Piper viridescens sp. nov. (Piperaceae) from Thailand

Piper viridescens sp. nov. is proposed based on material from northern Thailand. The new species is described and illustrated, resulting from a revision of the genus in Thailand. The new species is most closely related to P. boehmeriifolium (Miq.) C. DC. A table comparing diagnostic features of P. viridescens, P. boehmeriifolium and P. retrofractum is provided.     

Autonomic control of heart rate in the adult, aquatic Notophthalmus viridescens viridescens

1. We investigated the role of the autonomic nervous system in the control of the heart rate using an isolated heart preparation. 2. Addition of the parasympathetic blocker, atropine, to the organ bath resulted in an increase in heart rate as expected. 3. Addition of the sympathetic blocker, ergotamine, to the organ bath showed no change in the heart rate. 4. Addition of the sympathetic blocker, propranolol, to the organ bath resulted in the expected decrease in heart rate. 5. Both the sympathetic and parasympathetic nervous systems appear to play a role in the control of the heart rate.     

Cordyceps owariensis f. viridescens and its new Nomuraea anamorph

Cordyceps owariensis f. viridescens forma nov. (Nom. Jap., Amami-yarinohosemitake) is described from an underground nymph of Platypleura kuroiwae collected in Amami-oshima Island, southwestern Japan. Cultural isolations were made from ascospores of the fresh material of this fungus, and consequently a new hyphomycete was developed as its anamorph. Nomuraea owariensis is described to accommodate this anamorphic state. This is the first report on the association of a Nomuraea anamorph with cicadicolous Cordyceps species. Received: June 6, 2001 / Accepted: December 18, 2001     

Regenerative abnormalities in Notophthalmus viridescens induced by repeated amputations.

The fidelity of the regenerative response in the adult newt, Notophthalmus viridescens, was examined following repeated amputations at the level of the distal one-third of humerus. Three to four months following amputation, all regenerates were scored for gross morphology, reamputated, and stained with methylene blue for skeletal elements. The occurrence of abnormal regeneration with respect both to gross morphology and to skeletal structure was found to increase directly with the number of times the limb stumps were required to initiate dedifferentiation and repair. The initial amputation-regeneration process produced structurally normal replacement limbs in 91% of the cases examined. Reamputations of 4-digit regenerates (3--4 months after the previous transection) resulted in structurally abnormal regenerates in 28% of the cases following two amputations; 50% of the cases following three amputations; 65% of the cases following four amputations; and 81% of the cases following five amputations. The relationships between repeated dedifferentiation, proliferation, and redifferentiation and normal limb development are discussed.     

Development of Notophthalmus viridescens embryos

Although the North American, adult, red-spotted newt has been an excellent model in the study of appendage regeneration at the tissue and cell levels, experiments involving embryonic forms have been essentially impossible to perform at the molecular level due to the great difficulty in breeding newts in the laboratory. Recently, we reported our methods to successfully spawn many thousands of embryos of Notophthalmus viridescens for developmental studies on a year round basis. As no detailed examination of embryogenesis of this amphibian exists, we provide a scanning electron microscopic overview of N. viridescens development. Furthermore, we chronicle the life cycle of the newt, when produced under laboratory conditions, which also undergoes two metamorphoses as newts in the wild.     

5S ribosomal RNA genes of the newt Notophthalmus viridescens.

The genes which code for the 5S ribosomal RNA in the newt, Notophthalmus viridescens have been cloned and analyzed. Two types of repeating unit were detected: a major type consisting of a 120 bp coding region with a 111 bp spacer, and a minor type composed of a coding region, a pseudogene, and a 113 bp spacer. The pseudogene is a 36 bp segment which corresponds to the 3' terminal third of the 5S RNA gene, and is situated immediately 3' to the gene, being separated from it by 2 bp. Two recombinant plasmids were obtained in which the major and minor units were arranged in an interspersed pattern.     

DNA synthesis in the thymus of the adult newt Notophthalmus viridescens.

Lymphocytic activity was examined in thymuses of adult newts by studying the number, location, morphology and fate of cells within thymuses which had been processed for autoradiography 15 min, 2 and 4 h, and 2, 4, and 10 days subsequent to the injection of tritiated thymidine. Results of this study indicate (1) that the adult thymus is a highly proliferative organ, (2) that large and medium-sized lymphocytes present in the peripheral parenchyma give rise to smaller lymphocytes which move centrally and emigrate from the thymus, and (3) that many thymocytes leave the thymus within 2-4 days after they have been produced. The significance of these findings is discussed.     

Functional equivalency of created and natural wetlands: diet composition of red-spotted newts (Notophthalmus viridescens viridescens)

Evaluating the adequacy of created wetlands to replace functions of lost natural wetlands is important because wetland mitigation is a major tool used to offset wetland losses. However, measurements such as vegetative cover and wildlife presence may not be evidence enough that created wetlands are functioning properly and thus, examining the ecology of wetland biota such as amphibians may be a more useful surrogate for function. Our objectives were to measure the diet composition of adult red-spotted newts (Notophthalmus viridescens viridescens) and compare the selection of prey by newts between created and natural wetlands. Newts were trapped during the spring and summer of 2009 and 2010, and the stomach contents of 149 newts were obtained with gastric lavage. Invertebrate prey availability was obtained within a 5 m radius of each captured newt. Selection of prey by newts was nonrandom, but was only minimally affected by wetland type. Both dietary breadth and prey selection were affected primarily by time of year, likely driven by temporal variation in invertebrate abundance. Our results suggest that the function of providing an adequate prey base for a generalist wetland predator such as the red-spotted newt is being fulfilled for the created wetlands that we examined.     

Changes in cyclic GMP levels during forelimb regeneration in adult Notophthalmus viridescens.

Cyclic 3', 5'-guanosine monophosphate (cGMP) was measured at eight stages of forelimb regeneration in adult newts and compared with the cGMP levels of non-regenerating control limbs. There was a significant increase in cGMP content during dedifferentiation followed by a sharp decrease to minimal levels at the cone stage. A second smaller increase in cGMP occurred between the cone stage and mid-differentiation, followed by a decrease to relatively constant levels approaching control values as differentiation progressed. The changes in cGMP during dedifferentiation and during the period of highest cell proliferation indicate that cGMP may play a role in these processes. The smaller increases in cGMP levels during differentiation may reflect a reduced rate of cell division in the differentiating tissues.     

Characterization of a cloned histone gene cluster of the newt Notophthalamus viridescens.

We report the cloning and characterization of a histone gene cluster of the newt Notophthalamus viridescens. Fragments containing newt histone genes were identified in whole genome Southern blots; these fragments were cloned into a bacteriophage lambda cloning vector constructed for this purpose. The positions of most of the histone genes were determined by hybridizing subcloned sea urchin histone genes to digests of the cloned newt gene cluster. The position of each gene was verified, and its polarity determined by sequencing a portion of each. The order of the genes in the cloned segment is H1-H3-H2B-H2A-H4, with each of the genes but H2B being transcribed in the same direction. Subcloned segments of the histone gene repeat were used to determine the size of each newt oocyte histone mRNA.     

Nucleotide sequence of Lactobacillus viridescens 5S RNA

The nucleotide sequence of Lactobacillus viridescens ATCC 12706 5S RNA was determined to be pU-G-U-U-G-U-G-A-U-G-A-U-G-G-C-A-U-U-G-A-G-G-U-C-A-C-A-C C-U-G-U-U-C-C-C-A-U-A-C-C-G-A-A-C-A-C-A-G-A-A-G-U-U-A-A-G-C-U-C-A-A-U-A-G-C-G C-C-G-A-A-A-G-U-A-G-U-U-G-G-A-G-G-A-U-C-U-C-U-U-C-C-U-G-C-G-A-G-G-A-U-A-G-G-A C-G-U-C-G-C-A-A-U-G-COH. When compared with other published sequences of prokaryotic 5S RNA species, this sequence shows as much homology with that from B. substilis (80% homology when all variations included) and B. megaterium (77% homology) as with the 5S RNA from another member of Lactobacillaceae family (L. brevis, 79% homology). The sequence contains the proposed tRNA binding site (CGAAC, positions 41-45) and can accomodate most, but not all, of the more recently proposed helical regions of secondary structure.     

Hemopoietic tissue in the adult newt,Notopthalmus viridescens

The presence of developmental stages of lymphocytes and their precurors, as revealed by serial and thin sections of hemopoietic organs of normal adult newts (Notopthalmus viridescens) suggests that lymphopoiesis is limited to the thymus, medulla of the spleen and, to a lesser degree, the intestine. Stromal cells, small lymphocytes, granulocytes, mature erythrocytes and melanocytes were observed either within or near the parenchyma of the thymus. The urodele thymus differs from the thymus of anurans and higher vertebrates in that it lacks a cortex and a medulla, myoid cells and Hassall's corpuscles.