Flooded flatheads: evidence of increased growth in Mississippi River <Emphasis Type="Italic">Pylodictis olivaris</Emphasis> (Pisces: Ictaluridae) following the Great Midwest Flood of 1993

Both the Mississippi and Missouri rivers experienced major flooding in the spring and summer of 1993, inundating much of their floodplains for long periods, and allowing fish access to vast but previously inaccessible benthic foraging areas. In response to the latter, we hypothesized that flathead catfish (Pylodictis olivaris) would exhibit altered post-flooding growth as compared to like-aged fish whose lives were flood-free. To test this hypothesis, we obtained the left pectoral fin spines from hoop-netted Mississippi River flathead catfish collected in the vicinity of Crystal City, Missouri, USA, and conducted an individual-based back-calculated growth comparison of individuals captured pre-flood (1991) and post-flood (1996). For like-aged cohorts, our back-calculated length-at-age data clearly show that the post-flooding growth in 1996-collected fish was superior to that of the 1991-collected fish that had experienced less exceptional flow regimes. This outcome suggests that increased forage or/and foraging opportunities can be a consequence of flooding, and that flathead catfish are able to capitalize on this. The natural flooding regime of big rivers may thus be an important contributor to the growth and success of certain fish species; consequently, modifying the river’s natural hydrograph and channel morphology may be detrimental. Handling editor: J. A. Cambray An erratum to this article is available at .     

A new species of the clingfish genus <Emphasis Type="Italic">Apletodon</Emphasis> (Teleostei: Gobiesocidae) from Sao Tome and Principe,Eastern Central Atlantic

The clingfish Apletodon wirtzi sp. nov. is described on the basis of ten specimens and colour photos from Bombom Island, Principe Group, Sao Tome and Principe, eastern central Atlantic Ocean. The species is very small, apparently not exceeding 16 mm total length; it is characterized by having three pores in the mandibular canal, the head length 2.2–2.5 in standard length: SL, the head broad, head width in males 3.6–4.0 (mean 3.8) in SL, the snout in males long, more or less pointed, conical, preorbital length in males 3.1–4.0 in head length, the occipital region with a large pinkish blotch behind each eye (in alcohol specimens), and the lower sides of the body with a row of dark blotches, scattered with white spots in between. The new species is compared with other species of the genus; a key to the males of the four known species of the eastern Atlantic genus Apletodon is presented. Supplementary material to this paper is available in electronic format at     

Evaluation of novel beta-lactam antibiotics in comparison to cefotaxime on plant regeneration of <Emphasis Type="Italic">Citrus sinensis</Emphasis> L. Osb.

Identification of beta-lactam antibiotics that have negligible effects on plant regeneration is a critical step towards the establishment of a reliable Agrobacterium-mediated transformation protocol for perennial trees. In the present report, we have evaluated the effects of the novel beta-lactam antibiotics meropenem and timentin on plant regeneration of a perennial woody fruit plant, Citrus sinensis, in comparison with the commonly used beta-lactam cefotaxime. It was observed that, in contrast to cefotaxime, meropenem and timentin had a positive or no detrimental effect on the shoot regeneration from epicotyl explants. Residual effects of the beta-lactams from shoot regeneration medium also affected the subsequent ability of the roots to elongate. The addition of meropenem and/or timentin in the rooting medium mostly improved or did not affect the rooting ability of the adventitious shoots. These data indicated that meropenem and timentin can positively replace cefotaxime in Agrobacterium-mediated transformation of C. sinensis.     

Xplor® 2—an optimized transformation/expression system for recombinant protein production in the yeast <Emphasis Type="Italic">Arxula adeninivorans</Emphasis>

Combining ease of genetic manipulation and fermentation with the ability to secrete and to glycosylate proteins in the basic eukaryotic manner, Arxula adeninivorans provides an attractive expression platform. Based on a redesign of the basic vector, a new Arxula vector system, Xplor® 2, for heterologous gene expression was established, which allows (1) the construction of expression plasmids for supertransformation of A. adeninivorans strains secreting target proteins of biotechnological interest and (2) the integration of small vector cassettes consisting of yeast DNA sequences only. For this purpose, a set of modules including the ATRP1m selection-marker module, expression modules for constitutive expression of the genes phyK (Klebsiella-derived phytase) and IFNα2a (human interferon α), the HARS (Hansenula polymorpha autonomous replication sequence) for autonomous replication and the chaperone module AHSB4 promoter –HpCNE1 gene (calnexin) –PHO5 terminator to improve secretion efficiency were constructed and integrated in various combinations in the basic vector Xplor® 2. After removal of the complete Escherichia coli-based plasmid parts (resistance marker, ColE1 ori and f1(?) origin), the remaining yeast-based linear vector fragment with or without rDNA targeting sequences were transformed as yeast rDNA integrative expression cassettes and yeast integrative expression cassettes (YICs), respectively, and the resulting strains were tested for their capacity to secrete PhyK or IFNα2a. Maximal expression levels were consistently obtained using YICs for transformation irrespective of whether or not they carry HARS and/or calnexin modules. It is recommended that at least 50 such transformants be analyzed to ensure selection of the best transformants.     

Two new names in West-Central African <Emphasis Type="Italic">Quassia</Emphasis> L. (<Emphasis Type="Italic">Simaroubaceae</Emphasis>)

Summary  Two West-Central African species of Hannoa Planch. are formally resurrected in the genus Quassia L. and the necessary new names provided.     

Assessment of hybrid vigor between flightless lines to restore survival and reproductive characteristics in the ladybird beetle <Emphasis Type="Italic">Harmonia axyridis</Emphasis>

The effectiveness of hybrid vigor, which can counteract deleterious effects of inbreeding in flightless Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was investigated. First, we performed the reciprocal cross between two isofemale lines and compared survival and reproductive characteristics between isofemale and hybrid lines under laboratory conditions. The survival of one of the hybrid lines was significantly higher than that of the two isofemale lines. Early fecundity tended to be higher in the two hybrid lines than in the two isofemale lines. Second, we compared the effectiveness of control of Aphis gossypii Glover (Homoptera: Aphididae) between isofemale and hybrid lines by release experiments in greenhouses. The number of A. gossypii was suppressed in treatments in which two hybrid lines were released compared with those in which two isofemale lines were released. These results suggest that hybrid vigor is effective as a method for assuring the quality of flightless H. axyridis.     

Waste of leaf-cutting ants: disposal,nest structure,and abiotic soil factors around internal waste chambers

Leaf-cutting ants produce large quantities of waste that harbor bacteria and fungi that are harmful to the colony. To be protected from these pathogens, the workers of Atta species present a sophisticated organization to manage harmful material, which can be deposited outside the nest or in internal chambers. However, little is known about the behavior of Acromyrmex species in handling and disposal of waste. Due to some observations, we assume that the same species of Acromyrmex can deposit waste outside the nest and into internal chambers and raise the following question: what determines the occurrence of internal waste chambers in Acromyrmex? To address this question, we verified whether nest depth influences the waste-chamber occurrence. We also verified the nest structure and the abiotic factors of soil beside each waste-chamber: pH and water content of the soil. For this, eight nests were excavated for Acromyrmex balzani and Acromyrmex rugosus rugosus. We verified that not only can the same leaf-cutting ant species deposit debris both outside and inside the nest but also the same nest can present internal chambers and external waste deposit. The soil beside the waste chamber always presented an acidic pH, while the humidity varied widely. Our results showed that the nest depth was highly correlated with the depth of the waste chamber (p = 0.0003) and probably has some influence on waste disposal. The characteristics of the nest and the role of depth in the choice of waste chamber location are discussed.     

Large fluctuations but constant mean temperatures allow corals to persist in intertidal rock pools on the east coast of South Africa

Intertidal corals have been under-studied yet they provide scope for understanding adaptation and acclimatisation of corals to marginal conditions. Corals in intertidal rock pools along the east coast of South Africa withstand large temperature fluctuations, and marginal conditions for survival and growth. Four sites along the KwaZulu-Natal (KZN) coastline were sampled to determine latitudinal differences in coral communities, from 27°S to 31°S. Water temperature of rock pools at each site was monitored to see if temperature determined coral diversity in intertidal pools. Sixteen coral species were present in rock pools overall. Each of three sites in northern and central KZN hosted 12 coral taxa whereas only six taxa occurred at the most southern site. Anomastrea irregularis was the most abundant species at all sites, followed by Pocillopora verrucosa and P. damicornis. Unexpectedly, rock pool temperatures did not show a trend with latitude and thus cannot explain this decline in coral diversity. Temperatures in isolated rock pools showed large summer day time fluctuations of more than 10 °C at spring tide. However, temperatures drop substantially at high tide, lowering the mean rock pool temperature and possibly allowing these coral communities to persist in the marginal conditions of rock pools in South Africa.