1,034 research outputs found
Sperm ultrastructure of an oviparous and an ovoviviparous onychophoran species (Peripatopsidae) with some phylogenetic considerations
The spermatozoa of the Australian oviparous Ooperipatellus insignis and the South African ovoviviparous Opisthopatus cinctipes (both: Onychophora, Peripatopsidae) were studied and compared with the spermatozoal patterns already described in the taxon. The spermatozoa of both species conform with the general plan described for the Onychophora: they are filiform cells formed, in sequence, by an elongated, fully condensed nucleus capped by an acrosome and surrounded by several spiral ridges; by a mitochondrial midpiece characteristically interpolated between the nucleus and a characteristic flagellum. Major differences between the spermatozoa of both species concern their acrosome organization. The correlation between the acrosomal pattern and the size and structure of the ovarial eggs (oocytes) in onychophorans has been investigated. A parsimony analysis was performed on 21 spermatozoal characters of the species considered. Its results are congruent with those of the traditional systematics. A new set of autapomorphies characterising onychophoran sperm is suggested and some of the spermatological homologies proposed between Onychophora and Euclitellata spermatozoa are critically discussed. Our analysis suggests that spermatozoal characters are good phylogenetic markers among onychophorans, also at low taxonomic level. Zusammenfassung Die Ultrastruktur der Spermien zweier Onychophoren-Arten (Peripatopsidae) wird vergleichend untersucht. Erstmals wird ein oviparer Vertreter berucksichtigt; namlich Ooperipatellus insignis vom Locus typicus; Mt. Macedon, Victoria, Australien. Seine Spermatozoen werden mit denen der ovoviviparen sudafrikanischen Art Opisthopatus cinctipes verglichen. Die Ergebnisse dieser Untersuchung werden mit verfugbaren Literaturdaten abgeglichen und ein Grundmuster fur Onychophoren-Spermien entwickelt. Die Spermien der beiden hier untersuchten Arten stimmen in ihrer Morphologie und Ultrastruktur im Wesentlichen mit dem bereits fur Onychophoren bekannten Muster uberein. Es sind fadige Zellen, die recht einheitlich aufgebaut sind. Sie weisen einen langlichen, kompakten Kern mit Akrosom-Kappe auf und sind spiralig von Furchen umgeben. Der mitochondriale Mittelbereich der Spermien liegt zwischen dem Nukleus und einem fur Onychophoren typischen Flagellum. Unterschiede betreffen dagegen die Organisation des Onychophoren-Akrosoms. Die mogliche Korrelation zwischen Akrosom-Ausbildung und Grose und Struktur der Ovarialeier wird untersucht. Basierend auf 21 Spermatozoen-Charakteren wird eine Parsimonie-Analyse durchgefuhrt. Die so gewonnenen Daten decken sich mit denjenigen der traditionellen Systematik. Die Spermien der Onychophoren weisen Merkmale auf, welche Autapomorphien des Taxon Onychophora sein konnen. Daruber hinaus werden mutmasliche Spermien-Homologien, die von verschiedenen Autoren fur die Taxa Onychophora und Euclitellata vorgeschlagen wurden, kritisch bewertet. Unsere Analyse zeigt, dass Spermien-Merkmale fur Onychophoren gute phylogenetische Marker darstellen, sogar auf Art-Niveau
Divergence of AMP Deaminase in the Ice Worm Mesenchytraeus solifugus (Annelida, Clitellata, Enchytraeidae)
Glacier ice worms, Mesenchytraeus solifugus and related species, are the largest glacially obligate metazoans. As one component of cold temperature adaptation, ice worms maintain atypically high energy levels in an apparent mechanism to offset cold temperature-induced lethargy and death. To explore this observation at a mechanistic level, we considered the putative contribution of 5′ adenosine monophosphate deaminase (AMPD), a key regulator of energy metabolism in eukaryotes. We cloned cDNAs encoding ice worm AMPD, generating a fragment encoding 543 amino acids that included a short N-terminal region and complete C-terminal catalytic domain. The predicted ice worm AMPD amino acid sequence displayed conservation with homologues from other mesophilic eukaryotes with notable exceptions. In particular, an ice worm-specific K188E substitution proximal to the AMP binding site likely alters the architecture of the active site and negatively affects the enzyme's activity. Paradoxically, this would contribute to elevated intracellular ATP levels, which appears to be a signature of cold adapted taxa
A general interpolation scheme for thermal fluctuations in superconductors
We present a general interpolation theory for the phenomenological effects of
thermal fluctuations in superconductors. Fluctuations are described by a simple
gauge invariant extension of the gaussian effective potential for the
Ginzburg-Landau static model. The approach is shown to be a genuine variational
method, and to be stationary for infinitesimal gauge variations around the
Landau gauge. Correlation and penetration lengths are shown to depart from the
mean field behaviour in a more or less wide range of temperature below the
critical regime, depending on the class of material considered. The method is
quite general and yields a very good interpolation of the experimental data for
very different materials.Comment: some misprints have been corrected in Eq.(15),(19); more references
and comments have been adde
Surgery-Guided Removal of Ovarian Cancer Using Up-Converting Nanoparticles
Ovarian cancer survival and the recurrence rate are drastically affected by the amount of tumor that can be surgically removed prior to chemotherapy. Surgeons are currently limited to visual inspection, making smaller tumors difficult to be removed surgically. Enhancing the surgeon’s ability to selectively remove cancerous tissue would have a positive effect on a patient’s prognosis. One approach to aid in surgical tumor removal involves using targeted fluorescent probes to selectively label cancerous tissue. To date, there has been a trade-off in balancing two requirements for the surgeon: the ability to see maximal tumors and the ability to identify these tumors by eye while performing the surgery. The ability to see maximal tumors has been prioritized and this has led to the use of fluorophores activated by near-infrared (NIR) light as NIR penetrates most deeply in this surgical setting, but the light emitted by traditional NIR fluorophores is invisible to the naked eye. This has necessitated the use of specialty detectors and monitors that the surgeon must consult while performing the surgery. In this study, we develop nanoparticles that selectively label ovarian tumors and are activated by NIR light but emit visible light. This potentially allows for maximal tumor observation and real-time detection by eye during surgery. We designed two generations of up-converting nanoparticles that emit green light when illuminated with NIR light. These particles specifically label ovarian tumors most likely via tumor-associated macrophages, which are prominent in the tumor microenvironment. Our results demonstrate that this approach is a viable means of visualizing tumors during surgery without the need for complicated, expensive, and bulky detection equipment. Continued improvement and experimentation could expand our approach into a much needed surgical technique to aid ovarian tumor removal
A Double-Blind, RCT Testing Beneficial Modulation of BDNF in Middle-Aged, Life Style-Stressed Subjects: A Clue to Brain Protection?
Introduction: The aim of this prospective study was to see
whether LD-1227, a quality-controlled marine nutraceuticals
shown to protect experimental stress-induced hyppocampal
degeneration, could beneficially modulate BDNF, as measured in
the serum, in otherwise healthy but work-stressed individuals.
Materials and Methods: Forty-eight men and women between
the ages of 38 and 62 reporting high-demanding work activity
but with an overall positive attitude towards their personal life
were recruited. Subjects were divided in two group (24 patients
each) and blindly supplemented for 2 month with: a) LD-1227
400mg or b) placebo. A third group of healthy non-stressed
subjects was used as well. Blood samples were taken before
and after the supplementation period. Unstimulated saliva
was collected and tested for amylase while serum levels were
used to measure BDNF. State Trait Anxiety Inventory (STAI),
Pittsburgh Sleep Quality Index (PSQI) and psychological wellbeing assessment (PSWB) were measured too. Patients with
Val66Met functional polymorphism of BDNF excluded those
given their reported association with an impaired release of
BDNF.
Results: Results showed that, as compared to healthy, nonstressed individuals, stressed ones has a trend decrease
of BDNF and this was significantly increased by LD 12-1227
supplementation and the same inverse phenomenon occurred
to salivary amylase (p<0.05). No change was noted in the PSQI
score but, either STAI or PSWB tests scored better in LD-1227
supplemented subjects.
Conclusion: The present data suggest that LD-1227 is beneficially affecting neuromodulation and related symptoms during
common stressful life conditions and may have the potential as
tools in a neuroprotective clinical strategy
International Delegations and the Values of Federalism
Inland water sediments receive large quantities of terrestrial organic matter(1-5) and are globally important sites for organic carbon preservation(5,6). Sediment organic matter mineralization is positively related to temperature across a wide range of high-latitude ecosystems(6-10), but the situation in the tropics remains unclear. Here we assessed temperature effects on the biological production of CO2 and CH4 in anaerobic sediments of tropical lakes in the Amazon and boreal lakes in Sweden. On the basis of conservative regional warming projections until 2100 (ref. 11), we estimate that sediment CO2 and CH4 production will increase 9-61% above present rates. Combining the CO2 and CH4 as CO2 equivalents (CO(2)eq; ref. 11), the predicted increase is 2.4-4.5 times higher in tropical than boreal sediments. Although the estimated lake area in low latitudes is 3.2 times smaller than that of the boreal zone, we estimate that the increase in gas production from tropical lake sediments would be on average 2.4 times higher for CO2 and 2.8 times higher for CH4. The exponential temperature response of organic matter mineralization, coupled with higher increases in the proportion of CH4 relative to CO2 on warming, suggests that the production of greenhouse gases in tropical sediments will increase substantially. This represents a potential large-scale positive feedback to climate change
A randomized, controlled trial on the effectiveness of a proprietary marine lipo-peptide formula vs omega-3 on cytokines profile, anxiety, and pain symptoms in patients with fibromyalgia
Objective: The aim of the present study in an RCT manner (physicians and patients) a novel lipo-peptide marine compound, LD-1227, on physical-, emotional- and functional-related symptomatic complaints in fibromyalgia patients as well as inflammatory cytokines profile and gene expression while using omega-3 as a control group. Methods: The following questionnaire-based or clinical evaluation-based parameters were evaluated: widespread pain index [WPI] patient global impression of change, total tender points [TTP], fibromyalgia impact questionnaire, Beck depression inventory, fatigue severity ratings, cognitive symptom severity, symptom severity score [SSS] and weekly pain intensity ratings. Additional biochemical and gene expression analysis of cytokines (IL6, TNF-α, IL-1β, MCP-1, IL-8, IL-13, IL-1α, and GM-CSF) was performed as well. Data were analyzed with either a paired t-test or the Wilcoxon signed rank test depending on the parametric or non-parametric distribution. Results: Comparing the data from before and after treatment for Group B indicated a statistically significant reduction (p=0.05) in TTP, WPI score, and SSS score. These data suggest a positive effect of a 3-month treatment with the LD-1227 but not omega-3 treatment on Fibromyalgia pain and related anxiety/depressive symptoms. Inspections of HRV and Cytokines found a statistically significant improvement after LD1227 treatment. Unlike the group supplemented with omega-3, the treatment with LD-1227 brought about a decrease in WPI and weekly pain intensity symptoms for the majority of participants. The pre-and post-treatment data for Group B indicated a statistically significant reduction (p=0.05) in TPC, WPI, and SSS scores. No adverse events were reported. Conclusion: These results provide the first indications that the LD-1227 treatment has a statistically significant effect on the recognized fibromyalgia diagnosis metrics of WPI, TTP, and SSS as well on inflammatory markers and parasympathetic balance
Dissipative quantum mechanics and Kondo-like impurities on noncommutative two-tori
In a recent paper, by exploiting the notion of Morita equivalence for field
theories on noncommutative tori and choosing rational values of the
noncommutativity parameter (in appropriate units), a general
one-to-one correspondence between the -reduced conformal field theory (CFT)
describing a quantum Hall fluid (QHF) at paired states fillings and an Abelian noncommutative field theory (NCFT) has been
established . That allowed us to add new evidence to the relationship between
noncommutativity and quantum Hall fluids\cite% {ncmanybody}. On the other hand,
the -reduced CFT is equivalent to a system of two massless scalar bosons
with a magnetic boundary interaction as introduced by Callan et al., at the so
called ``magic''\ points. We are then able to describe, within such a
framework, the dissipative quantum mechanics of a particle confined to a plane
and subject to an external magnetic field normal to it. Here we develop such a
point of view by focusing on the case which corresponds to a quantum Hall
bilayer. The key role of a localized impurity which couples the two layers is
emphasized and the effect of noncommutativity in terms of generalized magnetic
translations (GMT) is fully exploited. As a result, general GMT operators are
introduced, in the form of a tensor product, which act on the QHF and defect
space respectively, and a comprehensive study of their rich structure is
performed.Comment: 18 pages, 1 figure, accepted for publication in International Journal
of Modern Physics
Trypanosoma amblyommi sp. nov. (Protozoa: Kinetoplastida) isolated from Amblyomma brasiliense (Acari: Ixodidae) ticks in Rio de Janeiro, Brazil.
Parasites of the genus Trypanosoma are microorganisms that display wide morphological, biological and genetic variability. Here we present the first description of an isolate of the genus Trypanosoma naturally infecting the tick Amblyomma brasiliense. The ticks were collected from a specimen of Tayassu pecari (Queixada, white-lipped peccary) from the Itatiaia National Park, Itatiaia, Rio de Janeiro, Brazil. The isolate was characterised by molecular, morphometric and biological analyses. A Trypanosoma culture was isolated from crushed nymphal and adult ticks, propagated in the tick cell line IDE8 and maintained in L15B culture medium, incubated at 32 °C. The isolate grew well in L15B medium at 30 °C, 32 °C and 34 °C but not at lower or higher temperatures. The culture remained stable in axenic L15B medium at 30 °C. Cryopreserved cultures retained viability after cryopreservation in liquid nitrogen. Growth in axenic medium and developmental forms of the trypanosomes were analysed. Analysis of the 18S rDNA region confirmed the authenticity of this new species and the nucleotide sequence was deposited in Genbank. The species was named Trypanosoma amblyommi sp. nov. strain C1RJ. Characteristics related to pathogenicity, involvement with vertebrate hosts, epidemiology, developmental cycle and transmission mechanisms are still unknown. Therefore, further studies are necessary to understand aspects of the biological cycle of Trypanosoma amblyommi sp. nov
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