Early Development and Putative Primordial Germ Cells Characterization in Dogs

Previously, three distinct populations of putative primordial germ cells (PGCs), namely gonocytes, intermediate cells and pre‐spermatogonia, have been described in the human foetal testis. According to our knowledge, these PGCs have not been studied in any other species. The aim of our study was to identify similar PGC populations in canine embryos. First, we develop a protocol for canine embryo isolation. Following our protocol, 15 canine embryos at 21–25 days of pregnancy were isolated by ovaryhysterectomy surgery. Our data indicate that dramatic changes occur in canine embryo development and PGCs specification between 21 to 25 days of gestation. At that moment, only two PGC populations with distinct morphology can be identified by histological analyses. Cell population 1 presented round nuclei with prominent nucleolus and a high nuclear to cytoplasm ratio, showing gonocyte morphology. Cell population 2 was often localized at the periphery of the testicular cords and presented typical features of PGC. Both germ cell populations were positively immunostained with anti‐human OCT‐4 antibody. However, at day 25, all cells of population 1 reacted positively with OCT‐4, whereas in population 2, fewer cells were positive for this marker. These two PGCs populations present morphological features similar to gonocytes and intermediate cells from human foetal testis. It is expected that a population of pre‐spermatogonia would be observed at later stages of canine foetus development. We also showed that anti‐human OCT‐4 antibody can be useful to identify canine PGC in vivo.     

Long-range electron transfer in heme proteins

Kinetic experiments have conclusively shown that electron transfer can take place over large distances (greater than 10 angstroms) through protein interiors. Current research focuses on the elucidation of the factors that determine the rates of long-range electron-transfer reactions in modified proteins and protein complexes. Factors receiving experimental and theoretical attention include the donor-acceptor distance, changes in geometry of the donor and acceptor upon electron transfer, and the thermodynamic driving force. Recent experimental work on heme proteins indicates that the electron-transfer rate falls off exponentially with donor-acceptor distance at long range. The rate is greatly enhanced in proteins in which the structural changes accompanying electron transfer are very small.     

A two-chambered trap reduces within-trap predation by octopus on rock lobsters in aquarium trials

A two-chambered lobster trap was developed that in aquarium trials significantly (p < 0.01) reduced octopus predation on trap-caught spiny lobster. The trap was designed using information gained from an investigation of the behavioural interactions of the maori octopus (Octopus maorum) with traps used in the South Australian commercial lobster (Jasus edwardsii) fishery. This study showed that octopuses were primarily attracted to traps by the presence of bait as opposed to lobsters and that octopus entry into traps was ‘fortuitous’ and mediated by speculative exploration. The outer chamber of the modified trap contained bait and allowed entry by octopuses but not lobster and the inner chamber allowed access to both animals. The trap worked on the principle that octopuses would enter the outer chamber containing bait via a side entrance in preference to entry to the inner chamber containing lobsters via the neck. This was found to be the case and lobster mortality was 70% lower in the two-chambered trap than a standard trap. Successful adaptation of this trap design to commercial fishing conditions could significantly reduce rates of octopus predation on rock lobsters in several important southern hemisphere fisheries for spiny lobsters.     

Buffalo (Bubalus bubali) Late Embryo and Foetus Development: A Morphological Analysis

Many researches describe the embryonic developmental features in domestic animals; however, in farm animals, they are scarce. Most farm animal studies are related to assisted reproduction and embryos transfer techniques. But, morphological features and size measure to estimate the age gestation are rarely reported in literature. Thus, in this study, we described the developmental changes in the bubaline (Bubalus bubali) concepts from 21 to 60 days of gestation. Our results revealed that buffalo embryos similar morphological characteristics similar to other mammalian species. Also, similarities between bovine and bubaline persist; except on foetal stages when buffalos have a faster development than bovine. Therefore, buffalo's gestation period exhibits some varieties and accurate embryo age is more difficult. Yet, when we use a combination of the crown–rump, macroscopic analysis and alizarin red, it is possible to describe better the whole embryogenesis stages of the buffalo and which can contribute for future reproduction researches and applications in veterinary practice.     

Tears of the palmar superficial fascia in five racing greyhounds and a Labrador retriever

Tears of the palmar superficial fascia over the palmar extremity of the accessory carpal bone were identified as the cause of lameness in five racing greyhounds and as a coincidental finding in a Labrador retriever with an avulsion of the insertion of the flexor carpi ulnaris tendon. The lameness in the greyhounds was mild and transient, although racing performance was affected. The Labrador retriever was severely lame. In all cases there was a marked soft tissue swelling and a palpable defect in the superficial fascia. One case was managed conservatively and surgical repair was performed in the remaining five cases. The greyhounds returned to successful racing and the Labrador retriever made a complete recovery.     

内蒙古大兴安岭森林分类区划存在的问题及建议

森林分类区划是为了解决天然林的修养生息和恢复发展而提出的,但禁伐区、限伐区、商品林经营区划分在实施过程中存在一些问题。文章主要针对其存在的问题,提出一些可行性的建议和对策。     

浅谈对森林认证的认识

文章通过对森林认证的特点、体系、机构、过程等方面的论述,阐述了森林认证对全球森林可持续经营的影响。