Virtual brain endocast of Antifer (Mammalia: Cervidae), an extinct large cervid from South America

A diverse fossil record of Cervidae (Mammalia) has been documented in the South American Pleistocene, when these animals arrived during the Great American Biotic Interchange. Using computed tomography-scanning techniques, it is possible to access the endocranial morphology of extinct species. Here, we studied the brain endocast of the extinct late Pleistocene cervid Antifer ensenadensis from southern Brazil, one of the largest forms that lived on this continent, using comparative morphology, geometric morphometrics, and encephalization quotients. The analyzed endocasts demonstrate that A. ensenadensis had a gyrencephalic brain, showing a prominent longitudinal sinus (=sagittal superior sinus), which is also observed in the large South American cervid Blastocerus dichotomus. The encephalization quotient is within the variation of extant cervids, suggesting maintenance of the pattern of encephalization from at least the late Pleistocene. Geometric morphometric analysis suggested a clear and linear allometric trend between brain endocast size and shape, and highlights A. ensenadensis as an extreme form within the analyzed cervids regarding brain morphology.     

The incidence, distribution and expression of Australian grapevine yellows, restricted growth and late season leaf curl diseases in selected Australian vineyards

Surveys were conducted in four Chardonnay vineyards for 3 to 6 years and one Shiraz vineyard for 3 years to determine the yearly percentage of grapevines affected by Australian grapevine yellows disease (AGYd), restricted growth disease (RGd) and late season leaf curl disease (LSLCd). In each of the Chardonnay vineyards in each year, all three diseases were characterised by remission of disease in some grapevines, recurrence of disease in other grapevines and new observations of disease in previously unaffected grapevines. The pattern of temporal incidence of each disease was different between vineyards for the survey period. Although Koch's postulates have not been fulfilled, phytoplasmas are considered to be the most likely cause of AGYd. While some grapevines exhibited a combination of AGYd and RGd or AGYd and LSLCd, both RGd and LSLCd can occur independently of AGYd. Statistical analyses using log-linear models also indicated that RGd and LSLCd were not always associated with AGYd. Thus, it is possible that phytoplasmas are not the cause of RGd or LSLCd and their association is coincidental. Expression of AGYd in Shiraz grapevines occurred later in the season compared to Chardonnay. Very little recurrence of AGYd was observed in the Shiraz grapevines indicating that the variety Shiraz responds differently to phytoplasma infections, assuming that AGYd in Shiraz is a phytoplasma caused disease. RGd and LSLCd were not observed on any grapevines in the Shiraz vineyard.     

A novel trophic relationship between cassid gastropods and mysticete whale carcasses

Large cassid gastropods found in close association with Oligocene mysticete whale skeletons in a deep water setting indicate a novel trophic relationship. Bones of early mysticetes are preserved in close association with a recurring assemblage of bivalve taxa that are common components of fossil and recent hydrothermal vent and cold methane seep localities. Living members of these bivalve groups harbor sulfide-oxidizing autotrophic bacteria and comparisons with recent whale-falls indicate that they utilized bone-oil seepage. But unlike recent whale-falls, this fossil invertebrate assemblage is volumetrically dominated by large individuals of the cassid gastropod Liracassis apta that are preserved with their apertures adhering to the bone surfaces. Comparisons with recent cassoidean taxa and their ecological settings suggests that Liracassis apta belongs to the subfamily Oocorythinae, not Cassininae, and was an opportunistic scavenger in deep water, low oxygen environments. Oocorythine gastropods radiated rapidly on the northeastern Pacific margin during the Late Eocene and Oligocene to become the most commonly recorded gastropod in shelf and slope settings.     

DISTYLOMYIDAE FAM. NOV. (?CTENODACTYLOIDEA, RODENTIA) FROM NEI MONGOL, CHINA

<正> IntroductionA pair of rodent lower jaws believed belonging to one and the same individual were collected by the present author from Upper Oligocene Yikebulage Formation in Qianlishan district,Ih Ju League(=Yih Ju Meng),Nei Mongol,in 1978 The affinity searching of the lower jaws has really been a brain-racking one. At first glance I was struck by the similarity between     

内蒙阿左旗乌兰塔塔尔中渐新世的梳趾鼠类

本文描述和比较了发现在我国内蒙古阿左旗乌兰塔塔尔地区中渐新统的三属七种啮齿类梳趾鼠科化石,其中包括三个新种.并对某些种类的归属和性质做了初步的讨论.     

记内蒙古Juxia一新种

本文记述了在内蒙古沙拉木伦额尔登敖包地区第三系下渐新统乌兰戈楚组中发现的始巨犀的一个新种:寿氏始巨犀(Juxia shoui)。据其前臼齿及鼻切迹的位置等特点,这一新种当为始巨犀属中比较进步的一个成员,是包氏始巨犀和巨犀之间的过渡类型的犀类动物。     

Chromosomal heteromorphism linked to the mating type locus of the oomycetePhytophthora infestans

The mating type locus of the oomycete,Phytophthora infestans, is embedded in a region of DNA that displays distorted and non-Mendelian segregation. By using DNA probes linked to the mating type locus to genetically and physically characterize that region, a large zone of chromosomal heteromorphism was detected. LocusS1 was shown to represent a tandemly repeated array of DNA that was typically present in a hemizygous state in A1 isolates while being absent from A2 isolates. The analysis of the parents and progeny of seven crosses indicated that the tandem array was linked in cis to the A1-determining allele of the mating type locus. A worldwide survey of genotypically diverse field isolates ofP. infestans indicated thatS1 was present in each of 48 isolates of the A1 mating type that were tested, but was absent in 46 of 47 A2 strains. Physical analysis ofS1 indicated that the tandemly repeated DNA sequence spanned about 300 kb and had evolved from a 1.35-kb monomer. Internal deletions occurred withinS1 during sexual propagation. This and other mutations apparently contributed to a high degree of polymorphism within theS1 array.     

Optimization of biolistic method for transient gene expression and production of agronomically useful transgenic Basmati rice plants

We have developed a reproducible biolistic procedure for the efficient transformation of embryogenic suspension cells of an improved aromatic Indica rice variety, Pusa Basmati 1. The -glucuronidase gene was used to assay transient transformation; other plasmids carrying either a potato protease inhibitor 2 (Pin2) gene, or a late embryogenesis-abundant protein (LEA3) gene from barley, were used for the optimization of biolistic process and transgenic plant production. After optimization of the procedure, over 600 transient transformants and at least five fertile plants showing integrative transformation were obtained per bombarded filter. At least 30% of the plants were derived from independent transformation events. The new improved procedure involves the use of a reporter gene or other useful genes driven by the strong rice actin 1 gene (Act1) promoter, osmotic pre-conditioning of cells for 24 h on medium supplemented with 0.25 M mannitol prior to bombardment, use of gold particles for DNA delivery, and use of plant regeneration medium with high (1.0%) agarose concentration.     

Carbon isotope fractionation in tree ring early and late wood in relation to intra-growing season water balance

We determined the stable carbon isotope composition (δ^1.3C) of cellulose extracted from early and late wood in Douglas fir [Pseudotsuga menziexii (Mirb.) Franco] tree rings. Data were obtained for the period 1962 to 1981, at the start of which the trees were 20 years old. A water balance model was used to calculate daily stand transpiration and water deficit. The model incorporates site factors (soil water availability, slope and aspect) and environmental variables (solar radiation, air temperature and rainfall). There was far greater variability in late wood than in early wood δ^1.3C. In wet years, late wood δ^1.3C was significantly lighter (by as much as 2δ) than early wood δ^1.3C but in dry years this difference was reversed. Differences between spring and summer cumulative transpiration accounted for almost 60δ of the variability in differences between early and late wood δ^1.3C. We found excellent correspondence between summer cumulative transpiration and late wood δ^1.3C, with estimates of transpiration accounting for up to 93% of the variability in δ^1.3C. Correlations between early wood δ^1.3C and spring transpiration were generally poor (r2<0.4), but we were able to identify those exceptional years in which there had been a very dry spring. Our results indicate that, while tree ring δ^1.3C correlates reasonably well with basal area increment, it is a far better indicator of inter- and intra-annual variability in water availability than radial growth.