Cysteine-rich secretory protein 2 binds to mitogen-activated protein kinase kinase kinase 11 in mouse sperm

Cysteine-rich secretory protein (CRISP) 2 (previously TPX1) is a testis-enriched member of the CRISP family, and has been localized to both the sperm acrosome and tail. Like all members of the mammalian CRISP family, its expression pattern is strongly suggestive of a role in male fertility, but functional support for this hypothesis remains limited. In order to determine the biochemical pathways within which CRISP2 is a component, the putative mature form of CRISP2 was used as bait in a yeast two-hybrid screen of a mouse testis expression library. One of the most frequently identified interacting partners was mitogen-activated protein kinase kinase kinase 11 (MAP3K11). Sequencing and deletion experiments showed that the carboxyl-most 20 amino acids of MAP3K11 interacted with the CRISP domain of CRISP2. This interaction was confirmed using pull-down experiments and the cellular context was supported by the localization of CRISP2 and MAP3K11 to the acrosome of the developing spermatids and epididymal spermatozoa. Interestingly, mouse epididymal sperm contained an approximately 60-kDa variant of MAP3K11, which may have been a result of proteolytic cleavage of the longer 93-kDa form seen in many tissues. These data raise the possibility that CRISP2 is a MAP3K11-modifying protein or, alternatively, that MAP3K11 acts to phosphorylate CRISP2 during acrosome development.     

Studying alternative splicing regulatory networks through partial correlation analysis

Background  

Alternative pre-mRNA splicing is an important gene regulation mechanism for expanding proteomic diversity in higher eukaryotes. Each splicing regulator can potentially influence a large group of alternative exons. Meanwhile, each alternative exon is controlled by multiple splicing regulators. The rapid accumulation of high-throughput data provides us with a unique opportunity to study the complicated alternative splicing regulatory network.     

Flowering pathway is regulated by bulb size in Lilium longiflorum (Easter lily)

Lilium longiflorum (Easter lily) vegetative propagation occurs through production of underground bulbs containing apical and axillary meristems. In addition, sexual reproduction is achieved by flowering of elongated shoots above the bulb. It is generally accepted that L. longiflorum has an obligatory requirement for vernalisation and that long day (LD) regime hastens flowering. However, the effect of bulb size and origin, with respect to axillary or apical meristems on flowering, as well as the interactions between these meristems are largely unknown. The aim of this study was to explore the effect of bulb size, vernalisation and photoperiod on L. longiflorum flowering. To this end, we applied vernalisation and photoperiod treatments to the different bulb sizes and used a system of constant ambient temperature of 25 °C, above vernalisation spectrum, to avoid cold‐dependent floral induction during plant growth. Vernalisation and LD hasten flowering in all bulbs. Large, non‐vernalised bulbs invariably remained at a vegetative stage. However, small non‐vernalised bulbs flowered under LD conditions. These results demonstrate for the first time that cold exposure is not an obligatory prerequisite for L. longiflorum flowering, and that an alternative flowering pathway can bypass vernalisation in small bulbs. We suggest that apical dominance interactions determine the distinct flowering pathways of the apical and axillary meristems. Similar floral induction is achieved in propagated bulblets from scaling. These innovative findings in the field of geophyte floral induction represent valuable applicative knowledge for lily production.     

Predicting alpha diversity of African rain forests: models based on climate and satellite‐derived data do not perform better than a purely spatial model

Aim Our aim was to evaluate the extent to which we can predict and map tree alpha diversity across broad spatial scales either by using climate and remote sensing data or by exploiting spatial autocorrelation patterns. Location Tropical rain forest, West Africa and Atlantic Central Africa. Methods Alpha diversity estimates were compiled for trees with diameter at breast height ≥ 10 cm in 573 inventory plots. Linear regression (ordinary least squares, OLS) and random forest (RF) statistical techniques were used to project alpha diversity estimates at unsampled locations using climate data and remote sensing data [Moderate Resolution Imaging Spectroradiometer (MODIS), normalized difference vegetation index (NDVI), Quick Scatterometer (QSCAT), tree cover, elevation]. The prediction reliabilities of OLS and RF models were evaluated using a novel approach and compared to that of a kriging model based on geographic location alone. Results The predictive power of the kriging model was comparable to that of OLS and RF models based on climatic and remote sensing data. The three models provided congruent predictions of alpha diversity in well‐sampled areas but not in poorly inventoried locations. The reliability of the predictions of all three models declined markedly with distance from points with inventory data, becoming very low at distances > 50 km. According to inventory data, Atlantic Central African forests display a higher mean alpha diversity than do West African forests. Main conclusions The lower tree alpha diversity in West Africa than in Atlantic Central Africa may reflect a richer regional species pool in the latter. Our results emphasize and illustrate the need to test model predictions in a spatially explicit manner. Good OLS or RF model predictions from inventory data at short distance largely result from the strong spatial autocorrelation displayed by both the alpha diversity and the predictive variables rather than necessarily from causal relationships. Our results suggest that alpha diversity is driven by history rather than by the contemporary environment. Given the low predictive power of models, we call for a major effort to broaden the geographical extent and intensity of forest assessments to expand our knowledge of African rain forest diversity.     

Un difficile problème de taxonomie : les Micrasema (Trichoptera : Brachycentridae) des eaux courantes de la Péninsule Ibérique et des Pyrénées

Un des problèmes taxonomiques les plus compliqués concernant les Trichoptères européens est celui de la plupart des espèces ibériques et pyrénéennes du genre Micrasema, habitants caractéristiques du Rhitral, ces espèces restant à ce jour imparfaitement connues et difficiles à déterminer. L´étude d’un grand nombre d´exemplaires (mâles) a permis de trouver une solution pour la plupart des problèmes. M. servatum (Navás 1918), distribuée dans les parties N.O. de la Péninsule; M. cenerentola Schmid 1952, connue du Centre et du N.O. de l´Espagne; et M. salardum Schmid 1952, connue des Pyrénées Orientales espagnoles, sont des espèces distinctes. M. gabusi Schmid 1952 décrite de la Sierra Nevada, est un synonyme de M. longulum McLachlan 1876, une espèce largement distribuée en Espagne. M. difficile Mosely 1933, décrite des Pyrénées françaises, est un synonyme de M. vestitum Navás 1918, espèce endémique des Pyrénées Centrales et Occidentales (France et Espagne). L´identité de M. moestum (Hagen 1868) pose un problème particulier : il est possible que sous ce nom on désigne actuellement une paire d´espèces cryptiques à l´état adulte, qu´il est pratiquement impossible de distinguer par leurs genitalia, mais dont les larves sont bien distinctes.