releasing Of Littoraria Scabra L. (Gastropoda: Littorinidae), In Tombariri Mangrove, North Sulawesi,Indonesia
Penelitian yang amat langka di alam ini menemukan kebaharuan keunikan strategi reproduksi Littoraria. scabra, di waktu kopulasi jantan berperan seks terbalik menyedot sebagian telur yang dibuahi dan dierami telur-telur yang dibuahi dalam tubuhnya sampai menetas menjadi larva-larva serta melepaskan larva-larva tersebut di bulan penuh dan baru yang mengikuti siklus pasang selama penelitian. Temuan amat langka kedua keunikan strategi reproduksi L. scabra, yang amat langka di alam dengan pasangan jantan-betina lagi kawin melepaskan larva-larva baik jantan maupun betina pada siklus bi-lunar bersamaan dengan siklus pasang selama penelitian
Cytotoxic, mutagenic and carcinogenic properties of ultraviolet radiation : shining light on photolesions
Exposure to ultraviolet light (UV light) poses a serieus threat to human health. An altered life style
(holidays in the sun, tanning devices) has led to increased exposure to UV light in the Western
population. UV light damages the DNA, the carrier of genetic information, which can result in
permanent alterations in the genome and, ultimately, cancer. The majority of the DNA lesions induced
by UV light consists of cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6,4)-pyrimidone
photoproducts (6-4PPs). The relative contribution of these CPDs and 6-4PPs to the effects of acute
and chronic UV exposure, however, is nat known (e.g. sunburn, cancer). Although organisms are
equipped with the nucleotide excision repair (NER) mechanism for remaval of lesions, this mechanism
may nat offer sufficient proteetion in cases of excessive exposure to UV light. The aim of this thesis is
to further elucidate the mechanisms behind the detrimental effects of UV exposure and to determine
the role of individual classes of UV-induced DNA lesions in these processes. To this end, we generated
mice transgenically expressing photolyase enzymes. This approach enables light-controlled remaval of
a single type of lesion, allowing investigation of the contribution of individual lesions to UV responses.
In Chapter 1, we review the current knowledge on UV-induced DNA damage and repair, and the
consequences of UV exposure on human health. Chapters 2 and 3 describe the generation of
ubiquitously expressing CPD and 6-4PP photolyase transgenie mice. We show that these marsupial and
plant photolyase gene products are functional in mice, resulting in light-dependent remaval of DNA
lesions from mouse skin. Furthermore, we provide evidence that CPDs are responsible for adverse UV
effects including cell death, sunburn and permanent genomic alterations (mutations). In Chapter 4
we describe the generation of transgenie mice expressing photolyase from the keratinocyte-specific
K14 promoter, allowing fast remaval of DNA damage by photoreactivation in basal keratinocytes of the
epidermis, whereas in other cell types such as fibroblasts and Langerhans cells lesions are repaired
in slow fashion (if at all). This gave us the unique opportunity to dissect the cell types involved in
UV responses. In Chapter 5 the carcinogenic potentia
Spectrum of injuries associated with paediatric ACL tears: an MRI pictorial review
OBJECTIVE: Magnetic resonance imaging (MRI) findings in anterior cruciate ligament (ACL) injury are well known, but most published reviews show obvious examples of associated injuries and give little focus to paediatric patients. Here, we demonstrate the spectrum of MRI appearances at common sites of associated injury in adolescents with ACL tears, emphasising age-specific issues. METHODS: Pictorial review using images from children with surgically confirmed ACL tears after athletic injury. RESULTS: ACL injury usually occurs with axial rotation in the valgus near full extension. The MRI findings can be obvious and important to management (ACL rupture), subtle but clinically important (lateral meniscus posterior attachment avulsion), obvious and unimportant to management (femoral condyle impaction injury), or subtle and possibly important (medial meniscocapsular junction tear). Paediatric-specific issues of note include tibial spine avulsion, normal difficulty visualising a thin ACL and posterolateral corner structures, and differentiation between incompletely closed physis and impaction fracture. CONCLUSION: ACL tear is only the most obvious sign of a complex injury involving multiple structures. Awareness of the spectrum of secondary findings illustrated here and the features distinguishing them from normal variation can aid in accurate assessment of ACL tears and related injuries, enabling effective treatment planning and assessment of prognosis. TEACHING POINTS: • The ACL in children normally appears thin or attenuated, while thickening and oedema suggest tear. • Displaced medial meniscal tears are significantly more common later post-injury than immediately. • The meniscofemoral ligaments merge with the posterior lateral meniscus, complicating tear assessment. • Tibial plateau impaction fractures can be difficult to distinguish from a partially closed physis. • Axial MR sequences are more sensitive/specific than coronal for diagnosis of medial collateral ligament (MCL) injury
The Ecological Adaptive Significance of Littoraria Scabra for Their Survivorship in Extreme Mangrove Environment of Tombariri
Penelitian ini menemukan bahwa signifikansi ekologi Littoraria scabra untuk survival di mikrohabitat mangrove Tombariri yang ekstrim adalah sebagai berikut berfungsi sebagai tempat istirahat, menghindari perendaman air, mencari makanan, meletakkan larva, menghindar cahaya dan bersembunyi dari predator-predator. Signifikansi L. scabra distribusi spasial mengelompok untuk mereduksi stres kekeringan, suhu, terlepas di substrat akibat gelombang, aktivitas makan, reproduksi, kecocokan habitat. Signifikansi distibusi mengelompok dengan populasi tinggi untuk mengimbangi kuatnya predasi serta merespons tekanan seleksi alam yang kuat demi kelangsungan hidupnya
Nuclear targeting of the serine protease granzyme A (fragmentin-1)
Cytolytic granule-mediated target cell killing is effected in part through synergistic action of the membrane-acting protein perforin and serine proteases such as granzymes A (GrA) or B (GrB). In the present study we examine GrA cellular entry and nuclear uptake in intact mouse myeloid FDC-P1 cells exposed to perforin using confocal laser scanning microscopy, as well as reconstitute GrA nuclear uptake in vitro. GrA alone was found to be able to enter the cytoplasm of intact cells but did not accumulate in nuclei. In the presence of perforin, it specifically accumulated in the cell nuclei, with maximal levels about 2.5 times those in the cytoplasm after 2. 5 hours. In vitro, GrA accumulated in the nucleus and nucleolus maximally to levels that were four- and sixfold, respectively, those in the cytoplasm. In contrast, the active form of the apoptotic cysteine protease CPP32 did not accumulate in nuclei in vitro. Nuclear/nucleolar import of GrA in vitro was independent of ATP and not inhibitable by the non-hydrolyzable GTP analog GTPgammaS, but was dependent on exogenously added cytosol. Importantly, GrA was found to be able to accumulate in the nucleus of semi-intact cells in the presence of the nuclear envelope-permeabilizing detergent CHAPS, implying that the mechanism of nuclear accumulation was through binding to insoluble factors in the nucleus. GrB was found for the first time to be similar in this regard. The results support the contention that GrA and GrB accumulate in the nucleus through a novel nuclear import pathway, and that this is integral to induction of the nuclear changes associated with cytolytic granule-mediated apoptosis.David A. Jans, Lyndall J. Briggs, Patricia Jans, Christopher J. Froelich, Gayathri Parasivam, Sharad Kumar, Vivien R. Sutton and Joseph A. Trapan
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