The Influence of Bioactive Oxylipins from Marine Diatoms on Invertebrate Reproduction and Development

Diatoms are one of the main primary producers in aquatic ecosystems and occupy a vital link in the transfer of photosynthetically-fixed carbon through aquatic food webs. Diatoms produce an array of biologically-active metabolites, many of which have been attributed as a form of chemical defence and may offer potential as candidate marine drugs. Of considerable interest are molecules belonging to the oxylipin family which are broadly disruptive to reproductive and developmental processes. The range of reproductive impacts includes; oocyte maturation; sperm motility; fertilization; embryogenesis and larval competence. Much of the observed bioactivity may be ascribed to disruption of intracellular calcium signalling, induction of cytoskeletal instability and promotion of apoptotic pathways. From an ecological perspective, the primary interest in diatom-oxylipins is in relation to the potential impact on energy flow in planktonic systems whereby the reproductive success of copepods (the main grazers of diatoms) is compromised. Much data exists providing evidence for and against diatom reproductive effects; however detailed knowledge of the physiological and molecular processes involved remains poor. This paper provides a review of the current state of knowledge of the mechanistic impacts of diatom-oxylipins on marine invertebrate reproduction and development.     

Experimental West Nile virus infection in Eastern Screech Owls (Megascops asio)

Eastern Screech Owls (EASOs) were experimentally infected with the pathogenic New York 1999 strain of West Nile virus (WNV) by subcutaneous injection or per os. Two of nine subcutaneously inoculated birds died or were euthanatized on 8 or 9 days postinfection (DPI) after <24 hr of lethargy and recumbency. All subcutaneously inoculated birds developed levels of viremia that are likely infectious to mosquitoes, with peak viremia levels ranging from 10(5.0) to 10(9.6) plaque-forming units/ml. Despite the viremia, the remaining seven birds did not display signs of illness. All birds alive beyond 5 DPI seroconverted, although the morbid birds demonstrated significantly lower antibody titers than the clinically normal birds. Cagemates of infected birds did not become infected. One of five orally exposed EASOs became viremic and seroconverted, whereas WNV infection in the remaining four birds was not evident. All infected birds shed virus via the oral and cloacal route. Early during infection, WNV targeted skin, spleen, esophagus, and skeletal muscle. The two morbid owls had myocardial and skeletal muscle necrosis and mild encephalitis and nephritis, whereas some of the clinically healthy birds that were sacrificed on 14 DPI had myocardial arteritis and renal phlebitis. WNV is a significant pathogen of EASOs, causing pathologic lesions with varying clinical outcomes.     

Immune regulation of canine tumour and macrophage PD‐L1 expression

Expression of programmed cell death receptor ligand 1 (PD‐L1) on tumor cells has been associated with immune escape in human and murine cancers, but little is known regarding the immune regulation of PD‐L1 expression by tumor cells and tumor‐infiltrating macrophages in dogs. Therefore, 14 canine tumor cell lines, as well as primary cultures of canine monocytes and macrophages, were evaluated for constitutive PD‐L1 expression and for responsiveness to immune stimuli. We found that PD‐L1 was expressed constitutively on all canine tumor cell lines evaluated, although the levels of basal expression were very variable. Significant upregulation of PD‐L1 expression by all tumor cell lines was observed following IFN‐γ exposure and by exposure to a TLR3 ligand. Canine monocytes and monocyte‐derived macrophages did not express PD‐L1 constitutively, but did significantly upregulate expression following treatment with IFN‐γ. These findings suggest that most canine tumors express PD‐L1 constitutively and that both innate and adaptive immune stimuli can further upregulate PD‐L1 expression. Therefore the upregulation of PD‐L1 expression by tumor cells and by tumor‐infiltrating macrophages in response to cytokines such as IFN‐γ may represent an important mechanism of tumor‐mediated T‐cell suppression in dogs as well as in humans.     

中加合作农业生态学“双语＋精品”课程建设的探索与实践

在国际教育合作背景下,福建农林大学引进的农业生态学（Agroecology）课程与福建省甚至全国高校双语课程相比具有独特的优势。本文回顾了中加合作《农业生态学》双语课程的引进和适应过程,以及其作为福建省＂精品课程＂的教学体系、风格、方式及其建设成效;最后作者提出从促进国际交流、加强教材建设和教学成果的推广应用等3方面努力把该课程建成国家级＂双语示范课程＂。     

Magnetic Field and Plasma Observations at Mars: Initial Results of the Mars Global Surveyor Mission

The magnetometer and electron reflectometer investigation (MAG/ER) on the Mars Global Surveyor spacecraft has obtained magnetic field and plasma observations throughout the near-Mars environment, from beyond the influence of Mars to just above the surface (at an altitude of approximately 100 kilometers). The solar wind interaction with Mars is in many ways similar to that at Venus and at an active comet, that is, primarily an ionospheric-atmospheric interaction. No significant planetary magnetic field of global scale has been detected to date (<2 x 10(21) Gauss-cubic centimeter), but here the discovery of multiple magnetic anomalies of small spatial scale in the crust of Mars is reported.     

Linking winter and summer events in a migratory bird by using stable-carbon isotopes

For migratory birds, early arrival and physical condition on the breeding grounds are important determinants of reproductive success and fitness. Differences in arrival times often exceed a month, and later arriving individuals are often in poorer condition. Habitat-specific isotopic signatures indicate that the quality of winter habitats occupied by American redstarts (Setophaga ruticilla) determines their physical condition and spring departure dates, which in turn result in variable arrival schedules and condition on temperate breeding grounds. These findings link events in tropical winter grounds with those in temperate breeding areas for a migratory songbird and provide evidence that winter habitats may be limiting.     

Adverse reaction to procaine penicillin G in horses

Adverse reactions to intramuscular injections of procaine penicillin G are reported in 11 horses, five of which died. The clinical findings are presented and suggest central nervous involvement in most cases. Post mortem findings in one horse were consistent with anaphylaxis whereas in other cases the clinical findings, duration of treatment, speed of onset and subsequent completion of treatment supports diagnosis of an acute procaine toxicity syndrome.