Seminal and endocrine characteristics of male Pallas' Cats (Otocolobus manul) maintained under artificial lighting with simulated natural photoperiods

Pallas' cats (Otocolobus manul) have a pronounced reproductive seasonality controlled by photoperiod. Previous studies of reproduction in captive Pallas' cats exposed to natural light showed a breeding season of December–April. This study evaluated the impact of artificial lighting timed to simulate natural photoperiods on male reproductive seasonality of four Pallas' cats housed indoors. Semen evaluation, blood collection, and body weight measurements were conducted every 1–2 months from November 2000–June 2001. Fecal samples were collected from each male twice weekly to assess testosterone and corticoid concentrations. Mean values for reproductive traits (sperm attributes, testicular volume) were highest from February–April, the defined breeding season. Fecal testosterone concentrations were highest from mid‐January to mid‐March. Male Pallas' cats managed indoors under simulated photoperiods experienced a delayed onset of the breeding season by 1–2 months and a decreased length of the breeding season. Over the course of the study, fecal corticoid concentrations did not seem to differ among seasons. Although mating attempts during this study were unsuccessful, subsequent pairings of male and female Pallas' cats in the same research colony during the 2002 and 2003 breeding seasons produced viable offspring. These results suggest that male Pallas' cats, housed indoors under simulated photoperiods, exhibit distinct reproductive cyclic patterns, characterized by a delayed and truncated breeding season. Adrenocortical activity varied among individuals, but did not adversely affect reproductive parameters. Housing Pallas' cats indoors under simulated photoperiods may represent a viable strategy for maintaining breeding success while limiting disease exposure. Zoo Biol 0:1–13, 2007. © 2007 Wiley‐Liss, Inc.     

Dynamic light scattering and fluorescence study of the interaction between double-stranded DNA and poly(amido amine) dendrimers

The interaction between a cationic poly(amido amine) (PAMAM) dendrimer of generation 4 and double-stranded salmon sperm DNA in 10 mM NaBr solution has been investigated using dynamic light scattering (DLS) and steady-state fluorescence spectroscopy. The structural parameters of the formed aggregates as well as the complex formation process were studied in dilute solutions. When DNA is mixed with PAMAM dendrimers, it undergoes a transition from a semiflexible coil to a more compact conformation due to the electrostatic interaction present between the cationic dendrimer and the anionic polyelectrolyte. The DLS results reveal that one salmon sperm DNA molecule forms a discrete aggregate in dilute solution with several PAMAM dendrimers with a mean apparent hydrodynamic radius of 50 nm. These discrete complexes coexist with free DNA at low molar ratios of dendrimer to DNA, which shows that cooperativity is present in the complex formation. The formation of the complexes was confirmed by agarose gel electrophoresis measurements. DNA in the complexes was also found to be significantly more protected against DNase catalyzed digestion compared to free DNA. The number of dendrimers per DNA chain in the complexes was found to be approximately 35 as determined by steady-state fluorescence spectroscopy.     

The HIV-1 Rev response element (RRE) adopts alternative conformations that promote different rates of virus replication

The HIV Rev protein forms a complex with a 351 nucleotide sequence present in unspliced and incompletely spliced human immunodeficiency virus (HIV) mRNAs, the Rev response element (RRE), to recruit the cellular nuclear export receptor Crm1 and Ran-GTP. This complex facilitates nucleo-cytoplasmic export of these mRNAs. The precise secondary structure of the HIV-1 RRE has been controversial, since studies have reported alternative structures comprising either four or five stem-loops. The published structures differ only in regions that lie outside of the primary Rev binding site. Using in-gel SHAPE, we have now determined that the wt NL4-3 RRE exists as a mixture of both structures. To assess functional differences between these RRE ‘conformers’, we created conformationally locked mutants by site-directed mutagenesis. Using subgenomic reporters, as well as HIV replication assays, we demonstrate that the five stem-loop form of the RRE promotes greater functional Rev/RRE activity compared to the four stem-loop counterpart.     

A novel series of IKKβ inhibitors part II: description of a potent and pharmacologically active series of analogs

A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKβ. In this Letter we document our efforts at further optimization of this series, culminating in 2 with submicromolar potency in a HWB assay and efficacy in a CIA mouse model.     

Cardiovascular events in early RA are a result of inflammatory burden and traditional risk factors: a five year prospective study

Introduction  

Co-morbidity and mortality due to cardiovascular disease (CVD) are increased in patients with rheumatoid arthritis (RA). Most published studies in this field are retrospective or cross sectional. We investigated the presence of traditional and disease related risk factors for CVD at the onset of RA and during the first five years following diagnosis. We also evaluated their potential for predicting a new cardiovascular event (CVE) during the five-year follow-up period and the modulatory effect of pharmacological treatment.     

Phylogenetic distribution of intron positions in alpha-amylase genes of bilateria suggests numerous gains and losses

Most eukaryotes have at least some genes interrupted by introns. While it is well accepted that introns were already present at moderate density in the last eukaryote common ancestor, the conspicuous diversity of intron density among genomes suggests a complex evolutionary history, with marked differences between phyla. The question of the rates of intron gains and loss in the course of evolution and factors influencing them remains controversial. We have investigated a single gene family, alpha-amylase, in 55 species covering a variety of animal phyla. Comparison of intron positions across phyla suggests a complex history, with a likely ancestral intronless gene undergoing frequent intron loss and gain, leading to extant intron/exon structures that are highly variable, even among species from the same phylum. Because introns are known to play no regulatory role in this gene and there is no alternative splicing, the structural differences may be interpreted more easily: intron positions, sizes, losses or gains may be more likely related to factors linked to splicing mechanisms and requirements, and to recognition of introns and exons, or to more extrinsic factors, such as life cycle and population size. We have shown that intron losses outnumbered gains in recent periods, but that "resets" of intron positions occurred at the origin of several phyla, including vertebrates. Rates of gain and loss appear to be positively correlated. No phase preference was found. We also found evidence for parallel gains and for intron sliding. Presence of introns at given positions was correlated to a strong protosplice consensus sequence AG/G, which was much weaker in the absence of intron. In contrast, recent intron insertions were not associated with a specific sequence. In animal Amy genes, population size and generation time seem to have played only minor roles in shaping gene structures.     

The hydrology of Lake Victoria

Summary Evidence is presented to show that Lake Victoria is triply stratified the whole year round. The conclusions of FISH (1957) that a uninodal internal seiche operates in the lake is shown to be invalid, and the oscillations of isotherms at E.A.F.R.O. Open Lake Station observed over some years are explained by the day to day wind changes.It is calculated that an internal seiche could operate between the middle and bottom layers, but not between the middle and surface layers, since any such seiche would break down the stratification. Surface waves of the type which normally induce internal seiches are commonly observed on the lake, so it is concluded that the extreme shallowness and great length of Lake Victoria cause a rapid frictional damping of any incipient seiche.Lake Victoria has an annual heat budget of about 9,000 gram/cals/cm². This amount of heat is lost between March and August and regained between August and March. The loss of heat is occasioned mainly by the increase in evaporation from the lake in the period May to October, and partly by an increase in conduction and backradiation. The increase in evaporation rate between May and October assists in disposing of the surplus water derived from the rains in April.The lowest layer in the lake is believed to derive from the inflow of rivers. This layer mixes with the middle layer at the south end of the lake. An apparent area of mixing is suggested north of the Sesse Islands, also.Current measurements indicate a general northward flow of surface water in response to the wind. This is accompanied by a compensating flow of the two lower layers southwards. This latter movement is mainly phasic but probably has a small residual component.Lake level readings from gauges round the lake indicate that the west, north and north-east portions of the lake rise more rapidly in level than the south portion, from April to July.

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Résumé Cette étude montre une stratification permanente du Lac Victoria en trois couches. Elle tend à montrer que la conclusion à l'existence d'une seiche interne uninodale (Fish, 1957) n'est pas valable, et que les oscillations des isotherms observés sont dues au changement du régime des vents d'un jour à l'autre.Le calcul prouve qu'il est possible qu'une seiche interne agisse entre la couche profonde et la couche moyenne, mais certainement pas entre la couche moyenne et la surface, puis-qu' alors elle detruivrait la stratification.Des vagues du type qui normallement provoque les seiches sont couramment observées sur le Lac Victoria. L'Auteur en conclut que la tres faible profondeur et la forme allongée de ce lac causerait un rapide amortissement par friction d'une éventuelle seiche.Le Lac Victoria a un bilan calorifique annuel de 9,000 g/cal/cm². Cette quantité de chaleur est perdue entre mars et août. La perte de chaleur est essentiellement due à l'augmentation d'évaporation de mai à octobre et partiellement à une augmentation de conduction et de radiation. L'accroissement du taux d'évaporation de mai à octobre contribue à eliminer le surplus d eau provenant des précipitations d'avril.Les causes les plus profondes proviendraient de l'apport des rivières. Les couches profondes et moyennes se mêlent a l'extrémité Sud du lac. Il semble aussi que le mélange se fasse au Nord des îles Sesse.Le vent provoque en surface un courant dirigé vers le Nord, compensé par un deplacement vers le Sud des deux couches inférieurs. Ce deplacement est surtout periodique mais à aussi une l égère composante résiduelle.Des relevés de niveau tout autour du lac montrent que d'avril à juillet celui-ci s'élève plus rapidement à l'Ouest, au Nord et au Nord-Est qu'au Sud.