Yersinia entomophaga sp. nov., isolated from the New Zealand grass grub Costelytra zealandica.

A Gram-negative, rod-shaped, non-spore-forming bacterium (MH96(T)) was isolated from diseased larvae of the New Zealand grass grub, Costelytra zealandica (Coleoptera: Scarabaeidae). On the basis of 16S rRNA gene sequence similarity, strain MH96(T) is a member of the genus Yersinia, which is a member of the class Gammaproteobacteria. The most similar 16S rRNA gene sequence to that of MH96(T) is that of the type strain of Yersinia mollaretii (98.5 % similarity) followed by those of the type strains of Yersinia aldovae, Y. frederiksenii and Y. rohdei (all 98.4 % similarity). Multilocus sequence typing of five housekeeping genes (dnaJ, glnA, gyrB, groEL and recA) identified Yersinia ruckeri (81-92 % similarity) as the closest relative. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain MH96(T) from the four most closely related Yersinia species with validly published names, including a Y. ruckeri isolate. Strain MH96(T) therefore represents a novel species, for which the name Yersinia entomophaga sp. nov. is proposed, with the type strain MH96(T) ( = DSM 22339(T)  = ATCC BAA-1678(T)).

Beauveria caledonica is a naturally occurring pathogen of forest beetles.

In New Zealand, two introduced scolytid beetles, Hylastes ater and Hylurgus ligniperda (Curculionidae: Scolytinae) are pests in pine plantations. Investigation of the naturally occurring pathogens of these exotic pests revealed that both are attacked by Beauveria caledonica, a species originally isolated and described from soil in Scotland. The isolates in New Zealand were identical in morphology and conserved DNA region (rDNA, elongation factor alpha) sequence to isolates held in the USDA-ARS insect pathogens culture collection. In bioassay, the B. caledonica isolates were highly pathogenic to adults of H. ligniperda and larvae of Tenebrio molitor. Sporulation was observed on cadavers, confirming the species can utilise the cadavers. As both species were likely to have been introduced to New Zealand from Europe, a search was made for B. caledonica in the northern UK and Ireland. The fungus was found as a naturally-occurring pathogen of the weevil pest, Hylobius abietis (Curculionidae: Scolytinae), developing in spruce and other beetles in forests in both regions.

Weaning triggers a decrease in receptor activator of nuclear factor-kappaB ligand expression, widespread osteoclast apoptosis, and rapid recovery of bone mass after lactation in mice.

A significant portion of milk calcium comes from the mother's skeleton, and lactation is characterized by rapid bone loss. The most remarkable aspect of this bone loss is its complete reversibility, and the time after weaning is the most rapid period of skeletal anabolism in adults. Despite this, little is known of the mechanisms by which the skeleton repairs itself after lactation. We examined changes in bone and calcium metabolism defining the transition from bone loss to bone recovery at weaning in mice. Bone mass decreases during lactation and recovers rapidly after weaning. Lactation causes changes in bone microarchitecture, including thinning and perforation of trabecular plates that are quickly repaired after weaning. Weaning causes a rapid decline in urinary C-telopeptide levels and stimulates an increase in circulating levels of osteocalcin. Bone histomorphometry documented a significant reduction in the numbers of osteoclasts on d 3 after weaning caused by a coordinated wave of osteoclast apoptosis beginning 48 h after pup removal. In contrast, osteoblast numbers and bone formation rates, which are elevated during lactation, remain so 3 d after weaning. The cessation of lactation stimulates an increase in circulating calcium levels and a reciprocal decrease in PTH levels. Finally, weaning is associated with a decrease in levels of receptor activator of nuclear factor-kappaB ligand mRNA in bone. In conclusion, during lactation, bone turnover is elevated, and bone loss is rapid. Weaning causes selective apoptosis of osteoclasts halting bone resorption. The sudden shift in bone turnover favoring bone formation subsequently contributes to the rapid recovery of bone mass.