Food dependent color patterns inThamnocephalus platyurus Packard (Branchiopoda: Anostraca); a laboratory study

Coloration of phyllopods varies from place to place and from one life stage to another. It ranges from translucent or whitish through gray, blue, green, orange, and reddish. Here, we present experimental evidence for a food- dependent color pattern inThamnocephalus platyurus Packard. The presence or absence of the synthetic pigment trans — — carotene in a baker's yeast diet was the controlling factor. All the 24 old larvae used in the experiment were whitish in color. From day 6 until the end the experiment (day 11), 100% of the shrimps under a diet with synthetic trans — — carotene (treatment 1) exhibited a characteristic color pattern which consisted of an orange color in the cercopods, and in all theracopods; the rest of the body exhibited no particular color. In comparison, 100% of the shrimps under a diet without synthetic trans — — carotene (treatment 2) were whitish throughout the body. In females from treatment 1, the ovaries and oocytes were green-bluish, while in females from treatment 2 the ovaries and oocytes were whitish. No significant differences in survival and growth were found, except that at day 9, there was a significant difference in growth, the females with the synthetic trans — — carotene group growing faster.     

New records of large branchiopods (Branchiopoda: Anostraca,Notostraca, and Spinicaudata) in Mexico

This paper reports new distribution records of large branchiopods for Mexico following a three year survey of the Baja California peninsula. The occurance of the anostracans Thamnocephalus mexicanus (Linder, 1941) and T. platyurus (Packard, 1877), the notostracan Lepidurus lemmoni (Holmes, 1894), and the spinicaudatans Eulimnadia cylindrova (Belk, 1989) and E. texana (Packard,1871), all represent the first records for the peninsula. An undescribed species of the anostracan genus Streptocephalus is recorded from the state of Baja California (Norte). The occurrence of the notostracan genus Triops and four other anostracan species on the peninsula is also confirmed. The conchostracan Cyclestheria hislopi (Baird, 1859) is recorded from the state of Quintana Roo. The collections of Lepidurus and Cyclestheria are the first records for México. These records increase the number of species of large branchiopods reported fromMéxico to 36: 20 Anostraca, 3 Notostraca, 11 Spinicaudata, and 2Laevicaudata. This revised version was published online in August 2006 with corrections to the Cover Date.     

Phosphoprotein Component of Vaccinia Virions

The recent discovery of a protein kinase activity in vaccinia virions led us to search for a viral protein which is phosphorylated in vivo. Vaccinia virus was radioactively labeled by infecting cells in the presence of (32)P(1). A phosphoprotein was isolated from purified delipidated virions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The phosphoprotein appeared to be a specific viral component induced after infection. More than 60% of the phosphoprotein was associated with viral cores. The electrophoretic mobility of the protein suggested that it has a molecular weight of 11,000 to 12,000. Phosphoserine was liberated by acid hydrolysis and identified by electrophoresis with known standards. Tryptic digests of the purified phosphoprotein were analyzed by two-dimensional electrophoresis and chromatography on thin-layer cellulose plates, and a single major phosphopeptide was resolved. The high selectivity of phosphorylation suggested that the process has a specific function.     

Large branchiopod assemblages common to Mexico and the United States

Cu, Cd, Zn and Pb concentrations in both dissolved andparticulate phase were assessed during 1995. DataQuality Assurance was an integral part of this studyand involved all major steps of the analysis proceduresuch as sampling, sample handling, preconcentrationand determination. Desorption and redox processes clearly control thedissolved Cu and Cd profiles. Mobilisation ofdissolved Zn is small and essentially restricted tothe low salinity area and the late spring survey.Dissolved Pb shows the clearest dilution pattern. Theparameters representative of these processes(dissolved oxygen and salinity) also correlate verywell with the particulate metal profiles. In addition, the plankton activity (expressed by thechlorophyll-a levels) may influence the dissolved andparticulate metal profiles. In combination withdesorption and redox processes, seasonal variationswere induced. This revised version was published online in July 2006 with corrections to the Cover Date.     

Multiple signals modulate the activity of the complex sensor kinase TodS

The reason for the existence of complex sensor kinases is little understood but thought to lie in the capacity to respond to multiple signals. The complex, seven‐domain sensor kinase TodS controls in concert with the TodT response regulator the expression of the toluene dioxygenase pathway in Pseudomonas putida F1 and DOT‐T1E. We have previously shown that some aromatic hydrocarbons stimulate TodS activity whereas others behave as antagonists. We show here that TodS responds in addition to the oxidative agent menadione. Menadione but no other oxidative agent tested inhibited TodS activity in vitro and reduced P_todX expression in vivo. The menadione signal is incorporated by a cysteine‐dependent mechanism. The mutation of the sole conserved cysteine of TodS (C320) rendered the protein insensitive to menadione. We evaluated the mutual opposing effects of toluene and menadione on TodS autophosphorylation. In the presence of toluene, menadione reduced TodS activity whereas toluene did not stimulate activity in the presence of menadione. It was shown by others that menadione increases expression of glucose metabolism genes. The opposing effects of menadione on glucose and toluene metabolism may be partially responsible for the interwoven regulation of both catabolic pathways. This work provides mechanistic detail on how complex sensor kinases integrate different types of signal molecules.     

Molecular characterization of the tadpole shrimp Triops (Branchiopoda: Notostraca) from the Baja California Peninsula,México: New insights on species diversity and phylogeny of the genus

Using sequence analyses of fragments of the small and large subunits of mitochondrial genes 12S and 16S rRNA, we studied the molecular identity of five Triops populations from the Baja California Peninsula, México. Additionally, we explored the phylogeny of the genus by comparing with sequence data from gonochoric T. longicaudatus (Zacatecas, México), commercial Triops kit (U.S.A.), T. `granarius' (Japan), T. cancriformis (Austria), T. australiensis (Australia) and Lepidurus lemmoni (U.S.A.). The 16S fragment was not useful to discriminate the American Triops forms because their sequences were more than 99% similar. Molecular and phylogenetic analyses using the 12S gene fragments, in agreement with previous allozyme studies, indicate that the nominal (morphological) species T. longicaudatus is a mixture of several species such that, of the seven Triops American populations studied, six phylogenetic species can be identified and two morphologically and reproductively highly divergent forms can be grouped into a single monophyletic clade. The molecular data, rather than supporting our previous proposal that the phylogenetic relationships of Triops species could be deduced by similarities in the number of total and legless rings, suggest that T. cancriformis may represent an independent group from the rest of the species in that genus. In spite of detectable differences among American populations, our analyses indicate these represent a single monophyletic group when compared to Triops from outside of the New World.     

Mixture of parthenogenetic and zygogenetic brine shrimp Artemia (Branchiopoda: Anostraca) in commercial cyst lots from Great Salt Lake, UT, USA

The brine shrimp Artemia is one of the most studied animals in the world. A large part of the knowledge of this crustacean is based on cysts harvested from two main sources; the Great Salt Lake, UT (GSL), and the San Francisco Bay salterns, CA (SFB), USA. Artemia populations from these habitats are recognized to belong to a single zygogenetic species, Artemia franciscana Kellogg, 1906. However, the GSL Artemia has been in doubt for more than a century about the existence of parthenogenetic reproduction. By using morphological, reproductive, and molecular analyses, we report that commercial GSL cyst lots contained two different brine shrimp species; a parthenogenetic (60%) and a zygogenetic (A. franciscana) (40%). From this finding, at least three hypotheses can be drawn. The parthenogenetic Artemia is native of GSL, or it was introduced to GSL, or foreign parthenogenetic cysts were mixed with A. franciscana cysts and canned for commercial distribution. Researchers using brine shrimp cysts from GSL should therefore pay careful attention to the correct identity of the species under study. The potential of an easy and unnoticed introduction of parthenogenetic Artemia into America is discussed.     

Arbuscular mycorrhizal fungi enhance fruit growth and quality of chile ancho (Capsicum annuum L. cv San Luis) plants exposed to drought

The effect of arbuscular mycorrhizal fungi (AMF) and drought on fruit quality was evaluated in chile ancho (Capsicum annuum L. cv San Luis). AMF treatments were (1) Glomus fasciculatum (AMFG), (2) a fungal species consortium from the forest “Los Tuxtla” in Mexico (AMFT), (3) a fungal species consortium from the Sonorian desert in Mexico (AMFD), and (4) a noninoculated control (NAMF). Plants were exposed to a 26-day drought cycle. Fruit quality was determined by measuring size (length, width, and pedicel length), color, chlorophyll, and carotenoid concentration. Under nondrought conditions, AMFG produced fruits that were 13% wider and 15% longer than the NAMF treatment. Under nondrought conditions, fruit fresh weight was 25% greater in the AMFG treatment compared to the NAMF. Under drought, fruits in the AMFT and AMFD treatments showed fresh weights similar to those in the NAMF treatment not subjected to drought. Fruits of the AMFG treatment subjected to drought showed the same color intensity and chlorophyll content as those of the nondroughted NAMF treatment and carotenoid content increased 1.4 times compared to that in the NAMF not exposed to drought. It is interesting to note that fruits in the AMFD treatment subjected to drought and the NAMF treatment not exposed to drought reached the same size. AMFD treatment increased the concentration of carotenes (1.4 times) under nondrought conditions and the concentration of xanthophylls (1.5 times) under drought when compared to the nondroughted NAMF treatment.     

Branchinecta oterosanvicentei n. sp. (Branchiopoda: Anostraca), a new fairy shrimp from the Chihuahuan desert, with a proposal for the conservation of the Branchinectidae of Mexico

Branchinecta oterosanvicentei, new species, a fairy shrimp endemic to the south of Coahuila, Mexico is described and figured. Differential features between the new species and the related B. lindahli are discussed on the basis of a SEM micrographs. The main diagnostic characters of Branchinecta oterosanvicentei are: (1) a pulvinus covered by scales localized on the middle of the median side of the proximal article of antenna, and (2) a network of prominent cortical crests on the cyst surface. Of seven Branchinecta species occurring in Mexico, four (B. belki, B. mexicana, B. oterosanvicentei, and B. sandiegonensis) have a restricted geographic range. Because, in addition, extreme fluctuations in the number of mature individuals per population occur, the survival of all of these species is threatened, and measures should be taken to protect them. Branchinecta mackini has a wide distribution in North America, but even this form is rare in Mexico.